RESPONSE
TO
OMB
ISSUES
Hazardous
Waste
Combustion
MACT
3­
22­
04
Note
to
reader
­
this
document
was
submittted
to
OMB
on
3­
22­
04,
and
was
intended
to
summarize
and
respond
to
various
issues/
comments
that
were
raised
by
OMB.
Please
note
that
the
summary
of
OMB
concerns
in
this
document
reflect
EPA's
attempt
to
characterize
OMB's
comments
that
were
communicated
to
EPA
verbally
­
they
do
not
necessarily
represent
an
exact
characterization
of
OMB's
concerns
and
or
comments,
nor
were
these
characterizations
verified
by
OMB
to
be
accurate
and
complete.

A.
Beyond
the
Floor
Standards:

EPA
Proposal:

Dioxin/
Furan
beyond­
the­
floor
standards
for
lightweight
aggregate
kilns,
liquid
fuel
boilers,
and
hydrochloric
acid
production
furnaces
Particulate
matter
beyond­
the­
floor
standard
for
coal­
fired
boilers
Total
chlorine
(
HCl/
Cl
2)
beyond­
the­
floor
standards
for
coal­
fired
boilers
and
lightweight
aggregate
kilns
OMB
Recommendation:

Do
not
propose
beyond­
the­
floor
standards
because
they
are
not
cost­
effective.

Total
chlorine
beyond­
the­
floor
standards
are
inconsistent
w/
allowing
risk­
based
limits
under
112d4
that
would
supersede
the
MACT
standards
Total
chlorine
(
hydrogen
chloride
and
chlorine
gas)
is
not
a
particularly
hazardous
pollutant.

EPA
should
also
openly
discuss,
and
request
comment
on,
the
criteria
used
to
determine
if
beyond­
the­
floor
standards
are
warranted
EPA
Response:

1.
We
will
not
propose
beyond­
the­
floor
chlorine
standards
for
coal­
fired
boilers
and
lightweight
aggregate
kilns
given:
1)
the
chlorine
cost­
effectiveness
numbers
are
in
the
"
grey
area"
of
where
EPA
has
previously
determined
as
cost
effective;
and
2)
we
believe
most
of
the
coal­
fired
boilers
and
lightweight
aggregate
kilns
will
qualify
for
the
risk­
based
emission
limits
pursuant
to
112d4.

2.
We
maintain
our
position
that
beyond­
the­
floor
standards
for
dioxin/
furan
and
1
Emission
levels
could
actually
be
higher
at
the
Floor
because
the
Floor
standard
would
not
be
a
numerical
emission
limit
on
dioxin/
furan.
Rather,
the
Floor
standard
would
be
compliance
with
temperature
controls
at
the
air
pollution
control
device
and/
or
operating
under
good
combustion
conditions.
The
Floor
emission
levels
shown
are
the
highest
emissions
data
for
sources
obtained
during
a
"
snap­
shot"
of
their
operations.

2
particulate
matter
are
warranted.

a.
Beyond­
the­
Floor
Dioxin/
Furan
Standards
for
Lightweight
Aggregate
Kilns,
Liquid
Fuel
Boilers,
and
Hydrochloric
Acid
Production
Furnaces
Beyond­
the­
floor
standards
would
reduce
very
high
emissions
at
the
Floor­­
3.0­
6.8
ng
TEQ/
dscm1
 
to
0.4
ng
TEQ/
dscm,
consistent
with
historically
controlled
levels
for
hazardous
waste
incinerators
and
cement
kilns,
and
Portland
cement
plants.

EPA
has
determined
previously
(
in
the
1999
Hazardous
Waste
Combustor
MACT
final
rule)
that
dioxin/
furan
in
the
range
of
0.40
ng
TEQ/
dscm
or
less
are
necessary
for
the
MACT
standards
to
be
considered
generally
protective
of
human
health
under
RCRA
(
using
the
1985
cancer
slope
factor),
thereby
eliminating
the
need
for
separate
RCRA
standards.

Beyond­
the­
floor
dioxin/
furan
standards
are
cost
effective
at
$
830,000
to
$
1,300,000/
gram
TEQ,
considering
the
toxicity
of
dioxin/
furans.

EPA
has
previously
concluded
that
a
relatively
high
cost­
effectiveness
value
is
warranted
for
particularly
problematic
HAP.
In
the
Chlorine
Production
MACT
NPRM,
EPA
determined
that
$
18,000,000/
ton
is
cost­
effective
for
mercury.

Low
incremental
costs:
$
3.6
million
annually
(
market­
adjusted)
to
remove
4.3
gram
TEQ/
yr
using
activated
carbon
injection
for
all
3
beyond­
the­
floor
standards
for
a
rule
that
would
cost
between
$
41­$
56
million
(
depending
on
whether
the
total
chlorine
standard
is
waived
under
112(
d)(
4)).

Nondiscounted
health
benefits
of
$
340,000/
yr
($
33,000/
yr
discounted
at
7%)
using
the
1985
cancer
slope
factor.
There
are
also
health
benefits
other
than
reductions
in
cancer
incidence
that
cannot
be
monetized.

b.
Beyond­
the­
Floor
Particulate
Matter
Standard
for
Coal­
Fired
Boilers
Beyond­
the­
floor
standard
would
reduce
very
high
emissions
at
the
Floor­­
0.060
gr/
dscf
to
0.030
gr/
dscf,
similar
to
the
standard
(
0.034
gr/
dscf)
for
coal­
fired
industrial
boilers
that
do
not
burn
hazardous
waste.
3
Particulate
matter
standards
should
be
similar
because
HW
burning
does
not
affect
particulate
matter
emissions.

Beyond­
the­
Floor
particulate
matter
standard
is
cost­
effective
at
$
87,000/
ton
metal
HAP
(
and
at
$
3,600/
ton
of
particulate
matter
removed).

Low
incremental
cost
of
$
880,000
annually
(
market­
adjusted)
to
improve
the
design,
operation,
and
maintenance
of
existing
electrostatic
precipitators
and
fabric
filters
to
remove
15
tons
per
year
of
metal
hazardous
air
pollutant
Nondiscounted
health
benefits
of
$
74,000/
yr
3.
We
will
revise
the
preamble
and
openly
discuss,
and
request
comment
on,
the
criteria
used
to
determine
if
beyond­
the­
floor
standards
are
warranted.

B.
Response
to
Cement
Kiln
Recycling
Coalition
Petition
for
Rulemaking
Regarding
Site­
Specific
Risk
Assessment
Proposal:
Requests
comment
on
our
tentative
decision
regarding
the
February
28,
2002
petition
for
rulemaking
submitted
by
the
Cement
Kiln
Recycling
Coalition
(
CKRC)
to
the
Administrator.

We
are
proposing
to
partially
deny
CKRC's
request
that
we
repeal
the
Site
Specific
Risk
Assessment
(
SSRA)
policy
and
guidance
because
we
believe
that
there
may
be
situations
where
permitting
authorities
find
that
compliance
with
the
MACT
standards
alone
may
not
be
sufficiently
protective.

We
are
also
proposing
to
partially
grant
CKRC's
request
by
codifying
our
explicit
authority
to
require
SSRAs
on
a
site­
specific
basis
using
notice
and
comment
rulemaking
procedures,
since
we
agree
with
CKRC
that
it
would
be
appropriate
to
codify
the
authority
to
require
SSRAs
and
SSRA­
based
permit
conditions
for
the
sake
of
regulatory
clarity
and
transparency.
We
are
requesting
comment
on
our
tentative
decision.

OMB
Request:
Do
not
propose
regulatory
language
that
codifies
the
authority.
EPA
should
only
request
comment
as
to
whether
codifying
the
authority
is
necessary.

EPA
Response:
We
maintain
that
our
approach
in
the
proposal
to
codify
the
authority
is
appropriate
for
the
following
reasons:

Shortly
after
receiving
CKRC's
February
28,
2002
petition,
we
conducted
a
preliminary
evaluation
of
the
concerns
CKRC
presented.
Based
upon
our
evaluation,
we
realized
that
we
would
need
to
conduct
further
research
(
i.
e.,
gather
and
analyze
data)
and
that
any
decision
regarding
the
petition
ultimately
should
be
made
in
coordination
with
the
Phase
I
4
MACT
Replacement
Standards
and
Phase
II
MACT
Standards
proposed
rulemaking.
We
made
our
intentions
available
(
to
the
public)
via
OMB's
2002
"
Thompson
Report."
Given
our
commitment
to
provide
a
response
in
the
proposed
MACT
rulemaking,
we
do
not
feel
it
is
possible
to
defer
our
response
beyond
the
proposed
rulemaking's
promulgation.
Under
section
7004,
EPA
must
initially
issue
a
draft
petition
response
and
solicit
public
comment;
we
would
be
concerned
that
merely
soliciting
comment
on
whether
to
codify
the
authority
would
raise
questions
about
whether
the
Agency
had
met
that
requirement,
and/
or
potentially
further
delay
our
final
response.

In
addition
to
our
commitment
to
provide
a
response
in
the
proposed
MACT
rulemaking,
there
are
a
couple
of
reasons
why
we
believe
it
important
to
retain
the
proposal
codifying
an
explicit
authority
to
evaluate
the
need
for,
and
potentially
require
an
SSRA
on
a
sitespecific
basis.
The
first
is
to
address
CKRC's
assertion
that
EPA
consistently
relies
upon
RCRA's
omnibus
authority
(
Section
3005(
c)(
3))
to
implement
the
hazardous
waste
combustion
program.
While
we
disagree
that
EPA
has
done
this,
by
codifying
the
authority
in
the
regulations
pursuant
to
sections
3004(
a)
and
3005(
b),
we
are
removing
CKRC's
ability
to
argue
that
EPA
is
improperly
attempting
to
avoid
rulemaking
in
implementing
this
program.
Also,
we
feel
that
the
proposal
does
not
impose
any
new
substantive
requirements
on
the
regulated
community,
but
primarily
serves
a
procedural
function.
The
proposed
language
would
provide
notice
to
the
regulated
community
that
an
SSRA
may
be
necessary
to
support
their
permit,
and
serves
to
remind
the
permitting
agencies
of
the
need
to
evaluate
whether
an
SSRA
would
be
necessary
on
a
site­
specific
basis.

C.
Request
for
Comment
on
Whether
Health
Threshold
Values
Help
Provide
An
Ample
Margin
of
Safety
OMB
Request:
In
the
112(
d)(
4)
discussion
of
whether
the
proposed
approach
ensures
an
ample
margin
of
safety,
request
comment
on
whether
the
conservatism
inherent
in
the
health
threshold
values
(
i.
e.,
RfCs
and
AEGL­
1
values)
helps
ensure
an
ample
margin
of
safety.

EPA
Response:
This
issue
was
raised
in
the
discussions
surrounding
the
industrial
boiler
rule
112(
d)
(
4)
discussion
and
was
not
agreed
to
by
EPA.
We
will
follow
the
templet
used
in
the
industrial
boiler
MACT
rule
(
where
we
did
not
solicit
comment
on
this
issue).

D.
Section
112(
d)(
4):
Acidification
of
Acid­
Sensitive
Surface
Waters
EPA
Proposal:
Requests
comment
on
whether
and
how
to
consider
acidification
of
acidsensitive
surface
waters
as
a
criterion
for
eligibility
for
section
112(
d)(
4)
limits.
5
OMB
Recommendation:
Do
not
request
comment
on
this
issue
because
a
surface
water
acidification
criteria
would
be
inconsistent
with
the
Industrial
Boiler
rule.

EPA
Response:
We
will
follow
the
templet
used
in
the
industrial
boiler
MACT
rule
(
where
we
did
not
solicit
comment
on
this
issue).

E.
Differences
Between
Section
112(
d)(
4)
Provisions
in
Hazardous
Waste
Combustor
Proposal
Vs
Industrial
Boiler
Rule
OMB
Request:
Provide
a
summary
of
the
differences
in
the
section
112(
d)(
4)
provisions
between
the
hazardous
waste
combustor
proposal
and
the
industrial
boiler
rule
EPA
Response:
Summary
table
is
attached
(
see
next
page).
Note
this
table
reflects
the
differences
between
the
hazardous
waste
combustor
MACT
112d4
preamble
previously
sent
to
OMB
and
the
Industrial
Boiler
MACT
Final
Rule.
We
have
subsequently
revised
the
112d4
writeup,
and
have
included
the
revised
writeup
with
this
response.
Sections
of
the
older
writeup
that
were
inconsistent
with
the
Industrial
Boiler
MACT
rule
and
that
have
been
subsequently
revised
are
noted
in
the
table
below
in
the
comments
section
F.
Dioxin
Toxicity
Slope
Factor
OMB
Request:
Benefits
analyses
should
be
based
on
using
the
slope
factor
that
is
consistent
with
other
Agency
regulatory
actions.

EPA
Response:
We
will
display
dioxin/
furan
benefits
that
are
only
associated
with
the
1985
slope
factor,
and
will
revise
the
Addendum
and
economics
part
of
the
Preamble
accordingly.
2
Note
that
there
are,
inadvertently,
two
Section
F's.
6
SUBSTANTIVE
DIFFERENCES
IN
SECTION
112(
D)(
4)
PROVISIONS
BETWEEN
THE
HWC
NPRM
AND
THE
INDUSTRIAL
BOILER
RULE
3­
22­
04
[
Note­
this
table
reflects
the
differences
between
the
hazardous
waste
combustor
MACT
112d4
writeup
previously
sent
to
OMB
and
the
Industrial
Boiler
MACT
Final
Rule.
We
have
subsequently
revised
the
112d4
writeup,
and
have
included
the
revised
writeup
with
this
response.
Sections
of
the
older
writeup
that
were
inconsistent
with
the
Industrial
Boiler
MACT
rule
and
that
have
been
subsequently
revised
are
noted
in
the
table
below
in
the
comments
section.]

Provision
HWC
MACT
NPRM
Industrial
Boiler
Rule
Comment
1.
Acidification
of
Surface
Waters
Requests
comment
on
whether
and
how
to
consider
acidification
as
an
eligibility
criterion
for
112(
d)(
4)..
Section
B.
7
of
the
112(
d)(
4)
­
preamble
discussion.
Acidification
is
not
an
eligibility
criterion
for
112(
d)(
4)
limits.
As
previously
discussed,
this
section
has
been
removed.

2.
Approval
of
Eligibility
Demonstrations
Required.
Section
F
Demonstrations
must
be
submitted,
but
approval
not
explicitly
required
Approval
appropriate
for
HWCs
b/
c
HCl/
Cl2
emissions
are
higher
and
could
approach
an
HI
of
1.0
3.
Consideration
of
Photolysis
of
Cl2
to
HCl
Cannot
consider
photolysis.
Section
B.
1
Look­
up
table
analysis
does
not
consider
photolysis
Site­
specific
analysis
procedure
silent
on
photolysis
Photolysis
should
not
be
considered
b/
c
there
is
generally
insufficient
time
for
the
plume
to
undergoe
significant
transformation
prior
to
reaching
ground­
level
receptors.
Also,

transformation
possible
only
a
portion
of
the
time.

4.
Acute
Exposure
Not
addressed
when
establishing
emission
limit.
Section
B.
2.
e.

Addressed
when
establishing
a
short­
term
chlorine
feedrate
limit
as
a
compliance
parameter.
Section
F.
12
Not
addressed
when
establishing
emission
limit
Silent
on
whether
to
address
when
establishing
operating
limits
Short­
term
feedrate
limit
needed
to
ensure
that
1­
hour
avg
emissions
do
not
exceed
an
HI
of
1.0
for
acute
exposure
(
AEGL­
1
values)

even
though
the
chronic
exposure­
based
annual
average
emission
limit
is
not
exceeded.

This
short
term
limit
may
be
necessary
for
hazardous
waste
combustors
because
some
hazardous
wastes
contain
very
high
chlorine
levels.
7
5.
Exposure
to
other
HAP
that
Have
a
Common
Mechanism
of
Action
Explains
that
the
Agency
needs
to
consider
the
issue
but
that
HAP
other
than
HCl
and
Cl2
would
not
contribute
significantly
to
the
HI
and
thus
would
not
be
considered
when
establishing
emission
limits.
Sections
B.
2.
b
and
B.
2.
c
Sources
do
not
consider
other
HAP
when
establishing
emission
limits.
Approaches
are
the
same.
HWC
MACT
explains
the
rationale
given
that
it
is
a
proposed
rule.

6.
How
to
Ensure
Ample
Margin
of
Safety
Explains
that
consideration
of
costs,

feasibility,
and
other
relevant
factors
in
addition
to
health
not
necessary
to
ensure
AMS.
Section
B.
3
No
discussion
of
this
issue.
Discussion
appropriate
b/
c
it
could
be
argued
otherwise
that
a
section
112(
d)(
4)
limit
could
be
no
less
stringent
than
a
beyond­
the­
floor
standard
(
which
is
by
definition
costeffective

7.
RCRA
Risk
Assessments
Explains
that
RCRA
risk
assessments
would
be
used
to
ensure
RCRA
permit
limits
are
protective
of
human
health
and
the
environment.
Section
B.
4
Not
relevant.
As
previously
discussed,
this
discussion
has
been
removed
from
the
11d4
discussion.

RCRA
omnibus
mandate
will
be
discussed
generically
elsewhere
in
the
preamble.

8.
Look­
Up
Table
Emission
Rate
Limits
Limits
based
on
normalized
air
concentrations
from
SCREEN3
presented
in
a
1992
guidance
document.
Section
C.
2
Less
stringent
limits
based
on
tailoring
SCREEN3
to
industrial
boiler
stack
parameters.
Limits
for
industrial
boilers
may
not
be
protective
for
HWCs
b/
c
of
stack
parameter
(
diameter,
exit
gas
velocity,
temperature)

differences.
HWC
proposal
requests
comment
on
whether
EPA
should
develop
tables
tailored
to
various
HWC
categories.

