Document ID: EPA-HQ-OAR-2002-0056-6214
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-03-15T05:00Z

RESPONSE
TO
SIGNIFICANT
PUBLIC
COMMENTS
ON
THE
PROPOSED
CLEAN
AIR
MERCURY
RULE
Received
in
response
to:

Proposed
National
Emission
Standards
for
Hazardous
Air
Pollutants;
and,
in
the
Alternative,
Proposed
Standards
of
Performance
for
New
and
Existing
Stationary
Sources:
Electric
Utility
Steam
Generating
Units
(
69
FR
4652;
January
30,
2004)

Supplemental
Notice
for
the
Proposed
National
Emission
Standards
for
Hazardous
Air
Pollutants;
and,
in
the
Alternative,
Proposed
Standards
of
Performance
for
New
and
Existing
Stationary
Sources:
Electric
Utility
Steam
Generating
Units
(
69
FR
12398;
March
16,
2004)

Proposed
National
Emission
Standards
for
Hazardous
Air
Pollutants;
and,
in
the
Alternative,
Proposed
Standards
of
Performance
for
New
and
Existing
Stationary
Sources,
Electric
Utility
Steam
Generating
Units:
Notice
of
Data
Availability
(
69
FR
69864;
December
1,
2004)

Docket
Number
OAR­
2002­
0056
9.0
NODA
Comments
US
Environmental
Protection
Agency
Emissions
Standards
Division
Office
of
Air
Quality
Planning
and
Standards
Research
Triangle
Park,
North
Carolina
27711
15
March
2005
i
General
Outline
1.0
INTRODUCTION
AND
BACKGROUND
2.0
APPLICABILITY
AND
SUBCATEGORIZATION
3.0
PERFORMANCE
STANDARDS
FOR
COAL­
FIRED
ELECTRIC
UTILITY
STEAM
GENERATING
UNITS
4.0
PERFORMANCE
STANDARDS
FOR
OIL­
FIRED
ELECTRIC
UTILITY
STEAM
GENERATING
UNITS
5.0
MERCURY
CAP­
AND­
TRADE
PROGRAM
6.0
MERCURY
EMISSIONS
MONITORING
7.0
IMPACT
ESTIMATES
8.0
COMPLIANCE
WITH
EXECUTIVE
ORDERS
AND
STATUTES
9.0
NODA
10.0
OTHER
Appendix
A
LIST
OF
COMMENTERS
9­
1
9.0
NODA
COMMENTS
A.
Electric
Power
Sector
Modeling
General
Comments
concerning
Electric
Power
Sector
Modeling
Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
the
EPA
NODA
provides
what
is
stated
as
a
summary
of
the
model
results
reported
by
CRA
in
comments
submitted
by
both
the
commenter
and
EPRI
in
June
2004.
In
presenting
its
summary
(
Table
4
of
the
NODA),
EPA
chose
to
report
the
EPMM
emissions
estimated
for
2018­
2019
as
if
they
were
the
2020
emissions
estimate
too.
This
is
incorrect,
and
hides
the
fact
that
EPMM
scenarios
projected
that
Hg
emissions
would
fall
to
15
tons
by
2020.
It
is
extraordinary
that
EPA
would
choose
to
state
a
completely
different
number
in
the
summary
table
than
was
reported
by
the
original
investigators,
even
if
EPA
had
reason
to
dispute
the
basis
for
the
finding
of
the
original
investigators.
Nevertheless,
even
the
rationale
EPA
provides
for
listing
a
very
different
emissions
result
than
was
originally
reported
is
wrong
and
reflects
a
misunderstanding
of
how
optimizing
models
function.

The
NODA
states:
"
EPA
notes
the
commenter's
projected
emissions
of
15
tons
in
2020
appear
to
be
an
artifact
of
the
grouping
of
the
2020
run
year
with
the
model
end
run
year
of
2040.
EPA
maintains
that,
in
a
leastcost
solution
model
like
EPMM,
the
model
would
solve
for
the
cap
in
the
final
run
year
grouping.
Therefore,
Hg
emissions
reported
for
trading
scenarios
in
the
table
below
[
i.
e.,
Table
4
of
the
NODA]
are
those
projected
for
2019,
because
EPA
believes
they
better
represent
emissions
in
2020."

The
commenter
further
stated
that
it
is
not
true
that
optimizing
models
like
EPMM
force
emissions
to
reach
the
cap
in
their
end
year.
Optimization
does
require
that
there
be
zero
banked
emissions
at
the
end
of
the
model
horizon,
but
it
is
perfectly
possible
to
enter
the
last
modeled
period
(
i.
e.,
2020­
39
in
this
case)
with
a
positive
bank
balance.
If
this
happens,
then
the
model
will
select
just
enough
controls
for
that
last
period
so
that
emissions
will
last
exactly
the
length
of
the
last
period,
and
be
exactly
exhausted
at
the
end
of
the
terminal
modeled
period.
For
example,
if
the
last
modeled
period
is
10
years
long,
a
least­
cost
solution
might
be
to
enter
that
last
10­
year
period
with
10
tons
in
the
bank,
which
would
be
used
up
at
the
rate
of
1
ton
per
year.
Controls
would
be
applied
at
the
beginning
of
the
terminal
period
to
bring
emissions
to
exactly
1
ton
above
the
final
level
of
the
cap.
At
the
end
of
the
10
years,
emissions
would
have
to
be
reduced
to
exactly
the
level
of
the
cap.
Thus,
when
the
model
says
emissions
are
exactly
at
the
cap
at
the
beginning
of
the
terminal
period,
this
is
because
achieving
the
cap
by
that
first
year
(
rather
than
by
the
last
year
of
that
period)
is
lower­
cost
than
the
only
alternative,
which
would
be
to
make
yet
greater
reductions
in
one
or
more
of
the
earlier
periods
that
would
enable
entry
into
the
terminal
period
with
a
positive
bank­
balance.
9­
2
The
commenter
also
noted
that
another
way
to
state
this
is
that
emissions
cannot
be
above
the
final
level
of
the
cap
(
15
tons
in
this
case)
during
any
year
of
the
terminal
period
unless
there
is
a
positive
balance
of
banked
emissions
at
the
end
of
the
year
just
prior
to
the
start
of
the
terminal
period.
This
provides
yet
another
way
to
demonstrate
that
EPA
is
wrong
when
it
states
that
emissions
in
2020
would
be
closer
to
the
level
projected
for
2019
than
to
15
tons.
Table
1
shows
the
emissions
projected
in
each
modeled
period
of
EPMM
for
the
base
Hg
cap
scenario,
and
the
level
of
the
cap
that
applies
in
each
time
period.
The
last
column
shows
the
resulting
balance
in
the
Hg
allowance
bank
at
the
end
of
each
of
the
modeled
periods.
It
is
quite
clear
that
if
emissions
follow
the
path
selected
for
each
of
the
modeled
periods
prior
to
the
terminal
period
of
2020,
then
there
will
be
no
allowances
in
the
bank
at
the
start
of
2020,
and
emissions
must
be
15
tons
from
2020
onwards.
This
is
not
an
"
artifact"
of
the
fact
that
2020
is
the
first
year
of
the
terminal
model
period.

Table
1.
Bank
Balances
Under
EPMM
Scenario
for
Proposed
Mercury
Cap*

Year
Hg
Emissions
(
tons
per
year)
Hg
Cap
in
Same
Time
Period
(
tons
per
year)
Annual
Rate
of
Accumulation
in
the
Bank
(
tons
per
year)
Hg
Bank
at
Beginning
of
Period
(
tons)

2004­
2007
44.6
na
na
na
2008­
2009
43.3
na
na
na
2010­
2011
34.0
34.0
0.0
0.0
2012­
2014
32.2
34.0
+
1.8
0.0
2015­
2017
29.9
34.0
+
4.1
5.3
2018­
2019
23.9
15.0
­
8.9
17.7
2020­
2039
15.0
15.0
0.0
0.0
*
Values
in
Table
1
are
from
the
scenario
that
applies
no
reduction
in
variable
O&
M
costs
of
ACI,
i.
e.,
the
standard
case
in
Table
4
of
NODA.
Results
are
comparable
for
all
the
other
EPMM
cap­
and­
trade
scenarios
reported
in
NODA.

It
is
therefore
impossible
to
reconcile
the
emissions
and
control
actions
that
the
model
selects
from
2004­
2018
with
any
emissions
level
other
than
15
tons
starting
in
2020
(
and,
of
course,
lasting
at
15
tons
thereafter).
If
emissions
in
2020
were
to
be
24
tons,
as
EPA
has
incorrectly
asserted,
then
the
bank
would
have
to
be
drawn
down
to
negative
9
tons
in
2020
alone.
This
is
not
how
EPMM
works.
If
EPMM
were
to
find
it
cost­
effective
to
delay
compliance
with
the
cap
beyond
2020,
it
would
have
to
reduce
emissions
by
much
larger
amounts
prior
to
2020.
It
has
the
option
to
do
this,
but
the
model
chooses
not
to.
The
model
finds
that
a
time
path
of
emissions
that
entails
reaching
exactly
15
tons
by
the
beginning
of
2020
is
the
leastcost
solution.
This
may
not
be
consistent
with
EPA's
IPM
results,
but
the
commenter's
June
2004
submission
(
see
OAR­
2002­
0056­
2929)
provides
an
extensive
explanation
of
the
differences
in
our
and
EPA's
model
assumptions
that
explain
that
difference.

Since
the
preceding
explanation
may
be
difficult
for
non­
specialists
to
follow,
it
is
useful
to
demonstrate
that
EPA
is
in
error
by
employing
evidence
in
the
model
runs
themselves.
Table
2
9­
3
lists
the
SO
2
emissions
that
were
reported
for
the
same
scenario,
along
with
the
caps
applied.
As
in
Table
1,
the
last
column
shows
the
banked
allowances
(
which
include
the
amount
assumed
to
be
in
the
Title
IV
bank
just
before
the
beginning
of
the
first
modeled
year,
2004).
The
emissions
of
SO
2
do
not
exactly
meet
the
SO
2
cap
at
the
beginning
of
2020,
as
they
do
in
the
same
model
run
for
Hg
(
Table
1).
Entering
the
terminal
period
of
2020­
2039,
there
are
769,644
tons
of
SO
2
in
the
bank.
As
the
model
does
force
this
bank
to
be
exactly
used
up
by
the
end
of
that
terminal
period,
and
at
a
constant
level
throughout
that
period,
emissions
exceeds
the
cap
by
exactly
769,644/
20
tons
(
i.
e.,
by
38,482
tons)
in
2020
and
in
each
of
the
next
20
years.
Thus,
a
counterexample
exists
in
the
very
same
model
runs
that
EPA
was
summarizing
to
EPA's
assertion
that
"
the
model
would
solve
for
the
cap
in
the
final
run
year
grouping".

Table
2.
SO2
Emissions
and
Bank
Balances
Under
EPMM
Scenario
for
Proposed
Mercury
Cap*

Year
SO
2
Emissions
(
tons
per
year)
SO
2
Cap
in
Same
Time
Period
(
tons
per
year)
Annual
Rate
of
Accumulation
in
the
Bank
(
tons
per
year)
SO
2
Bank
at
Beginning
of
Period
(
tons)

2004­
2007
9,340,664
9,480,000
139,336
8,000,000
2008­
2009
8,100,088
9,480,000
1,379,912
8,557,344
2010­
2011
6,071,281
5,086,400
­
984,881
1l,
317,168
2012­
2014
5,552,485
5,086,400
­
466,085
9,347,406
2015­
2017
4.476,623
3,798,600
­
1,678,023
7,949,151
2018­
2019
4,871
,319
3,798,600
­
1,072,719
2,915,082
2020­
2039
3,837,082
3,798,600
­
38,482
769,644
*
Values
in
Table
2
are
from
the
scenario
that
applies
no
reduction
in
variable
O&
M
costs
of
ACI,
i.
e.,
the
standard
case
in
Table
4
of
NODA.
Results
are
comparable
for
all
the
other
EPMM
cap­
and
trade
scenarios
reported
in
NODA;
we
use
this
case
here
because
it
is
one
for
which
SO
2
emissions
were
reported
in
our
earlier
submissions,
and
which
EPA
therefore
had
the
ability
to
review.

Nevertheless,
there
are
some
good
reasons
to
de­
emphasize
reported
model
results
associated
with
the
terminal
model
period
of
models
such
as
EPMM
and
IPM.
CRA
did
not
choose
the
time
periods
in
EPMM
with
the
goal
of
being
able
to
report
precise
estimates
of
emissions
specifically
for
2020,
nor
even
with
an
expectation
that
any
year
after
2018
would
have
any
interest.
Given
that
substantial
emphasis
has
since
been
focused
on
whether
the
Phase
II
Hg
cap
of
15
tons
might
be
fully
attained
by
about
2020,
the
commenter
felt
it
is
reasonable
to
allow
a
time
step
for
2020
that
is
not
the
terminal
time
period
of
the
EPMM
model.
Since
release
of
the
NODA,
the
commenter
added
another
time
step
to
EPMM
that
starts
in
2030
and
represents
the
final
20­
year
period
(
through
2049).
Results
for
the
2030
terminal
time
step
can
be
deemphasized
without
losing
information
about
the
likely
emissions
in
the
2020
time
frame.

The
commenter
ran
the
extended­
horizon
version
of
EPMM
for
the
same
Hg
cap­
andtrade
assumptions
that
were
reported
in
the
NODA
Table
4
as
with
"
improved
ACI
costs."
Table
3
provides
the
emissions
values
from
the
original
run
when
2020
was
the
beginning
of
the
terminal
9­
4
model
period,
and
from
the
new
run
which
differs
only
in
that
2030
is
now
the
beginning
of
the
terminal
model
period.
These
emissions
paths
are
illustrated
in
Figure
1.
The
emissions
paths
are
very
similar.
Most
importantly,
emissions
in
2020,
even
when
it
is
not
a
terminal
period
of
the
model),
are
still
very
close
to
the
final
cap
of
15
tons
(
i.
e.,
they
are
15.4
tons).
Results
using
a
version
of
EPMM
where
2020
is
not
the
terminal
period
further
demonstrate
that
EPA
was
not
justified
in
replacing
our
reported
2020
emissions
values
on
an
ad
hoc
basis
with
our
reported
2019
emissions
level.

All
the
available
models
(
EPMM
and
IPM
alike)
provide
only
an
approximation
of
what
are
emissions
paths
continuously
changing
in
time
because
they
are
forced
by
computational
resources
to
simulate
discrete
multi­
year
time
steps
rather
than
the
more
realistic
path
of
gradual
year­
over­
year
emissions
reductions.
The
actual
optimal
time
path
of
emissions
will
be
smoother,
and
this
means
that
emissions
in
2020
might
be
somewhat
higher
than
in
2021,
and
in
each
of
the
remaining
years
in
the
2020
time
period.
However,
one
must
recall
that
the
requirement
of
a
nonnegative
bank
of
Hg
allowances
imposes
an
important
constraint
on
emissions
after
2018.
For
example,
the
EPMM
model
indicates
that
emissions
in
2020­
2029
would
be
a
constant
15.4
tons.
The
bank
going
into
that
time
period
is
3.6
tons.
Thus,
even
if
(
both
cases
simulate
the
proposed
Hg
cap­
and­
trade
scenario
and
assume
a
2.5
percent
per
annum
reduction
in
variable
O
and
M
cost
of
ACI
control
technologies)

Table
3.
Hg
Emissions
Projections
Differing
Terminal
Model
Periods
Terminal
period
starting
2020
(
June
submission)
Terminal
period
starting
2030
(
This
submission)
2004
44.4
44.6
2008
43.2
43.1
2010
34.0
34.0
2012
32.6
32.3
2015
29.4
28.9
2018
24.1
23.5
2020
15.0
15.4
2030
15.0
15.0
9­
5
emissions
in
2020
were
to
remain
above
emissions
in
following
years
of
the
2020­
2029
time
step,
those
2020
emissions
could
not
exceed
18.6
tons
(
i.
e.,
3.6
tons
above
the
cap).
Further,
if
they
were
that
high
in
2020,
then
the
15
ton
cap
would
have
to
be
met
exactly
from
2021
onwards.
In
other
words,
although
ad
hoc
reasoning
could
lead
one
to
conclude
that
2020
emissions
might
be
as
high
as
18.6
tons,
such
ad
hoc
reasoning
must
also
accept
that
emissions
only
one
year
later
(
i.
e.,
from
2021
onwards)
must
meet
the
Phase
II
cap.

Thus,
modeling
based
on
the
assumptions
the
commenter
documented
in
June
2004
(
see
OAR­
2002­
0056­
2929)
indicates
that
either
the
Phase
II
cap
will
be
met
within
all
but
a
fraction
of
a
ton
by
2020,
or
if
it
is
exceeded
by
any
significant
amount
in
2020,
then
it
will
be
exactly
attained
within
one
or
two
years
after
that.

Response:

Based
on
the
commenter's
additional
analysis
submitted
into
the
record,
EPA
agrees
that
commenter's
analysis
projected
emissions
to
be
15.4
tons
in
2020
for
the
modeled
Hg
trading
scenario.
However,
we
disagree
with
the
commenter's
conclusion
that
we
misunderstand
how
optimizing
models
function.
In
the
NODA
in
which
EPA
summarized
the
commenter's
analysis
submitted
to
the
record,
EPA
did
not
state
optimizing
models
like
EPMM
force
emissions
to
reach
the
cap
in
their
end
year,
rather
we
stated
that
optimizing
models
solve
for
the
cap.
That
is
to
say,
we
agree
with
the
commenter
statement
that
optimization
does
require
that
there
be
zero
banked
emissions
at
the
end
of
the
model
horizon,
i.
e,
solve
for
the
cap.
EPA
also
agrees
with
the
commenter
that
it
is
possible
to
enter
the
last
modeled
period
(
i.
e.,
2020­
39
in
this
case)
9­
6
with
a
positive
bank
balance.
EPA
anticipated
a
more
gradual
withdrawal
of
the
bank
given
that
additional
Hg
controls
are
being
installed
in
the
2018­
2019
timeframe.
This
is
similar
to
what
EPA
sees
in
it
own
modeling
and
what
the
commenter
is
projecting
in
its
SO
2
modeling.
However,
EPA
does
not
dispute
the
additional
data
the
commenter
submitted
on
the
bank
withdrawal
in
its
modeling.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
stated
that
there
is
only
one
possible
reason
why
bank­
balance
accounting
may
not
be
applicable
to
the
argument
above:
the
so­
called
"
safety
valve."
The
concept
of
the
"
safety
valve"
is
originally
one
of
providing
a
formal,
legislated
ceiling
on
allowance
prices.
It
was
first
introduced
in
carbon
policy
proposals.
EPA's
proposed
rule
includes
a
concept
that
EPA
calls
a
"
safety
valve,"
but
which
would
not
be
implemented
in
the
manner
necessary
for
it
to
function
as
a
price
ceiling.
In
EPA's
proposed
cap­
and­
trade
rule
in
the
Clean
Air
Mercury
Rule
(
CAMR),
companies
may
"
borrow"
against
their
own
future
allocations
of
Hg
allowances
if
prices
exceed
some
pre­
specified
amount.
Borrowing
against
one's
future
fixed
allocation
is
a
substantially
different
matter
than
having
the
government
issuing
as
many
additional
allowances
as
might
be
demanded
for
a
fixed
price.
The
former
maintains
the
constraint
of
the
cap
unchanged
across
a
set
of
years,
whereas
the
latter
actually
loosens
the
cap.
The
former
creates
far
less
flexibility,
because
by
reining
in
allowance
prices
in
one
year,
it
only
increases
allowance
prices
(
by
reducing
available
allowances)
in
a
later
year.
In
all,
the
concept
that
EPA
calls
a
"
safety
valve"
in
its
proposed
rule
is
not
a
price
cap
at
all.
More
importantly,
it
retains
a
binding
constraint
on
cumulative
Hg
emissions,
regardless
of
the
possible
future
marginal
cost
of
meeting
that
cumulative
constraint.
Thus,
it
remains
correct
for
a
discussion
about
the
future
time
path
of
emissions
under
the
Hg
cap­
and­
trade
proposal
to
assume
that
sustained
negative
bank
balances
are
not
cost­
effective.

Response:

EPA
is
not
finalizing
a
safety
valve
provision
in
the
cap­
an­
trade
rulemaking.
See
final
rule
preamble
for
further
rationale.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
the
NODA
states
that
the
commenter's/
EPRI
scenarios
were
not
performed
with
a
safety
valve.
First,
to
the
extent
that
the
cumulative
cap
remains
inviolate,
as
described
in
the
formal
EPA
proposal,
the
scenarios
do
approximate
its
effect.
Second,
even
if
one
were
to
assume
a
safety
valve
that
could
be
interpreted
as
a
literal
cap
on
Hg
prices,
that
safety
valve
would
not
be
exceeded
in
any
scenario
the
commenter
ran
except
the
one
assuming
no
cost
reduction
on
Hg
control
technology
at
all
during
the
next
15
years.
Thus,
CRA's
runs
and
results
are
consistent
with
even
a
true
safety
valve
implementation.
Nevertheless,
merely
having
the
ability
to
borrow
against
one's
own
future
fixed
allocation
would
not
place
a
ceiling
on
allowance
prices.

Response:

EPA
agrees
with
the
commenter.
9­
7
Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
the
NODA
also
understates
the
degree
of
attention
that
CRA's
analysis
gave
to
alternative
possible
rates
of
technological
improvement.
EPA
implies
at
p.
69869
of
the
NODA
that
CRA's
analysis
included
only
two
alternative
assumptions
about
the
rate
of
technological
improvement,
(
i.
e.,
2.5
percent
annual
reduction
in
variable
O&
M
costs
and
0
percent).
In
fact,
CRA
considered
five
different
sets
of
assumptions
about
potential
technological
improvements,
including
none
at
all,
and
varying
rates
of
future
reductions
in
variable
O&
M
costs,
and
in
capital
costs
as
well
as
O&
M
costs.
All
of
these
alternatives
were
presented
as
a
set,
to
emphasize
that
the
commenter
were
not
advocating
any
single
assumption,
but
only
to
convey
the
insight
that
technological
improvement
would
have
an
effect
on
projected
allowance
prices
(
while
having
little
or
no
impact
on
other
aspects
of
the
policy).

Response:

EPA
was
aware
of
the
commenter
other
analyses,
but
limited
the
presentation
of
analysis
to
those
that
offered
comparisons
to
other
commenter's
analyses.
EPA
has
considered
all
the
information
submitted
by
the
commenter
in
the
final
rulemaking.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
in
OAR­
2002­
0056­
2578,
EPRI
reported
on
deposition
patterns
for
2020
that
were
developed
with
the
TEAM
model
using
unitspecific
emissions
projections
from
the
EPMM
model.
The
deposition
pattern
for
the
15
ton
cap­
and­
trade
scenario
indicated
larger
deposition
reductions
than
the
MACT
scenario
in
all
regions.
It
projected
the
largest
deposition
reductions
concentrated
in
the
area
of
the
Ohio
River
Valley
and
Middle
Atlantic
States,
which
had
moderately
high
projected
deposition
under
base
case
conditions.
These
results
suggested
that
there
was
no
reason
to
conclude
that
the
cap­
andtrade
policy
option
might
create
hypothetical
"
hot
spots,"
or
allow
hypothetically
existing
"
hot
spots"
to
continue
where
the
MACT
policy
option
would
not.

Nevertheless,
EPA
continues
to
express
concerns
with
the
possibility
of
hypothetical
"
hot
spots"
persisting
under
a
cap­
and­
trade
program.
In
particular,
there
have
been
suggestions
that
despite
projections
of
broad
regional
reductions
in
deposition,
there
might
still
be
a
few
individual
plants
that
are
large
emitters
that
might
not
individually
control
Hg
emissions,
and
which
could
pose
a
"
hot­
spot"
concern.
CRA
has
prepared
a
more
detailed
summary
of
the
plant­
by­
plant
emissions
changes
in
its
originally­
reported
Hg
cap­
and­
trade
scenario.
The
commenter
took
the
unit­
specific
emissions
for
2004
and
2020,
and
aggregated
them
to
obtain
plant­
wide
emissions,
which
best
represent
the
size
of
an
individual
utility
point­
source.
The
results
of
this
detailed
review
of
the
earlier
EPMM
results
are
summarized
in
Figure
2.

In
Figure
2,
each
dot
represents
one
of
the
401
coal
plants
in
the
modeled
data
base.
They
are
located
on
the
x­
axis
according
to
the
projected
2004
emissions
(
in
kg/
yr).
The
highest
emitting
plants
are
those
on
the
right
side
of
the
plot.
(
If
the
emissions
of
each
dot
are
summed
up,
the
total
is
equal
to
EPMM's
estimated
reference
case
US
utility
sector
Hg
emissions
in
2004:
47
tons,
or
42,800
kg.)
The
y­
axis
reveals
the
percent
Hg
reduction
at
each
plant
by
2020
in
the
9­
8
cap­
and­
trade
scenario,
when
total
emissions
are
reduced
to
15
tons,
or
13,636
kg.
This
figure
provides
a
way
of
screening
for
plants
that
might
pose
a
potential
concern
under
a
cap­
and­
trade
program
for
hypothesized
"
hot
spots."
That
is,
the
likeliest
plants
of
concern
would
be
those
that
are
large
emitters,
but
which
either
fail
to
control,
or
increase
their
emissions
as
a
result
of
the
flexibility
provided
by
cap­
and­
trade.

The
set
of
plants
that
emit
more
than
100
kg/
yr
(
i.
e.,
more
than
220
lb/
yr)
are
those
in
the
pink
triangular
area
of
Figure
2.
This
set
contains
37
percent
of
all
plants
(
150
plants),
and
accounts
for
about
75
percent
of
total
US
emissions
projected
in
the
2004
base
year.
All
plants
but
one
in
this
group
reduce
their
plant­
wide
emissions
by
at
least
20
percent,
and
most
by
over
60
percent;
in
fact,
the
average
projected
reduction
of
these
top
150
plants
is
76
percent.

The
single
plant
that
does
not
reduce
its
emissions
is
a
lignite­
burning
plant
that
already
has
a
fabric
filter
and
wet
FGD.
The
lignite
that
it
uses
has
a
relatively
low
Hg
content.
When
these
attributes
are
combined
with
our
assumption
that
ACI
only
reduces
remaining
Hg
by
75
percent
in
a
lignite
plant,
this
plant
faces
a
very
high
dollar­
per­
ton
removal
 
much
higher
than
that
projected
as
the
marginal
cost
of
control
in
the
Hg
allowance
market
when
the
cap
has
reached
15
tons.
Thus,
this
single
plant
among
all
the
top
150
emitters
relies
solely
on
allowance
purchases
in
response
to
the
15
ton
cap.
It
is
noteworthy
that
this
plant
is
projected
to
emit
the
same
quantity
of
Hg
under
the
proposed
MACT
policy
option
as
well,
because
its
estimated
current
emissions
rate
meets
the
MACT
rate
limit
proposed
for
lignite
plants.

Conclusions
are
much
the
same
even
when
we
consider
all
plants
emitting
more
than
50
kg/
yr
(
i.
e.,
more
than
110
lb/
yr).
This
set
of
plants
includes
89
more
plants
that
emit
between
50
and
100
kg/
yr
(
all
the
dots
within
the
green
rectangular
area
of
Figure
2)
as
well
as
the
150
plants
emitting
more
than
100
kg/
yr
considered
in
the
preceding
paragraph
(
the
dots
in
the
pink
area).
This
larger
group
of
239
plants
accounts
for
60
percent
of
all
plants
in
the
model
database,
and
as
a
set,
they
are
projected
to
account
for
90
percent
of
all
US
utility
emissions
in
the
2004
base
year.
(
Otherwise
stated,
all
the
remaining
plants
account
for
only
10
percent
of
US
emissions.)

Even
when
accounting
for
the
largest­
emitting
plants
that
emit
90
percent
of
all
utility
emissions,
almost
all
are
projected
to
control
their
emissions.
The
average
reduction
within
this
larger
set
is
74
percent.
As
can
be
seen
in
Figure
2,
there
are
only
6
plants
within
this
set
of
239
plants
that
do
not
have
a
financial
incentive
to
choose
to
reduce
their
emissions
in
the
face
of
a
15
ton
cap
on
utility
emissions.
Only
one
of
the
6
is
among
the
top
150
plants,
and
it
was
discussed
above.
Of
the
other
five:

°
Two
are
lignite
plants
identical
in
configuration
to
the
one
described
above,
emitting
primarily
elemental
Hg
(
Hg0).
These
two
plants
also
have
the
same
projected
emissions
under
the
MACT
option
as
under
the
cap­
and­
trade
option.

°
There
are
two
plants
that
are
projected
to
have
a
slight
increase
in
their
emissions
by
2020.
Both
of
these
already
have
a
wet
FGD
and
SCR
on
a
cold­
side
ESP
unit.
As
they
burn
a
bituminous
coal,
they
are
assumed
to
obtain
very
large
percentage
reductions
(
i.
e.,
85
percent)
due
to
the
existing
pollution
control
equipment
in
place.
Thus,
these
plants
face
relatively
high
dollars­
per­
ton
removed
from
their
only
remaining
control
option,
which
is
to
add
ACI.
The
slight
increase
in
Hg
emissions
results
when
these
plants
switch
from
a
9­
9
high­
sulfur
coal
to
a
blend
with
a
medium­
sulfur
coal
(
in
order
to
further
reduce
their
SO
2
emissions
as
the
price
of
SO
2
rises).
Small
increases
in
emissions
like
this
are
more
likely
to
occur
on
plants
that
already
have
the
highest
levels
of
co­
controls.
More
importantly,
however,
is
that
these
two
plants
also
increase
their
emissions
under
the
MACT
option.
That
is,
their
current
emissions
rate
is
already
below
the
2.0
lb/
tBtu
limit
required
by
the
proposed
MACT
option,
and
these
plants
have
even
less
financial
incentive
to
avoid
minor
Hg
emissions
increases
under
the
MACT
option
than
under
the
cap­
and­
trade
option.
(
EPRI's
comments
on
the
NODA
explore
the
local
deposition
implications
of
the
Hg
emissions
at
these
two
plants.
EPRI's
comments
report
that
the
projected
local
deposition
around
these
two
plants
actually
decreases
in
2020
despite
the
slight
increase
projected
from
these
plants
individually.
This
is
because
there
is
so
much
other
control
being
applied
to
the
many
coal­
fired
sources
that
surround
these
plants,
which
are
located
in
ECAR,
and
those
other
sources
also
affect
deposition
projected
within
the
respective
20
km
squares
where
these
plants
are
located.)

°
The
fifth
plant
is
the
lowest
emitter
among
those
that
do
not
change
their
Hg
emissions
at
all.
This
plant
has
an
existing
fabric
filter
and
wet
FGD.
This
is
a
western
plant
burning
a
blend
of
western
bituminous
and
subbituminous
coal.
Being
a
western
plant,
it
has
no
incentive
to
add
an
SCR
other
than
from
Hg
co­
benefits,
but
those
are
low
due
to
its
use
of
subbituminous
coal.
Being
highly
controlled
already,
it
is
also
a
relatively
costly
candidate
for
ACI
compared
to
other
plants
in
the
system.
Like
the
three
lignite
plants,
this
unit
already
meets
its
MACT
standard,
and
so
its
emissions
are
also
unchanged
under
the
MACT
option.

Response:

EPA
generally
agrees
with
the
commenter
that
cap
and
trade
is
not
expected
to
lead
to
hotspots.
EPA
has
done
extensive
power
sector,
air
quality,
deposition,
and
ecosystem
modeling.
See
the
preamble
for
the
rule
and
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
rather
than
providing
a
balanced
account
of
the
comments
EPA
has
received
to
date,
the
NODA
instead
appears
to
endorse
those
comments
that
call
for
weaker
regulations.
The
commenter
further
stated
that
this
aspect
of
the
NODA
is
most
clearly
apparent
in
EPA's
contrasting
treatment
of
the
comments
received
from
the
Center
for
Clean
Air
Policy
(
CCAP)
and
Cinergy
concerning
the
costs
of
complying
with
various
regulatory
approaches.
See
69
Fed.
Reg.
at
69,867­
69,868.
The
commenter
stated
that
according
to
the
NODA,
CCAP
and
Cinergy
reached
contrasting
conclusions
concerning
the
costs
and
burdens
associated
with
the
CAMR.
The
commenter
added
that
specifically,
CCAP
concluded
that
EPA
could
impose
even
stricter
requirements
with
relatively
modest
cost
implications,
while
Cinergy
concluded
that
EPA's
existing
proposal,
to
say
nothing
of
stricter
regulations,
was
already
"
unrealistic."
See
69
Fed.
Reg.
at
69,867­
69,868.
The
commenter
stated
that
rather
than
describing
those
contrasting
conclusions
in
a
balanced
manner,
EPA
instead
appears
to
endorse
Cinergy's
conclusion.
The
commenter
stated
that
the
NODA
states
that
9­
10
CCAP's
conclusion
is
CCAP's
"
opinion"
but
includes
no
such
disclaimer
for
Cinergy's
conclusion.
Compare
69
Fed.
Reg.
at
69,867
(
3d
Column)
with
69
Fed.
Reg.
at
69,868
(
3d
Column).
The
commenter
further
stated
that
EPA
also
appears
to
accept
at
face
value
Cinergy's
self­
serving
assertion
that
a
MACT
standard
of
0.88
lbs/
TBtu
is
"
stringent."
69
Fed.
Reg.
at
69,868
(
1st
Column).
According
to
the
commenter,
such
a
standard
is
approximately
four
times
weaker
than
the
standard
that
EPA
should
impose
absent
subcategorization
by
coal
rank.
See
Multistate
Comments
at
22
(
explaining
that
EPA
could
set
a
MACT
standard
of
0.2
lbs/
TBtu,
absent
subcategorization);
see
also
id.
at
A12­
13
(
discussing
the
MACT
standards
that
should
be
imposed
if
EPA
subcategorizes).
The
commenter
stated
that
in
these
circumstances,
and
in
light
of
its
treatment
of
CCAP's
conclusions,
the
NODA
should
have
clarified
that
it
is
simply
Cinergy's
"
opinion"
that
a
standard
of
0.88
lbs/
TBtu
is
stringent.
But,
the
commenter
stated,
the
NODA
contains
no
such
explanation
and
Cinergy's
own
comments
(
see
OAR­
2002­
0056­
4318)
provide
no
reason
to
accept
Cinergy's
assertion
as
fact.

The
commenter
stated
that
EPA
should
not
have
used
the
NODA
to
present
an
unbalanced
description
of
the
comments
received
in
response
to
the
proposed
CAMR.
In
addition,
the
commenter
also
objected
to
EPA's
failure
to
provide
sufficient
information
about
the
power
sector
modeling
runs
it
has
conducted.
The
commenter
noted
that
On
March
19,
2004,
Massachusetts
Attorney
General
Thomas
F.
Reilly
submitted
a
public
record
request
to
EPA
regarding
its
Integrated
Planning
Model
(
IPM)
runs.
The
commenter
further
noted
that
in
response,
EPA
has
withheld
hundreds
of
documents
alleging
that
they
fall
within
Exemption
5
of
the
Freedom
of
Information
Act.
See
Exhibit
B
(
Letter
from
Byron
R.
Brown,
Assistant
General
Counsel,
EPA,
to
James
R.
Milkey
dated
December
9,
2004).
(
See
OAR­
2002­
0056­
5460.)
The
commenter
stated
that,
significantly,
several
of
the
documents
EPA
is
withholding
appear
to
contain
factual
information
bearing
directly
on
the
NODA's
discussion
of
power
sector
modeling
(
and
may
be
relevant
to
the
CAMR
for
other
reasons
as
well).
The
commenter
further
stated
that
EPA's
failure
to
make
those
documents
available
to
the
public
in
the
CAMR
docket
is
problematic
for
the
following
reasons:
First,
if
EPA
has
ignored
the
documents,
it
may
have
acted
in
an
arbitrary
and
capricious
manner
in
developing
the
CAMR.
The
commenter
stated
that,
alternatively,
if
it
has
considered
the
documents,
its
failure
to
make
the
documents
available
for
public
review
and
comment
may
violate
both
the
Clean
Air
Act
and
the
Administrative
Procedure
Act.
See
42
U.
S.
C.
§
7607(
d)(
3)
("
All
data,
information,
and
documents.
.
.
on
which
the
proposed
rule
relies
shall
be
included
in
the
docket.
.
.");
Portland
Cement
Ass'n
v.
Ruckelshaus,
486
F.
2d
375,
393
(
D.
C.
Cir.
1973)
("
It
is
not
consonant
with
the
purpose
of
a
rule­
making
proceeding
to
promulgate
rules
on
the
basis
of
inadequate
data,
or
on
data
that,
[
to
a]
critical
degree,
is
known
only
to
the
agency.")
The
commenter
stated
that,
accordingly,
EPA
should
make
the
documents
available
in
the
CAMR
docket
and
should
explain
how,
if
at
all,
it
has
used
the
documents
in
developing
and
proposing
the
CAMR.

Response:

EPA's
presentation
of
summaries
of
the
commenters
data
was
not
meant
as
an
endorsement
to
any
of
the
commenters
data.
EPA
will
address
the
commenters
concerns
related
to
document
availability
in
the
FOIA
process.

Comment:
9­
11
The
commenter
(
OAR­
2002­
0056­
5460)
noted
that
EPA
contends
that
power
sector
modeling
is
relevant
to
its
obligation
under
Section
112
of
the
Clean
Air
Act
to
set
beyond­
the­
floor
standards
based
on
an
analysis
of
cost,
non­
air
quality
health
and
environmental
impacts
and
energy
impacts.
See
69
FR
at
69,866
(
2nd
column).
But,
the
commenter
stated,
the
NODA
does
not
adequately
explain
how
power
sector
modeling
is
relevant
to
assessing
non­
air
quality
health
impacts,
non­
air
quality
environmental
impacts
or
energy
impacts.
The
commenter
further
stated
that,
indeed,
the
NODA's
focus
on
comments
concerning
the
alleged
cost
of
certain
control
measures
creates
the
impression
that
power
sector
modeling
is
relevant
solely
to
cost.
Therefore,
the
commenter
reiterated
that
EPA
is
required
to
also
consider
non­
air
quality
health
and
environmental
impacts
in
setting
beyond­
the­
floor
standards
pursuant
to
Section
112.

The
commenter
stated
that
it
also
bears
emphasis
that
industry
commenters
have
an
incentive
to
overstate
the
costs
of
complying
with
environmental
regulations.
The
commenter
further
stated
that,
indeed,
various
studies
have
suggested
that
the
costs
of
complying
with
environmental
regulations
are
usually
less
than
what
industry
commenters
estimated
in
advance.
The
commenter
added
that,
accordingly,
EPA
should
look
skeptically
upon
industry
cost
estimates.
The
commenter
stated
that
one
reason
industry
cost
estimates
may
be
too
high
is
the
failure
to
anticipate
technological
innovations
that
regulations
will
inspire.
For
a
fuller
discussion
of
this
issue,
the
commenter
referred
EPA
to
the
CAMR
comments
of
the
Northeast
States
for
Coordinated
Air
Use
Management
(
NESCAUM),
OAR­
2002­
0056­
2888,
and
to
NESCAUM's
September
2000
report
entitled
Environmental
Regulation
and
Technology
Innovation:
Controlling
Mercury
Emissions
from
Coal­
Fired
Boilers,
a
copy
of
which
is
attached
as
Exhibit
D
(
See
OAR­
2002­
0056­
5460).

Response:

EPA's
approach
for
the
final
rulemaking
is
to
establish
Hg
reductions
under
section
111
cap
through
a
cap­
and­
trade
mechanism.
EPA
agrees
with
the
commenter
that
technology
innovation
is
likely
to
reduce
future
control
costs.
To
that
end,
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
rulemaking.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
none
of
the
information
that
EPA
has
requested
is
relevant
to
determining
the
proper
MACT
floor
under
Section
112
of
the
Clean
Air
Act
 
a
fact
that
EPA
itself
appears
to
recognize.
See
69
Fed.
Reg.
69,864­
69,866
(
2nd
column)
(
explaining
why
EPA
believes
the
information
it
seeks
concerning
power
sector
modeling
and
Hg
speciation
is
relevant),
id.
at
69,872
(
2nd
Column)
(
same
for
the
information
EPA
seeks
concerning
its
proposed
revised
benefits
assessment
methodology).
The
commenter
stated
that,
thus,
the
NODA
does
not
address
one
of
the
most
fundamental
defects
in
the
CAMR.
The
commenter
further
stated
that,
indeed,
the
NODA
does
not
even
mention
the
MACT
floor
issue.
The
commenter
stated
that
by
omitting
mention
of
that
issue,
EPA
has
presented
an
incomplete
account
of
the
issues
raised
in
the
CAMR
comments.
The
commenter
also
stated
that
in
addition,
until
EPA
calculates
a
proper
MACT
floor
pursuant
to
Section
112,
both
its
prior
analysis
and
its
proposed
new
analysis
of
the
benefits
of
the
CAMR
will
remain
logically,
factually
and
legally
flawed.
9­
12
The
commenter
stated
that
the
NODA
also
fails
to
address
the
legal
problems
inherent
in
EPA's
alternative
Section
111
regulatory
proposal.
The
commenter
further
stated
that,
instead,
it
focuses
on
a
variety
of
technical
issues
that
are
at
best
a
distraction
from
the
central
problems
with
the
CAMR.
According
to
the
commenter,
for
example,
the
NODA
contains
an
extensive
discussion
of
comments
EPA
has
received
concerning
the
relationship
between
the
CAMR
and
EPA's
proposed
Clean
Air
Interstate
Rule
(
CAIR).
See
69
Fed.
Reg.
at
69,868­
69,871.
But,
according
to
the
commenter,
the
EPA
is
required
to
develop
lawful
regulations
pursuant
to
Section
112
of
the
Clean
Air
Act
regardless
of
what
its
models,
or
any
commenters'
models,
reveal
about
the
consequences
of
CAIR.
The
commenter
added
that,
equally
important,
EPA
recently
announced
that
it
is
delaying
the
implementation
of
the
CAIR
indefinitely.
See
Exhibit
A
(
D.
Samuelsohn,
"
Bush
Holds
CAIR
Release
As
Congress
Shows
Interest
in
Clear
Skies,"
Greenwire,
Dec.
13,
2004)
(
also
available
at
http://
www.
eenews.
net/
Greenwire/
Backissues/
121304/
121304gw.
htm
).
The
commenter
stated
that,
accordingly,
EPA
should
not
base
either
its
Section
112
or
Section
111
approach
on
estimates
of
what
CAIR
might
or
might
not
accomplish.

Response:

EPA
issued
the
NODA
to
take
further
comment
on
commenter's
analyses
submitted
to
docket
after
proposal
and
their
impact
on
final
rulemaking
analyses.
EPA
took
comment
on
its
regulatory
approach
in
the
NPR
and
SNPR.

1.
In
some
analyses,
EEI
assumed
a
2.5
percent
annual
improvement
in
variable
operating
costs
for
ACI.
Is
it
appropriate
for
an
economic
forecast
to
assume
an
improvement
in
costs
over
time
and
if
so,
what
level
of
improvement
in
costs
should
be
assumed?

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
believes
that
EPA's
modeling
effort
was
deficient
in
that
it
assumes
that
technology
will
not
advance
and
that
the
costs
will
not
decrease
and
that
as
other
EPA
regulatory
efforts
have
demonstrated,
advances
in
control
technology
for
Hg
are
occurring
at
great
speed
and
costs
will
likely
continue
to
decline.
Additionally,
the
model
did
not
consider
sufficient
control
options,
including
precombustion
controls,
fabric
filters
and
improvements
in
the
functioning
of
existing
controls.
These
options
would
provide
a
range
of
reductions,
which
were
not
accounted
for
in
the
model.

The
commenter's
concerns
about
the
deficiencies
of
some
of
the
modeling
in
the
NODA
and
the
agency's
own
effort
are
among
the
reasons
they
believed
EPA
should
have
conducted
additional
modeling
of
more
effective
MACT
scenarios,
with
thorough
discussions
with
the
stakeholders
about
realistic
and
up­
to­
date
inputs
and
assumptions.

Response:

EPA
has
conducted
modeling
analysis
for
the
final
rule
under
section
111.
EPA's
IPM
model,
due
to
model
run
time
constraints,
has
to
limit
the
number
of
control
retrofit
options
available.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
9­
13
costs
of
the
final
rulemaking.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5446)
stated
that,
typically,
it
is
reasonable
to
assume
that
the
costs
associated
of
with
technology
will
fall
as
the
technology
becomes
more
widely
deployed
and
operational
experience
is
obtained.
However,
it
is
premature
to
assume
that
dedicated
Hg
control
technology
will
follow
this
trend
in
the
years
immediately
following
its
introduction.
In
this
case,
the
introduction
of
new
regulation
is
likely
to
dramatically
increase
demand
for
the
dedicated
controls
and
sorbents
required
and
it
is
likely
that
in
the
initial
period
supply
will
be
not
adequate
for
this
new
level
of
demand.
Scarcity
value
will
result
in
a
corresponding
increase
in
price.

Given
the
time
value
of
money
these
near
term
impacts
may
have
a
significant
impact
on
the
net
present
cost
of
the
proposed
regulations.
If
the
EPA
decides
it
needs
to
more
accurately
represent
the
evolution
of
cost
with
time
it
must
also
capture
the
impact
of
potentially
dramatic
changes
in
the
balance
of
supply
and
demand
and
the
corresponding
price
impacts
for
both
control
technologies
and
sorbents
such
as
activated
carbon.
Absent
a
detailed
assessment
of
supply
and
demand
the
EPA
should
not
assume
that
prices
decline.

Response:

EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
rulemaking.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
Given
that
the
first
phase
cap
is
set
at
38
tons,
the
Hg
co­
benefit
reductions
expected
under
CAIR,
EPA
does
not
anticipate
demand
impacts
for
control
technologies
and
sorbents.
EPA's
analysis
of
past
programs,
like
the
NOx
SIP
call,
indicate
the
markets
respond
to
the
demand
for
materials.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
October
2002,
in
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5488)
stated
that
in
the
NODA,
EPA
invites
comment
on
results
from
several
alternative
analyses
submitted
in
comments
on
its
proposed
Hg
rule
and
additionally
invites
"
updated
information
on
issues
that
may
be
relevant
to
assessing
the
assumptions
employed
in
our
power
sector
modeling."
As
a
preliminary
matter,
it
should
go
without
saying
that
regulatory
analyses
performed
by
stakeholders
are
no
substitute
for
the
exercise
of
independent
judgment
by
EPA.
While
EPA
should
consider
comments
submitted
by
stakeholders,
it
is
a
bedrock
principle
of
administrative
law
that
the
agency
must
independently
exercise
its
expertise
to
establish
the
grounds
for
its
decisions.
The
commenter
addressed
their
comments
primarily
to
EPA's
analyses,
rather
than
those
of
the
outside
groups
that
are
called
out
in
the
NODA.

EPA's
power
sector
modeling
is
fundamentally
flawed
because
it
ignores
recent
advances
in
control
technology
that
have
already
occurred
and
moreover
assumes
that
no
advances
will
occur
over
the
time
frame
of
the
regulations.
The
modeling
is
also
overly
restrictive
in
the
control
9­
14
options
it
allows.

In
projecting
control
costs
over
the
time
frame
of
this
proposal,
EPA
must
incorporate
benefits
of
technological
advances
in
control
cost
projections,
especially
given
the
fact
that
Hg
control
technology
is
already
advancing
very
rapidly.
In
fact,
OMB
guidelines
require
that
cost
estimates
used
in
agency
rulemakings
reflect
"
credible
changes
in
technology
over
time."
As
described
above,
major
advances
in
control
technology
accompanied
by
dramatic
reductions
in
control
costs
have
been
demonstrated
over
the
past
year,
rendering
obsolete
some
of
the
most
critical
assumptions
in
EPA's
power
sector
modeling.
EPA
is
fully
aware
of
many
of
these
advances.
Consequently,
EPA's
assumption
that
control
costs
will
not
change
over
the
next
decade
is
clearly
untenable.
EPA
must
adjust
the
starting
point
for
its
control
cost
estimates
to
reflect
current
reality,
and
further
must
incorporate
a
reasonable
rate
of
improvement
in
its
forecasts.
Because
empirical
estimates
of
the
rate
of
improvement
in
control
costs
over
time
are
sparse,
EPA
should
begin
with
reasonable
base
case
estimates
of
improvement
rates
and
conduct
sensitivity
analyses
to
examine
the
importance
of
this
parameter.
Based
on
experience
with
similar
control
programs
and
the
advances
in
Hg
control
technology
that
have
already
occurred,
a
default
assumption
of
no
improvement
is
clearly
unreasonable.

Modeling
performed
for
the
Clean
Air
Task
Force
(
CATF)
and
other
environmental
groups
demonstrates
that
much
more
stringent
MACT
emissions
standards
can
be
cost­
effectively
achieved
than
those
proposed
by
EPA,
even
utilizing
EPA's
misguided
scheme
of
setting
disparate
standards
by
coal
rank.
Furthermore,
even
with
a
cursory
assessment
of
benefits,
the
CATF
analysis
shows
that
the
benefits
of
the
more
stringent
standards
they
examined
would
outweigh
the
costs.
EPA
should
take
this
comment
into
account
in
revising
its
own
power
sector
modeling,
by
exploring
alternative
levels
of
stringency
for
the
MACT
standards.
EPA
must
go
beyond
the
CATF
analysis,
however,
and
consider
stringent
standards
for
all
ranks
of
coal
and
coal
blends,
for
new
and
existing
units.

Response:

EPA
has
conducted
modeling
analysis
for
the
final
rule
under
section
111.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
stated
that
technological
advances
anticipated
from
specific
on­
going
research
programs
could
reduce
the
costs
of
the
proposed
Cap
and
Trade
rule
by
up
to
30
percent,
but
would
provide
no
significant
reduction
in
the
costs
of
the
alternative
MACT
approach.

Response:

EPA
has
conducted
modeling
analysis
for
the
final
rule
under
section
111.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
9­
15
Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
stated
that
EPA
requested
comment
on
whether
the
economic
model
should
account
for
improvement
in
technology
costs
over
time.
The
commenter
believed
that
it
should.
The
commenter
noted
in
their
comments
on
the
proposed
rule,
the
IPM
assumes
that
control
technologies
are
static,
leading
to
an
overestimate
of
control
costs.
In
particular
EPA
should
account
for
the
expected
decrease
in
the
cost
of
activated
carbon,
as
this
expense
comprises
the
bulk
of
variable
operating
costs.
EPA
has
previously
stated
that
the
cost
of
activated
carbon
is
expected
to
decrease
by
40
percent
with
widespread
implementation
of
the
technology.
In
addition,
the
IPM
should
be
adjusted
to
account
for
the
lower
quantity
of
halogentated
carbons
that
would
be
needed
and
the
lower
quantity
of
solid
waste
generated.
Also,
because
the
brominated
carbons
do
not
affect
the
quality
of
fly
ash
for
use
in
concrete,
EPA
must
revise
the
assumptions
in
the
IPM
related
to
loss
of
revenue
from
flyash
sales.

Response:

EPA
has
conducted
modeling
analysis
for
the
final
rule
under
section
111.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
of
a
second
ACI
option
using
advanced
sorbents.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
it
was
inappropriate
for
an
economic
forecast
to
assume
a
decrease
in
variable
costs
over
the
foreseeable
future
for
Hg
controls.
With
respect
to
ACI,
activated
carbon
reagent
now
costs
$
0.50/
lb
and
is
unlikely
to
decrease
to
any
significant
degree.
The
business
of
manufacturing
this
reagent
is
already
mature
and
this
is
not
a
situation
where
a
product
with
a
limited
production
volume
and
history
is
likely
to
experience
decreases
in
unit
cost.
Indeed,
activated
carbon
already
has
significant
existing
demand
and
the
implementation
of
ACI
at
power
plants
is
more
likely
to
increase
its
unit
cost.
EPA
estimated
in
2002
that
demand
for
both
activated
and
granular
carbon
to
be
227,000
tons
in
2004,
in
comparison
to
a
manufacturing
capacity
of
233,000
tons
annually.
EPA
also
estimated
that
about
70
GW
of
coal­
fired
capacity
would
retrofit
ACI,
requiring
an
additional
220,000
tons
of
activated
carbon.
Doubling
the
demand
from
already
high
production
rates
could
well
increase
and
not
decrease
the
unit
cost
of
activated
carbon.
For
this
reason,
an
assumption
in
EPA's
model
that
activated
carbon
costs
will
remain
the
same
over
time
may
underestimate
the
actual
costs.

Response:

EPA
has
conducted
modeling
analysis
for
the
final
rule
under
section
111.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
advanced
sorbents,
leading
to
lower
capital
costs
not
variable
operating
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
With
regard
to
demand
for
activated
carbon,
EPA
notes
that
the
report
cited
by
the
commenter
indicates
that
markets
respond
to
the
9­
16
demand
for
materials,
much
like
under
the
NOx
SIP
call
supply
for
catalyst
increased
with
demand.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
October
2002,
in
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
in
its
June
2004
submission
(
see
OAR­
2002­
0056­
2929),
Charles
River
Associates
provided
results
for
a
set
of
five
different
possible
rates
of
technological
change.
These
included
a
2.5
percent
and
4
percent
p.
a.
rate
of
reduction
in
our
base
assumptions
for
variable
O
and
M
costs
on
the
sorbent­
based
control
technology
(
referred
to
generically
as
ACI
here),
and
a
1
percent
and
2
percent
p.
a.
rate
of
reduction
in
our
base
assumptions
for
capital
costs,
and
variable
and
fixed
O&
M.
The
first
two
cases
were
intended
to
reflect
future
reductions
in
the
costs
of
sorbent
and/
or
injection
rates
(
lb/
Macf)
needed
to
achieve
each
level
of
percentage
removal
through
an
advanced
sorbent
technology.
The
second
two
cases
reflected
future
reductions
also
in
the
cost
of
the
baghouse
technology
that
is
assumed
necessary
in
our
base
assumptions
in
order
to
achieve
the
lowest
$/
ton
removed
for
percentage
reductions
in
the
60­
90
percent
range
(
i.
e.,
TOXECON
TM).
This
could
imply
refinements
in
design
or
materials
of
the
baghouse,
or
possible
development
of
more
costeffective
alternatives
that
would
still
entail
initial
costs,
but
for
some
less
costly
alternative
to
a
COHPAC
baghouse
that
still
reduces
the
sorbent
injection
rates
than
are
currently
necessary
to
achieve
high
percentage
reductions
in
front
of
an
ESP
only.
Finally,
a
0
percent
rate
of
improvement
was
also
considered.

The
commenter
suggested
that
these
scenarios
presented
a
range
of
possibilities
for
exploring
how
much
the
prospect
of
technological
improvement
might
affect
results.
It
is
almost
certain
that
some
degree
of
cost
reduction
will
occur
if
time
is
permitted,
and
that
the
likely
reductions
will
be
increasing
with
time.
Charles
River
Associates
did
not
suggest
that
anyone
of
these
is
a
most
likely
case,
but
the
range
of
prospects
is
quite
broad,
and
it
provides
a
good
test
bed
for
understanding
the
impacts
of
technical
change
on
costs
of
a
Hg
cap­
and­
trade
policy
that
provides
for
a
gradual
phase­
in
of
control
installations.

In
its
June
submission
(
see
OAR­
2002­
0056­
2929),
the
commenter
reported
that
the
marginal
costs
of
controls,
especially
in
later
years,
were
quite
sensitive
to
any
rate
of
improvement,
and
that
estimated
total
costs
of
controls
also
fell.
These
are
not
surprising
results,
and
the
main
interest
was
the
degree
to
which
allowance
prices
might
be
keep
below
levels
such
as
that
set
by
EPA's
proposal
as
a
"
safety
valve"
price
of
$
31,500
(
1999$).
With
any
but
the
worst
case
assumption
of
zero
technological
improvement,
marginal
costs
of
control
were
projected
to
remain
below
that
price
through
2020,
even
when
emissions
achieve
the
15
ton
level.
Table
8
reproduces
the
allowance
price
sensitivities
that
the
commenter
reported
in
the
June
submission.
9­
17
Table
8.
Projected
Mercury
Allowance
Prices
Under
Alternative
Assumptions
of
Rates
of
Improvement
in
Hg
Control
Technology
($/
lb
Hg,
in
1999$;
2020
marks
start
of
terminal
period
in
model
used)

Year
Annual
Rate
of
Technological
Improvement
on
Activated
Carbon
Infection
Control
Methods
0%
1.5%
2.5%
2.5%
4.0%

Capital
and
O&
M
Capital
and
O&
M
Variable
O&
M
only
Variable
O&
M
only
2010
$
22,108
$
21,850
$
22,345
$
20,854
$
20,090
2012
$
21,654
$
19,623
$
17,904
$
18,727
$
17,420
2015
$
25,826
$
23,404
$
21,353
$
22,335
$
20,775
2018
$
30,824
$
27,933
$
25,485
$
26,657
$
24,796
2020
$
37,285
$
28,495
$
23,611
$
32,536
$
30,951
The
glide
paths
of
all
five
of
the
cases
considered
in
our
June
2004
submission
are
not
different
enough
to
merit
a
graph.
They
all
attained
Hg
emissions
of
15
tons
by
2020.
A
conclusion
that
the
commenter
can
draw
from
this
set
of
runs
is
that
technological
change
is
more
likely
to
affect
costs,
and
particularly
marginal
costs,
of
meeting
a
cap,
but
that
it
does
not
much
alter
the
glide
path
between
Phase
I
and
Phase
II
of
a
policy.

Response:

EPA
agrees
with
the
commenter
that
Hg
technology
costs
are
likely
to
improve
over
time.
EPA
has
conducted
modeling
analysis
for
the
final
rule
under
section
111.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

2.
The
IPM
has
limited
Hg
control
retrofit
options.
Currently,
it
assumes
that
Hg
reductions
are
achieved
only
through
SCR
and
FGD
or
ACI
(
with
or
without
fabric
filter).
Should
other
control
options
be
considered(
e.
g.,
retrofit
of
fabric
filters
and
electrostatic
precipitators,
pre­
combustion
controls,
and
optimization
of
SO2
or
NOx
controls?

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
states
that
one
of
their
biggest
concerns
regarding
the
NODA
is
that
it
focuses
undue
attention
on
the
IPM
modeling
that
commenters
submitted
and
their
related
inputs,
assumptions,
results
and,
particularly,
the
cost
of
control,
control
efficiency
and
the
technical
feasibility
of
various
control
options.
The
discussions
about
cost,
especially,
distract
from
the
most
important
point
of
all:
the
Clean
Air
Act
clearly
calls
for
emissions
of
hazardous
air
pollution
from
electric
utilities
to
be
regulated
under
Section
112,
which
requires
EPA
to
establish
a
MACT
standard
that
reflects
at
least
"
the
average
emission
limitation
achieved
by
the
best
performing
12
percent
of
the
existing
sources"
or
"
the
emission
9­
18
control
that
is
achieved
in
practice
by
the
best
controlled
similar
source."
Consideration
of
cost
is
inappropriate
during
the
determination
of
the
MACT
floor
and
should
be
used
only
in
calculations
of
MACT
levels
that
are
beyond
the
floor.
Therefore,
the
cost
calculations
articulated
in
the
NODA
should
not
be
part
of
the
determination
of
the
MACT
floor
for
electric
utilities.

To
the
extent
that
some
of
the
modeling
is
useful
in
considering
MACT
options
beyond
the
floor,
however,
the
commenter
offers
some
general
observations
about
what
is
contained
in
the
NODA.

The
commenter
does
not
believe
the
information
contained
in
the
NODA
portrays
the
tremendous
advancements
in
control
technology
that
have
come
about
recently,
even
since
the
proposal
was
issued.
As
up­
to­
date
data
show,
controls
that
can
result
in
significant,
MACT­
level
reductions
are
not
only
technically
feasible,
but
are
also
cost­
effective
and
commercially
available.
These
controls
include
low
NO
x
burners,
activated
carbon
injection
(
ACI)
with
various
sorbents,
selective
catalytic
reduction,
enhanced
wet
scrubbers,
fabric
filters
and
acid
gas
controls
for
reducing
Hg
emissions.
These
are
already
available
for
installation
on
coal­
fired
utility
boilers
for
all
types
of
coal.

Unfortunately,
several
of
the
modeling
results
summarized
in
the
NODA
do
not
account
for
recent
technological
developments
(
e.
g.,
halogenated
sorbents)
or
adequately
consider
control
options
(
e.
g.,
low
NO
x
burners
or
fabric
filters)
in
their
assumptions
and
calculations.
As
a
result,
their
conclusions
do
not
reflect
what
is
currently
possible
and
skew
cost
and
emission
reduction
estimates.

The
ACI­
type
of
control,
which
is
currently
commercially
available,
has
low
capital
cost
and
minimal
maintenance
requirements.
There
have
been
recent
improvements
in
sorbents
that
result
in
significant
cost
reductions
and
increased
control
efficiency.
ACI
can
reduce
Hg
emissions
by
over
90
percent,
can
be
installed
quickly
and
is
effective
on
both
bituminous
and
subbituminous
coals.

Response:

EPA
is
finalizing
a
rule
under
Section
111
and
has
conducted
modeling
analysis
for
the
final
rule.
EPA's
IPM
model,
due
to
model
run
time
constraints,
has
to
limit
the
number
of
control
retrofit
options
available.
EPA
agrees
with
the
commenter
that
Hg
technology
costs
are
likely
to
improve
over
time.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
whitepaper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5332)
noted
that
EPA
indicates
in
the
NODA
that
"
due
to
model
size
considerations,
limited
knowledge
on
achievable
levels
of
Hg
control,
and
limited
9­
19
know
ledge
on
assessing
the
full
impact
of
the
Hg
speciation
profile
on
control,"
the
IPM
modeling
it
has
performed
assumes
Hg
reductions
are
achievable
only
through
use
of
SCR
and
wet
FGD,
or
ACI.
The
commenter
understands
that
model
size
considerations
impose
limitations
on
the
number
of
control
options
that
can
be
analyzed.
However,
since
at
least
some
stakeholders
are
questioning
whether
ACI
should
be
considered
to
be
a
commercially
available
technology
prior
to
2010
(
see
discussion
below),
limiting
the
modeling
to
these
two
control
options
may
not
provide
a
representative
range
of
achievable
Hg
emissions
reductions
and
control
costs.

The
commenter
suggested
that
the
model
should
include,
at
a
minimum,
retrofitting
plants
with
fabric
filters
as
an
available
control
option.
According
to
EPA's
own
analysis
of
its
extensive
ICR
database,
fabric
filters
are
capable
of
achieving
an
average
of
90
percent
Hg
removal
on
units
burning
bituminous
coal
and
over
70
percent
removal
on
units
burning
subbituminous
coal.
Moreover,
no
one
would
question
the
commercial
availability
of
this
technology.

A
host
of
other
options
are
still
undergoing
testing
and
only
preliminary
performance
and
cost
data
are
available.
These
include:
(
1)
optimization
of
existing
SO
2
and
NOx
controls;
(
2)
pre­
combustion
controls
(
e.
g.,
fuel
cleaning
and
fuel
blending);
(
3)
alternative
sorbents
(
e.
g.,
halogenated
activated
carbon,
non­
carbon
based
sorbents);
(
4)
back­
end
additives
and
oxidation
catalysts;
and
(
5)
multi­
pollutant
technologies.
In
light
of
the
ongoing
testing
of
these
control
options
and
considering
model
size
limitations,
the
commenter
supports
the
decision
not
to
include
these
options
in
the
modeling
analyses.

Response:

EPA's
IPM
model,
due
to
model
run
time
constraints,
has
to
limit
the
number
of
control
retrofit
options
available.
EPA
agrees
with
the
commenter
that
Hg
technology
costs
are
likely
to
improve
over
time.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option,
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5484)
stated
that
in
the
NODA,
EPA
asks
for
updated
information
on
Hg
control
options
such
as
activated
carbon
injection
(
with
and
without
fabric
filters),
including
the
time
line
for
commercialization,
cost,
balance
of
plant
impacts,
and
performance.
To
that
end,
the
commenter
commissioned
RMB
Consulting
and
Research,
Inc.,
to
develop
the
report
entitled,
"
The
Potential
Effect
of
Activated
Carbon
Injection
on
Coal­
Fired
Power
Plant
Operation."
This
report
details
the
operational
difficulties
associated
with
activated
carbon
injection,
both
with
and
without
a
fabric
filter.
It
concludes
that
these
balance­
of­
plant
impacts
will
limit
the
applicability
of
activated
carbon
injection,
especially
into
existing
electrostatic
precipitators
and
bag
houses.

Response:
9­
20
The
Agency's
position
on
the
state
of
Hg
technology,
including
ACI,
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5559)
stated
that
EPA
should
consider
adjusting
the
Hg
control
levels
for
several
technologies
in
the
IPM
model
to
reflect
optimal
control.
For
example,
fabric
filters
are
effective
at
controlling
all
forms
of
Hg
species.
However,
decreasing
flue
gas
temperatures
and
increasing
exhaust
gas
contact
time
with
the
filter
cake
can
further
enhance
elemental
Hg
control.
Therefore,
the
control
levels
assumed
in
the
IPM
model
for
fabric
filters
should
be
higher
than
the
72
percent
and
90
percent
average
control
levels
determined
by
the
1999
ICR
data
respectively
for
sub
bituminous
and
bituminous
fired
units.

The
IPM
control
options
need
to
be
expanded
to
include
dedicated
and
integrated
Hg
control
technologies.
At
the
minimum,
a
fabric
filter
operating
at
optimal
Hg
control
levels
should
be
an
available
option
for
new
and
existing
utility
units
as
a
dedicated
control
technology.
Integrated
Hg
control
technologies
that
should
be
added
include
the
addition
of
sorbent
injection
and
oxidizing
technologies
in
conjunction
with
new
and
existing
control
systems.

The
IPM
model
should
also
be
improved
by
inclusion
of
recently
tested
control
options.
One
prime
example
is
the
development
of
brominated
activated
carbon
by
Sorbent
Technologies.
This
sorbent
has
demonstrated
very
high
Hg
reductions
at
a
cost
lower
than
activated
carbon
regardless
of
Hg
speciation
or
control
system.
This
sorbent
is
also
available
in
a
form
compatible
with
cement
fly
ash
re­
use.
The
availability
of
this
sorbent
and
other
injection
materials
with
similar
outcomes
such
as
sodium
tetrasulfide
and
ADVACATE
multi­
pollutant
sorbent
support
inclusion
into
the
IPM
model.
Similarly,
EPA
needs
to
incorporate
advancements
in
oxidation
catalysts
and
agents
into
the
IPM
model.

Response:

EPA's
IPM
model,
due
to
model
run
time
constraints,
has
to
limit
the
number
of
control
retrofit
options
available.
The
ACI
option
in
EPA'
s
IPM
includes
the
addition
of
a
pulse­
jet
fabric
filter
to
achieve
90%
control.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5591)
stated
that
injecting
a
sorbent
such
as
powdered
activated
carbon,
bromine,
polysulfides,
or
other
sorbent
into
the
flue
gas
represents
a
relatively
9­
21
simple
approach
to
controlling
Hg
emissions
from
coal­
fired
boilers.
The
gas­
phase
Hg
in
the
flue
gas
contacts
the
sorbent
and
attaches
to
its
surface.
The
sorbent
with
the
Hg
attached
is
then
collected
by
the
existing
particle
control
device,
either
an
electrostatic
precipitator
(
ESP)
or
fabric
filter
(
FF).

The
air
pollution
control
industry
already
has
considerable
experience
with
the
implementation
of
Hg
controls
for
other
industrial
sectors.
Sorbent
injection
has
been
commercially
proven
to
augment
the
removal
of
Hg
in
waste­
to­
energy
plants.
Experience
controlling
Hg
emissions
has
been
gained
in
more
than
60
U.
S.
and
120
international
waste­
to­
energy
plants
that
burn
municipal
or
industrial
waste
or
sewage
sludge.
For
the
past
two
decades,
sorbent
injection
upstream
of
a
baghouse
has
been
successfully
used
for
removing
Hg
from
flue
gases
from
these
facilities.
Other
reagents
used
include
activated
carbon,
lignite
coke,
sulfur
containing
chemicals,
or
combinations
of
these
compounds.
The
Hg
control
experience
gained
from
the
municipal
and
industrial
waste
combustors
demonstrates
that
the
air
pollution
control
industry
has
been
able
to
control
Hg
in
the
past
and
is
able
to
apply
their
expertise
to
the
electric
power
sector.

Powerspan
Corporation's
Electro­
Catalytic
Oxidation
(
ECO)
is
an
integrated
multipollutant
control
technology
that
achieves
major
reductions
in
emissions
of
nitrogen
oxides
(
NO
x),
sulfur
dioxide
(
SO
2),
fine
particulate
matter
(
PM
2.5),
and
Hg.
The
technology
also
reduces
emissions
of
other
air
toxic
compounds
and
acid
gases
such
as
arsenic,
lead,
and
hydrochloric
acid
(
HCl).
ECO
produces
a
commercial
fertilizer
co­
product,
reducing
operating
costs
and
avoiding
landfill
disposal
of
waste.

ECO
is
situated
downstream
of
a
power
plant's
existing
electrostatic
precipitator
(
ESP)
or
fabric
filter.
The
system
consists
of
three
gas­
processing
steps,
including
a
barrier
discharge
reactor,
an
ammonia­
based
wet
scrubber,
and
a
wet
ESP.
The
barrier
discharge
reactor
oxidizes
SO
2,
NO
x,
and
Hg;
the
ammonia
scrubber
removes
SO
2,
NO
2,
and
oxidized
Hg
creating
an
ammonium
sulfate
nitrate
solution;
and
the
wet
ESP
captures
acid
aerosols,
fine
particulate
matter,
and
oxidized
Hg.

Liquid
effluent
produced
by
the
scrubber
contains
dissolved
ammonium
sulfate
nitrate
(
ASN)
salts,
along
with
Hg
and
captured
particulate
matter.
The
ASN
solution
is
sent
to
a
co­
product
recovery
system,
which
includes
filtration
to
remove
ash
and
a
sulfur
impregnated
activated
carbon
adsorption
bed,
which
removes
Hg
from
the
effluent
stream.
The
Hg
and
spent
activated
carbon
are
disposed
of
as
hazardous
waste.
The
treated
co­
product
stream,
free
of
Hg
and
ash,
can
be
used
directly
in
liquid
form
or
processed
to
form
ammonium
sulfate
nitrate
fertilizer
in
crystalline
or
granular
form.

KFx,
Inc.
has
a
patented
and
proven
pre­
combustion
technology
that
transforms
low­
cost,
low­
grade
western
coal
(
e.
g.,
lignite
or
subbituminous)
into
a
clean,
affordable,
efficient
energy
source,
called
K­
Fuel.
K­
Fuel
pre­
combustion
technology
applies
heat
and
pressure
to
boost
the
heat
value
of
subbituminous
coal
and
lignite
by
30­
55
percent,
from
approximately
8,000­
8,800
Btu/
lb
to
11,00011,500
Btu/
lb,
optimizing
combustion
in
a
manner
that
produces
more
generation
output
per
ton
of
coal
while
lowering
emissions.
Moisture
in
the
coal
can
be
reduced
by
as
much
as
80
percent
from
approximately
30
percent
in
the
feedstock
to
seven
percent
in
K­
Fuel.
9­
22
Similar
to
post
combustion
SO
2,
NO
x,
and
PM
controls,
Hg
emission
reductions
from
the
K­
Fuel
technology
are
a
co­
benefit
of
the
pre­
combustion
process.
K­
Fuel
provides
a
pre­
combustion
Hg
removal
solution,
reducing
Hg
content
by
up
to
70
percent
or
more.
In
addition
to
Hg
reductions,
K­
Fuel
also
reduces
emissions
of
SO
2
and
NO
x.

Response:

EPA
agrees
with
the
commenter
that
there
are
likely
many
technology
advances
in
the
control
of
Hg.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
stated
that
it
recommends
modification
of
the
IPM
modeling
with
respect
to
using
additional
control
options.
Additional
control
options
(
e.
g.,
retrofit
of
fabric
filters
and
electrostatic
precipitators,
brominated
activated
carbon
injection)
should
be
considered
in
EPA's
power
sector
modeling.
This
commenter
believes
that
the
current
approach,
which
only
takes
into
account
selective
catalytic
reduction
(
SCR),
flue
gas
desulfurization
(
FGD),
and
activated
carbon
injection
(
ACI),
underestimates
the
benefits
achieved
by
other
technologies.
Consideration
of
additional
controls
in
the
modeling
would
yield
more
realistic
results.

Response:

EPA
agrees
with
the
commenter
that
there
are
likely
many
technology
advances
in
the
control
of
Hg.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5446)
stated
that
EPA
should
consider
the
addition
of
other
control
options
such
as
fabric
filters
and
ESP's
where
the
performance
of
these
technologies
can
be
sufficiently
well
characterized
for
the
purpose
of
a
regulatory
decision.

EPA
should
not
model
control
options
that
have
not
been
reasonably
demonstrated
at
an
appropriate
scale
and
over
the
range
of
operating
conditions
that
a
real
plant
will
encounter.
Short­
term
field
tests
or
demonstration
projects
are
an
inadequate
basis
for
regulatory
decisions.

The
EPA
should
not
include
pre­
combustion
removal
technologies
unless
there
has
been
adequate
flue
gas
testing
at
sufficiently
representative
generating
plants
to
ensure
that
performance
can
be
adequately
characterized.
Given
the
uncertainties
and
complexities
of
Hg
flue
gas
chemistry
it
is
inappropriate
to
assume
that
reductions
in
coal
Hg
content
achieved
in
small
9­
23
scale
testing
will
reflect
the
reductions
flue
gas
Hg
content
that
may
be
achieved
if
and
when
potential
pre­
combustion
technologies
are
commercialized.

The
commenter
said
that
it
would
be
arbitrary
and
unreasonable
to
base
an
emissions
standard
on
the
hypothetical
performance
of
unproven
technology.

Response:

EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
stated
that
absent
a
rational
basis,
EPA
should
not
make
assumptions
about
reduced
capital
and
maintenance
and
operating
costs
for
ACI.
Alternatively,
they
believe
that
EPA
should
model
a
case
where
demand,
coupled
with
supply
constraints,
dries
up
capital
and
operating
costs,
in
particular
for
the
activated
carbon
sorbent.

World
consumption
of
activated
carbon
is
expected
to
increase
by
4
percent
per
year
from
its
current
level
of
750,000
ton/
year,
effectively
using
up
planned
production
capacity
increases
by
2005.
Two­
thirds
of
the
planned
capacity
expansion
is
in
China
or
Southeast
Asia,
while
production
facilities
in
the
U.
S.
are
being
shut
down.
The
availability
and
cost
of
activated
carbon
is
significant
because
all
of
the
modeling
results
EPA
presents
in
the
NODA
assume
the
application
of
ACI
to
meet
the
2010
compliance
requirements,
applied
to
10
GW
to
120
GW
of
generating
capacity.
At
a
10
lb/
MM
SCF
treat
rate,
this
would
require
60,000
to
700,000
lb/
year
of
activated
carbon.
Therefore,
there
is
the
potential
that
demand
for
activated
carbon
in
the
U.
S.
could
create
supply
shortages
and
corresponding
price
increases.

EPA
should
not
model
control
options
that
have
not
been
demonstrated
on
a
commercial
basis.
As
noted
in
our
comments
dated,
June
29,
2004,
this
does
not
mean
a
control
technology
that
a
vendor
is
willing
to
sell,
but
a
technology
that
performs
in
a
predictable
manner
when
used
with
boilers
of
various
designs
over
the
range
of
operating
conditions
that
the
plant
will
encounter.
Short­
term
field
tests
or
demonstration
projects
are
not
sufficient
to
conclude
that
a
technology
is
commercially
available.
Modeling
based
on
the
hypothetical
performance
of
unproven
technologies
will
produce
speculative
results
and
cannot
be
used
to
determine
the
performance
of
the
technology
for
specific
units
with
a
high
degree
of
confidence.
Such
information
should
not
form
the
basis
for
regulatory
decisions.

Response:

Given
that
the
first
phase
cap
is
set
at
the
Hg
co­
benefits
of
CAIR,
EPA
does
not
project
significant
amount
of
ACI
to
be
retrofitted
until
the
2018
timeframe.
With
regard
to
demand
for
activated
carbon,
EPA
notes
that
markets
respond
to
the
demand
for
materials,
much
like
under
9­
24
the
NOx
SIP
call
supply
for
catalyst
increased
with
demand.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
October
2002,
in
docket.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5488)
said
that
EPA
should
further
modify
its
power
sector
modeling
to
treat
control
choices
more
realistically.
EPA
should
configure
the
model
to
allow
for
retrofit
applications/
upgrades
of
fabric
filters
and
to
allow
for
pre­
cleaning
and
coal
blending
as
control
options.
EPA
should
also
include
halogenated
sorbents
as
a
highly
cost­
effective
control
option.
Furthermore,
EPA
has
assumed
that
sources
must
either
control
emissions
at
the
90
percent
level
with
a
fabric
filter
or
at
the
60
percent
level
using
ACI
alone.
This
discontinuous
and
unrealistic
choice
is
likely
to
inflate
estimated
control
costs
and
needs
to
be
modified.

Response:

EPA's
IPM
model,
due
to
model
run
time
constraints,
has
to
limit
the
number
of
control
retrofit
options
available.
The
ACI
option
in
EPA'
s
IPM
includes
the
addition
of
a
pulse­
jet
fabric
filter
to
achieve
90%
control.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
stated
that
EPA
has
requested
comment
on
whether
other
control
options
should
be
considered
in
EPA's
power
sector
modeling
(
e.
g.,
retrofit
of
fabric
filters
and
electrostatic
precipitators,
pre­
combustion
controls,
and
the
optimization
of
SO
2
or
NO
x
controls).
The
answer
is
yes.
The
commenter
noted
that
EPA
has
had
this
information
readily
available
since
2001
when
EPA's
Office
of
Research
and
Development
published
a
report
that
described
a
number
of
retrofit
options
that
could
be
undertaken
to
optimize
the
Hg
capture
of
conventional
controls.
In
addition,
EPA
had
this
information
in
hand
in
June
2002
when
revisions
to
the
IPM
were
being
discussed
with
the
Utility
Working
Group.
These
eleventh
hour
revisions
to
IPM
clearly
could
have
been
made
more
than
2
years
ago.

Response:

EPA's
IPM
model,
due
to
model
run
time
constraints,
has
to
limit
the
number
of
control
retrofit
options
available.
The
ACI
option
in
EPA'
s
IPM
includes
the
addition
of
a
pulse­
jet
fabric
filter
to
achieve
90%
control.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
9­
25
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

The
commenter
(
OAR­
2002­
0056­
5455)
wanted
to
fully
reference
the
Forest
County
Potawatomi
Community's
(
FCPC)
excellent
comment
letter
to
EPA
on
the
Hg
utility
rule
(
Document
ID
No.
OAR­
2002­
0056­
2173).
The
experts
retained
by
the
FCPC
stated
in
attachments
to
that
letter
why
EPA's
proposed
MACT
standards
were
unacceptable
and
why
EPA
improperly
failed
to
consider
alternate
methods
of
removal,
such
as
activated
carbon
injection.
We
were
unable
to
make
specific
comments
on
these
issues
as
time
was
running
short.
The
commenter
also
felt
they
could
not
add
anything
to
the
discussion
that
had
not
already
been
said
in
the
FCPC
letter.
Comments
made
by
Catherine
O'Neill
in
her
article
"
Mercury,
Risk,
and
Justice"
also
captured
the
viewpoint
of
Fond
de
Lac
Band.

Response:

As
explained
in
the
final
rule
preamble,
EPA
is
finalizing
mercury
reduction
requirements
for
coal­
fired
power
plants
under
section
111.
Also
see
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
and
preambles
to
the
rules.

Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
EPA
should
consider
other
pollution
control
and
pollution
prevention
measures
in
its
power
sector
modeling.
The
commenter
further
stated
that
some
of
the
measures
EPA
should
be
focused
on
are
addressed
in
a
recent
report
prepared
by
the
National
Wildlife
Federation,
a
copy
of
which
is
attached
as
Exhibit
E
(
See
Document
ID
No.
OAR­
2002­
0056­
5460.).

Response:

EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
noted
that
EPA
proposed
adopting
those
coal
rank
allocation
adjustment
factors
for
the
2010
cap
based
on
"
equitable"
grounds,
with
allocations
adjusted
by
coal
rank
to
"
reflect
the
concern
that
installation
of
PM,
NO
x
and
SO2
control
equipment
on
different
coal
ranks
results
in
different
Hg
removal."
However,
since
EPA
is
relying
upon
other
Hg­
specific
technologies
to
meet
any
subsequent
cap
beyond
co­
benefits,
performance
of
PM,
NO
x
and
SO
2
control
technologies
on
coal
ranks
for
any
later
cap
would
seem
to
be
irrelevant.
The
relevant
question
is
whether
there
is
anything
in
EPA's
projected
9­
26
availability
of
Hg­
specific
controls
by
at
least
2014
that
provides
any
equitable
basis,
supported
by
technical
concerns,
to
award
additional
allowances
to
lower
rank
coals
(
and,
thereby,
take
them
away
from
bituminous
coal).

Response:

As
discussed
in
the
Chapter
5,
section
5.6.1,
EPA
is
finalizing
coal
adjustment
factors
for
the
purpose
of
establishing
state
emission
budgets
of
1.0
for
bituminous
coals,
1.25
for
subbituminous
coals,
and
3.0
for
lignite
coals.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
noted
that,
in
the
NODA,
EPA
asked
for
comment
as
to
whether
disparities
in
current
NO
x
and
SO
2
Hg
control
capability
among
coal
ranks
justifies
using
different
emissions
trading
allocation
adjustment
factors
for
each
coal
rank
to
reflect
this
disparity.
In
the
commenter's
opinion
they
did
not.
The
point
of
co­
benefits­
based
Hg
emission
reductions
proposed
by
EPA
is
that
the
Hg
reductions
required
to
meet
the
proposed
cap
are
made
as
a
result
of
CAIR
co­
benefits,
and
no
unit
has
to
install
controls
specifically
to
reduce
Hg.
Hence,
the
specific
ability
of
a
unit
(
or
the
coal
rank
it
is
using)
to
make
Hg
reductions
is
largely
irrelevant.
Those
that
do
need
"
reductions"
to
meet
their
allowance
allocations
get
them
through
allowance
purchases,
and
the
ability
of
and
cost
to
any
particular
unit
to
acquire
allowances
does
not
vary
by
coal
rank.
Notably,
none
of
the
units
in
the
non­
CAIR
states,
where
a
large
portion
of
subbituminous
coal
is
consumed,
have
to
make
any
Hg
reductions,
and
hence
their
ability
to
do
so,
regardless
of
coal
rank,
is
irrelevant.

Response:

As
discussed
in
the
Chapter
5,
section
5.6.1,
EPA
is
finalizing
coal
adjustment
factors
for
the
purpose
of
establishing
state
emission
budgets
of
1.0
for
bituminous
coals,
1.25
for
subbituminous
coals,
and
3.0
for
lignite
coals.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

While
the
coal
adjustment
are
used
for
determining
the
state
budgets
and
are
used
in
EPA's
example
unit
allocation
methodology,
each
State
or
Tribe
is
given
discretion
on
how
to
distribute
the
allocations
within
a
State
or
Tribe.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
it
is
important
to
note
that
the
required
levels
of
industry­
wide
Hg
reductions
happen
"
automatically"
as
a
result
of
co­
benefits
in
aggregate.
Consequently,
in
aggregate,
there
is
no
obligation
for
any
unit
to
actually
install
any
control
equipment
specifically
to
meet
a
Hg
reduction
requirement.
EPA's
proposal
declares,
and
fundamentally
rests
upon,
the
principle
that
no
unit
should
have
to
install
any
controls
specifically
to
reduce
Hg,
as
such
controls
are
not
plausibly
cost
effective.
Because
the
level
of
co­
benefits
9­
27
Hg
reductions
that
will
be
achieved
under
the
CAIR
includes
different
reduction
assumptions
for
each
of
the
coal
ranks,
differences
in
actual
Hg
reductions
among
coal
ranks
have
already
been
accounted
for
in
setting
the
industry­
wide
co­
benefits
cap.

As
a
consequence
of
the
co­
benefits
approach,
neither
EPA
nor
the
commenters
referenced
in
the
NODA
may
rationally
award
differing
amounts
of
allowances
to
the
various
coal
ranks
based
on
the
notion
that
members
of
any
coal
rank
will
have
to
install
controls
to
reduce
Hg.
To
do
so
would
be
to
declare
such
Hg­
only
controls
technically
and
economically
unjustified
as
the
best
system
of
reductions
under
section
111
on
the
one
hand,
but
to
act
as
if
such
controls
were
required
when
allocating
allowances,
on
the
other.
Hence,
relative
abilities
among
coal
rank
to
control
Hg
under
the
CAIR
or
otherwise
are
generally
irrelevant.

While
Hg
control
disparities
among
coal
ranks
and
associated
equities
are
not
relevant
in
aggregate
under
EPA's
co­
benefits
approach,
they
may
seem
to
be
relevant
at
the
individual
unit
level,
and
therefore
further
analysis
is
required.
The
co­
benefits
approach
creates
two
general
classes
of
utility
units:
those
that
will
install
co­
benefits
technology
and
those
that
will
not.
More
specifically,
for
compliance
purposes,
two
classes
of
utility
units
are
created:
those
that
buy
allowances
to
comply,
and
those
that
are
selling
allowances
based
on
their
co­
benefits
reductions.

Response:

As
discussed
in
the
Chapter
5,
section
5.6.1,
EPA
is
finalizing
coal
adjustment
factors
for
the
purpose
of
establishing
state
emission
budgets
of
1.0
for
bituminous
coals,
1.25
for
subbituminous
coals,
and
3.0
for
lignite
coals.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
the
use
of
ACI
with
an
electrostatic
precipitator
(
ESP)
has
inherent
uncertainties
that
may
require
the
retrofit
of
additional
collecting
surface
area
for
the
ESP.
The
retrofit
of
an
additional
field
may
be
required
to
enable
the
existing
ESP
to
maintain
particulate
matter
control
efficiency.
Given
the
uncertainties,
many
ESPs
may
have
to
be
rebuilt
with
an
increase
in
collecting
surface
area,
to
provide
Hg
control
and
retain
control
of
particulate
matter
emissions.
The
commenter
has
provided
assumptions
that
would
allow
ESPs
that
need
additional
plate
area
to
accommodate
ACI
and
have
assigned
a
$
25/
kW
capital
charge
for
adding
the
extra
field.
However,
that
retrofit
of
an
additional
field
may
not
be
feasible
in
all
instances,
and
the
$
25/
kW
capital
charge
for
adding
the
extra
field
is
based
on
situations
conducive
to
such
additions.

The
commenter
rejected
the
suggestion
that
fabric
filters
can
be
widely
retrofit
to
control
particulate
matter
and
significantly
enhance
Hg
removal.
Fabric
filters
are
not
feasible
where
flue
gas
SO
3
concentrations
exceed
about
5
ppm.
It
is
possible
that
an
engineering
solution
to
the
effects
of
high
SO
3
concentrations
on
fabric
filters
may
eventually
be
commercially
available.
Indeed,
a
panel
session
at
the
2004
Mega­
Symposium
discussed
possible
solutions
to
such
problems,
but
none
are
anywhere
near
proven
at
this
time.
Also,
fabric
filters
are
not
practical
for
service
in
water­
saturated
flue
gas
conditions
such
as
experienced
downstream
from
wet
9­
28
scrubbers,
since
the
water
entrained
in
the
flue
gas
will
mix
with
the
ash
entrained
on
the
filter,
sealing
off
gas
flow
and
fouling
the
filter
surface.

Response:

As
explained
in
the
final
rule
preamble,
EPA
is
finalizing
mercury
reduction
requirements
for
coal­
fired
power
plants
under
section
111,
as
such
EPA
is
not
mandating
a
specific
control
technology
for
compliance.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
the
NODA
had
requested
further
comment
on
the
prospects
of
technological
change
in
Hg
control
technology,
on
how
it
can
be
reflected
appropriately
in
models,
and
on
how
it
might
affect
policy
choices.
In
response,
the
commenter
has
extended
their
analyses
of
technological
change
to
attempt
to
reflect
future
availability
of
new
control
methods
that
have
just
recently
begun
to
be
tested
and
show
promise
of
being
cost­
effective,
especially
for
western
coals
or
power
plants
equipped
with
hot­
side
ESPs.
Significant
questions
remain
about
this
new
method's
ultimate
cost,
control
effectiveness,
applicability
to
different
types
of
units,
balance­
of­
plant
issues,
and
timing
of
commercial
availability.
However,
once
analyzed
its
potential
impact
on
a
"
what
if"
basis
using
a
range
of
assumptions
related
to
these
questions.

EPRI
researchers
provided
information
on
"
chemically­
treated
carbons"
(
CTC),
a
specific
emerging
advancement
in
sorbent
technologies
that
would
reduce
the
variable
and
capital
costs
of
Hg
controls.
It
is
believed
that
these
sorbents
could
become
available
for
installations
as
early
as
2010,
and
would
allow
the
injection
rate
of
the
sorbent
to
be
dramatically
reduced
for
a
given
percentage
removal,
reaching
80
percent
or
more
at
subbituminous
and
lignite
units
without
the
use
of
a
fabric
filter
or
COHPAC.

The
commenter
has
used
the
EPMM
model
to
explore
the
impact
of
the
CTC
option
becoming
available
at
a
future
date
(
ranging
from
2010
to
2012)
under
both
the
cap­
and­
trade
policy
and
the
MACT
policy.
It
was
assumed
that
any
controls
undertaken
prior
to
that
date
would
have
to
rely
on
the
more
costly
conventional
activated
carbons
with
which
the
industry
has
greater
experience
to
date.
In
order
to
achieve
removals
that
can
be
as
high
as
90
percent
on
lower
rank
coals,
sorbent
injection
with
conventional
sorbents
requires
the
large
capital
investment
in
a
COHPAC
(
unless
a
unit
already
has
a
fabric
filter).
Even
with
bituminous
coal,
the
cost­
effective
means
of
achieving
90
percent
removal
with
present
technology
also
entails
the
COHPAC
investment
because
the
sorbent
injection
rate
would
be
very
high
without
the
COHPAC
than
with
it
(
e.
g.,
about
20
lb/
Macf
without
it,
compared
to
about
2.5
lb/
Macf
with
it).

There
is
still
much
uncertainty
on
the
cost
and
effectiveness
of
all
sorbent
injection
technologies,
but
especially
the
newer
CTC
option.
Using
information
provided
by
EPRI
researchers,
"
optimistic"
and
"
pessimistic"
CTC
cases
were
prepared.
The
"
optimistic"
case
assumed
that
CTC
would
not
affect
a
company's
ability
to
continue
to
sell
its
fly
ash
for
use
in
9­
29
concrete
manufacture
and
other
current
commercial
uses;
that
the
CTC
technology
will
be
available
in
time
for
those
plants
that
choose
it
as
their
preferred
Hg
control
method
to
meet
a
compliance
date
of
2010;
and
that
it
would
be
made
to
work
for
bituminous
units
as
well.
The
"
pessimistic"
case
assumed
that
if
CTC
were
used,
the
unit's
fly
ash
would
no
longer
be
viable
for
concrete
use;
that
it
would
be
available
in
2010,
but
at
an
operating
cost
that
would
be
three
times
more
expensive
than
it
would
become
by
2012;
and
that
it
would
not
provide
cost­
effective
options
for
bituminous
units.

The
effects
of
adding
the
CTC
technology
assumptions
to
the
base
EPMM
scenario
reflecting
the
Hg
cap­
and­
trade
policy
were:

°
The
total
number
of
Hg
control
retrofits
is
not
much
changed,
but
the
fraction
of
retrofitted
capacity
that
uses
the
CTC
technology
ranges
from
27
percent
to
64
percent.

°
There
is
no
significant
effect
on
the
emission
glide
path.
Emissions
in
2020
fall
to
15.5
tons,
compared
to
15.4
in
the
standard
case.

°
Marginal
costs
of
Hg
control
are
reduced
slightly
compared
to
the
case
that
does
not
have
CTC,
such
that
they
are
generally
in
the
range
of
$
20,000
to
$
30,000/
lb
(
1999$)
through
2020.

°
Costs
of
the
proposed
Hg
cap­
and­
trade
scenario
fall
by
5
to
30
percent
(
in
the
pessimistic
and
optimistic
cases,
respectively)
relative
to
the
same
modeled
scenario
that
does
not
contain
CTC
technology.

In
contrast,
the
effects
of
the
CTC
assumptions
on
the
MACT
policy
were
very
minor:

1.
The
total
number
of
Hg
control
retrofits
required
by
2008
continues
to
be
very
high,
with
over
67
GW
of
FGDs
and
over
64
GW
of
ACI­
based
controls
required
by
2008.

2.
Only
about
10
percent
of
capacity
uses
the
CTC
technology
to
meet
the
MACT.
Those
10
percent
do
this
by
moth­
balling
during
2010­
2011.
The
avoided
capital
costs
of
COHPAC
offset
their
lost
revenues,
making
waiting
their
preferred
option.

3.
Emissions
in
2008
remain
at
about
32
tons,
and
fall
to
about
30
tons
by
2020,
as
in
our
original
MACT
case.

4.
Costs
of
the
proposed
MACT
scenario
are
effectively
unchanged
from
the
case
without
the
CTC
technology:
$
9.9
billion
(
1999$)
compared
to
the
original
cost
estimate
of
$
10.1
billion
(
1999$).

These
model
results
demonstrate
what
simple
common
sense
is:
if
a
MACT
policy
is
implemented
very
soon,
while
relevant
technologies
are
still
in
the
early
phases
of
innovation,
it
will
be
unable
to
benefit
from
technological
improvement.
These
analyses
do
add
some
further
value,
however:

1.
They
provide
an
example
of
the
impact
of
technological
improvement
on
Hg
control
9­
30
performance
and
costs
through
the
case
study
of
a
specific
technology.

2.
They
place
a
quantitative
range
on
the
potential
cost
reduction
that
this
line
of
research
might
provide
under
a
flexible,
phased­
in
Hg
policy.

3.
They
make
it
clear
that
the
main
beneficiaries
of
this
potential
innovation
in
Hg
control
technology
under
a
MACT
will
be
the
marginal
coal
units
that
have
small
revenue
prospects
to
start
with,
whereas
a
large
portion
of
the
universe
of
coal
units
can
benefit
from
such
an
innovation
under
the
more
flexibly­
timed
cap­
and­
trade
approach.

Based
on
these
data,
the
commenter
believed
that
technological
advance
in
the
specific
form
of
chemically­
treated
carbon
sorbents
could
reduce
the
estimated
costs
of
the
proposed
capand
trade
policy
to
a
significant
degree,
but
it
would
provide
no
significant
reduction
in
the
costs
of
the
alternative
MACT
approach.
In
all,
the
main
message
regarding
technological
change
is
that
its
benefits
are
largely
lost
in
a
MACT
setting,
or
in
a
setting
that
requires
controls
to
be
installed
very
rapidly.
When
a
policy
is
designed
to
allow
flexibility
to
adjust
timing
of
controls,
and
to
create
sustained
incentives
to
continue
to
reduce
costs
by
pricing
every
unit
of
emissions,
then
costs
of
control
may
be
moderated.

Response:

As
explained
in
the
final
rule
preamble,
EPA
is
finalizing
mercury
reduction
requirements
for
coal­
fired
power
plants
under
section
111.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

3.
To
the
extent
that
additional
control
considerations
should
be
included,
EPA
is
seeking
data
on
the
time
line
for
commercialization,
cost,
balance
of
plant
issues,
and
performance
of
such
options.

Comment:

One
commenter
(
OAR­
2002­
0056­
5484)
noted
that
over
the
past
several
months,
pollution
control
equipment
vendors
have
made
many
public
pronouncements
regarding
the
effectiveness
of
their
equipment
for
Hg
control.
Unfortunately,
when
those
same
vendors
are
asked
to
guarantee
Hg
removal
efficiency
in
contracts
that
they
sign
with
their
utility
customers,
the
control
levels
that
they
are
willing
to
guarantee
are
much
less
than
the
optimistic
claims
they
have
made
in
public
forums.
For
example,
the
commenter
has
signed
an
agreement
with
a
major
vendor
to
supply
an
SO
2
scrubber,
which
will
also
capture
some
of
the
Hg
emissions.
The
differences
between
the
public
statements
of
this
supplier
and
the
actual
contract
language
are
described
in
Attachment
2
in
of
Docket
ID
No.
OAR­
2002­
0056­
5484.

Response:

The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
9­
31
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5484)
noted
that
EPA's
proposed
Clean
Air
Mercury
Rule
would
require
continuous
monitoring
of
Hg
emissions
from
electric
utility
steam
generating
units,
either
through
the
installation
of
Continuous
Emissions
Monitoring
systems
(
CEMs)
or
through
another
appropriate
method,
such
as
proposed
Method
324,
Determination
of
Vapor
Phase
Flue
Gas
Mercury
Emissions
From
Stationary
Sources
Using
Dry
Sorbent
Trap
Sampling.
However,
EPA's
March
16,
2004,
supplemental
proposal
states
that
Method
324
would
only
be
available
under
certain
limited
circumstances,
such
as
only
for
low­
emitting
units,
or
if
quarterly
relative
accuracy
test
audits
(
RATAs)
are
performed.
The
commenter
is
concerned
that
such
limitations
will
unnecessarily
limit
the
applicability
of
Method
324,
and,
therefore,
commissioned
RMB
Consulting
and
Research
to
develop
the
attached
report,
"
Review
of
an
Alternative
Method
for
Continuous
Mercury
Emission
Measurement:
Method
324
 
Determination
of
Vapor
Phase
Flue
Gas
Mercury
Emissions
from
Stationary
Source
Using
Dry
Sorbent
Trap
Sampling."
This
report
concludes
that
Method
324,
also
known
as
the
EPRI
Quick
SEMTM
method,
provides
results
comparable
to
both
Hg
CEMs
and
to
the
Ontario
Hydro
reference
method.

The
EPA
has
expressed
concern
that
in
order
to
administer
a
cap
and
trade
program,
realtime
Hg
emissions
information
is
necessary
and,
therefore,
CEMs
will
be
necessary.
However,
the
commenter
wishes
to
emphasize
that
Quick
SEMTM
does
provide
continuous
sampling
and
laboratories
are
developing
analytical
methodologies
that
will
allow
sample
results
to
be
available
in
hours,
instead
of
the
days
that
were
previously
required.
Therefore,
Quick
SEMTM
results
will
be
available
in
time
to
provide
information
necessary
for
administration
of
a
cap
and
trade
program.
The
commenter
urges
EPA
to
promulgate
Method
324
without
restrictions
on
its
use.

Response:

EPA
agrees
with
the
commenter.
In
light
of
comparative
field
data,
EPA
believes
that
monitoring
using
sorbent
media
should
be
as
similar
as
possible
to
monitoring
using
Hg
CEMS
and
therefore
Section
75.81(
a)
of
the
final
rule
allows
the
use
of
sorbent
trap
systems
for
any
affected
unit,
provided
that
rigorous,
technology­
specific
QA
procedures
are
implemented.
The
operational
and
QA/
QC
procedures
for
sorbent
trap
systems
are
found
in
section
75.15
and
in
appendices
B
and
K
of
the
final
rule.

Recent
field
test
data
from
several
different
test
sites
indicate
that
sorbent
trap
systems
can
be
as
accurate
as
Hg
CEMS.
However,
EPA
notes
that
although
the
restrictions
on
the
use
of
sorbent
traps
have
been
removed,
there
are
some
inherent
risks
associated
with
the
use
of
this
technology.
For
instance,
because
sorbent
traps
may
contain
several
days
of
accumulated
Hg
mass,
the
potential
exists
for
long
missing
data
periods,
if
the
traps
should
be
broken,
compromised,
or
lost
during
transit
or
relative
accuracy
test
audit
(
RATA)
of
a
sorbent
trap
system
is
performed,
the
results
of
the
test
cannot
be
known
until
the
contents
of
the
traps
have
been
analyzed.
If
the
results
of
the
analysis
are
unsatisfactory,
the
RATA
may
have
to
be
9­
32
repeated.
This
also
may
resulting
in
a
long
missing
data
period.
However,
EPA
believes
that
these
undesirable
outcomes
can
be
minimized
by
following
the
proper
handling,
chain
of
custody,
and
laboratory
certification
procedures
in
the
final
rule.
The
use
of
redundant
backup
monitoring
systems
can
also
help
to
reduce
the
amount
of
missing
data
substitution.

Comment:

One
commenter
(
OAR­
2002­
0056­
5556)
noted
that
the
EPA
appropriately
cites
the
Detroit
Edison,
St.
Clair,
Michigan
pilot
study
on
page
69870
in
the
Federal
Register.
This
study
is
important
in
that
it
documents
the
successful
application
of
the
brominated
powdered
activated
carbon
(
B­
PACTM)
process
at
the
existing
DTE
Energy's
Detroit
Edison
St.
Clair
Power
Plant
in
August
2004.
This
preliminary
30­
day
pilot
study
conducted
as
part
of
the
U.
S.
Department
of
Energy's
National
Energy
Technology
Laboratory's
"
Advanced
Utility
Mercury­
Sorbent
Field­
Testing
Program"
demonstrated
a
94
percent
Hg
control
with
B­
PACTM
injected
into
a
cold­
side
electrostatic
precipitator.
This
commenter
noted
that
this
study
also
demonstrated
an
85
percent
cost
reduction
from
the
current
technology
cost
baseline
(
Nelson,
S.
2004
and
McCoy,
M.,
et.
al.,
2004),
and
believes
the
final
study
should
be
factored
into
the
EPA's
analysis
and
regulatory
decision.

Response:

EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5556)
noted
that
in
the
NODA,
the
EPA
states
that
the
Integrated
Planning
Model
utilized
"
finds
the
least­
cost
solution
to
meeting
electricity
demand
subject
to
environmental,
transmission,
reserve
margin,
and
other
system
operating
constraints
for
any
specified
region
and
time
period."
Since
the
goal
of
the
MACT
standard
is
not
to
find
a
"
least­
cost"
solution
but
rather
a
"
best
technology"
solution,
a
model
based
on
"
least­
cost"
is
not
appropriate.
Whatever
modeling
approach
the
EPA
utilizes
in
its
final
analysis
should
be
technology­
driven
and
used
to
set
a
true
MACT
floor
under
Section
112
of
the
CAA.

Response:

EPA
uses
IPM
to
analyze
the
projected
impact
of
environmental
policies
on
the
electric
power
sector
in
the
48
contiguous
States
and
the
District
of
Columbia.
IPM
is
a
multi­
regional,
dynamic,
deterministic
linear
programming
model
of
the
U.
S.
electric
power
sector.
EPA
used
IPM
to
project
both
the
national
level
and
the
unit
level
of
utility
unit
Hg
emissions
under
different
control
scenarios.
EPA
also
used
IPM
to
project
the
costs
of
those
controls.
As
explained
in
the
final
rule
preamble,
EPA
is
finalizing
mercury
reduction
requirements
for
coalfired
power
plants
under
section
111.

Comment:
9­
33
One
commenter
(
OAR­
2002­
0056­
5591)
stated
that
EPA
has
requested
comment
concerning
the
availability
of
sorbent
injection
technologies
to
serve
the
electric
power
market.
Activated
carbon
injection
equipment
is
currently
being
sold
to
utilities.
ACI
equipment
is
identical
for
all
coal
types
including
bituminous,
subbituminous,
lignites
and
blends.
Therefore,
ACI
equipment
can
be
purchased
for
all
coals
and
all
plant
configurations.

The
specific
sorbents
may
vary
for
different
coals
and
operating
conditions.
In
addition,
the
ability
to
accurately
predict
the
levels
of
Hg
removal
that
will
be
achieved
will
vary
for
different
coals
depending
on
the
available
performance
data.
For
example,
there
have
been
a
significant
number
of
tests
over
the
past
year
and
a
half
on
PRB
coals
and
North
Dakota
lignites.
Therefore,
it
is
possible
to
estimate
results
for
these
configurations.
There
is
less
data
on
bituminous
coals,
so
predictions
will
be
less
precise.
Several
full­
scale
field
tests
will
be
conducted
on
bituminous
coals
during
2005
and
2006.
The
first
test
on
a
Texas
lignite
will
be
conducted
in
2005.
Until
this
occurs,
it
is
difficult
to
predict
performance
on
Texas
lignite.

The
performance
of
activated
carbon
injection
systems
for
lignite,
subbituminous,
and
bituminous
coals
on
various
coal­
fired
power
plant
configurations
are
given
in
Table
1.
The
Hg
reduction
performance
for
these
power
plant
scenarios
are
based
on
results
from
full­
scale
demonstrations
that
have
been
documented
in
various
technical
papers
presented
at
major
electric
power
conferences.

Table
1.
Activated
Carbon
Injection
Control
Technology
Options
Plant
Configuration
Technolog
y
Coal
Type
%
Reduction
Costc
Year
Commer
c­
ially
Availabl
e
Min
Ma
x
Avg.
Totala
Avg.
Incrm.
b
Capital
($/
kW)
O&
M
($/
kWh
)

CESPd
ACJf,
g
Bit
50
90
70
70
1.5
to
3
.0012
2004
ACIg,
h
Sub
0
95
80
80
1.5
to
3
.0005
2004
ACIi
Lig
0
80
63
63
1.5
to
3
.0005
2004
CESP/
FGD
ACIj
Bit
50
90
70
70
1.5
to
3
.0012
2004
ACI
Sub
0
95
80
80
1.5
to
3
.0005
2004
ACIk
Lig
0
80
60
70
1.5
to
3
.0005
2004
CESP/
FGDdry
ACI
Bit
80
>
90
>
90
88
1.5
to
3
.00012
2004
ACI
Sub
0
90
80
85
1.5
to
3
.00017
2004
ACI
Lig
0
90
70
70
1.5
to
3
.00017
2004
CESP/
SCR/
FG
D
ACI
Bit
50
90
70
70
1.5
to
3
.0012
2004
ACI
Sub
0
95
80
80
1.5
to
3
.0005
2004
ACI
Lig
0
80
60
60
1.5
to
3
.0005
2004
Plant
Configuration
Technolog
y
Coal
Type
%
Reduction
Costc
Year
Commer
c­
ially
Availabl
e
Min
Ma
x
Avg.
Totala
Avg.
Incrm.
b
Capital
($/
kW)
O&
M
($/
kWh
)

9­
34
FF
ACJl
Bit
20
95
85
80
1.5
to
3
.00036
2004
ACJl,
m
Sub
20
90
90
80
1.5
to
3
.00054
2004
ACI
Lig
20
80
80
75
1.5
to
3
.00054
2004
FF/
FGD
ACI
Bit
50
95
90
70
1.5
to
3
.00012
2004
ACJl
Sub
30
90
90
80
1.5
to
3
.00027
2004
ACI
Lig
30
90
85
70
1.5
to
3
.00027
2004
FF/
SCR/
FGDdry
ACI
Bit
80
>
90
>
90
50
1.5
to
3
.00012
2004
ACIn
Sub
0
>
90
>
90
90
1.5
to
3
.00017
2004
ACIo
Lig
0
90
75
70
1.5
to
3
.00017
2004
FF/
SCR/
FGD
ACI
Bit
50
95
90
70
1.5
to
3
.00012
2004
ACI
Sub
30
90
90
80
1.5
to
3
.00027
2004
ACI
Lig
30
80
80
70
1.5
to
3
.00027
2004
HESPe
TOXECO
Np
Bit
20
95
85
80
3
+
15
to
3+
50
.00036
2004
TOXECO
N
Sub
20
90
90
80
3
+
15
to
3+
50
.00036
2004
TOXECO
N
Lig
20
80
80
70
3
+
15
to
3+
50
.00054
2004
HESP/
FGD
TOXECO
N
Bit
50
95
90
70
3
+
15
to
3+
50
.00012
2004
TOXECO
N
Sub
30
90
90
80
3
+
15
to
3+
50
.00036
2004
TOXECO
N
Lig
30
80
80
70
3
+
15
to
3+
50
.00027
2004
HESP/
FGDdry
TOXECO
N
Bit
80
>
90
>
90
50
3
+
15
to
3+
50
.00012
2004
TOXECO
N
Sub
0
>
90
>
90
90
3
+
15
to
3+
50
.00017
2004
TOXECO
N
Lig
0
90
88
70
3
+
15
to
3+
50
.00017
2004
HESP/
SCR/
FG
D
TOXECO
N
Bit
50
95
90
70
3
+
15
to
3+
50
.00012
2004
Plant
Configuration
Technolog
y
Coal
Type
%
Reduction
Costc
Year
Commer
c­
ially
Availabl
e
Min
Ma
x
Avg.
Totala
Avg.
Incrm.
b
Capital
($/
kW)
O&
M
($/
kWh
)

9­
35
TOXECO
N
Sub
30
90
90
80
3
+
15
to
3+
50
.00036
2004
TOXECO
N
Lig
30
80
80
70
3
+
15
to
3+
50
.00027
2004
a
This
is
the
percent
reduction
attributable
to
the
existing
pollution
controls
and
the
technology.
b
This
is
the
percent
reduction
attributable
only
to
the
technology.
c
In
EPA's
modeling,
is
it
appropriate
for
an
economic
forecast
to
assume
an
improvement
in
costs
over
time
(
such
as
through
technology
cost
reductions
or
through
future
technology
innovation).
d
CESP
­
represents
cold­
side
electrostatic
precipitator
e
HESP
­
represents
hot­
side
electrostatic
precipitator
f
Durham,
M.,
J.
Bustard,
T.
Starns,
C.
Martin,
R.
Schlager,
C.
Lindsey,
K.
Baldrey,
and
R.
Monso
(
2004).
"
Full­
Scale
Evaluations
of
Sorbent
Injection
for
Mercury
Control
on
Power
Plants
Burning
Bituminous
and
Subbituminous
Coals."
Power­
Gen
2002,
Orlando,
FL,
December
10­
12.
g
Nelson,
S.
Jr.,
R.
Landreth,
Q.
Zhou,
J.
Miller
(
2004).
"
Accumulated
Power­
Plant
Mercury
Removal
Experience
with
Brominated
PAC
Injection."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
DC,
August
30
­
September
2.
h
Starns,
T.
Sjostrom,
S.,
J.
Bustard,
M.
Durham
et
al
(
2004).
"
Full­
Scale
Evaluation
of
Mercury
Control
by
Injecting
Activated
Carbon
Upstream
of
a
Spray
Dryer
and
Fabric
Filter."
Presented
at
PowerGen
2004,
Orlando,
FL,
November
30
­
December
4.
I
Thompson,
J.
D.,
J.
Pavlish,
and
M.
Holmes
(
2004).
"
Enhancing
Carbon
Reactivity
for
Mercury
Control:
Field
Test
Results
from
Leland
Olds."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29
­
September
2.
j
Dombrowski,
K.,
et.
al.,
(
2004).
"
Sorbent
Injection
for
Mercury
Control
Upstream
of
Small­
SCA
ESPs."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29­
September
2.
k
Starns,
T,
J.
Amrhein,
C.
Martin,
S.
Sjostom,
C.
Bullinger,
D.
Stockdill,
M.
Strohfus,
R.
Chang,
(
2004).
`'
Full­
Scale
Evaluation
of
TOXECONIFM
on
a
Lignite­
Fired
Boiler."
Presentation
at
the
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29September
2.
I
Ley.
T.,
T.
Ebner,
K.
Fisher,
R.
Slye,
R.
Patton,
R.
Chang,
(
2004).
"
Assessment
of
Low­
Cost
Novel
Sorbents
for
Coal­
Fired
Power
Plant
Mercury
Control."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29­
September
2.
m
Haythornthwaite,
S.,
S.
Sjostrom,
et.
al.,
(
1997).
"
Demonstration
of
Dry
Carbon­
Based
Sorbent
Injection
for
Mercury
Control
in
Utility
ESPs
and
Baghouses."
EPRI­
DOE­
EPA
Combined
Utility
Air
Pollutant
Control
Symposium,
Washington,
D.
C.,
August
25­
29.
n
Sjostrom,
S.,
et.
al.,
(
2004).
"
Full­
Scale
Evaluation
of
Mercury
Control
by
Injecting
Activated
Carbon
Upstream
of
a
Spray
Dryer
and
Fabric
Filter."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29
­
September
2.
9­
36
o
Machalek,
T.,
et.
al.,
(
2004).
"
Full­
Scale
Activated
Carbon
Injection
for
Mercury
Control
in
Flue
Gas
Derived
from
North
Dakota
Lignite."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29­
September
2.
p
Berry,
M,
J.
Bustard.,
et.
al.,
(
2004).
"
Field
Test
Program
for
Long­
Term
Operation
of
a
COHPAC@
System
for
Removing
Mercury
from
Coal­
Fired
Flue
Gas."
Combined
Power
Plant
Air
Pollutant
Control
Mega
Symposium,
Washington,
D.
C.,
August
29­
September
2.

The
commenter
said
that
companies
are
providing
firm
price
proposals
with
performance
guarantees
for
every
coal
and
boiler
type.
Activated
carbon
injection
equipment
is
currently
being
sold
to
utilities.
ACI
equipment
is
identical
for
all
coal
types
including
bituminous,
subbituminous,
lignites
and
blends.
Therefore,
ACI
equipment
can
be
purchased
for
all
coals.

The
material
resources,
labor
and
time
required
to
install
the
control
equipment
is
an
additional
topic
to
consider.
With
regards
to
the
items
that
impact
APC
vendors,
there
are
sufficient
fabrication/
manufacturing
resources
in
the
U.
S.
market
to
support
a
rapid
retrofit
of
the
industry
with
sorbent
injection
systems
in
addition
to
the
systems
required
for
the
Clean
Air
Interstate
Rule.
These
systems
are
relatively
simple
compared
to
FGD
and
SCR
systems
and
the
major
components
are
commonly
used
in
a
variety
of
industrial
processes
from
numerous
manufacturers
throughout
the
U.
S.

As
mentioned
in
the
commenter's
previous
comments
on
EPA's
proposed
Hg
rule,
there
is
significant
excess
production
capacity
of
powder
activated
carbon
and
a
strong
interest
in
investing
significant
capital
in
building
new
production
facilities
exists
among
current
suppliers
(
both
in
the
U.
S.
and
in
China).
A
new
Hg
regulation
would
create
a
significant
new
market
for
activated
carbon.
In
order
to
build
new
production
capacity,
between
a
two­
to
four­
year
period
would
be
needed
to
expand
production.
However,
all
of
the
activated
carbon
suppliers
said
that
they
would
be
hesitant
to
invest
capital
resources
to
increase
capacity
based
only
on
the
promise
of
a
new
regulation.
A
decade
or
so
ago,
the
AC
industry
increased
capacity
when
EPA
announced
that
they
were
going
to
tighten
up
drinking
water
standards.
After
the
new
capacity
was
added,
EPA
did
not
follow
up
with
new
regulations,
which
produced
a
glut
of
activated
carbon.
Some
companies
went
out
of
business
because
of
this,
and
the
industry
as
a
whole
is
just
now
recovering.
As
a
result,
it
is
unlikely
that
new
AC
production
will
move
beyond
the
planning
stages
until
there
is
the
certainty
of
a
regulation.

Concerning
resources
for
fabric
filter
systems,
should
the
market
dictate
the
need
for
secondary
PM
control
(
not
all
applications
will
require
this)
there
will
be
sufficient
engineering
and
material
resources
to
complete
the
necessary
projects.
There
are
several
examples
where
the
industry
has
had
to
retrofit
a
significant
number
of
boilers
with
APC
controls
to
meet
new
environmental
regulations.
Examples
include
the
retrofit
of
ESPs
in
the
1970s
and
the
more
recent
retrofit
of
almost
100
GW
of
SCRs
for
the
NO
x
SIP
Call.
These
examples
support
the
assertion
that,
should
the
utility
industry
need
to
retrofit
a
large
number
of
coal­
fired
boilers
with
Hg
controls,
it
can
be
accomplished
in
a
short
period
of
time.
The
industries
that
support
this
market
(
APC
suppliers,
fabricators,
construction
firms,
etc.)
have
repeatedly
demonstrated
their
ability
to
meet
rapidly
increasing
market
demand.
In
addition,
increasing
demand
for
systems
and
fabrication
can
also
be
met
by
foreign
suppliers
of
silos,
fabric
filter
systems,
fabrication
and
supply
of
PAC.
9­
37
If
there
is
a
bottleneck
in
retrofitting
the
U.
S.
fleet
of
coal­
fired
boilers,
it
is
not
likely
to
be
in
the
area
of
the
supply
of
capital
equipment
or
under
supply
of
sorbents
but
more
likely
to
be
impacted
by
issues
that
are
within
the
scope
of
the
utility
or
regulatory
community
itself.
Examples
include
areas
such
as
project
permitting/
PUC
approval,
availability
of
project
financing,
and
unit
outage
scheduling.
These
are
all
items
that
are
out
of
the
control
of
APC
vendors
but
may
impact
the
timing
for
control
installation.

The
commenter
noted
that
EPA
reported
that
the
Edison
Electric
Institute
(
EEI)
estimated
that
ACI
would
be
less
expensive
per
pound
of
Hg
removed
than
EPA
has
estimated.
Meanwhile,
other
power
industry
models
assumed
higher
capital
costs
for
ACI
than
EPA
in
its
modeled
scenarios.
EPA
is
seeking
comment
on
whether
its
assumptions
for
Hg
control
technology
costs
are
reasonable.

EPA
raised
several
questions
in
the
NODA
requesting
information
on
sorbent
injection
technologies
and
how
best
to
make
modeling
assumptions
to
reflect
current
and
future
capabilities
of
Hg
control
technologies.
One
of
the
questions
raised
by
EPA
was
concerning
the
use
of
discounted
variable
operating
costs
for
activated
carbon
injection
(
ACI).
EPA
questioned
whether
it
would
be
appropriate
for
an
economic
forecast
to
assume
an
improvement
in
costs
over
time
(
such
as
through
technology
cost
reductions
or
through
future
technology
innovation),
and
what
level
of
improvement
in
costs
to
assume.
Specifically,
EPA
questioned
whether
a
2.5
percent
annual
improvement
in
variable
operating
costs
for
ACI
should
be
incorporated
into
their
modeling
as
has
been
done
for
similar
power
sector
models.

In
regards
to
decreasing
costs,
it
is
appropriate
to
assume
that
the
cost
of
sorbent
technologies
will
decrease
with
time
due
to
equipment/
technology
innovation,
improvements
in
sorbent
removal
efficiencies,
and
the
reduction
in
sorbent
production
costs.
The
primary
cost
of
sorbent
injection
technology
is
due
to
sorbent
usage
so
the
largest
cost
reductions
are
likely
to
be
made
with
the
sorbent
costs.
The
capital
costs
for
ACI
are
relatively
low
as
the
equipment
is
mechanically
simple
compared
to
FGD
and
SCR
systems
for
coal­
fired
power
plants.
Activated
carbon
injection
systems
consist
of
a
bulk­
storage
silo;
blower/
feeder
system
to
convey
the
activated
carbon
from
the
silo
through
hard
piping
leading
to
the
flue
gas
duct;
and
injection
probes
located
in
the
flue
gas
duct.
Currently,
the
annual
operating
costs
for
these
systems
will
be
more
than
the
cost
to
construct
the
system.

Costs
are
expected
to
decrease
as
sorbents
are
developed
specifically
for
the
coal­
fired
boiler
application.
It
is
widely
known
that
the
current
sorbents
have
much
higher
capacity
for
Hg
removal
than
can
effectively
be
used
in
a
coal­
fired
power
plant
application.
This
is
because
the
injected
sorbent
will
be
rapped
off
the
plates
of
the
electrostatic
precipitator
or
cleaned
off
the
bags
of
the
fabric
filter
before
the
absorption/
adsorption
capacity
of
the
sorbent
has
been
fully
utilized.
Therefore,
work
is
being
done
to
produce
a
lower
capacity,
lower
cost
sorbent
that
will
be
more
appropriate
for
use
in
this
industry.

It
is
also
expected
that
technical
innovations
will
lead
to
lower
cost
sorbents.
For
example,
ADA­
ES
has
reported
improved
Hg
removals
on
full­
scale
tests
with
NORIT's
new
activated
carbon
named
E­
3.
These
tests
showed
that
significantly
higher
levels
of
Hg
could
be
removed
at
significantly
lower
feed
rates
than
earlier
tests
indicated.
With
this
kind
of
technology
improvement,
the
overall
cost
for
Hg
removal
will
decrease
over
this.
This
is
especially
true
for
9­
38
Western
coals
(
i.
e.,
lignite
and
subbituminous)
as
sorbent
injection
rates
are
expected
to
be
higher
for
those
units
yielding
a
drop
in
operating
costs
by
a
factor
of
two
to
four.
It
is
expected
that
similar
improvements
in
sorbents
will
result
in
similar
cost
reductions
for
bituminous
coals.

As
far
as
production
costs
are
concerned,
there
will
likely
be
a
reduction
in
cost
to
produce
sorbent
products
for
the
power
industry
due
to
economies
of
scale.
Currently,
activated
carbon
is
already
manufactured
by
numerous
vendors
for
a
wide
variety
of
customized
applications
requiring
inefficient
and
expensive
materials
handling
to
provide
the
different
treatments
and
particle
size
requirements.
In
addition,
the
demand
for
activated
carbon
is
seasonal
and
therefore
the
use
of
the
equipment
is
not
optimized.
To
meet
the
power
industry
demands,
it
is
likely
that
new
production
facilities
will
be
built
to
produce
only
a
few
products
so
there
will
be
an
increase
in
efficiency
and
reduction
in
cost.
In
addition,
the
power
market
will
be
much
more
consistent
and
predictable,
which
will
serve
to
optimize
the
production
equipment.

Once
the
sorbents
are
specifically
produced
for
power
industry
applications,
the
pricing
trend
for
activated
carbon
should
act
very
much
like
other
commodities.
On
average,
pricing
for
most
commodity
items
will
normally
stay
unchanged
or
decrease
slightly
over
time
as
market
forces
encourage
cost
reductions.
Since
inflation
in
the
U.
S.
normally
runs
around
2­
3
percent,
any
commodity
that
does
not
increase
in
price
decreases
(
in
real
terms)
by
around
this
amount
every
year.
It
is
safe
to
assume
that
activated
carbon
prices
will
decrease
by
at
least
2­
3
percent
in
real
terms
(
net
inflation).
The
most
likely
scenario
is
that
prices
for
sorbents
will
initially
decrease
by
much
more
than
2­
3
percent
as
the
market
for
this
specific
application
grows
and
will
reach
a
steady
state
annual
reduction
of
2­
3
percent.

The
final
decrease
in
costs
will
come
about
through
innovative
equipment/
technology
configurations
such
as
the
EPRI
TOXECON
II.
Currently,
EPA
modeling
includes
the
cost
for
the
loss
of
sale
of
power
plant
fly
ash
plus
landfill
costs
to
dispose
of
the
fly
ash.
The
EPRI
TOXECON
II
process
eliminates
the
cost
of
loss
of
sale
of
the
fly
ash
for
concrete
without
the
need
for
a
new
fabric
filter.
As
a
result,
plants
will
be
able
to
avoid
one
of
the
most
costly
aspects
of
the
technology.
As
shown
in
Table
1,
the
capital
cost
of
installing
a
COHPAC
fabric
filter
is
expected
to
range
between
$
15
­
50/
kW
depending
on
the
plant
configuration.
Also
given
in
Table
1,
the
capital
cost
of
installation
ACI
systems
is
expected
to
range
between
$
1.5­
3/
kW.

When
considering
the
combination
of
the
decrease
in
cost
of
sorbent
technologies
with
time
due
to
equipment/
technology
innovation,
improvements
in
sorbent
removal
efficiencies,
and
the
reduction
in
sorbent
production
costs;
it
is
safe
to
assume
that
costs
for
this
technology
will
decrease
over
time.
A
more
likely
scenario
for
costs
of
ACI
over
the
next
three
to
five
years
would
be
more
significant
reductions
in
overall
costs
by
a
factor
of
2
or
more
compared
to
current
EPA
and
DOE
projections
of
only
2.5
percent.

The
ECO
process
is
currently
being
commercially
demonstrated
in
a
50­
MW
slipstream
unit
at
First
Energy
Corporation's
R.
E.
Burger
Plant
in
Shadyside,
Ohio.
The
unit
processes
flue
gas
from
a
plant
burning
eastern
bituminous
coal.
As
of
August
2004,
ECO
performance
has
met
or
exceeded
most
commercial
objectives.
Mercury
removal
across
the
ECO
system
has
ranged
from
75­
85
percent
with
total
inlet
Hg
concentration
up
to
16

g/
Nm3.
SO
2
removal
is
routinely
greater
than
99
percent
with
inlet
SO
2
concentrations
up
to
2200
ppm
and
outlet
concentrations
below
10
ppm.
NO
x
removal
has
been
as
high
as
82
percent
with
outlet
levels
of
0.05
lb/
MMBtu.
9­
39
Prior
to
proceeding
with
the
50­
MW
commercial
demonstration
unit,
Powerspan
conducted
pilot
testing
in
a
I­
MW
slipstream
unit
at
the
R.
E.
Burger
Plant.
During
approximately
18
months
of
testing,
the
plant
burned
a
blend
of
bituminous
and
subbituminous
coals.
Typical
values
for
Hg
concentration,
chlorine,
and
sulfur
content
in
the
coal
were
0.09
ppm
Hg,
0.06
percent
chlorine,
and
1.9
percent
sulfur.
Ontario­
Hydro
sampling
was
conducted
by
Air
Compliance
Testing
(
Cleveland,
Ohio)
at
the
ECO
pilot
unit
in
May
2002.
Ontario
Hydro
testing
measures
gas­
phase
Hg
(
elemental
and
oxidized
forms)
and
Hg
bound
to
particulate
matter
in
the
flue
gas.
Air
Compliance's
testing
consisted
of
three
sample
runs
each
on
the
inlet
and
outlet
flue
gas
streams.
Two
of
the
three
sets
of
sample
runs
had
sample
durations
in
each
location
of
four
hours
while
sampling
for
the
remaining
set
of
runs
lasted
three
hours
in
each
location.
The
Hg
removal
for
particulate,
oxidized,
and
elemental
are
provided
in
Table
2
with
the
overall
Hg
removal
measured
at
88
percent.

Table
2.
Mercury
Removal
at
ECO
Pilot
Demonstration
Hg
Fraction
ECO
Inlet
ECO
Outlet
%
Removal
Particle
Bound
Hg
(

g/
dscm)
0.62
0.016
97.4
Oxidized
Hg
(

g/
dscm)
5.81
0.022
99.6
Elemental
Hg
(

g/
dscm)
0.16
0.75
Total
Hg
(

g/
dscm)
6.59
0.79
88.0
Table
2
provides
estimates
of
the
ECO
process
performance
for
various
plant
configurations.
It
is
expected
that
80
percent
Hg
removal
across
the
ECO
system
will
be
achieved
with
the
application
of
the
ECO
process
for
units
burning
bituminous
coals.
The
average
incremental
removal
for
fabric
filter
and
hot­
side
ESP
applications
are
expected
to
be
similar
to
that
demonstrated
at
the
ECO
commercial
demonstration
unit
at
the
R.
E.
Burger
Plant,
which
employs
a
cold­
side
ESP.
The
cost
and
performance
estimates
are
based
on
results
currently
being
commercially
demonstrated
in
a
50­
MW
slipstream
unit
at
First
Energy
Corp.'
s
R.
E.
Burger
Plant.

