­­­­­
Original
Message­­­­­
From:
Kissell.
Mary@
epamail.
epa.
gov
[
mailto:
Kissell.
Mary@
epamail.
epa.
gov]
Sent:
Wednesday,
September
08,
2004
11:
12
AM
To:
King,
Neil
Subject:
RE:
EPA's
Rationale
Regarding
Ni
Emissions
in
PCWP
MACT
The
PCWP
MACT
is
independent
of
any
decisions
concerning
NATA.
I
do
not
know
the
status
of
the
consideration
of
your
comments
for
the
1999
NATA.

"
King,
Neil"
<
Neil.
King@
wilmerhale
To:
Mary
Kissell/
RTP/
USEPA/
US@
EPA
.
com>
cc:
Subject:
RE:
EPA's
Rationale
Regarding
Ni
09/
08/
2004
10:
34
AM
Emissions
in
PCWP
MACT
Dear
Ms.
Kissell:

Thanks
very
much
for
the
prompt
response.
I
suspected
the
65%
nickel
subsulfide
assumption
was
based
on
the
1996
NATA
rationale,
but
I
wanted
to
confirm
the
point.

Although
it
probably
is
too
late
to
do
anything
about
it
now
as
far
as
the
Plywood
and
Composite
Wood
Product
MACT
is
concerned,
I
do
want
to
let
you
know
that
the
nickel­
producing
industry
believes
the
65%
subsulfide
speciation
assumption
reflected
in
the1996
NATA
is
completely
unfounded.
In
August
2002,
we
submitted
Comments
on
the
draft
1996
NATA,
explaining
why
the
65%
assumption
overstated
the
nickel
subsulfide
portion
of
total
nickel
emissions
by
an
order
of
magnitude
or
more,
and
we
asked
that
an
appropriate
correction
be
made
in
the
1999
NATA.
We
are
hopeful
that
such
a
correction
will
be
made,
and
we
trust
that
the
approach
reflected
in
the
PCWP
MACT
does
not
imply
that
our
request
has
been
rejected.
For
your
information,
I
am
attaching
a
copy
of
those
Comments,
along
with
the
accompanying
cover
letter.

Incidentally,
although
it
is
not
used
in
the
methodology
for
making
a
low­
risk
demonstration,
the
preamble
to
the
PCWP
MACT
Rule
states
that
nickel
carbonyl
might
be
emitted
from
PCWP
facilities.
69
Fed.
Reg.
at
45948.
Although
we
have
little
familiarity
with
such
facilities,
we
would
be
very
surprised
to
find
nickel
carbonyl
emissions
from
any
of
the
processes
(
including
directfired
process
units)
at
PCWP
facilities.

Neil
J.
King
Wilmer
Cutler
Pickering
Hale
and
Dorr
LLP
2445
M
Street
NW
Washington,
DC
20037
USA
+
1
202
663
6061
+
1
202
772
6061
fax
neil.
king@
wilmerhale.
com
_____

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LLP
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Thank
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_____

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­­­­­
Original
Message­­­­­
From:
Kissell.
Mary@
epamail.
epa.
gov
[
mailto:
Kissell.
Mary@
epamail.
epa.
gov]
Sent:
Wednesday,
September
08,
2004
9:
46
AM
To:
King,
Neil
Subject:
EPA's
Rationale
Regarding
Ni
Emissions
in
PCWP
MACT
Mr.
King,

It
seemed
easier
to
email
you
than
to
telephone.

For
the
Plywood
and
Composite
Wood
Product
MACT,
EPA
assumed
that
65%
of
nickel
emissions
are
subsulfide
based
on
the
1996
NATA
rationale.
The
NATA
rationale
follows
and
the
web
link
is
­­
http://
www.
epa.
gov/
ttn/
atw/
nata/
nettables.
pdf
Facilities
are
also
free
to
measure
nickel
emissions
to
achieve
a
more
accurate
speciation
profile.

