1
"
Hunt,
Tim"
<
Tim_
Hunt@
afandpa
To:
Dave
Guinnup/
RTP/
USEPA/
US@
EPA
.
org>
cc:
Mary
Kissell/
RTP/
USEPA/
US@
EPA
Subject:
Plywood
MACT
09/
17/
2003
06:
01
PM
Dave,

Following
up
to
our
conversation
on
Monday,
here
is
a
paper
that
discusses
why
an
HI
of
one
or
more
makes
sense
for
acrolein
in
the
context
of
Plywood
MACT.
It
also
points
out
that
the
RfC
for
acrolein
should
be
3
times
higher
as
well
based
on
the
best
science.
I
think
the
paper
is
self
explanatory
but
I
would
be
glad
to
answer
any
questions.

Hope
you
(
and
me)
weather
the
Hurricane
tomorrow
and
Friday.

PS.
I
confirmed
with
ENSR
that
once
formaldehyde
CIIT
is
used
that
acrolein
becomes
the
risk
driver
even
if
acetaldehyde
if
unchanged
since
only
2
or
3
facilities
have
risks
greater
than
1x10­
6
but
HI
<
1.

<<
Acrolein
HI­
RfC
Paper
9­
16­
03.
doc>>

Timothy
Hunt
Senior
Director,
Air
Quality
Programs
American
Forest
and
Paper
Association
Suite
800
1111
19th
St.,
NW
Washington,
DC
20036
phone:
202­
463­
2588
fax:
202­
463­
2423
Tim_
Hunt@
afandpa.
org
(
See
attached
file:
Acrolein
HI­
RfC
Paper
9­
16­
03.
doc)
2
The
Case
of
Acrolein
Demonstrates
Why
an
HI
of
1.0
Is
Amply
Protective
The
case
of
acrolein
further
demonstrates
why
an
HI
of
1.0
(
or
greater)
will
be
amply
protective
of
human
health.
On
February
25,
2002,
EPA
provided
for
public
information
a
draft
Toxicological
Review
and
draft
IRIS
Summary
for
acrolein.
The
draft
IRIS
document
identifies
a
proposed
RfC
of
0.03
µ
g/
m3
based
on
a
subchronic
study
by
Feron
et
al.
(
1978)
on
golden
hamsters,
rats
and
rabbits.
1
In
that
study,
minimal
histopathological
changes
were
found
in
the
nasal
cavity
of
one
male
rat
exposed
to
0.4
ppm,
but
none
were
reported
in
other
species
at
this
concentration.
0.4
ppm
(
0.9
mg/
m3)
was
considered
to
be
a
minimal
LOAEL
for
nasal
lesions.
The
LOAEL
of
0.9
mg/
m3
was
adjusted
to
continuous
exposure,
resulting
in
a
LOAEL
(
adj)
of
0.16
mg/
m3.
This
value
was
further
adjusted
to
a
Human
Equivalent
Concentration
(
HEC)
of
0.03
mg/
m3.
The
LOAEL
(
HEC)
was
divided
by
a
total
uncertainty
factor
of
1000,
resulting
in
an
RfC
of
0.00003
mg/
m3
(
0.03
µ
g/
m3).
The
uncertainty
factor
consists
of
factors
of
3
for
use
of
a
LOAEL,
3
for
interspecies
variability,
10
for
intraspecies
variability
in
sensitivity,
and
10
for
extrapolation
from
a
subchronic
to
a
chronic
exposure
duration.

EPA's
interpretation
of
this
study
is
exceptionally
conservative.
As
California's
Office
of
Environmental
Health
Hazard
Assessment
(
OEHHA)
correctly
notes,
a
single
rat
showing
slight
inflammatory
changes
is
insufficient
to
demonstrate
a
statistically
significant
increase
in
effects
at
the
0.4
ppm
dose
level.
2
In
light
of
this
minimal
change
in
a
single
animal
 
which
typically
would
be
insufficient
to
be
considered
a
dose­
related
effect
 
EPA's
adoption
of
a
thousand­
fold
uncertainty
factor
seems
excessive.