9.
Caps
on
Limits
Emission
limits
would
be
capped
at
the
Hazardous
Waste
Combustor
Interim
Standards.
Section
D
Not
relevant.
Prevents
back­
sliding.
8
10.
Stack
Test
Methods
Identifies
test
methods
that
may
be
used
for
compliance
considering
method
biases
attributable
to
feed
materials
(
e.
g.,

bromine,
sulfur)
and
alkalinity
of
particulates.
Section
F.
2
No
discussion
of
this
issue.
Hazardous
waste
feeds
and
emissions
can
contain
compounds
that
may
bias
test
method
results.

11.
Request
for
Comment
on
National
Emission
Standard
for
Cement
Kilns
Requests
comment
on
an
approach
recommended
by
CKRC
to
establish
a
national
112(
d)(
4)
emission
stnd
for
cement
kilns.
Not
relevant
12.
Time
for
Retrofits
after
Changes
Beyond
Control
of
Source
Hazardous
waste
combustor
MACT
specifies
sources
must
evaluate
every
5
years
whether
changes
beyond
the
control
of
the
source
necessitates
reducing
emission
rate
limits.
Industrial
boiler
rule
address
only
changes
over
which
source
has
control,
and
says
the
source
must
be
in
compliance
(
with
112d4
limit
or
MACT)
before
change
made.
Section
has
been
revised
to
allow
sources
up
to
3
years
after
a
change
beyond
their
control
to
make
retrofits
to
comply
with
a
more
stringent
emission
rate
limit.
3
Pope,
C.
A.
III,
D.
W.
Dockery,
J.
D.
Spangler,
and
M.
E.
Raizenne.
"
Respiratory
Health
and
PM
10
Pollution:
a
Daily
Time
Series
Analysis."
American
Review
of
Respiratory
Disease.
1991.

4
Krewski
D,
Burnett
RT,
Goldbert
MS,
Hoover
K,
Siemiatycki
J,
Jerrett
M,
Abrahamowicz
M,
White
WH.
2000.
Reanalysis
of
the
Harvard
Six
Cities
Study
and
the
American
Cancer
Society
Study
of
Particulate
Air
Pollution
and
Mortality.
Special
Report
to
the
Health
Effects
Institute,
Cambridge
MA,
July
2000.

9
G.
Valuation
of
human
health
benefits
associated
with
premature
deaths
avoided
as
a
result
of
the
particulate
matter
(
PM)
standards.

OMB
Request:
Revise
the
particulate
matter
benefits
analysis
(
methodology
and
per
case
valuation
estimates)
to
be
consistent
with
recent
OAQPS
rules.

EPA
Response:
There
are
two
primary
issues
that
relate
to
the
benefits
analysis,
risk
analysis
consistency
and
monetization
of
avoided
human
health
impact
cases.

Risk
Analysis:
There
are
two
main
differences
between
our
PM
risk
assessment
methodology
and
the
Industrial
Boiler
rule:
different
dose
response
functions,
and
exposure
assessment
methods.

Dose­
response
functions:
The
PM
benefits
presented
in
our
current
analysis
are
derived
from
the
risk
assessment
conducted
in
support
of
the
1999
action.
The
concentration­
response
functions
in
this
study
are
based
on
1995
Pope
study3.
The
PM
benefits
presented
in
the
Industrial
Boiler
uses
are
based
on
the
Krewski4
re­
analysis
of
the
1995
Pope
study.
We
did
a
comparison
of
both
studies
and
found
results
to
be
very
similar.
To
quote
from
the
Krewski
study,
"
The
Reanalysis
Team
was
able
to
reproduce
essentially
all
of
the
findings
reported
in
the
ACS
Study
using
the
same
analysis
file
as
had
been
used
by
the
Original
Investigators"
(
page
14
of
the
executive
summary).
The
relative
risk
estimated
in
the
re­
evaluation
was
1.18,
compared
to
1.17
in
the
original
Pope
study.
The
difference
was
due
to
a
slight
revision
to
the
study
cohort.
Based
on
this
finding
we
believe
that
we
are
on
safe
ground
using
the
1999
risk
assessment
based
on
the
1995
Pope
study.
We
can
add
language
saying
that
the
concentrationresponse
function
has
been
refined,
but
that
the
difference
in
results
would
be
small.
In
addition,
the
industrial
boiler
MACT
uses
a
few
different
doseresponse
functions
for
other
health
endpoints
as
well,
but
other
health
endpoints
are
a
small
portion
of
total
benefits
Exposure
Analysis:
The
Industrial
boiler
rule
used
a
national
source
receptor
matrix
while
we
used
a
facility
specific
model.
We
believe
our
10
approach
provides
greater
resolution
and
suggest
maintaining
this
approach
for
our
assessment.

Valuation:
We
applied
the
mean
mortality
valuation
(
VSL)
estimate
($
6.42
million
per
life
avoided)
developed
from
Viscusi,
adjusted
to
2002
dollars.
OMB
requests
that
OSW
use
the
valuation
figures
applied
in
the
Boiler
rule.
These
are
$
1
million,
$
10
million,
and
the
midpoint
($
5.5
million).
These
new
figures
reflect
new
information
in
the
ongoing
academic
debate
over
the
appropriate
characterization
of
the
value
of
reducing
the
risk
of
premature
mortality.
We
will
apply
these
new
figures
and
omit
the
$
6.42
million
Figure.
We
will
also
apply
revised
morbidity
valuation
estimates
that
are
consistent
with
the
Industrial
Boiler
rule.

H.
Mercury
Benefits:
Serious
developmental
abnormalities
vs.
cogitative
disabilities
caused
by
mercury
or
other
factors.

OMB
Concerns:
The
mercury
benefits
discussion
in
the
RIA
is
qualitative
only.
No
mercury
benefits
are
quantified
or
monetized.
OMB
is
concerned
that
this
qualitative
discussion
confuses
what
may
be
considered
direct
and
indirect
health
conditions
caused
by
mercury.
Furthermore,
OMB
is
concerned
that
the
discussion
appears
to
take
credit
for
reducing
some
health
conditions
that
may
be
caused
by
other
factors.

EPA
Response:
EPA
acknowledges
these
comments
and
will
modify
the
discussion.
Exhibit
6­
4
will
be
removed
from
the
benefits
chapter
and
the
text
will
be
modified
for
clarification.
Furthermore,
OSW
will
review
the
mercury
benefits
discussion
in
the
Industrial
Boiler
rule
to
ensure
general
consistency.

I.
Waste
Minimization:
Discussion
of
indirect
costs
of
waste
minimization
procedures.

OMB
Concern:
There
is
a
qualitative
waste
minimization
discussion
in
the
benefits
chapter
of
the
RIA
that
credits
the
proposed
rule
with
potentially
promoting
additional
human
health
and
ecological
benefits
as
hazardous
waste
generating
facilities
seek
to
avoid
upgrade
costs
associated
with
the
new
standards.
OMB
is
concerned
that
this
discussion
fails
to
address
associated
costs
facilities
may
experience
in
relation
to
these
waste
minimization
procedures.

EPA
Response:
A
short
discussion
of
potential
waste
minimization
cost
factors
will
be
added
to
this
section
of
the
RIA
and
the
Preamble.
11
J.
Potential
Negative
Bias
for
Method
26A
OMB
Request:
EPA
should
take
comment
on
CRWI's
concern
that
Method
26A
may
have
a
significant
negative
bias
at
low
HCl
concentrations
EPA
Response:
We
have
inserted
a
preamble
discussion
regarding
the
bias
issue
raised
by
CRWI.
This
section
explains
our
rationale
for
not
agreeing
with
CRWI's
assertion
that
Method
26A
has
a
significant
negative
bias
at
low
HCl
concentrations.
We
also
request
comment
on
the
issue.

K.
Thermal
Emission
Standards
May
Be
Below
Method
Detection
Limit
for
Some
Sources.

OMB
Request:
EPA
should
address
ACC's
concern
that
the
SVM
standard
for
liquid
fuel
boilers
may
be
below
the
detection
limit
for
some
sources.

EPA
Response:
We
have
included
a
provision
in
the
proposal
that
specifies
that
sources
are
in
compliance
if
they
sample
long
enough,
achieve
the
analytical
detection
limits
of
the
method,
and
are
not
able
to
detect
the
metal.

L.
Section
112(
d)(
3)(
A):
Data
Considered
in
Identifying
MACT
Floor
Levels
OMB
Question:
Does
the
language
of
section
112(
d)(
3)(
A)
change
EPA's
position
that
all
emissions
data
must
be
considered
in
establishing
MACT
standards?

EPA
Response:
Section
171
pertains
to
nonattainment
areas
for
a
particular
pollutant.
The
lowest
achievable
emission
rate
(
LAER)
for
a
pollutant
in
a
nonattainment
area
is
the
most
stringent
emission
limitation
which
is
contained
in
the
implementation
plan
of
any
State,
or
the
most
stringent
emission
limitation
which
is
achieved
in
practice.
Stakeholders
neither
identified
any
lowest
achievable
emission
rates
for
any
pollutants
applicable
to
nonattainment
areas
nor
identified
any
sources
that
are
subject
to
such
lowest
achievable
emission
rates.
Thus,
even
though
we
conclude
that
there
are
no
sources
to
exclude,
we
will
solicit
comment.

In
addition,
we
will
revise
the
preamble
that
discusses
the
appropriateness
of
using
emissions
data
from
sources
after
upgrading
to
comply
with
the
interim
standards
by
stating
"
we
believe"
inclusion
of
this
data
is
consistent
with
statutory
requirements
(
i.
e.,
we
will
revise
the
preamble
language
as
suggested
given
that
we
are
requesting
comment
12
on
alternative
approaches).
13
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was
marked
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43
Deletions,
41
Insertions,
1
Move.
14
3­
9F22­
04
XIII.
What
Is
the
Rationale
for
Proposing
An
Alternative
Risk­
Based
Standard
for
Total
Chlorine
in
Lieu
of
the
MACT
Standard?
Under
authority
of
CAA
Section
112(
d)(
4),
we
propose
standard
procedures
to
allow
you
to
establish
a
risk­
based
emission
limit
for
total
chlorine
in
lieu
of
compliance
with
the
section
112(
d)(
2)
MACT
emission
standard.
See
proposed
§
63.1215.
The
risk­
based
approach
would
be
applicable
to
all
hazardous
waste
combustors
except
hydrochloric
acid
production
furnaces.
Because
we
are
proposing
to
use
the
MACT
standard
for
total
chlorine
as
a
surrogate
to
control
metal
HAP
for
the
hydrogen
chloride
production
furnace
source
category,
we
cannot
allow
any
variance
from
the
standard.
For
the
other
hazardous
waste
combustor
source
categories,
we
are
proposing
the
section
112
(
d)
(
4)
standard
as
an
alternative
to
the
MACT
standard.
Sources
could
choose
which
of
these
two
standards
they
would
prefer
to
apply.
The
alternative
risk­
based
emission
limit
for
total
chlorine
would
be
based
on
national
exposure
standards
established
by
EPA
that
ensure
protection
of
public
health
with
an
ample
margin
of
safety.
The
standard
would
consist
of
a
nationally­
applicable,
uniform
algorithm
that
would
be
used
to
establish
site­
specific
emission
limitations
based
on
site­
specific
input
from
each
source
choosing
to
utilizeuse
this
approach.
Thus,
these
standards
would
provide
a
uniform
level
of
risk
reduction,
consistent
with
the
requirement
of
section
112(
d)(
4)
that
EPA
establish
"
emission
standards",
i.
e.
a
requirement
established
by
EPA
which
limits
quantity,
rate
or
concentration
of
air
emissions
(
see
CAA
section
302(
k)).
We
also
request
comment
on
an
alternative
approach
to
implement
section
112(
d)(
4)
for
cement
kilns
in
which
we
establish
a
national
risk­
based
emission
standard
for
total
chlorine
that
would
be
applicable
to
all
cement
kilns.
Under
this
approach,
EPA
would
issue
a
single
total
chlorine
emission
standard
using
an
emission
level
that
meets
our
national
exposure
standards
if
each
cement
kiln
were
to
emit
at
that
level.
We
believe
that
most
hazardous
waste
combustors
are
likely
to
consider
establishing
riskbased
standards
for
total
chlorine
because
the
MACT
standards
proposed
today
are
more
stringent,
and
in
some
cases
substantially
more
stringent,
than
currently
applicable
standards
(
e.
g.,
the
total
chlorine
standard
for
incinerators
is
currently
77
ppmv
while
we
propose
today
a
MACT
standard
of
1.4
ppmv).
We
note,
however,
that
we
request
comment
on
approaches
to
ensure
that
sources'
risk­
based
standards
for
total
chlorine
do
not
adversely
impact
acid­
sensitive
surface
waters.
If,
under
the
final
rule,
sources
that
would
adversely
impact
acid­
sensitive
surface
waters
are
ineligible
for
the
alternative
risk­
based
standards,
those
sources
would
comply
with
the
MACT
standards
for
total
chlorine.
A.
What
Is
the
Legal
Authority
to
Establish
Risk­
Based
Standards?
Under
the
authority
of
section
112(
d)(
4),
the
Administrator
may
establish
emission
standards
based
on
risk,
in
lieu
of
the
technology­
based
MACT
standards,
when
regulating
HAP
for
which
health
threshold
levels
have
been
established.
Under
section
112(
d)(
4),
Congress
gave
EPA
the
discretion
to
consider
the
health
threshold
of
any
HAP
and
to
use
that
health
threshold,
with
an
ample
margin
of
safety,
to
set
emission
standards
for
the
source
category
or
subcategory.
In
the
legislative
history
accompanying
this
provision,
the
Senate
Report
stated,
"
To
avoid
expenditures
by
regulated
entities
that
secure
no
public
health
or
environmental
benefit,
the
Administrator
is
given
discretionary
authority
to
consider
the
evidence
for
a
5
The
Agency
also
proposed
to
use
Section
112(
d)(
4)
authority
in
two
other
MACT
rulemakings­­
the
Combustion
Turbine
MACT
(
68
FR
1888,
January
14,
2003),
and
the
Chlorine
Production
MACT
(
67
FR
44671)­­
but
determined
that
MACT
standards
for
those
source
categories
are
not
warranted
and
delisted
the
source
categories
from
the
Section
112(
c)
list
of
major
sources
pursuant
to
the
authority
in
Section
112(
c)(
9).

15
health
threshold
higher
than
MACT
at
the
time
the
standard
is
under
review.
The
Administrator
is
not
required
to
take
such
factors
into
account;
that
would
jeopardize
the
standard­
setting
schedule
imposed
under
this
section
with
the
kind
of
lengthy
study
and
debate
that
has
crippled
the
current
program.
But
where
health
thresholds
are
well
established,
for
instance
in
the
case
of
ammonia,
and
the
pollutant
presents
no
risk
of
other
adverse
health
effects,
the
Administrator
may
use
the
threshold
with
an
ample
margin
of
safety
(
and
not
considering
cost)
to
set
emissions
limitations
for
sources
in
the
category
or
subcategory."
(
S.
Rep.
No.
228,
101st
Cong.
1st
Sess.
at
171
(
1989);
see
also
id.
at
175­
176
(
1989).)

EPA
has
previously
used
section
112(
d)(
4)
authority
in
the
Industrial
Boiler
and
Process
Heater
MACT
Final
Rule
signed
Feb.
26,
2004,
the
Pulp
and
Paper
MACT
Phase
II
(
66
FR
3180,
January
12,
2001)
and
the
Lime
Manufacturing
MACT
(
69
FR
394,
January
5,
2004),
and
has
proposed
to
use
it
in
a
different
manner
in
several
other
MACT
rulemakings
(
e.
g.,
the
Reciprocating
Internal
Combustion
Engine
MACT
(
67
FR
77830,
December
19,
2002).
5
The
approach
we
propose
today
is
nearly
identical
to
the
approach
EPA
recently
adopted
for
the
Industrial
Boiler
and
Process
Heater
MACT
source
category,
which
allows
a
source
to
establish
a
site­
specific
risk­
based
emission
limit
for
threshold
HAP
using
prescribed
procedures.
This
approach
differs
from
the
previous
MACT
rules
where
EPA
simply
determined,
on
a
national
basis,
what
level
of
exposure
from
each
source
in
the
category
would
be
protective
of
public
health
with
an
ample
margin
of
safety,
and
did
not
pose
significant
adverse
environmental
impacts.
This
previous
approach
resulted
in
a
determination
that
no
standard
was
necessary
because
no
source
in
the
category
could
exceed
such
a
risk­
based
standard.
Today's
proposal
varies
in
that
the
level
of
protection
afforded
by
the
standard
is
uniform,
but
the
limits
for
individual
sources
differ
due
to
site­
specific
factors.
As
explained
later
in
this
section
of
the
preamble,
EPA
is,
however,
also
considering
for
cement
kilns
applying
the
single
national
standard
approach
adopted
in
earlier
rules.
B.
What
Is
the
Rationale
for
the
National
Exposure
Standards?
We
identify
as
national
exposure
standards
threshold
levels
that
are
protective
of
human
health
from
both
chronic
and
acute
exposure.
In
addition,
because
EPA
has
discretion
whether
or
not
to
promulgate
risk­
based
standards
pursuant
to
section
112(
d)(
4),
we
would
not
allow
an
alternative
standard
where
emission
levels
may
result
in
adverse
environmental
effects
that
would
otherwise
be
reduced
or
eliminated.
We
would
not
issue
the
alternative
standard
even
though
it
may
be
shown
that
emissions
do
not
approach
or
exceed
levels
requisite
to
protect
public
health
with
an
ample
margin
of
safety
because
we
believe
the
statute
requires
that
we
consider
effects
on
terrestrial
animals,
plants,
and
aquatic
ecosystems
in
addition
to
public
health
in
establishing
a
standard
pursuant
to
section
112(
d)(
4).
See
S.
Rep.
228
at
176:
"
Employing
a
health
threshold
or
6
EPA
conducted
an
assessment
of
the
carcinogenicity
of
chlorine
gas
and
concluded
that
it
is
not
likely
to
be
a
human
carcinogen
(
see
EPA's
June
22,
1999
Risk
Assessment
Issue
Paper
for
Derivation
of
a
Provisional
Chronic
Inhalation
RfC
for
Chlorine,
p.
12).
The
International
Agency
for
Research
on
Cancer
(
IARC)
concluded
that
hydrochloric
acid
is
not
classifiable
as
to
its
carcinogenicity
to
humans
(
see
IARC
Monographs,
Vol.
54:
Occupational
Exposures
to
Mists
and
Vapours
from
Strong
Inorganic
Acids;
and
Other
Industrial
Chemicals
(
1992)
p.
189).