NATA
Rationale:

Nickel.
The
IRIS
URE
for
nickel
inhalation
shown
in
Table
1
below
was
derived
from
evidence
of
the
carcinogenic
effects
of
insoluble
nickel
compounds
in
crystalline
form.
Soluble
nickel
species,
and
insoluble
species
in
amorphous
form,
do
not
appear
to
produce
genotoxic
effects
by
the
same
mode
of
action
as
insoluble
crystalline
nickel.
Nickel
speciation
information
for
some
of
the
largest
nickel­
emitting
sources
(
including
oil
combustion,
coal
combustion,
and
others)
suggests
that
at
least
35%
of
total
nickel
emissions
may
be
soluble
compounds.
The
remaining
insoluble
nickel
emissions
are
not
wellcharacterized
however.
Consistent
with
this
limited
information,
this
analysis
has
conservatively
assumed
that
65%
of
emitted
nickel
is
insoluble,
and
that
all
insoluble
nickel
is
crystalline.
On
this
basis,
the
nickel
URE
(
based
on
nickel
subsulfide,
and
representative
of
pure
insoluble
crystalline
nickel)
was
adjusted
to
reflect
an
assumption
that
65%
of
the
total
mass
of
nickel
may
be
carcinogenic.
The
ATSDR
MRL
in
Table
2
was
not
adjusted,
however,
because
the
noncancer
effects
of
nickel
are
not
thought
to
be
limited
to
the
crystalline,
insoluble
form.

(
See
attached
file:
Cover
letter
for
NATA
Comments.
doc)(
See
attached
file:
NATA
Response
3.
doc)
August
20,
2002
Mr.
David
Guinnup
U.
S.
Environmental
Protection
Agency
Mail
Code
C404­
01
Research
Triangle
Park,
NC
27711
Re:
National­
Scale
Air
Toxics
Assessment
Dear
Mr.
Guinnup:

On
behalf
of
the
Nickel
Producers
Environmental
Research
Association
(
NiPERA),
the
Nickel
Development
Institute
(
NiDI),
and
Inco
United
States,
Inc.,
I
am
enclosing
Comments
regarding
the
Unit
Risk
Estimate
("
URE")
that
was
used
in
the
National­
Scale
Air
Toxics
Assessment
for
1996
("
NATA­
1996")
to
characterize
estimated
cancer
risks
associated
with
exposures
to
nickel
compounds
in
the
ambient
air.

As
you
will
see,
NiDI,
NiPERA,
and
Inco
believe
that
the
URE
used
in
NATA­
1996
was
inappropriate
and
produced
an
exaggerated
estimate
of
the
number
of
people
living
in
census
tracts
where
exposures
to
nickel
compounds
are
estimated
to
pose
a
lifetime
cancer
risk
exceeding
10­
6
(
one
in
one
million).
Although
we
do
not
have
the
data
inputs
for
EPA's
exposure
model,
we
expect
that
use
of
a
corrected
and
more
appropriate
URE
would
result
in
a
downgrading
of
nickel
compounds
from
the
category
of
"
Important
National
Cancer
Risk
Contributor"
to
the
category
of
"
Important
Regional
Cancer
Risk
Contributor."
If
this
proves
to
be
correct,
we
hope
that
EPA
will
reflect
the
change
in
an
electronic
addendum
or
other
correction
of
NATA­
1996,
as
well
as
in
the
work
currently
under
way
to
prepare
NATA­
1999.

Thank
you
for
your
attention
to
this
matter.
If
you
have
any
questions,
please
let
me
know.

Very
truly
yours,

Neil
J.
King
Enclosures
cc:
K.
Jack
Kooyoomjian,
Ph.
D.
Introduction
Earlier
this
year,
EPA
published
its
Final
National­
Scale
Air
Toxics
Assessment
for
1996
("
NATA­
1996").
In
this
report,
EPA
categorized
nickel
compounds
as
an
Important
National
Cancer
Risk
Contributor
 
implying
that
more
than
25
million
people
live
in
census
tracts
where
exposures
to
nickel
compounds
pose
an
estimated
upper­
bound
lifetime
cancer
risk
exceeding
1
in
a
million.
This
categorization
was
predicated
on
three
major
assumptions:

1.
That
the
utilization
of
a
Unit
Risk
Estimate
(
URE)
of
4.8
x
10­
4
(
per
µ
g/
m3)
derived
solely
for
nickel
subsulfide
is
an
appropriate
basis
upon
which
to
categorize
the
contributing
cancer
risk
for
all
nickel
compounds
once
a
"
speciation
adjustment"
 
reflected
in
assumptions
(
2)
and
(
3)
below
 
is
made
to
account
for
the
mix
of
nickel
compounds
actually
present
in
ambient
air.

