ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Parts
63,
264,
265,
266,
270
and
271
[
FRL­
]
RIN
2060­
National
Emission
Standards
for
Hazardous
Air
Pollutants:
Final
Standards
for
Hazardous
Air
Pollutants
for
Hazardous
Waste
Combustors
(
Phase
I
Final
Replacement
Standards
and
Phase
II)
AGENCY:
Environmental
Protection
Agency
(
EPA).
ACTION:
Final
rule.
SUMMARY:
This
action
finalizes
national
emission
standards
(
NESHAP)
for
hazardous
air
pollutants
for
hazardous
waste
combustors
(
HWCs):
hazardous
waste
burning
incinerators,
cement
kilns,
lightweight
aggregate
kilns,
industrial/
commercial/
institutional
boilers
and
process
heaters,
and
hydrochloric
acid
production
furnaces.
EPA
has
identified
HWCs
as
major
sources
of
hazardous
air
pollutant
(
HAP)
emissions.
These
standards
implement
section
112(
d)
of
the
Clean
Air
Act
(
CAA)
by
requiring
hazardous
waste
combustors
to
meet
HAP
emission
standards
reflecting
the
performance
of
the
maximum
achievable
control
technology
(
MACT).
The
HAP
emitted
by
HWCs
include
arsenic,
beryllium,
cadmium,
chromium,
dioxins
and
furans,
hydrogen
chloride
and
chlorine
gas,
lead,
manganese,
and
mercury.
Exposure
to
these
substances
has
been
demonstrated
to
cause
adverse
health
effects
such
as
irritation
to
the
lung,
skin,
and
mucus
membranes,
effects
on
the
central
nervous
system,
kidney
damage,
and
cancer.
The
adverse
health
effects
associated
with
exposure
to
these
specific
HAP
are
further
described
in
the
preamble.
For
many
HAP,
these
findings
have
only
been
shown
with
concentrations
higher
than
those
typically
in
the
ambient
air.
This
action
also
presents
our
decision
regarding
the
February
28,
2002
petition
for
rulemaking
submitted
by
the
Cement
Kiln
Recycling
Coalition,
relating
to
EPA's
implementation
of
the
so­
called
omnibus
permitting
authority
under
section
3005(
c)
of
the
Resource
Conservation
and
Recovery
Act
(
RCRA).
That
section
requires
that
each
permit
issued
under
RCRA
contain
such
terms
and
conditions
as
permit
writers
determine
to
be
necessary
to
protect
human
health
and
the
environment.
In
that
petition,
the
Cement
Kiln
Recycling
Coalition
requested
that
we
repeal
the
existing
site­
specific
risk
assessment
policy
and
technical
guidance
for
hazardous
waste
combustors
and
that
we
promulgate
the
policy
and
guidance
as
rules
in
accordance
with
the
Administrative
Procedure
Act
if
we
continue
to
believe
that
site­
specific
risk
assessments
may
be
necessary.
DATES:
The
final
rule
is
effective
[
INSERT
DATE
60
DAYS
FROM
DATE
OF
PUBLICATION]
ADDRESSES:
The
official
public
docket
is
the
collection
of
materials
that
is
available
for
public
viewing
at
the
Office
of
Air
and
Radiation
Docket
and
Information
Center
(
Air
Docket)
in
the
EPA
Docket
Center,
Room
B
 
102,
1301
Constitution
Ave.,
NW.,
Washington,
DC.
FOR
FURTHER
INFORMATION
CONTACT:
For
more
information
concerning
applicability
and
rule
determinations,
contact
your
State
or
local
representative
or
appropriate
EPA
Regional
Office
representative.
For
information
concerning
rule
development,
contact
Michael
Galbraith,
Waste
Treatment
Branch,
Hazardous
Waste
Minimization
and
Management
Division,
(
5302W),
U.
S.
EPA,
1200
Pennsylvania
Avenue,
NW.,
Washington
DC
20460,
telephone
number
(
703)
605­
0567,
fax
number
(
703)
308­
8433,
electronic
mail
address
galbraith.
michael@
epa.
gov
SUPPLEMENTARY
INFORMATION:
Regulated
Entities
The
promulgation
of
the
final
rule
would
affect
the
following
North
American
Industrial
Classification
System
(
NAICS)
and
Standard
Industrial
Classification
(
SIC)
codes:

Category
NAICS
code
SIC
code
Examples
of
potentially
regulated
entities
Any
industry
that
combusts
hazardous
waste
as
defined
in
the
final
rule
562211
327310
327992
325
324
331
333
488,
561,
562
421
422
512,
541,
561,
812
512,
514,
541,
711
924
4953
3241
3295
28
29
33
38
49
50
51
73
89
95
Incinerator,
hazardous
waste
Cement
manufacturing,
clinker
production
Ground
or
treated
mineral
and
earth
manufacturing
Chemical
Manufacturers
Petroleum
Refiners
Primary
Aluminum
Photographic
equipment
and
supplies
Sanitary
Services,
N.
E.
C.
Scrap
and
waste
materials
Chemical
and
Allied
Products,
N.
E.
C
Business
Services,
N.
E.
C.
Services,
N.
E.
C.
Air,
Water
and
Solid
Waste
Management
This
table
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
likely
to
be
regulated
by
this
action.
This
table
lists
examples
of
the
types
of
entities
EPA
is
now
aware
could
potentially
be
regulated
by
this
action.
Other
types
of
entities
not
listed
could
also
be
affected.
To
determine
whether
your
facility,
company,
business,
organization,
etc.,
is
regulated
by
this
action,
you
should
examine
the
applicability
criteria
in
Part
II
of
this
preamble.
If
you
have
any
questions
regarding
the
applicability
of
this
action
to
a
particular
entity,
consult
the
person
listed
in
the
preceding
FOR
FURTHER
INFORMATION
CONTACT
section.

Abbreviations
and
Acronyms
Used
in
This
Document
acfm
actual
cubic
feet
per
minute
Btu
British
thermal
units
CAA
Clean
Air
Act
CFR
Code
of
Federal
Regulations
DRE
destruction
and
removal
efficiency
dscf
dry
standard
cubic
foot
dscm
dry
standard
cubic
meter
EPA
Environmental
Protection
Agency
FR
Federal
Register
gr/
dscf
grains
per
dry
standard
cubic
foot
HAP
hazardous
air
pollutant(
s)
ICR
Information
Collection
Request
kg/
hr
kilograms
per
hour
kW­
hour
kilo
Watt
hour
MACT
Maximum
Achievable
Control
Technology
mg/
dscm
milligrams
per
dry
standard
cubic
meter
MMBtu
million
British
thermal
unit
ng/
dscm
nanograms
per
dry
standard
cubic
meter
NESHAP
national
emission
standards
for
HAP
ng
nanograms
POHC
principal
organic
hazardous
constituent
ppmv
parts
per
million
by
volume
ppmw
parts
per
million
by
weight
Pub.
L.
Public
Law
RCRA
Resource
Conservation
and
Recovery
Act
SRE
system
removal
efficiency
TEQ
toxicity
equivalence
ug/
dscm
micrograms
per
dry
standard
cubic
meter
U.
S.
C.
United
States
Code
Table
of
Contents
Part
One:
Background
and
Summary
I.
What
Is
the
Statutory
Authority
for
this
Standard?
II.
What
Is
the
Regulatory
Development
Background
of
the
Source
Categories
in
the
Final
Rule?
A.
Phase
I
Source
Categories
B.
Phase
II
Source
Categories
III.
How
Was
the
Final
Rule
Developed?
IV.
What
Is
the
Relationship
Between
the
Final
Rule
and
Other
MACT
Combustion
Rules?
V.
What
Are
the
Health
Effects
Associated
with
Pollutants
Emitted
by
Hazardous
Waste
Combustors?
Part
Two:
Summary
of
the
Final
Rule
I.
What
Source
Categories
and
Subcategories
Are
Affected
by
the
Final
Rule?
II.
What
Are
the
Affected
Sources
and
Emission
Points?
III.
What
Pollutants
Are
Emitted
and
Controlled?
IV.
Does
the
Final
Rule
Apply
to
Me?
V.
What
Are
the
Emission
Limitations?
VI.
What
Are
the
Testing
and
Initial
Compliance
Requirements?
A.
Compliance
Dates
B.
Testing
Requirements
C.
Initial
Compliance
Requirements
VII.
What
Are
the
Continuous
Compliance
Requirements?
VIII.
What
Are
the
Notification,
Recordkeeping,
and
Reporting
Requirements?
IX.
What
Is
the
Health­
Based
Compliance
Alternative
for
Total
Chlorine,
and
How
Do
I
Demonstrate
Eligibility?
A.
Overview
B.
HCl­
Equivalent
Emission
Rates
C.
Eligibility
Demonstration
D.
Assurance
that
the
1­
Hour
HCl­
Equivalent
Emission
Rate
Will
Not
Be
Exceeded
E.
Review
and
Approval
of
Eligibility
Demonstrations
F.
Testing
Requirements
G.
Monitoring
Requirements
H.
Relationship
Among
Emission
Rates,
Emission
Rate
Limits,
and
Feedrate
Limits
I.
Changes
X.
Overview
on
Floor
Methodologies
Part
Three:
What
Are
the
Major
Changes
Since
Proposal?
I.
Database
A.
Hazardous
Burning
Incinerators
B.
Hazardous
Waste
Cement
Kilns
C.
Hazardous
Waste
Lightweight
Aggregate
Kilns
D.
Liquid
Fuel
Boilers
E.
HCl
Production
Furnaces
F.
Total
Chlorine
Emissions
Data
Below
20
ppmv
II.
Emission
Limits
A.
Incinerators
B.
Hazardous
Waste
Burning
Cement
Kilns
C.
Hazardous
Waste
Burning
Lightweight
Aggregate
Kilns
D.
Solid
Fuel
Boilers
E.
Liquid
Fuel
Boilers
F.
Hydrochloric
Acid
Production
Furnaces
G.
Dioxin/
Furan
Testing
for
Sources
Not
Subject
to
a
Numerical
Standard
III.
Statistics
and
Variability
A.
Using
Statistical
Imputation
to
Address
Variability
of
Nondetect
Values
B.
Degrees
of
Freedom
when
Imputing
a
Standard
Deviation
Using
the
Universal
Variability
Factor
for
Particulate
Matter
Controlled
by
a
Fabric
Filter
IV.
Compliance
Assurance
for
Fabric
Filters,
Electrostatic
Precipitators,
and
Ionizing
Wet
Scrubbers
V.
Health­
Based
Compliance
Alternative
for
Total
Chlorine
Part
Four:
What
Are
the
Responses
to
Major
Comments?
I.
Database
A.
Revisions
to
the
EPA's
Hazardous
Waste
Combustor
Data
Base
B.
Use
of
Data
from
Recently
Upgraded
Sources
C.
Correction
of
Total
Chlorine
Data
to
Address
Potential
Bias
in
Stack
Measurement
Method
D.
Mercury
Data
for
Cement
Kilns
E.
Mercury
Data
for
Lightweight
Aggregate
Kilns
F.
Incinerator
Database
II.
Affected
Sources
A.
Area
Source
Boilers
and
Hydrochloric
Acid
Production
Furnaces
B.
Boilers
Eligible
for
the
RCRA
Low
Risk
Waste
Exemption
C.
Mobile
Incinerators
III.
Floor
Approaches
A.
Variability
B.
SRE/
Feed
Methdology
C.
Air
Pollution
Control
Technology
Methodologies
for
the
Particulate
Matter
Standard
and
for
the
Total
Chlorine
Standard
for
Hydrochloric
Acid
Production
Furnaces
D.
Format
of
Standards
E.
Standards
Can
Be
No
Less
Stringent
Than
the
Interim
Standards
F.
How
Can
EPA's
Approach
to
Assessing
Variability
and
its
Ranking
Methodologies
be
Reasonable
when
they
Result
in
Standards
Higher
than
the
Interim
Standards?
IV.
Use
of
Surrogates
A.
Particulate
Matter
as
Surrogate
for
Metal
HAP
B.
Carbon
Monoxide/
Hydrocarbons
and
DRE
as
Surrogates
for
Dioxin/
Furan
C.
Use
of
Carbon
Monoxide
and
Total
Hydrocarbons
as
Surrogate
for
Non­
Dioxin
Organic
HAP
V.
Additional
Issues
Relating
to
Variability
and
Statistics
A.
Data
Sets
Containing
Nondetects
B.
Using
Statistical
Imputation
to
Address
Variability
of
Nondetect
Values
C.
Analysis
of
Variance
Procedures
to
Assess
Subcategorization
VI.
Emission
Standards
A.
Incinerators
B.
Cement
Kilns
C.
Lightweight
Aggregate
Kilns
D.
Liquid
Fuel
Boilers
E.
General
VII.
Health­
Based
Compliance
Alternative
for
Total
Chlorine
A.
Authority
for
Health­
Based
Compliance
Alternatives
B.
Implementation
of
the
Health­
Based
Standards
C.
National
Health­
Based
Standards
for
Cement
Kilns.
VIII.
Implementation
and
Compliance
A.
Compliance
Assurance
Issues
for
both
Fabric
Filters
and
Electrostatic
Precipitators
(
and
Ionizing
Wet
Scrubbers)
B.
Compliance
Assurance
Issues
for
Fabric
Filters
C.
Compliance
Issues
for
Electrostatic
Precipitators
and
Ionizing
Wet
Scrubbers
D.
Fugitive
Emissions
E.
Notification
of
Intent
to
Comply
and
Compliance
Progress
Report
F.
Startup,
Shutdown,
and
Malfunction
Plan
G.
Public
Notice
of
Test
Plans
H.
Using
Method
23
Instead
of
Method
0023A
I.
Extrapolating
Feedrate
Limits
for
Compliance
with
the
Liquid
Fuel
Boiler
Mercury
and
Semivolatile
Metal
Standards
J.
Temporary
Compliance
with
Alternative,
Otherwise
Applicable
MACT
Standards
K.
Periodic
DRE
Testing
and
Limits
on
Minimum
Combustion
Chamber
Temperature
for
Cement
Kilns
L.
One
Time
Dioxin
and
Furan
Test
for
Sources
Not
Subject
to
a
Numerical
Limit
for
Dioxin
and
Furan
M.
Miscellaneous
Compliance
Issues
IX.
Site­
Specific
Risk
Assessment
under
RCRA
A.
What
Is
the
Site­
Specific
Risk
Assessment
Policy?
B.
Why
Might
SSRAs
Continue
To
Be
Necessary
for
Sources
Complying
With
Phase
1
Replacement
Standards
and
Phase
2
Standards?
C.
What
Changes
Are
EPA
Finalizing
With
Respect
To
the
Site­
Specific
Risk
Assessment
Policy?
D.
How
Will
the
New
SSRA
Regulatory
Provisions
Work?
E.
What
Were
Commenters'
Reactions
to
EPA's
Proposed
Decision
Not
to
Provide
National
Criteria
for
Determining
When
an
SSRA
Is
or
Is
Not
Necessary?
F.
What
Are
EPA's
Responses
to
the
Cement
Kiln
Recycling
Coalition's
Comments
on
the
Proposal
and
What
is
EPA's
Final
Decision
on
CKRC's
Petition?
X.
Permitting
A.
What
is
the
Statutory
Authority
for
the
RCRA
Requirements
Discussed
in
this
Section?
B.
Did
Commenters
Express
any
Concerns
Regarding
the
Current
Permitting
Requirements?
C.
Are
There
Any
Changes
to
the
Proposed
Class
1
Permit
Modification
Procedure?
D.
What
Permitting
Approach
Is
EPA
Finalizing
for
New
Units?
E.
What
Other
Permitting
Requirements
Were
Discussed
In
the
Proposal?
Part
Five:
What
Are
the
CAA
Delegation
Clarifications
and
RCRA
State
Authorization
Requirements?
I.
Authority
for
this
Rule.
II.
CAA
Delegation
Authority.
III.
Clarifications
to
CAA
Delegation
Provisions
for
Subpart
EEE.
A.
Alternatives
to
Requirements.
B.
Alternatives
to
Test
Methods.
C.
Alternatives
to
Monitoring.
D.
Alternatives
to
Recordkeeping
and
Reporting.
E.
Other
Delegation
Provisions
IV.
RCRA
State
Authorization
and
Amendments
To
the
RCRA
Regulations.
Part
Six:
Impacts
of
the
Final
Rule
I.
What
Are
the
Air
Impacts?
II.
What
Are
the
Water
and
Solid
Waste
Impacts?
III.
What
Are
the
Energy
Impacts?
IV.
What
Are
the
Control
Costs?
V.
What
Are
the
Economic
Impacts?
A.
Market
Exit
Estimates
B.
Waste
Reallocations
VI.
What
Are
the
Social
Costs
and
Benefits
of
the
Final
Rule?
A.
Combustion
Market
Overview
B.
Baseline
Specification
C.
Analytical
Methodology
and
Findings
­
Social
Cost
Analysis
D.
Analytical
Methodology
and
Findings
­
Benefits
Assessment
Part
Seven:
How
Does
the
Final
Rule
Meet
the
RCRA
Protectiveness
Mandate?
I.
Background
II.
Evaluation
of
Protectiveness
Part
Eight:
Statutory
and
Executive
Order
Reviews
I.
Executive
Order
12866:
Regulatory
Planning
and
Review
II.
Paperwork
Reduction
Act
III.
Regulatory
Flexibility
Act
IV.
Unfunded
Mandates
Reform
Act
of
1995
V.
Executive
Order
13132:
Federalism
VI.
Executive
Order
13175:
Consultation
and
Coordination
with
Indian
Tribal
Governments
VII.
Executive
Order
13045:
Protection
of
Children
from
Environmental
Health
Risks
and
Safety
Risks
VIII.
Executive
Order
13211:
Actions
Concerning
Regulations
that
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
IX.
National
Technology
Transfer
and
Advancement
Act
X.
Executive
Order
12898:
Federal
Actions
to
Address
Environmental
Justice
in
Minority
Populations
and
Low­
Income
Populations
XI.
Congressional
Review
Part
One:
Background
and
Summary
I.
What
Is
the
Statutory
Authority
for
this
Standard?
Section
112
of
the
Clean
Air
Act
requires
that
the
EPA
promulgate
regulations
requiring
the
control
of
HAP
emissions
from
major
and
certain
area
sources.
The
control
of
HAP
is
achieved
through
promulgation
of
emission
standards
under
sections
112(
d)
and
(
in
a
second
round
of
standard
setting)
(
f).
EPA's
initial
list
of
categories
of
major
and
area
sources
of
HAP
selected
for
regulation
in
accordance
with
section
112(
c)
of
the
Act
was
published
in
the
Federal
Register
on
July
16,
1992
(
57
FR
31576).
Hazardous
waste
incinerators,
Portland
cement
plants,
clay
products
manufacturing
(
including
lightweight
aggregate
kilns),
industrial/
commercial/
institutional
boilers
and
process
heaters,
and
hydrochloric
acid
production
furnaces
are
among
the
listed
174
categories
of
sources.
The
listing
was
based
on
the
Administrator's
determination
that
these
sources
may
reasonably
be
anticipated
to
emit
one
or
more
of
the
186
listed
HAP
in
quantities
sufficient
to
designate
them
as
major
sources.
II.
What
Is
the
Regulatory
Development
Background
of
the
Source
Categories
in
the
Final
Rule?

Today's
notice
finalizes
standards
for
controlling
emissions
of
HAP
from
hazardous
waste
combustors:
incinerators,
cement
kilns,
lightweight
aggregate
kilns,
boilers,
process
heaters1,
and
hydrochloric
acid
production
furnaces
that
burn
hazardous
waste.
We
call
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
Phase
I
sources
because
we
have
already
promulgated
standards
for
those
source
categories.
We
call
boilers
and
hydrochloric
acid
production
furnaces
Phase
II
sources
because
we
intended
to
promulgate
MACT
standards
for
those
source
categories
after
promulgating
MACT
standards
for
Phase
I
sources.
The
regulatory
background
of
Phase
I
and
Phase
II
source
categories
is
discussed
below.

A.
Phase
I
Source
Categories
Phase
I
combustor
sources
are
regulated
under
the
Resource
Conservation
and
Recovery
Act
(
RCRA),
which
establishes
a
"
cradle­
to­
grave"
regulatory
structure
overseeing
the
safe
treatment,
storage,
and
disposal
of
hazardous
waste.
We
issued
RCRA
rules
to
control
air
emissions
from
hazardous
waste
burning
incinerators
in
1981,
40
CFR
Parts
264
and
265,
Subpart
O,
and
from
cement
kilns
and
lightweight
aggregate
kilns
that
burn
hazardous
waste
in
1991,
40
CFR
Part
266,
Subpart
H.
These
rules
rely
generally
on
riskbased
standards
to
assure
control
necessary
to
protect
human
health
and
the
environment,
the
applicable
RCRA
standard.
See
RCRA
section
3004
(
a)
and
(
q).
The
Phase
I
source
categories
also
are
subject
to
standards
under
the
Clean
Air
Act.
We
promulgated
standards
for
Phase
I
sources
on
September
30,
1999
(
64
FR
52828).
This
final
rule
is
referred
to
in
this
preamble
as
the
Phase
I
rule
or
1999
final
rule.
These
emission
standards
created
a
technology­
based
national
cap
for
hazardous
air
pollutant
emissions
from
the
combustion
of
hazardous
waste
in
these
devices.
The
rule
regulates
emissions
of
numerous
hazardous
air
pollutants:
dioxin/
furans,
other
toxic
organics
(
through
surrogates),
mercury,
other
toxic
metals
(
both
directly
and
through
a
surrogate),
and
hydrogen
chloride
and
chlorine
gas.
Where
necessary,
Section
3005(
c)(
3)
of
RCRA
provides
the
authority
to
impose
additional
conditions
on
a
source­
by­
source
basis
in
a
RCRA
permit
if
necessary
to
protect
human
health
and
the
environment.
A
number
of
parties,
representing
interests
of
both
industrial
sources
and
of
the
environmental
community,
sought
judicial
review
of
the
Phase
I
rule.
On
July
24,
2001,
the
United
States
Court
of
Appeals
for
the
District
of
Columbia
Circuit
granted
portions
of
the
Sierra
Club's
petition
for
review
and
vacated
the
challenged
portions
of
the
standards.
Cement
Kiln
Recycling
Coalition
v.
EPA,
255
F.
3d
855
(
D.
C.
Cir.
2001).
The
court
held
that
EPA
had
not
demonstrated
that
its
calculation
of
MACT
floors
met
the
statutory
requirement
of
being
no
less
stringent
than
(
1)
the
average
emission
limitation
achieved
by
the
best
performing
12
percent
of
existing
sources
and,
for
new
sources,
(
2)
the
emission
control
achieved
in
practice
by
the
best
controlled
similar
source
for
new
sources.
255
F.
3d
at
861,
865­
66.
As
a
remedy,
the
court,
after
declining
to
rule
on
most
of
the
issues
presented
in
the
industry
petitions
for
review,
vacated
the
"
challenged
regulations,"
stating
that:
"[
W]
e
have
chosen
not
to
reach
the
bulk
of
industry
petitioners'
claims,
and
leaving
the
regulations
1
A
process
heater
meets
the
RCRA
definition
of
a
boiler.
Therefore,
process
heaters
that
burn
hazardous
wastes
are
covered
under
subpart
EEE
as
boilers,
and
are
discussed
as
such
in
subsequent
parts
of
the
preamble.
in
place
during
remand
would
ignore
petitioners'
potentially
meritorious
challenges."
Id.
at
872.
Examples
of
the
specific
challenges
the
Court
indicated
might
have
merit
were
provisions
relating
to
compliance
during
start
up/
shut
down
and
malfunction
events,
including
emergency
safety
vent
openings,
the
dioxin/
furan
standard
for
lightweight
aggregate
kilns,
and
the
semivolatile
metal
standard
for
cement
kilns.
Id.
However,
the
Court
stated,
"[
b]
ecause
this
decision
leaves
EPA
without
standards
regulating
[
hazardous
waste
combustor]
emissions,
EPA
(
or
any
of
the
parties
to
this
proceeding)
may
file
a
motion
to
delay
issuance
of
the
mandate
to
request
either
that
the
current
standards
remain
in
place
or
that
EPA
be
allowed
reasonable
time
to
develop
interim
standards."
Id.
Acting
on
this
invitation,
all
parties
moved
the
Court
jointly
to
stay
the
issuance
of
its
mandate
for
four
months
to
allow
EPA
time
to
develop
interim
standards,
which
would
replace
the
vacated
standards
temporarily,
until
final
standards
consistent
with
the
Court's
mandate
are
promulgated.
The
interim
standards
were
published
on
February
13,
2002
(
67
FR
6792).
EPA
did
not
justify
or
characterize
these
standards
as
conforming
to
MACT,
but
rather
as
an
interim
measure
to
prevent
adverse
consequences
that
would
result
from
the
regulatory
gap
resulting
from
no
standards
being
in
place.
Id.
at
6793,
6795­
96;
see
also
69
FR
at
21217
(
April
20,
2004).
EPA
also
entered
into
a
settlement
agreement,
enforceable
by
the
Court
of
Appeals,
to
issue
final
standard
conforming
to
the
Court's
mandate
by
June
14,
2005.
That
date
has
since
been
extended
to
September
14,
2005.

B.
Phase
II
Source
Categories
Phase
II
combustors
­­
boilers
and
hydrochloric
acid
production
furnaces
­
­
are
also
regulated
under
the
Resource
Conservation
and
Recovery
Act
(
RCRA)
pursuant
to
40
CFR
Part
266,
Subpart
H,
and
(
for
reasons
discussed
below)
are
also
subject
to
the
MACT
standard
setting
process
in
section
112(
d)
of
the
CAA.
We
delayed
promulgating
MACT
standards
for
these
source
categories
pending
reevaluation
of
the
MACT
standard­
setting
methodology
following
the
Court's
decision
to
vacate
the
standards
for
the
Phase
I
source
categories.
We
also
have
entered
into
a
judicially
enforceable
consent
decree
with
Sierra
Club
that
requires
EPA
to
promulgate
MACT
standards
for
the
Phase
II
sources
by
June
14,
2005,
since
extended
to
September
14,
2005
­­
the
same
date
that
(
for
independent
reasons)
is
required
for
the
replacement
standards
for
Phase
I
sources.

III.
How
Was
the
Final
Rule
Developed?

We
proposed
standards
for
HWCs
on
April
20,
2004
(
69
FR
21197).
The
public
comment
period
closed
on
July
6,
2004.
In
addition,
on
February
4,
2005,
we
requested
certain
key
commenters
to
comment
by
email
on
a
limited
number
of
issues
arising
from
public
comments
on
the
proposed
rule.
The
comment
period
for
those
issues
closed
on
March
7,
2005.
We
received
approximately
100
public
comment
letters
on
the
proposed
rule
and
the
subsequent
direct
request
for
comments.
Comments
were
submitted
by
owner/
operators
of
HWCs,
trade
associations,
state
regulatory
agencies
and
their
representatives,
and
environmental
groups.
Today's
final
rule
reflects
our
consideration
of
all
of
the
comments
and
additional
information
we
received.
Major
public
comments
on
the
proposed
rule
along
with
our
responses,
are
summarized
in
this
preamble.
IV.
What
Is
the
Relationship
Between
the
Final
Rule
and
Other
MACT
Combustion
Rules?

The
amendments
to
the
Subpart
EEE,
Part
63,
standards
for
hazardous
waste
combustors
apply
to
the
source
categories
that
are
currently
subject
to
that
subpart­­
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
that
burn
hazardous
waste.
Today's
final
rule,
however,
also
amends
Subpart
EEE
to
establish
MACT
standards
for
the
Phase
II
source
categories­­
those
boilers
and
hydrochloric
acid
production
furnaces
that
burn
hazardous
waste.
Generally
speaking,
you
are
an
affected
source
pursuant
to
Subpart
EEE
if
you
combust,
or
have
previously
combusted,
hazardous
waste
in
an
incinerator,
cement
kiln,
lightweight
aggregate
kiln,
boiler,
or
hydrochloric
acid
production
furnace.
You
continue
to
be
an
affected
source
until
you
cease
burning
hazardous
waste
and
initiate
closure
requirements
pursuant
to
RCRA.
Affected
sources
do
not
include:
(
1)
Sources
exempt
from
regulation
under
40
CFR
part
266,
subpart
H,
because
the
only
hazardous
waste
they
burn
is
listed
under
40
CFR
266.100(
c);
(
2)
research,
development,
and
demonstration
sources
exempt
under
§
63.1200(
b);
and
(
3)
boilers
exempt
from
regulation
under
40
CFR
part
266,
subpart
H,
because
they
meet
the
definition
of
small
quantity
burner
under
40
CFR
266.108.
See
§
63.1200(
b).
If
you
never
previously
combusted
hazardous
waste,
or
have
ceased
burning
hazardous
waste
and
initiated
RCRA
closure
requirements,
you
are
not
subject
to
Subpart
EEE.
Rather,
EPA
has
promulgated
separate
MACT
standards
for
sources
that
do
not
burn
hazardous
waste
within
the
following
source
categories:
commercial
and
industrial
solid
waste
incinerators
(
40
CFR
Part
60,
Subparts
CCCC
and
DDDD);
Portland
cement
manufacturing
facilities
(
40
CFR
Part
63,
Subpart
LLL);
industrial/
commercial/
institutional
boilers
and
process
heaters
(
40
CFR
Part
63,
Subpart
DDDDD);
and
hydrochloric
acid
production
facilities
(
40
CFR
Part
63,
Subpart
NNNNN).
In
addition,
EPA
considered
whether
to
establish
MACT
standards
for
lightweight
aggregate
manufacturing
facilities
that
do
not
burn
hazardous
waste,
and
determined
that
they
are
not
major
sources
of
HAP
emissions.
Thus,
EPA
has
not
established
MACT
standards
for
lightweight
aggregate
manufacturing
facilities
that
do
not
burn
hazardous
waste.
Note
that
non­
stack
emissions
points
are
not
regulated
under
Subpart
EEE.
2
Emissions
attributable
to
storage
and
handling
of
hazardous
waste
prior
to
combustion
(
i.
e.,
emissions
from
tanks,
containers,
equipment,
and
process
vents)
would
continue
to
be
regulated
pursuant
to
either
RCRA
Subpart
AA,
BB,
and
CC
and/
or
an
applicable
MACT
that
applies
to
the
before­
mentioned
material
handling
devices.
Emissions
unrelated
to
the
hazardous
waste
operations
may
be
regulated
pursuant
to
other
MACT
rulemakings.
For
example,
Portland
cement
manufacturing
facilities
that
combust
hazardous
waste
are
subject
to
both
Subpart
EEE
and
Subpart
LLL,
and
hydrochloric
acid
production
facilities
that
combust
hazardous
waste
may
be
subject
to
both
Subpart
EEE
and
Subpart
NNNNN.
3
In
2
Note,
however,
that
fugitive
emissions
attributable
to
the
combustion
of
hazardous
waste
from
the
combustion
device
are
regulated
pursuant
to
Subpart
EEE.

3
Hydrochloric
acid
production
furnaces
that
combust
hazardous
waste
are
also
affected
sources
subject
to
Subpart
NNNNN
if
they
produce
a
liquid
acid
product
that
contains
greater
than
30%
hydrochloric
acid.
these
instances
Subpart
EEE
controls
HAP
emissions
from
the
cement
kiln
and
hydrochloric
acid
production
furnace
stack,
while
Subparts
LLL
and
NNNNN
would
control
HAP
emissions
from
other
operations
that
are
not
directly
related
to
the
combustion
of
hazardous
waste
(
e.
g.,
clinker
cooler
emissions
for
cement
production
facilities,
and
hydrochloric
acid
product
transportation
and
storage
for
hydrochloric
acid
production
facilities).
Note
that
if
you
temporarily
cease
burning
hazardous
waste
for
any
reason,
you
remain
an
affected
source
and
are
still
subject
to
the
applicable
Subpart
EEE
requirements.
However,
even
as
an
affected
source,
the
emission
standards
or
operating
limits
do
not
apply
if:
1)
hazardous
waste
is
not
in
the
combustion
chamber
and
you
elect
to
comply
with
other
MACT
(
or
CAA
section
129)
standards
that
otherwise
would
be
applicable
if
you
were
not
burning
hazardous
waste,
e.
g.,
the
nonhazardous
waste
burning
Portland
Cement
Kiln
MACT
(
Subpart
LLL);
or
(
2)
you
are
in
a
startup,
shutdown,
or
malfunction
mode
of
operation.

V.
What
Are
the
Health
Effects
Associated
with
Pollutants
Emitted
by
Hazardous
Waste
Combustors?

Today's
final
rule
protects
air
quality
and
promotes
the
public
health
by
reducing
the
emissions
of
some
of
the
HAP
listed
in
Section
112(
b)(
1)
of
the
CAA.
Emissions
data
collected
in
the
development
of
this
final
rule
show
that
metals,
hydrogen
chloride
and
chlorine
gas,
dioxins
and
furans,
and
other
organic
compounds
are
emitted
from
hazardous
waste
combustors.
The
HAP
that
would
be
controlled
with
this
rule
are
associated
with
a
variety
of
adverse
health
affects.
These
adverse
health
effects
include
chronic
health
disorders
(
e.
g.,
irritation
of
the
lung,
skin,
and
mucus
membranes
and
effects
on
the
blood,
digestive
tract,
kidneys,
and
central
nervous
system),
and
acute
health
disorders
(
e.
g.,
lung
irritation
and
congestion,
alimentary
effects
such
as
nausea
and
vomiting,
and
effects
on
the
central
nervous
system).
Provided
below
are
brief
descriptions
of
risks
associated
with
HAP
that
are
emitted
from
hazardous
waste
combustors.
Antimony
Antimony
occurs
at
very
low
levels
in
the
environment,
both
in
the
soils
and
foods.
Higher
concentrations,
however,
are
found
at
antimony
processing
sites,
and
in
their
hazardous
wastes.
The
most
common
industrial
use
of
antimony
is
as
a
fire
retardant
in
the
form
of
antimony
trioxide.
Chronic
occupational
exposure
to
antimony
(
generally
antimony
trioxide)
is
most
commonly
associated
with
"
antimony
pneumoconiosis,"
a
condition
involving
fibrosis
and
scarring
of
the
lung
tissues.
Studies
have
shown
that
antimony
accumulates
in
the
lung
and
is
retained
for
long
periods
of
time.
Effects
are
not
limited
to
the
lungs,
however,
and
myocardial
effects
(
effects
on
the
heart
muscle)
and
related
effects
(
e.
g.,
increased
blood
pressure,
altered
EKG
readings)
are
among
the
best­
characterized
human
health
effects
associated
with
antimony
exposure.
Reproductive
effects
(
increased
incidence
of
spontaneous
abortions
and
higher
rates
of
premature
deliveries)
have
been
observed
in
female
workers
exposed
in
an
antimony
processing
facilities.
Similar
effects
on
the
heart,
lungs,
and
reproductive
system
have
been
observed
in
laboratory
animals.
EPA
assessed
the
carcinogenicity
of
antimony
and
found
the
evidence
for
carcinogenicity
to
be
weak,
with
conflicting
evidence
from
inhalation
studies
with
laboratory
animals,
equivocal
data
from
the
occupational
studies,
negative
results
from
studies
of
oral
exposures
in
laboratory
animals,
and
little
evidence
of
mutagenicity
or
genotoxicity.
4
As
a
4
See
"
Evaluating
the
Carcinogenicity
of
Antimony,"
Risk
Assessment
Issue
Paper
(
98­
030/
07­
26­
99),
Superfund
Technical
Support
Center,
National
Center
for
Environmental
Assessment,
July
26,
1999.
consequence,
EPA
concluded
that
insufficient
data
are
available
to
adequately
characterize
the
carcinogenicity
of
antimony
and,
accordingly,
the
carcinogenicity
of
antimony
cannot
be
determined
based
on
available
information.
However,
the
International
Agency
for
Research
on
Cancer
in
an
earlier
evaluation,
concluded
that
antimony
trioxide
is
"
possibly
carcinogenic
to
humans"
(
Group
2B).
Arsenic
Chronic
(
long­
term)
inhalation
exposure
to
inorganic
arsenic
in
humans
is
associated
with
irritation
of
the
skin
and
mucous
membranes.
Human
data
suggest
a
relationship
between
inhalation
exposure
of
women
working
at
or
living
near
metal
smelters
and
an
increased
risk
of
reproductive
effects,
such
as
spontaneous
abortions.
Inorganic
arsenic
exposure
in
humans
by
the
inhalation
route
has
been
shown
to
be
strongly
associated
with
lung
cancer,
while
ingestion
or
inorganic
arsenic
in
humans
has
been
linked
to
a
form
of
skin
cancer
and
also
to
bladder,
liver,
and
lung
cancer.
EPA
has
classified
inorganic
arsenic
as
a
Group
A,
human
carcinogen.
Beryllium
Chronic
inhalation
exposure
of
humans
to
high
levels
of
beryllium
has
been
reported
to
cause
chronic
beryllium
disease
(
berylliosis),
in
which
granulomatous
(
noncancerous)
lesions
develop
in
the
lung.
Inhalation
exposure
to
high
levels
of
beryllium
has
been
demonstrated
to
cause
lung
cancer
in
rats
and
monkeys.
Human
studies
are
limited,
but
suggest
a
causal
relationship
between
beryllium
exposure
and
an
increased
risk
of
lung
cancer.
We
have
classified
beryllium
as
a
Group
B1,
probable
human
carcinogen,
when
inhaled;
data
are
inadequate
to
determine
whether
beryllium
is
carcinogenic
when
ingested.
Cadmium
Chronic
inhalation
or
oral
exposure
to
cadmium
leads
to
a
build­
up
of
cadmium
in
the
kidneys
that
can
cause
kidney
disease.
Cadmium
has
been
shown
to
be
a
developmental
toxicant
in
animals,
resulting
in
fetal
malformations
and
other
effects,
but
no
conclusive
evidence
exists
in
humans.
An
association
between
cadmium
exposure
and
an
increased
risk
of
lung
cancer
has
been
reported
from
human
studies,
but
these
studies
are
inconclusive
due
to
confounding
factors.
Animal
studies
have
demonstrated
an
increase
in
lung
cancer
from
long­
term
inhalation
exposure
to
cadmium.
EPA
has
classified
cadmium
as
a
Group
B1,
probable
carcinogen.
Chlorine
gas
Chlorine
is
an
irritant
to
the
eyes,
the
upper
respiratory
tract,
and
lungs.
Chronic
exposure
to
chlorine
gas
in
workers
has
resulted
in
respiratory
effects
including
eye
and
throat
irritation
and
airflow
obstruction.
No
information
is
available
on
the
carcinogenic
effects
of
chlorine
in
humans
from
inhalation
exposure.
A
National
Toxicology
Program
(
NTP)
study
showed
no
evidence
of
carcinogenic
activity
in
male
rats
or
male
and
female
mice,
and
equivocal
evidence
in
female
rats,
from
ingestion
of
chlorinated
water.
The
EPA
has
not
classified
chlorine
for
potential
carcinogenicity.
In
the
absence
of
specific
scientific
evidence
to
the
contrary,
it
is
the
Agency's
policy
to
classify
noncarcinogenic
effects
as
threshold
effects.
RfC
development
is
the
default
approach
for
threshold
(
or
nonlinear)
effects.
Chromium
Chromium
may
be
emitted
in
two
forms,
trivalent
chromium
(
chromium
III)
or
hexavalent
chromium
(
chromium
VI).
The
respiratory
tract
is
the
major
target
organ
for
chromium
VI
toxicity
for
inhalation
exposures.
Bronchitis,
decreases
pulmonary
function,
pneumonia,
and
other
respiratory
effects
have
been
noted
from
chronic
high
does
exposure
in
occupational
settings
due
to
chromium
VI.
Limited
human
studies
suggest
that
chromium
VI
inhalation
exposure
may
be
associated
with
complications
during
pregnancy
and
childbirth,
while
animal
studies
have
not
reported
reproductive
effects
from
inhalation
exposure
to
chromium
VI.
Human
and
animal
studies
have
clearly
established
that
inhaled
chromium
VI
is
a
carcinogen,
resulting
in
an
increased
risk
of
lung
cancer.
EPA
has
classified
chromium
VI
as
a
Group
A,
human
carcinogen.
Chromium
III
is
less
toxic
than
chromium
VI.
The
respiratory
tract
is
also
the
major
target
organ
for
chromium
III
toxicity,
similar
to
chromium
VI.
Chromium
III
is
an
essential
element
in
humans,
with
a
daily
intake
of
50
to
200
micrograms
per
day
recommended
for
an
adult.
The
body
can
detoxify
some
amount
of
chromium
VI
to
chromium
III.
EPA
has
not
classified
chromium
III
with
respect
to
carcinogenicity.
Cobalt
Cobalt
is
a
relatively
rare
metal
that
is
produced
primarily
as
a
by­
product
during
refining
of
other
metals,
especially
copper.
Cobalt
has
been
widely
reported
to
cause
respiratory
effects
in
humans
exposed
by
inhalation,
including
respiratory
irritation,
wheezing,
asthma,
and
pneumonia.
Cardiomyopathy
(
damage
to
the
heart
muscle)
has
also
been
reported,
although
this
effect
is
better
known
from
oral
exposure.
Other
effects
of
oral
exposure
in
humans
are
polycythemia
(
an
abnormally
high
number
of
red
blood
cells)
and
the
blocking
of
uptake
of
iodine
by
the
thyroid.
In
addition,
cobalt
is
a
sensitizer
in
humans
by
any
route
of
exposure.
Sensitized
individuals
may
react
to
inhalation
of
cobalt
by
developing
asthma
or
to
ingestion
or
dermal
contact
with
cobalt
by
developing
dermatitis.
Cobalt
is
as
a
vital
component
of
vitamin
B12,
though
there
is
no
evidence
that
intake
of
cobalt
is
ever
limiting
in
the
human
diet.
A
number
of
epidemiological
studies
have
found
that
exposures
to
cobalt
are
associated
with
an
increased
incidence
of
lung
cancer
in
occupational
settings.
The
International
Agency
for
Research
on
Cancer
(
part
of
the
World
Health
Organization)
classifies
cobalt
and
cobalt
compounds
as
"
possibly
carcinogenic
to
humans"
(
Group
2B).
The
American
Conference
of
Governmental
Industrial
Hygienists
has
classified
cobalt
as
a
confirmed
animal
carcinogen
with
unknown
relevance
to
humans
(
category
A3).
An
EPA
assessment
concludes
that
under
EPA's
cancer
guidelines,
cobalt
would
be
considered
likely
to
be
carcinogenic
to
humans.
5
Dioxins
and
Furans
Exposures
to
2,3,7,8­
tetrachlorodibenzo­
p­
dioxin
(
2,3,7,8­
TCDD)
and
related
compounds
at
levels
10
times
or
less
above
those
modeled
to
approximate
average
background
exposure
have
resulted
in
adverse
non­
cancer
health
effects
in
animals.
This
statement
is
based
on
assumptions
about
the
toxic
equivalent
for
these
compounds,
for
which
there
is
acknowledged
uncertainty.
These
effects
include
changes
in
hormone
systems,
alterations
in
fetal
development,
reduced
reproductive
capacity,
and
immunosuppression.
Effects
that
may
be
linked
to
dioxin
and
furan
exposures
at
low
dose
in
humans
include
changes
in
markers
of
early
development
and
hormone
levels.
Dioxin
and
furan
exposures
5
See
"
Derivation
of
a
Provisional
Carcinogenicity
Assessment
for
Cobalt
and
Compounds,"
Risk
Assessment
Issue
Paper
(
00­
122/
1­
15­
02),
Superfund
Technical
Support
Center,
National
Center
for
Environmental
Assessment,
January
15,
2002.
This
is
a
provisional
EPA
assessment
that
has
been
externally
peer
reviewed
but
has
not
yet
been
incorporated
in
IRIS.
are
associated
with
altered
liver
function
and
lipid
metabolism
changes
in
activity
of
various
liver
enzymes,
depression
of
the
immune
system,
and
endocrine
and
nervous
system
effects.
EPA
in
its
1985
dioxin
assessment
classified
2,3,7,8­
TCDD
as
a
probable
human
carcinogen.
The
International
Agency
for
Research
on
Cancer
(
IARC)
concluded
in
1997
that
the
overall
weight
of
the
evidence
was
sufficient
to
characterize
2,3,7,8­
TCDD
as
a
known
human
carcinogen.
6
In
2001
the
U.
S.
Department
of
Health
and
Human
Services
National
Toxicology
Program
in
their
9th
Report
on
Carcinogens
classified
2,3,7,8­
TCDD
as
a
known
human
carcinogen.
7
The
chemical
and
environmental
stability
of
dioxins
and
their
tendency
to
accumulate
in
fat
have
resulted
in
their
detection
within
many
ecosystems.
In
the
United
States
and
elsewhere,
accidental
contamination
of
the
environment
by
2,3,7,8­
TCDD
has
resulted
in
deaths
in
many
species
of
wildlife
and
domestic
animals.
8
High
residues
of
this
compound
in
fish
have
resulted
in
closing
rivers
to
fishing.
Laboratory
studies
with
birds,
mammals,
aquatic
organisms,
and
other
species
have
demonstrated
that
exposure
to
2,3,7,8­
TCDD
can
result
in
acute
and
delayed
mortality
as
well
as
carcinogenic,
teratogenic,
mutagenic,
histopathologic,
immunotoxic,
and
reproductive
effects,
depending
on
dose
received,
which
varied
widely
in
the
experiments.
9
Hydrogen
chloride/
hydrochloric
acid
Hydrogen
chloride,
also
called
hydrochloric
acid,
is
corrosive
to
the
eyes,
skin,
and
mucous
membranes.
Chronic
(
long­
term)
occupational
exposure
to
hydrochloric
acid
has
been
reported
to
cause
gastritis,
bronchitis,
and
dermatitis
in
workers.
Prolonged
exposure
to
low
concentrations
may
also
cause
dental
discoloration
and
erosion.
No
information
is
available
on
the
reproductive
or
developmental
effects
of
hydrochloric
acid
in
humans.
In
rats
exposed
to
hydrochloric
acid
by
inhalation,
altered
estrus
cycles
have
been
reported
in
females
and
increased
fetal
mortality
and
decreased
fetal
weight
have
been
reported
in
offspring.
EPA
has
not
classified
hydrochloric
acid
for
carcinogenicity.
In
the
absence
of
specific
scientific
evidence
to
the
contrary,
it
is
the
Agency's
policy
to
classify
noncarcinogenic
effects
as
threshold
effects.
RfC
development
is
the
default
approach
for
threshold
(
or
nonlinear)
effects.
Lead
Lead
can
cause
a
variety
of
effects
at
low
dose
levels.
Chronic
exposure
to
high
levels
of
lead
in
humans
results
in
effects
on
the
blood,
central
nervous
system,
blood
pressure,
and
kidneys.
Children
are
particularly
sensitive
to
the
chronic
effects
of
lead,
with
slowed
cognitive
development,
reduced
growth
and
other
effects
reported.
Reproductive
effects,
such
as
decreased
sperm
count
in
men
and
spontaneous
abortions
in
women,
have
6
IARC
(
International
Agency
for
Research
on
Cancer).
(
1997)
IARC
monographs
on
the
evaluation
of
carcinogenic
risks
to
humans.
Vol.
69.
Polychlorinated
dibenzo­
para­
dioxins
and
polychlorinated
dibenzofurans.
Lyon,
France.

7
The
U.
S.
Department
of
Health
and
Human
Services,
National
Toxicology
Program
9th
Report
on
Carcinogens,
Revised
January
2001.

8
This
does
not
necessarily
apply
in
regard
to
laboratory
testing,
which
tend
to
use
2,3,7,8
TCDD
as
the
test
compound.
9
been
associated
with
lead
exposure.
The
developing
fetus
is
at
particular
risk
from
maternal
lead
exposure,
with
low
birth
weight
and
slowed
postnatal
neurobehavioral
development
noted.
Human
studies
are
inconclusive
regarding
lead
exposure
and
cancer,
while
animal
studies
have
reported
an
increase
in
kidney
cancer
from
lead
exposure
by
the
oral
route.
EPA
has
classified
lead
as
a
Group
B2,
probable
human
carcinogen.
Manganese
Health
effects
in
humans
have
been
associated
with
both
deficiencies
and
excess
intakes
of
manganese.
Chronic
exposure
to
low
levels
of
manganese
in
the
diet
is
considered
to
be
nutritionally
essential
in
humans,
with
a
recommended
daily
allowance
of
2
to
5
milligrams
per
day
(
mg/
d).
Chronic
exposure
to
high
levels
of
manganese
by
inhalation
in
humans
results
primarily
in
central
nervous
system
effects.
Visual
reaction
time,
hand
steadiness,
and
eye­
hand
coordination
were
affected
in
chronically­
exposed
workers.
Impotence
and
loss
of
libido
have
been
noted
in
male
workers
afflicted
with
manganism
attributed
to
inhalation
exposures.
EPA
has
classified
manganese
in
Group
D,
not
classifiable
as
to
carcinogenicity
in
humans.
Mercury
Mercury
exists
in
three
forms:
elemental
mercury,
inorganic
mercury
compounds
(
primarily
mercuric
chloride),
and
organic
mercury
compounds
(
primarily
methyl
mercury).
Each
form
exhibits
different
health
effects.
Various
sources
may
release
elemental
or
inorganic
mercury;
environmental
methyl
mercury
is
typically
formed
by
biological
processes
after
mercury
has
precipitated
from
the
air.
Chronic
exposure
to
elemental
mercury
in
humans
also
affects
the
central
nervous
system,
with
effects
such
as
increased
excitability,
irritability,
excessive
shyness,
and
tremors.
The
EPA
has
not
classified
elemental
mercury
with
respect
to
cancer.
The
major
effect
from
chronic
exposure
to
inorganic
mercury
is
kidney
damage.
Reproductive
and
developmental
animal
studies
have
reported
effects
such
as
alterations
in
testicular
tissue,
increased
embryo
resorption
rates,
and
abnormalities
of
development.
Mercuric
chloride
(
an
inorganic
mercury
compound)
exposure
has
been
shown
to
result
in
forestomach,
thyroid,
and
renal
tumors
in
experimental
animals.
EPA
has
classified
mercuric
chloride
as
a
Group
C,
possible
human
carcinogen.
Nickel
Nickel
is
an
essential
element
in
some
animal
species,
and
it
has
been
suggested
it
may
be
essential
for
human
nutrition.
Nickel
dermatitis,
consisting
of
itching
of
the
fingers,
hand
and
forearms,
is
the
most
common
effect
in
humans
from
chronic
exposure
to
nickel.
Respiratory
effects
have
also
been
reported
in
humans
from
inhalation
exposure
to
nickel.
No
information
is
available
regarding
the
reproductive
of
developmental
effects
of
nickel
in
humans,
but
animal
studies
have
reported
such
effects,
although
a
consistent
dose­
response
relationship
has
not
been
seen.
Nickel
forms
released
from
industrial
boilers
include
soluble
nickel
compounds,
nickel
subsulfide,
and
nickel
carbonyl.
Human
and
animal
studies
have
reported
an
increased
risk
of
lung
and
nasal
cancers
from
exposure
to
nickel
refinery
dusts
and
nickel
subsulfide.
Animal
studies
of
soluble
nickel
compounds
(
i.
e.,
nickel
carbonyl)
have
reported
lung
tumors.
The
EPA
has
classified
nickel
refinery
subsulfide
as
a
Group
A,
human
carcinogen
and
nickel
carbonyl
as
a
Group
B2,
probable
human
carcinogen.
Organic
HAP
Organic
HAPs
include
halogenated
and
nonhalogenated
organic
classes
of
compounds
such
as
polycyclic
aromatic
hydrocarbons
(
PAHs)
and
polychlorinated
biphenyls
(
PCBs).
Both
PAHs
and
PCBs
are
classified
as
potential
human
carcinogens,
and
are
considered
toxic,
persistent
and
bioaccumulative.
Organic
HAP
also
include
compounds
such
as
benzene,
methane,
propane,
chlorinated
alkanes
and
alkenes,
phenols
and
chlorinated
aromatics.
Adverse
health
effects
of
HAPs
include
damage
to
the
immune
system,
as
well
as
neurological,
reproductive,
developmental,
respiratory
and
other
health
problems.
Particulate
Matter
Atmospheric
particulate
matter
(
PM)
is
composed
of
sulfate,
nitrate,
ammonium,
and
other
ions,
elemental
carbon,
particle­
bound
water,
a
wide
variety
of
organic
compounds,
and
a
large
number
of
elements
contained
in
various
compounds,
some
of
which
originate
from
crustal
materials
and
others
from
combustion
sources.
Combustion
sources
are
the
primary
origin
of
trace
metals
found
in
fine
particles
in
the
atmosphere.
Ambient
PM
can
be
of
primary
or
secondary
origin.
Exposure
to
particles
can
lead
to
a
variety
of
serious
health
effects.
The
largest
particles
do
not
get
very
far
into
the
lungs,
so
they
tend
to
cause
fewer
harmful
health
effects.
Fine
particles
pose
the
greatest
problems
because
they
can
get
deep
into
the
lungs.
Scientific
studies
show
links
between
these
small
particles
and
numerous
adverse
health
effects.
Epidemiological
studies
have
shown
a
significant
correlation
between
elevated
PM
levels
and
premature
mortality.
Other
important
effects
associated
with
PM
exposure
include
aggravation
of
respiratory
and
cardiovascular
disease
(
as
indicated
by
increased
hospital
admissions,
emergency
room
visits,
absences
from
school
or
work,
and
restricted
activity
days),
lung
disease,
decreased
lung
function,
asthma
attacks,
and
certain
cardiovascular
problems.
Individuals
particularly
sensitive
to
PM
exposure
include
older
adults
and
people
with
heart
and
lung
disease.
This
is
only
a
partial
summary
of
adverse
health
and
environmental
effects
associated
with
exposure
to
PM.
Further
information
is
found
in
the
2004
Criteria
Document
for
PM
("
Air
Quality
Criteria
for
Particulate
Matter,"
EPA/
600/
P­
99/
002bF)
and
the
2005
Staff
Paper
for
PM
(
EPA,
"
Review
of
the
National
Ambient
Air
Quality
Standards
for
Particulate
Matter,
Policy
Assessment
of
Scientific
and
Technical
Information:
OAQPS
Staff
Paper,"
(
June
2005)).
Selenium
Selenium
is
a
naturally
occurring
substance
that
is
toxic
at
high
concentrations
but
is
also
a
nutritionally
essential
element.
Studies
of
humans
chronically
exposed
to
high
levels
of
selenium
in
food
and
water
have
reported
discoloration
of
the
skin,
pathological
deformation
and
loss
of
nails,
loss
of
hair,
excessive
tooth
decay
and
discoloration,
lack
of
mental
alertness,
and
listlessness.
The
consumption
of
high
levels
of
selenium
by
pigs,
sheep,
and
cattle
has
been
shown
to
interfere
with
normal
fetal
development
and
to
produce
birth
defects.
Results
of
human
and
animal
studies
suggest
that
supplementation
with
some
forms
of
selenium
may
result
in
a
reduced
incidence
of
several
tumor
types.
One
selenium
compound,
selenium
sulfide,
is
carcinogenic
in
animals
exposed
orally.
We
have
classified
elemental
selenium
as
a
Group
D,
not
classifiable
as
to
human
carcinogenicity,
and
selenium
sulfide
as
a
Group
B2,
probable
human
carcinogen.

Part
Two:
Summary
of
the
Final
Rule
I.
What
Source
Categories
and
Subcategories
Are
Affected
by
the
Final
Rule?

Today's
rule
promulgates
standards
for
controlling
emissions
of
HAP
from
hazardous
waste
combustors:
incinerators,
cement
kilns,
lightweight
aggregate
kilns,
boilers,
and
hydrochloric
acid
production
furnaces
that
burn
hazardous
waste.
A
description
of
each
source
category
can
be
found
in
the
proposed
rule
(
see
69
FR
at
21207­
08).
Hazardous
waste
burning
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
are
currently
subject
to
40
CFR
part
63,
subpart
EEE,
National
Emission
Standards
for
Hazardous
Air
Pollutants
(
NESHAP).
Today's
rule
revises
the
emissions
limits
and
certain
compliance
and
monitoring
provisions
of
subpart
EEE
for
these
source
categories.
The
definitions
of
hazardous
waste
incinerator,
hazardous
waste
cement
kiln,
and
hazardous
waste
lightweight
aggregate
kiln
appear
at
40
CFR
63.1201(
a).
Boilers
that
burn
hazardous
waste
are
also
affected
sources
under
today's
rule.
The
rule
uses
the
RCRA
definition
of
a
boiler
under
40
CFR
260.10
and
includes
industrial,
commercial,
and
institutional
boilers
as
well
as
thermal
units
known
as
process
heaters.
Hazardous
waste
burning
boilers
will
continue
to
comply
with
the
emission
standards
found
under
40
CFR
part
266,
subpart
H
(
i.
e.,
the
existing
RCRA
rules)
until
they
demonstrate
compliance
with
the
requirements
of
40
CFR
part
63,
subpart
EEE,
and,
for
permitted
sources,
subsequently
remove
these
requirements
from
their
RCRA
permit.
Finally,
hydrochloric
acid
production
furnaces
that
burn
hazardous
waste
are
affected
sources
under
today's
rule.
These
furnaces
are
a
type
of
halogen
acid
furnace
included
in
the
definition
of
"
industrial
furnace"
defined
at
§
260.10.
Hydrochloric
acid
production
furnaces
that
burn
hazardous
waste
will
continue
to
comply
with
the
emission
standards
found
under
40
CFR
part
266,
subpart
H,
until
they
demonstrate
compliance
with
40
CFR
part
63,
subpart
EEE,
and,
for
permitted
sources,
subsequently
remove
these
requirements
from
their
RCRA
permit.

II.
What
Are
the
Affected
Sources
and
Emission
Points?

Today's
rule
apply
to
each
major
and
area
source
incinerator,
cement
kiln,
lightweight
aggregate
kiln,
boiler,
and
hydrochloric
acid
production
furnace
that
burns
hazardous
waste.
10
We
note
that
only
major
source
boilers
and
hydrochloric
acid
production
furnaces
are
subject
to
the
full
suite
of
subpart
EEE
emission
standards.
11
The
emissions
limits
apply
to
each
emission
point
(
e.
g.,
stack)
where
gases
from
the
combustion
of
hazardous
waste
are
discharged
or
otherwise
emitted
into
the
atmosphere.
For
facilities
that
have
multiple
combustion
gas
discharge
points,
the
emission
limits
generally
apply
to
each
emission
point.
A
cement
kiln,
for
example,
could
be
configured
to
have
dual
stacks
where
the
majority
of
combustion
gases
are
discharged
though
the
main
stack
and
other
combustion
gases
emitted
through
a
separate
stack,
such
as
an
alkali
bypass
stack.
In
that
case,
the
emission
standards
would
apply
separately
to
each
of
these
stacks.
12
III.
What
Pollutants
Are
Emitted
and
Controlled?

Hazardous
waste
combustors
emit
dioxin/
furans,
sometimes
at
high
levels
depending
on
the
design
and
operation
of
the
emission
control
equipment,
and,
for
incinerators,

10
A
major
source
emits
or
has
the
potential
to
emit
10
tons
per
year
of
any
single
hazardous
air
pollutant
or
25
tons
per
year
or
greater
of
hazardous
air
pollutants
in
the
aggregate.
An
area
source
is
a
source
that
is
not
a
major
source.
11
See
Part
Four,
Section
II.
A
for
a
discussion
of
the
standards
that
are
applicable
to
area
source
boilers
and
hydrochloric
acid
production
furnaces.
12
We
note
that
there
is
a
provision
that
allows
cement
kilns
with
dual
stacks
to
average
emissions
on
a
flow­
weighted
basis
to
demonstrate
compliance
with
the
metal
and
chlorine
emission
standards.
See
§
§
63.1204(
e)
and
63.1220(
e).
depending
on
whether
a
waste
heat
recovery
boiler
is
used.
All
hazardous
waste
combustors
can
also
emit
high
levels
of
other
organic
HAP
if
they
are
not
designed,
operated,
and
maintained
to
operate
under
good
combustion
conditions.
Hazardous
waste
combustors
can
also
emit
high
levels
of
metal
HAP,
depending
on
the
level
of
metals
in
the
waste
feed
and
the
design
and
operation
of
air
emissions
control
equipment.
Hazardous
waste
burning
hydrochloric
acid
production
furnaces,
however,
generally
feed
and
emit
low
levels
of
metal
HAP.
All
of
these
HAP
metals
(
except
for
the
volatile
metal
mercury)
are
emitted
as
a
portion
of
the
particulate
matter
emitted
by
these
sources.
Hazardous
waste
combustors
can
also
emit
high
levels
of
particulate
matter,
except
that
hydrochloric
acid
production
furnaces
generally
feed
hazardous
wastes
with
low
ash
content
and
consequently
emit
low
levels
of
particulate
matter.
A
majority
of
particulate
matter
emissions
from
hazardous
waste
combustors
are
in
the
form
of
fine
particulate.
Particulate
emissions
from
incinerators
and
liquid
fuel­
fired
boilers
depend
on
the
ash
content
of
the
hazardous
waste
feed
and
the
design
and
operation
of
air
emission
control
equipment.
Particulate
emissions
from
cement
kilns
and
lightweight
aggregate
kilns
are
not
significantly
affected
by
the
ash
content
of
the
hazardous
waste
fuel
because
uncontrolled
particulate
emissions
are
attributable
primarily
to
fine
raw
material
entrained
in
the
combustion
gas.
Thus,
particulate
emissions
from
kilns
depends
on
operating
conditions
that
effect
entrainment
of
raw
material,
and
the
design
and
operation
of
the
emission
control
equipment.

IV.
Does
the
Final
Rule
Apply
to
Me?

The
final
rule
applies
to
you
if
you
own
or
operate
a
hazardous
waste
combustor
 
an
incinerator,
cement
kiln,
lightweight
aggregate
kiln,
boiler,
or
hydrochloric
acid
production
facility
that
burns
hazardous
waste.
The
final
rule
does
not
apply
to
a
source
that
meets
the
applicability
requirements
of
§
63.1200(
b)
for
reasons
explained
at
69
FR
at
21212­
13.