Table
2.
Mercury
Removal
Capacity
of
ECO
Commercial
Technology
Plant
Configuration
Coal
Type
%
Reduction
Cost
Year
Commercially
Available
Min
Max
Avg.
Totala
Avg.
Increm.
b
Capital
($/
kW)
O&
M
($/
kW
h)
%
Expected
Change
Cost
±
w/
timec
CESPd
Bit
f
f
f
80
225
0.0027
Decrease
2006
FF
Bit
80
225
0.0027
Decease
2006
HESPe
Bit
80
225
0.0027
Decrease
2006
a
This
is
the
percent
reduction
attributable
to
the
existing
pollution
controls
and
the
technology.
b
This
is
the
percent
reduction
attributable
only
to
the
technology.
9­
40
c
In
EPA's
modeling,
is
it
appropriate
for
an
economic
forecast
to
assume
an
improvement
in
costs
over
time
(
such
as
through
technology
cost
reductions
or
through
future
technology
innovation).
d
CESP­
represents
cold­
side
electrostatic
precipitator
e
HESP­
represents
hot­
side
electrostatic
precipitator
f
Measurements
of
the
Hg
content
in
the
coal
and
in
the
flue
gas
upstream
of
the
plant's
ESP
have
not
been
made.

The
ECO
process
is
currently
being
commercially
demonstrated
in
a
50­
MW
slipstream
unit
at
First
Energy
Corporation's
R.
E.
Burger
Plant
in
Shadyside,
Ohio.
Previously,
ECO
was
pilot
tested
in
a
1­
MW
slipstream
unit
at
the
same
plant.
Commercial
demonstration
testing
is
planned
to
complete
in
the
first
quarter
of
2005.
Based
on
this
project,
Powerspan
will
offer
commercial
ECO
systems
with
industry
standard
guarantees
and
warranties
by
the
beginning
of
2006.

It
is
estimated
that
the
capital
cost
of
the
multipollutant
ECO
process
will
be
$
225/
kW
and
the
operation
and
maintenance
costs
will
be
$
0.0027/
kWh.
These
are
the
estimated
costs
for
cold­
side
ESP
application
based
on
the
experience
at
the
Burger
Plant.
The
cost
for
fabric
filter
and
hot­
side
ESP
applications
are
expected
to
be
similar
to
cold­
side
ESP
application.
To
estimate
the
cost
effectiveness
of
the
process
for
Hg
removal,
it
is
estimated
that
the
variable
cost
of
Hg
removal
in
the
ECO
process
is
$
800
per
pound
of
Hg,
including
the
sorbent
media
and
its
disposal.
The
costs
are
expected
to
decrease
over
time
due
to
technology
innovations;
however,
the
level
of
cost
reduction
has
not
yet
been
estimated.

Since
the
K­
Fuel
process
reduces
emissions
of
multiple
pollutants,
coal­
fired
facilities
that
will
most
benefit
from
burning
K­
Fuel
to
reduce
Hg
emissions
include
those
units
that
will
achieve
the
most
co­
benefit
from
SO
2
and
NO
x
emission
reductions
as
well
as
heat
rate
improvements.
K­
Fuel
will
benefit
units
burning
high
sulfur
bituminous
coal
with
no
SO
2
control,
units
burning
declining
supplies
of
Central
Appalachian
SO
2
compliant
coal,
units
that
have
switched
from
bituminous
to
subbituminous
coal
to
meet
the
Title
IV
Acid
Rain
requirements
with
a
resulting
loss
in
generating
capacity,
units
with
no
post­
combustion
SO
2
or
NO
x
control,
and
small
generating
units
that
are
searching
for
low
capital
cost
Hg
control.
K­
Fuel
can
also
be
burned
in
units
currently
burning
subbitminous
coal
and
lignite,
the
feedstocks
for
K­
Fuel.

K­
Fuel
is
a
commercially
viable
pre­
combustion
solution
and
proven
technology
for
western
coal
to
reduce
Hg
emissions
from
coal­
fired
power
plants.
K­
Fuel
accomplishes
Hg
reduction
through
its
coal
beneficiation
process.
In
effect,
by
combusting
K­
Fuel
the
utility
is
achieving
Hg
reduction
for
free
since
Hg
removal
has
already
occurred
during
the
K­
Fuel
process
prior
to
combustion
by
a
utility.

Table
4
below
provides
laboratory
data
for
various
feedstocks
of
sub
bituminous
coal,
along
with
the
corresponding
reduction
in
Hg,
increase
in
heat
rate
(
Btu),
and
reduction
in
moisture
content
achieved
by
the
K­
Fuel
process.
The
information
presented
demonstrates
that
the
effectiveness
of
the
process
is
dependent
upon
the
properties
of
the
unique
coal
feedstock.

To
date,
the
K­
Fuel
pre­
combustion
process
has
not
been
optimized
for
Hg
emission
reduction
but
is
a
co­
benefit
of
the
pre­
combustion
process.
In
Table
4,
the
amount
of
Hg
9­
41
removal
listed
is
the
amount
of
Hg
reduced
in
the
coal
prior
to
combustion
and
does
not
consider
the
potential
additional
reductions
from
existing
control
technologies
(
e.
g.,
electrostatic
precipitators,
fabric
filters,
etc.).
As
a
result,
the
Hg
reduction
numbers
below
are
a
beginning
point
for
the
ultimate
Hg
reduction
achievable
when
burning
K­
Fuel,
not
accounting
for
plant
specific
characteristics.

A
facility
knows
when
it
purchases
K­
Fuel
how
much
Hg
has
already
been
removed
and
what
amount
of
Hg
is
in
the
K­
Fuel
prior
to
combustion.
Additional
Hg
removal
above
that
already
achieved
in
the
K­
Fuel
will
be
dependent
upon
unit
specific
characteristics
such
as
installed
pollution
control
devices
and
boiler
characteristics,
as
mentioned
below.

Table
4.
Emissions
Reductions
from
Laboratory
Tests
using
F­
Fuel
Process
Coala
ID
Coal
As
Rec.
Moistur
e
Percent
Coal
As
Rec.
Btu/
Lb
Coal
As
Rec.
Hg
lbs/
TBt
u
K­
Fuel
As
Rec.
Moistur
e
Percent
K­
Fuel
As
Rec.
Btu/
Lb
K­
Fuel
Hg
lbs/
TBt
u
Moistur
e
Remova
l
Percent
Btu
Increase
Percent
Total
Mercur
y
Remova
l
Percent
Coal
1
31.06
8520
1.98
6.06
11667
0.63
80
37
68
Coal
2
27.00
8969
24.17
5.74
11683
3.75
79
30
85
Coal
3
28.41
8536
12.58
6.46
11331
3.10
77
33
75
Coal
4
32.04
7903
7.99
7.06
11162
1.84
78
41
77
Coal
5
31.72
8126
6.30
8.00
11091
2.30
75
37
63
Coal
6
30.93
8235
3.51
6.91
11149
2.02
78
35
42
Coal
7
31.20
8032
4.05
7.09
10535
1.93
77
31
52
a
Subbituminous
coals
were
used
for
all
of
the
laboratory
tests.

K­
Fuel
does
not
impose
any
installation,
capital,
or
operating
costs
in
addition
to
the
cost
of
K­
Fuel
per
ton
to
achieve
Hg
reduction
since
Hg
reduction
is
already
achieved
in
K­
Fuel
prior
to
combustion
in
a
coal­
fired
unit.
As
a
solid
coal
fuel,
K­
Fuel
will
not
negatively
impact
system
components
or
byproducts
since
there
are
no
chemicals,
additives,
or
other
substances
added
to
the
combustion
process,
flue
gas,
or
to
the
K­
Fuel
itself
to
enhance
Hg
removal
Currently,
KFx
conservatively
estimates
that
K­
Fuel
will
be
sold
for
$
33
per
ton
(
including
transportation
costs),
though
market
conditions
and
other
factors
may
impact
the
price.

In
June
2004,
KFx
announced
its
purchase
of
the
Fort
Union
mine
site
near
Gillette,
Wyoming
as
the
location
for
a
commercial
K­
Fuel
production
facility.
The
site
includes
approximately
1,000
acres
of
land,
a
rail
loop
with
load
out
facilities,
a
coal
crusher,
related
buildings,
water
disposal
wells
and
about
500,000
tons
of
remaining
coal
reserves.
Private
money
is
fully
funding
the
project
and
the
Wyoming
Department
of
Environmental
Quality
(
WYDEQ)
has
finalized
all
permits
necessary
for
construction.
The
final
air
quality
permit
was
granted
from
WYDEQ
on
November
8,
2004
and
ground
was
broken
on
the
site
November
10,
2004.
Concrete
foundations
have
begun
being
poured
as
of
December
2004.
Fabrication
of
the
major
9­
42
process
components
of
the
facility
is
near
completion.

The
feedstock
coal
to
produce
K­
Fuel
will
be
purchased
from
adjacent
mines
in
the
Powder
River
Basin.
Initial
output
from
the
facility
will
be
750,000
tons
per
year
and
two­
thirds
of
the
output
has
been
pre­
sold
with
the
remaining
portion
to
be
used
for
test
burns
to
facilitate
additional
markets
for
K­
Fuel.
The
K­
Fuel
production
facility
is
expected
to
be
in
commercial
operation
in
the
summer
of
2005.
The
facility
can
be
expanded
to
produce
up
to
8
million
tons
per
year
of
K­
Fuel
and
KFx
expects
that
with
the
first
commercial
plant
in
operation
the
development
of
future
plants
will
be
accelerated.
KFx
is
examining
potential
commercial
sites
in
Wyoming,
Alaska,
South
Dakota,
and
other
locations
for
additional
K­
Fuel
production
facilities.
KFx
plans
to
own
and
operate
the
K­
Fuel
production
facilities,
as
well
as
license
K­
Fuel
technology
to
third
parties
in
the
U.
S.
and
internationally.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5472)
noted
that
its
commitment
to
environmental
stewardship
led
it
to
participate
as
a
partner
with
Sorbent
Technologies
Corporation
and
others
in
a
U.
S.
Department
of
Energy
(
DOE)
co­
funded
project
to
test
an
advanced
halogenated
activated
carbon.
The
test
objective
was
to
determine
the
Hg
removal
performance
and
relative
costs
of
sorbent
injection
for
advanced
sorbent
materials
in
a
large­
scale
field
trial.
One
of
the
sites
tested
was
the
commenter's
St.
Clair
Power
Plant
Unit
1
(
STCPP
U1)
with
a
cold­
side
electrostatic
precipitator
(
ESP)
using
subbituminous
coal,
or
a
blend
of
subbituminous
and
bituminous
coal.
STCPP
U1
is
nominally
150
MW,
but
a
completely
split
duct
configuration
allows
testing
to
be
completed
on
half
of
the
flue
gas
stream,
without
resorting
to
the
uncertainty
of
slipstream
configurations.

The
commenter
offered
STCPP
U1
to
testing
for
several
reasons.
The
majority
of
Hg­
related
testing
done
previously
was
completed
on
units
burning
either
bituminous,
subbituminous,
or
lignite
coals.
Since
most
of
the
commenter's
units
burn
a
blend
of
bituminous
and
subbituminous
coals,
it
was
interested
in
improving
the
understanding
of
the
effect
of
these
blends
on
the
ability
to
control
Hg
emissions.
STCPP
U1
an
effectively
burn
100
percent
subbituminous
and
blends
up
to
70
percent
subbituminous
and
30
percent
bituminous.
This
unit
could
provide
the
opportunity
to
test
either
100
percent
subbituminous
or
the
blended
fuel.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
9­
43
Comment:

One
commenter
(
OAR­
2002­
0056­
5472)
was
concerned
about
the
ability
of
normal
sized
ESPs
to
remove
the
additional
particulate
loading
resulting
from
injection
of
sorbents.
STCPP
U1
is
equipped
with
a
700
SCA
(
specific
collection
area)
ESP,
which
is
about
three
times
larger
than
the
average
sized
ESP.
Not
knowing
how
much
sorbent
would
be
injected
or
the
ability
of
the
ESP
to
remove
particulate
under
the
injection
conditions,
this
unit's
ESP
could
be
expected
to
handle
any
possible
additional
loading.
This
means
that
particulate
removal
would
not
be
expected
to
limit
testing
for
Hg
removal
even
at
higher
injection
rates.

In
addition,
the
commenter
believed
that
this
testing
opportunity
would
provide
some
insight
into
the
balance­
of­
plant
impacts
it
might
expect
if
using
sorbent
injection
as
an
emission
control
technology
at
this
or
other
coal­
fired
boilers.

Baseline
testing
and
parametric
testing
demonstrated
that
B*
PACTM
could
be
expected
to
provide
the
best
results
of
the
sorbents
tested,
even
at
a
lower
injection
rate
of
3
lbs/
Macf.
The
final
step
of
this
test
was
to
inject
B*
PAC
at
3
lbs/
Macf
for
a
30­
day
period,
while
the
boiler
operated
under
normal
(
varying)
load
conditions.
Over
the
30­
day
test
period,
the
sorbent
injection
equipment
constructed
for
the
test
was
able
to
adequately
follow
the
boiler
load
swings
and
maintain
a
consistent
injection
rate.
The
Hg
removal
rate
averaged
93
percent
over
the
30
day
period.
The
commenter
reported
that
these
promising
results
encourage
additional
testing
for
longer
duration
under
more
challenging
conditions.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5472)
noted
that
longer
testing
periods
(
minimally
one
year)
are
required
to
hopefully
identify
any
unintended
and
unanticipated
consequences
resulting
from
the
operation
of
this
and
other
technologies.
Cumulative
effects
on
collection
equipment
or
other
downstream
equipment
not
identified
in
a
30­
day
test
could
be
identified
after
longer
term
operation,
as
has
been
experienced
with
other
control
technologies.
Identification
of
an
unanticipated
consequence
after
a
commitment
to
a
particular
technology
puts
the
electric
supply
at
risk.
The
commenter
believes
that
this
is
an
unacceptable
result
of
rushing
a
little­
tested
technology
into
operation.
A
technology
must
be
tested
under
various
fuels
and
operating
conditions
to
validate
commercial
viability.
One
30­
day
test
cannot
provide
the
operational
assurances
necessary
to
ensure
the
performance
and
reliability
required
of
electric
generating
units.

The
commenter
reported
that
the
particulate
control
equipment
was
never
expected
to
be
a
challenge
or
represent
a
normal
operation
during
this
test.
This
unit
was
chosen,
in
part,
because
of
an
equipment
configuration
that
would
eliminate
particulate
collection
as
a
concern.
9­
44
The
ESPs
on
STCPP
U1,
however,
approach
3
times
the
collection
capability
of
a
normal
electric
generating
unit
ESP.
Additional
testing
is
required
to
demonstrate
what
operational
impacts
might
be
expected
on
smaller
ESPs
(<
250
SCA)
and
what
equipment
and
operational
modifications
might
be
required
for
long­
term
operation
of
sorbent
injection
technologies.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5472)
reported
that
much
of
the
industry's
fly
ash
is
currently
used
productively
for
commercial
uses.
The
B­
PAC
sorbent
used
in
this
test
makes
fly
ash
unusable
as
a
concrete
additive,
which
necessitates
landfi1l
disposal
of
a
previously
useful
byproduct.
There
is
a
need
to
develop
and
then
conduct
similar
tests
with
"
concrete­
friendly"
sorbents
which
will
keep
these
productive
uses
for
fly
ash
viable.

Because
of
the
short­
term
nature
of
this
test,
there
is
a
still
need
to
further
investigate
equipment
risks,
such
as
potential
corrosion
in
ductwork
and
gas
handling
equipment
and
the
possibility
of
contamination
issues
in
areas
of
fly
ash
hideout.

The
ultimate
fate
of
halogens,
including
bromine,
in
the
flue
gas
stream
is
a
continuing
area
of
concern.
Any
concerns
about
the
possible
formation
of
toxic
byproducts
in
flue
gas
stream
must
be
thoroughly
investigated
and
dispelled
before
this
technology
can
be
widely
deployed.
There
have
only
been
preliminary
tests
conducted
in
coal­
fired
electric
generating
boiler
flue
gas
streams,
and
this
issue
requires
significantly
further
research.

In
addition
to
these
specific
comments
offered
related
to
the
company's
experience
testing
Brominated
activated
carbon
injection,
the
commenter
also
supports
the
comments
submitted
by
the
Edison
Electric
Institute
(
EEI),
the
Utility
Air
Regulated
Group
(
UARG),
and
the
Electric
Power
Research
Institute
(
EPRI).

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5496)
is
an
advocate
of
public
policies
that
are
protective
of
public
health
and
is
prepared
to
make
reasonable
additional
reductions
in
power
plant
Hg
emissions.
This
commenter
has
been
a
strong
advocate
for
the
Minnesota
Mercury
9­
45
Contamination
Reduction
Initiative
and
achieved
about
17
percent
reduction
in
Hg
stack
emissions
in
2000
compared
to
1990
levels
through
optimizing
fuel
sourcing
and
plant
operation.
The
commenter's
coal
units
are
also
over
70
percent
wet
scrubbed
for
particulate
and
sulfur
dioxide
removal,
which
combined
with
other
voluntary
Hg
reduction
activities
has
reduced
base
line
emissions
relative
to
1990
and
compared
to
other
utility
units.
Consequently,
an
equitable
allocation
of
Hg
reduction
requirement
stringency,
either
through
unit
specific
requirements
or
cap­
and­
trade
program
allowance
allocation
methodology
is
important
for
assuring
reasonable
credit
for
early
action.
The
commenter
supports
an
equitable
cap­
and­
trade
approach
as
the
preferred
option
for
regulating
electric
power
sector
Hg
emissions,
as
that
provides
the
most
flexibility
for
achieving
compliance
using
new
and
often
unproven
technology.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
See
final
rule
preamble
for
rationale.

Comment:

One
commenter
(
OAR­
2002­
0056­
5496)
notes
that
the
technology
EPA
and
other
modelers
have
presumed
to
be
effective
for
achieving
high
percentages
of
Hg
removal
in
their
Integrated
Planning
Model
involves
use
of
activated
carbon
injection
followed
by
particulate
collection.
However,
over
70
percent
of
this
commenter's
coal
generation
is
operated
with
wet
scrubbers,
providing
for
particulate
removal
while
delivering
sulfur
dioxide
emission
reductions.
The
commenter
has
injected
activated
carbon
into
its
wet
scrubbers
and
found
only
small
improvements
in
Hg
removal
(
zero
to
30
percent)
over
the
realm
of
typical
activated
carbon
injection
rates.
The
wet
scrubbers
create
a
near­
saturated
flue
gas
with
entrained
water
droplets,
making
operation
with
a
fabric
filter
downstream
of
the
scrubber
impractical
due
to
filter
plugging.
The
flue
gas
temperature
upstream
of
the
wet
scrubbers
is
too
high
for
reliable
filter
operation.
Consequently,
units
operating
with
existing
wet
scrubbers
are
not
amenable
to
retrofit
of
activated
carbon
and
fabric
filter
technology.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
See
final
rule
preamble
for
rationale.
Under
a
cap­
and­
trade
approach
the
commenter
will
have
flexibility
in
its
compliance
options
including
buying
allowances.
EPA
also
notes
that
ACI
with
a
pulse­
jet
fabric
may
be
installed
upstream
of
wet
scrubber.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5496)
notes
that
IPM
modeling
presumes
uniform
control
costs
and
percent
Hg
reductions
for
coal
units
that
are
targeted
to
retrofit
activated
carbon
injection
and
fabric
filters,
without
sufficient
consideration
of
unit
size
(
economy
of
scale),
coal
type
(
concentration
and
species
of
Hg
emitted)
or
current
emission
rates.
Incremental
9­
46
reductions
in
the
targeted
Hg
emissions
cap
should
be
expected
to
give
increasingly
higher
Hg
reduction
costs
in
terms
of
dollars
per
pound
Hg
removal
when
performing
modeling.
For
example,
the
Table
1
 
Summary
of
CCAP
Power
Sector
Modeling
(
Federal
Register
Volume
69
No
230
page
69868)
presents
a
linear
incremental
cost
as
the
Hg
cap
is
reduced
from
15
tons
to
7.5
tons
over
a
regime
of
affected
units
that
would
be
expected
to
exhibit
higher
costs
due
to
economy
of
scale
or
lower
Hg
content
coal.
Linear
consideration
of
unit
control
retrofit
costs
affirms
the
IPM
does
not
adequately
address
incremental
control
costs.

Response:

The
commenter
is
incorrect
that
IPM
modeling
uses
uniform
control
costs
and
percent
Hg
reductions.
Hg­
specific
control
costs
(
ACI)
vary
by
size
of
the
unit
and
coal
type
burned.
Hg
removal
varies
by
coal
type
and
control
type.
In
addition
scrubbers
and
SCR
also
consider
economies
of
scale.
See
IPM
documentation
in
docket
for
further
discussion
of
control
cost
and
performance
assumptions.

Comment:

One
commenter
(
OAR­
2002­
0056­
5561)
stated
that
the
demand
growth
assumptions
used
in
our
sensitivity
analyses,
published
in
the
NODA,
appeared
to
be
reasonable.
The
average
growth
rate
of
1.8
percent
per
year
was
identical
to
the
latest
demand
forecast
published
in
Energy
Information
Administration's
2005
Annual
Energy
Outlook.
Demand
forecasts
used
by
other
analysts
such
as
Cinergy
(
2.3
percent
per
year)
may
be
too
high.
The
natural
gas
price
assumptions
used
in
the
commenter's
sensitivity
analyses,
on
the
other
hand,
may
be
somewhat
low.
Use
of
higher
gas
price
assumptions
would
be
expected
to
raise
system
costs
in
both
the
base
and
policy
cases.
It
was
not
clear
what
effect
higher
gas
prices
would
have
on
the
incremental
cost
of
the
various
Hg
policy
scenarios
that
were
investigated.
However,
the
sensitivity
runs
the
commenter
evaluated
with
higher
gas
prices
and
load
growth
assumptions
resulted
in
very
modest
increases
in
system
costs
(
roughly
1
percent)
for
the
increasingly
tighter
second
Phase
Hg
caps
over
the
system
cost
increases
under
increasingly
stringent
scenarios
using
our
original
lower
gas
price
and
load
growth
assumptions.
(
See
Document
ID
No.
OAR­
2002­
0056­
xxxx
submitted
on
June
29,
2004
for
details
on
the
Air
Quality
Dialogue
analyses.)

Response:

As
discussed
in
EPA's
IPM
documentation,
EPA
uses
its
natural
gas
prices
and
demand
forecasts
different
from
those
of
EIA.
EPA
has
performed
a
sensitivity
analysis
examining
the
impact
of
uses
EIA
natural
gas
prices
and
electric
growth
projections.
See
chapter
7
of
final
rule
CAMR
RIA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5521)
provided
the
following
information:

Limestone
Forced
Oxidation
(
LFSO)
9­
47
This
cost
estimate
was
for
the
cost
of
installing,
operating,
and
maintaining
LFSO
only.

Merrimack
Station
Cost
Estimate
(
1995
Dollars)
MK
1
(
113
MWe)
MK2
(
320
MWe)

Capital
$
48/
kW
($
54,240,000)*
$
250/
kW
($
80,000,000)*
Fixed
O&
M
$
16.0/
kW/
yr
($
1,808,000/
yr)
$
10.0/
kW­
yr
($
3,200,000/
yr)
Variable
O&
M
1.1
mills/
kWh
(
$
868,733/
yr)
1.1
mills/
kWh
($
2,527,360/
yr)
Total
Annual**
10.26
mills/
kWh
($
8,100,733/
yr)
5.98
mills/
kWh
($
13,727,360/
yr)
*
This
capital
cost
estimate
included
the
costs
for
a
reagent
feed
system,
a
wet
SO2
removal
system,
a
flue
gas
handling
system,
a
waste/
by­
product
handling
system
and
support
equipment
(
exhaust
stack)
but
didn't
include
a
cost
estimate
for
replacement
of
primary
fans
if
required.
**
Used
2002
MWh
to
estimate
cost
in
mills/
kWh.

Powdered
Activated
Carbon
Injection
This
cost
estimate
was
for
the
cost
of
installing,
operating,
and
maintaining
the
Powdered
Activated
Carbon
Injection
only.
Costs
were
calculated
using
U.
S.
EPA's
and
U.
S.
DOE's
Mercury
Control
Performance
and
Cost
Model
(
MCPCM),
September
30,
2000.

Merrimack
Station
Cost
Estimate
(
1999
Dollars)
MK
1
(
113
MWe)
MK2
(
320
MWe)

Capital
$
8.49/
kW***
($
959,370)
$
5.97/
kW***
($
1,910,400)

Fixed
O&
M
$
3.64/
kW/
yr
($
411,320/
yr)
$
1.64/
kW/
yr
($
524,800/
yr)

Variable
O&
M
1.10
mills/
kWh
($
868,733/
yr)
1.10
mills/
kWh
($
2,527,360/
yr)

Total
Annual**
1.74
mills/
kWh
($
1,375,990/
yr)
1.41
mills/
kWh
($
3,243,200/
yr)

**
Used
2002
MWh
to
estimate
cost
in
mills/
kWh.
***
Total
Control
Capital
Costs
including
process
equipment,
field
materials,
field
labor,
indirect
field
costs,
engineering
and
home
office
overhead/
fees,
process
contingency,
project
contingency,
and
general
facilities.

Powdered
Activated
Carbon
Injection
&
Spray
Cooling
This
cost
estimate
was
for
the
cost
of
installing,
operating,
and
maintaining
the
Powdered
Activated
Carbon
Injection
and
Spray
Cooling
system
only.
Costs
were
calculated
using
U.
S.
EPA's
and
U.
S.
DOE's
Mercury
Control
Performance
and
Cost
Model
(
MCPCM),
September
9­
48
30,2000.

Merrimack
Station
Cost
Estimate
(
1999
Dollars)
MK
1
(
113
Mwe)
MK2
(
320
MWe)

Capital
$
24.63/
kW***($
2,783,190)
$
17.20/
kW***($
5,504,000)

Fixed
O&
M
$
5.58/
kW/
yr
($
630,540/
yr)
$
2.99/
kW/
yr
($
956,800/
yr)

Variable
O&
M
1.13
mills/
kWh
($
900,323/
yr)
1.14
mills/
kWh
($
2,619,264/
yr)

Total
Annual**
2.29
mills/
kWh
($
1,809,182/
yr)
1.80
mills/
kWh
($
4,126,464/
yr)

**
Used
2002
MWh
to
estimate
cost
in
mills/
kWh.
***
Total
Control
Capital
Costs
including
process
equipment,
field
materials,
field
labor,
indirect
field
costs,
engineering
and
home
office
overhead/
fees,
process
contingency,
project
contingency,
and
general
facilities.

Powdered
Activated
Carbon
Injection
&
Pulse
Jet
Fabric
Filter
This
cost
estimate
is
for
the
cost
of
installing,
operating,
and
maintaining
the
Powdered
Activated
Carbon
Injection,
and
Pulse
Jet
Fabric
Filter
system
only.
Costs
were
calculated
using
U.
S.
EPA's
and
U.
S.
DOE's
Mercury
Control
Performance
and
Cost
Model
(
MCPCM),
September
30,
2000.

Merrimack
Station
Cost
Estimate
(
1999
Dollars)
MK
1
(
113
Mwe)
MK2
(
320
MWe)

Capital
$
50.38/
kW***
($
5,692,940)
$
40.00/
kW***
($
12,800,000)

Fixed
O&
M
$
8.68/
kW/
yr
($
980,840/
yr)
$
5.73/
kW/
yr
($
1,833,600/
yr)

Variable
O&
M
1.15
mills/
kWh
($
908,221/
yr)
1.15
mills/
kWh
($
2,642,240/
yr)

Total
Annual**
3.11
mills/
kWh
($
2,458,355/
yr)
2.51
mills/
kWh
($
5,755,840/
yr)

**
Used
2002
MWh
to
estimate
cost
in
mills/
kWh.
***
Total
Control
Capital
Costs
including
process
equipment,
field
materials,
field
labor,
indirect
field
costs,
engineering
and
home
office
overhead/
fees,
process
contingency,
project
contingency,
and
general
facilities.

Powdered
Activated
Carbon
Injection,
Spray
Cooling
&
Pulse
Jet
Fabric
Filter
9­
49
This
cost
estimate
was
for
the
cost
of
installing,
operating,
and
maintaining
the
Powdered
Activated
Carbon
Injection,
Spray
Cooling,
and
Pulse
Jet
Fabric
Filter
system
only.
Costs
were
calculated
using
U.
S.
EPA's
and
U.
S.
DOE's
Mercury
Control
Performance
and
Cost
Model
(
MCPCM),
September
30,
2000.

Merrimack
Station
Cost
Estimate
(
1999
Dollars)
MK
1
(
113
Mwe)
MK2
(
320
MWe)

Capital
$
66.53/
kW***
($
7,517,850)
$
51.23/
kW***
($
16,393,600)

Fixed
O&
M
$
10.62/
kW/
yr
($
1,200,060/
yr)
$
7.08/
kW/
yr
($
2,265,600/
yr)

Variable
O&
M
1.19
mills/
kWh
($
939,811/
yr)
1.19
mills/
kWh
($
2,734,144/
yr)

Total
Annual**
3.66
mills/
kWh
($
2,891,660/
yr)
2.89
mills/
kWh
($
6,639,104/
yr)

**
Used
2002
MWh
to
estimate
cost
in
mills/
kWh.
***
Total
Control
Capital
Costs
including
process
equipment,
field
materials,
field
labor,
indirect
field
costs,
engineering
&
home
office
overhead/
fees,
process
contingency,
project
contingency,
and
general
facilities.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5456)
noted
that
the
DOE
National
Environmental
Technology
Laboratory
(
NETL)
recently
issued
their
next
round
of
awards
for
testing
of
advanced
Hg
reduction
technologies
at
coal­
fired
power
plants.
This
testing
is
to
take
place
in
the
2005­
2007
time
frame.
The
point
of
this
discussion
is
to
note
that
scientific
testing
and
research
on
Hg
monitoring
and
control
equipment
are
still
continuing
and
will
continue
for
the
next
few
years.
If
the
technologies
related
to
Hg
issues
were
sufficiently
demonstrated,
there
would
be
no
need
for
continuation
of
the
testing
programs
of
this
nature.

The
commenter
has
been
participating
in
various
Hg
projects
that
attempt
to
present
a
better
understanding
of
various
issues
related
to
Hg
emissions
from
the
combustion
of
coal
in
electric
utility
steam
generating
units,
specifically
those
burning
PRB
subbituminous
coal.
These
projects
involve
studying
Hg
emissions
control
technologies
and
Hg
emissions
monitoring.
9­
50
The
DOE/
NETL
announcement
of
the
awards
states
"
With
an
eye
on
future
federal
regulations
aimed
at
reducing
Hg
emissions,
the
DOE
has
selected
six
additional
projects
as
part
of
a
DOE
research
program
to
advance
the
technical
readiness
of
Hg
control
options
for
the
Nation's
fleet
of
coal­
fired
power
plants.
The
six
projects
in
this
next
round
of
awards
build
on
last
year's
selection
of
eight
projects,
and
will
verify
technology
performance,
evaluate
costs,
and
assess
balance­
of
plant
impacts.
The
projects
will
field
test
advanced,
post­
combustion
technologies
involving
all
coal
types
at
utilities
using
pulverized
coal
or
cyclone­
boiler
configurations,
and
focus
on
technologies
capable
of
removing
Hg
from
flue
gas
containing
higher
concentrations
of
elemental
Hg.
The
technologies
include
sorbent
injection,
wet
flue
gas
desulfurization
systems
enhancement,
and
combustion
optimization.
Both
rounds
of
selections
are
aimed
at
meeting
the
Energy
Department's
near­
term
goal
of
having
technologies
that
can
capture
50­
70
percent
of
Hg
emissions
ready
for
commercial
demonstration
by
2005
for
power
plants
burning
bituminous
coal,
and
by
2007
for
those
that
burn
low­
rank
coals
and
blends.
The
Energy
Department
has
set
a
longer
term
goal
of
having
technologies
that
can
achieve
90
percent
Hg
reduction
for
all
fuel
types
ready
for
commercial
demonstration
by
2010,
and
is
also
looking
to
reduce
the
cost
of
Hg
control
by
25­
50
percent
over
baseline,
activated­
carbon
costs,
which
range
from
$
50,000­$
70,000
per
pound
of
mercury
removed."

The
important
statement
in
the
above
is
that
DOE/
NETL
is
seeking
to
be
ready
for
commercial
demonstration,
not
commercial
use,
of
Hg
control
by
2005
for
bituminous
coals,
and
2007
for
low
rank
coals
(
lignite
and
subbituminous
coal).

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
noted
that
in
the
January
Federal
Register
proposal,
EPA
fails
to
acknowledge
the
ongoing
work
being
conducted
under
the
U.
S.
Department
of
Energy/
National
Energy
Technology
Laboratory
(
DOE/
NETL)
Mercury
Control
Technology
Research
Program
on
coal
fired
power
plants.
Four
full­
scale
demonstration
projects
have
tested
the
effectiveness
of
carbon
injection
in
tandem
with
conventional
criteria
air
pollution
control
devices
currently
in
use
at
utilities.
Specifically,
the
E.
C.
Gaston
plant
in
Alabama
burning
low
sulfur
bituminous
coal
achieved
greater
than
a
90
percent
Hg
removal
rate
using
carbon
injection,
along
with
a
hot
side
electrostatic
precipitator
(
ESP)
and
a
compact
hybrid
particulate
collector
(
COHPAC)
baghouse
for
particulate
control.
The
Brayton
Point
plant
in
Massachusetts
burning
low
sulfur
bituminous
coal
achieved
a
90
percent
Hg
removal
rate
using
carbon
injection
in
combination
with
a
cold­
sided
ESP.
The
Pleasant
Prairie
plant
in
Wisconsin
burning
sub­
bituminous
coal
achieved
a
65
percent
removal
rate
using
carbon
injection
with
a
cold­
sided
ESP.
Significantly,
the
E.
C.
Gaston
Plant
achieved
a
high
Hg
removal
rate
and
used
considerably
less
carbon
injection
as
a
result
of
the
addition
of
a
COHPAC
baghouse
or
fabric
filter
in
comparison
to
the
other
projects.
The
additional
pollution
control
equipment
has
the
potential
to
significantly
increase
Hg
removal
rates
from
sources
burning
both
bituminous
and
sub­
bituminous
9­
51
coal.

Real
reductions
for
both
Hg
and
sulfur
can
be
achieved
when
Utility
Units
install
wet
scrubbers
or
spray
dryer
adsorbers,
in
conjunction
with
fabric
filters.
According
to
the
Information
Collection
Request
III
data,
the
lowest
emissions
of
Hg
and
sulfur
were
achieved
when
these
pollution
control
devices
were
used.
The
Department
analyzed
emissions
data
from
Utility
Units
in
eight
states
surrounding
New
York.
This
analysis
showed
that
the
Utility
Units
achieving
the
greatest
Hg
reduction
were
ones
utilizing
fabric
filters.
Several
of
the
better
controlled
units
have
ESPs
but
also
used
a
wet
scrubber
for
sulfur
control.
The
Department
has
experience
with
municipal
waste
combustors
(
MWCs)
in
New
York
that
use
carbon
injection
in
combination
with
fabric
filters
or
ESPs.
These
MWCs
equipped
with
carbon
injection
and
ESPs
achieve
Hg
emissions
reductions
of
at
least
85
percent.
MWCs
equipped
with
carbon
injection
and
fabric
filters
achieve
reductions
greater
than
90
percent.
Mercury
is
predominantly
emitted
in
the
oxidized
form
by
MWCs.

The
Supplemental
Notice
and
a
letter
to
the
Air
Docket
from
the
DOE
(
Document
ID
No.
OAR­
2002­
0056­
0044)
describe
the
need
for
six
years
to
adequately
conduct
a
commercial
demonstration
of
Hg
controls.
The
Department
believes
that
this
long
time
frame
is
not
justifiable
and
it
appears
that
EPA
is
attempting
to
selectively
develop
time
lines
to
justify
a
cap­
and­
trade
program.
Upon
closer
examination,
the
average
six
year
figure
includes
a
pre­
award
period
greater
than
12
months,
with
each
full­
scale
demonstration
project
taking
another
12
months,
and
allows
for
inflation
during
the
operation
and
reporting
time
line
by
including
the
time
it
takes
to
prepare
a
report
on
the
project.
A
more
realistic
value
for
commercial
demonstration
is
in
the
range
of
three
to
four
years,
especially
in
light
of
all
of
the
full­
scale
Hg
demonstration
projects
already
completed
or
currently
being
conducted.

The
goal
of
the
DOE/
NETL
Mercury
Control
Technology
Research
Program
is
for
these
technologies
to
be
available
for
bituminous
sources
by
2005
and
for
lignite
and
sub­
bituminous
sources
by
2007.
The
program
also
describes
the
commercial
development
of
advanced
Hg
control
technology
that
will
achieve
a
90
percent
Hg
reduction
for
all
coal
types
by
2010.
In
fact,
the
field
testing
of
this
technology
at
a
number
of
coal
fired
units
was
already
underway
in
2003.
If
these
goals
are
attained,
widespread
commercial
deployment
of
extremely
efficient
Hg
air
pollution
control
technologies
could
begin
to
occur
in
2008
for
bituminous
sources
and
2011
for
lignite
and
sub­
bituminous
sources.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5446)
believed
that
the
variety
of
input
assumptions,
particularly
in
regard
to
costs
and
Emission
Modification
Factors
(
EMF),
used
in
the
modeling
analysis
highlight
the
uncertainty
associated
with
the
cost
and
performance
of
Hg
control
9­
52
technologies.
Given
the
limited
data
available,
this
uncertainty
is
to
be
expected
and
simply
reflects
limited
knowledge
in
the
area.
Therefore,
any
final
rule
must
be
sufficiently
flexible
to
accommodate
the
high
degree
of
uncertainty
inherent
in
the
available
data.
The
commenter
believed
that
a
national
"
cap
and
trade"
based
regulation
with
appropriate
caps
and
timing
will
provide
an
important
component
of
flexibility
and
will
help
the
EPA
address
this
inherent
uncertainty.

Furthermore
even
the
range
of
assumptions
used
in
the
commentator's
models
only
indicates
that
there
is
uncertainty
in
the
cost
and
performance
of
a
typical
plant
and
typical
coal.
The
models
do
not
account
for
the
wide
variability
of
coals
and
process
conditions
that
can
result
in
significant
differences
in
performance
between
two
plants
with
nominally
similar
coals
and
identical
control
technology.
It
is
important
that
the
EPA
recognize
that
the
performance
of
the
average
plant
does
not
represent
the
behavior
of
the
fleet.
In
order
to
understand
the
implications
of
the
regulation
EPA
must
undertake
some
form
of
probability
analysis
that
considers
natural
variability
in
coal
properties
and
unit
performance
and
assesses
their
impact
on
the
modeled
results.

Failing
to
account
for
variability
in
fuel
type
and
unit
operation
will
make
it
difficult
if
not
impossible
for
EPA
to
establish
limits
that
are
technically
achievable
for
all
affected
units.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
See
final
rule
preamble
for
rationale.
EPA's
IPM
modeling
does
take
into
account
some
extent
variability
of
coals
and
control
configurations.
IPM
provides
for
extensive
modeling
of
the
coal
sector,
where
coals
can
be
selected
by
mercury
content
and
sulfur
content.
For
further
discussion
see
EPA's
IPM
documentation
in
rulemaking
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
was
concerned
that
the
various
input
assumptions
used
in
the
commenters'
modeling
analysis
do
not
account
for
the
wide
variability
of
coals
and
process
conditions
encompassed
by
the
full
fleet
of
US
utility
boilers.
Failing
to
account
for
variability
in
fuel
type
and
unit
operation
will
make
it
difficult
if
not
impossible
for
EPA
to
establish
limits
that
are
technically
achievable
for
affected
units.
The
commenter
suggested,
phased
alternative
to
establishing
a
national
cap
and
trade
program,
as
articulated
in
comments
dated
May
14,
2004,
and
again
in
these
comments
in
response
to
II.
B.
4.
g,
would
address
the
variability
concern
through
ensuring
a
far
better
database
than
currently
exists.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.

Comment:
9­
53
One
commenter
(
OAR­
2002­
0056­
5488)
states
that
activated
carbon
injection
(
ACI)
has
been
extensively
tested
in
several
full­
scale
tests
and
pilot­
scale
tests
and
in
a
recent
long­
term
test
performed
at
the
Gaston
power
plant.
Full
scale
testing
performed
by
ADA­
ES
along
with
testing
performed
by
EPRI
showed
that
high
levels
of
Hg
control,
at
least
90
percent,
could
be
achieved
on
a
cost­
effective
basis
at
coal­
fired
power
plants
with
ACI
regardless
of
the
rank
of
coal
burned,
with
the
utilization
of
modern
particulate
matter
control
equipment
(
i.
e.,
a
fabric
filter
or
a
polishing
baghouse
downstream
of
an
electrostatic
precipitator).
Long­
term
tests
of
ACI
outfitted
with
a
small
baghouse
downstream
of
a
hot­
side
ESP
have
continued
at
the
Gaston
power
plant,
which
burns
bituminous
coal.
This
combination
effectively
addresses
problems
with
carbon­
contamination
of
fly
ash
that
can
occur
when
activated
carbon
injection
is
used
with
an
ESP
alone.
It
is
also
quite
viable
for
retrofit
applications,
because
of
the
compact
size
of
the
polishing
baghouse.
The
tests
conducted
at
Gaston
show
that
such
units
can
achieve
greater
than
90
percent
Hg
control
on
a
long­
term
average
basis,
with
appropriately
sized
baghouses
and
activated
carbon
injection
rates.
The
Gaston
investigators,
from
ADA­
ES,
EPRI
and
DOE,
conclude
that
"
activated
carbon
injection
systems
are
simple,
reliable
and
commercially
available."
The
conclusion
that
activated
carbon
injection
is
commercially
available
today
has
also
been
affirmed
by
the
national
trade
association
of
control
technology
vendors.

Beyond
activated
carbon
injection,
EPA
neglected
to
seriously
consider
several
other
highly
effective
approaches
that
are
available
for
reducing
Hg
emissions
from
existing
coal­
fired
power
plants.
These
include
Electro­
catalytic
oxidationTM,
advanced
dry
FGD,
coal
blending
for
plants
burning
sub­
bituminous
coal,
injection
of
non­
carbon
based
sorbents,
and
pre­
combustion
coal
scrubbing
to
increase
combustion
efficiency
of
lignite
and
sub­
bituminous
coals
while
simultaneously
removing
Hg,
N,
and
S
before
the
coal
is
burned.

Advanced
dry
FGD
technology
is
widely
used
in
Europe
and
has
been
demonstrated
at
Roanoke
Valley
Energy's
55
MW
bituminous
coal
fired
Unit
2
with
Hg
removal
in
excess
of
95
percent.
Two
companies
actively
marketing
advanced
dry
FGD
are
F.
L.
Smidth
AirTech,
which
is
marketing
their
Gas
Suspension
Absorber
(
GSA)
as
a
retrofit
with
an
existing
ESP
or
Pulse
Jet
fabric
filters;
and
RJM­
Beaumont
which
is
marketing
their
Rapid
Absorption
Process
(
RAP)
as
a
multipollutant
(
SO
2,
PM
and
Hg)
control
technology.

Electro­
catalytic
oxidationTM
(
ECO)
technology
has
been
demonstrated
on
a
2000
scfm
pilot
at
First
Energy's
Burger
Plant
in
Akron,
OH,
which
has
been
operating
since
March
2002.
Pilot
test
results
indicate
80­
90
percent
Hg
removal
under
any
inlet
condition.
Early
results
from
a
50
MW
commercial
demonstration
system
at
Burger
indicate
similar
performance
to
the
pilot
tests.
A
510
MW
ECO
system
is
planned
for
installation
at
AmerenUE's
Sioux
Plant
in
Missouri
following
successful
completion
of
the
Burger
demonstration.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:
9­
54
One
commenter
(
OAR­
2002­
0056­
5502)
referenced
technological
improvement.
The
history
of
technology
development,
including
that
of
environmental
controls,
clearly
shows
that
technology
does
improve
with
time.
Examples
(
see
Document
ID
No.
OAR­
2002­
0056­
5502)
are
provided
to
support
a
modest
improvement
rate
of
2.5
percent
per
year,
which
is
one
of
the
several
cases
(
along
with
quicker
and
slower
growth
cases)
modeled
by
Charles
River
Associates
for
the
EEI
and
the
commenter's
submittals
in
June
2004.
Because
technology
improvement
affects
the
control
technology
choices
made
by
power
plants
in
the
model
analysis,
and
therefore
provides
a
more
realistic
prediction
of
the
industry's
likely
response
to
the
various
proposed
regulatory
scenarios,
the
commenter
believed
it
is
important,
and
very
appropriate,
to
include
cost
reductions
and/
or
performance
improvements
in
an
economic
model.

Control
considerations
for
modeling.
The
detailed
comments
provide
information
on
the
topics
identified
in
EPA's
question
(
under
§
II.
B.
4.
c)­
timeline
for
commercialization,
cost,
balance
of
plant
impacts,
and
control
performance.
While
the
commenter
could
not
comment
on
commercialization
issues
as
they
do
not
own
and
operate
power
plants,
they
have
provided
the
conditions
they
believe
are
needed
for
Hg
controls
to
be
considered
"
commercially
available."
These
include
consistent,
predictable
results
from
the
approximately
30
field
tests
sponsored
by
DOE
and
the
co­
funded
by
the
industry
and
the
commenter,
as
well
as
enough
truly
long­
term
tests
(
e.
g.,
12­
18
months)
to
ensure
that
the
industry
understands
how
to
operate
the
equipment
reliably
and
manage
and
plant
impacts
that
may
be
caused
by
the
technology.
A
technology
that
gets
this
far
is
then
ready
to
be
procured
by
the
first
users,
with
full
implementation
by
al
plants
that
select
this
technology
several
years
later.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5505)
stated
that
the
Department
of
Energy
(
DOE)
National
Environmental
Technology
Laboratory
(
NETL)
recently
issued
their
next
round
of
awards
for
testing
of
advanced
Hg
reduction
technologies
at
coal­
fired
power
plants.
This
testing
is
to
take
place
in
the
2005­
2007
time
period.
The
point
of
this
discussion
is
to
note
that
scientific
testing
and
research
on
Hg
control
technologies
are
still
continuing
and
will
continue
to
do
so
now
and
for
the
next
number
of
years.
If
the
technology
were
sufficiently
demonstrated,
there
would
be
no
need
for
continuation
of
the
testing
programs
of
this
nature.

The
DOE/
NETL
announcement
of
the
awards
(
5
November
2004)
states
"
With
an
eye
on
future
federal
regulations
aimed
at
reducing
Hg
emissions,
the
DOE
has
selected
six
additional
projects
as
part
of
a
DOE
research
program
to
advance
the
technical
readiness
of
Hg
control
9­
55
options
for
the
Nation's
fleet
of
coal­
fired
power
plants.

The
six
projects
in
this
second
round
of
awards
build
on
last
year's
selection
of
eight
projects,
and
will
verify
technology
performance,
evaluate
costs,
and
assess
balance­
of
plant
impacts.
The
projects
will
field
test
advanced,
post­
combustion
technologies
involving
all
coal
types
at
utilities
using
pulverized
coal
or
cyclone­
boiler
configurations,
and
focus
on
technologies
capable
of
removing
Hg
from
flue
gas
containing
higher
concentrations
of
elemental
Hg.
The
technologies
include
sorbent
injection,
wet
flue
gas
desulfurization
systems
enhancement,
and
combustion
optimization.

Both
rounds
of
selections
are
aimed
at
meeting
the
Energy
Department's
near­
term
goal
of
having
technologies
that
can
capture
50­
70
percent
of
Hg
emissions
ready
for
commercial
demonstration
by
2005
for
power
plants
burning
bituminous
coal,
and
by
2007
for
those
that
burn
low­
rank
coals
and
blends.
The
Energy
Department
has
set
a
longer
term
goal
of
having
technologies
that
can
achieve
90
percent
Hg
reduction
for
all
fuel
types
ready
for
commercial
demonstration
by
2010,
and
is
also
looking
to
reduce
the
cost
of
Hg
control
by
25­
50
percent
over
baseline,
activated­
carbon
costs,
which
range
from
$
50,000
to
$
70,000
per
pound
of
mercury
removed."

The
important
statement
in
the
above
is
that
DOE/
NETL
is
seeking
to
be
ready
for
commercial
demonstration,
not
commercial
use,
of
Hg
control
by
2005
for
bituminous
coals,
and
2007
for
low
rank
coals
(
lignite
and
subbituminous
coal).

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

The
commenter
(
OAR­
2002­
0056­
5519)
stated
that
information
referred
to
earlier
demonstrated
that
Hg
controls
were
commercially
viable
and
cost
effective:

°
Low
NO
x
burners,
activated
carbon
injection
(
ACI),
selective
catalytic
reduction
(
SCR),
and
acid
gas
controls
[
including
Lime
Stone
Forced
Oxidation
(
LFSO)]
and
wet
Electrostatic
Precipitators
(
wet­
ESPs)
for
reducing
Hg
emissions,
were
already
commercially
available
and
ready
for
installation
on
all
coal­
fired
electric
steam
generating
units
for
all
types
of
coal,
and
°
The
maximum
total
control
costs
for
achieving
90
percent
Hg
removal
efficiency
on
a
100
MW
coal­
fired
electric
steam
generating
unit
was
less
than
$
6
per
month
to
a
homeowner
who
used
500
kWh
per
month
of
electricity.

(
Note
that
this
worst
case
total
capital
cost
estimate
for
a
100
MW
unit
to
install
LSFO
with
a
new
stack
and
a
balanced
draft
conversion
of
the
boiler
was
$
65.2
million
dollars,
2002
dollars).
9­
56
More
recent
control
cost
estimates
in
2003
dollars
calculated
for
new
IPM
modeling
indicated
that
the
cost
to
install
LFSO
for
500
MW
unit
were
as
follows:
total
capital
cost=$
236
million,
fixed
O&
M=$
9.16
per
kW/
yr
and
variable
O&
M=$
1.08
mills/
kWh.
Recent
health
data
indicated
that
if
plant
specific,
Hg
controls
were
not
required
and
not
installed
on
coal­
fired
electric
steam
generating
units,
the
same
homeowner
would
be
required
to
expend
numerous
times
more
in
healthcare
costs.
Simply
put,
air
pollution
controls
capable
of
achieving
90
percent
Hg
removal
efficiency
could
be
installed
on
all
coalfired
electric
steam
generating
units
100
MW
or
larger
at
an
average
monthly
cost
to
the
homeowner
that
is
much
more
cost
effective
than
dealing
with
its
environmental
and
health
cost
consequences.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
they
do
not
believe
that
EPA's
modeling
of
the
power
sector
has
omitted
any
control
technologies
that
are
reasonably
likely
to
be
available
or
likely
to
be
commercialized
within
the
time
frame
for
decision
and
implementation
of
Hg
control
technologies,
consistent
with
the
timelines
envisioned
by
the
Clear
Skies
Initiative.
The
preceding
response
discussed
the
problems
with
modifying
an
ESP
to
increase
collecting
plate
area
when
ACI
is
employed
and
with
the
widespread
retrofit
of
fabric
filters.

While
promoted
vigorously
by
vendors
with
a
commercial
interest
in
such
technologies,
halogenated
activated
carbons,
such
as
one
containing
bromine
or
iodine,
are
technologies
that
should
not
be
considered
commercially
available
or
proven.
While
there
has
been
a
single
test
with
brominated
ACI
that
involved
one­
half
of
the
flue
gas
stream
from
a
150
MW
unit
that
indicated
this
might
eventually
hold
some
promise,
innumerable
uncertainties
remain
with
this
technology.
A
30­
day
test
period
is
simply
insufficient
to
understand
the
long­
term
effects
that
might
be
encountered
when
such
potentially
corrosive
substances
are
injected
into
a
utility
boiler.
There
would
likely
be
effects
on
the
ability
to
sell
or
dispose
of
fly
ash,
corrosion
on
ductwork
and/
or
collecting
plates,
and
possibly
the
production
of
potentially
harmful
by­
products
such
as
dioxin.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

4.
CATF
and
Cinergy
both
modeled
more
stringent
MACT­
type
options.
CATF
assumed
that
ACI
would
be
available
in
2005
for
all
coal
types.
Cinergy
assumed
that
ACI
would
be
available
in
2005
for
all
coal
types
in
one
scenario
and
in
2010
for
9­
57
all
coal
types
for
another
scenario.
EPA
assumed
commercial
application
only
beginning
in
2010
with
70­
90
percent
removal
levels.
The
year
of
availability
for
ACI
makes
a
large
difference
in
the
projected
impacts
of
a
MACT­
type
option.
What
assumptions
for
ACI
availability
are
most
appropriate
to
consider
in
a
modeling
analysis,
at
what
quantities,
for
what
coal
types,
and
why?

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
reviewed
the
IPM
modeling
summaries
highlights
as
an
important
fact:
the
results
are
only
as
good
as
the
variables
used
in
the
model.
That
is,
the
inputs
and
assumptions
used
in
the
model
are
not
only
critical
to
its
accuracy
and
success
but,
more
importantly,
assumptions
about
availability,
control
efficiency
and
cost
(
both
capital
and
operation
and
maintenance
costs)
predetermine
its
results.
Unfortunately,
they
believed
several
of
the
assumptions
and
inputs
described
in
the
NODA
are
fundamentally
flawed
and
account
for
unrealistic
results.
For
example,
the
Cinergy
model
assumes
that
ACI
would
not
be
available
until
2010
(
five
years
from
now).
This
is
erroneous,
in
that
ACI
is
available
now.
Further,
if
a
unit
has
difficulty
complying
with
the
MACT
limit
by
2008,
using
ACI
and
the
existing
control
system
on
the
unit,
then
the
Clean
Air
Act,
under
Sections
112(
i)(
3)
and
112(
i)(
4),
contains
provisions
that
could
offer
additional
time.
Because
ACI
is
available
now
and
the
Clean
Air
Act
provides
for
extensions
for
more
substantial
control
device
addition
or
replacement,
the
commenter
does
not
agree
there
would
be
a
need
for
power
plants
to
shut
down
for
as
long
as
two
years,
as
the
Cinergy
model
assumes.
In
fact,
installation
of
ACI
requires
little
down
time
and
may
be
sufficient
on
many
plants
to
achieve
substantial
Hg
control.
With
halogenated
sorbents,
this
may
be
all
that
is
required
for
most
plants
to
achieve
90
percent
or
more
control.
In
cases
where
existing
particulate
control
at
coalfired
units
is
poor
and
needs
to
be
replaced
or
supplemented
with
more
effective
particulate
control,
the
compliance
period
for
the
rule
should
be
adequate
to
avoid
disruptions
in
power
supply.
If
needed,
more
time
can
be
allotted
on
a
case­
by­
case
basis,
long­
term
shutdowns
can
be
avoided,
and
any
shutdowns
can
be
planned
to
avoid
disruptions.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5332)
agreed
that
the
year
of
availability
of
ACI
as
a
control
option
for
Hg
is
a
key
issue
in
the
modeling
analyses.
The
Agency
has
apparently
received
many
comments
on
this
issue,
ranging
from
the
view
that
the
technology
is
commercially
available
today
to
the
opinion
that
it
will
not
be
commercially
available
until
well
after
2010.
The
commenter
does
not
have
first­
hand
information
with
respect
to
the
date
on
which
ACI
should
be
considered
a
commercially
viable
option
for
Hg
control
from
coal­
fired
power
plants.
However,
the
commenter
offers
the
following
evidence
in
support
of
the
proposition
that
this
technology
should
be
considered
available
on
the
earlier
end
of
the
time
frame
being
considered,
with
the
9­
58
caveat
that
the
effectiveness
and
cost
of
ACI
in
reducing
Hg
emissions
will
depend
to
some
degree
on
the
details
of
plant
configuration
and
type
of
coal
burned.

First,
ICAC,
which
is
the
national
trade
association
of
companies
that
supply
air
pollution
control
and
monitoring
technology,
has
gone
on
record
in
written
comments
submitted
to
EPA,
and
in
testimony
presented
at
a
Congressional
hearing,
that
ACI
systems
are
currently
available,
have
already
been
used
in
full­
scale
applications
for
the
power
sector
and
other
industrial
sectors,
and
can
be
applied
to
any
plant
configuration
and
coal
type.
It
can
be
argued
that
considerations
of
self
interest
may
contribute
to
ICAC's
conclusions.
On
the
other
hand,
ICAC's
claims
that
site­
specific
guarantees
for
activated
carbon
systems
are
being
offered
commercially
in
the
marketplace
today
for
many
plant
configurations
and
coal
types
certainly
should
not
be
ignored.

Second,
a
number
of
states,
including
Massachusetts,
New
Jersey,
Wisconsin
and
Connecticut,
have
already
promulgated
Hg
reduction
requirements.
In
some
of
these
states,
strict
Hg
reduction
requirements
are
being
imposed
in
the
2006
to
2008
timeframe,
and
compliance
will
require
use
of
ACI
or
of
another
approach
that
will
achieve
similar
levels
of
reduction.
In
developing
these
regulations,
the
states
have
conducted
evaluations
that
have
lead
them
to
conclude
that
activated
carbon
will
be
a
commercially
available
option
in
this
timeframe.

And
finally,
the
regulations
EPA
promulgates
will
themselves
play
a
role
in
driving
the
commercial
availability
of
ACI
and
other
control
technologies.
Relatively
stringent
standards
will
propel
the
commercial
availability
of
technology,
while
less
strict
requirements
will
forfeit
this
benefit.
By
the
same
token,
the
more
certainty
the
requirements
offer
from
a
legal
perspective­
whether
by
virtue
of
legislation
or
rules
that
are
likely
to
withstand
legal
challenge­
the
more
likely
the
requirements
will
be
to
drive
the
early
commercial
availability
of
controls.

Response:
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
noted
that
the
utility
of
using
ACI
as
a
control
method
was
discussed
in
the
NODA.
The
acting
principle
of
ACI
is
that
by
injecting
carbon
additional
Hg
is
captured
in
the
existing
particulate
control
device
in
a
manner
similar
to
how
the
particulate
form
of
Hg
in
the
gas
stream
is
already
being
captured.
The
commenter
states
that
it
is
in
favor
of
the
use
of
this
approach
for
significantly
reducing
Hg
emissions.
This
technology
has
been
used
to
successfully
reduce
Hg
emissions
at
several
coal­
fired
utilities
across
all
coal
types.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
9­
59
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
noted
that
brominated
activated
carbon
injection,
a
form
of
ACI
where
the
carbon
is
combined
with
bromine
before
injection,
has
demonstrated
95
percent
Hg
removal
at
Great
River
Energy's
Stanton
10
Plant.
Injecting
brominated
activated
carbon
tends
to
convert
a
higher
portion
of
the
elemental
Hg
to
the
oxidized
form.
This
is
analogous
to
the
effect
naturally
occurring
chlorine
in
coal
has
on
Hg
emissions.
Achieving
95
percent
removal
at
the
Stanton
10
Plant
is
significant
since
it
burns
lignite
coal,
which
is
generally
recognized
as
the
most
difficult
to
control.
Lignite
is
difficult
to
control,
in
part,
because
lignite's
chlorine
content
is
typically
low.
This
commenter
states
that
it
does
not
appear
that
EPA
has
considered
the
impacts
of
the
recent
improvements
to
the
ACI
technology
in
the
proposed
MACT
rule.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5447)
said
that
while
they
remain
encouraged
about
the
potential
for
ACI
and
other
Hg
control
technologies,
the
basic
facts
have
not
changed
since
the
commenter
filed
its
April
30,
2004,
comments.
No
technology,
including
ACI,
has
been
demonstrated
to
achieve
the
emission
rate
proposed
under
the
new
source
MACT
or
NSPS
regulatory
schemes
on
a
commercial
scale
for
all
but
the
lowest
Hg
content
coals.
No
vendors
of
control
technology
are
willing
to
guarantee
Hg
removal
at
the
rates
needed
to
achieve
the
proposed
new
source
emission
levels.
This
lack
of
guarantees
affects
financing,
choice
of
fuel,
and
ultimately
the
economic
viability
of
the
unit.
If
units
are
not
economically
viable,
they
will
not
be
developed
and
the
nation's
energy
supply
will
suffer.

The
commenter
noted
that
any
estimate
of
when
Hg­
specific
control
technologies
will
become
commercially
available
remains
uncertain.
All
technologies
must
be
tested
on
a
broad
range
of
coals
over
longer
periods
of
time.
Balance­
of­
plant
issues
must
be
identified
and
resolved.

EPA
must
base
its
ACI
availability
and
performance
projections
on
realistic
development
estimates
and
not
on
assumptions
that
there
will
be
"
funding
[
for
and
the]
successful
implementation
of
an
aggressive,
comprehensive
[
ACI]
research
and
development
program
at
both
EPA
and
the
U.
S.
Department
of
Energy."
69
Fed.
Reg.
69870,
col.
2­
3.
EPA
explained
in
9­
60
its
January
2004
white
paper
that
implementation
of
such
a
research
and
development
program
is
the
basis
for
its
projection
that
ACI
technology
will
be
available
for
commercial
application
after
2010
and
that
removal
levels
in
the
70­
90
percent
range
could
be
achievable.
69
Fed.
Reg.
69870,
col.
2.
In
fact,
there
is
no
assurance
that
ACI
will
be
commercially
available
by
2010.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
Commenter
is
referred
to
the
preamble
for
discussion
of
NSPS
limits.

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
contended
that
the
results
of
the
numerous
modeling
summaries
provided
in
the
NODA
are
only
as
good
as
the
input
variables.
The
December
2000
finding
clearly
established
an
"
appropriate
and
necessary"
finding
to
reduce
Hg
emissions
by
properly
developing
a
NESHAP
for
coal
fired
utility
plants.
The
commenter
believed
the
use
of
activated
carbon
injection
and
other
alternative
sorbents
which
will
reduce
Hg
emissions
from
both
bituminous
and
sub­
bituminous
coals
has
advanced
greatly
and
would
be
available
much
earlier
than
2010
as
speculated
in
some
of
IPM
runs
provided
in
the
NODA.
The
commenter
was
also
concerned
that
the
EPA
did
not
conduct,
and
provide
for
comment,
the
additional
modeling
with
the
IPM
to
evaluate
the
more
stringent
MACT
options.
This
was
previously
requested
by
the
state
environmental
agency
representatives
who
served
on
the
Federal
Advisory
Committee
Act
Utility
Workgroup.

The
IPM
input
data
comparing
MACT
based
approaches
with
alternative
regulatory
approaches
relies
solely
on
the
projected
Hg
reductions
achieved
with
using
activated
carbon
injection
(
ACI)
or
similar
sorbents.
The
analysis
presented
by
Cinergy
used
a
stringent
MACT
value
for
all
subcategories
of
coal
but
questioned
the
ability
of
ACI's
availability
by
2010.
The
DOE
recently
announced
that
six
new
projects
would
be
in
their
second
round
of
field
testing
for
ACI
and
new
sorbents.
(
This
is
in
addition
to
last
year's
selection
of
eight
projects
by
DOE.)
Both
rounds
of
testing
are
aimed
at
meeting
the
DOE's
near
term
goal
of
having
technologies
that
can
capture
50­
70
percent
of
Hg
emissions
ready
for
commercial
demonstration
by
2005
for
plants
burning
bituminous
coal
and
by
2007
for
those
burning
lower
rank
coals
and
blends.
By
2010,
the
DOE
expects
costs
to
be
reduced
by
25­
50
percent.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
9­
61
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5446)
stated
that
it
was
worth
noting
that
even
with
discrepancies
in
assumptions
models
of
a
stringent
MACT
without
sub­
categorization
or
with
inadequate
subcategorization,
predict
a
dramatic
decline
in
demand
for
sub­
bituminous
coal.
For
example,
Cinergy
modeling
of
a
strict
MACT
without
sub­
categorization1
shows
sub­
bituminous
and
lignite
plants
shutting
down
prior
to
the
availability
of
dedicated
control
technologies.
In
reality
it
is
extremely
unlikely
that
these
plants
would
shut
down
for
several
years
and
then
restart
when
control
technology
became
available.
They
would
be
far
more
likely
to
switch
fuels
or
be
permanently
retired.
In
this
case
the
very
significant
declines
in
the
use
of
subbituminous
and
lignite
coals
predicted
would
have
a
very
dramatic
impact
on
US
electricity
supplies
and
regional
economies.

In
addition,
modeling
by
the
Clean
Air
Task
Force
(
CATF)
of
an
Alternate
Mercury
Control
Scenario
with
a
reduced
level
of
sub­
categorization
showed
a
27
percent
decline
in
sub­
bituminous
coal
use
relative
to
2003.

These
results
demonstrate
that
the
EPA
must
incorporate
sub­
categorization
by
coal
rank
if
it
is
to
meet
its
commitment
of
implementing
a
rule
that
ensures
a
level
playing
field
for
all
coal
types.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
As
discussed
in
other
comment
responses,
the
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
for
EPA's
example
allocation
for
States
to
allocate
at
the
unit
level.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
stated
that
DOE
projects
that
ACI
technology,
capable
of
achieving
a
50­
70
percent
reduction
in
Hg
emissions
from
all
coal
types,
will
be
commercially
available
by
2010.
In
this
regard,
assumptions
may
be
used
for
modeling
purposes,
but
those
assumptions
must
have
a
rational
basis,
and
must
be
conservative
enough
to
take
into
account
the
uncertainty
and
variability
associated
with
ACI
controls
on
the
full
range
of
boilers
and
fuel
types.
The
commenter
referred
to
their
supplemental
Hg
rule
comments
dated
June
29,
2004:

"
A
fundamental
problem
in
developing
and
predicting
the
performance
of
mercury
control
technology
is
that
mercury
chemistry
is
poorly
understood,
particularly
in
context
to
the
9­
62
wide
range
of
conditions
encountered
in
coalfired
power
plants.
Correlations
of
mercury
speciation
with
flue
gas
composition
are
instructive,
but
have
poor
predictive
power
(
i.
e.,
wide
confidence
intervals)
as
discussed
in
the
commenter's
May
14
comments
on
the
rule.
These
numerical
correlations
fail
to
account
for
such
important
factors
as
flue
gas
and
fly
ash
composition,
including
unburned
carbon,
and
heterogeneous
gas­
solid
reactions
between
mercury
and
the
fly
ash1.
Work
on
scientifically
based
(
i.
e.,
a
priori)
chemical
models
is
underway,
but
their
usefulness
remains
to
be
seen."

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5491)
said
that
a
revolution
has
occurred
over
the
last
year
in
power­
plant
Hg­
control
technology.
Coal
chlorine
content
has
now
been
made
irrelevant.
Consequently,
the
currently­
proposed
Hg
MACT
structures,
limits,
and
timetables
need
to
be
radically
modified.

The
EPA's
current
MACT
proposals
were
based
on
a
fundamental
assumption
that
the
low
chlorine
content
of
Western
subbituminous
coals
and
lignites
severely
limited
the
performance
of
Hg
reduction
technology
with
these
fuels.

For
the
traditional
MACT
proposal,
this
resulted
in
differing
Hg
emission
floor
limits
subcategorized
by
coal
rank.

For
the
cap­
and­
trade
proposals,
this
resulted
in
differing
emission­
allowance
allocation
adjustment­
factors
by
coal
rank.

Treating
the
different
coal
ranks
differently
because
of
their
chlorine
contents
resulted
in
highly
divergent
standards
which
would
lead
to
significant
marketplace
inequities
and
distortions:

Coal
Type
Proposed
Emission
Standards
Allocation
Adjustmen
t
Factors
Existing
Plants
(
lb
Hg/
TBtus)
New
Plants
(
10­
6
lb
Hg/
MWh)

Lignite
9.2
62
3
Subbituminous
5.8
20
1.25
Bituminous
2.0
6
1
Fortunately,
vast
improvements
in
the
performance
and
cost­
effectiveness
of
activated
9­
63
carbon
injection
technology
(
ACI)
for
low­
chlorine
subbituminous
coal
and
lignites
have
recently
been
conclusively
demonstrated.
Multiple
DOE­
co­
sponsored
full­
scale
retrofit
demonstrations
by
different
contractors
of
ACI
with
brominated
carbons
at
plants
burning
low­
chlorine
fuels
this
past
year
consistently
achieved
Hg
emission
rates
of
less
than
1.0
lb
Hg/
TBtus
at
very
low
costs.
Moreover,
these
new
brominated
carbons
are
now
commercially
available
for
use
by
any
plant.
Consequently,
the
currently­
proposed
Hg
MACT
structures,
limits,
and
timetables
have
to
be
radically
modified
to
account
for
these
developments.

At
the
very
least,
the
MACT
floor
levels
or
adjustment
factors
for
subbituminous
coals
and
lignites
now
have
to
be
lowered
to
the
levels
currently
proposed
for
bituminous
coals.
More
responsibly,
subcategorized
standards
based
in
plant
particulate­
control
equipment,
rather
than
by
coal
rank,
should
be
promulgated,
with
resulting
MACT
floor
levels
of
1.0
lb
Hg/
TBtu
or
below.
If
a
cap­
and­
trade
system
is
proposed
instead,
its
2010
cap
should
be
in
the
range
of
8
to
10
tons
of
Hg
per
year,
not
34.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
for
EPA's
example
allocation
for
States
to
allocate
at
the
unit
level.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5488)
noted
that
EPA's
January
30,
2004
proposed
rule
making
erroneously
and
unlawfully
found
that
ACI
for
Hg
control
at
EGUs
is
"
not
available
on
a
commercial
basis."
As
discussed
in
the
commenter's
June
27,
2004,
comments,
this
assertion
is
manifestly
unreasonable
and
contrary
to
law.
Moreover,
EPA's
assumptions
about
the
costs
of
controlling
Hg,
which
were
never
justified,
have
now
been
rendered
virtually
meaningless
based
on
the
advances
achieved
with
low­
cost
halogenated
sorbents.

While
EPA
is
obligated
to
consider
all
comments
submitted
to
the
administrative
record,
it
should
be
extremely
skeptical
of
cost
analyses
performed
by
the
industry
to
be
regulated,
as
time
and
time
again
they
have
proven
to
be
skewed
toward
dramatically
overstating
compliance
costs.
The
assumption
made
by
Cinergy
in
its
power
sector
modeling
that
ACI
will
not
be
commercially
available
until
2010
is
a
case
in
point.
This
assumption
is
laughable,
given
that
ACI
is
commercially
available
today.
The
corresponding
suggestion
that
coal
plants
will
temporarily
have
to
shut
down
is
reminiscent
of
the
hyperbolic
statements
of
impending
doom
voiced
by
representatives
of
the
automotive
industry
when
they
faced
emissions
regulations
in
the
1970'
s.
Likewise,
Cinergy
provides
no
support
or
justification
whatsoever
for
the
increased
costs
of
SO
2
control,
increased
cost
of
SCR,
reduced
Hg
co­
benefits
and
elevated
discount
rate
that
were
assumed
in
its
modeling,
compared
to
EPA's
analysis.
9­
64
Response:

For
final
rule
modeling
analysis,
EPA
is
not
incorporating
other
commenter
assumptions
into
its
modeling
analysis.
The
assumptions
used
in
EPA
analysis
of
the
final
rule
are
discussed
in
EPA's
IPM
documentation,
available
in
the
docket.
EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5492)
noted
that
ACI
technology
is
currently
being
offered
for
sale
to
utilities.
For
example,
Council
Bluffs
Station
is
required
to
reduce
Hg
emissions
by
85
percent
or
use
an
injection
rate
of
10
lb/
mmacf.
Several
vendors
bid
on
this
system
and
offered
guarantees.
The
commenter
believes
that
an
average
70
percent
Hg
reduction
is
achievable
over
a
large
number
of
boiler
installations
using
today's
technology.
Based
on
this
input,
they
believed
that
ACI
technology
capable
of
Hg
reduction
over
a
large
number
of
installations
is
or
will
be
commercially
available
by
2007­
2008
for
all
coal
types.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
ACI
availability
and
costs.
Sorbent
injection,
either
with
conventional
activated
carbon
(
ACI)
or
chemically­
treated
carbon
(
CTC)
appears
to
reduce
Hg
in
the
flue
gas
from
on
all
coals.
However,
the
maximum
reduction
achievable
and
the
percent
reduction
at
any
given
sorbent
injection
ratio
varies
with
coal
type.
This
is
especially
true
for
ACI
at
plants
fueled
with
western
coals.
CTCs
show
promise
in
overcoming
these
constraints
for
those
fuels,
especially
at
plants
equipped
with
a
spray
dryer
and
baghouse,
but
many
questions
remain
about
this
new
technology
 
sustainable
and
widely
applicable
high
removals,
possible
emissions
of
the
treatment
chemical
and/
or
corrosion
caused
by
it,
large
quantity
availability
of
consistent
quality
material,
etc.
ACI
costs
for
70
percent
Hg
reduction
are
predicted
to
range
from
1.6
to
3.0
mills/
kWh
for
low­
sulfur
eastern
or
Western
fuels;
presumably,
most
plants
burning
medium
 
to
high­
sulfur
eastern
fuels
would
have
an
FGD
and
therefore
not
need
sorbent
injection.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
9­
65
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5429)
stated
that
during
1999,
EPA
gathered
data
as
part
of
the
ICR
program
to
measure
Hg
capture
in
emission
control
equipment
designed
to
capture
SO
2,
NO
x,
and
particulates.
These
data
showed
that
the
same
emission
control
equipment
captured
lower
amounts
of
Hg
at
plants
burning
subbituminous
and
lignite
coals.
When
sorbent­
based
Hg
control
technology
was
first
applied
to
plants
burning
these
Western
coals,
it
was
discovered
that
while
50­
70
percent
Hg
removal
was
achievable
for
units
with
ESPs,
there
appeared
to
be
a
ceiling
that
prevented
any
higher
levels
of
Hg
removal
for
these
coals
(
Durham
et.
al.,
2002).

It
was
speculated
that
the
reason
for
the
poorer
capture
of
Hg
from
Western
coals
was
that
these
coals
had
lower
concentrations
of
halogens
such
as
chlorine,
bromine,
and
fluorine.
It
appeared
that
halogens
in
coal
resulted
in
gas­
phase
species
that
were
critical
in
the
reaction
processes
that
captured
Hg.
During
2004,
research
and
development
was
conducted
to
determine
if
higher
levels
of
Hg
removal
could
be
achieved
by
supplementing
halogens
at
these
plants.
Full­
scale
field
tests
were
conducted
in
which
various
halogens
were
added
to
the
coal,
sprayed
into
the
boiler
and
impregnated
onto
the
sorbent.

During
2004,
full­
scale
field
tests
were
performed
on
plants
the
burn
subbituminous
Powder
River
Basin
(
PRB)
coals
and
lignites.
Two
key
configurations
of
emission
control
equipment
were
evaluation:

°
Spray
dryer
followed
by
a
fabric
filter
°
ESP
only
The
first
configuration
was
selected
because
the
most
likely
air
pollution
control
configurations
for
new
units
burning
subbituminous
PRB
coal
or
a
lignite
will
be
a
spray
dryer
absorber
(
SDA)
followed
by
a
fabric
filter
(
FF).
This
configuration
offers
cost
advantages
to
meet
stringent
multi­
pollutant
control
regulations.
However,
available
data
indicate
that
this
configuration
demonstrates
particularly
low,
native
Hg
removal
and
the
effectiveness
of
non­
chemically
treated
activated
carbon
is
limited
(
Sjostrom
et.
al.
2002).

The
commenter,
with
support
from
DOE
NETL
and
industry
partners,
conducted
a
Hg
control
demonstration
using
sorbent
injection
into
the
SDA­
FF
at
Sunflower
Electric's
360­
MW
Holcomb
Station.
Holcomb
Station
is
located
near
Garden
City,
Kansas.
The
unit
is
a
load­
following
sub­
critical
360­
MW
pulverized
coal
opposed­
fired
Babcock
and
Wilcox
Carolina
type
radiant
boiler
designed
to
burn
PRB
coal.
The
existing
unit
is
equipped
with
three
spray
dry
absorber
modules
followed
by
two
very
low
air/
cloth
ratio
reverse
air
fabric
filters.
Holcomb
primarily
burns
two
different
PRB
coals,
Jacobs
Ranch
and
Black
Thunder.

This
test
program
was
designed
to
provide
a
full­
scale
evaluation
of
different
technologies
that
can
overcome
the
limited
Hg
removal
achievable
at
these
sites.
Each
technology
was
based
on
supplementing
certain
halogens
that
are
not
available
in
sufficient
quantities
in
these
coals.
The
program
was
very
successful
in
that
three
different
technologies
were
found
that
have
the
9­
66
potential
to
produce
high
levels
(>
80
percent)
of
Hg
removal
in
this
difficult
application
(
Starns,
et.
al.,
2004b).
These
technologies
are:

1.
Coal
Blending:
By
blending
western
bituminous
coal
with
PRB
coal,
the
Hg
removal
across
the
system
increased
to
almost
80
percent
even
without
injecting
another
sorbent.
It
is
highly
likely
that
firing
a
blend
of
Black
Thunder
and
West
Elk
coals
with
ACI
could
result
in
greater
than
90
percent
Hg
removal.
Results
with
other
coal
blends
must
be
evaluated.

2.
Chemical
Addition
to
the
Coal:
KNX,
a
proprietary
chemical
developed
by
ALSTOM
Power,
was
found
to
enhance
the
performance
of
a
standard
activated
carbon.
Mercury
removal
of
86
percent
was
measured
at
a
carbon
feed
rate
of
just
1.0
lb/
MMacf.

3.
Chemically
Enhanced
Sorbent:
A
proprietary
product
of
NORIT
Americas,
FGD­
E3,
produced
Hg
removal
in
excess
of
90
percent.

It
should
be
noted
that
the
first
two
approaches
were
tested
for
very
short
periods
of
time.
However,
the
effects
were
verified
and
demonstrated
the
potential
of
these
technologies.
In
contrast,
the
test
program
on
NORIT's
E­
3
involved
injecting
the
enhanced
sorbent
for
four
weeks.
The
results
obtained
during
this
period
showed
very
high
levels
of
Hg
removal,
average
of
93
percent,
at
a
significantly
reduced
injection
rate
of
1.2
lb/
MMacf.
During
this
test
period
Hg
emissions
averaged
0.8
lb/
TBtu.

In
addition
to
the
Holcomb
tests,
URS
conducted
a
DOE/
NETL
sponsored
program
at
the
Great
River
Energy's
Stanton
Station
Unit
10
(
Machalek,
et.
al.,
2004).
This
unit
fires
North
Dakota
lignite
and
has
the
identical
configuration
of
a
spray
dryer/
baghouse
as
Holcomb.
During
this
test
program
two
halogenated
sorbents
were
tested,
NORIT's
E­
3
and
Sorbent
Technologies
B*
PAC.
Mercury
removal
levels
greater
than
90
percent
were
achieved
at
an
injection
rate
of
1.5
lb/
MMacf
with
both
of
these
sorbents.

Following
the
success
of
the
halogenated
sorbents
on
spray
dryer/
fabric
filters,
a
second
round
of
testing
was
conducted
on
plants
burning
subbituminous
coals
that
only
have
ESPs
for
emission
control.
This
configuration
represents
the
majority
of
existing
plants
that
burn
subbituminous
coals
and
was
therefore
very
important
to
the
industry.
Two
tests
were
conducted
during
the
summer
and
fall
of
2004.
The
commenter
conducted
a
test
program
at
the
Ameren
Meramec
Station,
which
burns
100
percent
PRB
coal,
as
part
of
a
DOE/
NETL
sponsored
program
(
Starns
et.
al.,
2004c).

During
this
program,
the
performance
of
NORIT
standard
carbon
Darco
FOD
was
compared
to
the
halogenated
version
Darco
FOD
E­
3.
With
the
standard
carbon,
the
"
ceiling
effect"
is
observed
in
that
a
maximum
removal
of
about
70
percent
Hg
removal
is
achieved
at
a
feed
rate
of
3­
5
lb/
MMacf.
No
additional
Hg
removal
is
obtained
even
if
the
carbon
feed
rate
is
double
and
tripled.
In
contract,
the
E­
3
overcomes
this
effect
and
greater
than
90
percent
Hg
removal
is
achieved
at
a
feed
rate
of
3
lb/
MMacf.

A
similar
program
was
conducted
by
Sorbent
Technologies
at
the
Detroit
Edison
St.
Clair
Station
(
Nelson,
et.
al.,
2004).
This
unit
burns
a
blend
of
85
percent
PRB
coal
with
15
percent
9­
67
Eastern
bituminous
coal.
This
test
involved
the
one
month
evaluation
of
Hg
removal
using
Sorbent
Technology's
brominated
activated
carbon
B*
PAC
injected
upstream
of
the
cold­
side
ESP.
During
the
duration
of
the
test
program,
B­
PAC
removed
94
percent
of
the
Hg
emissions
when
injected
at
a
rate
of
3
lb/
MMacf.
The
Hg
emission
rate
was
reduced
to
0.4
lb/
TBtu.

The
Department
of
Energy
National
Technology
Laboratory,
Southern
Company,
and
EPRI
funded
a
program
to
evaluate
sorbent
injection
for
Hg
control
for
a
year
of
continuous
operation
(
Bustard
et.
al.,
2004;
Berry
et.
al.,
2004).
The
test
was
conducted
at
Alabama
Power
Company's
Plant
Gaston
Unit
3.
The
overall
objective
was
to
evaluate
the
long­
term
effects
of
sorbent
injection
on
Hg
capture
and
COHPAC
®
performance.
Data
from
the
testing
will
be
used
to
determine:

1.
Air­
to­
cloth
ratio;
2.
Advantages/
disadvantages
of
high­
permeability
fabrics;
and
3.
Design
criteria
and
costs
for
new
TOXECONTM
systems.

Long­
Term
Original
Bags
Activated
carbon
was
injected
into
the
COHPAC
baghouse
nearly
continuously
from
June
26
through
November
25.
Figure
6
presents
a
snapshot
of
data
during
the
long­
term
test.
Inlet
and
outlet
total
vapor­
phase
Hg,
calculated
Hg
removal,
carbon
injection
concentration,
baghouse
cleaning
frequency,
and
inlet
mass
loading
are
presented.
Mercury
removal
varied
between
50
and
98
percent,
with
an
overall
average
of
86
percent.

One
thing
that
was
clear
from
these
tests
was
that
the
current
air­
to­
cloth
ratio
was
too
high
to
inject
sufficient
carbon
to
achieve
90
percent
Hg
control.
A
new
TOXECON
baghouse
would
have
to
be
designed
at
a
lower
air­
to­
cloth
ratio.
One
way
to
overcome
the
operating
limitations
at
this
site
was
to
operate
at
low
load/
lower
flow
for
an
extended
period.
While
at
these
conditions,
carbon
injection
could
be
increased
and
performance
data
could
be
tracked.
The
primary
objectives
of
these
short
tests
were
to
1)
determine
the
injection
concentration
necessary
to
achieve
90
percent
removal
and
2)
determine
the
impact
of
carbon
injection
on
cleaning
frequency
at
this
lower
air­
to­
cloth
(
A/
C)
ratio.
An
educated
estimate
of
the
ideal
air­
to­
cloth
ratio
was
about
6.0
ft/
min.

Southern
Company
was
able
to
schedule
an
extended
period
of
low
load
operation
for
Gaston
Unit
3.
Three
injection
rates
were
evaluated
during
the
72­
hour
test.
The
first
test
was
conducted
at
the
highest
injection
rate
possible
under
normal
operating
conditions,
20
lb/
h.
At
this
rate
and
the
lower
flow,
the
injection
concentration
was
0.9
lb/
MMacf
instead
of
0.6
lbs/
MMacf.
The
injection
concentrations
were
then
increased
up
to
a
maximum
of
nominally
3.3
lb/
MMacf.

The
results
from
this
test,
including
inlet
and
outlet
Hg
concentrations,
Hg
removal,
and
cleaning
frequency
are
presented
in
Table
1.
At
an
injection
concentration
of
0.9
lb/
MMacf,
Hg
removal
was
between
80
and
90
percent.
When
injection
concentration
was
increased
above
2
lb/
MMacf,
Hg
removal
was
well
above
90
percent
and
there
were
no
episodes
when
the
removal
dropped
below
this
level.
Cleaning
frequency
was
acceptable
at
all
injection
rates.
9­
68
Table
1.
Results
Summary
from
Low­
Load
Tests,
November
2003
Injection
Rate
(
lb/
h)
Injection
Concentration
(
lbs/
MMacf)
Inlet
Hg
Concentration
(

g/
Nm3)
Outlet
Hg
Concentration
(

g/
Nm3)
RE
(%)
Cleaning
Frequency
(
pulses/
bag/
hour)

20
0.9
20.6
3.2
84.2
0.6
45a
2.0
22.2
1.0
94.6
0.8
70
3.3
21.4
0.61
97.1
1.4
a
Last
18
hours
of
45
lb/
h
test.

A
set
(
2,300
bags)
of
high­
perm
bags
was
purchased
and
installed
in
the
B­
side
baghouse.
The
differences
in
design
were
denier
(
an
indication
of
fiber
diameter;
2.7
versus
7.0
denier)
and
permeability
(
nominally
30
versus
130
cfm/
ft2
@
0.5"
H
2
O).
The
primary
goals
for
this
test
were
to:

1.
Demonstrate
improved
pressure
drop
performance
of
the
high­
perm
bags;
and
2.
Increase
carbon
injection
concentration
to
achieve
a
higher
Hg
removal
than
was
possible
with
the
original
bags.

Carbon
injection
rate
was
incrementally
increased
from
20
to
45
lb/
h.
Because
baghouse
cleaning
frequency
was
acceptable,
it
was
possible
to
inject
at
a
constant
rate
and
not
reduce
injection
when
inlet
mass
loading
increased.
Average
Hg
removal
for
five
different
injection
conditions
is
shown
in
Table
2.
The
average
Hg
removal
was
higher
in
each
of
the
shorter
tests
than
the
85.6
percent
removal
that
was
measured
for
the
four­
month
carbon
injection
tests
with
the
original
bags.
These
tests
show
that
there
is
no
difference
in
the
effectiveness
of
carbon
injection
for
Hg
control
using
either
the
original
bags
or
the
high­
perm
bags.

Table
2.
Average
Mercury
Removal,
Inlet
Mass
Loading,
and
Cleaning
Frequency
with
High
Perm
Bags
Injection
Rate
(
lb/
h)
Injection
Concentration
(
lbs/
MMacf)
RE
(%)
Inlet
Mass
Loading
(
gr/
acf)
Cleaning
Frequency
(
pulses/
bag/
hour)
20
0.6
87
0.1
0.6
25
0.8
91
0.05
0.7
30
1.0
94
0.06
0.7
35
1.1
93
0.02
0.6
45a
1.3a
92a
0.05a
1.0a
a
Long­
term
test­
these
data
are
from
only
the
first
two
weeks
at
this
condition.

Because
it
is
expected
that
cleaning
frequency
will
increase
over
time,
especially
as
the
new
bags
season,
the
long­
term
tests
were
conducted
at
an
injection
rate
of
45
lb/
h.
For
a
two
week
period
with
an
injection
rate
of
45
lbs/
h
(
1.3
lb/
MMacf),
Hg
removal
was
92
percent,
with
a
9­
69
maximum
hourly
value
of
98
percent
and
a
minimum
hourly
value
of
80
percent.

Conclusions
from
Long­
Term
Test
°
TOXECON
units
designed
at
lower
air­
to­
cloth
ratios
than
COHPAC
units
are
capable
of
high,
90
percent,
Hg
removal.
For
TOXECON
baghouses,
it
is
recommended
that
the
maximum
design
gross
air­
to­
cloth
ratio
be
6.0
ft/
min.

°
Activated
carbon
injection
systems
are
simple,
reliable,
and
commercially
available.
The
control
programs
can
be
easily
adapted
to
varying
operating
requirements.

°
Continuous
Hg
measurements
are
challenging
but
possible.
Advancements
to
the
analyzers
were
made
and
the
analyzers
operated
24/
7
for
nearly
20
months.

°
Activated
carbon
effectively
reduced
Hg
emissions
for
extended
periods
over
a
wide
range
of
operating
variables
with
a
COHPAC
baghouse.

°
At
an
average
injection
concentration
of
0.55
lb/
MMacf,
over
a
four­
month
period
average
Hg
removal
was
86
percent.

°
For
these
tests,
injection
concentration
was
limited
by
high,
baseline
COHPAC
cleaning
frequency.

°
High
inlet
loading
into
the
COHPAC
baghouse
contributed
to
variable
baseline
Hg
removal.
It
is
also
believed
that
these
conditions
allowed
for
higher
Hg
removal
at
a
relatively
low
carbon
injection
concentration.

°
Replacing
the
original
2.7
denier
bags
with
7
denier,
high­
perm
bags,
improved
the
COHPAC's
ability
to
handle
periods
of
high
inlet
loading.

°
Short
tests
at
higher
injection
rates
with
the
high­
perm
bags
showed
that
is
was
possible
to
achieve
greater
than
90
percent
average
Hg
removal.
However,
Hg
removal
still
varied
between
80
and
98
percent
during
these
periods
and
higher
injection
rates
would
be
required
to
maintain
consistent,
90
percent
removal.

EPRI
TOXECON
TECHNOLOGIES
For
some
plants,
one
of
the
disadvantages
of
injecting
activated
carbon
is
its
impact
on
the
salability
or
reuse
of
ash.
Tests
have
shown
that
the
activated
carbon
interferes
with
chemicals
used
in
making
concrete.
One
straightforward,
cost­
effective
approach
to
achieving
high
Hg
removal
without
contaminating
the
fly
ash
is
the
use
of
the
EPRI
COHPAC
®
(
COHPAC)
and
TOXECON
 
(
TOXECON)
processes
that
are
currently
commercially
available.
COHPAC
is
an
EPRI­
patented
concept
that
places
a
high
air­
to­
cloth
ratio
baghouse
downstream
of
an
existing
ESP
to
improve
overall
particulate
collection
efficiency.
The
process
becomes
TOXECON
when
a
sorbent
such
as
activated
carbon
is
injected
upstream
of
the
baghouse
located
downstream
of
an
ESP.
With
this
configuration,
the
ash
collected
upstream
of
the
carbon
injection
remains
acceptable
for
sale
(
typically
>
99
percent
of
the
ash.)
The
downstream
baghouse
provides
an
9­
70
effective
mechanism
for
the
activated
carbon
to
have
intimate
contact
with
vapor­
phase
Hg,
resulting
in
high
levels
of
Hg
control
at
relatively
low
sorbent
injection
rates.

The
advantages
of
the
TOXECON
configuration
are:

°
Sorbents
are
mixed
with
a
small
fraction
of
the
ash
(
nominally
1
percent),
which
reduces
the
impact
on
ash
reuse
and
waste
disposal.

°
Full­
scale
field
tests
have
confirmed
that
fabric
filters
require
only
10­
20
percent
of
the
sorbent
required
by
ESPs
to
achieve
similar
removal
efficiencies.

°
Capital
costs
for
COHPAC
are
less
than
other
options
such
as
replacing
the
ESP
with
a
full­
sized
baghouse
or
larger
ESP.

°
COHPAC
requires
much
less
physical
space
than
either
a
larger
ESP
or
full­
size
baghouse
system.

°
Outage
time
can
be
significantly
reduced
with
COHPAC
systems
in
comparison
to
major
ESP
rebuilds/
upgrades.

The
TOXECON
 
configuration
offers
an
advantage
over
injecting
carbon
ahead
of
a
single
particulate
control
device
because
it
prevents
contaminating
fly
ash
with
carbon.
Although
it
is
a
highly
effective
configuration
for
removing
Hg
from
flue
gas,
retrofitting
existing
plants
with
a
baghouse
can
be
expensive.
An
attractive
alternative
solution
is
EPRI's
TOXECON
II
 
technology,
in
which
the
same
effect
can
be
achieved
without
a
baghouse
but
instead
uses
the
existing
multi­
field
ESP
alone.
In
this
configuration,
carbon
is
injected
within
the
ESP
into
downstream
collecting
fields.
The
majority
of
the
fly
ash
is
collected
in
the
inlet
ESP
fields
while
carbon
is
injected
in
one
or
more
downstream
ESP
fields.
With
this
approach,
most
of
the
fly
ash
in
the
flue
gas
will
have
been
collected
in
the
first
several
fields
(
in
general,
70­
90
percent
of
the
ash
in
flue
gas
is
collected
in
each
field),
and
beneficial
use
of
this
ash
can
is
preserved
since
it
will
contain
no
carbon.
The
remaining
fields
of
the
ESP
will
then
serve
to
collect
the
injected
carbon.
Any
ESP
with
multiple
fields
can
potentially
use
this
approach.
Besides
activated
carbon,
other
sorbents
that
can
capture
Hg
can
be
used.

The
main
advantages
of
this
approach
are:

°
preservation
of
the
large
majority
of
fly
ash
sales,
°
potential
for
sorbent
recycle,
regeneration
and
reuse,
°
enhanced
oxidation
of
elemental
Hg
to
increase
capture
in
a
downstream
scrubber,
°
minimal
capital
cost,
and
°
minimizes
amount
of
Hg­
bearing
byproducts
needing
processing
or
disposal.

In
August
of
2004,
the
commenter
first
reported
the
results
of
the
first
full­
scale
evaluation
of
TOXECON
II
 
at
Coal
Creek
Station
through
a
program
funded
by
Great
River
Energy
and
EPRI
(
Starns,
et
al.
2004a).
These
short­
term
tests
demonstrated
promise
for
Hg
removals
of
>
70
percent.
Results
with
the
mid­
ESP
injection
of
TOXECON
II
 
are
comparable
to
those
obtained
injecting
the
sorbent
upstream
of
the
ESP.
9­
71
The
commenter
stated
that
this
technology
is
based
on
the
fact
that
up
to
90
percent
in­
flight
capture
of
Hg
can
be
achieved
with
a
residence
time
of
only
one­
half
second
as
demonstrated
on
their
earlier
programs
funded
by
NETL.
In
an
ESP,
the
gas
velocity
is
4­
6
feet
per
second,
so
a
one­
half
second
residence
time
requires
2­
3
feet
of
space.
This
amount
of
space
is
often
available
between
sections
of
an
ESP.

It
should
also
be
noted
that
the
data
was
obtained
using
the
standard
NORIT
Carbon
Darco
FOD.
In
both
cases
the
"
ceiling
effect"
is
clearly
visible
indicating
the
deficiency
of
gas­
phase
halogens.
During
2005,
the
commenter
will
conduct
a
full­
scale
field
test
of
TOXECON
II
 
on
a
plant
burning
100
percent
PRB
coal.
The
halogenated
sorbent
E­
3
will
be
tested
at
this
site.
If
these
tests
confirm
the
performance
of
this
advanced
sorbent
for
this
application,
then
higher
levels
of
Hg
removal
will
be
achieved
at
greatly
reduced
injection
rates.
Keeping
the
sorbent
injection
rates
low
minimizes
the
potential
of
any
negative
effects
of
the
carbon
on
the
electrical
components
in
the
ESP.
The
combination
of
TOXECON
II
and
E­
3
would
provide
a
very
low
cost
option
for
plants
burning
Western
coals
that
want
to
achieve
high
levels
of
Hg
control
while
continuing
to
sell
the
majority
of
their
ash.

Impact
of
Enhanced
Sorbents
on
Economics
of
Mercury
Control
The
commenter
stated
that
based
upon
the
results
of
the
first
four
full­
scale
field
tests,
cost
estimates
were
made
for
applying
this
technology
to
the
US
fleet
of
coal­
fired
boilers.
In
an
EPA
analysis,
it
was
concluded
that
80­
90
percent
control
of
Hg
for
the
majority
of
plants
could
be
achieved
for
less
than
$
2/
MWh
(
Srivastava
et.
al.,
2004).
A
DOE
analysis
concluded
that
60­
90
percent
Hg
removal
would
cost
between
1.3
and
2.4
$/
MWh
depending
on
the
coal
and
type
of
emission
control
equipment
(
Hoffmann
and
Ratafia­
Brown;
2003).
In
addition,
DOE
has
established
goals
of
reducing
costs
over
time
by
25­
50
percent
by
funding
full­
scale
field
tests
of
improved
technology.

The
test
results
achieved
during
2004
show
significant
improvement
in
both
the
levels
of
Hg
removal
achievable
and
the
cost
of
control
technology.
From
four
different
full­
scale
field
test
programs
conducted
on
PRB,
lignite,
and
PRB/
bituminous
blends,
greater
than
90
percent
Hg
removal
was
achieved
on
the
most
difficult
emission
control
equipment
configurations
at
a
cost
of
less
than
$
0.6/
MWhr.
This
shows
how
rapidly
the
sorbent­
based
Hg
control
technology
is
advancing.

It
should
also
be
pointed
out
that
one
of
the
additional
advantages
of
the
technology
is
that
all
of
the
users
can
benefit
from
the
improvements
in
sorbents
as
they
become
available.
The
technology
is
sufficiently
generic
that
the
improved
products
can
be
feed
using
the
same
sorbent
storage
and
feed
equipment.
This
means
that
as
additional
progress
is
made
in
sorbents
over
the
next
3
to
5
years
resulting
in
even
lower
costs,
the
power
industry
will
be
able
to
take
advantage
of
the
improvements
even
if
it
purchase
the
equipment
today.
In
other
words,
an
early
adopter
is
not
stuck
with
2004
technology
if
a
decision
is
made
today
on
equipment
for
2008.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
9­
72
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
second
ACI
option
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
agreed
with
EPA
that
Cinergy's
assumption
concerning
the
date
of
availability
of
ACI
drives
the
results
of
this
analysis,
and
focused
our
comments
on
this
issue.
EPA
has
already
stated
that
it
is
aware
of
additional
Hg
data,
particularly
the
testing
of
various
halogenated
sorbents.
Given
the
success
of
the
halogenated
sorbents
in
capturing
Hg
during
initial
testing,
it
is
no
surprise
that
over
extended
test
periods
(
30
days),
these
sorbents
delivered
Hg
reductions
higher
than
90
percent
at
these
subbituminous
coal­
fired
boilers.
Given
the
most
recent
test
data
and
the
numerous
studies
presented
at
the
2004
"
Mega­
Symposium"
(
EPA
was
a
sponsor,
so
the
agency
is
surely
aware
of
the
data
presented),
the
agency
must
concede
that
a
national
Hg
reduction
well
in
excess
of
30
percent
is
achievable.

At
issue
then
is
the
timing
of
the
availability
of
such
controls.
EPA
has
received
assurances
from
the
Institute
of
Clean
Air
Companies
(
ICAC)
that
the
equipment
and
manpower
needed
to
design,
manufacture
and
install
the
control
equipment
will
be
available
to
meet
the
requirements
of
a
MACT
standard.
Industry
counters
with
the
assertions
that
neither
the
equipment
nor
the
manpower
will
be
available
and
further
that
the
performance
of
the
technology
performance
is
not
assured.

The
commenter
has
explored
the
issue
of
new
technology
acceptance
in
the
electric
power
sector
and
their
analysis
lends
valuable
insight
into
where
Hg
control
technology
is
today
in
terms
of
commercialization
and
adoption.
Basically,
the
development
and
acceptance
of
new
technology
has
followed
6
steps.
They
are:

1.
Laboratory
testing,
2.
Pilot­
scale
testing,
3.
Full­
scale
field
tests,
4.
Full­
scale
tests
at
multiple
sites,
5.
Long­
term
demonstration
at
several
sites,
and
6.
Widespread
implementation.

Regarding
the
first
two
steps,
laboratory
and
pilot­
scale
testing
of
Hg
control
technologies
took
place
in
the
early
to
mid­
90s.
Full­
scale
field
tests,
including
full­
scale
tests
at
multiple
sites
were
completed
during
2001­
2003
as
Table
1
illustrates.
Table
1
lists
the
facilities
by
coal
type
and
within
each
coal
type
in
roughly
chronological
order.
Thus,
it
is
apparent
that
during
the
later
tests,
as
the
technology
has
rapidly
advanced,
the
Hg­
capture
efficiency
has
increased
to
the
90
percent
range
across
all
coal
types.
In
addition,
it
can
be
seen
that
the
earlier
tests
required
considerably
more
carbon
to
achieve
the
same
results
as
the
later
tests
with
halogenated
sorbents.
The
need
for
less
carbon
will
considerably
reduce
control
costs.
9­
73
Table
1.
Full­
Scale
Tests
of
Sorbent
Injection
Completed:
2001­
2003
Site
Coal
Equipment
Injection
Rate
(
lb/
MMacf)
Percent
Hg
Capture
Brayton
Point
LS­
Bituminous
ESP
(
2)
10
94.5%

PGE
LS­
Bituminous
ESP
10
90%

Cliffside
LS­
Bituminous
HS­
ESP
6.4
>
80%

Gaston
LS­
Bituminous
HSESP
COHPAC
0.55
86%

Lausche
HS­
Bituminous
ESP
4
70%

St.
Clair
Bit./
Sub.
Blend
ESP
3
90%

Pleasant
Prairie
Subbituminous
ESP
11.3
66%

St.
Clair
Subbituminous
ESP
3
94+%

Holcomb
Subbituminous
SDA/
FF
1.2
93%

Meramec
Subbituminous
ESP
3
90%

Stanton
10
Lignite
SDA/
FF
1.5
95%

Stanton
10
Lignite
SDA/
FF
1.5
90%
Source:
Durham,
M.
D.
Advances
in
mercury
control
technology
to
meet
future
needs.
Presented
at
PowerGen,
December
2,
2004.
Orlando,
Florida.

Step
5
entails
long­
term
demonstrations
at
multiple
sites.
A
year­
long
test
has
already
been
completed
at
the
Gaston
plant
(
average
reduction
86
percent
with
an
average
performing
sorbent)
and
3
other
month­
long
tests
have
also
been
completed
with
success
at
the
Holcomb,
St.
Clair
and
Meramec
stations.
As
shown
in
Table
2,
numerous
other
full­
scale
tests
at
a
variety
of
plants
are
either
ongoing
or
scheduled
in
the
2004­
2005
timeframe.

The
commenter
also
note
that
state
Hg
rules
will
go
into
effect
by
2008,
which
will
provide
additional
long­
term
commercial
experience
with
Hg
controls.
Compliance
with
some
of
the
state
rules
begins
in
2008,
consequently
these
facilities
will
have
installed,
tested
and
operated
ACI
systems
long
before
the
compliance
date.
By
2008,
15
boilers
in
Massachusetts,
Connecticut,
and
New
Jersey
will
be
controlling
Hg
by
more
than
90
percent.
These
bituminous­
fired
boilers
have
control
configurations
that
are
similar
to
60
percent
of
the
fleet
and
will
provide
the
early
proving
ground
that
industry
maintains
is
needed
prior
to
widespread
implementation
of
this
technology.

Given
this
systematic
evolution
of
the
adaptation
of
activated
carbon
technology
to
the
power
sector,
the
commenter
was
confident
that
this
technology
will
not
just
be
available
prior
to
2010
but
widely
commercially
available
in
time
to
facilitate
compliance
with
a
2008
MACT
standard.
The
commenter
also
noted
for
the
record
that
not
all
plants
will
need
to
use
ACI
to
comply
with
a
stringent
standard.
Conventional
controls
will
achieve
a
stringent
emissions
level
for
many
plants,
and
precombustion
controls
and
other
technologies
not
represented
in
the
IPM
(
e.
g.,
oxidizing
catalysts
and
multipollutant
controls)
will
also
be
options.
9­
74
Table
2.
Full­
Scale
Tests
of
Sorbent
Injection
Ongoing
and
Scheduled:
2004­
2005
Site
Coal
Equipment
Company
Gaston
Low­
S
Bit
FF
ADA­
ES
Holcomb
PRB
SDA/
FF
ADA­
ES
Arapohoe
PRB
FF
ADA
Tech
Stanton
10
ND
Lignite
SDA/
FF
Apogee
Yates
1
Low­
S
Bit
ESP/
FGD
URS
Yates
2
Low­
S
Bit
ESP
URS
Leland
Olds
ND
Lignite
C­
ESP
EERC
Meramec
PRB
C­
ESP
ADA­
ES
Buck
Low­
S
Bit
H­
ESPC­
ESP
Sorbent
Tech
St.
Clair
PRB/
Bit
C­
ESP
Sorbent
Tech
Miami
Fort
High­
S
Bit
C­
ESP
ADA
Tech
Conesville
High­
S
Bit
ESP/
FGD
ADA­
ES
Nanticoke
PRB/
Bit
ESP
ADA­
ES
Arapahoe
PRB
FF
ADA
Tech
Antelope
Valley
ND
Lignite
SDA/
FF
EERC
Stanton
1
ND
Lignite
C­
ESP
Apogee
M.
R.
Young
ND
Lignite
FGD
EERC
Monticello
TX
Lignite
FGD
EERC
Source:
Durham,
M.
D.
Advances
in
mercury
control
technology
to
meet
future
needs.
Presented
at
PowerGen,
December
2,
2004.
Orlando,
Florida.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5566)
submitting
documentation
to
support
its
position
that
technology
to
capture
Hg
from
power
plant
flue
gas
is
readily
available,
effective,
and
affordable.
Hence,
the
commenter
urges
the
U.
S.
Environmental
Protection
Agency
to
finalize
expeditiously
a
Maximum
Achievable
Control
Technology
standard
that
reflects
the
state
of
technology
and
the
legal
requirements
of
Section
112
of
the
Clean
Air
Act.

Recent
large
scale
tests
have
been
completed
at
several
power
plants
nationwide
that
9­
75
demonstrate
high
Hg
removal
is
possible
using
sorbent
injection
(
see
attached).

Activated
carbon
injection
systems
are
simple,
reliable,
and
commercially
available.
The
control
programs
can
be
easily
adapted
to
varying
operating
requirements.
Over
a
four­
month
period
average
mercury
removal
was
86
percent.
(
Berry,
Irvin,
Monroe,
et.
al.,
2004)

Three
different
technologies
[
coal
blending,
chemical
additives,
and
chemically
enhanced
sorbents]
were
found
that
have
the
potential
to
produce
high
levels
(>
80
percent)
of
mercury
removal
in
[
power
plants
that
burn
PRB
coal).
(
Sjostrom,
Starns,
Amrhein,
et.
al.,
2004)

Recent
analysis
completed
by
the
commenter
found
the
cost
of
high
Hg
removal
to
be
affordable
(
see
attached).
Using
EPA's
cost
estimates
for
installing
sorbent
injection
and
advanced
dry
scrubbers,
the
commenter
found
that
90
percent
Hg
control
would
cost
an
average
of
0.15
and
0.22
cents/
kWh,
a
one
to
three
percent
increase.
These
cost
figures
are
in
line
with
estimates
previously
published
by
the
Institute
of
Clean
Air
Companies,
which
estimates
a
1.2
to
3.7
percent
increase,
and
by
the
Department
of
Energy
which
estimates
that
60­
90
percent
control
would
cost
0.191
to
0.236
cents/
kWh.

[
The
commenter's]
analysis
found
that
retrofitting
every
coal­
fired
utility
boiler
with
mercury
control
equipment...
would
cost
the
average
household
from
about
70
cents
to
over
$
2.00
a
month...
The
cost
of
attaining
90
percent
mercury
control
is
only
slightly
higher
than
70­
80
percent
control.

Finally,
to
date,
four
states
have
finalized
rules
requiring
coal­
fired
power
plants
to
make
significant
cuts
in
its
Hg
emissions
by
the
end
of
the
decade
(
see
attached).
According
to
the
Institute
of
Clean
Air
Companies,
power
plants
already
are
bidding
on
or
finalizing
contracts
for
Hg
control
equipment.
Over
50
plants
likely
will
be
affected
by
the
new
rules
finalized
by
the
states
of
Connecticut,
Massachusetts,
Wisconsin,
and
New
Jersey.
The
pollution
control
market
is
responding
to
the
increasing
demand,
making
it
feasible
for
companies
to
meet
tight
Hg
limits.

The
EPA
has
at
its
disposal
extensive
technical
documentation
to
support
a
stringent
MACT
standard
for
coal­
fired
power
plants,
a
standard
that
would
achieve
reductions
comparable
to
those
achieved
through
other
MACT
standards.
A
stringent
standard
with
flexible
compliance
mechanisms
can
be
developed
to
ensure
that
the
timing
and
level
of
reductions
are
not
compromised.
The
commenter
urges
the
EPA
to
explore
all
options
in
fashioning
a
MACT
rule
for
coal­
fired
power
plants,
and
to
adopt
an
appropriate
MACT
rule
expeditiously.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
9­
76
Comment:

The
commenter
(
OAR­
2002­
0056­
5519)
assumed
that
EPA
would
use
the
most
recent
definition
of
"
commercially
available"
advocated
by
representatives
of
the
electric
power
industry;
that
is,
"
technology
that
has
gone
through
at
least
one
year
of
long­
term
testing,"
one
would
have
concluded
that
sorbent­
based
technologies
(
including
activated
carbon
injection)
and
other
combinations
of
technology
used
in
series;
[
including
selective
catalytic
reduction
(
SCR),
flue
gas
desulfurization
(
FGD)
and
fabric
filters
(
FF)],
were
currently
commercially
available.
If
EPA
wold
include
in
its
determination
of
commercial
availability
all
of
the
technologies
that
had
already
been
used
for
at
least
the
past
5
years
by
coal­
fired
power
plants
located
in
Europe;
for
example,
wet
electrostatic
precipitators
(
wet­
ESPs),
EPA
would
be
forced
to
conclude
that
those
technologies
are
not
only
commercially
available,
but
also
proven
in
practice.

The
commenter
was
pleased
to
provide
the
following
additional
technical
information
to
support
these
comments
and
responded
to
EPA's
request
on
the
availability
and
cost
effectiveness
of
these
controls:

1.
"
Field
Test
Program
for
Long­
Term
Operation
of
a
COHP
AC
System
for
Removing
Mercury
from
Coal­
Fire
Flue
Gas,"
Report
No.
41591R09,
October
25,2004,
(
Attachment
#
9),

2.
"
Evaluation
of
Sorbent
Injection
for
Mercury
Control,"
Report
No.
41986R04,
October
29,
2004,
(
Attachment
#
10),

3.
"
Pilot
Testing
of
Oxidation
Catalysts
for
Enhanced
Mercury
Control
by
Wet
FGD,"
Paper
#
36,
Mega
Symposium,
(
Attachment
#
11),
and
4.
Field
Test
Program
to
Develop
Comprehensive
Design,
Operating
and
Cost
Data
for
Mercury
Control
Systems
on
Non­
Scrubbed
Coal­
Fired
Boilers,
Report
No.
41005R19,
October
25,
2004,
(
Attachment
#
12).

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5477)
referenced
the
cost
of
Hg
control
technologies
by
stating
that
it
is
also
important
to
note
that
both
the
capital
costs
and
cost
effectiveness
of
controlling
Hg
from
coal­
fired
boilers
need
to
be
presented
in
a
realistic
manner.
For
example,
a
common
but
quite
misleading
practice
is
to
present
cost
effectiveness
in
terms
of
dollars
per
pound
of
Hg
removed
from
the
application
of
ACI
or
other
technologies
and
compare
this
to
the
costs
of
controlling
a
ton
of
NO
x
or
SO
2
from
power
plants.
For
example,
typical
values
of
cost
effectiveness
are
as
follows:
$
5,000
to
$
30,000
per
pound
of
Hg
removed
for
ACI;
$
100
to
$
200
9­
77
per
ton
of
SO
2
removed;
and
$
1,000
to
$
1,500
per
ton
of
NO
x
removed.
Obviously,
the
control
costs
appear
high
using
such
a
comparison
because
Hg
is
emitted
in
far
smaller
quantities
than
conventional
pollutants
(
in
the
U.
S.,
power
plants
currently
emit
"
only"
48
tons
per
year
of
Hg;
compared
to
5
million
tons
per
year
of
NO
x
and
over
10
million
tons
per
year
of
SO
2).
Control
costs
for
Hg
on
a
pound
for
pound
or
ton
for
ton
basis
are
therefore
necessarily
higher.
However,
it
must
be
emphasized
that
Hg
presents
a
far
greater
public
health
and
environmental
hazard
on
an
equivalent
mass
basis
when
compared
to
criteria
pollutants
such
as
SO
2
and
NO
x.

A
more
illuminating
metric
for
estimating
true
costs
of
technology
for
a
project
is
when
the
costs
of
controlling
Hg
with
a
technology
such
as
ACI
are
expressed
in
terms
of
cost
to
the
ratepayer
(
e.
g.,
mills
per
kWh
of
electricity).
When
this
approach
is
followed,
the
costs
are
even
lower
than
the
costs
currently
being
incurred
for
control
of
pollutants
such
as
NO
x
from
EGUs.
Note
that
these
values
for
NO
x
are
considered
cost­
effective
by
industry
and
regulatory
agencies,
and
were
the
basis
for
recent
(
1997­
1998)
state
and
federal
requirements
for
wide­
scale
NO
x
reductions
from
EGUs
in
the
eastern
U.
S.
under
"
Section
110
Transport
SIP
call"
as
well
as
the
EPA's
newly
proposed
(
on
January
30,
2004)
Clean
Air
Interstate
Rule
(
CAIR).

Response:

EPA's
modeling
of
the
final
rulemaking
includes
presentation
of
results
in
several
metrics
including
marginal
cost
and
retail
electricity
prices.
See
Chapter
7
of
Final
CAMR
RIA
for
further
discussion
of
rulemaking
analysis.

Comment:

The
commenter,(
OAR­
2002­
0056­
5404),
in
response
to
EPA's
request
for
comment
regarding
the
various
assumptions
used
for
the
modeling
analyses
conducted
by
EPA,
CCAP,
Cinergy,
CATF
and
EEI,
submitted
that
its
analysis
is
based
on
the
most
accurate
assumptions
and
therefore
results
in
the
most
accurate
predictions
regarding
compliance
costs
and
the
timing
of
emissions
reductions
expected
as
a
result
of
EPA's
proposed
utility
Hg
rule.
Moreover,
the
generic
industry­
wide
cost
projections
derived
from
the
commenter's
modeling
are
fully
supported
by
the
more
recent
company­
specific
cost
estimates
completed
as
part
of
the
commenter's
cost
recovery
filings
with
its
state
utility
commission.
The
commenter
noted
that
other
commenters
modeled
the
effects
of
EPA's
Hg
utility
rule
using
overly
optimistic
assumptions,
which
rendered
overly
optimistic
conclusions
regarding
costs
and
achievability.
According
to
the
commenter,
because
their
analysis
is
based
on
the
most
realistic
assumptions,
the
commenter's
analysis
most
accurately
models
the
impacts
of
cost
and
timing
associated
with
EPA's
Hg
utility
rule.

The
commenter
noted
that
EPA
recently
published
revised
assumptions
documentation
used
for
its
Integrated
Planning
Model
(
IPM)
Base
Case
2004
(
v.
2.1.9).
The
commenter
further
noted
that
the
major
changes
incorporated
into
EPA
Base
Case
2004
include
the
capital
costs
of
Selective
Catalytic
Reduction
(
SCR)
retrofits,
its
gas
price
forecast,
the
number
of
plants
available
to
switch
to
PRB
coal,
the
cost
and
performance
of
new
builds,
and
an
update
to
particulate
controls
on
existing
units.
However,
according
to
the
commenter,
EPA
has
left
unchanged
a
number
of
improbable
assumptions
that
several
commenters
raised
previously,
including:
the
load
9­
78
growth
rate
of
1.55
percent,
the
cost
and
performance
of
wet
Flue
Gas
Desulfurization
(
FGD)
($
201/
kW),
the
cost
and
performance
of
Activated
Carbon
Injection
(
ACI)
and
ACI
and
Fabric
Filter
(
FF),
the
Hg
co­
benefits
of
FGD+
SCR,
the
Hg
emissions
modification
factors,
and
model
plant
aggregations
amongst
others.
Furthermore,
according
to
the
commenter,
as
EPA
did
not
mention
any
revision
to
the
way
coal
units
are
aggregated,
it
appears
EPA
still
plans
to
perform
MACT
policy
modeling
runs
without
the
capability
of
modeling
plant­
level
emission
constraints.
The
commenter
stated
that
this
model
plant
aggregation
change
is
of
particular
importance
when
analyzing
Mercury
MACT
regulations
that
are
implemented
on
a
plant
averaging
basis.
In
performing
its
IPM
modeling
analysis,
the
commenter
took
particular
care
to
represent
the
model
plants
in
IPM
along
physical
plant
lines
to
capture
the
interactions
that
may
occur
between
individual
units
at
the
plant
level.
The
commenter
believed
that
the
lack
of
this
resolution
in
the
EPA
analysis
(
as
well
as
analysis
by
other
parties
relying
on
the
EPA
version
of
IPM)
represents
a
fundamental
oversight
in
the
studies
performed.
The
commenter
referred
back
to
its
Confidential
Business
Information
(
CBI)
Comments
filed
in
March
2004
as
to
why
disaggregating
coal
units
to
the
plant
level
allows
for
more
realistic
assessments
of
plant­
level
emission
constraints.

Demand
And
Peak
Growth
The
commenter
noted
that
the
starting
point
for
the
EPA
Base
Case
2004
electric
load
growth
is
the
projections
from
the
reference
case
of
AEO
2004.
The
commenter
stated
that,
as
in
the
past,
EPA
reduced
demand
growth
levels
in
the
AEO
projection
to
account
for
voluntary
energy
efficiency
programs.
According
to
the
commenter,
the
average
annual
growth
rate
in
AEO
2004,
based
on
the
electric
sales
forecasts,
is
1.77
percent.
The
commenter
stated
that
EPA
revised
this
growth
rate
down
to
1.55
percent.
According
to
the
commenter,
this
results
in
a
final
calculated
growth
rate
that
is
unchanged
from
the
EPA
Base
Case
2003.
The
commenter
stated
that,
as
it
does
with
air
quality
modeling,
EPA
should
not
include
in
its
future
energy
demand
modeling
legislative
or
regulatory
provisions
that
have
not
already
been
adopted.
According
to
the
commenter,
at
a
minimum,
EPA
should
use
the
AEO
growth
rates
or
other
historically
based
growth
rates
in
its
reference
case
and,
if
necessary,
carry
out
sensitivity
runs
with
higher
and
lower
alternative
energy
growth
patterns
that
bound
potential
future
economic
growth
scenarios.
The
commenter
referred
back
to
its
CBI
Comments
filed
in
March
2004
as
to
why
the
load
growth
rate
it
uses
in
its
analysis
much
more
closely
reflects
reality.

The
commenter
stated
that
EPA's
lower
average
demand
growth
rates,
and
the
resultant
energy
consumption,
directly
impact
the
system
and
the
costs
of
regulation.
The
commenter
further
stated
that
the
CCAP,
in
a
number
of
sensitivities
based
on
the
EPA
CSA
scenario,
directly
uses
the
higher
average
annual
growth
rate
projected
by
AEO
2003.
The
commenter
noted
that
other
modeling
results
provided
in
the
NODA
utilize
higher
average
annual
growth
rates.
The
commenter
assumed
a
2.3
percent
annual
average
load
growth
rate
and
EEI
assumed
a
1.7
percent
average
annual
growth
rate.
According
to
the
commenter,
as
the
annual
energy
growth
rate
is
compounded
over
the
study
period,
a
relatively
small
difference
in
the
rate
has
enormous
implications
over
time.

Natural
Gas
Prices
Have
Been
Revised
Upwards,
But
Not
Enough
The
commenter
noted
that
the
EPA
Base
Case
2004
incorporates
a
higher
natural
gas
forecast,
with
the
Henry
Hub
wellhead
price
increasing,
in
1999
dollars,
to
$
3.16
in
2020
9­
79
compared
to
$
2.94
in
the
EPA
Base
Case
2003.
According
to
the
commenter,
this
revision
of
natural
gas
prices
better
represents
the
trajectory
of
natural
gas
prices
going
forward
as
evident
in
comparisons
with
the
other
natural
gas
forecasts
utilized
by
EIA
in
its
Annual
Energy
Outlook
(
AEO)
2003
and
2004,
as
well
as
in
the
other
models
submitted
by
the
commenter
and
the
EEI
in
their
comments.
According
to
the
commenter,
though
this
revision
has
shifted
the
natural
gas
supply
curve
upwards,
it
still
falls
well
below
the
other
forecasts
previously
mentioned.
The
commenter
noted
that
AEO
2003
predicts,
in
1999
dollars,
a
price
of
$
3.53
in
2020
and
the
difference
between
AEO
and
EPA
becomes
slightly
more
pronounced
with
a
price
of
$
4.03
in
2020
forecasted
in
AEO
2004.
The
commenter
further
noted
that
the
forecast
used
in
their
modeling
is
comparable
to
AEO
with
a
price
of
$
3.45
in
2020
while
EEI
reaches
$
4.13
in
2020.
The
commenter
referred
to
section
II
of
its
CBI
Comments
for
a
detailed
description
of
how
both
the
commenter
and
EPA
derive
their
natural
gas
prices
and
how
they
differ.
The
commenter
stated
that
gas
price
forecasts
are
important
in
analyses
such
as
these
as
less
expensive
gas
prices
artificially
alleviate
the
pressure
on
coal
units
to
generate,
and
exaggerate
the
ease
of
which
the
system
can
inexpensively
rely
on
new
gas­
fired
generation
to
make
up
the
shortfall.
The
commenter
further
stated
that
over
the
past
12
to
24
months,
various
federal
agencies
and
committees
have
investigated
the
short­
and
long­
term
implications
of
natural
gas
usage
and
price
projections.
According
to
the
commenter,
EPA
has
not
provided
a
comparison
of
its
estimates
to
other
federal
findings
which
show
significantly
higher
prices
and
decreasing
domestic
supply.
The
commenter
stated
that
EPA's
final
analysis
of
the
impact
of
these
rules
should
include
a
range
of
natural
gas
price
forecasts
based
on
potential
real
world
implications
if
EPA's
overly
optimistic
assumptions
do
not
come
true.

The
commenter
has
noted
that
historical
gas
prices
have
been
volatile,
but
have
been
consistently
higher
then
forecasts
made
by
EPA,
a
trend
especially
evident
when
comparing
the
gas
prices
EPA
used
during
the
late
1990s
for
analyzing
the
impact
of
SIP
Call
regulation
on
the
industry.
The
commenter
noted
that
the
table
below
compares
recent
forecasts
made
by
EPA
to
historical
gas
prices.
According
to
the
commenter,
from
2000
through
2004
these
periods
overlap.
The
commenter
stated
that
it
is
worth
noting
that
when
comparing
actual
2000­
2004
historical
data
to
that
forecast
by
EPA
in
its
1995
and
1998
assumptions,
actual
prices
were
approximately
$
4.29/
MMBtu,
while
the
average
of
EPA's
forecast
over
that
same
time
period
results
in
a
price
of
less
than
$
2.00/
mmBtu
 
a
difference
of
over
100
percent.

Higher
SCR
Capital
Cost
Assumption
The
commenter
stated
that
in
the
case
of
unit
retrofit
costs,
especially
SCR
costs,
the
differences
between
EPA's
estimates
and
the
commenter's
actual
experience
is
quite
substantial.
The
commenter
stated
that
in
the
new
EPA
2004
(
v.
2.1.9)
assumptions,
EPA
increased
its
capital
cost
assumption
of
SCRs
from
$
62/
kW
to
$
83/
kW
(
for
a
representative
500
MW
unit).
While
the
commenter
believed
this
move
is
in
the
right
direction,
it
does
not
come
close
to
reflecting
the
actual
costs
of
retrofitting
such
devices
on
existing
generating
units.
The
commenter's
estimates
for
SCR
costs
were
developed
through
the
knowledge
and
experience
gained
during
nine
SCR
retrofit
projects
totaling
6,000
MW
of
capacity.
The
commenter
stated
that
these
actual
costs
for
compliance
with
the
NO
x
SIP
Call
have
been
provided
to
their
state
utility
regulatory
commissions
for
review
and
approval.
In
May
2004,
the
commenter's
regulated
utility
subsidiary
in
Indiana,
PSI
Energy,
received
approval
of
these
same
NOx
pollution
control
retrofit
costs.
The
commenter
stated
that
EPA
apparently
has
not
verified
its
NOx
control
cost
information
by
9­
80
comparing
it
with
the
most
recent
state
utility
regulatory
commission
cost
recovery
filings
in
states
which
have
recently
implemented
the
NO
x
SIP
Call.
The
commenter
also
stated
that
it
should
be
noted
that
the
large
number
of
SCRs
retrofitted
as
a
result
of
the
SIP
Call
represents
the
more
cost­
effective
(
i.
e.,
lower
capital
cost)
units.
The
commenter
added
that
EPA
apparently
has
not
considered
the
increasing
difficulty,
and
thus
the
higher
capital
cost,
of
retrofitting
increasingly
smaller
units
as
the
NO
x
caps
get
tighter.
The
commenter
referred
to
costs
documented
and
made
available
to
EPA
in
their
past
CBI
comments.

No
Changes
To
Cost
And
Performance
Of
Wet
FGD
And
ACI
and
FF
The
commenter
stated
that
with
the
updates
included
in
the
EPA
Base
Case
2004,
the
cost
and
performance
of
a
Wet
FGD
and
ACI
and
FF
remain
the
same.
According
to
the
commenter,
for
a
representative
500
MW
unit,
the
capital
cost
of
a
Wet
FGD
is
$
201/
kW
and
$
55/
kW
for
an
ACI
and
FF.
The
commenter
believed
these
capital
costs
continue
to
be
significantly
understated
and
emphasized
that
the
cost
assumptions
used
in
its
analysis,
as
documented
and
made
available
to
EPA
in
the
commenter's
CBI
Comments,
Section
V,
more
closely
represent
real­
world
retrofit
cost
levels
that
will
generally
be
experienced
by
the
utility
industry.
The
commenter
noted
that
these
retrofit
costs
were
derived
from
engineering
estimates
by
the
Chicago
firm,
Sargent
&
Lundy,
which
has
extensive
experience
in
the
design
and
application
of
these
technologies.

The
commenter
stated
that
while
the
generic
industry­
wide
cost
estimates
provided
in
their
past
CBI
comments
indicate
that
EPA
has
significantly
understated
compliance
costs,
more
recent
analyses
undertaken
by
the
commenter
provide
further
support
for
this
conclusion.
The
commenter
has
recently
started
construction
on
a
number
of
new
wet
FGD
projects
and
has
provided
more
refined
cost
estimates
to
the
Indiana
Utility
Regulatory
Commission
(
PSI
Energy
Cause
42622
and
42718)
identifying
the
Company's
projected
costs
for
complying
with
the
proposed
SO
2,
NO
x,
and
Hg
reduction
requirements.
According
to
the
commenter,
the
more
highly
refined
commenter­
specific
cost
estimates
provided
to
the
Indiana
Commission
show
costs
in
excess
of
the
generic
cost
projections
previously
provided
to
EPA
in
the
commenter's
CBI
Comments.
The
commenter
urged
EPA,
at
a
minimum,
to
use
their
more
representative
cost
estimates
for
pollution
control
retrofits
which
have
been
previously
provided.