2.
That
65%
of
nickel
in
the
ambient
air
is
in
insoluble
form.

3.
That
all
of
this
65%
can
(
conservatively)
be
deemed
to
be
"
crystalline
nickel,"
which
EPA
appears
to
equate
with
nickel
subsulfide.

The
present
comments,
submitted
on
behalf
of
the
Nickel
Producers
Environmental
Research
Association
(
NiPERA),
the
Nickel
Development
Institute
(
NiDI),
and
Inco
United
States,
Inc.,
discuss
each
of
these
assumptions
and
whether
it
is
appropriate
to
use
them
in
characterizing
population
cancer
risks
attributable
to
nickel
compounds
in
the
ambient
air.
Alternative
methods
for
determining
the
appropriate
basis
on
which
to
characterize
these
risks
are
presented.

Background
In
1986,
the
EPA
published
a
Health
Assessment
Document
(
HAD)
for
Nickel
and
Its
Compounds.
In
this
document,
nickel
species
were
categorized
with
respect
to
potential
carcinogenicity,
and
unit
risk
estimates
for
carcinogenic
nickel
species
were
derived.
At
that
time,
the
species
determined
by
the
Agency
to
be
carcinogenic
were
nickel
refinery
dust
from
pyrometallurgical
sulfide
nickel
matte
refineries
and
nickel
subsulfide.
Nickel
carbonyl
was
found
to
be
a
"
probable"
carcinogen
based
on
certain
animal
data.
No
other
nickel
compounds
were
classified
as
being
carcinogenic,
although
their
carcinogenic
potential
was
discussed.

A
URE
of
2.4
x
10­
4
was
derived
for
nickel
refinery
dust
based
upon
an
analysis
of
data
relating
to
carcinogenic
risk
in
five
cohorts
employed
in
the
refining
of
1
Huntington,
West
Virginia
refinery
workers
exposed
to
nickel
subsulfide,
Huntington
workers
not
exposed
to
nickel
subsulfide
(
referred
to
as
"
non­
refinery
workers"),
Copper
Cliff
Ontario
Canada
refinery
workers,
Clydach,
Wales
refinery
workers,
and
Kristiansand,
Norway
refinery
workers.

2
nickel.
1
Unit
risk
estimates
were
calculated
for
each
of
the
cohorts,
and
the
midpoint
of
these
estimates
(
2.4
x
10­
4)
was
selected
as
characterizing
the
risk
of
nickel
refinery
dust
overall.
Because
nickel
subsulfide
was
thought
to
be
the
principal
carcinogenic
agent
in
refinery
dust,
EPA
then
multiplied
the
URE
that
it
had
calculated
for
nickel
refinery
dust
by
a
factor
of
2
to
account
for
what
the
Agency
believed
at
that
time
was
"
roughly,
the
50%
nickel
subsulfide
composition
of
refinery
dust."
(
Nickel
HAD
at
page
8­
218.).
This
resulted
in
an
artificially
constructed
URE
of
4.8
x
10­
4
(
per
µ
g/
m3)
for
nickel
subsulfide.