V.
What
Are
the
Emission
Limitations?

You
must
meet
the
emission
limits
in
Tables
1
and
2
of
this
preamble
for
your
applicable
source
category
and
subcategory.
Standards
are
corrected
to
7
percent
oxygen.
As
noted
at
proposal,
we
previously
promulgated
requirements
for
carbon
monoxide,
total
hydrocarbon,
and
destruction
and
removal
efficiency
standards
under
subpart
EEE
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
We
view
these
standards
as
unaffected
by
the
Court's
vacature
of
the
challenged
regulations
in
its
decision
of
July
24,
2001.
We
are
therefore
not
re­
promulgating
and
reopening
consideration
of
these
standards
in
today's
final
rule,
but
are
summarizing
these
standards
in
Tables
1
and
2
for
reader's
convenience.
13
See
69
FR
at
21221,
21248,
21261
and
21274.
Liquid
fuel
boilers
equipped
with
dry
air
pollution
control
devices
are
subject
to
different
dioxin/
furan
emission
standards
than
liquid
fuel
boilers
that
are
not
equipped
with
dry
air
pollution
control
devices.
14
Liquid
fuel
boilers
processing
hazardous
waste
with
a
heating
value
less
than
10,000
BTU/
lb
must
comply
with
the
emission
concentration­
based
standards
(
expressed
as
mass
of
total
HAP
emissions
per
volume
of
stack
gas
emitted)
for
13
We
are
also
republishing
these
standards,
for
reader's
convenience
only,
in
the
new
replacement
standard
section
for
these
source
categories.
See
§
63.1219,
§
63.1220
and
§
63.1219.
14
Liquid
fuel
boilers
equipped
with
a
wet
air
pollution
control
device
followed
by
a
dry
air
pollution
control
device
do
not
meet
the
definition
of
a
dry
air
pollution
device.
mercury,
semivolatile
metals,
low
volatile
metals,
and
total
chlorine.
Liquid
fuel
boilers
processing
hazardous
waste
with
heating
values
greater
than
10,000
BTU/
lb
must
comply
with
thermal
emissions­
based
standards
(
expressed
as
mass
of
HAP
emissions
attributable
to
the
hazardous
waste
per
million
BTU
input
from
the
hazardous
waste)
for
those
same
pollutants.
Low
volatile
metal
standards
for
liquid
fuel
boilers
apply
only
to
emissions
of
chromium,
whereas
the
low
volatile
metal
standard
for
the
other
source
categories
applies
to
the
combined
emissions
of
chromium,
arsenic,
and
beryllium.
Semivolatile
metal
standards
apply
to
the
combined
emissions
of
lead
and
cadmium.
For
any
of
the
source
categories
except
hydrochloric
acid
production
furnaces,
you
may
elect
to
comply
with
an
alternative
to
the
total
chlorine
standard
under
which
you
would
establish
site­
specific,
health­
based
emission
limits
for
hydrogen
chloride
and
chlorine
based
on
national
exposure
standards.
This
alternative
chlorine
standard
is
discussed
in
part
two,
section
IX
and
part
four,
section
VII.
Incinerators
and
liquid
and
solid
fuel
boilers
may
elect
to
comply
with
an
alternative
to
the
particulate
matter
standard
that
would
limit
emissions
of
all
the
semivolatile
metal
HAPs
and
low
volatile
metal
HAPs.
Under
this
alternative,
the
numerical
emission
limits
for
semivolatile
metal
and
low
volatile
metal
emission
HAP
are
identical
to
the
limitations
included
in
Tables
1
and
2.
However,
for
semivolatile
metals,
the
alternative
standard
applies
to
the
combined
emissions
of
lead,
cadmium,
and
selenium;
for
low
volatile
metals,
the
standard
applies
to
the
combined
emissions
of
chromium,
arsenic,
beryllium,
antimony,
cobalt,
manganese,
and
nickel.
See
§
63.1219(
e).
Table
1.
Summary
of
Emission
Limits
for
Existing
Sources
Incinerators
Cement
Kilns
Lightweight
Aggregate
Kilns
Solid
Fuel­
Fired
Boilers1
Liquid
Fuel­
Fired
Boilers1
Hydrochloric
Acid
Production
Furnaces1
Dioxin/
Furans
(
ng
TEQ/
dscm)
0.20
or
0.40
and
temperature
control
<
400
°
F
at
APCD
inlet6
0.20
or
0.40
and
temperature
control
<
400
°
F
at
APCD
inlet
0.20
or
rapid
quench
below
400
°
F
at
kiln
exit
CO
or
HC
and
DRE
standard
as
a
surrogate
0.40
for
dry
APCD
sources;
CO
or
HC
and
DRE
standard
as
surrogate
for
others
CO
or
HC
and
DRE
standard
as
surrogate
Mercury
130
ug/
dscm
Hazardous
waste
feed
restriction
of
3.0
ppmw
and
120
ug/
dscm
MTEC11;
or
120
ug/
dscm
total
emissions
120
hazardous
waste
MTEC11
feed
restriction
or
120
ug/
dscm
total
emissions
11
ug/
dscm
4.2E­
5lb/
MMBtu2,5
or
19
ug/
dscm2;
depending
on
BTU
content
of
hazardous
waste13
Total
chlorine
standard
as
surrogate
Particulate
Matter
0.013
gr/
dscf
8
0.028
gr/
dscf
and
20%
opacity12
0.025
gr/
dscf
0.030
gr/
dscf
8
0.035
gr/
dscf
8
Total
chlorine
standard
as
surrogate
Semivolatile
Metals
(
lead
+
cadmium)
230
ug/
dscm
7.6
E­
4
lbs/
MMBtu5
and
330
ug/
dscm3
3.0E­
4
lb/
MMBtu5
and
250
ug/
dscm3
180
ug/
dscm
8.2
E­
5
lb/
MMBtu2,5
or
150
ug/
dscm2;
depending
on
BTU
content
of
hazardous
waste13
Total
chlorine
standard
as
surrogate
Low
Volatile
Metals
(
arsenic
+
beryllium
+
chromium)
92
ug/
dscm
2.1
E­
5
lbs/
MMBtu5
and
56
ug/
dscm3
9.5E­
5
lb/
MMBtu5
and
110
ug/
dscm3
380
ug/
dscm
1.26E­
4
lbMMBtu4,5
or
370
ug/
dscm4;
depending
on
BTU
content
of
hazardous
waste13
Total
chlorine
standard
as
surrogate
Total
Chlorine
(
hydrogen
chloride
+
chlorine
gas)
32
ppmv7
120
ppmv7
600
ppmv7
440
ppmv7
5.08E­
2
lb/
MMBtu5,7
or
31
ppmv7;
depending
on
BTU
content
of
hazardous
waste13
150
ppmv
or
99.923%
system
removal
efficiency
Carbon
Monoxide
(
CO)
or
Hydrocarbons
(
HC)
100
ppmv
CO9
or
10
ppmv
HC
See
Note
#
10
below
100
ppmv
CO9
or
20
ppmv
HC
100
ppmv
CO9
or
10
ppmv
HC
Destruction
and
Removal
Efficiency
99.99%
for
each
principal
organic
hazardous
pollutant.
For
sources
burning
hazardous
wastes
F020,
F021,
F022,
F023,
F026,
or
F027,
however,
99.9999%
for
each
principal
organic
hazardous
pollutant.

Notes:
1
Particulate
matter,
semivolatile
metal,
low
volatile
metal,
and
total
chlorine
standards
for
solid
and
liquid
fuel
boilers
apply
only
to
major
sources.
Particulate
matter,
semivolatile
and
low
volatile
metal
standards
for
hydrochloric
acid
production
furnaces
apply
only
to
major
sources,
although
area
sources
must
still
comply
with
the
surrogate
total
chlorine
standard
to
control
mercury
emissions.
2
Standard
is
based
on
normal
emissions
data,
and
is
therefore
expressed
as
an
annual
average
emission
limitation.
3
Sources
must
comply
with
both
the
thermal
emissions
and
emission
concentration
standards.
4
Low
volatile
metal
standard
for
liquid
fuel­
fired
boilers
is
for
chromium
only.
5
Standards
expressed
as
mass
of
pollutant
contributed
by
hazardous
waste
per
million
BTU
contributed
by
the
hazardous
waste.
6
APCD
means
"
air
pollution
control
device".
7
Sources
may
elect
to
comply
with
site­
specific
risk­
based
emission
limits
for
hydrogen
chloride
and
chlorine
gas
8
Sources
may
elect
to
comply
with
an
alternative
to
the
particulate
matter
standard.
9
Sources
that
elect
to
comply
with
the
CO
standard
must
demonstrate
compliance
with
the
HC
standard
during
the
comprehensive
performance
test
that
demonstrates
compliance
with
the
destruction
and
removal
efficiency
requirement.
10
Kilns
without
a
bypass:
20
ppmv
HC
or
100
ppmv
CO9
.
Kilns
with
a
bypass/
mid­
kiln
sampling
system:
10
ppmv
HC
or
100
ppmv
CO9
in
the
bypass
duct,
mid­
kiln
sampling
system
or
bypass
stack.
11
MTEC
means
"
maximum
theoretical
emission
concentration",
and
is
equivalent
to
the
feed
rate
divided
by
gas
flow
rate
12
The
opacity
standard
does
not
apply
to
a
source
equipped
with
a
bag
leak
detection
system
under
63.1206(
c)(
8)
or
a
particulate
matter
detection
system
under
63.1206(
c)(
9).
13
Emission
concentration­
based
standards
apply
to
sources
processing
hazardous
waste
with
energy
content
less
than
10,000
BTU/
lb;
thermal
emission
standards
apply
to
sources
processing
hazardous
waste
with
energy
content
greater
than
10,000
btu/
lb.
Table
2.
Summary
of
Emission
Limits
for
New
or
Reconstructed
Sources
Incinerators
Cement
Kilns
Lightweight
Aggregate
Kilns
Solid
Fuel
Boilers
1
Liquid
Fuel
Boilers
1
Hydrochloric
Acid
Production
Furnaces1
Dioxin/
Furans
(
ng
TEQ/
dscm)
0.11
for
dry
APCD
and/
or
WHB5
sources;
0.20
for
other
sources
0.20
or
0.40
and
temperature
control
<
400
°
F
at
APCD
inlet
0.20
or
rapid
quench
<
400
°
F
at
kiln
exit
CO
or
HC
and
DRE
standard
as
a
surrogate
0.40
for
sources
with
dry
APCD;
CO
or
HC
and
DRE
standard
as
a
surrogate
for
other
sources
CO
or
THC
and
DRE
standard
as
a
surrogate
Mercury
8.1
ug/
dscm
Hazardous
waste
feed
restriction
of
1.9
ppmw
and
120
ug/
dscm
MTEC10;
or
120
ug/
dscm
total
emissions
120
hazardous
waste
MTEC10
feed
restriction
or
120
ug/
dscm
total
emissions
11
ug/
dscm
1.2E­
6
lb/
MMBtu2,4
or
6.8
ug/
dscm2;
depending
on
BTU
content
of
hazardous
waste12
TCl
as
surrogate
Particulate
matter
(
gr/
dscf)
0.0015
7
0.0023
and
20%
opacity11
0.0098
0.015
7
0.0087
7
TCl
as
surrogate
Semivolatile
Metals
(
lead
+
cadmium)
10
ug/
dscm
6.2E­
5
lb/
MMBtu4
and
180
ug/
dscm
3.7
E­
5
lb/
MMBtu4
and
43
ug/
dscm
180
ug/
dscm
6.2
E­
6
lb/
MMBtu2,4
or
78
ug/
dscm2;
depending
on
BTU
content
of
hazardous
waste12
TCl
as
surrogate
Low
Volatile
Metals
(
arsenic
+
beryllium
+
chromium)
23
ug/
dscm
1.5E­
5
lb/
MMBtu4
and
54
ug/
dscm
3..
3E­
5
lb/
MMBtu4
and
110
ug/
dscm
190
ug/
dscm
1.41E­
5lb/
MMBtu3,4
or
12
ug/
dscm3;
depending
on
BTU
content
of
hazardous
waste12
TCl
as
surrogate
Total
Chlorine
(
Hydrogen
chloride
+
chlorine
gas)
21
ppmv
6
86
ppmv
6
600
ppmv
6
73
ppmv
6
5.08E­
2
lb/
MMBtu4,6
or
31
ppmv6;
depending
on
BTU
content
of
hazardous
waste12
25
ppmv
or
99.987%
SRE
Carbon
monoxide
(
CO)
or
Hydrocarbons
(
HC)
100
ppmv
CO8
or
10
ppmv
HC
See
note
#
9
below
100
ppmv
CO8
or
20
ppmv
HC
100
ppmv
CO8
or
10
ppmv
HC
Destruction
and
Removal
Efficiency
99.99%
for
each
principal
organic
hazardous
pollutant.
For
sources
burning
hazardous
wastes
F020,
F021,
F022,
F023,
F026,
or
F027,
however,
99.9999%
for
each
principal
organic
hazardous
pollutant.
Notes:
1
Particulate
matter,
semivolatile
metal,
low
volatile
metal,
and
total
chlorine
standards
for
solid
and
liquid
fuel
boilers
apply
only
to
major
sources.
Particulate
matter,
semivolatile
and
low
volatile
metal
standards
for
hydrochloric
acid
production
furnaces
apply
only
to
major
sources,
although
area
sources
must
still
comply
with
the
surrogate
total
chlorine
standard
to
control
mercury
emissions.
2
Standard
is
based
on
normal
emissions
data,
and
is
therefore
expressed
as
an
annual
average
emission
limitation.
3
Low
volatile
metal
standard
for
liquid
fuel­
fired
boilers
is
for
chromium
only.
Arsenic
and
beryllium
are
not
included
in
the
low
volatile
metal
total
for
liquid
fuel­
fired
boilers.
4
Standards
expressed
as
mass
of
pollutant
contributed
by
hazardous
waste
per
million
BTU
contributed
by
the
hazardous
waste.
5
APCD
means
"
air
pollution
control
device",
WHB
means
"
waste
heat
boiler".
6
Sources
may
elect
to
comply
with
risk­
based
emission
limits
for
hydrogen
chloride
and
chlorine
gas
7
Sources
may
elect
to
comply
with
an
alternative
to
the
particulate
matter
standard.
8
Sources
that
elect
to
comply
with
the
CO
standard
must
demonstrate
compliance
with
the
THC
standard
during
the
comprehensive
performance
test
that
demonstrates
compliance
with
the
destruction
and
removal
efficiency
requirement.
9
Greenfield
kilns
without
a
bypass:
20
ppmv
HC
or
100
ppmv
CO8
and
50
ppmv
HC.
Greenfield
kilns
with
a
bypass/
mid
kiln
sampling
system:
Main
stack
standard
of
50
ppmv
HC
and
10
ppmv
HC
or
100
ppmv
CO8
in
the
bypass
duct,
mid­
kiln
sampling
system
or
bypass
stack.
Greenfield
kilns
with
a
bypass/
mid­
kiln
sampling
system:
10
ppmv
HC
or
100
ppmv
CO8
in
the
bypass
duct,
mid­
kiln
sampling
system
or
bypass
stack;
Non­
greenfield
kilns
without
a
bypass:
20
ppmv
HC
or
100
ppmv
CO8.
A
greenfield
kiln
is
a
kiln
whose
construction
commenced
after
April
19,
1996
at
a
plant
site
where
a
cement
kiln
(
whether
burning
hazardous
waste
or
not)
did
not
previously
exist.
10
MTEC
means
"
maximum
theoretical
emission
concentration",
and
is
equivalent
to
the
feed
rate
divided
by
gas
flow
rate.
11
The
opacity
standard
does
not
apply
to
a
source
equipped
with
a
bag
leak
detection
system
under
63.1206(
c)(
8)
or
a
particulate
matter
detection
system
under
63.1206(
c)(
9).
12
Emission
concentration­
based
standards
apply
to
sources
processing
hazardous
waste
with
energy
content
less
than
10,000
BTU/
lb;
thermal
emission
standards
apply
to
sources
processing
hazardous
waste
with
energy
content
greater
than
10,000
btu/
lb.
VI.
What
Are
the
Testing
and
Initial
Compliance
Requirements?

The
testing
and
initial
compliance
requirements
we
promulgate
today
for
solid
fuel
boilers,
liquid
fuel
boilers,
and
hydrochloric
acid
production
furnaces
are
identical
to
those
that
are
applicable
to
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
at
§
§
63.1206,
63.1207,
and
63.1208.
We
note,
however,
that
today's
final
rule
revises
some
of
these
requirements
as
they
apply
to
all
or
specific
HWCs
(
e.
g.,
one­
time
dioxin/
furan
test
for
sources
not
subject
to
a
numerical
dioxin/
furan
standard;
dioxin/
furan
stack
test
method;
hydrogen
chloride
and
chlorine
stack
test
methods)
We
also
discuss
compliance
and
testing
dates
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
as
well.
Even
though
we
are
not
repromulgating
the
compliance
and
testing
requirements
for
those
source
categories,
those
sources
must
demonstrate
compliance
with
the
replacement
emission
standards
promulgated
today.

A.
Compliance
Dates
The
time­
line
for
testing
and
initial
compliance
requirements
is
as
follows:
1.
The
compliance
date
is
[
insert
date
36
months
after
the
date
of
publication]
15;
2.
You
must
submit
a
comprehensive
performance
test
plan
to
the
permitting
authority
for
review
and
approval
12
months
prior
to
commencing
the
test.
3.
You
must
submit
an
eligibility
demonstration
for
the
health­
based
compliance
alternative
to
the
total
chlorine
emission
standard
12
months
before
the
compliance
date
if
you
elect
to
comply
with
§
63.1215;
4.
You
must
place
in
the
operating
record
a
Documentation
of
Compliance
by
the
compliance
date
identifying
the
operating
parameter
limits
that,
using
available
information,
you
have
determined
will
ensure
compliance
with
the
emission
standards;
5.
For
boilers
and
hydrochloric
acid
production
furnaces,
you
must
commence
the
initial
comprehensive
performance
test
within
6
months
after
the
compliance
date;
6.
For
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns,
you
must
commence
the
initial
comprehensive
performance
test
within
12
months
after
the
compliance
date;
7.
You
must
complete
the
initial
comprehensive
performance
test
within
60
days
of
commencing
the
test;
and
8.
You
must
submit
a
Notification
of
Compliance
within
90
days
of
completing
the
test
documenting
compliance
with
emission
standards
and
continuous
monitoring
system
requirements.

B.
Testing
Requirements
All
hazardous
waste
combustors
must
commence
the
initial
comprehensive
performance
test
under
the
time
lines
discussed
above.
The
purpose
of
the
comprehensive
performance
test
is
to
document
compliance
with
the
emission
standards
of
the
final
rule
and
establish
operating
parameter
limits
to
maintain
compliance
with
those
standards.
You
must
also
conduct
periodic
comprehensive
performance
testing
every
five
years.

15
See
69
FR
at
21313
for
rationale.
We
received
no
adverse
comments
at
proposal.
If
your
source
is
subject
to
a
numerical
dioxin/
furan
emission
standard
(
i.
e.,
incinerators,
cement
kilns,
lightweight
aggregate
kilns
that
comply
with
the
0.2
ng
TEQ/
dscm
standard,
and
liquid
fuel
boilers
equipped
with
a
dry
air
pollution
control
device),
you
must
conduct
a
dioxin/
furan
confirmatory
performance
test
no
later
than
2.5
years
after
each
comprehensive
performance
test
(
i.
e.,
midway
between
comprehensive
performance
tests).
If
your
source
is
not
subject
to
a
numerical
dioxin/
furan
emission
standard
(
e.
g.,
solid
fuel
boilers,
lightweight
aggregate
kilns
that
comply
with
the
400
º
F
temperature
limit
at
the
kiln
exit,
liquid
fuel
boilers
equipped
with
wet
or
no
air
pollution
control
system,
and
hydrochloric
acid
production
furnaces),
you
must
conduct
a
one­
time
dioxin/
furan
test
to
enable
the
Agency
to
evaluate
the
effectiveness
of
the
carbon
monoxide/
hydrocarbon
standard
and
the
destruction
and
removal
efficiency
standard
in
controlling
dioxin/
furan
emissions
for
those
sources.
Previous
dioxin/
furan
emission
tests
may
be
used
to
meet
this
requirement
if
the
combustor
operated
under
the
conditions
required
by
the
rule
and
if
design
and
operation
of
the
combustor
has
not
changed
since
the
test
in
a
manner
that
could
increase
dioxin/
furan
emissions.
The
Agency
will
use
those
emissions
data
when
reevaluating
the
MACT
standards
under
CAA
section
112(
d)(
6),
when
determining
whether
to
develop
residual
risk
standards
for
these
sources
pursuant
to
section
112(
f)(
2),
and
when
determining
whether
the
source's
RCRA
Permit
is
protective
of
human
health
and
the
environment.
You
must
use
the
following
stack
test
methods
to
document
compliance
with
the
emission
standards:
(
1)
Method
29
for
mercury,
semivolatile
metals,
and
low
volatile
metals;
and
(
2)
Method
26/
26A,
Methods
320
or
321,
or
ASTM
D
6735­
01
for
hydrogen
chloride
and
chlorine16;
(
3)
either
Method
0023A
or
Method
23
for
dioxin/
furans;
and
(
4)
either
Method
5
or
5i
for
particulate
matter.

C.
Initial
Compliance
Requirements
The
initial
compliance
requirements
for
solid
fuel
boilers,
liquid
fuel
boilers,
and
hydrochloric
acid
production
furnaces
include17:
1.
You
must
place
in
the
operating
record
a
Documentation
of
Compliance
by
the
compliance
date
identifying
the
operating
parameter
limits
that,
using
available
information,
you
have
determined
will
ensure
compliance
with
the
emission
standards;
2.
You
must
develop
and
comply
with
a
startup,
shutdown,
and
malfunction
plan;
3.
You
must
install
an
automatic
waste
feed
cutoff
system
that
links
the
operating
parameter
limits
to
the
waste
feed
cutoff
system;
4.
You
must
control
combustion
system
leaks;
5.
You
must
establish
and
comply
with
an
operator
training
and
certification
program;
6.
You
must
establish
and
comply
with
an
operation
and
maintenance
plan;
7.
If
your
source
is
equipped
with
a
baghouse,
you
must
install
either
a
bag
leak
detection
system
or
a
particulate
matter
detection
system18;
and
16
Note
that
you
may
be
required
to
use
other
test
methods
to
document
emissions
of
hydrogen
chloride
and
chlorine
if
you
elect
to
comply
with
the
alternative,
health­
based
emission
limits
for
total
chlorine
under
§
63.1215.
See
§
63.1208(
b)(
5).
17
These
same
requirements
currently
apply
to
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
18
A
major
difference
between
a
bag
leak
detection
system
and
a
particulate
matter
detection
system
is
the
way
the
alarm
level
is
established.
The
alarm
level
for
a
bag
leak
detection
system
is
established
using
8.
If
your
source
is
equipped
with
an
electrostatic
precipitator
or
ionizing
wet
scrubber,
you
must
either
establish
site­
specific
control
device
operating
parameter
limits
which
limits
are
linked
to
the
automatic
waste
feed
cutoff
system,
or
install
a
particulate
matter
detection
system
and
take
corrective
measures
when
the
alarm
level
is
exceeded.

VII.
What
Are
the
Continuous
Compliance
Requirements?

The
continuous
compliance
requirements
for
solid
fuel
boilers,
liquid
fuel
boilers,
and
hydrochloric
acid
production
furnaces
are
identical
to
those
applicable
to
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
See
§
63.1209.
We
note,
however,
that
today's
final
rule
revises
some
of
these
requirements
as
they
apply
to
all
or
specific
HWCs
(
e.
g.,
bag
leak
detection
system
requirements;
optional
particulate
matter
detection
system
requirements;
compliance
assurance
for
thermal
emissions­
based
standards).
You
must
use
carbon
monoxide
or
hydrocarbon
continuous
emissions
monitors
(
as
well
as
an
oxygen
continuous
emissions
monitor
to
correct
the
carbon
monoxide
or
hydrocarbon
values
to
7%
oxygen)
to
ensure
compliance
with
the
carbon
monoxide
or
hydrocarbon
emission
standards.
You
must
also
establish
limits
(
as
applicable)
on
the
feedrate
of
metals,
chlorine,
and
ash,
key
combustor
operating
parameters,
and
key
operating
parameters
of
the
air
pollution
control
device
based
on
operations
during
the
comprehensive
performance
test.
You
must
continuously
monitor
these
parameters
with
a
continuous
monitoring
system.

VIII.
What
Are
the
Notification,
Recordkeeping,
and
Reporting
Requirements?

The
notification,
recordkeeping,
and
reporting
requirements
that
we
promulgate
today
for
solid
fuel
boilers,
liquid
fuel
boilers,
and
hydrochloric
acid
production
furnaces
are
identical
to
those
that
are
applicable
to
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
See
§
§
63.1210
and
63.1211.
We
note,
however,
that
today's
final
rule
revises
some
of
these
requirements
as
they
apply
to
all
or
specific
HWCs.
You
must
submit
notifications
including
the
following
to
the
permitting
authority
in
addition
to
those
required
by
the
NESHAP
General
Provisions,
subpart
A
of
40
CFR
part
63:
1.
Notification
of
changes
in
design,
operation,
or
maintenance
(
§
63.1206(
b)(
5)(
i));
2.
Notification
of
performance
test
and
continuous
monitoring
system
evaluation,
including
the
performance
test
plan
and
continuous
monitoring
system
performance
evaluation
plan
(
§
63.1207(
e));
3.
Notification
of
compliance,
including
results
of
performance
tests
and
continuous
monitoring
system
evaluations
(
§
§
63.1210(
b),
63.1207(
j);
63.1207(
k),
and
63.1207(
l));
and
4.
Various
notifications
if
you
request
or
elect
to
comply
with
alternative
requirements
at
§
63.1210(
a)(
2).
You
must
submit
the
following
reports
to
the
permitting
authority
in
addition
to
those
required
by
the
NESHAP
General
Provisions,
subpart
A
of
40
CFR
part
63:

concepts
in
the
Agency's
bag
leak
detection
system
guidance
document
while
the
alarm
level
for
a
particulate
matter
detection
system
is
established
based
on
the
detector
response
during
the
comprehensive
performance
test.
The
ash
feedrate
limit
for
incinerators
and
boilers
is
waived
if
you
use
a
particulate
matter
detection
system
but
not
if
you
use
a
bag
leak
detection
system
because
the
bag
leak
detection
system
alarm
level
may
not
provide
reasonable
assurance
of
continuous
compliance
with
the
particulate
matter
emission
standard.
1.
Startup,
shutdown,
and
malfunction
plan,
if
you
elect
to
comply
with
§
63.1206(
c)(
2)(
ii)(
B));
2.
Excessive
exceedances
report
(
§
63.1206(
c)(
3)(
vi));
and
3.
Emergency
safety
vent
opening
reports
(
§
63.1206(
c)(
4)(
iv)).
Finally,
you
must
keep
records
documenting
compliance
with
the
requirements
of
Subpart
EEE.
Recordkeeping
requirements
are
prescribed
in
§
63.1211(
b),
and
include
requirements
under
the
NESHAP
General
Provisions,
subpart
A
of
40
CFR
IX.
What
Is
the
Health­
Based
Compliance
Alternative
for
Total
Chlorine,
and
How
Do
I
Demonstrate
Eligibility?

A.
Overview
The
rule
allows
you
to
establish
and
comply
with
health­
based
compliance
alternatives
for
total
chlorine
for
hazardous
waste
combustors
other
than
hydrochloric
acid
production
furnaces
in
lieu
of
the
MACT
technology­
based
emission
standards
established
under
§
§
63.1216,
63.1217,
63.1219,
63.1220,
and
63.1221.
See
§
63.1215.
To
identify
and
comply
with
the
limits,
you
must:
(
1)
Identify
a
total
chlorine
emission
rate
for
each
on­
site
hazardous
waste
combustor.
You
may
select
total
chlorine
emission
rates
as
you
choose
to
demonstrate
eligibility
for
the
health­
based
limits,
except
the
total
chlorine
emission
rate
limits
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
cannot
result
in
total
chlorine
emission
concentrations
exceeding
the
Interim
Standards
provided
by
§
§
63.1203,
63.1204,
and
63.120519;
(
2)
Calculate
the
HCl­
equivalent
emission
rate
for
the
total
chlorine
emission
rates
you
select,
considering
long­
term
exposure
and
using
Reference
Concentrations
(
RfCs)
as
the
health
threshold
metric.
This
emission
rate
is
called
the
annual
average
HCl­
equivalent
emission
rate;
(
3)
Perform
an
eligibility
demonstration
to
determine
if
your
annual
average
HClequivalent
emission
rate
meets
the
national
exposure
standard
(
i.
e.,
Hazard
Index
not
exceeding
1.0
considering
the
maximum
annual
average
ambient
concentration
of
hydrogen
chloride
and
chlorine
at
an
off­
site
receptor
location
which
concentrations
are
attributable
to
all
on­
site
hazardous
waste
combustors)
and
thus
is
below
the
annual
average
HCl­
equivalent
emission
rate
limit;
(
4)
Calculate
the
HCl­
equivalent
emission
rate
for
the
total
chlorine
emission
rates
you
select,
considering
short­
term
exposure
and
using
acute
Reference
Exposure
Levels
(
aRELs)
as
the
health
threshold
metric.
This
emission
rate
is
called
the
1­
hour
average
HClequivalent
emission
rate.
(
5)
Determine
whether
your
1­
hour
HCl­
equivalent
emission
rate
may
exceed
the
national
exposure
standard
(
i.
e.,
Hazard
Index
not
exceeding
1.0
considering
the
maximum
1­
hour
average
ambient
concentration
of
hydrogen
chloride
and
chlorine
at
an
off­
site
receptor
location
which
concentrations
are
attributable
to
all
on­
site
hazardous
waste
combustors)
and
thus
may
exceed
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
when
complying
with
the
annual
average
HCl­
equivalent
emission
rate
limit,
absent
an
hourly
rolling
average
limit
on
the
feedrate
of
total
chlorine
and
chloride.

19
Note
that
the
final
rule
sunsets
the
Interim
Standards
on
the
compliance
date
of
today's
rule
but
codifies
the
Interim
Standards
for
total
chlorine
under
§
63.1215(
b)(
7).
(
6)
Submit
your
eligibility
demonstration,
including
your
determination
of
whether
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
may
be
exceeded
absent
an
hourly
rolling
average
limit
on
the
feedrate
of
total
chlorine
and
chloride,
for
review
and
approval;
(
7)
Document
during
the
comprehensive
performance
test
the
total
chlorine
system
removal
efficiency
for
each
combustor
and
use
this
system
removal
efficiency
to
calculate
chlorine
feedrate
limits.
Also,
document
that
total
chlorine
emissions
during
the
test
do
not
exceed
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
during
any
run
of
the
test.
In
addition,
establish
operating
limits
on
the
emission
control
device
based
on
operations
during
the
comprehensive
performance
test;
and
(
8)
Comply
with
the
requirements
for
changes
in
the
design,
operation,
or
maintenance
of
the
facility
which
could
affect
the
HCl­
equivalent
emission
rate
limits
or
system
removal
efficiency
for
total
chlorine,
and
changes
in
the
vicinity
of
your
facility
over
which
you
do
not
have
control
(
e.
g.,
new
receptors
locating
proximate
to
the
facility).

B.
HCl­
Equivalent
Emission
Rates
You
must
express
total
chlorine
emission
rates
(
lb/
hr)
from
each
on­
site
hazardous
waste
combustor,
including
hydrochloric
acid
production
furnaces20,
as
an
annual
average
HCl­
equivalent
emission
rate
and
a
1­
hour
average
HCl­
equivalent
emission
rate.
See
§
63.1215(
b).
The
annual
average
HCl­
equivalent
emission
rate
equates
chlorine
emission
rates
to
hydrogen
chloride
(
HCl)
emission
rates
using
Reference
Concentrations
(
RfCs)
as
the
health
risk
metric
for
long­
term
exposure.
The
1­
hour
average
HCl­
equivalent
emission
rate
equates
chlorine
emission
rates
to
HCl
emission
rates
using
1­
hour
Reference
Exposure
Levels
(
aRELs)
as
the
health
risk
metric
for
acute
exposure.
To
calculate
HCl­
equivalent
emission
rates,
you
must
apportion
total
chlorine
emissions
(
ppmv)
between
chlorine
and
HCl
using
the
volumetric
ratio
of
chlorine
to
hydrogen
chloride
(
Cl2/
HCl).
 
To
calculate
the
annual
average
HCl­
equivalent
emission
rate
(
lb/
hr)
and
the
emission
rate
limit,
you
must
use
the
historical
average
Cl2/
HCl
volumetric
ratio
from
all
regulatory
compliance
tests
and
the
gas
flowrate
(
and
other
relevant
parameters)
from
the
most
recent
RCRA
compliance
test
or
MACT
performance
test.
 
To
calculate
the
1­
hour
average
HCl­
equivalent
emission
rate
(
lb/
hr)
and
emission
rate
limit,
you
must
use
the
highest
Cl2/
HCl
volumetric
ratio
from
all
regulatory
compliance
tests
and
the
gas
flowrate
from
the
most
recent
RCRA
compliance
test
or
MACT
performance
test.
 
If
you
believe
that
the
Cl2/
HCl
volumetric
ratio
for
one
or
more
historical
compliance
tests
is
not
representative
of
the
current
ratio,
you
may
request
that
the
permitting
authority
allow
you
to
screen
those
ratios
from
the
analysis
of
historical
ratios.
 
If
the
permitting
authority
believes
that
too
few
historical
Cl2/
HCl
ratios
are
available
to
establish
a
representative
average
ratio
and
a
representative
maximum
ratio,
the
permitting
authority
may
require
you
to
conduct
periodic
testing
to
establish
representative
ratios.

20
Although
hydrochloric
acid
production
furnaces
are
not
eligible
for
the
health­
based
total
chlorine
emission
limits
(
because
control
of
total
chlorine
is
a
surrogate
for
control
of
metal
HAP),
you
must
consider
total
chlorine
emissions
from
hydrochloric
acid
production
furnaces
when
demonstrating
that
total
chlorine
emissions
from
all
on­
site
hazardous
waste
combustors
will
not
exceed
the
Hazard
Index
limit
of
1.0
at
an
offsite
receptor
location.
 
You
must
include
the
Cl2/
HCl
volumetric
ratio
demonstrated
during
each
performance
test
in
your
data
base
of
historical
Cl2/
HCl
ratios
to
update
the
ratios
for
subsequent
calculations
of
the
annual
average
and
1­
hour
average
HCl­
equivalent
emission
rates
(
and
emission
rate
limits).

C.
Eligibility
Demonstration
You
must
perform
an
eligibility
demonstration
to
determine
whether
the
total
chlorine
emission
rates
you
select
for
each
on­
site
hazardous
waste
combustor
meet
the
national
exposure
standard
(
i.
e.,
the
Hazard
Index
of
1.0
cannot
be
exceeded
at
an
off­
site
receptor
location
considering
maximum
annual
average
ambient
concentrations
attributable
to
all
onsite
hazardous
waste
combustors
and
the
RfCs
for
HCl
and
chlorine)
using
either
a
look­
up
table
analysis
or
a
site­
specific
compliance
demonstration.
21
Eligibility
for
the
health­
based
total
chlorine
standard
is
determined
by
comparing
the
annual
average
HCl­
equivalent
emission
rate
for
the
total
chlorine
emission
rate
you
select
for
each
combustor
to
the
annual
average
HCl­
equivalent
emission
rate
limit.
The
annual
average
HCl­
equivalent
emission
rate
limit
is
the
HCl­
equivalent
emission
rate,
determined
by
equating
the
toxicity
of
chlorine
to
HCl
using
RfCs
as
the
health
risk
metric
for
long­
term
exposure,
which
ensures
that
maximum
annual
average
ambient
concentrations
of
HCl
equivalents
do
not
exceed
a
Hazard
Index
of
1.0,
rounded
to
the
nearest
tenths
decimal
place
(
0.1)
and
considering
all
on­
site
hazardous
waste
combustors.
See
§
63.1215(
b)(
2).
Your
facility
is
eligible
for
the
health­
based
compliance
alternatives
for
total
chlorine
if
either:
(
1)
the
annual
average
HCl­
equivalent
emission
rate
for
each
on­
site
hazardous
waste
combustor
is
below
the
HCl­
equivalent
emission
rate
limit
determined
from
the
appropriate
value
for
the
emission
rate
limit
in
the
applicable
look­
up
table
and
the
proration
procedure
for
multiple
combustors
discussed
below;
or
(
2)
the
annual
average
HClequivalent
emission
rate
for
each
on­
site
hazardous
waste
combustor
is
below
the
annual
average
HCl­
equivalent
emission
rate
limit
you
calculate
based
on
a
site­
specific
compliance
demonstration.
1.
Look­
Up
Table
Analysis
Look­
up
tables
for
the
eligibility
demonstration
are
provided
as
Tables
1
and
2
to
§
63.1215.
Table
1
presents
annual
average
HCl­
equivalent
emission
rate
limits
for
sources
located
in
flat
terrain.
For
purposes
of
this
analysis,
flat
terrain
is
terrain
that
rises
to
a
level
not
exceeding
one
half
the
stack
height
within
a
distance
of
50
stack
heights.
Table
2
presents
annual
average
HCl­
equivalent
emission
rate
limits
for
sources
located
in
simple
elevated
terrain.
For
purposes
of
this
analysis,
simple
elevated
terrain
is
terrain
that
rises
to
a
level
exceeding
one
half
the
stack
height,
but
that
does
not
exceed
the
stack
height
within
a
distance
of
50
stack
heights.
If
your
facility
is
not
located
in
either
flat
or
simple
elevated
terrain,
you
must
conduct
a
site­
specific
compliance
demonstration.
To
determine
the
annual
average
HCl­
equivalent
emission
rate
limit
for
a
source
from
the
look­
up
table,
you
must
use
the
stack
height
and
stack
diameter
for
your
hazardous
waste
21
The
total
chlorine
emission
rates
(
lb/
hr)
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
cannot
result
in
total
chlorine
emission
concentrations
(
ppmv)
exceeding
the
Interim
Standards
provided
by
§
§
63.1203,
63.1204,
and
63.1205.
The
final
rule
sunsets
the
Interim
Standards
on
the
compliance
date
of
today's
rule
but
codifies
the
Interim
Standards
for
total
chlorine
under
§
63.1215(
b)(
7).
combustors
and
the
distance
between
the
stack
and
the
property
boundary.
If
any
of
these
values
for
stack
height,
stack
diameter,
and
distance
to
nearest
property
boundary
do
not
match
the
exact
values
in
the
look­
up
table,
you
must
use
the
next
lowest
table
value.
If
you
have
more
than
one
hazardous
waste
combustor
on
site,
you
must
adjust
the
emission
rate
limits
provided
by
the
tables
such
that
the
sum
of
the
ratios
for
all
combustors
of
the
adjusted
emission
rate
limit
to
the
emission
rate
limit
provided
by
the
table
cannot
exceed
1.0.
See
§
63.1215
(
c)(
3)(
v).
2.
Site­
Specific
Compliance
Demonstration
You
may
use
any
scientifically­
accepted
peer­
reviewed
risk
assessment
methodology
for
your
site­
specific
compliance
demonstration
to
calculate
an
annual
average
HClequivalent
emission
rate
limit
for
each
on­
site
hazardous
waste
combustor.
An
example
of
one
approach
for
performing
the
demonstration
for
air
toxics
can
be
found
in
the
EPA's
``
Air
Toxics
Risk
Assessment
Reference
Library,
Volume
2,
Site­
Specific
Risk
Assessment
Technical
Resource
Document,''
which
may
be
obtained
through
the
EPA's
Air
Toxics
Web
site
at
http://
www.
epa.
gov/
ttn/
atw.
To
determine
the
annual
average
HCl­
equivalent
emission
rate
limit
for
each
on­
site
hazardous
waste
combustor,
your
site­
specific
compliance
demonstration
must,
at
a
minimum:
(
1)
estimate
long­
term
inhalation
exposures
through
the
estimation
of
annual
or
multi­
year
average
ambient
concentrations;
(
2)
estimate
the
inhalation
exposure
for
the
actual
individual
most
exposed
to
the
facility's
emissions
from
hazardous
waste
combustors,
considering
locations
where
people
reside
and
where
people
congregate
for
work,
school,
or
recreation;
(
3)
use
site­
specific,
quality­
assured
data
wherever
possible;
(
4)
use
healthprotective
default
assumptions
wherever
site­
specific
data
are
not
available,
and:
(
5)
contain
adequate
documentation
of
the
data
and
methods
used
for
the
assessment
so
that
it
is
transparent
and
can
be
reproduced
by
an
experienced
risk
assessor
and
emissions
measurement
expert.
To
establish
the
annual
average
HCl­
equivalent
emission
rate
limit
for
each
combustor,
you
may
apportion
as
you
elect
among
the
combustors
the
annual
average
HClequivalent
emission
rate
limit
for
the
facility,
which
limit
ensures
that
the
RfC­
based
Hazard
Index
of
1.0
is
not
exceeded.

D.
Assurance
that
the
1­
Hour
HCl­
Equivalent
Emission
Rate
Will
Not
Be
Exceeded
The
long­
term,
RfC­
based
Hazard
Index
will
always
be
higher
than
the
short­
term,
aREL­
based
Hazard
Index
for
a
constant
HCl­
equivalent
emission
rate
because
the
health
threshold
levels
for
short­
term
exposure
are
orders
of
magnitude
higher
than
the
health
threshold
levels
for
long­
term
exposure.
22
Even
though
maximum
1­
hour
average
ambient
concentrations
are
substantially
higher
than
maximum
annual
average
concentrations,
the
higher
short­
term
ambient
concentrations
do
not
offset
the
much
higher
health
threshold
levels
for
short­
term
exposures.
Thus,
the
long­
term,
RfC­
based
Hazard
Index
will
always
govern
regarding
whether
a
source
can
make
an
eligibility
demonstration.
Accordingly,
eligibility
for
the
health­
based
emission
limits
is
based
solely
on
whether
a
source
can
comply
with
the
annual
average
HCl­
equivalent
emission
rate
limit.
Nonetheless,
some
sources
may
have
highly
variably
chlorine
feedrates
(
and
corresponding
highly
variable
HCl­
equivalent
emission
rates)
such
that
they
may
feed
22
USEPA,
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
24.2.
chlorine
at
very
high
levels
for
short
periods
of
time
and
still
remain
in
compliance
with
the
chlorine
feedrate
limit
established
to
ensure
compliance
with
the
annual
average
HClequivalent
emission
rate
limit.
23
To
ensure
that
the
1­
hour
HCl­
equivalent
emission
rate
limit
will
not
be
exceeded
during
these
periods
of
peak
emissions,
you
must
establish
a
1­
hour
average
HCl­
equivalent
emission
rate
and
1­
hour
average
HCl­
equivalent
emission
rate
limit
for
each
combustor
and
consider
site­
specific
factors
including
prescribed
criteria
to
determine
if
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
may
be
exceeded
absent
an
hourly
rolling
average
limit
on
chlorine
feedrate.
If
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
may
be
exceeded,
you
must
establish
an
hourly
rolling
average
feedrate
limit
on
chlorine.
You
must
calculate
the
1­
hour
average
HCl­
equivalent
emission
rate
from
the
total
chlorine
emission
rate
you
select
for
each
source.
You
must
establish
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
for
each
affected
source
using
either
a
look­
up
table
analysis
or
site­
specific
analysis.
Look­
up
tables
are
provided
for
1­
hour
average
HCl­
equivalent
emission
rate
limits
as
Table
3
and
Table
4
to
this
section.
Table
3
provides
limits
for
facilities
located
in
flat
terrain.
Table
4
provides
limits
for
facilities
located
in
simple
elevated
terrain.
You
must
use
the
Tables
to
establish
emission
rate
limits
in
the
same
manner
as
you
use
Tables
1
and
2
to
establish
annual
average
HCl­
equivalent
emission
rate
limits.
If
you
conduct
a
site­
specific
analysis
to
establish
a
1­
hour
average
HCl­
equivalent
emission
rate
limit,
you
must
follow
the
risk
assessment
procedures
you
used
to
establish
an
annual
average
HCl­
equivalent
emission
rate
limit.
The
1­
hour
HCl­
equivalent
emission
rate
limit,
however,
is
the
emission
rate
than
ensures
that
the
Hazard
Index
associated
with
maximum
1­
hour
average
exposures
is
not
greater
than
1.0.
You
must
consider
criteria
including
the
following
to
determine
if
a
source
may
exceed
the
1­
hour
HCl­
equivalent
emission
rate
limit
absent
an
hourly
rolling
average
chlorine
feedrate
limit:
(
1)
the
ratio
of
the
1­
hour
average
HCl­
equivalent
emission
rate
based
on
the
total
chlorine
emission
rate
you
select
for
each
hazardous
waste
combustor
to
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
for
the
combustor;
and
(
2)
the
potential
for
the
source
to
vary
total
chlorine
and
chloride
feedrates
substantially
over
the
averaging
period
for
the
feedrate
limit
you
establish
to
ensure
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit.
If
you
determine
that
a
source
may
exceed
the
1­
hour
average
HCl­
equivalent
emission
rate
limit,
you
must
establish
an
hourly
rolling
average
chlorine
feedrate
limit
as
discussed
below
in
Section
G.
You
must
include
the
following
information
in
your
eligibility
demonstration
to
document
your
determination
whether
an
hourly
rolling
average
feedrate
limit
is
needed
to
maintain
compliance
with
the
1­
hour
HCl­
equivalent
emission
rate
limit:
(
1)
determination
of
the
Cl2/
HCl
volumetric
ratio
established
for
1­
hour
average
HCl­
equivalent
emission
rate
determinations
as
provided
by
§
63.1215(
b)(
6)(
ii);
(
2)
determination
of
the
1­
hour
average
HCl­
equivalent
emission
rate
calculated
from
the
total
chlorine
emission
rate
you
select
for
the
combustor;
(
3)
determination
of
the
1­
hour
average
HCl­
equivalent
emission
rate
limit;
(
4)
determination
of
the
ratio
of
the
1­
hour
average
HCl­
equivalent
emission
rate
to
the
1­

23
See
discussion
below
in
Section
F
regarding
the
requirement
to
establish
chlorine
feedrate
limits.
hour
HCl­
equivalent
emission
rate
limit
for
the
combustor;
and
(
5)
determination
of
the
potential
for
the
source
to
vary
chlorine
feedrates
substantially
over
the
averaging
period
for
the
long­
term
feedrate
limit
(
i.
e.,
12­
hours,
or
up
to
annually)
established
to
maintain
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit.

E.
Review
and
Approval
of
Eligibility
Demonstrations
The
permitting
authority
will
review
and
approve
your
eligibility
demonstration.
Your
eligibility
demonstration
must
contain,
at
a
minimum,
the
information
listed
in
§
63.1215(
d)(
1).
1.
Review
and
Approval
for
Existing
Sources
If
you
operate
an
existing
source,
you
must
submit
the
eligibility
demonstration
to
your
permitting
authority
for
review
and
approval
not
later
than
12
months
prior
to
the
compliance
date.
You
must
also
submit
a
separate
copy
of
the
eligibility
demonstration
to:
U.
S.
EPA,
Risk
and
Exposure
Assessment
Group,
Emission
Standards
Division
(
C404
 
01),
Attn:
Group
Leader,
Research
Triangle
Park,
North
Carolina
27711,
electronic
mail
address
REAG@
epa.
gov.
Your
permitting
authority
should
notify
you
of
approval
or
intent
to
disapprove
your
eligibility
demonstration
within
6
months
after
receipt
of
the
original
demonstration,
and
within
3
months
after
receipt
of
any
supplemental
information
that
you
submit.
A
notice
of
intent
to
disapprove
your
eligibility
demonstration
will
identify
incomplete
or
inaccurate
information
or
noncompliance
with
prescribed
procedures
and
specify
how
much
time
you
will
have
to
submit
additional
information
or
to
comply
with
the
MACT
total
chlorine
standards.
If
your
eligibility
demonstration
is
disapproved,
the
permitting
authority
may
extend
the
compliance
date
of
the
total
chlorine
standard
to
allow
you
to
make
changes
to
the
design
or
operation
of
the
combustor
or
related
systems
as
quickly
as
practicable
to
enable
you
to
achieve
compliance
with
the
MACT
standard
for
total
chlorine.
If
your
permitting
authority
has
not
approved
your
eligibility
demonstration
by
the
compliance
date,
and
has
not
issued
a
notice
of
intent
to
disapprove
your
demonstration,
you
may
nonetheless
begin
complying,
on
the
compliance
date,
with
the
annual
average
HClequivalent
emission
rate
limits
you
present
in
your
eligibility
demonstration.
If
your
permitting
authority
issues
a
notice
of
intent
to
disapprove
your
eligibility
demonstration
after
the
compliance
date,
the
authority
will
identify
the
basis
for
that
notice
and
specify
how
much
time
you
will
have
to
submit
additional
information
or
to
comply
with
the
MACT
total
chlorine
standards.
The
permitting
authority
may
extend
the
compliance
date
of
the
total
chlorine
standard
to
allow
you
to
make
changes
to
the
design
or
operation
of
the
combustor
or
related
systems
as
quickly
as
practicable
to
enable
you
to
achieve
compliance
with
the
MACT
standard
for
total
chlorine.
2.
Review
and
Approval
for
New
and
Reconstructed
Sources
The
procedures
for
review
and
approval
of
eligibility
demonstrations
applicable
to
existing
sources
discussed
above
also
apply
to
new
or
reconstructed
sources,
except
that
the
date
you
must
submit
the
eligibility
demonstration
is
as
discussed
below.
If
you
operate
a
new
or
reconstructed
source
that
starts
up
by
[
INSERT
DATE
18
MONTHS
AFTER
THE
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER],
or
a
solid
fuel­
fired
boiler
or
liquid
fuel­
fired
boiler
that
is
an
area
source
that
increases
its
emissions
or
its
potential
to
emit
such
that
it
becomes
a
major
source
of
HAP
before
[
INSERT
DATE
18
MONTHS
AFTER
THE
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER],
you
must
either:
(
1)
submit
an
eligibility
demonstration
for
review
and
approval
by
[
INSERT
DATE
6
MONTHS
AFTER
THE
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
and
comply
with
the
HCl­
equivalent
emission
rate
limits
and
operating
requirements
you
establish
in
the
eligibility
demonstration;
or
(
2)
comply
with
the
final
total
chlorine
emission
standards
under
§
§
63.1216,
63.1217,
63.1219,
63.1220,
and
63.1221,
by
[
INSERT
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
or
upon
startup,
whichever
is
later,
except
for
a
standard
that
is
more
stringent
than
the
standard
proposed
on
April
20,
2004
for
your
source.
If
a
final
standard
is
more
stringent
than
the
proposed
standard,
you
may
comply
with
the
proposed
standard
until
[
INSERT
DATE
3
YEARS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
after
which
you
must
comply
with
the
final
standard.
If
you
operate
a
new
or
reconstructed
source
that
starts
up
on
or
after
[
INSERT
DATE
18
MONTHS
AFTER
THE
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER],
or
a
solid
fuel­
fired
boiler
or
liquid
fuel­
fired
boiler
that
is
an
area
source
that
increases
its
emissions
or
its
potential
to
emit
such
that
it
becomes
a
major
source
of
HAP
on
or
after
[
INSERT
DATE
18
MONTHS
AFTER
THE
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER],
you
must
comply
with
either
of
the
following.
You
may
submit
an
eligibility
demonstration
for
review
and
approval
12
months
prior
to
startup.
Alternatively,
you
may
comply
with
the
final
total
chlorine
emission
standards
under
§
§
63.1216,
63.1217,
63.1219,
63.1220,
and
63.1221
upon
startup.
If
the
final
standard
is
more
stringent
than
the
standard
proposed
for
your
source
on
April
20,
2004,
however,
and
if
you
start
operations
before
[
INSERT
DATE
3
YEARS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER],
you
may
comply
with
the
proposed
standard
until
[
INSERT
DATE
3
YEARS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
after
which
you
must
comply
with
the
final
standard.

F.
Testing
Requirements
You
must
comply
with
the
requirements
for
comprehensive
performance
testing
under
§
63.1207.
1.
Test
Methods
for
Stack
Gas
Containing
Alkaline
Particulate.
If
you
operate
a
cement
kiln
or
a
combustor
equipped
with
a
dry
acid
gas
scrubber,
you
must
use
EPA
Method
320/
321
or
ASTM
D
6735
 
01,
or
an
equivalent
method,
to
measure
hydrogen
chloride,
and
the
back­
half
(
caustic
impingers)
of
Method
26/
26A,
or
an
equivalent
method,
to
measure
chlorine.
2.
Test
Methods
for
Stack
Gas
Containing
High
Levels
of
Bromine
or
Sulfur.
If
you
operate
an
incinerator,
boiler,
or
lightweight
aggregate
kiln
and
your
feedstreams
contain
bromine
or
sulfur
during
the
comprehensive
performance
test
at
the
levels
indicated
below,
you
must
use
EPA
Method
320/
321
or
ASTM
D
6735
 
01,
or
an
equivalent
method,
to
measure
hydrogen
chloride,
and
Method
26/
26A,
or
an
equivalent
method,
to
measure
chlorine
and
hydrogen
chloride
combined.
You
must
determine
your
chlorine
emissions
to
be
the
higher
of:
(
1)
the
value
measured
by
Method
26/
26A,
or
an
equivalent
method;
or
(
2)
the
value
calculated
by
the
difference
between
the
combined
hydrogen
chloride
and
chlorine
levels
measured
by
Method
26/
26a,
or
an
equivalent
method,
and
the
hydrogen
chloride
measurement
from
EPA
Method
320/
321
or
ASTM
D
6735­
01,
or
an
equivalent
method.
These
procedures
apply
if
you
feed
during
the
comprehensive
performance
test
bromine
at
a
bromine/
chlorine
ratio
in
feedstreams
greater
than
5
percent
by
mass,
or
sulfur
at
a
sulfur/
chlorine
ratio
in
feedstreams
greater
than
50
percent
by
mass.
24
Finally,
you
should
precondition
the
M26/
26A
filter
for
one
hour
prior
to
beginning
the
performance
test
to
minimize
the
potential
for
a
low
bias
caused
by
adsorption/
absorption
of
hydrogen
chloride
on
the
filter.

G.
Monitoring
Requirements
You
must
establish
and
comply
with
limits
on
the
same
operating
parameters
that
apply
to
sources
complying
with
the
MACT
standard
for
total
chlorine
under
§
63.1209(
o),
except
that
feedrate
limits
on
total
chlorine
and
chloride
must
be
established
as
described
below.
1.
Feedrate
Limit
to
Ensure
Compliance
with
the
Annual
Average
HCl­
Equivalent
Emission
Rate
Limit
For
sources
subject
to
the
feedrate
limit
for
total
chlorine
and
chloride
under
§
63.1209(
n)(
4)
to
ensure
compliance
with
the
semivolatile
metals
standard,
the
feedrate
limit
(
and
averaging
period)
for
total
chlorine
and
chloride
to
ensure
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit
is
the
same
as
required
by
that
paragraph.
Thus,
the
chlorine
feedrate
limit
is
the
average
of
the
run
averages
during
the
comprehensive
performance
test,
and
is
established
as
a
12­
hour
rolling
average.
That
chlorine
feedrate
limit
cannot
exceed
the
numerical
value
(
i.
e.,
not
considering
the
averaging
period)
of
the
feedrate
limit
that
ensures
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit,
however.
Therefore,
the
numerical
value
of
the
total
chlorine
and
chloride
feedrate
limit
must
not
exceed
the
value
you
calculate
as
the
annual
average
HCl­
equivalent
emission
rate
limit
(
lb/
hr)
divided
by
[
1
 
system
removal
efficiency].
You
must
calculate
a
total
chlorine
system
removal
efficiency
for
each
test
run
of
the
comprehensive
performance
test
as
[
1­
total
chlorine
emission
rate
(
g/
s)
/
chlorine
feedrate
(
g/
s)],
and
calculate
the
average
system
removal
efficiency
of
the
test
run
averages.
If
your
source
does
not
control
total
chlorine,
you
must
assume
zero
system
removal
efficiency.
If
emissions
during
the
comprehensive
performance
test
exceed
the
annual
average
HCl­
equivalent
emission
rate
limit,
eligibility
for
the
health­
based
emission
limits
is
not
affected.
This
is
because
the
emission
rate
limit
is
an
annual
average
limit.
Compliance
is
based
on
a
12­
hour
rolling
average
chlorine
feedrate
limit
(
rather
than
an
(
up
to)
an
annual
averaging
period)
for
sources
subject
to
the
12­
hour
rolling
average
feedrate
limit
for
total
chlorine
and
chloride
under
§
63.1209(
n)(
4)
to
ensure
compliance
with
the
semivolatile
metals
standard
given
that
the
more
stringent
feedrate
limit
(
i.
e.,
the
feedrate
limit
with
the
shorter
averaging
period)
would
apply.
For
sources
exempt
from
the
feedrate
limit
for
total
chlorine
and
chloride
under
§
63.1209(
n)(
4)
because
they
comply
with
§
63.1207(
m)(
2)
(
which
allows
compliance
with
the
semivolatile
metals
emission
standard
absent
emissions
testing
by
assuming
all
metals
fed
are
emitted),
the
feedrate
limit
for
total
chlorine
and
chloride
to
ensure
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
must
be
established
as
follows:
 
You
must
establish
an
average
period
for
the
feedrate
limit
that
does
not
exceed
an
annual
rolling
average;

24
USEPA,
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
IV:
Compliance
with
the
HWC
MACT
Standards,"
September
2005,
Chapter
15.1.2.
 
You
must
calculate
a
total
chlorine
system
removal
efficiency
for
each
test
run
of
the
comprehensive
performance
test
as
[
1­
total
chlorine
emission
rate
(
g/
s)
/
chlorine
feedrate
(
g/
s)],
and
calculate
the
average
system
removal
efficiency
of
the
test
run
averages.
If
your
source
is
not
equipped
with
a
control
system
that
consistently
and
reproducibly
controls
total
emissions
(
e.
g.,
wet
or
dry
scrubber),
you
must
assume
zero
system
removal
efficiency.
If
emissions
during
the
comprehensive
performance
test
exceed
the
annual
average
HCl­
equivalent
emission
rate
limit,
eligibility
for
emission
limits
under
this
section
is
not
affected.
The
emission
rate
limit
is
an
annual
average
limit
and
compliance
is
based
on
an
annual
average
feedrate
limit
on
total
chlorine
and
chloride
(
or
a
shorter
averaging
period
if
you
so
elect
under
paragraph
(
g)(
2)(
ii)(
A)
of
this
section);
and
 
You
must
calculate
the
feedrate
limit
for
total
chlorine
and
chloride
as
the
annual
average
HCl­
equivalent
emission
rate
limit
(
lb/
hr)
divided
by
[
1
 
system
removal
efficiency]
and
comply
with
the
feedrate
limit
on
the
averaging
period
you
establish.
2.
Feedrate
Limit
to
Ensure
Compliance
with
the
1­
Hour
Average
HCl­
Equivalent
Emission
Rate
Limit
You
must
establish
an
hourly
rolling
average
feedrate
limit
on
total
chlorine
and
chloride
to
ensure
compliance
with
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
unless
you
determine
that
the
hourly
rolling
average
feedrate
limit
is
waived
as
discussed
under
Section
D
above.
If
required,
you
must
calculate
the
hourly
rolling
average
feedrate
limit
for
total
chlorine
and
chloride
as
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
(
lb/
hr)
divided
by
[
1­
system
removal
efficiency]
using
the
system
removal
efficiency
demonstrated
during
the
comprehensive
performance
test.

H.
Relationship
Among
Emission
Rates,
Emission
Rate
Limits,
and
Feedrate
Limits
We
summarize
here
the
relationship
among:
(
1)
the
total
chlorine
emission
rate
you
select
in
your
eligibility
demonstration;
(
2)
the
annual
average
and
1­
hour
average
HClequivalent
emission
rates
you
present
in
your
eligibility
demonstration;
(
3)
the
annual
average
and
1­
hour
average
emission
rate
limits
you
present
in
your
eligibility
demonstration;
(
4)
performance
test
emission
rates
for
total
chlorine
and
HCl­
equivalent
emissions;
and
(
5)
long­
term
and
hourly
rolling
average
chlorine
feedrate
limits.
1.
Total
Chlorine
Emission
Rate,
Annual
Average
HCl­
Equivalent
Emission
Rate,
and
Annual
Average
HCl­
Equivalent
Emission
Rate
Limit
For
the
eligibility
demonstration,
you
must
select
a
total
chlorine
emission
concentration
(
ppmv)
for
each
combustor,
determine
the
Cl2/
HCl
volumetric
ratio,
calculate
the
annual
average
HCl­
equivalent
emission
rate
(
lb/
hr),
and
document
that
the
emission
rate
does
not
exceed
the
annual
average
HCl­
equivalent
emission
rate
limit.
You
select
a
total
chlorine
(
i.
e.,
HCl
and
chlorine
combined)
emission
concentration
(
ppmv)
for
each
hazardous
waste
combustor
expressed
as
chloride
(
Cl(­))
equivalent.
For
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns,
this
emission
concentration
cannot
exceed
the
Interim
Standards
for
total
chlorine.
You
then
determine
the
average
Cl2/
HCl
volumetric
ratio
considering
all
historical
regulatory
emissions
tests
and
apportion
total
chlorine
emissions
between
Cl2
and
HCl
accordingly.
You
use
these
apportioned
volumetric
emissions
to
calculate
the
Cl2
and
HCl
emission
rates
(
lb/
hr)
using
the
average
gas
flowrate
(
and
other
relevant
parameters)
for
the
most
recent
RCRA
compliance
test
or
MACT
performance
test
for
total
chlorine.
Finally,
you
use
these
Cl2
and
HCl
emission
rates
to
calculate
an
annual
average
HCl­
equivalent
emission
rate,
which
cannot
exceed
the
annual
average
HCl­
equivalent
emission
rate
limit
that
you
establish
as
discussed
below.
To
establish
the
annual
average
HCl­
equivalent
emission
rate
limit,
you
may
either
use
Tables
1
or
2
in
§
63.1215
to
look­
up
the
limit,
or
conduct
a
site­
specific
risk
analysis.
Under
the
site­
specific
risk
analysis
option,
the
annual
average
HCl­
equivalent
emission
rate
limit
would
be
the
highest
emission
rate
that
the
risk
assessment
estimates
would
result
in
a
Hazard
Index
not
exceeding
1.0
for
the
actual
individual
most
exposed
to
the
facility's
emissions
considering
off­
site
locations
where
people
reside
and
where
people
congregate
for
work,
school,
or
recreation.
If
you
have
more
than
one
on­
site
hazardous
waste
combustor,
and
if
you
use
the
look­
up
tables
to
establish
the
annual
average
HCl­
equivalent
emission
rate
limits,
the
sum
of
the
ratios
for
all
combustors
of
the
annual
average
HCl­
equivalent
emission
rate
to
the
annual
average
HCl­
equivalent
emission
rate
limit
cannot
not
exceed
1.0.
This
will
ensure
that
the
RfC­
based
Hazard
Index
of
1.0
is
not
exceeded,
a
principle
criterion
of
the
eligibility
demonstration.
If
you
use
site­
specific
risk
analysis
to
demonstrate
that
a
Hazard
Index
of
1.0
is
not
exceeded,
you
would
generally
identify
for
each
combustor
the
maximum
annual
average
HCl­
equivalent
emission
rate
that
the
risk
assessment
estimates
would
result
in
an
RfC­
based
Hazard
Index
of
1.0
at
any
off­
site
receptor
location
(
i.
e.,
considering
locations
where
people
reside
and
where
people
congregate
for
work,
school,
or
recreation.
25
This
emission
rate
would
be
the
annual
average
HCl­
equivalent
emission
rate
limit
for
each
combustor.
2.
1­
Hour
Average
HCl­
Equivalent
Emission
Rate
and
Emission
Rate
Limit
As
discussed
in
Section
D
above,
you
must
determine
in
your
eligibility
demonstration
whether
the
1­
hour
HCl­
equivalent
emission
rate
limit
may
be
exceeded
absent
an
hourly
rolling
average
chlorine
feedrate
limit.
To
make
this
determination,
you
must
establish
a
1­
hour
average
HCl­
equivalent
emission
rate
and
a
1­
hour
average
HClequivalent
emission
rate
limit.
You
calculate
the
1­
hour
average
HCl­
equivalent
emission
rate
from
the
total
chlorine
emission
rate,
established
as
discussed
above,
using
the
equation
in
§
63.1215(
b)(
3).
You
establish
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
by
either
using
Tables
3
or
4
in
§
63.1215
to
look­
up
the
limit,
or
conducting
a
site­
specific
risk
analysis.
Under
the
site­
specific
risk
analysis
option,
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
would
be
the
highest
emission
rate
that
the
risk
assessment
estimates
would
result
in
an
aREL­
based
Hazard
Index
not
exceeding
1.0
at
any
off­
site
receptor
location
(
i.
e.,
considering
locations
where
people
reside
and
where
people
congregate
for
work,
school,
or
recreation).
3.
Performance
Test
Emissions
During
the
comprehensive
performance
test,
you
must
demonstrate
a
system
removal
efficiency
for
total
chlorine
as
[
1
 
TCl
emitted
(
lb/
hr)
/
chlorine
fed
(
lb/
hr)].
During
the
test,
however,
the
total
chlorine
emission
rate
you
select
for
each
combustor
and
the
annual
average
HCl­
equivalent
emission
rate
limit
can
exceed
the
levels
you
present
in
the
eligibility
demonstration.
This
is
because
those
emission
rates
are
annual
average
rates
and
need
not
be
complied
with
over
the
duration
of
three
runs
of
the
performance
test,
which
may
be
nominally
only
3
hours.