7
See
EPA's
externally
peer­
reviewed
"
Risk
Assessment
Issue
Paper
for
Derivation
of
a
Provisional
Chronic
Inhalation
RfC
for
Chlorine"
(
June
22,
1999)
that
can
be
found
in
the
docket
for
today's
proposal.

8
As
determined
by
a
modeling
analysis
done
by
the
Air
Pollution
Research
Center
at
the
University
of
California
at
Riverside,
as
reported
in
a
California
Air
Resources
Board
fact
sheet,
"
Toxic
Air
Contaminant
Identification
List
Summaries
­
ARB/
SSD/
SES,"
p.
231,
September
1997.
See
also
http://
www.
arb.
ca.
gov/
toxics/
tac/
factshts/
chlorine.
pdf.

16
safety
level
rather
than
the
MACT
criteria
to
set
standards
shall
not
result
in
adverse
environmental
effects
which
would
otherwise
be
reduced
or
eliminated."
1.
What
Are
the
Human
Health
Threshold
Levels?
a.
Chronic
Exposure.
Hydrogen
chloride
is
corrosive
to
the
eyes,
skin,
and
mucous
membranes.
Chronic
exposure
may
cause
gastritis,
bronchitis,
dermatitis,
and
dental
discoloration
and
erosion.
Chronic
exposure
to
chlorine
gas
can
cause
respiratory
effects
including
eye
and
throat
irritation
and
airflow
obstruction.
See
discussion
in
Part
One,
Section
I.
E
of
this
preamble.
Given
that
neither
hydrogen
chloride
nor
chlorine
gas
is
known
to
produce
a
carcinogenic
response6,
we
use
reference
air
concentrations
(
RfC)
to
assess
the
likelihood
of
non­
cancer
health
effects
in
humans.
The
RfC
is
an
estimate
of
a
continuous
inhalation
exposure
to
the
human
population,
including
sensitive
subgroups,
that
is
likely
to
be
without
an
appreciable
risk
of
deleterious
effects
over
a
lifetime.
We
use
an
RfC
for
hydrogen
chloride
of
20
ug/
m3,
as
presented
in
EPA's
Integrated
Risk
Information
System
(
IRIS).
We
propose
to
use
an
RfC
for
chlorine
gas
of
0.2
ug/
m3
based
on
a
provisional
assessment
prepared
by
EPA
on
inhalation
hazards
from
chlorine.
7
This
is
the
same
as
the
value
for
chlorine
used
by
the
State
of
California's
Office
of
Environmental
Health
Hazard
Assessment,
which
they
refer
to
as
a
chronic
"
Reference
Exposure
Level"
(
REL).
3
Because
RfCs
can
change
over
time
based
on
new
information,
the
rule
would
require
you
to
use
the
current
RfC
value
found
at
http://
epa.
gov/
ttn/
atw/
toxsource/
sumnmary.
html.
We
considered
how
to
account
for
the
fact
that
chlorine
gas
photolyzes
in
the
atmosphere
in
bright
sunlight
to
chlorine
ions
and
then
quickly
reacts
with
hydrogen
or
methane
to
form
hydrogen
chloride.
The
half­
life
of
chlorine
due
to
photolysis
in
bright
sunlight
is
estimated
to
be
10
minutes.
8
Nonetheless,
this
is
generally
sufficient
time
for
the
plume
to
reach
nearby
groundlevel
receptors
without
significant
transformation.
In
addition,
such
transformation
is
possible
only
a
portion
of
the
time.
Photolysis
does
not
occur
at
night
and
is
reduced
on
overcast
or
cloudy
days.
Generally
speaking,
the
rate
of
photolysis
depends
on
the
particular
wavelength
and
9
The
full
definitions
of
the
AEGL
values
are
more
nuanced.
AEGL
1:
The
airborne
concentration
of
a
substance
above
which
it
is
predicted
that
the
general
population,
including
susceptible
individuals,
could
experience
notable
discomfort,
irritation,
or
certain
asymptomatic
nonsensory
effects.
However,
the
effects
are
not
disabling
and
are
transient
and
reversible
upon
cessation
of
exposure.
AEGL
2:
The
airborne
concentration
of
a
substance
above
which
it
is
predicted
that
the
general
population,
including
susceptible
individuals,
could
experience
irreversible
or
other
serious,
long­
lasting
adverse
health
effects
or
an
impaired
ability
to
escape.
AEGL
3:
The
airborne
concentration
of
a
substance
above
which
it
is
predicted
that
the
general
population,
including
susceptible
individuals,
could
experience
life­
threatening
health
effects
or
death.

10
For
hydrogen
chloride
and
chlorine
gas
(
individually),
the
AEGL­
1
values
for
10­
minute,
30­
minute,
1­
hour,
and
8­
hour
exposures
are
the
same.
Therefore,
when
comparing
17
intensity
of
solar
radiation
reaching
the
earth's
surface
which
varies
greatly
depending
on
the
solar
angle
which
changes
with
the
time
of
day,
the
season
of
the
year,
and
the
latitude
at
a
given
location.
While
the
ideal
approach
would
be
explicit
modeling
of
photolysis
rates
as
a
function
of
solar
insolation,
sky
conditions,
absorption
cross­
section,
quantum
yield,
and
subsequent
transformation
to
hydrogen
chloride,
to
our
knowledge
no
such
regulatory
air
dispersion
model
currently
exists.
Because
it
is
reasonable
to
believe
that
receptors
will
be
exposed
to
chlorine
gas
before
appreciable
transformation
occurs
due
to
the
variability
and
complexity
of
the
transformation
and
the
fact
that
chlorine
gas
is
considerably
more
toxic
than
hydrogen
chloride,
we
conclude
that,
for
the
purpose
of
protection
of
public
health,
it
is
prudent
to
assume
that
chlorine
gas
is
not
transformed
to
hydrogen
chloride.
b.
Acute
Threshold
Levels.
Short­
term
exposure
to
hydrogen
chloride
may
cause
eye,
nose,
and
respiratory
tract
irritation
and
inflamation
and
pulmonary
edema.
Short­
term
exposure
to
high
levels
of
chlorine
gas
can
result
in
chest
pain,
vomiting,
toxic
pneumonitis,
and
pulmonary
edema.
At
lower
levels,
chlorine
gas
is
a
potent
irritant
to
the
eyes,
the
upper
respiratory
tract,
and
lungs.
See
Part
One,
Section
I.
E.
To
assess
effects
from
acute
exposure,
we
propose
to
use
the
acute
exposure
guideline
level
(
AEGL).
AEGL
toxicity
values
are
estimates
of
adverse
health
effects
due
to
a
single
exposure
lasting
8
hours
or
less.
Consensus
toxicity
values
for
effects
of
acute
exposures
have
been
developed
by
several
different
organizations.
EPA,
in
conjunction
with
the
National
Research
Council
and
National
Academy
of
Sciences,
is
in
the
process
of
setting
acute
exposure
guideline
levels.
A
national
advisory
committee
organized
by
EPA
has
developed
AEGLs
for
priority
chemicals
for
10­
minute,
30­
minute,
1­
hour,
4­
hour,
and
8­
hour
airborne
exposures.
They
have
also
determined
for
each
exposure
duration
the
levels
of
these
chemicals
that
will
protect
against
notable
discomfort
(
AEGL­
1),
serious
effects
(
AEGL­
2),
and
life­
threatening
effects
or
death
(
AEGL­
3).
9
To
be
protective
of
public
health,
we
propose
to
use
the
AEGL­
1
values
to
assess
acute
exposure:
2.7
mg/
m3
(
1.8
ppm)
for
hydrogen
chloride,
and
1.4
mg/
m3
(
0.5
ppm)
for
chlorine
gas.
10
Airborne
concentrations
of
a
substance
above
the
AEGL­
1
could
cause
predicted
ambient
levels
of
exposure
to
the
AEGL­
1
value,
we
believe
it
is
reasonable
to
evaluate
maximum
1­
hour
ground
level
concentrations.

11
See
US
EPA
Glossary
of
Key
Terms
for
National
Air
Toxics
Assessment,
at
http://
www.
epa.
gov/
ttn/
atw/
nata/
gloss1.
html.

18
notable
discomfort,
irritation,
or
certain
asymptomatic
nonsensory
effects
in
the
general
population,
including
susceptible
individuals.
Please
note,
however,
that
airborne
concentrations
below
the
AEGL­
1
could
produce
mild
odor,
taste,
or
other
sensory
irritations.
Effects
above
the
AEGL­
1
(
but
below
the
AEGL­
2)
are
not
disabling
and
are
transient
and
reversible
upon
cessation
of
exposure.
2.
What
Exposures
Would
You
Be
Required
to
Assess?
We
discuss
below
the
following
issues:
(
1)
use
of
the
Hazard
Index
to
assess
exposure
to
both
hydrogen
chloride
and
chlorine
gas;
(
2)
exposure
to
emissions
of
respiratory
irritant
HAP
other
than
hydrogen
chloride
and
chlorine
gas;
(
3)
exposure
to
emissions
of
respiratory
irritant
HAP
from
collocated
sources;
(
4)
exposure
to
ambient
background
levels
of
respiratory
irritant
HAP;
and
(
5)
whether
acute
exposure
needs
to
be
assessed
if
the
Hazard
Index
for
chronic
exposure
is
expected
to
be
higher
in
all
situations.
a.
Hazard
Index.
Noncancer
risk
assessments
typically
use
a
metric
called
the
Hazard
Quotient
(
HQ)
to
assess
risks
of
exposures
to
noncarcinogens.
The
HQ
is
the
ratio
of
a
receptor's
potential
exposure
(
or
modeled
concentration)
to
the
health
reference
value
or
threshold
level
(
e.
g.,
RfC
or
AEGL)
for
an
individual
pollutant.
HQ
values
less
than
1.0
indicate
that
exposures
are
below
the
health
reference
value
or
threshold
level
and,
therefore,
that
such
exposures
are
without
appreciable
risk
of
adverse
effects
in
the
exposed
population.
HQ
values
above
1
do
not
necessarily
imply
that
adverse
effects
will
occur,
but
that
the
likelihood
of
such
effects
in
a
given
population
increases
as
HQ
values
exceed
1.0.11
When
the
risk
of
noncancer
effects
from
exposure
to
more
than
one
pollutant
to
the
same
target
organ
must
be
assessed,
the
effects
are
generally
considered
to
be
additive
and
the
HQ
values
for
each
pollutant
are
summed
to
form
an
analogous
metric
called
the
Hazard
Index
(
HI).
Assuming
additivity,
HI
values
less
than
1.0
indicate
that
exposures
to
the
mixtures
are
likely
to
be
without
appreciable
risk
of
adverse
effects
in
the
exposed
population.
HI
values
above
1.0
do
not
necessarily
imply
that
adverse
effects
from
exposure
to
the
mixture
will
occur,
but
that
the
likelihood
of
such
effects
in
a
given
population
increases
as
HI
values
exceed
1.0.
For
purposes
of
establishing
risk­
based
emission
limits
for
total
chlorine,
we
propose
to
allow
a
maximum
HI
value
of
not
greater
than
1.0.
b.
Exposure
to
Emissions
of
Respiratory
Irritant
HAP
other
than
Hydrogen
Chloride
and
Chlorine
Gas
that
Have
a
Common
Mechanism
of
Action.
We
have
identified
in
the
table
below
40
HAP
that
are
respiratory
irritants,
including
hydrogen
chloride
and
chlorine
gas.
See
Table
XX.
Because
these
HAP
affect
the
same
target
organ,
have
a
common
mechanism
of
action,
we
must
determine
whether
exposure
to
these
HAP
must
be
considered
when
determining
that
the
HI
is
less
than
or
equal
to
1.0.
19
Text
Moved
Here:
1
Respiratory
Irritant
HAP
1,2­
Epoxybutane
Hexachlorocyclopentadiene
1,3­
dichloropropene
Hexamethylene
1,6­
diisocyanate
2,4­
Toluene
diisocyanate
Hydrochloric
acid
2­
Chloroacetophenone
Maleic
anhydride
Acetaldehyde
Methyl
bromide
Acrolein
Methyl
isocyanate
Acrylic
acid
Methyl
methacrylate
Acrylonitrile
Methylene
diphenyl
diisocyanate
N­
hexane
Antimony
Naphthalene
Beryllium
Nickel
Bis(
2­
ethylhexyl)
phthalate
Nitrobenzene
Chlorine
Phosgene
Chloroprene
Phthalic
anhydride
Chromium
Propylene
dichloride
Cobalt
Propylene
oxide
Diethanolamine
Styrene
oxide
Epichlorohydrin
Titanium
tetrachloride
Ethylene
glycol
Toluene
Formaldehyde
Triethylamine
Vinyl
acetate
End
Of
Moved
Text
WIn
making
this
determination,
we
would
consider
only
those
respiratory
irritants
that
are
HAP
(
as
opposed
to
also
considering
respiratory
irritants
that
are
criteria
pollutants)
not
only
because
Ssection
112
deals
with
control
of
emissions
of
HAP,
but
also
because
ambient
levels
of
criteria
pollutants
that
target
the
respiratory
systemhave
a
common
mechanism
of
action
with
12
Betty
Willis,
et
al,
Agency
for
Toxic
Substances
and
Disease
Registry,
US
Department
of
Health
and
Human
Services,
"
Public
Health
Reviews
of
Hazardous
Waste
Thermal
Treatment
Technologies:
A
Guidance
Manual
for
Public
Health
Assessors,"
March
2002,
Table
4.

20
hydrogen
chloride
and
chlorine
gas
(
e.
g.,
SO
x,
NO
x,,
PM,
ozone)
are
controlled
through
the
applicable
State
Implementation
Plans
demonstrating
compliance
with
the
National
Ambient
Air
Quality
Standards
for
these
pollutants.
c.
Exposure
to
Emissions
of
Respiratory
Irritant
HAP
from
Collocated
Sources.
You
would
be
required
to
account
for
exposure
to
emissions
of
respiratory
irritant
HAP
from
all
onsite
hazardous
waste
combustors
subject
to
Subpart
EEE,
Part
63.
EPA
will
address
exposure
to
emissions
of
respiratory
irritant
HAP
from
other
sources
that
may
be
collocated
with
a
hazardous
waste
combustor­­
for
example,
process
vents
and
fossil
fuel
boilers­­
under
the
residual
risk
requirements
of
section
112(
f)
for
both
hazardous
waste
combustors
and
(
potentially)
other
MACT
source
categories.
See
A
Legislative
History
of
the
Clean
Air
Act
Amendments
of
1990
(
Senate
Print
103­
38,
103d
Cong.
1st
sess.)
vol.
1
at
868­
69
(
floor
statement
of
Sen.
Durenberger
(
Senate
floor
manager
for
section
112)
during
debate
on
the
Conference
Report,
indicating
that
EPA
is
obligated
to
consider
"
combined
risks
of
all
sources
that
are
collocated
with
such
sources
within
the
same
major
source"
but
going
on
to
state
that
the
determination
of
ample
margin
of
safety
from
emissions
from
all
collocated
sources
need
not
occur
at
the
same
time,
but
rather
can
be
spread
out
over
the
course
of
the
residual
risk
determination
process
for
all
major
sources.
In
addition
to
hydrogen
chloride
and
chlorine
gas,
several
of
the
respiratory
irritant
HAP
listed
in
Tthe
table
XXabove
may
be
emitted
by
hazardous
waste
combustors,
including
the
metals
antimony
trioxide,
beryllium,
chromium
(
VI),
cobalt,
and
nickel,
and
the
organic
compounds
Bis(
2­
ethylhexyl)
phthalate,
formaldehyde,
napthalene,
and
toluene.
12
We
do
not
believe,
however,
that
these
respiratory
irritant
HAP
would
be
emitted
by
hazardous
waste
combustors
at
levels
that
would
result
in
significant
Hazard
Quotient
values.
Beryllium
and
chromium
would
be
controlled
by
emission
standards
for
low
volatile
metals
and
the
remaining
metal
HAP
would
be
controlled
by
a
particulate
matter
standard.
Emissions
of
the
respiratory
irritant
organic
HAP
would
be
controlled
to
trace
levels
by
the
MACT
standards
for
carbon
monoxide
or
hydrocarbons
and
destruction
and
removal
efficiency
(
DRE).
Accordingly,
we
propose
to
require
you
to
quantify
and
assess
emissions
from
the
hazardous
waste
combustor
of
hydrogen
chloride
and
chlorine
gas
only;
you
would
not
be
required
to
account
for
these
other
respiratory
irritant
HAP
because
they
would
not
contribute
substantially
to
the
Hazard
Index.

Table
XX
c.
Exposure
to
Emissions
of
Text
Was
Moved
From
Here:
1
Respiratory
Irritant
HAP
from
Collocated
Sources.
You
would
be
required
to
account
for
exposure
to
emissions
of
hydrogen
chloride
and
chlorine
gas
from
all
on­
site
hazardous
waste
combustors
subject
to
Subpart
EEE,
Part
63.
EPA
will
address
exposure
to
emissions
of
respiratory
irritant
HAP
from
other
sources
that
may
be
collocated
with
a
hazardous
waste
combustor­­
for
example,
process
vents
and
fossil
fuel
boilers­­
under
the
residual
risk
13
See
Trinity
Consultants,
"
Analysis
of
HCl/|
Cl2
Emissions
from
Cement
Kilns
for
112(
d)(
4)
Consideration
in
the
HWC
MACT
Replacement
Standards,"
September
17,
2003.