The
commenter
stated
that
EPA
did
not
choose
to
update
the
emission
reduction
factors
associated
with
these
pollution
controls
from
those
assumed
in
the
EPA
Base
Case
2003
(
v.
2.1.6).
The
commenter
noted
that
on
a
unit
with
an
exiting
CESP
particulate
control,
EPA
continues
to
assume
that
a
Wet
FGD
burning
bituminous
coal
has
an
emission
reduction
factor
of
66
percent
compared
with
59
percent
assumed
by
the
commenter.
The
commenter
noted
that
the
co­
benefit
of
a
wet
FGD
combined
with
a
SCR
on
a
unit
burning
bituminous
coal
is
assumed,
by
EPA
to
result
in
a
90
percent
reduction
of
Hg.
This
is
higher
than
the
85
percent
co­
benefit
that
the
commenter
believed
is
achievable
and
sustainable,
and
has
particular
significance
regarding
the
stringency
of
an
Hg
policy
that
is
feasible
without
significant
additional
cost.
The
commenter
stated
that
this
difference
is
found
across
different
existing
particulate
controls
and
once
again
highlights
EPA's
more
aggressive
assumptions
for
cost
and
performance
of
retrofit
options.
The
commenter
stated
that
more
detailed
information
of
their
experience
of
the
actual
costs
of
these
pollution
control
technologies
can
be
found
in
Section
V
of
their
CBI
Comments.
According
to
the
commenter,
while
EPA
moderated
some
of
its
very
aggressive
assumptions
for
emission
reductions
factors
(
ERF's)
when
updating
from
the
EPA
Base
Case
2002
(
v.
2.1)
to
the
EPA
Base
9­
81
Case
2003
(
2.1.6),
the
commenter
believed
that
this
issue
should
have
been
readdressed
in
the
latest
update.
According
to
the
commenter,
based
on
recent
test
data,
EPA
acknowledges
the
difficulties
associated
with
the
still
overly­
aggressive
co­
benefit
assumptions
it
assumed
in
its
2003
and
2004
Base
Cases
(
v.
2.1.6
and
v.
2.1.9),
in
the
text
of
the
NODA
(
pg.
69871),
particularly
regarding
sub­
bituminous
coals.
The
commenter
stated
that,
for
example,
for
a
unit
configured
with
a
coldside
ESP
and
with
a
FGD
and
SCR,
EPA
recommends
changing
the
ERF
from
66
percent
to
16
percent.
The
commenter
believed
that
these
updates
should
be
incorporated
into
any
future
EPA
modeling
as
they
reflect
actual
results
at
test
units.
The
commenter
also
noted
that
these
changes
will
have
a
significant
impact
on
the
Hg
reduction
levels
that
can
be
achieved
through
co­
benefits,
and
therefore
the
cost
of
attaining
Hg
reductions
system­
wide.

The
commenter
stated
that
one
clarifying
point
must
be
made
regarding
their
assumption
of
ACI
availability.
The
commenter
further
stated
that
in
the
EPA
NODA,
Section
4,
part
D,
EPA
states
that
for
the
commenter's
other
modeled
scenarios,
including
a
MACT
scenario,
it
assumed
ACI
would
be
available
in
2005.
The
commenter
stated
that
this
is
factually
incorrect.
According
to
the
commenter,
they
modeled
the
availability
of
ACI
beginning
in
2007
for
its
policy
scenarios,
but
believed
that
widespread
commercial
availability
of
ACI
is
not
likely
before
2010.

Other
Major
Assumptions
The
commenter
stated
that
EPA
recognizes
the
need
for
regular
updating
of
model
inputs
to
keep
up
with
changing
energy,
environmental
and
macroeconomic
markets
and
understanding
of
future
conditions.
The
commenter
further
stated
that,
however,
EPA
has
not
taken
this
process
to
the
next
logical
step
which
is
an
analysis
of
the
accuracy
of
the
models
output.
The
commenter
noted
that
in
the
case
of
air
quality
modeling
the
EPA
has
detailed
guidance,
Guideline
for
Air
Quality
Models,
Appendix
W
(
July
2003)
40
CFR
Part
51
on
the
application
of
models
and
testing
the
models
output
against
known
actual
air
quality
measurements
and
conditions.

The
commenter
pointed
out
that
the
true
test
of
a
model's
capabilities
is
when
its
output
compares
favorably,
within
an
acceptable
confidence
interval,
to
actual
observed
data.
According
to
the
commenter,
neither
in
this
most
recent
IPM
modeling
nor
in
any
case
prior
to
that
has
EPA
ever
provided
information
about
how
the
IPM
modeling
output
compares
to
representative
known
energy
or
environmental
outcomes
in
the
real
world.
The
commenter
stated
that
in
this
most
recent
reference
case
modeling
EPA
skips
over
the
recent
historical
years
and
the
current
year
and
does
not
even
provide
any
model
output
results
until
2007.
The
commenter
further
stated
that,
thus,
affected
sources
have
no
way
of
checking
the
reliability
of
the
models
input
assumptions
or
output
when
compared
against
historical
or
recent
actual
energy
prices,
allowance
prices
or
SO
2,
NO
x
or
Hg
emissions.
The
commenter
added
that
these
uncorroborated
national,
state
or
plant
level
emissions
are
the
same
emissions
that
are
then
used
as
inputs
into
the
air
quality
models
that
EPA,
and
in
some
cases
state
regulatory
agencies,
use
to
evaluate
in­
state
source
impacts
as
well
as
significant
contribution
impacts
of
long
range
interstate
transport.
The
commenter
stated
that,
thus,
affected
sources
and
decision­
makers
have
no
basis
for
quantifying
the
accuracy,
precision
and
sensitivity
of
the
model
to
changes
in
model
assumptions
and
ultimately
in
making
emission
control
policy
decisions.
The
commenter
recommended
that
EPA
provide
an
evaluation
of
the
IPM
model
based
on
a
systematic
performance
evaluation
of
a
wide
range
of
temporal
and
spatial
outputs
using
current
real
world
model
inputs.
9­
82
Table
1
details
the
major
assumptions
across
each
of
the
modeling
described
in
the
comments
submitted
by
the
commenter,
CCAP,
CATF,
and
EEI.
The
following
section
will
lay
out
the
implications
of
these
assumptions
on
the
results
from
these
different
modeling
comments.

Table
1
Category
Commenter
5404
EPA
(
v.
2.1.6)
EPA
(
v.
2.1.9)

Source
Commenter
Assumptions
Document
02.03.04
EPA
Assumptions
Updates
v.
2.1.6,
July
2003
EPA
Assumptions
Updates
v.
2.1.9,
October
2003
Energy
and
Peak
Demand
(
natl
avg)
2.3%
Demand
Growth,
2.2%
Peak
Growth
1.55%
Demand
and
Peak
Growth
no
changes
from
2.1.6
SO
2
Control
Cost
and
Performance
500MW
=
$
276/
kW
(+
adders
for
MACT
&
timing)
500MW
=
$
201/
kW
no
changes
from
2.1.6
Nox
Control
Cost
and
Performance
(
SCR)
500MW
=
$
194/
kW
500MW
=
$
62.15/
kW
500MW
=
$
82.27/
kW
SO
2
and
NOX
Controls
for
Mercury
SCR+
FGD
85%
Hg
co­
benefit
(
bit
with
CESP)
SCR+
FGD
average
90%
Hg
co­
benefit
(
bit)
no
changes
from
2.1.6
Mercury
Control
Cost
and
Performance
(
ACI
and
Fabric
Filter)
500MW
=
$
95/
kW
500MW
­
$
55/
kW
no
changes
from
2.1.6
Reference
Gas
Price
Forecast
(
Henry
Hub)
2005­$
3.92,
2010­
$
3.66,
2015­$
3.49,
2020­$
3.54
2005­$
2.89,
2010­
$
2.97,
2015­$
2.96,
2020­$
2.94
2010­$
3.20,
2015­
$
3.25,
2020­$
3.16
PRB
Fuel
Switching
Capital,
FO&
M,
and
VO&
M
PRB
adders
into
3
separate
size
categories.
Additional
Adders
for
heat
rate
penalty
and
5
yr
amortization
(
amortization
CSA
only)
$
50/
kW
adder
increased
#
of
plants
available
$
50/
kW
adder
Capital
Charge
Rate
(
CCR)
and
Discount
Rates
(
DR)
DR
=
7.1%,
CCR
=
13.6%(
retrofits)
DR
=
5.34%,
CCR
=
12.0%(
retrofits)
no
changes
from
2.1.6
Cost
and
Performance
of
New
Builds
Commenter
cost
and
performance
for
gas
units,
ICF
cost
and
performance
for
coal
units
Updated
According
to
AEO
2003
Updated
According
to
AEO
2004
Category
Commenter
5404
EPA
(
v.
2.1.6)
EPA
(
v.
2.1.9)

Source
Commenter
Assumptions
Document
02.03.04
EPA
Assumptions
Updates
v.
2.1.6,
July
2003
EPA
Assumptions
Updates
v.
2.1.9,
October
2003
9­
83
Mercury
EMF
EMF
based
on
ICR
data
for
all
non
commenter
units.
Commenter
specified
EMFs
for
commenter
units.
Updated
Attachment
K.
Changes
made
to
all
types,
most
significantly
to
cobenefits
for
SNCRs
and
wet
FGDs.
no
changes
from
2.1.6
Plant
Aggregation
Model
plant
along
physical
lines
Model
Plant
Model
Plant
Model
Run
Years
2004,
2006,
2007,
2008,
2009,
2011,
2015,
2020
2005,
2010,
2015,
2020
2005,
2010,
2015,
2020
Table
1
(
has
different
headings)
Category
CCAP
CATF
EEI
(
CRA)
Source
EPA
Assumptions
v.
2.1.6,
July
2003
EPA
Assumptions
Updates
v.
2.1.6,
July
2003
EEI
Assumptions
Energy
and
Peak
Demand
(
natl
avg)
EPA
Assumptions
Updates
v.
2.1.6,
July
2003,
AEO
2003:
1.8%
Demand
and
Peak
Growth
1.55%
Demand
and
Peak
Growth
1.8%
Demand
Growth,
1.95%
Peak
Growth
SO
2
Control
Cost
and
Performance
(
Wet
FGD)
500
MW
=
$
201/
kW
500
MW
=
$
201/
kW
500
MW
=
$
201/
kW
Nox
Control
Cost
and
Performance
(
SCR)
500MW
=
$
62.15/
kW
500MW
=
$
62.15/
kW
500MW
=
$
62.15/
kW
SO
2
and
NO
X
Controls
for
Mercury
SCR+
FGD
average
90%
Hg
co­
benefit
(
bit)
SCR+
FGD
average
90%
Hg
co­
benefit
(
bit)
SCR+
FGD
average
85%
Hg
co­
benefit
(
bit)
Mercury
Control
Cost
and
Performance
(
ACI
and
Fabric
Filter)
500MW
~
$
55/
kW
500MW
~
$
55/
kW
500MW=$
41.29/
kW
Reference
Gas
Price
Forecast
(
Henry
Hub)
Various
Scenarios
used
the
following
assumptions:
1)
EPA
(
v2.1.6)
2)
AEO
2003,
2005­$
2.88,
2010­
$
3.29,
2015­$
3.55,
2020­$
3.69
2005­$
2.89,
2010­
$
2.97,
2015­$
2.96,
2020­$
2.94
2004­$
4.98,
2010­
$
3.33,
2015­$
4.06,
2020­$
4.13
Category
CCAP
CATF
EEI
(
CRA)
Source
EPA
Assumptions
v.
2.1.6,
July
2003
EPA
Assumptions
Updates
v.
2.1.6,
July
2003
EEI
Assumptions
9­
84
PRB
Fuel
Switching
$
50/
kW
adder
$
50/
kW
adder
50%
annual
limit
for
noncurrent
PRB­
fired
units
CCR
and
Discount
Rates
(
DR)
DR
=
5.34%,
CCR
=
12.0%(
retrofits)
DR
=
5.34%,
CCR
=
12.0%(
retrofits)
DR
=
6.05%,
CCR
=
13.32%(
retrofits)
Cost
and
Performance
of
New
Builds
Updated
according
to
AEO
2003
Updated
According
to
AEO
2003
Updated
According
to
AEO
2004
Mercury
EMF
Updated
Attachment
K.
Changes
made
to
all
types,
most
significantly
to
co­
benefits
for
SNCRs
and
wet
FGDs.
Updated
Attachment
K.
Changes
made
to
all
types,
most
significantly
to
co­
benefits
for
SNCRs
and
wet
FGDs.
Hg
co­
benefits
based
on
EPA's
1999
ICR
data.
ACI
assumptions
from
EPRI
Plant
Aggregation
Model
plant
Model
Plant
Unit
Groups
Model
Run
Years
2005,
2010,
2015,
2020
2005,
2010,
2015,
2020
2004,
2008,
2010,
2012,
2015,
2018,
2020
The
commenter
reviewed
the
modeling
results
provided
to
EPA
by
other
parties
during
the
comment
period.
The
commenter
noted
that
the
majority
of
parties
filing
power
sector
modeling
results
seem
to
agree
that
demand
growth
and
natural
gas
price
assumptions
used
by
EPA
warrant
modification,
and
so
use
assumptions
from
other
sources
in
their
model
runs.
The
commenter
stated
that
it
is
extremely
important
to
emphasize
that
in
long­
term
planning
models,
such
as
the
IPM
model
used
by
the
parties
to
analyze
the
cost
of
new
regulations,
model
input
assumptions
regarding
demand
growth
and
natural
gas
prices
dramatically
affect
overall
costs
of
regulation.
The
commenter
stated
that
these
assumptions
should
be
further
considered
by
EPA
as
it
proceeds
with
its
rulemaking.
The
commenter
provided
comments
on
some
individual
party
modeling
as
indicated
below.

Modeling
Results
Provided
by
CCAP
The
commenter
stated
that
CCAP
produced
more
than
a
dozen
runs
that
seem
to
demonstrate
that
timing
and
stringency
of
Hg
caps
have
little
bearing
on
the
cost
of
regulation.
The
commenter
also
stated
that
it
should
be
noted
that
the
runs
performed
by
CCAP
were
based
on
the
EPA
modeling
runs
that
analyzed
the
proposed
Clear
Skies
Amendments
and
do
not
specifically
model
the
CAIR
rule
as
proposed.
The
commenter
stated
that
the
results
are
therefore
not
directly
comparable
to
any
of
the
modeling
analyses
performed
by
EPA
in
the
course
of
this
rulemaking.
The
commenter
therefore
focused
its
comments
on
the
conclusion
that
timing
and
stringency
of
Hg
caps,
in
general,
are
not
very
significant.

The
commenter
stated
that
it
would
be
reasonable
to
expect
that
the
timing
of
a
Hg
cap
would
not
be
very
significant
if
two
things
could
be
assumed:
(
1)
The
implementation
of
the
initial
Hg
cap
coincides
with
any
new
SO
2
and
NO
x
regulations
 
so
that
Hg
reduction
benefits
resulting
9­
85
from
the
installation
of
scrubbers
and
SCRs
are
available
for
complying
with
the
Hg
policy,
and
(
2)
There
is
sufficient
time
to
install
all
compliance
options
(
and
compliance
options
are
commercially
available)
before
the
policy
takes
effect.
The
commenter
stated
that,
unfortunately,
neither
can
be
assumed
in
this
case.
The
commenter
noted
that
under
the
MACT
policy
that
EPA
proposes,
Hg
regulation
would
be
introduced
two
years
before
new
regulations
for
SO
2
and
NO
x
take
effect.
The
commenter
stated
that
this
would
result
in
unnecessary
costs
as
coal
units
would
need
to
comply
with
the
Hg
policy
before
controlling
for
SO
2
and
NO
x
 
lessening
the
ability
of
FGD
and
SCR
co­
benefits
to
reduce
the
burden
of
Hg
regulation.
The
commenter
further
stated
that
CCAP's
results
do
not
show
this
result
because
it
modeled
a
different
policy
 
Clear
Skies
 
which
requires
new
NOx
controls
to
be
in
place
fully
two
years
before
Hg
regulations
take
effect
(
2008
vs
2010),
and
SO
2
controls
to
be
in
place
at
the
same
time
Hg
regulations
take
effect.
According
to
the
commenter,
similarly,
CCAP
avoided
genuine
concerns
over
when
ACI
controls
would
become
commercially
available
(
the
commenter
does
not
expect
wide
availability
before
2010)
and
how
quickly
the
U.
S.
coal
fleet
could
be
outfitted
with
ACI,
FGD,
and
SCR
controls
by
assuming
everything
would
be
universally
available
from
the
beginning
of
the
run.
The
commenter
stated
that,
therefore,
any
claim
that
timing
does
not
matter
is
erroneous,
predicated
on
modeling
CSA
as
opposed
to
the
relevant
policies,
and
being
over­
optimistic
about
the
availability
of
controls.

The
commenter
stated
that,
likewise,
it
would
be
reasonable
to
expect
that
the
stringency
of
Hg
caps
would
not
be
significant
if
the
cost
of
installing
controls
is
low,
the
effectiveness
of
those
controls
is
high,
and
the
cost
of
substituting
options
other
than
coal­
fired
generation
is
modest.
The
commenter,
however,
believed
the
cost
of
retrofits
to
be
much
greater
than
the
estimates
of
CCAP,
which
used
EPA
assumptions,
especially
for
the
smaller
units
that
would
become
the
price­
setting
units
as
the
caps
were
made
more
stringent.
The
commenter
also
believed
Hg
EMFs
to
be
larger
(
i.
e.,
the
reductions
smaller),
and
the
cost
of
natural
gas
to
be
greater
 
which
both
increases
the
need,
and
the
cost,
of
switching
from
coal­
fired
generation
to
meet
more
stringent
caps.
It
is
the
commenter's
belief
that
more
stringent
caps
would
not
be
possible
without
greatly
increasing
the
cost
burden
of
Hg
regulation.

Modeling
Results
Provided
By
CATF
The
commenter
noted
that
the
Clean
Air
Task
Force
("
CATF")
performed
two
runs
using
EPA
assumptions.
The
commenter
stated
that
the
first
run
shows
CAMR
MACT
plus
CAIR
using
EPA
assumptions,
which
allows
for
a
relatively
direct
comparison
with
the
commenter's
model
results
for
CAMR
MACT
plus
CAIR.
According
to
the
commenter,
from
this
comparison,
it
is
clear
that
EPA
assumptions
allow
more
pollution
controls
to
be
installed
at
lower
costs
than
the
commenter's
assumptions
allow
 
reducing
the
cost
of
regulation.

The
commenter
stated
that
the
second
run
provided
by
CATF
shows
that
EPA
assumptions
allow
for
a
much
more
stringent
MACT
rate
while
significantly
increasing
regulatory
costs
by
about
30
percent.
The
commenter
further
stated
that
this
result
is
predicated
on
FGD
and
SCR
combinations
providing
the
90
percent
reduction
needed
for
the
stringent
MACT
for
both
bituminous
and
sub­
bituminous
coal
units.
The
commenter
maintained
that
it
is
unlikely
that
an
FGD
and
SCR
combination
could
be
depended
on
to
meet
such
a
strict
standard,
particularly
for
units
burning
sub­
bituminous
coal.
9­
86
Modeling
Results
Provided
By
EEI
The
commenter
stated
that
EEI
runs
adopt
the
industry's
view
on
FGD
and
SCR
co­
benefits
and
other
Hg
emission
factors,
and
therefore
show
higher
annual
Hg
emissions
under
MACT
policies
than
EPA
assumptions
produce.
The
commenter
added
that,
in
fact,
EEI's
forecast
for
emission
levels
are
very
similar
to
the
emission
levels
shown
in
the
commenter's
filing.
The
commenter
further
added
that
even
so,
it
could
be
said
EEI's
runs
do
not
go
far
enough.
The
commenter
believed
EEI's
assumptions
for
costs
of
emission
control
equipment
were
comparable
to
EPA's
cost
estimates.
The
commenter
states
that
while
energy
demand
growth
assumptions
were
marginally
increased
from
EPA's
starting
point,
the
growth
rate
is
still
fully
one­
third
below
historical
growth
and
far
below
what
is
likely
to
occur
over
the
forecast
period.
The
commenter
further
states
that
these
assumptions
serve
to
significantly
reduce
EEI's
estimates
of
regulatory
costs.

The
commenter
stated
that,
in
sum,
there
are
significant
issues
with
the
assumptions
used
by
the
other
commenters
in
their
modeling
analyses,
resulting
in
overly
optimistic
projections
regarding
control
costs
and
achievability
of
reductions.
Based
on
the
foregoing,
the
commenter
submitted
that
its
assumptions
are
the
most
realistic
and
that
its
modeling,
therefore,
most
accurately
predicts
the
costs
of
the
proposed
rule
as
well
as
the
achievability
of
the
proposed
timing.
The
commenter
stated
that
EPA's
final
rule
should
include
a
series
of
analyses
that
factor
in
assumptions
comparable
to
the
commenter's
assumptions.

Response:

EPA
appreciates
the
commenters
suggestions.
A
complete
discussion
of
EPA's
modeling
of
costs
and
energy
impacts
can
be
found
in
Chapter
7
of
the
Regulatory
Impact
Analysis.
EPA
also
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
ample
evidence
suggests
that
Activated
Carbon
Injection
(
ACI)
and
other
Hg
control
options
are
already
commercially
available.
See
Document
ID
No.
OAR­
2002­
0056­
3454
(
Institute
of
Clean
Air
Companies
Comments);
and
No.
OAR
2002­
0056­
2888
(
NESCAUM
Comments).
The
commenter
stated
that
given
the
evidence
of
commercial
availability,
EPA
has
not
adequately
explained
its
conclusion
that
ACI
will
not
be
available
for
commercial
application
until
after
2010.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
9­
87
Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
ACI
or
a
similar
Hg­
specific
control
technology
will
be
necessary
to
meet
any
of
the
lower
caps
(
i.
e.,
beyond
co­
benefit
reductions)
under
consideration
(
e.
g.,
EEl's
2015
cap
or
EPA's
2018
cap).
However,
many
commenters
have
advocated
that
the
allowance
allocation
adjustment
factors
for
EPA's
proposed
Phase
I
2010
cap
(
or
allowance
adjustment
factors
proposed
by
others)
continue
on
into
later
stages
of
the
Hg
program.
Cinergy
has
stated
that
such
allocation
preferences
should
end
with
any
cap
beginning
in
2015.
The
commenter
agrees
with
Cinergy's
position
on
this
issue.

Response:

The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
determining
unit­
level
allocation
under
EPA's
example
allocation
methodology
for
States.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
ACI
will
be
available
for
initial
application
by
2010
and
for
widespread
commercial
application
by
2012­
2015.
EPA
has
staked
its
decision
to
lower
the
cap
beyond
co­
benefits
on
its
expectation
that
"
ACI
technology
would
be
available
for
commercial
application
after
2010
and
that
removal
levels
in
the
70
percent
to
90
percent
range
could
be
achievable."
It
is
noteworthy
that
all
of
the
modeling
that
EPA
highlights
in
the
NODA
assumes
some
availability
of
ACI
by
2010.
In
a
July
20,
2004
report
to
EPA
by
DOE
officials
responsible
for
development
of
Hg­
specific
control
technologies
such
as
ACI,
DOE
concluded
"
ACI
works,"
but
needs
further
demonstration,
now
underway,
to
be
commercially
available
by
2010­
2012.
Hence,
there
is
little
question
about
the
technology
becoming
available
for
all
coal
ranks.

The
commenter
believed
that
the
issue
of
levels
of
control
with
ACI
among
coal
ranks
must
be
addressed.
DOE
reports
that
its
near
term
goals
remain
to
demonstrate
50­
70
percent
reduction
on
bituminous
coals
by
2005
and
on
lower
ranks
coals
by
2007.6
Thus,
DOE's
near
term
goals
do
not
show
any
variation
by
coal
rank,
and
the
later
demonstration
date
of
2007
for
lower
rank
coals
is
irrelevant
for
post
2014
application.
To
date,
there
is
no
basis
to
believe
that
DOE
will
not
achieve
its
stated
goals.
As
referenced
in
the
NODA,
early
pilot
testing
of
a
COHPAC
system
on
a
bituminous
unit
(
Gaston)
showed
longer­
term
testing
removals
of
78
percent,
and
ACI
(
not
COHPAC)
testing
at
a
subbituminous
coal­
fired
unit
(
Pleasant
Prairie)
showed
longer­
term
testing
removals
in
the
range
of
60­
70
percent.
Testing
at
two
other
bituminous
plants
(
Salem
Harbor
and
Brayton
Point)
showed
longer­
term
removals
at
higher
levels,
although
there
are
some
concerns
about
whether
either
of
these
units
is
sufficiently
representative
for
replication.
9­
88
In
its
July
report
to
EPA,
DOE
further
states
that
its
longer­
term
goal
is
to
demonstrate
emission
reductions
of
90
percent
by
2010.
However,
in
the
July
presentation,
its
current
projection
("
DOE
estimate
for
performance
potential
with
ACI")
for
ACI/
COHPAC
is
80
percent
removal
for
a
CS­
ESP
bituminous
unit,
70
percent
removal
for
CS­
ESP
and
CS­
ESP/
FGD­
Dry
subbituminous
units,
and
70
percent
removal
for
all
lignite
units
(
except
that
HS­
ESP/
FGD
lignite
units
increase
to
83
percent).
It
is
these
DOE
projections
upon
which
EPA
is
basing
its
proposed
decision
to
implement
a
cap
significantly
lower
than
co­
benefits.

Based
upon
this
information,
the
commenter
believed
that
EPA
must
evaluate
the
equities
of
allowance
allocation
adjustments
among
coal
ranks
for
post
co­
benefits
caps.
The
first
risk
to
evaluate
is
technology/
compliance
risk.
There
is
a
risk
that
the
as
yet
unproven
technologies
upon
which
DOE
relies
will
not
work
well,
or
will
not
work
well
at
the
levels
predicted.
However,
this
risk
is
generally
equal
among
all
coal
ranks.
The
DOE
currently
has
41
field
tests
underway
which
will
be
completed
by
2007.
Of
these
41
tests,
27
involve
subbituminous
or
lignite
coals.
These
extensive
tests,
the
majority
of
which
concentrate
on
low­
rank
coals,
indicate
that
DOE
will
be
able
to
achieve
its
stated
removal
targets
within
the
given
timeframes.
However,
no
coal
rank
has
any
more
of
guarantee
that
this
will
in
fact
come
to
pass
than
any
other.

The
commenter
added
that
there
has
been
short­
term
testing
is
true
for
all
coal
ranks,
and
the
fact
that
there
might
be
a
few
more
short­
term
field
tests
for
bituminous
coal
would
seem
to
make
little
overall
difference
in
technology/
compliance
risk
because
there
has
been
no
substantial
testing
beyond
short­
term
field
tests
for
any
coal
rank.
Hence,
the
technology
risks
associated
with
DOE
meeting
its
stated
control
technology
goals
remain
equal
among
coal
ranks.

The
commenter
also
noted
that
there
is
no
greater
compliance
risk
for
any
coal
rank
because
each
coal
rank
has
an
available
"
backstop"
technology
that
will
allow
it
to
comply.
Bituminous
units
can
install
FGD
to
reach
60
percent
removals,
and
subbituminous
units
can
install
FF
to
reach
65
percent
removal
(
CRA
2004
EMFs).
The
commenter
did
not
believe
there
is
any
plausible
basis
to
mandate
these
control
technologies
now
solely
for
Hg
removal,
as
EPA
has
concluded,
when
developing
Hg­
specific
control
technologies
show
such
promise
and
greater
cost­
effectiveness.
However,
that
conclusion
becomes
less
appropriate
for
any
post­
cobenefits
caps.
In
the
event
that
technology
risk
impacts
one
coal
rank
but
not
another
in
the
compliance
year,
either
coal
rank
has
an
available
backstop
compliance
option,
and
therefore
compliance
risk
remains
equal
among
coal
ranks
for
the
later
caps
and
cannot
justify
application
of
any
allowance
allocation
factors
(
the
fact
that
the
backstop
technology
for
either
coal
rank
may
cost
more
than
an
ACI­
based
alternative
is
not
a
relevant
basis
to
adjust
allocations
because
both
subbituminous
and
bituminous
coal
users
share
equal
technology
development
risk
ACI,
and
their
backstop
technologies
are
both
within
the
same
range
of
cost­
effectiveness)
.

Based
on
the
above
information,
the
commenter
believed
that
EPA
clearly
cannot
support
an
allocation
adjustment
ratio
whereby
bituminous
coal
is
assigned
a
factor
of
1
and
lower
ranks
coals
are
assigned
higher
factors
for
post
co­
benefits
caps
because
that
approach
assumes
that
bituminous
coals
have
no
technology
compliance
risk,
and
that
lower
rank
coals
have
greater
technology/
compliance
risk,
which
is
simply
not
true.
As
well,
an
allocation
ratio
of
1.25
for
subbituminous
and
3
for
lignite,
and
seemingly
derived
for
a
co­
benefits
approach,
bears
no
relationship
to
whatever
differing
levels
of
risk
might
be
perceived
among
the
coal
ranks
for
Hg­
specific
control
technologies
that
have
not
been
commercially
deployed
(
the
control
9­
89
differences
are
nominal
(
10
percent)
and
do
not
warrant
those
allocation
ratios).
Thus,
there
is
nothing
that
is
either
"
directionally
correct"
or
"
equitable"
in
awarding
extra
allowances
to
low
rank
coals
that
bears
any
relationship
to
the
technical
and
compliance
risks
among
coal
ranks
for
post
co­
benefits
caps.

Response:

EPA
appreciates
the
commenters
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
EPA's
IPM
modeling
assumption
for
ACI
are
based
on
EPA's
Office
of
Research
and
Development
(
ORD)
assessment.
Although
modeled
in
IPM
to
be
available
immediately
for
all
coal­
fired
generation
as
a
simplification
of
modeling,
ORD
assessment
concluded
that
ACI
could
not
be
fully
deployed
on
all
plants
by
2010
timeframe.

The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
determining
unit­
level
allocation
under
EPA's
example
allocation
methodology
for
States.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
noted
that
there
is
a
10
percent
difference
between
DOE's
removal
targets
for
ACI
applied
to
bituminous
coal
(
80
percent)
and
the
lower
rank
coals
(
70
percent)
(
all
ranks
share
an
equal
risk
that
these
levels
will
not
be
achieved
in
practice).
The
difference
between
these
controls
levels
is
both
small
(
10
percent)
and
equal
to
or
above
the
nominal
required
reduction
(
an
aggregate
70
percent
reduction
in
Hg
for
EPA's
15­
ton
cap).
The
commenter
was
not
aware
of
any
compelling
reason
to
subsidize
low
rank
coal
users
that
may
have
nominally
different
control
costs.
Nor
is
the
commenter
aware
of
any
compelling
reason
for
EPA
to
require
bituminous
coal
users
to
provide
that
subsidy
(
in
the
form
of
lost
allowances
due
to
allocation
ratios)
to
users
of
the
other
coal
ranks.

The
commenter
was
not
aware
of
any
policies
or
reasons
supporting
such
subsidy
because
they
appear
not
to
have
happened
under
similar
circumstances.
Thus,
the
commenter
is
not
aware
that
EPA
considered
subsidizing
bituminous
coal
under
the
CAIR
because
it
would
cost
users
of
that
coal
rank
significantly
more
to
meet
SO
2
caps
than
users
of
subbituminous
coal.
Nor
is
the
commenter
aware
that
EPA
considered
granting
bituminous
coal
users
extra
SO
2
allowances
under
CAIR
to
help
prevent
such
users
from
switching
to
subbituminous
coals
to
meet
their
SO
2
requirements.

For
similar
reasons,
the
commenter
found
no
plausible,
equitable
basis
for
awarding
such
subsidies
here.
If
the
market
finds
it
more
difficult
or
expensive
to
control
Hg
emissions
from
lower
rank
coals
than
from
bituminous
coals
it
will
decide
whether
to
buy
allowances
to
cover
9­
90
that
shortfall,
or
it
will
switch
coals,
which
is
how
it
resolved
control
issues
under
Title
IV
(
Acid
Rain)
of
the
Clean
Air
Act
Amendments
of
1990,
how
it
will
resolve
control
issues
under
CAIR,
and
how
it
should
resolve
control
issues
under
the
Hg
rule.

It
is
also
important
to
note
that
a
70
percent
Hg
reduction
for
subbituminous
coal
results
in
essentially
the
same
emissions
as
an
80
percent
reduction
on
bituminous
coal.
The
mean
Hg
content
in
subbituminous
coal
is
5.74
lb/
TBtu,
and
the
mean
Hg
content
for
bituminous
coal
is
8.59
lb/
TBtu.
If
Hg
emissions
from
each
coal
are
reduced
by
70
percent
and
80
percent
respectively,
the
resulting
Hg
emissions
are
1.722
lb/
TBtu
for
subbituminous
and
1.718
lb/
TBtu
for
bituminous
coal,
or
no
difference
at
all.
In
fact,
on
a
risk
basis,
the
less
homogeneous
nature
of
bituminous
coals
means
that
these
equal
aggregate
numbers
underestimate
the
greater
reduction
risk
associated
with
bituminous
coals.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
determining
unit­
level
allocation
under
EPA's
example
allocation
methodology
for
States.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
noted
that,
in
the
NODA,
EPA
presented
the
results
of
a
number
of
attempts
to
model
the
impact
and
costs
of
various
proposed
Hg
rules.
The
significant
divergence
in
the
modeling
results,
even
for
ostensibly
similar
regulatory
scenarios,
demonstrates
the
fundamental
problem
in
devising
this
rule
given
the
high
degree
of
uncertainty
in
the
model
inputs
and
assumptions.
It
argues
strongly
in
favor
of
the
commenter's
original
recommendation,
to
defer
setting
a
hard
cap
until
adequate
information
is
available
about
the
performance
and
cost
of
co­
benefit
and
Hg­
specific
control
technologies.

First,
the
commenter
did
not
believe
that
EPA's,
EEI's
or
Cinergy's
model
inputs
are
quite
right,
although
each
has
developed
appropriate
inputs
for
individual
components.
The
commenter
also
did
not
believe
that
EEI's
model
is
correct
because
it
has
apparently
assigned
little
or
no
cost
to
switching
to
subbituminous
coal
for
SO
2
compliance,
while
both
EPA
and
Cinergy
have
assigned
costs
to
that
action.
This
would
tend
to
underestimate
the
level
of
FGD
installation
needed
for
compliance
with
the
CAIR,
and
therefore
underestimate
co­
benefits.
Hence,
the
commenter
believes
that
either
EPA's
or
Cinergy's
inputs
on
the
cost
for
coal
switching
should
be
used,
and
generally
believes
that
Cinergy's
formula
presents
a
more
comprehensive
approach,
although
there
may
be
little
difference
in
results
between
Cinergy's
or
EPA's
inputs.

Next,
the
commenter
believed
that
EPA
has
significantly
underestimated
the
cost
of
9­
91
control
equipment.
This
would
tend
to
overestimate
the
number
of
FGD
units
that
would
be
installed
to
meet
the
CAIR,
and
hence
overestimate
co­
benefits.
The
commenter
also
believed
that
either
EEI's
numbers
or
Cinergy's
pollution
control
cost
numbers
better
reflect
current
reality.
These
two
variables,
plus
the
EMF
factors,
are
what
will
most
influence
the
final
estimate
of
co­
benefits
reductions,
cost
and
performance.
The
commenter
had
no
comment
on
growth
numbers.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
See
comment
response
above
for
EPA's
response
to
commenter's
criticism
of
EPA
modeling.
EPA
agrees
with
the
commenter
that
modeling
that
shows
costs
for
coal
switiching
is
a
better
representation
of
costs.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
in
order
to
respond
to
this
question,
it
is
important
to
define
what
is
meant
by
"
availability."
Four
stages
of
development
must
be
recognized
in
this
context:
(
1)
tests,
(
2)
demonstrations,
(
3)
commercially
available
at
individual
units,
and
(
4)
commercially
available
for
the
entire
utility
system.
For
a
nationwide
rulemaking
that
imposes
controls
on
the
entire
population
of
coal­
fired
boilers
in
this
nation,
commercial
availability
for
the
entire
system
of
boilers
in
this
nation
is
the
most
important
issue.

A
test
is
a
short­
term
evaluation
of
Hg
removal
as
a
function
of
different
variables,
such
as
injection
rate
of
activated
carbon,
flue
gas
temperature,
etc.
and
may
gather
information
for
a
few
hours
to
up
to
30
days.
A
test
might
identify
obvious
balance­
of­
plant
impacts,
but
not
subtle
impacts
that
will
require
more
operating
time.
In
the
context
of
the
ACI
work
completed
to
date,
the
commenter
considered
all
field
work
with
ACI/
ESP
to
be
tests.
A
demonstration
requires
one
to
two
years
of
operation,
including
an
assessment
of
impacts
on
the
plant
that
require
the
accumulation
of
significant
operating
hours.
Commercial
availability
at
a
unit
scale
is
where
a
utility
can
purchase
an
individual
or
limited
number
of
processes,
and
receive
credible
performance
guarantees.
Also,
unit
scale
Hg
controls
may
only
be
commercially
available
for
certain
boiler
types,
unit
configurations,
or
fuel
types.
The
purchaser
can
access
an
experience
base
assuring
risks
to
operation
are
commensurate
with
other
aspects
of
plant
operation
(
e.
g.,
the
process
does
not
risk
operations
any
more
than
usual
activities).
Finally,
commercial
availability
at
the
system
scale
requires
both
commercial
availability
at
the
unit
scale,
and
the
necessary
infrastructure
to
provide
reagents,
construction
material
and
manpower,
and
transport
of
key
process
requirements
for
the
entire
population
of
boilers.
System
availability
is
the
ultimate
goal
that
must
be
achieved
to
enable
broad
utilization
of
a
technology.

The
commenter
had
provided
an
estimate
of
the
availability
of
ACI
technology
for
each
of
these
four
stages
of
development.
The
earliest
that
any
technology
will
be
available
on
a
system
basis
is
2011
and
for
some
configurations
of
coal
type,
control
technology
and
Hg
reduction
level
availability
on
a
system
basis
will
not
be
achieved
until
2014.

Finally,
the
utility
industry
has
had
many
experiences
that
have
demonstrated
why
several
9­
92
years
of
demonstration
effort
are
required
before
a
new
control
technology
should
be
applied
broadly.
For
example,
hot­
side
ESPs
were
deployed
without
sufficient
experience
and
resulted
in
many
unanticipated
problems.
In
the
mid­
1970s,
the
first
hot­
side
ESP
applications
on
boilers
firing
western
low
sulfur
coal
found
persistent
particulate
matter
removal
shortfalls,
in
contrast
to
performance
predictions
and
guarantees
offered
by
suppliers.
Research
was
initiated
in
the
early
1980s
to
provided
an
explanation
of
this
behavior,
which
resulted
in
a
solution
five
years
after
the
problem
was
first
identified
and
long
after
these
ESPs
were
in
commercial
service.

This
experience
is
significant
for
ACI,
especially
in
applications
at
units
with
smaller
ESPS.
Carbon
particles
or
fly
ash
co­
mingled
with
carbon
may
quickly
accept
 
and
then
ultimately
lose
 
the
electrostatic
charge
so
that
a
certain
fraction
of
carbon
injected
could
be
released
from
the
plate
before
rapping,
to
be
either
re­
entrained
or
to
disturb
the
quiescent
zone
within
the
collection
hopper.
This
complication
has
not
been
observed
with
ACI
demonstrations
to
date
for
two
reasons.
First,
the
ESP
units
employed
in
the
demonstration
tests
exhibit
relatively
generous
specific
collecting
area
so
that
any
carbon
material
that
eludes
collection
in
the
first
few
fields
is
ultimately
collected
in
later
fields.
Second,
the
duration
of
tests
has
been
limited.
It
is
not
clear
how
long
it
will
take
to
establish
steady­
state
conditions
within
the
collected
ash
layer.
As
demonstrated
with
the
hot­
side
ESP
experience,
steady
state
conditions
with
respect
to
electrical
properties
of
the
entire
layer
of
ash
must
be
established,
not
simply
the
outer
layer
adjacent
to
the
flue
gas.

The
commenter
suggested
for
these
reasons,
it
would
be
imprudent
to
require
the
deployment
of
insufficiently
demonstrated
technologies
to
the
entire
population
of
coal­
fired
utility
boilers
and
to
potentially
jeopardize
the
reliability
of
the
electricity
supply
in
this
nation.

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

5.
EEI
estimated
that
ACI
would
be
less
expensive
per
pound
of
Hg
removed
than
EPA
estimated.
Cinergy
assumed
higher
capital
costs
for
ACI
than
EPA.
Are
EPA's
Hg
control
cost
assumptions
reasonable?
EPA
is
seeking
additional
detailed
data
addressing
the
validity
of
the
cost
assumptions
for
ACI.

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
noted
that
highly
effective
Hg
control
technologies
are
available
and
cost
effective.
Two
companies
that
supply
bromated
activated
carbon
injection
(
B­
ACI)
for
utility
power
plants
offer
removal
rate
guarantees.
The
ACI
industry
reports
that
there
is
a
sufficient
supply
of
activated
carbon
to
supply
the
anticipated
demand
for
Hg
control
by
the
regulated
industry.
More
than
800,000
tons
of
activated
carbon
are
currently
produced
worldwide
annually.
The
technology
has
proven
to
be
more
cost
effective
than
initially
thought
by
EPA.
The
cost
of
ACI
has
been
reported
to
be
ranging
between
$
2,000
and
$
20,000
per
pound
of
Hg
removed,
much
less
than
the
control
cost
of
$
50,000/
lb
that
was
considered
in
9­
93
the
proposed
rule.
The
B­
ACI
technique
has
reduced
the
amount
of
activated
carbon
necessary
to
create
the
same
effect.
By
reducing
the
amount
of
activated
carbon
needed
the
B­
ACI
technology
will
have
a
significant
impact
on
the
results
of
IPM
modeling
included
in
the
proposed
rule.
This
commenter
stated
that
the
impact
from
the
use
of
B­
ACI
will
serve
to
positively
enhance
the
economic
viability
of
Hg
control
under
MACT.
It
would
also
address
any
potential
concerns
regarding
sufficient
availability
of
activated
carbon.

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
stated
that
EPA
should
analyze
supply
and
price
response
to
demand
created
by
the
various
ACI
scenarios.
The
current
supply
of
activated
carbon
is
not
sufficient
to
accommodate
a
substantial
demand
from
the
utility
sector
and
it
could
take
up
to
five
years
to
bring
activated
carbon
production
facilities
on
line.

Response:

Given
that
the
first
phase
cap
is
set
at
the
Hg
co­
benefits
of
CAIR,
EPA
does
not
project
significant
amount
of
ACI
to
be
retrofitted
until
the
2018
timeframe.
With
regard
to
demand
for
activated
carbon,
EPA
notes
that
markets
respond
to
the
demand
for
materials,
much
like
under
the
NOx
SIP
call
supply
for
catalyst
increased
with
demand.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
October
2002,
in
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5488)
stated
that
halogen­
impregnated
sorbents
have
been
shown
to
dramatically
improve
the
effectiveness
of
sorbent
injection
systems,
particularly
for
sub­
bituminous
and
lignite
coals.
These
systems
are
also
commercially
available,
as
evidenced
by
the
fact
that
construction
of
the
subbituminous
coal­
fired
unit
4
of
MidAmerican
Energy's
Council
Bluffs
power
plant
is
moving
forward
under
a
permit
that
relies
on
their
use
or
use
of
an
equivalently
effective
control
method.
This
unit
was
permitted
with
the
condition
that
it
achieve
a
high
degree
of
Hg
reduction,
which
was
deemed
achievable
based
on
test
results
obtained
for
lignite
coal
with
iodine­
impregnated
carbon.

The
combination
of
sub­
bituminous
coal
with
a
spray
dryer
for
SO
2
removal
has
been
viewed
as
a
challenging
configuration
for
Hg
control,
because
the
spray
dryer
is
thought
to
remove
halogens
that
are
needed
to
enhance
Hg
capture
from
the
flue
gases.
However,
in
recent
tests
at
Sunflower
Electric's
Holcomb
Station,
77
percent
Hg
removal
was
achieved
through
injection
of
a
proprietary
halogen­
treated
sorbent
offered
by
NORIT
Americas,
at
a
very
low
injection
rate
of
just
0.7
lb/
MMacf.
The
cost
of
the
sorbent
was
just
$
0.65/
lb,
making
it
much
9­
94
more
cost
effective
than
either
iodine­
impregnated
carbon
or
injection
of
untreated
activated
carbon
(
at
higher
injection
rates).
Of
note,
rates
of
Hg
capture
at
the
Holcomb
Station
were
also
boosted
significantly
simply
by
blending
the
sub­
bituminous
coal
with
a
western
bituminous
coal
that
had
higher
chlorine
content.

Recent
test
results
achieved
with
brominated
powdered
activated
carbon
(
B*
PAC)
are
also
impressive.
B*
PAC
has
been
tested
at
seven
different
power
plants,
including
four
full­
scale
tests.
Mercury
removal
rates
ranged
from
70­
98
percent
across
a
wide
variety
of
coals
and
configurations.
Researchers
at
DOE
and
Sorbent
Technologies
Corp.
have
estimated
from
these
tests
that
with
B*
PAC
costing
about
$
0.75/
lb,
Hg
removal
costs
may
be
just
10­
20
percent
of
DOE's
baseline
estimates.

Full­
scale
tests
with
B*
PAC
have
recently
been
conducted
at
Detroit
Edison's
St.
Clair
Power
Plant,
which
typically
burns
85
percent
sub­
bituminous
coal
blended
with
15
percent
bituminous
coal
and
is
equipped
with
a
cold­
side
ESP.
Mercury
speciation
upstream
of
the
sorbent
injection
point
is
estimated
to
be
80­
90
percent
elemental
Hg.
Nevertheless,
Hg
removal
rates
of
90
percent
or
higher
were
achieved
with
B*
PAC
injection
rates
of
just
3
lb/
MMacf,
with
no
additional
control
equipment
required.
The
B*
PAC
vendor
estimates
that
with
cold­
side
ESP,
90
percent
removal
can
be
achieved
at
a
cost
of
less
than
$
9000
of
sorbent
per
pound
of
Hg
removed.
Moreover,
because
B*
PAC
injection
rates
are
so
low,
its
use
has
negligible
impact
on
characteristics
of
fly
ash
for
use
in
cement.

Environmental
Defense
and
Western
Resource
Advocates
have
produced
a
white
paper
entitled
Mercury
Air
Pollution:
The
Case
for
Rigorous
MACT
Standards
for
Subbituminous
Coal,
which
shows
that
there
is
no
technical
justification
for
a
separate
subcategory
of
Hg
MACT
standards
for
plants
burning
subbituminous
coal.
A
copy
of
this
paper
was
attached
to
our
June
29,
2004,
comments
and
is
incorporated
by
reference
herein.
Although
produced
more
than
a
year
ago,
that
paper
found
that
90
percent
Hg
reduction
is
achievable
at
effectively
the
same
costs
irrespective
of
whether
a
plant
burns
bituminous
or
subbituminous
coal
or
a
blend
of
the
two
(
as
is
common
practice),
using
activated
carbon
injection
and
either
a
fabric
filter
or
an
ESP
with
a
compact
baghouse
for
particulate
collection.

Since
that
paper
was
issued
in
May
2003,
many
advances
have
been
made
in
Hg
control
technologies.
These
technological
advances,
such
as
using
halogenated
sorbents
in
a
sorbent
injection
system,
advanced
dry
FGD,
ECO
technology,
or
even
simply
blending
some
higher
chlorine
bituminous
coal
at
subbituminous
or
lignite
fired
power
plants,
are
discussed
in
detail
above.
The
pilot
and
full
scale
tests
of
these
technological
improvements
continue
to
prove
that
high
levels
of
Hg
control
can
be
cost
effectively
achieved
at
all
coal­
fired
power
plants,
regardless
of
the
type
of
coal
burned.

As
mentioned
above,
the
Iowa
Department
of
Natural
Resources(
IDNR)
recently
imposed
an
emissions
limit
reflecting
83
percent
reduction
in
Hg
as
MACT
for
a
new
unit
burning
subbituminous
coal
at
MidAmerican
Energy's
Council
Bluffs
power
plant.
In
doing
so,
the
IDNR
relied
on
results
from
a
full­
scale
test
of
activated
carbon
injection
for
Hg
control
at
Great
River
Energy's
Stanton
Generating
Station,
which
burns
North
Dakota
lignite
coal.
Tests
at
Stanton
found
that
on
average
81
percent
Hg
removal
could
be
obtained
with
the
use
of
activated
carbon
and
a
spray
dryer/
baghouse
combination.
Moreover,
with
the
use
of
iodine­
impregnated
activated
9­
95
carbon,
97
percent
Hg
removal
efficiency
could
be
achieved.
The
IDNR
determined
that
the
subbituminous
coal
to
be
burned
at
the
Council
Bluffs
plant
was
similar
to
lignite
coal
in
terms
of
Hg
emissions,
and
thus
relied
on
the
Stanton
test
to
justify
the
MidAmerican
permit
limits.
Subsequent
tests
at
Stanton
with
B*
PAC
injection
and
the
spray/
dryer
baghouse
combination
have
demonstrated
nearly
90
percent
removal
with
only
1
lb/
MMacf
sorbent
injection,
at
an
estimated
cost
of
only
$
2500
per
pound
of
Hg
removed.
These
tests
demonstrate
that
the
Stanton
facility,
burning
lignite
coal,
could
easily
and
cost­
effectively
meet
an
emissions
limit
of
1
lb/
TBtu,
almost
a
factor
of
10
lower
than
EPA's
proposed
MACT
for
existing
lignite
facilities.

EPA's
proposal
to
set
disparate
standards
depending
on
rank
of
coal
is
thus
unjustified
and
lacking
in
any
reasoned
basis.
Moreover,
the
approach
unfairly
subjects
those
who
live
near
power
plants
burning
lower
rank
coal
to
much
higher
levels
of
Hg
emissions.
EPA
must
take
into
account
recent
information
that
shows
technology
is
currently
available
to
achieve
high
levels
of
Hg
control
on
a
cost­
effective
basis
regardless
of
the
rank
of
coal
to
be
burned
and
use
this
information
to
set
uniform,
protective
standards.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
determining
unit­
level
allocation
under
EPA's
example
allocation
methodology
for
States.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.
EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter's
(
OAR­
2002­
0056­
5492)
question:
"
EPA
is
seeking
additional
detailed
data
addressing
the
validity
of
the
costs
assumed
for
ACI."

The
response
to
this
question
is
divided
into
two
parts:
activated
carbon
availability
and
development
of
new
sorbents.

Activated
carbon
availability:
If
the
activated
carbon
industry
converted
to
a
24/
7
production
scenario,
then
the
productivity
would
conservatively
lead
to
about
60,000
tpy
of
excess
carbon
available
in
the
U.
S.
Assuming
a
15
lb/
MMcfm
activated
carbon
injection
rate
used
in
conjunction
with
CS­
ESP,
the
excess
activated
carbon
production
capacity
could
be
used
to
control
Hg
emissions
from
about
6
GWe
generating
capacity.
If
one
assumed
that
all
units
that
were
retrofitted
with
ACI
also
installed
fabric
filters,
then
the
assumed
injection
rate
would
be
lowered
to
about
1
lb/
MMcfm
and
about
105
GWe
of
capacity
could
be
controlled
using
9­
96
activated
carbon.
Since
EPA
modeling
suggests
that
about
2
GWe
of
ACI
capacity
will
be
required
in
2015,
the
cost
for
commercially
available
activated
carbon
between
now
and
2010
should
not
be
driven
upward
due
to
demand
vs.
supply
constraints.

Other
models
project
higher
ACI
installed
capacity.
In
the
Notice,
EPA
cited
model
results
that
projected
13
to
17
GWe
of
installed
ACI
capacity
for
cap
and
trade
scenarios
for
2010
annual
Hg
emissions
between
25­
34
tpy.
For
various
MACT
approaches,
the
installed
ACI
capacity
was
between
15
and
120
GWe.
The
worldwide
excess
production
capacity
is
estimated
to
be
150,000
tpy
of
activated
carbon.
Depending
on
the
injection
rate,
this
would
limit
the
installed
ACI
capacity
to
15­
22
GWe.
Regulations
which
require
more
than
22
GWe
of
ACI
capacity
would
cause
a
supply­
demand
constraint
and
cause
the
price
of
activated
carbon
to
increase
in
response
to
the
demand.
The
activated
carbon
supply
vs.
the
2010
installed
ACI
capacity
must
be
carefully
studied.

Development
of
new
sorbents;
The
activated
carbon
sorbent
is
the
largest
Hg
control
annual
cost
component.
There
have
been
numerous
tests
of
brominated
activated
carbons
on
Powder
River
Basin
and
lignite
coals.
In
those
tests,
significantly
improved
performance
has
been
recorded.
During
a
four
week
test
program
at
the
subbituminous
coal
fired,
360
MWe
Sunflower
Electric
Holcomb
Station,
Hg
removal
increased
from
a
baseline
of
less
than
20
percent
to
over
90
percent
for
the
entire
period
at
injection
rates
less
than
1
lb/
MMcfm.
The
projected
cost
of
the
sorbent
is
a
factor
of
two
higher
than
conventional
activated
carbons,
but
the
usage
rate
is
a
factor
of
seven
to
ten
less.
This
will
result
in
a
significant
decrease
in
annual
operating
cost.

There
is
potential
for
activated
carbon
injection
technology
to
reduce
costs
significantly,
by
a
factor
of
3
to
7
between
now
and
2010.
Utilities
can
take
advantage
of
improved
carbon
performance
since
they
can
change
their
carbon
specifications
after
the
equipment
is
installed.

Response:

Given
that
the
first
phase
cap
is
set
at
the
Hg
co­
benefits
of
CAIR,
EPA
does
not
project
significant
amount
of
ACI
to
be
retrofitted
until
the
2018
timeframe.
With
regard
to
demand
for
activated
carbon,
EPA
notes
that
markets
respond
to
the
demand
for
materials,
much
like
under
the
NOx
SIP
call
supply
for
catalyst
increased
with
demand.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
October
2002,
in
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
stated
that
while
the
technology
vendors
participate
in
conferences
and
announce
the
viability
of
control
technologies
(
mostly
Activated
Carbon
Injection)
for
~
200
MW
units,
there
have
been
known
and
guaranteed
controls
at
<
200
MW
units.
Worse,
virtually
no
vendors
have
focused
on
<
100
MW
units.
This
commenter
fully
supported
the
comments
submitted
by
UARG
and
the
study
conducted
by
Charles
Rivers
Associates
(
CRA)
on
the
inadequacy
of
a
three­
year
period
for
complying
with
EPA's
MACT
limits.
EPA
has
the
discretionary
authority
to
extend
the
compliance
deadline
by
a
year.
This
commenter
believes
that
EPA
should
use
its
discretionary
authority
under
§
112(
i)(
3)(
B)
and
extend
the
deadline
by
a
year
for
all
units,
and
it
should
assist
public
power
utility
units
needing
9­
97
even
more
time
in
obtaining
presidential
extensions
on
a
case­
by­
case
basis.

The
process
of
funding
and
installing
a
major
retrofit
is
different
for
small
public
power
systems
than
for
larger
investor­
owned
systems.
Public
power
units
must
normally
obtain
financing
through
publicly
approved
bonds.
This
is
not
a
process
that
moves
quickly,
nor
is
it
one
with
a
guarantee
of
success.
Once
the
funding
approval
process
is
completed,
these
small
units
most
then
compete
with
large,
privately
held
units
to
obtain
services
from
vendors
of
emission
control
equipment
and
to
procure
skilled
labor
to
install
that
equipment.
An
equipment
vendor
is
far
more
likely
to
be
responsive
to
a
large
utility
(
often
an
investor
utility)
seeking
a
number
of
multi­
million
dollar
retrofits
than
to
a
small
public
system
with
an
environmental
compliance
staff
of
one
or
two
Full­
time
Equivalents
(
FTEs)
and
a
limited
compliance
budget.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
Given
that
EPA
is
finalizing
a
cap­
and­
trade
approach,
the
program
would
not
necessarily
require
the
installation
of
coantrols
on
units
less
than
100
MW.

Comment:

The
commenter
(
OAR­
2002­
0056­
5404)
stated
that
currently,
most
power
plants
market
some
of
their
fly
ash
for
use
in
ready­
mix
concrete
and
other
beneficial
applications.
The
commenter
added
that
some
plants
with
scrubbers
market
gypsum
produced
in
the
wet
flue
gas
desulfurization
(
FGD)
process
for
use
in
wallboard
fabrication.

The
commenter
noted
that
as
explained
in
their
June
24
comments
and
the
comments
of
others,
installation
of
an
activated
carbon
injection
system
to
control
Hg
emissions
would
cause
elevated
carbon
levels
to
prevent
these
beneficial
uses
of
power
plant
fly
ash.
The
commenter
stated
that
activated
carbon
that
has
the
greatest
capture
efficiency
is
in
the
4­
8
micron
range.
The
commenter
added
that
most
of
this
activated
carbon
will
be
captured
by
the
plant's
ESP
or
fabric
filter,
and
thus
will
be
present
in
the
fly
ash.
The
commenter
further
added
that
testing
experience
has
shown
that,
because
of
the
small
size
of
these
carbon
particles,
some
of
the
activated
carbon
is
carried
through
into
the
scrubber
system.
The
commenter
stated
that
the
presence
of
carbon
in
either
fly
ash
or
the
gypsum
produced
by
wet
scrubbers
is
highly
problematic
to
beneficial
reuse.

The
commenter
stated
that
fly
ash
can
be
utilized
as
a
substitute
for
cement
in
ready­
mix
concrete
 
but
to
do
so,
it
needs
to
comply
with
ASTM­
C618,
which
specifies
the
maximum
acceptable
carbon
content
for
concrete
filler
applications.
The
commenter
added
that
it
is
necessary
to
limit
carbon
content
in
concrete
because
carbon
reduces
the
strength
of
the
concrete
and
causes
premature
failure.
The
commenter
noted
that
this
result
occurs
because
carbon
inhibits
air
entrainment
in
the
concrete.
The
commenter
stated
that
air
increases
the
strength
of
concrete
and
reduces
the
permeability
of
the
concrete.
(
The
commenter
noted
that
fly
ash
reduces
the
amount
of
Portland
cement
that
needs
to
be
used
in
the
concrete.)
According
to
the
commenter,
state
transportation
departments
typically
tighten
the
maximum
allowable
carbon
content
as
compared
to
the
ASTM
standard.
The
commenter
notes
that
the
ASTM
standard
for
9­
98
carbon
content
of
concrete
filler,
as
well
as
two
state
DOT
specifications,
are
shown
in
Table
2
below.

The
commenter
notes
that
gypsum
produced
in
wet
flue
gas
desulfurization
(
scrubber)
processes
is
used
in
construction
materials
and
wallboard.
The
commenter
also
notes
that
a
portion
of
the
gypsum
is
also
used
to
produce
spackling
or
"
mud"
for
wallboard
installation.
The
commenter
further
notes
that
for
cosmetic
reasons,
gypsum
needs
to
be
high
purity
and
white
in
color.
The
commenter
added
that,
however,
even
very
small
levels
of
carbon
in
wallboard
will
cause
the
paper
to
peel,
making
the
wallboard
unusable.
The
commenter
stated
that,
accordingly,
to
be
usable,
the
gypsum
material
quality
needs
to
be
high
with
very
small
amounts
of
carbon.
The
commenter
noted
that
gypsum
specifications
for
wallboard
use
also
are
set
forth
in
the
table
below.
The
commenter
pointed
out
that,
as
noted
above,
however,
because
of
the
small
size
of
the
ACI
carbon
particles,
some
carbon
will
inevitably
bleed
through
to
the
scrubber,
resulting
in
gypsum
product
degradation
(
and,
as
discussed
in
the
commenter's
June
24
comments,
potential
catastrophic
scrubber
foaming
issues).

Table
2.
Carbon
Content
Specifications
for
Product
Streams
Concrete/
Constructi
on
Pennsylvania
Department
of
Transportation
Texas
Department
of
Transportation
Wallboard
Ash
ASTM­
C618
<
6
percent
ASTM­
C618
and
<
4
percent
ASTM­
C618
and
<
3
percent
NA
Gypsum
*
NA
NA
*

*
gypsum
specification
is

92
percent
CaSO4
and

2
percent
total
inerts.
Inerts
include
a
combination
of
ash,
limestone
minerals
and
carbon.

The
commenter
stated
that
recently,
some
representatives
of
the
control
technology
industry
have
claimed
that
the
problem
of
increased
carbon
levels
in
fly
ash
and
scrubber
gypsum
has
been
"
solved."
The
commenter
stated
that,
for
example,
one
company
has
been
aggressively
marketing
a
brominated
activated
carbon
technology.
According
to
the
commenter,
they
claim
that,
because
the
bromination
results
in
less
carbon
being
needed
to
achieve
Hg
removal,
there
is
no
issue
of
increased
carbon
levels
in
fly
ash
with
this
technology.
The
commenter
stated
that
these
assertions
are,
to
date,
unproven.

The
commenter
stated
that
this
company
has
not
claimed
that
anything
in
its
process
eliminates
increased
carbon
levels
in
fly
ash;
it
simply
reduces
the
total
amount
of
carbon
used
in
the
injection
process.
The
commenter
further
stated
that,
however,
carbon
levels
may
still
exceed
ASTM
or
State
standards
(
or
the
specifications
of
the
companies
that
are
accepting
the
fly
ash)
 
and
may
still
be
high
enough
to
lower
the
structural
stability
of
the
concrete.
The
commenter
stated
that
this
is
particularly
the
case
because
the
DTE
St.
Clair
plant
on
which
the
company's
ACI
was
tested
included
an
inordinately
large
ESP,
one
of
the
largest
in
the
industry.
The
commenter
stated
that,
indeed,
this
ESP
was
700
SCA,
as
compared
to
much
smaller
ESP
with
an
average
size
of
200­
250
SCA
for
the
rest
of
the
industry.
According
to
the
commenter,
as
a
result,
the
St.
Clair
plant
was
able
to
achieve
a
higher
removal
efficiency
with
a
lower
level
of
carbon
injections
than
would
be
expected
from
most
power
plants,
raising
further
concerns
about
9­
99
the
actual
levels
of
carbon
that
would
be
present
in
the
fly
ash.
The
commenter
stated
that,
in
addition,
the
tests
at
St.
Clair
were
of
very
short
duration
and
are
not
of
sufficient
length
to
be
considered
"
commercial
operation."

The
commenter
stated
that
even
if
the
ash
meets
ASTM
specifications,
does
not
impact
the
structural
stability
of
concrete
and
would
otherwise
be
acceptable
to
concrete
manufacturers,
the
levels
of
carbon
present
in
the
ash
would
discolor
the
concrete
 
and
thus
almost
certainly
render
it
unacceptable
to
most
concrete
manufacturers.
The
commenter
added
that,
similarly,
as
noted
above,
even
trace
amounts
of
carbon
(
which
certainly
would
be
expected
even
from
the
smaller
amounts
of
brominated
ACI
proposed
by
the
company)
would
render
scrubber
waste
unusable
as
gypsum.
The
commenter
stated
that,
thus,
even
if
the
carbon
issue
could
be
solved
with
respect
to
fly
ash,
it
would
not
be
solved
with
respect
to
scrubber
gypsum.

The
commenter
stated
that,
in
sum,
the
control
technology
industry
has
not
yet
come
close
to
proving
that
the
issue
of
increased
carbon
levels
in
fly
ash
is
solved.
The
commenter
added
that
yet
a
single
power
plant
can
generate
thousands
of
tons
of
fly
ash
and
gypsum
per
day,
and
if
those
wastes
cannot
be
beneficially
reused,
they
must
be
disposed
of.
The
commenter
further
added
that
the
cost
and
adverse
environmental
effects
associated
with
that
disposal
would
be
further
exacerbated
by
the
fact
that
building
materials
and
wallboard
manufacturers
would
be
forced
to
purchase
natural
gypsum
instead
of
reusing
the
plant's
byproducts.
The
commenter
stated
that,
also,
the
more
plants
that
are
required
to
install
activated
carbon
injection,
the
less
gypsum
would
be
available
for
use
in
wallboard
manufacture
 
and
the
more
mining
that
would
be
required.
The
commenter
further
stated
that
this
major
increase
in
mining
activity
would
have
additional
significant
adverse
environmental
impacts.
The
commenter
stated
that,
finally,
vast
amounts
of
activated
carbon
will
need
to
be
produced
and
transported
to
support
wide­
spread
application
of
ACI
technology
for
the
control
of
Hg
emissions.
Accordingly,
notwithstanding
recent
developments
in
ACI
technology,
the
commenter
believed
that
it
would
be
inappropriate
for
EPA
to
base
its
Hg
removal
program
on
broad
use
of
ACI
without
first
considering
the
serious
environmental
impacts
associated
with
disposal
of
millions
of
tons
of
new
solid
waste
per
year,
as
well
as
the
environmental
impacts
associated
with
production
and
transport
of
activated
carbon,
and
the
mining
of
gypsum
to
replace
that
which
currently
comes
from
scrubber
gypsum.
The
commenter
stated
that
indeed,
§
112(
d)(
2)
and
§
111
(
d)
both
specifically
require
EPA
to
consider
such
"
non­
air
quality
health
and
environmental
impacts"
when
setting
standards,
thus
mandating
that
EPA
consider
such
effects
before
it
can
set
standards
that
would
require
ACI.

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
EPA
also
notes
that
ACI
with
a
pulse­
jet
fabric
may
be
installed
upstream
of
wet
scrubber.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
Given
that
the
first
phase
cap
is
set
at
the
Hg
co­
benefits
of
CAIR,
EPA
does
not
project
significant
amount
of
ACI
to
be
retrofitted
until
the
2018
timeframe.
With
regard
to
demand
for
activated
carbon,
EPA
notes
that
markets
respond
to
the
demand
for
materials,
much
like
under
the
NOx
SIP
call
supply
for
catalyst
increased
with
demand.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
9­
100
October
2002,
in
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
the
cost
of
activated
carbon
could
significantly
increase
if
the
demand
exceeds
the
supply.
Depending
on
the
final
carbon
specifications,
the
annual
excess
activated
carbon
capacity
is
60,000
tpy
(
US),
30,000
tpy
(
Germany),
and
60,000
tpy
(
China)
for
a
total
worldwide
excess
capacity
if
150,000
tpy.
EPA's
IPM
modeling
projects
that
13
GWe
of
ACI
could
be
installed
by
2010.
At
a
15
lb/
MMacf
injection
rate,
13
GWe
of
capacity
is
equivalent
to
a
consumption
of
130,000
tpy
of
activated
carbon.
This
is
about
87
percent
of
the
worldwide
excess
capacity.
At
a
10
lb/
MMacf
injection
rate,
13
GWe
of
installed
ACI
would
consume
about
87,000
tpy
of
activated
carbon
or
58
percent
of
worldwide
excess
capacity.
This
analysis
assumes
that
ACI
is
installed
only
on
units
equipped
with
CS­
ESPs
(
a
conservative
assumption).
If
a
significant
fraction
of
units
were
equipped
with
FF,
then
the
carbon
injection
rate
would
be
lowered
to
4
to
5
lb/
MMacf.
If
all
units
retrofitted
with
ACI
were
equipped
with
FF,
then
the
projected
annual
carbon
usage
would
be
43,500
tpy,
which
is
72
percent
of
the
excess
US
capacity.

If
ACI
installations
were
to
exceed
about
15­
20
GWe,
then
the
demand
for
activated
carbon
would
exceed
the
supply
and
the
delivered
cost
could
increase
dramatically.
Greater
demand
could
be
offset
by
the
construction
of
additional
activated
carbon
production
capacity.
For
example,
RWE
is
one
of
the
world's
leading
producers
of
activated
carbon.
Their
product,
"
HOK,"
has
been
tested
successfully
for
Hg
reduction
at
power
plants
in
the
U.
S.,
and
is
used
for
similar
purposes
in
Europe.
According
to
Juergen
Wirling,
RWE's
international
sales
manager,
"
if
appropriate
supply
and
purchase
agreements
are
concluded
and
economic
efficiency
is
given,
an
[
additional]
annual
delivery
quantity
of
over
100,000
tonnes
of
Activated
Lignite
will
be
possible.
A
prerequisite
here
is
that
for
sales
planning
purposes
or
the
initiation
of
measures
aimed
at
stepping
up
production,
a
minimum
lead
time
of
three
to
four
years
will
be
available.
The
[
RWE]
annual
production
capacity
of
Activated
Lignite
already
amounts
to
approx.
200,000
tonnes
today.
The
raw
material
lignite
is
extracted
from
the
Group's
own
surface
mines,
so
that,
in
this
respect
too,
sufficient
security
is
provided."

These
data
indicate
that,
while
the
supply
of
activated
carbon
is
marginally
sufficient
to
meet
projected
near­
term
needs
of
about
10
GW
capacity,
there
is
reason
for
concern
if
ACI
installations
exceed
expectations,
and
for
the
adequacy
of
longer
term
supply,
if
levels
of
ACI
usage
reach
those
projected
by
various
modelers.
EPA
should
consider
explicitly
the
elasticity
of
ACI
supply
and
demand
in
modeling
the
cost
of
ACI
applications.

A
second
issue
is
the
development
of
promoted
(
e.
g.,
brominated)
activated
carbons.
According
to
NORIT,
brominated
carbon
would
cost
about
30
percent
more
than
the
current
NORIT
FGD
costs
of
about
$
0.50/
lb
delivered,
or
$
0.65/
lb
to
$
0.70/
lb
delivered.
However,
if,
as
projected
based
on
recent
research,
the
brominated
carbon
dosage
is
one­
seventh
the
standard
carbon
dosage
for
equivalent
Hg
removal,
the
cost
of
ACI
would
be
significantly
lower
using
brominated
activated
carbon.
Assuming
a
10
lb/
MMacf
dosage
for
NORIT
FGD
and
$
0.50
lib
carbon
cost
and
a
1.42
lb/
MMacf
dosage
for
the
brominated
carbon
and
a
$
0.70
cost,
the
use
of
brominated
carbon
would
lower
the
sorbent
cost
by
a
factor
of
five.
9­
101
There
have
been
a
number
of
intermediate
term
(
two
week
to
one
month
tests)
tests
of
brominated
carbon.
The
Hg
removal
at
a
site
burning
PRB
coals
and
equipped
with
a
SDA/
FF
averaged
93
percent
at
an
injection
concentration
of
1.2
lb/
MMacf.
The
results
support
the
significant
reduction
in
carbon
dosage
rate.
At
the
recent
PowerGen
Conference,
Hg
reduction
vs.
injection
rate
performance
data
were
presented.
For
a
plant
burning
PRB
coal
and
equipped
with
a
CS­
ESP,
>
90
percent
Hg
reduction
was
achieved
at
a
brominated
carbon
injection
rate
of
about
1.5
lb/
MMacf.
This
is
significantly
better
performance
than
NORIT
FGD,
which
achieved
75
percent
reduction
at
an
injection
rate
of
about
6
lb/
MMacf.
For
a
500
MWe
boiler
with
a
SDA/
FF
burning
a
PRB
coal,
the
NORIT
FGD
would
cost
$
4,000,000
per
year
and
the
NORIT
brominated
carbon
would
cost
$
1,000,000
per
year.
The
Hg
removal
cost
effectiveness
was
lowered
improved
from
$
8,000/
lb
to
$
2,000/
lb.
Questions
remain
about
the
environmental
impact
of
using
brominated
sorbents,
but
the
performance
and
cost
improvements
suggested
by
these
results
warrant
further
evaluation.
EPA
should
evaluate
the
cost
impacts
of
advanced
sorbents
using
the
IPM
model
because
significant
advances
in
sorbent
technology
are
occurring.

Response:

Given
that
the
first
phase
cap
is
set
at
the
Hg
co­
benefits
of
CAIR,
EPA
does
not
project
significant
amount
of
ACI
to
be
retrofitted
until
the
2018
timeframe.
With
regard
to
demand
for
activated
carbon,
EPA
notes
that
markets
respond
to
the
demand
for
materials,
much
like
under
the
NOx
SIP
call
supply
for
catalyst
increased
with
demand.
See
Engineering
and
Economic
Factors
Affecting
the
Installation
of
Control
Technologies
for
Multipollutant
Strategies,
EPA,
October
2002,
in
docket.
EPA
has
included
the
examination
of
technology
improvement
in
its
analysis
of
the
costs
of
the
final
rulemaking.
EPA
has
performed
a
sensitivity
analysis
assuming
the
introduction
of
a
second
ACI
using
advanced
sorbents,
leading
to
lower
capital
costs.
See
sensitivity
analysis
in
Chapter
7
of
final
CAMR
Regulatory
Impact
Analysis.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
it
was
inappropriate
for
an
economic
forecast
to
assume
a
decrease
in
fixed
capital
costs
of
Hg
control
technologies.
The
utility
industry
learned
from
its
experience
with
SCRs
that
EPA's
and
state
regulators'
early
estimates
were
far
lower
than
actual
capital
costs.
This
is
relevant
because,
like
SCR,
plant­
specific
ACI
costs
and
balance
of
plant
issues
remain
uncertain
and
actual
costs
will
be
driven
by
those
factors.
In
addition,
costs
will
have
to
be
adjusted
higher
to
reflect
the
changes
in
the
price
and
availability
of
steel.
In
the
late­
1990s,
Northeast
States
for
Coordinated
Air
Use
Management
(
NESCAUM)
stated
that
most
SCR
applications
would
cost
$
80­
90/
kW.
EPA's
Acid
Rain
Division
estimated
capital
costs
between
$
40
75/
kW
and
the
Institute
of
Clean
Air
Companies
(
ICAC)
predicted
capital
costs
around
$
50/
kW.
In
2004,
EPA
is
still
publishing
cost
algorithms
that
generally
argue
the
capital
cost
is
less
than
$
100/
kW.
Two
recent
surveys
to
determine
installed
SCR
equipment
cost
show
actual
incurred
costs
average
$
125­
140/
kW,
and
for
some
installations
approach
$
200/
kW.

From
time­
to­
time,
EPA
and
environmental
groups
assert
that
the
costs
of
SO
2
control
in
9­
102
the
Acid
Rain
program
"
proves"
that
costs
of
pollution
control
equipment
are
always
much
lower
than
originally
estimated.
This
argument
is
a
red
herring.
The
costs
of
the
SO2
program
declined
because
of
extrinsic
economic
factors
that
are
unlikely
to
be
repeated
in
any
other
situation.
The
federal
government
deregulated
the
railroad
industry
in
the
early
1990s,
thereby
vastly
reducing
the
costs
of
transporting
western
low
sulfur
coal
to
the
east.
Many
utilities
were
able
to
switch
fuel
supplies
and
avoid
control
technology
costs
altogether.
This
hardly
shows
that
SO
2
control
technologies
dropped
considerably.
A
more
apt
comparison
(
but
unlikely
scenario)
in
this
context
would
be
an
assumption
that
natural
gas
prices
dropped
so
low
that
coal
fired
power
plants
were
able
to
"
lower"
Hg
control
costs
by
switching
from
coal
to
natural
gas.

A
complete
assessment
of
Hg
control
technology
cost
requires
including
the
impact
of
elevated
carbon
in
ash
on
solid
byproduct
management.
Higher
carbon
in
fly
ash
will
compromise
its
market
value,
perhaps
eliminating
the
resale
option
entirely,
and
requiring
disposal
and
management.
The
utility
industry
has
known
for
decades
that
when
combustion
NOx
controls
are
utilized
that
higher
carbon
in
ash
can
render
fly
ash
unmarketable.
This
is
especially
true
for
concrete,
which
is
the
largest
and
most
valuable
byproduct
use
of
fly
ash.
According
to
the
American
Coal
Ash
Association
(
ACAA),
fly
ash
for
sale
as
concrete
supplement
derives
the
highest
resale
value
($
20­$
45/
ton),
and
comprises
by
far
the
largest
end
use
category.
Virtually
all
Portland
cement
is
prepared
with
several
additives
to
enhance
the
following
features:
it
must
be
"
workable"
or
easy
to
pore
into
forms
and
shape;
undamaged
by
exposure
to
alternating
freeze
and
thaw
environments;
and
consume
a
minimum
amount
much
water
to
maximize
ultimate
strength.
The
problem
with
carbon
in
fly
ash
is
that
it
interferes
with
all
of
these
features
in
concrete.

In
general,
carbon
content
of
fly
ash
must
be
5
percent
or
less
to
be
marketable,
which
is
generally
achievable
for
most
units
that
fire
their
design
coal
and
have
properly
tuned
combustion
systems.
However,
injecting
ACI
will
generally
elevate
carbon
in
fly
ash
by
approximately
4
percent
above
the
3­
4
percent
that
would
otherwise
be
expected.
This
tends
to
render
concrete
made
from
such
ash
discolored,
weakened,
more
difficult
to
work,
and
less
durable
in
freezing
climates.
These
problems
would
likely
worsen
with
halogenated
ACI.

The
impact
of
elevated
carbon
in
fly
ash
on
the
cost
of
using
ACI
for
Hg
control
is
due
to
both
loss
of
revenue
from
the
sale
of
fly
ash
and
the
costs
of
permitting
and
disposing
of
material
that
previously
was
sold.
The
commenter's
comments
previously
assumed
that
35
percent
of
the
fly
ash
generated
in
the
U.
S.
would
be
rendered
unmarketable
and
incur
a
charge
of
$
24/
ton
due
to
a
revenue
loss
of
$
12/
ton
and
a
disposal
and
management
fee
of
$
12/
ton.
The
commenter
has
now
updated
their
prior
estimates.
The
weighted
value
of
the
revenue
from
ash
sales,
using
information
from
the
ACAA,
is
about
$
24/
ton.
The
costs
of
disposal
can
vary
widely
on
a
case­
by­
case
basis,
but
information
provided
by
the
ACAA
supports
an
average
cost
of
$
12/
ton.
Thus
the
cost
to
utilities
that
can
do
longer
dispose
of
their
fly
ash
because
they
are
using
ACI
is
probably
closer
to
$
36/
ton.

Response:

See
comment
response
above
for
discussion
of
EPA
modeling
assumption
for
control
technology
costs.
EPA
also
notes
that
ACI
with
a
pulse­
jet
fabric
may
be
installed
upstream
of
wet
scrubber.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
9­
103
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

6.
Analyses
of
Hg
trading
programs
by
EPA
and
commenters
indicate
that
variations
in
the
first
phase
cap
level
and
timing
of
the
cap
impact
when
the
final
cap
level
will
be
achieved.
Although
banking
in
the
first
phase
impacts
the
timing
of
achieving
the
second
phase
cap,
it
should
not
affect
the
cumulative
Hg
emissions
reduction
ultimately
achieved.
EPA
is
seeking
additional
information
on
the
impact
banking
may
have
on
the
timing
of
achieving
the
second
phase
cap.

Comment:

One
commenter
(
OAR­
2002­
0056­
5561)
stated
that
in
addition,
the
commenter
had
the
following
specific
comment
on
the
environmental
impacts
of
emissions
banking,
which
is
informed
by
the
modeling
that
occurred
within
the
commenter's
Air
Quality
Dialogue.
Modeling
conducted
in
the
commenter's
Air
Quality
Dialogue
indicated
that
emissions
banking
could
be
beneficial
from
an
environmental
standpoint,
potentially
resulting
in
important
near­
term
emissions
reductions
and
environmental
improvements
that
could
outweigh
the
additional
time
required
to
meet
a
second
phase
cap.
In
a
scenario
without
a
Phase
1
emissions
cap
(
the
Phase
2
cap
was
set
at
10
tons
in
2018),
the
modeling
projects
that
firms
would
delay
any
action
until
the
approach
of
the
binding
cap,
resulting
in
16
percent
fewer
reductions
in
Hg
emissions
on
a
cumulative
basis
through
2022
than
under
a
comparable
scenario
that
included
a
Phase
1
cap
set
at
26
tons.
The
cost
savings
from
not
having
to
meet
a
26­
ton
Phase
1
cap
were
insignificant
(
net
present
value
of
$
0.3
billion
for
the
2005
to
2030
period)
in
the
scenario
without
a
Phase
1
cap,
and
the
modeling
showed
a
spike
in
costs
just
before
the
compliance
year.
Of
course,
the
relative
environmental
and
cost
advantages
of
banking
would
depend
on
the
chosen
cap
levels
and
timing.
The
commenter
expected
the
near­
term
environmental
benefits
of
emissions
banking
would
be
reduced
if
the
first
phase
cap
is
set
at
a
co­
benefits
control
level.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
said
that
in
regard
to
banking
and
the
timing
of
achieving
the
second
phase
cap,
the
commenter
had
proposed
an
alternative
cap
and
trade
program,
which,
among
other
things,
significantly
reduces
the
amount
of
banking
that
can
occur
prior
to
2018
 
increasing
the
likelihood
that
actual
coal­
based
power
plant
emissions
in
2018
will
be
15
tons.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
9­
104
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.

Comment:

One
commenter
(
OAR­
2002­
0056­
5493)
stated
that
pursuant
to
these
regulatory
proposals,
EPA
intends
to
reduce
Hg
emissions
from
coal­
fired
power
plants
by
70
percent
by
setting
a
permanent
15­
ton
cap
in
2018
regardless
of
the
future
growth
in
the
energy
sector.
Thus,
the
cap
would
effectively
become
more
stringent
as
more
power
plants
are
constructed
in
order
to
keep
their
collective
emissions
below
15
tons.
EPA
proposes
to
set
the
near­
term
Hg
emissions
cap
in
2010
at
a
level
that
can
be
achieved
through
the
installation
of
FGD
and
SCR
units
that
will
be
necessary
to
meet
2010
caps
on
SO
2
and
NO
x
under
existing
cap­
and
trade
programs.
The
commenter
agreed
with
EPA
that
this
"
multi­
pollutant"
approach
is
the
most
effective
and
reasonable
way
to
reduce
emissions
from
coal­
fired
power
plants
in
the
near­
term.

However,
there
is
no
provision
in
the
proposed
cap­
and­
trade
approach
that
permits
credit
for
reduction
of
Hg
emissions
achieved
before
the
near­
term
cap
become
effective
in
2010.
The
Building
and
Construction
Trades
Department
(
BCTD)
of
the
AFL­
CIO
agrees
with
the
comments
submitted
by
the
Unions
for
Jobs
and
the
Environment
on
June
29,
2004,
that
a
mechanism
should
be
incorporated
in
the
proposed
rule
that
affords
credit
for
reduction
of
Hg
emissions
in
advance
of
the
2010
cap
date.
Such
credit
would
encourage
the
installation
and/
or
modification
of
technologies
sooner
than
later
thereby
helping
to
avoid
the
inevitable
last­
minute
crunch
that
will
create
an
unnecessary
burden
on
the
limited
supply
of
skilled
manpower
available
to
install
FGD
and
SCR
units.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.
EPA
is
not
including
a
provision
for
early
reduction
credits
in
the
final
rulemaking.
See
Chapter
5
response
to
comments
for
further
discussion
of
ERCs.

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
stated
that
emissions
were
projected
to
be
15
tons
by
2020
in
every
Cap
and
Trade
case
examined
using
the
EPMM
and
reported
to
EPA
in
June
2004.
In
the
NODA,
EPA
characterized
the
2020
emissions
estimates
reported
for
EPMM
Cap
and
Trade
scenarios
as,
variously,
either
23
or
24
tons.
Additional
examples
are
provided
demonstrating
the
validity
and
robustness
of
the
earlier
projection
of
about
15
tons
by
2020.

Response:

EPA
has
examined
the
commenters
analysis
and
notes
that
its
own
analysis
shows
a
more
gradual
emission
glide
path
in
meeting
the
second
phase
cap.
See
Chapter
7
of
final
rule
RIA
9­
105
for
further
discussion
of
EPA
emissions
projections.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
stated
that
EPA
seeks
comment
on
a
number
of
economic
modeling
analyses
performed
by
different
stakeholder
groups.
The
commenter's
primary
comment
on
this
aspect
of
the
NODA
was
that
it
fails
to
honor
the
commitment
Administrator
Leavitt
made
to
the
public:
to
ensure
that
the
rule
will
be
"
done
in
a
way
that
will
maximize
the
level
of
reductions"
based
on
the
available
technology.
In
particular,
the
NODA
does
not
present
any
new
EPA
analyses
of
stricter
MACT
scenarios,
much
less
examine
the
different
control
options
put
forward
by
stakeholder
groups
participating
in
the
Utility
MACT
Working
Group.

A
second
concern
the
commenter
had
regarding
the
various
cap­
and­
trade
scenarios
that
were
modeled
was
that
none
ensures
that
actual
emissions
will
be
equal
to,
or
lower
than,
the
cap
level
by
the
date
the
cap
goes
into
effect.
For
example,
the
Center
for
Clean
Air
Policy
(
CCAP)
modeled
a
7.5
ton
cap
in
2015,
yet
the
results
predict
that
11
tons
will
still
be
emitted
in
2020.
EPA
asks
for
comments
on
the
so­
called
"
glide
path"
of
the
reductions,
and
the
commenter
reiterated
their
earlier
comments
that
the
safety
valve
provision
and
the
facilities'
unrestricted
ability
to
borrow
from
future
allowance
years
means
that
emissions
will
continue
to
exceed
the
cap
far
into
the
future,
perhaps
indefinitely.
EPA
must
recognize
that
the
cap
and
trade
options
all
result
in
a
cumulative
loading
of
Hg
into
the
environment
for
10
to
20
years
longer
than
a
proper
MACT
standard,
in
far
greater
amounts.
This
additional
loading
of
a
persistent,
bioaccumulative
metal
is
unacceptable.

With
regard
to
the
specific
modeling
results,
the
analysis
that
was
of
most
interest
to
the
commenter
was
the
Cinergy
Corporation's
(
Cinergy)
"
stringent
MACT"
modeling,
and
the
commenter's
assessment
of
that
approach
is
discussed
in
detail
below.
Before
turning
to
Cinergy's
modeling,
however,
it
bears
reiterating
our
prior
comments
about
the
CCAP
work.
CCAP's
report
states:

Tightening
the
mercury
emissions­
reduction
cap
from
15
tons
in
2018
to
10
tons
in
2018
is
projected
to
increase
total
[
three
pollutant
program]
compliance
costs
by
approximately
5
percent
($
3.1
billion
in
net
present
value
terms).
Further
tightening
the
cap
by
advancing
the
compliance
date
to
2015
would
add
approximately
another
5
percent
to
total
3P
costs,
and
reducing
the
cap
to
7.5
tons
in
the
same
compliance
period
would
increase
total
3P
costs
by
an
additional
4
percent.
In
addition,
even
the
most
aggressive
of
these
options
(
7.5
tons
cap
in
2015)
has
almost
no
impact
on
wholesale
electricity
prices
both
nationally
(
within
0.2
percent)
and
regionally
(­
1.5
to
2.1
percent),
reflecting
how
the
cost
may
not
be
passed
on
directly
to
wholesale
electricity
consumers.
Cumulative
mercury
emission
reductions
increase
between
8
and
28
percent
through
2022
with
these
more
aggressive
caps
and
timetables.
Moreover,
the
impact
of
such
changes
on
national
and
regional
coal
production
is
slight
(­
1
to
5
percent).

What
that
means
for
present
purposes
is
that
even
if
EPA
persists
in
its
unlawful
scheme
to
regulate
Hg
pollution
under
section
111
of
the
Clean
Air
Act
(
which
of
course
it
should
not
do),
a
much
more
stringent
approach
is
economically
feasible.
9­
106
Cinergy
modeled
a
MACT
control
regime
becoming
effective
in
2008
and
reducing
approximately
39
tons
of
annual
Hg
emissions
(
an
81
percent
cut).
Even
though
Cinergy's
assumptions
included
higher
capital
costs
and
less
Hg
co­
control
by
NO
x
and
SO
2
controls
than
EPA's
modeling,
and
also
included
the
extreme
assumption
that
activated
carbon
injection
(
ACI)
would
not
be
available
until
after
2010,
the
commenter
note
that
the
average
annual
costs
of
control
in
2010
and
2020
(
calculated
by
dividing
the
net
present
value
of
$
130
billion
in
2010
and
2020
by
20
years)
are
on
the
order
of
$
6.5
billion,
which
is
economically
feasible.
Although
the
NODA
states
that
Cinergy's
modeling
of
this
scenario
resulted
in
significant
increases
in
power
prices
and
fuel
prices
in
the
short
term,
the
commenter
was
unable
to
verify
that
this
is
indeed
the
case
as
the
full
model
results
inexcusably
were
not
included
in
the
public
version
of
Cinergy's
comments.
The
public
deserves
the
right
to
see
the
concurrent
SO
2
reductions
of
Cinergy's
stringent
MACT
scenario
to
see
if
the
benefits
of
this
scenario
outweigh
the
costs.
The
commenter
had
every
reason
to
believe
they
do.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
Discussion
of
EPA's
cost
modeling
can
be
found
in
Chapter
7
of
the
final
CAMR
RIA.
Further
details
on
commenters
analysis
are
found
in
their
submittals
to
the
docket.

Comment:

The
commenter
(
OAR­
2002­
0056­
5455)
noted
that
in
studying
Table
1
of
the
NODA,
it
appeared
that
it
really
was
not
much
more
expensive
to
control
Hg
emissions
to
7.5
tons
per
year
rather
than
15
tons
per
year.
A
two­
phase
cap
of
15
tons
was
projected
to
cost
$
3.3
billion
by
2010
and
$
6.7
billion
by
2020.
But
a
two­
phase
cap
of
7.5
tons
was
expected
to
cost
$
4.6
billion
by
2010
and
$
7.1
billion
by
2020.
The
difference
by
2020
is
only
6
percent.
For
all
of
EPA's
sloppy
calculations,
incorrect
assumptions,
and
failure
to
carry
out
a
proper
MACT
determination,
it
only
made
a
6
percent
difference
in
cost.
It
would
be
hard
to
overstate
the
level
of
disgust
in
the
Indian
community
over
the
way
EPA
has
handled
this
rulemaking.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
Discussion
of
EPA's
cost
modeling
can
be
found
in
Chapter
7
of
the
final
CAMR
RIA.

Comment:

The
commenter
(
OAR­
2002­
0056­
5404)
stated
that
the
NODA
recognizes
that
"[
a]
lthough
banking
in
the
first
phase
impacts
the
timing
of
achieving
the
second
phase
cap,
it
should
not
affect
the
cumulative
Hg
emissions
reductions
ultimately
achieved
under
the
program."
69
Fed.
Reg.
69870.
The
commenter
stated
that
EPA
nonetheless
requests
comment
on
"
the
impact
banking
may
have
on
the
timing
of
achieving
the
second
phase
cap."
Id.
The
commenter
strongly
supported
unrestricted
banking
of
Hg
allowances;
according
to
the
commenter,
indeed,
9­
107
there
is
no
policy
basis
to
restrict
trading,
even
if
unrestricted
banking
delays
the
date
by
which
sources
achieve
source­
specific
limits
that
correspond
to
the
Phase
II
emissions
reductions
on
an
annual
basis.

The
commenter
stated
that
in
addition
to
having
no
impact
on
the
cumulative
Hg
emissions
reductions
ultimately
achieved
under
a
cap­
and­
trade
program,
if
unrestricted
banking
means
(
as
it
likely
will)
that
the
Phase
II
cap
will
not
be
achieved
exactly
by
2018,
this
will
be
the
case
because
Phase
I
Hg
reductions
will
have
gone
beyond
what
Phase
I
requires.
According
to
the
commenter,
that
is,
Hg
allowances
have
a
vintage
year
before
which
they
cannot
be
used;
thus
a
source
can
exceed
the
Phase
II
cap
in
2018
only
if
it
has
reduced
emissions
beyond
what
is
required
under
Phase
I,
carrying
Phase
I
allowances
over
to
Phase
II.
The
commenter
stated
that
these
greater
emissions
reductions
achieved
during
Phase
I
arguably
are
preferable
for
the
environment,
but
at
a
minimum
are
neutral
from
an
environmental
perspective.

The
commenter
stated
that
the
fact
that
emissions
in
Phase
II
may
exceed
the
cap
because
of
surplus
reductions
in
Phase
I
can
pose
no
adverse
environmental
consequences
unless
the
pollutant
at
issue
poses
significant
acute
health
risks.
According
to
the
commenter,
Hg
is
not
such
a
pollutant;
environmental
issues
associated
with
Hg
result
from
the
deposition
of
Hg
on
water
is
converted
to
methylmercury
(
MeHg),
which
in
turn
can
bioaccumulate
in
fish,
and
subsequently
in
people.
The
commenter
stated
that
this
is
a
long­
term
process,
however,
and
concerns
regarding
Hg
emissions
should
focus
on
cumulative
environmental
loadings
over
time,
not
on
local,
short­
term
emissions.
According
to
the
commenter,
unrestricted
banking
cannot,
by
definition,
allow
cumulative
emissions
over
the
life
of
the
program
to
exceed
what
they
would
be
if
banking
were
restricted.
The
commenter
stated
that,
thus,
no
policy
basis
exists
for
any
restriction
on
the
banking
of
Hg
emissions.

The
commenter
added
that,
moreover,
there
are
significant
policy
benefits
to
allowing
unrestricted
banking.
The
commenter
stated
that
banking
can
provide
significant
cost
savings
with
respect,
as
well
as
promoting
efficient
emissions
reduction.
The
commenter
added
that
unrestricted
banking
will
also
provide
affected
sources
with
valuable
compliance
flexibilities
and
incentives
for
technological
development.
The
commenter
stated
that,
as
noted
in
their
June
24
comments,
no
currently
available
control
technology
exists
that
would
enable
the
power
generation
sector
to
achieve
a
15
ton
cap.
The
commenter
further
stated
that
by
permitting
unrestricted
banking,
system
owners
and
operators
will
have
the
incentive
to
reduce
Hg
emissions
earlier
and
in
amounts
greater
than
the
rule
requires
in
order
to
bank
allowances
that
they
can
use
to
facilitate
compliance
at
the
beginning
of
Phase
II.
The
commenter
stated
that
these
allowance
surpluses
will
give
sources
the
compliance
flexibility
they
need
to
experiment
with
promising
new
technologies
 
which
may
have
the
potential
to
reduce
Hg
emissions
efficiently
and
cost­
effectively
 
without
fear
of
consequences
associated
with
non­
compliance.
According
to
the
commenter,
unrestricted
banking
will
thereby
ease
the
regulatory
burdens
associated
with
achieving
the
2018
cap
because
sources
will
have
greater
flexibility
to
identify
and
implement
new,
promising
control
technologies.
The
commenter
stated
that,
moreover,
as
noted
above,
unrestricted
banking
results
in
no
environmental
disbenefits.
The
commenter
further
stated
that
to
the
extent
that
Hg
emissions
from
power
plants
could
be
identified
as
a
human
health
concern,
such
concern
would
be
limited
to
the
contribution
of
those
emissions
to
the
global
pool.
The
commenter
stated
that
in
any
event,
a
flexible
cap
and
trade
program
with
unrestricted
banking
would
be
an
effective
mechanism
to
reduce
the
contribution
of
the
power
generation
sector
to
the
9­
108
global
Hg
pool.

The
commenter
noted
that,
in
sum,
permitting
sources
to
retain
unused
allowances
from
one
calendar
year
for
use
in
a
later
calendar
year
will
encourage
early
emissions
reductions,
provide
flexibility
to
affected
sources
to
meet
environmental
objectives,
and
facilitate
the
development
of
new,
innovative
Hg
reduction
control
strategies.
The
commenter
stated
that
given
that
unrestricted
banking
provides
the
foregoing
benefits
with
no
corresponding
environmental
disbenefits,
EPA
should
allow
unrestricted
banking
in
the
final
rule.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
based
on
their
review
of
the
available
information,
the
commenter
could
find
no
plausible
basis
to
employ
any
allowance
allocation
adjustment
factors
by
coal
rank
for
any
cap
that
is
in
effect
after
2014.
The
level
of
the
cap
is
irrelevant;
because
by
2014
EPA
projects,
and
proposes
to
rely
upon,
the
commercial
availability
of
Hg­
specific
control
technologies,
and
these
technologies
are
expected
to
deliver
reasonably
similar
removals
across
all
coal
ranks.

Response:

The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
determining
unit­
level
allocation
under
EPA's
example
allocation
methodology
for
States.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
bituminous
users
and
subbituminous
users
that
do
not
comply
with
their
Hg
reduction
obligations
through
co­
benefits
will
have
to
purchase
allowances
under
the
trading
program,
and
that
price
will
not
vary
depending
on
the
rank
of
coal
burned
by
the
allowance
purchaser.
That
is
the
very
point
of
a
trading
program,
which
is,
as
EPA
notes,
"
cost­
effective,"
because
it
allows
sources
that
can
reduce
Hg
more
cost­
effectively
to
do
so,
and
pass
those
savings
on
to
other
units
that
cannot
make
reductions
that
are
as
cost­
effective.
In
other
words,
under
a
trading
program,
sources
with
the
lowest
compliance
costs
bear
the
burden
of
control.

There
are
those
who
might
be
concerned
about
allowance
availability
on
a
unit­
specific
9­
109
basis,
even
though
co­
benefits
reductions
will
generate
adequate
allowances
on
an
aggregate
basis.
While
this
potential
concern
is
one
that
is
equal
across
coal
ranks,
because
there
will
be
many
bituminous
units
that
will
be
relying
on
allowance
purchases
for
compliance
as
well
as
units
burning
low
rank
coals,
this
concern
is
also
easily
addressed
through
restrictions
on
banking.
If
EPA
makes
adjustments
to
its
banking
provisions
to
largely
prohibit
banking,
particularly
in
the
first
few
years
of
any
co­
benefits
program,
all
allowances
will
be
held
on
a
"
use
it
or
lose
it"
basis,
and
consequently
will
be
sold
to
those
that
need
them
for
compliance.
The
commenter
did
not
believe
that
allowance
hoarding
is
a
likely
outcome,
nor
one
that
would
become
an
extended
practice,
but
a
phase­
in
provision
for
banking
whereby
banking
is
restricted
in
the
early
years
would
certainly
address
that
issue.
As
an
alternative,
and
likely
a
better
solution,
EPA
could
develop
a
conditional
restriction
on
banking
whereby
allowance
banking
is
prohibited
unless
the
allowances
are
first
offered
for
sale
at
an
annual
EPA
auction,
and,
if
not
purchased
by
one
that
needs
them
for
same
year
compliance,
may
be
banked
without
restriction.
This
approach
would
only
restrict
banking
to
the
degree
necessary
to
ensure
that
all
sources
that
must
rely
on
allowance
purchases
to
comply
under
a
co­
benefits
approach
can
obtain
them.
EPA
can
also
help
address
allowance
availability
concerns,
and
provide
an
incentive
for
early
adoption
of
Hg­
specific
control
technology,
by
restricting
banking
to
those
reductions
that
result
from
the
application
of
Hg­
specific
control
technology,
i.
e.,
beyond
simple
co­
benefit
reductions.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.
The
final
rule
takes
into
account
the
different
levels
of
mercury
control
that
lignite,
bituminous,
and
subbituminous
coals
can
achieve
using
existing
NOx
and
SO
2
controls
and
uses
coal
adjustment
factors
for
determining
the
state
emission
budgets
and
determining
unit­
level
allocation
under
EPA's
example
allocation
methodology
for
States.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
noted
that
EEI
commissioned
Charles
River
Associates
(
CRA)
to
perform
a
number
of
sensitivity
runs
using
EPMM
to
identify
those
factors
that
affect
the
"
glide
path"
and
the
timing
in
achieving
the
second
phase
cap.
CRA's
analysis
is
being
submitted
as
part
of
EEI's
NODA
comments
(
see
OAR­
2002­
0056­
5469).
The
commenter
refers
EPA
to
EEI's
NODA
comments
for
the
detailed
presentation
of
CRA's
work.

Briefly,
CRA's
work
shows
that
the
two
factors
that
have
the
greatest
impact
on
the
"
glide
path"
and
the
timing
of
emission
reductions
to
achieve
the
second
phase
cap
emission
level
are:
(
1)
how
closely
the
first
phase
cap
is
set
to
the
true
level
of
co­
benefits
and
(
2)
the
duration
of
the
first
phase
cap.
If
the
first
phase
cap
is
set
below
the
level
of
true
co­
benefits,
then
more
banking
would
occur
during
the
first
phase
and
full
achievement
of
the
second
phase
cap
emission
level
would
occur
later.
The
longer
the
duration
of
the
first
phase
cap,
the
greater
the
amount
of
banking
and,
again,
deferred
achievement
of
the
second
phase
cap
emission
level.
9­
110
Other
factors
with
smaller
effects
on
the
"
glide
path"
are
the
assumptions
one
uses
about
the
growth
in
the
use
of
low
sulfur
coal
and
the
stringency
of
the
second
phase
cap.
Changes
in
assumptions
about
the
growth
of
the
use
of
low
sulfur
coal
primarily
affect
the
level
of
predicted
co­
benefits
in
the
first
phase.
The
stringency
of
the
second
phase
cap
affects
the
ultimate
cost
of
compliance
and
hence
the
desire
of
companies
to
put
off
the
capital
costs
of
second
phase
compliance
by
early
banking.
CRA
found
that
changes
in
technology
cost
assumptions
do
not
have
a
major
impact
on
the
"
glide
path."

These
sensitivity
results
continue
to
point
out
the
wisdom
of
the
alternate
Hg
cap
and­
trade
proposal
offered
by
the
commenter
and
a
variety
of
other
industry
commenters.
That
proposal
would
not
set
a
"
hard"
cap"
for
the
first
phase;
rather,
the
Hg
co­
benefits
would
be
what
they
are.
Mercury
trading
would
not
be
allowed
during
the
first
phase,
but
early
reduction
credits
could
be
earned
for
installing
Hg­
specific
control
equipment.
A
second
phase
would
begin
in
2015
with
a
cap
of
24
tons
of
Hg
per
year.
In
the
second
phase,
Hg
allowances
would
be
allocated
and
Hg
trading
would
occur.
The
third
phase
would
begin
in
2018
with
a
cap
of
15
tons
per
year.

Under
this
industry
proposal,
the
first
phase
cap
could
not
be
set
at
a
level
below
the
true
co­
benefits
level;
thus,
the
amount
of
banking
could
be
expected
to
be
less.
Indeed,
the
only
credits
that
would
be
accrued
from
2010
to
2015
would
be
those
associated
with
the
early
installation
of
Hg
control
equipment.
Providing
for
early
reduction
credits
would
foster
early
reductions
in
Hg
emissions
and
assist
in
identifying
and
solving
technical
issues
that
will
undoubtedly
arise
when
a
new
technology
is
installed.
Beginning
the
second
phase
in
2015
 
only
three
years
before
the
proposed
third­
phase
15­
ton
cap
would
take
effect
 
would
limit
the
period
during
which
allowances
could
be
banked,
making
it
likely
that
full
achievement
of
the
third
phase
cap
emission
limit
would
occur
in
or
not
long
after
2018.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.
EPA
is
not
including
a
provision
for
early
reduction
credits
in
the
final
rulemaking.
See
Chapter
5
response
to
comments
for
further
discussion
of
ERCs.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
the
EPMM
model
runs
reported
in
the
commenter's
earlier
submission
(
see
OAR­
2002­
0056­
2929)
projected
that
emissions
of
Hg
would
reach
the
level
of
the
Phase
II
cap
of
15
tons
by
2020.
It
has
been
widely
reported
that
EPA's
analysis
of
the
same
scenario
using
its
own
assumptions
and
the
IPM
model
did
not
come
close
to
reaching
the
level
of
the
Phase
II
by
2020,
or
even
by
the
end
of
its
2026
model
period.
CRA's
report,
submitted
with
the
commenter's
comments,
provided
an
explanation
of
the
likely
reasons
for
EPA's
assumptions
to
have
produced
such
a
different
glide
path
for
the
same
scenario.
There
were
three
basic
reasons:
9­
111
1.
EPA
set
the
Phase
I
cap
at
34
tons,
which
was
equal
to
"
co­
benefits"
under
EPA's
modeling
assumptions.
Industry's
assumptions
implied
that
"
co­
benefits"
were
substantially
higher,
at
39.9
tons.
The
main
reasons
for
these
differences
in
co­
benefits
were:

a.
EPA
assumed
greater
incremental
Hg
control
resulting
from
addition
of
FGD,
and
from
adding
SCRs
to
units
with
FGDs
as
well,
particularly
for
subbituminous
coals,
but
also
for
FGDs
added
at
bituminous­
fired
units.
b.
Even
without
consideration
of
the
Hg
co­
benefits
from
FGDs,
EPA's
assumptions
led
to
a
greater
propensity
to
meet
SO
2
caps
through
capital­
intensive
FGDs
rather
than
through
use
of
lower­
sulfur
coals.

2.
EPA's
marginal
cost
curve
for
addition
of
ACIs
(
to
achieve
Hg
controls
beyond
the
cobenefits
level)
was
higher
and
steeper
than
the
technological
cost
and
effectiveness
assumptions
used
by
industry.

The
commenter
noted
that
CRA
explained
how
the
net
impact
of
these
differences
in
assumptions
was
that
EPA's
model
would
find
it
cost­
effective
to
bank
much
larger
amounts
during
Phase
I
of
the
proposed
Hg
cap­
and­
trade
policy
option
(
when
reductions
could
be
met
largely
via
co­
benefits
that
were
relatively
cheap
compared
to
those
assumed
by
industry)
and
to
avoid
for
a
relatively
longer
time
the
deeper
cuts
of
Phase
II
(
which
would
require
ACI
investments
that
were
relatively
more
expensive
than
assumed
by
industry).
In
other
words,
when
the
Phase
I
cap
is
set
closer
to
co­
benefits,
the
glide
path
to
the
final
level
of
the
cap
will
be
more
extended
during
Phase
II.
The
more
costly
the
Phase
II
cap
is
to
meet,
the
more
extended
the
glide
path
will
be
(
i.
e.,
more
banking
will
occur
in
Phase
I,
thus
lengthening
the
period
of
time
until
emissions
would
reach
the
final
cap).
By
setting
the
Phase
I
cap
at
its
model's
estimated
level
of
co­
benefits,
and
having
a
Phase
II
cap
that
would
be
relatively
expensive
to
meet,
EPA's
was
maximizing
the
chances
that
its
model
would
project
a
long
delay
before
annual
emissions
near
the
Phase
II
cap.

Industry
analyses
did
not
find
this
to
be
a
realistic
glide
path
if
the
cap
were
to
be
set
at
34
tons,
for
the
simple
reason
that
industry's
data
indicate
that
a
34
ton
cap
would
be
far
below
the
low­
cost
zone
of
co­
benefits,
and
so
the
Phase
I
cap
would
quite
expensive
to
meet
in
its
own
right.
Thus,
far
less
banking
would
be
warranted
in
Phase
I,
and
industry
projects
a
quicker
glide
path
to
the
proposed
Phase
II
cap,
with
a
much
smaller
bank
to
deplete,
and
thus
relatively
prompt
attainment
of
the
actual
level
of
the
Phase
II
cap.

The
commenter
stated
that
in
response
to
the
NODA,
CRA
has
prepared
a
number
of
additional
sensitivity
cases
using
EPMM
to
substantiate
the
above
logic,
and
to
better
elucidate
the
particular
parameters
that
might
most
alter
the
length
of
the
glide
path
to
a
Phase
II
cap.
The
commenter
explored
the
role
of
(
a)
uncertainties
in
EPMM
assumptions
that
fundamentally
determine
the
co­
benefits
level;
(
b)
the
stringency
of
the
Phase
II
cap
relative
to
the
Phase
I
cap;
(
c)
impact
of
setting
the
Phase
I
cap
closer
to
the
expected
level
of
co­
benefits;
(
d)
shortening
the
duration
of
Phase
I,
with
alternative
assumptions
about
the
timing
and
phase­
in
of
an
ultimate
15
ton
cap;
and
(
e)
the
role
of
rate
of
technological
improvement.
Except
where
noted,
all
of
the
runs
described
in
this
section
were
prepared
with
the
extended
version
of
EPMM
that
includes
a
terminal
model
period
at
2030.
Thus,
the
2020
emissions
results
that
the
commenter
reported
9­
112
here
are
not
from
a
terminal
period.
Also,
all
of
the
runs
assume
a
2.5
percent
per
annum
(
p.
a).
reduction
in
the
variable
cost
of
Hg
control
technologies
except
where
the
commenter
specifically
explore
the
role
of
alternative
assumptions
about
technological
change
(
in
Section
III,
see
Document
ID
No.
OAR­
2002­
0056­
5469).

The
commenter
found
that
the
most
important
determinants
of
the
glide
path
are
how
close
the
Phase
I
cap
is
to
the
level
of
co­
benefits,
and
the
duration
of
Phase
I.
These
have
the
most
direct
connection
to
the
size
of
the
bank
that
can
be
built
up
at
relatively
low
cost
prior
to
entry
into
Phase
II,
and
that,
in
turn,
most
directly
affects
the
length
of
time
before
annual
emissions
must
actually
be
at
the
Phase
II
cap.
The
commenter
also
found
that
the
effects
on
the
glide
path
of
setting
a
Phase
I
cap
set
at
or
near
co­
benefits
levels
can
be
offset
effectively
by
an
earlier
introduction
of
Phase
II,
or
even
an
interim
cap
before
the
15
ton
level.
This
two­
pronged
adjustment
to
the
proposed
Hg
cap
appears
to
strike
a
good
balance
between
a
reasonable
rate
of
introduction
of
new
Hg
control
technology
that
can
maximize
the
potential
benefits
of
technological
advancement,
and
avoiding
significant
delays
in
when
actual
annual
emissions
would
be
at
the
level
of
the
15
ton
cap.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
EPA
has
examined
the
commenter's
analysis
and
notes
that
its
own
analysis
shows
a
more
gradual
emission
glide
path
in
meeting
the
second
phase
cap.
See
Chapter
7
of
final
rule
RIA
for
further
discussion
of
EPA
emissions
projections.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
they
previously
identified
uncertainty
in
the
amount
of
FGD
that
would
be
installed
versus
use
of
lower­
sulfur
coals
to
meet
SO
2
caps
as
one
of
the
possible
uncertainties
in
our
estimate
of
co­
benefits.
One
assumption
in
EPMM
that
might
affect
the
mix
of
SO
2
compliance
choices
regards
the
availability
of
lower­
sulfur
coals.
The
standard
EPMM
assumptions
have
been
to
allow
up
to
2
percent
p.
a.
growth
in
use
of
coals
in
each
of
several
coal
quality
categories.
However,
recent
experiences
in
coal
markets
have
suggested
that
the
lowest­
sulfur
forms
of
Eastern
bituminous
coals
may
not
have
even
that
much
potential
for
growth
in
supply
without
major
cost
increases.

The
commenter
decided
to
look
at
how
the
FGD
choices
might
be
adjusted
if
this
coal
were
only
allowed
to
grow
at
0.5
percent
p.
a.
All
other
coals
continued
to
face
2
percent
p.
a.
growth
limits,
except
for
the
high­
sulfur
bituminous
coals,
which
were
no
longer
constrained
at
all.
This
run
did
produce
a
fairly
dramatic
increase
in
the
quantity
of
FGDs
installed
by
2010,
and
a
correspondingly
lower
co­
benefits
level.
In
2010,
it
projects
a
co­
benefits
level
of
38.9
tons,
as
compared
to
40
tons
under
our
standard
coal
growth
assumptions.
While
there
are
more
FGDs
in
this
case,
there
is
a
more
gradual
introduction
of
ACIs.
The
net
effect
is
only
a
very
modest
change
in
the
glide
path.
Emissions
in
2020
are
at
15.6
tons,
compared
to
15.4
tons
in
the
standard
case
reported
in
Section
I.
A.
(
see
OAR­
2002­
0056­
5469).

This
scenario
suggests
that
the
role
of
a
preference
for
FGD
in
determining
co­
benefits
9­
113
and
a
glide
path
to
Phase
II
may
be
fairly
minor.
The
commenter
found
that
industry's
estimate
of
2010
co­
benefits
might
be
as
low
as
38.9
tons,
rather
than
the
39.9
tons
originally
reported
(
which
is
now
estimated
at
40.0
tons
using
the
version
of
EPMM
with
the
extended
model
horizon).
This
difference
does
not
affect
the
estimated
present
value
cost
of
the
Hg
cap­
and­
trade
proposal,
which
is
$
1.8
billion
(
1999
dollars)
for
both
the
lower
or
higher
assumptions
about
low­
sulfur
bituminous
coal
availability.

Another
area
of
substantial
uncertainty
on
co­
benefits
relates
to
the
specific
assumptions
that
are
made
about
the
reductions
that
are
associated
with
different
configurations
of
PM,
SO
2,
and
NO
x
controls.
In
particular,
there
has
been
much
debate
over
whether
SCRs
produce
additional
Hg
reduction
when
added
to
units
with
an
FGD
that
are
burning
a
lower
rank
coal.
EPRI
reports
in
its
comments
on
the
NODA
that
there
may
be
some
new
evidence
that
there
could
be
a
very
small
amount
of
co­
benefits
in
such
units.
Although
the
evidence
is
from
a
single
plant,
and
may
not
apply
to
all
low­
rank
configurations,
the
commenter
tested
the
effect
of
adding
a
5
percent
co­
benefit
from
SCR
to
all
subbituminous
and
lignite­
burning
plants.
This
had
almost
no
impact
at
all
on
our
co­
benefits
estimates:
the
40.0
ton
estimate
from
the
base
model
was
reduced
to
39.9
tons.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
EPA
agrees
that
different
modeling
assumptions
can
impact
the
projection
Hg
cobenefits
from
NOx
and
SO2
controls
under
CAIR.
As
discussed
in
the
NODA,
for
the
final
rulemaking
analysis,
EPA
has
made
changes
to
some
of
its
co­
benefit
assumptions
for
subbituminous
units
with
SCR
and
FGD
controls.
EPA
is
also
using
a
newer
version
of
EPA's
IPM
for
the
final
rulemaking.
Changes
to
the
modeling
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).
EPA
has
examined
the
commenter's
analysis
and
notes
that
its
own
analysis
shows
a
more
gradual
emission
glide
path
in
meeting
the
second
phase
cap.
See
Chapter
7
of
final
rule
RIA
for
further
discussion
of
EPA
emissions
projections.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
noted
that
another
possible
factor
that
the
commenter
posited
could
lengthen
the
glide
path
is
how
stringently
the
Phase
II
cap
is
set
relative
to
the
stringency
of
the
Phase
I
cap.
To
explore
this
possibility,
the
commenter
considered
the
impacts
of
a
Phase
II
cap
set
at
7.5
tons
rather
than
15
tons,
while
keeping
the
Phase
I
cap
at
34
tons,
the
presumed
level
of
the
proposed
Clean
Air
Mercury
Rule
(
CAMR).
This
would
have
the
effect
of
making
the
marginal
cost
of
meeting
the
Phase
II
cap
once
the
bank
is
depleted
much
more
costly
relative
to
the
marginal
costs
of
exactly
meeting
the
Phase
I
cap.
The
result
should
be
an
incentive
to
bank
more
during
Phase
I,
in
order
to
reduce
the
rate
of
increase
of
marginal
costs
of
control
(
also
called
emissions
prices)
back
to
about
the
corporate
discount
rate.
If
this
were
to
happen,
the
glide
path
to
the
Phase
II
cap
would
be
lengthened.

This
is
exactly
what
the
commenter
found
in
this
scenario.
The
marginal
costs,
Hg
9­
114
emissions,
and
cumulative
amount
of
Hg
emissions
banked
are
shown
in
Table
4.
The
most
dramatic
effect
of
this
scenario
is
that
Phase
II
is
not
only
delayed
beyond
2020,
but
projected
emissions
are
still
well
above
the
Phase
II
cap
through
the
end
of
the
terminal
model
period:
projected
emissions
in
2020­
2029
are
11
tons,
and
they
are
still
9.3
tons
for
the
entire
period
2030­
2049.
The
7.5
ton
cap
is
never
fully
met
until
the
first
year
after
the
model
stops
accounting
for
costs
of
control,
in
2050.
This
delay
is
accomplished
by
accumulating
a
bank
exceeding
86
tons
during
Phase
1.
Even
with
this
lengthy
delaying
action,
the
marginal
cost
of
controls
in
2020
is
over
$
45,000/
lb
(
1999
dollars).

The
commenter
also
found
that
the
7.5
ton
Phase
II
cap
increases
the
present
value
of
the
policy's
cost
quite
significantly.
Our
estimated
present
value
(
through
2020)
of
costs
of
the
proposed
Hg
cap­
and­
trade
policy
is
$
1.8
billion
(
1999
dollars).
With
the
same
assumptions,
a
7.5
ton
cap
in
Phase
II
is
estimated
to
be
$
4.6
billion.
Tightening
the
Phase
II
cap
in
2018
from
15
tons
to
7.5
tons
increases
policy
costs
by
160
percent.

Table
4.
Results
of
Scenario
with
7.5
ton
Phase
II
Cap
in
2018
Hg
Emissions
(
tons
per
year)
Hg
Bank
at
Beginning
of
Period
(
tons)
Marginal
cost
of
Hg
controls
in
Period
2004
44.6
na
na
2008
43.1
na
na
2010
28.3
0.0
$
25,691
2012
23.6
11.3
$
28,872
2015
19.3
42.4
$
34,435
2018
15.4
86.6
$
41,098
2020
11.0
70.9
$
45,586
2030
9.3
35.6
$
99,693
The
commenter
also
ran
a
case
where
no
banking
was
allowed
during
Phase
I,
thus
forcing
the
model
to
actually
meet
the
7.5
ton
cap
in
2018
and
thereafter.
The
purpose
of
this
was
to
determine
the
sensitivity
of
marginal
costs
to
a
cap
of
7.5
tons.
This
case
produced
marginal
control
costs
of
$
120,000/
lb
in
2018,
and
$
94,000/
lb
in
2020
(
both
1999
dollars).
The
falling
marginal
control
cost
reflects
the
effect
of
the
2.5
percent
p.
a.
decline
in
variable
O&
M
costs
of
ACI.
This
rate
of
decline
is
not
insignificant,
but
certainly
insufficient
to
make
attainment
of
a
7.5
ton
cap
occur
without
very
high
allowance
prices.

The
stringency
of
the
7.5
ton
cap
also
is
reflected
in
terms
of
its
implications
for
retrofitting.
When
the
7.5
ton
cap
is
met
in
2018,
fully
78
percent
of
existing
coal
capacity
has
been
retrofitted
by
ACI
at
90
percent
controls,
in
addition
to
the
usual
large
number
of
FGD
and
SCR
installations
(
about
107
GW
and
56
GW
of
additional
FGDs
and
SCRs,
respectively,
are
also
added
by
2018).
Clearly
most
plants
are
installing
ACI
as
well
as
FGDs
and
SCRs.

The
commenter
found
that
this
was
a
particularly
interesting
scenario
in
light
of
the
comments
that
were
submitted
to
EPA
in
June
2004
by
the
Center
for
Clean
Air
Policy
(
CCAP),
and
which
were
summarized
in
the
NODA.
The
NODA
summarizes
CCAP's
views
based
on
a
comparable
model
run
with
IPM
as
"
concluding
that
the
incremental
changes
in
the
timing
and
9­
115
stringency
of
a
Hg
cap
have,
in
CCAP's
opinion,
relatively
modest
cost
implications."
The
commenter
reviewed
the
detailed
results
of
CCAP's
runs,
and
found
that
our
results
are
actually
very
similar
to
those
found
by
CCAP
for
the
7.5
ton
cap
case:

°
CCAP's
scenario
for
a
7.5
ton
cap
in
Phase
II
(
with
Phase
I
banking)
projects
that
emissions
in
2020­
2025
would
still
be
11.3
tons
and
the
marginal
cost
of
control
in
2020
would
be
$
88,060/
lb
(
1999
dollars).

°
CCAP's
results
for
a
7.5
ton
cap
in
Phase
II
(
with
no
Phase
I
banking)
projects
that
the
marginal
cost
of
meeting
the
7.5
ton
cap
would
be
$
165,500/
lb
in
2018
and
$
129,500
in
2020
(
1999
dollars).

°
CCAP's
costs
of
having
a
more
stringent
7.5
ton
cap
in
2015
is
also
at
least
150
percent
more
costly
than
a
15
ton
cap
in
2018,
even
based
on
much
lower
EPA
gas
price
assumptions.

In
brief,
CCAP's
analysis
finds
the
7.5
ton
cap
more
costly
to
achieve
than
does
CRA's
analysis.
There
is
obviously
a
"
knee
in
the
curve"
of
the
marginal
control
costs
at
a
cap
level
greater
than
7.5
tons.
The
commenter
therefore
conclude
that
EPA's
interpretation
of
the
CCAP
results,
that
the
timing
and
stringency
of
the
Hg
cap
"
have
relatively
modest
cost
implications"
is
a
judgment
that
the
commenter
found
inconsistent
with
CCAP's
own
modeling
results.

CCAP
reports
that
it
considered
alternative
levels
of
the
Phase
II
cap
in
an
effort
to
"
identify
a
possible
middle
ground
solution...
in
which
a
less
stringent
Phase
I
target
is
traded
off
against
a
more
stringent
Phase
2
target."
The
commenter's
analyses
suggested
that
increasing
the
stringency
of
the
Phase
II
cap
can
be
counterproductive.
It
can
delay
attainment
of
the
Phase
II
cap
for
extended
periods,
while
creating
a
much
more
rapid
rate
of
investment
in
the
emerging
technology
that
may
exacerbate
efforts
for
a
measured
and
cost­
effective
phase­
in
process.
If
one
goal
is
to
design
a
policy
that
will
enable
a
gradual
phase­
in
of
investments
in
emerging
forms
of
control
technology,
thereby
maximizing
the
opportunities
and
incentives
for
technological
improvements
to
be
gained,
then
it
does
not
make
sense
to
have
a
stringent
Phase
I
cap,
but
it
also
does
not
make
sense
for
the
Phase
II
cap
to
be
very
stringent
relative
to
the
Phase
I
cap.
A
proposal
for
a
cap
as
tight
7.5
tons
is
inconsistent
with
CCAP's
much
more
important
point,
that
a
gradual
phase
in
period,
and
incentives
for
early
action
are
desirable
elements
of
a
sound
policy
where
a
control
technology
is
still
in
an
emergent
stage.

Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
stated
that
there
are
some
important
merits
to
setting
the
Phase
I
cap
at
a
level
close
to
the
"
true"
co­
benefits
levels.
Most
importantly,
development,
testing,
and
commercialization
of
Hg
control
technology
for
electric
generating
9­
116
units
is
still
at
an
early
stage.
The
difficulties
of
achieving
various
levels
of
Hg
control
across
the
universe
of
generating
units
are
highly
uncertain
and
there
is
little
if
any
experience
with
commercial
installation.
Because
of
this,
rates
of
technological
improvement
in
the
technology
are
very
high
and
a
gradual
phase­
in
helps
motivate
more
intensive
research,
while
also
enhancing
potential
for
carrying
the
learning
from
the
first
several
installations
into
the
wider
set
of
installations
that
will
come
with
time.
At
the
same
time,
there
is
a
risk
that
setting
the
Phase
I
cap
at
the
"
true"
co­
benefits
level
will
create
a
longer­
than­
desirable
glide
path
will
be
to
the
Phase
II
cap
level.

Below,
the
commenter
discussed
results
of
a
couple
of
scenarios
evaluated
to
substantiate
this
point,
and
then
the
commenter
turned
to
an
alternative
that
more
effectively
resolves
the
glide
path
concern
while
preserving
the
benefits
of
setting
Phase
I
cap
at
the
"
true"
co­
benefits
level
(
see
OAR­
2002­
0056­
5469).

In
CRA's
analyses,
the
"
true"
level
of
co­
benefits
emissions
in
2010
is
either
38.8
tons
or
40
tons.
It
is
38.8
tons
in
2010
under
the
assumption
of
0.5
percent
maximum
annual
growth
in
low­
sulfur
bituminous
coal,
and
it
is
40
tons
in
2010
under
the
assumption
of
2
percent
maximum
annual
growth
in
the
same.
The
commenter's
analyses
of
EPA's
proposed
cap­
and­
trade
policy
option,
however,
have
used
34
tons
as
the
Phase
I
cap.
The
commenter
had
used
this
value
because
EPA
stated
in
its
notice
of
proposed
rulemaking
that
it
would
set
the
Phase
I
cap
at
the
co­
benefits
level,
and
also
that
it
estimated
co­
benefits
to
be
34
tons.
A
cap
must
be
set
at
a
welldefined
level,
and
cannot
vary
depending
on
one's
views
about
what
might
constitute
the
intended
goal
of
co­
benefits.
Although
34
tons
was
not
the
"
true"
co­
benefits
level
in
our
model,
there
is
no
reason
to
believe
that
EPA
would
select
a
Phase
I
cap
at
any
level
other
than
what
it
estimated
as
"
true"
co­
benefits
(
see
OAR­
2002­
0056­
5469).

The
commenter
noted
in
our
earlier
submissions
that
EPA's
projected
glide
path
would
be
much
longer
than
that
projected
by
EPMM
because
the
34
ton
cap
was
achievable
solely
by
"
true"
co­
benefits
in
EPA's
modeling,
but
was
much
lower
than
the
EPMM
co­
benefits
level,
and
therefore
more
costly
to
meet
in
CRA's
modeling.
EPA's
model
would
thus
project
much
more
banking
in
Phase
I
than
would
EPMM,
thereby
delaying
full
implementation
of
Phase
II
emissions
levels
in
the
Agency's
runs.
In
the
current
analysis,
the
commenter
simulated
this
effect
in
the
EPMM
model
by
running
scenarios
where
the
commenter
set
the
Phase
I
cap
at
EPMM's
projected
co­
benefits
levels,
for
the
two
sets
of
coal
assumptions,
respectively.
The
commenter
left
the
Phase
II
cap
at
15
tons,
since
this
value
appeared
to
have
no
connection
to
particular
model
assumptions.

Tables
5
and
6
contrast
the
timing
of
ACI
and
FGD
installations,
respectively,
for
the
case
of
Phase
I
being
set
by
the
co­
benefits
level,
and
the
case
of
Phase
I
being
set
at
a
34
ton
cap.
Figure
3
presents
the
glide
paths
of
Hg
emissions
for
both
coal
constraint
cases.
The
predicted
effect
on
the
glide
path
is
apparent.
Projected
emissions
remain
2
tons
above
the
Phase
II
cap
until
2030
in
the
case
where
the
Phase
I
cap
is
set
at
co­
benefits.
This
is
the
largest
single
source
of
glide
path
sensitivity
that
the
commenter
had
found
for
a
15
ton
Phase
II
cap.
It
would
appear
to
explain
much
of
the
difference
between
the
CRA
projections
of
2020
emissions
reaching
the
national
target
level,
and
the
more
extended
period
to
reach
that
target
that
has
been
reported
as
the
EPA
finding.
9­
117
As
noted,
the
advantage
of
a
cap
at
co­
benefits
levels
in
the
early
years
is
that
it
creates
a
better
environment
for
a
gradual
and
non­
disruptive
commercial
phase­
in
of
a
technology
that
can
best
be
described
as
still
emergent.
By
setting
the
cap
at
this
level,
one
creates
desirable
incentives
for
early
action
by
allowing
banking
to
occur.
However,
if
the
cap
remains
at
the
cobenefit
level
for
an
extended
period
of
time,
a
relatively
large
bank
may
be
possible
to
build
up.
This
implies
benefits
from
early
reductions,
but
at
the
same
time,
it
means
that
the
rate
of
decrease
towards
the
Phase
II
cap
will
be
slowed.
The
best
way
to
preserve
the
merits
of
a
cap
set
at
cobenefits
level,
while
managing
for
a
relatively
prompt
attainment
of
Phase
II
is
to
alter
the
length
of
Phase
I.
The
next
section
turns
to
this
prospect,
exploring
how
the
glide
path
can
be
managed
while
still
setting
the
Phase
I
cap
set
at
the
estimated
co­
benefits
level.