25
Note
again,
however,
that
the
total
chlorine
emission
concentration
(
ppmv)
is
capped
by
the
Interim
Standards
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
The
1­
hour
average
HCl­
equivalent
emission
rate
limit
cannot
be
exceeded
during
any
run
of
the
comprehensive
performance
test,
however.
This
limit
is
based
on
an
aREL
Hazard
Index
of
1.0;
an
exceedance
of
the
limit
over
a
test
run
with
a
nominal
1­
hour
duration
would
result
in
a
Hazard
Index
of
greater
than
1.0.
4.
Chlorine
Feedrate
Limits
To
maintain
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit,
you
must
establish
a
long­
term
average
chlorine
feedrate
limit.
In
addition,
if
you
determine
under
§
63.1205(
d)(
3)
that
the
1­
hour
average
HCl­
equivalent
emission
rate
may
be
exceeded
(
i.
e.,
because
your
chlorine
feedrate
may
vary
substantially
over
the
averaging
period
for
the
long­
term
chlorine
feedrate
limit),
you
must
establish
an
hourly
rolling
average
chlorine
feedrate
limit.
Long­
Term
Chlorine
Feedrate
Limit.
The
chlorine
feedrate
limit
to
maintain
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
is
either:
(
1)
the
chlorine
feedrate
during
the
comprehensive
performance
test
if
you
demonstrate
compliance
with
the
semivolatile
metals
emission
standard
during
the
test
(
see
§
63.1209(
o));
or
(
2)
if
you
comply
with
the
semivolatile
metals
emission
standard
under
§
63.1207(
m)(
2)
by
assuming
all
metals
in
the
feed
to
the
combustor
are
emitted,
the
HCl­
equivalent
emission
rate
limit
divided
by
[
1
 
system
removal
efficiency]
where
you
demonstrate
the
system
removal
efficiency
during
the
comprehensive
performance
test.
If
you
establish
the
chlorine
feedrate
limit
based
on
the
feedrate
during
the
performance
test
to
demonstrate
compliance
with
the
semivolatile
metals
emission
standard,
the
averaging
period
for
the
feedrate
limit
is
a
12­
hour
rolling
average.
If
you
establish
the
chlorine
feedrate
limit
based
on
the
system
removal
efficiency
during
the
performance
test,
the
averaging
period
is
up
to
an
annual
rolling
average.
See
discussion
in
Part
Four,
Section
VII.
B
of
this
preamble.
If
you
comply
with
the
semivolatile
metals
emission
standard
under
§
63.1207(
m)(
2),
however,
the
long­
term
chlorine
feedrate
limit
is
based
on
the
system
removal
efficiency
during
the
comprehensive
performance
test
rather
than
the
feedrate
during
the
performance
test.
This
is
because
the
averaging
period
for
this
chlorine
feedrate
limit
(
that
ensures
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit)
is
up
to
an
annual
rolling
average.
See
§
63.1215(
g)(
2).
Thus,
the
chlorine
feedrate,
and
total
chlorine
emissions,
can
be
higher
than
the
limit
during
the
relatively
short
duration
of
the
comprehensive
performance
tests.
Hourly
Rolling
Average
Chlorine
Feedrate
Limit.
If
you
determine
under
§
63.1205(
d)(
3)
that
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
may
be
exceeded,
you
must
establish
an
hourly
rolling
average
chlorine
feedrate
limit.
That
feedrate
limit
is
established
as
the
1­
hour
HCl­
equivalent
emission
rate
limit
divided
by
[
1
 
system
removal
efficiency].
The
hourly
rolling
average
chlorine
feedrate
limit
is
not
established
based
on
feedrates
during
the
performance
test
because
performance
test
feedrates
may
be
substantially
lower
than
the
feedrate
needed
to
ensure
compliance
with
the
1­
hour
average
HCl­
equivalent
emission
rate.
Note,
however,
that
the
hourly
rolling
average
feedrate
limit
cannot
be
exceeded
during
any
run
of
the
comprehensive
performance
test.
This
chlorine
feedrate
limit
is
based
on
the
1­
hour
average
HCl­
equivalent
emission
rate
limit,
which
is
based
on
an
aREL
Hazard
Index
of
1.0.
Thus,
an
exceedance
of
the
hourly
rolling
average
feedrate
limit
(
and
the
1­
hour
lHCl­
equivalent
emission
rate
limit)
over
a
test
run
with
a
nominal
1­
hour
duration
would
result
in
a
Hazard
Index
of
greater
than
1.0.
I.
Changes
Your
requirements
will
change
in
response
to
changes
that
affect
the
HCl­
equivalent
emission
rate
or
HCl­
equivalent
emission
rate
limit
for
a
source.
1.
Changes
Over
Which
You
Have
Control
Changes
That
Affect
HCl­
Equivalent
Emission
Rate
Limits.
If
you
plan
to
change
the
design,
operation,
or
maintenance
of
the
facility
in
a
manner
that
would
decrease
the
annual
average
or
1­
hour
average
HCl­
equivalent
emission
rate
limit
(
e.
g.,
reduce
the
distance
to
the
property
line;
reduce
stack
gas
temperature;
reduce
stack
height),
prior
to
the
change
you
must
submit
to
the
permitting
authority
a
revised
eligibility
demonstration
documenting
the
lower
emission
rate
limits
and
calculations
of
reduced
total
chlorine
and
chloride
feedrate
limits.
If
you
plan
to
change
the
design,
operation,
or
maintenance
of
the
facility
in
a
manner
than
would
increase
the
annual
average
or
1­
hour
average
HCl­
equivalent
emission
rate
limit,
and
you
elect
to
increase
your
total
chlorine
and
chloride
feedrate
limits,
prior
to
the
change
you
must
submit
to
the
permitting
authority
a
revised
eligibility
demonstration
documenting
the
increased
emission
rate
limits
and
calculations
of
the
increased
feedrate
limits
prior
to
the
change.
Changes
That
Affect
System
Removal
Efficiency.
If
you
plan
to
change
the
design,
operation,
or
maintenance
of
the
combustor
in
a
manner
than
could
decrease
the
system
removal
efficiency,
you
are
subject
to
the
requirements
of
§
63.1206(
b)(
5)
for
conducting
a
performance
test
to
reestablish
the
combustor's
system
removal
efficiency.
You
also
must
submit
a
revised
eligibility
demonstration
documenting
the
lower
system
removal
efficiency
and
the
reduced
feedrate
limits
on
total
chlorine
and
chloride.
If
you
plan
to
change
the
design,
operation,
or
maintenance
of
the
combustor
in
a
manner
than
could
increase
the
system
removal
efficiency,
and
you
elect
to
document
the
increased
system
removal
efficiency
to
establish
higher
feedrate
limits
on
total
chlorine
and
chloride,
you
are
subject
to
the
requirements
of
§
63.1206(
b)(
5)
for
conducting
a
performance
test
to
reestablish
the
combustor's
system
removal
efficiency.
You
must
also
submit
a
revised
eligibility
demonstration
documenting
the
higher
system
removal
efficiency
and
the
increased
feedrate
limits
on
total
chlorine
and
chloride.
2.
Changes
Over
Which
You
Do
Not
Have
Control
If
you
use
site­
specific
risk
assessment
in
lieu
of
the
look­
up
tables
to
establish
the
HCl­
equivalent
emission
rate
limit,
you
must
review
the
documentation
you
use
in
your
eligibility
demonstration
every
five
years
from
the
date
of
the
comprehensive
performance
test
and
submit
for
review
and
approval
with
the
comprehensive
performance
test
plan
either
a
certification
that
the
information
used
in
your
eligibility
demonstration
has
not
changed
in
a
manner
that
would
decrease
the
annual
average
HCl­
equivalent
emission
rate
limit,
or
a
revised
eligibility
demonstration.
Examples
of
changes
beyond
your
control
that
may
decrease
the
annual
average
HCl­
equivalent
emission
rate
limit
(
or
1­
hour
average
HClequivalent
emission
rate
limit)
are
construction
of
residences
at
a
location
exposed
to
higher
ambient
concentrations
than
evaluated
during
your
previous
risk
analysis,
or
a
reduction
in
the
RfCs
or
aRELs.
If,
in
the
interim
between
the
dates
of
your
comprehensive
performance
tests,
you
have
reason
to
know
of
changes
that
would
decrease
the
annual
average
HCl­
equivalent
emission
rate
limit,
you
must
submit
a
revised
eligibility
demonstration
as
soon
as
practicable
but
not
more
frequently
than
annually.
If
you
determine
that
you
cannot
demonstrate
compliance
with
a
lower
annual
average
HCl­
equivalent
emission
rate
limit
(
dictated
by
a
change
over
which
you
do
not
have
control)
during
the
comprehensive
performance
test
because
you
need
additional
time
to
complete
changes
to
the
design
or
operation
of
the
source
or
related
systems,
you
may
request
that
the
permitting
authority
grant
you
additional
time
to
make
those
changes
as
quickly
as
practicable.

X.
Overview
on
Floor
Methodologies
The
most
contentious
issue
in
the
rulemaking
involved
methodologies
for
determining
MACT
floors,
namely,
which
sources
are
best
performing,
and
what
is
their
level
of
performance.
Superficially,
these
questions
have
a
ready
answer:
the
best
performers
are
the
lowest
emitters
as
measured
by
compliance
tests,
and
those
tests
fix
their
level
of
performance.
But
compliance
tests
are
snapshots
which
do
not
fully
capture
sources'
total
operating
variability.
Since
the
standards
must
be
met
at
all
times,
picking
lowest
compliance
test
data
to
set
the
standard
results
in
standards
best
performing
sources
themselves
would
be
unable
to
meet
at
all
times.
To
avoid
this
impermissible
result,
EPA
selected
approaches
that
reasonably
estimate
best
performing
sources'
total
variability.
Certain
types
of
variability
can
be
quantified
statistically,
and
EPA
did
so
here
(
using
standard
statistical
approaches)
in
all
of
the
floor
methodologies
used
in
the
rule.
There
are
other
components
of
variability,
however,
which
cannot
be
fully
quantified,
but
nonetheless
must
be
accounted
for
in
reasonably
estimating
best
performing
sources'
performance
over
time.
EPA
selected
ranking
methodologies
which
best
account
for
this
total
variability.
Where
control
of
the
feed
of
HAP
is
feasible
and
technically
assessable
(
the
case
for
HAP
metals
and
for
total
chlorine),
EPA
used
a
methodology
that
ranked
sources
by
their
ability
to
best
control
both
HAP
feed
and
HAP
emissions.
This
methodology
thus
assesses
the
efficiency
of
control
of
both
the
HAP
inputs
to
a
hazardous
waste
combustion
unit,
and
the
efficiency
of
control
of
the
unit's
outputs.
This
methodology
reasonably
selects
the
best
performing
(
and
for
new
sources,
best
controlled)
sources,
and
reasonably
assesses
their
level
of
performance.
When
HAP
feed
control
is
not
feasible,
notably
where
HAP
is
contributed
by
raw
material
and
fossil
fuel
inputs,
EPA
determined
best
performers
and
their
level
of
performance
using
a
methodology
that
selects
the
lowest
emitters
using
the
best
air
pollution
control
technology.
This
methodology
reasonably
estimates
the
best
performing
sources'
level
of
performance,
and
better
accounts
for
total
variability
in
emissions
levels
of
the
best
performing
sources.
EPA
carefully
examined
approaches
selecting
lowest
emitters
as
best
performers.
Examination
of
other
test
conditions
from
the
same
best
performing
sources
shows,
however,
that
this
approach
results
in
standards
not
achievable
even
by
the
best
performers.
Indeed,
in
order
to
meet
such
standards,
even
"
best
performing"
sources
(
lowest
emitting
in
individual
tests)
would
have
to
add
additional
air
pollution
control
technology.
EPA
views
this
result
as
an
end
run
around
the
section
112
(
d)
(
2)
beyond­
the­
floor
process,
because
floor
standards
would
force
industry­
wide
technological
changes
without
consideration
of
the
factors
(
cost
and
energy
in
particular)
which
Congress
mandated
for
consideration
when
establishing
beyond­
the­
floor
standards.
Part
Three:
What
Are
the
Major
Changes
Since
Proposal?

I.
Database
A.
Hazardous
Burning
Incinerators
Five
incinerators
have
been
removed
from
the
database
because
they
have
initiated
or
completed
RCRA
closure.
26
Two
incinerators
have
been
added
to
the
list
of
sources
used
to
calculate
the
floor
levels.
27
Emissions
data
from
source
3015
has
been
excluded
for
purposes
of
calculating
the
particulate
matter
floor
because
the
source
was
processing
an
atypical
waste
stream
from
a
particulate
matter
compliance
perspective.
See
part
four,
section
I.
F.
We
have
excluded
the
most
recent
mercury
and
dioxin/
furan
emissions
data
from
source
327,
and
have
instead
used
data
from
an
older
test
condition
to
represent
this
source's
emissions
because
the
source
encountered
problems
with
its
carbon
injection
system
during
the
most
recent
test.
See
part
four,
section
I.
F.
Emissions
data
from
source
3006
has
been
excluded
for
purposes
of
calculating
the
semivolatile
metal
standard
because
this
source
did
not
measure
cadmium
emissions
during
its
emissions
test.
See
part
four,
section
I.
F.
We
have
added
mercury
emissions
data
from
source
901
(
DSSI)
to
the
incinerator
mercury
database
because
this
source
(
which
is
otherwise
subject
to
standards
for
liquid
fuel
boilers)
is
burning
a
waste
which
is
unlike
that
burned
by
any
other
liquid
fuel
boiler
with
respect
to
mercury
concentration
and
waste
provenance,
but
typical
of
waste
burned
by
incinerators
with
respect
to
those
factors.
See
part
four,
section
VI.
D.
1.
This
change
correspondingly
affects
the
liquid
fuel
boiler
standard
by
removing
that
data
from
the
liquid
fuel
boiler
database.

B.
Hazardous
Waste
Cement
Kilns
1.
Use
of
Emissions
Data
from
Ash
Grove
Cement
Company
The
emissions
data
from
Ash
Grove
Cement
Company,
which
operates
a
recently
constructed
preheater/
precalciner
kiln
located
in
Chanute,
Kansas,
are
considered
when
calculating
MACT
floors
for
new
hazardous
waste
burning
cement
kilns.
In
the
proposal,
we
did
not
consider
their
emissions
data
in
the
floor
analyses
for
existing
sources
because
Ash
Grove
Cement
used
the
data
to
demonstrate
compliance
with
the
new
source
interim
standards,
and
did
not
address
the
data
for
purposes
of
new
source
standards.
See
69
FR
at
21217
n.
35.
Consistent
with
our
position
on
use
of
post­
1999
emissions
data,
we
are
including
Ash
Grove
Cement's
emissions
data
in
the
floor
analyses
for
new
sources.
See
also
Part
Four,
Section
I.
B
of
the
preamble.
2.
Removal
of
Holcim's
Emissions
Data
from
EPA's
HWC
Data
Base
Following
cessation
of
hazardous
waste
operations
in
2003,
we
are
removing
all
emissions
data
from
both
wet
process
cement
kilns
at
Holcim's
Holly
Hill,
South
Carolina,
plant
from
our
hazardous
waste
combustor
data
base.
This
is
consistent
with
our
approach
in
both
this
rule
and
the
1999
rule
to
base
the
standards
only
on
performance
of
sources
that
actually
are
operating
(
i.
e.,
burning
hazardous
waste).
See
also
Part
Four,
Section
I.
A
and
64
FR
at
52844.

26
See
"
Final
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
II:
HWC
Database"
for
a
list
of
the
sources
that
have
initiated
or
completed
RCRA
closure.
27
We
noticed
the
data
from
these
sources
but
did
not
include
them
in
the
MACT
standard
calculations
at
proposal.
Note
that
inclusion
of
these
sources
did
not
affect
any
of
the
calculated
MACT
standards.
See
"
Final
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
II:
HWC
Database"
for
more
discussion.
3.
Use
of
Mercury
Data
As
discussed
below,
we
are
using
a
commenter­
submitted
dataset
as
the
basis
of
the
mercury
standards
for
existing
and
new
cement
kilns.
This
comprehensive
dataset
documents
the
day­
to­
day
levels
of
mercury
in
hazardous
waste
fired
to
all
cement
kilns
for
a
three
year
period
covering
1999
to
2001.
We
have
determined
that
the
commenter­
submitted
data
are
more
representative
than
data
used
at
proposal.
See
Part
Four,
Section
I.
D
of
the
preamble
for
our
rationale.

C.
Hazardous
Waste
Lightweight
Aggregate
Kilns
We
are
incorporating
mercury
data
submitted
by
a
commenter
into
the
MACT
floor
analysis
for
existing
and
new
lightweight
aggregate
kilns.
These
data
document
the
day­
today
levels
of
mercury
in
hazardous
waste
fired
to
lightweight
aggregate
kilns
located
at
Solite
Corporation's
Arvonia
plant
between
October
2003
and
June
2004.
We
have
determined
that
the
commenter­
submitted
data
are
more
representative
than
the
data
used
at
proposal.
See
Part
Four,
Section
I.
E
of
the
preamble
for
our
rationale.

D.
Liquid
Fuel
Boilers
In
the
proposed
rule,
we
classified
liquid
fuel
boilers
as
one
category.
The
final
rule
classifies
them
into
two
for
purposes
of
the
mercury,
semivolatile
metals,
chromium,
and
total
chlorine
standards:
one
for
liquid
fuel
boilers
burning
lower
heating
value
hazardous
waste
(
hazardous
waste
with
a
heating
value
less
than
10,000
Btu/
lb),
and
another
for
liquid
fuel
boilers
burning
higher
heating
value
hazardous
waste
(
hazardous
waste
with
a
heating
value
of
10,000
Btu/
lb
or
greater).
We
also
made
other,
minor
changes
to
the
data
base
because
some
sources
have
initiated
closure,
were
misclassified
as
other
sources
in
the
proposed
rule,
or
were
inadvertently
not
considered
in
the
floor
calculations
although
the
sources'
test
reports
were
in
the
docket
at
proposal.

E.
HCl
Production
Furnaces
Six
of
the
17
hydrochloric
acid
production
furnaces
have
ceased
burning
hazardous
waste
since
proposal.
Consequently,
we
do
not
use
emissions
data
from
these
sources
to
establish
the
final
standards.
All
six
of
these
sources
were
equipped
with
waste
heat
recovery
boilers
and
had
relatively
high
dioxin/
furan
emissions.
In
addition,
we
reclassified
source
#
2020
as
a
boiler
based
on
comments
received
at
proposal.

F.
Total
Chlorine
Emissions
Data
Below
20
ppmv
We
corrected
all
the
total
chlorine
measurements
in
the
data
base
that
were
below
20
ppmv
to
account
for
potential
systemic
negative
biases
in
the
Method
0050
data
in
response
to
comments
on
the
proposed
rule.
See
the
discussion
in
Part
Four,
Section
I.
C.
1
below.
To
account
for
the
bias,
we
corrected
all
total
chlorine
emissions
data
that
were
below
20
ppmv
to
20
ppmv.
We
accounted
for
within­
test
condition
emissions
variability
for
the
corrected
data
by
imputing
a
standard
deviation
that
is
based
on
a
regression
analysis
of
runto
run
standard
deviation
versus
emission
concentration
for
all
data
above
20
ppmv.
This
approach
of
using
a
regression
analysis
to
impute
a
standard
deviation
is
similar
to
the
approach
we
used
to
account
for
total
variability
(
i.
e.,
test­
to­
test
and
within
test
variability)
of
PM
emissions
for
sources
that
use
fabric
filters.
II.
Emission
Limits
A.
Incinerators
The
changes
in
the
incinerator
standards
for
existing
sources
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Dioxin/
Furans
(
ng
TEQ/
dscm)
Sources
with
dry
air
pollution
control
systems
or
waste
heat
boilers:
0.28;
For
others:
0.2
or
0.4
and
temperature
control
at
inlet
of
air
pollution
control
device
<
400
°
F
For
all
sources,
0.20
or
0.40
and
temperature
control
<
400
°
F
at
the
air
pollution
control
device
inlet
Particulate
Matter
(
gr/
dscf)
0.015
0.013
Semivolatile
Metals
(
ug/
dscm)
59
230
Low
Volatile
Metals
(
ug/
dscm)
84
92
Total
Chlorine
(
ppmv)
1.5
32
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
lead,
cadmium
and
selenium
(
ug/
dscm)
59
230
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
arsenic,
berrylium,
chrome,
antimony,
cobalt,
manganese,
and
nickel
(
ug/
dscm)
84
92
The
changes
in
the
incinerator
standards
for
new
sources
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Particulate
Matter
(
gr/
dscf)
0.0007
0.0015
Mercury
(
ug/
dscm)
8.0
8.1
Semivolatile
Metals
(
ug/
dscm)
6.5
10
Low
Volatile
Metals
(
ug/
dscm)
8.9
23
Total
Chlorine
(
ppmv)
0.18
21
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
lead,
cadmium
and
selenium
(
ug/
dscm)
6.5
10
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
arsenic,
berrylium,
chrome,
antimony,
cobalt,
manganese,
and
nickel
(
ug/
dscm)
8.9
23
B.
Hazardous
Waste
Burning
Cement
Kilns
The
changes
in
the
standards
for
existing
cement
kilns
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Mercury
(
ug/
dscm)
64
1
Both
3.0
ppmw2
and
either
120
ug/
dscm
(
stack
emissions)
or
120
ug/
dscm
(
expressed
as
a
hazardous
waste
MTEC)
3
Particulate
matter
0.028
gr/
dscf
0.028
gr/
dscf
and
20%
opacity4
Semivolatile
metals
4.0E­
04
lb/
MMBtu5
7.6E­
04
lb/
MMBtu5
and
330
ug/
dscm
Low
volatile
metals
1.4E­
05
lb/
MMBtu5
2.1E­
05
lb/
MMBtu5
and
56
ug/
dscm
Total
chlorine
(
ppmv)
6
110
120
1
The
proposed
mercury
standard
was
an
annual
limit.
2
Feed
concentration
of
mercury
in
hazardous
waste
as­
fired.
3
HW
MTEC
means
maximum
theoretical
emissions
concentration
of
the
hazardous
waste
and
MTEC
is
defined
at
§
63.1201(
a).
4
The
opacity
standard
does
not
apply
to
a
source
equipped
with
a
bag
leak
detection
system
under
§
63.1206(
c)(
8)
or
a
particulate
matter
detection
system
under
§
63.1206(
c)(
9).
5
Standard
is
expressed
as
mass
of
pollutant
stack
emissions
attributable
to
the
hazardous
waste
per
million
British
thermal
unit
heat
input
of
the
hazardous
waste.
6
Combined
standard,
reported
as
a
chloride
(
Cl(­))
equivalent.

The
changes
in
the
standards
for
new
cement
kilns
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Mercury
(
ug/
dscm)
35
1
Both
1.9
ppmw2
and
either
120
ug/
dscm
(
stack
emissions)
or
120
ug/
dscm
(
expressed
as
a
hazardous
waste
MTEC)
3
Particulate
matter
0.0058
gr/
dscf
0.0023
gr/
dscf
and
20%
opacity4
Semivolatile
metals
6.2E­
05
lb/
MMBtu5
6.2E­
05
lb/
MMBtu5
and
180
ug/
dscm
Low
volatile
metals
1.4E­
05
lb/
MMBtu5
1.5E­
05
lb/
MMBtu5
and
54
ug/
dscm
Total
chlorine
(
ppmv)
6
78
86
1
The
proposed
mercury
standard
was
an
annual
limit.
2
Feed
concentration
of
mercury
in
hazardous
waste
as­
fired.
3
HW
MTEC
means
maximum
theoretical
emissions
concentration
of
the
hazardous
waste
and
MTEC
is
defined
at
§
63.1201(
a).
4
The
opacity
standard
does
not
apply
to
a
source
equipped
with
a
bag
leak
detection
system
under
§
63.1206(
c)(
8)
or
a
particulate
matter
detection
system
under
§
63.1206(
c)(
9).
5
Standard
is
expressed
as
mass
of
pollutant
stack
emissions
attributable
to
the
hazardous
waste
per
million
British
thermal
unit
heat
input
of
the
hazardous
waste.
6
Combined
standard,
reported
as
a
chloride
(
Cl(­))
equivalent.

C.
Hazardous
Waste
Burning
Lightweight
Aggregate
Kilns
The
changes
in
the
standards
for
existing
lightweight
aggregate
kilns
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Dioxins
and
furans
(
ng
TEQ/
dscm)
0.40
0.20
or
rapid
quench
of
the
flue
gas
at
the
exit
of
the
kiln
to
less
than
400
°
F
Mercury
(
ug/
dscm)
67
1
120
ug/
dscm
(
stack
emissions)
or
120
ug/
dscm
(
expressed
as
a
hazardous
waste
MTEC)
2
Semivolatile
metals
3.1E­
04
lb/
MMBtu3
and
250
ug/
dscm
3.0E­
04
lb/
MMBtu3
and
250
ug/
dscm
1
The
proposed
mercury
standard
was
an
annual
limit.
2
HW
MTEC
means
maximum
theoretical
emissions
concentration
of
the
hazardous
waste
and
MTEC
is
defined
at
§
63.1201(
a).
3
Standard
is
expressed
as
mass
of
pollutant
stack
emissions
attributable
to
the
hazardous
waste
per
million
British
thermal
unit
heat
input
of
the
hazardous
waste.

The
changes
in
the
standards
for
new
lightweight
aggregate
kilns
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Dioxins
and
furans
(
ng
TEQ/
dscm)
0.40
0.20
or
rapid
quench
of
the
flue
gas
at
the
exit
of
the
kiln
to
less
than
400
°
F
Particulate
matter
0.0099
gr/
dscf
0.0098
gr/
dscf
Mercury
(
ug/
dscm)
67
1
120
ug/
dscm
(
stack
emissions)
or
120
ug/
dscm
(
expressed
as
a
hazardous
waste
MTEC)
2
Semivolatile
metals
2.4E­
05
lb/
MMBtu3
and
43
ug/
dscm
3.7E­
05
lb/
MMBtu3
and
43
ug/
dscm
1
The
proposed
mercury
standard
was
an
annual
limit.
2
HW
MTEC
means
maximum
theoretical
emissions
concentration
of
the
hazardous
waste
and
MTEC
is
defined
at
§
63.1201(
a).
3
Standard
is
expressed
as
mass
of
pollutant
stack
emissions
attributable
to
the
hazardous
waste
per
million
British
thermal
unit
heat
input
of
the
hazardous
waste.
D.
Solid
Fuel
Boilers
The
changes
in
the
solid
fuel
boiler
standards
for
existing
sources
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Mercury
(
ug/
dscm)
10
11
Semivolatile
Metals
(
ug/
dscm)
170
180
Low
Volatile
metals
(
ug/
dscm)
210
380
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
lead,
cadmium
and
selenium
(
ug/
dscm)
170
180
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
arsenic,
beryllium,
chromium,
antimony,
cobalt,
manganese,
and
nickel
(
ug/
dscm)
210
380
The
changes
in
the
solid
fuel
boiler
standards
for
new
sources
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Mercury
(
ug/
dscm)
10
11
Semivolatile
Metals
(
ug/
dscm)
170
180
Low
Volatile
metals
(
ug/
dscm)
210
380
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
lead,
cadmium
and
selenium
(
ug/
dscm)
170
180
E.
Liquid
Fuel
Boilers
We
redefined
the
liquid
fuel
boiler
subcategory
into
two
separate
boiler
subcategories
based
on
the
heating
value
of
the
hazardous
waste
they
burn:
those
that
burn
waste
below
10,000
Btu/
lb,
those
that
burn
hazardous
waste
with
a
heating
value
of
10,000
Btu/
lb
or
greater.
See
Part
Four,
Section
VI.
D.
2
of
today's
preamble
for
a
complete
discussion.
The
additional
changes
to
the
liquid
fuel
boiler
standards
for
existing
sources
since
proposal
are:
Final
Limit
Standard
Proposed
Limit
HW
Fuel
<
10,000
Btu/
lb
HW
Fuel
>
10,000
Btu/
lb
Mercury
(
lb/
MM
Btu)
3.7E­
6
19
ug/
dscm
4.2E­
5
Particulate
matter
(
gr/
dscf)
0.032
0.035
Semivolatile
metals
(
lb/
MM
Btu)
1.1E­
5
150
ug/
dscm
8.2E­
5
Chromium
(
lb/
MM
Btu)
1.1E­
4
370
ug/
dscm
1.3E­
4
Total
chlorine
(
Lb/
MM
Btu)
2.5E­
2
31
ppmv
5.1E­
2
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
lead,
cadmium
and
selenium
(
lb/
MM
Btu)
1.1E­
5
150
ug/
dscm
8.2E­
5
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
arsenic,
beryllium,
chromium,
antimony,
cobalt,
manganese,
and
nickel
(
lb/
MM
Btu)
1.1E­
4
370
ug/
dscm
1.3E­
4
The
changes
in
the
liquid
fuel
boiler
standards
for
new
sources
since
proposal
are:

Final
Limit
Standard
Proposed
Limit
HW
Fuel
<
10,000
Btu/
lb
HW
Fuel
>
10,000
Btu/
lb
Dioxin
and
Furan,
dry
APCD
(
ng
TEQ/
dscm)
0.015
or
temp
control
<
400F
for
dry
APCD
0.40
Mercury
(
lb/
MM
Btu)
3.8E­
7
6.8
ug/
dscm
1.2E­
6
Particulate
matter
(
gr/
dscf)
0.0076
0.0087
Semivolatile
metals
(
lb/
MM
Btu)
4.3E­
6
78
ug/
dscm
6.2E­
6
Chromium
(
lb/
MM
Btu)
3.6E­
5
12
ug/
dscm
1.4E­
5
Total
chlorine
(
lb/
MM
Btu)
7.2E­
4
31
ug/
dscm
5.1E­
2
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
lead,
cadmium
and
selenium
(
lb/
MM
Btu)
4.3E­
6
78
ug/
dscm1
6.2E­
61
Alternative
to
the
particulate
matter
standard:
Combined
emissions
of
arsenic,
beryllium,
chromium,
antimony,
cobalt,
manganese,
and
nickel
(
lb/
MM
Btu)
3.6E­
5
12
ug/
dscm2
1.4E­
52
1
New
or
reconstructed
liquid
fuel
boilers
that
process
residual
oil
or
liquid
feedstreams
that
are
neither
fossil
fuel
nor
hazardous
waste
and
that
operate
pursuant
to
the
alternative
to
the
particulate
matter
standard
must
comply
with
the
alternative
emission
concentration
standard
of
4.7
ug/
dscm,
which
is
applicable
to
lead,
cadmium
and
selenium
emissions
attributable
to
all
feedstreams
(
hazardous
and
nonhazardous).
2
New
or
reconstructed
liquid
fuel
boilers
that
process
residual
oil
or
liquid
feedstreams
that
are
neither
fossil
fuel
nor
hazardous
waste
that
operate
pursuant
to
the
alternative
to
the
particulate
matter
standard
must
comply
with
the
alternative
emission
concentration
standard
of
12
ug/
dscm,
which
is
applicable
to
arsenic,
beryllium,
chrome,
antimony,
cobalt,
manganese,
and
nickel
emissions
attributable
to
all
feedstreams
(
hazardous
and
nonhazardous).

F.
Hydrochloric
Acid
Production
Furnaces
The
changes
in
the
hydrochloric
acid
production
furnace
standards
for
existing
sources
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Dioxin
and
Furans
0.4
ng
TEQ/
dscm
Carbon
Monoxide/
Total
Hydrocarbons
and
DRE
standards
as
surrogates
Total
chlorine
14
ppmv
or
99.9927%
system
removal
efficiency
150
ppmv
or
99.923%
system
removal
efficiency
The
changes
in
the
hydrochloric
acid
production
furnace
standards
for
new
sources
since
proposal
are:

Standard
Proposed
Limit
Final
Limit
Dioxin
and
Furans
0.4
ng
TEQ/
dscm
Carbon
Monoxide/
Total
Hydrocarbons
and
DRE
standards
as
surrogates
Total
chlorine
1.2
ppmv
or
99.9994%
system
removal
efficiency
25
ppmv
or
99.987%
system
removal
efficiency
G.
Dioxin/
Furan
Testing
for
Sources
Not
Subject
to
a
Numerical
Standard
Today's
final
rule
requires
that
all
sources
not
subject
to
a
numerical
dioxin
and
furan
standard
perform
a
one
time
test
to
determine
their
dioxin
and
furan
emissions.
See
the
discussion
in
Part
Four,
Section
VII.
L.
In
the
proposed
rule,
this
requirement
was
limited
to
solid
fuel
boilers
and
those
liquid
fuel
boilers
with
a
wet
or
no
air
pollution
control
system.
The
final
rule
expands
this
requirement
to
include
hydrochloric
acid
production
furnaces
and
those
lightweight
aggregate
kilns
that
elect
to
comply
with
the
temperature
limit
at
the
kiln
exit
in
lieu
of
the
0.20
ng
TEQ/
dscm
dioxin/
furan
standard.
Those
sources
are
not
subject
to
a
numerical
dioxin/
furan
standard
under
the
final
rule
for
reasons
explained
in
Volume
III
of
the
Technical
Support
Document,
Sections
12
and
15.
We
note
that
sources
not
subject
to
a
numerical
dioxin/
furan
emission
standard
are
subject
to
the
carbon
monoxide
or
hydrocarbon
standards
and
the
DRE
standard
as
surrogates..
We
are
making
no
changes
to
the
implementation
of
this
requirement.
See
the
proposed
rule
at
69
FR
at
21307
for
more
information.
III.
Statistics
and
Variability
A.
Using
Statistical
Imputation
to
Address
Variability
of
Nondetect
Values
In
the
final
rule,
we
use
a
statistical
approach
to
impute
the
value
of
nondetect
emissions
and
feedrate
measurements
to
avoid
dampening
of
the
variability
of
data
sets
when
nondetect
measurements
are
assumed
to
be
present
at
the
detection
limit.
At
proposal,
we
assumed
that
nondetects
(
i.
e.,
HAP
levels
in
stack
emissions
below
the
level
of
detection
of
the
applicable
analytic
method)
are
invariably
present
at
the
detection
limit.
Commenters
on
the
proposed
rule
stated,
however,
that
assuming
nondetects
are
present
at
the
detection
limit
dampens
emissions
variability
 
a
consideration
necessary
to
reasonably
ascertain
sources'
performance
over
time.
This
could
have
significant
practical
consequence
for
those
data
sets
(
such
as
the
data
base
for
liquid
fuel
boilers)
dominated
by
nondetected
values.
We
agree
with
these
commenters,
and
instead
of
making
the
arbitrary
assumption
that
all
nondetected
values
are
identical
(
which
in
fact
is
highly
unlikely),
we
are
using
a
statistical
methodology
to
impute
the
value
of
nondetect
measurements.
The
imputation
approach
assigns
a
value
for
each
nondetect
measurement
in
a
data
set
within
the
possible
range
of
values
that
results
in
maximizing
the
99th
percentile
upper
prediction
limit
for
the
data
set.
For
example,
the
possible
range
of
values
for
a
measurement
that
is
100%
nondetect
is
between
zero
and
the
detection
limit.
On
February
4,
2005
we
distributed
a
direct
request
for
comments
on
the
imputation
approach
to
major
stakeholders.
We
respond
to
the
comments
we
received
in
Part
Four,
Section
IV.
D
of
today's
notice.

B.
Degrees
of
Freedom
when
Imputing
a
Standard
Deviation
Using
the
Universal
Variability
Factor
for
Particulate
Matter
Controlled
by
a
Fabric
Filter
The
use
of
the
universal
variability
factor
to
impute
a
standard
deviation
for
particulate
emissions
from
sources
controlled
with
a
fabric
filter
takes
advantage
of
the
empirical
observation
that
the
standard
deviation
of
particulate
emissions
from
sources
is
positively
correlated
to
the
average
particulate
emissions
of
sources.
Based
on
this
observation,
we
use
regression
analysis
to
determine
the
best
fitting
curve
to
explain
the
relationship
of
average
value
to
standard
deviation.
In
the
final
rule,
we
use
the
actual
sample
size,
rather
than
an
assumed
sample
size
of
nine
used
at
proposal,
to
determine
the
degrees
of
freedom
for
the
t­
statistic
to
calculate
the
floor
using
the
standard
deviation
imputed
from
the
universal
variability
factor
for
particulate
matter
controlled
by
a
fabric
filter.
At
proposal,
we
used
eight
degrees
of
freedom
to
identify
the
t­
statistic
to
account
for
within­
test
condition
variability
(
i.
e.,
run­
to­
run
variability)
for
standard
deviations
imputed
from
the
universal
variability
factor
regression.
28
This
is
because,
on
average,
about
three
test
conditions
with
nine
individual
test
runs
are
associated
with
each
source
used
to
develop
the
regression
curve.
A
commenter
states,
however,
that
this
approach
can
dramatically
understate
variability
when
imputing
a
standard
deviation
for
a
source
with
only
three
runs
because
the
t­
statistic
is
substantially
higher
for
2
degrees
of
freedom
than
8
degrees
of
freedom.

28
USEPA,
"
Draft
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
March
2004,
p.
5­
4.
We
agree
with
the
commenter.
Moreover,
using
the
actual
number
of
runs
to
identify
the
t­
statistic
rather
than
assuming
nine
runs
is
appropriate
given
that
the
true
test
condition
average
is
less
certain
for
sources
with
only
three
runs,
and
thus
there
is
less
certainty
in
the
imputed
standard
deviation.
The
higher
t­
statistic
associated
with
a
three­
run
data
set
reflects
this
uncertainty.
In
addition,
we
include
emissions
data
classified
as
"
normal"
in
the
regression
analysis
for
the
final
rule.
At
proposal,
we
used
only
data
classified
as
CT
(
i.
e.,
highest
compliance
test
condition
in
a
test
campaign)
or
IB
(
i.
e.,
a
compliance
test
condition
that
achieved
lower
emissions
than
another
compliance
test
condition
in
the
test
campaign).
We
conclude
that
normal
data
(
i.
e.,
emissions
data
that
were
not
used
to
establish
operating
limits
and
thus
do
not
reflect
variability
in
controllable
operating
parameters)
should
also
be
considered
in
the
regression
analysis
because
particulate
matter
emissions
are
relatively
insensitive
to
baghouse
inlet
loading
and
operating
conditions.
29
Including
normal
emissions
in
the
analysis
provides
additional
data
to
better
quantify
these
devices'
performance
variability.

IV.
Compliance
Assurance
for
Fabric
Filters,
Electrostatic
Precipitators,
and
Ionizing
Wet
Scrubbers
The
final
rule
provides
additional
requirements
to
clarify
how
you
determine
the
duration
of
periods
of
operation
when
the
alarm
set
point
has
been
exceeded
for
a
bag
leak
detection
system
or
a
particulate
matter
detection
system:
1.
You
must
keep
records
of
the
date,
time,
and
duration
of
each
alarm,
the
time
corrective
action
was
initiated
and
completed,
and
a
brief
description
of
the
cause
of
the
alarm
and
the
corrective
action
taken.
2.
You
must
record
the
percent
of
the
operating
time
during
each
6­
month
period
that
the
alarm
sounds.
3.
In
calculating
the
operating
time
percentage,
if
inspection
of
the
fabric
filter,
electrostatic
precipitator,
or
ionizing
wet
scrubber
demonstrates
that
no
corrective
action
is
required,
no
alarm
time
is
counted.
4.
If
corrective
action
is
required,
each
alarm
shall
be
counted
as
a
minimum
of
1
hour.
The
final
rule
also
establishes
revised
procedures
for
establishing
the
alarm
set
point
if
you
elect
to
use
a
particulate
matter
detector
system
in
lieu
of
site­
specific
operating
parameter
limits
for
compliance
assurance
for
sources
equipped
with
electrostatic
precipitators
and
ionizing
wet
scrubbers.
The
rule
explicitly
allows
you
to
maximize
controllable
operating
parameters
during
the
comprehensive
performance
test
to
account
for
variability
by,
for
example,
detuning
the
APCD
or
spiking
ash.
To
establish
the
alarm
setpoint
you
may
either
establish
the
set­
point
as
the
average
of
the
test
condition
run
average
detector
responses
during
the
comprehensive
performance
test
or
extrapolate
the
detector
response
after
approximating
the
correlation
between
the
detector
response
and
particulate
matter
emission
concentrations.
You
may
extrapolate
the
detector
response
up
to
a
response
value
that
corresponds
to
50%
of
the
particulate
matter
emission
standard
or
125%
of
the
highest
particulate
matter
concentration
used
to
develop
the
correlation,
whichever
is
greater.
To
establish
an
approximate
correlation
of
the
detector
response
to
particulate
matter
emission
concentrations
you
should
use
as
guidance
Performance
Specification­
11
for
PM
29
USEPA,
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
5.3.
See
also
Part
Four,
Section
III.
C
of
this
preamble.
CEMS
(
40
CFR
Part
60,
Appendix
B),
except
that
you
need
conduct
only
5
runs
to
establish
the
initial
correlation
rather
than
a
minimum
of
15
runs
required
by
PS­
11.
The
final
rule
also
notes
that
an
exceedance
of
a
detector
response
that
corresponds
to
the
particulate
matter
emission
standard
is
not
evidence
that
the
standard
has
been
exceeded
because
the
correlation
is
an
approximate
correlation
used
for
the
purpose
of
compliance
assurance
to
determine
when
corrective
measures
must
be
taken.
The
correlation,
however,
does
not
meet
the
requirements
of
PS­
11
for
compliance
monitoring.
In
addition,
if
you
elect
to
use
a
particulate
matter
detection
system
in
lieu
of
sitespecific
control
device
operating
parameter
limits
on
the
electronic
control
device,
the
ash
feedrate
limit
for
incinerators
and
boilers
under
§
63.1209(
m)(
3)
is
waived.
The
ash
feedrate
limit
is
waived
because
the
particulate
matter
detection
system
continuously
monitors
relative
particulate
matter
emissions
and
the
alarm
set
point
provides
reasonable
assurance
that
emissions
will
not
exceed
the
standard.
30
Finally,
you
must
submit
an
excessive
exceedance
notification
within
30
days
of
the
date
that
the
alarm
set­
point
is
exceeded
more
than
5
percent
of
the
time
during
any
6­
month
block
period
of
time,
or
within
30
days
after
the
end
of
the
6­
month
block
period,
whichever
is
earlier.
The
proposed
rule
would
have
required
you
to
submit
that
notification
within
5
days
of
the
end
of
the
6­
month
block
period.

V.
Health­
Based
Compliance
Alternative
for
Total
Chlorine
The
final
rule
includes
the
following
major
changes
to
the
proposed
health­
based
compliance
alternative
for
total
chlorine:
(
1)
You
must
use
1­
hour
Reference
Exposure
Levels
(
aRELs)
rather
than
1­
hour
acute
exposure
guideline
levels
(
AEGL­
1)
as
the
acute
health
risk
threshold
metric
when
calculating
1­
hour
HCl­
equivalent
emission
rates;
(
2)
You
must
establish
a
long­
term
average
chlorine
feedrate
limit
(
i.
e.,
12
hour
rolling
average
or
an
(
up
to)
annual
rolling
average)
as
the
annual
average
HCl­
equivalent
emission
rate
limit
divided
by
[
1
 
system
removal
efficiency].
You
establish
the
total
chlorine
system
removal
efficiency
during
the
comprehensive
performance
test.
The
proposed
rule
would
have
required
you
to
establish
the
long­
term
average
chlorine
feedrate
limit
as
the
average
of
the
test
run
averages
of
the
comprehensive
performance
test.
31
(
3)
At
proposal,
we
requested
comment
on
whether
and
how
to
establish
a
short­
term
chlorine
feedrate
limit
to
ensure
that
the
acute
exposure
Hazard
Index
of
1.0
is
not
exceeded.
See
69
FR
at
21304.
We
conclude
for
the
final
rule
that
a
1­
hour
rolling
average
feedrate
30
Note
that
if
your
incinerator
or
boiler
is
equipped
with
a
fabric
filter
and
you
elect
under
§
63.1206(
c)(
8)(
i)
to
use
a
particulate
matter
detection
system
in
lieu
of
a
bag
leak
detection
system
for
compliance
assurance,
the
ash
feedrate
limit
is
waived.
The
ash
feedrate
limit
is
not
waived
if
you
use
a
bag
leak
detection
system,
however,
because
the
alarm
level
may
not
ensure
compliance
with
the
emission
standard
when
you
follow
the
concepts
in
the
Agency's
guidance
document
on
bag
leak
detection
systems
to
establish
the
alarm
level.
31
Note
that,
as
a
practical
matter,
most
sources
must
establish
the
chlorine
feedrate
limit
as
the
average
of
the
test
run
average
feedrate
limit
during
the
comprehensive
performance
test
to
demonstrate
compliance
with
the
semivolatile
emission
standard.
This
is
because
chlorine
feedrate
is
a
compliance
assurance
parameter
for
the
semivolatile
metal
emission
standard.
That
feedrate
limit
is
based
on
a
12­
hour
rolling
average.
To
ensure
compliance
with
the
annual
average
HCl­
equivalent
emission
rate
limit,
however,
that
feedrate
limit
cannot
exceed
the
value
calculated
as
the
annual
average
HCl­
equivalent
emission
rate
limit
divided
by
[
1
 
system
removal
efficiency],
where
you
demonstrate
the
total
chlorine
system
removal
efficiency
during
the
performance
test.
limit
may
be
needed
for
some
situations
(
i.
e.,
if
chlorine
feedrates
can
vary
substantially
during
the
averaging
period
for
the
long­
term
feedrate
limit
and
potentially
result
in
an
exceedance
of
the
1­
hour
average
HCl­
equivalent
emission
rate
limit).
Accordingly,
although
your
eligibility
for
the
health­
based
compliance
alternatives
is
based
on
annual
average
HCl­
equivalent
emissions,
you
must
determine
considering
prescribed
criteria
whether
your
1­
hour
HCl­
equivalent
emission
rate
may
exceed
the
national
exposure
standard
(
i.
e.,
Hazard
Index
not
exceeding
1.0
considering
the
maximum
1­
hour
average
ambient
concentration
of
hydrogen
chloride
and
chlorine
at
an
off­
site
receptor
location32)
and
thus
may
exceed
the
1­
hour
average
HCl­
equivalent
emission
rate
limit
absent
an
hourly
rolling
average
limit
on
the
feedrate
of
chlorine.
If
the
acute
exposure
standard
may
be
exceeded,
you
must
establish
an
hourly
rolling
average
chlorine
feedrate
limit
as
the
1­
hour
HCl­
equivalent
emission
rate
limit
divided
by
[
1
 
system
removal
efficiency].
You
establish
the
system
removal
efficiency
during
the
comprehensive
performance
test.
(
4)
When
calculating
HCl­
equivalent
emission
rates,
rather
than
partitioning
total
chlorine
emissions
between
chlorine
and
HCl
(
i.
e.,
the
Cl2/
HCl
volumetric
ratio)
based
on
the
comprehensive
performance
test
as
proposed,
you
must
establish
the
Cl2/
HCl
volumetric
ratio
used
to
calculate
the
annual
average
HCl­
equivalent
emission
rate
based
on
the
historical
average
ratio
from
all
regulatory
compliance
tests.
You
must
establish
the
Cl2/
HCl
volumetric
used
to
calculate
the
1­
hour
average
HCl­
equivalent
emission
rate
as
the
highest
of
the
historical
ratios
from
all
regulatory
compliance
tests.
The
rule
allows
you
to
exclude
ratios
from
historical
compliance
tests
where
the
emission
data
may
not
be
representative
of
the
current
Cl2/
HCl
ratio
for
reasons
such
as
changes
to
the
design
or
operation
of
the
combustor
or
biases
in
measurement
methods.
The
rule
also
explicitly
allows
the
permitting
authority
to
require
periodic
emissions
testing
to
obtain
a
representative
average
and
maximum
ratio;
(
5)
The
look­
up
table
analysis
has
been
refined
by
presenting
annual
average
and
1­
hour
HCl­
equivalent
emission
rate
limits
as
a
function
of
stack
height,
stack
diameter,
and
distance
to
property
line.
In
addition,
separate
look­
up
tables
are
presented
for
flat
terrain
and
simple
elevated
terrain;
(
6)
The
proposed
rule
required
approval
of
the
eligibility
demonstration
before
you
could
comply
with
the
alternative
health­
based
emission
limits
for
total
chlorine.
Under
the
final
rule,
if
your
permitting
authority
has
not
approved
your
eligibility
demonstration
by
the
compliance
date,
and
has
not
issued
a
notice
of
intent
to
disapprove
your
demonstration,
you
may
nonetheless
begin
complying,
on
the
compliance
date,
with
the
annual
average
HClequivalent
emission
rate
limits
you
present
in
your
eligibility
demonstration.
In
addition,
if
your
permitting
authority
issues
a
notice
of
intent
to
disapprove
your
eligibility
demonstration,
the
authority
will
identify
the
basis
for
that
notice
and
specify
how
much
time
you
will
have
to
submit
additional
information
or
to
comply
with
the
MACT
total
chlorine
standards.
The
permitting
authority
may
extend
the
compliance
date
of
the
total
chlorine
standards
to
allow
you
to
make
changes
to
the
design
or
operation
of
the
combustor
or
related
systems
as
quickly
as
practicable
to
enable
you
to
achieve
compliance
with
the
MACT
total
chlorine
standards;
(
7)
We
have
revised
the
approach
for
determining
chlorine
emissions
if
you
feed
bromine
or
sulfur
during
the
comprehensive
performance
test
at
levels
higher
than
those
32
Under
the
site­
specific
risk
assessment
approach
to
demonstrate
eligibility,
you
must
consider
locations
where
people
reside
and
where
people
congregate
for
work,
school,
or
recreation.
specified
in
§
63.1215(
e)(
3)(
ii)(
B).
Under
the
final
rule,
you
must
use
EPA
Method
320/
321
or
ASTM
D
6735
 
01,
or
an
equivalent
method,
to
measure
hydrogen
chloride,
and
Method
26/
26A,
or
an
equivalent
method,
to
measure
chlorine
and
hydrogen
chloride.
You
must
determine
your
chlorine
emissions
to
be
the
higher
of:
(
1)
the
value
measured
by
Method
26/
26A,
or
an
equivalent
method;
or
(
2)
the
value
calculated
by
difference
between
the
combined
hydrogen
chloride
and
chlorine
levels
measured
by
Method
26/
26a,
or
an
equivalent
method,
and
the
hydrogen
chloride
measurement
from
EPA
Method
320/
321
or
ASTM
D
6735­
01,
or
an
equivalent
method;
and
(
8)
The
proposed
rule
would
have
required
you
to
conduct
a
new
comprehensive
performance
test
if
you
planned
to
make
changes
to
the
facility
that
would
lower
the
annual
average
HCl­
equivalent
emission
rate
limit.
Under
the
final
rule,
you
would
be
required
to
conduct
a
performance
test
as
a
result
of
a
planned
change
only
for
a
change
to
the
design,
operation,
or
maintenance
of
the
combustor
that
could
affect
the
system
removal
efficiency
for
total
chlorine
if
the
change
could
reduce
the
system
removal
efficiency,
or
if
the
change
would
increase
the
system
removal
efficiency
and
you
elect
to
increase
the
feedrate
limits
on
total
chlorine
and
chloride.

Part
Four:
What
Are
the
Responses
to
Major
Comments?

I.
Database
A.
Revisions
to
the
EPA's
Hazardous
Waste
Combustor
Data
Base
Comment:
Several
commenters
identify
sources
which
have
ceased
operations
as
a
hazardous
waste
combustor
and
should
be
removed
from
EPA's
data
base.
Response:
We
agree
with
commenters
that
data
and
information
from
sources
no
longer
burning
hazardous
waste
should
not
be
included
in
our
hazardous
waste
combustor
data
base
and
should
not
be
used
to
calculate
the
MACT
standards.
We
consider
any
source
that
has
initiated
RCRA
closure
procedures
and
activities
as
a
source
that
is
no
longer
burning
hazardous
waste.
This
data
handling
decision
is
consistent
with
the
approach
we
used
in
the
1999
final
rule.
See
64
FR
at
52844.
As
we
stated
in
that
rule,
ample
emissions
data
remain
to
support
calculating
the
MACT
standards
without
using
data
from
sources
that
no
longer
burn
hazardous
waste.
As
a
result,
we
removed
the
following
former
hazardous
waste
combustors
from
the
data
base:
the
Safety­
Kleen
incinerator
in
Clarence,
New
York,
the
Dow
Chemical
Company
incinerators
in
Midland,
Michigan,
and
LaPorte,
Texas,
the
two
Holcim
wet
process
cement
kilns
in
Holly
Hill,
South
Carolina,
the
Dow
Chemical
Company
liquid
fuel­
fired
boiler
in
Freeport,
Texas,
the
Union
Carbide
liquid
fuel­
fired
boilers
in
Hahnville,
Louisiana,
and
Texas
City,
Texas,
and
six
Dow
Chemical
Company
hydrochloric
production
furnaces
in
Freeport,
Texas.
We
are
retaining,
however,
Solite
Corporation's
lightweight
aggregate
facility
in
Cascade,
Virginia,
in
the
data
base.
Even
though
the
facility
recently
initiated
RCRA
closure
procedures,
this
data
handling
decision
differs
from
those
listed
in
the
preceding
paragraph
because
Solite
Corporation
provided
this
new
information
in
February
2005
while
information
on
the
other
closures
was
reported
or
available
to
us
in
2004.
Because
we
cannot
continually
adjust
our
data
base
and
still
finalize
this
rulemaking
by
the
court­
ordered
deadline,
we
stopped
making
revisions
to
the
data
base
in
late
2004.
Additional
facility
changes
after
that
date,
like
Solite
Corporation's
Cascade
facility
closure,
simply
could
not
be
incorporated.
Comment:
One
commenter
identifies
a
source
in
EPA's
data
base
that
should
be
classified
as
a
boiler
instead
of
a
hydrochloric
acid
production
furnace.
Response:
We
agree
with
the
commenter.
In
today's
rule,
Dow
Chemical
Company's
boiler
F­
2820,
located
in
Freeport,
Texas,
is
reclassified
in
our
data
base
as
a
boiler.
This
source
is
identified
as
unit
number
2020
in
our
data
base.

B.
Use
of
Data
from
Recently
Upgraded
Sources
Comment:
Many
commenters
recommend
that
EPA
remove
from
the
data
base
(
or
not
consider
for
standards­
setting
purposes)
emissions
data
from
sources
that
upgraded
their
emissions
controls
to
comply
with
the
promulgated
emission
standards
of
either
the
1999
rule
or
the
2002
interim
standards.
Several
commenters
also
state
that
any
emissions
data
that
were
obtained
or
used
to
demonstrate
compliance
with
the
promulgated
standards
of
1999
or
2002
should
not
be
used
for
standard­
setting
purposes
by
the
Agency.
That
is,
EPA
must
evaluate
the
source
category
as
it
existed
at
the
beginning
of
the
rule
development
process
and
not
after
emissions
controls
are
later
added
to
comply
with
the
1999
or
2002
standards.
Several
commenters
also
state
that
EPA
is
only
partly
correct
in
claiming
that
the
interim
standards
are
not
MACT
standards
because
the
interim
standards
were
established
and
considered
to
be
MACT
until
the
Court
issued
its
opinion
in
July
2001.
Until
that
time,
sources
proceeded
to
upgrade
their
facilities
to
achieve
the
standards
promulgated
in
1999.
The
rationale
for
these
recommendations
is
threefold:
(
1)
use
of
the
data
unfairly
ignores
the
MACT­
driven
reductions
already
achieved
by
some
sources;
(
2)
it
is
contrary
to
sound
public
policy
to
use
data
from
upgraded
facilities
to
"
ratchet
down"
the
MACT
floors
to
a
level
more
stringent
because
these
sources
would
not
have
increased
their
level
of
performance
but
for
the
legal
obligation
to
comply
with
the
standards;
and
(
3)
EPA's
reliance
on
National
Lime
Ass'n
v.
EPA,
233
F.
3d
625,
640
(
D.
C.
Cir.
2000),
for
the
proposition
that
the
motivation
for
a
source's
performance
is
legally
irrelevant
in
developing
MACT
floor
levels
is
misplaced
because
that
case
involved
the
initial
MACT
standard
setting
process,
and
not
a
subsequent
rule.
One
commenter
agrees
with
EPA's
proposed
position
and
states
that
use
of
data
from
sources
that
have
upgraded
is
not
only
appropriate,
but
also
required
by
the
Clean
Air
Act.
This
commenter
states
that
the
actual
performance
of
sources
that
have
upgraded
their
emissions
equipment
 
to
meet
the
1999
standards
or
for
any
reason
 
is
reflected
only
by
the
most
recently
generated
emissions
data
for
the
source.
Thus,
the
Clean
Air
Act
requires
EPA
to
use
the
most
recently
generated
data
available
to
it
and
precludes
the
Agency
from
using
older,
out­
of­
date
performance
data.
EPA
also
received
several
comments
stating
that
the
language
of
section
112(
d)(
3)(
A)
of
the
Clean
Air
Act
informs
how
the
Agency
should
consider
emissions
data
from
sources
that
conducted
testing
after
that
1999
rule
was
promulgated.
One
commenter
states
that
the
only
data
which
should
not
be
used
in
calculating
the
MACT
floors
are
from
sources
that
are
subject
to
lowest
achievable
emission
rates
(
LAER).
Thus,
the
commenter
states,
Congress
considered
the
possibility
of
significant
and
recent
upgrades,
and
concluded
that
EPA
should
use
up­
to­
date
data
to
reflect
source's
performance,
but
must
exclude
certain
sources
from
the
floor
calculation
if
their
upgrades
were
of
a
specific
degree
and
were
accomplished
within
a
specific
period
of
time.
Another
commenter
states
that
Congress
did
not
intend
to
pile
technology
upon
technology
as
confirmed
by
section
112(
d)(
3)(
A)
that
specifically
excludes
sources
that
implemented
LAER
from
consideration
when
establishing
section
112(
d)
standards.
Thus,
the
commenter
states,
considering
data
from
sources
that
have
upgraded
violates
both
the
language
and
intent
of
the
Clean
Air
Act.
Another
commenter
states
that,
while
Congress
no
doubt
contemplated
that
EPA
should
use
all
available
emissions
information
in
setting
initial
MACT
standards,
neither
the
statute
nor
the
legislative
history
suggest
that
follow­
up
MACT
rulemakings
require
the
use
of
data
reflecting
compliance
efforts
with
previous
MACT
standards
or
interim
standards.
Response:
As
proposed,
EPA
maintains
its
position
on
use
of
post­
1999
emissions
data.
The
statute
indicates
that
EPA
is
to
base
MACT
floors
on
performance
of
sources
"
for
which
the
Administrator
has
emissions
information."
Section
112(
d)(
3)(
A);
CKRC,
255
F.
3d
at
867.
There
can
be
no
dispute
that
post­
1999
performance
data
in
EPA's
possession
fits
this
description.
We
also
reiterate
that
the
motivation
for
the
control
reflected
in
data
available
to
us
is
irrelevant.
See
69
FR
at
21217­
218.
We
further
agree
with
those
commenters
who
pointed
out
that
Congress
was
explicit
when
it
wanted
certain
emissions
information
(
i.
e.,
sources
operating
pursuant
to
a
LAER
standard)
excluded
from
consideration
in
establishing
floors.
There
is,
of
course,
no
such
enumerated
exception
for
sources
that
have
upgraded
their
performance
for
other
reasons.
We
also
do
not
agree
with
those
commenters
arguing
(
with
respect
to
the
standards
for
the
Phase
1
sources
(
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns))
in
effect
that
the
present
rulemaking
involves
revision
of
an
existing
MACT
standard.
If
this
were
indeed
a
revision
of
a
MACT
standard
under
section
112(
d)(
6),
then
EPA
would
not
redetermine
floor
levels.
See
70
FR
at
20008
(
April
15,
2005).
However,
EPA
has
not
to
date
promulgated
valid
MACT
floors
or
valid
MACT
standards
for
these
sources.
The
1999
standards
do
not
reflect
MACT,
as
held
by
the
CKRC
court.
The
interim
standards
likewise
do
not
reflect
MACT,
but
were
designed
to
prevent
a
regulatory
gap
and
were
described
as
such
from
their
inception.
67
FR
at
7693
(
Feb.
13,
2002);
see
also
Joint
Motion
of
all
Parties
for
Stay
of
Issuance
of
Mandate
in
case
no.
99­
1457
(
October
19,
2001),
pp.
11­
12
("
The
Parties
emphasize
that
the
contemplated
interim
rule
is
in
the
nature
of
a
remedy.
It
would
not
respond
to
the
Court's
mandate
regarding
the
need
to
demonstrate
that
EPA's
methodology
reasonably
predicts
the
performance
of
the
average
of
the
best
performing
twelve
percent
of
sources
(
or
best­
performing
source).
EPA
intends
to
address
those
issues
in
a
subsequent
rule,
which
will
necessarily
require
a
longer
time
to
develop,
propose,
and
finalize.")
EPA
consequently
believes
that
it
is
adopting
in
this
rule
the
initial
section
112(
d)
MACT
standards
for
hazardous
waste
burning
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns,
and
that
the
floor
levels
for
existing
sources
are
based,
as
provided
in
section
112(
d)(
3),
on
performance
of
those
sources
for
which
EPA
has
"
emissions
information."
However,
we
disagree
with
the
comment
that
we
must
make
exclusive
use
of
the
most
recent
information
from
hazardous
waste
combustion
sources.
There
is
no
such
restriction
in
section
112(
d)(
3).
EPA
has
exhaustively
examined
all
of
the
data
in
its
possession
for
all
source
categories
covered
by
this
rule,
and
determined
(
and
documented)
which
data
are
suitable
for
evaluating
sources'
performance.
C.
Correction
of
Total
Chlorine
Data
to
Address
Potential
Bias
in
Stack
Measurement
Method
Comment:
Several
commenters
state
that
EPA's
proposed
total
chlorine
standards
of
1.5
ppm
for
existing
incinerators
and
0.18
ppm
for
new
incinerators
are
based
on
biased
data
of
indeterminate
quality
and
are
unachievable.
Commenters
assert
that
Method
26A
and
its
RCRA
equivalent,
SW
846
Method
0050,
have
a
negative
bias
at
concentrations
below
20
ppmv
when
used
on
stacks
controlled
with
wet
scrubbers.
Commenters
cite
two
recurring
situations
when
this
bias
is
likely
to
occur:
(
1)
hydrogen
chloride
dissolving
in
condensed
moisture
in
the
sampling
train;
and
(
2)
hydrogen
chloride
reacting
with
alkaline
compounds
from
the
scrubber
water
that
are
collected
on
the
filter
ahead
of
the
impingers.
Commenters
are
particularly
concerned
about
the
negative
bias
associated
with
stack
gas
containing
substantial
water
vapor.
Commenters
note
that
EPA
found
in
a
controlled
laboratory
study
by
Steger33
that
the
bias
is
between
17
and
29
percent
at
stack
gas
moisture
content
of
7
to
9
percent.
This
stack
gas
moisture
is
much
less
than
the
nominal
50%
moisture
contained
in
some
hazardous
waste
combustor
stacks
according
to
the
commenters.
Commenters
believe
this
is
why
EPA's
Method
0050,
which
was
used
to
gather
most
of
the
data
in
the
HWC
MACT
data
base,
states
in
Section
1.2
that
"
this
method
is
not
acceptable
for
demonstrating
compliance
with
HCl
emission
standards
less
than
20
ppm."
Moreover,
commenters
state
that
the
procedures
in
Method
0050
to
address
the
negative
bias
caused
by
condensed
moisture
were
not
followed
for
many
RCRA
compliance
tests.
The
method
uses
an
optional
cyclone
to
collect
moisture
droplets,
and
requires
a
45
minute
purge
of
the
cyclone
and
sampling
train
to
recover
hydrogen
chloride
from
water
collected
by
the
cyclone
and
any
condensed
moisture
in
the
train.
The
cyclone
is
not
necessary
if
the
stack
gas
does
not
contain
water
droplets.
According
to
commenters,
the
cyclone
and
subsequent
purge
were
often
not
used
in
the
presence
of
water
droplets
because
a
potential
low
bias
below
20
ppmv
was
irrelevant
when
demonstrating
compliance
with
emission
standards
on
the
order
of
100
ppmv.
There
was
no
need
for
the
extra
complexity
and
expense
of
using
a
cyclone
and
train
purge
given
the
purpose
of
the
test.
Although
the
data
were
acceptable
for
their
intended
purpose,
commenters
conclude
that
the
data
are
not
useful
for
establishing
standards
below
20
ppmv.
For
these
reasons,
commenters
suggest
that
EPA
not
consider
total
chlorine
measurements
below
20
ppmv
when
establishing
the
standards.
Response:
For
the
reasons
discussed
below,
we
corrected
all
total
chlorine
measurements
in
our
data
base
for
all
source
categories
that
were
below
20
ppmv
to
20
ppmv
to
establish
the
total
chlorine
floors.
Moreover,
to
address
run­
to­
run
variability
given
that
all
runs
for
several
data
sets
are
now
corrected
to
20
ppmv,
we
impute
a
run
standard
deviation
based
on
a
regression
analysis
of
run
standard
deviation
versus
total
chlorine
concentration
for
sources
with
total
chlorine
measurements
greater
than
20
ppmv.
This
is
the
same
approach
we
used
to
impute
variability
from
sources
using
fabric
filters
when
determining
the
particulate
matter
MACT
floors.
Effect
of
Moisture
Vapor.
Commenters
imply
that
stack
gas
with
high
levels
of
gas
phase
water
vapor
will
inherently
be
problematic,
particularly
at
emissions
less
than
20
ppmv.
There
is
no
basis
for
claiming
that
water
vapor,
per
se,
causes
a
bias
in
SW­
846
33
Steger,
J.
L.,
et
al,
"
Laboratory
Evaluation
of
Method
0050
for
Hydrogen
Chloride",
Proc
of
13th
Annual
Incineration
Conference,
Houston,
TX,
May
1994.
Method
0050
or
its
equivalent,
Method
26A.
Condensed
moisture
(
i.
e.,
water
droplets),
however,
can
cause
a
bias
because
it
can
dissolve
hydrogen
chloride
in
the
sampling
train
and
prevent
it
from
being
captured
in
the
impingers
if
the
sampling
train
is
not
properly
purged.
Water
droplets
can
potentially
be
present
due
to
entrainment
from
the
wet
scrubber,
condensation
in
cooler
regions
of
the
stack
along
the
stack
walls,
and
entrainment
from
condensed
moisture
dripping
down
the
stack
wall
across
the
inlet
duct
opening.
Although
Method
0050
addresses
the
water
droplet
issue
by
use
of
a
cyclone
and
45
minute
purge,
the
Steger
paper
(
Ibid.)
concludes
that
a
45
minute
purge
is
not
adequate
to
evaporate
all
water
collected
by
the
cyclone
in
stacks
with
a
total
moisture
content
(
vapor
and
condensed
moisture)
of
7
to
9%.
At
those
moisture
levels,
Steger
documented
the
negative
bias
that
commenters
reference.
Steger's
recommendation
was
to
increase
the
heat
input
to
the
sample
train
by
increasing
the
train
and
filter
temperature
from
120C
(
248F)
to
200C
(
392F).
We
agree
that
increasing
the
probe
and
filter
temperature
will
provide
a
better
opportunity
to
evaporate
any
condensed
moisture,
but
another
solution
to
the
problem
is
to
require
that
the
post­
test
purge
be
run
long
enough
to
evaporate
all
condensed
moisture.
That
is
the
approach
used
by
Method
26A,
which
EPA
promulgated
after
Method
0050,
and
which
sources
must
use
to
demonstrate
compliance
with
the
final
standards.
Method
26A
uses
an
extended
purge
time
rather
than
elevating
the
train
temperature
to
address
condensed
moisture
because
that
approach
can
be
implemented
by
the
stack
tester
at
the
site
without
using
nonstandard
equipment.
We
attempted
to
quantify
the
level
of
condensed
moisture
in
the
Steger
study
and
to
compare
it
to
the
levels
of
condensed
moisture
that
may
be
present
in
hazardous
waste
combustor
stack
gas.
This
would
provide
an
indication
if
the
bias
that
Steger
quantified
with
a
45
minute
purge
might
also
be
applicable
to
some
hazardous
waste
combustors.
We
conclude
that
this
comparison
would
be
problematic,
however,
because:
(
1)
given
the
limited
information
available
in
the
Steger
paper,
it
is
difficult
to
quantify
the
level
of
condensed
moisture
in
his
gas
samples;
and
(
2)
we
cannot
estimate
the
levels
of
condensed
moisture
in
hazardous
waste
combustor
stack
gas
because,
even
though
condensed
moisture
may
have
been
present
during
a
test,
method
protocol
is
to
report
the
saturation
moisture
level
only
(
i.
e.,
the
amount
of
water
vapor
present),
and
not
the
total
moisture
content
(
i.
e.,
both
condensed
and
vapor
phase
moisture).
We
can
conclude,
however,
that,
if
hazardous
waste
combustor
stack
gas
were
to
contain
the
levels
of
condensed
moisture
present
in
the
gas
that
Steger
tested,
the
45
minute
purge
required
by
Method
0050
would
not
be
sufficient
to
avoid
a
negative
bias.
We
also
conclude
that
this
is
potentially
a
practical
issue
and
not
merely
a
theoretical
concern
because,
as
commenters
note,
hazardous
waste
combustors
that
use
wet
scrubbers
are
often
saturated
with
water
vapor
that
will
condense
if
the
flue
gas
cools.
Data
from
Wet
Stacks
When
a
Cyclone
Was
Not
Used.
Commenters
state
that
Method
0050
procedures
for
addressing
water
droplets
(
adequate
or
not,
as
discussed
above)
were
not
followed
in
many
cases
because
a
low
bias
below
20
ppmv
was
not
relevant
to
demonstrating
compliance
with
standards
on
the
order
of
100
ppmv.
We
do
not
know
which
data
sets
may
be
problematic
because,
as
previously
stated,
the
moisture
concentration
reported
was
often
the
saturation
(
vapor
phase
only)
moisture
level
and
not
the
total
(
vapor
and
liquid)
moisture
in
the
flue
gas.
We
also
have
no
documentation
that
a
cyclone
was
used
 