Indeed,
California's
OEHHA
developed
a
noncancer
reference
exposure
level
(
REL)
of
0.06
µ
g/
m3
based
on
the
same
study
used
by
EPA.
3
The
difference
between
the
two
values
are
that
OEHHA
uses
a
lower
uncertainty
factor
of
3
to
account
for
the
subchronic
study
(
compared
to
U.
S.
EPA's
uncertainty
factor
of
10).
OEHHA's
documentation
states
that
based
on
OEHHA's
methodology
for
chronic
RELs,
62
days
is
8.5%
of
2
years
and
is
above
the
minimum
length
that
would
justify
use
of
a
subchronic
uncertainty
factor
of
3,
rather
than
10.
The
uncertainty
factors
used
by
OEHHA
are
(
1)
3
to
account
for
use
of
a
LOAEL,
(
2)
3
to
account
for
use
of
a
subchronic
study,
(
3)
3
to
account
for
interspecies
uncertainty,
and
(
4)
10
to
account
for
intraspecies
uncertainty.
The
cumulative
uncertainty
factor
is
300.
Thus,
the
value
is
only
slightly
less
conservative
than
the
draft
RfC
developed
by
EPA
 
but
appears
more
appropriate
in
light
of
the
minimal
effect,
seen
in
a
single
animal,
that
is
the
basis
for
the
health
benchmark.

Even
OEHHA's
health
benchmark
is
far
more
conservative
than
the
Health
Canada
Tolerable
Concentration
(
TC)
of
0.4
µ
g/
m3.
Significantly,
Health
Canada
defines
a
Tolerable
Concentration
as
"
airborne
concentrations
to
which
it
is
believed
that
a
person
can
be
exposed
1
The
prior
IRIS
assessment
included
an
even
lower
RfC,
0.02
ug/
m3.

2
OEHHA,
Chronic
Toxicity
Summary
for
Acrolein,
p.
A­
5
(
December
2000),
available
at
http://
www.
oehha.
org/
air/
chronic_
rels/
pdf/
107028.
pdf.

3
Like
an
RfC,
an
REL
is
intended
to
represent
the
airborne
concentration
of
a
substance
to
which
the
general
population,
including
susceptible
individuals,
may
be
exposed
continuously
for
a
lifetime
without
significant
adverse
effects.
3
continuously
over
a
lifetime
without
deleterious
effect."
4
In
other
words,
a
TC
is
intended
to
be
as
health­
protective
as
an
RfC
or
REL.
The
Health
Canada
TC
differs
from
EPA's
RfC
and
California's
REL
primarily
because
Health
Canada
declined
to
adopt
an
uncertainty
factor
(
either
3
or
10)
to
extrapolate
from
a
subchronic
to
a
chronic
study,
such
that
Health
Canada
used
a
total
uncertainty
factor
of
100,
rather
than
1000.
The
basis
for
Health
Canada's
decision
is
that
there
is
no
evidence
that
the
severity
of
the
critical
effect
increases
with
duration
of
exposure,
rendering
unnecessary
an
additional
uncertainty
factor.
5
These
comparisons
with
other
health
benchmarks
for
acrolein
demonstrate
that
EPA
has
taken
the
most
conservative
approach
to
evaluating
the
acrolein
toxicological
database,
using
the
maximum
uncertainty
factors
that
could
be
justified
and
thereby
developing
an
RfC
that
almost
certainly
goes
beyond
what
is
needed
to
protect
human
health.
Adopting
an
HI
of
0.2
 
on
top
of
this
health
benchmark
 
would
add
another
five­
fold
safety
factor
to
this
already
extremely
conservative
RfC.
In
other
words,
an
effective
5000­
fold
uncertainty
factor
would
be
adopted
to
protect
against
minimal
effects
seen
in
a
single
animal.
To
further
compound
the
conservatism
of
the
acrolein
health
benchmark
in
this
way
would
 
in
the
words
of
the
Presidential
/
Congressional
Commission
on
Risk
Assessment
and
Risk
Management
 
render
any
assessments
"
so
unrealistic
[
as
to]
impair.
.
.
the
scientific
credibility
of
health
risk
assessment."
6
The
conservatism
of
the
acrolein
health
benchmark
is
particularly
significant
for
wood
product
facilities,
as
the
available
data
suggest
that
acrolein
is
the
HAP
of
greatest
importance
in
determining
the
risk
from
these
facilities.
AF&
PA
commissioned
ENSR
to
conduct
a
risk
assessment
of
wood
products
facilities.
In
a
subsequent
sensitivity
analysis
of
that
assessment,
7
ENSR
determined
that
acrolein
is
responsible
for
between
81.0
and
99.9
of
the
noncancer
risks
from
wood
products
facilities
(
with
the
variation
depending
on
assumptions
about
emissions,
health
benchmarks
and
the
number
of
pollutants
evaluated).