Table
5.
Quantities
of
New
ACI
Retrofits
by
Time
Period
(
MW)

Year
Standard
Low­
S
Coal
Assumptions
(
2010
co­
benefits=
40
tons)
Low
Supply
Growth
of
Low­
S
Bituminous
(
2010
co­
benefits=
38.8
tons)

Proposed
Policy:
Phase
I
cap
at
34
tons
Phase
I
cap
at
cobenefits
Proposed
Policy:
Phase
I
cap
at
34
tons
Phase
I
cap
at
cobenefits
2004
1,050
244
1,050
244
2008
1
1
1
1
2010
16,835
4,537
11,660
5,679
2012
1,352
3,442
22,220
511
2015
16,398
11,092
19,848
15,158
2018
23,646
26,373
48,238
19,326
2020
49,079
51,067
22,220
56,514
2030
5,695
17,679
8,084
17,745
Table
6.
Quantities
of
New
FGD
Retrofits
by
Time
Period
(
MW)

Year
Standard
Low­
S
Coal
Assumptions
(
2010
co­
benefits=
40
tons)
Low
Supply
Growth
of
Low­
S
Bituminous
(
2010
co­
benefits=
38.8
tons)

Proposed
Policy:
Phase
I
cap
at
34
tons
Phase
I
cap
at
cobenefits
Proposed
Policy:
Phase
I
cap
at
34
tons
Phase
I
cap
at
cobenefits
2004
1,315
2,983
5,227
4,907
2008
8,159
5,936
6,907
6,677
2010
32,791
26,517
42,537
40,048
2012
13,678
19,816
6,457
8,686
2015
3,444
4,041
5,112
5,458
2018
12,024
10,710
17,893
17,481
2020
31,103
32,437
33,736
34,475
Year
Standard
Low­
S
Coal
Assumptions
(
2010
co­
benefits=
40
tons)
Low
Supply
Growth
of
Low­
S
Bituminous
(
2010
co­
benefits=
38.8
tons)

Proposed
Policy:
Phase
I
cap
at
34
tons
Phase
I
cap
at
cobenefits
Proposed
Policy:
Phase
I
cap
at
34
tons
Phase
I
cap
at
cobenefits
9­
118
2030
15,330
16,187
9,511
10,219
Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
emissions
projections.

Comment:

One
commenter
(
OAR­
2002­
0056­
5469)
stated
that
four
(
4)
additional
scenarios
were
run
that
explored
alternative
timings
of
a
Phase
II
cap
that
might
be
paired
with
a
Phase
I
cap
set
at
"
true"
co­
benefits.
Two
scenarios
were
run
assuming
that
the
Phase
II
cap
is
implemented
in
2015
instead
of
2018
(
one
for
each
set
of
coal
supply
assumptions,
and
hence
with
different
assumptions
about
co­
benefits,
to
match
the
two
scenarios
described
in
comment
above).
The
other
two
scenarios
are
the
"
Alternative
Cap
Proposal"
(
see
OAR­
2002­
0056­
4894)
that
9­
119
commenter
submitted
to
EPA
on
August
13,
2004
for
each
co­
benefits
case.
This
alternative
proposal
would
strike
an
intermediate
ground
by
tightening
the
cap
in
the
period
2015­
2017,
but
only
to
24
tons,
with
the
15
ton
cap
following
in
2018.

Figure
4
compares
the
glide
path
of
each
of
these
four
scenarios
to
those
in
the
previous
section
where
the
commenter
set
the
cap
at
co­
benefits
in
Phase
I,
but
still
allowing
Phase
II
to
enter
force
in
2018.
Table
7
shows
the
associated
quantities
of
ACI
controls
in
each
time
step,
which
can
be
compared
to
the
values
in
Table
5
as
well.
The
early
introduction
of
Phase
II
increases
the
rate
of
early
action
in
Phase
I,
but
still
gets
emissions
to
15
tons
by
2020.
However,
the
commenter's
proposed
alternative
scenario,
with
an
intermediate
cap
at
24
tons,
provides
a
similar
reduction
by
2020,
but
with
a
slower
rate
of
investments
in
the
early
years,
when
the
costs
of
control
are
the
most
uncertain.

The
estimated
costs
are
fairly
sensitive
to
the
decision
on
level
of
the
cap
during
2015­
2017.
As
a
point
of
reference,
the
estimated
present
value
of
the
Hg
cap
as
proposed
(
i.
e.,
34
tons
in
Phase
I,
and
Phase
II
starting
in
2018)
is
$
1.8
billion
(
1999
dollars).
By
allowing
the
Phase
I
cap
to
be
set
at
co­
benefits
(
as
determined
by
the
model),
but
continuing
to
keep
Phase
II
in
2018,
costs
would
fall
to
about
$
1.2
or
1.3
billion,
and
attainment
of
the
Phase
II
cap
could
be
delayed
well
beyond
2020.
By
introducing
the
15
ton
cap
in
2015,
costs
would
increase
to
about
$
2.6
or
2.8
billion,
although
emissions
would
be
at
15
tons
by
2020.
In
contrast,
the
alternative
proposed
by
the
commenter,
would
cost
only
$
1.8
or
1.9
billion,
and
would
still
provide
assurance
of
attainment
of
the
15
ton
emissions
level
by
about
2020.

Thus,
a
combination
of
a
co­
benefits
based
cap
in
Phase
I
with
a
shorter
duration
of
Phase
I
provides
better
assurance
against
excessive
costs
during
program
start­
up,
as
well
as
better
assurance
of
reaching
the
15
ton
emission
level
somewhere
in
the
2020
time
frame.
If
interim
caps
are
used
instead
of
bluntly
moving
the
15
ton
cap
forward
in
time,
the
policy
costs
need
not
increase,
while
still
providing
assurance
of
timely
attainment
of
the
15
ton
level
of
emissions.

The
commenter's
alternative
cap
proposal
is
very
similar
in
nature
to
the
simplistic
sensitivity
case
that
simply
brings
in
a
15
ton
cap
by
2015.
It
has
the
same
properties
of
requiring
only
cost­
effective
early
action
through
2015,
yet
bringing
emissions
to
15
tons
promptly.
The
mechanism
for
accomplishing
this
effect
was
the
same:
by
tightening
the
cap
in
2015
in
such
a
way
that
an
allowance
bank
would
not
continue
to
accumulate
at
increasing
rates
for
three
additional
years
before
the
imposition
of
Phase
II.
The
main
differences
of
the
alternative
proposed
policy
from
simply
introducing
the
Phase
II
cap
by
2015
are:

°
Under
the
commenter's
proposed
alternative
there
would
be
no
formally
binding
cap
in
the
2010­
2015
time
frame,
providing
further
guarantees
that
early
reductions
would
be
9­
120
Table
7.
Quantities
of
New
ACI
Retrofits
by
Time
Period
(
MW)
With
Phase
I
Cap
Set
at
Co­
benefits
Level,
for
Alternative
Timings
of
Phase
II
Cap
Year
Standard
Low­
S
Coal
Assumptions
(
2010
co­
benefits
=
40
tons)
Low
Supply
Growth
of
Low­
S
Bituminous
(
2010
co­
benefits
=
38.8
tons)

15
ton
cap
by
2015
24
ton
cap
in
2015­
2017
15
ton
cap
by
2015
24
ton
cap
in
2015­
2017
2004
1,050
1,050
1,050
1,050
2008
1
1
1
1
2010
18,189
6,491
18,892
7,424
2012
15,715
12,029
18,204
14,466
2015
31,126
27,590
24,294
22,274
2018
17,417
23,780
22,792
26,686
2020
27,004
39,080
26,905
37,341
2030
4,044
5,024
2,902
5,469
against
literal
co­
benefits
rather
than
against
an
inherently
uncertain
estimate
of
what
that
co­
benefit
level
would
be.
From
a
modeling
perspective,
where
no
uncertainties
are
simulated,
this
would
have
no
impact
on
our
results,
but
it
obviously
does
have
relevance
to
consideration
of
cost
risks.
9­
121
°
Another
difference
that
remains
open
to
deliberation
is
the
precise
level
of
the
cap
in
the
2015­
2017
period.
In
one
sensitivity
case
the
commenter
used
15
tons,
whereas
the
alternative
proposal
by
the
commenter
allows
it
to
be
24
tons,
substantially
less
stringent.
The
correct
level
to
choose
for
the
interim
cap
could
be
informed
by
whether
it
significantly
alters
the
timing
of
attainment
of
the
15
ton
emissions
goal.
The
commenter's
analyses
indicate
that
a
24
ton
cap
in
2015
would
ensure
the
prospects
of
prompt
attainment
of
the
15­
ton
goal
while
maintaining
a
relatively
gradual
rate
of
Hg
control
investments
during
Phase
I
and
keeping
policy
costs
low.

It
is
important
to
note
that
the
modest
impacts
on
costs
from
an
early
introduction
of
Phase
II
only
occur
when
this
acceleration
is
combined
with
a
Phase
I
period
that
is
truly
set
at
co­
benefits
(
either
by
providing
early
reduction
credits
or
by
setting
the
cap
at
an
accurate
estimate
of
the
literal
co­
benefits
level).
Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
modeling
analysis.

7.
Cinergy
estimated
a
co­
benefit
of
Hg
reductions
associated
with
implementation
of
the
proposed
CAIR
at
38
tons
in
2010;
EEI
Estimated
a
co­
benefit
level
of
40
tons
in
2010.
EPA
additional
comment
on
the
reasonableness
of
its
IPM
assumptions
for
co­
benefit
reductions.
EPA
also
sought
comment
on
appropriate
emission
modification
factors
(
EMF)
 
a
component
of
the
estimated
Hg
co­
benefit
reductions.

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
believed
the
modeled
cost
estimates
were
too
high
and
the
assumptions
of
co­
benefits
from
the
proposed
Clean
Air
Interstate
Rule
were
lower
than
even
EPA's
projections.

Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
modeling
analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5332)
stated
that
EPA
requests
comments
on
the
"
co­
benefits"
of
Hg
reductions
associatewith
implementation
of
the
proposed
CAIR.
This
issue
is
extremely
important,
as
EPA
is
proposing
to
establish
the
Hg
co­
benefits
level
as
the
first­
phase
9­
122
emission
limitation
of
its
section
111
proposal.

Initially,
the
Agency
had
estimated
a
Hg
co­
benefits
level
of
26
tons
(
down
from
48
tons);
that
is,
it
estimated
that
air
pollution
control
devices
installed
to
reduce
the
emissions
of
pollutants
other
than
Hg
from
coal­
fired
units
would
reduce
Hg
emissions
by
22
tons,
resulting
in
the
incidental
reduction
of
Hg
emissions
to
a
level
of
26
tons.
Based
apparently
on
subsequent
revisions
to
its
modeling
assumptions,
EPA
increased
the
co­
benefits
level
to
the
current
estimate
of
34
tons;
that
is,
it
concluded
that
incidental
Hg
removal
would
be
less
than
originally
estimated,
14
tons
rather
than
22
tons.
Now,
some
stakeholders
are
suggesting
that
the
co­
benefits
level
should
be
raised
to
something
closer
to
40
tons,
meaning
that
incidental
Hg
reductions
would
be
even
lower
(
only
eight
tons).
Apart
from
the
technical
justification
or
lack
thereof
for
this
co­
benefits
level
(
see
discussion
below),
the
commenter
noted
that
a
cap­
and­
trade
program
with
a
40­
ton
cap
would
free
a
great
many
sources
from
the
need
to
make
any
reduction
at
all
in
their
emissions
of
Hg.
It
would
also
allow
many
sources
easily
to
over
control
in
Phase
I,
bank
the
excess
allowances,
and
use
the
banked
allowances
in
future
control
years.
This
would
push
back
the
time
that
the
Phase
II
cap
will
ultimately
be
achieved
even
further
than
is
the
case
under
EPA's
currently
proposed
cap­
and­
trade
proposal.

Based
on
its
modeling,
EPA
concludes
that
average
Hg
removal
from
existing
air
pollution
control
devices
across
all
coal
types
and
control
configurations
is
currently
approximately
36
percent
(
48
tons
emitted
versus
75
tons
contained
in
coal).
EPA
currently
estimates
that
with
the
controls
installed
to
comply
with
the
CAIR
proposal,
annual
Hg
emissions
from
existing
air
pollution
control
equipment
will
drop
further,
from
48
tons
to
34
tons
per
year,
which
represents
about
a
29
percent
reduction
from
current
emissions.

However,
EPA's
estimate
of
Hg
co­
benefit
levels
reflect
only
incidental
Hg
reduction
from
control
devices
designed
and
operated
to
remove
other
air
pollutants,
such
as
SO
2,
NO
x,
and
particulate
matter,
with
no
attempt
to
optimize
their
operation
for
Hg
removal.
The
commenter
believed
that
the
capture
of
Hg
by
existing
controls
can
be
increased
significantly,
simply
by
optimizing
reductions
from
equipment
installed
to
control
other
pollutants.
A
great
deal
of
work
is
being
done
on
measures
that
can
be
taken
to
optimize
Hg
reductions
from
existing
air
pollution
control
equipment,
including
the
injection
of
oxidants
(
e.
g.,
chloride)
into
flue
gas
to
promote
the
oxidation
of
elemental
Hg
from
SCR
at
units
burning
lower
rank
coals
(
which
are
typically
low
in
chloride
levels),
and
the
addition
of
chemicals
to
enhance
the
removal
of
oxidized
Hg
in
wet
FGD
systems
and
to
prevent
re­
emissions
of
Hg.

The
commenter
believed
that
the
Hg
co­
benefits
of
CAIR
should
perhaps
be
reduced
from
EPA's
current
estimate
of
34
tons;
in
other
words,
the
commenter's
view
was
that
reductions
in
Hg
emissions
achieved
as
a
co­
benefit
of
efforts
to
control
other
pollutants
are
greater
than
EPA
currently
estimates.
By
the
same
token,
the
commenter
did
not
believe
that
there
would
be
any
justification
for
increasing
the
Hg
co­
benefits
figure
to
more
than
34
tons,
as
that
would
require
the
conclusion
that
other
controls
would
not
be
as
effective
in
reducing
Hg
emissions
as
the
available
data
indicate.
9­
123
Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
emissions
projections.
As
discussed
in
the
NODA,
for
the
final
rulemaking
analysis,
EPA
has
made
changes
to
some
of
its
co­
benefit
assumptions
for
subbituminous
units
with
SCR
and
FGD
controls.
EPA
is
also
using
a
newer
version
of
EPA's
IPM
for
the
final
rulemaking.
Changes
to
the
modeling
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).

Comment:

One
commenter
(
OAR­
2002­
0056­
5446)
said
there
is
considerable
uncertainty
over
the
extent
of
"
co­
benefit"
reductions;
however
the
current
IPM
assumptions
fall
within
the
likely
range
of
co­
benefit
reductions.

Care
must
be
taken
when
assuming
co­
benefit
reductions
as
most
reductions
are
calculated
from
analysis
of
the
ICR
emissions
data
which
represent
a
limited
snapshot
of
emissions
from
a
few
units
taken
over
a
very
short
period
of
time,
with
a
limited
number
of
coals.
The
data
do
not
account
for
the
wide
variability
of
coals
and
process
conditions
encompassed
by
the
full
fleet
of
generator
boilers.
As
stated
previously
the
EPA
must
undertake
some
form
of
risk
or
probability
analysis
that
considers
variability
in
coal
properties
and
unit
performance
to
if
it
is
to
fully
understand
the
implications
of
the
proposed
rule.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
emissions
projections.
As
discussed
in
the
NODA,
for
the
final
rulemaking
analysis,
EPA
has
made
changes
to
some
of
its
co­
benefit
assumptions
for
subbituminous
units
with
SCR
and
FGD
controls.
EPA
is
also
using
a
newer
version
of
EPA's
IPM
for
the
final
rulemaking.
Changes
to
the
modeling
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
stated
that
in
regard
to
co­
benefit
reductions
(
or
corresponding
emission
modification
factors,
EMF),
the
commenter
noted
that
most
of
the
9­
124
estimates
are
based
upon
analysis
of
EPA's
1999
ICR
data
set.
The
commenter
pointed
out
in
comments
dated
May
14,
2004,
the
ICR
emissions
data
represent
a
limited
snapshot
of
emissions
from
a
few
units
taken
over
a
very
short
period
of
time,
with
a
limited
number
of
fuels.
The
data
do
not
account
for
the
wide
variability
of
coals
and
process
conditions
encompassed
by
the
full
fleet
of
utility
boilers.
As
a
result,
relatively
little
is
known
about
long­
term
Hg
emissions
performance
of
the
units
that
were
tested
or
what
may
be
achieved
through
a
broader
application
of
co­
benefit
technologies.
Because
of
the
lack
of
understanding
associated
with
the
level
of
Hg
reductions
that
will
be
achieved
through
co­
benefit
reductions
or
future
removal
technologies,
the
commenter
had
recommended
an
alternative
cap
and
trade
program.
This
alternative
would
provide
for
co­
benefit
reductions
in
the
first
phase,
coupled
with
an
assessment
of
Hg
emissions
and
performance
characteristics
of
control
technologies.
An
interim
cap
 
effective
in
2015
 
and
coal
type
allocation
adjustment
factors
would
be
based
on
this
assessment.
A
final
cap
of
15
tons
would
be
effective
2018.

The
advantages
to
this
proposal
are:
1)
it
allows
for
the
use
of
actual
emissions
data
 
as
opposed
to
speculation
about
what
may
be
achievable
in
the
future
 
in
the
setting
of
the
interim
cap
(
i.
e.,
it
provides
for
a
target
that
is
known
to
be
achievable);
2)
it
will
provide
for
a
mechanism
that
allows
EPA
to
ensure
a
balance
regulatory
approach
to
Hg
reductions
(
i.
e.,
a
rule
that
does
not
create
regional
disparities
by
advantaging
one
coal
type
over
another).
The
commenter
was
particularly
concerned
about
this
issue
because
its
members
produce
coal
in
every
coal­
producing
region
of
the
US,
and
represent
coals
of
every
rank.

Proposed
allocation
adjustment
factors
are
based
EPA's
assessment
of
the
relative
ease
with
which
Hg
can
be
removed
from
different
coal
types;
their
intent
is
to
"
level
the
playing
field."
Because
reductions
associated
with
cobenefits
are
still
not
well
understood,
and
Hg
specific
control
technologies
will
not
be
available
until
the
2010
time
frame,
the
allocation
adjustment
factors
should
not
be
set
until
EPA
has
a
better
sense
of
the
capabilities
of
these
technologies.

While
Hg
reductions
will
take
place
through
the
expanded
use
of
co­
benefit
technology
as
required
by
CAIR,
and
promising
Hg­
specific
technology
is
under
development,
it
is
premature
to
set
a
MACT,
NSPS
standard,
cap,
or
emission
allowance
allocations
because
of
the
lack
of
reliable
data
on
Hg
emissions
and
the
performance
of
control
technology.
It
would
be
arbitrary
and
unreasonable
to
base
an
emissions
standard
on
the
hypothetical
performance
of
unproven
technology.

To
the
extent
that
EPA
relies
on
EMFs
for
modeling
purposes,
those
factors
should
be
conservative
enough
to
allow
for
the
various
sources
of
variability
and
uncertainty
associated
with
co­
benefit
removal
rates
on
different
coal
types.
Where
co­
benefit
reductions
are
the
product
of
speculation
within
a
range
the
commenter
recommended
a
conservative
estimation
of
the
EMF
at
the
low
end
of
the
range;
where
evidence
exists
that
co­
benefit
reductions
are
not
being
achieved,
the
commenter
recommended
an
EMF
of
1
(
i.
e.,
no
co­
benefit
reductions).
The
commenter
noted
the
results
of
a
recent
study
conducted
by
the
Energy
and
Environmental
Research
Center
using
a
slipstream
SCR
unit
at
one
lignite­
fired
power
plant
to
determine
the
ability
of
new
and
aged
catalyst
to
oxidize
Hg.
The
results
indicate
"
limited
oxidation
of
Hg
across
the
SCR
catalyst
9­
125
when
firing
lignite
coals"
and
that
the
sulfation
of
calcium
and
sodium
ash
deposits
foul
the
catalyst
rendering
the
SCIR
 
technology
ineffective
for
NO
x
control.
An
article
describing
the
findings
has
been
accepted
for
publication
in
Fuel
Processing
Technology.
A
copy
of
the
"
article
in
press"
entitled,
"
SCR
catalyst
performance
in
flue
gases
derived
from
subbituminous
and
lignite
coals"
is
attached
(
see
e­
docket
text,
Attachment
1).

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
emissions
projections.
As
discussed
in
the
NODA,
for
the
final
rulemaking
analysis,
EPA
has
made
changes
to
some
of
its
co­
benefit
assumptions
for
subbituminous
units
with
SCR
and
FGD
controls.
EPA
is
also
using
a
newer
version
of
EPA's
IPM
for
the
final
rulemaking.
Changes
to
the
modeling
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).

EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
Overall
the
1999
Hg
ICR
data
revealed
higher
levels
of
Hg
capture
for
bituminous
coal­
fired
plants
as
compared
to
subbituminous
and
lignite
coal­
fired
plants
and
a
significant
capture
of
ionic
Hg
in
wet­
FGD
scrubbers.
Additional
Hg
testing
indicates
that
for
bituminous
coals
SCR
has
the
ability
to
convert
elemental
Hg
to
ionic
Hg
and
thus
allow
easier
capture
in
a
wet­
FGD
scrubber.
This
understanding
of
Hg
capture
was
incorporated
into
EPA
modeling
assumptions
and
is
the
basis
for
our
projections
of
Hg
co­
benefits
from
installation
of
scrubbers
and
SCR
under
CAIR.
(
For
further
discussion
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005,
in
the
docket).

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
state
that
estimated
emissions
in
2010
after
co­
benefits
of
CAIR
alone
are
realized
remain
in
the
range
of
39­
40
tons.
Variations
of
the
assumptions
in
EPMM
that
affect
its
estimate
of
co­
benefits,
accounting
for
new
information
from
the
commenter
and
other
researchers,
did
not
produce
any
significant
change
from
the
level
of
39.9
tons
that
was
reported
in
the
earlier
submittal.

Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
9­
126
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
modeling
analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5460)
stated
that
EPA
should
not
be
concerned
with
the
co­
benefits
of
Hg
reductions
associated
with
implementation
of
the
proposed
CAIR.
The
commenter
further
stated
that
EPA
is
required
to
regulate
power
plant
Hg
emissions
pursuant
to
Section
112
regardless
of
what
CAIR
may
accomplish.
The
commenter
added
that,
indeed,
it
is
required
to
do
so
promptly,
both
under
the
plain
language
of
the
Clean
Air
Act
and
under
a
consent
decree
between
EPA
and
the
Natural
Resources
Defense
Council
(
NRDC).
See
42
U.
S.
C.
§
112(
c);
OAR­
2002­
0056­
3459
(
NRDC
comments)
(
describing
consent
decree).
The
commenter
stated
that
given
these
requirements,
and
given
EPA's
own
admission
that
CAIR
may
never
become
law,
EPA
should
not
continue
to
focus
on
the
hypothetical
consequences
of
CAIR.

Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
modeling
analysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
CRA's
2004
EMF
data
(
EEI
data)
better
reflect
current
knowledge
than
EPA's,
but
should
be
modified
as
discussed
below
based
on
our
more
recent
data.
The
commenter
believed
that
EPA
must
augment
and
modify
these
EMFs
using
all
available
data
that
meet
appropriate
experimental
quality
criteria.
In
that
context,
the
commenter
reiterated
their
comment
made
on
the
initial
proposal
that
much
of
the
ICR
Part
III
emissions
data
on
which
EPA
has
relied
heavily
does
not
meet
reasonable
tests
of
data
quality
and
should
be
discounted,
if
only
to
meet
EPA's
stated
objectives
and
obligations
under
the
Data
Quality
Act.

CONSOL
Energy
Inc.,
in
cooperation
with
the
U.
S.
Department
of
Energy's
National
Energy
Technology
lab
(
DOE
NETL),
the
Ohio
Coal
Development
Office
(
OCDO),
the
Illinois
Clean
Coal
Institute
(
ICCI),
and
the
Electric
Power
Research
Institute
(
EPRI),
has
conducted
an
extensive
test
program
to
measure
Hg
speciation
and
emissions
on
coal­
fired
boilers
with
wet
and
dry
Flue
Gas
Desulfurization
(
FGD)
with
and
without
Selective
Catalytic
Reduction
(
SCR)
equipment.
All
of
the
units
burned
bituminous
coal,
and
all
but
one
of
the
wet­
FGD
units
had
an
ESP
for
particulate
control.
Speciated
measurements
of
Hg
in
the
flue
gas
were
made
across
the
particulate
control
device
as
well
as
the
FGD,
and
in
the
case
of
SCR­
equipped
units,
ahead
of
the
SCR.
Appendix
A
provides
detail
on
each
unit,
including
the
type
of
FGD,
SCR
and
particulate
9­
127
collection
device,
and
citations
to
more
complete
reports
of
the
various
tests.
The
Ontario
Hydro
Method
(
OHM)
was
used
for
all
of
these
tests
with
the
exception
of
the
Hg
removal
across
the
ESP
which
was
based
on
the
Hg
content
of
the
ESP
fly
ash.

One
important
criterion
for
assessing
the
accuracy
of
Hg
emission
measurements
is
a
material
balance
(
notably
lacking
in
the
ICR
Part
III
data),
wherein
the
Hg
content
of
the
coal
is
measured
and
compared
against
the
sum
of
the
stack
Hg
emissions
and
the
Hg
contents
of
all
process
streams
that
contain
Hg
including
such
streams
as
the
bottom
ash,
ESP
ash,
FGD
solids,
and
mill
reject
pyrites.
All
of
the
data
contained
in
Appendix
A
and
summarized
below
have
a
material
balance
closure
of
±
120
percent
thus
assuring
a
high
degree
of
data
quality.

Table
1
below
lists
each
unit's
emission
control
devices,
the
Hg
removal
across
the
ESP,
the
total
(
coal­
to­
stack)
Hg
removal
and
the
average
Hg
removal
for
various
emissions
control
configurations.
9­
128
Table
1.
Mercury
Removal,
Various
Pollution
Control
Configurations
Bit
Coal
Plants
SCR
Part.
Control
Device
FGD
%
Hg
Removal
across
ESP
%
Hg
Removal
Coal­
to­
Stack
1
Yes
FF
Lime
Spray
Dryer
87.3
±
3.4
2
Yes
FF
Lime
Spray
Dryer
94.6
±
0.3
Average
percent
Hg
Removal
for
SCR/
FF/
FGD
91.06
±
5.2
5
Yes
ESP
Limestone,
in­
situ
Oxidation
17
85.8
±
2.8
6
Yes
ESP
Limestone,
in­
situ
Oxidation
24
88.2
±
4.2
7
Yes
ESP
Limestone,
in­
situ
Oxidation
6
83.6
±
2.7
8
Yes
ESP
Mg­
Lime,
ex­
situ
Oxidation*
71.6
±
5.2
9
Yes
ESP
Mg­
Lime,
Inhibited
Oxidation
86.7
±
2.8
10
Yes
ESP
Mg­
Lime,
Inhibited
Oxidation
89.2
±
3.6
11
Yes
Vent.
Scrub
Mg­
Lime
Vent.,
Scrub.
Inhib.
Oxidation
85.1
±
1.7
Average
percent
Hg
Removal
for
SCR/
CS­
ESP/
FGD
15.7
±
9.1
86.1
±
2.1
13
No
ESP
Limestone,
in­
situ
Oxidation
48.7
±
4.5
14
No
ESP
Limestone,
in­
situ
Oxidation
23
74.6
±
1.4
17
No
ESP
Mg­
Lime,
Nat.
Oxidation
24.0
±
11
66
±
3
18
No
ESP
Limestone,
in­
situ
Oxidation
7.0
±
2.0
56.0
±
6
19
No
ESP
Limestone,
Nat.
Oxidation
13.0
±
2.0
72
±
9
21
No
ESP
Limestone,
Nat.
Oxidation
9.0
±
1.0
67
±
3
22
No
ESP
Mg­
Lime,
Nat.
Oxidation
11.0
±
6.0
63
±
4
Average
%
Hg
Removal
for
CS­
ESP/
FGD
14.5
±
7.3
63.9
±
9.0
12
Yes
ESP
13
19.6
±
20.7
*
15
percent
of
flue
gas
is
bypassed
around
FGD.
Calculated
percent
Hg
removal
would
be
84
percent.

This
commenter
and
others
stated
that
EPA
must
consider
coal
and
process
variability
in
any
MACT,
cap
or
allowance
allocation
determination.
In
each
of
the
tests
shown
in
Table
1,
9­
129
four
OHM
tests
were
performed
over
a
two
to
three
day
period.
The
variability
evident
from
the
test
results
over
this
short
period
of
time
is
significant
and
must
be
considered
by
EPA.
The
standard
deviation
for
SCR/
FGD
equipped
units
is
2.1
percent,
indicating
a
relatively
small
variability
among
these
measurements.
The
Hg
removals
from
the
FGD­
only
units
have
a
standard
deviation
of
9.0
percent,
indicating
a
greater
variability
among
these
units.
Based
on
the
test
variability
shown
at
each
unit
and
the
variability
between
units,
the
commenter
believed
that
EPA
must
use
a
conservative
EMF
number
to
allow
for
the
margin
of
variability
inherent
in
both
the
Hg
measurements
and
the
performance
of
coal­
fired
units
due
to
coal
Hg
content
and
process
control.
Therefore,
the
commenter
recommended
that
EPA
use
EMF
values
reflecting
the
performance
at
the
lower
bound
of
a
confidence
interval
calculated
as
one
standard
deviation
about
the
average.
Table
2
below
compares
the
EMF's
calculated
in
this
manner
from
the
data
in
Table
1
above
to
the
EMF's
provided
by
EPA
in
Table
5
of
the
NODA.

Table
2.
EMF
Comparisons
Name
of
Control
EPA
2003
EMFs
CRA
2004
EMFs
EIA
AE02004
EMFs
CONSOL
Energy
EMFs
Bit
EMF
Bit
EMF
Bit
EMF
Bit
EMF
PC/
CS­
ESP
0.64
0.65
0.64
0.93
PC/
CS­
ESP/
FGD
0.34
0.40
0.34
0.45
PC/
CSESP
SCR/
FGD
0.10
0.15
0.10
0.16
PC/
FF/
SCR/
FGDDry
N/
A
N/
A
N/
A
0.14
PC/
SCR/
ESP
N/
A
N/
A
N/
A
0.80
The
commenter
believed
that
the
EMFs
for
the
wet
FGD
units
are
similar,
though
somewhat
greater
than
those
proposed
by
CRA.
One
notable
difference
is
the
EMF
for
CS­
ESPonly
units.
Because
of
the
interest
in
Hg
reduction
as
a
co­
benefit
of
NO
x
and
SO
x
controls,
there
has
been
relatively
little
done
to
characterize
emissions
from
this,
the
most
common
class
of
unit
in
use
now.
As
the
commenter
noted
in
their
June,
2004
comments
on
the
initial
proposal,
these
units
were
highly
under­
represented
in
the
ICR
Part
III
database.
The
commenter
believed
that
EPA
should
revise
the
estimated
EMF
for
these
units
to
0.93,
based
on
the
results
presented
here.

Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
first
phase
cap
is
based
on
EPA
modeling
of
the
Hg
co­
benefits
of
SO
2
and
NOx
controls
installed
for
compliance
with
the
CAIR
rulemaking.
See
final
rule
preamble
for
rationale
and
Chapter
7
of
final
CAMR
RIA
for
discussion
of
emissions
projections.
As
discussed
in
the
NODA,
for
the
final
rulemaking
analysis,
EPA
has
made
changes
to
some
of
its
co­
benefit
assumptions
for
subbituminous
units
with
SCR
and
FGD
9­
130
controls.
EPA
is
also
using
a
newer
version
of
EPA's
IPM
for
the
final
rulemaking.
Changes
to
the
modeling
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).

EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
Overall
the
1999
Hg
ICR
data
revealed
higher
levels
of
Hg
capture
for
bituminous
coal­
fired
plants
as
compared
to
subbituminous
and
lignite
coal­
fired
plants
and
a
significant
capture
of
ionic
Hg
in
wet­
FGD
scrubbers.
Additional
Hg
testing
indicates
that
for
bituminous
coals
SCR
has
the
ability
to
convert
elemental
Hg
to
ionic
Hg
and
thus
allow
easier
capture
in
a
wet­
FGD
scrubber.
This
understanding
of
Hg
capture
was
incorporated
into
EPA
modeling
assumptions
and
is
the
basis
for
our
projections
of
Hg
co­
benefits
from
installation
of
scrubbers
and
SCR
under
CAIR.
(
For
further
discussion
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005,
in
the
docket)

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
by
definition,
co­
benefit
reductions
occur
anyway
as
a
result
of
control
technologies
installed
to
meet
the
CAIR.
Hence,
it
is
unnecessary
to
establish
a
cap
to
achieve
Hg
reductions
through
co­
benefits.

As
the
commenter
noted
in
their
initial
comments,
because
co­
benefit
Hg
reductions
will
occur
anyway,
EPA's
better
course
is
to
measure
precisely
what
these
co­
benefits
are,
and
use
that
information
to
set
an
interim
cap
in
2012,
that
would
be
effective
in
2015.
Setting
the
initial
cap
in
2012
allows
EPA
to
quantify
the
precise
amount
of
co­
benefits
reductions,
and
also
allows
EPA
to
dispense
with
its
grossly
unfair
coal
rank
allowance
allocation
"
adjustment"
factors,
since
no
such
adjustments
would
be
needed
in
the
absence
of
an
initial
2010
cap.
As
well,
by
2012,
EPA
will
be
able
to
properly
assess
the
performance
of
new
Hg­
specific
control
reduction
technologies
such
as
ACI
to
reduce
Hg
emissions
across
all
coal
ranks.
The
commenter
was
confident
that
the
technology
will
show
that
roughly
equal
removal
levels
can
be
achieved
across
all
coal
ranks.
Hence,
EPA
would
not
be
justified
in
establishing
allowance
allocation
adjustment
factors
for
any
subsequent
cap.

The
commenter
noted
that
the
EEI's
modeled
"
Alternative
Hg
Trading"
scenario
outlined
in
the
NODA
generally
follows
this
approach
by
establishing
no
first
phase
co­
benefits
cap,
and
setting
an
initial
firm
cap
(
24
TPY)
in
2015.
Because
the
EEI
proposal
would
allow
banking
of
early
reduction
credits
above
co­
benefits,
the
eligibility
of
actions
that
qualify
for
early
reduction
credit
would
need
to
be
defined.
However,
this
early
reduction
and
banking
system
is
wholly
discretionary,
and
consequently
there
is
no
need
to
adjust
allocation
of
allowances
by
coal
rank
to
implement
it
since
there
is
no
specific
obligation
by
any
individual
source
to
reduce
Hg
emissions
to
a
pre­
determined
level.

Response:
9­
131
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
The
cap­
and­
trade
program
will
include
a
provision
for
banking.
See
final
rule
preamble
and
Chapter
5
comment
responses
for
further
discussion
of
banking.
EPA
is
not
including
a
provision
for
early
reduction
credits
in
the
final
rulemaking.
See
Chapter
5
response
to
comments
for
further
discussion
of
ERCs.

8.
More
recent
test
data
on
subbituminous
coal­
fired
units
equipped
with
SCR
indicate
that
SCR
does
not
enhance
the
oxidation
of
Hg0
on
such
coals
and,
thus,
does
not
provide
for
additional
capture
in
a
wet
scrubber
(
OAR­
2002­
0056­
1268,
­
1270).
Based
on
these
data,
EPA
is
considering
revising
the
emission
modification
factor
(
EMF)
for
subbituminous
coal­
fired
units
equipped
with
SCR
and
wet
FGD
in
the
IPM
model.
EPA
recommends
use
of
the
EMF
control
combination
before
an
SCR
is
added
(
i.
e.,
ascribe
no
additional
control
due
to
the
addition
of
the
SCF).
EPA
requests
comments
on
these
proposed
changes:
for
CS­
ESP/
SCR/
FGD,
use
CS­
ESP/
FGD
(
0.84);
for
FF/
SCR/
FGD,
use
FF/
FGD
(
0.27);
and
for
HSESP
SCR/
FGD,
use
HS­
ESP/
FGD
(
0.80).
EPA
also
requests
comment
on
the
appropriateness
of
using
other
test
data
(
DOE
and
EPRI
tests)
for
EMF
development
and
asks
commenters
to
submit
any
relevant
data.

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
mentioned
that
EPA
may
rely
on
information
gleaned
from
reports
that
were
not
available
for
public
review
prior
to
the
end
of
the
comment
period.
The
commenter
recommends
that
any
reports,
or
studies,
relied
upon
in
making
determinations
relevant
to
the
Hg
rule
be
made
available
for
public
review.

Response:
EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
This
testing
is
summarized
in
reports
by
EPA,
DOE
and
others
and
are
available
on
EPA's
website.
In
addition
a
comprehensive
summary
of
this
test
was
prepared
by
EPA's
Office
of
Research
and
Development
(
ORD)
assessment
and
made
available
in
the
docket
at
time
of
the
proposal.
available
in
For
the
final
rule
ORD
has
prepared
an
updated
assessment
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005,
in
the
docket).

Comment:

One
commenter
(
OAR­
2002­
0056­
5482)
stated
that
in
August
2003,
a
pilot­
scale
SCR
reactor
was
installed
at
a
Fort
Union
mine­
mouth
lignite­
fired
EGU
located
in
North
Dakota.
The
study
was
conducted
by
the
Energy
and
Environmental
Research
Center
(
EERC)
to
determine
the
ability
of
new
and
aged
catalyst
to
oxidize
Hg
at
full­
scale
EGUs.
The
results
indicate
that
SCR
technology
was
not
effective
in
oxidizing
Hg
and
that
the
sulfation
of
calcium
and
sodium
ash
9­
132
deposits
foul
the
catalyst
rendering
the
SCR
technology
ineffective
for
NO
x
control.

An
article
describing
the
findings
has
been
accepted
for
publication
in
Fuel
Processing
Technology.
A
copy
of
the
"
article
in
press"
entitled,
"
SCR
Catalyst
Performance
in
Flue
Gases
Derived
from
Subbituminous
and
Lignite
Coals"
can
be
downloaded
from
the
EERC
ftp
site:
ftp://
ftp.
undeerc.
orglbenson/
.

The
article
is
also
available
online
via
Science
Direct
in
the
"
Articles
in
Press"
section
for
the
following
title:
http://
authors.
elsevier.
com/
sd/
article/
S0378382004001870
.

Response:

EPA
has
examined
the
commenter's
analysis
in
context
of
the
final
rulemaking.
EPA's
modeling
Hg
co­
benefit
assumptions
already
assume
that
SCR
does
not
enhance
Hg
control
for
lignite
plants.

Comment:

One
commenter
(
OAR­
2002­
0056­
5482)
noted
that
Table
5
of
the
NODA,
"
Hg
Removal
Assumptions
for
Pollution
Control
Equipment,"
identifies
lignite
EMF
factors
for
various
EGU
pollution
control
configurations.
As
noted
in
the
above
EERC
study
and
EPA's
acknowledgment
of
a
lack
of
SCR
elemental
Hg
reduction
co­
benefits
for
subbituminous
coal
(
similar
to
Fort
Union
lignite),
the
this
commenter
recommends
an
EMF
factor
designation
of
1.0
or
"
NA"
(
not
applicable)
for
all
Fort
Union
EGU
pollution
control
configurations
employing
SCR.

As
previously
noted,
elemental
Hg
is
the
predominant
form
of
Fort
Union
Hg
emissions
and
conventional
air
pollution
control
equipment
provides
little
or
no
incidental
removal.
An
important
factor
impacting
EMF
values
is
the
high
variability
of
Hg
and
important
species
such
as
chloride
and
alkali.
The
interplay
of
the
chemical
factors
coupled
with
EGU
operation
variations
would
not
justify
an
EMF
factor
of
less
than
1.0.
The
EMF
factor
of
0.56
for
configuration
PC/
CS­
ESP/
FGD
is
not
representative
of
Fort
Union
lignite
EGU
emissions.

The
commenter
recommends
an
EMF
factor
of
1.0
be
employed
for
PC/
CS­
ESP/
FGD,
similar
to
the
PC/
CS­
ESP,
FF/
FGD­
Dry
and
PC/
FF
configurations.

No
Fort
Union
configurations
of
PC/
CS­
ESP/
FGD­
Dry
are
known.
The
commenter
recommends
an
EMF
factor
designation
of
"
NA."

The
commenter
also
recommends
an
EMF
factor
of
"
NA"
for
all
PC/
HS­
ESP
pollution
control
configurations
since
the
technology
is
not
applicable
or
utilized
by
Fort
Union
EGUs.

Response:

EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
9­
133
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
EPA
believes
the
lignite
factors
used
for
final
rulemaking
analysis
are
supported
by
ICR
test
data.
(
For
further
discussion
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005,
in
the
docket.)

Comment:

One
commenter
(
OAR­
2002­
0056­
5446)
stated
that
in
order
to
provide
a
level
playing
field
any
"
cap­
and­
trade"
type
regulatory
approach
must
include
appropriate
allocation
factors.
The
factors
currently
proposed
by
the
EPA,
1.0
for
bituminous,
1.25
for
subbituminous
and
3.0
for
lignite
do
not
adequately
address
this
issue.
Even
the
EPA
states
that
these
factors
are
only
"
directionally
correct,"
this
is
a
completely
inadequate
basis
for
setting
a
regulatory
standard.

Furthermore,
assessment
of
the
EMFs
used
in
the
different
models
indicates
that
these
allocation
factors
are
likely
to
be
inadequate.
For
the
most
common
generating
configuration
(
PC/
CS­
ESP
representing
approximately
59
percent
of
generating
capacity)
the
EPA
and
EIA
assume
a
36
percent
Hg
reduction
for
bituminous
coal
and
a
3
percent
reduction
for
subbituminous
coal,
CRA
assumes
a
35
percent
reduction
for
bituminous
coal
and
a
20
percent
reduction
for
sub­
bituminous
coal.
For
the
second
most
common
configuration
(
PC/
CS­
ESP/
FGD
representing
approx
16
percent
of
capacity)
the
EPA
and
EIA
assume
a
66
percent
Hg
reduction
for
bituminous
coal,
and
a
16
percent
and
27
percent
reduction
respectively
for
subbituminous
coal.
Even
when
adjusted
for
average
Hg
content
of
bituminous
and
subbituminous
coals
these
reduction
factors
imply
that
the
allocation
factor
for
subbituminous
coal
should
be
higher
that
the
1.25
proposed
by
the
EPA.

However
given
the
wide
range
of
uncertainty
in
the
reduction
factors
(
e.
g.,
a
reduction
factor
of
between
3
percent
and
20
percent
for
PC/
CS­
ESP
with
sub­
bituminous
coal)
basing
allocation
factors
on
the
relative
proportions
of
elemental
Hg
produced
by
the
different
coal
ranks
is
likely
to
be
a
more
robust
approach.

Because
the
amount
of
elemental
Hg
produced
effectively
reflects
the
difficulty
of
control,
factors
based
on
elemental
Hg
content
are
more
likely
to
result
in
an
even
distribution
of
the
compliance
burden
between
coal
ranks
in
the
long
term.
However,
because
plant
configuration
also
affects
Hg
capture
and
as
subbituminous
coal
is
typically
burned
in
plant
configurations
that
produce
little
co­
benefit
capture
(
e.
g.,
plants
with
dry
scrubbers)
a
subbituminous
factor
based
purely
on
elemental
Hg
content
will
be
inadequate
to
avoid
fuel
switching
in
the
short
term.
As
per
our
original
comments,
factors
of
1.0
for
bituminous,
1.9
for
subbituminous
and
2.95
for
lignite,
as
proposed
by
the
industry
majority
during
the
CAAAC
process,
appear
to
be
the
most
appropriate.
These
factors
have
been
calculated
from
the
floors
developed
by
industry
majority
position,
which
included
representatives
from
the
unions,
the
major
coal
producing
regions
and
a
large
proportion
of
the
electric
utility
industry.

Testing
to
date
indicates
that
the
presence
of
an
SCR
does
not
enhance
Hg
removal
from
sub­
bituminous
coals.
Therefore,
the
commenter
strongly
supports
the
EPA's
recommendation
9­
134
that
the
EMF
assume
that
the
presence
of
an
SCR
provides
no
additional
Hg
control
for
sub­
bituminous
coals.

Response:

As
discussed
in
the
Chapter
5,
section
5.6.1,
EPA
is
finalizing
coal
adjustment
factors
for
the
purpose
of
establishing
state
emission
budgets
of
1.0
for
bituminous
coals,
1.25
for
subbituminous
coals,
and
3.0
for
lignite
coals.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
stated
that
EPA
should
draw
upon
whatever
data
is
available,
provided
appropriate
data
quality
controls
have
been
applied.
In
this
regard,
however,
the
commenter
again
drew
attention
to
the
problems
with
EPA's
use
of
the
ICR
Part
III
data
set,
as
outlined
in
their
May
14,
2004
comments.
In
particular,
the
commenter
noted
their
concerns
associated
with
EPA's
use
of
short­
term
test
data.
Great
care
should
be
taken
to
account
for
the
uncertainty
and
variability
in
coal
quality,
unit
operation,
and
to
the
variable
performance
of
pollution
control
devices.
The
commenter
does
not
believe
that
the
large
degree
of
uncertainty
incorporated
by
these
variables
can
be
adequately
attenuated
through
short
term
tests
performed
on
a
limited
number
of
units,
coal
types,
plant
configurations
and
operating
conditions.
To
resolve
these
problems,
EPA
should
institute
a
comprehensive
test
program,
as
elsewhere
described
in
these
comments.

Response:

EPA
has
used
the
best
data
were
possible
in
developing
its
analysis
for
the
final
rulemaking.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter's
(
OAR­
2002­
0056­
5492)
question:
EPA
is
considering
making
three
changes
to
the
subbituminous
coal
EMF
used
in
the
IPM:
for
CS­
ESP/
SCR/
FGD
use
CS­
ESP/
FGD
(.
84);
for
FF/
CR/
FGD
use
FF/
FGD
(.
27);
and
for
HS­
ESP/
SCR/
FGD
use
HS­
ESP/
FGD
(.
8).
EPA
is
seeking
comments
on
these
proposed
changes.

In
the
NODA,
EPA
cites
two
literature
references:
OAR­
2002­
0056­
1268
and
OAR­
2002­
0056­
1270.
These
two
references
cite
the
same
source
data,
based
on
a
single
test.
The
two
reports
are
using
information
developed
and
reported
in
an
EPRI
report.
In
the
report,
EPRI
and
their
contractor
point
out
several
exceptions
to
standard
flue
gas
sampling
procedures.
First,
the
samples
are
single
point
and
are
not
a
full
or
even
a
partial
traverse
of
the
duct.
Flue
gas
9­
135
stratification
could
mean
that
the
observations
are
not
representative
of
the
entire
flue
gas
stream.
Second,
only
duplicate
flue
gas
Hg
samples
were
obtained.
In
all
EPA
methods,
samples
are
obtained
in
triplicate.
The
authors
state
that
".
.
.
the
data
set
presented
here
is
small,
so
the
reader
should
exercise
caution
in
extrapolating
the
results.
.
.
."

In
addition,
the
authors
state
that
"
an
increase
in
oxidized
Hg
from
8
percent
to
18
percent
(
occurred)
across
the
SCR."
They
go
on
further
to
state
"
Consequently,
Hg
capture
across
the
ESP
increased
from
60
percent
to
78
percent
as
a
result
of
SCR
operation."
The
authors
statements
in
the
cited
reports
do
not
support
EPA's
conclusion
that
"
SCR
does
not
enhance
the
oxidation
of
Hg."
The
commenter
respectfully
suggested
that
the
proposed
changes
are
unwarranted
based
on
the
data
submitted
by
EPA.

Question:
EPA
is
seeking
comment
on
the
appropriateness
of
using
other
test
data
for
EPM
development
and
requests
commenters
submit
any
test
data
that
may
be
relevant.

The
Department
of
Energy
has
operated
a
COHPAC
system
for
Hg
removal
at
the
Southern
Company
Gaston
Station
which
fired
a
low
sulfur
bituminous
coal
for
about
one
year.
At
an
injection
concentration
of
0.55
lb/
mmacf
and
using
2.7
denier
bags,
over
a
four­
month
period
the
average
Hg
removal
was
86
percent.
During
shorter­
term
tests
using
higher
denier
bags,
7
denier,
it
was
possible
to
achieve
greater
than
90
percent
Hg
removal.
The
weekly
average
Hg
removals
observed
at
the
Gaston
site
are
presented
in
e­
docket
text.

In
addition
to
the
COHPAC
tests,
additional
tests
were
conducted
using
activated
carbon
injection
on
CS­
ESP
and
SCR/
dry
FGD
units
firing
subbituminous
coals.
For
example,
at
the
subbituminous
coal
fired
Sunflower
Electrics
Holcomb
Station
which
is
equipped
with
a
SCR/
dry
FGD
system,
over
90
percent
Hg
reduction
was
achieved
for
the
entire
4­
week
test
period.

In
addition,
there
have
been
tests
at
Pleasant
Prairie
Station
that
fires
a
subbituminous
coal
and
is
equipped
with
a
CS­
ESP.
At
an
injection
rate
of
11
lb/
mmacf,
73
percent
Hg
removal
was
reported.

Additional
tests
were
completed
on
both
bituminous
and
subbituminous
coals.
There
are
a
number
of
publications
listed
at
the
following
web
address:
www.
adaes.
com
under
"
Publications"
on
the
tool
bar.
There
have
been
at
least
four
full­
scale
evaluations
of
ACI
on
PRB
coal
fired
units
(
Holcomb
Arapahoe
(
two
tests),
Meramec)
and
four
tests
on
lignite
fired
boilers(
Antelope
Valley,
Stanton
1,
M.
R.
Young,
and
Monticello).

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
9­
136
Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
co­
benefits
and
agreed
with
EPA's
proposal
to
assign
no
co­
benefit
to
the
addition
of
an
SCR
at
a
site
with
an
SO
2
control
that
is
burning
a
western
fuel.
This
is
generally
supported
by
the
small,
but
growing,
body
of
data
available
to
date.
These
data
are
provided
in
the
detailed
comments,
as
are
suggested
EMFs
for
a
number
of
fuel/
air
pollution
control
configurations.

Power
plants
firing
a
bituminous
coal
can
expect
to
experience
oxidized
Hg
fractions
in
the
flue
gas
entering
the
FGD
that
range
from
75­
90
percent
 
i.
e.,
high
but
not
necessarily
always
in
the
90
percent
range.
There
does
not
appear
to
be
a
significant
increase
in
Hg
oxidation
for
PRB
coals,
and
potential
low­
chloride
bituminous
coals.

Response:

EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
EPA
believes
the
factors
used
for
final
rulemaking
analysis
are
supported
by
test
data.
EPA's
Hg
co­
benefit
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
said
that
in
conducting
the
various
modeling
exercises,
different
stakeholders
used
different
emission
modification
factors
(
EMF)
to
calculate
the
Hg
co­
control
benefits
of
different
NO
x
and
SO
2
controls.
The
EPA
requests
comments
on
what
EMF
are
appropriate.
As
shown
in
Table
5
of
the
NODA,
there
are
differences
in
EMF
the
agency
has
developed
and
those
used
by
Charles
River
Associates
(
CRA)
for
industry
stakeholder
modeling.
The
commenter
noted
that
the
EMF
used
by
CRA
are
consistently
lower
than
the
EMF
developed
by
EPA,
that
is,
they
result
in
less
co­
control
of
Hg
emissions
than
assumed
by
EPA.
The
result,
not
surprisingly,
is
that
industry
stakeholders
estimate
that
Hg
emissions
will
be
higher
after
implementation
of
CAIR
requirements
than
EPA
has
stated.
Because
EPA
has
proposed
to
establish
the
first
phase
of
its
pollution
trading
scheme
to
reflect
reductions
achieved
as
a
co­
benefit
of
CAIR,
the
effect
of
industry's
suggested
EMF
changes
would
be
to
inflate
the
initial
Hg
cap,
making
it
easier
to
meet
without
significant
control,
or
making
it
easier
for
companies
to
bank
allowances
for
future
use.

With
the
exception
of
new
data
on
the
effects
of
SCR
on
Hg
oxidation
when
subbituminous
coals
are
fired,
the
commenter
saw
no
new
information
in
the
other
commenter's
remarks
that
should
lead
EPA
to
change
the
EMF
in
the
IPM.
EPA
developed
the
existing
EMF
after
analyzing
the
extensive
ICR
data
set.
In
contrast,
there
are
no
new
analyses
of
Hg
9­
137
co­
control
presented
by
other
commenters.
Thus,
EPA
need
not
revise
its
EMF,
despite
the
desire
of
industry
stakeholders
to
raise
the
first
phase
Hg
cap.
With
respect
to
EPA's
intention
to
revise
the
EMF
associated
with
the
use
of
SCR
with
subbituminous
coals,
the
agency
does
not
provide
sufficient
information
for
us
to
comment
on
whether
this
is
a
legitimate
action.
The
agency
merely
refers
to
"
more
recent
test
data."
EPA
must
submit
to
the
docket
all
of
the
test
data
along
with
the
agency's
analysis
of
such
test
data
in
support
of
any
such
changes
to
the
EMF.
Revising
the
EMF
associated
with
the
use
of
SCR
with
subbituminous
coals
without
making
such
data
and
analysis
publicly
available
would
be
arbitrary.

Fourth,
EPA
also
mentions
Hg
speciation
in
the
context
of
conducting
economic
modeling
with
the
IPM.
With
respect
to
the
use
of
different
speciation
profiles
in
the
IPM,
EPA
notes
that
the
national
estimate
of
emissions
of
the
three
forms
of
Hg
is
Hg0
 
54
percent,
Hg+
2
 
43
percent,
and
Hgp
 
3
percent.
The
agency
states
that
plant­
specific
estimates
based
on
these
data
were
used
in
the
IPM
modeling
activities.
The
IPM
should
not
be
revised
with
respect
to
Hg
speciation.
To
the
extent
that
different
speciation
profiles
have
been
estimated
for
different
coal
types
and
control
device
configurations,
these
data
have
already
been
incorporated
into
the
IPM
through
the
use
of
EMF.
The
EMF
are
average
control
levels
that
are
calculated
from
average
Hg
and
chlorine
levels
in
coal
and
averages
of
test
data,
so
the
use
of
average
speciation
profiles
in
the
IPM
model
is
appropriate.
The
commenter
noted
however,
that
EPA
could
and
should
improve
the
speciation
profiles
used
in
deposition
modeling,
as
discussed
above.

Response:

EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
This
testing
is
summarized
in
reports
by
EPA,
DOE
and
others
and
are
available
on
EPA's
website.
In
addition
a
comprehensive
summary
of
this
test
was
prepared
by
EPA's
Office
of
Research
and
Development
(
ORD)
assessment
and
made
available
in
the
docket
at
time
of
the
proposal.
For
the
final
rule
ORD
has
prepared
an
updated
assessment
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005,
in
the
docket).
With
regard
to
speciated
profiles,
IPM
modeling
includes
only
total
Hg
emissions
projections
as
output.
EPA
than
post­
processes
IPM
unit
level
results
to
determine
the
speciated
form
of
Hg
at
the
unit
level.
This
information
is
than
used
in
deposition
modeling.
The
determination
on
speciated
emissions
is
based
on
1999
ICR
data.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
noted
that
EPA
was
considering
revising
the
EMFs
for
subbituminous
coal­
fired
units
equipped
with
SCR
and
wet
FGD.
After
reviewing
the
literature
cited
by
EPA
to
support
this
change
and
discussing
the
supporting
data
with
EPA
R&
D
and
EPRI,
the
commenter
did
not
believe
that
the
available
data
support
the
proposed
changes.
First,
there
are
not
two
independent
literature
sources
as
cited
by
EPA
in
the
NODA.
These
two
papers
simply
report
the
same
information
from
a
single
set
of
measurements
on
a
PRB
coal­
fired
unit,
equipped
with
an
SCR,
a
CS­
ESP,
originally
reported
in
EPRI
Report
1005400
dated
9­
138
December
2002.
Notably,
although
EPA
proposes
to
use
these
data
to
modify
the
EMFs
for
FGD­
equipped
units,
the
one
test
cited
in
these
two
reports
was
done
on
a
unit
with
no
FGD.
It
also
is
noteworthy
that
the
report
states,
"
Caution
is
urged
in
drawing
conclusions
from
this
limited
set
of
data.
The
results
are
based
on
short­
term
tests
that
might
be
misleading
due
to
the
potential
for
substantial
variation
in
total
and
speciated
mercury
concentration."
Moreover,
the
results
do
show
a
significant
increase
in
oxidized
Hg
across
the
SCR
(
from
8
percent
to
18
percent),
and
a
total
Hg
removal
(
78
percent)
for
a
SCR­
CESP
unit.
The
commenter
believed
that
the
proper
manner
to
evaluate
the
effect
of
SCR
operations
is
the
impact
on
total
Hg
removal.
These
results,
the
only
ones
that
EPA
cites,
indicate
that
a
boiler
equipped
with
an
SCR­
CS
ESP
combination
firing
a
subbituminous
coal
can
achieve
a
78
percent
Hg
reduction.
One
of
the
cited
references
states
"
Consequently,
mercury
capture
across
the
ESP
increased
from
60
percent
to
78
percent
as
a
result
of
SCR
operation."
The
EPA,
DOE,
and
EPRI
authors
ascribe
a
significant
increase
in
Hg
removal
to
the
SCR
operation.
The
cited
literature
does
not
support
EPA's
contention
that
they
should
"...
ascribe
no
additional
control
due
to
the
addition
of
the
SCR..."
Rather
the
cited
papers
state
that
the
operation
of
the
SCR
improved
total
Hg
capture.

The
commenter
added
that
in
addition
to
the
papers
cited
by
EPA
in
the
NODA,
there
was
a
joint
study
conducted
by
EPA
R&
D
and
EPRI
at
the
Texas
Genco
WA
Parish
Station.
(
The
final
report
is
in
draft.)
The
Parish
Station
burns
subbituminous
coal
and
is
equipped
with
an
SCR/
FF/
wet
FGD
air
pollution
control
system.
This
system
achieved
64
percent
Hg
control
with
the
FF/
wet
FGD
in
operation.
With
the
SCR/
FF/
wet­
FF/
wet­
FGD
in
operation,
the
Hg
removal
increased
to
79
percent.
Again
the
operation
of
the
SCR
significantly
increased
the
co­
benefit
Hg
removal
of
the
air
pollution
control
system.

In
the
commenter's
opinion
the
literature
provided
no
supporting
information
for
the
proposed
changes
to
the
EMFs.
Instead,
it
indicates
that
the
EMF
for
subbituminous
coal­
fired
units
equipped
with
CS­
ESP/
SCR/
FGD
should
be
0.2,
and
for
units
equipped
with
SCR/
FF/
FGD
should
be
between
0.2
and
0.3.

Response:

EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
EPA
has
assumed
for
the
final
rulemaking
analysis
that
for
subbituninous­
fired
units
that
SCR
has
the
no
ability
to
convert
elemental
Hg
to
ionic
Hg
and
thus
allow
easier
capture
in
a
wet­
FGD
scrubber.
EPA
is
thus
using
the
emission
modification
factors
for
CS­
ESP/
SCR/
FGD,
use
CS­
ESP/
FGD
(
0.84);
for
FF/
SCR/
FGD,
use
FF/
FGD
(
0.27);
and
for
HS­
ESP/
SCR/
FGD,
use
HS­
ESP/
FGD
(
0.80).
EPA
EPA's
Hg
co­
benefit
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
9­
139
Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
the
different
levels
of
Hg
co­
benefits
predicted
from
implementation
of
the
CAIR
rule
are
hardly
surprising.
The
1999
Information
Collection
Request
(
ICR)
stack
testing
results,
which
serve
as
the
basis
for
most
emission
modification
factors,
showed
highly
variable
Hg
removals
in
plants
equipped
with
the
same
control
equipment.
In
addition,
predicting
the
level
of
Hg
co­
benefits
resulting
from
the
CAIR
rule
requires
one
to
estimate
the
effects
of
SCRs
on
Hg
removal.
Mercury
testing
of
SCRs
is
limited
and
questions
remain
about
a
number
of
factors
that
may
affect
the
amount
of
elemental
Hg
that
is
converted
to
ionic
Hg
in
an
SCR.
As
a
result
of
these
uncertainties,
it
is
impossible
to
predict
the
true
co­
benefits
that
will
be
achieved
from
implementation
of
the
CAIR
rule.
As
was
described
in
the
preceding
response,
the
commenter
believed
that
instead
of
trying
to
set
a
"
hard"
cap
based
on
co­
benefits
in
2010.
EPA
would
be
better
served
by
imposing
a
"
soft"
cap
and
commencing
trading
in
2015.

The
commenter
agreed
with
the
Electric
Power
Research
Institute
(
EPRI)
that
many
of
the
EMFs
should
be
revised,
in
most
cases
very
slightly,
to
reflect
additional
information
that
has
been
received
since
EPA
last
ran
its
IPM
model.
For
example,
for
bituminous
coals,
the
commenter
recommended
these
changes:

°
CS­
ESP/
wet
FGD:
Revise
EPA's
EMF
from
0.34
to
0.40
because
six
additional
test
results
have
doubled
the
database.

°
SCR/
CS­
ESP/
wet
FGD:
Revise
EPA's
EMF
from
0.10
to
0.15
based
upon
ICR
measurements
and
recent
SCR/
FGD
co­
benefits
tests.

For
other
configurations
(
e.
g.,
SCR/
FF/
wet
FGD
and
SCR/
FF/
dry
FGD)
the
commenter
believed
that
no
change
is
justified.
A
complete
list
of
our
recommendations
is
attached.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
is
establishing
a
phase
I
cap
of
38
tons
in
2010
and
phase
II
cap
of
15
tons
in
2018.
See
final
rule
preamble
for
rationale.
EPA
projections
of
Hg
co­
benefits
are
based
on
1999
Hg
ICR
emission
test
data
and
other
more
recent
testing
conducted
by
EPA,
DOE,
and
industry
participants.
EPA
EPA's
Hg
co­
benefit
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:
9­
140
One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
they
believed
that
there
were
inadequate
data
to
assign
any
measurable
or
reproducible
level
of
SCR
co­
benefits
for
either
wet
or
dry
scrubbers.
Two
independent
sources
of
data
support
this
conclusion.

First,
EPRI
has
synthesized
the
increase
in
oxidized
Hg
across
SCR
equipment
at
18
sites.
Of
the
18
sites,
three
fire
Powder
River
Basin
("
PRB")
coal
and
exhibit
an
increase
in
oxidized
Hg
between
effectively
zero
(
Site
S9)
to
19
percent
(
Site
1).
These
data
suggest
there
is
effectively
no
Hg
oxidation
across
the
SCR
catalyst.
The
commenter
did
not
think
that
the
anomalous
Site
1
unit
 
a
cyclone
boiler
 
is
representative
of
the
boiler
design
and
characteristics
of
the
boiler
population
in
this
nation.
That
boiler
has
relatively
low
particulate
matter
loading,
elevated
NO
x
level
entering
the
SCR
reactor,
and
the
lowest
space
velocity
(
e.
g.,
most
generous
catalyst
volume)
of
any
of
the
tested
units.
Cyclone
boilers
comprise
less
than
5
percent
of
the
boiler
population.
The
other
units
are
representative
of
boiler
design
and
catalyst
space
velocity.
While
they
suggest
a
3­
4
percent
increase
in
Hg
oxidation
with
PRB
coal,
this
is
within
the
"
noise"
of
the
measurement
systems.

The
second
set
of
data
that
supports
this
conclusion
is
the
measurement
of
increased
Hg
removal
across
a
wet
scrubber
due
to
SCR.
Of
the
sites
reported,
only
Site
11
is
equipped
with
wet
scrubber.
The
use
of
SCR
induces
an
11
percent
increase
in
the
removal
of
Hg
by
a
wet
scrubber.
Site
11
is
equipped
with
a
fabric
filter
that
precedes
the
wet
scrubber,
and
EPRI
reports
that
much
of
the
Hg
oxidation
occurs
across
the
fabric
filter,
unrelated
to
the
SCR.
Consequently,
it
appears
that
much
of
the
11
percent
increase
in
Hg
removal
is
due
to
the
fabric
filter,
and
not
the
SCR.

For
these
reasons,
and
because
the
data
are
sparse
and
preliminary,
the
commenter
suggested
that
zero
co­
benefits
be
assigned
to
the
role
of
SCR
on
PRB
and
other
subbituminous
coals.

Response:

EPA
has
assumed
for
the
final
rulemaking
analysis
that
for
subbituninous­
fired
units
that
SCR
has
the
no
ability
to
convert
elemental
Hg
to
ionic
Hg
and
thus
allow
easier
capture
in
a
wet­
FGD
scrubber.
EPA
EPA's
Hg
co­
benefit
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).

Comment:

One
commenter
(
OAR­
2002­
0056­
5411)
stated
that
their
results
indicated
that
the
EMFs
are
not
related
to
coal
rank,
but
do
vary
with
coal
age.
The
consistent
relationship
between
the
EMFs
and
the
geologic
age
of
coal,
coupled
with
simple
criteria
that
definitively
establish
the
age
of
coal,
provide
a
scientifically
justified
and
practical
basis
to
subcategorize
coal
for
regulation
of
Hg
emissions.

The
commenter
stated
that
commercial
U.
S.
coal
was
formed
during
two,
substantially
9­
141
different
geologic
ages,
and
can
be
broadly
grouped
as
older
Paleozoic
coal,
and
younger
Mesozoic/
Cenozoic
coal.
The
mutually
exclusive
geographic
occurrence
of
Paleozoic
coal
and
Mesozoic/
Cenozoic
coal
is
significant.
Unlike
coal
rank,
which
varies
locally,
with
ASTM
standard
vintage,
and
with
assay
precision,
geologic
age
can
be
unambiguously
determined
based
on
coal
origin
location.
Moreover,
the
origin
location
of
coal
shipments
to
units

50
MW
is
publicly
reported;
if
regulation
of
units
as
small
as
25
MW
is
required,
determining
the
coal
origin
location
is
clearly
less
burdensome
than
representative
sampling
for
coal
rank
assays.
Finally,
a
precise
coal
origin
location
is
not
required
to
establish
geologic
age.
Indeed,
the
"
state­
of­
origin"
reported
on
FERC
form
423
is
sufficient
to
establish
geologic
age
for
current
coal
production.

The
commenter
also
stated
that
in
the
unlikely
event
that
the
age
of
a
coal
shipment
is
disputed,
the
200
million
year
interval
between
Paleozoic
coal
and
Mesozoic/
Cenozoic
coal
is
significant.
Ubiquitous
pollen
from
angiosperms
(
flowering
plants),
as
well
as
certain
terpene
resins,
are
found
in
Cretaceous
and
Paleogene
coal,
but
absent
from
Paleozoic
coal.
Consequently,
if
shipment
receipts
or
transportation
records
prove
insufficient,
palynological
or
geochemical
assays
can
definitively
settle
such
disputes.

The
commenter
calculated
Emission
Modification
Factors
(
EMFs)
for
five
of
the
12
emission
control
technologies
listed
in
Table
5
of
the
December
1,
2005
Federal
Register
Notice
(
69
FR
p.
69871).
Their
calculation
method
is
described
in
their
docket
comment
(
Appendix
B)
together
with
the
tabulated
data
used
for
this
calculation.
The
results
are
illustrated
in
the
figure
below,
which
shows
greater
Hg
capture
for
units
burning
Paleozoic
coal
than
for
units
burning
Mesozoic/
Cenozoic
coal.
Note
that
all
U.
S.
Paleozoic
age
coal
is
bituminous
or
anthracite
rank,
whereas
the
rank
of
U.
S.
Mesozoic/
Cenozoic
age
coal
varies.
Importantly,
the
figure
below
also
shows
that
the
EMF
does
not
vary
with
coal
rank,
but
does
vary
with
coal
age.

The
commenter
added
that
the
EMFs
that
they
calculated
are
not
directly
comparable
to
those
shown
in
Table
5
of
the
NODA.
Nonetheless,
with
two
minor
exceptions,
our
EMFs
are
generally
closest
to
the
CRA
2004
values
listed
in
the
table.
The
first
exception
is
for
the
relatively
small
HS­
ESP/
FGD
technology
class,
where
our
EMF
values
are
more
similar
to
the
EPA
and
EIA
values.
Secondly,
our
EMFs
for
the
important
CS­
ESP/
FGD
technology
class
suggest
slightly
less
Hg
capture
for
this
class
than
any
of
corresponding
EMFs
in
the
table.

U.
S.
Cenozoic/
Mesozoic
age
coal
has
greater
fractional
mercury
emissions
(
EMF
values)
than
U.
S.
Paleozoic
age
coal,
when
burned
in
units
equipped
with
conventional
emission
control
technologies;
this
difference
is
not
related
to
coal
rank.
9­
142
Notes,
PC:
pulverized
coal;
HS­
ESP:
hot­
side
electrostatic
precipitator;
CS­
ESP:
cold
side
electrostatic
precipitator;
HS­
ESP­
FGD:
hot­
side
electrostatic
precipitator
with
wet
Flue
Gas
Desulphurization;
FF­
FGD­
Dry:
Fabric
Filter
and
spray
dry
adsorption
Flue
Gas
Desulphurization.

More
than
25,800
ICR
records
were
used
to
calculate
the
EMF
values
presented
in
the
figure
above;
~
5,500
ICR
coal
assay
data
records
where
the
location
origin
was
not
reported
were
ignored,
as
were
~
3,300
records
corresponding
to
blended
coals.
The
tonnage
weighted
EMFs
calculated
for
this
comment
(
Table
3)
indicate
the
fractional
emissions
expected
if
all
U.
S.
coal
were
burned
in
each
technology
class,
rather
than
the
coals
that
are
currently
burned.
Although
this
approach
is
neutral
with
respect
to
fuel
switching,
it
may
overestimate
Hg
emissions
for
some
units
that
burn
blended
coal.
The
omission
of
blended
coals
is
likely
to
have
slightly
decreased
our
EMF's
for
CESP/
FGD
units
and
PC/
FF­
FGD­
Dry
units.
This
effect
can
be
demonstrated
for
these
technologies
using
the
equations
listed
in
Table
Bl
(
see
OAR­
2002­
0056­
5411),
which
predict
net
improved
Hg
capture
for
blends
containing
both
high
and
low
chlorine
coal.
The
equations
show
predicted
Hg
capture
substantially
increases
as
chlorine
content
approaches
500
ppm,
but
only
modestly
rises
above
1000
ppm
chlorine.
Thus,
blending
to
optimum
chlorine
content
between
500
and
1000
ppm,
should
result
in
a
net
reduction
of
Hg
emissions.

A
potentially
more
significant
limitation
of
the
EMFs
presented
in
this
comment
is
equally
applicable
to
those
listed
in
Table
5
of
the
NODA.
Current
FF/
FGD­
Dry
technology
is
limited
to
low­
sulfur
coal.
Fortunately,
excluding
the
~
30
percent
of
U.
S.
coal
production
that
contains
more
than
1
lb
sulfur/
106
Btu,
does
not
significantly
change
the
our
calculated
EMFs
for
9­
143
FF­
FGD­
Dry
technology;
respective
EMFs
for
Paleozoic
and
Mesozoic/
Cenozoic
coal
are
0.13
and
0.64,
for
low­
sulfur
coal
burned
in
units
with
FF/
FGD­
Dry
technology.
However,
assuming
a
1
lb
sulfur
/
106
Btu
limit,
FF/
FGD­
Dry
technology
is
only
applicable
to
~
25
percent
of
northern
lignite,
and
hardly
any
Texas
lignite,
or
coal
from
Ohio
and
Northern
Pennsylvania
­
all
of
these
areas
produce
relatively
high
Hg
coal.
Consequently,
one
of
the
best
existing
Hg
reduction
technologies
is
not
appropriate
for
many
coals
with
the
highest
Hg
contents.

Due
to
time
constraints,
the
commenter
noted
without
comment
the
remarkably
improved
Hg
capture
suggested
by
the
EMFs
listed
in
Table
5
for
units
with
SCR
technology
compared
to
those
without
SCR.
For
the
same
reason,
the
commenter
had
not
considered
Indonesian,
Venezuelan,
Columbian,
Polish,
or
Alaskan
coal,
although
these
calculations
are
comparatively
straightforward.
Evaluation
of
potential
coal
supplies
from
countries
not
included
in
the
ICR
is
more
problematic;
assay
data
from
the
USGS
international
coal
data
base
might
be
useful
for
this
purpose.

Response:

For
the
final
rulemaking,
EPA
is
using
Hg
emission
modification
factors
based
on
coal
rank.
We
believe
this
approach
is
consistent
with
our
understanding
of
Hg
control.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).
EPA
EPA's
Hg
co­
benefit
assumptions
can
found
in
the
IPM
documentation
in
the
rulemaking
docket
(
see
Documentation
Summary
for
EPA
Base
Case
2004
(
v.
2.1.9)
Using
the
Integrated
Planning
Model,
EPA,
October
2004).

B.
Issues
of
Hg
Speciation
General
Comments
Concerning
Issues
of
Mercury
Speciation
Comment:

One
commenter
(
OAR­
2002­
0056­
5460)
stated
that
the
NODA
reveals
an
undue
concern
for
alleged
uncertainties
concerning
Hg
speciation
and
the
relative
contribution
of
domestic
power
plants
to
global
Hg
emissions.
The
commenter
further
stated
that
EPA
need
not
and
should
not
delay
regulation
of
domestic
power
plant
Hg
emissions
until
those
alleged
uncertainties
are
resolved.
According
to
the
commenter,
rather,
to
the
extent
uncertainties
exist
concerning
such
topics
as
Hg
speciation,
transport,
deposition
and
exposure,
those
uncertainties
provide
a
basis
for
imposing
stricter
protections
so
as
to
ensure
an
adequate
margin
of
safety.
The
commenter
stated
that
no
other
approach
is
consistent
with
the
preventive
and
precautionary
purposes
of
the
CAA.

The
commenter
(
OAR­
2002­
0056­
5460)
also
stated
that
developing
a
Hg
speciation
profile
is
not
relevant
to
setting
a
proper
MACT
floor
pursuant
to
CAA
section
112.
The
commenter
added
that,
rather,
by
statute
that
floor
is
to
be
based
on
the
average
of
actual
9­
144
emissions
achieved
by
the
top
12
percent
of
the
coal­
fired
power
plants
for
which
EPA
has
data.
The
commenter
added
that,
equally
important,
developing
a
speciation
profile
will
not
cure
the
legal
defects
in
EPA's
proposed
section
111
approach.

The
commenter
stated
that
a
speciation
profile
might
be
relevant
to
certain
aspects
of
the
beyond­
the­
floor
analysis
required
by
section
112,
but
EPA
cannot
and
should
not
use
either
the
fact
of
speciation,
or
uncertainty
about
the
nature
of
such
speciation,
as
a
basis
for
concluding
that
section
112
no
longer
applies.
The
commenter
further
stated
that,
indeed,
EPA's
December
2000
determination
that
it
was
necessary
and
appropriate
to
regulate
Hg
emissions
from
power
plants
was
not
limited
to
particular
species
of
Hg,
and
no
basis
exists
for
EPA
to
revisit
or
revise
that
determination
now.

Response:

EPA
is
not
delaying
regulation
of
U.
S.
utility
units
until
all
uncertainties
are
resolved.
However,
we
believe
that
these
uncertainties
do
factor
into
the
approach
that
should
be
taken
in
such
regulation.
We
believe
that
the
cap­
and­
trade
approach
being
finalized
adequately
accounts
for
the
uncertainties.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
stated
that
the
Agency's
interest
in
speciation
profiles
and
how
they
relate
to
Hg
control,
fate
and
transport,
and
ultimately
human
exposure
raises
the
question
of
whether
the
Agency
is
contemplating
basing
emission
rates
or
trading
schemes
on
the
level
of
different
Hg
species
emitted.
The
overall
impression
left
by
this
line
of
inquiry
is
that
the
Agency
is
suggesting
that
only
oxidized
Hg
emissions
from
power
plant
need
to
be
controlled.
This
is
clearly
inappropriate
and
arbitrary
 
elemental
Hg
is
no
less
important
than
oxidized
Hg
in
terms
of
the
environmental
and
public
health
impacts
in
the
U.
S.
To
imply
that
elemental
Hg
does
not
contribute
to
Hg
exposure
in
the
U.
S.
is
incorrect,
because
elemental
Hg
is
eventually
oxidized
and
deposited.
This
deposition
can
occur
on
the
east
coast
of
the
U.
S.
as
a
result
of
emissions
from
a
boiler
located
in
the
western
U.
S.,
or
it
may
occur
in
the
western
U.
S.
from
elemental
Hg
emissions
circling
the
globe.
Comments
submitted
to
the
EPA
by
a
consortium
of
scientists
convened
by
the
Hubbard
Brook
Research
Foundation
(
HBRF)
emphasize
that
elemental
Hg
can
be
rapidly
converted
to
oxidized
Hg
and
deposited
locally
or
regionally.
This
process
is
known
to
occur
after
polar
sunrises
in
the
Arctic
and
Antarctic
atmosphere
and
in
the
marine
boundary
layer
in
the
presence
of
marine
aerosols.
Furthermore,
emissions
of
oxidants
from
utilities
and
other
high­
temperature
sources
provide
ample
reactants
for
oxidizing
elemental
Hg.
New
research
shows
that
dry
deposition
of
elemental
Hg,
uptake
of
elemental
Hg
by
the
forest
canopy
and
subsequent
litter
fall
can
provide
more
than
twice
as
much
Hg
to
a
watershed
than
wet
deposition.
Moreover
elemental
Hg
can
be
converted
to
reactive
gaseous
Hg
(
RGM
or
oxidized
Hg)
at
a
tree's
leaf
surface,
thereby
enhancing
the
deposition
of
elemental
Hg
at
the
local
and
regional
scale
and
reducing
long
range
transport.
Consequently,
there
is
ample
evidence
that
emissions
of
elemental
Hg
must
be
reduced
in
conjunction
with
oxidized
Hg
emissions.
9­
145
In
addition,
EPA
cannot
even
entertain
the
notion
that
elemental
Hg
emissions
need
not
be
controlled
from
U.
S.
power
plants
and
maintain
an
ounce
of
credibility
in
global
Hg
protocol
discussions.
One
of
Administrator
Leavitt's
"
guiding
principles"
recognizes
that
Hg
is
a
global
issue
and
asks
what
opportunities
there
are
to
reduce
Hg
emissions
worldwide.
The
opportunities
to
reduce
global
emissions
(
and
their
subsequent
impacts
in
the
U.
S.)
will
only
arise
if
the
U.
S.
is
serious
about
reducing
total
Hg
emissions
from
coal­
fired
power
plants.

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
noted
that
the
NODA
includes
a
discussion
about
speciation.
It
is
unclear
to
them
what
EPA
means
by
this
discussion.
If
EPA's
intention
is
to
regulate
by
species,
it
is
important
to
note
that
the
workgroup
discussed
that
idea
briefly
and
rejected
it
as
an
unworkable
solution.
Further,
although
some
companies
have
indicated
that
Hg
emitted
as
oxidized
all
becomes
elemental
Hg
in
the
plume
as
it
exits
the
stack,
this
is
counter
to
the
vast
research
on
Hg's
behavior
in
the
atmosphere.
The
key
point
here
is
that
this
industry
finding
is
too
preliminary,
is
within
the
error
of
measurements,
and
has
had
inconsistent
results
in
different
power
plant
plumes.
Even
if
this
one
reaction
among
many
is
confirmed
in
later
studies,
this
work
needs
to
be
interpreted
in
the
context
of
many
other
atmospheric
reactions
of
Hg
whose
net
effect
and
direction
tendency
is
just
the
opposite:
conversion
of
elemental
Hg
into
oxidized
Hg.
Oxidized
Hg
deposits
locally
and
regionally,
and
a
MACT
that
requires
ALL
power
plants
to
substantially
reduce
emissions
significantly
(
80­
90
percent)
would
protect
against
hot
spots.

The
discussion
about
speciation
relates
to
the
atmospheric
fate
and
transport
of
Hg
emissions.
Regardless
of
where
emissions
originate,
in
a
world
where
international
transport
is
becoming
an
increasing
public
health
concern,
there
is
no
justification
for
this
country
turning
its
back
on
our
contributions
to
transboundary
pollution.
This
commenter
believed
the
U.
S.
should
show
leadership
by
controlling
Hg
emitted
here,
regardless
of
where
and
how
emissions
travel.

Response:

EPA
is
showing
leadership
through
issuance
of
this
first­
ever
regulation
limiting
Hg
emissions
from
coal­
fired
power
plants.
We
agree
that,
at
this
time,
it
is
inappropriate
to
regulate
Hg
emissions
by
species
and,
therefore,
have
structured
the
final
rule
on
a
total
Hg
basis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5559)
stated
that
the
1999
ICR
data
is
the
most
comprehensive
body
of
Hg
speciation
data
available
that
was
developed
through
consistent
and
standard
measurement
methods.
The
commenter
stated
that
EPA
should
rely
on
the
ICR
data
as
the
primary
basis
for
evaluating
existing
Hg
control
measures.
The
additional
body
of
Hg
emission
testing
conducted
since
1999
by
researchers
and
industry
can
be
used
to
augment
the
ICR
data
but
in
doing
so
EPA
needs
to
account
for
differences
in
testing
methods
and
conditions.
9­
146
Response:

EPA
concurs
with
the
commenter.

Comment:

One
commenter
(
OAR­
2002­
0056­
5474)
stated
that
it
fully
supports
using
different
multipliers
for
the
different
coal
ranks
for
the
reasons
stated
above,
but
is
concerned
that
the
multiplier
will
be
determined
by
using
the
coal
or
coals
that
a
unit
burned
in
1999
rather
than
the
coal
a
unit
is
actually
burning
at
the
time
the
rules
are
finalized.
That
approach
is
inequitable
and
grossly
unfair
to
any
unit
that
has
switched
from
a
higher
to
lower
rank
coal
since
1999.
This
commenter
has
two
units
that
made
the
decision
in
2001
to
switch
from
bituminous
to
subbituminous
coal,
to
reduce
NOx
emissions
to
comply
with
new
anticipated
regulatory
requirements.
The
engineering
and
design
work
needed
to
make
the
equipment
and
operational
changes
necessary
for
such
a
switch
was
started
in
late
2001.
Construction
commenced
in
early
2002
and
was
completed
in
2003.
After
several
test
burns
in
2003,
subbituminous
coal
became
the
sole
fuel
source
at
the
beginning
of
2004.
The
commenter
has
no
plans
to
switch
back
to
bituminous
coal
in
the
future
at
such
units.
In
fact,
such
an
occurrence
would
be
extremely
unlikely,
since
the
move
was
made
to
meet
more
stringent
permanent
NOx
requirements
for
these
units.
Using
EPA's
methodology,
the
baseline
heat
input
for
these
units
will
be
multiplied
by
1.0
when
computing
the
number
of
allowances
to
be
allocated
to
such
units
either
for
the
State
trading
program
budget
or
for
a
Federal
trading
program
administered
by
EPA.
However,
as
these
units
will
be
combusting
subbituminous
coal
when
the
Hg
reduction
requirements
become
effective,
such
units
will
be
unfairly
penalized,
since
they
will
not
be
allocated
allowances
based
on
the
coal
actually
being
burned,
which
will
result
in
approximately
25
percent
fewer
allowances
for
each
unit.
EPA
should
not
punish
units
that
switched
fuels
to
comply
with
earlier
environmental
requirements
not
related
to
the
CAMR,
by
allocating
allowances
based
on
the
fuel
type
burned
in
an
arbitrary
baseline
year,
1999,
rather
than
the
fuel
being
burned
at
the
time
when
the
rules
are
actually
finalized.

Moreover,
there
may
be
Utility
Units
that
have
done
the
opposite
of
this
commenter
(
i.
e.,
that
have
instead
switched
to
a
higher
rank
coal
since
1999).
If
EPA
were
to
use
1999
as
the
determining
year
for
these
units,
their
owners
would
receive
a
windfall
of
allowances,
because
the
proposed
methodology
would
base
the
allowance
allocation
on
a
coal
type
that
is
in
fact
no
longer
being
burned.

To
remedy
this,
this
commenter
suggests
the
following
approach.
EPA
should
use
as
the
determinate
for
which
coal
rank
multiplier
to
apply,
the
rank
of
coal
that
was
combusted
by
such
unit
in
the
year
the
CAMR
rule
is
finalized.
Ideally,
the
goal
should
be
to
award
allowances
based
on
the
rank
of
coal
that
a
unit
is
actually
burning.
Alternatively,
EPA
should
specifically
allow
for
units
like
the
commenter's
that
switched
fuels
to
a
lower
coal
rank
to
petition
EPA
and,
if
States
are
actually
allocating
allowances
to
Hg
budget
units,
the
relevant
State,
to
receive
an
adjustment
to
the
coal
rank
factor
in
recognition
of
any
situation
like
the
one
described
above
that
would
allocate
Hg
allowances
in
an
inequitable
manner
to
units
that
switched
fuels.
9­
147
Response:

EPA
is
using
1999
coal
type
as
the
basis
for
the
adjustment
of
the
baseline
for
establishing
plant
mercury
allocations
to
be
used
in
developing
the
state
and
tribal
emission
budgets
for
the
final
rulemaking.
However,
in
the
example
allocation
methodology
for
states
to
allocate
at
the
unit
level
EPA
is
finalizing
a
different
approach.
EPA's
example
allows
states
to
use
baseline
heat
input
for
the
years
2000
through
2004
and
coal
type
for
those
years.
Under
the
model
trading
rule,
EPA
notes
that
States
and
Tribes
have
the
authority
to
allocate
at
the
unit
level
as
they
choose.
See
Chapter
5
and
final
rule
preamble
for
further
discussion
of
emission
budgets
and
allocation
methodology.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
stated
that
EPA
should
adjust
the
Hg
allowance
allocations,
by
coal
rank,
to
reflect
the
disparity
of
Hg
removal
efficiencies
that
NOx
and
SO2
controls
have
among
coal
ranks
in
any
emissions
trading
program
established
under
sections
111
or
112.
This
commenter,
and
others,
agreed
with
EPA's
proposal
that
coal
rank
emission
control
disparities
justify
using
differing
allowance
allocation
adjustments
for
each
coal
rank.
However,
the
commenter
argued
that
the
allowance
allocation
adjustment
factor
for
subbituminous
coals
should
be
increased
from
the
proposaled
factor
of
1.25
to
a
higher
factor
of
1.5.

Response:

EPA
is
finalizing
coal
adjustment
factors
for
the
purpose
of
establishing
state
emission
budgets
of
1.0
for
bituminous
coals,
1.25
for
subbituminous
coals,
and
3.0
for
lignite
coals.
These
adjustment
factors
are
considered
to
be
appropriate
numbers
based
on
the
test
data
currently
available.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5548)
suggested
that
it
should
be
obvious
that
EPA's
allowance
allocation
approach,
and
the
similar
approaches
advocated
by
Southern,
UARG,
and
others,
based
on
speciation
and
control
issues,
are
fundamentally
flawed.
The
primary
question
has
been
articulated
by
WEST
Associates'
comment
that
"
for
facilities
that
would
have
to
purchase
allowances,
WEST
Associates
recommends
that
an
additional
allocation
adjustment
factor
be
applied
that
promotes
equitable
allowance
distribution,
particularly
in
Phase
I
of
the
cap"
program
reasoning
that
"
it
is
critical
that
the
allocations
of
mercury
allowances
reflect
the
relative
level
of
mercury
control
for
bituminous,
subbituminous
and
lignite
coal
ranks
that
will
be
achieved,
within
each
coal
rank,
by
the
SO2
and
NOx
controls
required
under
the
CAIR
by
2010."
That
this
comment,
and
similar
comments
by
Southern,
UARG,
and
the
SEC
that
EPA
has
cited
in
the
NODA,
is
a
misconception
seems
clear.
There
is
absolutely
no
reason
to
adjust
allowance
allocations
for
purchasers
of
allowances
based
on
relative
levels
of
Hg
reduction
capability
among
9­
148
coal
ranks
because
purchasers
of
allowances
are
not
reducing
anything;
they
are
simply
buying
allowances
representing
reductions
made
by
others.
That
is
the
very
point
of
the
entire
cobenefits
cap­
and­
trade
approach,
where
allowance
purchases,
and
not
controls,
are
the
means
to
compliance
for
many
sources.
It
is
equally
obvious
that
allowance
purchasers
do
not
pay
different
prices
depending
upon
the
rank
of
coal
they
burn.
A
purchaser
of
Hg
allowances
has
the
same
equitable
status
regardless
of
the
rank
of
coal
burned.
The
only
relevant
consideration
at
issue
is
the
price
at
which
these
three
classes
of
allowance
purchasers
(
bituminous,
subbituminous,
and
lignite)
must
buy
allowances.
And
that
price
is
exactly
the
same
between
all
of
the
coal
ranks.

Response:

EPA
is
finalizing
coal
adjustment
factors
for
the
purpose
of
establishing
state
emission
budgets
of
1.0
for
bituminous
coals,
1.25
for
subbituminous
coals,
and
3.0
for
lignite
coals.
These
adjustment
factors
are
considered
to
be
appropriate
numbers
based
on
the
test
data
currently
available.
For
further
discussion
see
final
rule
preamble
(
section
IV.
C.
4)
and
Technical
Support
Document
for
the
Clean
Air
Mercury
Rule
Notice
of
Final
Rulemaking,
State
and
Indian
Country
Emissions
Budgets,
EPA,
March
2005.

Comment:

One
commenter
(
OAR­
2002­
0056­
5332)
stated
that
the
modeling
results
reported
in
the
NODA
do
not
fill
the
gap.
Because
the
modeling
was
done
by
numerous
stakeholders
with
different
objectives,
crucial
assumptions
(
e.
g.,
demand
growth;
natural
gas
prices;
availability,
performance,
and
cost
of
control
technologies)
vary,
with
no
attempt
at
systematic
inquiry.
Moreover,
the
results
are
not
presented
in
uniform
metrics
and,
therefore,
in
many
cases
are
not
comparable.
The
commenter
urged
the
Agency
to
undertake
a
systematic,
transparent
modeling
effort,
along
the
lines
that
the
Clean
Energy
Group
and
other
stakeholders
have
recommended.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Analyses
in
support
of
the
process
will
be
presented
in
the
final
CAMR
Regulatory
Impact
Analysis
document.

1.
EPA
received
numerous
comments
on
subcategorization
by
coal
type
and
the
speciation
profiles
resulting
from
the
combustion
of
various
types
of
coal.
EPA
sought
additional
specific
data
and
information
on
the
speciation
profiles
of
various
types
and
blends
of
coal.

Comment:

One
commenter
(
OAR­
2002­
0056­
5484)
provided
detailed
information
and
a
technical
report
with
its
comments
(
OAR­
2002­
0056­
2948)
of
June
29,2004,
on
the
speciation
of
Hg
in
coal­
fired
power
plant
plumes.
In
the
NODA,
EPA
has
asked
for
more
information
on
Hg
9­
149
speciation
and
has
also
indicated
that
it
is
performing
a
benefits
analysis
that
attempts
to
estimate
the
reduction
in
adverse
human
health
effects
that
will
occur
as
a
result
of
reducing
Hg
emissions
from
coal­
fired
power
plants.
To
this
end,
this
commenter
wishes
to
provide
more
information
to
supplement
the
information
provided
in
June
and
to
re­
state
the
implications
of
this
information.
OAR­
2002­
0056­
5484
is
the
latest
summary
of
the
research
which
has
shown
that
the
fraction
of
Hg
emitted
as
oxidized
Hg
from
coal­
fired
power
plants
is
rapidly
converted
to
elemental
Hg.
Current
models
do
not
account
for
this
conversion.
Research
is
underway
by
EPRI
and
others
to
better
understand
the
chemical
mechanisms
that
explain
this
observation
and
to
incorporate
the
mechanisms
into
air
quality
models.
The
most
important
implication
of
this
research
finding
is
that,
because
the
observed
transformations
are
not
taken
into
account
in
current
assessments,
current
estimates
of
the
benefits
from
reducing
power
plant
Hg
are
overestimated.
This
overstatement
applies
to
the
results
of
the
most
comprehensive
assessment
conducted
to
date
 
that
conducted
by
EPRI
 
which
already
shows
that
very
small
Hg
deposition
and
exposure
reductions
will
result
from
either
the
cap­
and­
trade
or
MACT
approaches.
EPA
should
include
these
transformations
in
whatever
benefits
estimation
it
conducts.

Comment:

One
commenter
(
OAR­
2002­
0056­
5556)
referred
to
the
speciation
of
Hg
and
noted
that
new
information
challenged
the
estimated
lifetime
of
elemental
Hg
before
it
is
deposited.
Also,
new
data
are
demonstrating
the
oxidation
of
elemental
Hg
to
reactive
gaseous
Hg
during
periods
of
enhanced
photochemical
activity
with
high
ozone
and
warm
temperatures
(
OAR­
2002­
0056­
5557).

Response:

EPA
has
addressed
the
commenter's
issue
through
the
application
of
the
Community
Multiscale
Air
Quality
(
CMAQ)
modeling
system
in
estimating
current
and
future
levels
of
total
mercury
deposition
for
the
purposes
of
this
rule.
This
sophisticated
photochemical
air
quality
model
is
able
to
differentiate
across
Hg
emissions
species
and
account
for
the
complex
atmospheric
reactions
as
referenced
by
this
commenter.
The
model
and
these
specific
reactions
are
detailed
in
the
Air
Quality
Modeling
TSD
(
docket
#
OAR­
2002­
0056­
6130).

Comment:

One
commenter
(
OAR­
2002­
0056­
5564)
noted
that
the
principal
business
of
San
Miguel
Electric
Cooperative,
Inc.,
is
the
production
of
electric
energy
in
South
Central
Texas.
Production
includes
one
coal­
fired
power
plant
and
one
lignite
mine.
The
lignite
mine
supplies
fuel
only
for
the
San
Miguel
Generating
Station
and
produces,
on
average,
3.3
million
tons
of
lignite/
year.
The
one
generating
unit
fires
only
lignite
provided
by
this
mine
and
comprises
100
percent
of
San
Miguel's
generating
capacity;
average
yearly
output
is
3.2
million
MWh.

The
commenter
provided
comments
on
the
issues
of
Hg
speciation.
The
commenter's
unit
has
an
ESP
and
a
wet
FGD
system
for
controlling
PM
and
SO2
and
has
performed
two
stack
tests
9­
150
for
Hg.
These
tests
were
conducted
in
2002
and
2004
using
appropriate
methods
and
the
test
results
were
provided
in
the
comments.

Response:

EPA
appreciates
the
submission
of
the
data.

Comment:

The
commenter
(
OAR­
2002­
0056­
5490)
stated
that
their
comments
are
all
related
to
the
second
section,
"
Electric
Utility
Sector
Modeling
and
Hg
Speciation,"
especially
as
it
relates
to
Gulf
Coast
lignite.
The
commenter
continued
its
research
into
the
Hg
content
of
the
coals
it
combusts,
the
speciation
of
the
Hg
in
the
flue
gases
prior
to
existing
control
devices,
the
removal
efficiencies
of
the
existing
control
devices
and
the
Hg
emissions
(
and
speciation)
from
its
stacks.
Unfortunately,
the
reports
for
the
testing
had
not
been
finalized
at
this
time.
The
commenter
also
participated
in
four
DOE
Hg
control
technology
projects.
The
results
of
Hg
analysis
on
samples
of
coal
taken
through
October
31,
2004,
from
pulverizer
feeders
at
the
commenter's
nine
coalfired
units
were
provided
in
the
comments.
All
of
these
units,
except
Sandow
Unit
4,
burned
blends
of
Gulf
Coast
lignite
and
western
subbituminous
coal.
The
minimum
Hg­
in­
coal
values
are
from
high
percentage
subbituminous
samples
and
the
maximum
values
are
from
high
percentage
lignite
samples.
Sandow
Unit
4
burned
Gulf
Coast
lignite
only.

The
Cl
in
the
Gulf
Coast
lignite
ranged
from
less
than
1
part
per
million
(
ppm)
to
170
ppm,
which
is
less
than
the
1999
ICR
Part
II
analysis
indicated.
Chlorine
content
affected
the
speciation
of
Hg
generated
from
firing
coal.

Response:

EPA
appreciates
the
submission
of
the
data.

Comment:

Two
commenters
(
OAR­
2002­
0056­
5456,
­
5505)
mentioned
that
EPA
is
seeking
input
on
issues
of
Hg
speciation.
The
NODA
states,
"
During
this
data
collection
effort,
incoming
coal
shipments
for
all
coal­
fired
power
plants
in
the
U.
S.
were
tested
for
Hg
content
(
for
calendar
year
1999)."
Perhaps
the
more
fundamental
issue
than
the
speciation
of
the
Hg
is
one
of
if
the
Hg
content
of
the
coal
is
accurate
in
the
EPA
ICR
database.
There
has
been
much
controversy
expressed
that
the
proposed
MACT
Hg
emission
standards
for
subbituminous
coal
are
too
high
creating
a
"
compliance
coal"
for
Hg,
particularly
for
PRB
coal.
This
conclusion
was
based
upon
an
analysis
of
the
EPA
coal
Hg
content
database.

Since
that
time,
there
has
been
some
testing
of
advanced
Hg
control
technologies
with
various
types
of
coals
and
control
configurations.
Also
included
in
these
analyses
were
a
quantification
of
the
coal
Hg
content,
and
inlet
total
vapor
(
Hg).
9­
151
The
commenter
was
a
participant
in
the
testing
done
at
Sunflower
Electric's
Holcomb
Station,
located
near
Garden
City,
Kansas.
The
plant
burns
Wyoming
PRB
coal,
and
has
a
SDA/
FF
control
configuration,
which
is
widely
considered
to
be
a
"
typical"
configuration
for
future
coal­
fired
plants;
particularly
those
that
consume
PRB
coal.
Mercury
reduction
testing
took
place
at
this
plant,
funded
by
the
DOE
and
others.
The
results
of
the
test
are
presented
figures
1
and
2
of
OAR­
2002­
0056­
5456
,
and
show
that
in
this
test
PRB
coal
significantly
exceeds
EPA's
proposed
MACT
Hg
emission
limit
of
5.8
lb
Hg/
TBtu
for
subbituminous
coal.

Comment:

Commenter
OAR­
2002­
0056­
5505
provided
information
from
Arapahoe
Unit
3,
a
44
MWe
PRB
coal­
fired
unit
in
the
Denver
metro
area.
The
unit
is
equipped
with
a
reverse
air
fabric
filter
and
a
dry
sodium
injection
system
for
SO2
removal.
Testing
at
this
plant
occurred
over
a
two­
week
period
in
May
2004
to
evaluate
the
use
of
Amended
Silicates
for
Hg
removal.
The
interesting
part
of
the
work
from
the
perspective
of
the
commenter
is
that
it
included
two
separate
PRB
coals.
These
coals
were
burned
separately,
and
were
not
mixed
during
the
test.
One
of
the
coals
had
significantly
higher
Hg
content
that
the
other
coal.

The
commenter
provided
results
for
the
higher
Hg­
content
coal
tests.
In
both
tests,
PRB
Coal
A
yielded
significantly
higher
results
than
EPA's
proposed
MACT
emission
limit
of
5.8
lb
Hg/
TBtu.
From
the
final
report,
PRB
Coal
A
"
had
nearly
twice
the
Hg
of
[
PRB
Coal
B]
with
a
Hg
content
of
0.071
ppm
(
as­
received
basis).
[
PRB
Coal
A]
yielded
flue
gas
vapor­
phase
Hg
concentrations
in
the
range
of
12
to
16

g/
Nm3.
For
Xcel's
samples
from
[
PRB
Coal
A]
shipments
to
Arapahoe,
their
average
Hg
content
has
been
measured
as
0.06
ppm,
somewhat
lower
than
the
value
for
the
[
PRB
Coal
A]
sample
obtained
during
the
May
trial."

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
Hg
speciation.
Test
results
obtained
by
the
commenter
in
the
last
year
have
not
markedly
changed
the
speciation
correlations
developed
from
the
ICR.
While
coal
Cl
content
appears
to
drive
the
degree
of
flue
gas
Hg
oxidation,
other
factors
may
also
have
a
noticeable
effect
on
this
process;
tests
and
chemical
modeling
studies
are
seeking
to
quantify
the
role
and
significance
of
these
other
factors.
Speciation
continues
to
be
viewed
as
important
for
determining
the
most
applicable
and
cost­
effective
controls,
the
achievable
emission
levels,
and,
to
a
certain
extent,
the
potential
impact
of
emissions
from
a
given
plant
on
Hg
deposition
onto
downwind
water
bodies.

Response:
9­
152
EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
subsequent
to
the
ICR
stack
sampling
in
1999,
Hg
speciation
measurements
have
been
taken
as
part
of
research
studies
sponsored
by
DOE,
EPRI
and
others.
These
studies
have
explored,
among
other
things,
the
effect
of
SCR
on
Hg
oxidation
and
Hg
removal
using
ACI.
In
addition,
a
number
of
coal­
fired
power
plants
have
conducted
their
own
sampling
of
Hg
emissions
to
determine
the
levels
and
species
of
Hg
that
are
emitted.

In
general,
this
additional
testing
has
produced
results
that
continue
to
show
Hg
emission
variability
like
that
seen
during
the
ICR
stack
testing.
As
EPRI's
NODA
comments
indicate
(
see
OAR­
2002­
0056­
5469),
these
recent
Hg
results
do
not
substantially
change
the
Hg
speciation
correlations
that
EPRI
produced
using
the
ICR
data.

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5494)
noted
that
the
NODA
solicits
input
on,
among
other
matters,
issues
related
to
"
Hg
speciation"
and
the
results
of
four
approaches
of
modeling
Hg
emissions
under
various
emission
control
equipment
deployment
scenarios.
All
those
model
calculations
start
with
certain
assumptions
about
the
relative
proportions
of
the
chemical
composition
of
Hg
emissions
exiting
the
stacks
(
three
species
 
elemental,
ionized,
and
particle­
bound)
from
coals
classified
as
bituminous,
subbituminous,
and
lignite.

This
commenter
addresses
two
issues
relating
to
coal
ranks/
Hg
speciation:
(
1)
uncertainty
associated
with
compliance
with
the
proposed
regulations
for
coal
used
at
several
Southwestern
power
plants,
and
(
2)
questions
associated
with
the
appropriateness
of
developing
the
proposed
Hg
rule
utilizing
the
ICR
III
database's
Hg
emissions
data
segregated
under
the
three
coal
rank
classifications.
Specifically,
these
comments
address
unique
problems
in
applying
the
ASTM
methodology
referenced
in
the
proposed
rule
to
determine
coal
ranks
and
compliance
obligations.

EPA's
proposed
rule
refers
to
the
ASTM
coal
ranking
methodology
and
sets
different
Hg
emission
limitations
for
different
coal
ranks.
However,
the
ASTM
coal
ranking
methodology
may
not
be
appropriate
for
regulating
Hg
emissions
from
certain
coal­
fired
power
plants.
The
9­
153
ASTM
methodology
is
based
on
analyses
on
a
"
moist"
basis,
or
the
moisture
content
of
the
coal
in
the
mine.
ASTM
D388­
99
clearly
requires
that
coal
rank
should
be
determined
while
the
coal
is
in
the
mine.
Coal
ranking
classification
made
any
other
way,
such
as
under
"
as
received"
is
designated
by
ASTM
D388­
99
as
"
apparent
rank."

The
EPA's
ICR
data
collection
efforts
discuss
reporting
coal
properties
on
an
"
as
received"
basis
at
each
respective
coal
fired
power
plant.
In
some
cases,
as
discussed
below,
coal
determined
to
be
subbituminous
in
the
mine
according
to
the
ASTM
methodology
could
very
well
transform
to
bituminous
when
it
is
"
received"
at
the
plants,
stored
on
site,
or
while
combusted
in
a
boiler,
because
its
"
inherent
moisture"
value
could
change.

Moreover,
in
the
case
of
coals
whose
heating
value
falls
in
the
overlapping
region
between
10,500
to
11,500
Btu/
lb,
only
an
agglomeration
test
can
definitively
determine
its
actual
coal
rank
(
D388­
99).
The
proposed
rule
does
not
contemplate
situations
like
those
identified
here
and
raises
considerable
ambiguity
as
to
the
applicable
regulatory
requirements.
This
situation
is
very
different
from
the
"
coal
blending"
scenario
addressed
in
the
proposed
rule
to
establish
the
appropriate
emission
limit.
This
commenter
believes
that
the
rule
should
be
made
very
clear
as
to
what
the
operator's
regulatory
obligations
are.
Specifically,
the
commenter
requests
that
EPA
expressly
state
in
the
rule
where
the
coal
rank
should
be
determined:
at
the
mine,
"
as
received"
at
the
plant,
or
when
the
coal
is
combusted
in
the
boiler.

EPA
developed
the
rule,
as
noted
above,
by
segregating
Hg
emissions
test
data
(
ICR
III)
from
81
units
by
the
rank
of
the
coal
used
during
the
emission
tests.
In
this
process,
coal
data
were
taken
from
the
ICR
III
test
reports,
and
constituted
coal
characteristics
on
an
"
as
received"
basis.
Data
for
one
of
the
four
units
used
in
calculating
the
MACT
level
for
subbituminous
coal
came
from
the
commenter's
Cholla
Power
Plant
(
Cholla
Unit
3),
and
in
1999
Cholla
reported
the
coal
used
during
the
ICR
III
tests
to
be
"
Bituminous/
Subbituminous."
Recently,
Cholla
has
reviewed
coal
data
submitted
to
the
EPA
under
ICR
III
and
ICR
II
throughout
1999,
and
concluded
that
Cholla
burned
bituminous
coal
most
of
the
time.
In
fact,
that
review
has
also
concluded
that
Cholla
Unit
3
burned
bibuminous
coal
during
the
ICR
III
testing.
Based
on
these
conclusions,
the
commenter
believes
that
EPA
segregated
ICR
III
data
from
Cholla
Unit
3
in
the
incorrect
subbituminous
category.

The
commenter's
review
of
the
ICR
III
data
for
the
other
three
top
performing
units
(
used
to
calculate
the
subbituminous
MACT
level)
suggests
that
at
least
two
of
those
units'
coal
ranks
may
have
been
incorrectly
classified
.
Thus,
if
the
coal
ranks
have
indeed
been
misclassified
before
calculating
the
MACT
levels
for
the
subbituminous
coal
category,
the
coal
rank­
based
determination
of
Hg
emission
limitations
may
be
in
error.

The
commenter
understands
that
similar
concerns
were
included
in
the
comments
submitted
to
the
EPA
in
the
proposed
rulemaking
by
the
Subbituminous
Energy
Coalition
(
SEC).
Therefore,
the
commenter
respectfully
requests
that
EPA
reassess
the
classification
of
ICR
III
Hg
emissions
test
data
by
coal
rank
and
the
subsequent
statistical
analyses
done
in
developing
the
proposed
MACT
levels/
national
Hg
emissions
cap
and
trade
program
(
and
its
allowance
allocations).
9­
154
Commenter
OAR­
2002­
0056­
5494
agreed
that
EPA
has
found
that
the
Cl
content
of
coal
determines
the
relative
proportions
of
various
chemical
species
of
Hg
emitted.
For
example,
combusting
Eastern
bituminous
coal
(
with
its
high
Cl
content)
creates
higher
proportions
of
ionized
and
particle­
bound
Hg,
while
Western
subbituminous,
Western
bituminous,
and
lignite
coals
(
all
with
much
lower
Cl
content)
create
a
higher
proportion
of
elemental
Hg.
EPA
has
also
found
that
ionized
and
particle­
bound
Hg
emissions
are
more
efficiently
controlled
in
existing
pollution
control
devices
(
such
as
SO2
scrubbers
and
PM
control
devices).
Therefore,
modeling
results
of
Hg
emissions
from
stacks
depend
on
the
assumed
relative
proportions
of
the
three
Hg
species.

The
commenter
believed
that
regulating
Hg
emissions
on
the
ASTM
methodology
of
coal
ranking
(
based
primarily
on
heating
value)
may
not
be
appropriate,
at
least
where
the
Btu
value
for
bituminous
and
subbituminous
coal
overlaps
(
as
noted
by
ASTM
D388­
99).
EPA's
proposed
rule
sets
MACT
levels
based
on
coal
ranks:
for
example,
the
proposed
emissions
limits
are
2.0
lb/
TBtu
for
bituminous
and
5.81
lb/
Btu
for
subbituminous
coals.
There
are
several
plants
in
the
Western
and
Southwestern
U.
S.
that
utilize
coal
whose
rank
can
vary
between
bituminous
and
subbituminous
from
time
to
time,
even
for
coal
coming
from
the
same
seam.
Given
below
are
two
different
types
of
examples
where
the
commenter
believes
such
changes
can
occur.

First,
the
commenter
considered
the
case
of
coal
whose
heating
value
falls
in
the
"
overlapping
region"
between
bituminous
and
subbituminous
coals.
Several
Western
power
plants
are
"
mine­
mouth"
plants,
and
hence,
restricted
to
utilize
coal
burned
in
the
adjacent
mine.
One
such
plant,
the
commenter's
Four
Corners
Power
Plant,
uses
coal
from
the
Navajo
Mine
on
the
Navajo
Reservation
in
Northwestern
New
Mexico.
Navajo
Mine's
coal
has
fairly
low
heating
value
(
typically
under
9,000
Btu,
on
an
"
as
received
basis")
and
very
high
ash
content
(
typically
20­
25
percent).
Over
the
past
decades,
the
mine
operator
assured
the
commenter
that
its
coal
was
subbituminous
coal.

If
the
ASTM
methodology
is
utilized,
the
Navajo
Mine's
coal's
"
mineral­
free"
heating
value
often
falls
in
the
10,500
to
11,500
Btu
range,
the
overlap
region
between
bituminous
and
subbituminous
coal
classification.
Under
such
conditions,
ASTM
methodology
requires
an
"
agglomeration
test"
to
determine
the
coal
rank.
Very
limited
agglomeration
tests
conducted
by
the
commenter
indicate
that
the
Navajo
Mine's
coal
could
be
bituminous,
contrary
to
long­
held
belief
and
assurances
from
the
coal
supplier.
EPA's
proposed
rule
(
69
FR
4665)
emphasizes
the
significance
of
coal
rank
in
the
engineering
design
of
power
plants
and
their
operation.
Therefore,
Four
Corners,
and
several
other
plants
in
the
Southwest
designed
to
burn
subbituminous
coal,
may
be
forced
to
comply
with
the
Hg
emission
limitation
applicable
to
bituminous
coal.

The
commenter
reported
that
its
experience
with
coal
from
the
McKinley
Mine
in
New
Mexico
used
at
the
Cholla
Plant
provides
a
situation
completely
different
from
the
above
example.
There,
the
"
apparent
rank"
on
occasion
falls
in
the
range
of
11,300
to
11,800
Btu/
lb
range.
If
the
"
Free
Swelling
Index"
is
applied
to
that
coal,
that
coal
is
non­
agglomerating,
and
thus,
will
be
classified
as
subbituminous.
Under
those
circumstances,
coal
from
the
McKinley
Mine
could
vary
from
bituminous
to
subbituminous
on
a
daily
basis.
9­
155
The
commenter
reported
that
EPA
staff
said
that
they
never
envisioned
that
plants
would
undertake
"
agglomeration
tests"
on
a
routine
basis,
as
it
is
time­
consuming
and
expensive.
This
situation
leads
to
two
potential
problems.
First,
the
commenter
notes
that
there
is
considerable
uncertainty
concerning
the
plant's
compliance
obligations
under
both
MACT
and
cap­
and­
trade
regulatory
approaches
(
i.
e.,
via
calculation
of
the
national
cap
as
well
as
the
Hg
allowance
allocations).
Second,
the
commenter
notes
that
in
situations
like
the
one
described
above,
it
may
be
possible
to
"
blend
coals"
in
such
way
to
bring
its
heating
value
to
just
below
the
threshold
level
to
classify
it
as
subbituminous.
Such
a
situation
can
create
opportunities
for
"
gaming"
the
regulatory
system.
These
potential
scenarios
are
untenable
and
should
be
clearly
addressed
in
the
final
rule.

The
commenter
related
the
second
issue
to
variability
in
moisture
content,
which
can
change
during
the
mining
process,
transportation
to
the
power
plant,
and
combustion
in
a
boiler.
For
example,
the
Cholla
Power
Plant
(
as
well
as
certain
other
power
plants
in
the
Southwest)
utilizes
coal
from
several
mines,
including
the
McKinley
Mine
in
New
Mexico.
Typically,
McKinley
Mine
adds
about
3
to
4
percent
moisture
in
dust
suppression
activities.
Adding
moisture
reduces
its
heating
value,
and
according
to
the
ASTM
methodology
coal
rank
is
determined
on
a
moist,
mineral
free
basis
for
subbituminous
coals.
At
the
plant,
storage
of
coal
in
the
open
(
prior
to
combustion)
and
pulverization
can
result
in
loss
of
some
moisture.

The
commenter
reported
that
when
EPA
assembled
the
ICR
II
and
III
database,
no
guidance
was
given
to
plant
operators
about
any
adherence
to
ASTM
methodology
in
developing
the
data
and
reporting
it
to
EPA.
Accordingly,
plant
operators
relied
on
the
information
on
coal
ranks
provided
by
the
coal
suppliers,
and
reported
the
same
data
to
the
ICR
database.
It
appears
that
EPA
developed
the
coal
rank­
based
Hg
rule,
and
the
ASTM
methodology
was
brought
in
later
as
an
afterthought.
Upon
careful
review
of
the
ASTM
methodology,
the
commenter
believes
that
potential
problems
like
the
ones
discussed
above
exist.
If
EPA
retains
the
coal
rank­
based
Hg
regulatory
scheme,
then
the
commenter
recommends
that
the
rule
should
clarify
that
the
coal
rank
reported
by
the
coal
supplier
(
mine)
will
be
the
basis
of
determining
the
appropriate
Hg
emission
limitation.
This
commenter
believes
that
forcing
the
plants
to
conduct
agglomeration
tests
on
a
routine
basis
is
unreasonable
and
will
create
uncertainty
in
plants'
compliance
obligations.

Because
Cholla
Unit
3
was
one
the
four
"
top
performing"
units
used
to
calculate
the
MACT
level
for
the
subbituminous
coal
category,
the
commenter
recently
reviewed
the
coal
data
reported
in
1999.
The
commenter
found
that
the
coal
rank
data
was
reported
as
"
Bituminous/
Subbituminous"
during
the
ICR
III
tests.
After
the
proposed
rule
was
published
with
its
reference
to
ASTM
methodology,
the
commenter
recently
calculated
the
Btu
value
of
the
coal
on
a
moist,
mineral­
free
basis,
utilizing
the
coal
analysis
data
reported
in
Cholla's
ICR
III
test
report.
These
calculations,
as
per
ASTM
methodology,
lead
us
to
conclude
that
Cholla
Unit
3
indeed
burned
bituminous
coal
during
the
ICR
III
testing.
Accordingly,
the
commenter
believed
that
ICR
III
test
data
from
Cholla
Unit
3
were
inappropriately
classified
under
the
subbituminous
coal
category,
and
consequently,
use
of
data
from
that
unit
to
calculate
the
subbituminous
MACT
level
may
be
in
error.
9­
156
The
commenter
had
also
evaluated
the
coal
ranks
reported
for
some
of
the
units
that
were
tested
under
ICR
III,
and
the
commenter
believed
that
EPA's
grouping
of
units
under
bituminous/
subbituminous
categories
may
be
erroneous
in
certain
cases.
The
commenter
provided
a
table
of
the
coal
Btu
values
from
the
ICR
III
test
reports
for
the
four
units
used
in
setting
the
MACT
level
for
subbituminous
coal.
If
the
ASTM
guidelines
on
Btu
content
were
to
be
used,
three
of
those
four
(
i.
e.,
AES
Hawaii,
Clay
Boswell
Unit
2,
Cholla
Unit
3)
units
clearly
fall
under
the
bituminous
category,
rather
than
subbituminous
category.
This
raises
questions
about
the
validity
of
the
proposed
MACT
levels
for
subbituminous
coal,
and
raises
a
similar
problem
for
the
cap­
and­
trade
proposal.

The
commenter
is
aware
of
the
uncertainty
with
the
type
of
coal
used
(
and
associated
potential
misclassification)
during
the
ICR
III
tests
at
the
Valmont
Plant
in
Colorado
reported
by
Xcel
Energy.
Data
from
that
plant
was
used
to
calculate
the
MACT
level
for
the
bituminous
coal
category.
However,
had
the
coal
indeed
been
subbituminous
(
rather
than
the
assumed
bituminous),
the
proposed
MACT
levels
for
both
bituminous
and
subbituminous
would
be
significantly
different.

The
commenter
stated
that,
based
on
the
new
information
on
the
possible
misclassification
of
coal
ranks
in
the
ICR
III
Database
presented
here,
they
believed
that
EPA
should
reassess
the
MACT
levels
and
cap­
and­
trade
allowance
allocations
included
in
the
proposed
Hg
rulemaking.
This
commenter
believed
that
EPA
should
address
the
unique
compliance
uncertainty
created
for
several
Western/
Southwestern
plants
using
certain
coals
whose
heating
value
(
Btu)
falls
in
the
overlap
area
for
bituminous
and
subbituminous
coal
ranks.
Therefore,
should
EPA
retain
the
coal
rank­
based
approach
to
regulate
Hg
emissions,
the
commenter
recommends
that
EPA
use
the
same
Hg
emissions
limitation
for
low
Cl
content
Western
bituminous
coal
and
subbituminous
coal.

The
commenter
also
believed
that
the
Cl
content
of
the
coal
is
a
better
basis
for
regulating
Hg
emissions
than
the
proposed
coal
rank­
based
approach,
which
relies
on
the
ASTM
methodology
that
was
never
intended
and
is
not
appropriate
for
characterizing
Hg
emissions.
Finally,
in
the
event
that
EPA
retains
the
coal
rank­
based
approach
of
regulating
Hg
emissions,
this
commenter
recommends
that
plants
using
Western
bituminous
coal
be
subjected
to
MACT
levels
and
allowance
allocations
identical
to
those
plants
using
subbituminous
coals.

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

Commenter
OAR­
2002­
0056­
5548
noted
that
commenter
OAR­
2002­
0056­
2535/
5505
had
urged
EPA
to
reevaluate
the
MACT
determination
for
Wyoming
subbituminous
coals
to
9­
157
account
for
large
differences
in
Wyoming
PRB
and
other
western
subbituminous
coals.
Commenter
OAR­
2002­
0056­
2535/
5505
is,
in
effect,
asking
EPA
to
further
subcategorize
subbituminous
coals
based
on
differences,
such
as
a
distinction
between
ASTM
sub­
classifications
within
the
subbituminous
rank,
as
they
discuss
in
their
comments.
Commenter
OAR­
2002­
0056­
5548
believed
that
the
commenter
OAR­
2002­
0056­
2535/
5505'
s
argument
points
out
one
of
the
fundamental
flaws
with
the
attempt
to
subcategorize
by
coal
rank,
because
rank
is
not
predicative
of
coal
properties
of
relevance
to
Hg
emissions
and
control.
Furthermore,
if
EPA
were
to
do
so
for
subbituminous
coal,
it
also
must
further
subcategorize
bituminous
coals
based
on
the
even
greater
differences
in
bituminous
coals
from
different
regions
of
the
country.
Commenter
OAR­
2002­
0056­
5548
believes
that,
at
a
minimum,
EPA
should
subcategorize
bituminous
coals
by
rank
(
High
volatile
A,
B,
and
C,
medium
volatile,
and
low
volatile),
and
further
by
geographic
region
(
western,
mid­
continent,
northern,
central,
and
southern
Appalachia).
Within
these
regions,
bituminous
coals
are
produced
from
individual
seams
which
themselves
exhibit
large
differences
in
coal
properties.
A
decision
by
EPA
to
further
subcategorize
one
rank
coal
without
doing
so
for
all
ranks
of
coal
would
clearly
be
arbitrary
and
would
fail
to
ensure
an
equitable
treatment
for
coals
of
all
ranks,
which
EPA
states
as
one
of
its
objectives.

In
its
original
comments
on
the
rule
and
in
these
NODA
comments,
commenter
OAR­
2002­
0056­
5548
demonstrated,
using
the
IRC
Part
II
coal
analysis
data,
that
62
percent
of
all
subbituminous
coals
sampled
would
meet
the
proposed
5.8
lb/
TBtu
MACT
limit
with
no
Hg
reduction,
largely
eliminating
the
speciation
or
any
other
control
issue.
The
average
subbituminous
coal
has
a
Hg
content
of
5.7
lb/
TBtu,
thus
making
subbituminous
coal,
in
aggregate,
a
compliance
coal,
given
the
proposed
12­
month
averaging
period
of
the
rule.

In
its
comments,
commenter
OAR­
2002­
0056­
2535/
5505
attempts
to
refute
this
compliance
coal
demonstration
by
presenting
ICR
Part
III
emissions
data
from
10
plants
burning
Wyoming
PRB
coal,
purporting
to
show
that
Hg
emissions
from
the
majority
of
these
plants
are
in
excess
of
the
5.8
lb/
TBtu
limit.
EPA
should
discount
this
for
two
reasons.
First,
commenter
OAR­
2002­
0056­
2535/
5505
acknowledges
in
its
comments
that
the
ICR
Part
III
data,
which
consists
of
only
short­
term
sampling
at
80
power
plants,
is
highly
suspect.
Commenter
OAR­
2002­
0056­
5548
strongly
concurred
with
that
observation
and
point
out
that
none
of
the
units
that
meet
the
data
quality
criteria
burns
a
Wyoming
PRB
coal.
Therefore,
the
attempts
of
commenter
OAR­
2002­
0056­
2535/
5505
to
use
the
ICR
Part
III
data
to
support
a
conclusion
concerning
plant
emissions
contradicts
their
clear
understanding
of
the
limitations
of
the
ICR
Part
III
data.

Second,
the
IRC
Part
II
data
set,
on
which
commenter
OAR­
2002­
0056­
2535/
5505
relied,
is
much
more
substantial
and
robust,
because
it
contains
the
Hg
contents
of
thousands
of
coal
samples
from
most
mines,
sampled
as
delivered
to
most
power
plants
in
the
country
for
a
full
year.
Commenter
OAR­
2002­
0056­
5548
provided
a
table
reporting
the
mean
and
median
Hg
contents
from
the
ICR
Part
II
data
base
for
the
509
coal
shipments
sampled
as
delivered
to
the
nine
plants
for
which
commenter
OAR­
2002­
0056­
2535/
5505
presented
emissions
data.
Contrary
to
the
SEC's
assertion,
six
of
the
nine
plants
(
67
percent)
received
coals
in
compliance
with
the
proposed
5.8
lb/
TBtu
limit
in
1999,
and
the
three
that
did
not
would
require
an
average
reduction
of
only
10
percent
to
come
into
compliance.
That
reduction
is
well
within
the
range
of
9­
158
EEI/
CRA's
subbituminous
EMF
for
a
CS­
ESP.
Thus,
assuming
only
a
modest
reduction
across
existing
emission
control
equipment,
these
plants
would
require
no
further
reduction
to
come
into
compliance.
The
average
Hg
content
of
coals
delivered
to
the
same
nine
plants
in
commenter
OAR­
2002­
0056­
2535/
5505'
s
comments
was
5.2
lb/
TBtu,
further
supporting
the
commenter
OAR­
2002­
0056­
5548'
s
conclusion
that
the
5.8
lb/
TBtu
MACT
limit
effectively
would
denominate
subbituminous
coals
as
compliance
coals.

Commenter
OAR­
2002­
0056­
2535/
5505
stated
that
"
elemental
mercury
comprises
70­
80
percent
for
the
total
mercury
emitted
from
the
furnace"
for
subbituminous
coal­
fire
units.
They
do
not
provide
a
source
for
this
statement,
but
it
appears
to
overstate
the
percentage
of
elemental
Hg
in
the
flue
gas
of
such
units.
An
analysis
of
the
ICR
Part
III
data
for
Hg
speciation
at
the
inlet
to
the
last
control
device
at
each
subbituminous­
coal­
fired
station
reveals
an
average
elemental
Hg
concentration
of
59
±
23
percent.
Some
particulate
or
oxidized
Hg
may
have
been
removed
ahead
of
the
flue
gas
measurement
point,
so
this
should
be
considered
an
upper
bound
on
the
average
percentage
of
elemental
Hg
in
the
flue
gas
for
subbituminous
coal­
fired
units.
Note
that
this
average
excludes
those
plants
identified
by
commenter
OAR­
2002­
0056­
2535/
5505
as
misidentified
by
the
EPA
as
burning
only
subbituminous
coal.

Commenter
OAR­
2002­
0056­
2535/
5505
contended
that
the
imputed
emission
factors
calculated
from
EPA's
proposed
allowance
adjustment
factors
under
section
111
results
in
"
relatively
little"
subcategorization.
Commenter
OAR­
2002­
0056­
5548
opposes
the
imposition
of
any
allowance
adjustment
factors.
The
commenter
believed
that
too
little
is
known
at
present
about
Hg
emissions
and
control
technology
to
ensure
that
they
are
equitable
and
result
in
achievable
emission
limits
(
a
position
with
which
commenter
OAR­
2002­
0056­
2535/
5505
concurs).
The
commenter
also
contended
the
development
of
Hg­
specific
control
technology
will
obviate
the
rationale
for
allowance
adjustments
in
the
future.
Nevertheless,
commenter
OAR­
2002­
0056­
2535/
5505
would
support
the
use
of
EPA's
section
112
MACT
limits
as
the
basis
for
allowance
adjustment
factors.
This
would
simply
create
under
the
guise
of
a
cap­
and­
trade
program
the
same
inequity
as
in
the
MACT
proposal,
under
which
subbituminous
coal
fired
units
would
receive
sufficient
allowances
as
to
require
no
Hg
reductions,
and
most
likely
receive
excess
allowances
from
which
they
would
profit
by
selling
them
to
bituminous
coal­
fired
units
which
face
a
stringent,
and
in
some
cases
unachievable,
compliance
burden.

Response:

EPA
believes
that
the
comments
provided
by
commenters
OAR­
2002­
0056­
5494
and
­
5548
relate,
variously,
to
the
issues
of
subcategorization
(
either
more
or
fewer
subcategories)
and
the
use
of
the
ASTM
ranking
scheme
to
delineate
the
subcategories,
rather
to
the
issue
of
Hg
speciation.
EPA
has
addressed,
earlier
in
this
document,
other
comments
related
to
the
issue
of
subcategorization
and
has
presented
its
rationale
for
the
use
of
subcategories.