even
in
situations
where
the
moisture
content
was
documented
to
be
above
the
dew
point.
We
therefore
conclude
that
all
data
below
20
ppmv
from
sources
controlled
with
a
wet
scrubber
are
suspect
and
should
be
corrected.
Potential
Bias
Due
to
Filter
Affinity
for
Hydrogen
Chloride.
Studies
by
the
American
Society
of
Testing
and
Materials
indicate
that
the
filter
used
in
the
Method
0050
train
(
and
the
M26/
26A
trains)
may
adsorb/
absorb
hydrogen
chloride
and
cause
a
negative
bias
at
low
emission
levels.
(
See
ASTM
D6735­
01,
section
11.1.3
and
"
note
2"
of
section
14.2.3)
This
inherent
affinity
for
hydrogen
chloride
can
be
satisfied
by
preconditioning
the
sampling
train
for
one
hour.
None
of
the
tests
in
our
database
were
preconditioned
in
such
a
manner.
We
are
normally
not
concerned
about
this
type
of
bias
because
we
would
expect
the
bias
to
apply
to
all
sources
equally
(
e.
g.,
wet
or
dry
gas)
and
for
all
subsequent
compliance
tests.
In
other
words,
we
are
ordinarily
less
concerned
if
a
standard
is
based
on
biased
data,
as
long
as
the
means
by
which
the
standard
was
developed
and
the
means
of
compliance
would
experience
identical
bias.
However,
we
did
correct
the
wet
gas
measurements
below
20
ppmv
to
address
the
potential
low
bias
caused
by
condensed
moisture.
This
correction
would
also
correct
for
any
potential
bias
caused
by
the
filter's
inherent
affinity
for
hydrogen
chloride.
This
results
in
a
data
set
that
is
partially
corrected
for
this
issue
 
sources
with
wet
stacks
would
be
corrected
for
this
potential
bias
while
sources
with
dry
stacks
would
not
be
corrected.
To
address
this
unacceptable
mix
of
potentially
biased
and
unbiased
data
(
i.
e.,
dry
gas
data
biased
due
to
affinity
of
filter
for
hydrogen
chloride
and
wet
gas
data
corrected
for
condensed
moisture
and
affinity
of
filter
for
hydrogen
chloride),
we
also
correct
total
chlorine
measurements
from
dry
gas
stacks
(
i.
e.,
sources
that
do
not
use
wet
scrubbers).
Deposition
of
Alkaline
Particulate
on
the
Filter.
Commenters
are
also
concerned
that
hydrogen
chloride
may
react
with
alkaline
compounds
from
the
scrubber
water
droplets
that
are
collected
on
the
filter
ahead
of
the
impingers.
Commenters
suggest
this
potential
cause
for
a
low
bias
at
total
chlorine
levels
below
20
ppmv
is
another
reason
not
to
use
measurements
below
20
ppmv
to
establish
the
standards.
Although
alkaline
particulate
deposition
on
the
method
filter
causing
a
negative
bias
is
a
much
greater
concern
for
sources
that
have
stack
gas
containing
high
levels
of
alkaline
particulate
(
e.
g.,
cement
kilns,
sources
equipped
with
dry
scrubbers),
we
agree
with
commenters
that
this
may
be
of
concern
for
all
sources
equipped
with
wet
scrubbers.
Our
approach
to
correct
all
data
below
20
ppmv
addresses
this
concern.
Decision
Unique
to
Hazardous
Waste
Combustors.
We
note
that
the
rationale
for
our
decision
to
correct
total
chlorine
data
below
20
ppmv
to
account
for
the
biases
discussed
above
is
unique
to
the
hazardous
waste
combustor
MACT
rule.
Some
sources
apparently
did
not
follow
Method
0050
procedures
to
minimize
the
low
bias
caused
by
condensed
moisture
for
understandable
reasons.
Even
if
sources
had
followed
Method
0050
procedures
to
minimize
the
bias
(
i.
e.,
cyclone
and
45
minute
purge)
there
still
may
have
been
a
substantial
bias
because
of
insufficient
purge
time,
as
Steger's
work
may
indicate.
We
note
that
the
total
chlorine
stack
test
method
used
by
sources
other
than
hazardous
waste
combustors
 
Method
26A
 
requires
that
the
cyclone
and
sampling
train
be
purged
until
all
condensed
moisture
is
evaporated.
We
believe
it
is
necessary
to
correct
our
data
below
20
ppmv
data
because
of
issues
associated
exclusively
with
Method
0050
and
how
it
was
used
to
demonstrate
compliance
with
these
sources.
Determining
Variability
for
Data
at
20
ppmv.
Correcting
those
total
chlorine
data
below
20
ppmv
to
20
ppmv
brings
about
a
situation
identical
to
the
one
we
confronted
with
nondetect
data.
See
Part
Four,
Section
V.
B.
below.
The
MACT
pool
of
best
performing
source(
s)
for
some
data
sets
is
now
comprised
of
largely
the
same
values.
This
has
the
effect
of
understating
the
variability
associated
with
these
data.
To
address
this
concern,
we
took
an
approach
similar
to
the
one
we
used
to
determine
variability
of
PM
emissions
for
sources
equipped
with
a
fabric
filter.
In
that
case,
we
performed
a
linear
regression
on
the
data,
charting
variability
against
emissions,
and
used
the
variability
that
resulted
from
the
linear
regression
analysis
as
the
variability
for
the
sources
average
emissions.
In
this
case,
most
or
all
of
the
incinerator
and
liquid
fuel
boiler
sources
in
the
MACT
pool
have
average
emissions
at
or
near
20
ppmv.
We
therefore
performed
a
linear
regression
on
the
total
chlorine
data
charting
average
test
condition
results
above
20
ppmv
against
the
variability
associated
with
that
test
condition.
The
variability
associated
with
20
ppmv
was
the
variability
we
used
for
incinerator
and
liquid
fuel
boiler
data
sets
affected
by
the
20
ppmv
correction.
We
also
considered
using
the
statistical
imputation
approach
we
used
for
nondetect
values.
See
discussion
in
Section
IV.
B
below.
The
statistical
imputation
approach
for
correcting
data
below
20
ppmv
without
dampening
variability
would
involve
imputing
a
value
between
the
reported
value
and
20
ppmv
because
the
"
true"
value
of
the
biased
data
would
lie
in
this
interval.
This
approach
would
be
problematic,
however,
given
that
many
of
the
reported
values
were
much
lower
than
20
ppmv;
our
statistical
imputation
approach
would
tend
to
overestimate
the
run
to
run
variability.
Consequently,
we
conclude
that
a
regression
analysis
approach
is
more
appropriate.
A
regression
analysis
is
particularly
pertinent
in
this
situation
because:
(
1)
we
consider
data
above
20
ppmv
used
to
develop
the
regression
to
be
unbiased;
and
(
2)
all
the
corrected
data
averages
for
which
we
are
imputing
a
standard
deviation
from
the
regression
curve
are
at
or
near
20
ppmv.
Thus,
any
potential
concern
about
downward
extrapolation
from
the
regression
would
be
minimized.
We
note
that,
although
a
regression
analysis
is
appropriate
to
estimate
run­
to­
run
variability
for
the
corrected
total
chlorine
data,
we
could
not
use
a
linear
regression
analysis
to
address
variability
of
nondetect
values.
To
estimate
a
standard
deviation
from
a
regression
analysis,
we
would
need
to
know
the
test
condition
average
emissions.
This
would
not
be
feasible,
however,
because
some
or
all
of
the
run
measurements
for
a
test
condition
are
nondetect.
In
addition,
we
are
concerned
that
a
regression
analysis
would
not
accurately
estimate
the
standard
deviation
at
low
emission
levels
because
we
would
have
to
extrapolate
the
regression
downward
to
levels
where
we
have
few
measured
data
(
i.
e.,
data
other
than
nondetect).
Moreover,
the
statistical
imputation
approach
is
more
suitable
for
handling
nondetects
because
the
approach
calculates
the
run­
to­
run
variability
by
taking
into
account
the
percent
nondetect
for
the
emissions
for
each
run.
34
A
regression
approach
would
be
difficult
to
apply
particularly
in
the
case
of
test
conditions
containing
partial
nondetects
or
a
mix
of
detect
and
nondetect
values.
Given
these
concerns
with
using
a
regression
analysis
to
estimate
the
standard
deviation
of
test
conditions
with
runs
that
have
one
or
more
nondetect
(
or
partial
nondetect)
measurements,
we
conclude
that
the
statistical
imputation
approach
best
assures
that
the
calculated
floor
levels
account
for
run­
to­
run
emissions
variability.
Compliance
with
the
Standards.
The
final
standards
are
based
on
data
that
were
corrected
to
address
specific
issues
concerning
these
data.
See
the
above
discussion
34
For
multi­
constituent
HAP
(
e.
g.
SVM)
the
emissions
for
a
run
could
be
comprised
of
fully
detected
values
for
some
HAP
and
detection
limits
for
other
HAP
that
were
nondetect.
regarding
stack
gas
moisture,
filter
affinity
for
hydrogen
chloride,
and
alkaline
compound
reactions
with
hydrogen
chloride
in
the
sampling
train.
Sources
must
demonstrate
compliance
using
a
stack
test
method
that
also
addresses
these
issues.
Sources
with
wet
stacks
must
use
Method
26A
and
follow
those
procedures
regarding
the
use
of
a
cyclone
and
the
purging
of
the
system
whenever
condensed
moisture
may
be
present
in
the
sampling
system.
Finally,
all
sources
 
those
with
either
wet
or
dry
gas­­
should
precondition
the
sampling
train
for
one
hour
prior
to
beginning
the
test
to
satisfy
the
filter's
affinity
for
hydrogen
chloride.
The
permitting
authority
will
ensure
that
sources
precondition
the
sample
train
(
under
authority
of
§
63.1209(
g)(
2))
when
they
review
and
approve
the
performance
test
plan.

D.
Mercury
Data
for
Cement
Kilns
Comment:
Several
commenters
state
that
EPA's
data
base
of
mercury
emissions
data
(
and
associated
feed
concentrations
of
mercury
in
the
hazardous
waste)
are
unrepresentative
and
unsuitable
for
use
in
determining
MACT
standards
for
cement
kilns.
These
comments
are
supported
by
an
extensive
amount
of
data
submitted
by
the
cement
manufacturing
industry
including
three
years
of
data
documenting
day­
to­
day
levels
of
mercury
in
hazardous
waste
fuels
fired
to
all
14
hazardous
waste
burning
cement
kilns.
35
The
commenters
recommend
that
EPA
use
the
commenter­
submitted
data
as
the
basis
for
assessing
cement
kilns'
performance
for
control
of
mercury
because
it
is
the
most
complete
and
representative
data
available
to
EPA.
Response:
We
agree
that
the
commenter­
submitted
mercury
data
are
more
representative
than
those
we
used
at
proposal.
First,
these
data
represent
a
significantly
larger
and
more
comprehensive
dataset
compared
to
the
one
used
to
support
the
proposed
mercury
standard.
The
commenter­
submitted
data
document
the
day­
to­
day
levels
of
mercury
in
hazardous
waste
fired
to
all
cement
kilns
for
a
three
year
period
covering
1999
to
2001.
In
total,
approximately
20,000
measurements
of
the
concentration
of
mercury
in
hazardous
waste
are
included
in
the
dataset.
When
considered
in
whole,
these
data
describe
the
performance
(
and
variability
thereof)
of
all
cement
kilns
for
the
three
year
period
because
each
measurement
represents
the
mercury
concentration
in
the
burn
tank
used
to
fire
the
kiln
over
the
course
of
a
day's
operation
(
or
longer
period).
36
In
comparison,
the
data
used
to
support
the
proposed
floor
level
consisted
of
a
much
smaller
dataset
of
approximately
50
test
conditions
representing
a
snapshot
of
performance
somewhere
in
the
range
of
normal
operations,
with
each
test
condition
representing
a
relatively
short
period
of
time
(
e.
g.,
several
hours).
37
As
discussed
at
proposal,
we
were
concerned
regarding
the
35
See
docket
item
OAR­
2004­
0022­
0049.
36
Mercury
is
a
volatile
compound
at
the
typical
operating
temperatures
of
the
air
pollution
control
devices
used
by
cement
kilns
(
i.
e.,
baghouses
and
electrostatic
precipitators).
Most
of
the
mercury
exits
the
cement
kiln
system
as
volatile
stack
emissions,
with
a
smaller
fraction
partitioning
to
the
clinker
product
or
cement
kiln
dust.
Thus,
in
general,
there
is
a
proportional
relationship
between
the
mercury
concentration
in
the
hazardous
waste
and
stack
emissions
of
mercury
(
i.
e.,
as
the
mercury
concentration
in
hazardous
waste
increases
(
assuming
mercury
concentrations
in
other
inputs
such
as
raw
materials
and
fossil
fuels
(
coal)
and
other
factors
remain
constant),
emissions
of
mercury
will
correspondingly
increase).
37
EPA's
dataset
for
mercury
for
cement
kilns
is
not
like
the
RCRA
compliance
test
emission
data
for
other
HAPs
where
each
source
designs
the
compliance
test
such
that
the
operating
limits
it
establishes
account
for
the
variability
it
expects
to
encounter
during
its
normal
operations
(
e.
g.,
semi­
and
low
volatile
metals).
This
representativeness
of
this
smaller
dataset.
See
69
FR
at
21251.
In
addition,
the
commentersubmitted
dataset
allows
us
to
better
evaluate
the
only
mercury
control
technique
used
by
existing
hazardous
waste
burning
cement
kilns
 
controlling
the
feed
concentration
of
mercury
in
the
hazardous
waste.
The
commenters
have
demonstrated
convincingly
that
the
mercury
dataset
used
at
proposal
does
not
properly
show
the
range
of
performance
and
variability
in
performance
these
cement
kilns
actually
experience,
while
the
significantly
more
robust
dataset
submitted
by
commenters
does
illustrate
this
variability.
Thus,
we
conclude
the
larger
commenter­
submitted
dataset
is
superior
to
EPA's
smaller
testing
dataset.
We
note
that
our
MACT
floor
analysis
of
the
commenter­
submitted
dataset
to
determine
which
sources
are
the
best
performers
and
to
identify
a
mercury
standard
for
cement
kilns
is
discussed
in
the
background
document.
38
Additional
discussion
of
issues
related
to
the
mercury
standard
for
cement
kilns
is
found
in
Part
Four,
Section
VI.
B
of
the
preamble.

E.
Mercury
Data
for
Lightweight
Aggregate
Kilns
Comment:
One
commenter,
an
owner
and
operator
of
seven
of
the
nine
operating
lightweight
aggregate
kilns,
states
that
the
mercury
dataset
used
by
EPA
at
proposal
is
a
limited
and
unrepresentative
snapshot
of
performance
of
their
seven
kilns.
To
support
their
position
that
the
snapshot
emissions
data
are
unrepresentative,
the
commenter
submitted
eight
months
of
data
documenting
levels
of
mercury
in
hazardous
waste
fuels
fired
to
their
lightweight
aggregate
kilns.
39
Response:
We
agree
with
the
commenter
that
their
mercury
data
submission
is
more
representative
than
those
used
at
proposal.
As
discussed
in
a
notice
for
public
comment
sent
directly
to
certain
commenters,
40
the
commenter­
submitted
dataset
documents
the
day­
to­
day
levels
of
mercury
in
hazardous
waste
fuels
fired
to
Solite
Corporation's
Arvonia
kilns
between
October
2003
and
June
2004.
The
dataset
consists
of
over
310
measurements
of
the
concentration
in
mercury
in
hazardous
waste.
Each
measurement
represents
the
mercury
concentration
of
the
burn
tank
used
to
fire
the
kiln
over
the
course
of
a
day's
operation
(
or
longer
period).
In
comparison,
the
data
used
to
support
the
proposed
floor
level
consisted
of
a
smaller
dataset
of
15
test
conditions.
The
nature
of
the
mercury
data
submitted
by
the
commenter
is
the
same
as
we
received
for
the
cement
kiln
category
discussed
in
the
preceding
section.
For
similar
reasons,
we
accept
the
more
comprehensive
commenter­
submitted
dataset
as
one
that
better
shows
the
range
of
performance
and
variability
in
performance
for
these
lightweight
aggregate
kilns.
One
notable
difference,
however,
is
that
the
commenter
submitted
mercury
data
only
for
its
company
(
representing
seven
of
nine
lightweight
aggregate
kilns).
Thus,
we
received
no
data
documenting
day­
to­
day
levels
of
the
concentration
of
mercury
in
hazardous
waste
fuels
for
the
other
two
lightweight
aggregate
kilns
owned
by
a
different
company.
For
these
two
lightweight
aggregate
kilns,
we
continue
to
use
available
data
available
in
our
database.
41
is
not
necessarily
true
for
mercury
for
cement
kilns
as
shown
in
our
analysis
of
our
mercury
dataset
at
proposal.
See
69
FR
at
21251.
38
USEPA,
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
Sections
7.5.3
and
11.0,
September
2005.
39
See
docket
items
OAR­
2004­
0022­
0270
and
OAR­
2004­
0022­
0333.
40
See
docket
item
OAR­
2004­
0022­
0370.
41
Unlike
that
is
available
for
the
commenter's
kilns,
we
note
that
we
have
compliance
test
emissions
data,
which
is
designed
to
maximize
operating
parameters
(
e.
g.,
HAP
feedrates)
that
affect
emissions,
for
the
Comment:
One
commenter
opposes
the
use
of
the
commenter­
submitted
mercury
data
because
EPA
would
be
uncritically
accepting
a
limited
and
select
data
set
from
a
commenter
with
a
direct
interest
in
the
outcome
of
its
use.
Instead,
the
commenter
suggests
EPA
use
its
section
114
authority
to
obtain
all
data
that
are
available,
not
just
the
data
selected
by
that
commenter.
Response:
We
disagree
that
we
uncritically
accepted
the
commenter­
submitted
mercury
data.
The
reason
the
commenter
submitted
data
collected
between
October
2003
and
June
2004
is
that
the
facility
was,
prior
to
October
2003,
in
the
process
of
upgrading
its
on­
site
analysis
equipment.
One
outcome
of
this
laboratory
upgrade
was
its
capability
to
detect
mercury
in
hazardous
waste
at
lower
concentrations.
Prior
to
the
upgrade,
the
facility's
on­
site
laboratory
was
capable
of
detecting
mercury
in
the
hazardous
waste
at
a
concentration
of
approximately
2
ppmw,
which
is
a
level
such
that
the
vast
majority
of
measurements
would
neither
be
detected
nor
useful
for
identifying
best
performers
and
their
level
of
performance.
42
The
June
4,
2004
cutoff
date
represents
a
practicable
date
that
measurements
could
still
be
incorporated
into
the
commenter's
public
comments
to
the
proposed
rule,
which
were
submitted
on
July
6,
2004.
Finally,
the
commenter
provided
all
waste
fuel
measurements
during
this
period
and
states
reliably
that
no
measurements
made
during
this
period
were
selectively
excluded.
43
We
also
reject
the
commenter's
suggestion
that
we
use
our
authority
under
section
114
of
the
Clean
Air
Act
to
obtain
additional
hazardous
waste
mercury
concentration
data
from
the
facility.
There
is
no
obligation
for
us
to
gather
more
performance
data,
given
that
the
statute
indicates
that
we
are
to
base
floor
levels
on
performance
of
sources
"
for
which
the
Administrator
has
emissions
information."
Section
112(
d)(
3)(
A);
CKRC,
255
F.
3d
at
867.
In
addition,
given
our
concerns
about
the
usefulness
of
measurements
with
high
detection
limits
discussed
above,
the
collection
of
additional
data
prior
to
the
laboratory
upgrade
would
not
be
productive.
When
balanced
against
the
expenditure
of
significant
resources,
both
in
time
and
level
of
effort,
to
collect
several
more
months
of
data,
we
conclude
that
obtaining
additional
mercury
measurements
is
unnecessary
because
the
available
eight
months
of
data
 
including
over
310
individual
measurements
 
represent
a
significant
amount
of
data
that
we
judge
to
be
adequately
reflective
of
the
source's
performance
and
variability
in
performance.

F.
Incinerator
Database
Comment:
Commenters
state
that
many
of
the
top
performers
(
e.
g.,
3011,
3015,
3022,
349)
dilute
emission
concentrations
in
the
stack
by
burning
natural
gas
to
initiate
reactive
waste
(
e.
g.,
explosives,
inorganic
hydrides)
or
to
decontaminate
inert
material.
Commenters
do
not
believe
these
units
should
be
considered
"
representative"
of
the
overall
incinerator
source
category
and
should
not
be
used
to
establish
standards
for
incinerators
combusting
primarily
organic
wastes.

other
two
kilns.
For
additional
discussion
on
how
these
data
were
analyzed
in
conjunction
with
the
commentersubmitted
data,
see
the
document
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
Section
7.5.3
and
12.0,
September
2005.
42
A
mercury
concentration
of
2
ppmw
in
the
hazardous
waste
corresponds
to
a
stack
concentration
of
approximately
200
ug/
dscm,
which
is
well
above
the
interim
standard
of
120
ug/
dscm
for
mercury.
43
See
also
docket
items
OAR­
2004­
0022­
0233
and
OAR­
2004­
0022­
0367.
Response:
Source
3022
has
closed
and
has
been
removed
from
the
database.
Emission
data
from
source
#
3015
(
ICI
explosives)
has
been
excluded
for
purposes
of
calculating
the
particulate
matter
floor
because
the
test
report
indicates
this
source
was
primarily
feeding
scrap
metal,
which
we
conclude
to
be
an
atypical
waste
stream
from
a
particulate
matter
compliance
perspective.
44
The
sources
identified
by
the
commenter
are
among
the
best
performing
sources
in
two
instances.
Source
3011
is
the
second
ranked
best
performer
for
the
particulate
matter
standard.
This
source
is
among
the
best
performers
for
particulate
matter
because
it
uses
a
state­
of­
the
art
baghouse
that
is
equipped
with
Teflon
coated
bags.
There
is
no
evidence
to
suggest
that
this
source
was
diluting
its
particulate
matter
emissions.
We
acknowledge
that
we
do
not
have
ash
feed
data
for
the
test
conditions
that
were
used
in
the
particulate
matter
standard
analysis.
However,
this
source
had
the
third
and
fourth
highest
metal
feed
control
levels
among
all
the
sources
used
in
the
MACT
analysis
for
the
semivolatile
and
low
volatile
metal
standards.
45
We
therefore
conclude
that
it
is
appropriate
to
include
this
source
in
the
MACT
analysis
that
determines
the
relevant
best
performers
for
particulate
matter.
Source
349
is
the
eighth
ranked
(
out
of
11)
best
performer
for
the
particulate
matter
standard.
We
acknowledge
that
the
ash
feed
level
for
this
source
is
lower
than
most
incinerators
equipped
with
baghouses.
However,
particulate
matter
emissions
from
sources
equipped
with
baghouses
are
not
significantly
affected
by
the
ash
inlet
loading
to
the
baghouse.
46
This
is
further
supported
by
the
fact
that
this
source
is
ranked
eighth
among
the
best
performers.
We
conclude
source
349
is
a
best
performer
not
because
of
its
relatively
low
ash
feed
level,
but
rather
because
it
is
equipped
with
a
well
designed
and
operated
baghouse.
It
is
therefore
appropriate
to
include
this
source
in
the
MACT
analysis.
Comment:
Commenters
state
that
source
341
should
not
be
considered
in
the
MACT
analysis
because
it
is
a
small
laboratory
waste
burner
that
processes
only
900
lbs/
hr
of
waste.
Commenters
claim
that
more
than
80
percent
of
the
waste
profile
is
nonhazardous
waste.
Response:
We
approached
this
comment
by
asking
if
it
would
be
appropriate
to
create
a
separate
subcategory
for
source
341.
We
conclude
it
is
not
necessary
to
subcategorize
hazardous
waste
incinerators
based
on
the
size
of
combustion
units.
This
is
because
the
ranking
factors
used
to
identify
the
relevant
best
performing
sources
are
normalized
in
order
to
remove
the
influence
that
combustion
unit
size
would
otherwise
have
when
identifying
best
performing
sources.
See
part
4
section
III.
D
below.
Air
pollution
control
system
types
(
a
ranking
factor
for
particulate
matter)
are
generally
sized
to
match
the
corresponding
volumetric
gas
flow
rate
in
order
to
achieve
a
given
control
efficiency.
The
size
of
the
combustor
therefore
does
not
influence
a
source's
ability
to
achieve
a
given
control
efficiency.
System
removal
efficiency
and
hazardous
waste
feed
control
MTECs
44
We
did
not
have
ash
feed
data
for
source
3015.
We
acknowledge
that
ash
feed
control
levels
do
not
significantly
affect
particulate
matter
emissions
from
sources
equipped
with
baghouses.
However,
in
this
instance,
the
particulate
matter
emissions
from
this
source
may
not
be
representative
because
this
source
may
not
have
been
feeding
any
appreciable
levels
of
ash
given
that
scrap
metal
feeds
generally
would
not
contribute
to
the
ash
loading
into
the
baghouse.
45
We
note
that
feed
control
levels
are
normalized
based
on
each
source's
gas
flowrate.
The
feed
control
levels
used
to
assess
performance
are
therefore
appropriate
indicators
that
directly
address
whether
emissions
of
these
pollutants
are
in
fact
being
diluted
by
the
combustion
of
natural
gas.
46
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Vol
I:
Description
of
Source
Categories,"
September
2005,
Section
3.2.2,
for
further
discussion.
(
ranking
factors
used
by
the
SRE/
Feed
methodology
as
described
in
part
4
section
III.
B
below)
are
also
not
influenced
by
the
size
of
the
combustor.
47
Emission
limitations
are
similarly
normalized
to
remove
the
influence
of
combustion
unit
size
by
expressing
the
standards
as
emission
concentration
limits
rather
than
as
mass
emission
rate
limits.
See
section
III.
D.
This
is
illustrated
in
the
following
example.
Assume
there
are
two
cement
kilns
side
by
side
with
similar
designs,
the
only
difference
being
one
is
twice
the
size
of
the
other,
producing
twice
as
much
clinker.
They
both
have
identical
types
of
air
pollution
control
systems
(
the
larger
source
is
equipped
with
a
larger
control
device
that
is
appropriately
sized
to
accommodate
the
larger
volumetric
gas
flow
rates
and
achieves
the
same
control
efficiency
as
the
smaller
control
device).
If
we
were
to
assess
performance
based
on
HAP
mass
emission
rates
(
e.
g.,
pounds
per
hour),
the
smaller
source
would
be
the
better
performer
because
its
mass
emission
rates
would
be
half
of
the
mass
emission
rate
of
the
larger
source,
even
though
they
both
are
achieving
the
same
back­
end
control
efficiency.
Emission
concentrations,
on
the
other
hand,
are
calculated
by
dividing
the
HAP
mass
emission
rate
(
e.
g.,
pounds
per
hour)
by
the
volumetric
gas
flowrate
(
e.
g.,
cubic
feet
per
hour).
In
the
above
example,
both
sources
would
have
identical
HAP
emission
concentrations
(
the
larger
source
has
twice
the
mass
emission
rate,
but
twice
the
volumetric
gas
flow
rate),
accurately
reflecting
their
identical
control
efficiency.
Emission
concentrations
normalize
the
size
of
each
source
by
accounting
for
volumetric
gas
flowate,
which
is
directly
tied
to
the
amount
of
raw
material
each
source
processes
(
and
subsequently
the
amount
of
product
that
is
produced).
This
is
a
reason
we
point
out
that
normalization
eliminates
the
need
to
create
subcategories
based
on
unit
size.
See
part
four
section
III.
D.
Further,
it
would
be
difficult
to
determine
an
appropriate
minimum
size
cutoff
in
which
to
base
such
a
subcategorization
determination.
Such
a
subcategorization
scheme
could
also
yield
nonsensical
floor
results,
as
was
the
case
when
we
assessed
subcategorizing
commercial
incinerators
and
on­
site
incinerators.
48
We
have
identified
source
341
as
the
best
performing
source
for
particulate
matter
and
low
volatile
metals.
It
is
the
single
best
performing
source
for
these
standards
because
it
is
equipped
with
a
state­
of­
the­
art
baghouse.
49
This
source,
which
simultaneously
feeds
hazardous
and
nonhazardous
wastes,
conducted
several
emission
tests
that
reflected
different
modes
of
operation.
The
amount
of
nonhazardous
waste
that
was
processed
in
the
combustion
unit
varied
across
test
conditions.
We
could
not
ascertain
the
exact
amount
of
hazardous
waste
processed
in
the
test
condition
that
was
used
in
the
MACT
analysis
for
low
volatile
metals
because
the
test
report
stated
the
wastes
that
were
processed
were
a
mixture
of
hazardous
and
nonhazardous
wastes,
although
we
estimate
that
at
least
26%
of
the
waste
processed
was
nonhazardous.
50
We
47
System
removal
efficiency
is
a
measure
of
the
amount
of
the
pollutant
that
is
removed
from
the
flue
combustion
gas
prior
to
being
emitted
and
likewise
is
not
influenced
by
the
size
of
the
combustor
because
backend
control
systems
are
sized
to
achieve
a
given
performance
level.
Hazardous
waste
feed
control
levels
are
normalized
to
remove
the
influence
of
combustor
size
by
dividing
each
source's
mass
feed
rate
by
its
volumetric
gas
flowrate.
48
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards",
September
2005,
Section
4.3.2
for
further
discussion.
49
See
USEPA,
"
Final
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
I:
Description
of
Source
Categories",
September
2005,
Section
3.2.1,
for
further
discussion.
50
See
USEPA,
"
Final
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
I:
Description
of
Source
Categories",
September
2005,
Section
2.1
for
further
discussion.
note
that
we
are
aware
of
several
other
incinerators
that
processed
nonhazardous
waste
at
levels
greater
than
26
percent
during
their
emission
tests.
We
therefore
do
not
believe
this
to
be
atypical
operation
that
warrants
subcategoriztion.
Moreover,
the
fact
that
this
source
was
feeding
nonhazardous
wastes
does
not
result
in
atypically
low
hazardous
waste
low
volatile
metal
feed
control
levels,
as
evidenced
by
the
relative
feed
control
ranking
for
this
source
of
thirteenth
among
the
26
sources
assessed
in
the
MACT
analysis.
It
also
has
the
highest
normalized
hazardous
waste
feed
control
level
among
the
best
performing
sources,
and
has
the
fifth
best
low
volatile
metal
system
removal
efficiency
among
those
same
26
sources.
We
repeat
that
this
source
is
being
identified
as
the
best
performing
source
primarily
because
it
is
equipped
with
a
highly
efficient
baghouse,
not
because
it
is
feeding
low
levels
of
HAP
metals
attributable
to
its
hazardous
waste.
Furthermore,
this
source
is
not
the
lowest
emitting
source
in
the
database.
There
are
two
sources
with
similar,
but
slightly
lower
low
volatile
metal
compliance
test
emissions
(
one
commercial
incinerator
and
one
onsite,
non­
commercial
incinerator).
This
provides
further
evidence
that
the
emissions
from
this
source
appropriately
represent
emissions
of
a
relevant
best
performing
source.
Regarding
the
particulate
matter
standard,
source
341
does
not
have
atypically
low
ash
feed
rates
as
compared
to
other
sources
equipped
with
baghouses.
Out
of
the
nine
best
performing
particulate
matter
sources
for
which
we
have
ash
feed
information,
this
source
ranks
fourth
(
a
ranking
of
one
is
indicative
of
the
lowest
ash
feed
rate).
Nonetheless,
as
previously
discussed,
particulate
matter
emissions
from
sources
equipped
with
baghouses
are
not
significantly
affected
by
the
ash
inlet
loading
to
the
baghouse.
We
note
that
particulate
matter
emissions
from
the
second
and
third
best
performing
source
are
not
significantly
different
from
this
source,
providing
further
evidence
that
this
source
is
representative
of
the
range
of
emissions
exhibited
by
other
well
designed
and
operating
incinerators
equipped
with
baghouses.
51
Comment:
Commenters
state
that
sources
3018
and
3019
are
identified
as
best
performers
for
mercury
emissions
for
incinerators.
After
evaluating
the
trial
burn
plans
for
these
sources,
the
commenter
believes
the
data
should
not
be
used
to
calculate
the
MACT
floor
because
the
spiking
rate
for
mercury
was
extremely
low
for
a
compliance
test.
The
ranking
for
feedrate
is
therefore
unrepresentative.
The
commenter
suggests
that
these
test
results
should
be
characterized
as
`
normal'.
Response:
We
have
verified
that
the
emission
tests
performed
for
sources
3018
and
3019
reflect
the
upper
range
of
mercury
emissions
that
are
not
to
be
exceeded
by
these
sources,
and
that
their
spiked
mercury
feed
rates
were
back­
calculated
from
a
risk
assessment.
We
therefore
conclude
that
we
properly
characterized
these
emissions
as
compliance
test
emissions
data
because
they
reflect
the
emissions
resulting
from
the
upper
bound
of
hazardous
waste
mercury
feedrates
from
these
sources.
52
Consequently,
these
data
are
properly
included
with
the
other
data
used
to
calculate
floor
standards
for
mercury
for
incinerators.

51
Source
341
particulate
matter
emissions,
after
accounting
for
variability,
equated
to
0.0015
gr/
dscf.
The
second
and
third
ranked
particulate
matter
sources
emissions,
considering
variability,
equated
to
0.0018
and
0.0023
gr/
dscf,
respectively.
52
See
February
11,
2005
memo
to
docket
titled
"
October
20
Conference
Call
with
Squibb
Manufacturing
regarding
Source
#
3018
and
3019".
Comment:
Commenters
state
the
trial
burn
plan
for
sources
3018
and
3019
describes
these
units
to
be
of
similar
design.
Thus
the
difference
in
results
between
these
two
similar
sources
is
indicative
of
additional
variability
above
and
beyond
the
run­
to­
run
variability
and
should
be
assessed
if
the
data
are
deemed
usable
at
all.
Response:
We
conclude
both
of
these
sources
are
in
fact
unique
sources
that
should
be
assessed
as
individual
sources
for
purposes
of
the
MACT
analysis.
Although
these
sources
are
of
similar
design,
we
do
not
believe
they
are
identical,
in
part
because:
1)
the
facility
itself
conducted
separate
emission
tests
for
the
two
units
(
rather
than
trying
to
avail
itself
of
the
'
data
in
lieu'
option,
which
could
save
it
the
expense
of
a
second
compliance
test,
the
obvious
inference
being
that
the
source
or
regulatory
official
regards
the
two
units
as
different);
and
2)
discussions
with
facility
representatives
indicated
these
units
are
similar,
but
not
identical.
53
As
a
result,
it
would
be
inappropriate
to
assess
emissions
variability
by
combining
the
emissions
of
these
two
sources
into
one
test
condition
given
they
are
not
identical
units.
Comment:
Commenters
state
that
emissions
data
from
source
327
should
not
be
used
to
calculate
dioxin/
furan
and
mercury
floors
because
they
claim
the
carbon
injection
system
did
not
appear
to
function
properly
during
the
test.
Response:
We
agree
with
the
commenters.
We
have
determined
that
this
source
encountered
problems
with
its
carbon
injection
system
during
the
emissions
test
from
which
the
data
were
obtained
and
subsequently
used
in
EPA's
proposed
MACT
analysis.
We
have
also
verified
that
this
source
did
not
establish
operating
parameter
limits
for
the
carbon
injection
system
as
a
result
of
this
test.
54
We
therefore
have
excluded
this
mercury
and
dioxin
data
from
the
MACT
analysis,
and
have
instead
used
emissions
data
from
an
older
test
condition
to
represent
this
source's
emissions.
Comment:
Commenters
state
that
the
emissions
data
from
source
3006
were
based
on
a
miniburn
to
determine
how
close
the
unit
was
to
achieving
the
interim
MACT
standards.
The
commenter
questions
whether
these
data
should
be
used
for
purposes
of
calculating
MACT
standards.
Response:
The
fact
that
a
source
conducts
a
voluntary
emissions
test
(
e.
g.,
a
miniburn)
to
determine
how
close
it
is
operating
to
upcoming
emission
standards
does
not
necessarily
lead
us
to
conclude
that
the
emission
data
are
inappropriate
for
purposes
of
calculating
MACT
standards.
However,
since
proposal,
we
have
determined
that
this
source
did
not
measure
cadmium
emissions
during
this
emissions
test.
As
a
result,
we
conclude
the
semivolatile
metal
emissions
data
from
this
source
should
not
be
used
in
the
MACT
standard
calculation
for
semivolatile
metals
because
the
data
do
not
represent
the
source's
combined
emissions
of
lead
and
cadmium.

II.
Affected
Sources
A.
Area
Source
Boilers
and
Hydrochloric
Acid
Production
Furnaces
Comment:
Five
commenters
state
that
the
area
sources
subject
to
the
proposed
rule
are
negligible
contributors
to
112(
c)(
6)
HAP
emissions
and
should
not
be
subject
to
major
53
Also
see
February
11,
2005
memo
to
docket
titled
"
October
20
Conference
Call
with
Squibb
Manufacturing
regarding
Source
#
3018
and
3019".
54
See
July
15,
2005
memo
to
docket
titled
"
Telephone
Conversation
with
Utah
DEQ
Regarding
2001
Clean
Harbor
Emission
Test."
source
standards
for
112(
c)(
6)
HAP.
Commenters
note
that
requiring
compliance
with
MACT
for
112(
c)(
6)
HAP
and
RCRA
for
other
toxic
pollutants
is
more
complicated
and
burdensome
for
sources
than
complying
only
with
RCRA.
Although
an
area
source
can
choose
to
become
regulated
as
a
major
source
in
order
to
reduce
some
RCRA
requirements,
they
would
become
subject
to
more
onerous
emissions
limits
under
Subpart
EEE
and
the
other
MACT
requirements.
One
of
these
commenters
states
that
subjecting
an
area
source
to
major
source
standards
under
112(
c)(
6)
sends
a
negative
message
to
industry
that
EPA
does
not
value
emissions
reduction
and/
or
chemical
substitution,
or
other
methods
used
by
area
sources
to
achieve
that
status.
EPA
is
no
longer
providing
any
incentive
for
sources
to
take
such
difficult
yet
environmentally
beneficial
steps
to
become
an
area
source.
Imposing
Title
V
permitting
requirements
on
an
entire
facility
that
operates
as
an
area
source
of
hazardous
air
pollutants
(
HAPs)
will
impose
an
unfair
and
undue
burden
on
the
facility.
Another
of
these
commenters
states
that
section
112(
c)(
6)
requires
in
pertinent
part
that
EPA
list
categories
and
subcategories
of
sources
assuring
that
sources
accounting
for
not
less
than
90%
of
the
aggregate
emissions
of
each
pollutant
(
specified
in
112(
c)(
6))
are
subject
to
standards
under
Section
112(
d)(
2)
or
(
d)(
4).
In
1998,
EPA
published
a
notice
identifying
the
list
of
source
categories
accounting
for
the
section
112(
c)(
6)
HAP
emissions
and
to
be
regulated
under
section
112(
d)
to
meet
the
90%
requirement.
(
63
FR
17838)
At
the
time,
EPA
acknowledged
that
MACT
standards
for
a
number
of
the
source
categories
had
not
yet
been
promulgated,
and
stated
that
when
the
regulations
for
each
of
those
categories
are
developed,
EPA
will
analyze
the
data
specific
to
those
sources
and
determine,
under
Section
112(
d),
in
what
manner
requirements
will
be
established.
EPA
also
stated
that:

"
Some
area
categories
may
be
negligible
contributors
to
the
90%
goal,
and
as
such
pose
unwarranted
burdens
for
subjecting
to
standards.
These
trivial
source
categories
will
be
removed
from
the
listing
as
they
are
evaluated
since
they
will
not
contribute
significantly
to
the
90%
goal."
(
63
FR
17841)

The
commenter
believes
the
"
two
or
fewer"
area
source
boilers
identified
by
EPA
in
the
present
rulemaking
are
"
negligible
contributors"
to
the
90%
goal
and
therefore,
should
not
be
required
to
adopt
the
same
MACT
emission
limitations
and
requirements
as
major
sources
of
the
112(
c)(
6)
pollutants.
The
commenter
believes
EPA's
decision
to
subject
area
source
boilers
and
hydrochloric
acid
production
furnaces
is
incorrect,
unsupported
by
the
administrative
record,
and
therefore
arbitrary
and
capricious.
One
commenter
states
that,
if
EPA
regulates
area
sources,
it
should
significantly
reduce
the
administrative
burden
for
area
sources
by:
exempting
them
from
Title
V
provisions
for
Subpart
EEE
requirements;
exempting
them
from
compliance
with
the
General
Provisions
of
63
Subpart
A;
limiting
them
to
a
one­
time
comprehensive
performance
test;
or
limiting
other
applicable
requirements.
Response:
We
continue
to
believe
that
boiler
and
hydrochloric
acid
furnace
area
sources
warrant
regulation
under
the
major
source
MACT
standards
for
mercury,
dioxin/
furan,
carbon
monoxide/
hydrocarbons,
and
destruction
and
removal
efficiency
pursuant
to
section
112(
c)(
6).
As
discussed
at
proposal
(
69
FR
at
21212),
section
112(
c)(
6)
of
the
CAA
requires
EPA
to
list
and
promulgate
section
112(
d)(
2)
or
(
d)(
4)
standards
(
i.
e.,
standards
reflecting
MACT)
for
categories
and
subcategories
of
sources
emitting
seven
specific
pollutants.
Five
of
those
listed
pollutants
are
emitted
by
boilers
and
hydrochloric
acid
production
furnaces:
mercury,
2,3,7,8­
tetrachlorodibenzofuran,
2,3,7,8­
tetrachlorodibenzo­
p­
dioxin,
polycyclic
organic
matter,
and
polychlorinated
biphenyls.
As
discussed
below,
EPA
must
assure
that
source
categories
accounting
for
not
less
than
90
percent
of
the
aggregated
emissions
of
each
enumerated
pollutant
are
subject
to
MACT
standards
(
and
of
course
is
not
prohibited
from
requiring
more
than
90
percent
of
aggregated
emissions
to
be
controlled
by
MACT
standards).
Congress
singled
out
the
pollutants
in
section
112(
c)(
6)
as
being
of
``
specific
concern''
not
just
because
of
their
toxicity
but
because
of
their
propensity
to
cause
substantial
harm
to
human
health
and
the
environment
via
indirect
exposure
pathways
(
i.
e.,
from
the
air
through
other
media,
such
as
water,
soil,
food
uptake,
etc.).
Furthermore,
these
pollutants
have
exhibited
special
potential
to
bioaccumulate,
causing
pervasive
environmental
harm
in
biota
and,
ultimately,
human
health
risks.
Section
112(
c)(
6)
of
the
CAA
requires
EPA
to
list
categories
and
subcategories
of
sources
of
seven
specified
pollutants
to
assure
that
sources
accounting
for
not
less
than
90
percent
of
the
aggregate
emissions
of
each
such
pollutant
are
subject
to
standards
under
CAA
section
112(
d)(
2)
or
112(
d)(
4).
In
1998,
EPA
issued
the
list
of
source
categories
pursuant
to
section
112(
c)(
6),
and
that
list
is
published
at
63
Fed.
Reg.
17838,
17849,
Table
2
(
April
10,
1998).
In
the
1998
listing,
EPA
identified
the
following
three
subcategories
of
the
HWC
source
category
that
emit
one
or
more
of
the
seven
section
112(
c)(
6)
pollutants:
(
1)
hazardous
waste
incinerators­­
(
emit
mercury,
dioxin,
furans,
polycyclic
organic
matter
(
POM)
and
polychlorinated
biphenyls
(
PCBs));
(
2)
Portland
cement
manufacture:
hazardous
waste
kilns
 
(
emit
mercury,
dioxin,
furans,
and
POM);
and
(
3)
lightweight
aggregate
kilns:
hazardous
waste
kilns
 
(
emit
dioxin,
furans,
and
mercury).
These
three
subcategories
are
all
subject
to
today's
rule,
which
is
issued
pursuant
to
CAA
section
112(
d)(
2).
As
explained
below,
the
HWC
NESHAP
effectively
controls
emissions
of
the
identified
section
112(
c)(
6)
pollutants
from
the
identified
subcategories.
Accordingly,
EPA
considers
the
sources
in
these
three
subcategories
as
being
"
subject
to
standards"
for
purposes
of
section
112(
c)(
6).
Specifically,
with
regard
to
hazardous
waste­
burning
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns,
EPA
is
adopting
in
this
final
rule
MACT
standards
for
mercury
and
dioxins/
furans.
EPA
has
already
adopted
MACT
standards
for
control
of
POM
and
PCBs
emitted
by
these
sources
in
the
1999
rule,
which
standards
were
not
reopened
or
reconsidered
in
this
rulemaking.
These
standards
are
the
CO/
HC
standards,
which
in
combination
with
the
Destruction
Removal
Efficiency
(
DRE)
requirement,
assure
that
these
sources
operate
continuously
under
good
combustion
conditions
which
inhibit
formation
of
POM
and
PCBs
as
combustion
by­
products,
or
destroy
these
HAP
if
they
are
present
in
the
wastes
being
combusted.
55
See
discussion
in
Part
Four,
Sections
V.
A
and
V.
B
of
this
preamble.
The
HWC
NESHAP
also
applies
to
hazardous
waste­
burning
boilers
and
hydrochloric
acid
production
furnaces.
In
particular,
for
these
boilers
and
furnaces,
this
rule
55
Courts
have
repeatedly
upheld
EPA's
authority
under
CAA
section
112(
d)
to
use
a
surrogate
to
regulate
hazardous
pollutants
if
it
is
reasonable
to
do
so.
See,
e.
g.,
National
Lime,
233
F.
3d
at
637
(
holding
that
EPA
properly
used
particulate
matter
as
a
surrogate
for
HAP
metals).
addresses
emissions
of
dioxin/
furan,
mercury,
POM
and
PCBs
either
through
specific
numeric
standards
for
the
identified
HAP,
or
through
standards
for
surrogate
pollutants
which
control
emissions
of
the
identified
HAP.
We
estimate
that
approximately
620
pounds
of
mercury
are
emitted
annually
in
aggregate
from
hazardous
waste
burning
boilers
in
the
United
States.
56
Also,
we
estimate
that
hazardous
waste
burning
boilers
and
hydrochloric
acid
production
furnaces
emit
in
aggregate
approximately
2.3
and
0.2
grams
TEQ
per
year
of
dioxin/
furan,
respectively.
Controlling
emissions
of
these
HAP
from
area
sources
consequently
reduces
emissions
of
these
HAP
through
application
of
MACT
standards.
We
note
that
only
major
source
boilers
and
hydrochloric
acid
furnaces
are
subject
to
the
full
suite
of
subpart
EEE
emission
standards.
57
Section
112(
c)(
3)
of
the
CAA
requires
us
to
subject
area
sources
to
the
full
suite
of
standards
applicable
to
major
sources
if
we
find
``
a
threat
of
adverse
effects
to
human
health
or
the
environment''
that
warrants
such
action.
We
cannot
make
this
finding
for
area
source
boilers
and
halogen
acid
production
furnaces.
69
FR
at
21212
Consequently,
as
proposed,
area
sources
in
these
categories
would
be
subject
only
to
the
MACT
standards
for
mercury,
dioxin/
furan,
and
polycyclic
organic
matter
and
polychlorinated
biphenyls
(
through
the
surrogate
standards
for
carbon
monoxide/
hydrocarbons
and
destruction
and
removal
efficiency)
to
control
the
HAP
enumerated
in
section
112(
c)(
6).
RCRA
standards
under
Part
266,
Subpart
H
for
particulate
matter,
metals
other
than
mercury,
and
hydrogen
chloride
and
chlorine
gas
would
continue
to
apply
to
these
area
sources
unless
an
area
source
elects
to
comply
with
the
major
source
standards
in
lieu
of
the
RCRA
standards.
See
§
266.100(
b)(
3)
and
the
revisions
to
§
§
270.22
and
270.66.
Commenters
refer
to
the
"
two
or
fewer"
potential
area
source
boilers
we
identified
at
proposal
as
"
negligible
contributors"
and,
therefore,
conclude
that
these
area
sources
should
not
subject
to
major
source
standards
for
emission
of
these
HAPs.
Commenters
did
not
quantify
the
amount
of
emissions
from
area
sources,
and
did
not
even
identify
how
many
area
sources
are
at
issue.
We
do
not
know
how
many
boilers
and
hydrochloric
acid
furnaces
are
area
sources.
We
apparently
underestimated
the
number
given
that
four
companies
commented
on
the
proposed
rule
saying
that
area
sources
should
not
be
subject
to
major
source
standards
for
mercury,
dioxin/
furan,
PCBs,
and
polycyclic
organic
matter,
and
one
of
those
companies
indicates
it
operates
multiple
area
sources.
Consequently,
we
continue
to
believe
that
area
sources
in
these
categories
may
have
the
potential
to
emit
more
than
negligible
levels
of
these
HAP.
We
also
note
that
the
major
source
standards
are
tailored
to
minimize
the
compliance
burden
for
sources
that
emit
low
levels
of
HAP.
Commenters
raise
concerns
about
applying
the
major
source
standards
for
HAP
enumerated
in
section
112(
c)(
6)
to
liquid
fuel
boiler
area
56
See
USEPA
``
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
V:
Emission
Estimates
and
Engineering
Costs,''
September,
2005,
Section
3.

57
We
note
that
as
a
practical
matter,
however,
the
same
MACT
standards
apply
to
both
major
and
area
source
HCl
production
furnaces.
This
is
because
major
sources
are
subject
to
the
following
standards:
CO/
HC,
DRE,
and
total
chlorine.
Because
the
CO/
HC
and
DRE
standards
are
surrogates
to
control
dioxin/
furan,
and
the
total
chlorine
standard
is
a
surrogate
to
control
metal
HAP,
area
sources
are
subject
to
the
same
standards
that
address
dioxin/
furan,
polycyclic
organic
matter,
polychlorinated
biphenyls,
and
mercury.
There
is
an
enforcement
difference
between
the
requirements,
however.
For
area
sources,
an
exceedance
of
the
total
chlorine
standard
(
or
failure
to
ensure
that
compliance
is
maintained)
relates
to
control
of
mercury
only
while
for
a
major
source,
the
same
failure
relates
to
control
of
mercury,
other
metal
HAP,
and
HCl
and
chlorine.
sources.
The
emission
standard
compliance
burden
for
liquid
fuel
boilers
that
have
the
potential
to
emit
only
low
levels
of
mercury,
dioxin/
furan,
and
polycyclic
organic
matter
is
minimal.
For
example,
sources
that
emit
low
levels
of
mercury
because
their
feedstreams
have
low
levels
of
mercury
can
elect
to
comply
with
the
mercury
emission
standard
by
documenting
that
the
mercury
in
feedstreams
will
not
exceed
the
standard
assuming
zero
removal
by
emission
control
equipment.
We
note
that
75%
of
the
liquid
fuel
boilers
in
our
data
base,
and
the
two
boilers
cited
by
commenters,
do
not
have
emission
control
devices.
The
compliance
burden
for
the
major
source
standards
for
dioxin/
furan
and
for
the
surrogates
to
control
other
polycyclic
organic
matter
 
carbon
monoxide/
hydrocarbons
and
destruction
and
removal
efficiency
(
DRE)­­
should
also
be
minimal
for
area
source
liquid
fuel
boilers.
The
dioxin/
furan
standard
applicable
to
the
90%
of
liquid
fuel
boilers
with
wet
or
no
air
pollution
control
equipment
is
compliance
with
the
carbon
monoxide/
hydrocarbon
standard
and
the
DRE
standard.
Liquid
fuel
boilers
already
comply
with
these
same
standards
under
RCRA.
The
surrogate
standards
to
control
other
polycyclic
organic
matter
are
also
the
carbon
monoxide/
hydrocarbon
and
DRE
standards.
Finally,
we
note
that
the
DRE
requirement
under
Subpart
EEE
is
less
burdensome
than
the
DRE
requirement
under
RCRA.
Under
Subpart
EEE,
a
source
needs
to
conduct
a
one­
time
only
DRE
test,
provided
that
design
and
operation
does
not
change
in
a
manner
than
could
adversely
affect
DRE.
Under
RCRA,
the
DRE
test
must
be
conducted
each
time
the
RCRA
permit
is
renewed.
The
incremental
compliance
burden
associated
with
the
other
Subpart
EEE
major
source
requirements,
such
as
the
operations
and
maintenance
plan,
the
startup,
shutdown,
and
malfunction
plan,
operator
training,
and
the
automatic
waste
feed
cutoff
system
should
also
be
minimal
for
liquid
fuel
boilers
without
an
emission
control
device.
In
addition,
most
of
the
requirements
are
either
identical
to
or
very
similar
to
requirements
under
RCRA
with
which
these
area
sources
are
already
complying.
58
B.
Boilers
Eligible
for
the
RCRA
Low
Risk
Waste
Exemption
Comment:
Several
commenters
state
that
EPA
should
exempt
those
boilers
that
qualify
as
Low
Risk
Waste
Exemption
(
LRWE)
burners
under
the
RCRA
Boiler
and
Industrial
Furnace
Rule
at
§
266.109
from
the
MACT
particulate
matter
and
destruction
and
removal
efficiency
(
DRE)
standards
because
EPA
has
not:
(
1)
made
a
demonstration
that
the
data
used
to
provide
the
exemption
to
low
risk
burners
under
RCRA
is
no
longer
valid;
or
(
2)
established
in
the
affirmative
that
regulating
these
units
will
provide
any
benefit
to
human,
health
and
the
environment.
Commenters
believe
that
regulating
LRWE
units
under
Subpart
EEE
is
unnecessary
and
inconsistent
with
RCRA
subtitle
C
and
more
importantly,
appears
to
be
controlling
LRWE
units
for
control's
sake.
Commenters
also
state
that
EPA
has
not
properly
addressed
the
requirements
of
CAA
section
112(
n)(
7)
regarding
the
inconsistency
between
the
requirements
for
Low
Risk
Waste
Exempt
(
LRWE)
units
under
RCRA
and
those
of
Subpart
EEE.
The
purported
purpose
of
58
RCRA,
40
CFR
Part
264
requirements
that
are
similar
to
MACT
requirements
include:
the
general
inspection
requirements
and
personnel
training
requirements
of
Subpart
B;
the
preparedness
and
prevention
requirements
of
Subpart
C,
including
design
and
operation
of
facility,
testing
and
maintenance
of
equipment,
and
access
to
communications
or
alarm
system;
the
contingency
plan
and
emergency
procedures
requirements
of
Subpart
D;
and
the
operating
requirements
and
monitoring
and
inspection
requirements
of
Subpart
O.
section
112(
n)(
7)
is
to
allow
EPA
to
avoid
imposing
additional
emission
limitations
on
a
source
category
subcategory
when
such
limitations
would
be
unnecessary
and
duplicative.
In
addition,
commenters
state
that
the
costs
associated
with
this
MACT
are
much
more
than
improved
feed
control
or
better
back­
end
control.
This
proposed
rule
also
requires
substantial
dollar
investment
in
improved
data
acquisition,
computer
controls
and
recordkeeping
systems,
performance
testing,
training,
development
of
plans,
and
other
regulatory
requirements.
Response:
Boilers
and
hydrochloric
acid
production
furnaces
that
currently
qualify
for
the
RCRA
§
266.109
low
risk
waste
exemption
are
not
exempt
from
Subpart
EEE
under
the
final
rule.
The
Administrator
does
not
have
the
authority
under
CAA
section
112(
d)
to
exempt
sources
that
comply
with
RCRA
§
266.109.
Indeed,
there
is
no
necessary
connection
between
the
two
provisions,
since
one
is
technology­
based
and
the
other
is
risk­
based.
CAA
section
112(
d)(
2)
requires
the
Administrator
to
establish
technology­
based
emission
standards,
standards
that
require
the
maximum
degree
of
reduction
in
emissions
that
is
deemed
achievable.
Although
section
112(
d)(
4)
gives
the
Administrator
the
authority
to
establish
health­
based
emission
standards
in
lieu
of
the
MACT
standards
for
pollutants
for
which
a
health
threshold
has
been
established,
we
cannot
use
that
authority
to
develop
health­
based
standards
for
sources
that
comply
with
RCRA
§
266.109
because
those
sources
emit
HAP
for
which
a
health
threshold
has
not
been
established.
The
final
rule
complies
fully
with
CAA
section
112(
n)(
7)
by
coordinating
applicability
of
the
RCRA
and
CAA
requirements
and
precluding
dual
requirements.
For
example,
RCRA
requirements
that
are
duplicative
of
MACT
requirements
will
be
removed
from
the
RCRA
operating
permit
when
the
permitting
authority
issues
a
certification
of
compliance
after
the
source
submits
a
Notification
of
Compliance.
We
also
note
that
the
MACT
standards
are
tailored
to
impose
minimal
burden
on
sources
that
have
low
emissions
of
HAP.
The
particulate
matter
emission
standard
and
associated
testing
can
be
waived
(
similar
to
the
§
266.109
exemption)
for
boilers
that
elect
to
document
that
emissions
of
total
metal
HAP
do
not
exceed
the
limits
provided
by
§
63.1206(
b)(
14).
Hydrochloric
acid
production
furnaces
are
not
subject
to
a
particulate
matter
emission
standard.
The
compliance
burden
with
the
destruction
and
removal
efficiency
(
DRE)
standard
is
also
minimal
given
that
it
is
a
one­
time
test,
provided
that
the
source
does
not
change
its
design
or
operation
in
a
manner
that
would
adversely
affect
DRE.
In
addition,
the
compliance
burden
for
sources
with
low
levels
of
metals
in
their
feedstreams
is
minimal.
Sources
can
document
compliance
with
the
metals
emission
standards
by
assuming
all
metals
in
the
feed
are
emitted
(
i.
e.,
by
assuming
zero
system
removal
efficiency).
Under
this
procedure,
boilers
burning
relatively
clean
wastes
are
not
required
to
conduct
a
performance
test
to
document
compliance
with
the
metals
emission
standards.
Further,
we
note
that
the
MACT
standard
to
control
organic
HAP
emissions
other
than
dioxin/
furan
is
the
same
as
the
RCRA
standard
 
demonstrating
good
combustion
conditions
by
complying
with
a
carbon
monoxide
standard
of
100
ppmv.
Finally,
we
note
that
the
ancillary
requirements
under
MACT
(
e.
g.,
personnel
training;
operating
and
maintenance
plan;
startup,
shutdown,
and
malfunction
plan)
should
not
pose
substantially
higher
costs
than
similar
requirements
under
RCRA.
See
response
to
comment
in
Section
A
above.
To
the
extent
that
compliance
costs
increase,
we
have
accounted
for
those
costs
in
our
estimates
of
the
cost
of
the
final
rule.
59
C.
Mobile
Incinerators
Comment:
A
mobile
incinerator
used
as
a
directly­
fired
thermal
desorption
unit
at
a
Superfund
remediation
site
should
not
be
an
affected
source
under
this
rule.
Response:
EPA
is
not
determining
or
changing
the
applicability
of
any
hazardous
waste
burning
unit
under
today's
rule.
A
combustion
unit
that
treats
hazardous
waste
and
meets
the
definition
of
incinerator
at
40
CFR
260.10
is
an
affected
source
under
this
rule.
40
CFR
part
63
also
defines
a
source
as
any
building,
structure,
facility,
or
installation
which
emits
or
may
emit
any
air
pollutant.
A
mobile
incinerator
at
a
remediation
site
meets
this
definition.
Comment:
One
commenter
states
that
a
subcategory
with
different
standards
must
be
created
for
mobile
incinerators,
or
the
standards
for
incinerators
must
be
calculated
using
actual
emissions
data
from
mobile
units.
Response:
EPA
did
not
have
any
emissions
data
from
mobile
incinerators
in
the
database
for
the
proposed
rule.
That
data
base
was
developed
over
many
years
with
ample
opportunity
for
public
comment.
We
developed
a
data
base
for
incinerators
to
support
the
1996
proposed
rule
(
61
FR
17358)
and
noticed
that
data
base
for
public
comment
on
January
7,
1997
(
64
FR
52828).
We
updated
that
data
base
in
July
2002,
and
noticed
the
revised
data
base
for
public
comment
(
67
FR
44452).
We
used
that
revised
data
base
to
support
the
proposed
rule.
We
did
not
receive
comments
providing
data
for
mobile
incinerators
as
a
result
of
either
public
notice.
One
commenter
on
the
proposed
rule
provided
a
summary
of
emissions
data
from
one
test
at
a
mobile
incinerator.
The
commenter
suggested
that
the
data
support
its
view
that
its
mobile
incinerator
is
unique
and
that
EPA
should
consider
subcategorizing
incinerators
according
to
mobile
incinerators
versus
other
incinerators.
We
analyzed
these
data
and
conclude
that
the
final
standards
are
readily
achievable
by
this
source.
Moreover,
as
explained
elsewhere,
EPA's
approach
to
assess
the
need
for
subcategorization
is
to
apply
a
statistical
test
to
determine
whether
the
emissions
data
are
statistically
different
from
the
remaining
group.
Given
that
owners
and
operators
of
mobile
incinerators
have
not
provided
emissions
data
prior
to
proposal,
and
that
the
commenter
provides
summarized
data
for
only
one
mobile
incinerator
(
which
also
indicate
that
the
source
can
achieve
the
emission
standards
in
the
final
rule);
we
are
not
compelled
to
gather
additional
information,
particularly
given
our
time
constraints
to
promulgate
the
final
rule
under
a
court­
ordered
deadline.
Comment:
In
support
of
subcategorizing
mobile
incinerators,
commenters
state
that
mobile
thermal
treatment
systems
are
substantially
different
from
hazardous
waste
incinerators.
They
are
much
smaller
in
size,
firing
capacity
rate,
refractory
lining,
and
operating
temperatures.
Most
of
them
treat
contaminated
soil­
so
have
very
high
particulate
feedrate
loading
with
high
ash
content,
rapid
kiln
rotation
rate,
and
counter­
current
flow
design
like
cement
kilns.
This
results
in
high
particulate
matter
emissions.
They
operate
only
for
a
short
duration
at
a
site
(
usually
less
than
6
months),
and
have
no
flexibility
with
regard
to
their
waste
feed.