14
See
USEPA,
"
Human
Health
and
Ecological
Risk
Assessment
Support
to
the
Development
of
Technical
Standards
for
Emissions
from
Combustion
Units
Burning
Hazardous
Wastes:
Background
Document,"
July
1999.

21
requirements
of
section
112(
f)
for
both
hazardous
waste
combustors
and
(
potentially)
other
MACT
source
categories.
See
A
Legislative
History
of
the
Clean
Air
Act
Amendments
of
1990
(
Senate
Print
103­
38,
103d
Cong.
1st
sess.)
vol.
1
at
868­
69
(
floor
statement
of
Sen.
Durenberger
(
Senate
floor
manager
for
section
112)
during
debate
on
the
Conference
Report,
indicating
that
EPA
is
obligated
to
consider
"
combined
risks
of
all
sources
that
are
collocated
with
such
sources
within
the
same
major
source"
but
going
on
to
state
that
the
determination
of
ample
margin
of
safety
from
emissions
from
all
collocated
sources
need
not
occur
at
the
same
time,
but
rather
can
be
spread
out
over
the
course
of
the
residual
risk
determination
process
for
all
major
sources.
d.
Exposure
to
Ambient
Background
Levels
of
Respiratory
Irritant
HAP.
Background
levels
of
respiratory
irritant
HAP
attributable
to
emissions
from
off­
site
sources
would
not
be
considered
when
establishing
risk­
based
limits
for
total
chlorine
under
section
112(
d)(
4).
Rather,
these
background
levels
will
be
addressed
(
as
may
be
necessary)
through
other
CAA
programs
such
as
the
urban
air
toxics
program.
e.
Acute
Exposure
Need
Not
Be
Assessed.
We
have
determined
that
you
need
not
assess
acute
exposure
to
establish
an
emission
limit
for
total
chlorine.
You
would
not
be
required
to
model
maximum
1­
hour
average
off­
site
ground
level
concentrations
to
calculate
a
Hazard
Index
(
HI)
based
on
acute
exposure
for
purposes
of
establishing
an
emission
limit
for
total
chlorine.
We
conclude
that
the
chronic
exposure
Hazard
Index
(
HI)
for
the
hazardous
waste
combustor(
s)
would
always
exceed
the
acute
exposure
HI.
Thus,
the
emission
limit
for
total
chlorine
based
on
chronic
exposure
would
always
be
more
stringent
thatn
the
limit
based
on
acute
exposure.
As
an
example,
the
Cement
Kiln
Recycling
Coalition
evaluated
both
chronic
and
acute
exposure
to
hydrogen
chloride
and
chlorine
gas
for
the
14
cement
facilities
that
burn
hazardous
waste.
13
In
all
cases,
the
chronic
HI
exceeded
the
acute
HI.
In
addition,
we
determined
that
the
Hazard
Quotient
(
HQ)
for
chronic
exposure
was
always
higher
than
the
HQ
for
acute
exposure
for
the
HAP
we
evaluated
in
the
risk
assessment
we
used
to
support
the
1999
Final
MACT
Rule
for
hazardous
waste
combustors.
14
Not
requiring
an
acute
exposure
analysis
reduces
the
burden
on
both
the
regulated
community
and
regulatory
officials
to
develop
and
review
an
analysis
that
would
be
superseded
by
the
chronic
exposure
analysis
when
establishing
an
emission
limit
for
total
chlorine.
Please
note
that
this
discussion
relates
to
evaluating
acute
exposure
in
establishing
an
emission
limit
for
total
chlorine.
Although
we
conclude
that
the
chronic
exposure
Hazard
Index
would
always
be
higher
than
the
acute
exposure
Hazard
Index,
and
thus
would
be
the
basis
for
the
total
chlorine
emission
rate
limit,
this
relates
to
acute
versus
chronic
exposure
to
a
constant,
maximum
average
(
e.
g.,
a
maximum
annual
average)
emission
rate
of
total
chlorine
from
a
hazardous
waste
combustor.
Acute
exposure
must
be
considered,
however,
when
establishing
operating
requirements
(
e.
g.,
feedrate
limit
for
total
chlorine
and
chloride)
to
ensure
that
short­
15
Indeed,
using
the
classic
two­
step
approach
to
"
ample
margin
of
safety"
could
result
in
the
same
standards
we
are
proposing
as
MACT
for
HCl
and
Cl
2
for
all
of
the
affected
source
categories
(
if
one
assumes
that
all
of
the
standards
would
be
below
protective
risk­
based
levels
for
all
sources),
since
we
believe
that
the
proposed
technology­
based
standards
would
be
justifiable
based
on
considerations
of
technical
feasibility
and
cost,
and
so
would
provide
a
reasonable
margin
of
safety
beyond
the
risk­
based
level
considered
protective.

22
term
emissions
do
not
result
in
an
acute
exposure
Hazard
Index
of
1.0
or
greater
even
though
long­
term
(
e.
g.,
annual
average)
emissions
do
not
exceed
the
limit.
See
discussion
in
Section
FG.
1
below.
3.
Does
the
Proposed
Approach
Ensure
an
Ample
Margin
of
Safety?
Section
112(
d)(
4)
allows
EPA
to
develop
risk­
based
standards
for
HAP
"
for
which
a
health
threshold
has
been
established",
and
the
resulting
standard
is
to
provide
an
"
ample
margin
of
safety."
The
"
ample
margin
of
safety"
standard,
at
least
as
applied
to
nonthreshold
pollutants,
typically
connotes
a
two­
step
process
(
based
on
the
standard
first
announced
in
the
so­
called
Vinyl
Chloride
decision
(
NRDC
v.
EPA,
824
F.
2d
at
1146
(
D.
C.
Cir.
1987)),
whereby
EPA
"
first
[
determines]
...
a
`
safe'
or
`
acceptable'
level
of
risk
considering
only
health
factors,
followed
by
a
second
step
to
set
a
standard
that
provides
an
`
ample
margin
of
safety',
in
which
costs,
feasibility,
and
other
relevant
factors
in
addition
to
health
may
be
considered."
54
FR
at
38045.
It
is
not
clear
that
Congress
intended
this
analysis
to
apply
to
Section
112(
d)(
4)
standards,
since
the
principal
legislative
history
to
the
provision
indicates
that
costs
are
not
to
be
considered
in
setting
standards
under
Section
112(
d)(
4)
(
S.
Rep.
228
at
173),
whereas
cost
normally
is
a
relevant
consideration
in
the
second
part
of
the
ample
margin
of
safety
process,
as
described
above.
Further,
if
issues
of
feasibility,
cost,
and
other
non­
health
factors
are
to
be
taken
into
account
in
establishing
Section
112(
d)(
4)
standards,
it
would
be
exceedingly
difficult,
if
not
practically
impossible,
to
do
so
on
a
site­
specific
basis,
undermining
the
approach
we
are
proposing
here.
Nor
is
it
clear
that
the
two­
step
approach
is
necessarily
warranted
when
considering
threshold
pollutants,
since
there
is
greater
certainty
regarding
levels
at
which
adverse
health
effects
occur.
See
Vinyl
Chloride,
824
F.
2d
at
1165
n.
11.15
We
specifically
request
comment
on
how
to
ensure
that
the
emission
limits
calculated
using
the
health
threshold
values
(
e.
g.,
RfCs
and
AEGL­
1
values),
and
after
considering
collocated
sources
of
emissions
of
respiratory
irritant
HAP,
achieve
an
ample
margin
of
safety.
4.
Use
of
RCRA
Omnibus
Authority
to
Address
Exposures
Not
Accounted
for
Immediately
under
Section
112(
d)(
4)
As
set
out
above,
EPA
will
address
exposure
to
emissions
of
respiratory
irritant
HAP
from
other
collocated
sources
(
e.
g.,
process
vents,
fossil
fuel
boilers)
under
the
section
112
MACT
program
during
the
residual
risk
analysis
under
section
112(
f).
This
analysis
would
occur
within
eight
years
after
promulgation
of
a
MACT
standard.
We
also
explained
that
EPA
will
address
exposure
to
background
levels
of
respiratory
irritants
attributable
to
off­
site
sources
under
other
CAA
programs.
EPA
is
required
under
the
RCRA
omnibus
permit
authority,
however,
to
ensure
that
RCRA
permits
are
protective
of
human
health
and
the
environment.
See
RCRA
section
3005(
c)(
3)
and
40
CFR
270.32(
b)(
2).
Accordingly,
EPA
would
use
that
RCRA
authority
to
16
EPA
published
the
final
rule
at
69
FR
394,
January
5,
2004.

23
ensure
that
risk­
based
emission
limits
established
under
section
112(
d)(
4)
are
protective
of
human
health
and
the
environment
considering
all
relevant
exposures
to
respiratory
irritants.
For
example,
this
determination
could
be
made
for
existing
sources
with
RCRA
permits
when
you
request
to
have
the
emission
limits
that
have
been
superseded
by
the
MACT
emission
standards
removed
from
your
RCRA
permit
(
i.
e.,
when
you
submit
the
Notification
of
Compliance
under
§
§
63.1207(
j))
and
63.1210(
b).
For
new
RCRA
sources,
this
determination
could
be
made
before
the
RCRA
permit
is
issued.
54.
How
Are
Effects
on
Terrestrial
Animals
Addressed?
We
believe
the
RfC
values
for
hydrogen
chloride
and
chlorine
gas
should
be
generally
protective
for
chronic
effects
in
most,
if
not
all,
fauna.
We
note
that
the
RfC
values
are
based
on
animal
studies.
Although
the
AEGL­
1
values
for
acute
exposure
are
based
on
human
data,
we
nonetheless
expect
that
they
too
would
be
generally
protective
of
most
fauna,
absent
information
to
the
contrary.
65.
How
Are
Effects
on
Plants
Addressed?
EPA
has
not
established
ecotoxicity
values
that
are
protective
of
vegetation.
Nonetheless,
for
the
reasons
discussed
below
we
do
not
believe
that
ambient
concentrations
of
hydrogen
chloride
and
chlorine
gas
that
meet
the
human
health
threshold
values
discussed
above
will
pose
adverse
effects
on
plants.
As
discussed
in
the
preamble
to
the
Lime
Manufacturing
NESHAP
proposed
rule
(
67
FR
78056)
16,
chronic
exposure
to
about
600
µ
g/
m3
can
be
expected
to
result
in
discernible
effects,
depending
on
the
plant
species.
Effects
of
acute,
20­
minute
exposures
of
6,500
to
27,000
g/
m3
include
leaf
injury
and
decrease
in
chlorophyll
levels
in
various
species.
The
hydrogen
chloride
RfC
of
20
µ
g/
m3
is
well
below
the
600
µ
g/
m3
effect
level,
and
the
AEGL­
1
value
for
hydrogen
chloride
of
2,700
µ
g/
m3
is
far
below
the
6500
µ
g/
m3
acute
effect
level.
Therefore,
no
adverse
exposure
effects
are
anticipated.
We
specifically
request
additional
information
on
ecotoxicity
for
both
acute
and
chronic
exposure
of
vegetation
to
hydrogen
chloride
and
chlorine
gas.
7.
Should
Surface
Water
Acidification
Effects
Be
Addressed?
We
are
concerned
about
the
potential
for
elevated
wet
and
dry
deposition
of
hydrogen
chloride
and,
particularly,
its
effects
on
acid­
sensitive
surface
waters.
13
Because
use
of
section
112(
d)(
4)
is
discretionary,
and
the
potential
for
adverse
environmental
effects
is
a
relevant
factor
to
consider
in
exercising
that
discretion,
we
request
comment
on
whether
and
how
we
should
address
acidification
of
acid­
sensitive
surface
waters.
Although
limited
ecotoxicological
studies
of
hydrogen
chloride
suggest
that
the
RfC
for
chronic
human
health
effects
is
protective
of
direct
toxic
effects
on
plants
and
animals,
indirect
effects
on
both
aquatic
and
terrestrial
ecosytems
could
be
significant
due
to
the
long­
term
effects
of
acidification.
In
particular,
ambient
air
concentrations
of
hydrogen
chloride
at
the
level
of
the
RfC
could
result
in
wet
(
e.
g.,
rain
and
snow
fall)
and
dry
deposition
of
hydrogen
ions
that
in
some
places
would
exceed
by
many­
fold
the
background
deposition
of
hydrogen
ions
associated
with
ambient
levels
of
sulfates
and
nitrates,
which
are
the
primary
cause
of
acid
deposition
(
i.
e.,
commonly
called
acid
rain).
Therefore,
adverse
environmental
effects
from
hydrogen
chloride
24
emissions
could
occur
in
acid­
sensitive
environments
at
levels
below
those
of
concern
to
human
health,
and
these
effects
would
not
be
addressed
by
EPA's
acid
rain
program.
The
case
is
less
clear
for
chlorine
gas
due
to
the
highly
variable
and
competing
rates
of
transformation
to
hydrogen
chloride,
as
discussed
above.
Because
the
typical
delay
in
transformation
to
hydrogen
chloride
should
provide
sufficient
time
for
dilution
to
occur,
deposition
of
hydrogen
chloride
from
chlorine
emissions
is
not
likely
to
be
significant.
Therefore,
you
might
account
for
hydrogen
chloride
emissions
only
(
i.
e.,
not
chlorine
gas
as
well)
when
determining
the
impact
of
the
combustor's
emissions
on
acid­
sensitive
surface
waters.
To
identify
acid­
sensitive
surface
waters,
we
could
use
the
metric
of
acid
neutralization
capacity.
Whether
surface
waters
can
resist
acidification
depends
on
the
ability
of
the
water
and
watershed
soil
to
neutralize
the
acid
deposition
it
receives.
The
best
measure
of
this
ability
is
acid
neutralizing
capacity
(
ANC),
determined
by
the
amount
of
dissolved
compounds
that
will
counteract
acidity.
ANC
depends
largely
on
the
surrounding
watershed's
physical
characteristics
such
as
geology,
soils
and
size.
Surface
water
with
an
ANC
of
200
micro
equivalents
per
liter
(
eq/
L)
is
normal;
ANC
less
than
50
micro
equivalents
per
liter
is
considered
highly
sensitive
to
acidification.
Some
surface
waters
in
Florida,
the
Northeast,
the
Mid­
Atlantic,
Upper
Midwest
and
parts
of
the
West
are
extremely
sensitive
to
acidification
(
with
surface
water
ANC
of
less
than
zero).
To
ensure
that
hydrogen
chloride
emissions
do
not
result
in
adverse
environmental
effects
which
would
otherwise
be
reduced
or
eliminated,
we
could
restrict
eligibility
for
the
alternative
risk­
based
standards
for
sources
located
within
20
kilometers
of
surface
waters
with
an
ANC
of
50
micro
equivalents
per
liter
or
less.
EPA
has
information
on
the
ANC
level
of
many
surface
waters.
See
http://
www.
epa.
gov/
airmarkets/
cmap/
mapgallery/
mg_
acidic_
waters.
html.
Although
the
map
provided
at
this
web
site
identifies
regions
of
the
US
that
have
surface
waters
with
an
ANC
of
zero
or
less,
we
infer
from
this
information
that
surface
waters
in
the
vicinity
of
most
hazardous
waste
combustors
are
not
likely
to
have
an
ANC
of
50
micro
equivalents
per
liter
or
less.
This
includes
areas
such
as
Texas,
Louisiana,
and
the
midwest.
Thus,
this
criterion
should
not
preclude
eligibility
for
the
risk­
based
limits
for
most
hazardous
waste
combustors.
14
We
acknowledge,
however,
that
data
are
not
likely
to
be
available
for
many
specific
surface
waters
in
the
vicinity
of
hazardous
waste
combustors.
We
request
comment
on
how
to
address
this
issue.
For
example,
you
could
assume
that
the
ANC
of
your
surface
waters
are
the
same
as
those
of
the
nearest
appropriate
surface
waters
for
which
there
are
ANC
data,
or
you
could
potentially
sample
and
analyze
representative
types
of
surface
waters
within
50
kilometers
of
the
stack
and
assume
other
surface
waters
have
the
same
ANC
as
those
you
test.
15
We
also
request
comment
on
an
approach
to
gauge
whether
emissions
of
hydrogen
chloride
from
the
hazardous
waste
combustor
would
be
likely
to
pose
a
substantial
incremental
impact
on
acid­
sensitive
surface
waters
given
background
impacts.
Even
if
the
facility
is
located
proximate
to
acid­
sensitive
surface
waters,
it
may
be
appropriate
to
establish
risk­
based
emission
limits
for
total
chlorine
for
the
combustor
if
the
incremental
contribution
to
acidification
from
the
facility
is
not
substantial
when
considering
background
sources
of
acidification.
Under
this
approach,
you
would
model
wet
and
dry
deposition
of
hydrogen
chloride
emissions
from
the
combustor
and
determine
whether
the
deposition
of
hydrogen
ion
equivalents
attributable
to
your
emissions
contribute
significantly
to
the
background
deposition
of
hydrogen
ion
equivalents
17
Rather
than
establishing
emission
rate
limits
for
hydrogen
chloride
and
chlorine
gas,
or
for
total
chlorine,
for
each
combustor,
you
would
actually
establish
an
HCl­
equivalent
emission
rate
limit
for
each
combustor,
as
discussed
below
in
the
text.