In
addition
to
deriving
UREs,
the
Nickel
HAD
also
reported
on
nickel
levels
in
the
ambient
air.
The
composition
of
nickel
in
the
ambient
air
varied
according
to
the
major
industrial
sources
emitting
nickel.
Particles
found
in
the
ambient
air
as
a
result
of
oil
and
coal
combustion
(
the
largest
source
contributor
to
nickel
in
the
air)
appeared
to
be
predominantly
in
the
form
of
nickel
sulfate,
with
lesser
amounts
of
nickel
oxide
and
complex
metal
oxides
containing
nickel
(
Henry
and
Knapp,
1980;
Dietz
and
Wieser,
1983).
Nickel
emissions
from
metallurgical
processes
(
e.
g.
steel
manufacturing,
nickel
alloy
manufacturing,
iron
and
steel
foundries)
were
found
to
be
in
the
form
of
complex
oxides
of
nickel
and
other
metals
and
metallic
nickel
(
Page,
1983;
Koponen
et
al.,
1981).
Emissions
from
chemical
and
catalyst
manufacturing,
including
plating,
appeared
to
be
combinations
of
soluble,
oxidic,
and
metallic
nickel
(
Radian
Corporation,
1983).
Emissions
from
primary
nickel
production
were
deemed
inconsequential
as
only
one
nickel
mine
operated
in
the
U.
S.
at
that
time.
This
mine
has
since
been
closed.
In
summary,
nickel
subsulfide
was
not
found
to
be
present
in
a
significant
amount
in
any
of
the
exposure
scenarios
described
above.

Selection
of
an
Appropriate
URE
and
Speciation
Adjustment
As
noted
above,
EPA
used
the
"
contrived"
URE
for
nickel
subsulfide
(
4.8
x
10­
4)
with
a
"
speciation
adjustment"
to
characterize
the
carcinogenic
risk
posed
by
nickel
compounds
in
the
ambient
air.
The
speciation
adjustment
was
based
on
the
assumption
that
insoluble
compounds
constitute
65%
of
nickel
in
the
ambient
air
and
that
all
of
this
insoluble
nickel
is
"
crystalline"
(
by
which
EPA
apparently
means
to
suggest
that
the
insoluble
nickel
is
nickel
subsulfide).
The
URE
for
nickel
subsulfide
was
then
multiplied
by
0.65
to
derive
a
URE
(
3.1
x
10­
4)
that
was
applied
to
the
exposure
concentrations
of
total
nickel
species
in
order
to
develop
the
risk
characterization
for
nickel
compounds
in
NATA­
1996.

We
believe
this
approach
is
not
well­
founded,
for
two
reasons.
First,
in
contrast
to
the
URE
for
nickel
refinery
dust
(
which
was
based
directly
upon
actual
human
data
involving
cancer
risks
for
workers
exposed
to
nickel
refinery
dust),
the
URE
for
nickel
subsulfide
was
artificially
derived
 
i.
e.,
it
was
not
based
upon
actual
data
for
a
cohort
of
workers
who
were
exposed
exclusively
to
nickel
subsulfide
(
or
even
to
a
mixture
of
compounds
in
which
the
nickel
subsulfide
component
2
As
of
this
date,
EPA
has
not
completed
an
evaluation
of
the
potential
carcinogenicity
of
soluble
nickel
compounds.
See
IRIS
Summary
for
Nickel,
Soluble
Salts.
However,
under
the
cosponsorship
of
EPA,
Toxicology
Excellence
for
Risk
Assessment
("
TERA")
critically
reviewed
all
the
relevant
evidence
in
1999
and,
in
a
peer
reviewed
report,
concluded
that:
(
1)
"
water­
soluble
salts
of
nickel
are
distinctly
different
from
water­
insoluble
nickel
compounds
with
respect
to
carcinogenic
potential";
(
2)
the
carcinogenicity
of
inhaled
soluble
nickel
compounds
"
cannot
be
determined";
and
(
3)
"
quantitative
estimates
of
cancer
risk
from
the
inhalation
of
soluble
nickel
compounds
.
.
.
are
not
recommended."
TERA,
1999
at
113,
116.
These
conclusions
are
consistent
with
the
results
of
NTP
inhalation
bioassays
in
which
soluble
nickel
showed
no
evidence
of
carcinogenicity
(
NTP
1996b).
See
note
4
infra.

3
was
well
characterized).
Hence,
only
limited
confidence
can
be
placed
in
the
URE
for
nickel
subsulfide
as
the
basis
to
estimate
the
carcinogenic
risk
that
nickel
compounds
in
the
ambient
air
pose
to
the
general
population
whose
exposures
to
nickel
subsulfide
are
negligible
or
non­
existent.