59
USEPA
``
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
V:
Emission
Estimates
and
Engineering
Costs,''
September,
2005.
Response:
We
recognize
that
there
is
variability
between
various
sources'
with
regard
to
size,
capacity,
operating
temperatures
etc.,
and
so
we
applied
a
statistical
test
to
assess
the
need
of
subcategorization,
as
has
been
discussed
above.
The
emissions
data
provided
by
the
commenter
also
indicate
the
source
can
achieve
the
final
standards.
The
soil
entrained
in
desorber
off­
gases
of
mobile
incinerators
has
a
relatively
large
particle
size,
and
is
very
easy
to
capture
with
conventional
particulate
control
systems
(
such
as
a
fabric
filter)
used
by
the
incinerators.
Comment:
Since
mobile
incinerators
are
relocated
from
site
to
site,
the
new
source
standard
should
not
apply
based
on
the
erection
date
of
the
mobile
unit.
Response:
We
are
not
changing
the
applicability
of
a
new
or
reconstructed
source
designation
in
this
rulemaking.
The
relocation
issue
is
addressed
in
the
definition
of
"
construction"
in
40
CFR
Section
63.2,
which
states:
"
Construction
does
not
include
the
removal
of
all
equipment
comprising
an
affected
source
from
an
existing
location
and
the
reinstallation
of
such
equipment
at
a
new
location
.
.
.
."
(
emphasis
added).
Therefore,
the
relocation
of
an
existing
Subpart
EEE
affected
source,
such
as
a
mobile
incinerator,
would
not
result
in
that
mobile
incinerator
becoming
a
"
new"
source.
Keep
in
mind
also
that
the
relocation
exemption
only
applies
to
affected
sources.
If
a
mobile
incinerator
is
relocated
from
an
R&
D
facility
(
where
the
unit
is
not
an
affected
source
per
Table
1
to
Section
63.1200)
to
a
location
where
the
mobile
incinerator
would
become
an
affected
source,
the
relocation
exemption
within
the
definition
of
"
construction"
would
not
apply
and
the
mobile
incinerator
would
be
a
"
new"
source.
Also,
with
regard
to
leased
sources,
the
owner/
operator
of
the
facility
is
responsible
for
all
affected
sources
operating
at
his/
her
facility
regardless
of
whether
the
sources
are
owned
or
leased.
The
owner
or
operator
should
obtain
from
the
leasing
company
all
relevant
information
pertaining
to
the
affected
source
in
order
to
be
able
to
demonstrate
that
the
affected
source
is
operating
in
compliance
with
the
appropriate
standards.

III.
Floor
Approaches
In
this
section
we
discuss
comments
addressing
methodologies
used
in
this
rule
for
determining
MACT
floors.
We
address
comments
relating
both
to
general,
overarching
issues
and
to
the
specific
methodologies
used
in
the
rule.
Our
most
important
point
is
that
the
methodologies
EPA
selected
reasonably
estimate
the
performance
of
the
best
performing
sources
by
best
accounting
for
these
sources'
total
variability.

A.
Variability
1.
Authority
to
Consider
Emissions
Variability
Comment:
Many
commenters
concur
with
our
approach
to
account
for
emissions
variability
while
several
commenters
believe
that
our
approach
does
not
adequately
account
for
emissions
variability.
See
discussions
on
separate
topics
below.
One
commenter,
however,
states
that
use
of
variability
factors
(
however
derived)
is
inherently
unlawful
and
arbitrary
and
capricious.
The
commenter
notes
that,
because
floors
for
existing
sources
must
reflect
the
"
average"
emission
level
achieved
by
the
relevant
best
performing
sources,
they
cannot
reflect
any
worse
levels
of
performance
from
the
best
performers.
Indeed,
the
argument
is
that
the
Clean
Air
Act
already
accounts
for
variability
by
requiring
EPA
to
base
existing
source
floors
on
the
average
emission
level
achieved
by
the
best
performing
sources.
The
commenter
continues
by
stating
that
EPA
has
added
variability
factors
both
to
each
individual
source's
performance
and
to
the
collective
performance
of
the
alleged
best
performers,
in
each
case
purporting
to
find
an
emission
level
that
the
individual
or
group
would
meet
ninety­
nine
times
out
of
100
future
emission
tests.
Thus,
EPA
ignores
sources'
measured
performance
in
favor
of
the
theoretical
worst
performance
that
might
ever
be
expected
from
them.
By
looking
to
the
best
performers'
worst
performance
rather
than
their
average
performance,
EPA
would
set
weaker
floors
than
the
Clean
Air
Act
allows.
In
addition,
the
commenter
notes
that
EPA's
approach
to
account
for
emissions
variability
is
arbitrary
and
capricious
because
EPA
never
explains
why
it
chose
the
99th
percentile
for
its
variability
adjustments
rather
than
some
other
percentile.
Finally,
the
commenter
notes
that
EPA
appears
to
indicate
that
its
variability
analysis
would
either
be
applied
to
variation
between
sources
or
would
affect
EPA's
statistical
analysis
of
the
variation
between
sources.
The
commenter
states
that
any
attempt
by
EPA
to
add
a
variability
factor
to
adjust
for
intersource
variability
is
unlawful
and
arbitrary
and
capricious.
Response:
Our
response
explains
our
approach
to
estimating
best
performing
sources'
variability
and
addresses
the
following
issues:
(
1)
considering
the
variability
in
each
source's
performance
is
necessary
to
identify
the
best
performing
sources
and
their
level
of
performance
(
2)
EPA
reasonably
considered
variability
in
ranking
sources
to
identify
the
best
performers
and
in
considering
the
range
of
best
performing
sources'
performance
over
time
to
identify
an
emission
level
that
the
average
of
those
sources
can
achieve;
(
3)
considering
variability
at
the
99th
percentile
level
is
reasonable;
(
4)
considering
intersource
variability
by
pooling
run­
to­
run
variability
is
appropriate;
and
(
5)
compliance
test
conditions
do
not
fully
reflect
all
of
best
performing
sources'
performance
variability.
a.
Variability
Must
Be
Considered.
Variability
in
each
source's
performance
must
be
considered
at
the
outset
in
identifying
the
best
performing
sources.
This
is
simply
another
way
of
saying
that
best
performers
are
those
that
perform
best
over
time
(
i.
e.
day­
in,
dayout
a
reasonable
approach.
This
approach
not
only
reasonably
reflects
the
statutory
language,
but
also
furthers
the
ultimate
objective
of
section
112
which
is
to
reduce
risk
from
exposure
to
HAP.
Since
most
of
the
risk
from
exposure
to
emissions
from
this
source
category
is
associated
with
chronic
exposure
to
HAP
(
see
Part
1
section
VI
above),
assessing
a
source's
performance
over
time
by
accounting
for
variability
is
reasonable
and
appropriate.
For
similar
reasons,
variability
must
be
considered
in
ascertaining
these
sources'
level
of
performance.
Floors
for
existing
sources
must
reflect
"
the
average
emission
limitation
achieved
by
the
best
performing
12
percent"
of
sources,
and
for
new
sources,
must
reflect
"
the
emission
control
that
is
achieved
in
practice
by
the
best
controlled
source."
Section
112
(
d)
(
3).
EPA
construes
these
requirements
as
meaning
achievable
over
time,
since
sources
are
required
to
achieve
the
standards
at
all
times.
This
interpretation
has
strong
support
in
the
case
law.
See
Sierra
Club
v.
EPA,
167
F.
3d
658,
665
(
D.
C.
Cir.
1999),
stating
that
"
EPA
would
be
justified
in
setting
the
floors
at
a
level
that
is
a
reasonable
estimate
of
the
performance
of
the
`
best
controlled
similar
unit'
under
the
worst
reasonably
foreseeable
circumstances.
It
is
reasonable
to
suppose
that
if
an
emissions
standard
is
as
stringent
as
`
the
emissions
control
that
is
achieved
in
practice'
by
a
particular
unit,
then
that
particular
unit
will
not
violate
the
standard.
This
only
results
if
`
achieved
in
practice'
is
interpreted
to
mean
`
achieved
under
the
worst
foreseeable
circumstances';
see
also
National
Lime
Ass'n
v.
EPA,
627
F.
2d
416,
431
n.
46
(
D.
C.
Cir.
1980)
(
where
a
statute
requires
that
a
standard
be
`
achievable,'
it
must
be
achievable
under
"
the
most
adverse
circumstances
which
can
reasonably
be
expected
to
recur");
The
court
has
further
indicated
that
EPA
is
to
account
for
variability
in
assessing
sources'
performance
for
purposes
of
establishing
floors,
and
stated
that
this
assessment
may
require
EPA
to
make
reasonable
estimates
of
performance
of
best
performing
sources.
CKRC,
255
F.
3d
at
865­
66;
Mossville
Environmental
Action
Now
v.
EPA,
370
F.
3d
1232,
1242
(
D.
C.
Cir.
2004)(
maximum
daily
variability
must
be
accounted
for
when
establishing
MACT
floors).
60
Indeed,
EPA's
error
in
CKRC
was
not
in
estimating
best
performing
sources'
variability,
but
in
using
an
unreasonable
means
of
doing
so.
CKRC,
255
F.
3d
at
866;
Mossville,
370
F.
3d
at
1241.
Since
the
emission
standards
in
today's
rule
must
be
met
at
all
times,
the
standards
need
to
account
for
performance
variability
that
could
occur
on
any
single
day
of
these
sources'
operation
(
assuming
proper
design
and
operation).
See
Mossville,
370
F.
3d
at
1242
(
upholding
MACT
floor
because
it
was
established
at
a
level
that
took
into
account
sources'
long
term
performance,
not
just
performance
on
individual
days).
Moreover,
since
EPA's
database
consists
of
single
data
points
(
because
there
are
no
continuous
emission
monitors
for
HAPs
in
stack
emissions),
EPA
must
of
necessity
estimate
long­
term
performance,
including
daily
maximum
performance,
from
this
limited
set
of
short
term
data.
b.
EPA
Reasonably
Considered
Variability
in
Ranking
Sources
to
Identify
the
Best
Performers
and
in
Considering
the
Range
of
Best
Performing
Sources'
Performance
Over
Time
to
Identify
an
Emission
Level
that
the
Average
of
Those
Sources
Can
Achieve.
(
1)
Selecting
Best
Performing
Sources.
Each
of
the
floor
methodologies
used
in
the
rule
considers
various
factors
in
ranking
which
sources
are
the
best
performing.
For
each
methodology,
we
therefore
consider
the
quantifiable
variability
of
the
ranking
factors
in
determining
which
are
the
best
performing
sources.
69
FR
at
21230­
31.
Specifically,
we
assess
run­
to­
run
variability
(
normally
the
only
type
of
variability
which
we
can
quantify)
of
the
factors
used
under
each
methodology
to
rank
best
performers.
Where
SRE/
Feed
is
the
ranking
methodology,
we
thus
assess
run­
to­
run
variability
of
hazardous
waste
HAP
feedrate
and
of
system
removal
efficiency.
Where
ranking
is
based
on
sources'
emissions
(
the
straight
emissions
methodology),
we
assess
the
run­
to­
run
variability
of
emission
levels.
Where
we
use
the
air
pollution
control
device
methodology
for
ranking,
we
assess
the
run­
torun
variability
of
emissions
of
the
lowest­
emitting
sources
(
as
we
do
for
straight
emissions)
using
the
best
air
pollution
control
devices.
For
hydrochloric
acid
production
furnaces,
we
assess
the
run­
to­
run
variability
of
total
chlorine
system
removal
efficiency.
Id.
61
To
account
for
run­
to­
run
variability
in
these
ranking
factors,
we
rank
sources
by
the
99th
percentile
upper
prediction
limit
(
UPL99).
The
UPL99
is
an
estimate
of
the
value
that
the
source
would
achieve
in
99
of
100
future
tests
if
it
could
replicate
the
operating
conditions
of
the
compliance
test.
Id.
at
21231.

60
See
also
Chemical
Manufacturers
Ass'n
v.
EPA,
870
F.
2d
177,
228
(
5th
Cir.
1989)
("
The
same
plant
using
the
same
treatment
method
to
remove
the
same
toxic
does
not
always
achieve
the
same
result.
Tests
conducted
one
day
may
show
a
different
concentration
of
the
same
toxic
than
are
shown
by
the
same
test
the
next
day.
This
variability
may
be
due
to
the
inherent
inaccuracy
of
analytical
testing,
i.
e.
`
analytical
variability,'
or
to
routine
fluctuations
in
a
plant's
treatment
performance.")
61
These
ranking
methodologies
are
discussed
later
in
this
section
of
the
preamble,
and
in
USEPA,
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
7.
(
2).
Assessing
the
Best
Performers'
Level
of
Performance
Over
Time.
Once
we
identify
the
best
performing
sources,
we
need
to
consider
their
emissions
variability
to
establish
a
floor
level
that
the
average
of
the
best
performing
sources
can
achieve
day­
in,
day­
out.
There
are
two
components
of
emissions
variability
that
must
be
considered:
run­
torun
variability
and
test­
to­
test
variability.
Run­
to­
run
emissions
variability
encompasses
variability
in
individual
runs
comprising
the
compliance
tests,
and
includes
uncertainties
in
correlation
of
monitoring
parameters
and
emissions,
and
imprecision
of
stack
test
methods
and
laboratory
analyses.
See
69
FR
at
21232.62
Test­
to­
test
emissions
variability
is
the
variability
that
exists
between
multiple
compliance
tests
conducted
at
different
times
and
includes
the
variability
in
control
device
collection
efficiency
caused
by
testing
at
different
points
in
the
maintenance
cycle
of
the
emission
control
device63,
and
the
variability
caused
by
other
uncontrollable
factors
such
as
using
a
different
stack
testing
crew
or
different
analytical
laboratory,
and
by
different
weather
conditions
(
e.
g.,
ambient
moisture
and
temperature)
that
may
affect
measurements.
We
are
able
to
quantify
run­
to­
run
variability.
We
do
so
by
applying
a
99th
percentile
modified
upper
prediction
limit
to
the
averaged
emissions
of
the
best
performing
sources.
Id.
at
21233
and
Technical
Support
Document
Volume
III
section
7.2.
The
modified
upper
prediction
limit
accounts
for
run­
to­
run
variability
of
the
best
performers
by
pooling
their
run
variance
(
i.
e.,
within­
test
condition
variability).
64
See
Chemical
Manufacturer's
Ass'n
v
EPA,
870
F.
2d
177,
228
(
5th
Cir.
1989)
(
upholding
use
of
a
variability
factor
derived,
as
here,
by
pooling
the
performance
variability
of
the
best
performing
plants).
Using
this
approach,
we
ensure
that
the
average
of
the
best
performing
sources
will
be
able
to
achieve
the
floor
in
99
of
100
future
performance
tests,
assuming
these
best
performing
sources
could
replicate
their
performance
when
attempting
to
operate
under
identical
conditions
to
those
used
for
the
compliance
test
establishing
the
source
as
best
performing.
As
just
noted,
we
call
this
value
the
modified
UPL
99.
The
only
instance
in
which
we
are
able
to
quantify
test­
to­
test
variability
(
as
noted
above,
the
other
significant
component
of
total
operating
variability)
is
for
fabric
filters
(
baghouses)
when
used
to
control
emissions
of
particulate
matter.
The
modified
UPL
99
in
these
instances
reflects
not
only
run­
to­
run
variability,
but
test­
to­
test
variability
as
well.
That
total
variability
is
expressed
by
the
Universal
Variability
Factor
which
is
derived
from
analyzing
long­
term
variability
in
particulate
matter
emissions
for
best
performing
sources
across
all
of
the
source
categories
sources
that
are
equipped
with
fabric
filters.
69
FR
at
21233.
See
also
the
discussion
below
in
Section
III.
A.
2.

62
Analytic
variability
exists,
and
normally
must
be
accounted
for
in
establishing
technology­
based
standards
based
on
performance
of
the
best­
performing
plants.
Chemical
Manufacturers
Ass'n
v.
EPA,
870
F.
2d
at
230.
63
There
are
myriad
factors
that
affect
performance
of
an
emissions
control
device.
These
factors
change
over
time,
including
during
the
maintenance
cycle
of
the
device,
such
that
it
is
virtually
impossible
to
conduct
future
compliance
tests
under
conditions
that
replicate
the
performance
of
the
control
device.
See
USEPA,
"
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
5.3.
64
We
note
that
the
Agency
used
a
statistical
approach
when
proposing
the
NESHAP
for
Electric
Utility
Steam
Generating
Units.
See
memo
from
William
Maxwell,
EPA,
to
Utility
MACT
Project
Files,
entitled,
"
Analysis
of
variability
in
determining
MACT
floor
for
coal­
fired
electric
utility
steam
generating
units,"
dated
Nov.
26,
2003,
Docket
A­
92­
55.
Test­
to­
test
variability
must
be
accounted
for
in
other
instances
as
well,
however.
It
follows
that
if
the
performance
of
most
efficient
fabric
filters
varies
over
time
relative
to
particulate
matter
emissions,
then
so
does
their
performance
relative
to
the
non­
mercury
metal
HAP
emissions.
We
also
believe
that
particulate
matter
emissions
variability
from
sources
equipped
with
back­
end
controls
other
than
fabric
filters
also
exists,
and
is
furthermore
likely
to
be
higher
than
what
was
calculated
for
fabric
filters
because
there
are
more
uncertainties
associated
with
the
correlations
between
operating
parameter
limits
and
control
efficiency
for
these
devices.
65
Again,
it
clearly
follows
that
if
the
performance
of
these
other
control
devices
varies
relative
to
particulate
matter
emissions
(
perhaps
even
more
than
what
has
already
been
quantified
for
fabric
filters),
then
so
does
their
performance
relative
to
the
non­
mercury
metal
HAP
emissions.
Although
we
cannot
quantify
this
test­
to­
test
variability,
we
can
document
its
existence
and
its
significance.
We
conducted
two
parallel
analyses
examining
all
situations
where
we
had
multiple
test
conditions
for
the
sources
ranked
as
best
performing
performing
(
examining
separate
pools
for
best
performing
sources
under
both
the
straight
emissions
and
SRE/
feed
ranking
methodologies).
These
analyses
showed
that
these
sources'
emissions
do
in
fact
vary
over
time,
sometimes
significantly.
In
many
instances
sources
had
poorer
system
removal
efficiencies
and
higher
emission
levels
than
those
in
the
compliance
test
used
to
identify
the
source
as
best
performing.
We
further
projected
that
in
many
instances
these
best
performing
sources
would
not
achieve
their
own
UPL
99,
the
statistically
determined
prediction
limit
which
captures
99
out
of
100
future
three­
run
test
averages
for
the
source,
if
they
were
to
operate
at
the
poorer
system
removal
efficiency
of
its
earlier
test
and
used
the
federate
of
its
later
(
best­
performing)
compliance
test.
This
is
significant
because
the
UPL
99
reflects
all
of
a
source's
run­
to­
run
variability.
Failure
to
meet
the
UPL
99
thus
shows
both
that
further
variability
exists,
namely
test­
to­
test
variability,
and
that
it
is
a
significant
component
of
total
variability.
We
obtained
similar
results
when
we
projected
best
performing
sources'
performance
based
on
each
of
these
sources'
overall
system
removal
efficiency
obtained
by
pooling
the
removal
efficiencies
of
all
of
its
tests.
In
many
instances,
moreover,
these
projected
levels
exceeded
floor
levels
calculated
by
using
the
straight
emissions
approach,
which
ranks
best
performers
as
those
with
the
lowest
emission
levels.
This
point
is
discussed
further
in
Section
III.
B
below.
EPA's
analysis
is
set
out
in
detail
in
chapters
16
and
17
of
Volume
III
of
the
Technical
Support
Document.
66
EPA's
conclusion
is
that
total
variability
includes
both
run­
to­
run
and
test­
to­
test
variability,
and
that
both
must
be
accounted
for
in
determining
which
are
the
best
performing
sources
and
what
are
their
levels
of
performance
over
time.
As
explained
in
the
following
65
For
example,
sources
equipped
with
electrostatic
precipitators
generally
establish
multiple
operating
limits
to
best
assure
compliance
with
the
emission
standard
(
feed
control
limits,
power
input
limits,
etc.).
There
is
not
an
exact
correlation
between
emission
levels
and
operating
levels
because
there
are
several
factors
that
can
affect
the
control
efficiency
of
these
air
pollution
control
systems,
such
as
variations
in
inlet
loads,
power
inputs,
spark
rates,
humidity,
as
well
as
particle
resistivity.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Sections
16
and
17.
66
We
explain
in
those
sections
that
these
projections
assume
that
system
removal
efficiencies
are
constant
across
differing
HAP
federates
and
that
the
sources'
historical
(
poorer)
system
removal
efficiencies
were
not
the
primary
result
of
operating
at
poorer
`
controllable'
conditions
relative
to
the
most
recent
test
condition.
These
are
reasonable
assumptions,
as
explained
in
section
17.
3
of
Volume
III
of
the
Technical
Support
Document,
although
these
assumptions
also
create
a
measure
of
uncertainty
regarding
the
emissions
projections.
Sections
B
and
C,
EPA
has
accordingly
adopted
floor
methodologies
which
account
for
this
total
variability
either
quantitatively
or
qualitatively.
The
approach
advocated
by
the
commenter
simply
ignores
that
variability
exists.
Since
this
approach
is
contrary
to
both
fact
and
law,
EPA
is
not
adopting
it.
c.
Quantifying
Run­
to­
Run
Variability
at
the
99th
Percentile
Level
Is
Reasonable.
We
selected
the
99%
prediction
limit
to
ensure
a
reasonable
level
 
namely
the
99th
percentile
­­
of
achievability
for
sources
designed
and
operated
to
achieve
emission
levels
equal
to
or
better
than
the
average
of
the
best
performing
sources.
67
Because
of
the
randomness
of
the
emission
values,
there
is
an
associated
probability
of
the
average
of
the
best
performing
sources,
and
similarly
designed
and
operated
sources,
not
passing
the
performance
test
conducted
under
the
same
conditions.
68
At
a
99%
confidence
level,
the
average
of
the
best
performing
sources
could
expect
to
achieve
the
floor
in
99
of
100
future
performance
tests
conducted
under
the
same
conditions
as
its
performance
test..
The
commenter
thus
sharply
mischaracterizes
a
99%
confidence
level
as
the
worst
performance
of
a
best
performing
source.:
the
level
in
fact
assumes
identical
operating
conditions
as
those
of
the
performance
test.
EPA
routinely
establishes
not­
to­
exceed
standards
(
daily
maximum
values
which
cannot
be
exceeded
in
any
compliance
test)
using
the
99%
confidence
level.
National
Wildlife
Federation
v.
EPA,
286
F.
3d
554,
572
(
D.
C.
Cir.
2002).
69
At
a
confidence
level
of
only
97%
for
example,
the
average
of
the
best
performing
sources
could
expect
to
achieve
the
floor
in
only
97
of
100
future
performance
tests.
We
note
that
the
choice
of
a
confidence
level
is
not
a
choice
regarding
the
stringency
of
the
emission
standard.
Although
the
numerical
value
of
the
floor
increases
with
the
confidence
level
selected
it
only
appears
to
become
less
stringent.
If
EPA
selected
a
lower
confidence
interval,
we
would
necessarily
adjust
the
standard
downward
due
to
the
expectation
that
a
source
would
not
be
expected
to
achieve
the
standard
for
uncontrollable
reasons
a
larger
per
cent
of
the
time.
We
would
then
have
to
account
in
some
manner
for
this
inability
to
achieve
the
standard.
See
Weyerhaeuser
v.
Costle,
590
F.
2d
1011,
1056­
57
(
D.
C.
Cir.
1978)
(
also
upholding
standards
established
at
99
%
confidence
level).
The
governing
issue
is
what
level
of
confidence
should
the
average
of
the
best
performing
sources,
and
similarly
designed
and
operated
sources,
have
of
passing
the
performance
test
demonstrating
compliance
with
the
standard.
We
believe
that
the
99%
confidence
level
is
a
confidence
level
within
the
range
of
values
we
could
have
reasonably
selected.
70
d.
Considering
Intersource
Variability
by
Pooling
Run­
to­
Run
Variability
is
Appropriate.
The
commenter
believes
that
any
attempt
by
EPA
to
add
a
variability
factor
to
adjust
for
intersource
variability
is
unlawful
and
arbitrary
and
capricious.
We
see
no
statutory
prohibition
in
considering
intersource
run­
to­
run
variability
of
the
best
performing
67
Note,
again,
that
the
variability
we
quantify
by
these
analyses
is
within­
test
condition
variability
only.
We
cannot
quantify
test­
to­
test
variability
and
thus
cannot
quantify
sources'
total
variability.
68
See
Volume
III
of
the
Technical
Support
Document,
Section
7.2
.
69
The
opinion
notes
further
that
percentiles
for
standards
expressed
as
long­
term
average
typically
use
a
lower
confidence
level
(
usually
95
%
c)
due
to
the
opportunity
to
lower
the
overall
distribution
with
multiple
measurements.
286
F.
3d
at
573.
The
standards
in
this
rule
are
necessarily
daily
maximum
standards
because
continuous
emissions
monitors
for
HAP
do
not
exist
or
have
not
been
demonstrated
on
all
types
of
Subpart
EEE
sources.
70
See
also
Chemical
Mfrs.
Ass'n
v.
EPA,
870
F.
2d
at
229
(
99th
percentile
daily
variability
factor
is
reasonable);
227
("
the
choice
of
statistical
methods
is
committed
to
the
sound
discretion
of
the
Administrator").
sources
(
which
is
all
our
floor
calculation
does,
by
considering
the
pooled
run­
to­
run
variability
of
the
best
performing
sources).
Section
112(
d)(
3)
states
that
MACT
floors
are
to
reflect
the
"
average
emission
limitation
achieved"
but
does
not
specify
any
single
method
of
ascertaining
an
average.
Considering
the
average
run­
to­
run
variability
among
the
group
of
best
performing
sources
is
well
within
the
language
of
the
provision
(
and
was
upheld
in
CMA,
as
noted
above;
see
870
F.
2d
at
228).
The
commenter's
further
argument
that
'
average'
can
only
mean
average
of
emission
levels
achieved
in
performance
tests
is
inconsistent
with
the
holding
in
Mossville,
370
F.
3d
at
1242,
that
EPA
must
account
for
variability
in
developing
MACT
floors
and
that
individual
performance
tests
do
not
by
themselves
account
for
such
variability.
We
believe
that
it
is
reasonable
and
necessary
to
account
for
intersource
variability
of
the
best
performing
sources
by
taking
the
pooled
average
of
the
best
performing
sources'
runto
run
variability.
This
is
an
aspect
of
identifying
the
average
performance
of
those
sources.
Emissions
data
for
each
best
performing
source
are
random
in
nature,
and
this
random
nature
is
characterized
by
a
stochastic
distribution.
The
stochastic
distribution
is
defined
by
its
central
tendency
(
average
value)
and
the
amount
of
dispersion
from
the
point
of
central
tendency
(
variance
or
standard
deviation).
Consequently,
to
define
the
performance
of
the
average
of
the
best
performing
sources,
we
must
consider
the
average
of
the
average
emissions
for
the
best
performing
sources
as
well
as
the
pooled
variance
for
those
sources.
Hence,
we
must
consider
intersource
variability
to
identify
the
floor­­
the
average
performance
of
the
best
performing
sources.
The
commenter
further
states
that
EPA's
attempt
to
adjust
for
intersource
variability
is
unlawful,
arbitrary,
and
capricious.
EPA
set
floors
at
the
99th
percentile
worst
emission
level
that
it
believed
any
source
within
the
group
of
best
performers
could
achieve,
according
to
the
commenter.
The
99th
percentile
worst
performance
that
could
be
expected
from
a
source
within
the
best
performers
is,
simply
put,
not
the
average
performance
of
the
sources
in
that
group,
according
to
the
commenter.
The
commenter
misunderstands
our
approach
to
calculate
the
floor
 
the
floor
is
not
the
99th
percentile
highest
emission
level
that
any
best
performing
source
could
achieve.
The
floor
for
existing
sources
is
calculated
as
the
99th
percentile
modified
upper
prediction
limit
of
the
average
of
the
best
performing
sources.
It
represents
the
average
of
the
best
performing
sources'
emissions
levels
plus
the
pooled
within­
test
condition
variance
of
the
best
performing
sources.
The
floor
for
existing
sources
is
not
the
highest
99th
percentile
upper
prediction
limit
for
any
best
performing
source
as
the
commenter
states.
e.
Why
isn't
Total
Variability
Already
Accounted
for
by
Compliance
Test
Conditions?
Comment:
One
commenter
states
that
EPA's
use
of
variability
factors
along
with
worst­
case
data
is
unlawful
and
arbitrary
and
capricious.
EPA
has
stated
that
its
use
of
worst
case
"
compliance"
data
accounts
for
variability.
EPA
admits
that
compliance
data
reflect
special
worst
case
conditions
created
artificially
for
the
purpose
of
obtaining
lenient
permit
limits,
according
to
the
commenter.
EPA
provides
no
reason
whatsoever
to
believe
that
a
source
would
continue
to
operate
under
such
conditions
even
one
percent
of
the
time.
Thus,
the
commenter
concludes,
by
applying
a
99
percent
variability
factor
to
compliance
test
data,
EPA
ensures
that
the
adjusted
data
do
not
accurately
reflect
the
performance
of
any
source.
Accordingly,
EPA's
use
of
a
variability
factor
is
unlawful.
The
commenter
also
states
that,
to
increase
compliance
data
with
the
reality
that
sources
will
not
be
operating
under
the
worst
case
conditions
except
during
permit
setting
tests,
the
Agency's
use
of
a
variability
factor
with
compliance
data
is
arbitrary
and
capricious.
Response:
All
but
two
standards
in
the
final
rule
are
based
on
compliance
test
data­­
when
sources
maximized
operating
parameters
that
affect
emissions
to
reflect
variability
of
those
parameters
and
to
achieve
emissions
at
the
upper
end
of
the
range
of
normal
operations.
Use
of
these
data
is
appropriate
both
because
they
are
data
in
EPA's
possession
for
purposes
of
section
112(
d)(
3)
and
because
these
data
help
account
for
best
performing
sources'
operating
variability.
CKRC,
255
F.
3d
at
867.
The
main
thrust
of
the
comment
is
that
total
variability
is
accounted
for
by
the
conditions
of
the
performance
test,
so
that
making
further
adjustments
to
allow
for
additional
variability
is
improper.
The
commenter
believes
that
the
floor
should
be
calculated
simply
as
the
average
emissions
of
the
best
performing
sources
and
that
this
floor
would
encompass
the
range
of
operations
of
the
average
of
the
best
performing
sources.
We
disagree.
The
compliance
test
is
designed
to
mirror
the
outer
end
of
the
controllable
variability
occurring
in
normal
operations.
These
controllable
factors
include
the
amount
of
HAP
fed
to
a
source
in
hazardous
waste,
and
controllable
operating
parameters
on
pollution
control
equipment
(
such
as
power
input
to
ESPs,
or
pressure
drop
across
wet
scrubbers,
factors
which
are
reflected
in
the
parametric
operating
limits
written
into
the
source's
permit
and
which
are
based
on
the
results
of
the
compliance
testing).
However,
this
is
plainly
not
all
of
the
variability
a
source
experiences.
Other
components
of
run­
to­
run
variability,
including
variability
relating
to
measuring
(
both
stack
measurements
and
measurements
at
analytic
laboratories)
are
not
reflected,
for
example.
Nor
is
test­
to­
test
variability
reflected,
notably
the
point
in
the
maintenance
cycle
that
testing
is
conducted
and
the
variability
associated
with
those
inherently
differing
test
conditions
even
though
the
source
attempts
to
replicate
the
test
conditions
(
e.
g.,
measurement
variability
attributable
to
use
of
a
different
test
crew
and
analytical
laboratory
and
different
weather
conditions
such
as
ambient
temperature
and
moisture).
Other
changes
that
occur
over
time
are
due
to
a
wide
variety
of
factors
related
to
process
operation,
fossil
fuels,
raw
materials,
air
pollution
control
equipment
operation
and
design,
and
weather.
Sampling
and
analysis
variations
can
also
occur
from
test
to
test
(
above
and
beyond
those
accounted
for
when
assessing
within­
test
variability)
due
to
differences
in
emissions
testing
equipment,
sampling
crews,
weather,
and
analytical
laboratories
or
laboratory
technicians.
Thus,
there
is
some
need
for
a
standard
to
account
for
this
additional
variability,
and
not
simply
expect
for
a
single
performance
test
to
account
for
it.
The
analyses
in
Sections
16
and
17
of
Volume
III
of
the
Technical
Support
Document
confirm
these
points.
Moreover,
the
best
performing
sources
(
and
the
average
of
the
best
performers)
must
be
able
to
replicate
the
compliance
test
if
they
are
to
be
able
to
continue
operating
under
their
full
range
of
normal
operations.
It
is
thus
no
answer
to
say
that
the
best
performing
sources
could
operate
under
a
more
restricted
set
of
conditions
in
subsequent
performance
tests
and
still
demonstrate
compliance,
so
that
there
is
no
need
to
assure
that
results
of
initial
performance
tests
can
be
replicated.
To
do
so
would
no
longer
allow
the
best
performing
sources
(
and
thus
the
average
of
the
best
performing
sources)
to
operate
under
their
full
range
of
normal
operations,
and
thus
impermissibly
would
fail
to
account
for
their
total
variability.
As
discussed
throughout
this
preamble,
emissions
variability
 
run­
to­
run
and
test­
totest
variability­­
is
real
and
must
be
accounted
for
if
a
best
performing
source
is
to
be
able
to
replicate
the
emissions
achieved
during
the
initial
compliance
test.
We
consequently
conclude
that
we
must
account
for
variability
in
establishing
floor
levels,
and
that
merely
considering
the
average
of
compliance
test
data
fails
to
do
so.
We
have
therefore
quantified
run­
to­
run
variability
using
standard
statistical
methodologies,
and
accounted
for
test­
to­
test
variability
either
by
quantifying
it
(
in
the
case
of
fabric
filter
particulate
matter
removal
performance)
or
accounting
for
it
qualitatively
(
in
the
case
of
the
SRE/
feed
ranking
methodology).
Comment:
The
commenter
notes
that
if
EPA
believes
that
single
performance
test
results
do
not
accurately
capture
source's
variability,
the
solution
is
to
gather
more
data,
not
to
avoid
using
a
straight
emissions
methodology.
EPA
cannot
use
this
as
an
excuse
for
basing
floor
levels
on
a
chosen
technology
rather
than
the
performance
of
the
best
performing
sources.
Response:
There
is
no
obligation
for
EPA
to
gather
more
performance
data,
since
the
statute
indicates
that
EPA
is
to
base
floor
levels
on
performance
of
sources
"
for
which
the
Administrator
has
emissions
information."
Section
112
(
d)
(
3)
(
A);
CKRC,
255
F.
3d
at
867
(
upholding
EPA's
decision
to
use
the
compliance
test
data
in
its
possession
in
establishing
MACT
standards).
Indeed,
the
already­
tight
statutory
deadlines
for
issuing
MACT
standards
would
be
even
less
feasible
if
EPA
took
further
time
in
data
gathering.
EPA
notes
further
that
because
particulate
matter
continuous
emission
monitors
are
not
widely
used,
even
further
data
gathering
would
be
limited
to
snapshot,
single
performance
test
results,
still
leaving
the
problem
of
estimating
variability
from
a
limited
data
set.
71
See
also
Sierra
Club
v.
EPA,
167
F.
3d
at
662
("
EPA
typically
has
wide
latitude
in
determining
the
extent
of
datagathering
necessary
to
solve
a
problem").
Thus,
EPA
has
no
choice
but
to
assess
best
performers
and
their
level
of
performance
on
the
basis
of
limited
amounts
of
data
per
source.
As
explained
in
the
previous
response
to
comments,
EPA
has
selected
a
methodology
that
reasonably
do
so.
EPA
notes
further
that
it
has
carefully
examined
those
instances
where
there
are
multiple
test
conditions
(
usually
compliance
tests
conducted
at
different
times)
for
sources
ranked
as
best
performing.
This
analysis
confirms
EPA's
engineering
judgment
that
total
variability
is
not
fully
encompassed
in
the
single
test
condition
results
used
to
identify
these
sources
as
best
performing,
and
that
without
taking
this
additional
variability
into
account,
best
performing
sources
would
be
unable
to
achieve
the
floor
standard
reflecting
their
own
performance
in
those
single
test
conditions.
72
2.
Universal
Variability
Factor
for
Particulate
Emissions
Controlled
with
a
Fabric
Filter
Comment:
One
commenter
states
that,
in
calculating
the
universal
variability
factor
(
UVF)
to
account
for
total
variability­­
test­
to­
test
variability
and
within­
test
variability­­
for
sources
controlling
particulate
matter
with
a
fabric
filter,
it
appears
that
EPA
considered
the
variability
of
sources
that
are
not
best
performing
sources.
If
so,
EPA
has
contravened
the
law.
The
commenter
also
states
that
EPA's
attempt
to
use
a
variability
factor
derived
from
an
analysis
of
variability
of
multiple
sources
is
unlawful.
If
EPA
considers
variability
at
all,
it
must
consider
the
relevant
source's
variability.

71
Performance
tests
take
an
average
of
5­
8
days
to
conduct,
and
cost
approximately
from
$
200,000
 
$
500,000
per
test.
The
commenter's
off­
hand
suggestion
appears
to
have
ignored
these
realities.
72
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,",
September
2005,
Sections
16
and
17.
Response:
We
developed
the
particulate
matter
UVF
for
sources
equipped
with
a
fabric
filter
using
data
from
best
performing
sources
only.
73
It
is
reasonable
to
aggregate
particulate
matter
emissions
data
across
source
categories
for
all
best
performing
sources
equipped
with
a
fabric
filter
because
the
relationship
between
standard
deviation
and
emissions
of
particulate
matter
is
not
expected
to
be
impacted
by
the
source
category
type.
74
Rather,
particulate
emissions
from
fabric
filters
are
a
function
of
seepage
(
i.
e.,
migration
of
particles
through
the
filter
cake)
and
leakage
(
i.
e.,
particles
leaking
through
pores,
channels,
or
pinholes
formed
as
the
filter
cake
builds
up).
The
effect
of
seepage
and
leakage
on
emissions
variability
should
not
vary
across
source
categories.
75
Put
another
way,
fabric
filter
particulate
matter
reduction
is
relatively
independent
of
inlet
loadings
to
the
fabric
filter.
69
FR
21233.
This
is
confirmed
by
the
fact
that
there
are
no
operating
parameters
that
can
be
readily
changed
to
increase
emissions
from
fabric
filters,
id.,
so
control
efficiencies
reflected
in
test
conditions
from
different
source
types
will
still
accurately
reflect
fabric
filter
control
efficiency.
3.
Test­
to­
Test
Variability
Comment:
Several
commenters
state
that
EPA
seems
to
have
ignored
test­
to­
test
variability
resulting
from
changes
that
occur
over
time
such
as:
normal
and
natural
changes
in
a
wide
variety
of
factors
related
to
process
operation,
fuels,
raw
materials,
air
pollution
control
equipment
operation
and
design,
and
differences
in
emissions
testing
equipment,
sampling
crews,
weather,
analytical
laboratories
or
laboratory
technicians.
All
these
sources
of
variation
are
expected
in
that
they
are
typical
and
are
not
aberrations.
In
addition,
there
are
unexpected
sources
of
variability
that
occur
in
real­
world
operations,
which
also
must
be
accommodated
according
to
commenters.
Commenters
state
that
using
compliance
test
data
and
assessing
within­
test
condition
variability
(
i.
e.,
run
variance)
do
not
fully
account
for
test­
to­
test
variability
and
thus
understates
total
variability.
Consequently,
the
average
of
the
best
performing
sources
may
not
be
able
to
achieve
the
same
emission
level
under
a
MACT
performance
test
when
attempting
to
operate
under
the
same
conditions
as
it
did
during
the
compliance
test
EPA
used
to
establish
the
floor.
Even
though
sources
generally
operated
at
the
extreme
high
end
of
the
range
of
normal
operations
during
the
compliance
tests
EPA
uses
to
establish
the
standards,
the
average
of
the
best
performing
sources
would
need
to
operate
under
those
same
compliance
test
conditions
to
establish
the
same
operating
envelope
 
the
operating
envelope
needed
to
ensure
the
source
can
operate
under
the
full
range
of
normal
emissions.
Response:
We
agree
with
commenters
that
we
have
not
quantified
test­
to­
test
variability
when
establishing
the
floors
for
standards
other
than
particulate
matter
where
a
best
performing
source
uses
a
fabric
filter.
We
are
able
to
quantify
only
within­
test
variability
(
i.
e.,
run­
to­
run
variability)
for
the
other
floors,
which
is
only
one
component
of
total
variability.
This
is
one
reason
we
use
the
SRE/
Feed
approach
wherever
possible
rather
than
a
straight
emissions
approach
to
rank
the
best
performing
sources
to
calculate
the
floor
 
the
SRE/
Feed
ranking
approach
derives
floors
that
better
estimate
the
levels
of
best
73
USEPA,
"
Draft
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,",
March
2004,
p.
5­
4.
74
In
addition,
emissions
are
not
generally
affected
by
particulate
inlet
loading.
75
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
5.3.
performing
sources'
performance.
See
also
discussion
in
Part
Four,
Section
III.
A,
and
the
discussion
below
documenting
that
test­
to­
test
variability
can
be
substantial.
Comment:
One
commenter
states
that
EPA
should
use
the
universal
variability
factor
(
UVF)
that
accounts
for
total
variability
for
particulate
matter
controlled
with
a
fabric
filter
to
derive
a
correction
factor
to
account
for
the
missing
test­
to­
test
variability
component
of
variability
for
semivolatile
metals
and
low
volatile
metals.
The
commenter
then
suggests
that
the
within­
test
variability
for
semivolatile
and
low
volatile
metals
be
adjusted
upward
by
the
correction
factor
to
correct
for
the
missing
test­
to­
test
variability
component.
The
commenter
focused
on
cement
kilns
and
compared
the
total
variability
imputed
from
the
UVF
for
the
three
cement
kiln
facilities
used
to
establish
the
UVF
to
the
within­
test
variability
(
i.
e.,
run
variance)
for
each
facility.
The
commenter
determined
that,
on
average
for
the
three
facilities,
total
variability
was
a
factor
of
4.2
higher
than
within­
test
variability.
Because
semivolatile
and
low
volatile
metals
are
also
controlled
with
a
fabric
filter,
the
commenter
suggested
that
the
total
variability
of
particulate
matter
could
be
used
as
an
estimate
of
the
total
variability
for
semivolatile
and
low
volatile
metals.
Thus,
the
commenter
suggested
that
the
within­
test
condition
variability
for
semivolatile
and
low
volatile
metals
be
increased
by
a
factor
of
4.2
to
account
for
total
variability
when
calculating
floors.
Response:
As
stated
throughout
this
preamble,
we
believe
that
there
is
variability
in
addition
to
within­
test
condition
(
i.
e.,
run­
to­
run)
variability
that
we
cannot
quantify
 
that
we
refer
to
as
test­
to­
test
variability.
We
also
do
not
believe
this
test­
to­
test
variability
is
captured
by
compliance
test
operating
conditions
as
discussed
above,
and
thus
establishing
the
floor
using
emissions
data
representing
the
extreme
high
end
of
the
range
of
normal
emissions
does
not
account
for
test­
to­
test
variability.
We
disagree,
however,
with
the
commenter's
attempts
to
quantify
the
remaining
test­
to­
test
variability
for
floors
other
than
particulate
matter
where
all
best
performing
sources
are
equipped
with
fabric
filters.
We
generally
agree
with
the
commenter's
approach
for
extracting
the
test­
to­
test
component
of
variability
using
the
UVF
curve
for
particulate
matter
controlled
with
a
fabric
filter.
76
The
commenter
has
documented
that
for
cement
kilns,
test­
to­
test
variability
of
particulate
emissions
controlled
with
a
fabric
filter
is
on
average
a
factor
of
4.2
higher
than
within­
test
variability.
We
believe
the
commenter's
suggestion
to
adopt
this
correction
factor
to
semivolatile
and
low
volatile
metals
is
technically
flawed
and
for
several
reasons
would
present
statistical
difficulties.
First,
total
variability
for
semivolatile
metals
and
low
volatile
metals
controlled
with
a
fabric
filter
can
be
different
from
the
total
variability
of
particulate
matter
controlled
with
a
fabric
filter
because:
(
1)
the
test
methods
are
different
(
i.
e.,
Method
5
for
particulate
matter
and
Method
29
for
metals)
and
thus
sample
extraction
and
analysis
methods
differ;
(
2)
the
factors
that
affect
partitioning
of
particulate
matter
to
combustion
gas
(
i.
e.,
entrainment)
are
different
from
the
factors
that
affect
semivolatile
metal
partitioning
to
the
combustion
gas
(
i.
e.,
metal
volatility);
and
(
3)
the
volatility
of
semivolatile
metals
is
affected
by
chlorine
feedrates.

76
We
note,
however,
that
an
argument
could
be
made
for
using
a
source
or
condition­
specific
correction
factor
rather
than
averaging
the
correction
factors
for
all
sources
within
a
source
category.
Second,
adopting
a
variability
factor
applicable
to
fabric
filters
for
use
on
electrostatic
precipitators77
is
problematic
because
both
test­
to­
test
and
within­
test
variability
of
these
emission
control
devices
can
be
vastly
different.
Factors
that
affect
emissions
variability
for
sources
equipped
with
a
fabric
filter
include:
(
1)
bag
wear
and
tear
due
to
thermal
degradation
and
chemical
attack;
and
(
2)
variability
in
flue
gas
flowrate.
Factors
that
affect
emissions
variability
for
sources
equipped
with
an
electrostatic
precipitator
are
different
(
see
discussion
in
Section
III.
B
above)
and
include:
variations
in
particle
loading
and
particle
size
distribution,
erosion
of
collection
plates,
and
variation
in
fly
ash
resistivity
due
to
changes
atmospheric
moisture
and
in
sulfur
feedrate
(
e.
g.
different
type
of
coal).
Finally,
the
approach
raises
several
difficult
statistical
questions
including:
(
1)
what
is
the
appropriate
number
of
runs
to
use
to
identify
the
degrees
of
freedom
and
the
t­
statistic
in
the
floor
calculations
(
e.
g.,
should
we
use
the
number
of
runs
available
for
metals
emissions
for
the
source
or
the
number
of
runs
available
for
particulate
matter
emissions
from
which
the
correction
factor
is
derived);
and
(
2)
should
we
use
a
generic
correction
factor
for
all
source
categories
or
calculate
source
category­
specific
or
source­
specific
correction
factors.
For
these
reasons,
we
believe
the
approach
we
use
for
quantifying
baghouse
particulate
matter
collection
variability
is
not
readily
transferable
to
other
types
of
control
devices
and
other
HAP.
We
therefore
are
not
applying
a
quantified
correction
factor
in
the
final
rule
but
rather
are
using
a
MACT
ranking
methodology
that
qualitatively
accounts
for
total
emission
variability,
notably
test­
to­
test
variability.

B.
SRE/
Feed
Methdology
1.
Description
of
the
Methodology
As
proposed,
we
are
using
the
System
Removal
Efficiency
(
SRE)/
Feed
approach
to
determine
the
pool
of
best
performing
sources
for
those
HAP
whose
emissions
can
be
controlled
in
part
by
controlling
the
hazardous
waste
feed
of
the
HAP
 
that
is,
controlling
the
amount
of
HAP
in
the
hazardous
waste
fed
to
the
source.
These
are
HAP
metals
and
chlorine.
Our
basic
approach
is
to
determine
the
sources
in
our
database
with
the
lowest
hazardous
waste
feedrate
of
the
HAP
in
question
(
semi­
volatile
metals,
low
volatile
metals,
mercury,
or
chlorine),
and
the
sources
with
the
best
system
removal
efficiency
for
the
same
HAP.
The
system
removal
efficiency
is
a
measure
of
the
percentage
of
HAP
that
is
removed
prior
to
being
emitted
relative
to
the
amount
fed
to
the
unit
from
all
inputs
(
hazardous
waste,
fossil
fuels,
raw
materials,
and
any
other
input).
The
pool
of
best
performing
sources
are
those
with
the
best
combination
of
hazardous
waste
feedrate
and
system
removal
efficiency
as
determined
by
our
ranking
procedure,
separate
best
performer
pools
being
determined
for
each
HAP
in
question
(
SVM,
LVM,
mercury,
and
chlorine),
reflecting
the
variability
inherent
in
each
of
these
ranking
factors
(
see
A.
2.
a.(
1)
above).
We
then
use
the
emission
levels
from
these
sources
to
calculate
the
emission
level
achieved
by
the
average
of
the
best
performing
sources,
as
also
explained
in
the
previous
section.
This
is
the
MACT
floor
for
the
HAP
from
the
source
type.
For
new
sources,
we
use
the
same
methodology
but
select
the
emission
level
(
adjusted
statistically
to
account
for
quantifiable
variability)
of
the
source
with
77
We
infer
that
the
commenter
suggests
that
we
use
this
correction
factor
for
semivolatile
and
low
volatile
metals
controlled
by
both
electrostatic
precipitators
and
fabric
filters
since
the
majority
of
cement
kilns
are
equipped
with
electrostatic
precipitators.
the
best
combined
ranking.
A
more
detailed
description
of
the
methodology
is
found
in
Volume
III
of
the
Technical
Support
Document,
section
7.3.
This
methodology
provides
a
reasonable
estimate
of
the
best
performing
sources
and
their
level
of
performance
for
HAP
susceptible
to
hazardous
waste
feed
control.
As
required
by
section
112(
d)(
2),
EPA
has
considered
measures
that
reduce
the
volume
of
emissions
through
process
changes,
or
that
prevent
pollutant
release
through
capture
at
the
stack,
and
assessed
how
these
control
measures
are
used
in
combination.
Section
112(
d)(
2)(
A),
(
C)
and
(
E).
Hazardous
waste
feed
control
is
clearly
a
process
change
that
reduces
HAP
emissions;
air
pollution
control
systems
collect
pollutants
at
the
stack.
These
are
the
best
systems
and
measures
for
controlling
HAP
emissions
from
hazardous
waste
combustors.
69
FR
at
21226.
In
considering
these
factors,
EPA
has
necessarily
considered
such
factors
as
design
of
different
air
pollution
control
devices,
waste
composition,
pollution
control
operator
training
and
behavior,
and
use
of
pollution
control
devices
and
methodologies
in
combination.
CKRC,
255
F.
3d
at
864­
65
(
noting
these
as
factors,
in
addition
to
a
particular
type
of
air
pollution
control
device,
that
can
influence
pollution
control
performance);
69
FR
at
21223
n.
47
(
system
removal
efficiency
measures
all
internal
control
mechanisms
as
well
as
back­
end
emission
control
device
performance).
EPA
also
believes
that
this
methodology
reasonably
estimates
the
best
performing
sources'
level
of
performance
by
accounting
for
these
sources'
total
variability,
including
their
performance
over
time.
The
methodology
quantifies
run­
to­
run
variability.
See
69
FR
at
21232­
33.
It
does
not
quantify
test­
to­
test
variability
because
we
are
unable
to
do
so
for
these
pollutants.
(
See
sections
A.
2.
a.(
2)
and
3
above.)
Although
all
variability
must
be
accounted
for
when
calculating
floors,
the
only
definitive
way
to
accurately
quantify
this
testto
test
emissions
variability
is
through
evaluation
of
long­
term
continuous
emissions
monitoring
data,
which
do
not
presently
exist.
We
believe,
however,
that
SRE/
Feed
methodology
provides
some
margin
for
estimating
this
additional,
non­
quantifiable
variability.
This
is
illustrated
in
the
technical
support
document
(
volume
III
section
17),
which
clearly
shows
that
the
straight
emissions
approach
underestimates
(
indeed,
fails
to
account
for)
lower
emitting
sources'
long­
term
emissions
variability.
These
lower
emitting
sources
that
would
otherwise
not
meet
the
floor
levels
on
individual
days
under
the
straight
emission
approach
would
be
able
(
or
otherwise
are
more
capable)
to
do
so
under
the
SRE/
feed
approach.
EPA
further
believes
that
the
SRE/
Feed
methodology
appropriately
accounts
for
design
variability
that
exists
across
sources
for
categories,
like
those
here,
which
consist
of
a
diverse
and
heterogeneous
mixture
of
sources.
This
is
especially
true
of
incinerators
and
boilers,
for
which
there
are
smaller
on­
site
units
that
are
located
at
widely
varying
industrial
sectors
that
essentially
combust
single,
or
multiple
wastestreams
that
are
specific
to
their
industrial
process,
and
off­
site
commercial
units
dealing
with
many
different
wastes
of
different
origins
and
HAP
metal
and
chlorine
composition.
EPA
believes
that
these
variations
are
best
encompassed
in
the
SRE/
Feed
approach,
rather
than
with
a
subcategorization
scheme
that
could
result
in
anomalous
floor
levels
because
there
are
fewer
sources
in
each
source
subcategory
from
which
to
assess
relative
performance.
78
See
78
At
proposal,
we
conducted
a
technical
analysis
to
determine
potential
subcategorization
options.
We
then
conducted
an
analysis
to
determine
if
these
different
types
of
sources
exhibited
statistically
different
emissions.
Although
EPA
in
the
end
determined
that
these
source
categories
should
not
be
subcategorized
further,
this
decision
was
based
in
part
because
the
SRE/
Feed
methodology
better
accounts
for
the
range
of
Mossville,
370
F.
3d
at
1240
(
upholding
floor
methodology
involving
reasonable
estimation,
rather
than
use
of
emissions
data,
when
sources
in
the
category
have
heterogeneous
emission
characteristics
due
to
highly
variable
HAP
concentrations
in
feedstocks).
Use
of
the
SRE/
Feed
approach
also
avoids
basing
the
floor
standards
on
a
combination
of
the
lowest
emitting
low
feeding
sources
and
the
lowest
emitting
high
feeding
sources.
For
example,
the
five
lowest
emitting
incinerators
for
semivolatile
metals
that
would
comprise
the
MACT
pool
using
a
straight
emissions
methodology
include
three
sources
that
are
the
first,
second,
and
fourth
lowest
feeding
sources
among
all
the
incinerators.
79
The
other
two
best
performing
incinerators
have
the
first
and
second
best
system
removal
efficiencies
(
and
the
highest
two
metal
feedrates).
It
is
noteworthy
that
the
highest
feed
control
level
among
these
best
performing
sources
is
over
three
orders
of
magnitude
higher
than
the
feed
control
level
of
the
lowest
feeding
best
performing
source.
80
Establishing
limits
dominated
by
both
superior
feed
control
sources
and
back­
end
controlled
sources
would
result
in
floor
levels
that
are
not
reflective
of
the
range
of
emissions
exhibited
by
either
low
feeding
sources
or
high
feeding
sources
and
would
more
resemble
new
source
standards
for
both
of
these
different
types
of
combustors.
Such
floors
could
lead
to
situations,
for
example,
where
commercial
sources
could
find
it
impracticable
to
achieve
the
standards
without
reducing
the
overall
scope
of
their
operations
(
since
the
standard
could
operate
as
a
direct
constraint
on
the
amount
of
hazardous
waste
that
could
be
fed
to
the
device,
in
effect
depriving
a
combustion
source
of
its
raw
material).
Similarly,
low
feeding
sources
that
cannot
achieve
this
floor
level
may
be
required
to
add
expensive
back­
end
control
equipment
that
would
result
in
minimal
emission
reductions,
likely
forcing
the
smaller
on­
site
source
to
cease
hazardous
waste
treatment
operations
and
to
instead
send
the
waste
to
a
commercial
treatment
unit.
The
inappropriateness
of
a
straight
emissions­
based
approach
for
feed
controlled
pollutants
for
commercial
hazardous
waste
combustors
is
further
highlighted
by
the
fact
that
several
commercial
hazardous
waste
combustors
that
are
achieving
the
design
level
of
the
particulate
matter
standard
are
not
achieving
the
semivolatile
and/
or
low
volatile
metals
straight
emissions
based
design
level,
and,
in
some
instances,
floor
level.
81
This
provides
further
evidence
that
low
feeding
sources
are
in
fact
biasing
some
of
the
straight
emissionsbased
floors
to
the
extent
that
even
the
sources
with
the
most
efficient
back­
end
control
devices
would
be
incapable
of
achieving
the
emission
standards
calculated
on
a
straight
emission
basis.
These
results
are
inconsistent
with
the
intent
of
the
section
112
(
d)
(
see
2
Legislative
History
at
3352
(
House
Report)
stating
that
MACT
is
not
intended
to
drive
sources
out
of
business).
Standards
that
could
force
commercial
sources
to
reduce
the
overall
scope
of
their
emissions
from
the
best
performing
sources
for
these
diverse
combustion
types.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
4,
for
an
explanation
of
the
subcategorization
assessment,
which
includes
examples
of
anomalous
floor
results
for
certain
subcategorization
approaches.
79
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Appendix
C,
Table
"
E_
INC_
SVMCT"
and,
to
determine
relative
feed
control
and
SRE
rankings
for
these
sources,
Appendix
E
Table
"
SF_
INC_
SVMCT".
80
Source
340
had
a
semivolatile
metal
feed
control
MTEC
of
892
ug/
dscm,
whereas
source
327
had
a
semivolatile
metal
feed
control
MTEC
of
3,080,571
ug/
dscm.
81
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
17.4
operations
are
also
inconsistent
with
requirements
and
objectives
of
the
Resource
Conservation
and
Recovery
Act
to
require
treatment
of
hazardous
wastes
before
the
wastes
can
be
land
disposed,
and
to
encourage
hazardous
waste
treatment.
RCRA
sections
3004
(
d),
(
e),
(
g)
and
1003
(
a)
(
6);
see
also
section
112
(
n)
(
7)
of
the
CAA,
stating
that
section
112
(
d)
MACT
standards
are
to
be
consistent
with
RCRA
subtitle
C
emission
standards
for
the
same
sources
to
the
maximum
extent
practicable
(
consistent
with
the
requirements
of
section
112
(
d));
moreover,
EPA
doubts
that
a
standard
which
precludes
effective
treatment
mandated
by
a
sister
environmental
statute
must
be
viewed
as
a
type
of
best
performance
under
section
112
(
d).
The
SRE/
Feed
methodology
avoids
this
result
by
always
considering
hazardous
waste
feed
control
in
combination
with
system
removal
efficiency
and
according
equal
weight
to
both
means
of
control
in
the
ranking
process.
It
is
also
important
to
emphasize
what
the
SRE/
Feed
methodology
does
not
evaluate:
feed
control
of
HAP
in
fossil
fuel
or
raw
material
inputs
to
these
devices.
Emission
reduction
of
these
HAP
are
controllable
by
back­
end
pollution
control
devices
which
remove
a
given
percentage
of
pollutants
irrespective
of
their
origin
and
is
assured
by
the
system
removal
efficiency
portion
of
the
methodology,
as
well
as
through
the
particulate
matter
standard
(
see
section
IV.
A
below).
Feed
control
of
these
inputs
is
not
a
feasible
means
of
control,
however.
HAP
content
in
raw
materials
and
fossil
fuel
can
be
highly
variable,
and
so
cannot
even
be
replicated
by
a
single
source.
Raw
material
and
fossil
fuel
sources
are
also
normally
proprietary,
so
other
sources
would
not
have
access
to
raw
material
and
fossil
fuel
available
(
in
its
performance
test)
to
a
source
with
low
HAP
fossil
fuel
and
raw
material
inputs.
Such
sources
would
thus
be
unable
to
duplicate
these
results.
Moreover,
there
are
no
commercial­
scale
pretreatment
processes
available
for
removing
or
reducing
HAP
content
in
raw
materials
or
fossil
fuels
to
these
units.
See
technical
support
document
volume
III
section
17.5
and
25;
see
also
69
FR
at
21224
and
n.
48.
2.
Why
aren't
the
lowest
emitters
the
best
performers?
Some
commenters
nonetheless
argue
that
best
performing
sources
can
only
mean
sources
with
the
lowest
HAP
emissions,
and
that
the
SRE/
Feed
methodology
is
therefore
flawed
because
it
does
not
invariably
select
lowest
emitters
as
best
performers.
82
The
statute
does
not
compel
this
result.
There
is
no
language
stating
that
lowest
emitting
sources
are
by
definition
the
best
performers.
The
floor
for
existing
sources
is
to
be
based
on
the
average
emission
limitation
achieved
by
the
"
best
performing"
12
per
cent
of
sources.
Section
112
(
d)
(
3)
(
A).
This
language
does
not
specify
how
"
best
performing"
is
to
be
determined:
by
means
of
emission
level,
emission
control
efficiency,
measured
over
what
period
of
time,
etc.
See
Sierra
Club
v.
EPA,
167
F.
3d
at
661
(
language
of
floor
requirement
for
existing
sources
"
on
its
own
says
nothing
about
how
the
performance
of
the
best
units
is
to
be
calculated").
Put
another
way,
this
language
does
not
answer
the
question
of
which
source
is
the
better
performing:
one
that
emits
100
units
of
HAP
but
also
feeds
100
units
of
that
HAP,
or
one
that
emits
101
units
of
the
HAP
but
feeds
10,000
units.
See
69
FR
at
21223.
Moreover,
new
source
floors
are
to
be
based
on
the
performance
of
the
"
best
controlled"
similar
source
achieved
in
practice.
Section
112
(
d)
(
3).
"
Best
controlled"
can
naturally
be
read
to
refer
to
some
means
of
control
such
as
system
removal
efficiency
as
well
as
to
emission
level.
Use
of
a
straight
emissions
approach
to
identify
floor
levels
can
lead
to
arbitrary
results.
Most
important,
as
explained
above,
it
leads
to
standards
which
cannot
be
achieved
82
In
fact,
many
of
the
sources
identified
as
best
performing
under
the
SRE/
Feed
methodology
are
also
the
lowest
emitting,
although
this
is
not
invariably
the
case.
consistently
even
by
the
best
performing
sources
because
operating
variability
is
not
accounted
for.
This
is
shown
in
section
17
of
volume
III
of
the
technical
support
document.
These
analyses
show
that
a)
emissions
from
these
sources
do
in
fact
vary
from
test­
to­
test,
and
that
no
two
snapshot
emission
test
results
are
identical;
b)
our
statistical
approach
that
quantifies
within
test,
run­
to­
run
variability
underestimates
the
best
performing
sources'
long
term,
test­
to­
test
variability;
83
c)
best
performing
sources
under
the
straight
emissions
approach
advocated
by
the
commenter
(
i.
e.
the
lowest
emitting
sources)
had
other
test
conditions
that
did
not
achieve
straight
emission
floor
levels;
d)
best
performing
sources
under
the
straight
emissions
approach
are
projected,
based
on
two
separate
analyses
using
reasonable
assumptions,
not
to
achieve
the
straight
emissions
floor
standard
based
on
these
sources'
demonstrated
variations
in
system
removal
efficiencies
over
time
(
i.
e.,
from
test­
totest
and
e)
SRE/
feed
methodology
yields
floor
levels
(
i.
e.
the
floor
standards
in
the
rule)
that
better
estimate
the
emission
levels
reflecting
the
performance
over
time
of
the
best
performing
sources.
See
Mossville,
370
F.
3d
at
1242
(
floor
standard
is
reasonable
because
it
accommodated
best
performing
source's
highest
level
of
performance
(
i.
e.
its
total
variability),
even
though
the
level
of
the
standard
was
higher
than
any
individual
measurement
from
that
source).
As
noted
earlier,
the
straight
emissions
methodology
can
also
limit
operation
of
commercial
units
because
the
standard
reflects
a
level
of
hazardous
waste
feed
control
which
could
force
commercial
units
to
burn
less
hazardous
waste
because
such
standards
more
resemble
new
source
standards.
The
straight
emissions
methodology
also
arbitrarily
reflects
HAP
levels
in
raw
materials
and
fossil
fuels,
an
infeasible
means
of
control
for
any
source.
Another
arbitrary,
and
indeed
impermissible,
result
of
the
straight
emissions
methodology
is
that
in
some
instances
(
noted
in
responses
below)
the
methodology
results
in
standards
which
would
force
sources
identified
as
best
performing
to
install
upgraded
air
pollution
control
equipment.
This
result
undermines
section
112
(
d)
(
2)
of
the
statute,
by
imposing
what
amounts
to
a
beyond
the
floor
standard
without
consideration
of
the
beyond
the
floor
factors:
the
cost
of
achieving
those
reductions,
as
well
as
energy
and
nonair
environmental
impacts.
Comment:
The
commenter
states
that
because
MACT
floors
must
reflect
the
"
actual
performance"
of
the
relevant
best
performing
hazardous
waste
combusters,
this
means
that
the
lowest
emitters
must
be
the
best
performers.
The
commenter
cites
CKRC
v.
EPA,
255
F.
3d
at
862
and
other
cases
in
support.
Response:
As
explained
in
the
introduction
above,
the
statute
does
not
specify
that
lowest
emitters
are
invariably
best
performers.
Nor
does
the
caselaw
cited
by
the
commenter
support
this
position.
The
D.
C.
Circuit
has
held
repeatedly
that
EPA
may
determine
which
sources
are
best
performing
and
may
"
reasonably
estimate"
the
performance
of
the
top
12
percent
of
these
sources
by
means
other
than
use
of
actual
data.
Mossville,
370
F.
3d
at
1240­
41
(
collecting
cases).
In
Mossville,
sources
had
varying
levels
of
vinyl
chloride
emissions
due
to
varying
concentrations
of
vinyl
chloride
in
their
feedstock.
Individual
measurements
consequently
did
not
adequately
represent
these
sources'
performance
over
time.
Not­
to­
exceed
permit
limits
thus
reasonably
estimated
sources'
performance,
corroboration
being
that
individual
sources
with
the
lowest
long­
term
average
performance
83
Best
performing
sources
pursuant
to
the
straight
emissions
methodology
are
projected
to
be
unable
to
achieve
the
level
of
their
of
their
performance
test
emissions
even
after
they
are
adjusted
upward
to
account
for
run­
to­
run
variability.
occasionally
came
close
to
exceeding
those
permit
limits.
Id.
at
1241­
42.
The
facts
are
similar
here,
since
our
examination
of
best
performing
sources
with
multiple
test
conditions
likewise
shows
instances
where
these
sources
would
be
unable
to
meet
floors
established
based
solely
on
lowest
emissions
(
including
their
own).
As
here,
EPA
was
not
compelled
to
base
the
floor
levels
on
the
lowest
measured
emission
levels.
Comment:
The
same
commenter
maintains
that
it
is
clear
from
the
caselaw
that
MACT
floors
must
reflect
the
relevant
best
performing
sources'
`
actual
performance',
and
that
this
must
refer
to
the
emissions
level
it
achieves.
Response:
As
just
stated,
the
D.
C.
Circuit
has
repeatedly
stated
that
EPA
may
make
reasonable
estimates
of
sources'
performance
in
assessing
both
which
sources
are
best
performing
and
the
level
of
their
performance.
The
court
has
further
indicated
that
EPA
is
to
account
for
variability
in
assessing
sources'
performance
for
purposes
of
establishing
floors,
and
this
assessment
may
require
that
EPA
make
reasonable
estimates
of
performance
of
best
performing
sources.
CKRC,
255
F.
3d
at
865­
66;
Mossville,
370
F.
3d
at
1241­
42.
See
discussion
in
A.
1.
a
above.
Comment:
The
commenter
generally
maintains
that
EPA's
floor
approaches
consider
only
the
performance
of
back­
end
pollution
control
technology
and
so
fail
to
capture
other
means
of
HAP
emission
control
that
otherwise
would
be
captured
if
EPA
were
to
assess
performance
based
on
the
emission
levels
each
source
achieved.
Response:
EPA
agrees
that
factors
other
than
end­
of­
stack
pollution
control
can
affect
metal
HAP
and
chlorine
emissions.
This
is
why
EPA
assesses
performance
for
these
HAP
by
considering
combinations
of
system
removal
efficiency
(
which
measures
every
element
in
a
control
system
resulting
in
HAP
reduction,
not
limited
to
efficiency
of
a
control
device),
and
hazardous
waste
HAP
feed
control.
Standards
for
dioxins
and
other
organic
HAP
(
which
have
no
hazardous
waste
feed
control
component)
likewise
assess
every
element
of
control.
EPA
also
accounts
for
the
variability
of
HAP
levels
in
the
(
essential)
use
of
raw
materials
and
fossil
fuels
by
assessing
performance
of
back­
end
control
but
not
evaluating
fuel/
raw
material
substitution,
which,
as
discussed
later
in
the
response
to
comments
section,
are
infeasible
means
of
control.
Mossville,
370
F.
3d
at
1241­
42,
is
instructive
on
this
point.
The
court
held
that
the
constant
change
in
raw
materials
justified
EPA's
use
of
a
regulatory
limit
to
estimate
a
floor
level.
The
reasonableness
of
this
level
was
confirmed
by
showing
that
the
highest
individual
data
point
of
a
best
performing
source
was
nearly
at
the
level
of
the
regulatory
limit.
Under
the
commenter's
approach,
the
court
would
have
had
no
choice
but
to
hold
that
the
level
the
source
achieved
in
a
single
test
result
using
`
clean'
raw
materials
 