25
attributable
to
sulfate
(
SO
4
­
2),
nitrate
(
NO
3
­),
and
chloride
(
Cl­).
We
could
conclude
that
surface
waters
with
an
ANC
of
zero
micro
equivalents
per
liter
or
less
would
be
significantly
impacted
if
emissions
of
hydrogen
chloride
from
your
source
result
in
deposition
of
hydrogen
ion
equivalents
to
surface
water
exceeding
ten
percent
of
the
background
hydrogen
ion
equivalents
from
deposition
of
sulfate
(
SO
4
­
2),
nitrate
(
NO
3
­),
and
chloride
(
Cl­).
Although
such
surface
waters
are
critically
acid­
sensitive,
if
the
hazardous
waste
combustor
is
projected
to
increase
background
levels
by
only
10
percent,
the
effect
may
not
be
significant
given
the
uncertainties
in
the
analysis.
For
less
sensitive
surface
waters
with
an
ANC
greater
than
zero
but
less
than
50
micro
equivalents
per
liter,
we
could
conclude
that
these
waters
would
be
significantly
impacted
if
emissions
of
hydrogen
chloride
from
the
source
are
projected
to
increase
background
levels
of
hydrogen
ion
equivalents
by
greater
than
20
percent.
We
are
concerned,
however,
about
the
practicability
of
implementing
this
approach
to
objectively
gauge
the
incremental
impact
of
the
combustor's
emissions
on
acidification.
The
National
Atmospheric
Deposition
Program
has
data
on
hydrogen
ion
deposition
for
200
sites
around
the
country,
but
data
may
not
be
available
for
many
hazardous
waste
combustor
locations.
See
http://
nadp.
sws.
uiuc.
edu/.
In
those
cases,
it
may
be
reasonable
for
you
either
to
use
the
data
from
the
nearest
appropriate
monitoring
station,
or
to
sample
and
analyze
rainfall
to
determine
site­
specific
deposition
rates.
Another
concern
with
this
approach
is
that
yearly
deposition
rates
recorded
by
the
National
Atmospheric
Deposition
Program
can
vary
significantly.
Although
this
could
be
addressed
by
calculating
3­
or
5­
year
average
deposition
rates,
defining
a
significant
impact
of
deposition
based
on
10
percent
or
20
percent
of
background
deposition
rates
may
still
be
problematic.
We
specifically
request
comment
on
these
approaches
to
address
acidification
of
acidsensitive
surface
waters
C.
How
Would
You
Determine
if
Your
Total
Chlorine
Emission
Rate
Meets
the
Eligibility
Requirements
Defined
by
the
National
Exposure
Standards?
Under
the
risk­
based
approach
to
establish
an
alternative
to
the
MACT
standard
for
your
total
chlorine
emission
limit,
you
would
have
to
demonstrate
that
emissions
of
total
chlorine
from
on­
site
hazardous
waste
combustors
result
in
exposure
to
the
actual
most­
exposed
individual
residing
off
site
of
a
Hazard
Index
of
less
than
or
equal
to
1.0.
(
Put
another
way,
we
are
proposing
to
establish
this
level
of
risk
as
the
national
emission
limitation,
with
the
rule
further
establishing
the
mechanisms
by
which
this
demonstration
can
be
made,
such
demonstrations
yielding
a
site­
specific
limit
for
total
chlorine.)
17
The
rule
would
also
establish
two
ways
by
which
you
could
make
this
demonstration:
by
a
look­
up
table
analysis
or
by
a
site­
specific
compliance
demonstration
(
as
explained
below).
The
look­
up
table
is
much
simpler
to
use,
but
establishes
emission
rates
that
are
quite
conservative
because
there
are
few
site­
specific
parameters
considered
and
therefore
the
model's
default
assumptions
are
conservative.
If
you
elect
not
to
comply
with
those
conservative
emission
rates,
you
may
perform
a
site­
specific
compliance
demonstration.
26
The
look­
up
table
identifies
the
total
chlorine
emission
limit
in
terms
of
a
toxicity­
weighted
HCl­
equivalent
emission
rate.
Under
the
site­
specific
compliance
demonstration
alternative,
the
total
chlorine
limit
would
also
be
expressed
as
a
toxicity
weighted
HCl­
equivalent
emission
rate
even
though
you
would
model
emissions
of
hydrogen
chloride
and
chlorine
gas
from
each
on­
site
hazardous
waste
combustor.
We
define
the
toxicity­
weighted
HCl­
equivalent
emission
rate
below..
1.
Toxicity­
Weighted
HCl­
Equivalent
Emission
Rates
Although
the
MACT
emission
standards
for
total
chlorine
are
expressed
as
a
stack
gas
emission
concentration­­
ppmv­­
we
must
use
an
emission
rate
(
e.
g.,
lb/
hr)
format
for
risk­
based
standards.
This
is
because
health
and
environmental
risk
is
related
to
the
mass
rate
of
emissions
over
time.
In
addition,
we
propose
to
use
a
toxicity­
weighted
HCl­
equivalent
emission
rate
(
HClequivalents
as
the
metric
for
the
combined
emissions
of
hydrogen
chloride
and
chlorine
gas.
The
HCl­
equivalent
emission
rate
considers
the
RfCs
of
hydrogen
chloride
and
chlorine
gas
when
calculating
the
combined
emission
rate
according
to
this
equation:

ER
tw
=

(
ER
i
x
(
RfCHCl/
RfCi))
where:
ER
tw
is
the
HC1­
equivalent
emission
rate,
lb/
hr
ER
i
is
the
emission
rate
of
HAP
i
in
lbs/
hr
RfC
i
is
the
reference
concentration
of
HAP
i
RfC
HCl
is
the
reference
concentration
of
HCl
Expressing
the
risk­
based
emission
limit
as
HCl­
equivalents
enables
you
to
use
the
equation
to
apportion
the
emission
rate
limit
between
hydrogen
chloride
and
chlorine
gas
as
you
choose.
Thus,
you
need
to
be
concerned
with
ensuring
compliance
with
the
HCl­
equivalent
emission
rate
only,
rather
than
with
emission
rates
for
hydrogen
chloride
and
chlorine
gas
individually.
Under
the
look­
up
table
analysis
discussed
below,
you
would
use
the
hydrogen
chloride
and
chlorine
gas
emission
rates
you
choose
for
each
on­
site
hazardous
waste
combustor
to
calculate
the
HCl­
equivalent
emission
rate
for
the
combustor.
You
would
sum
the
HCl­
equivalent
emission
rates
for
your
hazardous
waste
combustors.
If
you
elect
to
use
the
site­
specific
compliance
demonstration
to
document
eligibility,
you
would
model
emission
rates
of
hydrogen
chloride
and
chlorine
gas
that
you
choose
for
each
on­
site
hazardous
waste
combustor
to
document
that
the
facility
Hazard
Index
is
less
than
or
equal
to
1.0.
You
would
then
use
the
hydrogen
chloride
and
chlorine
gas
emission
rates
you
model
to
establish
an
HCl­
equivalent
emission
rate
limit
for
each
combustor.
2.
How
Would
You
Conduct
a
Look­
Up
Table
Analysis?
You
would
sum
the
HCl­
equivalent
rates
for
all
combustors,
and
compare
the
sum
to
the
appropriate
allowable
emission
rate
in
Table
XX1
of
Subpart
EEEproposed
§
63.1215.
Emission
rates
are
provided
as
a
function
of
stack
height
and
distance
to
the
nearest
property
boundary.
If
you
have
more
than
one
hazardous
waste
combustor
at
your
facility,
you
would
use
the
average
value
for
stack
height
(
i.
e.,
the
averaged
stack
heights
of
the
different
hazardous
waste
18
HCl
production
furnaces
are
not
eligible
for
the
risk­
based
total
chlorine
emission
limits
because
we
are
proposing
that
the
MACT
standard
for
total
chlorine
would
be
used
as
a
surrogate
to
control
metal
HAP.
Nonetheless,
if
you
operate
an
HCl
production
furnace
at
a
facility
where
you
would
establish
risk­
based
emission
limits
for
total
chlorine
for
other
hazardous
waste
combustors,
you
would
account
for
total
chlorine
emissions
from
the
HCl
production
furnace
in
your
risk­
based
eligibility
demonstration
for
the
other
combustors.
If,
for
example,
you
use
the
look­
up
table
to
demonstrate
eligibility,
you
would
include
the
stack
height
of
the
HCl
production
furnace
in
the
calculation
of
average
stack
height
for
your
combustors,
and
you
would
consider
whether
the
HCl
production
furnace
stack
is
the
closest
hazardous
waste
combustor
stack
to
the
property
boundary.

27
combustors
at
your
facility),
and
the
minimum
distance
between
any
hazardous
waste
combustor
stack
and
the
property
boundary.
18
If
one
or
both
of
these
values
for
stack
height
and
distance
to
nearest
property
boundary
do
not
match
the
exact
values
in
the
look­
up
table,
you
would
use
the
next
lowest
table
value.
This
would
ensure
that
the
HCl­
equivalent
emission
rate
limits
are
protective.
You
would
not
be
eligible
for
the
look­
up
table
analysis
if
your
facility
is
located
in
complex
terrain
because
the
plume
dispersion
models
used
to
calculate
the
emission
rates
are
not
applicable
to
sources
in
complex
terrain.
You
would
be
eligible
to
comply
with
the
risk­
based
alternative
HCl­
equivalent
emission
rate
limits
you
calculate
for
each
combustor
if
the
facility
HCl­
equivalent
emission
rate
limit
(
i.
e.,
the
sum
of
the
HCl­
equivalent
emission
rates
for
all
hazardous
waste
combustors)
does
not
exceed
the
appropriate
value
specified
in
the
look­
up
table.
Please
note,
however,
that
we
also
propose
to
cap
the
HCl­
equivalent
emission
rate
limits
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
at
a
level
that
ensures
that
the
current
total
chlorine
emission
standards
are
not
exceeded.
See
discussion
below
in
Section
D.
Please
note
that
the
emission
rates
provided
in
Table
XX1
are
different
from
those
provided
for
industrial
boilers
in
the
Industrial
Boiler
and
Process
Heater
MACT
rule
recently
promulgated.
This
is
because
the
key
parameters
used
by
the
SCREEN3
atmospheric
dispersion
model
to
predict
the
normalized
air
concentrations
that
EPA
used
to
establish
HCl­
equivalent
emission
rates
as
a
function
of
stack
height
and
distance
to
property
boundary
for
industrial
boilers­­
stack
diameter,
stack
exit
gas
velocity,
and
stack
exit
gas
temperature­­
are
substantially
different
for
hazardous
waste
burning
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns.
Thus,
the
maximum
HCl­
equivalent
emission
rates
for
hazardous
waste
combustors
would
generally
be
lower
than
those
EPA
established
for
industrial
boilers.
To
ensure
that
the
HCl­
equivalent
emission
rate
limits
in
a
look­
up
table
analysis
for
hazardous
waste
combustors
would
not
result
in
a
Hazard
Index
of
more
than
1.0,
we
propose
to
establish
limits
based
on
the
maximum
annual
average
normalized
air
concentrations
in
US
EPA,
"
A
Tiered
Modeling
Approach
for
Assessing
the
Risk
Due
to
Sources
of
Hazardous
Air
Pollutants,"
March
1992,
Table
1.
Those
normalized
air
concentrations
are
based
on
conservative
simulations
of
toxic
pollutant
sources
with
Gaussian
plume
dispersion
models.
The
simulations
are
conservative
regarding
factors
such
as
meteorology,
building
downwash,
plume
rise,
etc.
We
specifically
request
comment
on
whether
the
HCl­
equivalent
emission
rates
in
Table
19
When
calculating
Hazard
Index
values,
the
final
HI
value
should
be
rounded
to
one
decimal
place
given
the
uncertainties
in
the
analyses.
For
example,
an
HI
calculated
to
be
0.94
would
be
presented
as
0.9,
while
an
HI
calculated
to
be
0.96
would
be
presented
as
1.0
(
which
would
pass
the
eligibility
demonstration).
Intermediate
calculations
should
use
as
many
significant
figures
as
appropriate.

28
XX1
are
too
conservative
and
thus
have
limited
utility
because
they
apply
to
all
hazardous
waste
combustors
generically.
Alternatively,
we
could
establish
less
conservative
emission
rates
in
lookup
tables
specific
to
various
classes
of
hazardous
waste
combustors
(
e.
g.,
cement
kilns,
incinerators)
that
have
similar
stack
properties
that
affect
predicted
emissions.
We
request
comment
on
whether
industry
stakeholders
would
be
likely
to
use
the
proposed
look­
up
table
eligibility
demonstration
or
revised
look­
up
tables
tailored
to
specific
classes
of
hazardous
waste
combustors,
in
lieu
of
the
site­
specific
compliance
eligibility
demonstration.
3.
How
Would
You
Conduct
a
Site­
Specific
Compliance
Demonstration?
If
you
fail
to
demonstrate
that
your
facility
is
able
to
comply
with
the
alternative
riskbased
emission
limit
using
the
look­
up
table
approach,
you
may
choose
to
perform
a
site­
specific
compliance
demonstration.
We
are
proposing
that
you
may
use
any
scientifically­
accepted
peerreviewed
risk
assessment
methodology
for
your
site­
specific
compliance
demonstration.
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
Website
at
www.
epa.
gov/
ttn/
atw.
Your
facility
would
be
eligible
for
the
alternative
risk­
based
total
chlorine
emission
limit
if
your
site­
specific
compliance
demonstration
shows
that
the
maximum
Hazard
Index
for
hydrogen
chloride
and
chlorine
gas
emissions
from
all
on­
site
hazardous
waste
combustors
at
a
location
where
people
live
(
i.
e.,
the
maximum
actual
most
exposed
individual)
is
less
than
or
equal
to
1.0,
rounded
to
the
nearest
tenths
decimal
place
(
0.1).
19
You
would
estimate
long­
term
inhalation
exposures
for
this
individual
most
exposed
to
the
facility's
emissions
through
the
estimation
of
annual
or
multi­
year
average
ambient
concentrations.
You
would
use
site­
specific,
qualityassured
data
wherever
possible,
and
health­
protective
default
assumptions
wherever
site­
specific
data
are
not
available.
You
would
document
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.
Your
site­
specific
compliance
demonstration
need
not
assume
any
attenuation
of
exposure
concentrations
due
to
the
penetration
of
outdoor
pollutants
into
indoor
exposure
areas.
In
addition,
we
are
proposing
that
the
demonstration
need
not
assume
any
reaction
or
deposition
of
hydrogen
chloride
and
chlorine
gas
from
the
emission
point
to
the
point
of
exposure.
In
particular,
you
would
assume
that
chlorine
gas
is
not
photolyzed
to
hydrogen
chloride,
as
discussed
in
Section
B.
1
above.
If
your
site­
specific
compliance
demonstration
documents
that
the
maximum
Hazard
Index
from
your
hazardous
waste
combustors
is
less
than
or
equal
to
1.0,
you
would
establish
a
maximum
HCl­
equivalent
emission
rate
limit
for
each
combustor
using
the
hydrogen
chloride
and
chlorine
gas
emission
rates
you
modeled
in
the
site­
specific
compliance
demonstration.
Please
29
note,
however,
that
we
also
propose
to
cap
the
HCl­
equivalent
emission
rate
limits
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
at
a
level
that
ensures
that
the
current
total
chlorine
emission
standards
are
not
exceeded.
See
discussion
below
in
Section
D.
D.
What
Is
the
Rationale
for
Caps
on
the
Risk­
Based
Emission
Limits?
The
HCl­
equivalent
emission
rate
limits
would
be
capped
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
at
a
level
that
ensures
total
chlorine
emissions
do
not
exceed
the
interim
standards
provided
by
§
§
63.1203,
63.1204,
and
63.1205.
These
caps
on
the
risk­
based
emission
limits
would
ensure
that
emission
levels
do
not
increase
above
the
emission
levels
that
sources
are
currently
required
to
achieve,
thus
precluding
"
back­
sliding."
Given
the
discretionary
nature
of
section
112
(
d)
(
4),
and
the
general
purpose
of
the
section
112
(
d)
standard­
setting
process
to
lock­
in
performance
of
current
emission
control
technology,
we
think
it
appropriate
to
invoke
the
provision
in
a
manner
that
does
not
result
in
emission
increases
over
current
regulatory
levels.
We
considered
whether
to
propose
emission
caps
for
boilers
at
the
levels
allowed
by
the
RCRA
emission
standards
under
§
266.107
but
conclude
that
this
would
be
inappropriate.
This
is
because
the
RCRA
emission
standards
are
also
risk­
based
standards
but
are
based
on
risk
criteria
that
we
considered
appropriate
in
1987
when
we
proposed
those
rules.
The
risk
criteria
we
propose
today
are
substantially
different
from
those
used
to
implement
§
266.107.
For
example,
the
RfC
for
hydrogen
chloride
is
higher
now
while
the
RfC
for
chlorine
gas
is
lower.
In
addition,
we
considered
a
Hazard
Index
of
0.25
acceptable
under
the
RCRA
rule,
while
we
propose
today
a
Hazard
Index
limit
of
less
than
or
equal
to
1.0.
Because
the
risk
criteria
for
the
current
RCRA
rules
are
substantially
different
from
the
risk
criteria
we
propose
today
for
invoking
Section
112(
d)(
4),
we
do
not
believe
it
is
appropriate
to
use
the
RCRA
standards
as
a
cap
for
establishing
risk­
based
standards
under
Section
112(
d)(
4).
Capping
risk­
based
emission
limits
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
at
an
HCl­
equivalent
emission
rate
corresponding
to
the
MACT
interim
standards
would
not
increase
compliance
costs
(
by
definition).
Thus,
the
cap
would
help
ensure
that
emissions
are
protective
of
public
health
with
an
ample
margin
of
safety,
and
that
there
are
no
significant
adverse
environmental
impacts.
To
implement
the
cap,
you
would
ensure
that
the
hydrogen
chloride
and
chlorine
gas
emission
rates
you
use
to
calculate
the
HCl­
equivalent
emission
rate
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
would
not
result
in
total
chlorine
emission
concentrations
exceeding
the
standards
provided
by
§
§
63.1203,
63.1204,
and
63.1205.
E.
What
Would
Your
Risk­
Based
Eligibility
Demonstration
Contain?
To
enable
regulatory
officials
to
review
and
approve
the
results
of
your
risk­
based
demonstration,
you
would
include
the
following
information,
at
a
minimum:
(
1)
identification
of
each
hazardous
waste
combustor
combustion
gas
emission
point
(
e.
g.,
generally,
the
flue
gas
stack);
(
2)
the
maximum
capacity
at
which
each
combustor
will
operate,
and
the
maximum
rated
capacity
for
each
combustor,
using
the
metric
of
stack
gas
volume
emitted
per
unit
of
time,
as
well
as
any
other
metric
that
is
appropriate
for
the
combustor
(
e.
g.,
million
Btu/
hr
heat
input
for
boilers;
tons
of
dry
raw
material
feed/
hour
for
cement
kilns);
(
3)
stack
parameters
for
each
combustor,
including,
but
not
limited
to
stack
height,
stack
area,
stack
gas
temperature,
and
stack
gas
exit
velocity;
(
4)
plot
plan
showing
all
stack
emission
points,
nearby
residences,
and
property
20
Since
the
Title
V
permitting
authority
is
delegated
to
States
in
virtually
all
instances,
the
permit
limit
would
thus
be
issued
as
a
matter
of
State
authority
(
generally
in
parallel
with
a
delegation
of
Section
112
authority
pursuant
to
CAA
Section
112(
l)),
and
be
reviewable
only
in
State
courts.