In
other
words,
the
acrolein
health
benchmark
 
and
as
a
result,
the
assumptions
surrounding
that
health
benchmark
 
will
almost
entirely
determine
the
hazard
index
for
wood
product
facilities.
That
means,
in
turn,
that
there
is
at
least
a
thousand­
fold
safety
factor
between
a
wood
products
property
line
concentration
that
corresponds
to
an
HI
of
1.0
and
the
dose
level
at
which
a
single
animal
experienced
minimal
health
effects.
And,
again
assuming
an
HI
of
1.0,
that
safety
factor
is
two
to
three
times
more
conservative
than
what
California
deemed
sufficient
to
protect
sensitive
individuals
from
any
adverse
effect
following
a
lifetime
of
exposure,
and
ten
times
more
conservative
that
what
Health
Canada
deemed
to
be
similarly
protective.
Under
these
circumstances,
it
surely
is
regulatory
overkill
to
compound
the
already
extremely
conservative
regulatory
benchmark
by
applying
an
HI
of
less
than
1.0.

4
Health
Canada,
Health
Based
Tolerable
Daily
Intakes/
Concentrations
and
Tumorigenic
Doses/
Concentrations
for
Priority
Substances,
p.
4
(
1996).

5
See
http://
www.
tera.
org/
iter.

6
Risk
Assessment
and
Risk
Management
In
Regulatory
Decision­
Making,
1997,
Vol.
2
at
74.

7
See
"
ENSR/
AF&
PA
Sensitivity
Analysis
of
EPA's
Risk
Assessment
for
Plywood
and
Composite
Panel
Facilities,"
March
2003.
4
Not
only
is
an
HI
of
less
than
1.0
not
necessary
to
protect
human
health,
in
the
case
of
wood
products
facilities,
doing
so
would
result
in
significant
corollary
adverse
environmental
impacts
(
see
Table
on
page
4).
Industry
has
estimated
that
if
the
HI
is
lowered
to
0.2
from
1.0,
an
additional
56
wood
products
facilities
would
fail
to
meet
the
risk
cut­
offs
and
thus
would
be
required
to
install
the
MACT
technology
(
regenerative
thermal
oxidizers
or
RTOs
most
likely).
Doing
so
would
reduce
acrolein
emissions
by
approximately
9
tons,
or
330
pounds
per
facility.
These
acrolein
emissions
represent
only
0.03%
of
the
total
inventory
according
to
the
1996
NTI.

Powering
the
RTOs,
however,
would
cause
those
facilities
to
use
an
additional
7
billion
cubic
feet
of
natural
gas
and
15
trillion
Btus
of
electricity
 
equivalent
to
the
power
used
by
150,000
households
over
the
course
of
a
year.
The
RTOs
would
generate
990,000
short
tons
of
carbon
dioxide,
2,800
tons
of
nitrogen
oxides
and
11,000
tons
of
sulfur
dioxide
 
all
at
a
capital
cost
of
about
$
180
million,
plus
operating
and
energy
expenses
which
can
exceed
$
1
million
per
year
per
facility.
8
These
environmental
disbenefits
would
be
incurred
to
provide
a
five­
thousand
fold
safety
factor
between
worst­
case
potential
human
exposures
and
the
dose
level
at
which
a
single
animal
experienced
minimal
health
effects.
In
the
case
of
acrolein,
it
is
abundantly
clear
that
the
environmental
harm
associated
with
the
more
stringent
hazard
index
more
than
outweighs
any
potential
human
health
benefits
that
might
be
gained.

Indeed,
given
the
wood
products
industry's
minuscule
contribution
to
nationwide
acrolein
emissions,
coupled
with
the
environmental
disbenefits
of
the
MACT
technology,
it
would
be
appropriate
not
to
adopt
EPA's
excessively
conservative
RfC.
Rather,
EPA
should
adopt
the
slightly
less
conservative
(
but
still
highly
conservative)
chronic
REL
developed
by
California
 
a
value
that
is
300­
fold
below
the
dose
at
which
a
single
animal
experienced
minimal
nasal
lesions,
and
that
is
still
almost
an
order
of
magnitude
lower
than
what
Health
Canada
has
deemed
protective
for
lifetime
exposures.
Doing
so
would
further
reduce
the
environmental
disbenefits
associated
with
RTOs,
while
still
ensuring
protection
of
human
health
with
an
ample
margin
of
safety.