Second,
even
if
one
could
be
more
confident
about
the
URE
for
nickel
subsulfide,
it
is
perfectly
clear
that
nickel
subsulfide
does
not
constitute
anything
like
65%
of
the
nickel
species
in
ambient
air.
As
noted
above,
data
in
the
Nickel
HAD
indicated
that
the
predominant
species
from
the
important
nickel­
emitting
sources
in
the
U.
S.
are
soluble
nickel
compounds
(
predominantly
nickel
sulfate),
oxidic
nickel
compounds
(
including
complex
oxides
of
nickel
and
other
metals),
and
some
metallic
nickel.
No
significant
source
of
nickel
subsulfide
was
identified.
More
recent
studies
employing
various
analytical
methods
suggest
that,
if
present
at
all,
sulfidic
nickel
exists
below
the
limit
of
detection
(
0.5
­
2%
of
total
nickel
emissions)
(
EPRI,
1999;
Galbreath
et
al.,
2000).
In
another
study
in
Germany,
only
6%
of
total
ambient
nickel
was
found
to
be
sulfidic
(
Füchtjohann
et
al.,
2001).
Consequently,
EPA's
65%
assumption
overstates
the
nickel
subsulfide
component
of
nickel
species
in
ambient
air
by
an
order
of
magnitude
or
more.

That
said,
we
agree
with
EPA's
approach
of
characterizing
nickel­
related
cancer
risk
on
the
basis
of
the
insoluble
fraction
of
nickel
compounds
in
ambient
air2.
We
also
believe
it
is
not
unreasonable
to
assume
that,
as
a
conservative
upper
bound,
65%
of
nickel
found
in
the
ambient
air
may
be
insoluble
compounds
 
though
that
is
almost
certainly
too
high.
A
recent
study
suggests
that
the
percent
contribution
of
soluble
nickel
from
oil­
fired
utility
boilers
(
a
major
source
contributor
of
nickel
to
the
ambient
air)
could
be
much
higher
than
35%,
thereby
decreasing
the
total
amount
of
nickel
that
may
be
found
as
insoluble
species
(
Galbreath
et
al.,
2000).
Moreover,
not
all
insoluble
nickel
in
ambient
air
will
be
nickel
compounds.
Some
of
the
insoluble
nickel
in
ambient
air
is
metallic
nickel.
Emissions
from
metallurgical
sources
and
certain
chemical
sources
are
bound
to
contain
some
metallic
nickel.
Indeed,
a
recent
paper
speciating
nickel
in
the
ambient
air
suggests
that
up
to
10%
of
total
nickel
may
be
metallic
nickel,
rather
than
nickel
compounds
(
Füchtjohann
et
al.,
2001).
Thus,
a
speciation
adjustment
of
50%,
rather
than
65%,
probably
would
be
more
appropriate
to
3
Metallic
nickel
has
not
been
shown
to
be
carcinogenic
in
humans
(
Cox
et
al.,
1981;
Enterline
and
Marsh,
1982;
Cragle
et
al.,
1984;
ICNCM,
1990;
Arena
et
al.,
1998;
Moulin
et
al.,
2000,
Egedhal
et
al.,
2001)
and
therefore
should
not
be
included
in
the
calculation
of
potentially
carcinogenic
insoluble
nickel
species.

4
Recent
NTP
and
mechanistic
studies
support
the
contention
that,
of
the
various
nickel
species,
nickel
subsulfide
is
the
most
potent
carcinogen,
with
oxidic
nickel
being
less
potent,
and
soluble
nickel
showing
no
evidence
of
carcinogenicity
(
NTP,
1996a,
1996b,
1996c;
Costa,
1991;
Oller
et
al.,
1997;
Haber
et
al.,
2000).