30
boundary
line;
(
5)
identification
of
any
stack
gas
control
devices
used
to
reduce
emissions
from
each
combustor;
(
6)
identification
of
the
RfC
values
used
to
calculate
the
HCl­
equivalent
emissions
rate;
(
7)
calculations
used
to
determine
the
HCl­
equivalent
emission
rate
as
prescribed
above;
(
8)
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns,
calculations
used
to
determine
that
the
HCl­
equivalent
emission
rate
limit
for
each
combustor
does
not
exceed
the
standards
for
total
chlorine
at
§
§
63.1203,
63.1204,
and
63.1205;
and
(
9)
the
HCl­
equivalent
emission
rate
limit
for
each
hazardous
waste
combustor
that
you
will
certify
in
the
Documentation
of
Compliance
required
under
§
63.1211(
d)
that
you
will
not
exceed,
and
the
limits
on
the
operating
parameters
specified
under
§
63.1209(
o)
that
you
will
establish
in
the
Documentation
of
Compliance.
If
you
use
the
look­
up
table
analysis
to
demonstrate
that
your
facility
is
eligible
for
the
risk­
based
alternative
for
the
total
chlorine
emission
limit,
your
eligibility
demonstration
would
also
contain,
at
a
minimum,
the
following:
(
1)
calculations
used
to
determine
the
average
stack
height
of
on­
site
hazardous
waste
combustors;
(
2)
identification
of
the
combustor
stack
with
the
minimum
distance
to
the
property
boundary
of
the
facility;
(
3)
comparison
of
the
values
in
the
look­
up
table
to
your
maximum
HCl­
equivalent
emission
rate.
If
you
use
a
site­
specific
compliance
demonstration
to
demonstrate
that
your
facility
is
eligible
for
the
risk­
based
alternative
for
the
total
chlorine
emission
limit,
your
eligibility
demonstration
would
also
contain,
at
a
minimum,
the
following:
(
1)
identification
of
the
risk
assessment
methodology
used;
(
2)
documentation
of
the
fate
and
transport
model
used;
and
(
3)
documentation
of
the
fate
and
transport
model
inputs,
including
the
stack
parameters
listed
above
converted
to
the
dimensions
required
for
the
model.
In
addition,
you
would
include
all
of
the
following
that
apply:
(
1)
meteorological
data;
(
2)
building,
land
use,
and
terrain
data;
(
3)
receptor
locations
and
population
data;
and
(
4)
other
facility­
specific
parameters
input
into
the
model.
Your
demonstration
would
also
include:
(
1)
documentation
of
the
fate
and
transport
model
outputs;
(
2)
documentation
of
any
exposure
assessment
and
risk
characterization
calculations;
and
(
3)
documentation
of
the
predicted
Hazard
Index
for
HCl­
equivalents
and
comparison
to
the
limit
of
less
than
or
equal
to
1.0.
F.
When
Would
You
Complete
and
Submit
Your
Eligibility
Demonstration
You
would
be
required
to
submit
your
eligibility
demonstration
to
the
permitting
authority
for
review
and
approval.
20
In
addition
you
would
submit
an
electronic
copy
of
the
demonstration
to
REAG@
EPA.
GOV
(
preferably)
or
a
hard
copy
to:
U.
S.
EPA,
Risk
and
Exposure
Assessment
Group,
Emission
Standards
Division
(
C404­
01),
Attn:
Group
Leader,
Research
Triangle
Park,
North
Carolina
27711.
Requiring
prior
approval
of
these
eligibility
demonstrations
is
warranted
because
hazardous
waste
combustor
may
feed
chlorine
at
high
feedrates
which
may
result
in
emissions
of
hydrogen
chloride
and
chlorine
gas
that
approach
or
exceed
the
RfCs
(
i.
e.,
absent
compliance
with
either
the
MACT
standards
or
the
section
112(
d)(
4)
risk­
based
standards).
Thus,
prior
21
Please
note
that,
if
your
eligibility
demonstration
is
not
approved
prior
to
the
compliance
date,
a
request
to
extend
the
compliance
date
to
enable
you
to
undertake
measures
to
comply
with
the
MACT
standards
for
total
chlorine
will
not
be
approved
unless
you
made
a
good
faith
effort
to
submit
a
complete,
accurate,
and
timely
eligibility
demonstration
and
to
respond
to
concerns
raised
by
the
permitting
authority
or
U.
S.
EPA.

31
approval
of
alternative
HCl­
equivalent
emission
rate
limits
is
warranted
to
ensure
that
emissions
are
protective
with
an
ample
margin
of
safety.
1.
Existing
Sources
If
you
operate
an
existing
source,
you
must
be
in
compliance
with
the
emission
standards
on
the
compliance
date.
Consequently,
if
you
elect
to
comply
with
the
alternative
risk­
based
emission
rate
limit
for
total
chlorine,
you
must
have
completed
the
eligibility
demonstration
and
received
approval
from
your
delegated
permitting
authority
by
the
compliance
date.
You
would
submit
documentation
supporting
your
eligibility
demonstration
not
later
than
12
months
prior
to
the
compliance
date.
Your
permitting
officials
will
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.
If
your
permitting
authority
has
not
approved
your
eligibility
demonstration
to
comply
with
a
risk­
based
HCl­
equivalent
emission
rate(
s)
by
the
compliance
date,
you
must
comply
with
the
MACT
emission
standards
for
total
chlorine
gas
under
§
§
63.1203A,
63.1204(
A),
63.1205A,
63.1216,
and
63.1217.21
2.
New
Sources
If
you
operate
a
source
that
is
not
an
existing
source
and
that
becomes
subject
to
Subpart
EEE,
you
must
comply
with
the
MACT
emission
standards
for
total
chlorine
unless
and
until
your
eligibility
demonstration
has
been
approved
by
the
permitting
authority.
If
you
operate
a
new
or
reconstructed
source
that
starts
up
before
the
effective
date
of
the
emission
standards
proposed
today,
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
the
effective
date
of
the
emission
standards
proposed
today
(
and
thus
becomes
subject
to
emission
standards
applicable
to
major
sources,
including
the
standard
for
total
chlorine),
you
would
be
required
to
comply
with
the
emission
standards
under
§
§
63.1216
and
63.1217
until
your
eligibility
demonstration
is
completed,
submitted,
and
approved
by
your
permitting
authority.
If
you
operate
a
new
or
reconstructed
source
that
starts
up
after
the
effective
date
of
the
emission
standards
proposed
today,
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
after
the
effective
date
of
the
emission
standards
proposed
today
(
and
thus
becomes
subject
to
emission
standards
applicable
to
major
sources
including
the
standard
for
total
chlorine),
you
would
be
required
to
comply
with
the
emission
standards
under
§
§
63.1216
and
32
63.1217
until
your
eligibility
demonstration
is
completed,
submitted,
and
approved
by
your
permitting
authority.
FG.
How
Would
the
Risk­
Based
HCl­
Equivalent
Emission
Rate
Limit
Be
Implemented?
Upon
approval
by
the
permitting
authority
of
your
eligibility
demonstration,
the
HClequivalent
emission
rate
limit
established
in
the
demonstration
for
your
hazardous
waste
combustor(
s)
becomes
the
applicable
emission
limit
for
total
chlorine
in
lieu
of
the
MACT
standard
for
total
chlorine.
1.
What
Are
the
Testing
and
Monitoring
Requirements?
To
ensure
compliance
with
the
alternative
HCl­
equivalent
emission
rate
limit
for
your
combustor(
s),
you
would
conduct
performance
testing
as
required
for
the
MACT
standards
and
establish
limits
on
the
same
operating
parameters
that
apply
to
sources
complying
with
the
MACT
standards
for
total
chlorine
under
§
63.1209(
o).
You
would
establish
and
comply
with
these
operating
parameter
limits
just
as
you
would
establish
and
comply
with
the
limits
for
the
MACT
emission
standard
for
total
chlorine,
with
the
exception
of
the
chlorine
feedrate
limit,
as
discussed
below.
For
example,
existing
sources
would
establish
these
limits
in
the
Documentation
of
Compliance
required
under
§
63.1211(
c)
and
begin
complying
with
them
not
later
than
the
compliance
date.
Existing
sources
would
also
revise
the
operating
limits
as
necessary
based
on
the
initial
comprehensive
performance
test
and
begin
complying
with
the
revised
operating
limits
not
later
than
when
the
Notification
of
Compliance
is
postmarked,
as
required
under
§
§
63.1207(
j)
and
63.1210(
b).
The
limit
on
chlorine
feedrate
required
under
§
63.1209(
o)(
1)
would
be
established
differently
to
ensure
compliance
with
the
HCl­
equivalent
emission
rate
limit
rather
than
the
total
chlorine
emission
standard.
To
ensure
that
facility­
wide
hazardous
waste
combustor
emissions
of
HCl­
equivalents
result
in
exposures
equivalent
to
a
Hazard
Index
of
less
than
or
equal
to
1.0,
the
feedrate
limit
for
chlorine
would
be
established
as
the
average
of
the
test
run
averages
and
the
averaging
period
for
compliance
would
be
one
year.
A
yearly
rolling
average
is
appropriate
for
risk­
based
emission
limits
rather
than
the
12­
hour
rolling
average
applicable
to
the
MACT
standards
because
the
risk­
based
emission
limit
is
based
on
chronic
exposure.
As
discussed
in
Section
B.
2.
e
above,
although
we
conclude
that
the
chronic
exposure
Hazard
Index
would
always
be
higher
and
thus
be
the
basis
for
the
total
chlorine
emission
rate
limit,
we
still
must
be
concerned
about
acute
exposure
attributable
to
short­
term
emission
rates
higher
than
the
maximum
average
emission
rate
limit.
For
example,
the
annual
average
limit
on
chlorine
(
i.
e.,
total
chlorine
and
chloride)
feedrate
would
allow
a
source
to
feed
very
high
levels
of
chlorine
for
short
periods
of
time,
potentially
resulting
in
exceedances
of
the
acute
exposure
Hazard
Index
based
the
AEGL­
1
values
for
hydrogen
chloride
and
chlorine
gas.
We
specifically
request
comment
on
how
a
short­
term
limit
on
chlorine
feedrate
could
be
established
for
each
hazardous
waste
combustor
to
ensure
that
the
acute
exposure
Hazard
Index
is
less
than
or
equal
to
1.0.
One
approach
would
be
for
you
to
extrapolate
from
the
chlorine
feedrate
during
the
comprehensive
performance
test
to
the
feedrate
projected
to
achieve
emission
rates
of
hydrogen
22
We
also
request
comment
on
whether
extrapolation
of
the
chlorine
feedrate
should
be
allowed
to
100%
of
the
Hazard
Index
limit
of
1.0,
or
whether
a
more
conservative
approach
of
limited
extrapolation
to
a
fraction
of
the
Hazard
Index
(
e.
g.,
0.8)
would
be
warranted,
given
the
uncertainties
inherent
in
projecting
emissions
from
extrapolated
feedrates.

23
We
request
comment
on
whether
the
system
removal
efficiency
a
cement
kiln
demonstrates
during
a
performance
test
because
of
the
alkalinity
of
the
raw
material
is
reasonably
indicative
of
the
system
removal
efficiency
it
routinely
achieves
(
i.
e.,
is
the
system
removal
efficiency
reasonably
reproducible).

24
We
would
use
the
normalized
maximum
1­
hour
average
concentrations
in
US
EPA,
"
A
Tiered
Modeling
Approach
for
Assessing
the
Risk
Due
to
Sources
of
Hazardous
Air
Pollutants,"
March
1992,
Table
2.

25
Even
though
Method
26/
26A
may
bias
total
chlorine
emission
measurements
low
for
cement
kilns
for
reasons
discussed
in
the
text,
it
is
appropriate
to
allow
compliance
with
the
33
chloride
and
chlorine
gas
that
result
in
an
acute
exposure
Hazard
Index
of
1.0.22
This
feedrate
would
be
a
1­
hour
average
feedrate
limit.
This
approach
uses
the
reasonable
assumption
that
there
is
a
proportional
relationship
between
chlorine
feedrate
and
the
emission
rate
of
hydrogen
chloride
and
chlorine
gas.
To
extrapolate
feedrates,
you
would
consider
the
system
removal
efficiency
achieved
during
the
performance
test
for
sources
equipped
with
wet
or
dry
acid
gas
scrubbers
and
for
cement
kilns.
23
Other
sources
would
assume
a
zero
system
removal
efficiency
because
any
removal
efficiency
that
may
be
measured
would
be
incidental
and
not
reproducible.
The
approach
discussed
above
would
be
applicable
if
you
use
the
site­
specific
compliance
eligibility
demonstration.
If
you
use
the
look­
up
table
for
your
eligibility
demonstration,
an
alternative
approach
would
be
needed
to
establish
a
short­
term
chlorine
feedrate
limit.
One
approach
would
be
to
establish
a
look­
up
table
for
maximum
1­
hour
average
HCl­
equivalents
based
on
acute
exposure.
Acute
exposure
HCl­
equivalents
would
be
calculated
using
the
AEGL­
1
values
for
hydrogen
chloride
and
chlorine
gas,
and
the
look­
up
table
of
acute
exposure
maximum
emission
rate
limits
would
be
based
on
normalized
air
concentrations
for
maximum
1­
hour
average
ground
level
concentrations.
24
You
would
extrapolate
the
chlorine
feedrate
from
the
level
achieved
during
the
comprehensive
performance
test
to
a
level
that
would
not
exceed
the
acute
exposure
HCl­
equivalent
emission
rate
limit
for
each
combustor
provided
in
the
look­
up
table.
This
feedrate
would
be
a
1­
hour
average
feedrate
limit.
We
specifically
request
comment
on
these
approaches
to
establish
a
short­
term
limit
on
the
feedrate
of
total
chlorine
and
chloride
to
ensure
that
the
acute
exposure
Hazard
Index
for
hydrogen
chloride
and
chlorine
gas
is
less
than
or
equal
to
1.0.
2.
What
Test
Methods
Would
You
Use?
Although
you
would
comply
with
the
MACT
standard
for
total
chlorine
using
stack
Method
26/
26A,
certain
sources
would
not
be
allowed
to
use
that
method
to
demonstrate
compliance
with
the
risk­
based
HCl­
equivalent
emission
rate
limit.
25
Cement
kilns
and
sources
technology­
based
MACT
emission
standards
for
total
chlorine
using
that
method.
Because
the
MACT
standards
are
developed
using
data
obtained
using
Method
26/
26A,
allowing
that
method
for
compliance
will
achieve
reductions
in
total
chlorine
emissions.
For
the
same
reason,
it
would
be
inappropriate
to
require
compliance
with
unbiased
methods
because
the
average
of
the
best
performing
sources
might
not
be
able
to
achieve
the
standard.

26
USEPA,
"
Draft
Technical
Support
Document
for
HWC
MACT
Replacement
Standards,
Volume
III:
Selection
of
MACT
Standards
and
Technologies,"
March
2004.