We
are,
however,
somewhat
perplexed
regarding
the
comments
related
to
a
utility
"
not
knowing"
the
rank
of
coal
being
fired
and
on
the
use
of
the
ASTM
classification
methodology
as
the
basis
for
determining
the
rank
of
coal
burned,
and,
thus,
"
membership"
in
the
appropriate
subcategory.
EPA
based
its
subcategorization
on
the
coal
rank
information
provided
by
the
9­
159
utility,
not
on
the
coal
analysis
data
provided
by
the
utility.
That
is,
if
a
utility
reported
that
their
coal
was
(
e.
g.)
"
subbituminous,"
EPA
did
not
question
the
statement.
During
the
period
of
the
ICR,
EPA
requested
that
the
responding
utilities
provide
to
EPA
only
the
Hg­
and
Clcontents
of
their
coals
as
new
information.
The
remaining
coal
information
requested
(
e.
g.,
coal
rank;
heating
value;
moisture,
ash,
and
sulfur
content)
was
that
information
already
being
provided
to
the
DOE.
Each
U.
S.
utility
company
(
including
combined
heat
and
power
companies)
is
required
by
law
to
submit
to
the
DOE/
EIA
for
each
Utility
Unit
the
rank
of
coal
burned,
on
a
monthly
or
annual
basis,
on
at
least
one
of
the
following
forms:

EIA
Form­
423:
Monthly
Cost
and
Quality
of
Fuels
for
Electric
Plants
Report
("
Column
`
c'Fuel)
EIA
Form­
767:
Steam­
Electric
Plant
Operation
and
Design
Report
("
Fuel
Code")
EIA
Form­
860:
Annual
Electric
Generator
Report
("
Energy
Source
Code")
EIA
Form­
860m:
Monthly
Update
to
the
Annual
Electric
Generator
Report
("
Energy
Source
Code")
EIA
Form­
906:
Power
Plant
Report
("
Energy
Source")
EIA
Form­
920:
Combined
Heat
and
Power
Plant
Report
("
Energy
Source")

Thus,
utility
companies
are
currently
obtaining
the
coal
rank
information
being
reported
to
DOE
from
someone,
somehow
to
comply
with
this
legal
requirement.
EPA
is
not
asking
for
any
additional
information
or
analyses
upon
which
to
establish
a
given
Utility
Unit
in
a
subcategory
for
purposes
of
either
the
final
NSPS
or
cap­
and­
trade
provisions.
Rather
than
being
able
to
"
game"
the
system,
units
that
blend
two
or
more
ranks
of
coal
are
required
to
use
specified
procedures
for
determining
their
applicable
NSPS
emission
limit.

EPA
continues
to
believe
that
the
ASTM
ranking
methodology
is
the
one
most
widely
recognized
within
the
industry
and,
therefore,
is
appropriate
for
this
rulemaking.
Given
the
existing
legal
requirement
to
provide
DOE
with
the
coal
rank
being
utilized,
EPA
believes
that
the
industry
knows
what
coal
rank
it
is
consuming
in
its
units.

2.
EPA
sought
comment
on
if/
when
a
standard
(
or
average)
speciation
profile
should
be
used
for
either
the
CAA
section
111
or
CAA
section
112
regulatory
approach.

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
stated
that
under
Part
II,
Sub­
Part
C
of
the
NODA,
EPA
indicates
that
it
received
comments
related
to
the
speciation
of
Hg.
The
commenter
stated
that
speciation
is
fundamentally
important
since
the
ability
of
control
devices
to
remove
Hg
is
directly
related
to
the
form
of
Hg
in
the
flue
gas.
The
three
species
of
Hg
that
exist
in
plant
emissions
are
elemental,
ionic/
oxidized,
and
particulate.
Oxidized
and
particulate
are
known
to
be
the
more
easily
captured
forms
of
Hg.
Average
Hg
speciation
data
from
the
81
power
plants
that
were
the
basis
of
the
MACT
floor
calculations,
is
set
forth
in
the
NODA
(
69
FR
69871).
The
calculated
averages
of
the
speciated
Hg
forms
across
all
coal
types
were:
54
percent
elemental,
9­
160
43
percent
oxidized,
and
3
percent
particulate.

Response:

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
objected
to
the
notion
of
using
an
average
speciation
profile
to
predict
the
characteristics
of
Hg
emissions
from
coal
fired
utilities.
The
percentages
of
the
three
forms
of
Hg
emissions
can
vary
widely
from
facility
to
facility,
even
in
the
same
coal
category.
For
example,
it
has
been
determined
that
within
a
given
coal
category
the
proportion
of
oxidized
Hg
emitted
is
proportional
to
the
Cl
content
of
the
coal.
Commenter
OAR­
2002­
0056­
2038
noted
that
average
speciation
for
electric
utilities
range
between
10
percent
and
90
percent
for
the
oxidized
form.
The
Brookhaven
National
Laboratory's
May
2003
study
utilized
data
from
the
Bruce
Mansfield
Plant
in
Shippingport,
PA,
and
the
Monticello
Power
Plant
in
Monticello,
TX.
The
fraction
of
the
oxidized
form
of
Hg
between
these
two
plants
varied
between
19.7
percent
and
60.4
percent,
respectively.
Given
the
disparate
speciation
data
that
exists
for
Hg
emissions,
this
commenter
recommends
that
a
sensitivity
analysis
be
performed
to
evaluate
the
effect
that
the
range
of
values
for
the
oxidized
form
of
Hg
has
on
the
proposed
rule.

Response:

EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.

Comment:

Two
commenters
(
OAR­
2002­
0056­
5510,
­
5548)
said
that
an
average
speciation
profile
cannot
capture
the
large
degree
of
variability
and
uncertainty
associated
emissions
from
different
coal
types,
and
should
not
be
used
for
either
section
111
or
112
regulation.

In
the
case
of
MACT
regulation,
if
the
standard
is
set
based
upon
an
average
speciation
profile,
coals
with
greater
Hg
concentrations
will
not
be
able
to
comply
 
even
if
the
unit
is
meeting
a
targeted
percentage
reduction.
For
example,
the
average
Hg
content
of
bituminous
coal
reported
in
the
ICR
Part
II
data
is
8.4
lb/
TBtu.
Assuming
the
availability
of
a
Hg
control
9­
161
technology
able
to
achieve
50
to
70
percent
reduction
(
DOE's
goal
for
2010),
the
"
average"
bituminous
coal
could
achieve
an
emission
rate
of
2.5
to
4.2
lb/
TBtu.
However,
coals
from
the
State
of
Ohio,
which
have
an
average
Hg
concentration
of
15.7
lb/
TBtu,
would
need
to
achieve
75
to
85
percent
removal
to
meet
a
standard
in
this
range,
beyond
the
range
of
the
hypothetical
then­
available
technology.
As
a
result,
these
coals
could
not
be
used
in
compliance
with
the
MACT.

Although
this
risk
may
be
somewhat
lessened
under
a
cap­
and­
trade
rule,
because
operators
have
the
potential
ability
to
purchase
allowances,
there
is
no
assurance
that
allowances
will
be
available
in
sufficient
quantity
to
meet
compliance
needs.
To
the
degree
that
allowances
are
not
available,
the
explicit
compliance
problem
under
the
MACT
described
above
becomes
effectively
the
same
liability
under
the
cap­
and­
trade
program.

Response:

EPA
is
finalizing
a
cap
and
trade
rule.
Please
see
the
CAMR
preamble
for
a
complete
discussion.
EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
using
average
vs.
individual
power
plant
speciation
in
modeling
and
used
individual
speciation
in
the
model
runs
conducted
for
it
to
gain
insights
into
the
potential
changes
in
deposition
patterns
as
a
result
of
different
Hg
emission
reduction
scenarios.
The
commenter
recommends
that
EPA
do
the
same
to
develop
similar
insights,
as
these
are
important
to
inform
decisions
on
cap­
and­
trade
vs.
MACT.

Response:

EPA
is
finalizing
a
cap
and
trade
rule.
Please
see
the
CAMR
preamble
for
a
complete
discussion.
EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.

Comment:
9­
162
One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
given
the
repeated
concerns
voiced
about
Hg
"
hot
spots,"
it
makes
sense
to
use
the
best
estimates
of
Hg
speciation
in
any
dispersion
modeling.
EPA's
1999
ICR
request
produced
a
year
of
detailed
coal
data
for
all
coal­
fired
power
plants
in
the
U.
S.
These
coal
data
can
be
used
along
with
Hg
speciation
correlations
that
EPRI
developed
from
the
1999
ICR
Hg
stack
sampling
to
produce
Hg
speciation
estimates
for
every
coal­
fired
unit
in
the
country.
This
is
exactly
how
EPRI
modeled
Hg
deposition
in
the
U.
S.
EPRI's
modeling
results
were
provided
in
EPRI
CAMR
comments
dated
June
16,
2004
and
in
the
comments
EPRI
is
submitting
in
response
to
this
NODA.
The
commenter
believes
that
EPA
should
follow
a
similar
approach
in
any
Hg
deposition
modeling
it
may
perform.
EPA
should
not
use
an
average
speciation
value
for
each
coal
rank.

Response:

EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.
EPA
has
addressed
the
hot
spots
issue
in
the
revision
Federal
Register
notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

3.
Is
it
currently
feasible,
or
will
it
be
feasible
within
the
compliance
timeframes
of
the
proposed
rule,
to
accurate
monitor
a
source's
Hg
emissions
by
species?

Comment:

As
part
of
the
commenter's
(
OAR­
2002­
0056­
5490)
Mercury
Research
Program,
they
had
purchased
two
Hg
CEMS.
The
analyzers,
manufactured
by
Nippon,
are
"
dry"
monitors
and
appeared
to
be
fairly
reliable.
Most
of
the
problems
that
the
commenter
saw
had
been
in
the
sample
conditioning
system.
A
great
deal
of
effort
had
gone
into
increasing
the
reliability
of
the
sample
conditioning
system.
High
temperatures
had
to
be
maintained
throughout
or
fouling
of
the
glassware
would
occur.
The
commenter
has
installed
a
completely
glass­
lined
probe
to
help
maintain
closer
tolerances
with
sampling
temperatures.
Even
with
all
the
effort
put
into
making
the
system
run
reliably,
they
are
only
getting
about
5
days
of
continuous
operation
without
significant
maintenance.
Until
these
problems
are
resolved,
it
will
not
matter
if
the
monitor
can
measure
speciated
Hg.
The
commenter's
Hg
CEMS
are
capable
of
measuring
speciated
(
elemental
and
oxidized)
Hg.

Response:

EPA
believes
that
field
tests
have
demonstrated
Hg
CEMS
to
be
accurate
and
reliable.
The
Hg
CEMS
have
performed
adequately
for
several
months
and
meet
the
Ontario­
Hydro
9­
163
Reference
Method
specifications.
Furthermore,
several
dry
chemistry
Hg
CEMS
are
currently
being
tested
at
sites
that
represent
the
most
challenging
conditions
and
the
Agency
plans
to
share
with
industry
the
results
of
such
experiences
to
facilitate
the
selection
of
appropriate
monitoring
methodology.
EPA
also
agrees
with
the
commenter
that
the
sample
conditioning
system
provides
one
of
the
most
challenging
aspects
of
operating
a
successful
Hg
CEMS,
but
feels
confident
that
substantial
advancement
of
the
sample
conditioning
system
will
occur
before
the
implementation
of
the
rule
and
as
other
monitoring
techniques
may
become
available,
is
allowing
the
use
of
systems
that
can
meet
performance­
based
specifications.

The
final
rule
requires
the
measurement
of
total
vapor
phase
Hg,
but
does
not
require
separate
monitoring
of
speciated
Hg
emissions
(
i.
e.,
elemental
and
ionized
Hg).
Because
of
the
potential
impact
of
Hg
speciation
on
local
versus
broader
geographical
deposition,
the
Agency
considers
separate
monitoring
of
these
emissions
as
a
need
to
be
addressed.
However,
at
least
two
current
monitoring
technologies
can
accurately
monitor
speciated
Hg
emissions.
The
Agency
will
continue
to
test
speciated
Hg
monitoring
technologies.
If
these
technologies
are
adequately
demonstrated,
the
Agency
may
consider
a
proposed
rulemaking
within
four
to
five
years
after
program
implementation,
which
should
provide
enough
lead
time
for
development
and
installation
of
these
monitoring
systems.

Comment:

One
commenter
(
OAR­
2002­
0056­
5510)
noted
that
speciated
Hg
emissions
can
currently
be
measured
via
the
Ontario
Hydro
Method.
However,
when
the
tests
are
being
conducted
specific
attention
must
be
provided
to
the
experimental
method
to
ensure
data
reliability.
As
pointed
out
in
the
commenter's
May
14,
2004,
comments,
EPA's
IGR
Part
III
data
contain
many
instances
of
incomplete
or
invalid
testing.

CEMS,
or
semi­
continuous
methods
like
proposed
EPA
Method
324,
for
the
measurement
of
total
Hg
emissions
are
projected
to
be
available
in
the
2008
time
frame
and
would
be
sufficient
to
demonstrate
compliance
with
the
proposed
standards.
The
commenter
believed
adequate
information
can
be
gathered
using
CEMS
or
semi­
continuous
methods
for
total
Hg
emissions,
combined
with
periodic
Ontario
Hydro
sampling
for
speciated
emissions
profiles,
if
adequate
methods
for
monitoring
speciated
Hg
are
not
developed
by
that
time.

As
noted
in
the
commenter's
May
14,
2004,
comments,
adequate
technical
data
do
not
exist
at
this
time
to
provide
a
reasoned
basis
for
the
allocation
of
allowances
among
coal
types
for
purposes
of
an
initial
reduction
in
2010.
For
this
reason,
the
commenter
recommended
that
Hg
monitoring
begin
on
affected
units
in
the
2008
time
frame
in
order
to
determine
prospective
emissions
allocations
by
coal
type
for
an
interim
2015
emissions
cap.
The
analysis
required
for
setting
appropriate
allocations
will
necessarily
require
speciated
emissions
information
over
the
full
range
of
operational
conditions
including
emissions
during
partial
load,
transient
operations
and
during
maintenance
events.

Response:
9­
164
The
final
rule
requires
the
measurement
of
total
vapor
phase
Hg,
but
does
not
require
separate
monitoring
of
speciated
Hg
emissions
(
i.
e.,
elemental
and
ionized
Hg).
Because
of
the
potential
impact
of
Hg
speciation
on
local
versus
broader
geographical
deposition,
the
Agency
considers
separate
monitoring
of
these
emissions
as
a
need
to
be
addressed.
However,
at
least
two
current
monitoring
technologies
can
accurately
monitor
speciated
Hg
emissions.
The
Agency
will
continue
to
test
speciated
Hg
monitoring
technologies.
If
these
technologies
are
adequately
demonstrated,
the
Agency
may
consider
a
proposed
rulemaking
within
four
to
five
years
after
program
implementation,
which
should
provide
enough
lead
time
for
development
and
installation
of
these
monitoring
systems.

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
future
availability
of
speciating
continuous
Hg
monitors.
Assuming
the
developers
(
and
future
suppliers)
of
continuous
Hg
monitors
are
successful
in
developing
accurate,
reliable
and
robust
instruments
for
near­
continuous
measurements
of
total
Hg,
they
should
be
able
to
enhance
these
to
also
provide
near­
continuous
speciated
measurements
with
1
to
2
years
after
commercialization
of
the
total
Hg
monitors.

Response:

At
least
two
current
monitoring
technologies
can
accurately
monitor
speciated
Hg
emissions.
EPA
agrees
with
the
commenter
and
the
Agency
will
continue
to
test
speciated
Hg
monitoring
technologies.
If
these
technologies
are
adequately
demonstrated,
the
Agency
may
consider
a
proposed
rulemaking
within
four
to
five
years
after
program
implementation,
which
should
provide
enough
lead
time
for
development
and
installation
of
these
monitoring
systems.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
stated
that
EPA's
specific
question
about
whether
it
is
currently
feasible,
or
will
be
feasible
within
the
compliance
time
frames
of
the
proposed
rule,
to
accurately
monitor
a
source's
Hg
emissions
by
species
is
irrelevant.
EPA
has
already
stated
that
continuous
Hg
monitors
that
measure
total
Hg
have
been
validated
and
will
be
required
for
compliance
with
the
final
rule.
Total
Hg
emissions
must
be
reduced
from
these
sources.

Response:

The
final
rule
requires
the
measurement
of
total
vapor
phase
Hg,
but
does
not
require
separate
monitoring
of
speciated
Hg
emissions
(
i.
e.,
elemental
and
ionized
Hg).
Because
of
the
potential
impact
of
Hg
speciation
on
local
versus
broader
geographical
deposition,
the
Agency
considers
separate
monitoring
of
these
emissions
as
a
need
to
be
addressed.
However,
at
least
two
current
monitoring
technologies
can
accurately
monitor
speciated
Hg
emissions.
The
Agency
will
continue
to
test
speciated
Hg
monitoring
technologies.
If
these
technologies
are
adequately
demonstrated,
the
Agency
may
consider
a
proposed
rulemaking
within
four
to
five
years
after
9­
165
program
implementation,
which
should
provide
enough
lead
time
for
development
and
installation
of
these
monitoring
systems.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
although
the
Ontario­
Hydro
Method
(
ASTM
Method
D6784­
02)
provides
only
short­
term
emissions
data,
it
is
currently
capable
of
providing
accurate
and
repeatable
data
on
Hg
emissions
at
the
stack
by
species.
The
commenter
believed
that
speciated
data
collected
by
EPA
pursuant
to
its
Hg
ICR
using
the
Ontario­
Hydro
Method
clearly
documents
the
need
for
subcategorization
of
the
utility
industry
based
on
coal
type
in
any
final
MACT
rule.

As
for
continuous
monitoring
of
Hg
emissions
by
species,
there
is
no
commercially
available
monitor
capable
of
providing
Hg
emissions
data
by
species,
and
there
is
almost
no
possibility
that
a
such
a
monitor
will
become
available
within
the
compliance
timeframe
of
the
proposed
rules.
A
number
of
tasks
remain
to
be
completed
before
the
existing
Hg
CEMS
(
all
of
which
measure
total
Hg)
can
be
deemed
sufficiently
accurate
and
reliable
for
use
in
the
proposed
regulatory
programs.

Response:

At
least
two
current
monitoring
technologies
can
accurately
monitor
speciated
Hg
emissions.
The
Agency
will
continue
to
test
speciated
Hg
monitoring
technologies.
If
these
technologies
are
adequately
demonstrated,
the
Agency
may
consider
a
proposed
rulemaking
within
four
to
five
years
after
program
implementation,
which
should
provide
enough
lead
time
for
development
and
installation
of
these
monitoring
systems.
The
final
rule
requires
the
measurement
of
total
vapor
phase
Hg,
but
does
not
require
separate
monitoring
of
speciated
Hg
emissions
(
i.
e.,
elemental
and
ionized
Hg).
Because
of
the
potential
impact
of
Hg
speciation
on
local
versus
broader
geographical
deposition,
the
Agency
considers
separate
monitoring
of
these
emissions
as
a
need
to
be
addressed.

C.
EPA's
Proposed
Revised
Benefits
Assessment
General
Comments
concerning
EPA's
Proposed
Revised
Benefits
Assessment
Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
agreed
that
EPA
should
improve
its
estimate
of
human
exposure
to
Hg
that
arises
from
power
plant
emissions.
The
commenter
stated
that
two
notes
of
caution
must
be
sounded,
however.

The
commenter
stated
that
first,
the
proposed
revised
benefits
assessments
methodology
described
in
the
NODA
will
not
cure
the
fundamental
defects
in
the
proposed
CAMR.
The
commenter
pointed
out
that,
for
example,
the
revised
methodology
does
not
address,
let
alone
9­
166
remedy,
EPA's
failure
to
calculate
a
proper
Section
112
MACT
floor.
And,
the
commenter
added,
as
long
as
EPA
continues
to
underestimate
the
benefits
associated
with
a
proper
Section
112
approach,
it
will
continue
to
overestimate
the
comparative
benefits
of
its
proposed
Section
111
approach.
The
commenter,
therefore,
reiterated
that
EPA
should
focus
its
energies
on
remedying
the
problems
with
its
Section
112
proposal.

The
commenter
further
stated
that
second,
EPA
cannot
and
should
not
delay
regulation
until
all
alleged
scientific
uncertainties
concerning
power
plant
Hg
emissions
have
been
resolved.
The
commenter
stated
that,
to
the
contrary,
to
the
extent
uncertainties
exist
concerning
Hg
speciation,
deposition,
transport
and
exposure,
EPA
should
err
on
the
side
of
caution
so
as
to
fulfill
the
preventive
and
precautionary
purposes
of
the
Clean
Air
Act.
See
American
Lung
Ass'n,
134
F.
3d
at
389;
Lead
Industries
Ass'n,
647
F.
2d
at
1155;
see
also
42
U.
S.
C.
§
7412(
d)(
2)
(
requiring
EPA
to
impose
emissions
standards
that
"
require
the
maximum
degree
of
reduction
in
emissions.
.
.").
The
commenter
added
that,
furthermore,
as
previously
noted,
EPA
is
required
to
regulate
power
plant
emissions
promptly.

Response:

EPA
appreciates
the
commenters
concerns.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112.
For
a
discussion
of
our
exposure
modeling,
please
see
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
and
the
Regulatory
Impact
Analysis
in
the
docket.

Comment:

With
regard
to
the
first
three
steps
of
the
proposed
revised
benefits
assessment
methodology,
the
commenter
(
OAR­
2002­
0056­
5460)
reiterated
that
EPA
should
not
allow
any
alleged
uncertainties
in
the
scientific
evidence
to
prevent
it
from
regulating
power
plant
Hg
emissions
in
a
manner
adequate
to
protect
human
health
and
the
environment.
The
commenter
stated
that
existing
science
confirms
the
need
to
regulate
power
plant
emissions
and
any
scientific
uncertainties
should
be
resolved
in
favor
of
more
protective
requirements.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
Chapters
10
and
11
of
the
CAMR
Regulatory
Impact
Analysis
for
a
discussion
of
the
exposure
modeling
and
benefit
methodologies
used
to
analyze
the
benefits
associated
with
this
rulemaking.

Comment:
9­
167
Two
commenters
(
OAR­
2002­
0056­
5365,
­
5404)
supported
EPA's
proposed
general
methodology
for
revising
its
assessment
of
the
benefits
associated
with
Hg
emissions
reductions
from
power
plants.
The
commenters
believed
that
the
revised
benefits
assessment
methodology
generally
is
an
appropriate,
reasonably
accurate
quantification
of
benefits
associated
with
the
implementation
of
EPA's
proposed
regulation
of
Hg
emissions
(
See
69
Fed.
Reg.
69864,
69872.).
In
particular,
the
commenters
supported
EPA's
revised
methodology
insofar
as
it
focuses
on
quantification
of
benefits
from
Hg
reductions
(
See
69
Fed.
Reg.
at
69873.).
According
to
the
commenters,
that
is,
the
Agency's
requests
for
further
comment
in
the
NODA
indicate
that
EPA's
benefits
analysis
appropriately
has
shifted
toward
issues
that
are
central
to
the
purpose
of
the
Hg
regulation,
in
particular,
changes
in
human
exposure
to
Hg
as
a
result
of
the
emissions
reductions
that
will
be
required
by
the
rule,
and
potential
consequent
changes
in
public
health
(
See
69
Fed.
Reg.
at
69876.).

The
commenters
stated
that
by
contrast,
EPA's
benefits
assessment
in
the
NPR
dated
Jan.
30,2004,
as
well
as
EPA's
conclusion
that
the
benefits
of
the
proposed
rule
far
outweigh
the
costs,
was
essentially
faulty
and
misleading
in
that
the
assessment
and
its
consequent
conclusions
were
premised
on
tangential
and/
or
irrelevant
information.
According
to
the
commenters,
for
example,
in
the
NPR
dated
January
30,2004,
EPA
predicted
that
the
implementation
of
Hg
MACT
would
result
in
benefits
equal
to
$
15
billion
which
would
be
offset
by
costs
equal
to
less
than
$
2
billion
 
a
net
benefit
valued
at
greater
than
$
13
billion.
The
commenters
stated
that
EPA's
figures
are
misleading,
however,
because
none
of
the
quantified
benefit
is
attributable
to
EPA's
proposed
Hg
regulation.
According
to
the
commenters,
rather,
the
benefit
reflects
ancillary
NO
x
and
SO
2
reductions
expected
to
be
achieved
as
co­
benefits
resulting
from
the
operation
of
MACT­
imposed
Hg
controls.
The
commenters
stated
that
in
any
event,
according
to
EPA,
"
most
or
all
of
the
ancillary
benefits
of
control
would
be
achieved
anyway,
regardless
of
whether
a
section
112
MACT
is
promulgated."
See
69
Fed.
Reg.
at
4711
("[
E]
ven
if
no
[
mercury]
controls
were
imposed
[
pursuant
to
the
rule­
making],
most
major
coal­
fired
units
would
have
to
reduce
their
SO
2
and
NO
x
emissions
as
part
of
the
effort
to
bring
the
nation
into
attainment
with
new
air
quality
standards.").
According
to
the
commenters,
considering
the
foregoing,
EPA's
benefits
assessment
in
the
NPR
is
of
limited
value,
because
it
quantifies
only
benefits
that
are
ancillary
to
the
core
purpose
of
the
proposed
rule
and
are
likely
to
be
realized
in
any
case.
The
commenters
believed
that
it
is
fundamentally
inappropriate
to
justify
a
rule
 
as
EPA
did
in
the
NPR
 
based
on
emissions
reductions
that
are
not
related
to
the
central
purpose
of
the
rule
and
that
are
likely
to
occur
whether
or
not
the
rule
is
promulgated.
Thus,
in
response
to
EPA's
requests
for
comment
regarding
the
revised
benefits
assessment,
the
commenters
strongly
believed
that
the
Agency
must
focus
on
quantifying
benefits
that
are
central
to
the
purpose
of
the
regulation.

As
such,
the
commenters
supported
the
overall
methodology
outlined
in
the
NODA,
which
will
enable
EPA
to
assess
the
potential
public
health
benefits
associated
with
reducing
Hg
emissions
from
power
plants,
i.
e.,
the
benefits
to
public
health
that
are
related
to
the
purpose
of
this
rule.
According
to
the
commenters,
such
quantification
is
admittedly
difficult,
as
there
is
no
direct
correlation
between
power
plant
Hg
emissions
and
human
MeHg
exposure
(
which,
as
EPA
recognizes,
is
the
public
health
outcome
of
concern).
As
such,
the
commenters
concurred
with
EPA
that
the
Agency
must
undertake
the
following
five­
step
assessment
in
order
to
translate
9­
168
power
plant
Hg
emissions
reductions
into
public
health
outcomes:
(
I)
quantify
Hg
emissions
projected
from
power
plants
under
the
Base
Case
as
compared
to
after
implementation
of
the
Hg
rule,
including
quantifying
Hg
emissions
that
result
from
sources
other
than
U.
S.
coal­
fired
plants;
(
ii)
model
changes
atmospheric
dispersion,
atmospheric
speciation,
and
Hg
deposition
as
a
result
of
Hg
reductions
from
power
plants;
(
iii)
model
the
link
between
changes
in
Hg
deposition
and
changes
in
MeHg
concentrations
in
fish;
(
iv)
assess
types
and
amounts
offish
consumed
by
U.
S.
customers
and
extrapolate
resulting
changes
in
MeHg
exposures
resulting
from
reduced
power
plant
Hg
emissions;
and
(
v)
assess
how
reductions
in
MeHg
exposure
affect
human
health.

Although
the
commenters
supported
the
overall
methodology
EPA
has
articulated,
and
concurred
that
the
Agency
has
properly
identified
the
five
necessary
steps
to
enable
quantification
of
the
public
health
benefits
associated
with
the
proposed
rule,
the
commenters
also
supported
the
concerns
articulated
by
the
Electric
Power
Research
Institute
("
EPRI")
and
others
with
respect
to
specific
aspects
of
how
EPA
proposes
to
conduct
specific
aspects
of
the
benefits
assessment.
For
example,
the
commenters
concurred
with
EPRI
that
there
are
some
significant
weaknesses
in
how
the
MMAPs
model
quantifies
the
link
between
changes
in
Hg
deposition
and
changes
in
MeHg
concentrations
in
fish.
The
commenters
urged
EPA
to
seriously
consider
these
critiques
of
specific
aspects
of
the
benefits
assessment
before
it
finalizes
this
analysis.

Response:

The
benefits
analysis
completed
for
the
RIA
is
not
intended
to
model
local­
scale
changes
in
fish
tissue
concentrations
and
exposures
in
support
of
site­
specific
risk
analysis.
Instead,
modeling
conducted
for
the
RIA
is
intended
to
capture
generalized
regional
changes
in
methlmercury
exposure
resulting
from
reductions
in
power
plant
mercury
emissions
in
order
to
support
a
national­
scale
benefits
assessment
focusing
on
the
37
state
eastern
US
study
area.
For
additional
details
on
the
benefits
analysis
modeling
framework
see
Section
10
of
the
RIA.

EPA
recognizes
the
complexities
associated
with
methylation
of
mercury
deposited
in
waterbodies
and
watersheds
and
subsequent
biomagnification
within
the
aquatic
foodweb.
While
there
are
dynamic
fate/
transport
models
that
can
be
used
to
conduct
detailed
site­
specific
modeling
of
mercury
in
aquatic
and
terrestrial
environments
for
purposes
of
predicting
mercury
fish
tissue
concentrations
(
e.
g.,
the
dynamic
mercury
cycling
model),
it
is
not
feasible
to
utilize
these
resource­
intensive
models
for
a
regional­
or
nationals­
scale
analysis.
Therefore,
EPA
selected
the
MMAPs
models
for
application
in
the
RIA.
EPA
fully
recognizes
the
limitations
and
simplifying
assumptions
associated
with
this
model,
but
believes
that
it
has
sufficient
precision
to
support
a
benefits
analysis
conducted
at
the
regional­
or
national­
scale
(
i.
e.,
it
can
capture
general
trends
in
mercury
fish
tissue
response
to
changes
in
mercury
deposition
from
power
plants).
However,
to
provide
additional
perspective
on
the
relationship
between
mercury
deposition
and
fish
tissue
concentration
changes
(
especially
in
relation
to
MMAPS
linearity
assumption
and
the
lag
time
required
for
systems
to
reach
steady
state),
EPA
has
conducted
several
detailed
local­
scale
sensitivity
analyses.
The
results
of
these
case
studies
are
presented
and
discussed
in
Appendix
D.

The
RIA
includes
an
assessment,
to
the
extent
possible
given
our
scientific
understanding
9­
169
of
mercury
and
its
behavior
in
the
environment
and
impacts
on
human
health,
of
the
health
benefits
associated
with
the
proposed
regulatory
options.
Due
to
limitations
in
our
current
understanding
of
these
technical
areas
related
to
mercury
this
benefit
analysis
is
limited
to
the
self­
caught
freshwater
fish
consumption
pathway
and
to
IQ
deficits
in
prenatally­
exposed
infants.
In
keeping
with
precedent
in
evaluating
benefits
of
air
regulations
(
REFERENCE),
cobenefits
(
in
this
case
resulting
from
potential
reductions
in
direct
PM2.5)
are
also
included
in
the
RIA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
referenced
EPA's
Revised
Benefits
Methodology
Must
Account
Fully
for
the
Risks
and
Public­
Health
Costs
of
Hg
Pollution
EPA's
NODA
seeks
public
comment
on
a
suite
of
technical
issues,
supposedly
to
assist
the
agency
in
developing
its
final
assessment
of
the
benefits
of
Hg
control
pursuant
to
Executive
Order
12866.
Specifically,
EPA
asks
for
public
input
on
"
the
U.
S.
power
plant
contribution
to
total
Hg
deposition
within
the
U.
S.,"
the
agency's
planned
approach
to
"
evaluate
how
Hg
moves
through
the
atmosphere
and
how
it
ultimately
will
be
deposited,"
"
the
strengths
and
weaknesses
of
different
approaches
for
modeling
the
anticipated
response
offish
tissue
[
MeHg]
concentrations
to
declines
in
deposition,"
the
"
consumption
data"
to
be
used
in
EPA's
"
analysis
concerning
the
relationship
between
reductions
in
MeHg
concentrations
in
fish
tissue
and
reductions
of
human
exposure
to
MeHg,"
and
"
all
aspects
of
the
methodology
for
estimating
the
relationship
between
reductions
in
MeHg
exposure
and
improvements
in
health."

These
sweeping
requests
for
information
suggest
that
EPA
is
interested
in
more
than
simply
calculating
the
benefits
of
a
Hg
control
regime.
Instead,
the
agency
appears
to
be
giving
the
utility
industry
another
chance
to
advance
claims
that
power
plants
are
neither
a
significant
cause
of
U.
S.
Hg
deposition
nor
a
public
health
concern,
and
to
argue
that
EPA
should
weaken
its
proposed
Hg
rule
before
finalizing
it.
Indeed,
EPA
acknowledges
that
this
information
may
be
used
to
influence
the
stringency
of
the
final
rules,
saying:

"
To
the
extent
that
we
receive
any
comments
or
other
information
in
the
process
of
completing
the
benefits
assessment
for
purposes
of
EO12866
and
to
the
extent
that
such
information
bears
on
the
statutory
factors
relevant
to
setting
either
a
beyond­
the­
floor
standard
for
Hg
under
CAA
Section
112(
d)
or
a
standard
of
performance
for
Hg
under
CAA
Section
111,
we
intend
to
evaluate
and
consider
that
information
as
we
make
a
final
decision
as
to
which
regulatory
approach
to
pursue."

This
open­
ended
invitation
for
comment
reveals
how
far
EPA
has
veered
from
its
statutory
responsibilities
under
§
112
of
the
Act.
At
this
stage
of
the
rulemaking
process,
the
agency
should
be
refining
its
understanding
of
the
issues
central
to
the
development
of
a
proper
MACT
standard
by
correcting
the
problems
created
by
its
proposal
to
subcategorize
by
coal
rank,
by
abandoning
its
inflation
of
the
emission
standards
to
account
for
"
variability,"
by
making
an
unbiased
assessment
of
the
state
of
Hg
control
technology
in
light
of
manufacturers'
comments,
and
by
conducting
the
modeling
(
and
additional
technical
work)
necessary
to
evaluate
the
cost,
9­
170
energy
impacts,
and
non­
air
quality
impacts
of
numerous
above­
the­
floor
control
options.
Outrageously,
EPA
instead
seeks
to
revisit
issues
considered
four
years
ago
when
the
agency
concluded
that
regulating
power
plants'
hazardous
air
emissions
was
"
appropriate
and
necessary,"
and
gives
the
public
a
mere
month
to
make
 
again
 
the
scientific
case
for
stringent
controls
on
utility
units.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
Chapters
10
and
11
of
the
CAMR
Regulatory
Impact
Analysis
for
a
discussion
of
the
exposure
modeling
and
benefit
methodologies
used
to
analyze
the
benefits
associated
with
this
rulemaking.

1.
Step
1:
Analyzing
Hg
Emissions
from
Other
Sources.
EPA
plans
to
do
fate
and
transport
modeling
of
emissions
originating
in
other
countries
to
allow
an
estimated
of
U.
S.
power
plant
contribution
to
total
Hg
deposition
in
the
U.
S.
EPP
received
comments
relevant
to
this
issue
from
the
Center
for
Energy
and
Economic
Development
(
OAR­
2002­
0056­
2256),
Electric
Power
Research
Institute
(
OAR­
2002­
0056­
2578),
Hubbard
Brook
Research
Foundation
(
OAR­
2002­
0056­
2038),
National
Mining
Association
(
OAR­
2002­
0056­
2434),
TXU
Energy
(
OAR­
2002­
0056­
1831),
and
Utility
Air
Regulatory
Group
(
OAR­
2002­
0056­
2922).
Some
of
these
comments
used
different
approaches
for
stimulating
boundary
conditions
for
apportioning
Hg
exposure
from
domestic
and
international
sources,
and
EPA
asks
for
input
on
these
alternative
approaches
and
analyses.

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
noted
that
EPA
requested
that
stakeholders
identify
sources
of
Hg
emissions
other
than
coal
fired
utilities
for
inclusion
into
the
IPM.
The
lack
of
Hg
source
data
in
the
1999
National
Emission
Inventory
(
NEI)
is
a
direct
result
of
the
Agency's
decision
not
to
include
hazardous
air
pollutants
in
its
Consolidated
Emission
Reporting
Rule.
Other
source
categories
not
regulated
for
Hg
emissions
include
sewage
sludge
incineration
and
Portland
cement
plants
that
burn
coal.
Of
combustion
sources,
coal
fired
utilities
make
up
half
the
Hg
emitted
in
New
York
State.
The
Department
has
promulgated
and
implemented
more
stringent
state
regulations
that
contain
stricter
emission
limits
for
Hg
emissions
for
the
municipal
waste
combustion
source
category
than
promulgated
by
the
EPA.
The
current
estimated
Hg
emissions
inventory
for
stationary
sources
in
New
York
is
attached
as
Table
1
(
see
OAR­
2002­
0056­
5458).
The
Department
is
evaluating
other
source
categories
for
reductions
and
hopes
that
EPA
will
propose
a
NESHAP
for
the
utility
sector
that
will
provide
meaningful
reductions
of
national
Hg
emissions.

Resources:

EPA
appreciates
the
additional
information
submitted
by
the
commenter.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
Chapter
8
of
the
CAMR
9­
171
Regulatory
Impact
Analysis
for
a
discussion
of
the
air
quality
modeling
for
the
CAMR
regulatory
options
and
the
resulting
change
in
mercury
deposition.

Comment:

One
commenter
(
OAR­
2002­
0056­
5488)
stated
that
studies
from
the
Florida
Everglades
and
Wisconsin,
as
well
as
the
heterogeneity
among
the
states
in
Hg
deposition
highlight
the
localized
nature
of
Hg
deposition.
Any
benefits
estimation
must
model
local
deposition,
methylation,
and
the
consumption
of
fish
contaminated
by
such
local
deposition,
whether
that
consumption
occurs
locally
or
more
nationally.
The
NODA
refers
to
the
EPA's
intent
"
to
estimate
the
U.
S.
power
plant
contribution
to
total
Hg
deposition
within
the
U.
S."
From
a
public
health
perspective,
this
estimate
is
meaningless,
as
Hg
deposition,
methylation,
and
human
exposure
from
U.
S.
coal­
fired
power
plants
depend
on
highly
localized
conditions
and
are
unrelated
to
the
U.
S.
fraction
of
total
Hg
deposition
averaged
over
the
entire
U.
S.
land
mass.

Response:

Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling
and
Chapters
11
for
a
benefits
analysis
of
the
CAMR.
Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
presented
several
specific
issues
below
that
would
benefit
from
such
careful
peer
review.
They
did
not
intend
this
list
to
be
comprehensive,
but
merely
included
it
to
illustrate
that
the
agency
must
address
critical
scientific
issues
prior
to
making
changes
to
its
deposition
and
watershed
models
or
conducting
other
components
of
the
proposed
analyses.
This
overview
serves
to
demonstrate
that
it
would
be
foolish
to
hold
up
final
Hg
regulations
while
EPA
further
investigates
certain
technical
issues
concerning
the
emissions,
fate,
and
toxicity
of
Hg
from
power
plants.

°
Global
model
of
Hg
transport.
The
global
model
of
Hg
transport
developed
by
the
Electric
Power
Research
Institute
needs
thorough
vetting
by
the
broader
scientific
community
before
it,
or
results
generated
by
it,
are
adopted
by
the
EPA.
In
particular,
the
spatial
resolution
of
EPRI's
model
is
coarse
and
the
effect
of
that
resolution
profoundly
affects
the
modeling
results.

Response:

EPA
appreciates
the
commenters
input.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
Chapter
8
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
the
air
quality
modeling
used
to
analyze
the
CAMR
rule.

Comment:
9­
172
One
commenter
(
OAR­
2002­
0056­
5423)
notes
that
natural
sources
of
Hg
emissions
dominate
the
small
amount
of
Hg
emissions
from
U.
S.
power
plants.
This
commenter
believes
that
this
fact
brings
into
stark
reality
that
any
meaningful
control
of
Hg
emissions
toward
a
realistic
"
reduction"
in
Hg
deposited
on
U.
S.
soils
will
be
almost
impossible.
There
are
well
over
5,000
surface
and
submarine
volcanoes
in
the
world,
with
about
50
to
60
eruptions
each
month,
according
to
the
Smithsonian
Institution.
Volcanic
degassing
may
be
the
single
largest
source
of
ocean
and
atmospheric
Hg.
For
example,
at
Roaming
Mountain,
Wyoming,
researchers
measured
Hg
emanating
from
the
clay
hillside
at
up
to
2,400
nanograms
per
square
meter
per
hour.
By
comparison,
background
levels
away
from
geothermal
areas
range
from
zero
to
ten.
So
Hg
emissions
from
active
geothermal
areas
could
be
tens
and
hundreds
times
more
than
from
other
background
areas.

For
obvious
reasons,
volcanic
degassing
and
other
geothermal
activities
as
dominant
sources
of
Hg
have
not
received
much
attention
or
have
been
downplayed.
For
example,
EPA
staff
provided
the
Administrator
with
an
outdated
volcanic
accounting
study.
Figure
A1
(
see
OAR­
2002­
0056­
5423)
clearly
shows
that
EPA's
current
adopted
value
for
the
annual
contribution
of
atmospheric
Hg
by
volcanic
eruptions
and
degassing
is
significantly
under
accounted
for
by
about
a
factor
of
6
to
7.
When
adjusted
to
reflect
a
more
accurate
accounting
of
volcanic
Hg
emission
(
Figure
A2,
see
OAR­
2002­
0056­
5423),
U.
S.
power
plant
contributions
to
the
annual
estimated
Hg
budget
world­
wide
fall
to
an
insignificant
0.8
percent
or
less.

Figure
A3
(
see
OAR­
2002­
0056­
5423)
maps
the
range
of
potential
volcanic
activity
in
the
Western
U.
S.
These
are
also
potential
sources
of
enormous
Hg
degassing
and
deposition,
especially
Yellowstone
National
Park.

Figure
A4
(
see
OAR­
2002­
0056­
5423)
emphasizes
that
the
pools
of
Hg
stored
in
U.
S.
forests
and
peat
lands
(
covering
less
than
2
percent
of
U.
S.
area)
swamp
the
100­
150
tons
total
annual
anthropogenic
Hg
emission
from
U.
S.
sources.

Taken
together,
these
figures
support
EPA's
admission
of
poor
accounting
for
(
a)
natural
sources
of
Hg
emission
and
(
b)
the
large
pool
of
background
Hg
at
all
times
available
for
emission
from
the
natural
ecosystems
and
geological
settings
within
the
U.
S.

Yellowstone
National
Park
is
just
one
such
geological
reservoir
of
Hg.
A
report
issued
last
fall
by
the
Idaho
National
Engineering
and
Environmental
Lab
showed
that
several
places
in
Yellowstone
Park
have
higher
levels
of
airborne
Hg
than
power
plants.
It
went
on
to
say
that
Yellowstone
could
emit
or
exceed
as
much
Hg
as
all
of
Wyoming's
eight
coal­
fired
power
plants
combined.

At
Yellowstone
Lake,
researchers
have
discovered
submerged
faults,
explosion
craters,
domal
features,
hydrothermal
vents,
lava
flows
extending
far
out
into
the
lake
and
much
more.
Mercury
may
propagate
from
these
natural
features
up
through
the
food
chain
transforming
into
MeHg
in
native
cutthroat
trout.

And
since
Yellowstone
is
the
headwaters
of
important
tributaries
to
the
Missouri
9­
173
(
Yellowstone
River)
and
Columbia
(
Snake
River),
no
one
knows
how
far
the
natural
contamination
carries
through
the
Earth's
air
and
water
systems.

However,
the
Hg
presence
and
emissions
were
noted
by
experts
to
pose
no
danger
to
park
rangers
or
visitors.
Even
native
grizzly
bears
who
consume
up
to
400
lb
of
spawning
cutthroat
trout
exhibit
no
ill
effects,
according
to
researchers
with
the
Interagency
Grizzly
Bear
Study
Team.

Thus,
the
most
important
question
for
EPA's
Hg
emission
and
deposition
modeling
team
to
answer
confidently
is
whether
the
proposed
CAMR
to
control
Hg
emissions
from
U.
S.
power
plants
can
assure
any
consequential
"
reduction"
of
Hg
deposition
in
U.
S.
soils,
leading
to
any
reputed
public
health
"
benefits."

Response:

Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling
and
Chapters
11
for
a
benefits
analysis
of
the
CAMR.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
provides
an
important
challenge
for
EPA's
Hg
emission
and
deposition
modeling
team
(
Figure
B1,
see
OAR­
2002­
0056­
5423).
It
shows
the
results
from
recent
measurements
of
Hg
content
in
Illinois
soils
clearly
suggesting
that
atmospheric
deposition
from
any
past
or
current
U.
S.
power
plants
is
insignificant
compared
to
the
large
quantity
of
background
Hg
already
resided
in
soils
across
the
state.
This
is
why
it
is
extremely
difficult
for
EPA
to
convincingly
show
that
the
Hg
from
U.
S.
power
plant
emissions
will
be
selectively
filtered
by
the
ecosystem
components
in
Illinois
(
or
anywhere
else)
to
bring
about
increased
levels
of
MeHg
in
freshwater
fish
while
ignoring
the
large
pool
of
natural
Hg
in
the
native
ecosystem.
It
is
therefore
extremely
difficult,
if
not
impossible,
for
EPA
to
plausibly
demonstrate
the
assertion
that
its
proposed
CAMR
can/
will
bring
about
any
direct,
measurable
improvement
in
public
health.

In
Figure
B2
(
see
OAR­
2002­
0056­
5423),
the
commenter
provides
a
recent
Hg
emission
and
deposition
budget
analysis
for
the
northeastern
Chinese
city
of
Changchun.
Scientists
found
that
of
that
7.1
tons
of
Hg
emitted
by
the
city
of
Changchun,
only
less
than
12
percent
of
coal­
fired
power
plant
Hg
was
deposited
back
into
the
local
area,
while
most
escaped
as
contributions
to
regional
and
global
cycling
of
Hg.

This
scenario
of
the
local
Hg
emission
and
deposition
budget
at
Changchun,
China
may
serve
as
a
useful
model
verification
target
for
the
EPA's
Hg
emission
and
deposition
modeling
team
under
a
wide
range
of
meteorological
and
climatic
conditions
and
settings.
9­
174
Man­
made
atmospheric
deposition
of
Hg
is
a
very
small
contributor
to
the
huge
amount
of
natural
Hg
in
Illinois
and
U.
S.
soils
(
1)
It
has
been
estimated
that
"
anthropogenic
activities
could
have
increased
world
soil
Hg
content
by
[
only]
0.02
percent."

(
2)
From
the
measured
high
Hg
content
in
Illinois
soils,
it
would
take
9000
years
at
the
currently
measured
atmospheric
deposition
rate
to
dump
all
the
Hg
to
the
top
380­
cm
of
Illinois
soils.

(
3)
If
assuming
the
average
Hg
in
the
top
140­
cm
of
U.
S.
soils
to
be
about
10
ppb,
it
would
take
14,000
years
at
the
current
atmospheric
deposition
rate
to
do
it.

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling.
Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
presents
an
important
observational
target
for
EPA's
modelers
(
Figure
C1,
see
OAR­
2002­
0056­
5423).
First,
it
is
important
to
point
out
that
the
Hg
in
rainwater
or
moist
air
exists
mostly
in
the
dissolved
ionic
form
of
Hg
(
Hg2+)
rather
than
MeHg
 
the
biologically
active
form
of
Hg
that
may
affect
human
health
at
extraordinary
dose
levels.
Figure
C1
(
see
OAR­
2002­
0056­
5423)
shows
that
most
(
72.5
percent)
of
the
MeHg
in
the
Chesapeake
Bay
ecosystems
comes
from
in­
situ
production.
Remote
transport
of
MeHg
from
rivers
contributes
about
another
20
percent,
and
atmospheric
deposition
sources
may
contribute
toward
production
of
as
little
as
7.5
percent
of
MeHg
in
the
Chesapeake
Bay's
ecosystems.
Such
a
scenario
of
the
MeHg
budget
clearly
emphasizes
the
need
for
better
scientific
understanding
of
the
complex
physical,
chemical
and
biological
factors
controlling
the
production
and
destruction
of
MeHg,
and
why
the
levels
of
MeHg
in
an
ecosystem
do
not
depend
directly
on
available
amounts
of
inorganic
Hg
(
i.
e.,
from
background
or
power
plant
emissions).

Sources
of
MeHg
in
the
Chesapeake
Bay:
Atmospheric
deposition
is
a
not
an
important
contributor
Percentage
contribution
of
70
percent
MeHg
sources
60
percent
in
the
Chesapeake
Bay
In­
situ
Production
Rivers
Atmospheric
Deposition
Reference:
Mason
et
al.
(
1999)

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling.
9­
175
Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
UARG,
following
EPRI,
argues
that
Hg
pollution
is
a
global
problem
and,
therefore,
EPA
should
not
regulate
Hg
emissions
pursuant
to
Section
112.
See
UARG
Comments
at
25­
26.
The
commenter
noted
that,
in
particular,
UARG
contends
that
only
25
percent
of
domestic
Hg
deposition
stems
from
domestic
anthropogenic
sources.
Id.
(
citing
EPRI
Comments
at
13).
But
little,
the
commenter
stated,
if
any,
basis
exists
to
have
confidence
in
UARG's
estimates
given
EPA's
conclusion
that
Hg's
fate
in
the
environment
can
not
be
tracked
with
precision
and
that
Hg
emitted
from
any
source
may
be
re­
emitted
into
the
environment.
See
69
Fed.
Reg.
4652,
4658
(
Jan.
30,
2004).
The
commenter
stated
that
indeed,
UARG
itself
contends
that
"
the
state­
of­
the­
science
on
Hg
cycling
is
too
imprecise
to
predict"
the
consequences
of
changes
in
Hg
deposition.
UARG
Comments
at
26
n.
57.

The
commenter
stated
that,
more
importantly,
even
if
UARG
is
correct
that
Hg
is
a
global
problem,
it
does
not
follow
that
EPA
should
not
regulate
domestic
power
plant
emissions
pursuant
to
section
112.
The
commenter
further
stated
that
to
the
contrary,
the
Court
of
Appeals
for
the
D.
C.
Circuit
has
already
made
clear
that
whether
a
pollutant
has
local,
regional
or
global
consequences
is
not,
standing
alone,
a
sufficient
legal
basis
for
concluding
that
the
pollutant
should
not
be
regulated.
See
American
Lung
Ass'n,
134
F.
3d
at
392
(
rejecting
EPA's
argument
that
it
could
avoid
revising
a
national
ambient
air
quality
standard
simply
by
claiming
that
the
pollutant
at
issue
had
local
effects
only).
The
commenter
added
that
simply
because
EPA
cannot
prevent
Hg
from
entering
the
U.
S.
from
other
countries
is
not
a
reason
for
EPA
to
avoid
regulating
domestic
Hg
emissions.
The
commenter
stated
that
UARG's
argument
that
local
emissions
should
be
exempt
from
regulation
because
they
cause
only
part
of
the
problem
makes
no
sense:
Just
because
pollution
enters
our
borders
from
somewhere
else
is
not
a
reason
to
allow
domestic
sources
to
create
even
more
pollution.
The
commenter
further
stated
that,
indeed,
it
is
well­
established
that
a
polluter
may
be
enjoined
from
contributing
to
a
public
nuisance
even
where
the
polluter's
contributions
alone
are
insufficient
to
create
the
nuisance.
See,
e.
g.,
The
Law
of
Torts
§
52
("
Pollution
of
a
stream
to
even
a
slight
extent
becomes
unreasonable
when
similar
pollution
by
others
makes
the
condition
of
the
stream
approach
the
danger
point.");
Cox
v.
City
of
Dallas,
256
F.
3d
281,292
n.
19
(
5th
Cir.
2001)
(
explaining
that
nuisance
liability
attaches
where
one
simply
contributes
to
the
nuisance);
City
of
New
York
v.
Beretta
U.
S.
A.
Corp.,
315
F.
Supp.
2d
256,
282
(
E.
D.
N.
Y.
2004)
("
Where
it
is
difficult
or
impossible
to
separate
the
injury
caused
by
one
contributing
actor
from
that
caused
by
another
and
where
each
contributing
actor's
responsibility
individually
does
not
constitute
a
substantial
interference
with
a
public
right,
defendants
may
still
be
found
liable
for
conduct
creating
in
the
aggregate
a
public
nuisance
if
the
suit
is
one
for
injunctive
relief").

The
commenter
stated
that
at
bottom,
EPRI
and
UARG
appear
to
be
arguing
that
EPA
needs
greater
proof
that
power
plant
Hg
emissions
cause
harm
before
it
can
regulate
those
emissions.
But,
the
commenter
stated,
no
reason
exists
for
EPA
to
allow
harm
from
Hg
emissions
to
continue
until
it
has
yet
more
concrete
proof
of
that
harm.
The
commenter
further
stated
that
to
the
contrary,
existing
science
already
confirms
the
harm
is
sufficient
for
EPA
to
act.
The
9­
176
commenter
stated
that,
finally,
given
the
overarching
flaws
in
EPRI's
and
UARG's
comments,
EPA
should
look
with
skepticism
upon
their
more
detailed
technical
claims.

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
any
emissions
inventory
must
do
a
good
job
of
defining
the
global
sources
of
Hg
emissions.
Recent
modeling
by
EPRI
and
others
has
revealed
that
a
substantial
majority
of
Hg
that
is
deposited
in
the
U.
S.
(
about
75
percent)
originates
from
natural
sources
and
anthropogenic
sources
outside
the
U.
S.
Asian
sources
may
provide
20
percent
of
the
Hg
deposited
in
the
U.
S.
EPRI's
NODA
comments
(
see
OAR­
2002­
0056­
5469)
offer
a
number
of
sources
of
information
on
global
Hg
emissions.

Modeling
of
Hg
emissions
from
global
and
domestic
sources
remains
a
challenging
exercise.
To
date,
Hg
model
results
have
not
matched
the
levels
of
Hg
in
water
bodies
and
fish
in
various
parts
of
the
U.
S.
The
atmospheric
chemistry
of
Hg
may
hold
the
key
to
this
disparity.
As
EPRI
notes
in
its
NODA
comments,
atmospheric
Hg
reactions
can
move
in
different
directions.
For
major
urban
sources,
including
mobile
sources,
elemental
Hg
can
be
rapidly
oxidized
to
ionic
Hg
which
can
then
be
removed
form
the
atmosphere
by
wet
and
dry
processes.
By
contrast,
ionic
Hg
emitted
from
coal­
fired
power
plants
appears
to
be
reduced
to
elemental
Hg
shortly
after
leaving
the
stack.
Recent
results
from
Edgerton
suggest
that
models
that
do
not
account
for
this
atmospheric
reduction
of
ionic
Hg
will
over
predict
the
local
and
regional
Hg
deposition
from
coal­
fired
power
plants.

Future
EPA
modeling
should
use
the
results
of
global
modeling
to
define
the
boundary
conditions
for
domestic
modeling.
Global
modeling
is
a
better
scientific
approach
for
setting
boundary
conditions
than
arbitrarily
setting
those
conditions.
If
EPA
uses
the
results
of
global
modeling
to
set
boundary
conditions,
it
should
still
review
those
results
to
ensure
they
are
reasonable.

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling.
9­
177
2.
Step
2:
Analyzing
Air
Dispersion
Modeling
Capabilities.
EPA
plans
on
modeling
the
atmospheric
dispersion,
atmospheric
speciation,
and
deposition
of
Hg
using
the
REMSAD
and
CMAQ
models,
with
the
GEOS­
CHEM
global
model
for
boundary
conditions
input.
The
simulated
results
will
be
compared
with
ambient
monitoring
data
from
the
Mercury
Deposition
Network
(
MDN).
EPA
requested
comments
on
the
use
of
these
models
and
approach.
EPA
received
comments
on
the
use
of
models
for
assessing
the
impacts
of
the
proposed
programs
on
Hg
deposition
patterns
from
the
Center
for
Energy
and
Economic
Development
(
OAR­
2002­
0056­
2256),
Clean
Air
Task
Force
et
al
(
OAR­
2002­
0056­
3460),
Electric
Power
Research
Institute
(
OAR­
2002­
0056­
2578),
and
Utility
Air
Regulatory
Group
(
OAR­
2002­
0056­
2922).
EPA
also
sought
comment
on
the
alternative
approaches
suggested
by
some
of
these
commenters.

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
highlighted
another
concern
related
to
EPA's
proposed
rule,
which
is
the
issue
of
hot
spots.
The
commenter
believed
the
definition
of
a
"
hot
spot"
in
the
proposal
is
insufficient.
The
proposal
states,
"
a
power
plant
may
lead
to
a
hot
spot
if
the
contribution
of
the
plant's
emissions
of
Hg
to
local
deposition
is
sufficient
to
cause
blood
Hg
levels
of
highly
exposed
individuals
near
the
plant
to
exceed
the
RID"
(
69
Federal
Register
4702).
The
commenter
was
very
concerned
that
the
proposal
considers
the
effects
of
only
one
plant
at
a
time
in
determining
if
there
is
a
hot
spot.
This
method
of
determining
hot­
spots
ignores
the
cumulative,
localized
impacts
of
Hg
deposition
caused
by
multiple,
nearby
or
co­
located,
coal­
fired
utility
boilers
by
individually
quantifying
and
analyzing
the
air
quality
impact
of
each
boiler
in
the
absence
of
the
others.
This
is
contrary
to
previously
adopted,
long­
standing,
peer­
reviewed
EPA
procedures
for
performing
air
quality
modeling
on
stationary
sources
for
criteria
pollutants
and
is
not
acceptable
for
performing
air
quality
modeling
for
more
hazardous
pollutants
like
Hg.

The
commenter
had
an
additional
concern
related
to
the
improvement
of
existing
hot
spots
and
stated
that
45
states
have
issued
fish
consumption
advisories
due
to
Hg.
Clearly
a
contaminated
water
body
is
a
hot
spot
that
already
exists.
In
fact,
the
current
situation
indicates
that
we
have
"
hot
states"
and
"
hot
regions"
and
not
just
localized
hot
spots.
The
commenter
feared
that
EPA's
proposal,
which
calls
for
a
nationwide
market­
based
cap­
and­
trade
program,
will
not
ameliorate
the
problem
of
existing
hot
spots
or
areas.

The
commenter
categorically
disagreed
with
UARG's
position
and
strongly
urged
EPA,
if
the
agency
decides
to
proceed
with
a
rule
under
Section
111,
to
maintain
the
ability
of
state
and
local
agencies
to
opt
out
of
the
trading
program.

The
Clean
Air
Act
explicitly
allows
state
and
local
air
pollution
control
agencies
to
adopt
programs
more
stringent
than
those
of
the
federal
government.
Specifically,
section
116
states
that
air
quality
agencies
are
not
precluded
from
adopting
or
enforcing
any
standards,
limitations
or
requirements
as
long
as
they
are
at
least
as
stringent
as
those
required
under
the
federal
program.
9­
178
The
only
exceptions
are
found
in
section
119
of
the
Clean
Air
Act,
which
preempts
certain
state
and
local
regulation
of
mobile
sources.
Therefore,
UARG's
suggested
approach,
in
which
EPA
would
preempt
state
and
local
agencies'
ability
to
adopt
a
more
stringent
program
that
does
not
permit
trading,
is
in
direct
conflict
with
section
116
of
the
Clean
Air
Act.

The
commenter
stated
that
for
a
variety
of
reasons,
maintaining
the
ability
of
state
and
local
agencies
to
adopt
more
stringent
programs
is
essential.
Not
the
least
of
these
reasons
is
that
state
and
local
agencies
will
need
some
way
of
addressing
and
preventing
hot
spots
in
their
areas.
In
fact,
EPA
appropriately
acknowledged
this
in
its
January
30,
2004,
proposal
by
stating,
"[
s]
tates
retain
the
power
under
the
proposed
section
111
rule
to
adopt
stricter
regulations
to
address
local
hot
spots
or
other
problems"
(
69
Federal
Register
4702).

UARG
expresses
concern
in
its
comments
that
allowing
states
to
opt
out
of
the
program
would
result
in
a
"
patchwork
approach".
The
commenter
contended
that
a
federal
standard,
such
as
what
EPA
has
proposed,
that
is
less
stringent
than
the
law
requires
would
be
to
blame
for
any
patchwork
effect.
In
fact,
state
and
local
agencies
have
already
begun
to
adopt
their
own
programs
to
ensure
adequate
public
health
protection
in
their
states
(
see
attached
table).
If
EPA
and
industry
wish
there
to
be
more
national
consistency,
EPA
can
accomplish
this
by
adopting
a
protective
standard
consistent
with
the
requirements
of
Section
112(
d).
Fewer
state
and
local
agencies
may
then
feel
compelled
to
adopt
different
approaches
(
see
OAR­
2002­
0056­
5464).

Response:

EPA
has
examined
the
commenter's
concerns
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
has
addressed
the
hot
spots
issue
in
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112
Notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5559),
beginning
in
2001,
began
a
two­
year
effort
to
develop
a
Hg
atmospheric
modeling
system
for
Wisconsin
and
the
Great
Lakes
region.
Partial
funding
for
this
work
was
provided
by
a
grant,
#
X97599601,
from
EPA.

Based
on
this
experience,
the
commenter
had
the
following
comments
on
the
modeling
of
Hg
deposition
that
EPA
is
proposing
to
conduct
as
part
of
the
revised
benefits
assessment.

Step
1
 
Analyzing
Mercury
Emissions
from
Other
Sources.
The
commenter
used
1999
National
Emission
Inventory
(
NEI)
to
build
emissions
estimates
for
Hg
and
conducted
considerable
quality
assurance
of
the
Hg
emissions
data.
Based
on
experience
with
the
1999
NEI
9­
179
Hg
emissions
data,
if
EPA
chooses
to
use
the
2002
NEI
data,
this
commenter
recommends
that
EPA
conduct
considerable
quality
assurance
of
these
data,
before
they
are
used
in
model
simulations.

In
simulations,
the
commenter
added
Canadian
and
Mexican
emission
sources.
Although
those
data
are
somewhat
incomplete,
the
commenter
would
be
happy
to
share
these
data
with
EPA.

Step
2
 
Analyzing
Air
Dispersion
Modeling
Capability.
There
is
a
significant
amount
of
uncertainty
associated
with
the
simulation
of
Hg
deposition.
EPA
should
conduct
an
uncertainty
analysis
with
the
modeling
system
to
evaluate
the
effect
on
the
modeling
simulations
for
changes
to
the
underlining
assumptions
in
the
model.
In
particular,
EPA
should
evaluate
changes
to
the
wet
deposition
algorithms,
dry
deposition
algorithms
and
emissions
speciation
profiles
and
processes
that
form
MeHg
in
water
bodies.

There
is
some
anecdotal
evidence
such
as
around
the
White
Pine
smelter
in
Michigan
and
around
certain
Florida
point
sources,
that
reductions
in
Hg
emissions
at
large
sources
results
in
a
reduction
in
Hg
concentration
in
nearby
water
bodies.
To
date,
this
phenomenon
has
not
been
satisfactorily
simulated
with
Eulerian
grid
models.
EPA
should
further
investigate
this
phenomenon,
since
it
seems
to
highlight
a
significant
problem
with
the
current
state
of
the
science
Hg
modeling
systems
and
puts
into
doubt
the
interpretation
of
the
results
of
model
simulations.
If
a
significant
improvement
in
nearby
water
quality
results
from
a
reduction
in
Hg
emissions,
this
commenter
will
realize
a
much
greater
benefit
from
power
plant
Hg
reductions
than
has
been
demonstrated
by
previous
model
simulations.

EPA
should
reconsider
its
selection
of
the
Regional
Modeling
System
for
Aerosols
and
Deposition
(
REMSAD)
for
one
of
the
models
to
use
in
its
analyses.
Under
a
grant,
AER
and
Environ
worked
with
the
commenter
to
create
a
version
of
the
Comprehensive
Air
Quality
Model
with
extensions
(
CAMx)
that
includes
the
most
up­
to­
date
Hg
chemistry
and
deposition
algorithms.
The
model
development
and
simulations
were
peer
reviewed
by
Alpine
Geophysics.
When
measured
wet
deposition
at
Mercury
Deposition
Network
(
MDN)
sites
was
compared
with
model
results,
the
commenter
found
that
CAMx
provided
much
better
model
performance
than
REMSAD.

Deposition
is
very
sensitive
to
rainfall
simulation
in
MM5.
Since,
in
the
eastern
U.
S.,
a
significant
portion
of
annual
Hg
wet
deposition
occurs
in
convective
rain
events,
it
is
important
to
properly
simulate
convection
in
the
meteorological
model.
In
model
performance
testing
for
MM5,
the
commenter
found
that
using
a
12
Km
grid
spacing
rather
than
36
Km,
46
vertical
layers
rather
than
34,
and
the
Reisner
Graupel
Ice
scheme
rather
than
Simple
Ice
provided
superior
performance
for
a
convective
rainfall
event
in
the
Great
Lakes
area.
These
changes
will
adversely
affect
model
run
time,
but
may
be
worth
employing
for
comparison
purposes.

Response:

Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
9­
180
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling.

Comment:

The
commenter
(
OAR­
2002­
0056­
5563)
wished
to
specifically
address
the
issue
of
utilizing
modeling
under
the
notice
of
data
availability
for
the
Clean
Air
Mercury
Rule.
The
commenter
felt
that
modeling
should
only
compliment
a
comprehensive
monitoring
program
of
Hg
pollution.
Monitoring
should
not
be
limited
to
the
Great
Lakes
and
Eastern
portion
of
the
country­
it
should
be
extended
to
all
parts
of
the
U.
S.,
especially
to
tribal
lands
and
communities.
The
utilization
of
the
Community
Multiscale
Air
Quality
(
CMAQ)
and
Regional
Modeling
System
for
Aerosols
and
Deposition
(
REMSAD)
models
that
the
EPA
had
used
and
intended
to
use
in
the
future
for
modeling
the
atmospheric
dispersion,
speciation,
and
deposition
of
Hg
did
not
address
tribal
concerns
effectively.
The
EPA's
plan
was
to
use
a
36­
kilometer
modeling
grid
for
both
CMAQ
and
REMSAD
in
assessing
the
aforementioned
items.
However,
these
models
were
equipped
to
handle
12
and
4­
kilometer
modeling
grids.
In
order
to
assess
the
real
effects
of
Hg
on
tribal
lands,
the
commenter
urged
the
EPA
to
utilize
the
latter
modeling
grids.
This
rational
was
related
to
the
size
of
tribal
lands
and
communities.
Most
tribes
occupied
land
closer
to
these
grid
sizes.
Furthermore,
the
proportion
of
the
proposed
models
for
both
CMAQ
and
REMSAD
models
failed
to
distinguish
between
different
jurisdictions
such
as
tribal,
state,
and
county
lands.
This
issue
failed
in
carrying
out
the
trust
responsibility
of
the
federal
government.
Tribal
lands,
as
sovereign
Nations,
had
the
right
to
be
indicated
as
such
in
modeling
practices.
In
addition,
the
NTAA
also
feels
that
proposed
modeling
techniques
will
error
in
properly
addressing
jurisdictional
point
sources
of
Hg.
Therefore,
modeling
output
could
be
adversely
affected.

Response:

Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling
and
Chapters
11
for
a
benefits
analysis
of
the
CAMR.

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
agreed
with
the
subcategorization
of
coal
types
for
regulatory
purposes
in
response
to
the
NODA
section
II.
C.
3.
b.,
but
disagrees
with
the
standard
(
or
average)
speciation
profile
in
modeling
analysis.
Work
conducted
by
the
Department
on
the
1999
Information
Collection
Request
(
ICR)
shows
that
the
majority
of
Hg
emitted
in
the
eastern
half
of
the
US
is
predominantly
in
the
oxidized
form.
The
speciation
profile
cited
in
the
NODA,
54
percent
elemental,
and
43
percent
oxidized
and
3
percent
particulate
Hg,
is
a
national
average
and
does
not
represent
the
Northeast
States
potential
deposited
burden.
The
Department's
analysis
of
the
ICR
data
indicates
a
profile
closer
to
30
percent
elemental,
65
percent
oxidized
and
5
percent
particulate
Hg
for
sources
which
are
impacting
New
York.
9­
181
The
NODA
focuses
on
industry
sponsored
research
about
the
speciation
of
atmospheric
Hg
after
it
exits
the
stack
and
how
emissions
rapidly
converted
to
elemental
Hg
in
the
plume
will
not
be
deposited
in
the
U.
S.
due
to
their
long
atmospheric
residence
time
(
Air
Docket
OAR­
2002­
0056­
2928
and
OAR­
2002­
0056­
2848).
This
entire
data
set
was
not
included
in
the
docket
and
the
Department
could
not
locate
any
information
which
indicates
the
data
had
undergone
any
public
and
peer
review.
The
EPA
must
cautiously
evaluate
the
results
and
conclusions
drawn
from
this
research
in
light
of
the
unknown
and
non­
linear
relationship
between
Hg
emissions
and
deposition.
There
are
many
factors
which
need
to
be
assessed
when
evaluating
atmospheric
Hg
transformation
and
potential
deposition
scenarios.
The
NODA
must
consider
the
emerging
science
about
the
atmospheric
chemistry
and
deposition
of
Hg.
These
recent
findings
indicate
that
the
abundance
of
oxidized
Hg
increases
with
altitude
in
the
troposphere,
and
airborne
halogens
and
oxidants,
such
as
ozone
facilitate
the
oxidation
of
elemental
Hg,
which
in
turn
increases
both
wet
and
dry
deposition
of
Hg.
The
reactions
are
occurring
in
areas
with
high
seasonal
ozone
levels
and
also
appear
to
take
place
in
the
temperate
coastal
zone.
Researchers
have
concluded
that
a
short
half­
life
for
elemental
Hg
is
probable.

Response:

EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.
Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.

Comment:

One
commenter
(
OAR­
2002­
0056­
5425)
said
their
comments
were
specific
to
the
Community
Multiscale
Air
Quality
(
CMAQ)
and
Regional
Modeling
System
for
Aerosols
and
Deposition
(
REMSAD)
models
that
the
EPA
has
used
and
intends
to
use
in
the
future
for
modeling
the
atmospheric
dispersion,
speciation,
and
deposition
of
Hg.
The
EPA
is
planning
to
use
36
kilometer
modeling
grids
for
both
CMAQ
and
REMSAD
in
assessing
the
aforementioned
items
although
these
same
models
are
equipped
to
handle
12
and
4
kilometer
modeling
grids.
In
the
interest
of
assessing
the
true
effects
of
Hg
dispersion,
speciation
and
deposition
on
tribal
lands,
the
EPA
should
use
the
latter
modeling
grids
because
most
tribes
occupy
lands
closer
to
these
grid
sizes
as
opposed
to
the
former
grid
size
being
proposed
by
the
EPA
for
modeling.
Furthermore,
the
spatial
resolution
of
the
gridded
output
for
both
the
CMAQ
and
REMSAD
models
fails
to
distinguish
between
different
jurisdictions
such
as
tribal,
state
and
county
lands.
Such
a
failure
could
likely
cause
the
models
to
incorrectly
attribute
(
e.
g.,
mislocate)
one
jurisdiction's
Hg
point
source
to
another
jurisdiction
(
such
as
a
tribe's
land).
This
incorrect
attribution
of
a
point
source
could
then
adversely
affect
the
results
of
the
modeling
output.
A
means
for
mitigating
this
problem
is
to
assign
a
numeric
code
to
the
jurisdiction
within
the
grid
9­
182
cell
having
the
dominant
contribution
to
emissions
in
that
cell.
This
would
help
the
models
to
produce
more
accurate
results
otherwise
impossible
under
current
model
designs.

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
8
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
EPA's
air
quality
modeling
analysis.
Please
also
see
EPA's
Technical
Support
Document
for
the
Final
Clean
Air
Mercury
Rule:
Air
Quality
Modeling.

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
research
results
reported
to
U.
S.
EPA
in
June
2004
analyzed
Hg
deposition
for
a
2004
Base
Case
emissions
inventory
and
two
2020
scenarios,
the
proposed
Maximum
Achievable
Control
Technology
(
MACT)
rule
and
the
proposed
Cap
and
Trade
(
C&
T)
rule.
Additional
analyses
of
Hg
deposition
patterns
for
2004
and
equivalent
patterns
under
the
MACT
and
C&
T
rules
have
now
been
carried
out.

These
additional
analyses
have
examined
the
deposition
that
would
result
from
utility
sources
that
are
projected
under
MACT
and/
or
C&
T
to
not
implement
controls
specifically
to
reduce
Hg
emissions.
Mercury
emissions
from
these
sources
(
in
addition
to
all
the
other
utility
sources
that
will
be
reducing
their
Hg
emissions)
are
found
to
have
insignificant
impacts
on
nearby
and
distant
deposition
patterns
for
the
C&
T
case,
relative
to
the
MACT
case.
Receiving
waters
downwind
from
these
locations
are
calculated
to
experience
no
significant
additional
deposition
due
solely
to
these
sources
individually
or
as
a
group
not
initiating
Hg­
specific
controls.
Thus,
under
EPA
and
other
definitions
of
utility
Hg
deposition
"
hot
spots,"
these
particular
sources
do
not
in
themselves
bring
about
"
hot
spot"
conditions
under
a
C&
T
rule
relative
to
either
a
MACT
rule
or
2004
emissions
conditions.

Measurements
of
speciated
Hg
in
the
ambient
atmosphere
are
needed
to
improve
our
understanding
of
the
atmospheric
fate
and
transport
of
Hg.
The
commenter
recommended
that
the
available
information
on
speciated
Hg
concentrations
be
used
to
(
1)
provide
insights
on
the
processes
that
appear
to
influence
Hg
speciation
in
the
atmosphere,
(
2)
evaluate
the
performance
of
global
and
continental
models
of
atmospheric
Hg
vs.
surface
and
aloft
data,
and
(
3)
quantify
the
limitations
and
possible
biases
of
those
models.
Those
limitations
and
biases
should
then
be
taken
into
account
when
evaluating
the
potential
benefits
of
Hg
emission
reductions.

The
MDN
data
are
extremely
useful
to
evaluate
the
ability
of
models
to
reproduce
the
regional
patterns
of
Hg
wet
deposition.
The
MDN
data
have
also
highlighted
the
fact
that
Hg
deposition
is
significantly
different
from
sulfate
deposition.
Sulfate
wet
deposition
shows
a
clear
west­
to­
east
increasing
gradient
whereas
Hg
wet
deposition
shows
primarily
a
north­
to­
south
increasing
gradient.
These
results
suggest
that
sulfate
wet
deposition
is
strongly
influenced
by
regional
emission
sources
whereas
Hg
is
not.
Instead,
Hg
wet
deposition
appears
to
be
influenced
primarily
by
oxidant
concentrations
that
are
conducive
to
the
oxidation
of
Hg0
to
Hg+
2.

Comment:
9­
183
One
commenter
(
OAR­
2002­
0056­
5497)
suggested
that
the
Mercury
Deposition
Network
(
MDN)
data
are
useful
in
evaluating
the
ability
of
models
to
reproduce
regional
patterns
of
wet
deposition
of
Hg.
However,
the
MDN
was
never
designed
to
monitor
the
local
deposition
of
Hg.
Consequently,
MDN
data
should
not
be
used
to
evaluate
model
predictions
of
near­
field
deposition.

For
the
reasons
detailed
in
EPRI's
NODA
comments
(
see
OAR­
2002­
0056­
5469),
the
commenter
agrees
that
the
Industrial
Source
Complex
(
ISC)
and
Regional
Lagrangian
Model
of
Air
Pollution
(
RELMAP)
models
used
for
the
Hg
Study
are
not
the
best
means
of
assessing
local
and
global
Hg
deposition.
These
models
are
outdated
and
do
not
reflect
the
current
state
of
the
science.
Whatever
model(
s)
EPA
ultimately
chooses,
EPA
must
recognize
that
a
grid­
based
model
may
over
predict
local
Hg
deposition
by
a
factor
of
two
or
more
when
compared
to
the
results
of
a
plume
model.

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
8
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
EPA's
air
quality
modeling
analysis.
Please
also
see
EPA's
Technical
Support
Document
for
the
Final
Clean
Air
Mercury
Rule:
Air
Quality
Modeling.

3.
Step
3:
Modeling
Ecosystem
Dynamics.
EPA
plans
to
quantify
Hg
deposition
associated
with
Hg
reductions
to
estimate
changes
in
human
exposure
to
methylmercury
that
may
result
from
reductions
in
power
plant
emissions.
This
requires
quantifying
the
linkage
between
different
levels
of
Hg
deposition
and
fish
tissue
methylmercury
concentration.
EPA
is
currently
considering
using
the
Water
Office's
Mercury
Maps
(
Mmaps)
for
this
purpose,
supplemented
by
case
studies,
and
requested
comment
on
this
approach.
To
complement
the
case
studies,
EPA
asked
for
both
empirical
information
and
modeled
scenarios
that
show
the
effects
of
ecosystem
properties
other
than
total
Hg
loading
on
accumulation
in
organisms
in
different
ecosystems
and,
specifically,
on
new
knowledge
related
to
factors
affecting
methylation
and
demethylation
in
a
range
of
aquatic
ecosystem
types.
EPA
also
sought
comment
on
data
and/
or
analytic
tools
that
can
be
used
to
forecast
methylation
rates
and
bioaccumulation
rates
in
aquatic
ecosystems.
EPA
received
analyses
of
the
changes
in
fish
concentrations
expected
as
a
result
of
changes
in
deposition
from
Chippewa
Indians
(
OAR­
2002­
0056­
2118),
Environmental
Defense
(
OAR­
2002­
0056­
2878),
Electric
Power
Research
Institute
(
OAR­
2002­
0056­
2578,
­
2589,
­
2593),
Hubbard
Brook
Research
Foundation
(
2038),
NESCAUM
(
OAR­
2002­
0056­
2887,
­
2890),
and
TXU
Energy
(
OAR­
2002­
0056­
1831)
and
asked
for
comment
on
their
analyses.

Comment:

One
commenter
(
OAR­
2002­
0056­
5544)
has
been
monitoring
Hg
in
sediments
and
fish
in
reservoirs
on
one
particular
river
and
its
tributaries
over
the
last
30
years.
Based
on
this
extensive
9­
184
data
set,
several
observations
can
be
made:

°
Mercury
levels
in
this
reservoir
sediment
have
declined
substantially
since
1973.
°
Mercury
content
in
fish
in
the
reservoirs
was
varied
but
has
generally
shown
constant
or
reducing
trends.
°
Generation
of
power
from
coal­
fired
facilities
in
the
region
has
increased
over
this
period.

The
commenter
has
been
working
in
cooperation
with
state
agencies
in
the
Tennessee
Valley
to
determine
the
overall
condition
of
streams
and
lakes
and
the
level
of
contaminants
in
fish
for
three
decades.
Mutual
efforts
specifically
related
to
Hg
began
in
1970
in
response
to
discovery
of
Hg
contaminated
fish
in
the
Great
Lakes
and
adoption
of
guidelines
for
Hg
in
fish
by
the
U.
S.
Food
and
Drug
Administration.
The
commenter
collected
a
variety
of
fish
species
and
sediment
samples
from
throughout
the
are
in
the
early
1970'
s
and
reported
current
fish
tissue
monitoring
program
began
in
1987
and
continued
as
part
of
their
Vital
Signs
Monitoring
Program.
The
commenter
has
monitored
hundreds
of
locations
throughout
the
Tennessee
Valley
over
the
years.

Mercury
levels
in
the
commenter's
area
reservoir
sediments
have
declined
substantially
since
1973.
The
commenter
conducted
a
special
study
in
1973
of
sediments
from
the
forebay
area
(
i.
e.,
the
area
just
upstream
of
a
dam)
of
26
reservoirs.
A
comparison
of
the
results
from
1973
with
recent
Vital
Signs
Monitoring
data
from
the
same
locations
indicates
a
substantial
decrease
in
Hg
concentrations
throughout
the
commenter's
area
from
the
early
1973s
to
the
late
1990s.
The
large
reduction
in
sediment
Hg
occurred
in
the
1970s
as
many
large
industrial
users
of
Hg
changed
production
methods
to
less
Hg­
intensive
operations.
In
locations
without
historical
industrial
point
sources
of
Hg,
no
increases
have
been
observed
in
sediment
Hg
concentration.

Mercury
levels
in
fish
tend
to
be
low
in
largemouth
bass
and
catfish
in
the
reservoirs
of
the
commenter's
main
river.
In
samples
collected
since
1990'
s
in
the
reservoirs,
largemouth
bass
show
a
mean
concentration
of
total
Hg
around
0.2
mg/
kg.
Largemouth
bass
are
routinely
included
in
many
studies
because
they
are
at
the
top
of
the
food
chain.
Since
1970,
the
Hg
concentrations
in
largemouth
bass
and
channel
catfish
have
remained
relatively
steady
with
no
apparent
increase.

In
furtherance
of
its
congressional
mandate
to
promote
the
safe
and
efficient
use
of
electric
energy,
the
commenter
has
long
supported
and
conducted
research
into
various
subjects
associated
with
the
generation
of
electricity.
This
includes
the
publication
of
various
technical
reports
and
studies.
Among
these
publications
are
a
series
of
"
On
the
Air"
reports
that
are
technical
notes
on
important
air
topics.
The
November
2004
"
On
the
Air"
focused
on
TVA's
sampling
of
Hg
levels
in
the
Tennessee
Valley
region
and
was
entitled,
"
Three
decades
of
Mercury
Levels
in
the
Tennessee
River
System".
The
commenter
is
enclosing
a
copy
of
this
document
with
our
comments.
It
presents
the
above
information
in
more
detail
and
shows
that
a
decline
in
Hg
concentrations
in
the
Tennessee
River
has
occurred
over
a
period
of
time
when
coal
combustion
has
increased
substantially
(
see
OAR­
2002­
0056­
5544).

Response:
9­
185
EPA
has
examined
the
commenter's
concerns
in
context
of
the
final
rulemaking.
As
described
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket,
we
have
limited
the
fish
tissue
samples
to
more
recent
years
for
some
analysis
in
part
for
reasons
similar
to
those
raised
by
the
commenter.

Comment:

One
commenter's
(
OAR­
2002­
0056­
5559)
studies
at
Little
Rock
Lake
in
northern
Wisconsin
indicated
that
environmental
improvement
may
be
occurring
from
actions
already
taken
to
reduce
Hg
air
emissions.
For
a
five­
year
period
beginning
in
1995,
researchers
measured
Hg
air
deposition,
and
levels
of
Hg
in
lake
water
and
in
fish
tissue.
The
studies
documented
declines
in
Hg
levels
for
all
these
parameters
with
reductions
of
Hg
levels
in
yellow
perch
tissue
averaging
5
percent
annually.
The
declines
measured
show
that
Little
Rock
Lake
is
responding
more
rapidly
to
changes
in
deposition
of
Hg
than
the
decline
in
acidity
from
sulfur
dioxide
emission
reductions.
This
is
a
promising
indication
that
reducing
Hg
deposition
will
lead
to
lower
lake
Hg
levels
as
well
as
a
reduction
in
fish
tissue.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
We
pursued
several
case
studies
as
described
in
Chapter
3
of
the
Regulatory
Impact
Analysis
that
address
time­
lags
at
various
ecosystems.

Comment:

One
commenter
(
OAR­
2002­
0056­
5517)
notes
that
as
demonstrated
by
peer­
reviewed
research
performed
by
scientists
at
Princeton
University,
the
level
of
methymercury
in
the
world's
oceans
is
not
controlled
by
atmospheric
Hg.
In
this
respect,
a
particularly
significant
omission
of
the
NODA
is
its
failure
to
note
the
observation
of
these
Princeton
University
scientists
whose
findings
provide
strong
evidence
that
the
concentration
of
MeHg
in
the
world's
oceans
does
not
respond
to
anthropogenic
emissions
of
Hg.
Rather,
oceanic
biogeochemical
processes,
possibly
involving
deep
ocean
sediments,
control
the
level
of
methymercury
in
the
world's
oceans.
Thus,
this
commenter
believes
that
regardless
of
what
Hg
emissions
controls
are
put
in
place
at
coal­
fired
power
plants,
the
levels
of
MeHg
in
ocean
fish
will
remain
virtually
unchanged.

The
commenter
points
out
that
EPA,
in
its
NODA,
has
produced
no
peer­
reviewed
data
that
would
contradict
the
finding
of
the
Princeton
study.
Moreover,
the
Princeton
study
aside,
given
the
fact
that
the
world's
oceans
contain
millions
of
tons
of
Hg,
reducing
some
or
even
all
of
the
less
than
50
tons
of
Hg
emissions
released
from
U.
S.
coal­
fired
power
plants
will
leave
the
levels
of
Hg
in
the
world's
oceans
virtually
unchanged.
Consequently,
the
levels
of
MeHg
in
the
ocean
fish
that
Americans
eat
every
day
will
be
virtually
unchanged.
Unless
EPA
can
produce
peer­
reviewed
data
that
convincingly
contradicts
the
Princeton
study
findings,
it
must
be
presumed
as
prima
facie
evidence
arguing
against
any
assertion
by
EPA
that
curtailing
Hg
emissions
from
power
plants
would
have
any
effect
on
the
level
of
MeHg
found
in
ocean
fish.
9­
186
If
the
Princeton
study
is
correct
concerning
the
constancy
of
the
amount
of
Hg
in
the
world's
oceans,
then
the
modeling
EPA
proposes
to
use
to
estimate
reductions
of
MeHg
in
marine
fish
is
entirely
inappropriate
and
must
not
be
used.
This
is
because
the
models,
by
their
very
design,
would
incorrectly
predict
that
lowering
emissions
of
Hg
from
coal­
fired
power
plants
will
in
fact
lower
the
levels
of
MeHg
in
the
ocean.

However,
actual
oceanic
field
data
taken
by
the
Princeton
University
scientists
clearly
indicate
that
this
is
not
the
case
and
that
regardless
of
whether
atmospheric
levels
of
Hg
change,
the
level
of
MeHg
in
the
ocean
remains
unchanged.
No
model
that
EPA
proposes
to
use
reflects
this
fact.
If
these
scientists
are
correct
in
their
surmisal,
then
limiting
emissions
of
Hg
from
coal­
fired
power
plants
will
have
absolutely
no
significant
effect
on
the
levels
of
MeHg
in
marine
fish,
consumption
of
which
constitutes
the
major
route
of
human
exposure
to
this
chemical.
The
commenter
states
that
this
important
finding
has
a
very
significant
bearing
on
estimates
of
the
benefits
of
reducing
power
plant
emissions
of
Hg
and
must
be
taken
into
account.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
For
several
reasons
described
in
the
Regulatory
Impact
Analysis,
EPA
focused
its
analysis
on
recreationally
caught
freshwater
fish.

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
did
not
agree
with
the
EPA
formal
definition
of
a
Hg
hot
spot.
The
definition
based
on
modeling
Hg
deposition
rates
by
utilities
and
determining
how
the
removal
of
those
emissions
will
hypothetically
reduce
the
amount
of
MeHg
in
fish
is
flawed
logic.
A
Hg
hot
spot
is
an
existing
area
or
region
which
already
has
had
its
natural
resources
(
fish
and
wildlife)
adversely
impacted
by
Hg
emissions
resulting
in
the
issuance
of
fish
advisories
to
protect
public
health.
Existing
Hg
concentrations
in
fish
and
wildlife
should
be
used
to
define
Hg
hot
spots.

The
proposed
scale
of
modeling
responses
of
fish
tissues
to
changes
in
Hg
emissions
to
the
atmosphere
is
unclear
in
the
NODA.
National­
scale
modeling
would
appear
to
have
a
tendency
to
dilute
or
obscure
the
benefits
of
reduced
Hg
emissions,
particularly
for
the
northeastern
and
east
coast
states.
This
dilution
or
obscuring
of
benefits
is
not
scientifically
sound
or
acceptable.
For
fresh
waters
of
the
U.
S.,
modeling
should
be
scaled
to
at
least
a
regional
basis
although
benefits
of
Hg
emission
reductions
will
be
even
greater
in
localities
and
waters
with
closer
proximity
to
the
sources
of
Hg
emissions.

Response:

EPA
has
addressed
the
hot
spots
issue
in
the
revision
Federal
Register
notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.
9­
187
Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
stated
that
power
plant
emission
reductions
will
reduce
Hg
deposition
in
the
Eastern
U.
S.,
and
MeHg
concentrations
in
wild
freshwater
fish
are
likely
to
drop
in
response.
Much
of
the
freshwater
fish
consumed
in
the
U.
S.
is
farm­
raised,
and
does
not
contribute
significantly
to
exposure.
But
because
so
much
more
marine
fish
than
wild
freshwater
fish
is
consumed,
the
affect
on
total
exposure
is
modest.
The
range
of
exposure
reduction
from
Hg
controls
under
any
of
the
scenarios
under
consideration
was
from
0.4­
6.5
percent,
depending
on
the
state.
The
average
of
the
calculated
state
reduction
was
about
1.6
percent.
These
reductions
apply
to
those
who
eat
a
typical
mix
of
marine
and
wild
freshwater
fish,
based
on
state
recreational
fishing
data.
Some
members
of
the
population
such
as
subsistence
fishers
may
experience
greater
exposure
reductions.

EPA's
MMaps
tool
assumes
that
1)
there
is
a
linear
relationship
between
atmospheric
deposition
and
MeHg
in
fish,
2)
atmospheric
deposition
is
the
only
significant
source
of
Hg
to
lakes,
and
3)
fish
tissue
Hg
is
at
steady
state
equilibrium
with
the
water.
Data
(
from
the
METAALICUS
study)
and
modeling
results
negating
these
assumptions
are
provided.
Furthermore,
it
is
still
not
possible
to
accurately
forecast
either
the
lag
time
or
the
level
of
response
of
fish
tissue
following
reductions
in
Hg
deposition.
Modeling
runs
with
the
commenter's
Dynamic
Mercury
Cycling
Model
have
indicated
lag
times
of
decades
to
more
than
100
years.
Regardless
of
the
complexity
of
models
describing
the
behavior
of
Hg
in
the
environment,
characteristics
of
both
terrestrial
and
aquatic
ecosystems
such
as
microbial
activity,
pH,
dissolved
organic
matter,
algal
productivity,
redox
potential,
temperature,
hydrodynamics,
etc.
make
it
very
difficult
to
accurately
conduct
broad­
brush
regional
modeling
of
the
responses
of
fish
tissues
to
reductions
in
atmospheric
Hg
deposition.

Reductions
in
Hg
emissions
from
U.
S.
coal­
fired
power
plants
will
have
only
a
small
effect
on
U.
S.
exposures
to
MeHg.
This
is
because
most
exposure
to
MeHg
occurs
through
consumption
of
marine
fish.
Marine
fish
will
be
largely
unaffected
by
U.
S.
power
plant
emission
reductions
because
the
reductions
are
so
small,
less
than
1
percent,
of
global
emissions.
The
predominance
in
U.
S.
commerce
of
North
Pacific
marine
fish
implies
an
even
lower
sensitivity
to
U.
S.
Hg
reductions,
due
to
prevailing
winds
and
the
uncertainty
about
the
availability
of
MeHg
in
marine
environments.

Response:

The
benefits
analysis
completed
for
the
RIA
is
not
intended
to
model
local­
scale
changes
in
fish
tissue
concentrations
and
exposures
in
support
of
site­
specific
risk
analysis.
Instead,
modeling
conducted
for
the
RIA
is
intended
to
capture
generalized
regional
changes
in
methlmercury
exposure
resulting
from
reductions
in
power
plant
mercury
emissions
in
order
to
support
a
national­
scale
benefits
assessment
focusing
on
the
37­
State
eastern
U.
S.
study
area.
For
additional
details
on
the
benefits
analysis
modeling
framework
see
Section
10
of
the
RIA.

EPA
recognizes
the
complexities
associated
with
methylation
of
mercury
deposited
in
waterbodies
and
watersheds
and
subsequent
biomagnification
within
the
aquatic
foodweb.
While
9­
188
there
are
dynamic
fate/
transport
models
that
can
be
used
to
conduct
detailed
site­
specific
modeling
of
mercury
in
aquatic
and
terrestrial
environments
for
purposes
of
predicting
mercury
fish
tissue
concentrations
(
e.
g.,
the
dynamic
mercury
cycling
model),
it
is
not
feasible
to
utilize
these
resource­
intensive
models
for
a
regional­
or
nationals­
scale
analysis.
Therefore,
EPA
selected
the
MMAPs
models
for
application
in
the
RIA.
EPA
fully
recognizes
the
limitations
and
simplifying
assumptions
associated
with
this
model,
but
believes
that
it
has
sufficient
precision
to
support
a
benefits
analysis
conducted
at
the
regional­
or
national­
scale
(
i.
e.,
it
can
capture
general
trends
in
mercury
fish
tissue
response
to
changes
in
mercury
deposition
from
power
plants).
However,
to
provide
additional
perspective
on
the
relationship
between
mercury
deposition
and
fish
tissue
concentration
changes
(
especially
in
relation
to
MMAPS
linearity
assumption
and
the
lag
time
required
for
systems
to
reach
steady
state),
EPA
has
conducted
several
detailed
local­
scale
sensitivity
analyses.
The
results
of
these
case
studies
are
presented
and
discussed
in
Appendix
D.

EPA
recognizes
both
(
a)
the
technical
challenges
in
predicting
the
change
in
saltwater
fish
mercury
concentrations
resulting
from
reductions
in
US
power
plant
emissions
and
(
b)
the
relatively
small
contribution
that
US
power
plants
make
to
total
deposition
over
saltwater
habitats
for
commercial
fish
(
Note,
however
that
because
of
the
high
proportion
of
US
fish
consumption
associated
with
saltwater
fish,
even
a
relatively
low
impact
of
US
power
plant
emissions
on
those
fish
could
produce
significant
benefits).
Because
primarily
of
technical
challenges
in
translating
mercury
emissions
reductions
from
US
power
plants
into
changes
in
saltwater
fish
mercury
concentrations,
EPA
has
not
included
this
exposure
pathway
(
saltwater
fish
consumption)
in
the
primary
benefits
analysis.

EPA
agrees
with
the
commentor
that
there
is
significant
uncertainty
associated
with
predicting
the
lag
(
time)
required
for
fish
to
reach
new
steady
state
mercury
concentrations
following
reductions
in
mercury
deposition
to
watersheds/
waterbodies.
EPA
also
recognizes,
that,
depending
on
the
specific
aquatic
system
under
consideration,
lag
times
could
extend
over
decades.
Consequently,
EPA
has
provided
benefits
results
in
the
RIA
reflecting
a
range
of
lag
periods
(
from
0
years
to
100
years).

Comment:

One
commenter
(
OAR­
2002­
0056­
5465)
stated
that
even
working
within
the
narrowly
framed
revised
benefits
assessment
proposed
by
EPA,
numerous
issues
arose.
The
commenter
hereby
incorporated
by
reference
the
arguments
elaborated
in
the
attached
articles
insofar
as
they
spoke
to
the
questions
raised
by
the
NODA.
In
particular,
the
commenter
drew
EPA's
attention
to
the
discussion
and
sources
cited
by
Professor
O'Neill
regarding
the
biological,
chemical,
and
physical
processes
relevant
to
determining
Hg
exposure
for
those
in
the
upper
Great
Lakes.

Response:
EPA
appreciates
the
commenters
concerns.
EPA
addresses
ecosystem
response
to
mercury
loading
in
Chapter
3
of
the
Regulatory
Impact
Analysis.

Comment:
9­
189
One
commenter
(
OAR­
2002­
0056­
5535)
presented
several
specific
issues
that
would
benefit
from
such
careful
peer
review.
The
commenter
did
not
intend
this
list
to
be
comprehensive,
but
merely
include
it
to
illustrate
that
the
agency
must
address
critical
scientific
issues
prior
to
making
changes
to
its
deposition
and
watershed
models
or
conducting
other
components
of
the
proposed
analyses.
This
overview
serves
to
demonstrate
that
it
would
be
foolish
to
hold
up
final
Hg
regulations
while
EPA
further
investigates
certain
technical
issues
concerning
the
emissions,
fate,
and
toxicity
of
Hg
from
power
plants.

Hg
Speciation
in
Deposition
Modeling.
The
NODA
points
out
that
HBRF
said
that
an
average
speciation
profile
should
not
be
used
when
modeling
or
estimating
deposition.
This
statement
was
made
in
the
context
of
Hg
deposition
modeling
because
using
an
average
speciation
profile
for
emissions
would
likely
underestimate
the
amount
of
local,
regional
and
continental
deposition.
This
is
because
speciation
drives
assumptions
about
the
residence
time
of
Hg
in
the
atmosphere,
which
controls
transport
and
the
likelihood
that
Hg
emitted
in
the
U.
S.
will
deposit
in
outside
the
U.
S.
For
example,
the
more
Hg
emitted
as
elemental,
the
higher
the
proportion
of
Hg
that
is
transported
longer
distances.
In
particular,
the
EPA
should
incorporate
new
speciation
data
for
Northeast
plants.
A
revised
speciation
profile
for
Northeast
plants
is:
70
percent
oxidized
Hg
and
30
percent
elemental
Hg.

Hg
Maps
(
MMAPS).
MMAPS
is
a
useful
tool
for
roughly
evaluating
the
impacts
of
Hg
deposition
on
fish
Hg
levels.
However,
as
the
agency
notes,
it
is
still
undergoing
external
peer
review
and
the
commenter
expects
the
agency
will
need
time
to
address
peer
review
comments.
Hindering
the
applicability
of
MMAPs
is
the
lack
of
fish
concentration
data
for
many
watersheds
and
the
"
averaging"
of
results
across
large
watersheds.
The
commenter
thought
MMAPS
was
best
suited
to
the
application
for
which
it
was
developed
 
evaluating
specific
watersheds
where
additional
information
on
population
exposure
can
be
considered
when
evaluating
the
results
of
the
assessment.

Response:

EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.
See
the
Regulatory
Impact
Analysis
and
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket
for
a
discussion
of
the
application
of
Mercury
Maps
assumption.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
presented
a
figure
illustrating
no
evidence
of
9­
190
increasing
trend
or
any
change
in
Hg
of
deep­
sea
fish
(
blue
hake):
1970s
versus
1880s
fish
(
Figure
E1,
see
OAR­
2002­
0056­
5423).

"
To
test
for
a
change
in
mercury
content
in
the
last
century,
two
samples
of
the
deep­
sea
fish
named
blue
hake
(
Antimora
rostrata)
were
analyzed.
Antimora
rostrata
is
resident
throughout
the
world's
oceans
at
depths
of
1000­
3000
m
but
does
not
venture
into
depths
shallower
than
800
m
[
actually
about
200
m
in
the
cold
waters
of
the
polar
region];
therefore,
this
deep­
sea
species
is
not
exposed
to
local
estuarine,
coastal,
or
atmospheric
inputs
of
mercury.
A
sample
of
21
specimens
collected
in
the
1880s
was
compared
with
a
sample
of
66
specimens
collected
in
the
1970s
in
the
western
North
Atlantic
Ocean.
In
both
recent
and
old
fish
mercury
increased
as
a
function
of
length,
but
comparison
of
the
two
concentration
vs.
length
relationships
shows
that
there
has
not
been
an
increase
in
mercury
concentration
in
deep­
sea
fish
in
the
last
century.
This
result
supports
the
idea
that
the
relatively
high
concentration
of
mercury
found
in
marine
fish
that
inhabit
the
surface
and
deep
waters
of
the
open
ocean
result
from
natural
processes,
not
20th
century
industrial
pollution."
[
Barber
et
al.
(
1984)
Environmental
Science
&
Technology,
vol.
18,
552­
555;
Barber
et
al.
(
1972)
Science,
vol.
178,
636­
639]

This
commenter
presented
a
figure
(
Figure
E1,
see
OAR­
2002­
0056­
5423)
showing
that
although
one
can
find
a
clear
increase
of
Hg
concentration
in
the
tissue
of
the
deep
sea
fish
(
blue
hake)
caught
from
western
Atlantic
waters
as
the
size
of
the
fish
increases,
one
can
hardly
see
any
significant
changes
in
the
fish
tissue
Hg­
size
relation
for
fish
samples
caught
in
1880s
when
compared
to
the
modern
samples
caught
in
the
1970s.
This
research
clearly
suggests
that
Hg
concentration
in
world
ocean
fish
is
not
likely
to
be
changed
or
modified
by
any
amount
of
alteration
of
inorganic
Hg
sources
(
either
anthropogenic
or
natural).
This
is
why
the
claim
that
the
current
EPA
CAMR
will
lead
to
a
measurable
reduction
in
MeHg
accumulated
in
world
ocean
fish
or
even
fish
from
local
U.
S.
lakes
is
factually
misleading.
Additional
evidence
and
comments
by
the
commenter
follow.

Figure
E2
,
(
see
OAR­
2002­
0056­
5423)
shows
recent
results
by
Kraepiel
et.
al.,
(
2003,
Environmental
Science
&
Technology,
vol.
37,
5551­
5558)
which
found
no
clear
increase
in
the
Hg
levels
of
Yellowfin
tuna
caught
in
1998
relative
to
a
similar
cohort
caught
in
1971.

The
theoretical
expectation
(
similar
to
EPA's)
was
that
the
MeHg
concentration
"
should
have
increased
by
9
to
26
percent"
over
the
interval
"
if
methylation
occurred
in
the
mixed
layer
or
in
the
thermocline
[
of
the
Pacific
oceans]."
The
theory
was
not
proven.
The
commenter
further
noted
that
Zhang
et
al.
(
2002,
Ambio,
vol.
31,482­
484)
has
recently
estimated
that
China's
Hg
emissions
from
coal
combustion
are
increasing
at
the
rate
of
5
percent
per
year
(
from
available
data
from
1978
through
1995),
which
is
consistent
with
the
theoretical
expectation
of
increase
in
the
amount
of
MeHg
in
the
waters
of
the
Pacific
Ocean
if
the
Hg­
to­
MeHg
conversion
process
is
sensitive
to
industrial
emissions.
To
the
contrary,
Kraepiel
et
al.
(
2003)
clearly
concluded
that
"[
s]
uch
an
increase
is
statistically
inconsistent
with
the
constant
Hg
concentrations
measured
in
9­
191
tuna.
The
commenter
concluded
tentatively
that
Hg
methylation
in
the
oceans
occurs
in
deep
waters
or
in
sediments."
(
p.
5551).
This
is
why
the
relatively
small
man­
made
sources
of
Hg
emissions
can
neither
overwhelm
nor
directly
alter
the
natural
cycling
of
Hg
in
the
environment
and
biosphere.

Independent
results
shown
in
Figure
E3
(
see
OAR­
2002­
0056­
5423)
support
and
update
the
finding
of
Zhang
et
al.
(
2002)
that
industrial
Hg
emissions
from
China
(
and
India)
are
increasing
significantly
from
1990
to
2000
and
that
amount,
both
in
the
absolute
amount
and
the
rate
of
increase,
dwarfed
the
rather
small
amount
of
industrial
Hg
emissions
from
the
U.
S.
EPA's
CAMR
should
seriously
consider
and
weighing
this
important
fact
if
there
is
to
be
any
effective
Hg
emission
management
rulings.

Figure
E4
(
see
OAR­
2002­
0056­
5423)
shows
additional
new
evidence
against
any
increasing
trend
in
Hg
levels
in
fish
by
examining
concentrations
in
tissue
of
striped
bass
from
the
San
Francisco
Bay
area
over
the
period
1970­
2000.
The
study's
findings
also
clearly
show
that
in
any
given
year
there
is
at
least
one
striped
bass
sample
containing
Hg
values
above
EPA's
consumption
advisory
threshold
value
of
0.5
ppm.
Perhaps
even
more
significant,
those
striped
bass
with
Hg
concentration
values
above
0.5
ppm
had
no
apparent
connection
to
power
plant
Hg
emissions.

Figure
E4
(
see
OAR­
2002­
0056­
5423)
illustrates
no
evidence
of
increasing
trend
in
Hg
concentration
in
striped
bass
caught
off
San
Francisco
Bay
area
from
1970­
2000.
The
commenter
notes
that
at
any
given
year
there
is
at
least
one
striped
bass
with
Hg
level
above
the
EPA's
consumption
advisory
threshold
of
0.5
ppm
since
1970
with
no
apparent
tie
to
any
U.
S.
power
plant
Hg
emission
sources.
Also
although
no
increasing
trend
is
clear
for
Hg,
declines
were
noted
in
the
fish
tissue's
DDT
and
chlordane
in
the
late
90s.
Those
declines
may
be
related
to
the
use
curtailment
of
these
two
chemicals
in
the
70s
and
80s.

Figure
E4
(
see
OAR­
2002­
0056­
5423)
reveals
another
important
finding
from
this
new
study.
Even
though
no
accumulation
trend
was
noted
for
Hg
in
striped
bass
in
the
1970­
2000
period,
significant
declines
in
the
late
1990s
were
noted
for
other
contaminants
like
DDT
and
chlordane
in
San
Francisco
Bay's
fish
tissues.
The
authors
suggest
that
the
declines
may
be
linked
to
known
curtailed
usage
of
the
two
chemicals
in
the
1970s
and
1980s.
Thus,
the
combined
findings
suggest
a
more
complicated
and
complex
chain
of
biomethylation
and
bioaccumulation
for
Hg
in
fish.
That
is,
compared
to
other
contaminants
it
appears
that
the
pathway
and
behavior
of
Hg
transformation
and
accumulation
in
fish
differs
significantly.

A
similar
tendency
was
recently
reported
(
Yamaguchi
et
al.,
2003,
Chemosphere,
vol.
50,
265­
273)
for
levels
of
contaminants
in
fish
from
upper
River
Thames
in
Britain
by
a
group
of
zoologists
from
Oxford
University
and
Cornell
University.
These
authors
concluded
that
although
the
recent
decrease
in
environmental
contamination
level
of
PCBs
may
be
partly
associated
with
industrial
and
human
activities,
it
was
difficult
to
find
such
associations
for
Hg.

Response:
9­
192
EPA
appreciates
the
commenter's
input
to
the
record.
For
several
reasons
described
in
the
Regulatory
Impact
Analysis,
EPA
focused
its
analysis
on
recreationally
caught
freshwater
fish.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
presented
a
figure
(
Figure
F1,
see
OAR­
2002­
0056­
5423)
that
confirms
admission
by
EPA
that
trace
levels
of
MeHg
in
fish
depend
on
the
complex
physical,
chemical,
and
biological
factors
within
each
unique
ecosystem.
More
importantly,
it
evidences
that
despite
the
relatively
constant
level
of
total
inorganic
Hg
available
in
all
four
(
3
open
water
and
1
salt
marshland)
of
the
sampling
sites
(
the
four
blue
bars
in
Figure
F1)
in
this
study,
the
production
and
concentration
levels
of
MeHg
were
significantly
enhanced
at
the
biologically
active
and
organically
rich
marsh
wetland
site
(
the
tallest
red
bar
marked
"
marsh"
in
Figure
F1).
The
authors
concluded
that
"
sediment
geochemistry
(
redox,
sulfide,
pH,
organic
content,
etc.)
is
a
much
more
important
control
on
MeHg
production
than
is
the
absolute
total
mercury
concentration"
(
p.
266
of
Marvin­
DiPasquale
et.
al.,
2003,
Environmental
Geology,
vol.
43,
260­
267).

The
San
Francisco
Bay
findings
add
to
the
body
of
evidence
showing
that
either
adding
or
reducing
Hg
atmospheric
deposition
from
any
coal­
fired
power
plant
would
not
measurably
affect
MeHg
levels
in
the
San
Francisco
Bay
ecosystems.
To
the
contrary,
MeHg
levels
are
naturally
self­
limited
by
specific
ecosystem
dynamics,
water
quality
variables
like
dissolved
sulfate,
parameters
like
the
population
of
algae
and/
or
zooplankton,
availability
of
nutrients
and/
or
sunlight
and
so
on.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
For
several
reasons
described
in
the
Regulatory
Impact
Analysis,
EPA
focused
its
analysis
on
recreationally
caught
freshwater
fish.

Comment:

Generally
agreeing
with
EPA's
assessment,
one
commenter
(
OAR­
2002­
0056­
5423)
offers
an
additional
new
and
important
model
validation
target
for
EPA's
modeling
team
to
factor.
Figure
G1
(
see
OAR­
2002­
0056­
5423)
shows
a
very
important
observation
concerning
the
accumulation
of
MeHg
in
various
watershed
systems.
It
shows
a
particular
"
MeHg
accumulation
paradox"
in
that
the
relative
percentage
of
MeHg
converted
from
raw
Hg
available
actually
decreases
as
the
amount
of
raw
Hg
available
increases.
The
authors
of
these
important
findings
suggest
that
as
the
amount
of
raw
Hg
increases
in
a
watershed
system,
there
are
actually
more
bacterial
operons
(
i.
e.,
bacterial
enzymes
encoded
by
the
Hg
resistance
(
mer)
operon)
available
to
significantly
break
down
the
MeHg
produced,
and
thus
explaining
the
observed
"
MeHg
accumulation
paradox."
Again,
the
proposed
EPA's
CAMR
needs
to
fully
account
for
the
underlying
science
before
making
costly
and
ineffectual
compliance
rulings.
9­
193
Response:

EPA
appreciates
the
commenter's
input
to
the
record.
EPA's
ecosystem
modeling
is
described
in
detail
in
Chapter
3
of
the
Regulatory
Impact
Anaysis.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
believed
it
is
very
important
to
emphasize
that
the
best
available
science
suggests
repeatedly
that
the
stated
assumptions
in
EPA's
MMaps
model
are
likely
to
be
wrong.
Therefore,
they
cannot
be
meaningfully
applied
for
a
realistic
assessment
of
how
a
change
in
Hg
emissions
from
power
plants
can
possibly
affect
concentrations
of
MeHg
in
fish.

First,
Figure
D1
(
see
OAR­
2002­
0056­
5423)
provides
real
data
that
"
the
physical,
chemical,
and
biological
characteristics
of
the
ecosystem(
s)"
never
remained
constant
over
time.
That
alone
invalidates
the
critical
model
assumption.

Figure
H1
(
see
OAR­
2002­
0056­
5423)
offers
another
important
target
for
validating
the
assumptions
in
EPA's
MMaps
model.
It
shows
that
local
atmospheric
deposition
of
Hg
has
negligible
contribution
to
the
annual
budget
of
Hg
to
the
Lake
Whatcom
ecosystems,
thus
directly
challenging
EPA's
MMaps
assumption
that
"
air
deposition
is
the
only
significant
source
of
Hg
to
a
water
body."

No
local
man­
made
Hg
"
pollution"
at
Lake
Whatcom,
Bellingham,
WA:
Annual
input
of
Hg
from
local
industrial
sources
is
negligible
Paulson
(
2004)
Sources
of
mercury
in
sediments,
water,
and
fish
of
the
Lakes
of
Whatcom
County,
Washington,
U.
S.
Geological
Survey
Scientific
Investigations
Report
2004­
5084
(
August
2004)

The
author
of
the
new
Lake
Whatcom
study
further
noted:

"
Concerns
about
mercury
(
Hg)
contamination
in
Lake
Whatcom,
Washington,
were
raised
in
the
late
1990s
after
a
watershed
protection
survey
reported
elevated
concentrations
of
Hg
in
smallmouth
bass.
The
USGS
...
cooperated
to
develop
a
study
to
review
existing
data
and
to
collect
new
data
that
would
lead
to
a
better
understanding
of
Hg
deposition
to
Lake
Whatcom
and
other
lakes
in
Whatcom
County.
Of
all
the
lakes
examined,
basin
1
of
Lake
Whatcom
would
have
been
most
affected
by
the
Hg
emissions
from
the
chlor­
alkali
plant
and
the
municipal
sewage­
sludge
incinerator
in
the
City
of
Bellingham.
The
length­
adjusted
concentrations
of
Hg
in
largemouth
and
smallmouth
bass
were
not
related
to
estimated
deposition
rates
of
Hg
to
the
lakes
from
local
atmospheric
sources.
Hg
concentrations
in
dated
sediment
core
samples
indicate
that
increase
in
Hg
sedimentation
were
largest
during
the
first
half
of
the
20th
century.
Increases
in
9­
194
Hg
sedimentation
were
smaller
after
the
chlor­
alkali
plant
and
the
incinerators
began
operating
between
1964
and
1984.
Analysis
of
sediments
recently
deposited
in
basin
1
of
Lake
Whatcom,
Lake
Terrell,
and
Lake
Samish
indicates
a
decrease
in
Hg
sedimentation."
(
p.
1
of
Paulson,
Sources
of
mercury
in
sediments,
water,
and
fish
of
the
Lakes
of
Whatcom
County,
Washington,
U.
S.
Geological
Survey
Scientific
Investigations
Report
2004­
5084,
August
2004)

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
EPA's
ecosystem
modeling
is
descbribed
in
detail
in
Chapter
3
of
the
Regulatory
Impact
Analysis.
Also
see
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
believed
that
it
should
be
fairly
clear
from
the
peer­
reviewed
literature
exhibited
in
comments
(
A)
through
(
H)
that
EPA's
MMaps
isn't
simply
suffering
from
"
limitations,"
but
is
instead
terminally
overwhelmed
by
numerous
demonstrably
flawed
assumptions
in
its
irrational
determination
to
claim
a
reduction
of
Hg
emissions
from
U.
S.
power
plants
can
or
will
lead
to
a
reduction
in
accumulation
of
MeHg
in
ocean
or
U.
S.
freshwater
fish.

Figure
I1
(
see
OAR­
2002­
0056­
5423)
presents
for
EPA's
modelers
yet
additional,
recently
published
fish
Hg
data
sets
of
various
sport
fish
species
caught
from
17
"
areas
of
concern
for
Hg
contamination"
in
the
Canadian
Great
Lakes
from
1971
to
1997.
The
results
again
evidence
that
historical
changes
in
Hg
concentrations
are
not
simply
to
be
expected
from
local
industrial
Hg
emissions.
In
fact,
the
author
concluded
that,
"
Differences
observed
[
among
different
areas
of
concern]
did
not
consistently
parallel
expectations
associated
with
historical
presence
of
chlor­
alkali
plants
in
the
vicinities
of
some
locations."
More
importantly,
the
author
also
noted
that
"
An
attempt
to
correlate
the
fish
tissue
Hg
with
the
frequency
of
occurrence
of
infantile
cerebral
palsy
at
AOC
[
areas
of
concern]
was
unsuccessful."
Further
Hg­
related
health
issues
are
addressed
in
comments
(
K)
through
(
Q)
in
e­
docket
text.

"
The
tissue
mercury
concentration
in
six
species
of
fish
collected
at
the
17
Areas
of
Concern
[
AOC]
were
analyzed.
A
linear
increase
in
Hg
concentration
with
fish
length
was
found,
but
slopes
differed
among
locations.
The
temporal
pattern
over
the
period
1971­
1997
differed
across
species
in
fish
collected
in
Lake
St.
Clair;
in
at
least
two
species
there
was
evidence
of
increased
Hg
concentration
during
the
1990s
that
had
been
suggested
in
an
earlier
analysis.
AOC
differed
significantly
in
observed
tissue
concentrations.
Differences
observed
did
not
consistently
parallel
expectations
associated
with
historical
presence
of
chlor­
alkali
plants
in
the
vicinities
of
some
locations.
An
attempt
to
correlate
the
fish
tissue
Hg
with
the
frequency
of
occurrence
of
infantile
cerebral
palsy
at
AOC
was
unsuccessful."
9­
195
Response:

EPA
appreciates
the
commenter's
input
to
the
record.
The
limitations
and
aplication
of
Mercury
Maps
is
described
in
detail
in
the
RIA
and
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
notes
that
this
partial
admission
on
the
highly
limited
use
of
MMaps
by
EPA
goes
a
long
way
toward
illustrating
the
commenter's
concerns
regarding
the
scientifically
questionable
direction
of
EPA's
modeling
effort.
Figure
J1
(
see
OAR­
2002­
0056­
5423)
confirms
that
the
top
15
fish
and
sea
foods
consumed
in
the
U.
S.,
representing
about
90
percent
of
the
U.
S.
commercial
market,
is
accounted
for
by
marine
and
farm­
raised
species.
(
According
to
UN
statistics,
domestic
fresh
water
fish
may
account
for
as
little
as
0.05
percent
of
total
U.
S.
consumption.)
This
alone
renders
EPA's
MMaps
modeling
results
on
MeHg
levels
in
freshwater
fish
almost
irrelevant
or
largely
insignificant.

Considering
the
insignificant
Hg
emissions
from
U.
S.
coal­
fired
power
plants
(
i.
e.,
less
than
1
percent
of
annual
global
emissions
budget)
and
the
millions
of
tons
of
natural
Hg
available
in
world
oceans
from
deep
venting,
it
is
clear
that
there
will
be
no
detectable
change
in
trace
MeHg
in
oceanic
fish
even
if
EPA
were
to
impose
zero
emission
standards
for
all
U.
S.
Hg
sources.
Evidence
provided
in
comment
(
E)
(
i.
e.,
Figures
El,
E2
and
E4,
see
OAR­
2002­
0056­
5423)
alone
should
be
adequate
for
our
hypothesis.
(
If
trace
levels
of
MeHg
did
not
increase
in
a
wide
variety
of
fish
along
with
rapidly
growing
worldwide
anthropogenic
emissions
(
See
figure
E3),
what
rationale
is
there
that
fish
MeHg
levels
would
drop
in
response
to
falling
U.
S.
emissions?)
Meanwhile,
the
strictest
burden
of
proof
for
EPA
rule
making
demands
a
clear
demonstration
(
not
invalid
modeling
assumptions)
that
its
CAMR
rulings
can
deliver
a
clear
and
meaningful
reduction
in
MeHg
in
world
ocean
fish.
Seafood
Consumed
in
the
U.
S.
Accounts
for
90
percent
of
the
Commercial
Market.
Source:
Carrington
and
Bolger
(
2002)
Risk
Analysis,
vol.
22,689­
699
+
updates
in
Carrington
and
Bolger
(
2003)
`
s
Intervention
Analysis
Draft
Report.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
The
limitations
and
aplication
of
Mercury
Maps
is
described
in
detail
in
the
RIA
and
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

Using
a
global
model
such
as
the
GEOS­
CHEM
model
to
provide
the
boundary
conditions
for
a
continental
model
(
REM
SAD
or
CMAQ)
is
a
more
scientifically
sound
approach
than
prescribing
those
regional
boundary
conditions.
It
is
necessary
to
conduct
a
performance
9­
196
evaluation
of
the
global
model
to
ensure
that
the
boundary
conditions
provided
to
the
continental
model
are
realistic.
It
is
also
desirable
to
have
a
consistent
formulation
of
the
physical
and
chemical
processes
governing
the
Hg
species
concentrations
in
both
the
global
and
continental
models.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
For
discussion
of
the
air
quality
modeling,
please
see
chapter
8
of
the
RIA
and
EPA's
Technical
Support
Document
for
the
Final
Clean
Air
Mercury
Rule:
Air
Quality
Modeling.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
presented
several
specific
issues
that
would
benefit
from
such
careful
peer
review.
They
did
not
intend
this
list
to
be
comprehensive,
but
merely
included
it
to
illustrate
that
the
agency
must
address
critical
scientific
issues
prior
to
making
changes
to
its
deposition
and
watershed
models
or
conducting
other
components
of
the
proposed
analyses.
This
overview
serves
to
demonstrate
that
it
would
be
foolish
to
hold
up
final
Hg
regulations
while
EPA
further
investigates
certain
technical
issues
concerning
the
emissions,
fate,
and
toxicity
of
Hg
from
power
plants.

Atmospheric
Hg
reactions.
Another
problem
with
EPRI's
global
Hg
model
is
the
incorporation
of
atmospheric
Hg
reactions
that
are
very
uncertain.
In
particular,
the
incorporation
and
effect
of
Hg
reduction
reactions
needs
investigation.
It
is
also
unclear
whether
the
EPRI
or
EPA
models
fully
account
for
the
many
conversion
processes
that
can
occur
in
the
atmosphere
or
the
conversion/
uptake
of
Hg
by
the
forest
canopy.
Both
of
these
processes
would
increase
local
deposition.
Specifically,
it
is
now
well­
documented
that
elemental
Hg
is
converted
to
oxidized
Hg
in
the
presence
of
ozone
and
chloride.
This
is
particularly
important
along
the
eastern
seaboard
where
both
ozone
and
sea
salt
are
high.

Community
Multiscale
Air
Quality
(
CMAQ)
model.
The
commenter
understood
that
EPA
has
been
developing
CMAQ
over
a
number
of
years
as
a
potential
replacement
for
REMSAD.
However,
the
commenter
stated
that
the
CMAQ
is
not
yet
in
the
public
domain
and
has
not
been
externally
peer­
reviewed
to
the
extent
it
must
be
prior
to
its
adoption
by
EPA.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
For
discussion
of
the
air
quality
modeling,
please
see
chapter
8
of
the
RIA
and
EPA's
Technical
Support
Document
for
the
Final
Clean
Air
Mercury
Rule:
Air
Quality
Modeling.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
agrees
with
EPA's
call
for
increased
9­
197
understanding
about
how
dry
Hg
deposition
adds
to
the
total
ecosystem
deposition.
Figure
D1
shows
a
new
set
of
Hg
deposition
data
obtained
from
sedimentary
cores
representative
of
the
past
11,000
years
in
Elk
Lake
in
Minnesota.
These
data
might
serve
as
an
important
benchmark
in
wet
and
dry
depositions
under
a
very
wide
range
of
meteorological
and
climatic
conditions
as
well
as
a
variety
of
Hg
sources
(
for
example,
Hg­
enriched
dusts
and
sands
from
nearby
Nebraska
sand
hills
or
Hg
from
local
and
regional
forest
fires)
for
EPA's
REMSAD
and
CMAQ
models
to
demonstrate
both
the
correctness
and
robustness
of
their
atmospheric
transport,
chemistry
and
deposition
modules.
Measurements
of
Hg
over
the
past
11,000
years
in
Elk
Lake,
MN
show
that
today's
Hg
level
is
neither
exceptional
nor
alarming.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
For
discussion
of
the
air
quality
modeling,
please
see
chapter
8
of
the
RIA
and
EPA's
Technical
Support
Document
for
the
Final
Clean
Air
Mercury
Rule:
Air
Quality
Modeling.
Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
noted
that
EPA
was
the
major
co­
funder
of
a
technical
workshop
on
Mercury
Monitoring
and
Assessment
held
in
Pensacola,
Florida,
on
September
14­
17,2003.
The
Workshop
was
also
co­
funded
by
EPRI
and
sponsored
by
the
Society
of
Environmental
Toxicology
and
Chemistry
(
SETAC).
Participants
included
32
Hg
scientists
from
academia,
industry,
government,
and
nonprofit
organizations.
The
purpose
of
the
workshop
was
to
identify
a
variety
of
environmental
and
ecological
indicators
to
assess
trends
due
to
changes
in
Hg
emissions
and
fluxes
to
the
environment.
Participants
at
the
workshop
were
also
charged
with
the
preliminary
development
of
a
network
of
monitoring
stations
with
emphasis
on
North
America
in
order
to
evaluate
the
effects
of
Hg
regulatory
actions
being
implemented
by
Canada
and
the
U.
S.

Two
products
from
this
workshop
will
be
published
in
2005.
A
paper,
Monitoring
the
Environmental
Response
to
Changing
Atmospheric
Mercury
Deposition
(
Mason
et.
al.,
in
press),
is
scheduled
for
publication
in
Environmental
Science
and
Technology
in
its
January
issue.
In
addition,
a
book,
Mercury
Monitoring
and
Assessment
(
Newman
et.
al.,
in
preparation),
will
be
published
by
SET
AC
Publications
later
this
year.
This
major,
EPA­
initiated
effort
is
not
mentioned
in
EPA's
proposed
revised
benefits
assessment.
Since
the
direct
monitoring
of
Hg
impacts
on
human,
wildlife,
and
ecosystem
health
would
provide
the
most
irrefutable
evidence
of
the
success
(
or
lack
of
success)
of
EPA's
regulatory
strategy,
this
initiative
should
be
given
a
primary
role
in
EPA's
benefits
assessment.

The
Relationship
of
Reductions
in
Air
Deposition
of
Mercury
to
Methylmercury
in
Fish
Tissue
9­
198
EPA's
benefits
analysis
requires
that
it
quantify
how
a
reduction
in
Hg
emissions
to
the
air
translates
into
reductions
of
MeHg
in
fish
tissue.
The
most
important
thing
for
EPA
to
recognize
is
that
a
reduction
in
air
emissions
of
Hg
cannot
be
expected
to
result
in
a
reduction
in
fish
tissue
Hg
in
a
manner
that
is
predictable
by
a
generally
applicable
rule
 
whether
linear,
sub­
linear,
or
time­
dependent.
The
entire
array
of
physical,
chemical,
and
biological
processes
that
influence
the
conversion
of
elemental
Hg
in
the
air
to
MeHg
in
fish
tissue
is
complex.
Moreover,
the
relative
importance
of
these
factors
differs
on
a
site­
specific
basis.

EPA
proposes
to
use
a
steady
state
source­
receptor
model
(
Mercury
Maps
or
MMaps)
as
a
tool
to
predict
the
biological
responses
(
changes
in
Hg
content)
to
reductions
in
emissions
of
Hg
from
coal­
fired
utility
boilers.
As
explained
in
more
detail
below,
Mercury
Maps
should
only
be
used
as
a
preliminary
screening
tool
whose
results
must
be
groundtruthed
by
subsequent,
more
definitive
investigations.

Additionally,
any
screening
tool
must
recognize
that
only
Hg
deposited
directly
to
a
water
body
(
or
flowing
overland
without
reacting
with
soil)
is
readily
and
quickly
incorporated
into
biota.
Mercury
deposition
to
uplands
does
not
readily
migrate
to
waterbodies
but
instead
becomes
incorporated
into
the
humic
matter
of
soil.
While
some
very
small
amount
of
this
Hg
in
soil
may
eventually
leach
to
a
water
body,
such
a
process
occurs
over
decades,
so
that
any
newly
deposited
Hg
has
an
insignificant
effect
on
the
total
amount
of
Hg
that
has
already
accumulated
in
soil
over
thousands
of
years.
Any
modeling
process
that
EPA
uses
must
treat
deposition
directly
to
the
lake
surface
differently
from
deposition
to
the
surrounding
uplands.

The
Florida
Mercury
Report
Does
Not
Demonstrate
that
Changes
in
Air
Emissions
Result
in
Rapid
Changes
in
Fish
Tissue
Mercury
EPA
should
not
give
undue
weight
to
a
study
in
Florida
that
shows
large
reductions
in
fish
tissue
Hg
in
the
aftermath
of
reductions
in
air
emissions.
For
one
thing,
the
Everglades,
where
this
study
was
conducted,
are
a
unique
ecosystem,
and
results
from
the
Everglades
cannot
be
extrapolated
to
other
locales.

In
November
2003,
the
Florida
Department
of
Environmental
Protection
combined
two
earlier
Hg
reports
into
a
single
document
that
the
commenter
will
call
the
"
Florida
Study".
This
report
has
been
widely
publicized
and
widely
misinterpreted.
It
does
not
show
that
reductions
in
air
deposition
will
rapidly
be
followed
by
reductions
in
fish
tissue
Hg,
and
certainly
not
outside
the
unique
environment
of
the
Everglades.