i.
e.
the
`
level
achieved'
in
the
commenter's
language
 
dictated
the
floor
level.
See
part
four,
section
III.
C
for
EPA's
response
to
this
comment
as
it
relates
to
the
methodologies
for
the
particulate
matter
standard
and
total
chlorine
standard
for
hydrochloric
acid
production
furnaces.
Comment:
The
commenter
notes
that
the
SRE/
Feed
methodology
does
not
account
for
all
HAP
emissions,
failing
to
account
for
metal
and
chlorine
feedrates
in
raw
materials
and
fossil
fuels.
Response:
The
methodology
does
not
assess
the
effect
of
feed
"
control"
of
HAP
levels
in
raw
materials
or
fossil
fuels
which
may
be
inputs
to
the
combustion
units.
This
is
because
such
control
may
not
be
replicable
by
an
individual
source,
or
duplicable
by
any
other
source.
See
69
FR
at
21224
and
n.
48;
Sierra
Club
v.
EPA,
353
F.
3d
976,
988
("
substitution
of
cleaner
ore
stocks
was
not
...
a
feasible
basis
on
which
to
set
emission
standards.
Metallic
impurity
levels
are
variable
and
unpredictable
both
from
mine
to
mine
and
within
specific
ore
deposits,
thereby
precluding
ore­
switching
as
a
predictable
and
consistent
control
strategy").
84
EPA's
methodology
does
account
for
HAP
control
of
all
inputs
by
assessing
system
removal
efficiency,
which
measures
reductions
of
HAPs
in
all
inputs
(
including
fossil
fuel
and
raw
materials)
to
a
hazardous
waste
combustion
unit.
Further,
nonmercury
metal
HAP
emissions
attributable
to
raw
materials
and
fossil
fuels
are
effectively
controlled
with
the
particulate
matter
standard,
a
standard
that
is
based
on
the
sources
with
best
back­
end
control
devices.
The
only
element
which
is
not
controlled
is
what
cannot
be:
HAP
levels
in
feeds
for
which
fuel
or
raw
material
switching
is
simply
not
an
available
option.
Comment:
The
commenter
further
maintains,
however,
that
the
means
by
which
sources
may
be
achieving
levels
of
performance
are
legally
irrelevant
(
citing
National
Lime
Ass'n
v.
EPA,
233
F.
3d
625
,
634
and
640
(
D.
C.
Cir.
2000)).
The
fact
that
sources
with
`
cleaner'
raw
material
and
fossil
fuel
inputs
may
not
intend
to
have
resulting
lower
HAP
emissions
is
therefore
without
legal
bearing.
Response:
The
issue
here
is
not
one
of
intent.
The
Court,
in
National
Lime,
rejected
the
argument
that
sources'
lack
of
intent
to
control
a
HAP
did
not
preclude
EPA
from
establishing
a
section
112
(
d)
standard
for
that
HAP.
See
233
F.
3d
at
640,
rejecting
the
argument
that
HAP
metal
control
achieved
by
use
of
back­
end
control
devices
(
baghouses)
could
not
be
assessed
by
EPA
because
the
sources
used
the
back­
end
control
devices
to
control
emissions
of
particulate
matter.
The
case
did
not
consider
the
facts
present
here,
where
the
issue
is
not
a
source's
intent,
but
rather
a
means
of
control
which
involves
happenstance
(
composition
of
HAP
in
raw
materials
and
fossil
fuel
used
the
day
the
test
was
conducted)
and
so
is
neither
replicable
nor
duplicable.
National
Lime
also
held
that
EPA
must
establish
a
section
112
(
d)
emission
standard
for
every
HAP
emitted
by
a
major
source.
233
F.
3d
at
634.
EPA
is
establishing
emission
standards
for
all
HAP
emitted
by
these
sources.
In
establishing
these
standards,
EPA
is
not
evaluating
emission
reductions
attributable
to
the
type
of
fossil
fuel
and
raw
material
used
in
the
performance
tests,
because
this
is
not
a
"
feasible
basis
on
which
to
set
emission
standards."
Sierra
Club,
353
F.
3d
at
988.
EPA
thus
does
not
agree
with
this
comment
because
the
issue
is
not
a
source's
intent
but
rather
whether
or
not
to
assess
emission
reductions
from
individual
test
results
which
reflect
an
infeasible
means
of
control.
Comment:
The
commenter
maintains,
however,
that
even
if
individual
sources
(
including
those
in
the
pool
of
best
performing
sources)
cannot
reduce
HAP
concentrations
in
raw
materials
and
fossil
fuels,
they
may
achieve
the
same
reductions
by
adding
back­
end
pollution
control.
Nothing
in
section
112
(
d)
(
3)
says
that
sources
have
to
use
the
means
of
achieving
a
level
of
performance
that
other
best
performing
sources
used.
Response:
The
thrust
of
this
comment
is
essentially
to
impermissibly
bypass
the
beyond­
the­
floor
factors
set
out
in
section
112
(
d)
(
2)
under
the
guise
of
adopting
a
floor
84
Although
this
language
arose
in
the
context
of
a
potential
beyond­
the­
floor
standard,
EPA
believes
that
the
principle
stated
is
generally
applicable.
MACT
standards,
after
all,
are
technology­
based,
and
if
there
is
no
technology
(
i.
e.
no
available
means)
to
achieve
a
standard
 
i.
e.
for
a
source
to
achieve
a
standard
whenever
it
is
tested
(
as
the
rules
require)
 
then
the
standard
is
not
an
achievable
one.
standard.
Suppose
that
EPA
were
to
adopt
a
floor
standard
dominated
by
emission
levels
reflecting
HAP
concentrations
present
in
a
few
sources'
raw
materials
and
fossil
fuels
during
their
test
conditions.
Suppose
further
that
some
sources
have
to
upgrade
their
back­
end
control
equipment
to
operate
at
efficiencies
better
than
the
average
level
demonstrated
by
the
best
performing
sources,
because
test
results
based
on
fossil
fuel
and
raw
material
levels
are
neither
replicable
nor
duplicable.
In
this
situation,
EPA
believes
that
it
would
have
improperly
adopted
a
beyond­
the­
floor
standard
because
EPA
would
have
failed
to
consider
the
beyond­
the­
floor
factors
(
cost,
energy,
and
nonair
environmental
impacts)
set
out
in
section
112
(
d)
(
2).
85
Comment:
EPA
has
not
substantiated
its
claim
that
sources
cannot
switch
fossil
fuels
or
raw
materials.
Response:
At
proposal
we
evaluated
fuel
switching
and
raw
material
substitution
as
beyond­
the­
floor
technologies
for
cement
kilns
and
lightweight
aggregate
kilns
and
stated
these
technologies
would
not
be
cost
effective.
86
We
also
discussed
why
fuel
switching
is
not
an
appropriate
floor
control
technology
for
solid
fuel­
fired
boilers.
69
FR
at
21273.
Upon
further
evaluation,
we
again
conclude
that
fuel
switching
and
raw
material
substitution
are
not
floor
control
technologies
and
are
not
cost
effective
beyond­
the­
floor
technologies
for
cement
kilns,
lightweight
aggregate
kilns,
and
solid
fuel­
fired
boilers.
87
Comment:
EPA
has
failed
to
document
the
basis
for
its
SRE
ranking.
Specifically,
EPA
has
not
stated
how
it
measured
sources'
SREs,
or
how
it
knows
those
rankings
are
accurate.
Response:
System
removal
efficiency
is
a
parameter
that
is
included
in
our
database
that
is
calculated
by
the
following
formula:

(
)(
)
[
]
feedrate
mass
HAP
total
rate
emission
mass
HAP
gas
stack
feedrate
mass
HAP
total
SRE
 
×
=
100
The
HAP
feedrate
and
emission
data
are
components
of
the
database
that
were
extracted
from
emission
test
reports
for
each
source.
We
use
system
removal
efficiency
for
each
relevant
pollutant
or
pollutant
group
(
e.
g.,
semivolatile
metals,
low
volatile
metals,
mercury,
total
chlorine)
whenever
the
data
allows
us
to
calculate
a
reliable
system
removal
efficiency.
For
example,
we
generally
do
not
use
system
removal
efficiencies
that
are
based
on
normal
emissions
data
because
of
the
concern
that
normal
feed
data
are
too
sensitive
to
sampling
and
measurement
error.
See
69
FR
at
21224.88
85
Analysis
of
the
levels
of
HAP
in
raw
material
and
nonhazardous
waste
fuels
suggests
that
this
is
a
realistic
outcome.
Our
analysis
shows
that
emissions
attributable
to
raw
material
and
fossil
fuel
can
be
significant
relative
to
the
level
of
the
straight
emissions­
based
floor
design
level
and
floor
(
the
methodology
advocated
by
the
commenter),
and
therefore
could
inappropriately
impact
a
source's
ability
to
comply
with
such
a
floor
standard.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
17.6.
86
See,
for
example,
69
FR
at
21252,
where
we
discuss
the
use
of
fuel­
switching
or
raw
material
substitution
as
a
possible
beyond­
the­
floor
control
for
mercury
at
cement
kilns.
87
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,
September
2005,
Sections
11
and
25,
for
further
discussion.
88
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
II:
Database,"
September
2005,
Section
2,
for
further
discussion
on
system
removal
efficiencies,
which
includes
sample
The
system
removal
efficiencies
used
in
our
ranking
process
are
reliable
and
accurate
because
the
feed
and
emissions
data
originate
from
compliance
tests
that
demonstrate
compliance
with
existing
emission
standards
(
primarily
RCRA
requirements).
As
such,
the
data
are
considered
to
have
excellent
accuracy
and
quality.
RCRA
trial
burn
and
certification
of
compliance
reports
are
typically
reviewed
in
detail
by
the
permitting
authority.
The
compliance
tests
and
test
reports
generally
contain
the
use
of
various
quality
assurance
procedures,
including
laboratory,
method,
and
field
blanks,
spikes,
and
surrogate
samples,
all
of
which
are
designed
to
minimize
sampling
and
analytical
inaccuracies.
EPA
also
noticed
the
data
base
for
this
rule
for
multiple
rounds
of
comment
and
has
made
numerous
changes
in
response
to
comment
to
assure
accuracy
of
the
underlying
data.
Thus,
EPA
concludes
the
calculated
system
removal
efficiencies
used
in
the
ranking
process
are
both
reliable
and
accurate.
Comment:
EPA's
approach
with
regard
to
use
of
stack
data
is
internally
contradictory.
EPA
uses
stack
data
in
establishing
floors,
but
does
not
use
stack
data
to
determine
which
performers
are
best.
EPA
has
failed
to
explain
this
contradiction.
Response:
Emission
levels
are
used
to
calculate
system
removal
efficiencies
in
order
to
assess
each
source's
relative
back­
end
control
efficiency.
Also,
as
explained
in
the
introduction
to
this
comment
response
section,
the
SRE/
Feed
methodology
uses
the
stack
emission
levels
of
the
sources
using
the
best
combinations
of
hazardous
waste
feed
control
and
system­
wide
air
pollution
control
(
expressed
as
HAP
percent
removal
over
the
entire
system)
to
calculate
the
floors.
The
data
are
adjusted
statistically
to
account
for
quantifiable
forms
of
variability
(
run­
to­
run
variability).
This
methodology
reasonably
selects
best
performing
sources
(
for
HAP
amenable
to
these
means
of
control),
and
reasonably
estimates
these
sources'
performance
over
time.
As
further
stated
in
section
B.
2
above,
using
a
straight
emissions
approach
to
identify
best
performers
and
their
level
of
performance
can
lead
to
standards
for
these
HAP
that
do
not
fully
account
for
variability
(
including
variability
resulting
from
varying
and/
or
uncontrollable
amounts
of
HAP
in
raw
materials
and
fossil
fuels)
and
could
force
installation
of
de
facto
beyond­
the­
floor
controls
without
consideration
of
the
section
112(
d)(
2)
beyond­
the­
floor
factors.
EPA
thus
does
not
see
the
contradiction
expressed
by
the
commenter.
Use
of
the
straight
emissions
approach
as
advocated
by
the
commenter
would
lead
to
standards
that
do
not
reasonably
estimate
sources'
performance
and
which
could
not
be
achieved
even
by
the
best
performers
with
individual
test
conditions
below
the
average
of
the
12
percent
of
best
performing
sources.
These
problems
would
be
compounded
many­
fold
if
the
data
were
not
normalized
and
adjusted
to
at
least
account
for
quantifiable
variability,
steps
the
commenter
also
opposes.
EPA's
use
of
emissions
data
(
suitably
adjusted)
after
identifying
best
performers
through
the
ranking
methodology
avoids
these
problems
and
reasonably
estimates
best
performers'
level
of
performance.
Comment:
The
commenter
rejects
EPA's
finding
(
69
FR
at
21226)
that
individual
test
results
in
the
data
base
do
not
fully
express
the
best
performing
sources'
performance.
The
commenter
gives
a
number
of
reasons
for
its
criticisms,
which
we
answer
in
the
following
sequence
of
comments
listed
a
though
f.
a.
Comment:
The
commenter
states
that
EPA
claims
emission
levels
do
not
fully
reflect
variability
in
part
because
they
are
sometimes
based
on
tests
where
the
source
was
calculations
and
references
to
the
database
that
contain
the
calculated
system
removal
efficiencies
for
each
source
and
each
HAP
or
HAP
group.
feeding
low
levels
of
HAP
during
the
test.
The
commenter
claims
this
is
inconsistent
with
the
fact
that
EPA
preferentially
uses
worst­
case
emissions
obtained
from
tests
where
the
sources
spiked
their
feedstreams
with
metals,
and
that
the
mere
possibility
that
these
emissions
do
not
reflect
test
data
from
conditions
where
variability
was
not
maximized
does
not
mean
those
data
fail
to
represent
a
source's
actual
performance.
The
commenter
also
states
that
"
EPA's
apparent
suggestion
that
the
best
performing
sources
could
not
replicate
the
average
performance
of
the
sources
with
the
lowest
emissions
is
unsubstantiated
and
unexplained.
Assuming
that
EPA
accurately
assesses
a
source's
actual
performance,
the
source
can
replicate
that
performance."
Response:
HAPs
in
raw
materials
and
fossil
fuels
contribute
to
a
source's
emissions.
EPA
has
concerns
that
a
straight
emissions
approach
to
setting
floors
may
not
be
replicable
by
the
best
performing
sources
nor
duplicable
by
other
non­
best
performing
sources
because
of
varying
concentration
levels
of
HAP
in
raw
material
and
nonhazardous
waste
fuels.
The
best
performing
sources
operated
under
compliance
test
conditions
as
the
commenter
suggests.
However,
raw
material
and
nonhazardous
fuel
HAP
concentrations
for
the
best
performing
sources
will
change
over
time,
perhaps
due
to
a
different
source
of
fuel
or
raw
material
quarry
location,
which
could
affect
their
ability
to
achieve
the
floor
level
that
was
based
on
emissions
obtained
while
processing
different
fossil
fuel
or
raw
materials.
EPA
takes
sharp
issue
with
the
commenter's
statement
that
a
single
performance
test
result
is
automatically
replicable
so
long
as
it
is
measured
properly
in
the
first
instance.
This
statement
is
incorrect
even
disregarding
HAP
contributions
in
raw
materials
and
fossil
fuels
since,
as
noted
previously
in
section
A.
2.
e
,
there
are
many
other
sources
of
variability
which
will
influence
sources'
performance
over
time
(
i.
e.,
in
subsequent
performance
tests).
A
straight
emissions
approach
for
establishing
semivolatile
and
low
volatile
metal
floors
may
result
in
instances
where
the
best
performing
sources
would
not
be
capable
of
achieving
the
standards
if
their
raw
material
and
nonhazardous
waste
fuel
HAP
levels
change
over
time.
For
each
cement
kiln
and
lightweight
aggregate
kiln,
we
estimated
the
emissions
attributable
to
these
raw
materials
and
fossil
fuels
assuming
each
source
was
operating
with
hazardous
waste
HAP
feed
and
back­
end
control
levels
equivalent
to
the
average
of
the
best
performing
sources
(
the
difference
in
emissions
across
sources
only
being
the
result
of
the
differing
HAP
levels
in
the
nonhazardous
waste
feeds).
The
analysis
shows
that
emissions
attributable
to
these
nonhazarous
waste
feedstreams
(
raw
materials
and
fossil
fuels)
varies
across
sources,
and
can
be
significant
relative
to
the
level
of
the
straight
emissions­
based
floor
design
level
and
floor,
and
therefore
could
inappropriately
impact
a
source's
ability
to
comply
with
the
floor
standard.
89
b.
Comment:
The
commenter
states
that
EPA
must
consider
contributions
to
emissions
from
raw
materials
and
fossil
fuels,
that
it
is
irrelevant
if
sources
from
outside
the
pool
of
best
performing
sources
can
duplicate
emission
levels
reflecting
`
cleaner'
raw
materials
and
fossil
fuels
used
by
the
best
performing
sources,
and
that
sources
unable
to
obtain
such
`
cleaner'
inputs
may
always
upgrade
other
parts
of
their
systems
to
achieve
that
level
of
performance.
Response:
As
previously
discussed,
EPA's
methodology
does
account
for
HAP
control
of
all
inputs
by
assessing
system
removal
efficiency,
which
measures
reductions
of
89
See
USEPA,
"
Final
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
17.6.
.
HAPs
from
all
inputs.
Further,
nonmercury
metal
HAP
emissions
attributable
to
raw
materials
and
fossil
fuels
are
effectively
controlled
with
the
particulate
matter
standard,
a
standard
that
is
based
on
the
sources
with
lowest
emissions
from
best
back­
end
control
devices.
We
are
not
basing
any
standards
on
performance
of
sources
not
ranked
as
among
the
best
performing.
c.
Comment:
The
commenter
disputes
EPA's
conclusions
that
failure
of
sources
to
meet
all
of
the
standards
based
on
a
straight
emissions
methodology
at
once
shows
that
the
methodology
is
flawed.
The
standards
are
not
mutually
dependent,
so
the
fact
that
they
are
not
achieved
simultaneously
is
irrelevant.
There
is
no
reason
a
best
performer
for
one
HAP
should
be
a
best
performer
for
other
HAP.
Response:
EPA
agrees
with
this
comment.
On
reflection,
EPA
believes
that
because
all
our
standards
are
not
technically
interdependent
(
i.
e.,
implementation
of
one
emission
control
technology
does
not
prevent
the
source
from
implementing
another
control
technology),
the
fact
that
sources
are
not
achieving
all
the
standards
simultaneously
does
not
indicate
a
flaw
in
a
straight
emissions
approach.
See
Chemical
Manufacturers
Ass'n,
870
F.
2d
at
239
(
best
performing
sources
can
be
determined
on
a
pollutant­
by­
pollutant
basis
so
that
different
plants
can
be
best
performers
for
different
pollutants).
d.
Comment:
Several
commenters
took
the
opposite
position
that
EPA
must
assure
that
all
existing
source
standards
must
be
achievable
by
at
least
6
percent
of
the
sources,
and
that
all
new
source
standards
must
be
achievable
by
at
least
one
existing
source.
Response:
As
discussed
above,
we
are
not
obligated
to
establish
a
suite
of
floors
that
are
simultaneously
achievable
by
at
least
six
percent
of
the
sources
because
the
standards
are
not
technically
interdependent.
Nonetheless,
the
SRE/
Feed
methodology
does
result
in
existing
floor
levels
(
when
combined
with
the
other
floor
levels
for
sources
in
the
source
category)
that
are
simultaneously
achievable
by
at
least
six
percent
of
the
sources
(
or,
for
source
categories
that
have
fewer
than
30
sources,
by
at
least
two
or
three
sources).
90
However,
for
the
new
source
standards,
three
of
the
source
categories
do
not
include
any
sources
that
are
simultaneously
achieving
all
the
standards
(
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns).
Again,
similar
to
existing
sources,
EPA
is
not
obligated
to
establish
a
suite
of
new
source
floors
that
are
simultaneously
achievable
by
at
least
one
existing
source
because
these
standards
are
not
technically
interdependent.
We
conclude
that
a
new
source
can
be
designed
(
from
a
back­
end
control
perspective)
to
achieve
all
the
new
source
standards.
91
e.
Comment:
The
commenter
criticizes
EPA's
discussion
at
69
FR
21227­
228
indicating
that
both
hazardous
waste
feed
control
and
back­
end
pollution
control
are
superior
means
of
HAP
emission
control
and
treatment
standards
should
be
structured
to
allow
either
method
to
be
the
dominant
control
mechanism.
Response:
EPA
is
not
relying
on
this
part
of
the
proposed
preamble
discussion
as
justification
for
the
final
rule,
with
the
one
exception
noted
in
the
response
to
the
following
comment.

90
These
achievability
analyses
did
not
account
for
the
additional
test­
to­
test
variability
that
we
cannot
quantify.
91
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
V:
Emission
Estimates
and
Engineering
Costs,"
September
2005,
Section
4.2.3
for
a
discussion
that
explains
how
such
a
new
source
could
be
designed
to
achieve
the
new
source
standards.
f.
Comment:
Considerations
of
proper
waste
disposal
policy
are
not
relevant
to
MACT
floor
determinations.
In
any
case,
the
possibility
that
some
commercial
waste
combustors
may
upgrade
their
back­
end
pollution
control
systems
to
meet
standards
reflecting
low
hazardous
waste
HAP
feedrates,
or
divert
wastes
to
better­
controlled
units,
is
positive,
not
negative.
Response:
As
discussed
in
section
B.
1
above,
there
are
instances
where
standards
derived
by
using
a
straight
emissions
approach
are
based
on
a
combination
of
lowest
emitting
low
feeding
sources
and
lowest
emitting
higher
feeding
sources.
Resulting
floor
standards
would
thus
reflect
these
low
hazardous
waste
feedrates
and
could
put
some
well­
controlled
commercial
incinerators
in
the
untenable
situation
of
having
to
reduce
the
amount
of
hazardous
waste
that
is
treated
at
their
source.
Our
database
verifies
that
such
an
outcome
is
in
fact
realistic.
92
This
type
of
standard
would
operate
as
a
direct
constraint
on
the
amount
of
hazardous
waste
that
could
be
fed
to
the
device,
in
effect
depriving
a
combustion
source
of
its
raw
material.
In
this
instance,
hazardous
wastes
could
not
be
readily
diverted
to
other
units
because
the
low
feeding
hazardous
waste
sources
tend
not
to
be
commercial
units.
In
these
circumstances,
there
would
be
a
significant
adverse
nonair
environmental
impact.
Hazardous
waste
is
required
to
be
treated
by
Best
Demonstrated
Available
Technology
(
BDAT)
before
it
can
be
land
disposed.
RCRA
sections
3004
(
d),
(
e),
(
g),
and
(
m);
Hazardous
Waste
Treatment
Council
v.
EPA,
866
F.
2d
355,
361
(
D.
C.
Cir.
1990)
(
upholding
Best
Demonstrated
Available
Technology
treatment
requirement).
Most
treatment
standards
for
organic
pollutants
in
hazardous
waste
can
only
be
achieved
by
combustion.
Leaving
some
hazardous
wastes
without
a
treatment
option
is
in
derogation
of
these
statutory
requirements
and
goals,
and
calls
into
question
whether
a
treatment
standard
that
has
significant
adverse
nonair
environmental
impacts
must
be
viewed
as
best
performing.
See
Portland
Cement
Ass'n
v.
Ruckelshaus,
486
F.
2d
375
,
386
(
D.
C.
Cir.
1973);
Essex
Chemical
Co.
v.
EPA,
486
F.
2d
427,
439
(
D.
C.
Cir.
1973).
The
commenter's
statement
that
waste
disposal
policy
is
not
relevant
to
the
MACT
standard­
setting
process
is
not
completely
correct,
since
section
112
(
n)
(
7)
of
the
Clean
Air
Act
directs
some
accommodation
between
MACT
and
RCRA
standards
for
sources
combusting
hazardous
waste.
Part
of
this
accommodation
is
using
a
methodology
to
evaluate
best
performing
sources
that
evaluates
as
best
performers
those
using
the
best
combination
of
hazardous
waste
feed
control
(
among
other
things,
an
existing
control
measure
under
RCRA
rules)
and
system­
wide
removal.
We
assessed
whether
we
could
address
this
issue
by
subcategorizing
commercial
incinerators
and
on­
site
incinerators.
Applying
the
straight
emission
approach
to
such
a
subcategorization
scheme,
however,
yields
anomalous
results
due
to
the
scarcity
of
available
and
complete
compliance
test
data
from
commercial
incinerators.
Calculated
floor
levels
for
semivolatile
metals
and
low
volatile
metals
for
the
commercial
incinerator
subcategory
equate
to
2,023
and
111ug/
dscm,
respectively
(
both
higher
than
the
current
interim
standards).
93
We
conclude
that
the
SRE/
Feed
methodology
better
addresses
this
issue
92
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards",
September
2005,
Section
17.4.
93
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards",
September
2005,
Section
4.
and
Appendix
C,
Table
"
E­
INC­
SVM­
CT­
COM"
and
Table
"
E­
INC­
LVM­
CT­
COM"
because
it
yields
floor
levels
that
better
represent
the
performance
of
the
best
performing
commercial
incinerators
and
onsite
incinerators
alike
by
applying
equal
weights
to
hazardous
waste
feed
control
and
back­
end
control
in
the
ranking
process.
EPA
notes,
however,
that
its
choice
of
the
SRE/
Feed
methodology
is
justified
independent
of
considerations
of
adverse
impact
on
hazardous
waste
treatment
and
disposal.
Comment:
The
commenter
reiterates
its
comments
with
respect
to
floor
levels
for
new
sources.
Response:
EPA's
previous
responses
to
comments
apply
to
both
new
and
existing
source
standards.
Comment:
Two
commenters
recommend
that
EPA
define
the
single
best
performing
source
as
that
source
with
the
lowest
aggregated
SRE/
Feed
aggregated
score
(
as
proposed),
as
opposed
to
the
source
with
the
lowest
emissions
among
the
best
performing
existing
sources
(
an
approach
on
which
we
requested
comment).
Response:
We
agree
with
the
commenters
because
this
is
consistent
with
our
methodology
for
defining
best
performers
for
existing
sources
and
assessing
their
level
of
performance.
We
note,
however,
that
with
respect
to
the
new
source
standards,
we
encountered
two
instances
where
the
SRE/
Feed
methodology
identified
multiple
sources
with
identical
single
best
aggregated
scores,
resulting
in
a
tie
for
the
best
performing
source.
This
occurred
for
the
mercury
and
low
volatile
metal
new
source
standards
for
incinerators.
In
these
instances,
EPA
applied
a
tie
breaking
procedure
that
resulted
in
selecting
as
the
single
best
performing
source
as
that
source
(
of
the
tied
sources)
with
the
lowest
emissions.
We
believe
this
is
a
reasonable
interpretation
of
section112(
d)(
3),
which
states
the
new
source
standard
shall
not
be
less
stringent
than
the
emission
control
that
is
achieved
in
practice
by
the
best
controlled
similar
source
("
source"
being
singular,
not
plural).
Moreover,
we
believe
use
of
the
emission
level
as
the
tie­
breaking
criteria
is
reasonable,
not
only
because
it
is
a
measure
of
control,
but
because
we
have
already
fully
accounted
for
hazardous
waste
feedrate
control
and
system
removal
efficiency
in
the
ranking
methodology.
To
choose
either
of
these
factors
to
break
the
tie
would
give
that
factor
disproportionate
weight.

C.
Air
Pollution
Control
Technology
Methodologies
for
the
Particulate
Matter
Standard
and
for
the
Total
Chlorine
Standard
for
Hydrochloric
Acid
Production
Furnaces
At
proposal,
EPA
used
what
we
termed
`
air
pollution
control
technology'
methodologies
to
estimate
floor
levels
for
particulate
matter
from
all
source
categories
as
a
surrogate
for
non­
mercury
HAP
metals,
and
for
total
chlorine
from
hydrochloric
acid
furnace
production
furnaces.
69
FR
at
21225­
226.
Under
this
approach,
we
do
not
estimate
emission
reductions
attributable
to
feed
control,
but
instead
assess
the
performance
of
back­
end
control
technologies.
94
We
are
adopting
the
same
methodologies
for
these
HAP
in
the
final
rule.
Because
the
details
of
the
approaches
differ
for
particulate
matter
and
for
total
chlorine,
we
discuss
the
approaches
separately
below.
1.
Air
Pollution
Control
Device
Methodology
for
Particulate
Matter
Our
approach
to
establishing
floor
standards
for
particulate
matter
raises
three
major
issues.

94
See
generally
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards",
September
2005,
Section
7.4
and
7.5.
The
first
issue
is
whether
particulate
matter
is
an
appropriate
surrogate
for
nonenumerated
HAP
metals
from
all
inputs,
and
for
all
non­
mercury
HAP
metals
in
raw
material
and
fossil
fuel
inputs.
This
issue
is
discussed
at
section
IV.
A
of
this
part,
where
we
conclude
that
particulate
matter
is
indeed
a
reasonable
surrogate
for
these
metal
HAP.
The
second
issue
is
why
EPA
is
not
evaluating
some
type
of
feed
control
for
the
particulate
matter
floor.
There
are
two
potential
types
of
feed
control
at
issue:
hazardous
waste
feed
control
of
nonenumerated
metals,
and
feed
control
of
non­
mercury
HAP
metals
in
raw
material
and
fossil
fuel
inputs.
With
respect
to
feed
control
of
non­
enumerated
metals
in
hazardous
waste,
as
discussed
in
more
detail
in
section
IV.
A
of
this
part,
we
lack
sufficient
reliable
data
on
non­
enumerated
metals
to
assess
their
feedrates
in
hazardous
waste.
In
addition,
there
are
significant
questions
about
whether
feedrates
of
the
non­
enumerated
metals
can
be
optimized
along
with
SVM
and
LVM
feedrates.
We
also
have
explained
elsewhere
why
control
of
hazardous
waste
ash
feedrate
would
be
technically
inappropriate,
since
it
would
not
properly
assess
feed
control
of
nonenumerated
metals
in
hazardous
waste.
See
also
69
FR
at
21225.
We
have
also
explained
why
we
are
not
evaluating
control
of
feedrates
of
HAP
metals
in
raw
materials
and
fossil
fuels
to
hazardous
waste
combusters:
it
is
an
infeasible
means
of
control.
See
section
B
of
this
part.
We
consequently
are
not
evaluating
raw
material
and
fossil
fuel
ash
feed
control
in
determining
the
level
of
the
various
floors
for
particulate
matter.
a.
The
methodology
The
final
issue
is
the
means
by
which
EPA
is
evaluating
backend
control.
Essentially,
after
determining
(
as
just
explained)
that
back­
end
control
is
the
means
of
controlling
non­
mercury
metal
HAP
and
that
particulate
matter
is
a
proper
surrogate
for
these
metals,
EPA
is
using
its
engineering
judgment
to
determine
what
the
best
type
of
air
pollution
control
device
(
i.
e.,
back­
end
control)
is
to
control
particulate
matter
(
and,
of
course,
the
contained
HAP
metals).
We
then
ascertain
the
level
of
performance
by
taking
the
average
of
the
requisite
number
of
sources
(
either
12
%
or
five,
depending
on
the
size
of
the
source
category)
equipped
with
the
best
back­
end
control
with
the
lowest
emissions.
95
These
floor
standards
are
therefore
essentially
established
using
a
straight
emissions
methodology.
We
have
determined
that
baghouses
(
also
termed
fabric
filters)
are
generally
the
best
air
pollution
control
technology
for
control
of
particulate
matter,
and
that
electrostatic
precipitators
are
the
next
best.
b.
Why
not
select
the
lowest
emitters?
Although
sources
with
baghouses
tended
to
have
the
lowest
emission
levels
for
particulate
matter,
this
was
not
invariably
the
case.
There
are
certain
instances
when
sources
controlled
with
electrostatic
precipitators
(
or,
in
one
instance,
a
venturi
scrubber)
had
lower
emissions
in
individual
test
conditions
than
sources
we
identified
as
best
performing
which
were
equipped
with
baghouses.
96
Under
the
commenter's
approach,
we
must
always
use
these
lowest
emitting
sources
as
the
best
performers.
We
again
disagree.
We
do
not
know
if
these
sources
equipped
with
control
devices
other
than
baghouses
with
lower
emissions
in
single
test
conditions
would
actually
have
95
As
explained
in
the
responses
below,
the
approach
varies
slightly
if
the
requisite
number
of
sources
do
not
all
use
the
best
back­
end
pollution
control
technology.
In
that
case,
EPA
includes
in
its
pool
of
best
performers
the
lowest
emission
levels
from
sources
using
the
next
best
pollution
control
technology.
96
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
22.
lower
emissions
over
time
than
sources
equipped
with
baghouses
because
we
cannot
assess
their
uncontrollable
emissions
variability
over
time.
Our
data
suggests
that
they
likely
are
not
better
performing
sources.
We
further
conclude
that
our
statistical
procedures
that
account
for
these
sources'
within
test,
run­
to­
run
emissions
variability
underestimates
these
sources
long­
term
emissions
variability.
This
is
not
the
case
for
sources
equipped
with
baghouses,
where
we
have
completely
assessed,
quantified,
and
accounted
for
long­
term,
test­
to­
test
emissions
variability
through
application
of
the
universal
variability
factor.
97
The
sources
equipped
with
control
devices
other
than
baghouses
with
lower
snapshot
emissions
data
could
therefore
have
low
emissions
in
part
because
they
were
operating
at
the
low
end
of
the
`
uncontrollable'
emissions
variability
profile
for
that
particular
snapshot
in
time.
The
basis
for
these
conclusions,
all
of
which
are
supported
by
our
data,
are
found
in
section
16
of
volume
III
of
the
technical
support
document.
We
therefore
conclude
sources
equipped
with
baghouses
are
the
best
performers
for
particulate
matter
control
not
only
based
on
engineering
judgment,
but
because
we
are
able
to
reliably
quantify
their
likely
performance
over
time.
The
straight
emissions
methodology
ignores
the
presence
of
long­
term
emissions
variability
from
sources
not
equipped
with
baghouses,
and
assumes
without
basis
that
these
sources
are
always
better
performing
sources
in
instances
where
they
achieved
lower
snapshot
emissions
relative
to
the
emissions
from
baghouses,
emissions
that
have
notably
already
been
adjusted
to
account
for
long­
term
emissions
variability.
A
straight
emissions
approach
also
results
in
inappropriate
floor
levels
for
particulate
matter
because
it
improperly
reflects/
includes
low
ash
feed
when
identifying
best
performing
sources
for
particulate
matter.
69
FR
at
21228.
For
example,
the
MACT
pool
of
best
performing
liquid
fuel
boilers
for
particulate
matter
under
the
straight
emissions
approach
includes
eight
sources,
only
one
of
which
is
equipped
with
a
back­
end
control
device.
These
sources
have
low
particulate
matter
emissions
solely
because
they
feed
low
levels
of
ash.
The
average
ash
inlet
loadings
for
these
sources
are
well
over
two
orders
of
magnitude
lower
than
the
average
ash
inlet
loading
for
the
best
performing
sources
that
we
identify
with
the
Air
Pollution
Control
Technology
approach.
(
Of
course,
since
ash
loadings
are
not
a
proper
surrogate
for
HAP
metals,
these
sources'
emissions
are
lowest
for
particulate
matter
but
not
necessarily
for
HAP
metals.)
The
straight
emissions
approach
would
yield
a
particulate
matter
floor
level
of
0.0025
gr/
dscf
(
with
a
corresponding
design
level
of
0.0015
gr/
dscf).
There
is
not
one
liquid
fuel
boiler
that
is
equipped
with
a
back­
end
control
that
achieved
this
floor
level,
much
less
the
design
level.
The
best
performing
source
under
the
air
pollution
control
technology
approach,
which
is
equipped
with
both
a
fabric
filter
and
HEPA
filter,
did
not
even
make
the
pool
of
best
performing
sources
for
the
straight
emissions
approach.
Yet
this
unit
has
an
excellent
ash
removal
efficiency
of
99.8%
and
the
lower
emitting
devices'
removal
efficiencies
are,
for
the
most
part,
0%
because
they
do
not
have
any
back­
end
controls.
EPA
believes
that
it
is
arbitrary
to
say
that
these
essentially
uncontrolled
devices
must
be
regarded
as
"
best
performing"
for
purposes
of
section
112
(
d)
(
3).
We
therefore
conclude
that
a
straight
emissions
floor
would
not
be
achievable
for
any
source
feeding
appreciable
levels
of
ash,
even
if
they
all
were
to
upgrade
with
baghouses,
or
baghouses
in
combination
with
HEPA
filters,
and
that
a
rote
selection
of
lowest
emitters
as
best
performers
can
lead
to
the
nonsensical
result
of
uncontrolled
units
being
classified
as
best
performers.

97
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
5.3.
Comment:
Commenter
claims
end­
of­
stack
control
technology
is
not
the
only
factor
affecting
emissions
of
particulate
matter,
stating
that
EPA
admits
that
particulate
matter
emission
levels
are
affected
by
the
feedrate
of
ash.
Accordingly,
the
performance
of
a
source's
end­
of­
stack
control
technology
is
not
a
reasonable
estimate
of
that
source's
total
performance.
Response:
The
particulate
matter
standard
serves
as
a
surrogate
control
for
the
nonenumerated
metals
in
the
hazardous
waste
streams
(
for
all
source
categories),
and
all
nonmercury
metal
HAP
in
the
nonhazardous
waste
process
streams
(
essentially,
raw
materials
and
fossil
fuels)
for
cement
kilns,
lightweight
aggregate
kilns,
and
liquid
fuel
boilers.
The
commenter
suggests
that
the
APCD
approach
inappropriately
ignores
HAP
feed
control
in
the
assessment
of
best
performing
sources.
We
conclude
that
it
would
not
be
appropriate
to
use
a
methodology
that
directly
assesses
feed
control,
such
as
the
SRE/
Feed
methodology,
to
determine
particulate
matter
floors.
First,
direct
assessment
of
total
ash
feed
control
would
inappropriately
assess
and
seek
to
control
(
even
though
variability
of
raw
material
and
fossil
fuel
inputs
are
uncontrollable)
raw
material
and
fossil
fuel
HAP
input,
as
well
as
raw
material
and
fossil
fuel
input.
Controlling
raw
material
and
fossil
fuel
HAP
input
is
infeasible,
as
previously
discussed.
It
also
inappropriately
limits
theses
sources'
feedstocks
that
are
necessary
for
their
associated
production
process.
Second,
we
do
not
believe
that
developing
a
floor
standard
based
on
hazardous
waste
feed
control
of
nonenumerated
metals
(
as
opposed
to
feed
control
of
these
metals
in
raw
material
and
fossil
fuels)
is
appropriate
or
feasible.
In
part
four,
section
IV.
A,
we
explain
that
we
lack
the
data
to
reliably
assess
direct
feedrate
of
these
metals
in
hazardous
waste.
In
addition,
we
also
discuss
that
it
is
unclear
(
the
lack
of
certainty
resulting
from
the
sparse
available
data)
that
hazardous
waste
feed
control
of
the
nonenumerated
metals
is
feasible.
The
majority
of
these
metals
are
not
directly
regulated
under
existing
RCRA
requirements,
so
sources
have
optimized
control
of
the
other
HAP
metals,
raising
issues
of
whether
simultaneous
optimization
of
feed
control
of
the
remaining
metals
is
feasible.
Moreover,
even
if
one
were
to
conclude
that
hazardous
waste
feed
control
is
feasible
for
the
nonenumerated
metal
HAPs,
hazardous
waste
ash
feedrates
are
not
reliable
indicators
of
nonmercury
metal
HAP
feed
control
levels
and
are
therefore
inappropriate
parameters
to
assess
in
the
MACT
evaluation
process.
For
example,
a
source
could
reduce
its
ash
feed
input
by
reducing
the
amount
of
silica
in
its
feedstreams.
This
would
not
result
in
feed
control
or
emission
reductions
of
metal
HAP.
98
Finally,
hazardous
waste
ash
feed
control
levels
do
not
significantly
affect
particulate
matter
emissions
from
cement
kilns,
lightweight
aggregate
kilns,
and
solid
fuel­
fired
boilers
because
the
majority
of
particulate
matter
that
is
emitted
originates
from
the
raw
material
and
nonhazardous
fuel.
Hazardous
waste
ash
feed
control
levels
also
do
not
significantly
affect
particulate
matter
emissions
from
sources
equipped
with
baghouses
because
these
control
devices
are
not
sensitive
to
particulate
matter
inlet
loadings.
99
98
For
the
same
reason,
even
if
feed
control
of
total
inputs
(
i.
e.
raw
material
and
fossil
fuel
as
well
as
hazardous
waste
fuel)
were
feasible,
it
would
be
technically
inappropriate
to
use
ash
feedrates
as
a
surrogate:
ash
feed
control
allows
sources
to
selectively
reduce
the
ash
feeds
without
reducing
the
metal
HAP
portion
of
that
feed.
Back­
end
control,
in
contrast,
unselectively
removes
a
percentage
of
everything
that
is
fed
to
the
combustor.
99
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
3.1.
Thus,
even
if
one
were
to
conclude
that
the
nonenumerated
metal
HAPs
are
amenable
to
hazardous
waste
feed
control,
explicit
use
of
ash
feed
control
in
a
MACT
methodology
would
not
assure
that
each
source's
ability
to
control
either
nonmercury
metal
HAP
or
surrogate
particulate
matter
emissions
is
assessed.
The
Air
Pollution
Control
Device
methodology
identifies
and
assesses
(
with
the
surrogate
particulate
matter
standard)
the
known
technology
that
always
assures
metal
HAP
emissions
are
being
controlled
to
MACT
levels
 
that
technology
being
back­
end
control.
Comment:
Commenter
claims
the
Air
Pollution
Control
Device
approach
to
calculate
particulate
matter
floors
is
flawed
because
the
performance
of
back­
end
control
technology
alone
does
not
reflect
the
performance
of
the
relevant
best
sources
that
otherwise
would
be
reflected
if
EPA
were
to
assess
performance
based
on
the
emission
levels
each
source
achieved
because,
as
EPA
admits,
it
fails
to
account
for
the
effect
of
ash
feed
rate.
Response:
We
explain
above
why
the
Air
Pollution
Control
Technology
approach
properly
identifies
the
relevant
best
performing
sources
for
purposes
of
controlling
nonmercury
metal
HAP
(
measured
as
particulate
matter),
irrespective
of
ash
feed
rates.
Typically,
this
results
in
selecting
the
sources
with
the
lowest
particulate
matter
emission
rates,
the
result
the
commenter
advocates.
This
is
because
we
evaluate
sources
with
the
bestperforming
(
e.
g.
lowest
emitting)
baghouses,
and
particulate
matter
emissions
from
baghouses
are
not
significantly
affected
by
inlet
particulate
matter
loadings.
Where
the
pool
of
best
performing
sources
includes
sources
operating
some
other
type
of
back­
end
control
device
(
because
insufficient
numbers
of
sources
are
equipped
with
baghouses
to
comprise
12
%
of
sources,
or
five
sources
(
depending
on
the
size
of
the
source
category)),
we
again
use
the
lowest
particulate
matter
emission
level
from
the
sources
equipped
with
second
best
technology.
Although
these
data
do
not
reflect
test­
to­
test
variability,
they
are
the
best
remaining
data
in
EPA's
possession
to
estimate
performance
and
EPA
is
therefore,
as
required
by
section
112
(
d)
(
3)
(
A)
and
(
B),
using
the
data
to
fill
out
the
requisite
percentage
of
sources
for
calculating
floors.
Comment:
Commenter
states
that
EPA
has
failed
to
demonstrate
how
it
reasonably
estimated
the
actual
performance
of
each
source's
end­
of­
stack
control
technology
because:
1)
it
failed
to
acknowledge
that
there
can
be
substantial
differences
between
the
performance
of
different
models
of
the
same
type
of
technology;
and
2)
it
did
not
explain
or
support
its
rankings
of
pollution
control
devices.
Response:
As
discussed
in
sections
7.4
and
16.2
of
volume
III
of
the
technical
support
document
and
C.
1
of
this
comment
response
section,
we
rank
associated
back­
end
air
pollution
control
device
classes
(
e.
g.,
baghouses,
electrostatic
precipitators,
etc.),
after
assessing
particulate
matter
control
efficiencies
from
hazardous
waste
combustors
that
are
equipped
with
the
associated
back­
end
control
class.
The
data
used
to
make
this
assessment
are
included
in
our
database.
We
also
evaluated
particulate
matter
control
efficiencies
from
other
similar
source
categories
that
also
use
these
types
of
control
systems,
such
as
municipal
waste
combustors,
medical
waste
incinerators,
sewage
sludge
combustors,
coal­
fired
boilers,
oil
fired
boilers,
non­
hazardous
industrial
waste
combustors,
and
non­
hazardous
waste
Portland
cement
kilns.
100
After
we
assign
a
ranking
score
to
each
back­
end
control
class,
we
determine
the
number
of
sources
that
are
using
each
of
these
control
technology
classes.
We
then
identify
100
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
5.3
and
16.2,
for
further
discussion.
the
MACT
control
technology
or
technologies
to
be
those
best
ranked
back­
end
controls
that
are
being
used
by
12
percent
of
the
sources
(
or
used
by
five
sources
in
instances
where
there
are
fewer
than
30
sources).
We
then
look
only
at
those
sources
using
MACT
back­
end
control
and
rank
order
all
these
sources
first
by
back­
end
control
type,
and
second
by
emissions.
For
example,
in
instances
where
there
is
more
than
one
MACT
back­
end
control,
we
array
the
emissions
from
the
sources
equipped
with
the
top
ranked
back­
end
controls
from
best
to
worst
(
i.
e.,
lowest
to
highest),
followed
by
the
emissions
from
sources
equipped
with
the
second
ranked
back­
end
controls
from
best
to
worst,
and
so
on.
We
then
determine
the
appropriate
number
of
sources
to
represent
12
percent
of
the
source
category
(
5
in
instances
where
there
are
fewer
than
30
sources).
If
10
sources
represented
12%
of
the
sources
in
the
source
category,
we
would
then
select
the
emissions
from
best
ranked
10
sources
in
accordance
with
this
ranking
procedure
to
calculate
the
MACT
floor.
This
methodology
results
in
selection
of
lowest
emitters
using
best
back­
end
air
pollution
control
as
pool
of
the
best
performing
sources.
The
commenter
is
correct
that
there
can
be
differences
between
the
performance
of
different
models
of
the
same
type
of
technology.
We
are
not
capable
of
thoroughly
assessing
differences
in
designs
of
each
air
pollution
control
device
in
a
manner
that
could
be
used
in
the
MACT
evaluation
process,
so
that
we
would
only
select,
for
example,
baghouses
of
a
certain
type.
Each
baghouse,
for
example,
will
be
designed
differently
and
thus
will
have
different
combinations
of
design
aspects
that
may
or
may
not
make
that
baghouse
better
than
other
baghouses
(
e.
g.,
bag
types,
air
to
cloth
ratios,
control
mechanisms
to
collect
accumulated
filter
cake
and
maintain
optimum
pressure
drops).
We
also
do
not
have
detailed
design
information
for
each
source's
air
pollution
control
system;
such
an
assessment
would
therefore
not
be
possible
even
if
the
information
could
be
used
to
assess
relative
performance.
We
instead
account
for
this
difference
by
selecting
sources
with
the
lowest
emissions
that
are
using
the
defined
MACT
back­
end
controls
to
differentiate
the
performance
among
those
sources
that
are
using
that
technology
(
the
best
performer
being
the
source
with
the
lowest
emissions,
as
just
explained).
For
example,
in
situations
where
more
than
12%
of
the
sources
are
using
the
single
best
control
technology
(
e.
g.,
more
than
12%
of
incinerators
use
baghouses
to
control
particulate
matter),
we
use
the
emissions
from
the
lowest
emitting
sources
equipped
with
baghouses
to
calculate
the
MACT
floor.
In
instances
where
there
are
two
defined
MACT
technologies
(
i.
e.,
12%
of
sources
do
not
use
the
single
best
control
technology),
we
use
all
the
emissions
data
from
sources
equipped
with
the
best
ranked
control
class,
and
then
subsequently
use
only
the
lowest
emissions
from
the
sources
equipped
with
the
second
ranked
back­
end
controls.
Comment:
EPA
did
not
say
how
it
picked
the
best
performers
if
more
than
twelve
percent
used
the
chosen
technologies.
If
EPA
used
emissions
data
to
differentiate
performance,
the
Agency
is
necessarily
acknowledging
that
emissions
data
are
a
valid
measure
of
sources'
performance
­
in
which
case
the
Agency's
claims
to
the
contrary
are
arbitrary
and
capricious.
Response:
We
did
use
emissions
data
to
select
the
pool
of
best
performers
where
over
12%
use
the
best
type
of
emissions
control
technology,
as
explained
in
the
previous
response.
Emissions
data
is
obviously
one
means
of
measuring
performance.
EPA's
position
is
that
it
need
not
be
the
exclusive
means,
in
part
because
doing
so
leads
to
arbitrary
results
in
certain
situations.
Our
use
of
emission
levels
to
rank
sources
that
use
the
best
particulate
matter
control
(
i.
e.,
baghouses)
does
not
lead
to
arbitrary
results,
however.
First,
we
are
assessing
emission
levels
here
as
a
means
of
differentiating
sources
using
a
known
type
of
pollution
control
technology.
More
importantly,
the
adjusted
emission
levels
from
sources
equipped
with
baghouses
are
the
most
accurate
measures
of
performance
because
these
emissions
have
been
statistically
adjusted
to
accurately
account
for
long­
term
variability
through
application
of
the
universal
variability
factor.
Comment:
Commenter
states
that
EPA,
in
its
support
for
its
Air
Pollution
Control
Technology
Approach
used
to
calculate
particulate
matter
floors,
claims
that
an
emissionsbased
approach
would
result
in
floor
levels
that
"
could
not
necessarily
be
achieved
by
sources
using
the
chosen
end­
of­
stack
technology,"
citing
69
FR
at
21228.
Commenter
claims
that
it
is
settled
law
that
standards
do
not
have
to
be
achievable
through
the
use
of
any
given
control
technology,
and
that
it
is
also
erroneous
to
establish
floors
at
levels
thought
to
be
achievable
rather
than
levels
sources
actually
achieve.
Response:
EPA
is
not
establishing
floor
levels
based
on
assuring
the
standards
are
achievable
by
a
particular
type
of
end­
of­
stack
technology
(
or,
for
that
matter,
any
end­
ofstack
technology).
The
floor
levels
in
today's
final
rule
reasonably
estimate
average
performance
of
the
requisite
percent
of
best
performing
sources
without
regard
for
whether
the
levels
themselves
can
be
achieved
by
a
particular
means.
Floor
standards
for
particulate
matter
are
based
on
the
performance
of
those
sources
with
the
lowest
emissions
using
the
best
back­
end
control
technology
(
most
often
baghouses,
and
sometimes
electrostatic
precipitators).
EPA
uses
this
approach
not
to
assure
that
the
floors
are
achievable
by
sources
using
these
control
devices,
but
to
best
estimate
performance
of
the
best
performing
sources,
including
these
sources'
variability.
2.
Total
Chlorine
Standard
for
Hydrochloric
Acid
Production
Furnaces
We
are
adopting
the
methodology
we
proposed
to
estimate
floor
levels
for
total
chlorine
from
hydrochloric
acid
production
furnaces.
69
FR
at
21225­
226.
As
stated
there,
we
are
defining
best
performers
as
those
sources
with
the
best
total
chlorine
system
removal
efficiency.
We
are
not
assessing
a
level
of
control
attributable
to
control
of
chlorine
in
feedstocks
because
this
would
simply
prevent
these
furnaces
from
producing
their
ultimate
product.
Further
details
are
presented
in
responses
below.
Comment:
Basing
the
standard
for
hydrochloric
acid
production
furnaces
on
the
basis
of
system
removal
efficiency
rather
than
chlorine
emission
reduction
is
impermissible.
Even
though
these
devices'
purpose
is
to
produce
chlorinated
product,
the
furnaces
can
use
less
chlorinated
inputs.
EPA's
proposed
approach
is
surreptitious,
an
impermissible
attempt
to
assure
that
the
standards
are
achievable
by
all
sources
using
EPA's
chosen
technology,
the
approach
already
rejected
in
CKRC.
Response:
EPA
disagrees.
There
is
nothing
in
the
text
of
the
statute
that
compels
an
approach
that
forces
sources
to
produce
less
product
to
achieve
a
MACT
floor
standard.
Yet
this
is
the
consequence
of
the
comment.
If
standards
were
based
on
levels
of
chlorine
in
feedstock
to
these
units,
less
product
would
be
produced
since
there
would
be
less
chlorine
to
recover.
EPA
has
instead
reasonably
chosen
to
evaluate
best
performing/
best
controlled
sources
for
this
source
category
by
measuring
the
efficiency
of
the
entire
chlorine
emission
reduction
system.
Indeed,
the
situation
here
is
similar
to
that
in
Mossville,
where
polyvinyl
chloride
production
units
fed
raw
materials
containing
varying
amounts
of
vinyl
chloride
depending
on
the
product
being
produced.
This
led
to
variable
levels
of
vinyl
chloride
in
plant
emissions.
Rather
than
holding
that
EPA
must
base
a
floor
standard
reflecting
the
lowest
amount
of
vinyl
chloride
being
fed
to
these
units,
the
court
upheld
a
standard
estimating
the
amount
of
pollution
control
achievable
with
back­
end
control.
370
F.
3d
at
1240,
1243.
In
the
present
case,
as
in
Mossville,
the
standard
is
based
on
actual
performance
of
back­
end
pollution
control
(
although
here
EPA
is
assessing
actual
performance
of
the
control
technology
rather
than
estimating
performance
by
use
of
a
regulatory
limit,
making
the
situation
here
a
fortiorari
from
that
in
Mossville),
and
does
not
reflect
"
emission
variations
not
related
to
technological
performance".
370
F.
3d
at
1240.
It
also
should
be
evident
that
EPA
is
not
establishing
a
standard
to
assure
its
achievability
by
a
type
of
pollution
control
technology,
as
the
commenter
mistakenly
asserts.
The
standard
for
total
chlorine
is
based
on
the
average
of
the
best
five
sources
 
best
meaning
those
sources
with
greatest
(
most
efficient)
system
removal
efficiencies.
EPA
did
not,
as
in
CKRC,
establish
the
standard
using
the
highest
emission
limit
achieved
by
a
source
operating
a
particular
type
of
control.
Comment:
The
commenter
generally
maintains
that
EPA's
methodology
to
determine
total
chlorine
floors
for
hydrochloric
acid
production
furnaces
fails
to
capture
other
means
of
HAP
emission
control
that
otherwise
would
be
captured
if
EPA
were
assess
performance
based
on
the
emission
levels
each
source
achieved.
Response:
As
discussed
above,
the
standard
for
total
chlorine
is
based
on
the
sources
with
the
best
system
removal
efficiencies.
System
removal
efficiency
encompasses
all
means
of
MACT
floor
control
when
assessing
relative
performance
because:
1)
chlorine
feed
control
is
not
a
MACT
floor
technology
for
these
sources;
and
2)
the
measure
of
system
removal
efficiency
accounts
for
every
other
controllable
factor
that
can
affect
emissions
(
e.
g.,
operating
practices,
worker
training,
proper
maintenance,
pollution
control
device
type,
etc).