8
AF&
PA
provided
extensive
risk
and
economic
comments
and
analyses
to
EPA
on
the
proposed
PCWP
MACT.
The
impacts
of
an
alternative
hazard
index
draws
from
reports
and
assessment
prepared
by
ENSR
while
the
disbenefit
information
is
based
on
a
life
cycle
inventory
study
done
by
Franklin
Associates
and
subsequently
published
in
the
Forest
Products
Journal
(
March
2002,
Vol.
52,
No.
3,
pp.
50­
59).
The
Effect
of
Alternative
Hazard
Indices
for
Acrolein9
on
Risk
Screening
for
Facilities
covered
by
the
Plywood
and
Composite
Wood
Panel
MACT
Hazard
Index
Level
Range
Number
of
Facilities
Covered
in
the
Hazard
Index
Range10
(
%
of
facilities)
Acrolein
Emissions
(
tons/
yr.)
that
would
be
Controlled
if
MACT
were
applied
to
Facilities
in
HI
Range
(%
of
total
PCWP
MACT/

&
nationwide
emissions
)
11
Natural
gas
and
Electricity
Usage
for
RTOs/
Incinerators
if
MACT
were
applied
to
Facilities
in
HI
Range12
[
Equivalency
to
Household
Electricity
Use]
Increases
in
CO2
Emissions
from
MACT
controls4
(
CO2
short
tons)
Increases
in
NOx
and
SO2
Emissions
from
MACT
controls4
(
Tons)
Capital
Cost
for
Facilities
in
the
HI
Range4
($
M)

HI
<
0.2
55
facilities
(
30
%)
3.3
tons/
yr.
:
average
of
119
lbs./
facility
(
1.0%/
0.01%)
Natural
gas
 
6.6
billion
ft3
Electricity
 
14.9
trillion
Btus
[
150,000
households]
970,000
NOx
 
2,800
SO2
 
11,000
$
180
M
0.2
<
HI
<
1.0
56
facilities
(
30
%)
9.2
tons/
yr.:
average
of
330
lbs./
facility
(
3.0%/
0.03
%)
Natural
gas
 
6.7
billion
ft3
Electricity
 
15.2
trillion
Btus
[
150,000
households]
990,000
NOx
 
2,800
SO2
 
11,000
$
180
M
1.0
<
HI
<
3.013
40
facilities
(
22
%)
25.2
tons/
yr.:
average
of
1,260
lbs./
facility
(
8.0
%/
0.09%)
Natural
gas
 
4.8
billion
ft3
Electricity
 
10.9
trillion
Btus
[
110,000
households]
700,000
NOx
 
2,050
SO2
 
7,900
$
110
M
HI
>
3.0
33
facilities
(
18
%)
215
tons/
yr.:
average
of
13,050
lbs./
facility
(
69
%/
0.7%)
Natural
gas
 
3.9
billion
ft3
Electricity
 
9
trillion
Btus
[
90,000
households]
580,000
NOx
 
1,675
SO2
 
6,500
$
130
M
Total
184
facilities
253
tons
reduced
of
313
tons
emitted
(
81%/
0.9%)
Natural
gas
 
22
billion
ft3
Electricity
 
50
trillion
Btus
[
500,000
households]
3,200,000
NOx
 
9,300
SO2
 
36,000
$
600
M
9
Risk
driver
for
non
cancer
affects
at
wood
product
facilities
is
acrolein
according
to
EPA
and
ENSR
analyses;
assumes
acrolein
RfC
is
0.02
µ
g/
m3
(
IRIS).

10
Number
of
facilities
affected
based
on
ENSR
sensitivity
analysis
case
11.

11
MACT
applied
to
all
PCWP
facilities
would
control
about
81%
of
total
acrolein
emissions
(
313
tons);
national
percentages
based
on
EPA
NATA
1996
estimates
which
show
major
sources
contribute
about
one
percent
of
total
emissions;
area
sources
(
57%)
and
non­
road
(
25%)
are
the
largest
emitters.

12
Estimates
for
increases
in
energy,
CO2,
NOx
and
SO2
emissions,
and
cost
are
assumed
to
be
proportional
to
number
of
facilities
in
the
HI
range.

13
Hazard
Index
of
3.0
is
equivalent
to
a
HI
of
1.0
using
an
RfC
of
0.06
ug/
m3
(
CA
value).