Analyses
of
the
Florida
Study
by
EPRI
reveal
the
following
important
facts:

°
The
Hg
emissions
released
by
municipal
and
medical
waste
incinerators
are
different
from
those
released
by
power
plants.

°
There
are
two
major
forms
of
Hg
in
emissions
 
oxidized
(
ionic),
which
is
water
9­
199
soluble,
and
elemental,
which
is
not
water
soluble.

°
Most
incinerator
Hg
is
in
the
water­
soluble
form,
whereas
the
form
of
Hg
released
from
power
plants
depends
upon
many
factors
such
as
the
type
of
coal
being
burned.
Recent
research
has
shown
that
most
of
the
Hg
released
by
utilities
(
at
least
60
percent)
is
the
non­
water­
soluble
elemental
form
and
that
a
significant
amount
of
the
remainder
converts
to
this
non­
soluble
form
shortly
after
leaving
the
stack.

°
The
form
of
Hg
emitted
is
critical,
because
oxidized
Hg
can
be
washed
into
local
rivers,
lakes,
and
streams
by
rainfall,
whereas
elemental
Hg
is
carried
away
by
wind
and
enters
the
global
Hg
cycle.

°
The
Florida
Everglades
Study
represents
a
unique
ecological
system
not
typical
of,
and
in
fact
strikingly
different
from,
other
US
waterways.
Thus,
the
results
from
this
study
are
not
necessarily
applicable
to
other
areas.

°
The
Everglades
are
in
a
tropical
zone
(
no
seasons),
the
water
is
shallow,
and
the
bottom
sediments
are
much
different
from
those
in
other
water
bodies
throughout,
the
U.
S.
Other
waterways
also
have
different
levels
of
acidity,
biological
activity"
dissolved
oxygen,
and
turbidity.
These
differences
can
dramatically
affect
Hg
cycling
and
uptake
by
biological
organisms.
Thus,
it
is
unlikely
that
the
changes
in
Hg
in
fish,
both
the
amount
and
the
rate
of
decline,
would
be
observed
in
other
U.
S.
waters.

°
The
claim
that
changes
in
Hg
emissions
result
in
rapid
changes
in
fish
Hg
content
is
not
supported
by
the
data
or
findings.

°
The
Florida
Study
assumes
that
Hg
deposition
in
the
Everglades
originates
only
from
local
sources
(
primarily
incinerators
and
power
plants).
However,
data
measurements
and
long­
range
transport
modeling
indicate
otherwise.

°
In
fact,
despite
decreases
in
Hg
emissions
from
incinerators,
no
deposition
data
exist
spanning
the
reduction
period,
and
other
regional
and
global
changes
were
occurring
during
the
same
period.
Therefore,
it
is
not
possible
to
determine
how
much,
if
any,
the
amount
of
Hg
being
deposited
in
the
Everglades
has
changed.

°
Indeed,
both
EPA
and
EPRI
have
modeled
Hg
transport
and
concluded
that
over
60
percent
of
Hg
currently
deposited
in
Florida
originates
outside
the
U.
S.
Guentzel
et
al.
(
200
I)
hypothesized
that
long­
range
(
global)
transport
of
reactive
gaseous
Hg
(
RGM),
coupled
with
strong
thunderstorm
activity
during
summer
months,
represents
>
50
percent
of
the
Hg
deposition
in
southern
Florida.
58
The
authors
highlight
the
importance
of
non­
atmospheric
loading
factors
and
global
sources
of
Hg:
9­
200
°
The
contrast
between
uniform
Hg
deposition
and
geographical
"
hot
spots"
in
fish
Hg
concentrations
from
the
Everglades
region
further
suggests
that
aquatic/
terrestrial
Hg
cycling
processes,
rather
than
atmospheric
source
strength,
are
responsible
for
the
hot
spots...
.
From
our
analysis
of
the
data,
we
conclude
that
significant
reduction
in
rainfall
Hg
deposition
over
the
Florida
Everglades
will
likely
require
reductions
in
local
and
global
Hg
emissions.

°
In
addition,
not
all
the
change
in
fish
Hg
content
can
be
attributed
to
the
unknown
change
in
deposition
because
other
factors
that
mediate
the
ecosystem
response
to
Hg
load
have
also
changed.
Several
theories
have
been
suggested
involving
changing
nutrient
levels
and
water
flows
in
the
Everglades.
Further
research
is
needed
to
understand
this
situation.

°
The
atmospheric
transport
model
used
by
the
State
of
Florida
to
estimate
Hg
deposition
has
limitations.

°
The
model
does
not
incorporate
chemical
reactions
in
the
atmosphere.
It
also
does
not
include
global
sources
of
Hg,
only
local
emissions.
Thus,
it
cannot
effectively
simulate
the
actual
Hg
deposition.

°
EPRI's
recent
research
findings
indicate
that
power
plant
Hg
controls
would
not
significantly
change
the
amount
of
Hg
contained
in
fish,
or
the
human
exposure
to
it.

°
In
early
2003,
EPRI
completed
a
comprehensive
study
of
U.
S.
power
plant
Hg
emissions,
potential
Hg
controls,
and
responses
of
fish
to
changes
in
Hg
in
their
habitat
waters.
The
results
showed
that
reducing
Hg
emissions
from
power
plants
by
approximately
50
percent
would
result
in
a
reduction
of
Hg
in
fish
of
about
1
½
percent.
This
study,
combining
atmospheric
data
and
models,
fish
consumption
information
from
U.
S.
government
studies,
and
an
economic
model
of
the
U.
S.
utility
industry,
relies
on
more
recent
information
than
the
two­
year­
old
Florida
study
report
released
on
November
6,
2003.

The
Steady­
State
Linear
Relationship
Between
Air
Deposition
and
Methylmercury
Concentrations
in
Fish
as
Reflected
in
the
Mercury
Maps
Model
Is
Not
Generally
Appropriate
EPA
requests
comment
on
the
use
of
the
steady­
state
linear
relationship
between
air
deposition
and
MeHg
concentrations
in
fish,
as
reflected
in
the
MMaps
model.
The
MMaps
model
was
developed
by
EPA's
Office
of
Water
to
assess
what
levels
of
reduction
in
Hg
deposition
would
be
needed
to
achieve
the
fish
Hg
criterion
of
0.3
ppm.
It
was
intended
to
apply
only
to
watersheds
where
the
principle
source
of
Hg
is
atmospheric
deposition
and
where
there
is
no
known
land­
based
source
of
Hg
discharge
into
the
waterways.

The
MMaps
model
is
simplified
compared
to
other
models
and
for
that
reason
can
be
9­
201
applied
over
a
broader
geographic
scale.
But
it
has
limitations,
among
which
are
the
following:

°
The
model
uses
the
arithmetic
average
of
all
fish
Hg
data
in
each
Hydrologic
Unit
Code
(
HUC)
watershed.
This
averaging
may
blur
the
substantial
differences
in
water
chemistry
and
fish
Hg,
both
spatially
and
temporally,
that
are
known
to
exist
within
a
single
watershed.
An
alternative
approach
may
be
to
associate
the
fish
Hg
level
with
both
the
deposition
loads
as
well
as
other
relevant
water
chemistry
parameters
(
pH;
nutrient
levels;
extent
of
anoxia
in
waterbody;
water
temperature;
etc.).
This
may
provide
a
better
prediction
of
the
responses
in
specific
waterbodies
as
opposed
to
making
a
prediction
of
the
fish
Hg
response
for
an
entire
HUC
watershed.
Further,
the
analysis
should
be
confined
to
a
particular
species
of
fish,
preferably
with
a
similar
size
or
weight
range.

°
The
output
of
MMaps
is
highly
dependent
on
the
extent
of
state­
specific
fish
tissue
data
records.
For
states
that
have
a
relatively
long
record
offish
Hg
levels
from
a
variety
of
water
body
types,
the
accuracy
of
the
true
existing
Hg
levels
is
relatively
high.
For
states
that
have
monitored
Hg
levels
in
fish
only
recently,
or
sporadically,
the
comparison
of
"
average"
HUC
fish
tissue
Hg
to
EPA's
MeHg
fish
tissue
criterion
incorporates
high
uncertainty.
EPA's
summary
of
state
fish
tissue
monitoring
data
for
1990­
95
indicates
considerable
state­
to­
state
variation
in
the
number
of
water
bodies
sampled,
the
number
of
total
collections,
the
species
sampled
for,
the
number
of
fish
analyzed,
and
the
frequency
of
monitoring.
The
report
also
indicates
the
distribution
of
species
sampled
for
Hg
levels.
Two
sport
fish
species
(
largemouth
bass
and
channel
catfish)
were
sampled
more
extensively
than
any
other
species.
Only
two
states
(
Kansas
and
Washington
State)
do
not
report
Hg
levels
for
largemouth
bass.
EPA
should
consider
standardizing
MMaps
by
using
Hg
analysis
data
for
two
species
only:
largemouth
bass
and
channel
catfish.
A
standardization
of
fish
length
or
age
would
further
increase
the
accuracy
of
what
watersheds
actually
may
have
fish
that
exceed
the
human
health
fish
tissue
criterion.

°
The
EPA
report
uses
the
modeling
results
from
the
Everglades
TMDL
to
help
corroborate
the
assumption
of
a
linear
response.
However,
there
are
two
concerns,
as
noted
above.
First,
the
Everglades
TMDL
assumed
all
the
fish
changes
were
caused
by
local
emission
changes
and
did
not
consider
other
regional
and
global
changes
or
any
local
ecosystem
changes
that
would
mediate
that
assumption.
Thus,
the
actual
reduction
in
fish
Hg
due
to
atmospheric
deposition
reduction
in
the
U.
S.
would
be
less
than
predicted
by
Mmaps
if
the
simulated
changes
in
Hg
deposition
from
changes
in
U.
S.
emissions
do
not
account
for
global
sources.
Second,
the
intercept
was
considered
by
the
TMDL
researchers
to
be
due
to
the
fact
that
sediment
Hg
is
recycled
to
the
water
column
by
macrophyte
roots.
The
redistribution
of
Hg
from
sediments
may
be
an
important
source
to
the
water
column
in
some
waterbodies.
Matty
and
Long
found
that,
in
the
Great
Lakes,
the
most
important
processes
influencing
levels
of
Hg
in
sediments
(
decay
of
organic
matter,
iron
and
manganese
redox
cycling,
exchange
of
Hg
from
porewater
to
sediments)
would
result
in
the
long­
term
retention
of
Hg
near
the
sediment­
water
interface.
This
Hg
would
be
available
for
assimilation
by
benthic
organisms.
This
source
(
legacy
sediment
Hg)
would
not
be
influenced
by
cutbacks
in
atmospheric
deposition.
The
TMDL
report
also
stated
9­
202
that
the
intercept
is
partly
a
function
of
the
length
of
simulation
time
 
the
longer
the
time,
the
smaller
the
intercept.

°
The
assumptions
that
are
critical
in
causing
the
model
to
exhibit
a
linear
response
to
air
deposition
were
discussed
in
the
Everglades
TMDL
report
but
were
not
discussed
in
the
EPA
report.
These
assumptions
include:

°
Methylation
was
allowed
to
occur
only
in
sediment,
based
on
porewater
Hg(
II)
concentration.
Large
stratified
reservoirs
and
lakes
with
anoxic
zones
can
have
methylation
in
the
water
column.
Thus,
the
Everglades
system
is
not
representative
of
all
types
of
waterbodies.

°
Geochemical
factors
that
could
influence
the
Hg(
II)
concentration
in
the
porewater
such
as
cinnabar
formation
were
not
included.
If
such
factors
are
controlling
the
Hg(
II)
concentration,
then
a
reduction
in
deposition
load
may
not
cause
a
linear
change
in
Hg(
II)
concentration.

°
Methylation/
demethylation
rates
were
limited
only
by
Hg
substrates.
Other
factors
such
as
carbon
supply
are
important
and
can
influence
the
rates.
Watras
et.
al.,
studied
15
lakes
in
northern
Wisconsin,
and
found
relatively
low
concentrations
of
sediment
MeHg.
The
authors
suggested
that
a
high
rate
of
demethylation
accounted
for
this
observation.
Based
on
recent
work
by
Marvin
DiPasquale
et.
al.
(
2000),
demethylation
rates
become
nonlinear
at
high
concentrations
of
Hg.
This
latter
possibility
was
not
considered
in
the
Everglades
TMDL,
although
it
may
be
less
important
in
that
system
than
in
waterbodies
with
natural
elevated
Hg.

°
The
model
is
based
on
a
uniform
linkage
between
atmospheric
deposition
of
Hg
and
the
amount
that
reaches
a
waterbody
for
eventual
uptake
by
fish.
This
type
of
analysis
does
not
consider
the
effect
of
varying
retention
based
on
different
types
of
land
uses
and
the
effect
of
canopy
type
on
dry
deposition.
The
actual
response
to
the
same
decrease
in
atmospheric
load
would
vary
across
watersheds
because
the
proportion
of
the
load
reaching
the
waterbody
would
not
be
the
same.

°
The
apparent
linear
response
of
fish
to
decreases
in
atmospheric
loading
does
not
seem
compatible
with
a
hypothesis
of
differing
methylation
efficiency
in
waterbodies.
Other
factors
such
as
temperature
are
important
in
controlling
fish
metabolism,
which
then
influences
the
response
of
fish
to
a
given
MeHg
concentration.
A
more
detailed
comparison
of
fish
data
with
wide
geographic
coverage
to
the
Hg
deposition
data
may
reveal
that
the
response
is
not
as
linear
as
thought.

°
Variability
in
the
fish
data
could
be
used
to
derive
an
estimate
of
the
uncertainty
in
fish
response
to
any
l
ad
.
cutbacks.
The
assessment
of
variability
in
an
explicit
form.
allows
policy
makers
to
determine
whether
small
changes
in
fish
tissue
Hg
as
a
result
of
changing
deposition
loads
will
be
masked
by
the
inherent
variability
of
the
data
and
so
may
be
9­
203
unmeasurable
or
even
indiscernible.
Due
to
multiple
factors
such
as
fish
species,
age,
size,
and
changes
in
diet
during
their
lifetime,
fish
data
for
a
given
waterbody
are
extremely
variable.

°
The
fish
data
set
could
be
extended
to
include
other
available
data,
particularly
to
close
the
data
gap
in
several
of
the
western
states,
where
no
geo­
referenced
fish
data
were
presented
in
Mercury
Maps.

°
EPA
acknowledges
the
need
for
higher
resolution
modeling
in
order
for
predictions
of
fish
Hg
changes
to
have
some
accuracy:

°
Estimates
of
percent
air
deposition
reductions,
by
watershed,
as
generated
from
a
regional
air
deposition
model,
would
be
needed
to
predict
fish
concentration
changes.

In
summary,
the
commenter
believed
that
the
scientific
knowledge
of
Hg
source
and
receptor
processes
should
compel
EPA
to
use
MMaps
as
a
preliminary
screening
tool
only,
subject
to
verification
by
watershed­
specific
information.
All
in
all,
the
key
assumptions
of
MMaps
(
all
Hg
from
atmospheric
sources
and
equilibrium
conditions
for
Hg
levels
in
fish
and
other
compartments)
make
the
predictive
analysis
highly
sensitive
to
variable
watershed
processes,
physical
and
chemical
factors
affecting
methylation,
and
biological
interactions.
All
of
these
factors
are
known
to
control,
or
influence,
Hg
cycling
and
bioavailability.

An
Evaluation
of
the
EPA's
Assumed
Linear
Relationship
Between
Changes
in
Atmospheric
Emissions
and
Resulting
Fish
Tissue
Mercury
Concentrations­
The
Great
Lakes
The
commenter
stated
that
there
is
a
considerable
amount
of
information
on
Hg
sources
to
the
Great
Lakes,
as
well
as
Hg
deposition,
rates
of
sediment
accumulation,
and
measured
levels
in
Great
Lakes
fish.
Using
this
information,
one
can
evaluate
the
key
assumptions
of
the
linear
source­
receptor
response
by
comparing
the
long­
term
(
and
new)
information
on
the
Hg
in
the
Great
Lakes,
against
the
predictions
inherent
in
the
linear
model.

1.
Sources
of
Hg
and
deposition
to
the
Great
Lakes
Cohen
et.
al.,
modeled
the
total
annual
deposition
of
Hg
to
the
Great
Lakes,
and
the
relative
contributions
by
specific
sources
(
industry
sector,
U.
S.
vs.
Canadian
sources).
They
estimated
that
the
annual
atmospheric
deposition
of
Hg
to
Lake
Michigan
was
highest
(
750
kg/
yr),
followed
by
Lakes
Superior,
Erie,
and
Huron
(
425­
490
kg/
yr),
and
Lake
Ontario
(
220
kg/
yr);
however,
current
and
historic
additions
of
Hg
are
much
greater
than
atmospheric
deposition
in
the
case
of
Lake
Superior.
In
an
earlier
publication,
Shannon
and
Voldner
reported
estimates
of
annual
deposition
to
the
Great
Lakes.
Lake
Erie
and
Lake
Michigan
had
the
highest
estimated
deposition
(
728
1,012
kg/
yr),
followed
by
Lake
Superior.
Lake
Ontario
had
the
lowest
estimated
annual
deposition
(
297
kg/
yr).
Interestingly,
the
authors
also
found
that
the
estimated
annual
rate
of
Hg
volatilization
from
all
lakes
(
2.3­
13.7
t/
yr)
was
within
the
range
of
total
Hg
loading
to
all
lakes
9­
204
(
4.7
t/
yr).

2.
Sediment
Hg
levels
in
the
Great
Lakes
In
a
recent
publication,
Marvin
et.
al.,
reported
on
long­
term
sediment
Hg
levels
in
the
Great
Lakes.
Based
on
the
most
recent
surveys,
Lake
Huron
had
the
lowest
sediment
Hg
levels.
The
western
basin
of
Lake
Erie
had
the
second
highest
sediment
Hg
levels,
while
Lake
Ontario
had
the
highest
levels.
These
Hg
level
patterns
would
not
be
expected
based
on
total
atmospheric
load
(
deposition)
estimates.
If
annual
deposition
of
Hg
alone
dictated
sediment
Hg,
the
highest
Hg
levels
would
be
expected
in
Lake
Michigan,
while
the
lowest
sediment
Hg
levels
would
be
expected
in
Lake
Ontario.
The
authors,
however,
clearly
pointed
out
the
differences
in
Hg
sources
to
each
of
the
Great
Lakes.
While
estimates
indicate
Lake
Superior
receives
most
of
the
external
Hg
loading
from
atmospheric
sources,
the
relatively
high
sediment
Hg
levels
in
Lake
Ontario
are
due
to
localized
(
major
urban)
sources,
and
Hg
loads
coming
from
the
Niagra
River.
Clearly,
for
the
Great
Lakes,
Hg
deposition
information
alone
cannot
be
used
to
predict
resulting
comparative
sediment
levels.
The
authors
indicate
that
sediment
Hg
levels
have
declined
drastically
across
the
Great
Lakes
since
the
1960s:
lakewide
decreases
in
mean
sediment
levels
ranged
from
25
percent
(
Lake
Ontario)
to
80
percent
(
Lake
Huron).

3.
Mercury
levels
in
Great
Lakes
fish
If
EPA's
linear
source­
receptor
response
assumption
were
valid,
then
one
would
expect
that
Hg
levels
in
Great
Lakes
fish
would
mirror
comparative
deposition
rates,
when
compared
across
identical
species
and
age
classes.
The
Canadian
Department
of
Fisheries
and
Oceans
summarized
information
on
long­
term
Hg
level
trends
for
two
species
sampled
in
all
of
the
Great
Lakes:
rainbow
smelt
and
lake
trout.
Mean
concentrations
for
the
years
1977­
1995
were
presented.
The
lowest
Hg
levels
are
found
in
lake
trout
from
Lake
Erie
 
(
average
concentration
during
1990­
1995
(
0.6
ppm);
lake
trout
from
Lake
Ontario
had
the
second
lowest
mean
concentration
(
0.8­
0.9
ppm),
and
lake
trout
from
Lakes
Superior
and
Huron
had
the
highest
mean
Hg
levels
(
1.2­
1.3
ppm).
For
smelt,
once
again
Lake
Erie
samples
contained
the
least
amount
of
Hg
(
0.2
ppm),
Lake
Ontario
samples
had
the
second
highest
level
(
0.21­
0.25
ppm),
and
Lakes
Huron
and
Superior
fish
samples
had
the
highest
Hg
levels
(
0.4
and
0.55
ppm,
respectively).
Long­
term
Hg
concentration
data
for
two
sentinel
fish
species
in
the
Great
Lakes
indicate,
like
sediment
data,
that
atmospheric
deposition
information
alone
provides
no
useful
information
for
resulting
levels
of
Hg
in
lake
biotic
and
abiotic
compartments.

Factors
Affecting
Methylation
The
factors
affecting
methylation
of
Hg
were
summarized
in
a
2003
report
entitled
"
Implementation
of
EPA's
Methylmercury
Criterion
for
Fish
Tissue,"
by
AMEC
Earth
and
Environmental
and
ENVIRON
with
support
from
the
EPRI.

Formation
of
MeHg
in
aquatic
systems
is
influenced
by
a
number
of
environmental
factors.
While
the
microbial
activity
and
the
concentration
of
bioavailable
Hg
primarily
determine
9­
205
methylation
rates,
parameters
such
as
temperature,
pH,
redox
potential,
and
the
presence
of
inorganic
and
organic
complexing
agents
playa
complex,
yet
poorly
understood,
role
in
the
methylation
process.
The
following
is
a
list
of
some
technical
publications
that
indicate
the
most
important
factors
controlling
Hg
mobility
and
bioavailability:

Microbial
Activity:
It
generally
is
believed
that
anaerobic
sulfate­
reducing
bacteria
are
the
principal
methylators
of
inorganic
Hg
in
both
freshwater
and
estuarine
environments
(
e.
g.,
Gilmour
et.
al.,
1992).
Recent
studies
also
indicate
that
these
same
bacteria
also
are
capable
of
mediating
MeHg
degradation.
Not
all
sulfate­
reducing
bacteria
are
capable
of
Hg
methylation,
and
methylation
rates
are
not
always
correlated
with
sulfate
concentration
or
with
sulfatereduction
rates.
The
efficiency
of
microbial
MeHg
production
appears
to
depend
chiefly
on
the
activity
and
structure
of
the
bacterial
community,
bioavailable
Hg
concentration,
and
the
availability
of
nutrients
and
electron
acceptors
such
as
sulfate
(
Choi
and
Bartha
1994).
According
to
Compeau
and
Bartha
(
1985),
the
methylation
potential
of
sulfate­
reducing
bacteria
is
greatest
in
sulfate­
limiting
environments,
but
at
high
sulfate
concentrations,
sulfide
produced
in
respiration
may
inhibit
methylation
through
the
formation
of
HgS
precipitates
or
charged
Hg­
S
complexes
that
are
not
readily
bioavailable.

Sulfide:
Several
studies
have
reported
that
high
sulfide
concentrations
inhibit
MeHg
formation,
and
an
inverse
relationship
between
sulfide
concentration
and
MeHg
production
in
sediments
and
pore
waters
also
has
been
observed.
On
the
other
hand,
increased
MeHg
production
also
has
been
observed
under
certain
sulfide
concentrations
(
e.
g.,
Craig
and
Moreton
1983).
This
suggests
that,
while
high
concentrations
of
sulfide
can
greatly
reduce
MeHg
production,
methylation
is
not
usually
completely
inhibited
(
Ullrich
et.
at.,
2001).
It
is
generally
believed
that
the
inhibitory
effect
of
sulfide
on
methylation
is
due
to
the
formation
of
insoluble
HgS
precipitates
that
are
not
bioavailable.
However,
high
concentrations
of
dissolved
Hg
observed
in
sulfidic
porewaters
suggests
that
sulfide
may
actually
help
mobilize
Hg
through
the
formation
of
soluble
Hg­
sulfide
complexes.
Sulfide
may
also
affect
methylation
through
the
formation
of
neutral
HgS0
species
that
can
diffuse
readily
through
cell
membranes
(
Benoit
et.
al.,
1999).
On
the
other
hand,
formation
of
charged
polysulfide
complexes
actually
can
decrease
bioavailability,
but
its
effect
on
methylation
is
not
clear.
As
the
primary
pathway
for
methylation
is
by
sulfate­
reducing
bacteria,
more
research
is
needed
to
identify
the
role
of
various
sulfur
species
and
other
parameters
on
MeHg
formation.

Temperature:
Several
studies
have
indicated
that
maximum
methylation
activity
occurs
during
mid­
or
late
summer
(
e.
g.,
Watras
et.
al.,
1995).
Other
studies
have
found
higher
MeHg
concentrations
in
spring
than
in
summer.
While
increased
temperature
can
contribute
to
increased
microbial
activity,
it
also
affects
seasonal
changes
in
productivity/
nutrient
supply,
redox
conditions,
and
demethylation
rates.

pH:
There
has
been
concern
that
low
pH
values
may
lead
to
increases
in
the
production
and/
or
bioaccumulation
of
MeHg
because
elevated
Hg
levels
have
been
observed
from
fish
in
acidified
lakes.
Enhanced
methylation
has
been
observed
in
low­
pH
waters
and
sediments;
however,
this
process
is
dependent
on
the
redox
state
of
the
system
(
in
anaerobic
systems,
acidic
9­
206
pH
lowers
MeHg
production)
and
other
factors.
pH
may
indirectly
affect
methylation
by
altering
the
mobility
and
partitioning
of
Hg
and
MeHg
in
soils,
stimulating
MeHg
production
through
the
addition
of
sulfate
(
in
acid
rain)
and
by
changing
microbial
activity
(
particularly
the
49
sulfatereducing
species)
or
cellular
uptake
of
Hg+
2.
Changes
in
pH
also
can
alter
Hg
speciation
(
e.
g.,
enhanced
production
of
elemental
Hg,
altering
the
binding
of
Hg
to
organic
matter
and
other
ligands),
which
in
turn
can
affect
the
amount
of
ionic
Hg
available
for
microbial
methylation.
Demethylation
rates
are
also
pH­
sensitive,
albeit
to
a
lesser
extent
than
methylation
rates.

Organic
Matter:
The
role
of
organic
matter
in
methylation
also
is
very
complex
and
poorly
understood.
Observed
increases
in
MeHg
concentrations
with
higher
dissolved
organic
carbon
(
DOC)
concentrations
have
been
attributed
to
a
stimulating
effect
of
organic
nutrients
on
microbial
methylation
activity
(
i.
e.,
microbes
utilizing
organic
matter
as
energy
source
when
sulfate
is
limiting).
Direct
abiotic
methylation
of
Hg
by
humic
and
fulvic
acids
(
the
refractory
portions
of
dissolved
organic
matter)
also
could
be
very
important,
particularly
in
wetlands
where
high
generation
of
MeHg
has
been
observed.
This
mechanism
largely
has
been
ignored
and,
to
date,
it
is
not
clear
to
what
extent
abiotic
methylation
contributes
to
MeHg
production
in
organicrich
sediments
and
lake
waters.
It
may
be
hypothesized
that
where
organic
matter
is
labile
and
readily
biodegradable,
it
may
promote
methylation
by
stimulating
microbial
growth,
and
where
the
organic
matter
is
recalcitrant
and
consists
of
high­
molecular­
weight
humic
and
fulvic
acids,
it
may
contribute
to
abiotic
methylation.

Decreased
methylation
has
also
been
observed
at
high
concentrations
of
organic
matter
in
both
natural
systems
and
experimental
studies,
and
it
has
been
suggested
that
DOC
may
strongly
bind
with
inorganic
Hg
at
sulfur­
containing
functional
groups,
rendering
them
unavailable
for
bacterial
methylation.
Even
if
MeHg
forms,
it
may
be
complexed
by
DOC
and,
therefore,
not
available
for
bioaccumulation.
DOC
also
can
compete
with
sulfide
for
Hg
binding
and
favor
the
mobilization
of
Hg
through
the
formation
of
Hg­
DOC
complexes.
In
Hg
binding
with
DOC,
pH
may
play
an
important
role
where
protons
compete
with
metal
binding
sites
in
organic
matter.
Humic
substances,
which
are
recalcitrant,
high­
molecular­
weight
fractions
of
organic
matter,
also
can
reduce
Hg+
2
to
the
volatile
Hg0
species,
both
directly
as
well
as
by
enhancing
the
reduction
rates
in
photochemical
reactions,
thus
reducing
the
Hg
burden
available
for
methylation.

Redox
Conditions:
Even
though
Hg
methylation
occurs
in
both
aerobic
and
anaerobic
conditions
in
the
natural
environment,
methylation
rates
are
highest
in
anoxic
sediments
and
waters,
and
the
stability
of
MeHg
is
greatest
in
anaerobic
environments.
This
may
be
due
to
the
reduced
activity
of
sulfate­
reducing
bacteria
under
aerobic
conditions
and
the
enhanced
degradation
of
MeHg
in
aerobic
conditions.
It
appears
that
anaerobic
methylation
is
predominantly
microbial
in
nature
and,
therefore,
enhanced
by
the
presence
of
organic
matter;
whereas
abiotic
methylation
is
favored
under
aerobic
conditions
and
is
suppressed
by
the
presence
of
organic
matter
(
possibly
due
to
complexation
with
organic
matter
rendering
Hg
unavailable
for
methylation).
Methylmercury
concentrations
usually
are
highest
in
the
moderately
anaerobic
surface
sediments
(
mostly
at
the
oxic­
anoxic
interface)
and
rapidly
decline
with
depth.
Likewise,
in
stratified
lakes
and
estuaries,
MeHg
concentrations
are
usually
highest
at
the
oxic/
anoxic
boundary
layer.
Changes
in
redox
conditions
in
water
column
and
sediment
layers
also
result
in
9­
207
seasonal
variations
in
MeHg
concentrations.
Organic
matter,
nutrients,
pH,
and
sulfides
significantly
influence
the
redox
effects
on
MeHg
production.

Salinity:
The
methylating
activity
in
marine
and
estuarine
sediments
is
usually
lower
than
in
freshwater
sediments,
partly
due
to
salinity
effects.
The
negative
effect
appears
to
be
a
result
of
formation
of
charged
sulfide
complexes
(
from
sulfate
in
sea
salt)
in
seawater
and
charged
Hgchloride
complexes
such
as
HgCl
4
­
2
that
limit
the
methylation
process.
Thus,
estuarine
fish
tend
to
have
lower
MeHg
in
their
tissue
than
comparable
species
in
freshwater
fish
(
Gilmour
and
Riedel
2000).

In
summary,
Hg
methylation
is
primarily
a
microbially
mediated
process,
and
the
precise
mechanism
of
MeHg
formation
still
is
unclear.
Mercury
methylation
and
demethylation
rates
in
aquatic
systems
are
influenced
by
both
the
speciation
and
biochemical
availability
of
Hg
and
by
a
large
number
of
interrelated
environmental
variables,
such
as
biological
activity,
nutrient
availability,
pH,
temperature,
redox
potential,
and
inorganic
and
organic
complexing
agents.
The
importance
of
each
of
these
parameters
and
their
complex
interactions
varies
across
different
ecosystems
and
even
within
the
same
type
of
water
bodies.
Different
mechanisms
of
methylation
may
occur
in
sediments
and
in
water.
Seasonal
variations
in
MeHg
production
appear
to
be
related
to
temperature,
redox
effects,
seasonal
changes
in
nutrient
availability
and
Hg
availability.
Sulfur
speciation
and
dissolved
organic
matter
complexation
are
other
important
factors
that
are
not
well
understood.

Knowledge
Gaps
Despite
the
vast
body
of
literature
on
the
subject
(
348
publications
cited
in
Ullrich
et.
al.,
2001),
we
still
are
unable
to
predict
Hg
methylation
rates
or
the
likely
effects
of
environmental
perturbations
on
methylation
processes
in
natural
systems
due
to
the
complexity
of
the
systems
described
above.
Since
laboratory
studies
look
at
simple
systems
with
few
variables
at
a
time,
it
also
is
difficult
to
directly
compare
the
results
of
the
laboratory
studies
published
to
date
with
the
processes
and
rates
in
the
natural
environment.
Knowledge
gaps
exist
in
the
following
areas:

Biotic
vs.
Abiotic
Methylation:
While
it
widely
is
believed
that
Hg
methylation
is
biologically
mediated,
review
of
literature
by
Ullrich
et.
al.
(
2001)
suggests
that
there
may
be
more
than
one
mechanism
of
MeHg
formation.
Abiotic
methylation,
particularly
that
mediated
by
humic
substances,
could
be
very
important
in
wetlands
and
other
ecosystems,
but
the
significance
of
such
processes
in
natural
environments
is
unknown.
Methylation
vs.
Demethylation:
A
portion
of
MeHg
generated
is
demethylated
by
microorganisms,
photochemical
reactions,
and
other
processes.
Sulfate­
reducing
bacteria,
which
were
considered
to
be
important
methylating
agents,
also
now
are
considered
to
be
active
demethylators.
It
is
not
clear
what
environmental
conditions
cause
these
microbes
to
carry
out
methylation
instead
of
demethylation.

Biomethylation:
Review
of
the
literature
suggests
that
methylation
can
be
caused
by
sulfate­
reducing
bacteria
as
well
as
a
number
of
other
types
of
bacteria
that
have
not
yet
been
identified.
In
the
case
of
methylation
by
sulfate­
reducing
bacteria,
the
optimum
sulfate
9­
208
concentrations
required
for
methylation
vary
widely
between
different
ecosystems
and
are
difficult
to
predict.
For
example,
bacteria
in
estuarine
systems
can
methylate
Hg
at
much
higher
sulfate
concentrations
than
in
freshwater
systems.
In
addition,
since
bacteria
that
methylate
Hg
also
are
capable
of
demethylating,
we
are
unable
to
predict
biomethylation
rates
in
natural
systems.

Role
of
Organic
Matter:
Natural
organic
matter
in
soils,
sediments,
and
water
affect
methylation
in
several
ways.
While
natural
organic
matter
can
provide
a
stimulating
effect
on
bacterial
methylation
in
some
systems,
it
may
promote
abiotic
methylation
in
other
systems
or
inhibit
Hg
methylation
(
due
to
strong
complexation)
under
other
environmental
conditions.
The
exact
role
of
organic
matter
in
a
given
system
often
is
ignored
in
predicting
methylation
rates.
Because
of
the
complex
structure
and
composition
of
organic
matter
and
due
to
the
paucity
of
thermodynamic
data
for
organic
matter
 
Hg
complexes,
the
role
of
organic
matter
on
the
speciation
and
bioavailability
of
Hg
has
not
been
well
described
or
modeled.

Sulfur
Chemistry:
Sulfur
speciation
is
an
important
variable
in
the
methylation
process.
In
addition
to
the
role
of
sulfate
on
the
methylation
process,
reduced
sulfur
can
complex
with
Hg
and
form
charged
or
uncharged
Hg­
sulfide
complexes
determining
whether
or
not
Hg
becomes
available
to
the
microbes
for
methylation.
Various
stoichiometries
of
Hg­
sulfide
complexes
have
only
been
speculated,
and
competitive
reactions
between
sulfide,
organic
matter,
and
Hg
are
not
well
defined.

Synergistic
and
Antagonistic
Effects:
From
previous
discussions
it
is
apparent
that
each
of
the
variables
discussed
above
have
multiple
influences
on
the
methylation
and
demethylation
process.
For
example,
low
concentrations
of
sulfate
can
limit
microbial
methylation,
while
high
concentrations
of
sulfate
can
result
in
the
formation
of
excess
sulfide
concentrations
that
complex
with
Hg
and
inhibit
Hg
methylation.
Some
of
the
above
parameters
can
alter
the
effect
of
other
influencing
factors
on
Hg
methylation.
For
example,
pH
and
redox
can
directly
affect
methylation
and
bioaccumulation
as
well
as
altering
Hg
speciation,
sulfur
chemistry,
and
microbial
activity.
Due
to
the
complex
role
of
anyone
of
the
above
parameters
on
methylation,
it
is
difficult
to
predict
their
combined
effect
in
natural
systems
with
existing
models.
There
are
many
factors
affecting
methylation,
but
the
current
science
is
not
adequate
to
resolve
which
factors
are
most
important
and
allow
models
to
move
towards
a
more
predictive
capability.
Research
into
factors
affecting
methylation
is
ongoing,
however,
with
significant
progress
expected
over
the
next
several
years.

METAALICUS
Project:
Some
of
the
questions
on
the
rates
and
factors
governing
Hg
methylation
may
be
answered
by
the
Mercury
Experiment
to
Assess
Atmospheric
Loading
in
Canada
and
the
U.
S.
(
METAALICUS)
project
currently
underway
at
the
Experimental
Lakes
Area
(
ELA)
in
western
Ontario,
Canada
(
Harris
et.
al.,
2001).
METAALICUS
is
a
multidisciplinary
whole­
ecosystem
experiment
in
which
a
different
isotope
of
Hg
in
the
inorganic
form
(
Hg(
II))
is
added
to
the
upland,
the
wetland,
and
the
lake
surface
to
determine
the
relationship
between
atmospheric
Hg
loading
and
fish
Hg
concentrations.
One
of
the
goals
is
to
determine
how
much
of
the
newly
deposited
atmospheric
Hg
becomes
bioavailable
for
methylation
and
biological
uptake.
9­
209
Implications
of
Knowledge
Gaps
Any
efforts
to
reduce
MeHg
concentration
in
fish
tissue
require
a
clear
understanding
of
the
processes
that
produce
MeHg
and
factors
that
promote
demethylation.
Methylmercury
production
in
aquatic
systems
is
not
a
simple
function
of
total
Hg
concentration
in
the
system.
Rather,
as
discussed
above,
it
is
affected
by
a
number
of
complex,
interrelated
factors,
which
may
result
in
a
nonlinear
relationship
between
total
Hg
and
MeHg.
Since
any
or
all
of
these
(
or
other)
parameters
can
control
methylation,
either
alone
or
in
a
complex
interrelated
process,
ecosystems
respond
differently
to
changes
in
these
parameters
and,
at
present,
there
is
no
simple
way
to
predict
methylation
rates
in
natural
environments.
In
the
Florida
Everglades,
for
example,
contrary
to
conventional
wisdom,
the
percentage
MeHg
increases
from
north
to
south,
opposite
the
gradients
in
nutrient,
sulfate,
and
sulfide
concentrations
(
Gilmour
et.
al.,
1998).
Regulatory
measures,
such
as
reducing
Hg
loading
rates
from
atmospheric
or
point
sources,
will
be
less
successful
in
reducing
Hg
levels
in
fish
without
greater
understanding
of
these
complex
processes.

Marine
and
Farm­
Raised
Species
Because
MMaps
is
designed
to
simulate
natural
freshwater
systems,
EPA
does
not
have
an
appropriate
method
for
assessing
how
a
change
in
Hg
deposition
relates
to
a
change
in
MeHg
in
fish
tissue
found
in
marine
environments
or
farm­
raised
species.

Time
Lag
In
the
NODA,
EPA
points
out
that
MMaps
does
not
account
for
the
time
lag
between
reducing
Hg
deposition
and
reducing
MeHg
concentrations
in
fish.
In
METAALICUS,
newly
deposited
Hg
appeared
to
be
more
available
to
bacteria
to
convert
to
MeHg
than
Hg
that
was
in
the
system
for
longer
periods
of
time
(
historically
deposited
Hg).
EPA
also
observes
that
systems
that
receive
most
of
their
Hg
input
directly
from
the
atmosphere
may
respond
more
rapidly
to
changes
in
emissions
than
those
receiving
significant
inputs
of
Hg
from
the
catchment
area.
EPA
asks
for
information
that
can
be
used
to
extend
or
extrapolate
the
results
of
the
METAALICUS
experiment
to
other
freshwater
systems
and
information
on
Hg
cycling
and
bioavailability
in
coastal
and
marine
ecosystems.

The
findings
of
the
METAALICUS
study,
as
reported
in
the
scientific
literature,
are
valuable
because
they
provide
empirical
information
on
the
relative
importance
of
Hg
sources
to
Hg
cycling
in
the
study
lake
(
UIF).
It
should
be
noted,
however,
that
the
principal
researchers
have
acknowledged
that
caution
be
used
when
extrapolating
the
METAALICUS
results
to
other
watersheds.
Hintelmann
et.
al.
(
2002)
state
that:

This
conclusion
[
importance
of
newly
deposited
mercury
to
lake
cycling
and
little
runoff
from
the
catchment
area]
is
so
far
limited
to
terrestrial
upland
systems
such
as
U1F.
Further
METAALICUS
studies
are
underway
investigating
similar
processes
in
wetlands
and
aquatic
(
lake)
systems,
keeping
in
mind
that
lakes
receive
mercury
via
direct
atmospheric
deposition
as
well
as
runoff.
.
.
the
overall
9­
210
contributions
of
old
versus
new
mercury
to
mercury
in
runoff
and
the
overall
response
time
of
watersheds
to
changes
in
atmospheric
mercury
deposition
will
most
likely
depend
on
the
balance
of
wet
and
dry
deposition
as
well
as
the
fraction
of
rain
events
that
are
large
enough
to
cause
significant
immediate
runoff
of
newly
deposited
mercury.

While
the
METAALICUS
study
suggests
a
relatively
short
time
lag
between
rates
of
Hg
addition
and
lake
compartment
assimilation,
the
time
lag
of
such
a
response
will
likely
be
unique
to
each
watershed,
and
each
water
body
within
a
watershed.
This
is
because
the
factors
that
control
the
mass
loading
and
mobilization
of
Hg
to
water
bodies
are
unique.

Also,
the
quick
response
time
observed
in
METAALICUS
was
observed
only
for
the
Hg
isotope
directly
applied
to
the
lake
surface.
EPA's
screening
model
presently
assumes
that
the
same
quick
and
linear
response
occurs
with
Hg
deposition
to
uplands
as
well
as
water
surfaces.
The
Florida,
METAALICUS,
Scandinavian,
and
all
other
field
observations
demonstrated
quick
responses
(
and
then
nonlinear
or
sub
linear)
only
for
directly
applied
Hg.

EPRI
modeled
the
changes
in
fish
Hg
concentrations
for
four
lakes
(
two
in
Wisconsin,
one
in
Ontario,
one
in
Florida)
following
a
hypothetical
reduction
in
inorganic
Hg
loading
to
the
lakes,
using
an
updated
version
of
D­
MCM.
Different
modeling
scenarios
of
varying
sediment
depth
(
1­
3
cm)
and
exchangeability
of
inorganic
Hg
to
MeHg
(
availability
of
inorganic
Hg
for
methylation)
were
performed.
The
following
table
indicates
the
time
required
for
fish
Hg
concentrations
to
reach
90
percent
of
the
long­
term
steady
state
concentration:

Modeling
assumptions
(
variables)
Lake
response
(
time
required
for
fish
tissue
Hg
at
90
percent
equilibrium
concentration)

Sediment
layer
=
3
cm,
100
percent
inorganic
Hg
available
for
methylation
40­
160
yrs
Sediment
layer
=
1
cm,
100
percent
inorganic
Hg
available
for
methylation
(
Pallette
Lake)
39­
122
yrs
Sediment
layer
=
1
cm,
10
percent
inorganic
Hg
available
for
methylation
23
yrs
The
modeling
analysis
indicates
two
important
results:
first,
the
response
time
between
reductions
in
extemalloads
and
stable
changed
fish
tissue
concentration
is
NOT
instantaneous
(
within
10
years).
Secondly,
key
assumptions
of
within­
lake
processes
(
in
this
study,
two
variables
affecting
Hg
availability
in
sediments)
can
have
a
pronounced
effect
on
the
predicted
timing
of
long­
term
fish
concentration
change.
This
study
provides
important
insights
regarding
EPA's
expectations
and
assumptions
of
ecosystem
response.
In
short,
a
relatively
rapid
response
(
as
appears
to
be
indicated
by
the
METAALICUS
study)
would
only
be
applicable
to
those
types
of
lakes
that
the
study
was
conducted
at
(
northern
temperate,
oligotrophic).
As
indicated
above,
the
technical
literature
is
replete
with
examples
showing
that
non­
atmospheric
load
factors
are
largely
responsible
for
the
mobility
and
bioavailability
of
Hg.
9­
211
Response:

EPA
appreciates
the
commenter's
input
to
the
record.
Please
see
the
RIA.

4.
Step
4:
Fish
Consumption
and
Human
Exposure.
EPA
plans
to
address
the
relationship
between
reductions
in
methylmercury
concentrations
in
fish
tissue
and
reductions
in
human
exposure
through
consumption.
EPA
plans
on
using
the
National
Listing
of
Fish
Advisories,
supplemented
b
the
National
Fish
Tissue
Study,
for
information
on
methylmercury
concentrations
in
fish
and
consumption
data
(
including
women
of
childbearing
age,
children,
subsistence
farmers
and
high­
end
consumers)
to
determine
the
relationship
between
reductions
in
concentrations
in
fish
tissue
and
reductions
in
human
exposure.
EPA
requested
comment
on
whether
the
methylmercury
fish
concentration
or
fish
consumption
rates
used
in
the
Water
Quality
Criterion
could
be
used
for
local,
regional,
or
national
assessments.
EPA
also
requested
data
on
the
usefulness
of
the
fish
consumption
data
provided
by
the
Clean
Air
Task
Force
et
al
(
OAR­
2002­
0056­
3460),
Edison
Electric
Institute
(
OAR­
2002­
0056­
2929),
Electric
Power
Research
Institute
(
OAR­
2002­
0056­
2578),
Forest
County
Potawatomi
Community
(
OAR­
2002­
0056­
2173),
Minnesota
Conservation
Foundation
et.
al.
(
OAR­
2002­
0056­
2415),
and
Southern
Environmental
Law
Center
(
OAR­
2002­
0056­
4222).

Comment:

One
commenter
(
OAR­
2002­
0056­
5422)
said
that
EPA
should
consider
the
loss
of
health
benefits
associated
with
reduced
fish
consumption
due
to
an
overly
conservative
reference
dose
(
RfD)
for
Hg
blood
levels
in
determining
net
health
benefits
due
to
the
CAMR.
The
vast
majority
of
health
studies
have
concluded
that
the
benefits
of
fish
consumption
by
all
segments
of
the
general
population
far
outweigh
any
effects
due
to
blood
Hg
levels
greater
than
EPA's
RfD
and
at
levels
approaching
the
World
Health
Organization
(
WHO)
level
of
concern.
The
use
of
the
RfD
as
the
basis
for
calculating
fish
warning
Hg
levels
has
resulted
in
a
reduction
in
fish
consumption
and
the
related
loss
of
health
benefits
to
the
public.
The
commenter
supported
the
comments
of
the
Center
for
Science
and
Public
Policy
in
this
regard
(
see
OAR­
2002­
0056­
5423).

Response:

Although
EPA
considers
inclusion
of
the
NFTS
data
extremely
valuable
in
providing
additional
coverage
for
the
study
area,
it
is
important
to
note
that
the
majority
of
measured
fish
tissue
concentrations
were
contributed
by
the
NLFA
and
not
by
the
NFTS.
This
fact
partially
addresses
the
commentor's
concerns
(
i.
e.,
the
benefits
analysis
primarily
reflects
NLFA
data
with
a
smaller
relative
contribution
from
the
NFTS
dataset).
However,
several
points
can
be
made
in
response
to
concerns
raised
by
the
commentor
regarding
the
NFTS
data.
Although
NFTS
composites
do
reduce
variability
(
primarily
related
to
fish
size),
because
size
information
is
available
for
many
of
the
entries
in
NLFA,
standardization
using
the
NDMMFT
model
did
have
access
to
variability
data
related
to
size
through
the
NLFA.
The
Great
Lakes
are
not
being
9­
212
included
in
the
primary
benefits
analysis
because
of
greater
uncertainty
in
linking
mercury
deposition
changes
from
power
plants
to
fish
tissue
concentrations
relative
to
lakes
and
rivers.
The
relatively
small
NFTS
dataset
is
offset
to
some
extent
by
inclusion
of
the
larger
NLFA
dataset,
although
concerns
of
fish
tissue
sampling
coverage
(
both
spatially
and
temporally)
do
persist.
For
additional
information
on
fish
tissue
datasets
used
in
the
benefits
analysis,
see
Sections
10
and
14.

EPA
agrees
with
the
commentor
that
NLFA
data
(
when
reflecting
areas
of
increased
fishing
activity)
would
be
preferable
to
randomly
collected
data
for
purposes
of
supporting
a
benefits
analysis.
However,
given
the
patchy
nature
of
the
NLFA
and
the
variety
of
sampling
protocols
used
by
different
states
in
collecting
data
included
in
the
NLFA,
EPA
considers
the
NFTS
data
to
be
very
useful
in
filling
in
gaps
in
coverages
and
in
providing
a
consistent
randomly­
sampled
dataset
to
augment
the
purposively
sampled
data
contained
in
the
NLFA.

As
described
in
other
responses,
the
Agency
has
high
confidence
in
the
RfD
for
methylmercury.
EPA
encourages
the
public
to
vary
the
species
and
sources
of
fish
in
order
to
obtain
the
benefits
of
fish
consumption
while
avoiding
elevated
exposures
to
methylmercury.
The
fish
advisory
developed
jointly
with
the
Food
and
Drug
Administration
emphasizes
the
benefits
of
including
fish
in
a
healthy
diet
while
informing
the
public
on
ways
to
reduce
methylmercury
exposure
(
http://
www.
epa.
gov/
waterscience/
fishadvice/
advice.
html).

Comment:

Commenter
OAR­
2002­
0056­
5475
stated
that
the
EPA
defines
Hg
`
hot
spot'
as
"
a
mercury
deposition
point
dominated
by
utility
plant
contributions
whose
removal
would
result
in
fish
tissue
levels
dropping
from
above
to
below
the
Fish
Tissue
Criterion
of
0.3
ppm."
The
commenter
found
this
definition
to
be
self­
limiting,
implying
no
significant
Hg
impact
on
the
environment
when,
in
fact,
the
emitting
facility
may
cause
a
Hg
problem
without
including
background
Hg
emissions.
This
is
an
absurd
notion
since
it
would
allow
for
any
increment
of
Hg
emissions
from
a
specific
facility
providing
the
background
fish
tissue
Hg
concentration
is
not
below
0.3
ppm.
For
example,
if
the
Hg
fish
tissue
level
for
fish
found
near
a
utility
plant
is
1.0
ppm,
yet
the
fish
tissue
Hg
content
from
background
emission
sources
would
still
be
0.35
ppm
after
removal
of
the
Hg
from
the
nearby
utility
plant,
this
area
would
not
be
considered
a
`
hotspot'
since
the
fish
would
still
remain
over
the
0.3
ppm
concentration.
This
commenter
stated
that
besides
arbitrarily
limiting
the
identification
of
local
Hg
impacts,
this
type
of
definition
fails
to
take
into
account
the
substantial
risk
that
could
be
posed
by
designating
significantly
elevated
Hg
concentrations
as
acceptable.

Response:

EPA
has
addressed
the
hot
spots
issue
in
the
revision
Federal
Register
notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.
9­
213
Comment:

One
commenter
(
OAR­
2002­
0056­
5475)
stated
that
the
inability
to
quantify
a
facility's
Hg
speciation
percentages
on
an
on­
going
basis
supports
its
concern
that
a
cap­
and­
trade
approach
may
be
inappropriate
compared
to
the
standard
MACT
approach.
The
actual
`
hot
spots'
that
could
be
allowed
to
continue
to
exist
as
a
result
of
a
cap­
and­
trade
approach
may
present
unacceptable
health
risks
to
some
of
the
citizens
of
Pennsylvania.

Response:

EPA
appreciates
the
commenters
concerns.
Please
see
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005)
for
a
discussion
of
the
importance
of
speciation
for
mercury
capture.
Also,
please
see
Chapter
7
of
the
Regulatory
Impact
Analysis
for
a
discussion
of
how
we
took
speciation
into
account
in
our
power
sector
modeling
and
see
Chapter
8
for
a
discussion
of
how
we
took
speciation
into
account
in
our
air
quality
and
deposition
modeling.
EPA
has
addressed
the
hot
spots
issue
in
the
revision
Federal
Register
notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5476)
responded
specifically
to
Step
4
of
EPA's
Proposed
Revised
Benefits
Methodology:
Fish
Consumption
and
Human
Exposure.
This
commenter
believes
that
EPA's
assumed
consumption
levels
of
142.4
grams/
day
underestimates
actual
levels
of
fish
consumed.
The
1993
Survey
of
Tribal
Spearers
conducted
by
the
Great
Lakes
Indian
Fish
and
Wildlife
Commission
(
GLIFWC
)
indicates
that
Ojibwe
tribal
members
across
Minnesota,
Wisconsin
and
Michigan
consume
anywhere
from
155.8
to
240.7
grams/
day
in
conjunction
with
fall
spearing.
The
spring
spearing
season
can
lead
to
consumption
rates
anywhere
from
189.6­
393.8
grams/
day.
The
Leech
Lake
Band
of
Ojibwe
Federally
recognized
Tribe
with
MCT
membership
has
reported
that
they
had
determined
that
a
fish
consumption
rate
of
227
grams/
day
is
possible
under
its
treaty­
protected
fish
harvesting
right.
The
GLIFWC
study
also
showed
that
95
percent
tribal
respondents
consumed
at
least
one
meal
per
week
of
the
walleye
caught
during
spearing
and
over
12
percent
ate
more
than
7
meals
per
week.
This
consumption
is
very
seasonal
in
nature,
with
consumption
rate
varying
by
as
much
as
150
grams/
day
between
the
fall
and
the
spring
but
also
has
started
to
show
more
year­
round
harvest
and
consumption,
as
well
as
extended
food
storage
through
freezing.
However,
GLIFWC's
survey
is
only
a
minimum
threshold
since
the
results
are
based
solely
on
the
those
who
have
participated
in
the
survey
for
some
for
traditional
gatherers,
these
numbers
may
be
higher
since
more
traditional
gatherers
might
not
respond
in
a
survey
but
are
likely
to
consume
more
than
the
highest
numbers
the
survey
participants
have
reported
in
this
survey.

The
1993
survey
reveals
that
the
average
meal
size
may
differ
widely
among
groups.
EPA
9­
214
assumes
an
average
meal
size
of
6
ounces,
or
about
170
grams.
However,
GLIFWC
finds
that
Tribal
members
responding
to
the
survey
and
exercising
their
Fishing
rights
tend
to
eat
an
average
meal
ranging
from
13­
27
ounces,
or
about
369­
766
grams;
this
range
being
only
a
minimum.

Mercury
levels
in
fish
caught
and
eaten
locally
may
exceed
levels
found
in
commercially
available
fish
or
shellfish.
U.
S.
Health
and
Human
Services
and
EPA
data
show
the
commercially
important
fish
like
tuna,
shrimp,
salmon,
and
catfish
can
range
in
concentrations
from
0.01­
0.35
ppm.
But
recent
EPA
data
for
freshwater
fish
show
that
concentrations
for
important
species
like
walleye,
bass,
trout,
pike,
and
perch
can
vary
from
0.25­
1.03
ppm.
This
study
further
shows
that,
in
a
representative
sampling
of
fish
from
U.
S.
lakes,
80
percent
of
predator
fish
levels
exceeded
US
EPA's
safe
limit
of
0.13
ppm
for
women.
Fifty­
five
percent
of
all
freshwater
fish
(
predatory
and
non­
predatory)
sampled
exceeded
this
level
and
66
percent
of
all
fish
sampled
exceeded
US
EPA's
safe
limit
for
children
under
three.
By
contrast,
MCT
used
a
0.05
ppm
trigger
level
for
a
1
meal/
week
consumption
advisory
for
sensitive
populations.

In
all
instances,
the
numbers
given
above
exceed
EPA's
assumed
levels
of
consumption
and
Hg
content,
sometimes
by
large
amounts.
In
further
support
of
the
commenter's
viewpoint,
EPA's
document
Fish
Consumption
and
Environmental
Justice:
A
Report
Developed
from
the
National
Environmental
Justice
Advisory
Committee
Meeting
of
December
3­
6,
2001
(
2002
revised)
states
that
although
EPA's
numbers
are
an
improvement
over
previous
figures,
they
do
not
address
consumption
at
the
highest
potential
rates.
The
commenter
urges
EPA
to
take
this
new
information
into
account
when
reviewing
data
about
human
exposure.

Both
the
EPA
and
the
FDA
have
addressed
Hg
in
fish
tissue,
but
neither
has
done
anything
to
address
Hg
in
other
food
sources
such
as
wild
rice,
moose,
and
wild
birds.
According
to
this
commenter,
Hg
levels
in
some
wild
ducks
occur
at
the
same
levels
as
in
fish
tissue.
Although
these
results
are
from
only
a
limited
number
of
ducks
and
follow­
up
studies
are
needed,
this
is
disturbing
information
that
EPA
may
not
be
aware
of.
Because
moose,
ducks,
and
other
animals
eat
primarily
water
plants,
they
are
vulnerable
to
the
effects
of
Hg
poisoning.
EPA
does
not
attempt
to
address
cumulative
effects
of
toxic
exposures
in
people
who
consume
large
quantities
of
other
natural
resources
(
e.
g.,
venison,
moose,
bear,
waterfowl,
wild
rice,
blueberries).
An
analysis
of
local
fish
tissue
samples
typical
of
those
consumed
by
the
commenter
were
sampled,
and
commenter
consumption
advisories
were
set
accordingly.
For
other
MCT
component
Bands
such
as
the
Mille
Lacs
Band
of
Ojibwe
Indians,
the
commenter
has
had
to
rely
on
those
advisories
set
by
MCT
and
those
set
by
the
State
of
Minnesota.
Sensitive
populations
are
advised
to
eat
no
more
than
one
meal
per
month
of
most
fish
species,
even
if
care
is
taken
to
eat
only
the
smaller
fish
of
the
species.
For
those
fishing
for
subsistence
or
cultural
practice,
this
is
a
ridiculously
small
amount
of
fish.
It
is
clear
that
most
Band
members
are
eating
amounts
in
excess
of
this
recommended
level
of
consumption.
The
commenter
does
not
believe
this
issue
and
the
issue
of
persistence
of
toxic
hazards
created
in
the
environment
due
to
past
weak
or
neglected
resource
protection
were
addressed
in
EPA's
analysis.

The
stationary­
source
industries,
such
as
the
electric
utility
and
steam
generating
units,
should
not
have
the
role
to
tell
the
commenter
(
via
the
IPM
model)
at
what
level
standards
should
9­
215
be
set
so
they
can
deliver
electricity
to
the
commenter
while
fulfilling
regulations
at
the
least
cost
to
themselves.
It
is
up
to
EPA
to
determine
how
much
Hg
can
be
allowed
in
the
environment
and
for
utilities
to
use
their
business
ingenuity
to
determine
how
they
can
best
meet
the
standards
EPA
has
set.
Likewise,
EPA
should
not
tell
the
commenter
how
many
and
what
type
of
fish
can
be
consumed.
Instead,
the
commenter
should
be
able
to
tell
EPA
what
its
consumption
levels
are
and
EPA
should
make
the
fish
safe
for
the
commenter
at
those
levels,
preferably
safe
at
any
level.
If
this
precedence
is
set,
soon
EPA
will
be
calling
upon
the
commenter
to
limit
the
amount
of
air
it
can
breath
and
water
it
can
drink.
Limiting
consumption
of
an
otherwise
healthy
food
source
is
not
the
answer.

The
newspaper
article
"
Mercury's
Dangers
Persist"
(
Milwaukee
Journal
Sentinel,
Section
G1:
April
12,
2004)
reported
that
even
when
people
are
aware
of
the
dangers
of
eating
fish
from
local
waters,
they
often
ignore
the
warnings.
Likewise,
the
commenter
believes
that
many
indigenous
peoples
are
unlikely
to
stop
a
subsistence­
based,
culturally
rich
tradition
even
though
concentrations
and
number
of
toxic
contaminants
continue
to
increase.
Despite
warnings,
some
of
these
people
will
continue
to
fish
and
assume
the
risk
of
possibly
suffering
from
ill
health
effect
from
toxins
or
else
go
hungry.
Since
Hg
can
be
neither
tasted
nor
smelled
in
fish
meat,
this
may
embolden
some
consumers
to
eat
more
than
what
is
recommended
as
being
safe.

Comments
submitted
by
Electric
Public
Research
Institute
(
EPRI)
(
Electric
Public
Research
Institute,
US
EPA
Document
ID
No.
OAR­
2002­
0056­
2578,
June
26,
2004)
addressing
fish
consumption
rates
of
tribal
people
do
not
appear
to
be
accurate.
Since
EPRI
favors
less
stringent
control
options
than
the
commenter
does,
it
is
highly
inappropriate
for
EPRI
to
offer
information
about
this
subject.
EPRI
can
have
no
information
on
this
subject
that
is
better
than
information
that
comes
directly
from
the
tribes.
Although
EPRI
used
NHANES
and
EPA
data,
it
would
be
far
more
appropriate
to
let
tribes
describe
their
own
consumption
patterns,
as
these
vary
widely
around
the
nation.
EPRI
comments
that
maternal
cord
blood
results
showing
higher
levels
of
Hg
than
originally
protected
have
already
been
accounted
for
by
including
a
single
uncertainly
factor
for
inter
individual
uncertainty
into
the
derived
Reference
Dose.
EPRI's
model
assumed
a
mean
consumption
rate
of
3.7
gram/
day
and
a
maximum
of
200
grams/
day.
Elsewhere,
EPRI
used
EPA's
mean
consumption
estimate
of
14.3
and
a
95th
percentile
rate
of
61.63
grams/
day
(
comparable
to
the
NHANES
numbers
of
14
and
68.75
grams/
day).
The
tribally
specific
data
found
by
GLIFWC
indicate
that
the
actual
numbers
used
should
be
much
higher.

EPRI
also
made
assumptions
for
the
NHANES
data
about
whether
fish
sampled
were
freshwater,
marine,
or
farm­
raised.
The
commenter
prefers
the
use
of
locally
generated
data,
rather
than
NHANES
data;
through
GLIFWC
and
research
conducted
by
MCT
and
by
the
commenter,
the
commenter
has
highly
localized
data
that
gives
real
answers
about
what
tribal
members
eat.
The
commenter
also
prefers
the
use
of
local
data
to
NHANES
data
as
lake
acidity
varies
widely
from
region
to
region
and
the
lakes
in
Minnesota
are
of
an
acidity
that
readily
promotes
methylation
of
Hg.
In
order
to
get
a
truly
accurate
picture,
why
not
use
the
best
data
that
is
available?
EPRI
estimated
freshwater
fraction
versus
marine
fraction
for
Minnesota
is
also
not
indicative
of
what
tribal
members
eat.
The
estimate
of
only
36.55
percent
freshwater
fish
being
eaten
is
far
too
low.
9­
216
Comments
submitted
by
Edison
Electric
Institute
(
EEI)
(
Edison
Electric
Institute,
USEPA
Document
ID
No.
OAR­
2002­
0056­
2929:
June
29,
2004)
state
that
fish
consumption
is
not
a
problem
in
the
U.
S.
because
only
a
small
portion
of
fish
consumed
by
U.
S.
residents
is
affected
by
Hg
deposition.
The
commenter
strongly
disagrees
with
this
statement
provided
by
EEI
and
instead
would
say
a
large
portion
of
the
population
is
consuming
fish
regardless
of
their
actual
Hg
levels.
The
real
question
should
be
what
is
industry
doing
to
ensure
all
our
food­
sources
(
and
not
just
fish)
are
free
of
Hg
and
other
toxins
such
that
they
will
continue
to
have
consumers
in
the
future
for
their
product.

First,
if
we
examine
the
population
numbers,
the
National
Center
for
Health
Statistics
states
that
in
the
U.
S.
alone,
4.03
million
babies
were
born
in
2001.
The
2000
Census
shows
that
there
were
nearly
62
million
women
between
the
ages
of
15
and
44.
The
Center
for
Disease
Control
states
that
in
2003,
70.9
percent
of
new
mothers
nursed
in
the
hospital.
Out
of
4.03
million
babies,
that
means
that
2.86
million
were
breast­
fed
within
their
first
few
days
of
life.
This
totals
up
to
68.89
million
sensitive
humans
being
exposed
to
Hg
on
a
daily
basis.
Breast­
fed
infants
were
counted
twice,
as
they
were
exposed
both
in
utero
and
while
breast­
feeding.
Thus,
23
percent
of
the
total
U.
S.
population
of
297.3
million
is
potentially
at
risk
from
eating
fish.

Second,
local
fish
have
been
tested
and
found
to
contain
Hg.
Advisories
have
been
issued
for
local
fish
consumption,
not
just
by
the
commenter
but
by
44
states
in
the
Union.
Locally
caught
fish
probably
comprise
95
percent
of
all
fish
eaten
by
Band
members.
If
EEI
can
include
such
egregiously
incorrect
statements
as
these,
the
rest
of
its
comments
are
suspect.

EEI
further
states
that
most
Americans,
however,
eat
little
fish.
Half
of
all
U.
S.
citizens
eat
no
fish
whatsoever
and,
of
those
who
do,
the
weekly
average
consumption
is
about
one­
quarter
pound.
Nearly
all
this
fish
is
store­
bought
ocean
fish,
which
is
unlikely
to
much
Hg
emitted
from
U.
S.
sources.
EEI's
comments,
at
least
in
this
subject,
are
totally
erroneous
and
unprofessionally
naive.
Catherine
O'Neill's
article
Mercury,
Risk,
and
Justice
(
34
ELR
11070,
12­
2004)
refutes
this
statement
with
data
from
NHANES
III,
which
asserts
that
roughly
88
percent
of
all
adults
consume
fish
and
shellfish
at
least
once
a
month;
and
1
percent
consume
fish
daily.
This
study
also
shows
that
the
population
who
eats
fish
frequently
differs
greatly
from
the
population
who
eats
fish
less
often.
In
short,
Americans
of
color
consume
fish
far
more
often
than
white
respondents
do,
which
puts
these
groups
at
special
risks.

The
EEI
comments
also
assert
that
since
a
recent
University
of
Rochester
study
has
concluded
that
children
in
the
Seychelles
Islands
appear
to
be
unaffected
by
Hg
exposure,
that
the
utility
industry
should
be
let
off
the
hook.
The
commenter
believes
that
if
the
positions
were
reversed,
EEI
would
also
feel
also
the
results
of
one
study
cannot
totally
refute
the
findings
of
many
other
studies.
Although
the
results
of
the
Seychelle
study
are
surprising
and
show
the
need
for
further
research,
the
whole
of
Hg
study
and
regulation
cannot
be
abandoned
over
it.
In
fact,
the
National
Research
Council
of
the
U.
S.
National
Academy
of
Sciences
has
concluded
that
the
Faroe
Islands
study
is
more
appropriate
for
use
than
the
Seychelles
study
for
deriving
the
Reference
Dose
(
Clean
Air
Task
Force,
Natural
Resources
Defense
Council,
U.
S.
EPA
Document
ID
No.
OAR­
2002­
0056­
3460:
June
29,
2004).
The
commenter
urges
EPA
to
follow
this
advice.
9­
217
The
EEI
supports
the
statement
by
the
American
Medical
Association
that
because
of
the
wide
variations
in
the
concentrations
of
Hg
in
fish
and
shellfish,
it
is
possible
to
have
the
nutritional
benefits
of
moderate
fish
consumption
and
avoid
fish
high
in
Hg
(
cit.
Edison
Electric
Institute,
US
EPA
Document
ID
No.
OAR­
2002­
0056­
2929:
June
29,
2004).
While
this
may
be
true
of
the
typical
consumer,
subsistence
level
people
do
not
have
the
option
of
spending
money
on
store­
bought
fish
or
restaurant
meals.
The
fish
available
to
them
are
native
species
that
come
from
local
waters.

Response:

EPA
appreciates
the
commenter's
input
to
the
record.
Please
see
the
RIA
for
a
detailed
description
of
EPA's
modeling.
Please
also
see
EPA's
discussion
of
hot
spots
in
the
revision
Federal
Register
notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5447)
noted
that
a
significant
reduction
in
Hg
emissions
from
coal­
fueled
power
plants
will
result
in
very
little
change
in
human
exposures
in
the
U.
S.
A
reduction
of
7
percent
would
result
in
a
reduction
in
MeHg
exposure
for
women
of
childbearing
age
by
0.5
to
0.75
percent.
13
While
Peabody
supports
EPA's
goal
of
improving
its
science
related
to
Hg
deposition
and
bio­
accumulation
of
Hg
in
fish,
even
a
significant
improvement
in
EPA's
simplistic
modeling
will
not
change
the
basic
conclusion
that
there
will
be
little
overall
impact
on
either
Hg
deposition
in
the
U.
S.
or
on
Hg
levels
in
fish
if
Hg
emissions
are
decreased
from
U.
S.
coal­
fueled
power
plants.
In
contrast,
as
stated
above,
the
high
cost
of
compliance
with
these
regulations
will
result
in
increased
electrical
costs
to
consumers
and
therefore
increased
mortality.

Response:

EPA
appreciates
the
commenters
input.
Please
see
Chapter
11
of
the
Regulatory
Impact
Analysis
for
a
description
of
the
benefits
of
the
CAMR.

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
referred
to
the
EPA
and
EPRI
comment
that
existing
freshwater
fish
data
collected
by
the
States
may
be
biased
because
it
is
collected
in
areas
of
suspected
contamination
is
misguided.
The
commenter
has
a
fish
sampling
program
that
was
developed
to
protect
public
health
and
has
been
collecting
samples
in
areas
where
the
only
known
Hg
contribution
is
from
atmospheric
deposition.
To
suggest
that
the
National
Study
of
Chemical
Residues
of
Lake
Fish
Tissue
Study
is
superior
for
use
in
a
Hg
benefits
determination
over
data
collected
by
the
State
fish
surveys
is
a
serious
error
in
judgement
by
the
EPA.
The
EPA
must
9­
218
analyze
and
integrate
the
existing
fish
concentration
data
collected
by
the
States
in
any
assessment
of
fish
consumption.
Contrary
to
the
statement
in
the
NODA
that
this
data
will
overestimate
exposure
to
anglers
and
their
families,
the
commenter
believes
this
data
could
be
used
to
get
a
realistic
estimate
of
exposure
to
anglers
and
their
families,
especially
if
the
anglers
are
female
and
of
child­
bearing
age.

The
commenter
is
concerned
about
the
use
of
the
National
Listing
of
Fish
Advisories.
If
this
database
is
to
be
used,
it
is
acknowledged
that
a
bias
toward
overestimation
of
Hg
concentrations
will
occur
on
a
national
scale.
However,
other
information
is
available
within
the
states
for
other
waters
and/
or
species
which
could
reduce
or
eliminate
this
bias.
The
data
would
be
difficult,
at
best,
to
accumulate
within
the
time
frame
necessary
for
consideration
within
this
rule­
making.
A
further
confounding
factor
is
a
lack
of
uniformity
among
the
states
in
the
criterion
used
to
cause
placement
of
a
health
advisory
on
a
fishery
containing
excessive
Hg
concentrations.
For
example,
many
states
use
the
EPA
Hg
criterion
of
0.3
mg/
kg,
whereas
some
states,
including
New
York,
use
the
US
Food
and
Drug
Administration
criterion
of
1.0
mg/
kg
for
the
establishment
of
health
advice
for
Hg
in
fish.
Further,
for
states
with
a
large
number
of
waters
(
such
as
New
York
with
over
7800
lakes,
ponds
and
reservoirs,
over
52,000
miles
of
streams,
and
1.1
million
acres
of
marine
waters),
it
is
physically
and
fiscally
impossible
to
examine
fish
from
all
waters
for
Hg
concentrations.
Therefore,
it
is
a
certainty
that
the
National
Listing
of
Fish
Advisories
will
significantly
underestimate
the
numbers
and
acreage
of
waters
containing
fish
with
Hg
in
excess
of
the
EPA
criterion.
Also,
upon
review
of
EPA's
National
Listing
of
Fish
Advisories
web­
page,
the
commenter
found
the
data
presented
for
individual
fish
from
New
York
waters
are
for
the
years
1990­
1997
only,
thus,
it
is
somewhat
dated,
limited
and
incomplete.
The
listing
of
health
advisories
is
current
through
2003,
but
of
little
value
for
EPA's
purposes
(
i.
e.,
to
estimate
MeHg
concentrations
in
fish
and
consumption
rates
of
such
fish)
because
actual
Hg
concentrations
are
not
given
and
only
species
with
Hg
concentrations
above
the
advisory
criterion
are
listed.

The
National
Study
of
Chemical
Residues
in
Lake
Fish
Tissue
was
designed
to
provide
a
statistical
representation
(
with
stratified
random
sampling
by
size
of
lakes)
of
the
relative
distribution
of
Hg
in
fish
throughout
the
US,
although
it
excludes
the
Great
Lakes.
The
study
was
designed
to
select
one
composite
of
a
bottom
dwelling
fish
species
and
one
composite
of
a
predator
fish
species.
Recommended
bottom
dwelling
species
included
brown
bullhead
or
similar
catfish
species,
carp,
or
white
sucker.
All
these
bottom
dwelling
species
are
not
good
accumulators
of
Hg
since
they
represent
lower
trophic
levels,
typically
are
not
predatory,
and
often
do
not
show
substantial
accumulations
of
Hg
even
when
concentrations
may
be
elevated
in
other
species.
The
predatory
species
recommended
in
the
project
design
include
largemouth
and
smallmouth
bass
and
walleye,
among
others,
which
represent
top
level
predator
species
that
are
good
indicators
of
Hg
concentrations
within
a
waterbody,
provided
they
are
present
within
the
water.
Not
all
waters
sampled
will
contain
one
or
more
of
these
predator
species.
Other
predator
species
included
in
the
study
(
several
species
of
trout
plus
northern
pike
and
black
or
white
crappie)
provide
indications
of
Hg
concentrations
that
are
intermediate
between
the
bottom
dwelling
fish
and
the
top
predators.
9­
219
Use
of
the
National
Study
of
Chemical
Residues
in
Lake
Fish
Tissue
results
could
present
bias
based
on
how
the
data
is
presented.
First,
the
five
Great
Lakes
are
excluded,
and
each
of
the
Great
Lakes
are
known
to
contain
species
of
fish
which
exceed
the
EPA
Hg
criterion
of
0.3
mg/
kg,
therefore,
millions
of
acres
of
water
may
be
excluded
from
consideration,
i.
e.,
2.65
million
acres
in
New
York
alone.
Second,
the
relative
proportion
of
lakes
adversely
affected
by
Hg
could
be
characterized
as
either
numbers
of
waters
or
surface
acreage.
Characterization
by
both
methods
should
be
incorporated
into
an
evaluation
to
give
a
more
accurate
description
of
impact
and
potential
benefits
to
be
derived.
Other
concerns
that
the
commenter
has
about
the
utility
of
this
study
as
it
relates
to
EPA's
goals
include:
1)
measurements
of
variability
in
the
data
will
be
limited
because
samples
are
composites
(
i.
e.,
only
one
data
record
for
each
species
per
lake);
2)
sample
composites
limit
assessments
to
one
size
class
of
fish
per
lake,
restricting
the
chance
to
examine
fish
size­
Hg
concentration
relationships;
3)
this
study
will
only
provide
a
very
generic
regional
assessment
of
fish
Hg
concentrations
because
less
than
0.5
percent
(
n=
25)
of
the
lakes
in
the
state
were
sampled
and
the
distribution
of
those
lakes
selected
do
not
reflect
the
distribution
of
lakes
within
the
state
(
lakes
in
the
Adirondacks,
a
six
million
acre
area
known
to
have
Hg
issues,
represent
over
60
percent
of
lakes
in
New
York
while
only
36
percent
of
the
national
study
lakes
in
New
York
were
from
the
Adirondacks);
4)
the
analysis
of
only
two
species
per
lake
is
restrictive
and
the
data
are
further
diluted
because
species
selection
varied
by
lake;
and
5)
overall
this
was
a
screening­
level
study
with
limited
application
for
determining
important
regional
and
size/
species­
related
Hg
concentration
patterns
in
a
variety
of
popular
and
edible
fish
species.

The
commenter
is
concerned
with
some
of
the
potential
assumptions
that
can
be
used
to
determine
human
exposure
and
requests
that
the
EPA
adhere
to
the
maximum
individual
risk
(
MIR)
concept
as
discussed
in
the
Residual
Risk
Report
to
Congress.
In
the
case
of
MeHg
exposure,
the
MIR
represents
the
highest
estimated
risk
to
an
exposed
individual
based
on
realistic
high­
end
consumption
and
fish
Hg
concentration
inputs.
The
use
of
the
average
Hg
concentration
for
the
average
fish
combined
with
the
average
fish
consumption
rate
will
result
in
an
average
benefit
determination
that
will
underestimate
the
benefits
of
reducing
Hg
emissions.
The
EPA
exposure
handbook
has
fish
consumption
rate
for
the
95th
percentile
at
25
grams
per
day
for
non­
subsistence
people
and
170
grams
per
day
for
subsistence
fish
eaters.
The
EPA
Methyl
Mercury
Water
Quality
Criterion
uses
freshwater
fish
consumption
rates
of
156.3
grams/
day
for
children,
165.5
grams
/
day
for
women
of
child­
bearing
age
and
17.5
grams/
day
for
adults
in
the
general
population.
The
benefits
analysis
should
reflect
the
MIR
concept
and
use
the
high­
end
consumption
parameters
for
fish
consumption
for
women
of
childbearing
age
and
children
to
insure
a
proper
accounting
of
the
benefits
of
reducing
Hg
emissions
for
this
sector
of
the
population.

Response:

Please
see
Chapter
5
of
the
RIA
for
a
discussion
of
concentrations
of
mercury
in
fish.
Please
also
see
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112
Notice
and
in
the
9­
220
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
presented
below,
several
specific
issues
that
would
benefit
from
such
careful
peer
review.
The
commenter
did
not
intend
this
list
to
be
comprehensive,
but
merely
included
it
to
illustrate
that
the
agency
must
address
critical
scientific
issues
prior
to
making
changes
to
its
deposition
and
watershed
models
or
conducting
other
components
of
the
proposed
analyses.
This
overview
serves
to
demonstrate
that
it
would
be
foolish
to
hold
up
final
Hg
regulations
while
EPA
further
investigates
certain
technical
issues
concerning
the
emissions,
fate,
and
toxicity
of
Hg
from
power
plants.

Hg
deposition
and
estuarine
and
marine
species.
Although
EPRI
has
conducted
an
assessment
of
the
impact
of
Hg
deposition
on
marine
and
estuarine
fish
species,
this
is
a
particular
area
where
EPA
needs
to
consult
the
broader
scientific
community.

The
commenter
urged
the
agency
to
give
additional
weight
to
the
findings
of
the
METAALICUS
project
as
the
researchers
on
this
team
are
internationally
recognized
Hg
experts
conducting
unbiased
scientific
research.
The
commenter
noted
that
EPA
was
quick
to
emphasize
that
results
from
METAALICUS
were
ongoing
and
still
being
refined
while
offering
no
such
caution
when
describing
PERI's
conclusions
on
numerous
scientific
issues
(
e.
g.,
plume
transformation,
global
inventories,
global
transport
of
Hg,
marine
impacts,
human
exposure,
etc.)

The
Mercury
Report
to
Congress
contains
a
large
amount
of
data
on
high­
end
fish
consumers.
EPA
should
augment
this
information
with
more
recent
regional
studies
on
fish
consumption
patterns
such
as
have
been
conducted
in
New
England.

The
commenter
continued
to
take
issue
with
the
current
EPA
definition
of
hot
spots
which
is
limited
to
levels
of
Hg
in
fish
tissue
that
would
cause
the
human
population
to
exceed
the
RfD.
Given
the
human
and
ecological
health
risks
associated
with
Hg
exposure,
the
definition
of
hot
spots
should
be
recast
to
include
local,
regional
and
national
hot
spots
as
identified
by
(
1)
hot
spots
in
deposition,
(
2)
hot
spots
in
water,
and
(
3)
hot
spots
in
biota.

New
research
regarding
the
extent
of
Hg
in
water,
fish
and
wildlife
and
the
occurrence
of
hot
spots
in
the
Northeast
U.
S.
is
forthcoming
in
the
journal
Ecotoxicology.
EPA
should
incorporate
these
findings
is
any
new
assessments
of
the
impacts
of
Hg
emissions.

The
commenter
stated
that
despite
the
scientific
uncertainties
of
the
broad
assessment
that
EPA
has
described,
the
agency
can
still
improve
the
benefits
assessment
in
the
short
term
for
the
purpose
of
preparing
a
Regulatory
Impacts
Analysis
for
the
final
rule.
Specifically,
an
assessment
and
monetization
of
cardiovascular
effects
in
children
and
adults
and
the
loss
of
IQ
points
in
children
can
be
accomplished
with
the
data
at
hand
concerning
Hg
blood
levels
in
the
U.
S.
9­
221
Response:

Please
see
Chapter
3
of
the
CAMR
Regulatory
Impact
Analysis
for
a
detailed
discussion
of
mercury
in
the
environment,
including
an
assessment
of
the
response
time
for
systems
after
a
change
in
mercury
deposition.
Please
also
see
Section
8
for
a
discussion
of
the
change
in
mercury
deposition
based
on
air
quality
modeling
and
Chapters
11
for
a
benefits
analysis
of
the
CAMR.
Please
also
see
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112
Notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

The
commenter
(
OAR­
2002­
0056­
5465)
stated
that
additionally,
they
would
like
to
address
Part
II
of
the
NODA,
"
Step
4
of
EPA's
Revised
Benefits
Methodology:
Fish
Consumption
and
Human
Exposure."
Again,
note
that
by
focusing
its
comments,
the
commenter
does
not
mean
to
suggest
that
this
is
the
only
step
in
EPA's
proposed
method
that
warrants
critique.

As
EPA
noted,
consumption
of
fish
was
the
primary
pathway
for
human
exposure
to
MeHg.
As
such,
two
sets
of
factors
became
important
to
determining
human
exposure:
those
describing
the
concentration
of
MeHg
in
fish
tissue
and
those
describing
fish
consumption
practices
for
humans.

Methylmercury
Concentration
In
the
NODA,
EPA
indicated
that
it
is
considering
looking
to
the
National
Study
of
Chemical
Residues
in
Lake
Fish
Tissue
(
also
referred
to
as
the
National
Fish
Tissue
Study
(
NFTS)),
given
its
concern
that
data
from
the
EPA's
National
Listing
of
Fish
Advisories
(
NLFA),
which
is
collected
by
state
agencies,
may
be
"
biased."
Specifically,
EPA
argued
that
the
fact
that
states
generally
collect
fish
tissue
Hg
data
from
(
a)
"
areas
of
increased
angling
activity,"
and
(
b)
"
areas
of
suspected
contamination"
means
that
this
data
may
"
overestimate
exposure
to
anglers
and
their
families."
This
concern
is
largely
misplaced.
First,
from
a
public
health
perspective,
it
is
entirely
appropriate
to
sample
from
areas
likely
to
be
fished,
i.
e.,
"
areas
of
increased
angling
activity,"
in
order
to
determine
the
MeHg
concentration
in
species
likely
to
be
consumed
by
humans.
To
prefer
a
random
sampling
method
(
as
undertaken
in
the
NFTS)
is
to
misfocus
the
relevant
inquiry.
If
the
waterbodies
sampled
are
not
fished
by
humans,
then
humans
are
not
going
to
be
exposed
via
fish
in
those
waterbodies.
The
effect,
of
course,
is
to
dilute
the
relevant
value
for
mean
MeHg
concentration
in
fish
tissue,
resulting
in
an
estimate
of
exposure
that
is
inaccurate
and
thus
scientifically
unsound.
On
a
related
note,
it
makes
sense
to
consider,
additionally,
the
concentration
in
the
tissue
of
fish
caught
in
areas
once
favored
by
humans
but
no
longer
fished
9­
222
due
to
advisories
warning
of
contamination.
Because
humans
would
fish
in
these
areas
but
for
unaddressed
contamination,
it
is
reasonable
to
set
environmental
standards
at
levels
protective
of
consumption
here.
Second,
although
some
states
and
tribes
initially
began
their
data
collection
efforts
with
waterbodies
that
they
believed
to
be
contaminated,
it
should
be
kept
in
mind
that
many
states
and
tribes
have
been
gathering
this
data
for
some
time,
and
have
now
sampled
broadly
and
extensively
from
the
waterbodies
within
their
respective
jurisdictions.
In
fact,
the
commenter
urged
the
EPA
to
consult
with
the
Great
Lakes
Indian
Fish
and
Wildlife
Commission
(
GLIFWC)
about
data
they
have
gathered
that
documents
MeHg
concentration
in
the
tissue
of
locally
consumed
species
at
levels
greater
than
suggested
by
state
or
federal
data.

Fish
Consumption
Rates
and
Practices
EPA
stated
in
the
NODA
that
it
is
seeking
information
on
fish
consumption
rates
by
different
affected
populations,
particularly
in
the
eastern
half
of
the
U.
S.
The
commenter
referred
EPA
to
the
analysis
of
various
groups'
fish
consumption
practices
conducted
by
Professor
O'Neill
(
in
the
attached
article,
see
OAR­
2002­
0056­
5465)
and
to
the
fish
consumption
rates
for
the
various
Ojibwe
and
other
Great
Lakes
tribes
cited
therein.
The
commenter
also
referred
EPA
to
the
discussion
and
studies
in
the
report
of
the
National
Environmental
Justice
Advisory
Committee,
Fish
Consumption
and
Environmental
Justice.

EPA
asked
specifically
whether
the
fish
consumption
rates
used
in
the
Water
Quality
Criterionx
or
produced
in
the
Peterson,
et
al.,
study
are
appropriate
for
assessing
the
effects
on,
inter
alia,
tribal
populations.
In
the
first
place,
the
commenter
emphasized
that
the
only
ones
with
the
knowledge
to
respond
to
this
question
are
the
affected
tribes
themselves.
Thus,
if
EPA
is
to
produce
an
accurate
and
defensible
assessment,
it
must
pose
this
question
directly
to
the
various
tribes.
Moreover,
EPA
should
honor
its
commitment
to
consult
with
tribes
on
a
government­
to­
government
basis
on
issues,
such
as
this,
that
affect
tribal
rights
and
resources.

Although
the
commenter
deferred
to
tribes'
individual
responses
to
the
above
question,
it
nevertheless
noted
that
the
fish
consumption
rates
used
by
the
Water
Quality
Criterion
(
produced
by
the
national
CSFII
study)
and
produced
by
the
local
Peterson,
et.
al.,
study
are
markedly
lower
 
more
than
an
order
of
magnitude
lower
­
than
the
fish
consumption
rate
produced
by
a
1993
GLIFWC
survey
of
tribal
spearers
(
189.6
to
393.8
grams/
day
in
the
spring)
and
the
fish
consumption
rate
adopted
by
the
Leech
Lake
Band,
one
of
the
Minnesota
Chippewa
Tribe
members
(
227
grams/
day).
These
differences
and
their
implications
are
elaborated
in
the
attached
article
by
Professor
O'Neill.
Further
(
see
OAR­
2002­
0056­
5465)
,
a
host
of
other
aspects
of
tribal
members'
different
fish
consumption
practices
(
e.
g.,
"
acute"
consumption
in
accordance
with
seasonal
or
cultural
practices;
different
average
meal
size;
different
species
consumed)
are
relevant
to
an
assessment
of
exposure
and
must
be
considered
by
EPA.
Several
of
these
aspects
are
discussed
in
the
attached
article
by
Professor
O'Neill
(
see
e­
docket
OAR­
2002­
0056­
5465);
in
addition,
CPR
refers
EPA
to
discussions
by
tribal
commenters
such
as
the
Fond
du
Lac
Tribe.
xii
As
a
general
matter,
in
assessing
the
effects
on
tribal
populations,
EPA
should
eschew
data
from
studies
that
are
national
in
focus
(
such
as
the
CFSII
study)
and/
or
are
non­
tribally
conducted
(
such
as
the
Peterson,
et
al.,
study),
in
favor
of
studies
of
the
relevant
tribal
population
conducted
9­
223
by
the
tribe/
the
relevant
intertribal
association
(
or
at
least
suggested
by
the
tribe
in
consultation).
Such
a
preference
would
produce
more
accurate
and
therefore
scientifically
defensible
results.
In
this
vein,
the
commenter
found
EPRI's
suggested
fish
consumption
rates
particularly
ill
conceived.
PERI
purports
to
construct
"
local"
fish
consumption
rates,
but
does
so
by
weaving
together
a
host
of
assumptions
that
simply
do
not
comport
with
actual
local
practice,
that
serve
chiefly
to
underestimate
exposure
(
e.
g.,
PERI
assumes
a
fish
MeHg
concentration
of
0.12
mg/
kg
MeHg),
and
that
work
backward
from
NHANES
data
on
blood
Hg
levels
to
fabricate
likely
consumption
rates
for
each
state
­
a
highly
questionable
method
in
the
face
of
numerous
empirical
studies
documenting
actual
local
consumption
rates.

Finally,
the
commenter
noted
that
EPA
needed
to
account
for
the
fact
that
the
tribal
consumption
rates
described
in
the
Peterson,
et
al.,
study
may
reflect
current
consumption
levels
that
are
artificially
low.
As
the
Peterson
study
itself
notes,
some
tribal
members
may
have
already
altered
their
fishing
and
fish
consumption
practices
to
some
degree
in
view
of
the
fish
consumption
advisories
issued
by
the
states
and
the
tribes.
To
the
extent
this
is
the
case,
the
fish
consumption
rate
that
is
generated
by
a
survey
such
as
that
conducted
by
Peterson
does
not
reflect
what
tribal
members
would
consume,
were
the
fish
not
contaminated
with
Hg.
Patrick
West,
et
al.,
termed
this
the
"
suppression
effect:"
that
is,
the
fish
consumption
rate
revealed
by
surveys
in
these
instances
reflects
a
"
suppressed"
rate
of
consumption.
This
point
applies
with
particular
force
to
tribes,
who
have
treaty
guarantees
to
a
certain
level
of
consumption.
Even
if
tribal
members
have
had
to
forego
fish
recently
because
fish
have
been
allowed
to
become
contaminated,
they
are
entitled
not
to
do
so;
thus
environmental
standards
should
be
set
to
protect
consumption
at
the
higher,
treaty­
guaranteed
level
of
consumption,
not
the
lower,
suppressed
level
of
consumption.
Again,
tribes
will
be
uniquely
positioned
to
be
able
to
identify
and
account
for
suppression
effects
for
their
populations;
as
such,
tribally
conducted
studies
or
tribally
interpreted
data
are
to
be
preferred.

Response:

EPA
agrees
that
for
some
situations
(
e.
g.,
commenter
examples)
the
value
142.4
may
be
an
underestimate
of
fish
consumption.
This
is
the
value
that
the
Agency
recommends
in
its
water
quality
standards
program
to
States
with
high­
consuming
sub­
populations,
in
lieu
of
site­
specific
data
when
those
states
are
faced
with
developing
a
water
quality
standard
for
methylmercury
that
is
protective
of
the
fish
consumption
use
of
state
waters
demonstrated
by
those
subpopulations
Where
a
state
has
local
information
indicating
higher
rates
of
fish
consumption
than
142.4,
it
is
recommended
that
they
use
it.
In
the
benefits
analyses
performed
for
this
rule,
several
consumption
scenarios
were
considered
based
on
the
available
data
pertinent
to
the
population
modeled
(
recreational
anglers),
but
the
value
of
142.4
g/
day
was
not
used.

The
EPA
has
included
four
potentially
high­
risk
populations
in
the
RIA,
including:
(
a)
high­
end
recreational
fisher
anglers
(
with
consumption
rates
at
or
above
the
95th
percentile
for
this
group),
(
b)
economically
disadvantaged
high­
end
consumers
with
poverty­
status
income
and
fish
consumption
rates
at
or
above
the
95th
percentile
for
freshwater
anglers,
(
c)
Hmong
in
Minnesota
and
Wisconsin
and
(
d)
Chippewa
in
Minnesota,
Wisconsin
and
Michigan.
These
9­
224
special
population
are
intended
to
provide
coverage
for
groups
of
individuals
who
through
choice,
necessity
or
socio­
cultural
practices
consume
relatively
high
levels
of
self­
caught
freshwater
fish.
Inclusion
of
these
four
special
populations
is
also
intended
to
support
consideration
of
distributional
equity
in
relation
to
EGU­
based
environmental
regulation
(
i.
e.,
would
a
subset
of
the
US
population
benefit
disproportionately
from
regulations
to
reduce
mercury
emissions
from
EGUs)?

Fish
consumption
rates
for
all
four
special
populations
have
been
developed
based
on
peer­
reviewed
survey
data
that
are
representative
of
the
particular
group
of
interest.
In
the
case
of
the
Chippewas,
EPA
has
used
a
mean
value
obtained
from
the
literature
(
see
RIA
Chapter
10
for
additional
details).
However,
it
was
not
possible
to
identify
a
high­
end
percentile
consumption
rate
based
on
peer­
reviewed
literature
and
consequently,
the
mean
consumption
rate
was
used
in
the
benefits
analysis
without
consideration
for
variability
in
fish
consumption
rates
across
individuals.
However,
in
response
to
information
provided
in
NODA
comments
(
including
that
provided
by
this
commentor),
EPA
has
conducted
a
sensitivity
analysis
for
highend
fish
consumption
by
the
Chippewa
population
using
(
a)
the
maximum
delta
fish
tissue
concentration
(
for
Walleye)
modeled
in
states
where
Chippewa
are
located
for
the
RIA
for
Option
1
and
Option
2
(
i.
e.,
the
maximum
change
in
MeHg
fish
tissue
concentrations
modeled
in
Michigan,
Wisconsin
or
Minnesota
under
CAMR
Options
1
and
2)
and
(
b)
the
maximum
seasonal
fish
consumption
rate
provided
in
the
NODA
comments
(
i.
e.,
393.8
g/
day).
The
results
suggest
that
total
IQ
reductions
under
Option
1
and
2,
even
under
these
conservative
assumptions
(
i.
e.,
highest
change
in
mercury
fish
tissue
concentrations
under
Option
1
and
Option
2
and
the
highest
seasonal
fish
consumption
rate),
are
relatively
low
at
0.32
IQ
points
per
child.
This
relatively
low
IQ
benefit
for
this
conservative
scenario
reflects
the
fact
that,
while
states
where
the
Chippewa
are
located
may
have
relatively
high
absolute
(
total)
MeHg
concentrations
in
target
fish
species,
modeled
EGU
deposition
over
these
areas
is
relatively
low
and
consequently,
CAMR
is
likely
to
produce
relatively
small
changes
in
mercury
fish
tissue
concentrations
compared
with
other
areas
where
EGU
deposition
is
higher
(
e.
g.,
the
Ohio
river
valley).
These
findings
argue
against
a
distributional
equity
concern
for
the
Chippewa
in
this
portion
of
the
study
area
(
although
this
conclusion
needs
to
be
considered
in
the
context
of
the
overall
precision
and
specificity
of
the
benefits
model
used
in
this
RIA
which
is
not
intended
for
site­
specific
analysis
and
was
developed
for
application
at
the
regional­
level).

EPA
acknowledges
that
states
contributing
data
to
the
NLFA
may
use
different
protocols
that
result
in
mercury
fish
tissue
concentrations
having
different
degrees
of
bias
(
e.
g.,
focus
on
most
impacted
waterbodies
versus
waterbodies
most
heavily
fished).
The
degree
of
uncertainty
and
potential
relevance
in
adversely
impacting
the
RIA
will
depend
on
the
specific
protocol
being
considered.
If
a
state
focuses
fish
sampling
on
areas
experiencing
heavy
fishing
activity,
then
this
will
actually
benefit
the
economic
analysis
by
contributing
fish
tissue
measurements
from
waterbodies
experiencing
fishing
activity.
Conversely,
states
that
focus
on
areas
believed
to
have
a
mercury
contamination
problem,
could
bias
the
NLFA
dataset
in
a
conservative
direction
if
those
waterbodies
are
not
fished
relative
to
other
less­
impacted
waterbodies.
Given
potential
concerns
over
the
NLFA
and
potential
bias
resulting
from
the
individual
state's
sampling
protocols,
EPA
completed
a
statistical
comparison
of
the
NLFA
and
the
NFTS
datasets
(
the
9­
225
NFTS
uses
a
rigorous
statistical
sampling
procedure
to
provide
unbiased
coverage
for
waterbodies).
This
statistical
comparison
showed
that
the
NLFA
and
NFTS
datasets
were
indistinguishable
statistically
except
at
the
extreme
high
end,
where
there
was
some
conservative
bias
identified
in
the
NFTS.
These
findings
support
the
use
of
the
NLFA
(
along
with
the
NFTS)
in
conducting
national
or
regional
benefits
analyses,
since
these
analyses
focus
on
generalized
trends
in
mercury
fish
contamination.
However,
EPA
acknowedges
that
assessments
of
extreme
high­
end
exposure
and
risk
could
be
biased
somewhat
high
if
the
NLFA
data
are
used.
However,
it
is
important
to
reiterate
that,
if
the
NLFA
bias
reflects
waterbodies
where
fishing
activity
is
likely,
then
this
identified
high­
end
bias
may
not
be
problematic
and
indeed,
could
be
preferred
(
i.
e.,
it
would
not
represent
true
bias).

Although
EPA
considers
inclusion
of
the
NFTS
data
extremely
valuable
in
providing
additional
coverage
for
the
study
area,
it
is
important
to
note
that
the
majority
of
measured
fish
tissue
concentrations
were
contributed
by
the
NLFA
and
not
by
the
NFTS.
This
fact
partially
addresses
the
commentor's
concerns
(
i.
e.,
the
benefits
analysis
primarily
reflects
NLFA
data
with
a
smaller
relative
contribution
from
the
NFTS
dataset).
However,
several
points
can
be
made
in
response
to
concerns
raised
by
the
commentor
regarding
the
NFTS
data.
Although
NFTS
composites
do
reduce
variability
(
primarily
related
to
fish
size),
because
size
information
is
available
for
many
of
the
entries
in
NLFA,
standardization
using
the
NDMMFT
model
did
have
access
to
variability
data
related
to
size
through
the
NLFA.
The
Great
Lakes
are
not
being
included
in
the
primary
benefits
analysis
because
of
greater
uncertainty
in
linking
mercury
deposition
changes
from
power
plants
to
fish
tissue
concentrations
relative
to
lakes
and
rivers.
The
relatively
small
NFTS
dataset
is
offset
to
some
extent
by
inclusion
of
the
larger
NLFA
dataset,
although
concerns
of
fish
tissue
sampling
coverage
(
both
spatially
and
temporally)
do
persist.
For
additional
information
on
fish
tissue
datasets
used
in
the
benefits
analysis,
see
Sections
10
and
14.

Comment:

One
commenter
(
OAR­
2002­
0056­
5455),
in
reference
to
fish
consumption
and
human
exposure,
responded
specifically
to
Step
4
of
EPA's
Proposed
Revised
Benefits
Methodology:
Fish
Consumption
and
Human
Exposure.
The
commenter
believed
that
EPA's
assumed
consumption
level
of
142.4
grams/
day
underestimates
actual
levels
consumed
by
the
commenters.
A
survey
by
the
Great
Lakes
Indian
Fish
and
Wildlife
Commission
(
GLIFWC)
indicated
that
members
of
Ojibwe
Great
Lakes
tribes
consumed
anywhere
from
155.8­
240.7
grams/
day
in
conjunction
with
fall
spearing.
The
spring
spearing
season
can
lead
to
consumption
rates
anywhere
from
189.6­
393.8
g/
day.
The
Leech
Lake
Band,
one
of
the
Minnesota
Chippewa
Tribe
member
bands,
has
determined
that
a
fish
consumption
rate
of
227
g/
day
is
possible
under
its
treaty­
protected
fish
harvesting
right.
The
GLIFWC
study
also
showed
that
95
percent
tribal
respondents
consumed
at
least
one
meal
per
week
of
the
walleye
caught
during
spearing
and
over
12
percent
ate
more
than
7
meals
per
week.
This
consumption
is
very
seasonal
in
nature,
with
consumption
rates
varying
by
as
much
as
150
g/
day
between
the
fall
and
the
spring.
The
survey
also
reveals
that
the
average
meal
size
may
differ
widely
among
groups.
EPA
assumes
an
"
average"
meal
size
of
6
ounces,
or
about
170
grams.
However,
GLIFWC
finds
that
tribal
fishers
9­
226
tend
to
eat
an
"
average"
meal
ranging
from
13­
27
ounces,
about
369­
766
grams.
EPA
should
adjust
their
analysis
accordingly.

Mercury
levels
in
fish
caught
and
eaten
locally
may
exceed
levels
found
in
commercially
available
fish
or
shellfish.
U.
S.
Health
and
Human
Services
and
EPA
data
show
that
commercially
important
fish
like
tuna,
shrimp,
salmon,
and
catfish
can
range
in
MeHg
concentrations
from
0.01­
0.35
parts
per
million
(
ppm).
But
recent
EPA
data
for
freshwater
fish
show
that
MeHg
concentrations
for
important
species
like
walleye,
bass,
trout,
pike,
and
perch
can
vary
from
0.25­
1.03
ppm.
This
study
further
shows
that,
in
a
representative
sampling
of
fish
from
U.
S.
lakes,
80
percent
of
predator
fish
levels
exceeded
EPA's
safe
limit
of
0.13
ppm
for
women.
Fifty­
five
percent
of
all
freshwater
fish
(
predatory
and
non­
predatory)
sampled
exceeded
this
level
and
76
percent
of
all
fish
sampled
exceeded
EPA's
safe
limit
for
children
under
three.
By
contrast,
the
commenter
used
a
0.05
ppm
trigger
level
for
a
"
1
meal/
week"
consumption
advisory
for
sensitive
populations.

In
all
instances,
the
numbers
given
above
exceed
EPA's
assumed
levels
of
consumption
and
Hg
content,
sometimes
by
large
amounts.
In
further
support
of
our
viewpoint,
EPA's
document
Fish
Consumption
and
Environmental
Justice:
A
Report
Developed
from
the
National
Environmental
Justice
Advisory
Committee
Meeting
of
December
3­
6,
2001
(
2002
revised),
states
that
although
EPA's
numbers
are
an
improvement
over
previous
figures,
they
do
not
address
consumption
at
the
highest
potential
rates.
Please
take
this
new
information
into
account
when
reviewing
your
data
about
human
exposure.

EPA
made
no
attempt
to
address
cumulative
effects
of
toxic
exposures
in
people
who
consume
large
quantities
of
other
natural
resources
(
i.
e.,
venison,
moose,
bear,
waterfowl,
wild
rice,
blueberries),
although
this
would
be
a
scientifically
sound
idea
if
EPA
truly
wants
to
protect
sensitive
members
of
the
population.
An
analysis
of
local
fish
tissue
samples
typical
of
those
consumed
by
the
commenters
were
analyzed
and
Reservation
consumption
advisories
set
accordingly.
Sensitive
populations
are
advised
to
eat
no
more
than
one
meal
per
month
of
most
fish
species,
even
if
care
is
taken
to
eat
only
the
smaller
fish
of
the
species.
For
those
fishing
for
subsistence
or
cultural
practice,
this
is
a
ridiculously
small
amount
of
fish.
It
is
likely
that
most
commenters
were
eating
amounts
in
excess
of
this
recommendation.
Also,
because
the
fish
are
harvested
with
nets,
it
is
impossible
to
target
"
safe"
sizes.
This
issue
was
also
not
addressed
in
EPA's
analysis.

As
alluded
to
in
the
previous
paragraph,
EPA
has
addressed
Hg
in
fish
tissue
but
has
done
nothing
to
address
Hg
in
other
food
sources
such
as
wild
rice,
moose,
and
waterfowl.
The
commenter
had
found
that
Hg
levels
in
some
wild
ducks
occur
at
the
same
levels
as
in
fish
tissue.
Although
these
results
are
from
only
a
limited
number
of
ducks
and
follow­
up
studies
are
needed,
this
is
disturbing
information
that
EPA
may
not
be
aware
of.
Because
moose,
ducks,
and
other
animals
eat
primarily
water
plants,
they
are
vulnerable
to
the
effects
of
Hg
poisoning.

It
should
not
be
utility's
role
to
tell
the
public
(
via
the
IPM
model)
at
what
level
standards
should
be
set
so
they
can
deliver
electricity
to
us
while
fulfilling
regulations
at
the
least
cost
to
9­
227
themselves.
It
is
up
to
EPA
to
determine
how
much
Hg
can
be
allowed
in
the
environment
and
for
utilities
to
use
their
business
acumen
to
determine
how
they
can
best
meet
the
standards
EPA
has
set.
Likewise,
EPA
should
not
tell
tribes
how
many
and
what
type
of
fish
they
can
consume.
Instead,
the
tribes
should
be
able
to
tell
EPA
what
their
consumption
levels
are
and
EPA
should
make
the
fish
safe
for
them
to
consume
at
those
levels.
If
this
precedence
is
set,
soon
EPA
will
be
calling
upon
us
to
limit
the
amount
of
air
we
can
breathe
and
water
we
can
drink.
Limiting
consumption
of
an
otherwise
healthy
food
source
is
not
the
answer.

Studies
showed
that
even
when
people
were
aware
of
the
dangers
of
eating
fish
from
local
waters,
they
often
ignored
the
warnings.
Likewise,
the
commenter
believed
that
many
tribal
people
are
unlikely
to
give
up
a
subsistence­
based,
culturally
rich
tradition
even
though
warnings
have
been
issued.
Some
of
these
people
will
either
continue
to
fish
or
go
hungry.
Since
Hg
can
be
neither
tasted
nor
smelled
in
fish
meat,
this
may
embolden
some
consumers
to
eat
more
than
is
safe.
Furthermore,
most
people
are
unaware
of
recent
findings
indicating
that
consumption
of
Hg­
contaminated
fish
can
lead
to
heart
disease.
Both
men
and
those
women
not
of
childbearing
age
may
be
over
consuming
based
on
their
ignorance
of
this
information.

Comments
submitted
by
PERI
addressing
fish
consumption
rates
of
tribal
people
are
not
accurate.
Since
PERI
favors
less
stringent
control
options
than
the
tribes
do,
it
is
highly
inappropriate
for
PERI
to
offer
information
about
this
subject.
PERI
can
have
no
information
on
this
topic
that
is
better
than
information
that
comes
directly
from
the
tribes.
Although
PERI
used
NHANES
and
EPA
data,
it
would
be
far
more
appropriate
to
let
tribes
describe
their
own
consumption
patterns,
as
these
vary
widely
around
the
nation.
PERI
comments
that
maternal
cord
blood
results
showing
higher
levels
of
Hg
than
originally
thought
have
already
been
accounted
for
"
by
including
a
single
uncertainly
factor
for
inter­
individual
uncertainty
into
the
derived
Reference
Dose."
The
commenter
wonders
why
Reference
Doses
got
only
one
factor
of
uncertainty
while
the
MACT
standard
calculated
by
EPA
contains
several
factors
to
correct
for
variability
in
MACT
floor
calculations,
compliance
methods,
fuel
types,
etc..
EPRI's
model
assumed
a
mean
consumption
rate
of
3.7
g/
day
and
a
maximum
of
200
g/
day.
Elsewhere,
PERI
used
EPA's
mean
consumption
estimate
of
14.3
and
a
95th
percentile
rate
of
61.63
g/
day
(
comparable
to
the
NHANES
numbers
of
14
and
68.75
g/
day).
The
tribally
specific
data
given
earlier
in
this
letter
indicated
that
the
actual
numbers
used
should
be
much
higher
to
account
for
seasonal
variation.
While
the
commenter
assumed
a
daily
consumption
rate
of
60
g/
day
in
setting
its
water
quality
standards,
this
rate
of
consumption
is
believed
to
be
far
more
common
than
what
would
occur
at
the
95th
percentile."

PERI
also
made
assumptions
for
the
NHANES
data
about
whether
fish
sampled
were
freshwater,
marine,
or
farm­
raised.
Again,
the
commenter
preferred
the
use
of
locally­
generated
data,
rather
than
NHANES
data,
because
such
localized
data
gives
real
answers
about
what
tribal
members
eat,
which
are
better
than
projections
from
non­
tribal
people.
In
addition,
local
data
helps
capture
lake
acidity
variability
that
occurs
from
region
to
region.
As
lakes
in
northern
Minnesota
are
of
an
acidity
that
readily
promotes
methylation
of
Hg,
the
commenter
believed
it
is
essential
that
local
data
be
used
as
much
as
possible.
In
order
to
get
a
truly
accurate
picture,
why
not
use
the
best
data
that
is
available?
EPRI's
estimated
"
freshwater
fraction
versus
marine
9­
228
fraction"
for
Minnesota
is
also
not
indicative
of
what
tribal
members
eat.
The
estimate
of
only
36.55
percent
freshwater
fish
(
of
total
fish
consumed)
is
far
too
low.

Comments
submitted
by
Edison
Electric
Institute
(
EEI)
stated
that
fish
consumption
is
not
a
problem
in
the
U.
S.
because
only
a
small
portion
of
fish
consumed
by
U.
S.
residents
is
affected
by
Hg
deposition.
A
large
portion
of
the
population
is
consuming
fish,
and
those
fish
are
contaminated
with
Hg.
First,
let's
look
at
population
numbers.
The
National
Center
for
Health
Statistics
states
that,
in
the
U.
S.,
4.03
million
babies
were
born
in
2001.
The
2000
Census
shows
that
there
were
nearly
62
million
women
between
the
ages
of
15
and
44.
The
Center
for
Disease
Control
states
that
in
2003,
70.9
percent
of
new
mothers
nursed
in
the
hospital.
Out
of
4.03
million
babies,
that
means
that
2.86
million
were
breast­
fed
within
their
first
few
days
of
life.
This
totals
up
to
68.89
million
sensitive
humans
being
exposed
to
Hg
on
a
daily
basis.
Breast­
fed
infants
were
counted
twice,
as
they
were
exposed
both
in
utero
and
while
breast
feeding.
Thus,
23
percent
of
the
total
U.
S.
population
of
297.3
million
is
potentially
at
risk
from
eating
fish.
Second,
local
fish
have
been
tested
and
found
to
contain
Hg
in
levels
that
exceed
EPA
recommendations.
Advisories
have
been
issued
for
local
fish
consumption,
not
just
by
the
commenter
but
also
by
44
states
in
the
Union.
Locally
caught
fish
probably
comprise
95
percent
of
all
fish
eaten
by
Band
members.
If
EEI
can
include
such
egregiously
incorrect
statements
as
these,
the
rest
of
its
comments
are
suspect.

EEI
further
claims,
"
Most
Americans,
however,
eat
little
fish.
Half
of
all
Americans
eat
no
fish
whatsoever
and,
of
those
who
do,
the
weekly
average
consumption
is
about
one
quarter
pound.
Nearly
all
this
fish
is
store­
bought
ocean
fish,
which
is
unlikely
to
contain
much
Hg
emitted
from
U.
S.
sources".
This
statement
is
totally
erroneous
and
downright
bizarre.
Catherine
O'Neill's
article
refutes
this
statement
with
data
from
NHANES
III,
which
asserts
"
roughly
88
percent
of
all
adults
consume
fish
and
shellfish
at
least
once
a
month;
and
1
percent
consume
fish
daily."
This
study
also
shows
that
composition
of
the
group
who
eats
fish
frequently
differs
greatly
from
the
group
who
eats
fish
less
often.
In
short,
Americans
in
minority
groups
consume
fish
far
more
often
than
white
respondents
do,
putting
these
groups
at
higher
risk.

The
EEI
comments
also
assert
that
since
a
recent
University
of
Rochester
study
has
concluded
that
children
in
the
Seychelles
Islands
appear
to
be
unaffected
by
Hg
exposure,
the
utility
industry
should
be
let
off
the
hook.
As
I'm
sure
EEI
would
feel
if
the
positions
were
reversed,
the
results
of
one
study
cannot
totally
refute
the
contradictory
findings
of
many
other
studies.
Although
the
results
of
the
Seychelles
study
are
surprising
and
show
the
need
for
further
research,
the
whole
of
Hg
study
and
regulation
can't
be
abandoned
over
it.
In
fact,
the
National
Research
Council
of
the
U.
S.
National
Academy
of
Sciences
has
concluded
that
the
Faroe
Islands
study
is
more
appropriate
for
use
than
the
Seychelles
study
for
deriving
the
Reference
Dose.
The
commenter
urged
EPA
to
follow
this
advice
rather
than
the
biased
comments
from
EEI.

The
EEI
supports
the
statement
by
the
American
Medical
Association
that
"
because
of
the
wide
variations
in
the
concentrations
of
Hg
in
fish
and
shellfish,
it
is
possible
to
have
the
nutritional
benefits
of
moderate
fish
consumption
and
avoid
fish
high
in
Hg."
While
this
may
be
true
of
the
typical
consumer,
subsistence
level
people
do
not
have
the
option
of
spending
money
9­
229
on
store­
bought
fish
or
restaurant
meals.
The
fish
available
to
them
are
native
species
that
come
from
local
waters.

So,
in
summary,
the
commenter
did
not
agree
with
the
fish
consumption
rates
used
in
this
rulemaking.
The
Water
Quality
Criterion
uses
a
consumption
rate
of
17.5
g/
day
(
or
lower),
which
has
been
shown
to
be
too
low
for
tribal
people.
The
commenter
also
was
suspicious
of
the
consumption
rates
given
in
Peterson,
et.
al.,
because
they
do
not
agree
with
data
obtained
from
GLIFWC
and
the
Leech
Lake
Band.
The
commenter
had
not
had
sufficient
time
to
thoroughly
review
the
Peterson
study,
the
commenter
are
simply
wary
of
its
results.
It
could
be
that
the
people
surveyed
have
already
changed
their
consumption
habits
to
account
for
Hg
contamination.
If
so,
it
is
an
example
of
an
indirect
curtailing
of
treaty
rights
and
is
unacceptable.
The
relatively
low
consumption
patterns
evidenced
by
the
study
may
also
be
a
function
of
efforts
made
by
the
Wisconsin
Department
of
Natural
Resources
and
by
the
specific
tribal
governments
to
inform
people
of
consumption
advisories.
As
an
Environmental
Justice
aside,
let
me
point
out
the
Peterson
study's
finding
that
Hg
levels
were
highest
among
the
unemployed.

The
NODA
also
seeks
comment
on
EPA's
plan
to
use
National
Fish
Tissue
Study
(
NFTS)
values
for
methylHg
concentrations
in
fish.
EPA
favors
the
use
of
NFTS
data
over
National
Listing
of
Fish
Advisories
(
NLFA)
data
because
the
former
were
gathered
by
random
sample
while
the
NLFA
data
are
gathered
from
areas
of
increased
angling
activity
and
from
areas
of
suspected
contamination
(
as
explained
in
the
NODA).
The
commenter
believed
this
reasoning
is
exactly
backward.
If
one
wants
to
protect
the
most
sensitive
members
of
the
population,
worst­
case
scenarios
must
be
considered.
That
means
looking
at
those
who
eat
the
highest
quantities
of
fish
and
those
who
eat
the
most
heavily
contaminated
fish.
The
commenter
believed
this
is
highly
appropriate
based
on
a
public
health
perspective.
Second,
GLIFWC
data
suggests
levels
of
contamination
higher
than
those
put
forth
by
EPA.

Response:

EPA
agrees
that
for
some
situations
(
e.
g.,
commenter
examples)
the
value
142.4
may
be
an
underestimate
of
fish
consumption.
This
is
the
value
that
the
Agency
recommends
in
its
water
quality
standards
program
to
States
with
high­
consuming
sub­
populations,
in
lieu
of
site­
specific
data
when
those
states
are
faced
with
developing
a
water
quality
standard
for
methylmercury
that
is
protective
of
the
fish
consumption
use
of
state
waters
demonstrated
by
those
subpopulations
Where
a
state
has
local
information
indicating
higher
rates
of
fish
consumption
than
142.4,
it
is
recommended
that
they
use
it.
In
the
benefits
analyses
performed
for
this
rule,
several
consumption
scenarios
were
considered
based
on
the
available
data
pertinent
to
the
population
modeled
(
recreational
anglers),
but
the
value
of
142.4
g/
day
was
not
used.

EPA
has
included
four
potentially
high­
risk
populations
in
the
RIA,
including:
(
a)
highend
recreational
fisher
anglers
(
with
consumption
rates
at
or
above
the
95th
percentile
for
this
group),
(
b)
economically
disadvantaged
high­
end
consumers
with
poverty­
status
income
and
fish
consumption
rates
at
or
above
the
95th
percentile
for
freshwater
anglers,
(
c)
Hmong
in
Minnesota
and
Wisconsin
and
(
d)
Chippewa
in
Minnesota,
Wisconsin,
and
Michigan.
These
9­
230
special
population
are
intended
to
provide
coverage
for
groups
of
individuals
who
through
choice,
necessity
or
socio­
cultural
practices
consume
relatively
high
levels
of
self­
caught
freshwater
fish.
Inclusion
of
these
four
special
populations
is
also
intended
to
support
consideration
of
distributional
equity
in
relation
to
EGU­
based
environmental
regulation
(
i.
e.,
would
a
subset
of
the
US
population
benefit
disproportionately
from
regulations
to
reduce
mercury
emissions
from
EGUs)?

Fish
consumption
rates
for
all
four
special
populations
have
been
developed
based
on
peer­
reviewed
survey
data
that
are
representative
of
the
particular
group
of
interest.
In
the
case
of
the
Chippewa,
EPA
has
used
a
mean
value
obtained
from
the
literature
(
see
RIA
Chapter
10
for
additional
details).
However,
it
was
not
possible
to
identify
a
high­
end
percentile
consumption
rate
based
on
peer­
reviewed
literature
and
consequently,
the
mean
consumption
rate
was
used
in
the
benefits
analysis
without
consideration
for
variability
in
fish
consumption
rates
across
individuals.
However,
in
response
to
information
provided
in
NODA
comments
(
including
that
provided
by
this
commenter),
EPA
has
conducted
a
sensitivity
analysis
for
highend
fish
consumption
by
the
Chippewa
population
using
(
a)
the
maximum
delta
fish
tissue
concentration
(
for
Walleye)
modeled
in
states
where
Chippewa
are
located
for
the
RIA
for
Option
1
and
Option
2
(
i.
e.,
the
maximum
change
in
MeHg
fish
tissue
concentrations
modeled
in
Michigan,
Wisconsin
or
Minnesota
under
CAMR
Options
1
and
2)
and
(
b)
the
maximum
seasonal
fish
consumption
rate
provided
in
the
NODA
comments
(
i.
e.,
393.8
g/
day).
The
results
suggest
that
total
IQ
reductions
under
Option
1
and
2,
even
under
these
conservative
assumptions
(
i.
e.,
highest
change
in
mercury
fish
tissue
concentrations
under
Option
1
and
Option
2
and
the
highest
seasonal
fish
consumption
rate),
are
relatively
low
at
0.32
IQ
points
per
child.
This
relatively
low
IQ
benefit
for
this
conservative
scenario
reflects
the
fact
that,
while
states
where
the
Chippewa
are
located
may
have
relatively
high
absolute
(
total)
MeHg
concentrations
in
target
fish
species,
modeled
EGU
deposition
over
these
areas
is
relatively
low
and
consequently,
CAMR
is
likely
to
produce
relatively
small
changes
in
mercury
fish
tissue
concentrations
compared
with
other
areas
where
EGU
deposition
is
higher
(
e.
g.,
the
Ohio
river
valley).
These
findings
argue
against
a
distributional
equity
concern
for
the
Chippewa
in
this
portion
of
the
study
area
(
although
this
conclusion
needs
to
be
considered
in
the
context
of
the
overall
precision
and
specificity
of
the
benefits
model
used
in
this
RIA
which
is
not
intended
for
site­
specific
analysis
and
was
developed
for
application
at
the
regional­
level).

The
National
Research
Council
has
identified
fish
consumption
as
the
primary
pathway
of
concern
for
exposure
to
methylmercury
in
the
United
States
and
consequently,
the
RIA
has
focused
on
this
exposure
pathway
and
has
not
considered
other
dietary
categories
such
as
nonfish
meat
and
vegetables.
EPA
does
recognize
that
additional
dietary
pathways
may
contribute
to
overall
methylmercury
exposure,
however
these
pathways
are
likely
to
be
overshadowed
by
the
fish
consumption
pathway.
Even
in
the
case
of
subsistence
sub­
populations
who
may
obtain
a
significant
amount
of
their
protein
and/
or
calories
from
self­
produced
food
stuffs,
fish
is
expected
to
represent
the
dominant
methyl­
mercury
source.
In
the
case
of
ducks,
although
they
may
have
methlymercury
concentrations
that
match
fish
concentrations
(
although
as
the
commentor
noted,
these
studies
have
limitations),
because
ducks
are
not
likely
to
consume
upper­
trophic
level
fish,
their
mercury
levels
are
likely
to
be
low
compared
with
upper
trophic
9­
231
level
(
predator)
fish.
For
these
reasons,
EPA
does
not
believe
that
significant
uncertainty
is
introduced
into
either
the
primary
benefits
analysis,
or
consideration
of
distributional/
equity
issues
through
exclusion
of
these
non­
fish
dietary
pathways.

The
RIA
used
measured
mercury
fish
tissue
data
collected
by
both
states
(
National
Listing
of
Fish
Advisories)
and
the
EPA
(
National
Fish
Tissue
Survey)
and
was
not
based
on
generalized
data
on
mercury
concentrations
in
commercial
fish.
While
not
providing
complete
coverage
for
all
areas
potentially
fished
by
modeled
populations
including
Native
American
populations
such
as
the
Chippewa,
this
fish
tissue
data
set,
does
provide
a
reasonable
degree
of
coverage
for
mercury
fish
tissue
contamination
in
the
context
of
conducting
a
benefits
analysis.
In
the
case
of
the
Native
American
case
study
modeled
for
the
RIA
(
the
Chippewa),
exposure
modeling
was
based
on
(
a)
fish
tissue
concentrations
for
waterbodies
in
the
potential
fishing
activity
zone
of
the
Chippewa
in
Michigan
and
Minnesota
and
(
b)
fishing
activity
modeling
that
reflects
reasonable
assumptions
regarding
trip
travel
distances
associated
with
fishing
activity
by
the
Chippewa.
In
other
words,
the
benefits
analysis
was
not
based
on
generalized
assumption
regarding
mercury
contamination
in
commercial
fish,
but
rather
on
measured
mercury
fish
tissue
concentrations
measured
in
waterbodies
likely
accessed
by
this
population.

Although
EPA
considers
inclusion
of
the
NFTS
data
extremely
valuable
in
providing
additional
coverage
for
the
study
area,
it
is
important
to
note
that
the
majority
of
measured
fish
tissue
concentrations
were
contributed
by
the
NLFA
and
not
by
the
NFTS.
This
fact
partially
addresses
the
commentor's
concerns
(
i.
e.,
the
benefits
analysis
primarily
reflects
NLFA
data
with
a
smaller
relative
contribution
from
the
NFTS
dataset).
EPA
agrees
with
the
commentor
that
NLFA
data
(
when
reflecting
areas
of
increased
fishing
activity)
would
be
preferable
to
randomly
collected
data
for
purposes
of
supporting
a
benefits
analysis.
However,
given
the
patchy
nature
of
the
NLFA
and
the
variety
of
sampling
protocols
used
by
different
states
in
collecting
data
included
in
the
NLFA,
EPA
considers
the
NFTS
data
to
be
very
useful
in
filling
in
gaps
in
coverages
and
in
providing
a
consistent
randomly­
sampled
dataset
to
augment
the
purposively
sampled
data
contained
in
the
NLFA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
presents
an
important
source
of
information.
Figure
K1
shows
the
distribution
of
hair
Hg
values
of
56
pregnant
women
sampled
from
12
different
native
communities
across
Alaska.
This
2002
survey
by
the
State
of
Alaska
Epidemiology
Office
confirms
that
on
average
Alaskan
native
pregnant
women
(
with
a
mean
hair
Hg
value
of
0.6
ppm)
consumed
more
fish
than
other
average
U.
S.
women
(
who
have
a
mean
hair
Hg
value
of
about
0.2
ppm
based
on
the
ongoing
CDC's
NHANES
database).
It
is
also
clear
from
Figure
K1
(
see
e­
docket
OAR­
2002­
0056­
5423),
based
on
the
examination
of
8
Aleutian
mummies
dated
to
about
550
years
ago,
that
the
native
Alaskans
had
long
been
naturally
exposed
to
significantly
large
levels
of
MeHg
through
fish
and
marine
mammals
in
their
traditional
diets
without
any
plausible
"
contamination"
by
power
plant
Hg
emissions.

Exposure
to
MeHg
in
Alaska:
Today
Versus
550
Years
Ago.
Today's
distribution
with
a
9­
232
mean
of
0.6
ppm.
Compare
0.6
ppm
to
the
mean
level
of
MeHg
in
550­
year
old
with
one
mummy
with
MeHg
as
high
as
4.6
ppm.
Aleutian
mummies:
1.2
ppm
(
mean
of
4
adults)
1.44
ppm
(
mean
of
4
infants).
State
of
Alaska
Epidemiology
Bulletin
No.
29(
December
11,
2002).

Regarding
other
native
populations
in
Eastern
North
America,
field
records
from
Nunavik,
Quebec
(
Figure
K2,
see
e­
docket
OAR­
2002­
0056­
5423)
suggest
that
the
prenatal
exposure
level
of
MeHg,
lead
and
persistent
organic
pollutants
(
or
POPs)
in
Inuit
infants
born
between
1994
and
2001
has
declined
significantly.
The
authors
of
this
new
research
paper
concluded
that
"
A
significant
reduction
of
lead
and
Hg
concentrations
was
found,
but
there
was
no
clear
linear
or
exponential
trend.
The
decreases
observed
could
be
explained
by
a
decrease
in
food
contamination,
by
changes
in
dietary
habits,
or,
most
likely
by
a
combination
of
both.
Although
questions
remain
as
to
the
exact
causes
of
decline,
it
is
encouraging
to
observe
such
an
improvement
in
prenatal
exposure
for
this
highly
exposed
population."

Concentrations
of
Hg,
lead
and
persistent
organic
pollutants
in
umbilical
cord
blood
of
Inuit
infants
born
in
Nunavik,
Quebec
have
been
decreasing
from
1994
to
2001
"
A
significant
reduction
of
lead
and
Hg
concentrations
was
found,
but
there
was
no
clear
linear
or
exponential
trend.
The
decreases
observed
could
be
explained
by
a
decrease
in
food
contamination,
by
changes
in
dietary
habits,
or,
most
likely
by
a
combination
of
both.
Although
questions
remain
as
to
the
exact
causes
of
decline,
it
is
encouraging
to
observe
such
an
improvement
in
prenatal
exposure
for
this
highly
exposed
population."