4
account
for
the
percent
total
mass
of
nickel
presumed
to
be
insoluble
compounds.
3
Whether
insoluble
compounds
are
deemed
to
constitute
50%
or
65%
of
total
nickel
in
ambient
air,
the
URE
for
nickel
refinery
dust,
rather
than
the
"
contrived"
URE
for
nickel
subsulfide,
should
be
used
as
the
basis
to
characterize
potential
cancer
risks
to
the
general
population
associated
with
the
presence
of
insoluble
nickel
compounds
in
the
ambient
air.
The
URE
for
refinery
dust
is
a
more
reasonable
surrogate
to
use
for
this
purpose
for
two
reasons:
(
1)
In
contrast
to
the
URE
for
nickel
subsulfide,
it
is
derived
directly
from
epidemiological
data;
and
(
2)
the
composition
of
refinery
dust
(
mainly
oxidic
nickel,
with
lesser
amounts
of
sulfidic,
metallic,
and
soluble
nickel)
is
more
comparable
to
the
composition
of
nickel
compounds
in
the
ambient
air
than
nickel
subsulfide
alone.
Even
this
approach
would
be
conservative,
because
the
URE
for
nickel
refinery
dust
reflects,
in
part,
the
carcinogenic
potency
of
nickel
subsulfide
(
the
most
potent
of
nickel
compounds
believed
to
be
carcinogenic),
and
nickel
subsulfide
is
a
much
more
significant
component
of
refinery
dust
than
it
is
of
nickel
species
in
the
ambient
air.
4
Applying
a
65%
insoluble
nickel
"
speciation
adjustment"
to
the
URE
for
nickel
refinery
dust
(
2.4
x
10­
4)
produces
a
URE
value
of
1.6
x
10­
4
(
per
µ
g/
m3).
If
a
50%
insoluble
nickel
"
speciation
adjustment"
were
employed,
the
resulting
URE
value
would
be
1.2
x
10­
4
(
per
µ
g/
m3).

Alternatively,
if
EPA
wished
to
use
a
cohort
whose
nickel
exposures
were
more
comparable
to
the
composition
of
nickel
species
in
the
ambient
air
than
the
refinery
cohorts,
the
UREs
for
Huntington
non­
refinery
workers
could
be
considered.
These
workers
were
exposed
mainly
to
a
combination
of
oxidic,
metallic,
and
soluble
nickel
 
with
no
exposure
to
nickel
subsulfide.
UREs
for
this
cohort
range
from
9.5
x
10­
6
to
2.1
x
10­
5
(
per
µ
g/
m3)
(
EPA,
1986).
The
midpoint
of
this
range
is
1.5
x
10­
5.

Conclusion
Since
we
do
not
have
the
exposure
modeling
data
that
EPA
used
in
developing
its
risk
characterization
for
nickel
compounds
in
NATA­
1996,
we
are
not
in
a
position
to
say
whether
use
of
a
more
appropriate
URE
value
and/
or
"
speciation
adjustment"
would
change
the
risk
category
in
which
nickel
compounds
were
placed.
But,
even
without
lowering
the
"
speciation
adjustment"
to
50%,
use
of
5
If
the
URE
for
the
Huntington
non­
refinery
workers
were
used,
an
even
greater
reduction
would
be
expected.

5
the
URE
for
nickel
refinery
dust,
rather
than
the
URE
for
nickel
subsulfide,
likely
would
reduce
by
half
the
number
of
people
living
in
census
tracts
where
exposures
to
nickel
compounds
are
estimated
to
pose
an
upper­
bound
lifetime
cancer
risk
exceeding
1
in
a
million.
5
That
alone
might
downgrade
the
categorization
of
nickel
compounds
from
Important
National
Cancer
Risk
Contributor
to
Important
Regional
Cancer
Risk
Contributor
 
indicating
that
nickel
compounds
in
the
ambient
air
do
not
pose
a
risk
of
concern
to
the
U.
S.
population
on
a
national
basis,
although
pockets
of
risk
may
exist
regionally.
We
request
that
EPA
perform
the
appropriate
calculations
and
reflect
the
results
in
an
addendum
or
other
correction
of
NATA­
1996,
as
well
as
in
the
work
that
is
being
done
to
develop
NATA­
1999.

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