D.
Format
of
Standards
1.
Thermal
Emissions
EPA
proposed,
and
is
finalizing
standards
for
HAP
metals
and
chlorine
(
the
HAPs
amenable
to
hazardous
waste
feed
control)
emitted
by
energy
recovery
units
(
cement
kilns,
lightweight
aggregate
kilns,
and
liquid
fuel
boilers)
expressed
in
terms
of
pounds
of
HAP
attributable
to
the
hazardous
waste
fuel
per
million
british
thermal
units
(
BTUs)
of
hazardous
waste
fired.
69
FR
at
21219­
20.
EPA
received
many
comments
on
this
issue
to
which
we
respond
below
and
in
the
Response
to
Comment
Document.
Some
initial
discussion
of
the
issue
is
appropriate,
however.
a.
Expressing
Standards
in
Terms
of
a
Normalizing
Parameter
is
Reasonable.
First,
using
a
thermal
emissions
form
of
a
standard
is
an
example
of
expressing
standards
in
terms
of
a
normalizing
parameter.
EPA
routinely
normalizes
emission
standards
either
by
expressing
them
as
stack
HAP
concentrations
or
by
expressing
the
standards
in
units
of
allowable
mass
emissions
per
amount
of
production
or
raw
material
processed.
Emission
concentration­
based
standards
normalize
the
size
of
each
source
by
accounting
for
volumetric
gas
flowrate,
which
is
directly
tied
to
the
amount
of
raw
material
each
source
processes
(
and
subsequently
the
amount
of
product
that
is
produced).
Metal
and
particulate
matter
emission
standards
for
commercial
and
industrial
solid
waste
incinerators
are
expressed
in
emission
concentration
format.
See
§
60.2105.
The
particulate
matter
standard
for
Portland
cement
kilns
is
expressed
as
mass
of
allowable
emissions
per
mass
of
raw
material
processed.
See
§
63.1342.
The
particulate
matter,
mercury,
and
hydrogen
chloride
standards
for
nonhazardous
waste
industrial
boilers
are
expressed
as
pounds
of
allowable
emissions
per
million
British
thermal
units
(
BTUs).
§
See
63.7500.
Technology­
based
standards
typically
normalize
emissions
because
such
a
format
assures
equal
levels
of
control
across
sources
per
amount
of
raw
material
that
is
processed,
and
allows
EPA
to
equally
assess
source
categories
that
comprise
units
that
differ
in
size.
By
normalizing
the
emissions
standard
we
better
ensure
the
same
percentage
of
emission
reduction
per
unit
of
raw
material
processed
by
each
source.
101
See
Weyerhaeuser
v.
Costle,
590
F.
2d
1011,
1059
(
D.
C.
Cir.
1978)
(
technology­
based
standards
are
typically
expressed
in
terms
of
volume
of
pollutants
emitted
per
volume
of
some
type
of
unit
of
production).
There
is
no
legal
bar
to
this
approach
since
the
statute
does
not
directly
address
the
question
of
whether
a
source
emitting
100
units
of
HAP
per
unit
of
production
but
100
units
of
HAP
overall
is
a
better
performer
(
or,
for
new
sources,
better
controlled)
than
a
source
emitting
10
units
of
HAP
per
unit
of
production
but
emitting
101
units
overall.
102
One
commenter
appeared
to
suggest
that
we
should
assess
performance
on
mass
feedrates
and
mass
emission
rates,
without
normalizing.
Such
an
approach
would
yield
nonsensical
results
because
the
best
performing
sources
would
more
likely
be
the
smallest
sources
in
the
source
category
(
smaller
sources
generally
have
lower
mass
emission
rates
because
they
process
less
hazardous
waste).
This
would
likely
yield
emission
standards
that
would
not
be
achievable
by
the
larger
sources
that
more
likely
are
better
controlled
sources
based
on
a
HAP
removal
efficiency
basis.
103
Normalization
by
unit
of
production
is
another
way
of
expressing
unit
size,
so
that
normalizing
on
this
basis
is
a
reasonable
alternative
to
subcategorization
on
a
plant
size­
by­
plant
size
basis.
See
section
112
(
d)
(
1)
(
size
is
an
enumerated
basis
for
subcategorizing).
b.
Using
Hazardous
Waste
Thermal
Input
as
the
Normalizing
Parameter
is
Permissible
and
Reasonable.
Normalization
of
standards
based
on
thermal
input
is
analogous.
For
energy
recovery
units
(
in
this
rule,
kilns
and
most
liquid
fuel
boilers),
normalizing
on
the
basis
of
thermal
input
uses
a
key
feed
input
as
the
normalizing
parameter,
allowing
comparison
of
units
with
different
inputs
rather
than
separately
evaluating
these
units
by
size
and
type
(
see
section
112
(
d)
(
1)).
Again,
this
approach
is
legally
permissible.
The
statute
does
not
answer
the
question
of
which
source
is
better
performing,
the
source
emitting
100
pounds
of
HAP
per
million
BTUs
hazardous
waste
but
100
pounds
of
HAP
overall
or
the
source
emitting
10
pounds
of
HAP
per
million
BTUs
hazardous
waste
but
emitting
101
pounds
overall.
The
approach
also
is
reasonable.
First,
as
with
other
standards
expressed
in
normalized
terms,
by
normalizing
the
emissions
standard
we
ensure
the
same
percentage
of
emission
reduction
per
unit
of
raw
material
processed
by
each
source,
thus
allowing
meaningful
comparison
among
sources.
For
example,
emission
concentration­
based
standards
normalize
the
size
of
each
source
by
accounting
for
volumetric
gas
flowrate,
which
is
directly
tied
to
the
amount
of
raw
material
each
source
processes
(
and
subsequently
to
the
101
A
more
familiar
example
of
normalization
is
the
Earned
Run
Average
(
ERA),
which
normalizes
a
baseball
pitchers'
earned
runs
on
the
basis
of
nine
innings
pitched
in
order
to
make
comparisons
among
pitchers
possible.
102
Or,
put
another
way,
the
statute
does
not
directly
address
the
question
of
whether
a
small
source
that
emits
10
units
of
HAP
is
better
than
a
much
larger
source
with
better
back­
end
control
(
but
feeding
the
same
raw
material
at
a
higher
mass
feedrates)
that
emits
100
units
of
HAP.
103
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
6.0.
amount
of
product
that
is
produced),
and
assures
equal
levels
of
control
per
amount
of
product.
Normalization
on
the
basis
of
HAP
amount
in
hazardous
waste
per
BTU
level
in
the
hazardous
waste
similarly
assures
equal
levels
of
control
across
sources
per
amount
of
raw
material
that
is
processed.
Here,
the
raw
material
is
the
hazardous
waste
fuel,
expressed
as
units
of
energy.
It
is
reasonable
to
regard
a
hazardous
waste
fuel
as
a
raw
material
to
an
energy
recovery
device.
Indeed,
fuels
are
the
only
input
to
boilers,
so
fuels
are
necessarily
such
units'
sole
raw
material.
104,
105
Hazardous
waste
burning
cement
kilns
and
lightweight
aggregate
kilns
produce
a
product
in
addition
to
recovered
energy
and
so
process
other
raw
materials.
However,
the
reason
these
units
use
hazardous
waste
as
inputs
is
typically
to
recover
usable
energy
from
the
wastes.
Hence,
the
hazardous
waste
fuel
is
reasonably
viewed
as
a
raw
material
to
these
devices.
In
this
regard,
we
note
that
our
choice
of
normalizing
parameter
essentially
says
that
best
performers
with
respect
to
hazardous
waste
fuel
burned
in
energy
recovery
units
are
those
using
the
lowest
HAP
feedrate
(
for
metals
and
chlorine)
per
amount
of
energy
recovered.
106
This
approach
accords
well
with
the
requirement
in
section
112
(
d)
(
2)
that
EPA
take
energy
considerations
into
account
in
developing
MACT,
and
also
that
the
Agency
consider
front­
end
means
of
control
such
as
input
substitution
(
section
112
(
d)
(
2)
(
A)).
In
addition,
our
choice
furthers
the
RCRA
goal
of
encouraging
properly
conducted
recycling
and
reuse
(
RCRA
section
1003
(
b)
(
6)),
which
is
of
relevance
here
in
that
Congress
directed
EPA
to
consider
the
RCRA
emission
controls
for
hazardous
waste
combustion
units
in
developing
MACT
standards
for
these
units,
and
to
ensure
"
to
the
maximum
extent
possible,
and
consistent
with
[
section
112
]"
that
section
112
standards
are
"
consistent"
with
the
RCRA
scheme.
CAA
section
112
(
n)
(
7).
107
Conversely,
emission
concentration­
based
standards,
the
methodology
that
otherwise
would
be
used
to
calculate
emission
concentration­
based
standards,
may
result
in
standards
that
are
biased
against
sources
that
recover
more
energy
from
hazardous
waste.
This
may
discourage
sources
from
recovering
energy
from
hazardous
waste
because
such
standards
do
not
normalize
each
source's
allowable
emissions
based
on
the
amount
of
hazardous
waste
it
processes
for
energy
recovery
purposes.
See
69
FR
at
21219
and
responses
below.
Second,
use
of
this
normalizing
parameter
makes
it
much
more
likely
that
hazardous
waste
feed
controls
will
be
utilized
by
these
devices
as
an
aspect
of
emissions
control.
See
104
EPA
thus
has
expressed
the
MACT
standards
for
particulate
matter,
mercury,
and
hydrogen
chloride
standards
for
nonhazardous
waste
industrial
boilers
as
pounds
of
allowable
emissions
per
million
BTUs.
§
See
63.7500.
This
normalization
considers
the
total
heat
input
into
the
combustion
device.
Normalizing
by
total
heat
input
would
not
be
appropriate
for
hazardous
waste
combustors
for
metals
and
chlorine
because
this
would
implicitly
account
for,
and
in
turn
require
the
use
of,
feed
control
of
HAP
in
non
hazardous
waste
fuels.
This
is
inappropriate
for
the
reasons
discussed
in
Section
III.
B
of
this
Part.
105
We
distinguish
(
i.
e.,
subcategorize)
liquid
fuel
boilers
that
process
hazardous
waste
with
heating
values
less
than
10,000
BTU/
lb
from
those
processing
hazardous
wastes
with
heating
content
greater
than
10,000
BTU/
lb.
Although
boilers
that
process
hazardous
waste
with
heating
values
less
than
10,000
BTU/
lb
are
still
considered
to
be
energy
recovery
units,
we
conclude
a
thermal
emissions
normalization
approach
for
these
sources
is
not
appropriate.
See
Part
Four,
Section
VI.
D.
106
As
explained
earlier,
the
ultimate
ranking
of
best
performers
then
further
evaluates
system
removal
efficiency,
best
performers
then
being
defined
in
terms
of
the
combination
of
hazardous
waste
thermal
feed
and
system
removal
efficiency.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards",
September
2005,
Section
7.3.
107
EPA
would
adopt
the
thermal
format
for
the
standards,
however,
whether
or
not
the
approach
furthered
RCRA
objectives.
section
112
(
d)
(
2)
(
A)
(
use
of
measures
reducing
the
volume
of
pollutants
emitted
through
"
substitution
of
materials");
CKRC,
255
F.
3d
at
865
(
EPA
to
consider
means
of
control
in
addition
to
back­
end
pollution
control
technology
when
establishing
MACT
floors).
As
explained
in
our
discussion
of
the
SRE/
Feed
methodology,
the
MACT
floor
level
for
metals
and
chlorine
reflects
the
best
combination
of
hazardous
waste
feedrate,
and
total
HAP
removal
efficiency.
See
section
III.
B.
However,
if
standards
for
energy
recovery
units
are
expressed
in
terms
of
mass
of
HAP
per
volume
of
stack
gas,
then
it
would
be
relatively
easy
for
these
energy
recovery
devices
to
achieve
a
standard,
without
decreasing
concentrations
of
HAP
in
their
hazardous
waste
fuels,
by
diluting
the
HAP
contribution
of
hazardous
waste
with
emissions
from
fossil
fuel.
A
thermal
emissions
format
prevents
this
type
of
dilution
from
happening
because
it
ignores
additions
of
stack
gases
attributable
to
burning
fossil
fuels.
Weyerhaeuser,
590
F.
2d
at
1059
(
use
of
production
of
a
unit
as
a
normalizing
parameter
serves
"
the
commendable
purpose"
of
preventing
plants
from
achieving
emission
limitations
via
dilution).
For
example,
assume
there
are
two
identical
energy
recovery
units
with
identical
back­
end
control
devices
(
that
reflect
the
performance
of
the
average
of
the
best
performing
sources).
Source
A
fulfills
25%
of
its
energy
demand
from
the
combustion
of
hazardous
waste;
source
B
fulfills
50%
of
its
energy
demand
from
the
combustion
of
hazardous
waste.
Also
assume
that
the
hazardous
waste
for
these
two
sources
have
equivalent
energy
contents.
If
these
sources
were
required
to
comply
with
an
emission
concentration
based­
standard
(
e.
g.,
ug/
dscm),
source
A
would
be
allowed
to
feed
hazardous
waste
containing
twice
the
metal
content
(
on
a
mass
concentration
basis,
e.
g.,
ppm),
and
would
be
allowed
to
emit
metal
HAP
at
the
same
mass
emission
rate
relative
to
source
B.
This
is
because
this
source
is
effectively
diluting
its
emissions
with
the
emissions
that
are
being
generated
by
the
fossil
fuels.
108
A
thermal
emissions
standard
format
does
not
allow
sources
to
dilute
their
emissions
with
the
emissions
from
fossil
fuel
inputs
because
it
directly
regulates
the
emissions
and
feeds
associated
with
the
hazardous
waste
fuel.
Under
a
thermal
emissions
format
both
sources
would
be
required
to
feed
hazardous
waste
with
the
same
thermal
feed
concentrations
(
on
a
lb
HAP
per
million
BTU
hazardous
waste
basis),
and
source
A
would
be
required
to
process
hazardous
waste
with
an
equivalent
concentration
of
metal
HAP
(
on
a
mass
basis)
and
also
be
required
to
emit
half
as
much
metal
HAP
(
on
a
mass
emission
rate
basis)
relative
to
source
B,
because
source
A
is
processing
half
as
much
hazardous
waste
fuel,
thus
vindicating
the
hazardous
waste
feed
control
aspect
of
the
standard
(
see
also
note
below
regarding
the
likelihood
of
sources
using
hazardous
waste
feed
control).
Further,
the
thermal
feed
concentration
with
which
these
sources
must
comply
reflects
the
feed
control
of
the
average
performance
of
the
best
performing
sources
(
on
a
mass
of
HAP
per
million
BTU
basis).
Such
a
requirement
assures
that
these
sources
are
processing
the
cleanest
hazardous
waste
fuels
to
recover
energy
and
are
reducing
HAP
emissions
to
MACT
levels.
We
note
that
it
would
not
be
appropriate
to
express
the
emission
standards
for
incinerators,
hydrochloric
acid
production
furnaces,
and
solid
fuel
boilers
in
terms
of
thermal
emissions.
As
just
explained,
the
choice
of
a
normalizing
parameter
is
fitted
to
the
nature
of
the
device
to
which
it
is
applied
in
order
to
allow
the
most
meaningful
comparisons
between
devices
of
like
type.
We
therefore
conclude
that
a
thermal
emissions
format
(
i.
e.,
normalizing
parameter)
for
incinerators
is
not
appropriate
because
the
primary
function
of
incinerators
is
to
thermally
treat
hazardous
waste
(
as
opposed
to
recovering
energy
from
the
108
This
example
assumes
there
are
no
HAP
emissions
attributable
to
the
fossil
fuels.
hazardous
waste).
See
67
FR
at
17362
(
April
19,
1996).
Our
database
indicates
that
most
incinerators
processed
hazardous
waste
during
their
emissions
tests
that
had,
on
average,
heating
values
below
10,000
BTU/
lb.
109
We
have
emission
test
hazardous
waste
heating
value
information
for
62
incinerators
in
our
database.
Of
these
62
sources,
40
sources
processed
hazardous
waste
with
an
average
heating
value
of
less
than
10,000
BTU/
lb.
The
other
22
sources
processed
hazardous
waste
with
heating
values
greater
than
10,000
BTU/
lb
in
at
least
one
test
condition,
although
we
note
that
14
of
these
22
sources
also
processed
hazardous
waste
in
different
test
conditions
with
heating
values
lower
than
10,000
BTU/
lb.
110
We
assessed
whether
we
should
subcategorize
incinerators,
similar
to
how
we
subcategorize
liquid
fuel
boilers,
based
on
the
BTU
content
of
the
hazardous
waste.
Incinerators
do
recover
energy
from
processing
high
BTU
wastes.
Some
incinerators
are
equipped
with
waste
heat
boilers,
and
high
BTU
hazardous
waste
can
displace
fossil
fuels
that
otherwise
would
have
to
be
burned
to
thermally
treat
low
BTU
wastestreams.
However,
such
energy
recovery
is
considered
to
be
a
secondary
product
because
their
primary
function
is
to
thermally
treat
hazardous
waste.
A
thermal
emissions
normalization
approach
for
incinerators
that
combust
hazardous
wastes
with
heating
values
greater
than
10,000
BTU/
lb
would
therefore
not
be
appropriate
because
the
normalized
parameter
would
not
be
tied
to
the
primary
production
output
that
results
from
the
processing
of
hazardous
waste
(
i.
e.,
treated
hazardous
waste).
In
confirmation,
no
commenters
suggested
that
we
apply
a
thermal
emissions
format
to
incinerators.
We
also
conclude
that
a
thermal
emission
format
is
inappropriate
for
hydrochloric
acid
production
furnaces.
These
devices
recover
chlorine,
an
essential
raw
material
in
the
process,
from
hazardous
waste.
The
classic
normalizing
parameter
of
amount
of
product
(
HCl)
produced
is
therefore
the
obvious
normalizing
parameter
for
these
sources.
It
is
true
that
some
hydrochloric
acid
production
furnaces
recover
energy
from
high
BTU
hazardous
wastes.
See
56
FR
at
7141/
1
and
7141­
42
(
Feb.
21,
1991).
Some
sources
are
equipped
with
waste
heat
boilers,
and
high
BTU
wastes
help
sustain
the
combustion
process,
which
is
necessary
to
liberate
the
chlorine
from
the
wastestreams
prior
to
recovering
the
chlorine
in
the
scrubbing
systems.
Again,
energy
recovery
is
not
the
primary
function
of
these
types
of
sources.
111
Hydrochloric
acid
production
furnace
hazardous
waste
heating
values
range
from
1,100
to11,000
BTU/
lb
(
the
median
energy
content
for
these
sources
is
slightly
above
6000
BTU/
lb).
The
range
of
hazardous
waste
heating
contents
from
these
sources
is
much
lower
109
As
discussed
later,
the
heating
values
of
hazardous
wastes
processed
at
cement
kiln
and
lightweight
aggregate
kilns
are
primarily
10,000
BTU/
lb
or
greater.
110
These
data
are
based
on
a
compilation
of
heating
contents
for
every
incinerator
test
condition
in
the
database
where
the
source
reported
such
heating
content,
and
include
both
the
most
recent
test
conditions
as
well
as
older
test
conditions.
Incinerator
test
condition
heating
values
range
from
a
low
of
790
to
a
high
of
19,800
BTU/
lb,
with
a
median
value
of
7800
BTU/
lb.
111
EPA
notes
that
when
first
adopting
RCRA
air
emission
standards
for
hydrochloric
acid
recovery
furnaces
(
then
called
`
halogen
acid
furnaces'),
EPA
indicated
that
those
furnaces
designed
as
boilers
would
be
subject
to
the
emission
standards
for
boilers.
56
FR
at
7040.
This
determination
did
not
have
regulatory
consequence,
since
all
hydrochloric
acid
production
furnaces
were
subject
to
the
same
emission
standards
whether
they
were
classified
as
boilers
or
as
industrial
furnaces.
Thus,
EPA
was
not
concluding
that
some
hydrochloric
acid
furnaces
existed
for
the
primary
purpose
of
recovering
energy
in
the
1991
rulemaking.
56
FR
at
7139
("[
Hydrochloric
acid
recovery
furnaces]
are
typically
modified
firetube
boilers
that
process
secondary
waste
streams
containing
20
to
70
per
cent
chlorine
or
bromine
to
produce
a
halogen
acid
product
by
scrubbing
acid
from
the
combustion
gases").
than
the
ranges
for
cement
kilns,
lightweight
aggregate
kilns,
and
liquid
fuel
boilers,
supporting
the
premise
that
energy
recovery
is
of
secondary
importance.
In
addition,
and
critically,
the
hazardous
waste
that
is
processed
in
these
units
contains
high
concentrations
of
chlorine,
confirming
that
the
wastes
serve
as
feedstock
for
hydrochloric
acid
production,
even
if
the
wastes
also
have
energy
value.
112
No
commenters
suggested
that
we
apply
a
thermal
emissions
format
to
hydrochloric
acid
production
furnaces.
We
consider
the
processing
of
hazardous
waste
in
solid
fuel
boilers
to
be
more
reflective
of
energy
recovery
(
relative
to
incinerators
and
hydrochloric
acid
production
furnaces)
because
these
sources
directly
recover
the
heat
that
is
released
from
the
combustion
of
the
waste
streams.
However,
as
stated
at
proposal,
not
all
these
sources
are
processing
hazardous
wastes
for
energy
recovery.
69
FR
at
21220.
These
boilers
are
generally
not
commercial
units,
and
so
tend
to
burn
whatever
hazardous
wastes
are
generated
at
the
facility
where
they
are
located.
Heating
values
for
this
source
category
range
from
1,300
to
10,500
BTU/
lb,
with
a
median
value
of
8000
BTU/
lb.
We
therefore
conclude
that
thermal
emission
standards
for
these
sources
are
not
appropriate
because
most
of
these
sources
are
processing
hazardous
waste
with
energy
content
lower
than
10,000
BTU/
lb.
As
discussed
in
section
VI.
D,
we
conclude
that
10,000
BTU/
lb
is
an
appropriate
level
that
distinguishes
whether
thermal
emission
standards
or
mass
emission
concentration­
based
standards
are
appropriate.
We
also
note
that
no
commenters
suggested
that
we
apply
a
thermal
emissions
format
to
solid
fuel
boilers.
Comment:
Commenters
state
that
thermal
emission
standards
are
inappropriate
because
sources
burning
hazardous
waste
with
a
higher
energy
content
or
higher
percent
hazardous
waste
firing
rate
(
i.
e.,
one
that
fulfills
a
greater
percentage
of
its
total
energy
demand
from
the
hazardous
waste)
would
be
allowed
to
emit
more
HAP.
Response:
Part
of
this
comment
would
apply
regardless
of
what
normalizing
parameter
is
used.
Technology­
based
standards
(
including
MACT
standards)
are
almost
always
expressed
in
terms
of
some
type
of
normalizing
parameter,
i.
e.,
"
X"
amount
of
HAP
may
be
emitted
per
unit
of
normalizing
parameter.
This
allows
a
meaningful
comparison
between
units
of
different
size
and
production
capacity.
A
consequence
is
that
the
overall
mass
of
HAP
emissions
varies,
but
the
rate
of
control
remains
constant
per
the
normalizing
unit.
As
explained
in
the
introduction
to
this
section,
this
approach
is
both
routine
and
permissible.
Cement
kilns,
lightweight
aggregate
kilns,
and
liquid
fuel
boilers
combust
hazardous
waste
to
recover
valuable
energy.
Recovering
energy
is
an
integral
part
of
their
production
process.
As
discussed
at
proposal,
emission
concentration­
based
standards
(
and
the
methodology
that
otherwise
would
be
used
to
calculate
emission
concentration­
based
standards)
may
result
in
standards
that
are
biased
against
sources
that
recover
more
energy
from
hazardous
waste.
69
FR
at
21219.
This
may
discourage
sources
from
recovering
energy
from
hazardous
waste
because
such
standards
do
not
normalize
each
source's
allowable
emissions
based
on
the
amount
of
hazardous
waste
it
processes
for
energy
recovery
purposes.
A
source
that
fulfills
100
percent
of
its
energy
demand
from
hazardous
112
Hazardous
waste
chlorine
feedrates
that
are
included
in
our
database
(
expressed
as
MTECs)
range
from
a
low
of
46,000,000
ug/
dscm
to
a
high
of
294,000,000
ug/
dscm.
On
a
mass
chlorine
percentage
basis,
these
wastes
range
from
17%
to
82%,
noting
that
these
percentages
did
not
include
the
chlorine
that
was
also
spiked
during
the
emissions
tests).
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards",
September
2005,
Section
15.
waste
would
be
required
to
limit
its
mass
HAP
emissions
to
the
same
levels
as
an
identical
source
that
satisfies,
for
example,
only
10
percent
of
its
energy
demand
from
hazardous
waste
and
90%
from
coal.
This
would
inappropriately
discourage
the
safe
recovery
of
energy
from
hazardous
waste,
and
could
in
turn
result
in
greater
consumption
of
valuable
fossil
fuels
that
otherwise
would
be
consumed.
Sources
which
fulfill
a
greater
percentage
of
their
energy
demand
from
hazardous
waste
(
either
by
processing
hazardous
wastes
that
are
higher
in
energy
content,
or
by
simply
processing
more
hazardous
waste)
will
be
allowed
to
emit
more
HAP
(
on
a
mass
emission
rate
basis)
than
an
identical
source
that
satisfies
less
of
its
total
energy
demand
from
hazardous
waste.
This
is
appropriate
because:
1)
the
source
fulfilling
a
greater
percentage
of
its
energy
demand
from
hazardous
waste
is
processing
more
raw
material
than
the
other
source
(
the
raw
material
being
the
energy
content
of
the
waste);
and
2)
the
source
fulfilling
a
lower
percentage
of
its
energy
demand
requirements
from
hazardous
waste
would
not
be
allowed
to
dilute
its
emissions
with
nonhazardous
waste
fuels,
and
we
would
thus
assure
that
all
sources
implement
hazardous
waste
feed
control
to
levels
consistent
with
MACT.
113
This
was
illustrated
in
the
example
provided
in
the
introduction
to
this
comment
response
section.
Similarly,
two
sources
that
combust
hazardous
waste
with
the
same
energy
content
and
the
same
metal
concentrations
(
on
both
a
thermal
concentration
and
mass­
based
concentration
basis),
but
at
different
hazardous
waste
firing
rates,
would
be
required
to
achieve
identical
back­
end
control
device
operating
efficiencies
to
comply
with
a
thermal
emissions­
based
standard.
Holding
these
factors
constant,
thermal
emission
standards
require
sources
to
achieve
identical
percent
reductions
of
the
HAP
that
is
processed
within
the
combustor
via
removal
with
an
air
pollution
control
device.
A
thermal
emission
standard
format
is
thus
equally
stringent
for
these
sources
on
a
percent
HAP
removal
basis,
irrespective
of
the
amount
of
hazardous
waste
it
processes
for
energy
recovery,
and
better
assures
that
sources
burning
smaller
amounts
of
hazardous
waste
(
from
an
energy
recovery
perspective)
are
also
controlling
emissions
as
well
as
the
average
of
the
best
performing
sources.
Sources
processing
higher
energy
content
hazardous
wastes
would
be
allowed
to
feed
hazardous
wastes
with
higher
metal
and
chlorine
mass­
based
concentrations
relative
to
other
sources
combusting
lower
energy
content
wastes.
To
illustrate
this,
assume
there
are
two
sources
(
named
C
and
D)
with
identical
back­
end
control
systems
and
identical
mass
feedrates
of
hazardous
waste.
Also
assume
the
hazardous
waste
of
source
C
has
twice
the
energy
content
as
compared
to
the
hazardous
waste
processed
by
source
D.
A
thermal
emission
standard
will
allow
Source
C
to
feed
a
hazardous
waste
that
has
twice
the
metals
concentration
(
as
measured
on
a
mass
basis)
as
compared
to
source
D,
even
though
both
sources
would
be
required
to
comply
with
equivalent
thermal
feed
rates
limitations.
Notably,
however:
1)
source
C
is
displacing
(
i.
e.,
not
using)
twice
as
much
valuable
fossil
fuel
as
the
source
with
the
lower
energy
content
hazardous
waste,
and
is
feeding
twice
as
much
raw
material
 
the
raw
material
being
energy
content
contained
in
the
hazardous
waste;
2)
source
C
cannot
exceed
the
feed
control
levels
(
expressed
on
a
lbs
of
HAP
per
million
BTU
basis)

113
Although
the
rule
does
not
require
use
of
feed
control
(
or
any
particular
means
of
control
to
achieve
a
standard),
the
rule
assures
that
all
sources'
emissions
will
reflect
the
emissions
of
the
sources
with
the
best
hazardous
waste
federates
expressed
in
terms
of
amount
of
HAP
per
BTU
of
hazardous
waste.
Because
this
format
eliminates
consideration
of
stack
gas
attributable
to
fossil
fuel
emissions,
and
thus
eliminates
the
dilutive
effect
of
these
emissions,
the
likelihood
that
sources
will
in
fact
use
hazardous
waste
feed
control
as
part
of
their
control
strategy
is
great.
that
was
achieved
by
the
average
of
the
best
performing
sources
(
assuming
its
back­
end
control
efficiency
is
equivalent
to
the
average
performance
demonstrated
by
the
best
performing
sources);
and
3)
source
D
is
required
to
have
lower
mass
concentrations
of
metals
in
its
hazardous
waste
because
it
is
firing
poorer
quality
hazardous
waste
fuel
(
from
an
energy
recovery
perspective)
and
because
it
is
feeding
less
of
the
same
raw
material
(
measured
by
energy
content).
Thus,
the
thermal
emissions
format
appropriately
encourages
and
promotes
the
processing
of
clean,
high
energy
content
hazardous
waste
fuels
(
consistent
with
evaluating
hazardous
waste
feed
control
as
an
aspect
of
MACT,
and
not
just
relying
on
control
solely
through
use
of
back
end
technology),
and
does
so
equally
for
all
sources
because
it
normalizes
the
allowable
emissions
based
on
the
amount
of
energy
each
source
recovers
from
the
hazardous
waste.
Put
another
way,
source
C
in
the
above
example
is
controlling
HAP
emissions
to
the
same
extent
as
the
average
of
the
best
performing
sources
per
every
BTU
of
hazardous
waste
fuel
it
processes
(
as
is
source
D).
We
note
that
this
is
a
hypothetical
example.
In
practice
the
average
energy
content
of
hazardous
waste
processed
at
cement
kilns
does
not
vary
significantly
across
sources.
Cement
kilns
burn
hazardous
wastes
with
relatively
consistent
energy
contents
because
that
is
what
their
production
process
necessitates.
This
is
supported
by
our
database
and
by
comments
received
from
the
Cement
Kiln
Recycling
Coalition.
114
Heating
values
of
hazardous
wastes
processed
at
cement
kilns
during
compliance
tests
(
information
which
is
included
in
our
database)
range
from
10,300
to
17,600
BTU/
lb,
with
a
median
value
of
12,400
BTU/
lb.
We
note
that
these
are
snapshot
representations
of
hazardous
waste
heating
content
from
these
sources
that
originate
from
compliance
tests.
We
also
have
long
term
average
hazardous
waste
heating
measurements
from
cement
kilns
indicating
that
the
heating
content
of
the
hazardous
wastes
on
average
range
from
9,900
to
12,200
BTU/
lb,
with
a
median
value
of
11,
500
BTU/
lb.
We
thus
conclude
that
the
commenter's
concern
regarding
sources
being
allowed
to
emit
more
HAP
if
they
process
hazardous
waste
with
higher
energy
content
is
overstated
for
these
sources.
Energy
content
of
hazardous
wastes
processed
in
liquid
fuel
boilers
and
lightweight
aggregate
kilns
varies
more
than
energy
content
of
hazardous
wastes
processed
by
cement
kilns,
and
sources
with
higher
energy
content
wastes
would
be
allowed
to
emit
more
metals
than
identical
sources
burning
identical
volumes
of
lower
energy
content
wastes
(
although
the
degree
of
control
is
identical
per
BTU
of
hazardous
waste
fuel
processed).
115
Again,
these
are
hypothetical
examples.
Each
energy
recovery
unit
will
have
an
upper
bound
on
the
amount
of
energy
it
can
process
from
the
hazardous
waste.
Sources
that
process
higher
energy
content
hazardous
wastes
would
not
necessarily
feed
the
same
volume
of
hazardous
waste
as
compared
to
sources
processing
lower
energy
content
hazardous
wastes
because
they
cannot
exceed
the
thermal
capacity
of
their
combustion
unit.
Under
a
thermal
emission
114
See
comment
submitted
by
the
Cement
Kiln
Recycling
Coalition,
USEPA,
"
Comment
Response
Document
to
the
Proposed
HWC
MACT
Standards,
Volume
1:
MACT
Standards,"
September
2005,
Section
3.3.
Also
see
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
23.
115
The
hazardous
waste
heating
values
of
liquid
fuel
boilers
range
from
2200
to
21000
BTU/
lb,
with
a
median
value
of
14,800.
Heating
values
of
lightweight
aggregate
kilns
range
from
4900
to
16,900
TU/
lb,
with
a
median
value
of
14,800.
We
note
that
the
low
end
heating
value
for
lightweight
aggregate
kilns
reflects
one
source
and
is
not
typical
of
heating
values
used
by
the
other
commercial
lightweight
aggregate
kiln
facilities,
and
are
similar
to
the
heating
values
of
cement
kilns.
standard
format,
the
mass
emission
rates
that
would
be
allowed
for
identical
sources
that
fulfill
100
percent
of
their
energy
demand
from
hazardous
waste
and
that
have
differing
hazardous
waste
energy
contents
would
be
identical.
Although
the
source
with
the
higher
energy
content
hazardous
waste
would
have
a
higher
allowable
mass­
based
hazardous
waste
feed
concentration,
this
source
would
have
to
process
less
hazardous
waste
(
on
a
mass
basis)
to
remain
within
its
thermal
capacity.
This
helps
to
ensure
that
its
mass
HAP
emission
rate
is
similar
to
other
sources
that
process
lower
energy
content
hazardous
waste.
One
commenter's
apparent
concern
with
thermal
emissions
seems
to
center
on
an
assertion
that
sources
will
intentionally
blend
nonhazardous,
high
heating
value
wastes
or
fuels
with
low
energy,
high
metal
bearing
hazardous
wastes
in
order
to
increase
the
energy
content
of
these
metal
bearing
wastes
so
that
they
will
be
subject
to
higher
allowable
emissions
via
thermal
emission
standards.
We
specifically
address
that
comment
later
as
it
relates
to
commercial
energy
recovery
units
(
lightweight
aggregate
kilns
and
cement
kilns).
We
note
here,
however,
that
we
do
not
consider
that
comment
to
be
of
practical
concern
for
liquid
fuel
boilers
because
they
do
not
engage
in
commercial
fuel
blending
practices.
Comment:
A
commenter
states
that
EPA's
assessment
of
thermal
emissions
to
identify
the
relevant
best
sources
is
inappropriate
because
thermal
emissions
are
not
emission
levels,
but
rather
a
ratio
of
emissions
to
the
heat
content
in
a
source's
hazardous
waste.
Response:
This
comment
challenges
the
basic
idea
of
normalization,
since
the
comment
would
be
the
same
regardless
of
the
normalizing
parameter
being
used.
Thermal
emissions
are
emission
levels
that
are
normalized
to
account
for
the
amount
of
energy
(
i.
e.,
raw
material)
these
sources
recover
by
processing
hazardous
waste.
Similarly,
a
mass
emission
concentration
(
i.
e.,
ug/
dscm)
is
a
ratio
of
the
emissions
to
the
volume
of
combustion
gas
that
is
generated,
which
normalize
emissions
to
account
for
differences
in
the
size
of
the
combustion
units
(
as
well
as
differences
in
production
capacity).
This
rulemaking
assesses
performance
and
expresses
emission
standards
in
both
of
these
formats;
both
formats
normalize
the
emissions
so
that
we
may
better
assess
emission
control
efficiencies
equally
across
sources
based
on
the
percent
of
HAP
in
the
feed
(
whether
thermal
feed
or
feed
normalized
based
on
combustor
size)
116
that
is
controlled
or
removed
from
the
stack
gas
prior
to
being
emitted
into
the
atmosphere.
As
discussed
above,
technology­
based
standards
have
historically
assessed
performance
after
normalizing
emissions
based
on
the
amount
of
raw
material
processed
by
the
given
industry
sector.
Thermal
emissions
normalize
each
source's
emissions
based
on
the
amount
of
raw
material
(
hazardous
waste
fuel)
it
processes,
and
are
therefore
appropriate
to
assess
and
identify
the
relevant
best
performers.
Finally,
as
previously
explained,
this
approach
is
consistent
with
both
the
language
of
section
112
(
d)
(
2)
and
(
3),
and
the
purpose
of
these
provisions.
Comment:
A
commenter
states
that
EPA's
assessment
of
thermal
emissions
to
identify
the
relevant
best
sources
is
inappropriate
because
it
ignores
HAP
emissions
attributable
to
the
nonhazardous
fuel
and
raw
material.
Response:
Thermal
emission
standards
do
not
directly
control
HAP
emissions
attributable
to
the
fossil
fuels
and
raw
material,
in
the
sense
that
we
did
not
assess
feed
control
of
fossil
fuels
or
raw
materials.
However,
this
issue
is
not
related
to
our
choice
to
116
For
emission
concentration­
based
standards
we
normalize
hazardous
waste
feed
control
levels
by
calculating
what
we
call
maximum
theoretical
emission
concentrations,
which
are
equivalent
to
the
HAP
mass
feed
rate
divided
by
gas
flow
rate.
use
thermal
content
of
hazardous
waste
as
a
normalizing
parameter.
Rather,
the
issue
is
whether
feed
control
of
fossil
fuels
and
raw
materials
is
a
feasible
means
of
control
at
all.
We
have
determined
that
it
is
not,
and
that
only
back­
end
control
(
expressed
as
system
removal
efficiency)
is
feasible.
Moreover,
today's
rule
controls
emissions
from
HAP
in
raw
material
and
fossil
fuels.
All
non­
mercury
metal
HAP
emissions
attributable
to
fossil
fuels
or
raw
material
are
effectively
and
efficiently
controlled
to
the
level
of
the
average
of
the
best
performing
sources
with
the
surrogate
particulate
matter
standard,
as
well
as
the
system
removal
efficiency
component
of
the
SRE/
Feed
methodology.
Comment:
EPA
has
failed
to
document
sources'
actual
feedrates.
Feedrates
are
presented
either
as
MTECs
(
where
hazardous
waste
HAP
feedrates
are
divided
by
gas
flow
rates)
or
as
thermal
feedrates,
(
where
feedrate
is
expressed
as
the
mass
of
HAP
per
million
BTUs
of
hazardous
waste
fired).
This
is
impermissible,
since
it
does
not
measure
actual
feed
levels.
Response:
This
comment
essentially
takes
the
position
that
it
is
legally
impermissible
to
normalize
standards,
i.
e.,
express
standards
on
a
common
basis.
EPA
rejects
this
comment
for
the
reasons
stated
in
the
introduction
to
this
section.
Comment:
A
commenter
states
that
an
increasing
number
of
fuel
blenders
are
producing
fuels
with
a
minimum
heating
content
and
maximum
metals
content
in
order
to
maximize
revenues
because
high
metal
bearing
wastes
command
a
higher
revenue
on
the
commercial
waste
market.
The
commenter
states
that
thermal
emission
standards
are
not
appropriate
because
they
are
based
on
the
implicit
assumption
that
energy
recovery
entails
metals
feed.
Response:
Contrary
to
what
the
commenter
suggests,
the
thermal
emissions
format
will
more
likely
discourage
the
alleged
practice
of
fuel
blenders
producing
fuels
with
a
minimum
heat
content
and
maximum
metals
content
because
the
standard
limits
the
allowable
metal
emissions
based
on
the
amount
of
energy
contained
in
the
hazardous
waste.
Thus,
a
source
with
a
lower
energy
waste
would
have
to
ensure
that
the
mass
concentration
of
metals
is
also
lower
to
comply
with
the
thermal
emission
formatted
standard.
The
source
would
consequently
emit
less
metals
(
on
a
mass
basis)
because
of
the
lower
metal
mass
concentration
in
the
waste
fuel.
Thermal
emission
standards
reflect
the
reality
that
the
hazardous
waste
fuels
that
are
currently
processed
safely
and
efficiently
in
energy
recovery
units
to
displace
valuable
fossil
fuel
do
in
fact
contain
metal
HAP.
From
a
feed
control
perspective,
the
thermal
emissions
format
appropriately
requires
sources
to
process
high
energy
content
hazardous
waste
fuels
that
reflect
the
thermal
feed
control
levels
achieved
by
the
average
of
the
best
performing
sources,
and
does
so
equally
for
all
sources
because
it
normalizes
the
allowable
emissions
based
on
the
amount
of
energy
each
source
recovers
from
the
hazardous
waste.
Comment:
A
commenter
states
that
EPA
should
be
concerned
that
fuel
blenders
and
kilns
will
use
the
thermal
emission
standard
format
to
increase
the
allowable
metals
feedrates
for
their
units.
The
commenter
claims
that
sources
could
inappropriately
convert
nonhazardous
waste
fuel
to
hazardous
waste
fuel
by
simply
putting
coal
in
a
bunker
in
which
hazardous
waste
was
once
stored,
or
mixing
nonhazardous
waste
fuel
oil
with
hazardous
waste.
The
commenter
states
that
a
facility
with
a
low
hazardous
waste
firing
rate,
and
relatively
low
allowable
emissions
can
become
a
facility
with
a
high
hazardous
waste
percent
firing
rate,
with
higher
allowable
emissions,
simply
by
`
creative'
use
of
the
hazardous
waste
mixture
rule.
The
commenter
suggests
that
EPA
clearly
state
that
the
hazardous
waste
thermal
emission
standards
apply
only
to
the
hazardous
waste
portion
of
the
fuel
blend
mixture.
The
commenter
further
suggests
that
EPA
require
fuel
blenders
to
report
the
amount
of
nonhazardous
waste
fuel
that
is
contained
in
the
fuel
blend,
and
that
cement
kilns
use
this
to
determine
allowable
metal
feed
rates
based
on
the
original
hazardous
waste
energy
content.
Response:
We
do
not
believe
hazardous
waste
combustors
will
engage
in
the
practice
of
redesignating
their
fossil
fuels,
i.
e.,
coal,
as
hazardous
wastes
with
creative
use
of
the
mixture
rule
in
order
to
increase
their
allowable
metal
HAP
emission
rate.
That
would
require
large
quantities
of
coal
to
be
newly
classified
as
hazardous
waste.
The
coal,
and
the
unit
where
the
coal
is
stored,
would
subsequently
become
subject
to
all
applicable
subtitle
C
requirements,
which
include
storage
and
closure/
post
closure
requirements.
We
believe
this
disincentive
will
discourage
this
hypothetical
practice.
Moreover,
as
previously
discussed,
today's
rule
does
not
allow
cement
kiln
or
lightweight
aggregate
kiln
emissions
to
exceed
the
interim
standards.
The
fact
that
we
are
issuing
emission
standards
for
some
pollutants
in
the
thermal
emissions
standard
format
will
not
encourage
fuel
blenders
to
send
more
metals
to
these
commercial
energy
recovery
sources
because
their
allowable
emission
concentrations
are,
by
definition,
either
equivalent
to
or
more
stringent
than
the
current
limitations
with
which
they
are
complying.
Thus,
even
if
the
fuel
blenders
and
energy
recovery
units
engaged
in
this
practice,
they
could
not
emit
more
metals
than
they
are
currently
allowed
to
emit.
We
therefore
conclude
that
it
is
not
necessary
to
promulgate
complicated
regulatory
provisions
that
would
increase
the
reporting
and
recordkeeping
requirements
of
fuel
blenders
and
energy
recovery
units
in
order
to
address
a
hypothetical
scenario
that
likely
would
never
occur.
Finally,
we
note
that
combustion
of
certain
high
HAP
metal
content
wastes
is
already
prohibited
under
RCRA
rules.
See
40
CFR
§
268.3.
Such
wastes
remain
prohibited
from
combustion
even
if
they
are
mixed
with
fossil
fuel
so
that
the
mixture
has
a
higher
energy
content.
U.
S.
v.
Marine
Shale
Processors,
81
F.
3d
1361,
1366
(
5th
Cir.
1996)
(
an
unrecyclable
hazardous
waste
is
not
recycled
when
it
is
mixed
with
a
usable
non­
waste
and
the
mixture
is
processed).
Thus,
the
dilution
prohibition
in
§
268.3
serves
as
a
further
guard
against
the
commenter's
concern.
Comment:
A
commenter
states
that
the
thermal
emissions
format
may
be
problematic
because
it
is
based
on
a
flawed
assumption
that
metal
HAP
from
the
cement
kiln
raw
material
and
hazardous
waste
partition
in
equal
proportions
to
the
total
stack
gas
emissions.
The
commenter
believes
that
metal
retention
in
the
raw
materials
is
higher
than
the
hazardous
waste,
suggesting
that
thermal
emission
standards
allow
an
arbitrary
increase
in
allowable
hazardous
waste
metals
emissions.
The
commenter
suggests
that
EPA
require
that
compliance
demonstrations
be
conducted
only
under
conditions
where
the
metals
content
in
the
hazardous
waste
is
significantly
higher
than
the
metal
content
in
the
raw
material
to
minimize
this
bias.
Response:
The
commenter
has
not
provided
any
emissions
data
to
support
this
claim,
nor
does
the
EPA
know
of
data
available
that
reaches
this
conclusion.
We
do
not
believe
there
is
a
significant
difference
in
the
partitioning
rates
of
these
metals
in
a
cement
kiln.
117
117
We
reference
comments
submitted
by
the
cement
kiln
recycling
coalition
that
address
this
very
point.
See
USEPA,
"
Comment
Response
Document
to
the
Proposed
HWC
MACT
Standards,
Volume
1:
MACT
Standards,"
September
2005,
Section
3.3.
We
have
evaluated
these
comments
and
find
them
persuasive
on
this
issue.
Even
if
there
is
a
difference,
this
would
not
result
in
an
arbitrary
increase
of
allowable
hazardous
waste
metals
emissions.
The
thermal
emission
standards
were
calculated
using
thermal
emissions
data
that
are
based
on
each
source's
compliance
test.
These
tests
were
conducted
at
hazardous
waste
feed
control
levels
that
represented
the
upper
bound
of
feed
control
levels
these
sources
see
on
a
day­
to­
day
basis.
To
accomplish
this,
sources
spiked
metals
into
the
hazardous
waste
prior
to
combusting
the
wastes.
The
amount
of
metals
that
were
contained
in
the
hazardous
waste
streams,
after
accounting
for
these
spiked
metals,
far
exceeded
the
metal
levels
that
were
contained
in
the
raw
material.
Thus
the
differences
in
partitioning,
if
any,
would
likely
be
overshadowed
by
the
fact
that
the
majority
of
the
metals
were
contained
in
the
hazardous
waste.
Notably,
any
partitioning
bias
that
that
may
be
present
would
also
have
been
present
during
these
compliance
tests.
As
a
result,
this
potential
bias
would
be
built
into
the
emission
standard
and
thus
would
not
result
in
an
arbitrary
increase
in
allowable
hazardous
waste
metals
emissions
because
these
sources
will
again
demonstrate
compliance
under
testing
conditions
similar
to
those
used
to
generate
the
data
used
to
calculate
the
MACT
floors.
We
conclude
that
it
is
not
necessary
to
provide
additional
prescriptive
regulatory
language
that
would
require
sources
to
demonstrate
system
removal
efficiencies
under
testing
conditions
that
exhibit
a
high
ratio
of
hazardous
waste
metal
content
to
raw
material
metal
content
because
the
regulations
implicitly
require
sources
to
demonstrate
hazardous
waste
metal
feed
control
levels
that
represent
the
upper
range
of
their
allowable
feed
control
levels.
118
Comment:
A
commenter
states
that
compliance
with
standards
expressed
in
a
thermal
emissions
format
is
problematic
because
the
measurement
of
energy
content
of
hazardous
waste
fuel
blends
is
subject
to
significant
variability
due
to
the
nature
of
the
test.
The
commenter
also
claims
that
heating
value
measurements
of
waste
streams
that
are
mixtures
of
solids
and
liquids
tend
be
biased
high,
which
would
inappropriately
give
these
sources
higher
allowable
metal
emission
limitation.
Response:
There
are
standard
ASTM
procedures
that
reliably
measure
the
energy
content
of
the
hazardous
waste.
Any
parameter
that
is
measured
for
compliance
purposes
is
subject
to
method
imprecision
and
variability.
We
do
not
believe
that
hazardous
waste
energy
content
measurements
result
in
imprecision
and
variability
above
and
beyond
the
measurement
methods
that
are
currently
used
to
assure
compliance
with
emission
concentration­
based
standards.
The
commenter
did
not
provide
evidence
that
supports
the
claim
that
energy
content
measurement
and/
or
sampling
methods
consistently
result
in
a
positive
bias.
If
a
bias
were
consistently
present
for
these
types
of
wastes,
then
one
would
expect
it
to
be
also
reflected
in
the
measured
data
for
which
we
based
the
emission
standards,
which
would
fully
address
the
commenter's
concern.
Nonetheless,
we
note
that
all
hazardous
waste
sampling
and
analysis
procedures
must
be
prescribed
in
each
source's
feedstream
analysis
plan,
which
can
be
reviewed
by
the
permitting
authority
upon
request.
These
feedstream
analysis
plans
must
ensure
that
sampling
and
analysis
procedures
are
unbiased,
precise,
and
that
the
results
are
representative
of
the
feedstream.
See
§
63.1208(
b)(
8).
More
information
on
obtaining
a
118
Although
today's
final
rule
allows
sources
to
extrapolate
their
allowable
hazardous
waste
feed
control
levels
to
levels
that
are
higher
than
the
level
demonstrated
in
the
comprehensive
performance
test,
sources
must
still
spike
metals
into
the
hazardous
waste
during
the
test
in
order
to
assure
that
the
system
removal
efficiency
used
for
the
extrapolation
procedure
is
reliable
and
accurate.
representative
samples
can
be
found
in
EPA's
SW­
846
publication.
119
These
procedures
involve
acquiring
several
sub­
samples
that
provide
integration
over
the
breadth,
depth
and
surface
area
of
the
waste
container
and
obtaining
replicate
samples
(
see
Ch.
13.3.1
of
SW­
846).
Comment:
A
commenter
states
that
BTU
measurements
can
be
reported
as
either
a
higher
heating
value
or
a
lower
heating
value,
and
suggests
that
EPA
require
sources
to
use
the
lower
heating
value
calculation
when
determining
allowable
hazardous
waste
feed
control
levels.
The
commenter
seems
to
imply
that
use
of
higher
heating
values
will
inappropriately
result
in
higher
allowable
metal
feed
rates
for
fuel
blends
that
contain
aqueous
waste.
Response:
The
BTU
data
in
our
database
that
we
use
to
calculate
the
emission
standards
reflect
higher
heating
values.
It
is
standard
practice
in
the
incineration/
combustion
industry
to
report
the
gross
heat
of
combustion
(
or
higher
heating
value).
We
conclude
that
sources
should
use
the
higher
heating
value
rather
than
the
lower
heating
value
for
all
compliance
determinations
because
these
are
method­
based
emission
standards.
Fuel
blends
that
contain
aqueous
wastes
will
not
be
inappropriately
rewarded
with
higher
allowable
feed
rates
because
any
fuel
mixture
that
contain
aqueous
mixtures
will
have
lower
reported
heating
values,
irrespective
of
whether
they
are
reported
as
higher
heating
values
or
lower
heating
values.
120
E.
Standards
Can
Be
No
Less
Stringent
Than
the
Interim
Standards
Comment:
Several
commenters
oppose
EPA's
position
in
the
proposed
rule
that
the
replacement
standards
can
be
promulgated
at
a
level
no
less
stringent
than
the
interim
standards
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
In
instances
where
the
calculated
replacement
standard
is
less
stringent
than
the
interim
standard,
the
commenters
oppose
EPA's
position
of
"
capping"
the
replacement
standard
at
the
level
of
the
interim
standard
to
prevent
backsliding
from
those
levels.
Instead,
commenters
recommend
that
EPA
calculate
and
finalize
the
existing
and
new
source
floor
levels
without
regard
to
the
interim
standards.
One
commenter
also
notes
that
the
interim
standards
are
simply
a
placeholder
without
the
necessary
statutory
basis
to
qualify
as
emission
limitations
for
purposes
of
establishing
MACT
floors.
Another
commenter,
however,
supports
EPA's
position
to
prevent
backsliding
to
levels
less
stringent
than
the
interim
standards.
Response:
We
maintain
that
the
replacement
standards
can
be
no
less
stringent
than
existing
standards,
including
the
interim
standards
under
§
§
63.1203­
1205,
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
These
standards
were
promulgated
on
February
13,
2002,
and
sources
were
required
to
comply
with
them
no
later
than
September
30,
2003,
unless
granted
a
one­
year
extension
(
see
§
63.1206(
a)).
Thus,
all
hazardous
waste
combustors
are
currently
complying
with
the
interim
standards.
The
comment
that
the
standards
lack
some
type
of
requisite
statutory
pedigree
misses
the
central
point
of
our
interpretation
of
the
statute:
motivation
for
achieving
a
standard
(
be
it
regulatory
compulsion,
statutory
requirement,
or
some
other
reason)
is
irrelevant
in
determining
levels
of
MACT
119
SW­
846,
"
Test
Methods
for
Evaluating
Solid
Waste,
Physical/
Chemical
Methods
120
The
difference
between
the
higher
heating
value
and
lower
heating
value
of
an
aqueous
waste
is
insignificant
relative
to
the
difference
in
heating
value
between
an
aqueous
waste
and
an
organic
liquid
waste
fuel.
floors.
National
Lime
v.
EPA,
233
F.
3d
at
640.
What
matters
is
the
level
of
performance,
not
what
motivated
that
level.
As
a
result,
the
replacement
standards
promulgated
today
ensure
that
sources
will
emit
HAP
at
levels
no
higher
than
levels
achieved
under
current
regulations.
We
do
this
in
this
rule,
when
necessary,
by
either
capping
a
calculated
floor
level
by
the
interim
standard
(
when
both
the
calculated
floor
level
and
interim
standard
are
expressed
in
the
same
format
of
the
standard)
or
by
adopting
dual
standards
in
cases
where
formats
of
the
standard
vary
(
so
that
comparison
of
stringency
cannot
be
uniformly
determined
(
as
for
cement
kilns
and
lightweight
aggregate
kilns,
as
explained
in
the
preceding
section
above
and
in
the
following
response).
In
this
case,
the
sources
are
subject
to
both
the
replacement
and
interim
standards.
Comment:
One
commenter
states
that
some
proposed
standards
expressed
in
a
thermal
emissions
format
would
allow
some
sources
to
emit
semivolatile
metals
at
levels
higher
than
the
interim
standard.
The
commenter
states
that
EPA
reached
incorrect
conclusions
when
making
relative
stringency
comparisons
between
standards
expressed
in
a
thermal
emissions
and
mass
concentrations
format
because,
in
part,
EPA
assumed
an
average
F­
factor
(
e.
g.,
semivolatile
metals
for
cement
kilns).
121
In
addition,
the
commenter
notes
that
the
actual
relationship
between
standards
expressed
in
terms
of
thermal
emissions
and
mass
concentrations
is
complex
and
depends
on
a
number
of
factors.
As
a
result,
the
commenter
urges
EPA
to
adopt
dual
standards
(
i.
e.,
promulgate
the
MACT
standard
as
both
the
standard
expressed
in
a
thermal
emissions
format
and
also
the
interim
standard
expressed
in
a
mass
concentration
format)
to
prevent
backsliding.
Response:
Even
though
a
source
may
operate
in
compliance
with
a
standard
expressed
in
a
thermal
emission
format,
a
source
may
or
may
not
also
be
in
compliance
with
the
corresponding
mass
concentration
interim
standard
(
e.
g.,
the
semi­
and
low
volatile
metal
emission
standards
for
cement
and
lightweight
aggregate
kilns
of
§
§
63.1204
and
63.1205,
respectively).
As
reflected
in
the
comment,
making
a
judgment
as
to
whether
a
replacement
standard
is
more
stringent
than
the
interim
standard
for
the
HAP
is
not
always
a
straightforward
calculation.
As
we
discussed
in
the
proposed
rule122
and
echoed
by
the
commenter,
comparing
standards
in
the
thermal
emissions
format
to
those
in
a
mass
concentration
format
involves
assumptions
that
vary
on
a
site­
specific
basis
and
can
vary
over
time,
including
the
hazardous
waste
fuel
replacement
rate,
contributions
to
emissions
from
nonhazardous
waste
inputs
such
as
raw
materials
and
nonhazardous
waste
fuels
such
as
coal,
how
close
to
the
standard
a
source
elects
to
comply,
the
system
removal
efficiency
demonstrated
during
testing,
and
the
type
and
composition,
including
heating
value,
of
fuels
burned.
To
ensure
that
sources
operating
under
standards
expressed
in
a
thermal
emissions
format
will
not
emit
HAP
metals
at
levels
higher
than
currently
achieved
under
the
interim
standards,
we
adopt
a
dual
standard
to
prevent
emissions
increasing
to
levels
higher
than
the
interim
standards.
The
dual
standard
structure
includes
both
the
standard
expressed
in
a
thermal
emissions
format
and
the
interim
standard,
which
is
expressed
in
a
mass
concentration
format.
We
apply
this
concept
to
several
standards
including
semivolatile
121
An
F­
factor
is
an
estimate
of
the
amount
of
combustion
gas
volume
that
is
generated
per
fuel
heat
input
for
a
given
type
of
fuel,
expressed
in
units,
for
example,
cubic
feet
of
combustion
gas
per
million
British
thermal
units
(
Btu)
of
fuel
burned.
In
the
proposal,
EPA
used
F­
factors
to
convert
the
emission
standards
expressed
on
a
thermal
basis
to
mass
concentrations
in
order
to
make
a
judgment
as
to
the
relative
stringency
of
the
proposed
MACT
standards
relative
to
the
interim
standards.
122
For
example,
see
69
FR
at
21255­
258,
267­
271.
metals,
low
volatile
metals,
and
mercury123
for
cement
kilns
and
semivolatile
metals
and
low
volatile
metals
for
lightweight
aggregate
kilns.
This
approach
ensures
that
sources
are
not
emitting
HAP
metals
above
the
levels
of
the
interim
standards
because
we
cannot
reliably
determine
that
emissions
under
a
standard
expressed
in
a
thermal
emissions
format
would
not
exceed
the
interim
standard
for
all
sources
in
the
category.
See
§
§
63.1220(
a)(
2)­(
a)(
4),
and
(
b)(
2)­(
b)(
4)
and
63.1221(
a)(
3)­(
a)(
4)
and
(
b)(
3)­(
b)(
4).
We
evaluated
the
relative
stringency
of
the
standards
expressed
in
the
thermal
emissions
format
compared
to
the
interim
standards
for
the
entire
source
category
in
order
to
determine
if
the
dual
standard
scheme
could
be
avoided.
We
determined
that
we
could
not.
For
some
HAP
groups
we
found
that
many
sources
in
the
category
would
have
the
potential
to
exceed
the
interim
standards
for
that
HAP.
124
In
this
case,
we
considered
simply
"
capping"
the
standard
expressed
in
the
thermal
emission
format
by
the
interim
standard
(
i.
e.,
the
promulgated
standard
would
only
be
expressed
in
a
mass
concentration
format).
However,
we
conclude
that
this
approach
would
not
be
appropriate
because
the
standard
expressed
in
a
thermal
emission
format
would
likely
be
more
stringent
than
the
mass
concentration
for
some
sources,
and
the
statute
requires
that
MACT
floors
reflect
this
superior
level
of
performance.
In
other
cases
we
found
that
the
standards
expressed
in
the
thermal
emissions
format
would
not
likely
exceed
the
interim
standards
by
the
majority
of
sources
operating
under
typical
conditions.
125
While
our
analysis
(
based
on
information
in
our
data
base)
shows
in
these
cases
that
the
emission
standard
expressed
in
a
thermal
emission
format
would
not
likely
result
in
an
exceedance
of
the
interim
standard,
this
conclusion
may
not
be
true
because
the
assumptions
may
not
be
valid
for
a
particular
source
or
site­
specific
factors
may
change
in
future
operations.
For
example,
HAP
metal
emissions
could
increase
over
time
due
to
increases
in
HAP
contributions
from
raw
materials
or
alternative
raw
materials.
Given
this
potential,
we
adopt
dual
standards
for
the
HAP
metal
standards
in
order
to
ensure
that
standards
expressed
in
a
thermal
emissions
format
will
not
exceed
emission
levels
achieved
under
the
interim
standards.
126
Comment:
Several
commenters
state
that
the
interim
standards
do
not
reflect
the
average
performance
of
the
best
sources,
and
so
cannot
be
the
basis
for
floor
levels.
Response:
In
those
few
situations
where
we
have
established
floor
levels
at
the
level
of
the
interim
standards,
we
have
done
so
as
the
best
means
of
estimating
performance
of
the
best
performing
sources.
Based
on
the
available
data
to
us,
the
average
of
the
best
123
Although
the
mercury
standard
promulgated
for
cement
kilns
is
not
expressed
using
a
thermal
emission
format
basis,
the
same
concept
applies
because
the
mercury
standard
is
a
hazardous
waste
feed
concentration
standard,
which
is
a
different
format
than
the
interim
standard.
124
An
example
for
each
category
is
semivolatile
metals
thermal
emissions
standard
for
existing
cement
and
lightweight
aggregate
kilns.
See
USEPA,
"
Final
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
Section
23.1,
September
2005.
125
An
example
is
the
emission
standards
for
low
volatile
metals
for
existing
and
new
cement
kilns
and
new
lightweight
aggregate
kilns.
See
USEPA,
"
Final
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
Section
23.1,
September
2005.
126
In
response
to
a
comment
regarding
the
implementation
of
dual
standards,
we
note
the
promulgation
of
a
new
provision
allowing
sources
to
petition
the
Administrator
to
waive
the
HAP
metal
feedrate
operating
parameter
limits
for
either
the
emissions
standards
expressed
in
a
thermal
emissions
format
(
or
the
mercury
feed
concentration
standard
for
cement
kilns)
or
the
interim
standards
based
on
documentation
that
the
feedrate
operating
parameter
limit
is
not
needed
to
ensure
compliance
with
the
relevant
standard
on
a
continuous
basis.
See
new
§
63.1209(
g)(
1)(
iv)
and
Comment
Response
Document,
Volume
I,
Section
3.5.
performing
sources
exceeds
the
level
of
the
interim
standards
in
a
few
instances.
Under
these
circumstances,
the
binding
regulatory
limit
becomes
the
best
means
available
to
us
to
estimate
performance.
See
Mossville,
370
F.
3d
at
1241­
42
(
accepting
regulatory
level
as
a
floor
standard
where
sources'
measured
performance
is
not
a
valid
means
of
determining
floor
levels,
and
where
such
data
contains
results
as
high
as
those
regulatory
levels).

F.
How
Can
EPA's
Approach
to
Assessing
Variability
and
its
Ranking
Methodologies
be
Reasonable
when
they
Result
in
Standards
Higher
than
the
Interim
Standards?