Equally
important
are
explanations
and
cautions
from
this
team
of
Laval
University
Medical
Center
researchers
in
an
earlier
publication
(
Dewailly
et.
al.,
2001,
Archives
of
Environmental
Health,
vol.
56,
350­
357):

"
According
to
recommendations
formulated
by
the
World
Health
Organization
(
WHO),
no
more
than
5
percent
of
individuals
in
a
population
should
display
a
methylmercury
concentration
that
exceeds
1000
nmol/
L
[
or
converted
to
200

g/
L
MeHg
in
blood].
Concentrations
of
total
mercury
noted
in
present
study
did
not
exceed
560
nmol/
L
[
112

g/
L].
WHO
issued
more
stringent
recommendations
for
pregnant
women,
stating
that
not
more
than
5
percent
of
this
subgroup
should
exhibit
methylmercury
concentration
above
400
nmol/
L
[
80

g/
L].
In
our
survey,
no
women
of
childbearing
age
exhibited
concentrations
of
this
magnitude.
Recent
data
from
Faroe
Island
suggest
that
the
neurologic
status
of
children
can
be
affected
by
low­
level
prenatal
exposure
to
mercury.
There
are,
however,
major
differences
between
the
diet
of
Faroese
and
the
diet
of
Inuits,
and
care
must
be
exerted
before
one
concludes
that
Inuit
children
are
at
risk.
[
I]
n
view
of
the
high
selenium
intake
[
in
the
diets
of
the
Inuit
population
from
consumption
of
mattak
(
beluga
whale
skin)
which
is
about
2.4
times
higher
than
that
measured
in
the
Farose],
which
may
counteract
methylmercury­
induced
toxicity,
local
public
health
authorities
did
not
recommend
reducing
seafood
consumption."

If
EPA
has
serious
concerns
for
native
populations,
it
should
focus
on
the
fact
that
instead
of
advancing
health
and
safety
for
these
peoples,
Hg
warnings
are
already
causing
harm.
John
9­
233
Middaugh,
State
Epidemiologist
of
Alaska,
recently
warned
FDA:

"
Advisories
based
upon
risk
assessment
without
consideration
of
well­
established
public
health
benefits
of
fish
consumption
have
great
potential
to
harm
public
health
if
reductions
in
fish
consumption
occur."

Middaugh
reported
that
many
native
Alaskan
communities
abandoned
traditional
fish
diets
since
the
FDA's
2001
Hg
advisory,
with
a
subsequent
increase
in
diabetes,
heart
disease,
and
vitamin
A
and
D
deficiencies.

Response:

As
described
in
other
responses,
the
Agency
has
high
confidence
in
the
RfD
for
methylmercury.
EPA
encourages
the
public
to
vary
the
species
and
sources
of
fish
in
order
to
obtain
the
benefits
of
fish
consumption
while
avoiding
elevated
exposures
to
methylmercury.
The
fish
advisory
developed
jointly
with
the
Food
and
Drug
Administration
emphasizes
the
benefits
of
including
fish
in
a
healthy
diet
while
informing
the
public
on
ways
to
reduce
methylmercury
exposure
(
http://
www.
epa.
gov/
waterscience/
fishadvice/
advice.
html).

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
supports
EPA's
intention
to
properly
apply
information
from
the
ongoing
CDC's
NHANES
database
(
which
some
at
EPA
have
not
done),
but
must
stress
that
no
women
(
Figure
L1,
see
e­
docket
OAR­
2002­
0056­
5423)
or
children
(
Figure
L2,
see
e­
docket
OAR­
2002­
0056­
5423)
in
the
current
NHANES
survey
are
actually
harmed
by
the
levels
of
Hg
in
their
blood
from
fish
consumption.

The
commenter
will
delay
comments
on
the
ultra­
conservative
nature
of
the
MeHg
RfD
value
set
by
EPA,
as
shown
in
Figures
L1
and
L2,
to
comment
(
O)
(
see
e­
docket
OAR­
2002­
0056­
5423).
The
commenter
will
also
confirm
in
comment
(
O)
that
EPA's
MeHg
RfD
was
derived
from
the
Faroe
Islands
Children
Study
that
was
plagued
by
contaminants
like
PCBs
and
DDT
through
consumption
of
pilot
whale
products
and
hence
is
widely
recognized
in
professional
circles
as
incompatible
with
or
irrelevant
to
the
U.
S.
consumption
profile
of
a
wide
variety
of
fish
(
i.
e.,
excluding
whale
products).

Response:

In
deriving
the
reference
dose
for
methylmercury,
EPA
relied
on
an
integrated
analysis
involving
three
studies.
These
longitudinal,
developmental
studies
were
conducted
in
the
Seychelles
Islands,
the
Faroe
Islands,
and
New
Zealand.
The
Seychelles
study
yielded
scant
evidence
of
impairment
related
to
in
utero
methylmercury
exposure,
whereas
the
other
two
studies
found
dose­
related
effects
on
a
number
of
neuropsychological
endpoints.
In
the
assessment
developed
for
the
RfD,
emphasis
is
placed
on
the
results
of
the
Faroe
Islands
study,
the
larger
of
the
two
studies
that
identified
methylmercury­
related
developmental
neurotoxicity.
9­
234
Supporting
evidence
from
the
New
Zealand
study
provides
assurance
that
choosing
this
focus
is
the
appropriate
strategy
for
protecting
public
health.
Conclusions
from
the
National
Research
Council
review
of
methylmercury
support
this
use
of
the
Faroes
Island
study
and
disagree
with
the
suggestion
of
a
role
for
PCBs
in
the
neurological
effects
observed
(
NRC.
2000.
Toxicological
Effects
of
Methylmercury.
National
Academy
Press.),
saying
that
"
The
committee
concludes
that
there
do
not
appear
to
be
any
serious
flaws
in
the
design
and
conduct
of
the
Seychelles
Islands,
Faroe
Islands,
and
New
Zealand
studies
that
would
preclude
their
use
in
a
risk
assessment."

The
Agency's
derivation
of
the
RfD
also
followed
the
National
Research
Council
recommendation
for
an
overall
composite
uncertainty
factor
of
no
less
than
10.

In
summary,
the
Agency's
overall
confidence
in
this
RfD
assessment
is
high.
Three
high­
quality
epidemiological
studies
published
since
the
last
derivation
of
the
oral
RfD
in
1995,
have
been
included
in
the
analysis.
Two
of
the
studies
(
Faroe
Islands,
New
Zealand)
reported
effects
on
a
number
of
neuropsychological
endpoints,
whereas
the
third
(
Seychelles
Islands)
reported
no
effects
related
to
in
utero
exposure
to
methylmercury.
Benchmark
dose
analysis
of
a
number
of
endpoints
from
both
the
New
Zealand
and
Faroe
Islands
study
converged
on
an
RfD
of
0.1
µ
g/
kg­
day,
as
did
the
integrative
analysis
combining
all
three
studies.
Although
there
was
coexposure
to
PCBs
in
the
Faroe
Islands
study,
statistical
analysis
indicated
that
the
effects
of
PCBs
and
methylmercury
were
independent.
Moreover,
benchmark
dose
analysis
of
the
endpoints
that
were
significantly
associated
with
methylmercury
yielded
RfDs
that
were
approximately
the
same
when
corrected
for
PCBs.
The
same
was
true
when
the
analysis
was
or
based
on
the
subset
of
the
cohort
in
the
lowest
tertile
with
respect
to
PCB
levels,
as
compared
with
the
full
cohort.
These
findings
provide
further
evidence
that
the
identified
effects
are
in
fact
the
result
of
methylmercury
exposure.

Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
with
regard
to
step
four
of
the
proposed
revised
benefits
assessment
methodology,
EPA
has
not
adequately
explained
how
it
intends
to
supplement
data
from
the
National
Listing
of
Fish
Advisories
with
data
from
the
National
Study
of
Chemical
Residues
in
Lake
Fish
Tissue,
let
alone
why
such
supplementation
is
necessary.
The
commenter
added
that
EPA
has
likewise
failed
to
explain
why
it
is
appropriate
to
develop,
in
the
context
of
the
CAMR,
national
estimates
of
the
mean
concentrations
of
268
chemicals
in
fish
tissue
from
lakes
and
reservoirs
across
the
U.
S.
The
commenter
stated
that
EPA
should
not
use
national
estimates
to
underestimate
Hg
concentrations,
or
Hg
exposure,
in
any
particular
region
or
area
of
the
country.

Response:

The
benefits
analysis
completed
for
the
RIA
is
not
intended
to
model
local­
scale
changes
in
fish
tissue
concentrations
and
exposures
in
support
of
site­
specific
risk
analysis.
Instead,
9­
235
modeling
conducted
for
the
RIA
is
intended
to
capture
generalized
regional
changes
in
methlmercury
exposure
resulting
from
reductions
in
power
plant
mercury
emissions
in
order
to
support
a
national­
scale
benefits
assessment
focusing
on
the
37­
State
eastern
US
study
area.
For
additional
details
on
the
benefits
analysis
modeling
framework
see
Section
10
of
the
RIA.

Although
EPA
is
not
conducting
local­
scale
modeling
of
mercury
fish
tissue
concentration
changes
resulting
from
decreased
mercury
deposition,
the
modeling
framework
used
in
this
RIA
is
believed
to
have
sufficient
precision
to
generate
reasonably
accurate
benefits
estimates.
Specifically,
36km2
CMAQ
grid
cell
air
modeling
results
are
used
to
project
deposition
changes
over
individual
fish
tissue
sampling
locations
for
purposes
of
predicting
changes
in
fish
tissue
concentrations
related
to
emissions
reductions
from
power
plants.
In
addition,
recreational
anglers
and
additional
potential
high­
exposure
populations
(
e.
g.,
highend
consumers
and
Chippewa)
are
modeled
using
relatively
spatially­
differentiated
behavioral
and
exposure
models
which
consider
both
the
distribution
of
fishers
across
the
study
area
(
at
the
US
Census
block
group,
or
8­
digit
HUC
level)
and
the
potential
behavior
of
fishers
in
accessing
different
areas
or
zones
for
fishing.
This
modeling
framework
is
believed
to
provide
sufficient
spatial
resolution
in
characterizing
regional
patterns
of
population­
level
exposure
to
mercury
through
fishing
activity
(
and
consumption)
to
support
the
benefits
analysis.
For
additional
detail
on
the
benefits
modeling
framework,
see
Section
10
of
the
RIA.

Although
EPA
considers
inclusion
of
the
NFTS
data
extremely
valuable
in
providing
additional
coverage
for
the
study
area,
it
is
important
to
note
that
the
majority
of
measured
fish
tissue
concentrations
were
contributed
by
the
NLFA
and
not
by
the
NFTS.
This
fact
partially
addresses
the
commentor's
concerns
(
i.
e.,
the
benefits
analysis
primarily
reflects
NLFA
data
with
a
smaller
relative
contribution
from
the
NFTS
dataset).
EPA
agrees
with
the
commentor
that
NLFA
data
(
when
reflecting
areas
of
increased
fishing
activity)
would
be
preferable
to
randomly
collected
data
for
purposes
of
supporting
a
benefits
analysis.
However,
given
the
patchy
nature
of
the
NLFA
and
the
variety
of
sampling
protocols
used
by
different
states
in
collecting
data
included
in
the
NLFA,
EPA
considers
the
NFTS
data
to
be
very
useful
in
filling
in
gaps
in
coverages
and
in
providing
a
consistent
randomly­
sampled
dataset
to
augment
the
purposively
sampled
data
contained
in
the
NLFA.

The
procedure
used
to
generate
a
single
standardized
fish
tissue
dataset
for
use
in
supporting
the
benefits
analysis
using
data
from
both
the
NLFA
and
NFTS
datasets
is
described
in
the
CAMR
RIA.
Regarding
the
rationale
for
combining
the
two
datasets,
EPA
believes
that
the
NLFA
provides
a
large
number
of
fish
tissue
samples
with
some
bias
for
areas
likely
fished
(
which
is
advantageous
in
supporting
the
benefits
analysis),
while
the
NFTS,
with
its
statistically
random
sampling
strategy,
provides
consistent
spatial
coverage
for
waterbodies
across
the
study
area
and
in
that
way,
can
fill
in
gaps
left
by
the
NLFA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
the
development
of
an
assessment
protocol
that
melds
regional
fish
consumption
patterns
with
the
distribution
of
MeHg
9­
236
concentrations
in
fish
is
an
immensely
challenging
and
complex
undertaking.
Existing
fish
tissue
samples
must
be
normalized
to
account
for
differences
in
fish
age,
length,
etc.
Fish
consumption
data
must
be
developed
at
the
regional
level
to
reflect
differences
in
the
types
of
species
consumed,
the
source
of
those
fish
(
including
whether
they
come
from
highly
productive
waterbodies
or
not)"
and
the
amount
of
fish
consumed.
The
commenter
does
not
see
how
the
analyses
described
in
Step
4
could
be
completed,
in
any
scientifically
valid
way,
by
March
15,
2005.

EPA's
request
for
comments
on
the
incorporation
of
the
National
Listing
of
Fish
Advisories'
(
NLF
A)
and
National
Fish
Tissue
Study's
(
NFTS)
fish
tissue
data
into
the
National
Descriptive
Model
of
Mercury
and
Fish
Tissue
(
NDMMFT)
suffers
from
EPA's
failure
to
make
the
pertinent
material
available
in
the
docket.
EPA's
promise
to
place
these
materials
in
the
docket
"
when
available"
makes
it
difficult,
if
not
impossible,
to
respond
to
EPA's
questions
in
a
detailed
manner.
EPA
should
not
use
NDMMFT
in
a
benefits
analysis
without
further
public
comment.

As
for
the
fish
consumption
rates
incorporated
into
EPA's
MeHg
fish
tissue
criterion,
they
are
conservative.
The
default
consumption
rate
of
17.5
grams/
day
is
based
on
a
value
representing
the
90th
percentile
of
the
value
for
freshwater
and
estuarine
fish
from
a
1995­
96
study
conducted
by
the
Department
of
Agriculture.
Default
fish
intake
rates
for
recreational
and
subsistence
fishers
of
17.5
grams/
day
and
142.4
grams/
day
respectively
are
based
on
values
representative
of
the
90th
and
99th
percentiles
of
the
general
population.
The
fish
tissue
criterion
is
designed
to
be
highly
protective,
not
to
accurately
predict
fish
consumption
rates
in
a
way
that
would
be
realistic
for
a
benefits
analysis.

Response:

EPA
has
implemented
a
methodology
for
the
RIA
that
accomplishes
most
of
the
technical
tasks
noted
by
the
commenter.
For
the
RIA,
EPA
has
used
the
NDMMFT
statistical
model
to
effective
standardize
the
measured
fish
tissue
concentrations
with
regard
to
size
(
length)
and
species.
This
produces
a
standardized
(
diet
relevant)
set
of
fish
species
and
lengths
for
use
in
the
benefits
analysis
and
avoids
the
inclusion
of
non­
diet
relevant
sizes/
species
in
exposure
modeling.
Regarding
fish
consumption
rates,
EPA
acknowledges
that
regional
differences
are
likely
to
exist
both
for
recreational
anglers
as
well
as
high­
consumption
(
subsistence)
populations.
However,
with
regard
to
recreational
anglers,
EPA
could
not
identify
regional­
or
local­
scale
studies
in
the
literature
with
sufficient
collective
coverage
to
allow
comprehensive
modeling
of
the
37­
State
study
area
without
leaving
large
gaps
in
geographic
coverage
(
i.
e.,
individual
studies
covering
smaller
geographic
areas
or
watersheds
were
identified,
but
they
could
not
be
combined
to
provide
a
cohesive
coverage
for
the
study
area).
Ultimately,
the
consumption
rates
for
the
recreational
angler
that
were
used
in
the
RIA
were
obtained
from
peer­
reviewed
studies
and
are
representative
of
general
trends
in
behavior
for
this
group.
For
special
populations
(
i.
e.,
the
Chippewa
and
Hmong),
consumption
rates
based
on
peer­
reviewed
studies
focusing
on
these
specific
ethnic
groups
were
used.
The
RIA
contains
an
expanded
description
of
our
application
of
the
NDMMF.
More
information
about
the
model
itself
can
be
9­
237
found
at
http://
pubs.
water.
usgs.
gov/
sir20045199/.

5.
Step
5:
Assessing
the
relationship
between
reductions
in
human
exposure
and
improvements
in
public
health.
EPA
sought
comment
on
all
aspects
of
its
proposed
revised
methodology
for
estimating
the
relationship
between
reductions
in
methylmercury
exposure
and
improvements
in
health.
In
particular,
EPA
sought
comment
on:
(
1)
the
focus
on
neurodevelopment
health
of
children;
(
2)
the
selection
of
IQ
as
an
endpoint
for
quantification
of
neurodevelopmental
effects
and
whether
it
is
an
appropriate
endpoint
for
benefits
analysis;
(
3)
whether
other
neurodevelopmental
effects
can
be
quantified
and
are
amendable
to
economic
valuation;
(
4)
whether,
and
if
so
how,
data
from
the
Faroe
Islands,
New
Zealand,
and
Seychelles
Islands
studies
can
be
integrated
for
the
benefits
analysis;
the
choice
of
the
K=
1
model
for
estimating
the
relationship
between
exposure
and
IQ
and
practical
alternatives
to
that
approach;
and
the
appropriateness
of
using
a
linear
dose­
response
model
given
the
EPA's
reference
dose,
which
assumes
a
threshold
does
below
which
there
is
not
likely
to
be
an
appreciable
risk
of
deleterious
effects
during
a
lifetime.

Comment:

The
commenter
(
OAR­
2002­
0056­
5542)
has
historically
been
united
in
its
advocacy
that
federal
regulatory
agencies
such
as
the
EPA
must
use
sound
science
and
risk
prioritization.
The
commenter
has
supported
"
scientifically
sound
risk
analysis;
risk­
based
prioritization;
benefit­
cost
analysis;
flexible,
efficient,
cost­
effective
risk
management;
and
public
participation
in
all
phases
of
the
process."
The
commenters
stated
that
their
policy
also
expressly
supports
a
conclusion
made
by
EPA
in
its
document,
"
Reducing
Risk:
Setting
Priorities
and
Strategies
for
Environmental
Protection,
2
September
1990,"
which
states:

There
are
heavy
costs
involved
if
society
fails
to
set
environmental
priorities
based
on
risk.
If
finite
resources
are
expended
on
lower­
priority
problems,
at
the
expense
of
higher­
priority
risks,
then
society
will
face
needlessly
high
risks.
If
the
priorities
are
established
based
on
the
greatest
opportunities
to
reduce
risk,
total
risk
will
be
reduced
in
a
more
efficient
way,
lessening
threats
to
both
public
health
and
local
and
global
ecosystems.

The
commenter
was
concerned
that
the
EPA
is
chasing
a
Hg
emissions
reduction
goal
that
is
a
low­
priority
problem
that
represents
little
or
no
risk,
but
would
nevertheless
be
squandering
finite
economic
resources
that
are
needed
for
economic
growth
and
for
meeting
higher
priority
risks.
Since
the
EPA's
Hg
decisions
could
have
the
effect
of
dramatically
reducing
coal
use
in
the
U.
S.,
generators
trying
to
fulfill
the
nation's
growing
need
for
electricity
would
then
be
forced
from
abundant
coal
to
either
scarce
natural
gas
or
future
nuclear
power.

The
commenter
noted
that
the
current
EPA
has
access
to
almost
a
decade
more
research
regarding
both
the
real
science
of
public
health
exposure
to
U.
S.
power
plant
emissions
of
9­
238
elemental
Hg
and
to
the
net
public
health
benefits
of
eating
fish,
the
primary
source
of
Hg
accumulation
in
the
body.
The
commenter
believed
that
the
EPA
must
correct
the
refuted
science
that
was
the
foundation
of
the
Agency's
reference
dose,
and
therefore
the
foundation
of
the
agency's
proposed
Hg
rule.

Under
the
sound
science
category,
the
commenter
believed
the
central
issues
for
the
agency
are
whether
any
level
of
MeHg
consumption
by
humans
was
acceptable;
and
whether
reducing
elemental
Hg
emissions
from
U.
S.
power
plants
will
have
any
measurable
impact
on
the
MeHg
levels
in
fish
broadly
consumed
by
the
American
public.
Many
epidemiological
studies
have
been
undertaken
since
the
EPA
first
picked
its
reference
dose
level
that
show
almost
uniformly
that
some
levels
of
MeHg
in
humans
are
acceptable.
Further,
natural
levels
of
MeHg,
as
well
as
the
deposition
of
elemental
Hg
from
sources
outside
the
U.
S.,
ensure
that
even
closing
U.
S.
coal­
fired
power
plants
will
not
affect
the
quantities
of
MeHg
in
fish
that
the
U.
S.
population
ingests.

As
carefully
documented
in
the
comments
filed
by
the
Utility
Air
Regulatory
Group
(
URAG)
on
June
29,
2004,
the
EPA
made
a
number
of
serious
procedural
mistakes
and
deviations
from
its
customary
and
or
appropriate
processes
in
order
to
conclude
that
Hg
emissions
from
coal­
fired
power
plants
were
adversely
affecting
public
health.
The
nation
is
facing
many
real
risks
of
terrorism
and
natural
events,
such
as
infectious
diseases,
hurricanes,
volcanoes
or
tsunamis.
Manufacturers
in
particular
are
facing
intense
and
sometimes
unfair
international
competition
and
escalating
structural
costs
at
home
from
an
out­
of­
control
legal
system,
skyrocketing
pensions
and
health
benefit
costs,
high
corporate
taxation,
high
energy
costs
and
over­
zealous
regulation.
The
nation,
and
certainly
the
manufacturing
sector
(
which
still
accounts
for
13
percent
of
the
U.
S.
economy),
can
ill
afford
expensive
regulations
promulgated
in
order
to
chase
minor
or
negative
net
risks
to
public
health.

The
EPA
itself
has
stated
that
there
is
a
reference
dose
level
of
MeHg
in
the
body
"
below
which
there
is
no
danger
to
human
health."
Other
entities,
including
the
World
Health
Organization,
the
U.
S.
Federal
Food
and
Drug
Administration
(
FDA),
the
Agency
for
Toxic
Substances
and
Disease
Registry
(
ATSDR),
Health
Canada
(
Canada's
FDA)
and
the
U.
K.
Committee
on
Toxicity
in
Chemicals
in
Food
have
all
picked
levels
at
which
MeHg
in
the
body
is
not
harmful,
and
the
threshold
levels
set
by
each
organization
are
well
above
the
EPA's
recommended
level.
In
other
words,
the
EPA
has
not
only
picked
an
unnecessarily
low
level
of
human
exposure
compared
to
five
other
U.
S.
and
international
organizations,
but
it
now
appears
that
the
agency
is
suggesting
that
there
is
no
dose
of
MeHg
that
is
safe.
If
that
is
what
the
EPA
is
now
concluding,
it
is
not
only
contrary
to
all
existing
scientific
evidence,
including
the
on­
going
analysis
of
the
value
of
selenium
in
countering
MeHg
exposure,
it
constitutes
a
tragic
application
of
the
easily­
abused
precautionary
principle.
Moreover,
how
is
the
EPA
proposing
to
measure
the
positive
health
impact
of
the
Hg
reductions
it
is
proposing?
If
the
EPA
discovers
that
there
is
no
measurable
positive
impact
from
its
new
rules,
would
the
EPA
then
rescind
its
regulations?

Only
by
declaring
that
there
is
no
safe
dose
of
MeHg
can
the
EPA
justify
reducing
emissions
from
U.
S.
power
plants.
This
is
because
there
is
ample
evidence
to
show
that
elemental
9­
239
Hg
emissions
from
U.
S.
power
plants
are
a
very
small
percentage
of
the
elemental
Hg
falling
onto
U.
S.
soil
and
waters.
Further,
there
is
ample
evidence,
submitted
in
detailed
comments
by
the
Center
for
Science
and
Public
Policy
and
others
to
this
NODA,
that
MeHg
levels
in
fish
and
humans
who
eat
them
have
remained
constant
since
before
the
industrial
revolution
and
subsequent
abundant
coal
use.
In
defending
its
position
that
reducing
Hg
emissions
from
power
plants
will
result
in
lower
MeHg
levels
in
fish,
the
EPA
has
given
some
weight
to
the
Florida
Mercury
Report
of
Nov.
6,
2002,
regarding
MeHg
changes
in
fish
in
the
Everglades
during
the
1990'
s
after
Hg
emission
controls
were
placed
on
waste
incinerators
in
the
area.
However,
the
assumptions
of
this
study
have
been
challenged.
(
See
"
A
Framework
for
Assessing
the
Cost­
Effectiveness
of
Electric
Power
Sector
Mercury
Control
Policies",
PERI,
May
2003.
[
In
a
press
release
issued
on
November
13,
2003,
PERI
observed
that
the
Everglades
study
is
flawed
in
several
material
ways,
including
by
not
recognizing
substantial
differences
between
incinerator
and
power
plant
emissions.)

If
the
EPA
determines
that
there
is
no
safe
Hg
level,
then
the
agency
must
either
order
a
ban
on
all
fish
or
eliminate
all
sources
 
natural
and
anthropogenic
 
of
elemental
Hg
into
the
environment.
Of
course,
it
is
impossible
to
eliminate
Hg
that
is
transported
in
the
air
from
Asia,
that
naturally
exists
in
the
soil
and
oceans,
and
that
is
emitted
from
forest
fires
and
volcanoes.
Merely
regulating
one
very
small
part
of
the
Hg
cycle
U.
S.
power
plants
 
would
do
little
if
anything
to
protect
human
health
from
exposure
to
MeHg
from
fish.
Accordingly,
a
ban
on
eating
fish
would
be
the
only
logical
outcome
of
a
policy
driven
by
a
belief
that
there
is
no
safe
Hg
level.

The
EPA
has
an
opportunity
to
correct
the
health­
science
record
before
the
agency
puts
its
full
reputation
as
the
protector
of
public
health
behind
staff
opinions
that
are
now
based
on
refuted,
discredited,
decade­
old
studies,
including
the
Faroe
Island
study.
It
is
now
clear
that
the
Faroe
Island
study
was
discredited
after
the
original
EPA
analysis
and
after
the
National
Research
Council
study
of
2000,
both
of
which
the
EPA
is
currently
relying
on
to
justify
its
proposed
reference
dose.

The
commenter
either
supported
the
fishing
industry
or
were
in
the
fish
processing
industry.
These
companies
are
severely
affected
by
any
scare
mongering
that
frightens
Americans
away
from
eating
fish
as
part
of
their
diet.
For
a
detailed
analysis
of
the
net
harm
of
scaring
people
away
from
eating
fish,
including
the
loss
of
net
pregnancy
and
net
cardiovascular
benefits,
see
the
comments
being
submitted
on
this
NODA
by
the
Center
for
Science
and
Public
Policy.
The
Center
for
Science
and
Public
Policy
also
provides
analysis
of
the
deficiencies
and
failings
of
several
studies
that
find
negative
cardiovascular
effects
from
consuming
MeHg
from
fish.
The
EPA
also
should
recognize
that
The
Institute
of
Medicine
is
going
to
do
a
two­
year
study
of
the
benefits
of
fish
consumption,
which
could
embarrass
any
EPA
actions
that
have
resulted
in
driving
people
away
from
fish
consumption
for
no
measurable
health
benefit.

The
commenter
added
that
any
EPA
analysis
must
consider
other
risks
to
public
health
that
occur
when
electricity
and
natural
gas
prices
skyrocket
as
a
consequence
of
excessive
EPA
regulation
of
coal­
fired
electric
generation.
Clearly,
additional
costs
on
manufactures
will
continue
to
erode
the
manufacturing
employment
base
in
this
country
as
they
struggle
to
compete
9­
240
with
low­
cost
foreign
manufacturers.
However,
not
only
are
manufacturing
jobs
at
risk
 
and
the
higher
compensation,
better
health
care
and
pension
plans
that
manufacturing
workers
enjoy
compared
to
the
rest
of
the
economy
 
but
so
are
risks
associated
with
a
lower
tax
bases
that
is
the
result
of
having
a
weak
manufacturing
sector,
which
would
lead
to
lower
public
services,
including
health
clinics.
A
weak
manufacturing
sector
and
high
electricity
costs
will
sap
the
investment
markets
upon
which
millions
of
current
and
potential
retirees
depend.
Finally,
dramatically
increasing
the
costs
of
electricity
and
natural
gas
prices
paid
by
homeowners
must
be
recognized
as
harming
many
economically
disadvantaged
people,
who
have
the
least
capacity
to
absorb
these
additional
costs.

Thus,
the
EPA's
actions
to
regulate
Hg
emissions
have
the
significant
­
and
so
far
unaccounted
for
by
the
EPA
­
potential
for
harming
public
health
that
must
be
weighed
against
the
minuscule
benefits
of
regulating
elemental
Hg
emissions
from
U.
S.
coal­
based
power
plants.

Response:

Please
see
the
RIA
as
well
as
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112
Notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.

Comment:

One
commenter
(
OAR­
2002­
0056­
5556)
noted
that
the
EPA
need
not
limit
its
benefits
analysis
to
any
single
quantifiable
health
benefit
but
rather
should
consider
all
pertinent
anticipated
benefits
to
human
health.
It
may
be
especially
important
to
include
a
discussion
on
the
benefits
to
adult
cardiovascular
health
as
this
effect
has
been
correlated
with
MeHg
exposures
at
or
below
levels
associated
with
neurodevelopmental
effects
(
Toxicological
Effects
of
Methylmercury,
National
Academy
of
Sciences,
2003).
This
commenter
stated
that
it
is
also
important
to
include
any
expected
improvements
in
water
quality
and
subsequent
reductions
of
MeHg
in
fish
tissue,
realizing
that
a
reduction
in
Hg
emissions
of
at
least
75
percent
may
be
required
before
measurable
environmental
impacts
can
be
detected.

Response:

EPA
recognizes
that
research
is
ongoing
in
a
number
of
areas
related
to
both
mortality
and
morbidity
in
relation
to
methylmercury
exposure.
However,
at
the
time
of
this
regulation,
existing
peer­
reviewed
evidence
was
not
considered
sufficiently
conclusive
to
include
these
additional
health
endpoints
in
the
primary
benefits
analysis
and
EPA
has
focused
on
reductions
in
IQ
resulting
from
prenatal
exposure
in
estimating
health­
related
benefits.
See
Appendix
B
for
a
detailed
discussion
of
the
current
status
of
research
involving
the
mortality
endpoint
for
9­
241
methylmercury
exposure.

Comment:

One
commenter
(
OAR­
2002­
0056­
5471)
referenced
comments
on
the
Proposed
Rule
that
supports
the
control
of
Hg
from
coal­
fired
EUSGUs
through
a
cap­
and­
trade
program.
However,
for
the
ultimate
rule
to
establish
a
regulatory
program
that
reflects
a
reasonable
estimate
of
benefits
from
Hg
emission
reductions,
this
commenter
believes
that
EPA
must
assign
to
EUSGU
Hg
emissions
only
those
health
risks
that
can
be
traced
to
those
emissions.

In
the
preamble
to
the
Proposed
Rule,
the
Agency
claimed
that
substantial
benefits
would
result
from
the
proposed
CAMR.
But
the
claimed
benefits
are
based
almost
entirely
on
the
value
of
estimated
health
benefits
from
the
decline
in
ambient
PM
2.5
caused
by
the
SO
2
and
NOx
reductions
resulting
from
the
control
measures
required
to
reduce
Hg
emissions
(
primarily
SO
2
scrubbers
and
selective
catalytic
reduction
(
SCR)).
Because
the
Proposed
Rule
relied
almost
exclusively
on
these
co­
benefits
of
the
proposed
regulatory
control
of
Hg,
this
commenter
stated
that
no
health
benefits
were
directly
associated
with
reductions
in
Hg
emissions.
The
Agency's
intention
in
the
NODA,
at
least
in
part,
appears
to
be
to
develop
a
methodology
to
better
quantify
benefits
attributable
to
the
proposed
CAMR
by
isolating
the
benefits
of
Hg
emissions
reductions
from
those
benefits
associated
with
SO
2
and
NOx
emission
reductions.
While
this
commenter
supports
the
Agency's
undertaking
of
the
additional
analysis,
EPA's
proposed
approach
to
assessing
the
benefits
of
Hg
emissions
reductions
creates
a
danger
of
overestimation
of
those
benefits.

Response:

EPA
has
developed
a
benefits
analysis
methodology
for
this
RIA
that
is
designed
to
provide
unbiased
estimates
of
health­
related
benefits
resulting
from
regulatory
options
considered
under
CAMR.
In
keeping
with
convention,
efforts
have
been
made
to
use
peerreviewed
methods
and
data
sets
when
available
and
to
avoid
introducing
conservative
assumptions
at
all
stages
in
the
benefits
modeling
process.
EPA's
emphasis
on
representativeness
has
meant
that
a
number
of
health
endpoints,
that
may
ultimately
be
supported
by
research
findings
(
e.
g.,
cardiovascular­
related
mortality
and
immunologic­
related
morbidity),
have
been
excluded
from
the
primary
analysis
in
order
to
include
only
those
endpoints
in
the
formal
benefits
analysis
for
which
there
is
strong
peer­
reviewed
support.
For
additional
details
on
the
modeling
framework
including
all
key
assumptions
and
input
datasets,
please
review
Chapter
10
in
the
RIA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5471)
noted
that
in
the
NODA,
EPA
requests
general
comments
on
analytical
approaches
to
translating
estimates
of
reductions
in
Hg
emissions
from
EUSGUs
into
approximate
health
outcomes
in
humans.
It
has
been
suggested
that
one
guide
for
this
analysis
is
the
Agency's
regulation
of
lead.
In
the
late
1970s,
EPA
initiated
a
successful
9­
242
program
designed
to
eliminate
all
lead
emissions
into
the
environment
primarily
through
the
phase­
out
of
leaded
gasoline.
Since
airborne
lead
emissions
are
linked
to
blood
lead
levels
in
children
and
related
neurological
impacts,
it
may
appear
reasonable
to
utilize
the
lead
elimination
model
for
dealing
with
Hg.

However,
this
commenter
believes
there
are
significant
differences
between
the
nature
of
lead
emissions
and
EUSGU
Hg
emissions
and
the
health
benefits
reasonably
associated
with
reducing
those
emissions.
If
these
differences
are
not
taken
into
account,
the
commenter
believes
that
blindly
making
assumptions
for
Hg
emissions
reductions
based
on
the
Agency's
experience
with
lead
will
cause
EPA
to
overestimate
the
benefits
of
Hg
emissions
reductions.
First,
virtually
all
airborne
lead
is
attributed
to
anthropogenic
sources
while
a
large
percentage
of
airborne
Hg
(
greater
than
50
percent)
is
due
to
natural
sources.
Thus,
while
the
Agency
acted
reasonably
in
targeting
all
lead
emissions,
it
is
impossible
to
eliminate
all
airborne
Hg
emissions.
Second,
lead
emissions
and
ambient
lead
concentrations
are
primarily
associated
with
urban
areas
while
Hg
emissions
and
ambient
Hg
concentration
are
widespread
on
a
global
scale.
Third,
while
there
appears
to
be
no
lower
limit
for
neurological
impacts
for
lead
blood
levels,
Hg
blood
levels
have
a
clear
threshold
below
which
there
are
no
neurological
impacts.
Fourth,
while
neurological
impacts
were
clearly
shown
at
blood
lead
levels
present
in
children
in
U.
S.
urban
areas
in
the
1970s,
no
such
neurological
impacts
have
been
noted
or
documented
at
Hg
blood
levels
currently
found
in
child­
bearing
age
women
or
children
in
the
U.
S.

Comment:

One
commenter
(
OAR­
2002­
0056­
5471)
noted
that
in
explaining
Step
5
of
its
revised
benefits
analysis,
EPA
seeks
comment
on
its
proposed
use
of
three
studies,
including
a
study
from
the
Faroe
Islands,
to
estimate
the
relationship
between
reductions
in
MeHg
exposure
and
improvements
in
health
and
its
proposed
use
of
intelligence
quotient
(
IQ)
decrements
associated
with
prenatal
MeHg
exposure
to
quantify
and
value
the
health
benefits
of
reduced
exposure
to
MeHg.

EPA
has
selected
a
reference
dose
(
RID)
for
Hg
in
maternal
blood
(
5.8
ppb)
that
serves
as
a
de­
facto
threshold.
This
number,
which
is
10
times
below
the
threshold
number
developed
from
the
Faroe
Islands
study
and
14
times
lower
than
the
World
Health
Organization's
level
of
concern,
is
very
conservative.
This
commenter
believes
that
if
an
unrealistically
low
threshold
for
Hg
blood
levels
were
used
to
estimate
benefits,
reductions
in
blood
levels
between
the
true
threshold
and
the
unrealistically
low
one
would
create
the
appearance
of
a
benefit
where
there
is
none.

The
commenter
stated
that
the
danger
of
using
the
RID
as
the
benchmark
for
assuming
benefits
is
revealed
by
EPA's
proposal
to
develop
a
relationship
between
Hg
emissions
and
general
population
IQ.
There
is
no
evidence
of
IQ
impact
at
blood
Hg
levels
greater
than
the
RID
but
below
the
Faroe
Island
threshold
level.
Yet,
if
this
relationship
were
then
coupled
with
an
imputed
value
for
increased
IQ
for
the
general
population,
large
estimated
benefits
could
be
generated
that
would
not
exist.
Likewise,
if
EPA's
proposed
assumption
of
a
linear
response
9­
243
between
blood
Hg
levels
and
IQ
would
lead
to
an
imputed
benefit
for
reducing
blood
Hg
below
the
threshold
level,
the
Agency
would
be
creating
benefits
that
do
not
exist.

While
the
commenter
does
not
support
all
the
findings
of
the
Faroe
Islands
study,
the
study
provides
a
minimum
threshold
for
blood
Hg
levels.
This
commenter
recommends
that
the
Agency
use
at
least
the
threshold
level
established
in
that
study
(
if
not
a
higher
one,
such
as
the
WHO
level
of
concern),
and
not
the
RID,
as
the
benchmark
for
measuring
health
benefits.

Response:

Please
see
Chapters
10
and
11
of
the
RIA
for
a
discussion
of
the
CAMR
benefits.

Comment:

One
commenter
(
OAR­
2002­
0056­
5476)
commented
on
Step
5
of
the
NODA
addressing
cost/
benefit
analyses
and
how
reduction
will
improve
human
health.
The
commenter
finds
that
EPA's
benefits
analysis
does
nothing
to
address
the
importance
of
fishing
as
a
cultural
practice.
There
is
no
way
to
place
a
dollar
amount
on
the
benefit
to
spiritual
well­
being
as
a
result
of
practicing
a
centuries­
old
tradition
and
passing
it
on
to
our
children.
In
a
more
concrete
measurement,
EPA
does
nothing
to
address
replacing
a
subsistence
food
source
that
provides
a
significant
amount
of
nutrition
for
our
Band
members.
In
making
a
local,
easily
obtainable
food
source
inedible
due
to
poisoning,
EPA
should
calculate
the
costs
that
will
be
incurred
in
cleaning
up
these
toxins
to
improve
the
health
and
physical
well­
being
of
the
people
and
the
health
of
the
environment
for
today's
and
future
generations.
The
commenter
was
also
unaware
of
any
attempts
EPA
has
made
to
quantify
the
costs
of
the
learning
and
educational
problems
that
exposed
children
may
experience.
For
example,
the
loss
in
lifetime
earnings
resulting
from
retardation
of
mental
aptitude
in
the
generalized
population
as
a
result
of
Hg
poisoning
has
been
estimated
at
$
2.3
billion
per
year.
By
refusing
to
set
adequate
MACT
standards,
EPA
is
shifting
this
economic
burden
onto
the
heads
of
indigenous
people
and
their
communities
as
a
whole.
Another
error
in
the
EPA's
cost/
benefit
analysis
comes
from
the
projection
of
$
15
billion
in
savings
due
to
health­
related
benefits
from
its
proposed
rule
when
forecasted
against
the
do
nothing
option.
These
are
simply
health
benefits
that
accrue
from
EPA's
very
substandard
proposal.
The
commenter
believes
that
if
the
more
stringent
MACT
standard
were
set
in
place,
additional
billions
of
dollars
could
be
saved.

This
commenter
believes
that
EPA
has
also
failed
to
assess
tourism­
related
impacts.
Tourism
in
$
9.8
billion
annually
in
Minnesota
alone.
Of
this
total,
sport
enthusiasts
spend
$
1.58
billion,
or
16
percent.
Locally,
Lake
Mille
Lacs
universally
recognized
as
a
premier
trophy
fishing
lake
and
its
Lake­
related
tourism
adds
an
estimated
$
150
million
into
the
local
economy
annually.
Although
it
is
unknown
to
what
level
fish
advisories
impact
these
number,
fishing
and
tourism
bring
in
income
that
the
State
of
Minnesota
cannot
afford
to
lose.
The
other
Great
Lakes
states
of
Wisconsin,
Michigan,
Illinois,
Indiana,
and
Ohio
face
similar
situations.
Together,
these
States,
along
with
Minnesota,
attract
7.8
million
anglers
annually
who
spend
$
5
billion
in
fishing­
related
dollars.
Although
these
are
not
directly
health­
related
issues,
they
certainly
need
to
be
addressed
9­
244
in
EPA's
economic
considerations.

The
commenter
also
takes
issue
with
the
modeling
performed
in
the
analysis.
The
commenter
does
not
believe
the
science
of
modeling
is
at
a
state
where
it
can
accurately
be
used
for
Hg
due
to
the
lack
of
understanding
about
dry
deposition.
Currently
among
many
ambient
air­
monitoring
personnel,
there
is
a
strong
opinion
that
there
are
too
few
dry
deposition
monitors
in
the
North
American
continent
and
barely
adequate
network
of
wet
deposition
monitors
in
the
eastern
half
of
the
U.
S.,
with
very
little
of
either
monitors
existing
on
Anishinaabewaki
(
Indian
Country)
so
it
is
very
hard
to
say
how
much
wet
or
dry
deposition
of
Hg
is
occurring
in
these
areas.
Based
on
this
concern,
the
commenter
believes
it
is
not
in
the
Band's
interest
to
propose
a
cap
and
trade
program
relying
on
the
results
of
EPA's
models.
In
turn,
the
commenter
asks
the
EPA
to
uphold
its
Trust
responsibility
obligations
by
erring
on
the
side
of
caution
rather
than
be
wrong
in
such
an
important
matter.
To
account
for
the
lack
of
confidence
in
the
models,
EPA
should
abandon
its
idea
of
cap­
and­
trade
and
cleave
to
a
MACT
standard.

The
commenter
believes
that
the
National
Emissions
Inventories
used
in
EPA's
analysis
probably
underestimated
the
amount
of
Hg
emitted
from
some
sources,
especially
in
the
western
and
central
regions
of
the
U.
S.,
such
as
miscellaneous
product
disposal.
EPA
has
used
the
best
information
it
has
available,
but
it
should
leave
a
margin
of
safety
to
account
for
inaccuracies.

The
commenter
believes
there
is
a
MACT
calculation
problem.
The
EPA
seems
to
have
followed
a
methodology
recommended
by
a
utility
trade
group,
using
a
short­
term
worst­
case
analysis
to
develop
a
long­
term
average
standard.
This
method
used
only
the
2.5
percent
worst
emissions
from
relevant
sources,
ignoring
the
97.5
percent
best
emission
reductions.

The
commenter
would
like
to
reference
the
excellent
comment
letter
by
the
Forest
County
Potawatomi
Community
(
FCPC
)
to
EPA
on
the
Mercury
Utility
Rule
(
US
EPA
Document
ID
No.
OAR­
2002­
0056­
2173,
April
27,
2004).
The
experts
retained
by
the
FCPC
stated
in
attachments
to
that
letter
why
EPA's
proposed
MACT
standards
are
unacceptable
and
why
EPA
improperly
failed
to
consider
alternate
methods
of
removal,
such
as
activated
carbon
injection.
The
commenter
is
unable
to
make
specific
comments
on
these
issues
as
time
is
running
short.
The
commenter
also
believes
that
it
cannot
add
anything
to
the
discussion
that
has
not
already
been
said
in
the
FCPC
letter.

In
studying
Table
1
of
the
Notice
of
Data
Availability,
it
appears
that
it
really
is
not
much
more
expensive
to
control
emissions
of
7.5
tons
per
year
rather
than
of
15
tons
per
year.
A
two­
phase
cap
of
15
tons
is
projected
to
cost
$
3.3
billion
by
2010
and
$
6.7
billion
by
2020.
But
a
two­
phase
cap
of
7.5
tons
is
expected
to
cost
$
4.6
billion
by
2010
and
$
7.1
billion
by
2020.
The
difference
by
2020
is
only
6
percent!
Even
with
all
of
EPA's
incomplete
assumptions
that
lead
to
faulty
calculations
and
failure
to
carry
out
a
proper
MACT
determination,
it
only
makes
a
6
percent
difference
in
cost.

Though
most
of
the
Band
members
are
oblivious
to
any
of
EPA's
calculations
or
rule­
making,
among
those
of
us
in
Tribal
Government
who
are
entrusted
and
statutally
obligated
9­
245
to
protect
the
health
of
our
Band
members
and
the
health
of
the
natural
resources
available
to
the
Band
members,
or
to
our
Band
members
who
actively
seek
to
information,
it
would
be
hard
to
over­
state
the
level
of
utter
disbelief
expressed
across
Anishinaabewaki
over
the
way
EPA
has
handled
this
rule­
making.

Response:

EPA
has
used
a
cost­
of­
illness
function
based
on
lost
earnings
resulting
from
methylmercury
exposure
as
the
basis
for
its
primary
benefits
estimate
in
the
RIA
(
i.
e.,
prenatal
methylmercury
exposure
through
maternal
consumption
producing
IQ
decrements
in
children
which
translate
into
lost
earnings
later
in
life).
This
valuation
function,
which
is
based
on
the
approach
used
in
past
EPA
regulations
concerning
lead
exposure,
also
considers
the
impact
of
lowered
IQ
on
years
of
education
achieved.
EPA
acknowledges
that
because
this
function
is
based
on
cost­
of­
illness
and
not
willingness­
to­
pay
(
WTP),
it
likely
represents
a
lower
bound
for
valuation
of
the
IQ
decrements
and
that
a
more
comprehensive
WTP­
based
function
would
capture
other
factors
such
as
those
listed
by
the
commentor
above.
Note,
EPA
did
not
use
a
WTP­
based
function
in
the
benefits
analysis
because
peer­
reviewed
literature
does
not
support
derivation
of
such
a
function
at
this
time.

Comment:

One
commenter
(
OAR­
2002­
0056­
5517)
notes
that
the
NODA
fails
to
provide
a
scientifically
sound
reason
as
to
why
EPA
adds
a
factor­
of­
ten
safety
factor
in
calculating
what
is
an
acceptable
daily
intake
of
MeHg
from
eating
fish.
Adding
such
a
safety
factor
is
usually
done
to
account
for
how
sensitive
populations,
such
as
children,
who
are
believed
to
be
more
sensitive
to
MeHg
than
adults,
differ
in
response
to
the
general
population.

This
commenter
points
out
that
the
reason
the
additional
safety
factor,
as
used
by
EPA,
is
questionable
is
that
the
available
studies
of
the
health
effects
of
MeHg
exposures
focus
both
on
healthy
and
sensitive
subpopulations
inclusively,
thus
their
particular
susceptibilities
are
already
accounted
for,
obviating
the
need
for
any
added
safety
factor.
EPA
has
provided
no
information
in
this
NODA
that
would
justify
the
inclusion
of
the
factor­
of­
ten
safety
factor
used
by
the
agency;
as
such
its
use
is
clearly
arbitrary
and
capricious.
Moreover,
there
is
no
explicit
statutory
authority
in
the
Clean
Air
Act
that
mandates
the
use
of
such
a
safety
factor.

In
their
comments
to
EPA
concerning
the
agency's
proposed
rule
to
control
emissions
of
Hg
from
coal­
fired
power
plants,
other
national
trade
associations
have
also
addressed
the
questionable
safety
factor
used
by
EPA
in
establishing
what
is
an
acceptable
daily
intake
of
MeHg
from
eating
fish.
These
organizations
also
find
that
the
use
of
the
factor­
of­
ten
safety
factor
is
not
justified.
The
commenter
believes
that
its
observations
have
merit
and
must
be
given
careful
consideration.

Response:
9­
246
In
deriving
the
reference
dose
for
methylmercury,
EPA
relied
on
an
integrated
analysis
involving
three
studies.
These
longitudinal,
developmental
studies
were
conducted
in
the
Seychelles
Islands,
the
Faroe
Islands,
and
New
Zealand.
The
Seychelles
study
yielded
scant
evidence
of
impairment
related
to
in
utero
methylmercury
exposure,
whereas
the
other
two
studies
found
dose­
related
effects
on
a
number
of
neuropsychological
endpoints.
In
the
assessment
developed
for
the
RfD,
emphasis
is
placed
on
the
results
of
the
Faroe
Islands
study,
the
larger
of
the
two
studies
that
identified
methylmercury­
related
developmental
neurotoxicity.
Supporting
evidence
from
the
New
Zealand
study
provides
assurance
that
choosing
this
focus
is
the
appropriate
strategy
for
protecting
public
health.
Conclusions
from
the
National
Research
Council
review
of
methylmercury
support
this
use
of
the
Faroes
Island
study
and
disagree
with
the
suggestion
of
a
role
for
PCBs
in
the
neurological
effects
observed
(
NRC.
2000.
Toxicological
Effects
of
Methylmercury.
National
Academy
Press.),
saying
that
"
The
committee
concludes
that
there
do
not
appear
to
be
any
serious
flaws
in
the
design
and
conduct
of
the
Seychelles
Islands,
Faroe
Islands,
and
New
Zealand
studies
that
would
preclude
their
use
in
a
risk
assessment."

The
Agency's
derivation
of
the
RfD
also
followed
the
National
Research
Council
recommendation
for
an
overall
composite
uncertainty
factor
of
no
less
than
10.

In
summary,
the
Agency's
overall
confidence
in
this
RfD
assessment
is
high.
Three
high­
quality
epidemiological
studies
published
since
the
last
derivation
of
the
oral
RfD
in
1995,
have
been
included
in
the
analysis.
Two
of
the
studies
(
Faroe
Islands,
New
Zealand)
reported
effects
on
a
number
of
neuropsychological
endpoints,
whereas
the
third
(
Seychelles
Islands)
reported
no
effects
related
to
in
utero
exposure
to
methylmercury.
Benchmark
dose
analysis
of
a
number
of
endpoints
from
both
the
New
Zealand
and
Faroe
Islands
study
converged
on
an
RfD
of
0.1
µ
g/
kg­
day,
as
did
the
integrative
analysis
combining
all
three
studies.
Although
there
was
coexposure
to
PCBs
in
the
Faroe
Islands
study,
statistical
analysis
indicated
that
the
effects
of
PCBs
and
methylmercury
were
independent.
Moreover,
benchmark
dose
analysis
of
the
endpoints
that
were
significantly
associated
with
methylmercury
yielded
RfDs
that
were
approximately
the
same
when
corrected
for
PCBs.
The
same
was
true
when
the
analysis
was
or
based
on
the
subset
of
the
cohort
in
the
lowest
tertile
with
respect
to
PCB
levels,
as
compared
with
the
full
cohort.
These
findings
provide
further
evidence
that
the
identified
effects
are
in
fact
the
result
of
methylmercury
exposure.

Comment:

One
commenter
(
OAR­
2002­
0056­
5517)
reports
that
it
recently
received
an
e­
mail
communication
from
Professor
Gary
Myers
of
Rochester
University
who
leads
the
child
development
study
of
prenatal
MeHg
exposure
from
ocean
fish
consumption
in
the
Seychelles
Islands.
His
e­
mail
message
concerns
EPA's
stated
intention
outlined
in
the
NODA
to
analyze
whether
data
from
the
various
major
MeHg
exposure­
effects
studies,
such
as
those
of
the
Seychelles
and
Faroe
Islanders,
can
be
integrated.
Dr.
Myers
observes,
"
I
do
not
think
there
is
any
way
to
compare
the
two
[
Seychelles
and
Faroe
Island]
studies
regarding
exposure.
They
are
9­
247
simply
different."
In
view
of
this
communication,
the
commenter
suggests
that
EPA
confer
further
with
Dr.
Myers
on
this
matter
to
clarify
the
specifics
of
his
expressed
concern.

Response:

Please
see
Chapter
9
of
the
RIA
for
a
discussion
of
the
derivation
of
a
dose­
response
function
using
both
the
Seychelles
and
Faroes
data.

Comment:

One
commenter
(
OAR­
2002­
0056­
5447)
stated
that
EPA's
NODA
poses
a
number
of
questions
related
to
modeling
runs
that
have
been
performed
to
simulate
electric
system
operation
and
decision
making
to
predict
how
utilities
would
comply
with
EPA's
two
proposed
regulatory
options.
69
Fed.
Reg.
69866­
69872.
EPA
states
that
modeling
predictions
of
how
electric
generation
would
shift
in
response
to
the
Hg
rule
is
relevant
because
EPA
is
required
to
examine
"
cost,
nonair
quality
health
and
environmental
impacts,
and
energy
requirements"
under
both
Clean
Air
Act
(
CAA)
§
111
and
112(
d).
69
Fed.
Reg.
69866
The
commenter
also
noted
that
EPA
also
requests
comments
on
its
proposed
revisions
to
its
benefits
assessment
under
EO12866.
69
Fed.
Reg.
69,872.
EO12866
states
that
"
agencies
should
assess
all
costs
and
benefits
of
available
regulatory
alternatives."
EO12866,
Section
1.
Costs
and
benefits
must
be
considered
on
a
"
net"
basis,
meaning
both
positive
and
negative
public
health
effects
of
a
regulation
must
be
considered
together.
Id.
The
fact
that
it
is
difficult
to
quantify
certain
costs
and
benefits
does
not
mean
these
costs
and
benefits
may
be
ignored.
Under
EO12866,
"[
c]
osts
and
benefits
shall
be
understood
to
include
both
quantifiable
measures
(
to
the
fullest
extent
that
these
can
be
usefully
estimated)
and
qualitative
measures
of
costs
and
benefits
that
are
difficult
to
quantify,
but
nevertheless
essential
to
consider."
Id.
EPA's
analysis
of
the
"
cost
[
and]
nonair
quality
health
and
environmental
impacts"
and
its
EO12866
benefits
assessment
are
defective
because
they
fail
to
consider
significant
societal
costs
associated
with
unduly­
stringent
Hg
regulations.
Indeed,
a
number
of
outcomes
forecast
by
the
modeling
performed
in
this
docket
(
e.
g.,
plants
shutting
down)
would
cause
significant
economic
and
human
health
impacts
that
are
overlooked
in
EPA's
analysis.
If
coal
plants
are
modeled
to
shut
down
(
e.
g.,
Cinergy's
model
of
"
Stringent
MACT
Plus
CAIR,"
69
Fed.
Reg.
69868,
col.
3)
or
reduce
capacity
factors,
these
shut
downs
will
cause
the
economic
impacts
of
increased
gas
and
electricity
prices.
These
higher
prices
will,
in
turn,
cause
higher
costs
in
the
manufacturing
sector,
loss
of
jobs,
and
the
loss
of
energy
security.
According
to
a
recent
study,
"
replacement
of
U.
S.
coal­
fueled
power
could
impact
household
income
by
an
estimated
$
125­$
225
billion
in
2010,"

In
addition,
forcing
a
shift
in
the
nation's
fuel
supply
from
coal
to
natural
gas
will
result
in
significant
increased
risks
to
public
health.
Depending
on
the
models
used,
removing
coal
from
America's
energy
mix
would
directly
result
in
anywhere
from
7,000­
51,000
premature
adult
deaths
per
year.
However,
severe
mortality
impacts
would
result
even
if
EPA's
regulations
do
not
cause
a
complete
shut
down
of
coal­
fueled
electricity,
but
only
cause
some
shift
from
low­
cost
coal
generation
to
higher
priced
gas
generation.
One
model
shows
that
an
aggregate
9­
248
reduction
in
household
income
of
$
8.9
million
induces
one
additional
adult
death.
These
deaths
would
fall
disproportionately
on
lower­
income
households.

Modeling
outcomes
that
predict
some
coal­
fueled
units
will
be
shut
down
or
run
at
decreased
capacity
must
incorporate
all
potential
impacts
of
such
shut­
downs
or
decreases
in
capacity
when
assessing
the
costs
of
the
regulation.
At
this
point,
EPA's
forecast
modeling
and
benefit
analysis
does
not
consider
the
societal
impacts
of
regulations
that
would
cause
power
plants
to
shut
down
or
run
at
decreased
capacity.
Until
such
analysis
is
provided,
EPA
has
not
met
its
obligation
under
EO12866
to
assess
all
the
costs
and
benefits
of
its
Hg
regulation
and
to
do
so
on
a
net
basis.
For
the
same
reason,
EPA
will
have
failed
to
fully
assess
the
"
cost,
nonair
quality
health
and
environmental
impacts"
of
the
regulation
under
CAA
§
111
and
112(
d).

Response:

The
comment
raises
issues
under
the
general
broad
issue
of
correctly
differentiating
between
social
costs
and
economic
impacts.
It
is
critical
that
proper
analysis
not
violate
economic
theory
and
the
principles
of
benefit­
cost
analysis
in
doing
so.
The
commentor
suggests
EPA
should
consider
the
following
when
calculating
full
societal
costs:

(
1)
potential
shut
down
of
or
decreased
capacity
in
EGUs
(
2)
Higher
energy
costs
(
3)
Loss
of
jobs
(
4)
Loss
of
income
(
5)
Loss
of
energy
security
We
address
each
of
these
separately.

(
1)
Potential
shut
down
or
decreased
capacity
in
EGUs.
In
fact
the
IPM
model
used
by
EPA
to
estimate
costs
and
other
impacts,
does
provide
an
estimate
of
EGU
shutdowns
and
decreased
capacity,
if
relevant.
The
IPM
model
estimates
the
costs
of
meeting
the
U.
S.
demand
for
electricity.
To
the
extent
that
some
EGUs
shutdown,
the
model
must
replace
that
lost
capacity
with
other
capacity.
The
cost
of
replacing
this
lost
capacity
is
estimated
by
IPM.
Hence,
we
want
to
be
clear
that
the
cost
of
plant
shut
downs
(
in
the
form
of
higher
electricity
prices)
is
calculated
and
is
part
of
our
cost
estimates
we
routinely
calculate.

(
2)
Higher
energy
costs.
It
is
true
that
pollution
control
requirements
can
lead
to
higher
energy
prices.
The
IPM
model
does
provide
estimates
of
higher
energy
prices
as
a
result
of
the
regulation.

(
3)
Loss
of
jobs.
The
commentor
argues
that
the
increased
cost
of
electricity
will
lead
to
loss
of
jobs.
It
is
true
that
higher
electricity
prices
can
ripple
through
the
economy
and
disrupt
particular
industries.
However,
to
a
first
approximation,
the
increased
spending
for
pollution
control
equipment
creates
the
same
number
of
jobs
as
the
loss
in
jobs
from
higher
electricity
prices.
Hence,
we
generally
consider
job
loss
to
be
serious
economic
impact,
worthy
of
9­
249
consideration,
but
it
is
not,
in
general,
considered
to
be
a
"
net"
cost
of
a
regulation.
In
fact,
job
creation
by
a
regulation
is
one
component
of
the
costs.
WOrkers
who
make
pollution
control
equipment
must
be
paid.
This
is
part
of
the
cost
of
buying
pollution
control
equipment.

There
is,
however,
one
mechanism
that
can
lead
to
reduced
labor
hours
in
the
economy
that
can
be
a
cost.
In
the
1990'
s
and
beyond,
economists
have
identified
and
investigated
the
so­
called
tax
interaction
effect.
The
problem
arises
because
we
the
economy
already
taxes
labor
services
a
great
deal.
These
labor
taxes
tend
to
generate
too
little
labor
being
provided
to
the
economy.
Any
regulation
that
gives
rise
to
higher
prices,
can
further
depress
the
real
wage.
In
doing
so,
workers
provide
even
less
labor
services
to
the
economy.
While
this
is
conceptually
understood
by
economic
modelers,
the
empirical
estimates
of
this
effect
vary
widely.
Further,
the
benefits
of
environmental
improvement
tend
to
raise
the
productivity
of
the
American
worker.
Reduced
mercury,
for
example,
will
raise
IQ
levels
in
the
economy.
As
workers
get
smarter,
productivity
increases.
Hence,
these
type
of
interaction
effects
can
affect
both
the
costs
and
benefits.

(
4)
Loss
of
income
­­
as
in
the
case
of
jobs,
some
workers
will
find
themselves
with
higher
income
and
some
with
lower
income.
In
general,
job
losses
(
or
gains)
are
not
counted
as
social
costs
of
the
regulation.

(
5)
Loss
of
energy
security.
The
IPM
model
does
give
estimates
of
the
source
fuels
for
the
production
of
electricity.
We
will
then
be
able
to
estimate
whether
imports
of
oil
or
natural
gas
(
or
other
forms
of
energy)
will
go
up
or
down
as
a
result
of
this
regulation.

Comment:

One
commenter
(
OAR­
2002­
0056­
5458)
believed
the
benefits
analysis
must
be
focused
on
the
neurodevelopmental
health
of
children.
In
the
benefit
analysis
referenced
in
the
proposal
and
identified
in
the
NODA,
IQ
reduction
was
chosen
as
the
health
endpoint
to
quantify
the
benefits
of
reducing
MeHg
exposure
in
children.
The
commenter
is
concerned
about
the
use
of
IQ
as
the
endpoint
for
benefits
quantification
across
the
three
major
epidemiological
studies
used
to
develop
the
MeHg
reference
dose
(
RID)
because
IQ
was
only
directly
measured
in
the
New
Zealand
study.
Based
upon
notes
from
the
Mercury
Neurotoxicity
Workshop,
the
selection
of
IQ
as
the
neurological
endpoint
for
quantification
seems
to
be
based
almost
entirely
on
the
fact
that
decrements
in
IQ
can
be
monetized.
The
commenter
will
reserve
its
comments
on
this
aspect
of
the
benefits
analysis
until
it
is
available
for
public
review
and
comment.

Response:

Please
see
Chapter
9
of
the
RIA
for
a
discussion
of
the
derivation
of
the
dose­
response
curve
and
Chaters
10
and
11
for
a
discussion
of
the
monetized
benefits.

Comment:

One
commenter
(
OAR­
2002­
0056­
5488)
said
that
to
date,
the
EPA
has
not
assessed
the
9­
250
public
health
benefits
from
reduced
Hg
exposure
to
the
population,
instead
relying
on
analyses
of
public
health
co­
benefits
resulting
from
reduced
exposure
to
criteria
air
pollutants.
The
NODA
expresses
the
agency's
intent
to
conduct
analyses
of
the
benefits
resulting
from
avoidance
of
IQ
reduction
in
children,
but
it
does
not
specify
the
range
of
regulatory
options
to
be
considered.
Within
the
NODA,
the
only
two
scenarios
mentioned
are
the
base
case
and
the
reductions
afforded
by
the
proposed
CAMR.
The
commenter
believed
that
such
a
limited
analysis
is
entirely
insufficient
to
justify
the
setting
of
Hg
reduction
levels
on
a
health
basis.
The
commenter
requested
that
the
EPA
analyze
and
compare
the
public
health
benefits
associated
with
Hg
reduction
levels
that
are
more
protective
than
those
proposed
under
the
CAMR
and
more
consistent
with
Hg
reductions
levels
demonstrated
above
to
be
achievable.

In
addition,
just
as
the
agency
relied
on
the
co­
benefits
from
reduction
of
criteria
air
pollutants
in
its
initial
benefit
estimate
of
the
proposed
CAMR,
in
the
revised
benefits
analysis,
co­
benefits
from
any
additional
reduction
of
criteria
air
pollutants
as
well
as
co­
benefits
of
reductions
in
other
toxic
air
pollutants
must
be
added
on
to
the
benefits
from
avoidance
of
IQ
reduction
related
to
reduced
exposure
to
MeHg
in
each
Hg
reduction
scenario
modeled.

The
commenter
agreed
with
the
agency
that
the
avoidance
of
IQ
reduction
is
the
best
studied
and
most
easily
monetized
benefit
of
reduced
MeHg
exposure,
and
this
outcome
should
be
included
in
the
revised
benefits
analysis.
But
other
serious
health
effects
must
also
be
accounted
for
in
EPA's
benefits
analysis.
EPA's
benefits
analysis
must
give
full
consideration
to
the
impacts
on
the
immune
and
cardiovascular
systems
in
addition
to
the
nervous
system.
There
is
compelling
evidence
that
additional
health
benefits
result
from
reduced
population
exposure
to
MeHg
beyond
avoidance
of
IQ
reduction.
The
commenter,
therefore
urged
the
agency
to
include
in
its
analysis
the
cardiovascular
and
immune
system
effects
of
Hg
and
expressly
acknowledge
that
the
actual
health
benefits
are
greater
than
those
estimated
based
on
consideration
of
IQ
effects
(
or
reduced
exposure
to
criteria
air
pollutants)
alone.
In
addition,
the
agency
must
account
for
benefits
from
avoided
neurological
effects
such
as
motor
dysfunction
that
are
not
captured
by
estimates
of
lost
income
from
IQ
reduction.

The
selection
of
an
appropriate
dose
response
model
must
ultimately
depend
on
which
model
best
fits
the
data.
The
combined
data
from
the
Seychelles,
Faroe
Islands,
and
New
Zealand
studies
are
well­
modeled
by
a
linear
dose
response
curve.
The
use
of
a
linear
instead
of
a
threshold
model
is
supported
by
the
EPA
IRIS
database,
which
notes
that
no
threshold
was
detected
for
MeHg
neurotoxicity
in
the
Faroe
Islands
study,
as
well
as
the
National
Research
Council
report
on
MeHg.
Use
of
a
linear
model
will
also
facilitate
the
estimation
of
health
benefits
from
MeHg
reductions
below
the
modest
levels
currently
proposed
in
the
CAMR.
Accordingly,
the
best
available
science
shows
that
a
linear
dose
response
model
should
be
used
to
properly
estimate
the
health
benefits
of
Hg
pollution
control
options.

Given
the
complexity
of
this
type
of
analysis
and
its
application
in
the
regulatory
setting,
the
commenter
requested
that
all
assumptions,
methods
and
uncertainties
in
the
modeling
of
Hg
reduction
benefits
be
clearly
and
publicly
documented
and
thoroughly
peer­
reviewed
by
a
balanced
body
of
outside
experts.
9­
251
Response:

The
RIA
includes
an
assessment,
to
the
extent
possible
given
our
scientific
understanding
of
mercury
and
its
behavior
in
the
environment
and
impacts
on
human
health,
of
the
health
benefits
associated
with
the
proposed
regulatory
options.
Due
to
limitations
in
our
current
understanding
of
these
technical
areas
related
to
mercury
this
benefit
analysis
is
limited
to
the
self­
caught
freshwater
fish
consumption
pathway
and
to
IQ
deficits
in
prenatally­
exposed
infants.
In
keeping
with
precedent
in
evaluating
benefits
of
air
regulations
(
REFERENCE),
cobenefits
(
in
this
case
resulting
from
potential
reductions
in
direct
PM2.5)
are
also
included
in
the
RIA.

EPA
acknowledges
that
emission
control
equipment
used
to
reduce
mercury
emissions
may
reduce
emissions
of
other
pollutants
including
PM
and
associated
HAPs.
While
EPA
has
included
an
analysis
of
potential
cobenefits
associated
with
reductions
in
direct
PM2.5,
limitations
in
our
current
understanding
of
differential
toxicity
prevent
us
from
modeling
health
benefits
from
reduced
exposure
to
HAPs
associated
with
that
PM.
Similarly,
while
EPA
concurs
with
the
National
Academy
of
Sciences,
that
a
variety
of
health
endpoints
may
be
associated
with
methylmercury
exposure
in
addition
to
IQ
(
e.
g.,
immune
system
effects,
cardiovascular
mortality
and
additional
neurodevelopmental
endpoints),
there
is
insufficient
peer­
reviewed
evidence
at
this
time
for
conducting
formal
analysis
of
these
endpoints
for
inclusion
in
the
primary
benefits
estimate.

Comment:

One
commenter
(
OAR­
2002­
0056­
5502)
referenced
MeHg
and
Cardiovascular
Effects.
Evidence
that
exposure
to
MeHg
via
fish
consumption
leads
to
a
high
risk
of
adverse
cardiovascular
events
is
generally
lacking;
published
findings
are
contradictory
and
inconsistent
nature,
and
associations
weak.
Multiple
contributing
factors
for
cardiovascular
health
and
striking
cultural
differences
in
coronary
heart
disease
rates
contribute
to
overall
weakness
in
findings.
It
does
not
appear
that
there
is
"
emerging
evidence"
that
MeHg
has
major
effects
on
cardiovascular
systems,
nor
is
there
good
evidence
for
fish
Hg
diminishing
the
cardio­
protective
effect
of
fish
intake.

IQ
and
Neurobehavioral
Tests.
IQ
neither
meets
requirements
for
a
well­
defined
health
effect
for
MeHg
exposure,
nor
has
it
been
used
as
a
primary
health
endpoint
in
the
children's
MeHg
studies.
Major
barriers
to
conducting
a
meta­
analysis
of
the
Faeroe
Islands,
New
Zealand
and
Seychelles
Islands
studies
are:
the
heterogeneity
of
the
study
designs;
the
neurobehavioral
test
batteries
administered;
the
ages
at
testing;
the
lack
of
a
consistent
pattern
of
significant
results
across
studies
(
most
results
are
non­
significant;
however);
the
differences
in
study
populations;
and
the
differences
in
confounders
measured
and
included
in
the
final
multivariate
models.
These
inconsistencies
and
other
shortcomings
are
major
barriers
to
conducting
a
valid
meta­
analysis
of
the
cohort
studies
to
date.

Use
of
a
Linear
Dose­
Response
Model.
Alternatives
to
the
K=
1
model
need
to
be
9­
252
considered.
Published
analyses
of
the
Seychelles
study
suggest
evidence
for
a
non­
linear
association
for
one
or
two
neurobehavioral
test
endpoints
with
a
threshold
that
is
consistent
with
previous
estimates
from
the
Iraqi
study.
Non­
linear
models
need
to
be
applied
to
New
Zealand
and
Faroes
results
prior
to
making
a
final
determination
of
the
best
model
to
fit
these
data.
Further,
a
linear
dose­
response
model
is
questionable
given
that
the
standard
RID
established
by
EPA
assumes
a
threshold
dose
below
which
there
is
not
likely
to
be
an
appreciable
risk
of
deleterious
effects
during
a
lifetime.

Response:

EPA
does
not
have
access
to
the
study
data
for
the
three
key
studies.
The
only
data
available
to
EPA
are
regression
coefficients
and
other
statistics
that
have
been
published
by
the
study
investigators.
Therefore,
EPA
is
not
able
to
conduct
any
modeling
that
would
examine
alternative
shapes
to
the
dose­
response
relationship,
including
non­
linear
models.
EPA's
analysis
involves
a
statistical
integration
of
linear
dose­
response
functions
that
have
been
reported
by
the
study
investigators.
We
believe
that
use
of
a
linear
function,
in
conjunction
with
using
a
nonthreshold
model,
in
our
analysis
is
well­
justified
by
the
following
considerations:
1)
The
National
Research
Council's
2000
report
on
methylmercury
used
linear
model
results
for
deriving
benchmark
doses,
and
cautioned
against
use
of
supralinear
models;
2)
the
Faroe
Islands
research
team
reported
that
K­
power
models
(
with
the
NRC­
recommended
constraint
of
K
>
1,
i.
e.
with
supralinearity
excluded)
fit
best
with
the
linear
specification,
i.
e.
K=
1;
3)
linear
model
results
are
available
for
IQ
for
all
three
studies,
and
no
non­
linear
model
results
are
available
from
the
three
studies
(
except
for
Faroes
log
model),
and
raw
data
are
not
available
to
us
for
conducting
analysis
of
dose­
response
shape
or
other
issues;
and
4)
the
lowest
exposures
in
the
Faroe
Islands
study
overlap
with
U.
S.
exposure
range,
although
there
is
less
overlap
with
the
other
two
studies.
Nonetheless,
EPA's
Reference
Dose
and
the
analysis
supporting
its
derivation
was
reviewed
positively
by
the
National
Academcy
of
Sciences
and
the
Agency
continues
to
support
its
level
and
the
implications.
We
conclude
that
any
analysis
of
the
IQ
benefits
needs
to
deploy
several
models
­­
with
a
threshold
and
without
to
capture
the
full
range
of
uncertainty.
EPA
acknowledges
that
there
are
complexities,
including
a
variety
of
potential
confounders,
that
must
be
considered
in
relation
to
potential
cardiovascular
mortality
linked
to
methylmercury
exposure.
For
additional
discussion
of
this
endpoint,
see
Appendix
D.

Comment:

One
commenter
(
OAR­
2002­
0056­
5535)
stated
that
MeHg
poisoning
incidents,
particularly
the
well­
known
incident
in
Minamata,
Japan,
have
established
Hg
as
a
neurodevelopmental
toxicant.
Three
prospective
epidemiological
studies,
in
the
Faroe
Islands,
the
Seychelles,
and
New
Zealand,
have
been
singled
out
over
the
past
five
years
for
the
development
of
dose
response
calculations.
The
study
in
the
Faroe
Islands
documented
subtle
deficits
of
several
functional
domains
at
prenatal
MeHg
exposure
levels
previously
thought
to
be
safe.
This
finding
was
in
agreement
with
the
New
Zealand
study,
as
well
as
cross­
sectional
epidemiological
studies
in
French
Guiana
and
the
Amazon
that
also
showed
effects
but
do
not
lend
themselves
to
dose­
response
analysis.
Results
from
the
Seychelles
have
not
been
concordant,
however;
to
date,
9­
253
this
prospective
study
has
not
shown
effects.
In
keeping
with
prevailing
standards
of
public
health
protection,
EPA
and
the
NAS
have
used
the
Faroe
and
New
Zealand
studies
as
the
basis
for
regulatory
decision
making.

The
Faroese
study
recently
has
been
updated
to
include
state
of
the
art
neurological
testing
administered
to
the
cohort
of
children
under
study
as
they
have
matured.
Previously,
in
a
1997
report
on
the
Faroese
population,
researchers
examined
children
at
age
7
and
reported
on
abnormalities
in
CNS­
mediated
functions
(
such
as
achievement
of
developmental
milestones)
and
sensitive
measures
of
neurological
function
(
such
as
evoked
potentials,
visual
and
auditory
acuity,
and
neuropsychological
functions).
The
new
data
cover
subsequent
examinations
of
the
Faroese
children
at
age
14
years;
tests
included
brainstem
auditory
evoked
potentials
(
BAEP's).
The
authors
report
that
the
signal
from
the
acoustic
nerve
to
the
brainstem
was
significantly
delayed
in
a
dose­
related
fashion
with
prenatal
exposure
to
Hg.
Because
they
observed
this
effect
at
both
7
and
14
years,
the
authors
suggested
that
this
effect
of
Hg
on
the
developing
brain
is
irreversible.
This
Hg­
associated
delay
in
transmission
appeared
to
be
parallel
to
the
effects
on
the
child's
cognitive
function.
The
measurement
of
BAEPs
is
an
objective
assessment
that
is
independent
of
confounding
factors,
such
as
age
and
socioeconomic.
Most
concerning,
these
children
had
an
average
exposure
similar
to
the
"
safe"
limit
(
i.
e.,
the
reference
dose)
recommended
by
EPA.

Although
the
mechanism
by
which
MeHg
adversely
affects
the
developing
brain
is
not
completely
understood,
there
are
numerous
ways
that
the
compound
has
been
shown
to
affect
neurons.
It
causes
biochemical
and
structural
changes
in
mitochondria
(
the
energy
producer
in
the
cell),
disrupts
protein
synthesis,
causes
membrane
damage
in
nerve
cells,
and
may
create
free
radicals
that
damage
lipids
and
result
in
neuronal
damage.
Oxidative
damage
may
be
a
factor
in
MeHg
toxicity,
since
concentrations
of
the
repair
enzyme
glutathione
decline
and
then
increase
after
exposure
to
MeHg.
MeHg
also
has
been
shown
to
disrupt
cell
division
and
cell
migration
by
disrupting
structural
microtubular
proteins.
None
of
these
effects
is
likely
to
have
a
clear
threshold
below
which
it
does
not
occur.

Other
Important
Health
Endpoints
Beyond
neurotoxicity,
research
links
Hg
with
a
host
of
other
health
effects.
First,
the
impact
of
Hg
on
overall
growth
and
development
has
been
supported
by
data
published
since
2000.
In
the
Faroese
cohort,
pre­
and
postnatal
MeHg
exposure
was
found
to
be
associated
with
decreased
postnatal
growth,
particularly
before
18
months
of
age.
The
authors
found
that,
"
irrespective
of
duration
of
breast­
feeding,
a
doubling
of
the
Hg
concentration
in
cord
blood
was
associated
with
a
decrease
in
weight
and
height."
Second,
Hg
may
have
immunotoxic
effects.
Hg
induces
autoimmune
disease
in
rodents.
Highly
susceptible
mouse
strains
develop
multiple
autoimmune
manifestations
after
exposure
to
inorganic
Hg,
including
proliferation
of
lymphocytes,
elevated
levels
of
autoantibodies,
overproduction
of
immunoglobulins
(
IgG
and
IgE),
and
circulating
immune
complexes
that
can
clog
the
kidney
and
vasculature.
Now,
a
recent
cross­
sectional
study
provides
evidence
that
a
population
of
Hg­
exposed
adults
living
in
the
Amazon
region
has
an
increased
prevalence
of
elevated
autoantibodies,
indicative
of
autoimmune
dysfunction.
9­
254
Third,
several
studies
have
linked
Hg
exposure
to
cardiovascular
disease.
Although
some
fish
species
contain
beneficial
omega­
3
fatty
acids,
and
fish
is
a
low­
fat
source
of
protein,
recent
studies
raise
the
possibility
that
moderate
Hg
content
in
fish
may
in
fact
diminish
the
cardioprotective
effect
of
fish
intake.
A
2000
study
reported
an
association
between
moderate
hair
Hg
content
and
accelerated
progression
of
arteriosclerosis
in
the
carotid
arteries
leading
to
the
brain
(
determined
by
ultrasonographic
assessment
of
common
carotid
intima­
media
thickness)
in
a
prospective
study
among
1,014
men
aged
42­
60
years
in
Finland.
Hair
Hg
levels
greater
than
2
ppm
(
well
within
the
range
of
the
U.
S.
adult
population)
showed
a
doubling
of
the
risk
of
cardiovascular
mortality.
This
study
was
recently
updated
and
reported
that
Hg
in
hair
above
2
ppm
may
be
a
risk
factor
for
acute
coronary
events
and
cardiovascular
disease,
coronary
heart
disease,
and
all­
cause
mortality
in
middle­
aged
eastern
Finnish
men.

Similarly,
a
study
published
in
the
New
England
Journal
of
Medicine
reported
that
toenail
Hg
level
(
an
indicator
of
total
Hg
exposure)
was
directly
associated
with
the
risk
of
myocardial
infarction.
This
case­
control
study
was
conducted
in
eight
European
countries
and
Israel,
and
studied
684
men
with
a
first
diagnosis
of
myocardial
infarction.
The
authors
report
that
the
Hg
levels
in
the
patients
were
15
percent
higher
than
those
in
controls
(
95
percent
confidence
interval,
5
to
25
percent).
The
risk­
factor­
adjusted
odds
ratio
for
myocardial
infarction
associated
with
the
highest
as
compared
with
the
lowest
quintile
of
Hg
was
2.16,
a
more
than
twofold
increase
in
the
risk.
The
authors
suggest
certain
mechanisms
that
may
contribute
to
this
effect,
including
inactivating
the
protective,
antioxidant
properties
of
the
repair
enzymes
glutathione
or
catalase,
inducing
cell
membrane
damage
by
lipid
peroxidation,
promoting
platelet
aggregability
and
blood
coagulability,
and
affecting
the
inflammatory
response,
among
several
others.

Although
a
third
study
on
cardiovascular
health
was
unable
to
replicate
these
findings,
the
study
population
consisted
largely
of
dentists
who
had
occupational
exposure
to
elemental
Hg.
Since
Hg
exposure
measurements
in
this
study
were
based
on
total
Hg,
the
elemental
Hg
exposure
could
have
confounded
detection
of
a
MeHg
effect.
In
fact,
when
the
dentists
were
removed
from
the
study,
an
association
with
cardiovascular
outcomes
(
albeit
not
statistically
significant,
possibly
due
to
the
smaller
sample
size)
was
seen
with
Hg
exposure.

The
new
data
on
MeHg
indicate
that
neurodevelopmental
effects
are
likely
to
be
permanent
and
to
be
present­
according
to
objective
measures
 
at
Hg
levels
lower
than
previously
reported.
It
is
also
increasingly
clear
that
the
neurodevelopmental
endpoint
is
not
the
only
endpoint
of
concern
for
human
health,
and
that
the
immunotoxicity
of
Hg
will
be
an
area
of
increasing
concern
in
the
future.
The
immunotoxicity
issue
is
reason
for
an
especially
precautionary
approach
to
development
of
a
benefits
calculation.
The
data
on
cardiovascular
endpoints
are
sufficiently
robust
at
this
point
that
they
should
be
included
in
a
benefits
assessment
for
Hg.
The
public
health
and
economic
burden
of
cardiovascular
disease
in
the
U.
S.
is
very
significant,
and
the
effect
of
Hg,
even
if
relatively
modest,
is
significant
and
worthy
of
inclusion
in
the
agency's
estimate
of
the
benefits
of
Hg
regulation.
In
our
opinion,
it
would
be
a
mistake
for
the
agency
to
ignore
any
of
these
endpoints
in
its
benefits
assessment,
even
though
the
commenter
agreed
that
neurodevelopment
in
children
is
an
especially
important
endpoint.
9­
255
The
focus
on
neurodevelopmental
health
of
children
Although
the
commenter
agreed
that
a
credible
benefits
assessment
for
this
rule
should
address
the
well­
established
neurodevelopmental
health
effects
of
Hg
toxicity,
they
did
not
believe
this
should
be
the
exclusive
focus.
A
July
2000
review
by
the
National
Academy
of
Sciences
(
NAS)
concluded
that
neurodevelopmental
effects
were
the
most
sensitive
and
well­
documented
effects
of
MeHg
exposure,
based
on
the
best
available
data
at
the
time.
EPA's
RfD
of
0.0001
milligrams
per
kilogram
of
body
weight
per
day
(
mg/
kg/
day)
derives
from
a
neurodevelopmental
endpoint,
and
the
NAS
determined
that
EPA's
RfD
"
is
a
scientifically
justified
level
for
the
protection
of
public
health."
The
RfD
was
based
on
three
epidemiological
studies
of
prenatal
MeHg
exposure
in
the
Faroe
Islands,
New
Zealand,
and
Seychelles
Islands.
These
studies
examined
neurodevelopmental
outcomes
through
the
administration
of
numerous
partial
or
full
assessments
of
IQ,
problem
solving,
social
and
adaptive
behavior,
language
functions,
motor
skills,
attention,
memory,
and
other
functions.
Although
the
NAS
panel
found
that
all
three
studies
are
well­
designed,
prospective,
longitudinal
studies,
it
also
concluded
that,
"
given
the
strengths
of
the
Faroe
Islands
study,
it
is
the
most
appropriate
study
for
deriving
an
RfD."

However,
as
discussed
above,
Hg
exposure
has
also
now
been
linked
to
immune
system
dysfunction,
other
developmental
effects,
and
cardiovascular
disease.
These
potentially
permanent,
severe,
and
life­
threatening
effects
are
associated
with
environmentally
relevant
levels
of
Hg
exposure.
When
calculating
the
benefits
of
reducing
Hg
exposure
it
would
be
a
mistake
to
focus
on
the
neurodevelopmental
outcomes
to
the
exclusion
of
all
of
these
other
important
health
endpoints.
To
do
so
would
ignore
the
extensive
new
scientific
information
on
MeHg
and
would
also
seriously
underestimate
the
health
benefits
of
Hg
reduction.

IQ
as
an
endpoint
for
quantification
of
neurodevelopmental
effects
EPA
asks
for
comments
regarding
whether
IQ
is
an
appropriate
metric
for
quantifying
neurodevelopmental
impacts.
It
is
not
a
sufficient
one.
The
array
of
neuropsychological
deficits
associated
with
even
low
levels
of
Hg
exposure
during
early
life
stages
includes
behavioral
alterations
and
impaired
language,
attention,
memory,
and,
to
a
lesser
extent,
visuospatial
and
motor
functions.
Most
concerning,
some
of
these
effects
are
detectable
at
exposure
levels
currently
considered
acceptable
by
EPA.
It
is
clear
that
Hg
effects
are
not
localized
to
discrete
brain
regions
when
these
exposures
occur
prenatally
or
perinatally,
and
any
credible
benefits
analysis
must
quantitatively
account
for
the
broad
spectrum
of
brain
damage
associated
with
Hg.
Measurements
of
IQ
are
inadequate
to
capture
fully
the
profile
of
Hg
neurodevelopmental
toxicity;
IQ
tests
do
not
capture
impairments
of
manual
dexterity,
motor
functions,
and
hand­
eye
coordination,
all
known
to
be
associated
with
Hg
exposure.
Accordingly,
to
be
more
credible,
a
benefits
analysis
must
explicitly
calculate
the
sweeping
benefits
of
reduced
exposure
for
protection
of
the
fragile,
complex
developing
nervous
system.

Quantification
and
economic
valuation
of
neurodevelopmental
and
other
health
effects
An
economic
valuation
will
not
be
complete
unless
it
can
account
for
adverse
effects
of
9­
256
early­
life
exposure
to
Hg
on
cognitive
abilities,
neurodevelopmental
deficits
such
as
motor
disabilities
and
hand­
eye
co­
ordination,
immune
system
toxicity,
impaired
growth
and
development,
and
cardiovascular
disease.
A
full
economic
valuation
of
Hg
toxicity
must
quantitatively
account
for
the
full
array
of
neurodevelopmental
deficits
known
to
be
associated
with
Hg,
such
as
learning,
memory,
IQ,
visuospatial,
and
motor
deficits.
In
addition,
an
economic
valuation
that
claims
to
represent
Hg
toxicity
must
also
account
for
Hg­
associated
immunotoxicity,
reproductive
effects
and
cardiovascular
disease
risks.
If
this
cannot
be
done,
perhaps
because
the
data
are
not
sufficiently
robust
for
such
a
calculation,
then
the
resulting
uncertainty
and
potential
for
error
must
be
stated,
and
incorporated
into
the
final
analysis.

The
commenter
supported
a
comprehensive
approach
for
the
development
of
a
credible
benefits
analysis,
but
emphasized
that
any
such
analysis
must
consider
the
variability
within
the
data
and
the
uncertainty
inherent
in
the
exposure
assessment
and
model
methodology.
It
may
be
helpful
in
developing
an
integrative,
data­
comprehensive
benefits
model,
for
EPA
to
review
the
NAS
report.
The
NAS
used
data
from
the
Faroe
Islands,
New
Zealand,
and
the
Seychelles
Islands
studies
to
develop
an
integrative
analysis
of
Hg
toxicity.
EPA
itself
developed
the
RfD
of
0.1
g/
kg
body
weight
per
day
for
MeHg
by
integrating
data
from
these
three
studies,
so
it
is
apparent
that
the
agency
is
capable
of
such
an
integrated
assessment.
It
is
consistent
with
EPA
practice
to
consider
the
weight
of
evidence
of
the
available
literature.
The
NAS
approach
relied
upon
a
hierarchical
random
effects
model
designed
to
take
proper
account
of
appropriate
study­
to­
study
and
outcome­
to­
outcome
heterogeneity
across
the
studies.
Such
a
model
provided
a
useful
tool
for
separating
random
versus
systematic
variation
and
thereby
provides
more
stable
estimates
of
study­
specific
and
outcome­
specific
benchmark
doses.
The
effect
of
the
hierarchical
modeling
was
to
smooth
away
much
of
the
random
variability
observed
in
the
original
data,
particularly
the
more
extreme
values.

Use
of
the
K=
1
model
PA
seeks
comment
on
whether,
by
using
a
K­
model
with
K=
1,
it
should
presume
that
reducing
Hg
exposure
will
reduce
adverse
health
effects
in
a
linear
fashion.
The
researchers
analyzing
data
from
the
Faroe
Islands
study
have
investigated
various
models
applied
to
their
data
set.
They
have
found
that
a
log
curve
is
the
best
fit
with
the
data,
but
the
improvement
over
a
linear
curve
is
of
borderline
statistical
significance
(
p=
0.06).
Accordingly,
the
researchers
have
used
a
linear
model
for
their
analyses.
It
appears
that
the
choice
of
either
a
linear
or
a
log
model
is
reasonable.
It
would
be
unreasonable,
however,
for
the
agency
to
continue
the
past
practice
of
using
a
threshold
model
with
a
NOAEL,
as
such
a
model
is
unsupported
by
the
existing
data.

An
alternative
approach
could
involve
doing
a
benchmark
dose
extrapolation
that
incorporates
all
available
data
on
Hg
toxicity.
The
benchmark
dose
(
BMDL)
method
is
coming
into
increasing
use
as
a
pragmatic
way
of
dealing
with
dose­
response
relationships
deriving
from
multiple
endpoints
and
multiple
datasets,
without
a
clear
indication
of
a
threshold,
such
as
the
Hg
data.
The
BMDL
is
the
lower
95
percent
confidence
limit
of
the
dose
of
a
substance
that
increases
the
risk
of
an
abnormal
response
by
a
benchmark
response,
such
as
a
5­
10
percent
response
compared
with
a
reference
population.
Such
an
approach
would
require
the
use
of
an
9­
257
uncertainty
factor;
because
a
BMDL
is
not
a
no­
effect
level,
an
additional
multiplier
is
necessary
to
provide
sufficient
assurance
that
the
public
at
large
would
be
protected
from
an
adverse
health
effect.

Use
of
a
linear
dose­
response
model
and
the
appropriateness
of
assuming
that
Hg
has
a
threshold
for
adverse
health
effects
The
data
from
the
Faroe
Islands
study
do
not
reveal
evidence
of
a
threshold
below
which
Hg
does
not
exhibit
some
toxic
effect
on
the
developing
brain.
Mechanistic
data
also
support
the
lack
of
a
threshold,
as
Hg
has
numerous
adverse
effects
on
neurons
that
would
not
be
expected
to
have
a
threshold
of
action.
Therefore
the
choice
of
a
linear
model
makes
the
most
sense
for
analysis
of
the
MeHg
data.

Recent
data
from
the
Faroe
Islands
study
indicate
that
the
BMDL
for
deficits
in
neurophysiological
function
is
more
likely
to
be
associated
with
5

g/
g
Hg
in
hair,
instead
of
the
11

g/
g
that
the
NAS
calculated,
meaning
that
the
neurological
effects
of
Hg
have
been
demonstrated
at
an
even
lower
dose
than
previously
reported.
The
difference
is
due
to
exposure
misclassification.
All
calculations
so
far
have
assumed
that
the
exposure
estimates
were
more
precise
than
they
really
are.
The
Faroe
Islands
research
team
recently
showed
that
hair­
Hg
is
somewhat
imprecise­
that
is,
in
this
case,
how
well
the
hair
measurements
reflected
the
true
cord­
blood
Hg
exposure.
Imprecise
exposure
assessments
result
in
an
underestimation
of
the
true
magnitude
of
the
effect
of
an
exposure
to
MeHg.
Recalculation
of
the
benchmark
dose
indicated
that
it
had
been
overestimated
by
a
factor
of
two.
Accordingly,
recalculating
the
exposure
limit
using
the
adjusted
benchmark
dose
would
result
in
a
limit
approximately
one­
half
the
one
used
by
EPA
in
calculating
the
RfD.

The
commenter
was
also
concerned
about
potential
industry
pressure
on
EPA
to
revise
the
RfD
or
to
undermine
any
conclusions
the
agency
has
made
about
risks
to
the
U.
S.
population.
The
commenter
was
aware
that
agency
officials
met
with
seafood
industry
representatives
in
February
2004.
Accordingly,
the
Clean
Air
Task
Force
requested
disclosure
of
materials
related
to
this
meeting
(
and
any
other
materials
related
to
this
or
other
similar
meetings)
pursuant
to
the
Freedom
of
Information
Act,
5
U.
S.
C.
§
552.
Although
EPA
received
that
request
on
November
2,
2004
and
is
required
to
"
respond
to
requests
no
later
than
20
working
days
from
the
date
the
request
is
received
and
logged
in,"
40
CFR
§
2.104(
a),
the
agency
has
not
provided
the
Clean
Air
Task
Force
with
a
substantive
response.
The
commenter
is
looking
forward
to
the
agency's
response
so
that
they
can
be
assured
that
the
seafood
industry
has
not
prompted
EPA's
newfound
interest
in
the
RfD.

Response:

In
developing
the
RfD,
the
Agency
did
rely
on
benchmark
dose
modeling
as
the
most
appropriate
method
of
quantifying
the
dose­
effect
relationship
in
the
three
principal
studies,
which
was
also
the
recommendation
of
the
NRC
(
2000).
EPA
chose
not
to
make
a
numerical
adjustment
between
cord­
blood
and
maternal­
blood
mercury.
The
relationship
between
9­
258
cord­
blood
and
maternal­
blood
mercury
is
considered
subject
to
variability
and
uncertainty,
and
was
included
in
the
determination
of
the
uncertainty
factor.

The
RIA
includes
an
assessment,
to
the
extent
possible
given
our
scientific
understanding
of
mercury
and
its
behavior
in
the
environment
and
impacts
on
human
health,
of
the
health
benefits
associated
with
the
proposed
regulatory
options.
Due
to
limitations
in
our
current
understanding
of
these
technical
areas
related
to
mercury
this
benefit
analysis
is
limited
to
the
self­
caught
freshwater
fish
consumption
pathway
and
to
IQ
deficits
in
prenatally­
exposed
infants.
In
keeping
with
precedent
in
evaluating
benefits
of
air
regulations
(
REFERENCE),
cobenefits
(
in
this
case
resulting
from
potential
reductions
in
direct
PM2.5)
are
also
included
in
the
RIA.

EPA
concurs
with
the
National
Academy
of
Sciences,
that
a
variety
of
health
endpoints
may
be
associated
with
methylmercury
exposure
in
addition
to
IQ
(
e.
g.,
immune
system
effects,
cardiovascular
mortality
and
additional
neurodevelopmental
endpoints).
However,
there
is
insufficient
peer­
reviewed
evidence
at
this
time
for
conducting
formal
analysis
of
these
endpoints
for
inclusion
in
the
primary
benefits
estimate.

EPA
acknowledges
that
emission
control
equipment
used
to
reduce
mercury
emissions
may
reduce
emissions
of
other
pollutants
including
PM
and
associated
HAPs.
While
EPA
has
included
an
analysis
of
potential
cobenefits
associated
with
reductions
in
direct
PM2.5,
limitations
in
our
current
understanding
of
differential
toxicity
prevent
us
from
modeling
health
benefits
from
reduced
exposure
to
HAPs
associated
with
that
PM.
Similarly,
while
EPA
concurs
with
the
National
Academy
of
Sciences,
that
a
variety
of
health
endpoints
may
be
associated
with
methylmercury
exposure
in
addition
to
IQ
(
e.
g.,
immune
system
effects,
cardiovascular
mortality
and
additional
neurodevelopmental
endpoints),
there
is
insufficient
peer­
reviewed
evidence
at
this
time
for
conducting
formal
analysis
of
these
endpoints
for
inclusion
in
the
primary
benefits
estimate.

Comment:

One
commenter
(
OAR­
2002­
0056­
5465)
stated
that
at
the
most
fundamental
level,
EPA's
proposed
revised
benefits
assessment
appeared
to
suffer
from
the
same
flaw
that
undermined
its
initial
benefits
assessment
for
the
CAMR:
while
EPA
proposed
to
account
for
the
costs
and
benefits
of
the
Maximum
Achievable
Control
Technology
(
MACT)
and
cap­
and­
trade
alternatives
as
proposed
by
EPA
in
its
January
30,2004
proposed
rule,
EPA
failed
to
consider
whether
a
more
protective
rule
would
produce
an
even
more
favorable
accounting
of
costs
and
benefits.
As
Professors
Heinzerling
and
Steinzor
document,
this
failure
stood
in
stark
contrast
to
the
current
practice
of
the
Office
of
Management
and
Budget's
Office
of
Information
and
Regulatory
Affairs
in
implementing
EO12866.
Moreover,
as
numerous
commenters
have
pointed
out,
EPA's
proposed
approaches
rest
on
dubious
scientific
and
legal
footing;
a
legally
defensible
rule
would
in
fact
require
much
more
stringent
reductions
in
Hg
emissions
from
coal­
fired
utilities.
Against
this
backdrop,
EPA's
failure
to
consider
the
costs
and
benefits
of
a
more
stringent
rule
is
particularly
egregious.
9­
259
Second,
as
EPA
now
concedes,
it
cannot
accurately
assess
the
benefits
of
Hg
emissions
regulation
without
considering
the
independent
benefits
of
reducing
the
adverse
effects
of
Hg
contamination.
However,
in
order
to
produce
an
accurate
accounting,
EPA
must
not
define
narrowly
the
benefits
at
issue,
i.
e.,
EPA
cannot
consider
only
a
subset
of
the
direct
effects
on
human
health
(
and
then
only
those
that
are
quantifiable
or
monetizable).
Instead,
EPA
must
consider
broadly
the
direct
and
indirect
effects
on
human
health
and
well­
being.
Included
within
this
broader
definition
are
those
effects
felt
not
only
by
individual
humans
but
also
by
relevant
groups
(
e.
g.,
adverse
impacts
on
the
various
Ojibwe
and
other
tribes'
ability
to
continue
important
traditional,
cultural
and
religious
practices).
EPA
must
also
consider
the
effects
on
ecological
health.
The
commenter
thus
urged
EPA
to
refer
to
those
tribal
and
other
commenters,
e.
g.,
the
Forest
County
Potawatomi
Community
and
the
Fond
du
Lac
Tribe,
that
have
know
ledge
of
and
are
uniquely
positioned
to
speak
to
the
nature
and
extent
of
the
adverse
effects
of
Hg
contamination.

Finally,
EPA
does
not
appear
to
contemplate
any
assessment
of
the
distribution
of
the
costs
and
benefits
of
the
CAMR
and
more
protective
alternatives.
However,
as
Professor
O'Neill
demonstrates,
various
subpopulations'
different
circumstances
of
exposure
mean
that
the
adverse
effects
of
Hg
reductions
that
are
delayed
and/
or
diminished
will
not
be
distributed
equally.
Rather,
the
harms
will
be
visited
disproportionately
on
American
Indian
tribes
and
their
members
 
especially
those
in
the
Great
Lakes
states,
where
there
is
a
likelihood
of
"
hot
spots"
under
the
EPA's
proposed
cap­
and­
trade
approach
 
and
on
other
communities
of
color
and
low­
income
groups.
Indeed,
it
is
clear
from
the
preamble
to
the
proposed
CAMR
that
the
EPA
is
well
aware
of
who
it
is
that
will
be
adversely
affected
by
a
more
lenient
rule.
In
order
to
fulfill
its
obligations
under
EO12898
regarding
environmental
justice
 
as
well
as
its
obligations
under
the
federal
trust
responsibility,
treaties,
and
various
other
legal
doctrines
 
EPA
must
assess
and
address
the
distributive
implications
of
its
proposed
rule.

Response:

EPA
included
four
potentially
high­
risk
populations
in
the
RIA,
including:
(
a)
high­
end
recreational
fisher
anglers
(
with
consumption
rates
at
or
above
the
95th
percentile
for
this
group),
(
b)
economically
disadvantaged
high­
end
consumers
with
poverty­
status
income
and
fish
consumption
rates
at
or
above
the
95th
percentile
for
freshwater
anglers,
(
c)
Hmong
in
Minnesota
and
Wisconsin
and
(
d)
Chippewa
in
Minnesota,
Wisconsin
and
Michigan.
These
special
population
are
intended
to
provide
coverage
for
groups
of
individuals
who
through
choice,
necessity
or
socio­
cultural
practices
consume
relatively
high
levels
of
self­
caught
freshwater
fish.
Inclusion
of
these
four
special
populations
is
also
intended
to
support
consideration
of
distributional/
equity
in
relation
to
EGU­
based
environmental
regulation
(
i.
e.,
would
a
subset
of
the
US
population
benefit
disproportionately
from
regulations
to
reduce
mercury
emissions
from
EGUs)?

Fish
consumption
rates
for
all
four
special
populations
have
been
developed
based
on
peer­
reviewed
survey
data
that
are
representative
of
the
particular
group
of
interest.
In
the
case
of
the
Chippewa,
we
have
used
a
mean
value
obtained
from
the
literature
(
see
RIA
Chapter
10
9­
260
for
additional
details).
However,
it
was
not
possible
to
identify
a
high­
end
percentile
consumption
rate
based
on
peer­
reviewed
literature
and
consequently,
the
mean
consumption
rate
was
used
in
the
benefits
analysis
without
consideration
for
variability
in
fish
consumption
rates
across
individuals.
However,
in
response
to
information
(
including
that
provided
by
this
commentor),
EPA
has
conducted
a
sensitivity
analysis
for
high
end
fish
consumption
by
the
Chippewa
population
using
(
a)
the
maximum
delta
fish
tissue
concentration
modeled
in
the
RIA
for
Option
1
and
Option
2
for
the
Chippewa
(
i.
e.,
the
maximum
change
in
MeHg
fish
tissue
concentrations
modeled
for
the
Chippewa
under
CAMR
Options
1
and
2)
and
(
b)
the
maximum
seasonal
fish
consumption
rate
provided
in
the
NODA
comments
(
i.
e.,
393.8
g/
day).
The
results
suggest
that
total
IQ
reductions
under
Option
1
and
2,
even
under
these
conservative
assumptions
(
i.
e.,
highest
change
in
mercury
fish
tissue
concentrations
under
Option
1
and
Option
2
and
the
highest
seasonal
fish
consumption
rate),
are
relatively
low
at
0.02
IQ
points
per
child.
This
relatively
low
IQ
benefit
for
this
conservative
scenario
reflects
the
fact
that,
while
states
where
the
Chippewa
are
located
may
have
relatively
high
absolute
(
total)
MeHg
concentrations
in
target
fish
species,
modeled
EGU
deposition
over
these
areas
is
relatively
low
and
consequently,
CAMR
is
likely
to
produce
smaller
changes
in
mercury
fish
tissue
concentrations
compared
with
other
areas
where
EGU
deposition
is
higher.
These
findings
argue
against
a
distributional
equity
concern
for
the
Chippewa
in
this
portion
of
the
study
area
(
although
this
conclusion
needs
to
be
considered
in
the
context
of
the
overall
precision
and
specificity
of
the
benefits
model
used
in
this
RIA
which
is
not
intended
for
site­
specific
analysis
and
was
developed
for
application
at
the
regional­
level).

EPA
has
used
a
cost­
of­
illness
function
based
on
lost
earnings
resulting
from
methylmercury
exposure
as
the
basis
for
its
primary
benefits
estimate
in
the
RIA
(
i.
e.,
prenatal
methylmercury
exposure
through
maternal
consumption
producing
IQ
decrements
in
children
which
translate
into
lost
earnings
later
in
life).
This
valuation
function,
which
is
based
on
the
approach
used
in
past
EPA
regulations
concerning
lead
exposure,
also
considers
the
impact
of
lowered
IQ
on
years
of
education
achieved.
EPA
acknowledges
that
because
this
function
is
based
on
cost­
of­
illness
and
not
willingness­
to­
pay
(
WTP),
it
likely
represents
a
lower
bound
for
valuation
of
the
IQ
decrements
and
that
a
more
comprehensive
WTP­
based
function
would
capture
other
factors
such
as
those
listed
by
the
commentor
above.
Note,
EPA
did
not
use
a
WTP­
based
function
in
the
benefits
analysis
because
peer­
reviewed
literature
does
not
support
derivation
of
such
a
function
at
this
time.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
noted
that
EPA
has
requested
comments
as
to
how
reductions
in
population­
level
exposures
of
Hg
will
improve
public
health.
(
Question
1)
The
commenter
noted
that
it
is
important
to
understand
that
there
is
a
threshold
for
Hg
levels
in
the
blood
below
which
there
are
no
effects.
This
is
in
contrast
to
lead,
which
appears
to
have
no
clear
threshold
level.
Unlike
lead
a
significant
(>
50
percent)
percentage
of
atmospheric
Hg
is
from
natural
sources.
Mercury
has
been
present
in
fish
tissue
prior
to
the
industrial
revolution.
EPA
has
selected
an
RfD
for
Hg
in
maternal
blood
(
5.8
ppb)
that
serves
as
a
de­
facto
threshold.
This
number,
which
is
10
times
below
the
threshold
number
developed
from
the
Faroe
Islands
study
9­
261
and
14
times
lower
than
the
WHO
level
of
concern,
is
very
conservative.
This
commenter
believes
that
if
an
unrealistically
low
threshold
(
ULT)
for
Hg
blood
levels
were
used
to
estimate
benefits,
reductions
in
blood
levels
between
the
true
threshold
and
the
ULT
would
create
the
appearance
of
a
benefit
where
there
is
none.

EPA
has
requested
comments
as
to
the
appropriateness
of
using
IQ
as
an
endpoint
for
both
quantifying
neurological
development
and
the
benefit
analysis
for
reduced
exposure
to
MeHg.
In
addition,
EPA
requested
comments
on
the
appropriateness
of
a
linear
dose
response
model
evaluating
health
impacts.
The
commenter
noted
that
there
is
a
concern
that
EPA
may
wish
to
develop
a
relationship
between
Hg
emissions
and
general
population
IQ.
If
this
relationship
were
then
coupled
with
an
imputed
value
for
increased
IQ
for
the
general
population,
large
estimated
benefits
could
be
generated
that
would
not
exist,
since
there
is
no
evidence
of
IQ
impact
at
blood
Hg
levels
greater
than
the
RfD
but
below
the
Faroe
Island
threshold
level.
There
are
opportunities
to
calculate
an
imputed
value
for
IQ
changes,
for
example,
recent
work
by
Jones
and
Schneider
estimates
that
a
1
point
increase
in
national
IQ
is
associated
with
a
0.16
percent
annual
increase
in
GNP.
This
commenter
believes
that
there
is
also
a
concern
that
assuming
a
linear
response
between
blood
Hg
and
IQ
would
lead
to
an
imputed
benefit
for
reducing
blood
Hg
below
the
threshold
level,
again
creating
benefits
that
do
not
exist.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
notes
that
EPA's
successful
lead
reduction
program
is
not
an
appropriate
model
for
Hg.
Lead
is
a
pollutant
that
has
been
linked
to
neurological
damage
similar
to
that
of
Hg.
In
the
late
1970s,
EPA
initiated
a
successful
program
designed
to
eliminate
all
lead
emissions
into
the
environment
primarily
through
the
phase­
out
of
leaded
gasoline.
Since
airborne
lead
emissions
are
linked
to
blood
lead
levels
in
children
and
related
neurological
impacts,
it
may
appear
reasonable
to
utilize
the
lead
elimination
model
for
dealing
with
Hg.
However,
there
are
important
reasons
why
the
program
to
reduce
lead
(
total
elimination
of
air
emissions)
is
not
appropriate
for
dealing
with
Hg.

°
Virtually
all
airborne
lead
is
attributed
to
anthropogenic
sources
while
a
large
percentage
of
airborne
Hg
(>
50
percent)
is
due
to
natural
sources.
It
is
impossible
to
eliminate
all
airborne
Hg
emissions.

°
Lead
emissions
and
ambient
lead
concentrations
are
primarily
associated
with
urban
areas
while
Hg
emissions
and
ambient
Hg
concentration
are
global.

°
While
there
appears
to
be
no
lower
limit
for
neurological
impacts
for
lead
blood
levels,
Hg
blood
levels
have
a
clear
threshold
below
which
there
are
no
neurological
impacts.

°
While
neurological
impacts
were
clearly
shown
at
blood
lead
levels
present
in
urban
US
children
in
the
1970s,
no
such
neurological
impacts
have
been
noted
or
documented
at
Hg
blood
levels
currently
found
in
American
child­
bearing
age
women
or
children.
9­
262
This
commenter
believes
that
EPA
should
consider
the
loss
of
health
benefits
associated
with
reduced
fish
consumption
due
to
an
overly
conservative
RID
for
Hg
blood
levels
in
determining
net
health
benefits
due
to
the
CAMR.
The
vast
majority
of
health
studies
have
concluded
that
the
benefits
of
fish
consumption
by
all
segments
of
the
general
population
far
outweigh
any
effects
due
to
blood
Hg
levels
greater
than
EPA's
RID
and
at
levels
approaching
the
WHO
level
of
concern.
The
use
of
the
RID
as
the
basis
for
calculating
fish
warning
Hg
levels
has
resulted
in
a
reduction
in
fish
consumption
and
the
related
loss
of
health
benefits
to
the
public.
The
commenter
supports
the
comments
of
the
Center
for
Science
and
Public
Policy
in
this
regard.

In
conclusion,
the
commenter
believes
that
the
combination
of
(
1)
an
overly
conservative
blood
Hg
threshold
and
a
linear
dose
response
with
assumed
benefits
accruing
below
the
threshold
level
along
with
(
2)
the
failure
to
properly
account
for
the
loss
of
health
benefits
due
to
reduced
fish
consumption
based
on
EPA's
RID
will
produce
unwarranted
and
unrealistically
high
estimated
benefits
from
Hg
emission
reductions
from
the
proposed
CAMR.

Response:

As
described
in
other
responses,
the
Agency
has
high
confidence
in
the
RfD
for
methylmercury.
EPA
encourages
the
public
to
vary
the
species
and
sources
of
fish
in
order
to
obtain
the
benefits
of
fish
consumption
while
avoiding
elevated
exposures
to
methylmercury.
The
fish
advisory
developed
jointly
with
the
Food
and
Drug
Administration
emphasizes
the
benefits
of
including
fish
in
a
healthy
diet
while
informing
the
public
on
ways
to
reduce
methylmercury
exposure
(
http://
www.
epa.
gov/
waterscience/
fishadvice/
advice.
html).

Comment:

The
commenter
(
OAR­
2002­
0056­
5455)
also
wished
to
comment
on
Step
5
of
the
NODA
addressing
cost/
benefit
analyses
and
how
Hg
reduction
will
improve
human
health.
The
commenter
found
that
EPA's
benefits
analysis
did
nothing
to
address
the
importance
of
fishing
as
a
cultural
practice.
There
was
no
way
to
place
a
dollar
amount
on
the
benefit
to
spiritual
well
being
as
a
result
of
practicing
a
centuries­
old
tradition
and
passing
it
on
to
our
children.
In
a
more
concrete
measurement,
EPA
did
nothing
to
address
replacing
a
subsistence
food
source
that
provided
a
significant
amount
of
nutrition
for
the
commenter's
members.
In
making
a
local,
easily
obtainable
food
source
inedible
due
to
poisoning,
EPA
should
calculate
the
costs
that
will
be
incurred
in
finding
alternate
sources
of
nutrition.
The
commenter
was
also
unaware
of
any
attempts
EPA
had
made
to
quantify
the
costs
of
the
learning
and
educational
problems
that
exposed
children
may
experience.
For
example,
the
loss
in
lifetime
earnings
resulting
from
lowered
IQ's
in
the
generalized
population
as
a
result
of
Hg
poisoning
has
been
estimated
at
$
2.3
billion
per
year.
By
refusing
to
set
adequate
MACT
standards,
EPA
was
heaping
most
of
this
loss
on
the
heads
of
native
people.
Another
error
in
EPA's
cost/
benefit
analysis
came
from
the
projection
of
$
15
billion
in
savings
due
to
health­
related
benefits
from
their
proposed
rule.
These
were
simply
health
benefits
that
accrued
from
EPA's
very
substandard
proposal.
If
a
proper
MACT
standard
were
set
in
place,
additional
billions
of
dollars
could
be
saved.
9­
263
EPA
had
also
failed
to
assess
tourism­
related
impacts.
Tourism
brought
in
$
9.8
billion
annually
in
Minnesota
alone.
Of
this
total,
sport
fishing
enthusiasts
spend
$
1.58
billion,
or
16
percent.
Although
it
was
unknown
to
what
level
fish
advisories
impacted
these
number,
fishing
and
tourism
brought
in
income
that
the
state
of
Minnesota
could
not
afford
to
lose.
The
other
Great
Lakes
states
of
Wisconsin,
Michigan,
Illinois,
Indiana,
and
Ohio
face
similar
situations.
Together,
these
states,
along
with
Minnesota,
attract
7.8
million
anglers
annually
who
spend
$
5
billion
in
fishing­
related
dollars.
Although
these
are
not
directly
health­
related
issues,
they
certainly
need
to
be
addressed
in
EPA's
economic
considerations.

Response:

EPA
has
used
a
cost­
of­
illness
function
based
on
lost
earnings
resulting
from
methylmercury
exposure
as
the
basis
for
its
primary
benefits
estimate
in
the
RIA
(
i.
e.,
prenatal
methylmercury
exposure
through
maternal
consumption
producing
IQ
decrements
in
children
which
translate
into
lost
earnings
later
in
life).
This
valuation
function,
which
is
based
on
the
approach
used
in
past
EPA
regulations
concerning
lead
exposure,
also
considers
the
impact
of
lowered
IQ
on
years
of
education
achieved.
EPA
acknowledges
that
because
this
function
is
based
on
cost­
of­
illness
and
not
willingness­
to­
pay
(
WTP),
it
likely
represents
a
lower
bound
for
valuation
of
the
IQ
decrements
and
that
a
more
comprehensive
WTP­
based
function
would
capture
other
factors
such
as
those
listed
by
the
commentor
above.
Note,
EPA
did
not
use
a
WTP­
based
function
in
the
benefits
analysis
because
peer­
reviewed
literature
does
not
support
derivation
of
such
a
function
at
this
time.

Comment:

Four
commenters
(
OAR­
2002­
0056­
2224,
­
2835,
­
2867,
­
2922)
filed
comments
to
supplement
EPA's
discussion
of
its
statutory
authority
to
regulate
under
CAA
section
111
and
to
establish
a
cap­
and­
trade
program.
They
stated
that
CAA
section
111
confers
broad
legal
authority
for
the
regulation
of
existing
sources
under
a
Federal­
State
partnership.
The
legislative
history
and
the
relationship
between
the
plans
developed
for
the
State­
Federal
partnerships
under
CAA
section
110
and
section
111
further
supports
EPA's
determination
that
a
flexible
emissions
trading
program
can
be
implemented
under
section
111(
d).

The
commenters
noted
that
this
partnership
contemplates
EPA
establishing
"
standards
of
performance"
at
the
national
level
and
each
state
developing
a
regulatory
program
for
implementing
and
enforcing
those
standards
at
the
state
level.
The
commenters
pointed
out
that
the
statute
explicitly
notes
that
the
Federal­
State
partnership
under
CAA
section
111(
d)
is
to
be
modeled
after
the
regulatory
process
used
under
CAA
section
110.
In
that
regulatory
context,
CAA
section
110
provides
States
with
wide
latitude
in
developing
emissions
control
strategies
for
achieving
Federal
air
quality
goals
 
National
Ambient
Air
Quality
Standards
(
NAAQS)
established
by
EPA
at
the
national
level.

Both
the
statute
and
legislative
history
confirm
that
Congress
delegated
broad
legal
authority
to
adopt
flexible
regulatory
mechanisms
for
controlling
existing
sources
under
section
9­
264
111(
d)(
1).
This
broad
delegation
of
authority
provides
sufficient
authority
for
EPA
to
establish
flexible
"
standards
of
performance"
that
need
not
prescribe
when,
how,
and
the
degree
to
which
each
affected
unit
must
achieve
that
emissions
limitation
 
either
on
a
unit­
by­
unit
basis
or
facility­
by­
facility
basis.
In
addition,
the
CAA
authorizes
States
to
implement
and
enforce
those
standards
of
performance
through
cap­
and­
trade
program
or
other
such
flexible,
market­
based
mechanism
that
implements
the
reduction
requirement
imposed
under
the
standard
of
performance,
while
taking
into
consideration
"
the
remaining
useful
life"
of
the
source
as
well
as
"
other
factors."
EPA's
proposed
trading
scheme
is
one
effective
mechanism
for
States
to
address
concerns
regarding
existing
units
whose
remaining
useful
life
is
limited
such
that
the
purchase
of
allowances
may
be
appropriate
in
lieu
of
making
additional
major
pollution
control
investments
at
those
units.
Commenter
OAR­
2002­
0056­
2835
described
in
detail
how
this
interpretation
is
confirmed
in
the
legislative
history
to
CAA
section
111(
d).

Another
indication
of
the
broad
discretion
accorded
to
EPA
and
States
in
implementing
and
enforcing
standards
of
performance
under
section
111
(
d)(
1)
is
the
relationship
that
this
section
has
with
section
110.
Section
111
(
d)(
1)
requires
EPA
to
promulgate
regulations
that
establish
SIP­
like
procedures
similar
to
those
in
section
110
to
be
used
by
States
in
submitting
their
plans.
The
CAA
section
111(
d)
plans
and
SIP
programs
are
complementary
to
one
another
 
in
particular,
a
State's
plan
under
section
110
(
or
section
172,
for
non­
attainment
areas)
can
be
used
to
meet
the
standards
under
section
111(
d).
States
can
thus
use
the
SIP
regulatory
tools
in
CAA
sections
110(
a)(
2)(
A)
and
172(
c)(
6)
to
establish
"
enforceable
emissions
limitations
and
other
control
measures"
to
achieve
this
end.
One
such
regulatory
tool
available
to
States
explicitly
referenced
under
these
sections
is
the
adoption
of
"
economic
incentives
such
as
fees,
marketable
permits,
and
auctions
of
emissions
rights,"
when
developing
a
plan
to
comply
with
the
standards
under
section
111(
d)(
1).

This
complementary
relationship
was
confirmed
in
EPA's
guidance
for
implementing
the
Emission
Guidelines
for
Municipal
Waste
Combustors
established
under
CAA
sections
111(
d)
and
129.
EPA's
guidance
explained
that
where
the
SIP
requirements
are
adequate
to
meet
the
section
111(
d)/
129
standard
­
which
are
required
to
be
more
rigorous
than
emission
guidelines
under
only
section
111(
d)
­
the
State
has
the
authority
to
submit
a
section
111(
d)/
129
plan
that
relies
on
the
requirements
of
the
SIP
to
meet
the
section
111
(
d)/
129
standard.
The
commenter
adds
that
the
section
111(
d)/
129
rule
for
Municipal
Waste
Combustors
also
clearly
contemplated
that
States
would
use
trading
when
implementing
and
enforcing
the
standards­
the
rule
explicitly
provided
that
a
state
plan
could
"
establish
a
program
to
allow
owners
or
operators
of
municipal
waste
combustor
plants
to
engage
in
trading
of
nitrogen
oxides
emission
credits."

Commenter
OAR­
2002­
0056­
2867
stated
that
EPA
has
correctly
harmonized
these
conflicting
statutory
provisions,
and
interpreted
them
in
a
way
that
effectuates
the
purposes
of
the
statute
as
whole.
The
commenter
agreed
that
the
key
provision
in
the
definition
of
a
"
standard
of
performance"
under
CAA
section
111
is
the
phrase
"
the
best
system
of
emissions
reduction."
Since
this
phrase
is
not
defined
by
statute,
EPA
has
broad
discretion
in
determining
what
is
the
"
best
system
of
emissions
reduction,"
so
long
as
the
system
ultimately
selected
"
has
been
adequately
demonstrated."
The
commenter
pointed
out
the
definition
places
no
other
explicit
9­
265
statutory
constraints
on
EPA
in
making
this
determination,
except
that
it
must
consider
the
following
factors:
the
cost
of
achieving
the
Hg
reductions,
non­
air
quality
health
and
environmental
impacts,
and
energy
requirements.
The
commenter
concluded
that
the
statute
requires
the
standards
of
performance
be
based
on
"
the
degree
of
emission
limitation
achievable"
by
the
best
system
of
emissions
reduction
system
selected
by
EPA.
As
evidenced
by
the
success
of
other
cap­
and­
trade
programs
for
the
power
sector,
i.
e.,
the
NOx
SIP
Call
and
the
Title
IV
Acid
Rain
Program,
the
trading
program
approach
arguably
satisfies
the
statutory
requirement
for
setting
the
standard
of
performance
based
on
the
best
system
of
emission
reduction
for
the
electric
utility
source
category.

The
commenter
felt
it
is
important
to
note
that
the
statutory
definition
does
not
require
specific
units
or
facilities
to
install
emissions
control
technology.
In
addition,
the
definition
is
silent
on
whether
or
not
the
standard
of
performance
prescribing
specific
emissions
limits
should
directly
apply
on
a
unit­
by­
unit
or
facility­
by­
facility
basis.
The
commenter
also
noted
that
the
definition
is
silent
on
whether
each
unit
or
facility
must
achieve
specific
reduction
levels
continuously
or
averaged
over
a
specific
period
of
time.
(
Regarding
this
issue,
the
commenter
pointed
out
that
CAA
section
302(
1)
also
contains
a
definition
of
the
term
"
standard
of
performance,"
which
defines
the
term
to
mean
"
a
requirement
of
continuous
emission
reduction,
including
any
requirement
relating
to
the
operation
or
maintenance
of
a
source
to
assure
continuous
emissions
reduction."
It
appears
to
the
commenter
that
this
definition
would
not
be
controlling
for
purposes
of
setting
standards
of
performance
under
section
111,
given
that
Congress
chose
to
adopt
another
specific
definition
of
standard
of
performance
in
CAA
section
111.

Three
commenters
(
OAR­
2002­
0056­
2224,
­
2835,
­
2867)
emphasized
that
CAA
section
111(
d)(
1)
itself
does
not
independently
mandate
that
standards
of
performance
for
existing
sources
impose
a
source­
specific
requirement
for
continuous
emission
reduction.
Thus,
a
State
plan
incorporating
a
standard
of
performance
that
employs
a
cap­
and­
trade
mechanism
would
not
conflict
with
the
statutory
requirements
of
section
111(
d)(
1).
However,
a
strong
case
can
be
made
for
the
proposition
that
the
emissions
cap
and
allowance­
holding
requirement
in
EPA's
proposed
section
111(
d)
trading
program
impose
a
"
continuous
emissions
reduction"
requirement
on
affected
electric
utility
units.
The
proposed
cap­
and­
trade
program
establishes
a
permanent
cap
on
Hg
emissions
and
requires
affected
sources
to
hold
allowances
that
correspond
to
the
level
of
Hg
emissions
from
those
sources
at
all
times.
By
its
very
elements,
the
proposed
cap­
and­
trade
program
is
a
continuous
method
of
emission
reduction
given
that
there
is
no
point
in
time
when
an
affected
source
can
emit
Hg
without
holding
allowances
that
correspond
to
those
emissions.
EPA's
proposal
also
requires
continuous
emissions
monitoring
to
assure
that
a
source
complies
with
the
requirements
of
the
cap­
and­
trade
program
at
all
times.
Thus,
if
a
court
were
ever
to
construe
section
111(
d)(
1)
to
require
a
"
continuous
emission
reduction,"
the
features
of
EPA's
proposed
trading
program
should
meet
that
requirement.

The
legislative
history
of
the
term
"
standard
of
performance,"
does
not
specifically
reference
an
allowance
trading
system
as
a
regulatory
mechanism
for
controlling
emissions
under
CAA
section111(
d),
but
generally
reflects
Congress'
intent
that
existing
sources
be
accorded
9­
266
considerable
flexibility
in
meeting
the
section
111(
d)
standards.
Such
legislative
intent
for
compliance
flexibility
provides
general
support
for
EPA's
interpretation
that
the
term
"
standard
of
performance"
may
include
an
allowance
trading
program,
as
proposed
in
the
Hg
rule,
because
such
a
trading
program
accords
flexibility
to
sources.

According
to
the
commenter,
the
Senate
debate
on
the
1990
amendments
reinforces
this
statutory
interpretation,
in
light
of
Congress'
express
action
removing
any
specific
percent
reduction
requirement
from
the
concept
of
"
standards
of
performance."
As
an
example,
the
commenter
states
that
Senator
Baucus
explains
that
Congress
adopted
a
percentage
reduction
requirement
in
the
1977
CAA
Amendments
to
ensure
that
coal­
fired
electric
generating
units
did
not
rely
on
low­
sulfur
"
compliance"
coal
alone
to
meet
NSPS
for
SO2.
According
to
Senator
Baucus,
a
percentage
reduction
requirement
across
the
board
was
supposed
to
require
SO2
scrubbers
regardless
of
the
rank
of
coal
combusted;
however,
this
approach
accentuated
the
regional
split
over
coal
use
that
existed
prior
to
1977.
With
the
adoption
of
the
SO2
emissions
cap
under
the
Title
IV
acid
rain
program,
the
percentage
reduction
requirement
was
no
longer
necessary
and
could
in
fact
be
a
barrier
to
flexible
compliance
under
the
acid
rain
trading
program.
The
commenter
continues
that
accordingly,
Congress
elected
to
repeal
the
percent
reduction
requirement
during
the
1990
CAA
Amendments.

The
commenter
also
referenced
remarks
in
debate
by
Senator
Bond
during
the
1990
CAA
Amendments
that
also
pertain
to
the
removal
of
the
percentage
reduction
requirement
and,
indirectly,
the
continuous
emission
reduction
requirement.
Specifically,
Senator
Bond
explained
that
both
the
House
and
the
Senate
rejected
the
concept
of
the
percentage
reduction
and
"
directed
EPA
to
come
up
with
an
alternative
standard
that
would
allow
utilities
to
meet
it
in
the
most
flexible
manner
possible."
Senator
Bond
further
noted
that
the
new
standards
could
be
met
by
fuel
switching,
the
use
of
technology
and
fuel
switching,
by
technology
alone,
and
by
intermittent
controls
or
intermittent
operation.
Senator
Bond
continued
by
stating
that
"[
t]
he
way
the
language
is
constructed,
intermittent
controls
can
be
allowed
to
comply
with
this
section
of
the
act.
So
for
the
first
time
in
13
years
we
will
have
EPA
setting.
.
.
emission
levels
for
SO2
that
will
not
require
the
use
of
the
scrubbers
for
compliance."

The
commenter
stated
that
this
flexibility
was
not
intended
to
be
limited
to
utility
standards,
or
the
operation
of
the
Acid
Rain
Program,
but
was
to
be
afforded
to
all
sources
subject
to
"
standards
of
performance"
under
section
111.
The
commenter
felt
it
would
be
ironic
if
EPA
failed
to
take
advantage
of
the
flexibility
specifically
intended
by
Congress
to
benefit
the
utility
industry
in
the
context
of
developing
requirements
for
Hg
control,
since
EPA
itself
has
not
identified
any
particular
control
technology
as
the
basis
for
its
standards.

Response:

Section
111(
d)(
1)
authorizes
EPA
to
promulgate
regulations
that
establish
a
State
Implementation
Plan­
like
(
SIP­
like)
procedure
under
which
each
State
submits
to
EPA
a
plan
that,
under
subparagraph
(
A),
"
establishes
standards
of
performance
for
any
existing
source"
for
certain
air
pollutants,
and
which,
under
subparagraph
(
B),
"
provides
for
the
implementation
9­
267
and
enforcement
of
such
standards
of
performance."
Paragraph
(
1)
continues,
"
Regulations
of
the
Administrator
under
this
paragraph
shall
permit
the
State
in
applying
a
standard
of
performance
to
any
particular
source
under
a
plan
submitted
under
this
paragraph
to
take
into
consideration,
among
other
factors,
the
remaining
useful
life
of
the
existing
source
to
which
such
standard
applies."