34
equipped
with
a
dry
acid
gas
scrubber
should
use
EPA
Method
320/
321
or
ASTM
D
6735­
01
to
measure
hydrogen
chloride,
and
the
back­
half
(
caustic
impingers)
of
Method
26/
26A
to
measure
chlorine
gas.
Incinerators,
boilers,
and
lightweight
aggregate
kilns
should
use
EPA
Method
320/
321
or
ASTM
D
6735­
01
to
measure
hydrogen
chloride,
and
Method
26/
26A
to
measure
total
chlorine,
and
calculate
chlorine
gas
by
difference
if:
(
1)
the
bromine/
chlorine
ratio
in
feedstreams
is
greater
than
5
percent;
or
(
2)
the
sulfur/
chlorine
ratio
in
feedstreams
is
greater
than
50
percent.
a.
Method
26/
26A
Has
a
Low
Bias
for
Hydrogen
Chloride
in
Certain
Situations.
Method
26/
26A
has
a
low
bias
for
hydrogen
chloride
for
sources
that
emit
particulate
matter
than
can
adsorb
hydrogen
chloride:
cement
kilns
and
sources
equipped
with
a
dry
acid
gas
scrubber.
Particulate
matter
caught
by
the
Method
26/
26A
filter
scrubs
hydrogen
chloride
from
the
sample
gas,
and
can
result
in
measurements
that
are
biased
low
by
2
to
30
times.
26
Chlorine
gas
is
not
adsorbed
so
that
chlorine
gas
emissions
are
not
biased
by
this
mechanism.
b.
Method
26/
26A
Can
Have
a
Low
Bias
for
Chlorine
Gas
and
a
High
Bias
for
Hydrogen
Chloride,
but
Has
No
Bias
for
Total
Chlorine.
Method
26/
26A
also
has
a
low
bias
for
chlorine
and
a
high
bias
for
hydrogen
chloride
when
bromine
is
present
at
significant
levels.
Bromine
has
a
strong
effect
on
the
bias.
Although
the
various
interhalogen
reactions
are
extremely
complex
and
may
depend
on
a
variety
of
system
parameters,
it
appears
that
each
bromine
molecule
can
react
with
a
chlorine
molecule
in
the
acidic
impingers
of
Method
26/
26A
where
hydrogen
chloride
is
captured,
converting
the
chlorine
to
chloride
ions
which
are
reported
as
hydrogen
chloride.
Total
chlorine
measurements
(
i.
e.,
hydrogen
chloride
and
chlorine
gas,
combined,
reported
as
HCl
equivalents),
however,
are
not
affected.
To
minimize
this
bias,
we
propose
to
require
sources
that
have
a
bromine/
chlorine
feedrate
exceeding
5
percent
to
use
alternative
methods
discussed
below.
Given
the
strong
bias
that
bromine
can
have
on
M26/
26A
measurements,
we
believe
a
5
percent
limit
on
the
ratio
is
within
the
range
of
reasonable
values
that
we
could
select.
We
specifically
request
comment
on
this
or
other
approaches
to
minimize
the
bromine
bias.
Method
26/
26A
also
has
a
low
bias
for
chlorine
and
a
high
bias
for
hydrogen
chloride
when
sulfur
is
present
at
substantial
levels
relative
to
the
levels
of
chlorine.
The
capture
of
chlorine
in
the
acidic
impingers
that
collect
hydrogen
chloride
has
been
shown
to
rapidly
increase
when
the
ratio
of
SO2/
HCl
(
both
expressed
in
ppmv)
exceeds
0.5.
Again,
total
chlorine
measurements
are
not
biased.
To
minimize
this
bias,
we
believe
that
a
50
percent
limit
on
the
ratio
of
the
sulfur/
chlorine
feedrate
is
within
the
range
of
reasonable
values
that
we
could
select.
We
specifically
request
comment
on
this
or
other
approaches
to
minimize
the
sulfur
dioxide
bias.
35
c.
Unbiased
Methods
Are
Available.
The
Agency
recently
developed
three
methods
for
hydrogen
chloride
in
the
context
of
the
Portland
Cement
MACT
rule
for
purposes
of
area
source
determinations:
Methods
320,
321,
and
322.
Although
M322
(
GFCIR,
Gas
Filter
Correlation
Infra­
Red)
is
easier
to
use
and
less
expensive
than
M320/
M321
(
FTIR,
Fourier
Transform
Infra­
Red),
the
Agency
did
not
promulgated
M322
in
the
final
Portland
Cement
MACT
rule
because
of
accuracy
concerns
resulting
from
emissions
sampling
of
lime
manufacturing
kilns
in
the
context
of
developing
the
Lime
Manufacturing
MACT
rule.
The
Agency
has
also
adopted
an
American
Society
of
Testing
and
Materials
(
ASTM)
standard
for
measuring
hydrogen
chloride
emissions:
ASTM
D
6735­
01.
This
method
(
and
M321)
is
allowed
for
area
source
determinations
under
the
Lime
Manufacturing
MACT
rule.
69
FR
394
(
Jan.
5,
2004).
The
method
is
an
impinger
method,
like
M26/
26A,
but
with
several
improvements.
For
example,
the
method
uses
a
rejection
probe
(
i.
e.,
the
probe
is
directed
counter
to
the
gas
flow),
the
filter
is
heated
to
minimize
adsorption
of
hydrogen
chloride
on
particulate
matter
that
may
catch
on
the
filter,
glassware
must
be
conditioned,
and
improved
quality
assurance/
quality
control
procedures
are
prescribed.
GH.
How
Would
You
Ensure
that
Your
Facility
Remains
Eligible
for
the
Risk­
Based
Emission
Limit?
1.
Changes
Over
Which
You
Have
Control
Changes
in
design,
operation,
or
maintenance
of
a
hazardous
waste
combustor
that
may
affect
the
rate
of
emissions
of
HCl­
equivalents
from
the
combustor
are
subject
to
the
requirements
of
§
63.1206(
b)(
5).
If
you
change
the
information
documented
in
the
demonstration
of
eligibility
for
the
HClequivalent
emission
rate
limit
which
is
used
to
establish
the
HCl­
equivalent
emission
rate
limit,
you
would
be
subject
to
the
following
procedures.
a.
Changes
that
Would
Decrease
the
Allowable
HCl­
Equivalent
Emission
Rate
Limit.
If
you
plan
to
make
a
change
that
would
decrease
the
allowable
HCl­
equivalent
emission
rate
limit
documented
in
your
eligibility
demonstration,
you
would
comply
with
§
63.1206(
b)(
5)(
i)(
A­
C)
regarding
notifying
the
permitting
authority
of
the
change,
submitting
a
comprehensive
performance
test
schedule
and
test
plan,
comprehensive
performance
testing,
and
restriction
on
burning
hazardous
waste
prior
to
submitting
a
revised
Notification
of
Compliance.
An
example
of
a
change
that
would
decrease
the
allowable
HCl­
equivalent
emission
rate
limit
is
location
of
the
property
boundary
closer
to
the
nearest
hazardous
waste
combustor
stack
when
using
the
look­
up
table
to
make
the
eligibility
demonstration.
b.
Changes
that
Would
Not
Decrease
the
Allowable
HCl­
Equivalent
Emission
Rate
Limit.
If
you
determine
that
a
change
would
not
decrease
the
allowable
HCl­
equivalent
emission
rate
limit
documented
in
your
eligibility
demonstration,
you
would
document
the
change
in
the
operating
record
upon
making
such
change.
If
the
change
would
increase
your
allowable
HClequivalent
emission
rate
limit
and
you
elect
to
establish
a
higher
HCl­
equivalent
limit,
you
must
submit
a
revised
eligibility
demonstration
for
review
and
approval.
Upon
approval
of
the
revised
eligibility
demonstration,
you
must
comply
with
§
63.1206(
b)(
5)(
i)(
A)(
2),
(
B),
and
(
C)
regarding
submitting
a
comprehensive
performance
test
schedule
and
test
plan,
comprehensive
performance
testing,
and
restriction
on
burning
hazardous
waste
prior
to
submitting
a
revised
Notification
of
27
Trinity
Consultants,
"
Analysis
of
HCl/|
Cl2
Emissions
from
Cement
Kilns
for
112(
d)(
4)
Consideration
in
the
HWC
MACT
Replacement
Standards,"
September
17,
2003.

36
Compliance.
2.
Changes
Over
Which
You
Do
Not
Have
Control
Over
time,
factors
and
information
over
which
you
do
not
have
control
and
which
you
use
to
make
your
eligibility
demonstration
may
change.
For
example,
if
you
use
a
site­
specific
compliance
demonstration,
individuals
may
locate
within
the
area
impacted
by
emissions
such
that
the
most
exposed
individual
may
be
exposed
to
higher
ground
level
concentrations
than
previously
estimated.
This
could
lower
your
allowable
HCl­
equivalent
emission
rate
limit.
Consequently,
you
would
be
required
to
review
the
documentation
you
use
in
your
eligibility
demonstration
every
five
years
on
the
anniversary
of
the
comprehensive
performance
test
and
submit
for
review
with
the
test
plan
either
a
certification
that
the
information
used
in
your
eligibility
demonstration
has
not
changed
in
a
manner
that
would
decrease
the
allowable
HClequivalent
emission
rate
limit,
or
a
revised
eligibility
demonstration
for
a
revised
HCl­
equivalent
emission
rate
limit.
H
If
you
determine
that
you
cannot
demonstrate
compliance
with
a
lower
allowable
HClequivalent
emission
rate
limit
during
the
(
subsequent)
comprehensive
performance
test
because
you
cannot
complete
changes
to
the
design
or
operation
of
the
source
prior
to
the
test,
you
may
request
that
the
permitting
authority
grant
you
additional
time
as
necessary
to
make
those
changes,
not
to
exceed
three
years.
I.
Request
for
Comment
on
an
Alternative
Approach:
Risk­
Based
National
Emission
Standards
As
noted
earlier,
another
approach
to
implement
section
112(
d)(
4)
 
and
one
EPA
has
used
in
past
MACT
rules
 
would
be
to
establish
national
emission
standards
for
each
source
category
to
ensure
that
the
emissions
from
each
source
within
the
category
are
protective
of
public
health
with
an
ample
margin
of
safety
(
and
do
not
pose
adverse
environmental
impacts).
Under
this
approach,
dispersion
modeling
of
representative
worst­
case
sources
(
or
all
sources)
within
a
category
would
be
used
to
identify
an
emission
level
that
meets
the
section
112(
d)(
4)
criteria
for
all
sources
within
the
category.
Thus,
the
same
risk­
based
national
emission
standard
would
be
established
for
each
source
in
each
source
category
under
this
approach,
rather
than
the
approach
we
discuss
above
of
establishing
a
national
exposure
standard
based
on
a
uniform
level
of
protection
that
you
would
use
to
establish
a
site­
specific
emission
limit.
The
approach
of
establishing
a
risk­
based
national
emission
standard
for
a
source
category
has
the
advantage
of
being
less
burdensome
to
implement
both
for
the
regulated
community
and
regulatory
authorities.
It
is
also
more
consistent
with
the
idea
of
a
uniform
national
standard.
It
has
the
disadvantage,
however,
of
requiring
documentation
"
up
front"
to
support
the
proposed
emission
standards.
EPA
does
not
have
the
time,
data,
or
resources
to
conduct
the
analyses
required
to
support
this
approach.
The
Cement
Kiln
Recycling
Coalition
(
CKRC),
however,
has
submitted
documentation
supporting
a
national
risk­
based
emission
standard
for
total
chlorine
for
cement
kilns.
27
CKRC
uses
normalized
air
concentrations
from
ISC­
PRIME
and
ISCST3
to
estimate
maximum
annual
37
average
and
maximum
1­
hour
average
off­
site
ground
level
concentrations
of
hydrogen
chloride
and
chlorine
gas
for
each
source.
CKRC
assumes
that
each
kiln
emits
total
chlorine
at
130
ppmv,
the
current
Interim
Standard,
and
that
emissions
of
hydrogen
chloride
and
chlorine
gas
partition
at
the
same
ratio
as
measured
during
the
most
recent
compliance
test.
The
analysis
indicates
that
the
facility
Hazard
Index
for
1­
hour
exposures
was
below
0.2
for
the
kilns
at
all
facilities,
and
the
facility
Hazard
Index
for
long­
term
exposures
was
below
0.2
for
the
kilns
at
8
of
14
facilities.
Emissions
from
kilns
at
the
remaining
6
facilities
can
potentially
result
in
facility
Hazard
Index
values
up
to
0.7.
Notwithstanding
that
CKRC
followed
the
guidance
we
suggested
to
identify
a
section
112(
d)(
4)
risk­
based
emission
standard
for
a
source
category,
we
conclude
that
establishing
a
stack
gas
concentration­
based
total
chlorine
standard
of
130
ppmv
may
not
be
protective
with
an
ample
margin
of
safety.
Even
though
the
highest
Hazard
Index
for
any
facility
in
the
category
is
below
the
maximum
HI
of
less
than
1.0,
the
Hazard
Index
value
for
a
facility
could
increase
even
though
sources
do
not
exceed
an
emission
standard
of
130
ppmv.
This
is
because
the
Hazard
Index
is
affected
by
the
mass
emission
rate
(
e.
g.,
lb/
hr)
of
hydrogen
chloride
and
chlorine
gas
individually.
Thus
the
Hazard
Index
could
increase
from
the
values
CKRC
has
calculated
even
though
each
source
complies
with
a
130
ppmv
total
chlorine
emission
standard
given
that:
(
1)
the
RfC
for
chlorine
gas
is
100
times
lower
than
the
RfC
for
hydrogen
chloride;
(
2)
the
partitioning
of
total
chlorine
between
hydrogen
chloride
and
chlorine
gas
could
change
so
that
a
greater
portion
is
emitted
as
chlorine;
and
(
3)
the
mass
emission
rate
of
hydrogen
chloride
and
chlorine
gas
would
increase
if
the
stack
gas
flowrate
increases.
Because
of
these
concerns,
the
more
appropriate
metric
for
a
risk­
based
standard
for
total
chlorine
would
be
the
toxicity­
weighted
HCl­
equivalent
emission
rate
discussed
above
in
Section
C.
1.
To
achieve
our
dual
objective
of
establishing
a
protective
risk­
based
emission
standard
expressed
as
a
toxicity­
weighted
HCl­
equivalent
emission
rate
(
lb/
hr)
and
ensuring
that
the
standard
does
not
allow
total
chlorine
emission
concentrations
(
ppmv)
higher
than
the
current
interim
standard
of
130
ppmv,
we
propose
that
thean
HCl­
equivalent
emission
rate
limit
be
established
as
follows:
that
is
achievable
by
all
cement
facilities.
(
1)
calculate
theThis
would
be
an
HCl­
equivalent
emission
rate
for
each
source
assuming
stack
gas
concentrations
for
total
chlorine
of
130
ppmv
and
partitioning
betweenwhich
on­
site
cement
kiln
emissions
of
hydrogen
chloride
and
chlorine
gas
and
maximum
stack
gas
flowrates
achieveddo
not
exceed
a
Hazard
Index
of
1.0.
To
make
this
determination,
facilities
would
assume
that
emissions
of
hydrogen
chloride
and
chlorine
gas
partition
at
the
same
ratio
as
measured
during
the
most
recent
compliance
test;
and
(
2)
establish
the
national
emission
standard
as
the
lowest
toxicity­
weighted
HCl­
equivalent
emission
rate
for
any
source
in
the
category.
Calculating.
Finally,
the
HCl­
equivalent
emission
rate
for
each
source
assuminglimit
would
be
capped,
if
necessary,
at
a
stack­
gas
concentration
forlimit
that
ensures
that
total
chlorine
of
130
ppmv
is
appropriate
in
the
first
step
because
CKRC
has
already
apportioned
total
chlorine
between
hydrogen
chloride
and
chlorine
gas
for
each
source
and
determined
that
a
facility
Hazard
Index
of
less
than
or
equal
to
1.0
would
not
be
exceeded
at
an
emission
concentration
ofs
for
each
kiln
do
not
exceed
130
ppmv
for
total
chlorine.
.
28
See
63
FR
at
14196
(
March
24,
1998).

29
For
the
same
reasons,
HCl­
equivalent
emission
rates
that
CRRC
may
use
in
an
eligibility
demonstration
for
the
source
category
would
be
biased
conservatively
high.

38
If
this
information
and
supporting
documentation
is
provided
to
us,
we
would
promulgate
a
toxicity­
weighted
HCl­
equivalent
emission
rate
that
would
be
applicable
to
cement
kilns.
Please
note,
however,
there
are
two
other
factors
that
may
affect
applicability
of
a
riskbased
standard
(
or
site­
specific
emission
limits)
for
total
chlorine
for
cement
kilns
(
and
other
hazardous
waste
combustors):
(
1)
whether
and
how
we
address
the
potential
for
acidification
of
acid­
sensitive
surface
waters;
and
(
2)
our
mandate
under
RCRA
to
ensure
protection
of
human
health
and
the
environment
which
would
include
consideration
of
background
levels
of
respiratory
irritants
potentially
resulting
in
site­
specific
emission
limits
more
stringent
than
any
section
112(
d)(
4)­
based
emission
limits
or
standards
that
may
be
promulgated.
On
a
related
matter,
we
evaluated
whether
using
hydrogen
chloride
and
chlorine
gas
emissions
data
obtained
with
stack
sampling
Method
26/
26A
to
project
hydrogen
chloride
and
chlorine
gas
emissions
in
CKRC's
analysis
compromised
the
results.
Method
26/
26A
is
known
to
underestimate
hydrogen
chloride
emissions
from
cement
kilns.
28
We
discuss
above
in
Section
F.
2
concerns
about
Method
26/
26A
and
the
rationale
for
proposing
to
require
sources
to
use
methods
other
than
Method
26/
26A
to
measure
emissions
of
hydrogen
chloride
and
chlorine
gas
for
compliance
with
risk­
based
standards.
Briefly,
Method
26/
26A
results
for
hydrogen
chloride
are
biased
low
for
cement
kilns,
although
results
for
chlorine
gas
are
unaffected.
Even
though
CKRC
used
Method
26A
results
to
apportion
the
130
ppmv
total
chlorine
assumed
emissions
between
hydrogen
chloride
and
chlorine
gas
for
each
source,
the
calculated
Hazard
Index
values
are
not
compromised.
Given
that
the
hydrogen
chloride
emission
levels
are
biased
low,
the
chlorine
gas/
hydrogen
chloride
ratio
that
CKRC
used
to
apportion
the
130
ppmv
total
chlorine
emissions
between
chlorine
gas
and
hydrogen
chloride
emissions
for
each
source
is
biased
high.
Thus,
CKRC
projected
chlorine
gas
emissions
that
are
biased
high
and
hydrogen
chloride
emissions
that
are
biased
low.
These
biases
result
in
calculating
conservative
(
i.
e.,
higher
than
actual)
Hazard
Index
values
because
the
health
threshold
values
are
lower
for
chlorine
gas
than
for
hydrogen
chloride.
29
Thus,
actual
Hazard
Index
values
at
an
emission
level
of
130
ppmv
total
chlorine
would
be
lower
than
those
that
CKRC
calculated.
39
§
63.1215
What
are
the
alternative
risk­
based
standards
for
total
chlorine?
(
a)
General.
You
may
establish
and
comply
with
site­
specific,
risk­
based
emission
limits
for
total
chlorine
under
the
procedures
prescribed
in
this
section.
You
may
comply
with
these
risk­
based
emission
limits
in
lieu
of
the
emission
standards
for
total
chlorine
provided
under
§
§
63.1203A,
63.1204A,
63.1205A,
63.1216,
and
63.1217
of
this
chapter
after
review
and
approval
by
the
permitting
authority.
To
identify
and
comply
with
the
limits,
you
must:
(
1)
Identify
hydrogen
chloride
and
chlorine
gas
emission
rates
for
each
on­
site
hazardous
waste
combustor.
You
may
select
hydrogen
chloride
and
chlorine
gas
emission
rates
as
you
choose
to
demonstrate
eligibility
for
the
total
chlorine
standards
under
this
section,
except
as
provided
by
paragraph
(
b)(
4)
of
this
section;
(
2)
Perform
an
eligibility
demonstration
to
determine
if
your
HCl­
equivalent
emission
rate
limits
meet
the
national
exposure
standards,
as
prescribed
by
paragraphs
(
b)
and
(
c)
of
this
section;
(
3)
Submit
your
eligibility
demonstration
for
review
and
approval,
as
prescribed
by
paragraph
(
d)
of
this
section;
(
4)
Demonstrate
compliance
with
the
HCl­
equivalent
emission
rate
limits,
as
prescribed
by
the
testing
and
monitoring
requirements
under
paragraph
(
e)
of
this
section;
and
(
5)
Comply
with
the
requirements
for
changes,
as
prescribed
by
paragraph
(
f)
of
this
section.
(
b)
HCl­
equivalent
emission
rates.
(
1)
You
must
establish
a
total
chlorine
limit
for
each
hazardous
waste
combustor
as
an
HCl­
equivalent
emission
rate.
(
2)
You
must
calculate
the
toxicity­
weighted
HCl­
equivalent
emission
rate
for
each
combustor
as
follows:

ER
tw
=

(
ER
i
x
(
RfCHCl/
RfCi))
where:
ER
tw
is
the
HC1­
equivalent
emission
rate,
lb/
hr
ER
i
is
the
emission
rate
of
HAP
i
in
lbs/
hr
RfC
i
is
the
reference
concentration
of
HAP
i
RfC
HCl
is
the
reference
concentration
of
HCl
(
3)
You
must
use
the
RfC
values
for
hydrogen
chloride
and
chlorine
gas
found
at
http://
epa.
gov/
ttn/
atw/
toxsource/
sumnmary.
html.
(
4)
The
hydrogen
chloride
and
chlorine
gas
emission
rates
you
use
to
calculate
the
HClequivalent
emission
rate
limit
for
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns
must
not
result
in
total
chlorine
emission
concentrations
exceeding
the
standards
provided
by
§
§
63.1203,
63.1204,
and
63.1205.
(
c)
Eligibility
demonstration.
(
1)
General.
You
must
perform
an
eligibility
demonstration
to
determine
whether
your
selected
hydrogen
chloride
and
chlorine
gas
emission
rates
meet
the
national
exposure
standards
using
either
a
look­
up
table
analysis
prescribed
by
paragraph
(
c)(
3)
of
this
section,
or
a
site­
specific
compliance
demonstration
prescribed
by
paragraph
(
c)(
4)
of
this
section.
40
(
2)
Definition
of
eligibility.
Your
facility
is
eligible
for
the
alternative
risk­
based
standards
for
total
chlorine
if
either:
(
i)
The
sum
of
the
calculated
HCl­
equivalent
emission
rates
for
all
on­
site
hazardous
waste
combustors
is
below
the
appropriate
value
in
the
look­
up
table;
or
(
ii)
Your
site­
specific
compliance
demonstration
indicates
that
your
maximum
Hazard
Index
for
hydrogen
chloride
and
chlorine
gas
emissions
from
all
on­
site
hazardous
waste
combustors
at
a
location
where
people
live
is
less
than
or
equal
to
1.0,
rounded
to
the
nearest
tenths
decimal
place
(
0.1).
(
3)
Look­
up
table
analysis.
(
i)
The
look­
up
table
is
provided
as
Table
XX1
to
Subpart
EEEthis
section.
(
ii)
To
determine
the
correct
HCl­
equivalent
emission
rate
value
from
the
look­
up
table,
you
must
use
the
average
stack
height
for
your
hazardous
waste
combustors
(
i.
e.,
the
mean
of
the
stack
height
of
all
on­
site
hazardous
waste
combustors)
and
the
minimum
distance
between
any
hazardous
waste
combustor
stack
and
the
property
boundary.
(
iii)
If
one
or
both
of
these
values
for
stack
height
and
distance
to
nearest
property
boundary
do
not
match
the
exact
values
in
the
look­
up
table,
you
would
use
the
next
lowest
table
value.
(
iv)
You
are
not
eligible
for
the
look­
up
table
analysis
if
your
facility
is
located
in
complex
terrain.
(
v)
If
the
sum
of
the
calculated
HCl­
equivalent
emission
rates
for
all
on­
site
hazardous
waste
combustors
is
below
the
appropriate
value
in
the
look­
up
table,
the
emission
limit
for
total
chlorine
for
each
combustor
is
the
HCl­
equivalent
emission
rate
you
calculated.
(
4)
Site­
specific
compliance
demonstration.
(
i)
You
may
use
any
scientifically­
accepted
peer­
reviewed
risk
assessment
methodology
for
your
site­
specific
compliance
demonstration.
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
Website
at
www.
epa.
gov/
ttn/
atw.
(
ii)
Your
facility
is
eligible
for
the
alternative
risk­
based
total
chlorine
emission
limit
if
your
site­
specific
compliance
demonstration
shows
that
the
maximum
Hazard
Index
for
hydrogen
chloride
and
chlorine
gas
emissions
from
each
on­
site
hazardous
waste
combustor
is
less
than
or
equal
to
1.0
rounded
to
the
nearest
tenths
decimal
place
(
0.1).
(
iii)
At
a
minimum,
your
site­
specific
compliance
demonstration
must:
(
A)
Estimate
long­
term
inhalation
exposures
through
the
estimation
of
annual
or
multiyear
average
ambient
concentrations;
(
B)
Estimate
the
inhalation
exposure
for
the
actual
individual
most
exposed
to
the
facility's
emissions
from
hazardous
waste
combustors;
(
C)
Use
site­
specific,
quality­
assured
data
wherever
possible;
(
D)
Use
health­
protective
default
assumptions
wherever
site­
specific
data
are
not
available,
and:
(
E)
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
41
measurement
expert.
(
iv)
Your
site­
specific
compliance
demonstration
need
not:
(
A)
Assume
any
attenuation
of
exposure
concentrations
due
to
the
penetration
of
outdoor
pollutants
into
indoor
exposure
areas;
(
B)
Assume
any
reaction
or
deposition
of
the
emitted
pollutants
during
transport
form
the
emission
point
to
the
point
of
exposure.
(
v)
If
your
site­
specific
compliance
demonstration
documents
that
the
maximum
Hazard
Index
for
hydrogen
chloride
and
chlorine
gas
emissions
from
your
hazardous
waste
combustors
is
less
than
or
equal
to
1.0,
you
would
establish
a
maximum
HCl­
equivalent
emission
rate
limit
for
each
combustor
based
on
the
hydrogen
chloride
and
chlorine
gas
emission
rates
used
in
this
sitespecific
compliance
demonstration.
(
d)
Review
and
approval
of
eligibility
demonstrations.
(
1)
Content
of
the
eligibility
demonstration.
(
i)
General.
The
eligibility
demonstration
must
include
the
following
information,
at
a
minimum:
(
A)
Identification
of
each
hazardous
waste
combustor
combustion
gas
emission
point
(
e.
g.,
generally,
the
flue
gas
stack);
(
B)
The
maximum
capacity
at
which
each
combustor
will
operate,
and
the
maximum
rated
capacity
for
each
combustor,
using
the
metric
of
stack
gas
volume
emitted
per
unit
of
time,
as
well
as
any
other
metric
that
is
appropriate
for
the
combustor
(
e.
g.,
million
Btu/
hr
heat
input
for
boilers;
tons
of
dry
raw
material
feed/
hour
for
cement
kilns);
(
C)
Stack
parameters
for
each
combustor,
including,
but
not
limited
to
stack
height,
stack
area,
stack
gas
temperature,
and
stack
gas
exit
velocity;
(
D)
Plot
plan
showing
all
stack
emission
points,
nearby
residences,
and
property
boundary
line;
(
E)
Identification
of
any
stack
gas
control
devices
used
to
reduce
emissions
from
each
combustor;
(
F)
Identification
of
the
RfC
values
used
to
calculate
the
HCl­
equivalent
emissions
rate;
(
G)
Calculations
used
to
determine
the
HCl­
equivalent
emission
rate;
(
H)
For
incinerators,
cement
kilns,
and
lightweight
aggregate
kilns,
calculations
used
to
determine
that
the
HCl­
equivalent
emission
rate
limit
for
each
combustor
does
not
exceed
the
standards
for
total
chlorine
at
§
§
63.1203,
63.1204,
and
63.1205;
and
(
I)
The
HCl­
equivalent
emission
rate
limit
for
each
hazardous
waste
combustor
that
you
will
certify
in
the
Documentation
of
Compliance
required
under
§
63.1211(
d)
that
you
will
not
exceed,
and
the
limits
on
the
operating
parameters
specified
under
§
63.1209(
o)
that
you
will
establish
in
the
Documentation
of
Compliance.
(
ii)
Additional
content
of
look­
up
table
demonstration.
If
you
use
the
look­
up
table
analysis,
your
eligibility
demonstration
must
also
contain,
at
a
minimum,
the
following:
(
A)
Calculations
used
to
determine
the
average
stack
height
of
on­
site
hazardous
waste
combustors;
(
B)
Identification
of
the
combustor
stack
with
the
minimum
distance
to
the
property
boundary
of
the
facility;
and
(
C)
Comparison
of
the
values
in
the
look­
up
table
to
your
maximum
HCl­
equivalent
42
emission
rate.
(
iii)
Additional
content
of
a
site­
specific
compliance
demonstration.
If
you
use
a
sitespecific
compliance
demonstration,
your
eligibility
demonstration
must
also
contain,
at
a
minimum,
the
following:
(
A)
Identification
of
the
risk
assessment
methodology
used;
(
B)
Documentation
of
the
fate
and
transport
model
used;
(
C)
Documentation
of
the
fate
and
transport
model
inputs,
including
the
stack
parameters
listed
in
paragraph
(
d)(
1)(
i)(
C)
of
this
section
converted
to
the
dimensions
required
for
the
model;
(
D)
As
applicable:
(
1)
Meteorological
data;
(
2)
Building,
land
use,
and
terrain
data;
(
3)
Receptor
locations
and
population
data;
and
(
4)
Other
facility­
specific
parameters
input
into
the
model;
(
E)
Documentation
of
the
fate
and
transport
model
outputs;
(
F)
Documentation
of
any
exposure
assessment
and
risk
characterization
calculations;
and
(
G)
Documentation
of
the
predicted
Hazard
Index
forHCl­
equivalents
and
comparison
to
the
limit
of
less
than
1.0.
(
2)
Review
and
approval.
(
i)
Existing
sources.
(
A)
If
you
operate
an
existing
source,
you
must
be
in
compliance
with
the
emission
standards
on
the
compliance
date.
If
you
elect
to
comply
with
the
alternative
risk­
based
emission
rate
limit
for
total
chlorine,
you
must
have
completed
the
eligibility
demonstration
and
received
approval
from
your
delegated
permitting
authority
by
the
compliance
date.
(
B)
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
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.
(
C)
Your
permitting
authority
will
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.
(
D)
If
your
permitting
authority
has
not
approved
your
eligibility
demonstration
to
comply
with
a
risk­
based
HCl­
equivalent
emission
rate(
s)
by
the
compliance
date,
you
must
comply
with
the
MACT
emission
standards
for
total
chlorine
gas
under
§
§
63.1203A,
63.1204(
A),
63.1205A,
63.1216,
and
63.1217
of
this
chapter.
(
ii)
New
sources.
General.
(
A)
If
you
operate
a
source
that
is
not
an
existing
source
and
that
becomes
subject
to
Subpart
EEE,
you
must
comply
with
the
MACT
emission
standards
for
total
chlorine
unless
and
until
your
eligibility
demonstration
has
been
approved
by
the
permitting
authority.
(
B)
If
you
operate
a
new
or
reconstructed
source
that
starts
up
before
the
effective
date
of
43
the
emission
standards
proposed
today,
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
the
effective
date
of
§
§
63.1216
and
63.1217,
you
would
be
required
to
comply
with
the
emission
standards
under
§
§
63.1216
and
63.1217
until
your
eligibility
demonstration
is
approved
by
your
permitting
authority.
(
C)
If
you
operate
a
new
or
reconstructed
source
that
starts
up
after
the
effective
date
of
the
emission
standards
proposed
today,
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
after
the
effective
date
of
§
§
63.1216
and
63.1217,
you
would
be
required
to
comply
with
the
emission
standards
under
§
§
63.1216
and
63.1217
until
your
eligibility
demonstration
is
approved
by
your
permitting
authority.
(
e)
Testing
and
monitoring
requirements.
(
1)
General.
You
must
document
compliance
during
the
comprehensive
performance
test
under
§
63.1207
with
the
HCl­
equivalent
emission
rate
limit
established
in
an
approved
eligibility
demonstration
for
each
hazardous
waste
combustor.
(
2)
Test
methods.
(
i)
If
you
operate
a
cement
kiln
or
a
combustor
equipped
with
a
dry
acid
gas
scrubber,
you
must
should
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
gas.
(
ii)
If
you
operate
an
incinerator,
boiler,
or
lightweight
aggregate
kiln,
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
total
chlorine,
and
calculate
chlorine
gas
by
difference
if:
(
A)
The
bromine/
chlorine
ratio
in
feedstreams
is
greater
than
5
percent;
or
(
B)
The
sulfur/
chlorine
ratio
in
feedstreams
is
greater
than
50
percent.
(
3)
Operating
parameter
limits.
(
i)
You
must
establish
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
specified
under
paragraph
(
e)(
3)(
ii)
of
this
section.
(
ii)
Annual
rolling
average
feedrate.
You
must
establish
an
annual
rolling
average
feedrate
limit
for
total
chlorine
and
chloride
as
the
average
of
the
test
run
averages
during
the
comprehensive
performance
test.
(
A)
To
document
compliance
with
the
feedrate
limit,
you
must
know
the
total
chlorine
and
chloride
concentration
of
feedstreams
at
all
times
and
continuously
monitor
the
flowrate
of
all
feedstreams.
(
B)
You
must
measure
the
flowrate
of
each
feedstream
at
least
once
each
minute
and
update
the
annual
rolling
average
hourly
based
on
the
average
of
the
60
previous
1­
minute
measurements.
(
f)
Changes.
(
1)
Changes
over
which
you
have
control.
(
i)
Changes
in
design,
operation,
or
maintenance
of
a
hazardous
waste
combustor
that
may
affect
the
rate
of
emissions
of
HClequivalents
from
the
combustor
are
subject
to
the
requirements
of
§
63.1206(
b)(
5).
(
ii)
If
you
change
the
information
documented
in
the
demonstration
of
eligibility
for
the
44
HCl­
equivalent
emission
rate
limit
and
which
is
used
to
establish
the
HCl­
equivalent
emission
rate
limit,
you
are
subject
to
the
following
requirements:
(
A)
Changes
that
would
decrease
the
allowable
HCl­
equivalent
emission
rate
limit.
If
you
plan
to
make
a
change
that
would
decrease
the
allowable
HCl­
equivalent
emission
rate
limit
documented
in
your
eligibility
demonstration,
you
must
comply
with
§
63.1206(
b)(
5)(
i)(
A­
C);
(
B)
Changes
that
would
not
decrease
the
allowable
HCl­
equivalent
emission
rate
limit.
(
1)
If
you
determine
that
a
change
would
not
decrease
the
allowable
HCl­
equivalent
emission
rate
limit
documented
in
your
eligibility
demonstration,
you
must
document
the
change
in
the
operating
record
upon
making
such
change.
(
2)
If
the
change
would
increase
your
allowable
HCl­
equivalent
emission
rate
limit
and
you
elect
to
establish
a
higher
HCl­
equivalent
limit,
you
must
submit
a
revised
eligibility
demonstration
for
review
and
approval.
Upon
approval
of
the
revised
eligibility
demonstration,
you
must
comply
with
§
63.1206(
b)(
5)(
i)(
A)(
2),
(
B),
and
(
C).
(
2)
Changes
over
which
you
do
not
have
control.
(
i)
You
must
review
the
documentation
you
use
in
your
eligibility
demonstration
every
five
years
on
the
anniversary
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
allowable
HCl­
equivalent
emission
rate
limit,
or
a
revised
eligibility
demonstration
for
a
revised
HCl­
equivalent
emission
rate
limit
TABLE
XX
to
Subpart
EEE.
(
ii)
If
you
determine
that
you
cannot
demonstrate
compliance
with
a
lower
allowable
HClequivalent
emission
rate
limit
during
the
comprehensive
performance
test
because
you
cannot
complete
changes
to
the
design
or
operation
of
the
source
prior
to
the
test,
you
may
request
that
the
permitting
authority
grant
you
additional
time
as
necessary
to
make
those
changes,
not
to
exceed
three
years.

TABLE
1
to
Section
63.1215.
Allowable
toxicity­
weighted
emission
rate
expressed
in
HCl
equivalents
(
lb/
hr)

Stack
Ht
(
m)
Distance
to
Property
Boundary
(
m)
10
30
50
100
200
500
2
0.0244
0.0322
0.0338
0.0627
0.173
0.766
5
0.0475
0.0612
0.0881
0.168
0.309
0.881
10
0.165
0.187
0.216
0.336
0.637
1.59
20
0.661
1.01
1.01
1.2
1.87
4.31
35
2.02
2.02
4.04
4.11
5.08
10.4
50
4.11
4.11
4.11
9.74
10.8
18.0