A
commenter
argued
that
EPA's
floor
methodologies,
in
particular
its
consideration
of
variability
beyond
that
demonstrated
in
single
test
conditions,
the
SRE/
feed
and
Air
Pollution
Control
Device
methodologies,
must
be
arbitrary
because
in
a
few
instances
projected
standards
using
these
approaches
were
higher
than
the
current
interim
standards,
a
level
every
source
(
not
just
the
best
performers)
are
achieving.
Commenters
also
noted
that
one
of
the
new
source
standards
calculated
under
these
approaches
was
higher
than
an
existing
source
standard,
another
arbitrary
result.
EPA
believes
that
these
seeming
anomalies
(
which
are
infrequent)
result
from
the
database
used
to
calculate
performance
and
standards,
rather
than
from
the
approaches
to
assessing
variability
or
the
two
questioned
floor
methodologies.
The
data
base
is
from
test
results
which
preceded
EPA's
adoption
of
the
interim
standards.
Thus,
the
level
of
performance
required
by
the
later
rule
is
not
necessarily
reflected
in
pre­
rule
test
data.
In
confirmation,
some
of
the
standards
computed
using
straight
emission
approaches
also
are
higher
than
the
interim
standards.
Other
anomalies
arise
simply
due
to
scarcity
of
data
(
floor
levels
for
certain
HAP
emitted
by
lightweight
aggregate
kilns
especially,
where
there
are
only
nine
sources
total).
In
these
situations
there
is
a
greater
likelihood
that
one
or
more
of
the
best
performing
sources
will
have
relatively
high
emissions
because
we
are
required
to
use
data
from
five
sources
to
comprise
the
MACT
pool
whenever
we
have
data
from
fewer
than
30
sources,
and
a
small
amount
of
data
can
skew
the
result.
See
§
112(
d)(
3)(
B).
127
For
example,
many
of
the
calculated
new
source
chlorine
floors
were
slightly
higher
than
the
calculated
existing
source
standards
because
we
assumed
all
sources
with
measured
emissions
below
20
ppmv
were
in
fact
emitting
at
20
ppmv
(
see
part
four,
section
I.
C).
We
generally
are
unable
to
differentiate
a
single
best
performing
source
among
these
best
performers
because
many/
all
of
the
best
performing
sources
emissions
are
adjusted
to
the
same
emission
level.
The
calculated
new
source
floor
can
be
slightly
higher
than
the
existing
source
floor
because
the
variability
factor
that
is
applied
to
the
single
best
performing
source
is
based
on
only
one
test
condition
(
with
three
emission
test
runs).
This
results
in
a
higher
level
of
uncertainty
relative
to
the
existing
source
standard,
which
is
based
on
a
compilation
of
emissions
data
from
several
sources
that
have
essentially
the
same
projected
emissions
as
a
result
of
the
method
bias
correction
factor.
The
variability
factor
that
is
applied
to
the
emissions
of
the
single
best
performing
source
is
therefore
higher
than
the
variability
factor
for
the
existing
source
floor
because
there
are
fewer
degrees
of
freedom
in
the
statistical
analysis.
128
Likewise,
many
of
the
calculated
solid
fuel
boiler
new
source
standards
were
127
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
19,
for
further
discussion.

128
For
a
single
test
condition
the
t
factor
used
in
variability
factor
calculation
has
n­
1
degrees
of
freedom
where
n
is
the
number
of
runs
for
that
condition.
For
the
MACT
floor
calculation
the
t
factor
has
X­
N
degrees
slightly
higher
than
the
calculated
existing
source
standards
because,
as
discussed
above,
there
are
fewer
degrees
of
freedom
when
assessing
the
variability
from
a
single
best
performing
source.
The
solid
fuel
boiler
"
anomalies"
also
occur
using
a
straight
emissions
methodology.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September,
2005,
Section
19,
for
further
discussion
that
summarizes
and
explains
these
so­
called
anomalies.

IV.
Use
of
Surrogates
A.
Particulate
Matter
as
Surrogate
for
Metal
HAP
Comment:
A
commenter
states
that
EPA's
use
of
particulate
matter
as
a
surrogate
for
nonenumerated
metals
is
unlawful
and
arbitrary
and
capricious
because
although
particulate
matter
emissions
may
provide
some
indication
of
how
good
a
source's
end­
of
stack
control
of
such
metals
is,
it
does
not
indicate
what
its
actual
metal
emission
levels
are.
129
The
commenter
states
that
emissions
of
these
metals
can
vary
based
on
metal
feed
rate
without
having
any
appreciable
effect
on
particulate
matter
emission
levels.
Thus
a
particulate
matter
standard
does
not
necessarily
ensure
that
metal
emissions
are
reduced
to
the
metal
emission
levels
achieved
by
the
relevant
best
performing
sources.
To
support
this
assertion,
the
commenter
states
that
EPA
is
on
record
saying
"
low
particulate
matter
emissions
do
not
necessarily
guarantee
low
metal
HAP
emissions,
especially
in
instances
where
the
hazardous
waste
feeds
are
highly
concentrated
with
metal
HAP."
69
Fed.
Reg.
at
21221.
Response:
The
final
rule
uses
a
particulate
matter
standard
as
a
surrogate
to
control:
1)
emissions
of
nonenumerated
metals
that
are
attributable
to
all
feedstreams
(
both
hazardous
waste
and
remaining
inputs);
and
2)
all
nonmercury
metal
HAP
emissions
(
both
enumerated
and
nonenumerated
metal
HAP)
from
the
nonhazardous
waste
process
feeds
at
cement
kilns,
lightweight
aggregate
kilns,
and
liquid
fuel
boilers
(
e.
g.,
emissions
attributable
to
coal
and
raw
material
at
a
cement
kiln,
and
emissions
attributable
to
fuel
oil
for
liquid
fuel
boilers).
Incinerators,
liquid
and
solid
fuel
boilers
may
elect
to
comply
with
an
alternative
to
the
particulate
matter
standard
that
would
limit
emissions
of
all
the
semivolatile
metal
HAPs
and
low
volatile
metal
HAPs.
See
§
63.1219(
e).
The
particulate
matter
standard
is
a
necessary,
effective,
and
appropriate
surrogate
to
control
nonmercury
metal
HAPs.
The
record
demonstrates
overwhelmingly
that
when
a
hazardous
waste
combustor
emits
particulate
matter,
it
also
emits
nonmercury
HAP
metals
as
part
of
that
particulate
matter,
and
that
when
particulate
matter
is
removed
from
of
freedom
where
X
is
the
total
number
of
runs
from
all
sources
in
the
MACT
pool
and
N
is
the
number
of
sources
in
the
pool.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September,
2005,
Section
7.1
for
more
information
on
the
floor
calculation
procedure.
129
"
Enumerated"
metals
are
those
HAP
metals
directly
controlled
with
an
emission
limit,
i.
e.,
lead,
cadmium,
chromium,
arsenic
and
beryllium.
The
remaining
nonmercury
metal
HAP
(
i.
e.,
antimony,
cobalt,
manganese,
nickel,
and
selenium)
are
called
"
nonenumerated"
metal
HAP
(
note
that
arsenic
and
berrylium
are
nonenumerated
metals
for
liquid
fuel
boilers
because
the
low
volatile
metal
emission
standard
applies
only
to
chrome).
emissions
the
nonmercury
HAP
metals
are
removed
with
it.
130
Nonmercury
metal
HAP
emissions
are
therefore
reduced
whenever
particulate
matter
emissions
are
reduced.
The
particulate
matter
standard
thus
is
an
effective
and
appropriate
surrogate
that
assures
sources
are
controlling
these
metal
HAP
with
an
appropriate
back­
end
control
technology.
National
Lime
v.
EPA,
233
F.
3d
at
639.
The
nonenumerated
metal
HAP
are
no
different
than
other
semivolatile
or
low
volatile
metals
in
that
they
also
will
be
effectively
controlled
with
a
back­
end
particulate
matter
air
pollution
control
device.
We
also
considered
the
possibility
of
developing
a
standard
for
nonenumerated
HAP
metals
instead
of
a
PM
standard
(
i.
e.,
regulating
these
metals
directly,
rather
than
through
use
of
a
surrogate).
We
conclude
for
several
reasons,
however,
that
issuing
emission
standards
for
these
nonenumerated
metals
in
lieu
of
a
particulate
matter
standard
would
not
adequately
control
nonmercury
metal
HAPs
to
levels
achieved
by
the
relevant
best
performing
sources.
We
generally
lack
sufficient
compliance
test
emissions
data
for
the
noneneumerated
metals
to
assess
the
relevant
best
performing
sources,
because,
as
discussed
below,
most
of
these
metals
were
not
directly
regulated
pursuant
to
RCRA
air
emission
standards.
131
Although
we
have
more
emissions
data
for
these
metals
that
are
based
on
(
so
called)
normal
operations,
we
still
lack
sufficient
emissions
data
to
establish
nonenumerated
metal
standards
for
all
the
source
categories.
Use
of
normal
data
may
also
be
problematic
because
of
the
concern
raised
by
the
cement
kiln
and
lightweight
aggregate
kiln
stakeholders
that
our
normal
metals
emissions
data
obtained
from
compliance
tests
are
not
representative
of
the
range
of
actual
emissions
at
their
sources.
Cement
kiln
and
lightweight
aggregate
kiln
stakeholders
submitted
long­
term
hazardous
waste
mercury
feed
control
data
that
support
their
assertion.
Although
these
stakeholders
did
not
submit
longterm
normal
hazardous
waste
feed
control
data
for
the
nonenumerated
metals,
we
can
still
see
that
use
of
the
normal
nonenumerated
metal
snapshot
emissions
in
our
database
to
determine
MACT
floors
could
raise
similar
concerns
with
respect
to
whether
the
normal
data
in
fact
represents
average
emissions
at
these
sources,
and
their
level
of
performance.
Use
of
particulate
matter
emissions
data
to
assess
the
relevant
best
performers
for
nonenumerated
metal
HAP
is
therefore
more
appropriate
for
two
reasons.
Compliance
test
data
better
account
for
emissions
variability
and
avoid
the
normal
emissions
bias
discussed
above.
We
also
have
much
more
particulate
matter
emissions
data
from
more
sources,
which
better
allows
us
to
evaluate
the
true
range
of
emissions
from
all
the
sources
within
the
source
category
and
to
assess
and
identify
the
relevant
top
performing
12
percent
of
the
sources.
It
would
be
inappropriate
to
assess
total
stack
gas
emissions
of
nonenumerated
metals
for
cement
kiln
and
lightweight
aggregate
kilns
when
determining
the
relevant
best
performers
because
these
emissions
would,
in
part,
reflect
the
metal
feed
levels
in
these
130
This
statement
is
equally
true
for
any
emitting
source,
not
just
hazardous
waste
combustors.
It
is
well
established
that
semivolatile
and
low
volatile
metals
exist
in
solid
particulate
form
at
typical
air
pollution
control
device
operating
temperatures.
This
is
supported
by
1)
known
operating
temperature
ranges
of
air
pollution
control
devices
used
by
hazardous
waste
combustors;
2)
known
metal
volatility
equilibrium
relationships;
and
3)
extensive
technical
literature.
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
3.1.

131
At
best,
we
may
have
enough
compliance
test
data
for
antimony
and
selenium
to
adequately
assess
relevant
best
performers
for
only
incinerators
and
lightweight
aggregate
kilns.
sources'
nonhazardous
waste
process
feedstreams.
This
is
not
appropriate
because
nonhazardous
process
feedstream
control
is
not
a
feasible
means
of
control.
See
part
four,
section
III.
B.
1.
A
potential
solution
to
this
problem
would
be
to
identify
the
relevant
best
performers
by
assessing
each
source's
hazardous
waste
thermal
emissions
for
these
nonenumerated
metals
(
given
that
hazardous
waste
thermal
emissions
exclude
by
definition
emissions
attributable
to
inputs
other
than
hazardous
waste,
i.
e.
raw
materials
and
fossil
fuels).
This,
however,
would
be
problematic
because,
aside
from
the
data
limitation
issues,
the
majority
of
the
nonenumerated
metals
data
reflect
normal
emissions
which
often
do
not
contain
the
highest
feed
rates
used
by
the
source.
As
a
result,
we
cannot
assess
performance
on
a
thermal
emissions
basis
because
of
the
uncertainty
associated
with
system
removal
efficiencies
at
such
low
metal
feedrates.
Furthermore,
even
if
we
could
issue
hazardous
waste
thermal
emissions
standards
for
these
metals,
a
particulate
matter
emission
standard
would
still
be
necessary
to
control
nonmercury
metal
HAP
emissions
from
the
nonhazardous
waste
process
feedstreams.
Emission
standards
for
these
nonenumerated
metals
could
require
sources
to
implement
hazardous
waste
feed
control
(
for
these
metals)
to
comply
with
the
standard.
132
We
are
less
assured
that
these
sources
were
implementing
hazardous
waste
feed
control
for
these
nonenumerated
metals
at
the
time
they
conducted
the
emissions
tests
(
which
serve
as
the
basis
for
floor
calculations)
because
most
of
these
metals
were
never
directly
regulated
pursuant
to
the
RCRA
emission
standards.
133
This
means
that
sources
tended
to
optimize
(
or
at
least
concentrate
their
efforts
on)
control
of
the
metals
that
are
regulated.
Although
these
metals
were
being
controlled
with
each
source's
back­
end
control
device,
sources
may
not
have
been
controlling
these
metal
feedrates
because
they
probably
were
not
subject
to
specific
feedrate
limitations
(
feed
control
of
the
enumerated
metal
HAP
does
not
ensure
feed
control
of
these
nonenumerated
metal
HAP).
Furthermore,
simultaneous
feed
control
of
all
these
metals,
when
combined
with
enumerated
semivolatile
and
low
volatile
metals,
may
not
be
possible
because
the
best
performing
sources
for
all
these
metals
may
collectively
represent
a
hazardous
waste
feedstream
that
does
not
exist
in
practice
(
from
a
combined
metal
concentration
perspective)
because
there
likely
would
be
different
best
performers
for
each
of
the
metal
HAP
or
metal
HAP
groups.
134
We
thus
conclude
that
back­
end
control
as
measured
and
assessed
by
each
source's
particulate
matter
emissions
is
132
Sources
that
otherwise
would
be
equipped
with
what
is
considered
to
be
a
MACT
back­
end
control
devices
(
i.
e.,
a
control
device
achieving
the
final
rule
particulate
matter
standard)
may
not
be
able
to
achieve
these
metal
emissions
standards
due
to
varying
metal
feed
levels
(
both
within
sources
and
across
sources).
Such
an
outcome
may
require
a
source
to
limit
the
amount
of
metal
that
is
fed
into
the
combustion
unit
to
achieve
the
standard.
133
Antimony
is
the
only
nonenumerated
metal
that
is
directly
regulated
pursuant
to
the
boilers
and
industrial
furnace
regulations.
See
§
266.106.
134
We
generally
cannot
combine
these
nonenumerated
metals
into
the
associated
semivoltile
or
low
volatile
metal
volatility
groupings
promulgated
in
this
final
rule
for
purposes
of
establishing
"
grouped"
emission
standards
because
we
cannot
mix
compliance
test
data
with
normal
emissions
data
when
calculating
floors
(
the
majority
of
the
standards
included
in
this
final
rule
are
based
on
compliance
test
data,
and
the
majority
of
the
data
we
have
for
nonenumerated
metals
being
normal).
Furthermore,
if
we
were
to
separately
group
the
normal
nonenumerated
metal
emission
data
into
their
associated
semivolatile
or
low
volatile
metal
group,
we
may
encounter
data
limitation
issues
because
each
source
would
need
to
have
measured
each
of
the
nonenumerated
metals
in
that
associated
metal
volatility
group
in
order
for
us
to
conclude
that
the
emission
data
adequately
represents
the
sources
combined
emissions
of
semivolatile
or
low
volatile
metals.
the
appropriate
floor
technology
to
assess
when
identifying
the
relevant
best
performers
for
nonenumerated
HAP
metals
and
estimating
these
sources'
level
of
performance.
Comment:
A
commenter
states
that
EPA's
rationale
for
use
of
particulate
matter
as
a
surrogate
for
nonenumerated
metals
is
flawed
because
EPA
has
provided
no
data
in
the
proposal
to
justify
its
hypothesis
that
particulate
matter
is
an
appropriate
surrogate
for
nonenumerated
metal
HAP.
The
commenter
also
states
that
the
proposed
emission
standards
for
particulate
matter
for
existing
sources
discriminate
against
boilers
and
process
heaters
that
burn
clean
(
i.
e.,
little
or
very
low
concentrations
of
HAP
metals)
hazardous
waste
fuels.
The
commenter
suggests
that
if
there
are
sufficient
data,
EPA
should
consider
developing
an
alternative
emission
standard
for
total
HAP
metals
for
new
and
existing
liquid
fuel
boilers,
as
was
done
for
the
Subpart
DDDDD
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial/
Commercial/
Institutional
Boilers
and
Process
Heaters.
Response:
As
previously
discussed
in
this
section,
particulate
matter
reflects
emissions
of
nonmercury
metal
HAPs
because
these
compounds
comprise
a
percentage
of
the
particulate
matter
(
provided
these
metals
are
fed
into
the
combustion
unit).
The
technologies
that
have
been
developed
and
implemented
to
control
particulate
matter
also
control
nonmercury
metal
HAP.
Since
non­
mercury
metal
HAP
is
a
component
of
particulate
matter,
we
can
use
particulate
matter
as
a
surrogate
for
these
metals.
Further
justification
for
the
use
of
particulate
matter
as
a
surrogate
to
control
metal
HAP
is
included
in
the
technical
support
document.
135
We
conclude
that
we
do
not
have
enough
nonenumerated
metal
emissions
data
to
calculate
alternative
total
metal
emission
floors
for
liquid
fuel
boilers.
The
most
problematic
of
these
metals
are
manganese
and
cobalt,
where
we
have
emission
data
from
only
three
sources.
We
have
much
more
compliance
test
particulate
matter
emissions
data
from
liquid
fuel
boilers,
and
thus
conclude
that
the
particulate
matter
standard
best
reflects
the
emission
levels
achieved
by
the
relevant
best
performers.
Similar
to
the
above
discussion,
calculating
an
alternative
total
metal
emissions
floor
raises
questions
regarding
the
method
used
to
calculate
such
floors.
Hazardous
waste
combustor
metal
emissions
have
traditionally
been
regulated
in
volatility
groupings
because
the
volatility
of
the
metal
affects
the
efficiency
of
back­
end
control
(
i.
e.,
semivolatile
metals
are
more
difficult
to
control
than
low
volatile
metals
because
they
volatilize
in
the
combustor
and
then
condense
as
small
particulates
prior
to
or
in
the
emission
control
device).
When
identifying
the
best
performing
sources,
we
previously
have,
in
general,
only
evaluated
sources
that
have
metal
emissions
information
for
every
metal
in
the
volatility
grouping.
This
approach
could
prove
to
be
problematic
since
it
is
not
likely
many
sources
will
have
emissions
data
for
all
the
metals.
Although
we
could
not
calculate
alternative
total
metal
emission
floor
standards
based
on
the
available
emissions
data
we
have,
we
agree
with
the
commenters'
view
that
sources
that
burn
hazardous
waste
fuels
with
low
levels
of
nonenumerated
metals
should
be
allowed
to
comply
with
a
metals
standard
rather
than
the
particulate
matter
standard.
We
proposed
an
alternative
to
the
particulate
matter
standard
(
see
69
FR
at
21331)
for
incinerators,
liquid,
and
solid
fuel
boilers
that
was
a
simplified
version
of
the
alternative
particulate
matter
standard
that
is
currently
in
effect
for
incinerators
pursuant
to
the
interim
standards
(
see
§
63.1206(
b)(
14)).
We
received
no
adverse
comment
and
are
promulgating
135
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
3.1.
this
alternative
as
proposed.
The
alternative
metal
standards
apply
to
both
enumerated
and
nonenumerated
metal
HAP,
excluding
mercury.
For
purposes
of
these
alternative
requirements,
each
nonenumerated
metal
is
classified
as
either
a
semivolatile
or
a
low
volatile
metal
and
subsequently
grouped
with
the
associated
semivolatile
and
low
volatile
enumerated
metals.
The
semivolatile
and
low
volatile
metals
standards
under
this
alternative
are
the
same
as
those
that
apply
to
other
liquid
fuel
boilers,
but
the
standard
would
apply
to
all
metal
HAP,
not
just
those
enumerated
in
the
generic
low
volatile
metal
and
semivolatile
metal
standards.
See
§
§
§
63.1216(
e),
63.1217(
e)
and
63.1219(
e).

B.
Carbon
Monoxide/
Hydrocarbons
and
DRE
as
Surrogates
for
Dioxin/
Furan
Comment:
One
commenter
states
that
the
dioxin/
furan
floors
for
new
and
existing
solid
fuel
boilers
is
unlawful
and
arbitrary
and
capricious.
EPA
established
the
floor
for
dioxin/
furan
for
these
sources
as
compliance
with
the
carbon
monoxide
or
hydrocarbon
standard
and
the
destruction
and
removal
efficiency
(
DRE)
standard.
The
commenter
states
that
EPA
has
not
shown
that
carbon
monoxide
or
hydrocarbon
emissions
correlate
to
dioxin/
furan
emissions,
and,
accordingly,
has
not
shown
that
the
carbon
monoxide
or
hydrocarbon
standard,
together
with
the
DRE
standard,
are
valid
surrogates.
This
commenter
also
states
that
it
is
inappropriate
for
EPA
to
use
carbon
monoxide
or
hydrocarbons
and
DRE
as
surrogates
to
establish
dioxin/
furan
floors
for
liquid
fuel
boilers
with
wet
or
no
air
pollution
control
devices
and
for
hydrochloric
acid
production
furnaces.
The
commenter
believes
EPA
inappropriately
justifies
these
surrogates
by
claiming
that
a
numerical
dioxin/
furan
floor
would
not
be
replicable
by
the
best
sources
or
duplicable
by
the
others.
The
commenter
states
that
EPA
has
no
discretion
to
avoid
setting
floors
for
a
HAP
just
because
it
believes
that
HAP
is
not
controlled
with
a
technology.
Rather,
EPA
must
set
floors
reflecting
the
relevant
best
sources'
actual
performance.
Such
floors
necessarily
will
be
duplicable
by
the
relevant
best
sources
themselves.
That
they
cannot
be
replicated
by
other
sources
is
irrelevant
according
to
the
commenter.
In
addition,
the
commenter
states
that
EPA
does
not
claim
or
demonstrate
that
the
carbon
monoxide
and
hydrocarbon
floors
for
solid
fuel
boilers
reflect
the
average
emission
levels
achieved
by
the
relevant
best
sources.
Finally,
the
commenter
also
notes
that
EPA
appears
to
argue
that
its
carbon
monoxide
or
hydrocarbon
standard
and
DRE
standard
could
be
viewed
as
work
practice
standards
under
section
112(
h)
which
allows
EPA
to
establish
work
practice
standards
in
lieu
of
emission
standards
only
if
it
is
not
be
feasible
to
set
the
former.
Because
EPA
has
made
no
such
demonstration,
setting
work
practice
standards
to
control
dioxin/
furan
emissions
from
boilers
would
be
unlawful
according
to
the
commenter.
Response:
The
commenter
raises
four
issues:
(
1)
are
the
carbon
monoxide/
hydrocarbon
standard
and
the
DRE
standard
adequate
surrogate
floors
to
control
dioxin/
furan;
(
2)
floors
for
existing
sources
must
be
established
as
the
average
emission
limitation
achieved
by
the
best
performing
sources
irrespective
of
whether
the
limitation
is
duplicable
by
the
best
performing
sources
or
replicable
by
other
sources;
(
3)
EPA
has
not
explained
how
the
carbon
monoxide
and
hydrocarbon
floors
reflect
the
average
emission
limitation
achieved
by
the
relevant
best
sources;
and
(
4)
EPA
cannot
establish
work
practice
standards
for
dioxin/
furan
under
section
112(
h)
because
it
has
not
demonstrated
that
setting
an
emission
standard
is
infeasible
under
section
112(
h)(
1).
Carbon
Monoxide
and
Hydrocarbons
Are
Adequate
Surrogates
to
Control
Dioxin/
Furan
when
Other
Controls
Are
Not
Effective
or
Achievable.
Carbon
monoxide
and
hydrocarbons
(
coupled
with
the
DRE
standard)
are
the
best
available
surrogates
to
control
dioxin/
furan
emissions
when
a
numerical
floor
would
not
be
achievable
and
when
other
indirect
controls,
such
as
control
of
the
gas
temperature
at
the
inlet
of
a
dry
particulate
matter
control
device
to
400F,
are
not
applicable
or
effective.
136
As
we
explained
at
proposal,
operating
under
good
combustion
conditions
to
minimize
emissions
of
organic
compounds
such
as
polychlorinated
biphenyls,
benzene,
and
phenol
that
can
be
precursors
to
dioxin/
furan
formation
is
an
important
requisite
to
control
dioxin/
furan
emissions.
137
See
69
FR
at
21274.
Minimizing
dioxin/
furan
precursors
by
operating
under
good
combustion
practices
plays
a
part
in
controlling
dioxin/
furan
emissions,
and
that
role
is
substantially
enhanced
when
there
are
no
other
dominant
factors
that
relate
to
dioxin/
furan
formation
and
emission
(
e.
g.,
operating
a
dry
particulate
matter
control
device
at
temperatures
above
400F).
Carbon
monoxide
and
hydrocarbons
are
widely
accepted
indicators
of
combustion
conditions.
The
current
RCRA
regulations
for
boilers
and
hydrochloric
acid
production
furnaces
use
emissions
limits
on
carbon
monoxide
and
hydrocarbons
to
control
emissions
of
toxic
organic
compounds.
See
56
FR
7150
(
February
21,
1991)
documenting
the
relationship
between
carbon
monoxide,
combustion
efficiency,
and
emissions
of
organic
compounds.
In
addition,
carbon
monoxide
and
hydrocarbons
are
used
by
many
CAA
standards
for
combustion
sources
to
control
emissions
of
organic
HAP,
including:
MACT
standards
for
hazardous
waste
burning
incinerators,
hazardous
waste
burning
cement
kilns,
hazardous
waste
burning
lightweight
aggregate
kilns,
Portland
cement
plants,
and
industrial
boilers;
and
section
129
standards
for
commercial
and
industrial
waste
incinerators,
municipal
waste
combustors,
and
medical
waste
incinerators.
Finally,
hydrocarbon
emissions
are
an
indicator
of
organic
hazardous
air
pollutants
because
hydrocarbons
are
a
direct
measure
of
organic
compounds.
Commenters
on
our
proposed
MACT
standards
for
hazardous
waste
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
stated
that
EPA's
own
surrogate
evaluation138
did
not
demonstrate
a
relationship
between
carbon
monoxide
or
hydrocarbons
and
organic
HAP
at
the
carbon
monoxide
and
hydrocarbon
levels
evaluated.
See
64
FR
at
52847
(
September
30,
1999).
Several
commenters
on
that
proposed
rule
noted
that
this
should
not
have
been
a
surprise
given
that
the
carbon
monoxide
and
hydrocarbon
emissions
data
evaluated
were
generally
from
hazardous
waste
combustors
operating
under
good
combustion
conditions
(
and
thus,
relatively
low
carbon
monoxide
and
hydrocarbon
levels).
Under
these
conditions,
emissions
of
HAP
were
generally
low,
which
made
the
136
As
discussed
in
Part
Two,
Section
V,
we
view
the
carbon
monoxide,
hydrocarbon,
and
destruction
removal
efficiency
standards
as
unaffected
by
the
Court's
vacature
of
the
September
1999
challenged
regulations
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
We
are
therefore
not
repromulgating
and
reopening
consideration
of
these
standards
in
today's
final
rule
for
these
source
categories.
137
Operating
under
good
combustion
conditions
also
helps
minimize
soot
formation
on
boiler
tubes.
Research
has
shown
that
operating
under
conditions
that
can
form
soot
followed
by
operating
under
good
combustion
conditions
can
lead
to
dioxin/
furan
formation.
See
Section
2.4
of
Volume
III
of
the
Technical
Support
Document.
138
See
Energy
and
Environmental
Research
Corporation,
``
Surrogate
Evaluation
of
Thermal
Treatment
Systems,''
Draft
Report,
October
17,
1994.
demonstration
of
a
relationship
more
difficult.
These
commenters
noted
that
there
may
be
a
correlation
between
carbon
monoxide
and
hydrocarbons
and
organic
HAP,
but
it
would
be
evident
primarily
when
actual
carbon
monoxide
and
hydrocarbon
levels
are
higher
than
the
regulatory
levels.
We
agreed
with
those
commenters,
and
concluded
that
carbon
monoxide
and
hydrocarbon
levels
higher
than
those
we
established
as
emission
standards
for
hazardous
waste
burning
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
are
indicative
of
poor
combustion
conditions
and
the
potential
for
increased
emissions
organic
HAP.
We
continue
to
believe
that
carbon
monoxide
and
hydrocarbons
are
adequate
surrogates
for
organic
HAP
which
may
be
precursors
for
dioxin/
furan
formation
and
note
that
the
commenter
did
not
explain
why
our
technical
analysis
is
problematic.
Emissions
that
Are
Not
Replicable
or
Duplicable
Are
Not
Being
"
Achieved".
The
commenter
believes
that
floors
must
be
established
as
the
average
emission
limitation
of
the
best
performing
sources
irrespective
of
whether
they
are
replicable
by
the
best
performing
sources
or
duplicable
by
other
sources.
To
the
contrary,
emission
levels
that
are
not
replicable
by
the
best
performing
sources
are
not
being
"
achieved"
by
those
sources
and
cannot
be
used
to
establish
the
floor.
For
solid
fuel
boilers,
we
explained
at
proposal
why
dioxin/
furan
emissions
are
not
replicable
by
the
best
performing
sources
(
or
duplicable
by
other
sources):
there
is
no
dominant,
controllable
means
that
sources
are
using
that
can
control
dioxin/
furan
emissions
to
a
particular
level.
See
69
FR
at
21274­
75.
We
explained
that
data
and
information
lead
us
to
conclude
that
rapid
quench
of
post­
combustion
gas
temperatures
to
below
400
°
F
 
the
control
technique
that
is
the
basis
for
the
MACT
standards
for
dioxin/
furan
for
hazardous
waste
burning
incinerators,
and
cement
and
lightweight
aggregate
kilns
 
is
not
the
dominant
dioxin/
furan
control
mechanism
for
coal­
fired
boilers.
We
believe
that
sulfur
contributed
by
the
coal
fuel
is
a
dominant
control
mechanism
by
inhibiting
formation
of
dioxin/
furan.
Nonetheless,
we
do
not
know
what
minimum
level
of
sulfur
provides
significant
control.
Moreover,
sulfur
in
coal
causes
emissions
of
sulfur
oxides,
a
criteria
pollutant,
and
particulate
sulfates.
For
this
reason,
as
well
as
reasons
stated
at
69
FR
21275,
we
are
not
specifying
a
level
of
sulfur
in
coal
for
these
sources
as
a
means
of
dioxin/
furan
control.
The
same
rationale
applies
to
liquid
fuel
boilers
with
no
air
pollution
controls
or
wet
air
pollution
control
systems
and
to
hydrochloric
acid
production
furnaces­­
there
is
no
dominant,
controllable
means
that
sources
are
using
that
can
control
dioxin/
furan
emissions
to
a
particular
emission
level.
139
Thus,
best
performer
dioxin/
furan
emissions
are
not
replicable
by
the
best
performing
sources
(
or
duplicable
by
other
sources).
For
these
sources,
the
predominant
dioxin/
furan
formation
mechanism
for
other
source
categories
 
operating
a
fabric
filter
or
electrostatic
precipitator
above
400F
 
is
not
a
factor.
Given
that
these
sources
are
not
using
controllable
means
to
control
dioxin/
furan
to
a
particular
emission
level,
there
is
no
assurance
that
the
best
performers
can
achieve
in
the
future
the
emission
level
reported
in
the
compliance
test
in
our
data
base.
Put
another
way,
the
test
data
do
not
reflect
these
sources'
variability,
and
the
variability
is
largely
unquantifiable
given
the
uncertainties
regarding
control
mechanisms
plus
the
environmental
counter­
productiveness
of
encouraging
use
of
higher
sulfur
coal.
Hence,
that
reported
emission
level
is
not
being
"
achieved"
for
the
purpose
of
establishing
a
floor.

139
We
note
that
the
same
rationale
also
applies
to
incinerators
with
wet
or
no
air
pollution
control
equipment
and
that
are
not
equipped
with
a
waste
heat
boiler.
Finally,
we
note
that
beyond­
the­
floor
controls
such
as
activated
carbon
can
control
dioxin/
furan
to
a
particular
emission
level.
If
a
source
were
to
install
activated
carbon,
it
could
achieve
the
level
demonstrated
in
a
compliance
test,
after
adjusting
the
level
to
account
for
emissions
variability
to
ensure
the
measurement
was
replicable.
The
commenter
argues
that
such
a
result
is
mandatory
under
the
straight
emissions
approach
(
the
only
way
the
commenter
believes
best
performers
can
be
determined).
Doing
so,
however,
would
amount
to
a
surreptitious
beyond­
the­
floor
standard
(
forcing
adoption
of
a
control
technology
not
used
by
any
existing
source),
without
considering
the
beyond­
the­
floor
factors
set
out
in
section
112(
d)(
2).
In
fact,
we
considered
beyond­
the­
floor
standards
based
on
use
of
activated
carbon
for
these
sources
 
solid
fuel
boilers,
liquid
fuel
boilers
with
wet
or
no
emission
control
device,
and
hydrochloric
acid
production
furnaces­­
but
rejected
them
for
reasons
of
cost.
The
cost­
effectiveness
ranged
from
$
2.5
million
to
$
4.9
million
per
gram
TEQ
of
dioxin/
furan
removed.
In
contrast,
the
cost­
effectiveness
of
the
beyond­
the­
floor
standard
we
promulgate
for
liquid
fuel
boilers
equipped
with
dry
emission
control
devices
is
$
0.63
million
per
gram
TEQ
of
dioxin/
furan
removed.
140
Consequently,
we
are
not
promulgating
a
beyond­
the­
floor
standard
for
dioxin/
furan
for
these
sources,
and
do
not
believe
we
should
adopt
such
a
standard
under
the
guise
of
determining
floor
levels.
The
Carbon
Monoxide
and
Hydrocarbon
Floors
Are
Appropriate
MACT
Floors.
We
explained
at
proposal
why
the
carbon
monoxide
standard
of
100
ppmv
and
the
hydrocarbon
standard
of
10
ppmv
are
appropriate
floors.
See
69
FR
at
21282.
The
floor
level
for
carbon
monoxide
of
100
ppmv
is
a
currently
enforceable
Federal
standard.
Although
some
sources
are
achieving
carbon
monoxide
levels
below
100
ppmv,
it
is
not
appropriate
to
establish
a
lower
floor
level
because
carbon
monoxide
is
a
conservative
surrogate
for
organic
HAP.
Organic
HAP
emissions
may
or
may
not
be
substantial
at
carbon
monoxide
levels
greater
than
100
ppmv,
and
are
extremely
low
when
sources
operate
under
the
good
combustion
conditions
required
to
achieve
carbon
monoxide
levels
in
the
range
of
zero
to
100
ppmv.
141
(
See
also
the
discussion
below
regarding
the
progression
of
hydrocarbon
oxidation
to
carbon
dioxide
and
water).
As
such,
lowering
the
carbon
monoxide
floor
below
100
ppmv
may
not
provide
significant
reductions
in
organic
HAP
emissions.
Moreover,
it
would
be
inappropriate
to
establish
the
floor
blindly
using
a
mathematical
approach
 
the
average
emissions
for
the
best
performing
sources­­
because
the
best
performing
sources
may
not
be
able
to
replicate
their
emission
levels
(
and
other
sources
may
not
be
able
to
duplicate
those
emission
levels)
using
the
exact
types
of
good
combustion
practices
they
used
during
the
compliance
test
documented
in
our
data
base.
This
is
because
there
are
myriad
factors
that
affect
combustion
efficiency
and,
subsequently,
carbon
monoxide
emissions.
Extremely
low
140
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Sections
12,
13,
and
15.
141
We
note,
however,
that
this
general
principle
may
not
always
apply.
There
are
data
that
indicate
that
even
though
carbon
monoxide
levels
are
below
100
ppmv,
hydrocarbon
levels
may
not
always
be
below
10
ppmv.
See
64
FR
at
52851
and
Part
Four,
Section
IV
B.
and
C.
of
this
preamble.
An
example
of
how
this
might
occur,
although
not
a
likely
practical
scenario,
is
if
combustion
is
quenched
before
substantial
carbon
monoxide
can
be
generated,
leaving
unburned
hydrocarbons
in
the
stack
gas.
Because
of
this
potential
(
although
unlikely)
concern,
the
rule
requires
sources
that
elect
to
monitor
carbon
monoxide
rather
than
hydrocarbons
to
conduct
a
one­
time
test
to
document
that
hydrocarbons
are
below
10
ppmv
and
to
establish
operating
limits
on
parameters
that
affect
combustion
conditions
(
i.
e.,
the
same
operating
parameters
that
we
use
for
compliance
assurance
with
the
DRE
standard).
See
§
63.1206(
b)(
6).
carbon
monoxide
emissions
cannot
be
assured
by
controlling
only
one
or
two
operating
parameters.
We
proposed
a
floor
level
for
hydrocarbons
of
10
ppmv
even
though
the
currently
enforceable
standard
for
boilers
and
hydrochloric
acid
production
furnaces
is
20
ppmv
because:
(
1)
although
very
few
sources
elect
to
comply
with
the
RCRA
standard
for
hydrocarbons
rather
than
the
standard
for
carbon
monoxide,
those
that
comply
with
the
hydrocarbon
standard
have
hydrocarbon
levels
well
below
10
ppmv;
and
(
2)
reducing
hydrocarbon
emissions
within
the
range
of
20
ppmv
to
10
ppmv
may
reduce
emissions
of
organic
HAP.
Although
all
sources
are
likely
to
be
achieving
hydrocarbon
levels
below
10
ppmv,
it
is
not
appropriate
to
establish
a
lower
floor
level
because
hydrocarbons
are
a
surrogate
for
organic
HAP.
Although
total
hydrocarbons
would
be
reduced
at
a
floor
level
below
10
ppmv,
we
do
not
know
whether
organic
HAP
would
be
reduced
substantially.
As
combustion
conditions
improve
and
hydrocarbon
levels
decrease,
the
larger
and
easier
to
combust
compounds
are
oxidized
to
form
smaller
compounds
that
are,
in
turn,
oxidized
to
form
carbon
monoxide
and
water.
As
combustion
continues,
carbon
monoxide
is
then
oxidized
to
form
carbon
dioxide
and
water.
Because
carbon
monoxide
is
a
difficult­
todestroy
refractory
compound
(
i.
e.,
oxidation
of
carbon
monoxide
to
carbon
dioxide
is
the
slowest
and
last
step
in
the
oxidation
of
hydrocarbons),
it
is
a
conservative
surrogate
for
destruction
of
hydrocarbons,
including
organic
HAP,
as
discussed
above.
As
oxidation
progresses
and
hydrocarbon
levels
decrease,
the
larger,
heavier
compounds
are
destroyed
to
form
smaller,
lighter
compounds
until
ideally
all
hydrocarbons
are
oxidized
to
carbon
monoxide
(
and
then
carbon
dioxide)
and
water.
Consequently,
the
relationship
between
total
hydrocarbons
and
organic
HAP
becomes
weaker
as
total
hydrocarbon
levels
decrease
to
form
compounds
that
are
not
organic
HAP,
such
as
methane
and
acetylene.
142
Moreover,
as
discussed
above
for
carbon
monoxide,
it
would
be
inappropriate
to
establish
the
floor
blindly
using
a
mathematical
approach
 
the
average
emissions
for
the
best
performing
sources­­
because
the
best
performing
sources
may
not
be
able
to
replicate
their
emission
levels
(
and
other
sources
may
not
be
able
to
duplicate
those
emission
levels)
using
the
exact
types
of
good
combustion
practices
they
used
during
the
compliance
test
documented
in
our
data
base.
This
is
because
there
are
myriad
factors
that
affect
combustion
efficiency
and,
subsequently,
hydrocarbon
(
and
carbon
monoxide)
emissions.
Extremely
low
hydrocarbon
emissions
cannot
be
assured
by
controlling
only
one
or
two
operating
parameters.
The
Standards
for
CO
and
HC
Are
Not
Work
Practice
Standards..
The
floor
standards
for
CO
or
HC
for
boilers
and
hydrochloric
acid
production
furnaces
are
quantified
emission
limits.
The
standards
consequently
are
not
work
practice
standards
(
even
though
they
represent
levels
showing
good
combustion
control).
CAA
section
302(
k).
EPA's
reference
to
section
112(
h)(
1)
at
proposal
(
69
FR
at
21275)
was
consequently
erroneous.

142
USEPA,
Technical
Support
Document
for
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards
and
Technologies,
July
1999,
Section
12.1.2.
C.
Use
of
Carbon
Monoxide
and
Total
Hydrocarbons
as
Surrogate
for
Non­
Dioxin
Organic
HAP143
Comment:
A
commenter
states
that
neither
the
total
hydrocarbon
nor
carbon
monoxide
standard
alone
provides
adequate
surrogate
control
for
organic
HAP.
Accordingly,
EPA
must
include
standards
for
both.
Hazardous
waste
combustors
could
have
total
hydrocarbon
levels
below
the
standard
during
the
carbon
monoxide
compliance
tests,
but
higher
total
hydrocarbon
levels
at
other
times
during
normal
operation
because
there
are
many
variables
that
can
affect
total
hydrocarbon
emissions,
and
these
will
not
all
be
represented
during
the
carbon
monoxide
compliance
test.
The
commenter
states
that
EPA
is
on
record
stating
that
carbon
monoxide
limits
alone
may
not
by
itself
minimize
organic
emissions
because
products
of
incomplete
combustion
can
result
from
small
pockets
within
the
combustion
zone
where
adequate
time,
temperature,
turbulence
and
oxygen
have
not
been
provided
to
completely
oxidize
these
organics.
The
commenter
also
states
that
EPA
is
on
record
stating
that
total
hydrocarbon
levels
can
exceed
good
combustion
condition
levels
when
carbon
monoxide
levels
are
below
100
ppmv.
Response:
The
final
rule
requires
compliance
with
destruction
and
removal
efficiency
and
carbon
monoxide
or
hydrocarbon
standards
as
surrogates
to
control
nondioxin
organic
HAP
emissions144
from
liquid
fuel
boilers,
solid
fuel
boilers,
and
hydrochloric
acid
production
furnaces.
These
are
effective
and
reliable
surrogates
to
control
organic
HAP.
We
conclude
that
simultaneous
measurement
of
both
total
hydrocarbons
and
carbon
monoxide
with
continuous
emission
monitors
is
not
necessary
because
each
serves
as
a
reliable
surrogate
to
control
organic
HAP
emissions.
The
commenter
has
cited
EPA
preamble
language
that
was
included
in
the
April
19,
1996
proposed
rule
for
hazardous
waste
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
In
that
rule
we
proposed
to
require
compliance
with
both
the
total
hydrocarbon
standard
and
the
carbon
monoxide
standard.
We
requested
comment
on
whether
these
requirements
were
redundant,
and
we
later
requested
comment
on
whether
we
should
allow
sources
to
comply
with
either
the
carbon
monoxide
standard
or
the
total
hydrocarbon
standard.
We
clarified,
however,
that
allowing
sources
to
comply
with
the
carbon
monoxide
standard
would
be
contingent
on
the
source
demonstrating
compliance
with
the
hydrocarbon
standard
during
the
compliance
test.
We
believed
this
was
necessary
because
we
had
limited
data
that
showed
a
source
could
have
total
hydrocarbon
levels
exceeding
10
ppmv
even
though
their
carbon
monoxide
emission
levels
were
below
100
ppmv.
EPA
subsequently
promulgated
this
approach
in
the
September
1999
Final
Rule.
62
FR
52829.
Today's
rule
adopts
the
same
approach
for
liquid
and
solid
fuel
boilers
and
hydrochloric
acid
production
furnaces.
We
again
conclude
that
it
is
not
necessary
to
require
sources
to
verify
compliance
with
both
of
these
standards
on
a
continuous
basis
with
two
separate
continuous
emission
monitors,
given
the
redundancy
of
these
measurement
techniques.
Total
hydrocarbon
emission
measurements
are
a
more
direct
143
As
discussed
in
part
two,
section
V,
we
view
carbon
monoxide,
hydrocarbon,
and
destruction
removal
efficiency
standards
as
unaffected
by
the
Court's
vacature
of
the
September
1999
challenged
regulations
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
We
are
therefore
not
re­
promulgating
and
did
not
reconsider
these
standards
in
today's
final
rule
for
these
source
categories.
144
As
discussed
in
the
previous
section,
these
standards
are
also
used
as
surrogates
to
control
dioxin/
furans
for
hydrochloric
acid
production
furnaces,
solid
fuel­
fired
boilers,
and
liquid
fuel­
fired
boilers
that
are
not
equipped
with
dry
air
pollution
control
devices.
indicator
of
organic
HAP
emissions
than
carbon
monoxide.
Hence,
continuous
compliance
with
this
standard
always
assures
that
organic
HAP
are
well
controlled.
Carbon
monoxide
is
a
conservative
indicator
of
combustion
efficiency
because
it
is
a
product
of
incomplete
combustion
and
because
it
is
a
refractory
compound
that
is
more
thermally
stable
than
hydrocarbons.
The
hydrocarbon
products
of
incomplete
combustion
that
are
simultaneously
formed
during
incomplete,
or
inefficient,
combustion
conditions
can
be
subsequently
oxidized
later
in
the
combustion
process.
In
such
instances
carbon
monoxide
will
likely
still
be
prevalent
in
the
exhaust
gas
even
though
the
products
of
incomplete
combustion
were
later
oxidized.
The
conservative
nature
of
carbon
monoxide
as
an
indicator
of
good
combustion
practices
is
supported
by
our
data.
At
carbon
monoxide
levels
less
than
100
ppmv,
our
data
indicates
that
there
is
no
apparent
relationship
between
carbon
monoxide
and
hydrocarbons
(
other
than
that
hydrocarbon
levels
are
generally
below
10
ppm
when
carbon
monoxide
levels
are
below
100
ppm).
For
example,
a
source
with
a
carbon
monoxide
level
of
1
ppm
is
no
more
likely
to
have
lower
measured
hydrocarbons
than
a
source
achieving
a
carbon
monoxide
emission
level
of
100
ppm.
145
We
consider
the
few
instances
where
the
data
showed
total
hydrocarbon
levels
above
10
ppmv
while
carbon
monoxide
levels
are
below
100
ppmv
to
be
anomalies.
Even
so,
we
have
accounted
for
this
by
requiring
compliance
with
the
hydrocarbon
standard
during
the
compliance
test
if
a
source
elects
to
comply
with
the
carbon
monoxide
standard.
See
§
§
§
63.1216(
a)(
5)(
i),
1217(
a)(
5)(
i),
and
1218(
a)(
5)(
i).
We
disagree
with
the
commenter's
assertion
that
the
total
hydrocarbon
compliance
demonstration
during
the
compliance
test
is
insufficient.
Sources
are
required
to
establish
numerous
operating
requirements
based
on
operating
levels
that
were
demonstrated
during
the
test,
including
minimum
operating
temperature,
maximum
feed
rates,
minimum
combustion
zone
residence
time,
and
operating
requirements
on
the
hazardous
waste
firing
system
that
control
liquid
waste
atomization
efficiency.
Sources
must
comply
with
these
operating
requirements
on
a
continuous
basis.
Compliance
with
these
requirements,
in
addition
to
the
requirements
to
comply
with
the
carbon
monoxide
and
destruction
and
removal
standards,
adequately
assure
sources
are
controlling
organic
HAP
emissions
to
MACT
levels.
Comment:
A
commenter
states
that
EPA's
proposed
use
of
surrogates
for
organic
HAP
do
not
ensure
that
each
of
the
organic
HAP
(
e.
g.,
polychlorinated
biphenyls
and
polyaromatic
hydrocarbons)
are
reduced
to
the
level
of
the
HAP
emitted
by
the
relevant
best
performing
sources.
EPA
has
not
shown
the
necessary
correlation
between
either
the
total
hydrocarbon
or
carbon
monoxide
standards
and
organic
HAP,
and
neither
is
a
reasonable
surrogate
according
to
the
commenter.
Response:
Carbon
monoxide
and
total
hydrocarbon
monitoring
are
widely
used
and
accepted
indicators
of
combustion
efficiency,
and
hence
control
organic
HAP,
which
are
destroyed
by
combustion.
146
Sources
that
are
achieving
carbon
monoxide
of
emission
levels
of
100
ppm
or
a
hydrocarbon
emission
levels
of
10
ppm
are
known
to
be
operating
145
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
3.2
and
USEPA,
"
Final
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards
and
Technologies,"
July
1999,
Section
5.1.
146
This
is
why
almost
all
of
the
RCRA
Land
Disposal
Restiction
treatment
standards
for
organic
waste,
which
standards
are
for
the
most
part
established
at
an
analytic
detection
level
for
the
organic
HAP
in
question
plus
a
variability
factor,
are
based
on
the
performance
of
combustion
technology.
See
40
CFR
Part
268.40­
43.
pursuant
to
good
combustion
practices.
This
is
supported
by
an
extensive
data
analysis
we
used
to
support
identical
standards
for
incinerators,
cement
kilns,
and
lightweight
kilns
which
were
promulgated
in
the
September
1999
Final
Rule.
We
are
applying
the
same
rationale
to
support
these
standards
for
boilers
and
hydrochloric
acid
production
furnaces.
Today's
rule
requires
continuous
compliance
with
either
a
carbon
monoxide
and
hydrocarbon
standard,
in
combination
with
a
destruction
and
removal
efficiency
standard,
as
surrogates
to
control
organic
HAP.
We
conclude
that
sources
which
comply
with
these
standards
are
operating
under
efficient
combustion
conditions,
assuring
non­
dioxin
organic
HAP
are
being
oxidized,
thus
limiting
emissions
to
levels
reflecting
MACT.
Efficient
combustion
of
hazardous
waste
minimizes
emissions
of
organic
HAP
that
are
fed
to
the
combustion
chamber
as
well
as
emissions
attributable
to
products
of
incomplete
combustion
that
may
form
within
the
combustion
chamber
or
post
combustion.
We
are
not
capable
of
issuing
emission
standards
for
each
organic
HAP
because
of
data
limitations
and
because
such
emission
standards
may
not
be
replicable
by
individual
sources
or
duplicable
by
the
other
best
performing
sources
because
of
the
complex
nature
of
combustion
and
post
combustion
formation
of
products
of
incomplete
combustion.

V.
Additional
Issues
Relating
to
Variability
and
Statistics
Many
commenters
raised
issues
relating
to
emissions
variability
and
statistics
other
than
those
discussed
above
in
Section
III.
A:
(
1)
variability
dampening
for
data
sets
containing
nondetects;
(
2)
imputation
of
variability
to
address
variability
dampening
for
data
sets
containing
nondetects;
and
(
3)
our
analysis
of
variance
procedures
to
identify
subcategories.
We
present
comments
and
responses
on
the
remaining
topics
below.

A.
Data
Sets
Containing
Nondetects
Comment:
One
commenter
states
that
EPA's
approach
of
assuming
measurements
that
are
below
detection
limits
are
present
at
the
detection
limit
dampens
the
variability
of
the
data
set.
Thus,
the
variability
of
ranking
parameters
is
understated
when
ranking
sources
to
identify
the
best
performers
and
emissions
variability
is
understated
when
calculating
the
floor.
Response:
We
agree
with
the
commenter.
For
the
final
rule,
we
use
an
approach
to
address
nondetects
whereby
a
value
is
assigned
to
each
nondetect
within
its
possible
range
such
that
the
99th
percentile
upper
prediction
limit
for
the
data
set
(
i.
e.,
test
condition
runs
for
each
source)
is
maximized.
Although
this
approach
maximizes
the
deviation
among
runs
containing
nondetect
measurements,
the
test
condition
average
is
lower
because
we
no
longer
assume
the
nondetect
analyte
is
present
at
the
level
of
detection.
See
response
to
comments
discussion
below
for
more
information
on
this
statistical
approach
to
address
variability
of
nondetects.
We
use
this
measurement
imputation
approach
to
address
variability
of
feedrate
data
sets
containing
nondetects
for
source
ranking
purposes
and
to
address
variability
of
emissions
data
sets
containing
nondetects
when
calculating
floors.
We
do
not
apply
the
measurement
implementation
approach
to
system
removal
efficiency
(
SRE)
data
sets
where
feedrates
or
emissions
contain
nondetects,
however.
Statistical
imputation
of
nondetect
SREs
is
complicated
given
that
SRE
is
derived
from
feedrate
and
emissions
data,
both
of
which
could
contain
nondetect
measurements.
147
Our
inability
to
apply
the
imputation
approach
to
SREs
is
not
a
major
concern,
however,
because
system
removal
efficiency
is
used
as
a
source
ranking
criterion
only
(
i.
e.,
it
is
not
used
as
the
standard,
except
for
hydrochloric
acid
production
furnaces
where
there
are
no
nondetect
feedrate
or
emissions
measurements),
and
there
are
few
instances
where
system
removal
efficiencies
are
derived
from
nondetect
feedrate
or
emissions
data.

B.
Using
Statistical
Imputation
to
Address
Variability
of
Nondetect
Values
On
February
4,
2005,
EPA
distributed
by
email
to
major
commenters
on
the
proposed
rule
a
direct
request
for
comments
on
a
limited
number
of
issues
that
were
raised
by
the
public
comments
on
the
proposed
rule.
The
nondetect
measurement
imputation
approach
discussed
above
was
one
of
the
issues
for
which
we
requested
comment.
We
discuss
below
the
major
comments
on
the
approach.
Comment:
Most
commenters
state
that
they
agree
with
either
the
concept
or
the
approach
in
principle
but
cannot
provide
substantive
comments.
These
commenters
indicate
they
cannot
provide
substantive
comments
because
they
cannot
determine
the
implications
of
using
the
approach
given
that
we
did
not
provide
the
resulting
floor
calculations.
One
commenter
suggests
that,
before
blindly
applying
this
arbitrary
estimate
of
a
nondetect
value,
a
reality
check
should
be
done
to
validate
that
this
is
reasonable
by
consulting
what
is
published
on
the
method
variability,
as
well
as
by
checking
variability
factors
derived
for
other
data
in
the
database
that
are
above
the
detection
limit.
Another
commenter
voiced
significant
concerns
with
the
approach.
The
commenter
states
that
EPA
contradicts
its
assumption
at
proposal
that
all
data
that
are
reported
as
nondetect
are
present
at
the
detection
limits
by
now
admitting
that
the
true
value
is
between
zero
and
the
level
of
detection.
The
commenter
concludes
that
EPA
now
proposes
to
retreat
from
its
assumption
that
undetected
pollutants
are
always
present
at
the
detection
limits
not
because
that
assumption
is
false
but
because
it
does
not
generate
sufficiently
lenient
floors.
The
commenter
believes
that
this
underscores
that
EPA's
statistical
analysis
approach
cannot
possibly
give
an
accurate
picture
of
any
source's
actual
emission
levels.
Accordingly,
it
cannot
possibly
satisfy
EPA's
obligation
to
ensure
that
its
floors
reflect
the
average
emission
levels
achieved
by
the
relevant
best
performing
sources.
The
commenter
also
states
that
EPA's
imputation
approach
is
independently
flawed
because
it
assumes­­
again
inaccurately­­
that
the
value
for
a
nondetect
is
always
either
the
highest
value
or
lowest
value
in
the
allowable
range.
In
reality
the
undetected
values
will
necessarily
fall
in
a
range
between
the
highest
and
lowest,
and
thus
yield
less
variability
than
EPA
would
assume.
Response:
We
agree
in
theory
with
the
commenter
who
suggests
that
the
results
of
the
imputation
approach
should
be
checked
to
see
if
it
overstates
variability
for
nondetect
data
by
comparing
the
results
of
the
imputation
approach
with
the
actual
variability
for
detected
measurements
in
the
data
set.
We
considered
comparing
the
relative
standard
deviation
derived
from
the
imputation
approach
for
data
sets
with
nondetects,
to
the
relative
standard
deviation
for
the
data
set
using
a
regression
analysis.
Under
the
regression
analysis
approach,
we
considered
relating
the
relative
standard
deviation
of
detected
data
sets
to
the
147
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005
Section
7.3.
average
measurement.
We
would
determine
this
relationship
for
each
standard
for
which
we
have
nondetect
data,
and
use
the
relationship
to
impute
the
standard
deviation
for
a
data
set
containing
nondetects.
148
We
could
not
perform
this
analysis,
however,
because:
(
1)
we
have
very
few
detected
measurements
for
the
data
sets
for
several
standards
and
could
not
establish
the
relationship
between
relative
standard
deviation
and
emission
concentration
for
those
data
sets;
and
(
2)
moreover,
for
many
data
sets
where
detected
measurements
would
have
been
adequate
to
establish
the
relationship,
it
would
have
been
problematic
statistically
to
extrapolate
the
relationship
to
the
very
low
values
assigned
to
the
nondetect
measurements
(
e.
g.,
100%
of
the
detection
limit;
the
value
assigned
by
our
statistical
imputation
approach).
149
This
commenter
also
suggests
that
we
check
the
resultant
standard
deviation
after
imputation
by
consulting
what
is
published
on
the
method
variability.
The
commenter
did
not
explain,
however,
how
method
variability
relates
to
the
variability
of
nondetect
data.
Moreover,
we
believe
that
the
imputation
approach
is
one
approach
we
could
have
reasonably
used
to
estimate
variability
of
nondetect
data.
We
first
attempted
to
apply
standard
statistical
techniques
to
address
the
nondetect
issue.
We
investigated
standard
interval
censoring
techniques
to
calculate
maximum
likelihood
estimates
(
MLE)
of
the
average
and
standard
deviation
that
provide
the
best
fit
for
a
normal
distribution
for
the
data
containing
nondetect
values,
taking
into
account
that
each
nondetect
data
point
can
be
anywhere
within
its
allowable
interval.
These
techniques
are
not
applicable,
however,
to
data
sets
where
all
data
are
nondetects,
as
is
the
case
for
many
of
our
data
sets.
In
that
situation,
we
approximated
the
mean
as
the
average
of
the
midpoints
of
the
nondetect
intervals,
and
the
standard
deviation
as
one
half
of
the
possible
range
of
the
data.
After
working
with
this
MLE/
Approximation
approach
for
some
time
and
iteratively
developing
complicated
algorithms
to
address
problems
as
they
arose,
we
concluded
that
we
needed
a
simpler
approach
that
could
be
applied
to
all
data
sets.
Accordingly,
we
developed
the
statistical
imputation
approach
discussed
in
Section
IV.
A
above.
For
22
separate
floors,
we
compared
the
results
of
the
approaches
we
considered
for
nondetects:
(
1)
nondetects
present
at
the
detection
limit
(
i.
e.,
full
detection
limit
approach);
(
2)
MLE;
(
3)
MLE
combined
with
an
approximation
approach
(
i.
e.,
MLE/
Approximation
approach;
and
(
4)
statistical
imputation.
150
The
MLE
approach
was
only
applicable
to
2
of
the
22
floor
data
sets,
and
the
numerical
algorithm
failed
to
converge
on
an
answer
for
one
of
those.
The
MLE/
Approximation
approach
sometimes
results
in
floors
that
are
unrealistically
high
(
i.
e.,
it
calculated
5
of
22
floors
that
were
higher
than
the
statistical
imputation
approach,
which
always
produces
floors
that
are
equal
to
or
higher
than
assuming
nondetects
are
present
at
the
full
detection
limit),
and
sometimes
fails
to
converge
on
an
answer.
Because
of
these
limitations,
we
do
not
use
either
the
MLE
or
MLE/
Approximation
approach.

148
Note
that,
under
this
approach,
we
would
continue
to
assume
that
the
nondetect
analyte
is
present
at
the
detection
limit.
149
Note
that
this
was
not
the
case
where
we
use
a
regression
analysis
of
relative
standard
deviation
versus
total
chlorine
measurements
to
impute
a
standard
deviation
for
values
below
20
ppmv
that
we
corrected
to
20
ppmv
to
address
the
low
bias
of
Method
0050.
In
that
situation,
we
have
several
total
chlorine
measurements
very
close
to
20
ppmv.
150
See
USEPA,
"
Technical
Support
Document
for
the
HWC
MACT
Standards,
Volume
III:
Selection
of
MACT
Standards,"
September
2005,
Section
5.4.
We
believe
the
statistical
imputation
approach
is
preferable
to
the
full
detection
limit
approach
because
it:
(
1)
accounts
for
variability
of
data
sets
containing
nondetects;
(
2)
can
be
applied
to
all
data
sets
containing
nondetects;
and
(
3)
results
in
reasonable
floor
levels.
In
most
cases,
floors
calculated
using
statistical
imputation
are
close
to
those
calculated
by
the
full
detection
limit
approach.
The
statistical
imputation
approach
can
produce
substantially
higher
floors
than
the
full
detection
limit
approach,
however,
when
a
relatively
high
nondetect
is
reported
because
of
a
high
detection
limit.
Nonetheless,
the
statistical
imputation
approach
calculated
floors
that
were
30%
higher
than
the
full
detection
limit
approach
for
only
2
of
the
22
floors.
We
reject
the
comment
that
our
approach
to
handling
nondetect
data
is
a
mere
manipulation
to
raise
the
floor.
The
commenter
observes
that
EPA
appears
to
determine
that
its
initial
approach
of
assuming
the
worst­
case
for
nondetect
data
 
that
the
data
are
present
at
the
detection
limit
 
did
not
produce
floors
that
were
high
enough,
and
consequently
applies
another
manipulation
 
statistical
imputation
of
nondetect
measurements
 
that
assumes
the
nondetect
data
are
present
at
lower
levels
but
nonetheless
generates
floors
that
are
even
higher
than
before.
Although
the
commenter
is
correct
about
the
outcome
of
our
handling
of
nondetect
data
 
the
floors
are
generally
higher
after
statistically
imputing
nondetect
measurements
than
if
nondetects
are
simply
assumed
to
be
present
at
the
detection
limit
 
our
rationale
for
handling
nondetects
is
sound.
At
proposal,
we
assumed
that
nondetects
are
present
at
the
detection
limit.
We
do
not
know
(
nor
does
anyone
else)
whether
a
nondetect
value
is
actually
present
at
1%
or
99%
of
the
detection
limit.
We
thought
that
assuming
that
all
values
were
at
the
limit
of
detection
would
reasonably
estimate
the
range
of
performance
a
source
could
experience
for
these
nondetect
measurements.
This
approach
inherently
maximizes
the
average
emissions
but
minimizes
emissions
variability.
Commenters
on
the
proposed
rule
state
that
assuming
nondetects
are
present
at
the
detection
limit
dampens
emissions
variability
 
a
consideration
necessary
to
ensure
that
a
source's
performance
over
time
is
estimated
reasonably.
Mossville,
370
F.
3d
at
1242
(
daily
maximum
variability
must
be
accounted
for
in
MACT
standards
[
including
floors]
which
must
be
achieved
continuously).
See
also
CMA,
870
F.
2d
at
232
(
EPA
not
even
obligated
to
use
data
from
plants
that
consistently
reported
nondetected
values
in
calculating
variability
factors
for
best
performing
plants).
We
agree
with
these
commenters,
and
are
using
the
statistical
imputation
approach
to
address
the
concern.
Relative
to
our
proposed
approach
of
assuming
nondetect
measurements
are
present
at
the
detection
limit,
the
statistical
imputation
approach
reduces
the
average
of
the
data
set
for
a
source
while
maximizing
the
deviation
of
the
data
set.
These
are
competing
and
somewhat
offsetting
factors
when
calculating
the
floor
for
existing
sources
given
that
we
use
a
modified
99th
percentile
upper
prediction
limit
to
calculate
the
floor
 
the
floor
is
the
average
of
the
test
condition
averages
for
the
best
performers
plus
the
pooled
variance
of
their
runs.
See
CMA,
870
F.
2d
at
232
(
upholding
approach
to
variability
for
datasets
with
nondetect
values
where
various
conservative
assumptions
in
methodology
offset
less
conservative
assumptions).
We
further
disagree
with
this
commenter's
view
that
the
statistical
imputation
approach
is
independently
flawed
because
it
assumes
that
the
value
for
a
nondetect
is
always
either
the
highest
value
or
lowest
value
in
the
allowable
range.
The
commenter
states
that,
in
reality,
the
undetected
values
will
necessarily
fall
in
a
range
between
the
highest
and
lowest,
and
thus
yield
less
variability
than
EPA
would
assume.
Although
the
commenter
is
correct
that
the
true
value
of
a
nondetect
measurement
is
likely
to
be
in
the
range
between
the
highest
or
lowest
value
possible
rather
than
at
either
extreme,
we
do
not
know
where
the
true
value
is
within
that
range.
To
ensure
that
variability
is
adequately
considered
in
establishing
a
floor,
the
statistical
imputation
approach,
by
design,
maximizes
the
deviation
by
assuming
the
nondetect
value
is
at
one
end
of
the
range
or
the
other,
whichever
results
in
a
higher
average
for
the
data
set.