Section
111(
a)
defines,
"(
f)
or
purposes
of...
section
(
111),"
the
term
"
standard
of
performance"
to
mean
a
standard
for
emissions
of
air
pollutants
which
reflects
the
degree
of
emission
limitation
achievable
through
the
application
of
the
best
system
of
emission
reduction
which
(
taking
into
account
the
cost
of
achieving
such
reduction
and
any
non­
air
quality
health
and
environmental
impact
and
energy
requirements)
the
Administrator
determines
has
been
adequately
demonstrated.

Taken
together,
these
provisions
authorize
EPA
to
promulgate
a
"
standard
of
performance"
that
States
must,
through
a
SIP­
like
system,
apply
to
existing
sources.
A
"
standard
of
performance"
is
defined
as
a
rule
that
reflects
emission
limits
to
the
degree
achievable
through
"
the
best
system
of
emission
reduction"
that
EPA
"
determines
has
been
adequately
demonstrated,"
considering
costs
and
other
factors.

A
cap­
and­
trade
program
reduces
the
overall
amount
of
emissions
by
(
i)
requiring
sources
to
hold
allowances
to
cover
their
emissions
on
a
one­
for­
one
basis;
(
ii)
limiting
overall
allowances
so
that
they
cannot
exceed
specified
levels
(
the
"
cap");
and
(
iii)
reducing
the
cap
to
less
than
the
amount
of
emissions
actually
emitted,
or
allowed
to
be
emitted,
at
the
start
of
the
program.
In
addition,
the
cap
may
be
reduced
further
over
time.
Authorizing
the
allowances
to
be
traded
maximizes
the
cost­
effectiveness
of
the
emissions
reductions
in
accordance
with
market
forces.
Sources
have
an
incentive
to
endeavor
to
reduce
their
emissions
cost­
effectively;
if
they
can
reduce
emissions
below
the
number
of
allowances
they
receive,
they
may
then
sell
their
excess
allowances
on
the
open
market.
On
the
other
hand,
sources
have
an
incentive
to
not
put
on
controls
that
cost
more
than
the
allowances
they
may
buy
on
the
open
market.

The
term
"
standard
of
performance"
is
not
explicitly
defined
to
include
or
exclude
an
emissions
cap
and
allowance
trading
program.
In
today's
action,
EPA
finalizes
its
proposal
to
interpret
the
term
"
standard
of
performance,"
as
applied
to
existing
sources,
to
include
a
capand
trade
program.

Because
Congress
did
not
speak
precisely
to
this
issue,
EPA's
interpretation
of
the
term
to
authorize
a
cap­
and­
trade
program
is
entitled
to
deference
and
should
be
upheld
by
a
Court
because
the
interpretation
is
reasonable.
Chevron,
U.
S.
A.,
Inc.
v.
Natural
Resources
Defense
Council,
Inc.,
467
U.
S.
837,
842­
73
(
1984).
This
interpretation
is
supported
by
a
careful
reading
of
the
section
111(
a)
definition
of
the
term,
quoted
above.

In
the
phrase,
"
standard
of
performance,"
the
first
operative
term
is
"
standard"
and
the
1
The
legislative
history
of
the
term,
"
standard
of
performance,"
does
not
address
an
allowance/
trading
system,
but
does
indicate
that
Congress
intended
that
existing
sources
be
accorded
flexibility
in
meeting
the
standards.
See
"
Clean
Air
Act
Amendments
of
1977,"
Committee
on
Interstate
and
Foreign
Commerce,
H.
R.
Rep.
No.
95­
294
at
195,
reprinted
in
4
"
A
Legislative
History
of
the
Clean
Air
Act
Amendments
of
1977,"
Congressional
Research
Service,
2662.
Because
Congress
intended
flexibility
for
existing
sources,
EPA
interprets
this
legislative
history
as
generally
supportive
of
interpreting
"
standard
of
performance"
to
include
an
allowance/
trading
program
because
such
a
program
accords
flexibility
to
sources.
The
legislative
history
contains
no
direct
indication
that
Congress
intended
to
preclude
EPA
from
implementing
section
111
for
existing
sources
through
a
cap­
and­
trade
program.

9­
268
standard
must
be
"
for
emissions
of
air
pollutants."
The
ordinary
definition
of
"
standard"
is
"[
a]
n
accepted
measure
of
comparison
for
quantitative
or
qualitative
value,"
or
"
criterion."
Webster's
II
New
Riverside
University
Dictionary
1131
(
1984).
Under
the
cap­
and­
trade
requirement,
each
existing
source
is
obligated
to
hold
an
allowance
for
each
unit
of
mercury
that
it
emits.
This
requirement
to
hold
allowances
sufficient
to
cover
emissions
meets
the
definition
of
the
term,
"
standard"
because
the
requirement
constitutes
a
means
of
measurement,
or
a
type
of
a
criterion,
"
for
emissions
of
air
pollutants."
That
is,
the
measure
or
criterion
for
a
source's
emissions
of
air
pollutants
is
the
amount
of
allowances
that
the
source
holds.

A
cap­
and­
trade
program
is
also
consistent
with
the
remaining
components
of
the
term
"
standard
of
performance,"
that
is,
the
"
standard
for
emissions
of
air
pollutants"
must
be
one
(
i)
"
which
reflects
the
degree
of
emission
limitation
achievable"
(
i.
e.,
which
requires
an
amount
of
emissions
reductions
that
can
be
achieved),
(
ii)
"
through
the
application
of
the
best
system
of
emission
reduction
which
(
taking
into
account
the
cost
of
achieving
such
reduction
and
any
nonair
quality
health
and
environmental
impact
and
energy
requirements)
the
Administrator
determines
has
been
adequately
demonstrated."
111
The
key
component
of
the
last
part
of
this
definition
is
the
phrase,
"
best
system
of
emission
reduction."
While
the
parenthetical
following
this
phrase
obligates
EPA
to
consider
the
factors
specified
in
that
parenthetical,
the
term
"
best
system"
itself
is
not
defined,
and
implicitly
accords
broad
discretion
to
the
Administrator.
The
term
"
system"
implies
a
broad
set
of
emissions
reductions,
and
the
term
"
best"
confers
upon
the
Administrator
the
authority
to
promulgate
regulations
requiring
a
system
that
he
or
she
considers
superior.
The
parenthetical
phrase
in
the
definition
mandates
consideration
of
certain
factors,
but
the
definition
does
not
indicate
how
to
weight
those
factors,
how
specifically
to
apply
them,
or
whether
other
factors
may
be
considered.
Nor
does
the
provision
provide
any
other
explicit
constraints
in
determining
the
"
best
system."
This
broad
authority
conferred
on
the
Administrator
supports
the
view
that
the
Administrator
is
authorized
to
interpret
a
cap­
and­
trade
program
as,
under
the
present
circumstances,
the
"
best
system,"
and
thus
as
authorized
under
section
111(
a)
and
(
d).

Nor
do
any
other
provisions
of
section
111(
d)
indicate
that
the
term
"
standard
of
performance"
may
not
be
defined
to
include
a
cap­
and­
trade
program.
Section
111(
d)(
1)(
B)
refers
to
the
"
implementation
and
enforcement
of
such
standards
of
performance,"
and
section
111(
d)(
1)
refers
to
the
State
"
in
applying
a
standard
of
performance
to
any
particular
source,"
2
This
interpretation
of
the
term
"
continuous"
is
consistent
with
the
legislative
history
of
that
term.
See
H.
R.
Rep.
No.
95­
294
at
92,
reprinted
in
4
Congressional
Research
Service,
A
Legislative
History
of
the
Clean
Air
Act
Amendments
of
1977,
2559.

9­
269
but
all
of
these
references
readily
accommodate
a
cap­
and­
trade
program.

Although
section
111(
a)
defines
"
standard
of
performance"
for
purposes
of
section
111,
section
302(
l)
defines
the
same
term,
"(
w)
hen
used
in
this
Act,"
to
mean
"
a
requirement
of
continuous
emission
reduction,
including
any
requirement
relating
to
the
operation
or
maintenance
of
a
source
to
assure
continuous
emission
reduction."
The
term
"
continuous"
is
not
defined
in
the
CAA.

Because
section
111(
a)
defines
"
standard
of
performance"
for
purposes
of
section
111,
EPA
believes
that
the
section
302(
l)
definition
does
not
apply
to
section
111.
However,
even
if
the
section
302(
l)
definition
applied
to
the
term
"
standard
of
performance"
as
used
in
section
111(
d)(
1),
EPA
believes
that
a
cap­
and­
trade
program
meets
the
definition.
A
cap­
and­
trade
program
with
an
overall
cap
set
below
current
emissions
is
a
"
requirement
of...
emission
reduction."
Moreover,
it
is
a
requirement
of
"
continuous"
emissions
reductions
because
all
of
a
source's
emissions
must
be
covered
by
allowances
sufficient
to
cover
those
emissions.
That
is,
there
is
never
a
time
when
sources
may
emit
without
needing
allowances
to
cover
those
emissions.
22
We
note
that
EPA
has
on
one
prior
occasion
authorized
emissions
trading
under
section
111(
d).
(
The
Emission
Guidelines
and
Compliance
Times
for
Large
Municipal
Waste
Combustors
that
are
Constructed
on
or
Before
September
20,
1994;
40
CFR
Part
60,
subpart
Cb.)
This
provision
allows
for
a
NOx
trading
program
implemented
by
individual
States.
Section
60.33b(
C)(
2)
states,

A
State
plan
may
establish
a
program
to
allow
owners
or
operators
of
municipal
waste
combustor
plants
to
engage
in
trading
of
nitrogen
oxides
emission
credits.
A
trading
program
must
be
approved
by
the
Administrator
before
implementation.

Today's
proposal
is
wholly
consistent
with
this
prior
section
111(
d)
trading
provision.

Having
interpreted
the
term
"
standard
of
performance"
to
include
a
cap­
and­
trade
program,
EPA
must
next
"
determine"
that
such
a
system
is
"
the
best
system
of
emissions
reductions
which
(
taking
into
account
the
cost
of
achieving
such
reduction
and
any
non­
air
quality
health
and
environmental
impact
and
energy
requirements)...
has
been
adequately
demonstrated."
Section
111(
a)(
1).
EPA
has
determined
that
a
cap­
and­
trade
program
based
on
control
technology
available
in
the
relevant
time
frame
is
the
best
system
for
reducing
Hg
emissions
from
existing
coal­
fired
Utility
Units.

Since
the
passage
of
the
1990
Amendments
to
the
CAA,
EPA
has
had
significant
3
Non­
electricity
generating
units
are
also
included
in
the
States'
programs.

9­
270
experience
with
the
cap­
and­
trade
program
for
utilities.
The
1990
Amendments
provided,
in
Title
IV,
for
the
acid
rain
program,
a
national
cap­
and­
trade
program
that
covers
SO2
emissions
from
utilities.
Title
IV
requires
sources
to
hold
allowances
for
each
ton
of
SO2
emissions,
on
a
one­
for­
one
basis.
EPA
allocates
the
allowances
for
annual
periods,
in
amounts
initially
determined
by
the
statute,
that
decrease
further
at
a
statutorily
specified
time.
This
program
has
resulted
in
an
annual
reduction
in
SO2
emissions
from
utilities
from
15.9
million
tons
in
1990
(
the
year
the
Amendments
were
enacted)
to
10.6
million
tons
in
2003
(
the
most
recent
year
for
which
data
was
available).
Emissions
in
2003
were
41
percent
lower
than
1980,
despite
a
significant
increase
in
electrical
generation.
At
full
implementation
after
2010,
emissions
will
be
limited
to
8.95
million
tons,
a
50
percent
reduction
from
1980
levels.
The
Acid
Rain
program
allowed
sources
to
trade
allowances,
thereby
maximizing
overall
cost­
effectiveness.

In
addition,
in
the
1998
NOx
SIP
Call
rulemaking,
EPA
promulgated
a
NOx
reduction
requirement
that
affects
21
States
and
the
District
of
Columbia
("
Finding
of
Significant
Contribution
and
Rulemaking
for
Certain
States
in
the
Ozone
Transport
Assessment
Group
Region
for
Purposes
of
Reducing
Regional
Transport
of
Ozone;
Rule,"
63
FR
57,356
(
October
27,
1998)).
All
of
the
affected
jurisdictions
are
implementing
the
requirements
through
a
capand
trade
program
for
NOx
emissions
primarily
from
utilities.
33
These
programs
are
contained
in
SIP
that
EPA
has
approved;
and
EPA
is
administering
the
trading
programs.
However,
for
most
States,
the
requirements
did
not
need
to
be
implemented
until
May,
2004.

Further,
EPA
recently
promulgated
the
Clean
Air
Implementation
Rule
(
CAIR),
which
requires
SIP
revisions
in
28
States
and
the
District
of
Columbia
to
reduce
emissions
of
SO2
and
or
Nox
because
those
emissions
contribute
significantly
to
attainment
problems
for
the
PM2.5
or
8­
hour
ozone
national
ambient
air
quality
standards
in
downwind
States.
The
EPA
Administrator
signed
the
CAIR
on
March
10,
2005,
and
the
rule
and
associated
documents
are
available
at
http://
www.
epa.
gov/
cair/
rule.
html.
Like
the
Nox
SIP
Call,
in
CAIR,
EPA
authorizes,
and
fully
expects,
the
States
to
comply
with
the
emissions
reduction
requirements
through
implementation
of
a
cap­
and­
trade
program.

The
success
of
the
Acid
Rain
and
Nox
SIP
Call
cap­
and­
trade
programs
for
utility
SO2
and
Nox
emissions,
respectively,
which
EPA
duplicated
in
large
measure
with
the
CAIR
capand
trade
programs,
leads
EPA
to
conclude
that
a
cap­
and­
trade
program
for
Hg
emissions
from
utilities
qualifies
as
the
"
best
system
of
emission
reductions"
that
"
has
been
adequately
demonstrated."
A
market
system
that
employs
a
fixed
tonnage
limitation
(
or
cap)
for
Hg
sources
from
the
power
sector
provides
the
greatest
certainty
that
a
specific
level
of
emissions
will
be
attained
and
maintained
because
a
predetermined
level
of
reductions
is
ensured.
The
EPA
will
administer
a
Hg
trading
program
and
will
require
the
use
of
monitoring
to
allow
both
EPA
and
sources
to
track
progress,
ensure
compliance,
and
provide
credibility
to
the
trading
component
of
the
program.
The
benefits
of
the
cap­
and­
trade
program
are
further
described
elsewhere
in
today's
notice
and
in
the
separate
Federal
Register
notice
announcing
EPA's
revision
of
its
9­
271
December
2000
regulatory
determination
and
removing
Utility
Units
from
the
112(
c)
list
of
categories.

EPA
agrees
that
section
111(
d),
by
relying
on
the
Federal­
state
partnership,
appears
to
incorporate
the
flexibility
in
type
of
acceptable
State
plan
that
is
acceptable
for
purposes
of
section
110.
The
acceptability
of
cap­
and­
trade
programs
for
section
110
SIP
planning
purposes
suggests
that
they
should
be
acceptable
for
section
111(
d)
state
planning
purposes.

EPA
agrees
that
the
statutory
provisions
that
define
"
standard
of
performance"
are
silent
on
whether
such
standard
applies
on
a
unit­
by­
unit,
facility­
by­
facility,
or
other
basis;
and
are
silent
on
whether
the
regulated
entity
must
achieve
specific
reductions
levels
continuously,
on
an
average
basis,
or
on
some
other
basis.
Because
the
provisions
are
silent,
EPA
has
authority
to
apply
a
reasonable
interpretation,
and
EPA
considers
the
cap­
and­
trade
program
to
be
reasonable.

EPA
further
agrees
that
no
provision
of
section
111(
d)
by
its
terms,
nor
any
statements
in
the
accompanying
legislative
history,
suggest
that
a
technological
requirement,
or
any
other
specific
requirement
that
is
in
the
nature
of
a
command­
and­
control
requirement,
must
apply
to
each
individual
existing
unit.
EPA
further
agrees
that
statements
in
the
legislative
history
emphasize
the
flexibility
that
States
were
to
be
accorded
in
fashioning
plans
for
individual
sources
or
groups
of
sources.
H.
R.
Rep.
No.
95­
294
at
195,
reprinted
in
Legislative
History
of
the
Clean
Air
Act
Amendments
of
1977
at
2662
(
each
state
is
to
develop
a
"
plan"
that
should
"
be
based
on
the
best
available
means
(
not
necessarily
technological)
for
categories
of
existing
sources
to
reduce
emissions;"
EPA
is
to
"
establish
guidelines
as
to
what
the
best
system
is
for
each
[
category
of
sources];"
states
"
are
responsible
for
determining
the
applicability
of
[
the]
guidelines
to
any
particular
source
or
sources").

EPA
further
agrees
that
a
cap­
and­
trade
program
is
a
mechanism
for
taking
into
account
remaining
useful
life
of
the
existing
sources
because
it
offers
existing
sources
the
opportunity
to
comply
with
requirements
through
the
purchase
of
allowances,
and
that
the
consistency
of
a
capand
trade
program
with
the
section
111(
d)
requirements
lends
further
support
for
the
reasonableness
of
interpreting
the
term
"
standard
of
performance"
to
authorize
a
cap­
and­
trade
program.

EPA
further
agrees
that
statements
in
the
1990
legislative
history
describing
the
repeal
of
the
percentage
reduction
requirements
as
designed
to
enhance
flexibility
offer
further
support
for
EPA's
interpretation
of
section
111(
d)
to
allow
a
cap­
and­
trade
program.
E.
g.,
Senate
Debate
on
the
Clean
Air
Act
Amendments
of
1990
Conference
Report,
reprinted
in
1
Legislative
History
of
the
Clean
Air
Act
Amendments
of
1990,
at
1149
(
statement
of
Sen.
Simpson).

Comment
Four
commenters
(
OAR­
2002­
0056­
2359,
­
2823,
­
2920,
­
3459)
contended
that
even
if
the
regulation
of
HAP
were
available
under
111(
d),
EPA's
proposal
under
section
111(
d)
is
not
9­
272
an
adequate
substitute
for
section
112
regulation.
EPA
acted
arbitrarily
and
capriciously
in
implying
that
section
111
regulation,
including
a
cap
and
trade
approach,
is
adequate
to
address
the
harmful
regional
and
local
health
and
ecological
impacts
of
HAP
emissions
from
power
plants
(
2823).

Response
EPA
disagrees
with
commenters'
view
that
the
Title
IV
and
Nox
SIP
Call
programs
do
not
provide
useful
precedent
for
a
cap­
and­
trade
program
because,
according
to
commenters
those
programs
operated
against
a
backdrop
of
other
requirements
for
local
controls,
including
SIP
measures,
NSPS
provisions,
and
NSR
requirements.
EPA
believes
that
the
commenters
are
incorrect
because
many
existing
sources
subject
to
Title
IV
or
the
Nox
SIP
Call
are
not
subject
to
other
control
requirements
(
because,
for
example,
they
were
in
existence
before
the
promulgation
of
otherwise
applicable
NSPS
rules,
they
are
in
attainment
areas
and
thereby
avoid
nonattainment
SIP
requirements,
and
they
have
not
taken
actions
that
would
subject
themselves
to
PSD
requirements).
In
any
event,
the
utility
of
the
Title
IV
and
Nox
SIP
Call
programs
is
that
they
demonstrated
that
their
cap­
and­
trade
programs
succeeded
in
costeffective
achieving
reductions
.
EPA
acknowledges
commenters'
views
that
in
some
instances,
the
cap­
and­
trade
program
may
be
associated
with
increased
emissions,
or,
at
least,
emissions
levels
that
stay
constant,
in
a
particular
location
or
state.
EPA
modeled
the
effect
of
the
cap­
and­
trade
program
on
mercury
emissions.
The
section
112
revision
notice
and
accompanying
documents
describe
the
results,
including
the
lack
of
"
hot
spots."

Comment:

One
commenter
(
OAR­
2002­
0056­
5570),
responded
to
EPA's
request
for
more
information
on
the
types
of
fish
Americans
eat
and
the
concentrations
of
Hg
found
in
these
fish,
the
location
where
these
fish
are
caught,
and
the
types,
amounts,
location
and
Hg
levels
in
fish
consumed
by
highly
exposed
populations,
the
commenter
would
like
to
reiterate
their
previous
point
that
relevant
analysis
has
already
been
done
and
that
EPA
should
utilize
their
own
existing
estimates
for
fish
consumption
patterns
and
vulnerable
populations.
Most
notably,
in
preparation
for
the
new
joint
EPA/
FDA
advisory
on
Hg
in
fish,
both
Agencies
undertook
an
evaluation
of
consumption
patterns,
locations
and
vulnerable
populations.
In
addition,
external
partners
including
a
number
of
states
and
environmental
and
public
health
organizations
have
also
tracked
such
data.
Across
all
of
these
analyses,
there
is
broad
consensus
about
the
pervasiveness
of
Hg
contamination,
and
the
high
number
of
states
with
fish
advisories
for
Hg.

In
addition,
the
commenter
would
like
to
affirm
EPA's
apparent
intent
to
look
at
susceptible
populations
(
i.
e.,
the
tails
of
the
fish
consumption
distribution,
not
just
the
average)
to
ensure
that
all
Americans
are
adequately
protected.

Response:
9­
273
EPA
appreciates
the
input
from
the
commenter.
We
have
carefully
studied
fish
consumption
patterns
and
our
analysis
is
presented
in
the
RIA
and
in
the
Effectiveness
TSD.

Comment:

One
commenter
(
OAR­
2002­
0056­
5477)
stated
that
recent
scientific
studies
have
confirmed
the
serious
health
risks
to
the
developing
fetus
from
MeHg
exposure.
In
addition,
recent
studies
confirm
that
a
greater
amount
of
MeHg
is
distributed
to
the
fetus
than
previously
estimated,
leading
to
a
doubling
of
an
earlier
annual
estimate
of
newborn
infants
at
risk
in
the
U.
S.
from
300,000
to
600,000.
In
the
Northeast,
the
prospect
of
over
84,000
newborns
per
year
potentially
at­
risk
for
irreversible
neurological
deficits
and
cardiovascular
abnormalities
from
MeHg
exposure
represents
one
of
the
most
critical
public
health
threats
in
our
region
today.

Over
15,000
fish
samples
collected
in
the
Northeast
region
confirm
widespread
Hg
contamination
of
our
aquatic
ecosystems,
irreparably
threatening
human
health
and
wildlife
unless
actions
are
taken
to
reduce
significant
sources
of
Hg
emissions.
All
Northeast
states
have
issued
fish
consumption
advisories
because
of
Hg
contamination.
In
addition
to
the
toll
on
human
health
and
wildlife,
Hg
contamination
also
threatens
the
tourist
and
recreational
fishing
industries,
which
contribute
$
3
billion
a
year
to
our
regional
economy.

Recent
scientific
field
studies
have
shown
that
reductions
in
Hg
emissions
lead
to
reductions
in
the
Hg
concentrations
in
fish
tissue.
After
several
years
of
implementing
effective
regulations
to
control
Hg
emissions
from
municipal
waste
combustors,
medical
waste
incinerators,
and
other
sources
in
the
Northeast,
the
electric
utility
steam
generating
units
(
EGUs)
remain
the
largest
uncontrolled
source
category
of
Hg
and
other
hazardous
air
pollutant
(
HAP)
emissions
in
the
region.
Further,
transported
Hg
emissions
from
out­
of­
region
coal­
fired
EGUs
are
a
major
contributor
to
Hg
deposition
in
the
Northeast.
In
view
of
the
public
health
and
environmental
impacts
associated
with
exposure
to
Hg
and
other
hazardous
pollutants,
the
commenter
believed
it
was
extremely
important
that
the
EPA
take
swift
and
aggressive
steps
to
reduce
emissions
of
these
pollutants
from
EGUs
burning
coal
and
oil.

Response:

We
have
carefully
studied
fish
consumption
patterns
and
our
analysis
is
presented
in
the
RIA
and
in
the
Effectiveness
TSD.

Comment:

One
commenter
(
OAR­
2002­
0056­
5464)
stated
that
another
portion
of
the
NODA
on
which
EPA
has
requested
comments
is
its
proposed
revised
benefits
analysis.
The
commenter
reiterated
that
Section
112(
d)
is
clear
about
the
fact
that
MACT
should
be
a
technology­
based
approach,
with
requirements
no
less
stringent
than
what
well­
controlled
sources
are
accomplishing
(
i.
e.,
"
the
average
emission
limitation
achieved
by
the
best
performing
12
percent
of
the
existing
sources"
or
"
the
emission
control
that
is
achieved
in
practice
by
the
best
controlled
9­
274
similar
source").
Congress
did
not
intend
MACT
to
be
based
on
risk
assessment
or
cost­
benefit.
However,
to
the
extent
that
EPA
could
establish
a
more
stringent
MACT
beyond
the
floor
and
may
consider
cost­
benefit
in
doing
so,
the
commenter
offered
several
comments
to
improve
the
benefits
analysis.

The
commenter
was
concerned
that
EPA's
earlier
benefits
analysis
calculated
costs
relative
only
to
reductions
in
emissions
of
fine
particulate
matter
(
PM2.5)
and
focused
on
only
certain
health
effects.
It
did
not
include
a
comprehensive
list
of
PM2.5­
related
health
effects,
nor
did
it
cover
health
effects
related
to
Hg,
other
HAPs,
ozone,
sulfur
dioxide,
nitrogen
oxides
or
welfare
effects
related
to
Hg,
PM,
ozone,
nitrogen
and
sulfate
deposition.
While
they
were
pleased
that
EPA
plans
to
expand
its
benefits
analysis
to
include
some
of
the
health
effects
related
to
Hg,
they
did
not
believe
it
will
go
far
enough.
For
example,
the
benefits
analysis
will
include
studies
related
to
the
effects
of
Hg
exposure
on
IQ,
but
it
will
not
adequately
consider
the
cardiovascular
health
effects.
There
are
emerging
data
and
well­
developed
studies
showing
an
increase
in
death
from
heart
attacks
in
men
following
Hg
exposure.
Furthermore,
in
considering
IQ,
EPA's
analysis
examines
only
decreased
income
resulting
from
lowered
IQ
and
does
not
consider
costs
related
to
therapy,
tutoring,
special
education
and
other
remedial
efforts.

Due
to
the
commenter's
concern
that
even
the
revised
benefits
analysis
will
underestimate
the
benefits
of
Hg
reduction
programs,
they
recommend
that
the
benefits
analysis
be
much
more
comprehensive
and
inclusive.
Where
quantitative
data
related
to
benefits
are
not
available,
the
multiple
benefits
of
additional
Hg
controls
should
be
evaluated
qualitatively
and
given
weight
in
determining
MACT
limits
that
are
more
stringent
than
the
MACT
floor.

The
commenter
was
concerned
that
the
proposed
definition
of
a
hot
spot
indicates
that
the
plant
must
cause
exposures
above
the
RID
and
believed
this
was
inadequate.
As
suggested
by
the
National
Academy
of
Sciences
panel
that
considered
the
health
effects
of
MeHg,
and
further
supported
by
more
recent
research,
the
dose­
response
to
Hg
appears
to
be
linear
and
effects
have
been
reported
at
doses
below
the
RID.
It
seems,
therefore,
that
the
definition
of
"
hot
spot"
should
not
rely
upon
the
RID.

Given
the
uncertainty
that
EPA
has
admitted
relative
to
its
modeling,
the
commenter
felt
the
agency
could
not
offer
assurances
about
its
calculations
of
the
contributions
of
individual
plants.
When
added
to
questions
about
health
effects
below
the
current
RID,
the
commenter
believed
EPA's
definition
of
hot
spots
in
the
proposal
is
inappropriate
and
does
not
protect
public
health.

Response:

EPA
appreciates
the
input.
Please
see
the
RIA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5422)
noted
that
EPA
has
requested
comments
as
to
9­
275
how
reductions
in
population­
level
exposures
of
Hg
will
improve
public
health.
The
commenter
stated
that
it
was
important
to
understand
that
there
is
a
threshold
for
Hg
levels
in
the
blood
below
which
there
are
no
effects.
This
is
in
contrast
to
lead,
which
appears
to
have
no
clear
threshold
level.
Unlike
lead
a
significant
(>
50
percent)
percentage
of
atmospheric
Hg
is
from
natural
sources.
Mercury
has
been
present
in
fish
tissue
prior
to
the
industrial
revolution.
EPA
has
selected
an
RfD
for
Hg
in
maternal
blood
(
5.8
ppb)
that
serves
as
a
de­
facto
threshold.
This
number,
which
is
10
times
below
the
threshold
number
developed
from
the
Faroe
Islands
study
and
14
times
lower
than
the
WHO
level
of
concern,
is
very
conservative.
If
an
unrealistically
low
threshold
(
ULT)
for
Hg
blood
levels
were
used
to
estimate
benefits,
reductions
in
blood
levels
between
the
true
threshold
and
the
ULT
would
create
the
appearance
of
a
benefit
where
there
is
none.

EPA
has
requested
comments
as
to
the
appropriateness
of
using
IQ
as
an
endpoint
for
both
quantifying
neurological
development
and
the
benefit
analysis
for
reduced
exposure
to
MeHg.
In
addition,
EPA
requested
comments
on
the
appropriateness
of
a
linear
dose
response
model
evaluating
health
impacts.
There
is
a
concern
that
EPA
may
wish
to
develop
a
relationship
between
Hg
emissions
and
general
population
IQ.
If
this
relationship
were
then
coupled
with
an
imputed
value
for
increased
IQ
for
the
general
population,
large
estimated
benefits
could
be
generated
that
would
not
exist,
since
there
is
no
evidence
of
IQ
impact
at
blood
Hg
levels
greater
than
the
RfD
but
below
the
Faroe
Island
threshold
level.
There
are
opportunities
to
calculate
an
imputed
value
for
IQ
changes,
for
example,
recent
work
by
Jones
and
Schneider
estimates
that
a
1
point
increase
in
national
IQ
is
associated
with
a
0.16
percent
annual
increase
in
GNP.
There
is
also
a
concern
that
assuming
a
linear
response
between
blood
Hg
and
IQ
would
lead
to
an
imputed
benefit
for
reducing
blood
Hg
below
the
threshold
level,
again
creating
benefits
that
do
not
exist.

EPA's
successful
lead
reduction
program
is
not
an
appropriate
model
for
Hg.
Lead
is
a
pollutant
that
has
been
linked
to
neurological
damage
similar
to
that
of
Hg.
In
the
late
1970s,
EPA
initiated
a
successful
program
designed
to
eliminate
all
lead
emissions
into
the
environment
primarily
through
the
phase­
out
of
leaded
gasoline.
Since
airborne
lead
emissions
are
linked
to
blood
lead
levels
in
children
and
related
neurological
impacts,
it
may
appear
reasonable
to
utilize
the
lead
elimination
model
for
dealing
with
Hg.
However,
there
are
important
reasons
why
the
program
to
reduce
lead
(
total
elimination
of
air
emissions)
is
not
appropriate
for
dealing
with
Hg.

°
Virtually
all
airborne
lead
is
attributed
to
anthropogenic
sources
while
a
large
percentage
of
airborne
Hg
(>
50
percent)
is
due
to
natural
sources.
It
is
impossible
to
eliminate
all
airborne
Hg
emissions.

°
Lead
emissions
and
ambient
lead
concentrations
are
primarily
associated
with
urban
areas
while
Hg
emissions
and
ambient
Hg
concentration
are
global.

°
While
there
appears
to
be
no
lower
limit
for
neurological
impacts
for
lead
blood
levels,
Hg
blood
levels
have
a
clear
threshold
below
which
there
are
no
neurological
impacts.
9­
276
°
While
neurological
impacts
were
clearly
shown
at
blood
lead
levels
present
in
urban
US
children
in
the
1970s,
no
such
neurological
impacts
have
been
noted
or
documented
at
Hg
blood
levels
currently
found
in
American
child­
bearing
age
women
or
children.

Response:

EPA
appreciates
the
input.
Please
see
the
RIA.

Comment:

One
commenter
(
OAR­
2002­
0056­
5477)
stated
that
in
its
NODA,
EPA
notes
that
it
had
included
a
benefits
assessment
in
its
earlier
proposed
CAMR.
The
commenter
would
like
to
note
that
EPA's
benefits
assessment
was
inadequate
for
the
important
issue
of
establishing
"
Beyond­
the­
floor
MACT."
EPA
goes
on
to
state
that
it
has
"
preliminarily
revised
its
proposed
approach
to
analyzing
the
benefits
associated
with
Hg
emission
reductions
from
power
plants."
In
our
earlier
comments,
the
commenter
did
not
propose
a
methodology
for
benefits
assessment.
Since
then
the
commenter
ha
completed
an
extensive
and
comprehensive
draft
report
"
Estimating
Reductions
in
U.
S.
Mercury
Exposures
from
Decreased
Power
Plant
Emissions
and
the
Associated
Economic
Benefit,"
that
is
undergoing
an
intensive
peer
review.
The
extensive
scientific
work
that
forms
the
basis
of
this
report
was
undertaken
by
the
commenter
with
Harvard
Center
for
Risk
Analysis
(
HCRA),
part
of
the
Harvard
School
of
Public
Health
(
HSPH).

The
report
was
prepared
by
Glenn
Rice
of
HSPH
as
part
of
his
doctoral
work
under
the
direction
of
Dr.
James
Hammitt,
Director,
Harvard
Center
for
Risk
Analysis.
The
report
covers
diverse
areas
of
research,
including:
Hg
emissions
from
sources,
atmospheric
transport
and
fate
of
Hg,
atmospheric
modeling
and
estimation
of
Hg
deposition,
relationship
between
Hg
deposition
and
MeHg
levels
in
fish
(
and
how
they
change
with
changes
in
emissions),
current
and
future
exposures
of
humans
to
Hg
in
fish,
dose
response
functions,
and
finally,
the
monetization
of
the
benefits
related
to
reduced
Hg
emissions
from
coal­
fired
power
plants.
The
report
evaluates
these
effects
in
four
sequential
tasks:

Task
1:
Estimation
of
the
effect
of
a
specified
reduction
in
power
plant
emissions
of
Hg
on
changes
in
regional
Hg
deposition
and
the
resulting
concentrations
of
MeHg
in
fish.

Task
2:
Estimation
of
the
effect
of
changes
in
MeHg
concentrations
in
fish
on
human
uptake.

Task
3:
Estimation
of
the
effect
of
changes
in
human
uptake
on
the
incidence
of
adverse
human
health
effects.

Task
4:
Quantification
of
the
"
monetized"
value
of
the
change
in
incidence
of
health
effects.

Some
of
the
benefits
of
controlling
Hg
are
monetized
for
two
Hg
control
scenarios.
These
9­
277
are
based
on
Clear
Skies
Initiative
(
CSI)
Phase
I,
2010
(
26
TPY
cap)
and
Phase
II,
2020
(
15
TPY
cap).
The
Hg
deposition
levels
for
the
base
case
(
2001),
as
well
as
two
pairs
of
base
case/
control
case
scenarios
(
Phase
I
and
Phase
II)
were
developed
by
the
EPA
using
the
REMSAD
model
as
part
of
the
Agency's
analysis
of
the
Clear
Skies
Initiative.
The
commenter's
analysis
estimated
two
sets
of
monetized
benefits
(
for
Scenario
1
and
Scenario
2)
which
are
based
on
comparing
the
control
case
and
base
case
deposition
levels
for
CSI
Phase
I
and
for
Phase
II.
The
Hg
emission
estimates
for
the
base
case
as
well
as
for
four
future
scenarios
were
also
provided
by
EPA,
based
on
IPM
outputs.

The
commenter's
analysis
evaluated
the
effect
of
changes
in
Hg
emissions
assuming
no
changes
in
the
population
or
dietary
patterns
of
U.
S.
residents.
For
this
reason,
the
results
are
best
interpreted
as
an
estimate
of
the
benefits
of
lower
Hg
emissions
in
a
steady­
state
world
with
population
and
fish
consumption
patterns
similar
to
current
conditions.
To
estimate
the
benefits
of
reduced
Hg
emissions
in
future
years
would
require
projecting
changes
in
human
population,
fish
harvesting
and
consumption,
the
temporal
relationship
between
changes
in
Hg
emissions
from
power
plants
and
levels
of
MeHg
in
fish,
and
other
factors.

To
account
for
the
effects
of
changes
in
Hg
deposition
on
MeHg
levels
in
fish,
the
U.
S.
landmass
was
divided
into
five
regions
(
West,
Midwest,
Mid
Atlantic,
Southeast,
and
Northeast).
Additionally,
the
surrounding
waters
were
studied
as
three
regions
for
commercial
and
non
commercial
fish
(
Gulf,
Atlantic,
and
"
all
other
marine
waters.").
Estimates
of
human
uptake
of
MeHg
through
fish
consumption
are
based
on
regional
patterns
of
consumption
of
fish
species,
both
commercial
and
non­
commercial.

The
report
integrates
the
avoided
costs
(
or
"
benefits")
for
two
endpoints
associated
with
a
reduction
in
the
neurological
effects
that
result
from
intrauterine
MeHg
exposures
and
with
reductions
in
adult
fatal
and
non­
fatal
cardiovascular
(
myocardial)
events
related
to
adult
MeHg
exposures.
The
effects
of
MeHg
intake
on
myocardial
events
are
less
certain
than
the
effects
on
neurological
events.
The
neurological
benefits
were
valued
using
a
cost­
of­
illness
model
based
on
IQ­
point
gains
that
could
result
from
decreased
MeHg
exposures.
The
non­
fatal
myocardial
events
were
valued
using
a
cost­
of­
illness
approach.
The
premature
mortality
events
were
valued
using
a
willingness­
to­
pay
or
value­
of­
statistical­
life
approach.

These
neurological
effects
and
the
fatal
and
non­
fatal
cardiovascular
effects
likely
account
for
a
large
fraction
of
the
total
monetary
value
of
damage
to
humans
that
is
associated
with
MeHg
exposures.
The
study
also
discusses
two
additional
effects
that
have
been
observed
in
children
and
associated
with
intrauterine
MeHg
exposures:
increased
blood
pressure
and
decreased
heart
rate
variability.
However,
the
study
does
not
quantify
these
risks,
because
the
increased
blood
pressure
does
not
appear
to
persist
and
the
clinical
significance
of
changes
in
heart
rate
variability
of
otherwise
healthy
children
is
not
known.

Based
on
the
preliminary
results
of
the
detailed
analysis,
benefits
for
Scenario
1
(
26
TPY
cap)
associated
with
improved
IQ
range
from
$
64
million
(
assuming
a
neurotoxicity
threshold
equal
to
the
RfD)
to
$
160
million
(
assuming
no
threshold).
The
corresponding
benefits
for
9­
278
Scenario
2
(
15
TPY
cap)
are
$
93
million
to
$
230
million.
Much
larger
benefits
are
associated
with
avoided
cardiovascular
events
(
fatal
and
non­
fatal).
For
Scenario
1,
the
monetized
benefits
are
$
2.7
billion.
The
corresponding
benefits
for
Scenario
2
are
$
3.8
billion.
All
of
these
monetized
benefits
are
per
year.
The
total
annual
benefits
for
the
two
endpoints
studied
range
from
$
2.8
billion
for
Scenario
1
to
just
over
$
4
billion
for
Scenario
2.

It
is
important
to
note
that
there
is
considerable
uncertainty
in
the
analysis
and
this
includes
a
difference
in
the
degree
of
confidence
in
the
underlying
studies
for
MeHg
neurotoxicity
(
based
on
the
various
"
islands"
studies)
and
the
studies
related
to
effects
of
MeHg
on
the
cardiovascular
system.
The
neurological
effects
associated
with
in
utero
MeHg
exposures
are
well
documented
and
have
been
thoroughly
evaluated
by
a
number
of
research
and
advisory
groups
(
e.
g.,
National
Research
Council,
2000).
However,
the
current
published
literature
providing
evidence
for
evaluating
the
association
between
cardiovascular
events
with
adult
MeHg
exposures
is
substantially
smaller
and
more
recent
than
that
for
the
neurotoxic
events.

It
is
also
important
to
note
that
the
commenter's
study
did
not
evaluate
monetized
benefits
associated
with
EPA's
proposed
MACT
approach
under
Section
112
or
EPA's
preferred
approach
of
performance
standards
under
Section
111
of
the
Clean
Air
Act
or
other
more
stringent
and
technologically
feasible
control
levels
(
for
example,
less
stringent
of
90
percent
control
(
from
Hg
in
coal)
or
0.6
lb/
TBTU,
as
proposed
by
the
States
Stakeholders,
(
see
Appendix
A,
Page
10­
16,
see
OAR­
2002­
0056­
5477)
since
EPA
did
not
undertake
modeling
of
these
scenarios
with
IPM
and
REMSAD/
CMAQ
modeling.
However,
it
should
be
obvious
to
EPA
that
monetized
benefits
would
be
substantially
higher
for
the
proposal
offered
by
the
States
Stakeholders
for
only
a
small
increase
in
costs
(
based
on
application
of
extremely
cost­
effective
and
commercially
available
technologies
such
as
ACI).
Thus,
The
commenter
stood
by
their
previous
comments
in
support
of
a
90
percent
reduction
in
Hg
emissions
from
coal­
fired
EGUs.

Response:

EPA
appreciates
the
commenters
input.
Due
to
the
summary
nature
of
the
information
provided,
EPA
was
not
able
to
fully
evaluate
the
analysis
and
its
inputs
and
therefore
was
not
in
a
position
to
incorporate
the
analysis
summary
or
conclusions.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
points
out
that,
as
shown
in
comment
(
O),
EPA's
premise
for
negative
child
neurodevelopment
is
based
essentially
on
one
endpoint
from
the
Faroe
Island
study
that
is
representative
of
exposure
to
a
cocktail
of
toxic
chemicals
like
PCBs,
DDT
and
MeHg
rather
than
MeHg
alone
as
demanded
by
EPA's
CAMR
power
plant
emission
controls.
This
commenter
suggests
that
EPA's
claim
for
health
"
benefits"
from
its
CAMR
is
hypothetical
or
almost
impossible
to
demonstrate
because
the
suggested
health
concerns
were
drawn
on
either
flawed
or
irrelevant
epidemiological
data.

In
direct
contrast
to
claims
of
health
concerns
from
consuming
fish
with
trace
amounts
of
9­
279
MeHg,
this
commenter
offers
findings
from
recent
scientific
studies
supporting
claims
of
significant
children
health­
related
benefits
derived
through
adequate
consumption
of
fish
or
fish
oil
containing
omega­
3
polyunsaturated
fatty
acids.

Helland
et.
al.,
(
2003,
Pediatrics,
vol.
111,
e39­
e44)
recently
stated
that:

"
Pregnant
women
[
of
Oslo,
Norway]
were
recruited
in
week
18
of
pregnancy
to
take
10
mL
of
cod
liver
oil
[
with
about
2g
of
DHA+
EPA]
or
corn
oil
until
3
months
after
delivery
[
in
a
randomized
and
double­
blinded
study].
Children
who
were
born
to
mothers
who
had
taken
cod
liver
oil
(
n=
48)
during
pregnancy
and
lactation
scored
higher
[
by
4
points]
on
the
Mental
Processing
Composite
of
the
K­
ABC
[
Kaufman
Assessment
Battery
for
Children]
at
4
years
of
age
as
compared
with
children
whose
mothers
had
taken
corn
oil.
This
study
indicates
that
maternal
supplementation
with
very­
long­
chain
n­
3
PUFAs
during
pregnancy
and
lactation
improves
the
intelligence
of
children
at
4
years
of
age."

Daniels
et
al.
(
2004,
Epidemiology,
15,394­
402)
found
that:

"
Fish
intake
by
mother
during
pregnancy
and
by
the
infant
postnatally,
was
associated
with
higher
mean
[
child]
development
scores
[
in
a
cohort
of
7421
British
children].
For
example,
the
adjusted
mean
MacArthur
[
vocabulary]
comprehension
score
for
children
[
15
months
old]
whose
mothers
consumed
fish
four
or
more
times
per
week
was
72
compared
with
68
among
those
whose
mothers
did
not
consume
fish.
Although
total
cord
mercury
levels
increased
with
maternal
fish
intake,
our
data
did
not
suggest
adverse
developmental
effects
associated
with
mercury.
In
a
small
study
of
subjects
in
[
this]
ALSPAC
study,
maternal
DHA
levels
were
associated
with
improved
visual
stereo
acuity
among
offspring
at
3.5
years
of
age.
Fish
intake
during
pregnancy
has
the
potential
to
improve
fetal
development
because
it
is
a
good
source
of
iron
and
long
chain
omega
fatty
acids,
which
are
necessary
for
proper
development
and
function
of
the
nervous
system."

Finally,
in
another
new
study,
Smuts
et
al.
(
2003,
Obstetrics
and
Gynecology,
vol.
101,469­
479)
explains:

"[
Our]
study
was
a
randomized,
double­
blind,
controlled,
clinical
trial
to
determine
the
effects
of
increasing
docosahexaenoic
[
DHA]
acid
intake
during
the
third
trimester
of
pregnancy
on
pregnancy
and
birth
outcomes.
Subjects
were
supplied
with
[
DHA­]
enriched
eggs
(
mean
of
133
mg
of
[
DHA]
per
egg)
or
ordinary
eggs
(
mean
of
33
mg
of
[
DHA]
per
egg).
Eighty­
three
percent
of
subjects
completed
the
study
(
291
of
350
enrolled).
No
subject
was
discontinued
for
an
adverse
event.
No
safety
concerns
were
raised
by
the
study.
The
current
study
found
a
6­
day
longer
period
of
gestation
when
[
DHA]
intake
was
increased
...
Olsen
et
al.
suggested
that
higher
[
DHA+
EPA]
intake
from
fish
by
Faroe
Islanders
compared
9­
280
with
Danes
was
the
reason
for
longer
gestation
in
Faroe
Islanders.
The
authors
subsequently
demonstrated
increases
in
gestation
of
4
and
8.5
days,
respectively,
in
randomized
clinical
trials
that
provided
2.7
g
per
day
of
[
DHA+
EPA]
to
a
group
of
healthy
pregnant
women
and
to
healthy
pregnant
women
with
a
previous
pre­
term
delivery."

The
commenter
notes
that
claims
of
concern
for
fetal
and
child
health
by
EPA
and
Hg
activists
appear
disingenuous
because
they
largely
failed
to
emphasize
to
the
public
the
benefits
of
fish
consumption.
This
activism
could
unnecessarily
terrorize
expectant
mothers
into
not
eating
a
food
that
promotes
better
fetal
development
and
child
health.

Premature
birth
is
a
striking
example.
So
serious
is
this
outcome
that
the
March
of
Dimes
organization
has
adopted
it
as
a
primary
cause.
More
than
470,000
babies
are
born
prematurely
every
year
in
the
U.
S.
These
infants
aren't
just
small;
they're
developmentally
"
unfinished."

The
March
of
Dimes
provides
these
facts
on
prematurely
born
babies:

°
Has
increased
by
29
percent
since
1981
°
Accounts
for
12
percent
of
all
live
births
°
Can
happen
to
any
pregnant
woman
°
Is
the
leading
killer
of
babies
in
their
first
month
of
life
°
Is
a
major
cause
of
long­
term
health
problems,
including
cerebral
palsy,
mental
retardation,
blindness,
chronic
lung
problems,
Respiratory
distress
syndrome
and
bleeding
in
the
brain
°
Is
the
number
one
obstetrical
problem
in
the
country
°
Robs
families
of
the
full
potential
of
their
children,
society
of
their
future
leaders
and
our
nation
of
strong
and
healthy
citizens
°
Places
tremendous
financial
burdens
on
everyone.
Hospital
charges
for
infants
with
a
principle
diagnosis
of
prematurely
average
$
75,000,
and
add
up
to
billions
of
dollars
each
year.

Recognizing
the
role
of
fish
nutrition
plays
in
helping
prevent
the
tragedy
of
premature
births,
the
March
of
Dimes
is
funding
a
Danish
and
Chinese
research
team
to
further
clarify
the
issue.
One
of
the
researchers,
Dr.
Sjurdur
Olsen
of
Denmark
reported
that
Danish
women
who
consumed
fish
or
seafood
at
least
once
a
week
during
the
first
16
weeks
of
pregnancy
have
three
times
less
risk
of
low­
birth
weight
or
premature
births.
But
a
closer
look
at
the
literature
will
reveal
ample
evidence
already
available
that
women
who
avoid
fish
in
their
diets
during
pregnancy
are
at
increased
risk
for
delivering
their
babies
early,
which
increases
risk
for
their
babies
being
born
small,
sick
and
dying.

Response:

The
US
Government
emphasizes
that
fish
and
shellfish
are
an
important
part
of
a
healthy
diet
for
women
and
young
children;
and
that
women
and
young
children
should
include
fish
or
9­
281
shellfish
in
their
diets
due
to
the
many
nutritional
benefits.
Recommendations
for
selecting
and
eating
fish
or
shellfish
are
made
by
EPA
and
FDA.
These
recommendations,
if
followed,
should
enable
women
and
young
children
to
receive
the
benefits
of
eating
fish
and
shellfish
and,
at
the
same
time,
they
can
be
confident
that
they
have
minimized
their
exposure
to
the
harmful
effects
of
mercury.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
notes
that
the
postulated
but
unconfirmed
effects
of
MeHg
on
cardiovascular
health
in
the
NRC
(
2000)
report
appear
to
have
contributed
to
EPA's
RfD
for
MeHg.

Alan
Stern,
of
the
New
Jersey
Department
of
Environmental
Protection
and
member
of
the
NRC
(
2000)
MeHg
committee,
recently
revealed:

"
In
2000,
the
National
Research
Council's
Committee
on
the
Toxicological
Effects
of
Methylmercury
issued
a
report
(
NRC,
2000)
in
which
it
considered
the
various
adverse
health
effects
associated
with
the
exposure
to
methylmercury
(
MeHg).
Among
the
effects
considered
were
cardiovascular
effects.
The
committee
concluded
that
`
Given
the
limits
of
the
available
data,
neurotoxicity
is
the
most
sensitive,
well­
documented
health
endpoints.
However,
there
is
emerging
evidence
of
potential
effects
on
both
the
immune
and
cardiovascular
systems
at
low
doses
of
exposure.
Although
these
effects
are
not
well
understood,
emerging
data
underscore
the
need
for
continued
research
and
raise
the
possibility
of
adverse
effects
...
at
or
below
the
current
levels
of
concern
for
developmental
neurotoxicity.'
The
committee
recommended
that
an
overall
uncertainty
factor
of
adjustment
of
10
be
applied
to
the
neurodevelopmental
point
of
departure
to
derive
a
MeHg
reference
dose
(
RfD).
This
uncertainty
factor,
in
part,
addressed
the
possibility
that
cardiovascular
effects
may
ultimately
prove
to
be
a
more
sensitive
endpoint
than
neurodevelopment
effects.
The
US
EPA,
in
its
derivation
of
an
RfD
for
methylmercury,
followed
the
lead
of
the
NRC
committee
in
applying
a
similar
rationale
for
its
10­
fold
uncertainty
factor
adjustment
(
US
EPA
2004)."

The
commenter
suggests
that
EPA
should
be
more
critical
in
providing
an
independent
assessment
on
this
potentially
dangerous
and
poorly
documented
claim.
To
that
end,
the
commenter
offers
several
concise
criticisms
on
the
two
main
published
studies
(
as
cited
by
EPA's
NODA)
suggesting
a
connection
between
MeHg
exposure
from
fish
and
cardiovascular
disease
(
CVD),
coronary
health
disease
(
CHD)
and
even
death
in
adults.
(
A
longer
and
more
thorough
review
on
this
recent
alarmism
about
the
negative
impacts
of
fish
intake
on
cardiac
health
can
be
found
in
"
Fish,
Mercury
and
Cardiac
Health"
by
CSPP.)
But
it
should
be
pointed
out
that
the
third
study
cited
by
the
EPA's
NODA,
the
Yoshizawa
et
al.
(
2002,
New
England
Journal
of
Medicine,
vol.
347,
1755­
1760)
paper,
actually
reported
their
inability
to
confirm
an
association
of
total
Hg
exposure
and
risk
of
CVD
based
on
a
5­
year
follow­
up
of
33,737
U.
S.
male
health
professionals.
The
results
of
Yoshizawa
et
al.
(
2002)
clearly
did
not
raise
the
"
possibility
that
9­
282
MeHg
in
fish
can
reduce
the
cardio­
protective
effects
of
fish
consumption
in
adult
males"
as
incorrectly
implied
by
EPA's
citation.

First,
the
commenter
provides
some
background
on
the
two
studies
claiming
negative
cardiac
health
associations
with
fish
consumption.

(
1)
The
Finnish
Study
by
Salonen
et
al.
(
1995,
Circulation,
vol.
91,645­
655;
2000,
Atherosclerosis,
vol.
148,265­
273)
and
Virtanen
et.
al.,
(
2002,
poster
presentation
in
the
April
23­
26,
2002
American
Heart
Association,
Asia
Pacific
Scientific
Forum
at
Honolulu,
Hawaii):
A
study
of
2005
men
from
Kuopio,
eastern
Finland
found
that
men
in
the
highest
quarter
(>
2.5
ppm)
had
a
1.6­
fold
risk
of
CVD
death
and
1.7­
fold
risk
of
CHD
death
when
compared
to
men
in
the
lowest
three
quarters
after
adjusting
for
numerous
risk
factors
including
age,
LDL
(
bad)
cholesterol
and
triglyceride,
intakes
of
saturated
animal
fatty
acids
and
etc.

(
2)
The
European/
Israeli
Study
by
Guallar
et.
al.,
(
2002,
New
England
Journal
of
Medicine,
vol.
347,
1747­
1754):
A
case­
control
study
of
684
men
with
724
controls
reported
increasing
toe
nail
Hg
level
from
0.11
to
0.66
ppm
(
about
0.34­
2
ppm
in
equivalent
hair
Hg
levels)
is
associated
with
a
doubling
of
the
risk
of
myocardial
infarction
after
adjusting
for
numerous
risk
factors
like
age,
family
history
of
heart
attack,
smoking
status,
alcohol
intake,
diabetes,
history
of
hypertension,
selenium
intake,
etc.

However,
as
explained
in
the
commenter's
report,
"
Fish,
Mercury
and
Cardiac
Health,"
numerous
risk
factors
other
than
MeHg
in
fish
will
more
likely
explain
most
of
the
findings
in
Salonen
et.
al.,
(
1995,
2000)
and
Guallar
et.
al.,
(
2002).

Statistics
of
mortality
from
Coronary
Heart
Disease:
Men
of
Eastern
Finland
are
especially
vulnerable
"
The
intake
of
diary
products,
potatoes,
butter,
and
sugar
products
was
very
high
in
Finland.
A
similar
but
lower
intake
pattern
was
observed
in
The
Netherlands.
Fruit,
meat
and
pastry
consumption
was
high
in
the
USA.
Cereals
and
wine
consumption
was
high
in
Italy,
while
bread
consumption
was
high
in
Yugoslavia
with
the
exception
of
the
Belgrade
cohort.
In
Greece,
the
intake
of
olive
oil
and
fruit
was
very
high,
while
the
Japanese
cohorts
were
characterized
by
a
high
consumption
of
fish,
rice,
and
soy
products."

Table
1:
Age­
standardized
25­
year
death
rates
per
1000
from
CHD
in
16
cohorts
of
the
Seven
Countries
Study.
Standard
error
of
rate
in
parenthesis.

Cohorts
N
CHD
(
death
rates/
1,
OOO)

US
Railroad,
USA
2571
160
(
7)

East
Finland,
Finland
817
268
(
15)
Cohorts
N
CHD
(
death
rates/
1,
OOO)

9­
283
West
Finland,
Finland
860
180
(
13)

Zutphen,
The
Netherlands
878
169
(
13)

Crevalcore,
Italy
993
93
(
9)

Montegiorgio,
Italy
719
60
(
9)

Rome
Railroad,
Italy
768
87
(
10)

Dalmatia,
Croatia
671
54
(
9)

Crete,
Greece
686
25
(
6)

Corfu,
Greece
529
48
(
9)

Tanushimaru,
Japan
508
30
(
8)

Ushibuka,
Japan
502
36
(
8)

Velika
Krsna,
Serbia
511
43
(
9)

Zrenjanin,
Serbia
516
116
(
14)

Belgrade,
Serbia
536
106
(
13)

Slavonia,
Croatia
696
89
(
10)

Menotti
et
al.,
1999,
European
Journal
of
Epidemiology,
vol.
15,
507­
515
The
commenter's
criticisms
on
Salonen
et.
al.,
(
1995,
2000)
include
the
following
points:

(
1)
Salonen
et.
al.,
(
1995)
own
admission:
"
Theoretically,
our
findings
could
be
specific
only
for
men
in
Eastern
Finland,
who
traditionally
have
a
high
intake
of
meat,
fish,
and
saturated
animal
fat
and
a
low
intake
of
selenium
and
vitamin
C
and,
most
likely,
other
vegetable­
derived
antioxidants."

(
2)
The
Kupio
population
has
one
of
the
highest
recorded
rates
of
CHD
and
high
consumption
of
animal
fat
with
high
measured
levels
of
LDL
(
bad)
cholesterol.

(
3)
Stern
(
2005,
Environmental
Research,
in
press)
pointed
out
that
even
in
Salonen
et
al.
(
1995)
as
long
as
9
years
already
elapsed
between
the
collection
of
hair
and
urine
samples
and
the
recording
of
a
CVD
and
CHD
and
death
event.
Updated
report
of
KIHD
Hg­
related
results
in
Virtanen
et.
al.,
(
2002)
extends
the
elapse
time
to
16
years
or
so
and
hence
contributing
to
a
serious
potential
misclassification
of
causes
and
effects.

(
4)
Clarkson
(
2002)
noted
that
highest
recorded
hair
level
is
15.7
ppm
and
more
than
6
standard
9­
284
deviations
from
the
mean
and
only
a
small
percentage
of
the
population
has
high
hair
Hg.
Yet
high­
value
points
may
playa
major
role
in
this
type
of
study,
"
it
would
have
been
of
interest
to
see
if
these
correlations
persisted
when
the
very
high
mercury
levels
were
excluded."

(
5)
No
clear
accounting
for
stress
 
which
is
believed
to
be
a
major
risk
factor.

The
commenter's
criticisms
on
Guallar
et.
al.,
(
2002)
include
the
following
points:

(
1)
Contradicted
by
the
negative
results
of
Yoshizawa
et
al.
(
2002)
5­
year
follow­
up
study
of
33.737
US
male
health
professionals
that
covers
a
wider
range
of
toenail
Hg
from
0
to
14.6
ppm
(
or
about
45
ppm
in
equivalent
hair
Hg
level)

(
2)
Why
is
LDL
cholesterol
not
measured
and
identified
as
a
risk
factor
(
while
HDL
and
total
cholesterol
were
measured)?

(
3)
Serious
challenges
and
questions
from
Plante
and
Babo
(
2003)
in
New
England
Journal
of
Medicine
(
vol.
348,
2151­
2152):
"
Patients
with
Minamata
disease
and
hair
mercury
levels
above
100
ppm
did
not
have
a
higher
rate
of
death
from
heart
disease
than
controls,
nor
did
they
have
a
higher
degree
of
arteriosclerosis.
In
the
Minamata
region
of
Japan,
a
population
of
approximately
50,000
with
an
average
hair
mercury
level
of
50
ppm
did
not
have
a
higher
rate
of
death
from
heart
disease
than
a
reference
population
of
800,000
with
an
average
level
of
9
ppm.
Cree
Indians
with
an
average
hair
mercury
concentration
of
10
ppm
have
a
lower
risk
of
death
from
circulatory
disease
than
the
rest
of
the
population
in
Quebec,
in
which
the
average
hair
mercury
level
is
0.5
ppm.
If,
as
Guallar
et.
al.,
suggest,
mercury
increases
the
risk
of
myocardial
infarction
by
more
than
100
percent
when
the
hair
mercury
level
reaches
2
ppm,
how
can
one
explain
the
absence
of
effects
at
doses
greater
than
100
ppm?"

Concerning
"
sudden
death"
the
clinical
evidence
continues
that
fish
nutrition
can
lower
the
risk:

"
The
n­
3
fatty
acids
found
in
fish
are
strongly
associated
with
a
reduced
risk
of
sudden
death
among
men
without
evidence
of
prior
cardiovascular
disease.
As
compared
with
men
with
levels
of
long­
chain
n­
3
fatty
acids
in
the
lowest
quartile,
those
with
levels
in
the
highest
quartile
had
an
81
percent
lower
risk
of
sudden
death."
(
Albert
et.
al.,
2002)

"[
W]
e
have
summarized
the
growing
clinical
evidence
that
these
n­
3
fatty
acids
are
antiarrhythmic
and
can
prevent
sudden
cardiac
death
in
humans.
These
n­
3
fatty
acids
have
been
part
of
the
human
diet
for
some
2
to
4
million
years.
They
are
safe
and
have
been
listed
on
the
GRAS
(`
generally
regarded
as
safe')
list
according
to
the
Food
and
Drug
Administration
in
amounts
up
to
3.5
g
of
fish
oil
per
day."
(
Leaf
et.
al.,
2003)

"
Alexander
Leaf
and
colleagues
suggest
a
hypothesized
cellular
mechanism
through
which
3
PUFAs
affect
ion
channels
to
reduce
the
risk
of
arrhythmia.
The
9­
285
messages
...
are
clear.
For
clinicians,
it
is
time
to
implement
the
current
American
Heart
Association
dietary
guidelines
that
recommend
the
dietary
intake
of
1
to
2
fish
meals,
particularly
fatty
fish,
each
week.
For
policymakers,
there
is
a
need
to
consider
new
indication
for
treatment
with
low­
dose
n­
3
PUFAs
supplements
..."
(
Siscovick
et.
al.,
2003)

Speaking
on
cardiac
risk
concerns,
Professor
Tom
Clarkson,
Distinguished
Professor
of
Environmental
Medicine
at
the
University
of
Rochester
has
commented
that:

"
Eating
lots
of
ocean
fish
isn't
much
of
a
hazard
compared
to
missing
out
on
the
benefits
from
not
eating
fish.
A
slew
of
scientific
reports
have
shown
that
eating
fish
helps
protect
against
cardiovascular
disease
and
enhances
brain
development
before
and
after
birth.
Fish
is
a
rich
source
of
low­
fat
protein
and
is
full
of
fatty
acids
known
to
lower
cholesterol.
Overstating
the
almost
negligible
risk
of
mercury
could
adversely
affect
millions
of
people
who
face
the
risk
of
heart
disease."

Dr.
Eric
Rimm,
Professor
of
Epidemiology
and
Nutrition
at
Harvard
School
of
Public
Health
agreed:

"
The
message
of
fish
being
good
has
been
lost
and
people
are
learning
more
about
the
hypothetical
scare
of
a
contaminant
than
they
are
of
the
well
documented
benefits
of
coronary
disease
reduction.
The
danger
of
the
tuna
fish
is
not
well
documented
compared
to
the
potential
dangers
for
a
50­
year­
old
male
or
female
who
are
at
a
much
higher
risk
of
coronary
health."

Response:

EPA
acknowledges
that
there
are
complexities,
including
a
variety
of
potential
confounders,
that
must
be
considered
in
relation
to
potential
cardiovascular
mortality
linked
to
methylmercury
exposure.
For
additional
discussion
of
this
endpoint,
see
Appendix
D
and
Appendix
B
of
RIA
for
this
rule.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
presents
Figure
O1
to
show
the
rarely
seen
"
evidence"
that
both
EPA
and
the
"
NAS
review"
in
2000
(
see
more
criticisms
of
the
"
NAS"
[
actually
NRC
(
2000)]
review
under
comment
P
below)
had
adopted
to
support
their
claims
of
negative
neurodevelopmental
impacts
from
prenatal
exposure
to
MeHg
through
maternal
consumption.
The
result
was
drawn
from
the
Faroe
Island
children
study
originally
published
by
Grandjean
et
al.
(
1997,
Neurotoxicology
and
Teratology,
vol.
19,
417­
428)
and
the
particular
endpoint
test
(
see
additional
criticisms
by
CSPP
in
comment
Q
below)
is
the
so­
called
cued
Boston
Naming
Test
(
note
that
this
is
not
to
be
equated
to
"
IQ"
as
represented
in
the
final
section
of
EPA's
NODA).
9­
286
The
commenter
points
out
that
Figure
O1
clearly
suggests
a
significant
scatter
in
the
test
scores
as
MeHg
exposure
level
changes.
It
is
also
worth
reminding
that
this
particular
endpoint
is
indeed
the
best
evidence
allowing
the
EPA
and
"
NAS"
suggestions
of
negative
impacts
with
increasing
MeHg
exposure
 
as
guided
by
various
statistical
fitting
lines
in
Figure
O1
despite
the
large
scatter.
More
important
to
note
in
Figure
O1
is
the
relative
position
of
the
EPA
adopted
level
of
MeHg
RfD
in
the
equivalent
blood
Hg
levels
of
5.8
ppb
(
marked
as
red
dashed
vertical
line
in
Figure
01).
The
superposition
of
the
EPA's
adopted
MeHg
RfD
shows
a
clear
disconnect
to
the
underlying
data
which
forms
the
original
claim
for
negative
impacts
linked
to
MeHg
exposures.
The
commenter
believes
that
this
result
makes
clear
the
distinction
between
the
actual
levels
of
harm
or
concern
for
MeHg
and
the
hypothetical
and
ultra­
precautionary
level
of
safety
set
by
EPA's
RfD
shown
in
Figure
L1
above.

The
commenter
notes
that
there
are
even
more
serious
issues
in
the
underlying
epidemiological
data
from
the
Faroe
Island
children
study
which
exposes
its
selection
for
an
RfD
level
as
highly
inappropriate.
Not
the
least
of
which
is
the
refusal
of
the
Faroe
Islands
researchers
to
release
their
raw
data
to
allow
independent
statistical
analyses
violates
EPA's
own
data
quality
guidelines.

The
MeHg
exposure
profile
for
the
Faroe
Island
study
is
neither
compatible
nor
directly
applicable
to
U.
S.
fish
consumers.
By
admissions
of
the
original
Faroe
Island
study
researchers
(
mainly
Dr.
Philippe
Grandjean
and
Dr.
Pal
Weihe)
and
several
published
scientific
evaluations
of
the
Faroe
Island
study,
the
Faroe
Island
results
should
best
be
considered
as
a
study
assessing
exposures
to
a
mixture
of
chemicals
like
PCBs,
DDT
and
MeHg
rather
than
MeHg
alone.
It
has
long
been
noted
and
admitted
that
the
Faroe
Island
study
cohorts
were
contaminated
by
maternal
exposure
to
high
levels
of
DDT
and
PCBs
via
consumption
of
pilot
whale
meat
and
fat.
The
PCBs
levels
were
evaluated
to
be
about
600
times
the
so­
called
Aroclor
1254
RfD
level
established
by
EPA's
own
Integrated
Risk
Information
System
(
Dourson
et
al.,
2001,
Neurotoxicology,
vol.
22,
677­
689).

In
addition,
the
commenter
states
that
it
should
not
go
unnoticed
that
in
a
letter
to
the
EPA,
Drs.
Kenneth
Poirer
and
Michael
Dourson,
both
as
former
EPA's
RfD/
Reference
Concentration
Work
Group
co­
chairs,
had
previously
provided
their
scientific
findings
to
the
Technical
Information
Staff
at
EPA,
advising
that:
"
The
Faeroe
Island
studies
are
not
the
proper
choice
for
the
critical
study
for
a
methylmercury
RfD."
EPA
continues
to
ignore
this
and
more
recent
scientific
evaluations.

Finally,
in
a
February
9,
2004
open
letter
there
is
the
crucial
clarification
by
Faroe
Island
Children
Study's
Chief
Physician,
Dr.
Pal
Weihe,
that
the
Faroese
children
are
exposed
to
Hg
by
consumption
of
pilot
whale
meat
only,
not
fish.
In
contrast,
says
Dr.
Weihe,
the
fish
consumption
most
likely
is
beneficial
to
their
health.
Dr.
Weihe's
letter
follows:
9­
287
To
whom
it
may
concern:

Faroe
Islands
women
do
not
eat
Hg­
tainted
fish
and
fish
consumption
does
not
harm
Faroese
children.

In
the
Boston
Herald,
Friday,
February
6,
2004,
p.
20
the
following
was
stated
about
a
Hg
study
in
the
Faroe
Islands
conducted
in
the
cooperation
with
the
Harvard
University:
"
A
fish
industry
spokesman
said
that
the
Harvard
study
was
flawed
because
Faroe
Islands
women
typically
eat
far
more
mercury­
tainted
fish
than
do
Americans."

As
the
researcher
in
charge
of
the
Hg
studies
on
children
in
the
Faroe
Islands
since
1985
I
want
to
correct
this
statement.
The
Faroese
children
are
not
exposed
to
methylmercury
by
eating
fish.
They
are
exposed
to
Hg
by
the
traditional
consumption
of
pilot
whale
meat.
Fish
normally
consumed
in
the
Faroes,
e.
g.
Cod
and
haddock,
are
low
in
Hg
and
do
not,
to
my
opinion
constitute
any
threat
to
the
health
of
the
Faroese
children.
In
the
contrary
the
fish
consumption
most
likely
is
beneficial
to
their
health.

The
Faroese
authorities
in
1998
recommended
women
who
plan
to
become
pregnant
within
months,
pregnant
women,
and
nursing
women
to
abstain
from
eating
pilot
whale
meat.
The
Hg
concentration
in
the
blood
of
pregnant
women
has
declined
dramatically
since
and
are
now
below
the
US­
EPA
limit.

Yours
sincerely,
Pal
Weihe,
Chief
Physician
The
commenter
asks,
how
can
EPA
or
the
National
Research
Council
seriously
cling
to
the
Faroe
study
for
its
RfD
for
fish
consumption
when
the
lead
author
states
the
study
has
nothing
to
do
with
MeHg
in
fish,
but
only
in
whale
meat?
How
can
Dr.
Grandjean
claim
associations
between
IQ
levels
in
Faroese
children
and
fish
consumption
(
see
further
discussion
under
comment
Q
below)
when
Dr.
Weihe
reports
that
those
children
(
a)
are
not
exposed
to
MeHg
by
eating
fish,
(
b)
are
exposed
to
no
health
threat
from
fish,
and
(
c)
actually
benefit
from
maternal
fish
consumption?

The
commenter
urges
EPA
to
discontinue
relying
on
the
very
weak
(
and
inappropriate)
scientific
foundation
to
base
its
claim
of
negative
impacts
on
children
neurodevelopments
using
the
results
of
the
inferior
Faroe
children
study.

The
commenter
further
documents
here
additional
evidence
of
the
extremism
or
ultraprecautionary
nature
of
the
current
EPA
RfD
for
MeHg.

First,
it
is
clear
from
the
ethical
guidelines
established
by
the
Institutional
Review
Board
of
the
National
Center
for
Health
Statistics
of
the
CDC
that
approved
the
NHANES
study
that
9­
288
cautions
are
issued
to
NHANES
participants
only
if
their
total
hair
Hg
levels
are
above
15
ppm
or
total
blood
Hg
above
200
ppb
(
McDowell
et.
al.,
2004,
Environmental
Health
Perspectives,
in
press,
available
online
May
27,
2004).
The
ultra­
precaution
by
EPA
is
connected
to
its
RfD
which
considers
a
blood
Hg
level
to
be
safe
only
at
levels
below
5.8
ppb,
which
is
dramatically
lower
than
the
ethical
guideline
established
by
the
Institutional
Review
Board
of
CDC.

Second,
it
is
obvious
from
the
latest
results
of
the
Japanese
hair
Hg
measurements
for
8665
individuals
collected
in
10
different
locations
over
1999
to
2002
by
Yasutake
et
al.
(
2004,
Journal
of
Health
Science,
vol.
50
(
2),
120­
125)
that
the
overwhelming
majority
of
the
Japanese
population,
i.
e.,
87
percent,
has
hair
mercury
levels
exceeding
the
mercury"
safety"
level
set
by
EPA's
RfD.
Since
there
is
no
detectable
epidemics
of
any
defective
mental
capability
of
both
the
Japanese
adult
and
children
populations,
the
commenter
suggested
that
such
reality
confirms
the
ultra­
precautionary
nature
of
the
current
EPA
RfD
level
for
MeHg,
and
conclude
that
the
actual
levels
of
concern
from
MeHg
exposure
occurs
at
much
higher
levels
(
see
for
example,
various
values
identified
in
Figure
L1)
than
an
the
RfD
value
of
5.8
ppb
in
blood
Hg
adopted
by
EPA.

Response:

EPA
acknowledges
that
there
are
complexities,
including
a
variety
of
potential
confounders,
that
must
be
considered
in
relation
to
potential
cardiovascular
mortality
linked
to
methylmercury
exposure.
For
additional
discussion
of
this
endpoint,
see
Appendix
D.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
believes
that
this
particular
statement
by
EPA
is
both
confusing
and
misleading.
The
statement
all
by
itself
appears
contradictory
to
what
was
stated
in
comment
(
O)
that
EPA's
RfD
was
derived
from
a
single
neurodevelopmental
endpoint.

In
addition,
the
commenter
believes
that
any
reference
to
the
NRC
(
2000)
report,
Toxicological
Effects
of
Methylmercury,
about
the
review
and
assessment
of
these
three
epidemiological
studies
would
be
more
complete
in
noting
that:

"
The
committee
concludes
that
there
do
not
appear
to
be
any
serious
flaws
in
the
design
and
conduct
of
the
Seychelles,
Faroe
Islands,
and
New
Zealand
studies
that
would
preclude
their
use
in
a
risk
assessment.
However,
because
there
is
a
large
body
of
scientific
evidence
showing
adverse
neurodevelopmental
effects
[
unfortunately,
the
NRC
did
not
provide
any
precise
citation
for
such
evidence]
...
the
committee
concludes
that
an
RfD
should
not
be
derived
from
a
study,
such
as
the
Seychelles
study,
that
did
not
observe
an
association
with
MeHg."
(
p.
6)

Therefore,
the
commenter
concludes
that
the
high­
quality
results
from
the
Seychelles
study
(
with
additional
assessment
noted
below)
were
ignored
by
NRC
(
2000)
not
for
any
scientifically
defensible
reasons,
but
because
of
a
direct
bias
to
recommend
only
results
that
show
evidence
for
"
adverse
neurodevelopmental
effects."
This
situation
is
truly
unfortunate
because
it
9­
289
is
relatively
well­
known
that
the
results
of
the
Faroe
Island
study
had
been
contaminated
by
simultaneous
exposures
to
other
toxic
chemicals
like
PCBs
and
DDT.

A
post
NRC
(
2000)
analysis
by
Dourson
et
al.
(
2001,
Neurotoxicology,
vol.
22,
677­
689)
recommended
that
"
The
Faroe
Islands
data
are
from
exposures
to
a
mixture
of
chemicals.
The
Seychelles
Island
data
are
from
exposures
to
primarily
one
chemical,
MeHg....
We
would...
encourage
EPA
to
use
the
Seychelles
Island
data
as
the
basis
of
its
MeHg
RfD."

The
commenter
believes
that
this
is
why
it
is
scientifically
appropriate
to
challenge
the
biased
conclusions
of
NRC
(
2000)
and
hence
EPA's
basis
for
its
MeHg
RfD.
The
Seychelles
Island
results
are
clearly
superior
for
deriving
RfD
exposure
to
MeHg
for
the
U.
S.
population.
This
is
so
simply
because
that
study
is
without
toxic
confounders
and
the
Seychelles
Island
mothers
consumed
ocean
fish
containing
MeHg
concentrations
comparable
to
those
consumed
by
the
general
U.
S.
population.

In
contrast
to
the
Faroe
Island
study,
the
Seychelles
Child
Development
Study
(
SCDS),
"
was
specifically
designed
to
test
the
validity
of
[
the]
hypothesis
[
of
adverse
neurodevelopmental
effects]
in
a
well­
nourished
population
exposed
to
MeHg
only
from
high
consumption
of
unpolluted
ocean
fish."
The
research
authors
recently
concluded:

"[
SCDS]
longitudinal
assessment
at
9
years
of
age
indicates
no
detectable
adverse
effects
in
a
population
consuming
large
quantities
of
a
wide
variety
of
ocean
fish.
These
results
are
consistent
with
our
earlier
findings
in
the
same
children
examined
at
6,
19,
29
and
66
months
of
age.
In
Seychelles,
fetal
exposure
was
continuous
through
frequent
consumption
of
ocean
fish
containing
concentrations
of
MeHg
comparable
to
those
consumed
by
the
general
population
in
the
USA.
We
recorded
effects
from
covariates
known
to
affect
child
development,
but
did
not
find
an
association
with
prenatal
mercury"
(
p.
1692
of
Myers
et
al.,
2003,
The
Lancet,
vol.
361,
1686­
1692).

Constantine
Lyketsos
of
the
John
Hopkins
Hospital
(
2003,
Lancet,
vol.
361,
p.
1668)
in
offering
a
professional
overview
on
the
implications
of
the
Seychelles
study
concluded:

"
On
balance,
the
existing
evidence
suggests
that
methyl
mercury
exposure
from
fish
consumption
during
pregnancy,
of
the
level
seen
in
most
parts
of
the
world,
does
not
have
measurable
cognitive
or
behavioral
effects
in
later
childhood.
This
conclusion
is
especially
true
against
the
background
of
the
several
other
variables
that
affect
cognitive­
behavioral
development.
The
positive
findings
from
the
Faeroe
Islands
and
New
Zealand
studies
may
be
related
to
the
fact
that
pilot­
whale
blubber
and
shark
muscle
contain
5­
7
times
the
concentrations
of
methyl
mercury
than
the
fish
consumed
in
the
Seychelles.
While
higher
concentrations
in
seafood
do
not
necessarily
lead
to
higher
levels
in
maternal
hair,
consumption
of
much
larger
boluses
by
the
mother
could
lead
to
greater
difficulty
on
the
part
of
the
developing
fetus
to
detoxify
the
mercury
by
natural
mechanisms,
as
Meyers
and
9­
290
colleagues
propose.
Whatever
the
answer,
the
discrepant
findings
from
the
various
studies
need
explaining.
Whilst
there
is
always
an
issue
of
power
to
detect
an
effect
in
a
study
reporting
null
findings,
this
is
not
likely
to
be
the
case
in
the
Seychelles
study
with
the
sample
size
involved.
If
there
is
subtle
association
that
could
only
have
been
detected
in
a
much
larger
sample
or
through
the
use
of
more
sensitive
tests,
it
can
reasonably
be
argued
that
the
effect
would
be
small
enough
to
be
essentially
meaningless
from
the
practical
point
of
view.
For
now,
there
is
no
reason
for
pregnant
women
to
reduce
fish
consumption
below
current
levels,
which
are
probably
safe."

Response:

In
deriving
the
reference
dose
for
methylmercury,
EPA
relied
on
an
integrated
analysis
involving
three
studies.
These
longitudinal,
developmental
studies
were
conducted
in
the
Seychelles
Islands,
the
Faroe
Islands,
and
New
Zealand.
The
Seychelles
study
yielded
scant
evidence
of
impairment
related
to
in
utero
methylmercury
exposure,
whereas
the
other
two
studies
found
dose­
related
effects
on
a
number
of
neuropsychological
endpoints.
In
the
assessment
developed
for
the
RfD,
emphasis
is
placed
on
the
results
of
the
Faroe
Islands
study,
the
larger
of
the
two
studies
that
identified
methylmercury­
related
developmental
neurotoxicity.
Supporting
evidence
from
the
New
Zealand
study
provides
assurance
that
choosing
this
focus
is
the
appropriate
strategy
for
protecting
public
health.
Conclusions
from
the
National
Research
Council
review
of
methylmercury
support
this
use
of
the
Faroes
Island
study
and
disagree
with
the
suggestion
of
a
role
for
PCBs
in
the
neurological
effects
observed
(
NRC.
2000.
Toxicological
Effects
of
Methylmercury.
National
Academy
Press.),
saying
that
"
The
committee
concludes
that
there
do
not
appear
to
be
any
serious
flaws
in
the
design
and
conduct
of
the
Seychelles
Islands,
Faroe
Islands,
and
New
Zealand
studies
that
would
preclude
their
use
in
a
risk
assessment."

The
Agency's
derivation
of
the
RfD
also
followed
the
National
Research
Council
recommendation
for
an
overall
composite
uncertainty
factor
of
no
less
than
10.

In
summary,
the
Agency's
overall
confidence
in
this
RfD
assessment
is
high.
Three
high­
quality
epidemiological
studies
published
since
the
last
derivation
of
the
oral
RfD
in
1995,
have
been
included
in
the
analysis.
Two
of
the
studies
(
Faroe
Islands,
New
Zealand)
reported
effects
on
a
number
of
neuropsychological
endpoints,
whereas
the
third
(
Seychelles
Islands)
reported
no
effects
related
to
in
utero
exposure
to
methylmercury.
Benchmark
dose
analysis
of
a
number
of
endpoints
from
both
the
New
Zealand
and
Faroe
Islands
study
converged
on
an
RfD
of
0.1
µ
g/
kg­
day,
as
did
the
integrative
analysis
combining
all
three
studies.
Although
there
was
coexposure
to
PCBs
in
the
Faroe
Islands
study,
statistical
analysis
indicated
that
the
effects
of
PCBs
and
methylmercury
were
independent.
Moreover,
benchmark
dose
analysis
of
the
endpoints
that
were
significantly
associated
with
methylmercury
yielded
RfDs
that
were
approximately
the
same
when
corrected
for
PCBs.
The
same
was
true
when
the
analysis
was
or
based
on
the
subset
of
the
cohort
in
the
lowest
tertile
with
respect
to
PCB
levels,
as
compared
9­
291
with
the
full
cohort.
These
findings
provide
further
evidence
that
the
identified
effects
are
in
fact
the
result
of
methylmercury
exposure.

Comment:

One
commenter
(
OAR­
2002­
0056­
5423)
notes
that
the
primary
author
the
Faroe
Island
study,
Dr.
Philippe
Grandjean,
was
found
to
have
admitted
in
the
May
20,
2002
Mercury
Forum
held
at
Mobile,
Alabama
(
http://
www.
masgc.
org/
mercury/)
that
"
In
conclusion,
the
commenter
had
obtained
evidence
of
subtle
adverse
effects
on
neurobehavioral
functions,
blood
pressure,
and
growth.
At
age
7
years,
a
doubling
of
the
Hg
exposure
corresponds
to
a
developmental
delay
of
up
to
2
months.
Although
IQ
tests
were
not
done,
such
delays
would
be
comparable
to
a
loss
of
about
1.5
IQ
points."

Another
relevant
notice
is
the
statement
in
Dr.
Grandjean's
written
testimony
at
the
Mercury
MACT
Rule
Hearing
at
Maine
State
House
on
March
1,
2004,
that
"
Even
though
the
children
that
the
commenter
examined
were
all
basically
normal,
we
have
documented
detectable
deficits
that
appear
to
be
permanent."
CSPP
takes
the
statement
to
suggest
that
Faroese
children
are
essentially
all
normal
with
normal
functioning
capability
despite
the
permanent
"
detectable
deficits"
of
the
sort
described
by
Grandjean.

Finally,
it
was
also
clear
that
the
cued
Boston
Naming
Test
conducted
by
the
Faroe
study
does
not
constitute
a
proper
IQ
test.

The
commenter
believes
that,
in
short,
Dr.
Grandjean's
statements
are
contradictory
at
best.
They
would
not
hold
up
in
a
rigorous
scientific
evaluation
by
other
experts
or
his
peers.
They
should
not
go
unchallenged
by
EPA
either,
especially
as
his
raw
data
are
not
transparent.

But
the
commenter
notes
that
the
really
relevant
question
to
assessing
the
statement
in
(
Q)
is
whether
if
any
or
all
of
these
reputed
neurodevelopmental
outcomes
and
tests
can
be
shown
to
be
related
to
MeHg
exposure.
In
that
regard,
it
is
important
to
consider
that
for
a
total
17
neuropsychological
tests
conducted
by
the
Faroe
study
to
search
for
associations
with
prenatal
exposure
to
MeHg,
only
3
tests
(
both
the
cured
and
uncured
Boston
Naming
Tests
and
the
socalled
Neurobehavioral
Evaluation
System
Continuous
Performance
Test)
yielded
statistically
significant
correlations
only
if
the
Faroe
researcher
considers
maternal
cord
blood
as
an
independent
predictor
(
Budd­
Jorgensen
et.
al.,
2003,
Environmetrics,
vol.
14,
105­
120).
The
statistical
correlation
for
the
same
3
test
scores
dramatically
turned
insignificant
or
only
marginally
significant
when
the
measured
maternal
hair
Hg
is
adopted
as
the
independent
variable
instead.

Dr.
Gary
Myers,
one
of
the
main
authors
of
the
Seychelles
Island
Child
Development
Study,
makes
the
point
that
even
the
3
statistical
associations
found
by
the
Faroe
Island
study
are
a
lot
less
impressive
than
one
is
lead
to
think
if
one
properly
weighs
in
the
statistical
odds.
In
a
July
29,
2003'
s
testimony
to
the
Senate
Environment
and
Public
Work
Committee,
Myers
noted:

"
Through
107
months
(
9
years)
and
over
57
primary
endpoints,
the
[
Seychelles
9­
292
Island]
study
has
found
only
three
statistical
associations
with
prenatal
MeHg
exposure.
One
of
these
associations
was
adverse,
one
was
beneficial
and
one
was
indeterminate.
These
results
might
be
expected
to
occur
by
chance
and
do
not
support
the
hypothesis
that
adverse
developmental
effects
result
from
prenatal
MeHg
exposure
in
the
range
commonly
achieved
by
consuming
large
amounts
of
fish.
The
test
results
do
show
associations
with
factors
known
to
affect
child
development
such
as
maternal
IQ
and
home
environment
so
there
is
evidence
that
the
tests
are
functioning
well
[
i.
e.,
the
Seychelles
Island
Child
Development
Study
shows
evidence
for
a
high
degree
of
internal
consistency]."

Myer
concluded
in
his
senate
testimony:

"
We
do
not
believe
that
there
is
presently
good
scientific
evidence
that
moderate
fish
consumption
is
harmful
to
the
fetus.
However,
fish
is
an
important
source
of
protein
in
many
countries
and
large
numbers
of
mothers
around
the
world
rely
on
fish
for
proper
nutrition.
Good
maternal
nutrition
is
essential
to
the
baby's
health.
Additionally,
there
is
increasing
evidence
that
the
nutrients
in
fish
are
important
for
brain
development
and
perhaps
for
cardiac
and
brain
function
in
older
individuals."

The
commenter
believes
that
in
the
context
of
positive
or
negative
brain
development
from
trace­
Hg
fish
consumption,
real
world
data
trumps
modeling
or
alarmist
assertions.
For
example,
in
the
latest
data
from
the
Trends
in
International
Mathematics
and
Science
Study,
students
(
grade
4
and
8)
in
Asia
continued
to
excel.
Singapore,
Hong
Kong,
Japan
and
Korea
were
among
the
top
performers
in
over
50
countries
participating.
The
U.
S.
placed
well
below
these
countries.
As
EPA
noted,
Asians
are
among
the
largest
fish
consuming
peoples
in
the
world.
If
alarming
neuropsychological
and
neurodevelopmental
deficits
from
prenatal
MeHg
exposure
through
fish
consumption
(
as
interpreted
by
Dr.
Grandjean
in
the
Faroe
children
study)
are
correct,
then
these
Asian
students
are
the
very
populations
that
should
be
evidencing
an
epidemic
in
low
IQ,
instead
of
topping
the
curve
on
international
standardized
math
and
science
tests.

Response:

As
many
factors
influence
performance,
relative
rankings
on
the
International
Mathematics
and
Science
Study
are
not
indicative
of
the
impact
of
MeHG.
As
stated
above,
in
deriving
the
reference
dose
for
methylmercury,
EPA
relied
on
an
integrated
analysis
involving
three
studies.
These
longitudinal,
developmental
studies
were
conducted
in
the
Seychelles
Islands,
the
Faroe
Islands,
and
New
Zealand.
The
Agency's
overall
confidence
in
this
RfD
assessment
is
high.
The
US
Government
also
emphasizes
that
fish
and
shellfish
are
an
important
part
of
a
healthy
diet
for
women
and
young
children;
and
that
women
and
young
children
should
include
fish
or
shellfish
in
their
diets
due
to
the
many
nutritional
benefits.
Recommendations
for
selecting
and
eating
fish
or
shellfish
are
made
by
EPA
and
FDA.
These
recommendations,
if
followed,
should
enable
women
and
young
children
to
receive
the
benefits
of
eating
fish
and
shellfish
and,
at
the
same
time,
they
can
be
confident
that
they
have
minimized
their
exposure
to
the
harmful
effects
of
mercury.
9­
293
Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
stated
that
in
response
to
EPA's
request
for
feedback
on
the
comments
submitted
by
the
Electric
Power
Research
Institute
("
PERI")
and
the
UARG
(
see
69
Fed.
Reg.
at
69,873
[
2nd
Column]),
the
commenter
noted
that
those
comments
suffer
from
profound
factual,
logical
and
legal
flaws.
The
commenter
further
stated
that,
accordingly,
EPA
need
not
attempt
to
respond
to
every
last
technical
assertion
advanced
by
those
commenters.
The
commenter
added
that
listed
below
are
two
illustrative
examples
of
threshold,
overarching
problems
in
the
PERI
and
UARG
comments.

The
commenter
stated
that,
first,
in
a
strained
attempt
to
argue
that
domestic
power
plants
do
not
contribute
to
Hg
hot
spots,
PERI
writes
that
a
particular
"
geographic
location"
is
"
utility­
influenced"
only
if
50
percent
or
more
of
the
Hg
depositing
there
stems
from
utilities
(
See
OAR­
2002­
0056­
2578
["
PERI
Comments"]).
But,
the
commenter
stated,
PERI
provides
no
reason
to
adopt
its
definition
of
"
utility­
influenced"
and
no
such
reason
exists.
The
commenter
added
that,
plainly,
utilities
can
contribute
less
than
50
percent
of
the
Hg
in
a
given
location
and
still
influence
that
location.
See,
e.
g.,
William
L.
Prosser,
W.
Page
Keeton,
et
al.,
The
Law
of
Torts
§
52
(
5th
ed.
1984)
("
Pollution
of
a
stream
to
even
a
slight
extent
becomes
unreasonable
when
similar
pollution
by
others
makes
the
condition
of
the
stream
approach
the
danger
point.");
U.
S.
v.
Alcan
Aluminum
Corp.,
315
F.
3d
179,
187
(
2d
Cir.
2003)
(
explaining
that
harm
that
is
minimal
on
its
own
may
be
significant
when
combined
with
other
harms).
The
commenter
stated
that,
in
addition,
EPRI's
argument
that
domestic
power
plants
do
not
cause
hot
spots
cannot
be
reconciled
with
its
simultaneous
assertion
that
the
"
state­
of­
the­
science
is
too
imprecise"
to
measure
the
significance
of
reduced
Hg
emissions
(
see
also
OAR­
2002­
0056­
2922
(
UARG
Comments)).
The
commenter
further
stated
that
PERI
is
simultaneously
claiming
that
EPA
cannot
measure
the
consequences
of
reducing
Hg
emissions
and
that
power
plants
are
only
a
small
part
of
the
Hg
problem.
The
commenter
stated
that
PERI
cannot
have
it
both
ways:
Either
the
significance
of
power
plant
emissions
can
be
measured
with
precision,
or
it
cannot
be.
The
commenter
stated
that
,
in
all
events,
however,
EPA
has
already
determined
that
Hg
power
plant
emissions
require
regulation
pursuant
to
Section
112,
and
no
factual
or
legal
basis
exists
to
undo
that
decision
now.

Response:

EPA
has
examined
the
commenter's
concerns
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
EPA
has
addressed
the
hot
spots
issue
in
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112
Notice
and
in
the
Technical
Support
Document:
Methodology
Used
to
Generate
Deposition,
Fish
Tissue
Methylmercury
Concentrations,
and
Exposure
for
Determining
Effectiveness
of
Utility
Emission
Controls
in
the
docket.
9­
294
Comment:

The
commenter
(
OAR­
2002­
0056­
5460)
states
that
with
regard
to
step
five
of
EPA's
proposed
revised
benefits
assessment
methodology,
EPA
has
not
adequately
explained
several
aspects
of
its
focus
on
IQ
as
the
neurodevelopmental
endpoint.
See
69
Fed.
Reg.
at
69,878.
The
commenter
further
stated
that,
for
example,
EPA
has
not
adequately
explained
why
it
is
not
also
evaluating
other
neurodevelopmental
endpoints.
The
commenter
added
that
it
has
likewise
failed
to
explain
how
it
will
use
the
Faroe
Islands
and
Seychelles
Islands
studies
to
measure
IQ
decrements,
especially
given
its
admission
that
those
studies
did
not
conduct
sufficient
tests
to
estimate
IQ.

Response:

As
part
of
its
analysis
of
the
final
rule,
EPA
has
estimated
some
of
the
health
benefits
of
reducing
Hg
from
utilities.
At
this
time
EPA
is
only
able
to
provide
quantative
estimates
of
the
benefits
of
reducing
neurological
impacts
of
exposure
to
MeHg
for
a
portion
of
the
U.
S.
population.
Please
refer
to
Chapter
2
of
the
RIA
for
a
description
of
approach
and
rationale.

Comment:

One
commenter
(
OAR­
2002­
0056­
5497)
stated
that
the
NODA
indicated
that
an
analysis
currently
being
performed
by
EPA
and
Harvard
researchers
will
be
peer­
reviewed
and
placed
in
the
docket
"
as
soon
as
it
is
available."
The
commenter
questions
whether
EPA
can
even
complete
the
detailed
analysis
described
in
Step
5
by
March
15,
2005
 
the
date
on
which
EPA
says
it
will
issue
a
final
CAMR
 
much
less
having
it
peer
reviewed.
The
commenter
further
doubts
whether
interested
parties
will
have
a
meaningful
opportunity
to
review
and
comment
on
this
analysis
before
a
final
rule
is
issued.
This
lack
of
a
meaningful
comment
opportunity
is
of
particular
concern
because
this
last­
minute
analysis
appears
to
be
designed
to
overstate
whatever
health
effects
may
result
from
Hg
emissions
from
coal­
fired
power
plants.

The
commenter
asked
why
was
this
detailed
health
effects
assessment
not
included
as
part
of
the
Hg
or
utility
studies?
Why
was
it
not
presented
as
part
of
the
proposed
rulemaking
package?
A
number
of
questions
in
this
part
of
the
NODA
involve
human
health
assumptions
and
approaches
that
are
significantly
different
than
those
recommended
by
the
National
Academy
of
Science
(
NAS)
and
those
used
by
EPA
in
establishing
a
Reference
Dose
(
RID)
for
MeHg.
Why
were
those
new
approaches
not
vetted
as
part
of
the
Integrated
Risk
Information
System
(
IRIS)
database
process
or
in
some
broader
forum?

The
commenter's
earlier
comments
contained
a
series
of
criticisms
about
EPA's
RID
process.
Those
comments
expressed
concerns
about
how
EPA
had
manipulated
assumptions
to
produce
a
reference
dose
that
was
lower
than
ones
produced
by
other
federal
or
international
organizations.
Many
of
the
questions
posed
by
EPA
in
the
NODA
seem
aimed
at
further
manipulating
available
information
to
find
even
lower
levels
of
cause
and
effect
relationships.
9­
295
Question
a:
The
focus
of
neurodevelopmental
health
of
children
The
neurodevelopmental
health
of
children
should
remain
the
focus
of
MeHg
health
effects.
Other
health
endpoints
such
as
cardiovascular
effects
should
not
be
used
in
place
of
neurodevelopmental
effects
on
children.
The
cardiovascular
studies
cited
by
EPA
and
other
commenters
raise
many
scientific
questions.
The
cardiovascular
studies
have
yielded,
contradictory
results.
The
Finnish
study
by
Salonen
that
first
raised
concerns
about
the
linkage
between
MeHg
exposure
and
cardiovascular
disease
has
many
problems.
These
problems
are
discussed
in
detail
in
EPRI's
NODA
comments
and
comments
submitted
by
the
Center
for
Science
and
Public
Policy.
Briefly,
Salonen's
conclusions
rest
on
relative
risk
relationships
that
are
so
low
as
to
be
questionable
whether
they
really
exist.
In
addition,
coronary
heart
disease
has
multiple
risk
factors
that
cannot
be
completely
controlled
in
a
study
design
 
the
eastern
Finland
study
group
had
high
intake
of
meat,
fish
and
saturated
animal
fat
and
a
low
intake
of
vitamins
and
other
vegetable­
derived
antioxidants.
Finally,
follow­
up
studies
of
this
Finnish
population
were
greatly
separated
in
time,
casting
further
doubts
on
Salonen's
findings.

The
ongoing
National
Health
and
Nutrition
Examination
Study
("
NHANES")
study
has
failed
to
find
a
relationship
between
blood
Hg
concentrations
and
blood
pressure,
raising
further
questions
about
the
relationship
between
MeHg
exposures
and
cardiovascular
disease.
Therefore,
the
focus
of
any
benefits
analysis
should
remain
on
the
neurodevelopmental
health
of
children,
until
other
health
endpoints
have
been
studied
to
the
extent
of
the
neurodevelopmental
ones
and
those
other
endpoints
are
shown
to
be
more
sensitive
than
the
neurodevelopmental
ones.

Question
b:
The
selection
of
IQ
as
an
endpoint
for
quantification
of
neurodevelopmental
effects
and
whether
it
is
an
appropriate
endpoint
for
benefits
analysis
for
reduced
exposure
to
MeHg
There
is
no
indication
that
IQ
is
a
good
measure
of
potential
impacts
of
prenatal
MeHg
exposure.
The
Seychelles
and
New
Zealand
studies
did
not
find
statistically
significant
associations
between
MeHg
exposures
and
IQ
reductions.
Testing
in
the
Faroes
did
not
include
measures
of
I
Q.
Indeed,
there
was
no
consensus
among
the
three
tests
in
the
design
phase
that
IQ
was
an
important
domain
that
was
likely
to
be
affected
by
MeHg
exposure.

As
EPRI's
NODA
comments
explain
in
greater
detail,
IQ
tests
are
not
a
validated
measure
of
brain
function.
Furthermore,
the
lack
of
a
global
IQ
measure
can
mask
subtle
changes
in
a
specific
domain.

Quite
simply,
the
fact
that
IQ
differences
can
be
monetized
in
a
benefits
analysis
does
not
make
IQ
a
good
measure
of
MeHg
exposure.

Question
c:
Whether
other
neurodevelopmental
effects
can
be
quantified
and
are
amenable
to
economic
valuation
At
this
time,
The
commenter
does
not
offer
a
response
to
this
question.
9­
296
Question
d:
Whether,
and
if
so
how,
data
from
the
Faroes
Islands,
New
Zealand,
and
Seychelles
Islands
studies
can
be
integrated
for
purposes
of
a
benefits
assessment
EPRI's
NODA
comments
explain
in
great
detail
why
integrating
the
Faroes,
Seychelles
and
New
Zealand
results
into
a
meta
analysis
is
not
scientifically
sound.
The
commenter
agreed
with
those
comments.
Factors
that
hinder
integration
include:
different
study
populations
that
have
cultural
differences
and
different
possible
confounders,
different
testing
ages
among
the
study
subjects,
different
diets
(
the
diets
in
the
Seychelles
and
New
Zealand
were
based
largely
fish
consumption
while
the
diet
in
the
Faroes
relied
heavily
on
consumption
of
pilot
whale),
differences
in
exposure
measurements
(
the
Faroes
researchers
used
cord
blood
while
the
Seychelles
and
New
Zealand
researchers
used
hair
samples),
different
outcome
tests
were
used
in
each
study,
and
differences
in
the
covariates
measured
and
included
in
multivariate
analyses.
Furthermore,
there
is
no
consistent
pattern
of
significant
results
across
studies.
If
IQ
is
used
as
the
endpoint
in
the
meta
analysis,
then
a
surrogate
needs
to
be
found
for
the
Faroes
results.
The
choice
of
any
surrogate
is
problematic.
For
all
these
reasons,
the
lack
of
comparability
among
the
three
studies
precludes
combining
their
results
in
a
meta
analysis
that
could
be
used
in
a
benefits
analysis.

Question
e:
The
choice
of
the
K=
1
model
for
estimating
the
relationship
between
exposure
and
IQ
and
practical
alternatives
to
that
approach
Assuming
a
K=
1
model
is
inconsistent
with
the
recommendation
of
the
NAS
panel
which
favored
a
K
1
model.
87
A
K=
1
assumption
is
also
contrary
to
the
results
of
two
statistical
analyses
of
the
Seychelles
results
that
are
discussed
in
EPRI's
NODA
comments.
These
analyses
indicate
non­
linear
associations
between
MeHg
exposures
and
test
performance.
Thus,
the
choice
of
K=
1
model
is
not
yet
warranted.

Question
f:
The
appropriateness
and
consistency
of
using
a
linear
dose­
response
model
given
the
RfD
established
by
EPA
in
2001
(
reflecting
NAS
review
in
2000),
which
assumes
a
threshold
dose
below
which
there
is
not
likely
to
be
an
appreciable
risk
of
deleterious
effects
during
a
lifetime
In
many
ways,
this
question
answers
itself.
A
linear
dose
response
model,
that
presumably
passes
through
the
zero
point,
is
inconsistent
with
the
RID
that
EPA
has
established
for
MeHg
that
assumes
a
threshold
effect
level.
A
linear
model
is
also
inconsistent
with
similar
values
that
have
been
used
by
the
Agency
for
Toxic
Substances
and
Disease
Registry
(
ATSDR)
and
the
WHO
in
their
development
of
RID
analogues.
As
the
question
notes,
the
NAS
panel,
whose
report
EPA
relies
on
to
support
its
RID,
also
viewed
a
threshold
model
as
most
appropriate
for
MeHg.

Unfortunately,
the
NODA
offers
scant
explanation
of
why
EPA
now
believes
that
switching
to
a
linear
model
is
appropriate.
EPA
offers
no
explanation
as
to
why
it
may
now,
interpret
the
Faroes,
Seychelles
and
New
Zealand
results
as
supporting
a
linear
model.
The
NODA
simply
recites,
without
explanation,
that
a
group
of
Harvard
researchers
will
likely
assume
9­
297
a
linear
dose­
response
relationship."
The
only
other
hint
in
the
NODA
as
to
why
EPA
may
be
considering
using
a
linear
model
is
the
"
practicality"
of
using
a
linear
model
because
it
"
would
allow
[
EPA]
to
estimate
benefits
of
reductions
in
exposure
due
to
power
plants
without
a
complete
assessment
of
the
other
sources
of
exposure."
While
a
linear
model
may
ease
the
Agency's
burden,
it
is
nonsensical
to
use
such
a
model
if
it
does
not
comport
with
actual
scientific
observation.
Indeed,
a
linear
model
will
vastly
overstate
the
benefits
attributed
to
limiting
Hg
emissions
from
coal­
fired
power
plants.
EPA
should
not
change
from
its
RID
threshold
model
without
a
public
review
and
comment
process
that
at
least
rivals
the
one
it
provided
when
it
last
revised
its
MeHg
RID.
Merely
mentioning
that
the
Agency
is
considering
using
a
model
without
a
detailed
explanation
why
hardly
suffices
as
adequate
notice.

Response:

EPA
does
not
have
access
to
the
study
data
for
the
three
key
studies.
The
only
data
available
to
EPA
are
regression
coefficients
and
other
statistics
that
have
been
published
by
the
study
investigators.
Therefore,
EPA
is
not
able
to
conduct
any
modeling
that
would
examine
alternative
shapes
to
the
dose­
response
relationship,
including
non­
linear
models.
EPA's
analysis
involves
a
statistical
integration
of
linear
dose­
response
functions
that
have
been
reported
by
the
study
investigators.
We
believe
that
use
of
a
linear
function,
in
conjunction
with
using
a
nonthreshold
model,
in
our
analysis
is
well­
justified
by
the
following
considerations:
1)
The
National
Research
Council's
2000
report
on
methylmercury
used
linear
model
results
for
deriving
benchmark
doses,
and
cautioned
against
use
of
supralinear
models;
2)
the
Faroe
Islands
research
team
reported
that
K­
power
models
(
with
the
NRC­
recommended
constraint
of
K
>
1,
i.
e.,
with
supralinearity
excluded)
fit
best
with
the
linear
specification,
i.
e.,
K
=
1;
3)
linear
model
results
are
available
for
IQ
for
all
three
studies,
and
no
non­
linear
model
results
are
available
from
the
three
studies
(
except
for
Faroes
log
model),
and
raw
data
are
not
available
to
us
for
conducting
analysis
of
dose­
response
shape
or
other
issues;
and
4)
the
lowest
exposures
in
the
Faroe
Islands
study
overlap
with
U.
S.
exposure
range,
although
there
is
less
overlap
with
the
other
two
studies.
Nonetheless,
EPA's
Reference
Dose
and
the
analysis
supporting
its
derivation
was
reviewed
positively
by
the
National
Academcy
of
Sciences
and
the
Agency
continues
to
support
its
level
and
the
implications.
We
conclude
that
any
analysis
of
the
IQ
benefits
needs
to
deploy
several
models
­­
with
a
threshold
and
without
to
capture
the
full
range
of
uncertainty.
EPA
acknowledges
that
there
are
complexities,
including
a
variety
of
potential
confounders,
that
must
be
considered
in
relation
to
potential
cardiovascular
mortality
linked
to
methylmercury
exposure.
For
additional
discussion
of
this
endpoint,
see
Appendix
D.

D.
Other
Comments
Comment:

One
commenter
(
OAR­
2002­
0056­
5476)
reports
that
to
date,
it
has
yet
to
receive
any
responses
to
its
request
to
EPA
Region
5
to
fulfill
their
Trust
responsibilities
and
intervene
on
the
commenter's
behalf
in
the
rule­
making
process.
Therefore,
this
commenter
is
calling
on
EPA
Headquarters
to
act
on
its
behalf
and
set
MACT
standards
that
will
reduce
Hg
emissions
from
9­
298
utilities
by
90
percent
in
the
next
10
years.
This
will
also
fulfill
EPA's
obligations
under
the
Environmental
Justice
Doctrine.
As
outlined
in
the
Forest
County
Potawatomi's
comment
letter
to
EPA
(
see
e­
docket
OAR­
2002­
0056­
2173:
April
27,
2004),
EPA
has
recognized
its
special
obligation
to
protect
the
environmental
interests
of
the
commenter
when
carrying
out
its
duties.
The
Indian
Policy,
first
adopted
in
1984,
also
calls
for
EPA
to
work
directly
with
tribes
on
a
government­
to­
government
basis
and
to
encourage
tribes
to
participate
in
policy­
making.
It
has
not
been
made
known
to
the
commenter
of
any
efforts
that
EPA
has
made
to
fulfill
any
of
these
obligations.
No
consultation
has
taken
place
with
the
commenter,
and
the
commenter's
requests
for
Trust
responsibility
to
be
carried
out
have
remained
unaddressed.

Response:

EPA
recognizes
that
the
Federal
government
stands
in
a
government­
to­
government
relationship
with
Federally
recognized
Tribes
and
has
certain
trust
responsibilities
to
these
Tribes.
This
relationship
and
responsibility
should
guide
EPA
in
the
implementation
of
policies
and
actions
that
affect
Tribes.
Pursuant
to
the
government­
to­
government
relationship,
EPA
consults
with
Tribes
regarding
actions
that
affect
Tribes.
In
addition,
treaties,
statutes,
and
executive
orders
create
Federal
obligations
regarding
Tribal
resources.
EPA
believes
that
its
actions
in
developing
the
final
rule
have
been
consistent
with
the
government­
to­
government
relationship
and
that
the
final
rule
itself
is
consistent
with
the
trust
responsibility.

EPA
does
not
agree
with
the
commenters
who
claim
that
it
did
not
consult
with
tribes
in
developing
the
rule.
As
explained
in
the
discussion
of
EPA
compliance
with
EO
in
the
preamble
for
the
final
rule,
EPA
took
the
following
steps
to
consult
with
Tribes.
EPA
gave
a
presentation
to
a
national
meeting
of
the
National
Tribal
Environmental
Council
(
NTEC)
in
April
2001,
and
encouraged
Tribal
input
at
an
early
stage.
EPA
then
worked
with
NTEC
to
find
a
Tribal
representative
to
participate
in
the
workgroup
developing
the
rule,
and
included
a
representative
from
the
Navajo
Nation
as
a
member
the
official
workgroup,
with
a
representative
from
the
Campo
Band
later
added
as
an
alternate.
In
March
2004,
EPA
provided
a
briefing
for
Tribal
representatives,
the
newly
formed
National
Tribal
Air
Association
(
NTAA),
and
NTEC.
EPA
received
comments
on
this
rule
from
a
number
of
Tribes,
and
has
taken
those
comments
and
other
input
from
Tribal
representatives
into
consideration
in
development
of
this
rule.

EPA
disagrees
that
the
rule
will
not
adequately
protect
Tribal
fishing
rights.
EPA
agrees
that
some
Tribes
have
unique
legal
rights
to
fish
arising
from
treaties,
statutes,
executive
orders,
and
agreements.
EPA
also
recognizes
that
Tribal
members
may
catch
and
consume
more
fish
than
the
general
public
as
a
result
of
Tribal
fishing
rights
as
well
as
Tribal
culture,
traditions,
and
subsistence
lifestyles.

EPA
believes
that
this
regulation
adequately
protects
Tribal
health
and
is
consistent
with
the
trust
responsibility
for
several
reasons.
First,
the
commenters
understate
the
significance
of
the
fact
that
Hg
emissions
from
Utility
Units
currently
are
not
subject
to
performance
standards.
This
regulation
will
for
the
first
time
establish
performance
standards
applicable
to
Hg
emissions,
and
those
standards
will
require
significant
reductions
in
the
levels
of
Hg
emissions.
9­
299
Such
reductions
will
provide
greater
protection
to
Tribal
fish
resources
than
would
otherwise
be
available.
Acting
to
provide
such
heightened
protection
is
consistent
with
both
the
statute
and
the
Federal
trust
responsibility.

Moreover,
the
commenters
offer
no
specific
evidence
that
the
Hg
emissions
reductions
from
this
regulation
will
not
adequately
protect
Tribal
health.
Their
main
contention
is
that
the
regulatory
approach
set
forth
in
an
earlier
EPA
proposal
would
have
produced
a
90
percent
reduction
in
Hg
emissions
and
that
any
smaller
reduction
is,
therefore,
inadequate.
That
contention
rests
on
a
misconception
of
an
earlier
Federal
Register
Notice,
which
proposed
a
finding,
but
did
not
contain
any
specific
proposal
for
Hg
emissions
regulations,
and,
therefore,
did
not
provide
for
any
percentage
of
reduction.
EPA
has
never
proposed
any
such
rule.
EPA
believes
that
this
regulation
will
adequately
protect
Tribal
health.

The
commenters
also
argue
that
EPA
has
not
adequately
considered
the
significance
of
Tribal
fish
consumption
patterns,
specifically
the
fact
that
Tribal
fishers
consume
more
fish
than
the
general
population.
That
comment
is
misplaced.
As
described
in
more
detail
elsewhere
in
this
document,
EPA
carefully
analyzed
available
information
on
fish
consumption
by
Tribal
members
and
other
sub­
populations,
and
determined
how
to
use
the
available
data
most
appropriately.
One
basis
for
EPA's
analysis
was
a
study
of
tribal
fish
consumption
in
one
region
to
model
consumption
by
other
Tribes
as
well
as
other
subpopulations.
EPA's
approach
was
to
identify
areas
where
the
effects
of
Hg
deposition
from
utility
emissions
had
the
greatest
effects.
EPA
then
compared
those
high­
deposition
areas
with
locations
with
high
Tribal
populations
to
assess
the
areas
of
greatest
potential
risk
to
Tribes.
That
analysis
found
that
very
few
areas
where
Native
Americans
live
corresponds
with
high
residual
Hg
deposition
caused
by
utilities.
It
found
further,
that
the
standards
established
in
the
regulation
will
significantly
reduce
risks
to
tribal
members.

Finally,
as
discussed
in
the
preamble
to
the
regulation,
this
regulation
establishes
a
capand
trade
program
for
Indian
country.

As
part
of
its
analysis
of
the
this
final
rule,
EPA
has
estimated
the
some
of
the
health
benefits
of
reducing
Hg
from
utilities.
At
this
time
EPA
is
only
able
to
provide
quantative
estimates
of
the
benefits
of
reducing
neurological
impacts
of
exposure
to
MeHg
for
a
portion
of
the
U.
S.
population.
This
population
covers
people
who
recreationally
catch
and
consume
freshwater
fish.
The
RIA
for
this
rule
contains
this
analysis
in
Chapter
11.
As
part
of
its
assessment,
EPA
provides
estimates
for
the
benefits
of
this
rulemaking
to
subsistence
fishers,
including
case
study
examples
of
the
benefits
to
the
some
members
of
the
Chippewa
Tribe,
the
Hmong,
and
low
income
fishers.

Comment:

One
commenter
(
OAR­
2002­
0056­
5476)
notes
that
EPA
has
a
specific
obligation
to
protect
tribal
way
of
life
and
cultural
resources,
not
only
rights
and
resources.
Court
decisions
have
held
that
trust
responsibility
is
not
limited
to
the
protection
of
treaty
rights,
reservation
9­
300
lands,
and
other
property
held
in
trust
for
the
tribes
and
that
federal
agencies
may
not
permit
actions
which
would
interfere
with
treaty
rights.
Instead,
trust
responsibility
extends
to
all
actions
of
the
federal
governments
that
may
affect
Indian
tribes,
including
those
rights,
resources,
and
interests
recognized
under
treaty,
statue,
executive
order,
and
common
law.

The
commenter's
rights
include
rights
to
the
lands,
waters,
and
natural
environment
of
the
Reservation.
Arizona
v.
California,
373
U.
S.
546
(
1963)
holds
that
tribes
are
entitled
to
sufficient
water
and
other
resources
to
make
the
Reservation
livable
and
to
maintain
their
way
of
life.
Tribes
also
hold
rights
to
hunt,
fish
and
gather
on
reservation
lands
and
waters.

In
addition,
Congress
has
specifically
recognized
the
applicability
of
the
trust
responsibility
in
tribal
cultural
resources
by
instating
a
number
of
federal
laws
in
this
area.
Further,
the
Tribes'
right
to
practice
traditional
religions
under
the
First
Amendment
is
recognized
in
the
American
Indian
Religious
Freedom
Act,
42
U.
S.
C.
Section
1996,
1996a.
The
EPA
has
fallen
far
short
of
its
obligations
in
this
rulemaking.

Though
the
Environmental
Justice
guidelines
dictate
that
EPA
must
identify
and
address
disproportionately
high
and
adverse
human
health
or
environmental
effects
of
its
programs,
policies,
and
activities
on
minority
populations
and
low­
income
populations,
unfortunately,
it
appears
as
though
these
guidelines
are
being
largely
ignored
for
the
purposes
of
providing
special
treatment
to
utilities.
The
commenter
encourages
EPA
to
assure
the
Tribes
that
EPA
is
actively
addressing
these
Environmental
Justice
issues
per
the
guidelines
EPA
has
set
out
for
itself.

Response:

EPA
recognizes
that
the
Federal
government
stands
in
a
government­
to­
government
relationship
with
Federally
recognized
Tribes
and
has
certain
trust
responsibilities
to
these
Tribes.
This
relationship
and
responsibility
should
guide
EPA
in
the
implementation
of
policies
and
actions
that
affect
Tribes.
Pursuant
to
the
government­
to­
government
relationship,
EPA
consults
with
Tribes
regarding
actions
that
affect
Tribes.
In
addition,
treaties,
statutes,
and
executive
orders
create
Federal
obligations
regarding
Tribal
resources.
EPA
believes
that
its
actions
in
developing
the
final
rule
have
been
consistent
with
the
government­
to­
government
relationship
and
that
the
final
rule
itself
is
consistent
with
the
trust
responsibility.

EPA
does
not
agree
with
the
commenters
who
claim
that
it
did
not
consult
with
tribes
in
developing
the
rule.
As
explained
in
the
discussion
of
EPA
compliance
with
EO
in
the
preamble
for
the
final
rule,
EPA
took
the
following
steps
to
consult
with
Tribes.
EPA
gave
a
presentation
to
a
national
meeting
of
the
National
Tribal
Environmental
Council
(
NTEC)
in
April
2001,
and
encouraged
Tribal
input
at
an
early
stage.
EPA
then
worked
with
NTEC
to
find
a
Tribal
representative
to
participate
in
the
workgroup
developing
the
rule,
and
included
a
representative
from
the
Navajo
Nation
as
a
member
the
official
workgroup,
with
a
representative
from
the
Campo
Band
later
added
as
an
alternate.
In
March
2004,
EPA
provided
a
briefing
for
Tribal
representatives,
the
newly
formed
National
Tribal
Air
Association
(
NTAA),
and
NTEC.
EPA
received
comments
on
this
rule
from
a
number
of
Tribes,
and
has
taken
those
comments
and
9­
301
other
input
from
Tribal
representatives
into
consideration
in
development
of
this
rule.

EPA
disagrees
that
the
rule
will
not
adequately
protect
Tribal
fishing
rights.
EPA
agrees
that
some
Tribes
have
unique
legal
rights
to
fish
arising
from
treaties,
statutes,
executive
orders,
and
agreements.
EPA
also
recognizes
that
Tribal
members
may
catch
and
consume
more
fish
than
the
general
public
as
a
result
of
Tribal
fishing
rights
as
well
as
Tribal
culture,
traditions,
and
subsistence
lifestyles.

EPA
believes
that
this
regulation
adequately
protects
Tribal
health
and
is
consistent
with
the
trust
responsibility
for
several
reasons.
First,
the
commenters
understate
the
significance
of
the
fact
that
Hg
emissions
from
Utility
Units
currently
are
not
subject
to
performance
standards.
This
regulation
will
for
the
first
time
establish
performance
standards
applicable
to
Hg
emissions,
and
those
standards
will
require
significant
reductions
in
the
levels
of
Hg
emissions.
Such
reductions
will
provide
greater
protection
to
Tribal
fish
resources
than
would
otherwise
be
available.
Acting
to
provide
such
heightened
protection
is
consistent
with
both
the
statute
and
the
Federal
trust
responsibility.

Moreover,
the
commenters
offer
no
specific
evidence
that
the
Hg
emissions
reductions
from
this
regulation
will
not
adequately
protect
Tribal
health.
Their
main
contention
is
that
the
regulatory
approach
set
forth
in
an
earlier
EPA
proposal
would
have
produced
a
90
percent
reduction
in
Hg
emissions
and
that
any
smaller
reduction
is,
therefore,
inadequate.
That
contention
rests
on
a
misconception
of
an
earlier
Federal
Register
Notice,
which
proposed
a
finding,
but
did
not
contain
any
specific
proposal
for
Hg
emissions
regulations,
and,
therefore,
did
not
provide
for
any
percentage
of
reduction.
EPA
has
never
proposed
any
such
rule.
EPA
believes
that
this
regulation
will
adequately
protect
Tribal
health.

The
commenters
also
argue
that
EPA
has
not
adequately
considered
the
significance
of
Tribal
fish
consumption
patterns,
specifically
the
fact
that
Tribal
fishers
consume
more
fish
than
the
general
population.
That
comment
is
misplaced.
As
described
in
more
detail
elsewhere
in
this
document,
EPA
carefully
analyzed
available
information
on
fish
consumption
by
Tribal
members
and
other
sub­
populations,
and
determined
how
to
use
the
available
data
most
appropriately.
One
basis
for
EPA's
analysis
was
a
study
of
tribal
fish
consumption
in
one
region
to
model
consumption
by
other
Tribes
as
well
as
other
subpopulations.
EPA's
approach
was
to
identify
areas
where
the
effects
of
Hg
deposition
from
utility
emissions
had
the
greatest
effects.
EPA
then
compared
those
high­
deposition
areas
with
locations
with
high
Tribal
populations
to
assess
the
areas
of
greatest
potential
risk
to
Tribes.
That
analysis
found
that
very
few
areas
where
Native
Americans
live
corresponds
with
high
residual
Hg
deposition
caused
by
utilities.
It
found
further,
that
the
standards
established
in
the
regulation
will
significantly
reduce
risks
to
tribal
members.

Finally,
as
discussed
in
the
preamble
to
the
regulation,
this
regulation
establishes
a
capand
trade
program
for
Indian
country.

As
part
of
its
analysis
of
the
this
final
rule,
EPA
has
estimated
the
some
of
the
health
9­
302
benefits
of
reducing
Hg
from
utilities.
At
this
time
EPA
is
only
able
to
provide
quantative
estimates
of
the
benefits
of
reducing
neurological
impacts
of
exposure
to
MeHg
for
a
portion
of
the
U.
S.
population.
This
population
covers
people
who
recreationally
catch
and
consume
freshwater
fish.
The
RIA
for
this
rule
contains
this
analysis
in
Chapter
11.
As
part
of
its
assessment,
EPA
provides
estimates
for
the
benefits
of
this
rulemaking
to
subsistence
fishers,
including
case
study
examples
of
the
benefits
to
the
some
members
of
the
Chippewa
Tribe,
the
Hmong,
and
low
income
fishers.

Comment
One
commenter
(
OAR­
2002­
0056­
5492)
made
the
following
recommendations
to
the
EPA
regarding
development
of
a
final
proposal
for
Hg
control:

°
Carbon
Injection
(
ACI)
is
maturing
quickly.
Using
a
methodology
that
says
subbituminous
coal
needs
a
credit
multiplier
or
higher
emissions,
results
in
fuel
bias
against
bituminous
coal
and
the
states
that
produce
bituminous
coal.

°
The
commenter
believes
that
wet
ESPs
and
SCRs
remove
more
oxidized
Hg
than
EPA
results
show.

°
The
western
coal
state
congressional
delegations,
who
are
saying
that
technology
will
not
be
available
to
remove
Hg
from
their
sub­
bituminous
coal,
are
ignoring
the
benefits
America
has
already
received
from
investments
in
developing
clean
coal
technology
for
Hg
removal
and
punishing
bituminous
coal
users.

°
A
MACT
standard
should
be
fuel
neutral,
i.
e.,
no
separate
standards
for
different
coal
ranks.

°
A
fuel­
neutral
MACT
of
3.0
lbs
Hg/
TBtu
or
less
for
existing
EGUs
will
reduce
Hg
emissions
to
less
than
34
tons/
year.

°
A
MACT
standard
should
incorporate
an
alternative
method
to
calculate
plant
Hg
emissions
limits
based
on
a
percent
reduction
from
the
raw
coal
as
mined.
Such
an
alternative
would
provide
some
amount
of
relief
for
those
coals
with
unusually
high
Hg
content
while
still
achieving
meaningful
reductions.

°
Under
the
alternative
cap
and
trade
proposals,
implementation
dates
should
be
adjusted
to
coincide
with
other
regulatory
actions,
including
the
Clean
Air
Interstate
Rule
and
multi­
pollutant
strategies
such
as
Clear
Skies.

°
A
cap
and
trade
rule
should
not
include
Fuel
Adjustment
Factors.

°
A
cap
and
trade
rule
should
address
so­
called
"
hot
spots"
that
could
result
from
allowance
trading.
9­
303
The
commenter
appreciated
the
opportunity
to
provide
comments
to
the
U.
S.
EPA
regarding
the
proposed
Hg
regulations.
The
commenter
would
be
pleased
to
provide
additional
information
and
are
willing
to
meet
with
the
U.
S.
EPA
regarding
our
statement.

Response:

EPA
has
examined
the
commenter's
concerns
in
context
of
the
final
rulemaking.
EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112.

EPA
appreciates
the
commenter's
input
to
the
record
on
the
status
of
control
technologies.
The
Agency's
position
on
the
state
of
Hg
technology
is
contained
in
the
EPA
'
s
Office
of
Research
and
Development
white
paper
(
see
Control
of
Emissions
from
Coal­
Fired
Electric
Utility
Boilers:
An
Update,
EPA/
Office
of
Research
and
Development,
March
2005).

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
reports
key
public
power
concerns
in
response
to
the
EPA
NODA.
This
commenter
prefers
a
cap
and
trade
approach
to
controlling
Hg
without
disadvantaging
smaller
utilities
with
only
one
generating
unit
or
few
fuel
options.
The
commenter
endorses
comments
from
UARG
and
PERI.

The
commenter
continues
to
support
an
exemption
for
small
units
and
requests
that
EPA
streamline
the
monitoring
requirements
for
small
and/
or
exempt
units
regardless
of
decision
to
use
cap
and
trade
approach
(
Sec.
111
or
112
(
n)
(
1)
(
A)
or
MACT
Approach:

The
commenter
believes
that
EPA
should
provide
for
alternative
treatment
for
small
utilities
~
50
MW.
(
Questions
5
&
6)

With
regard
to
de
minimis
threshold,
this
commenter
continues
to
support
EPA's
suggested
exemption
for
units
that
emit
less
than
25
pounds
of
Hg
annually,
and
encourages
EPA
to
extend
the
exemption
to
units
that
emit
up
to
50
pounds
a
year.
EPA's
re­
examination
of
the
benefits
associated
with
the
Utility
MACT
in
the
NODA
lends
further
support
to
an
exemption.
As
EPA
notes
in
the
NODA,
there
are
open
issues
regarding
the
benefits
of
the
total
Hg
reductions
being
proposed
in
the
Utility
MACT
for
all
electric
utility
steam
generating
units
in
the
U.
S.
This
issue
is
even
more
relevant
to
the
minimal
emissions
from
small
units,
where
the
costs
of
monitoring
and
compliance
are
clearly
significant,
but
the
benefits
are
small
and
uncertain.
For
this
reason,
and
the
others
set
out
in
the
commenter's
previous
comments
in
this
rulemaking,
including
the
likelihood
that
many
of
the
commenter's
smaller
units
will
be
forced
to
close
under
the
pressure
of
the
Utility
MACT
rule
and
the
Clean
Air
Interstate
Rule
(
CAIR
rule),
and
the
impacts
of
that
on
the
national
transmission
grid),
the
commenter
requests
that
EPA
exempt
these
9­
304
small
units
from
the
Utility
MACT.

Response:

As
discussed
above
and
in
the
final
rule
preamble
(
section
IV.
D.
3.
iv),
EPA
is
not
finalizing
a
low­
emitter
exclusion
and
EPA
recommends
States
address
small
business
entities
through
the
allocation
process.

Comment:

With
regard
to
monitoring
for
smaller
utilities,
one
commenter
(
OAR­
2002­
0056­
5571)
requests
that
EPA
also
simplify
monitoring
for
smaller
and/
or
exempt
units.
Monitoring
costs
present
a
significant
compliance
cost,
particularly
for
small
units,
and
one
that
is
unwarranted
in
light
of
the
minimal
risk
that
these
units
pose.
For
an
exempt
unit,
the
monitoring
costs
to
prove
that
a
unit
is
exempt
could
prove
to
be
as
significant
as
the
costs
of
compliance
with
the
rule,
thereby
defeating
the
purpose
of
the
exemption.
EPA
estimates
the
capital
cost
of
Hg
CEMS
range
from
$
95,000
to
$
135,000.
Annual
operating
and
maintenance
costs
are
estimated
to
range
between
$
45,000
to
$
65,000.
Under
the
upper
end
of
the
range,
the
first
year's
monitoring
cost,
equal
to
$
200,000
per
year,
would
be
in
the
same
range
as
controlling
for
Hg
through
allowance
purchases
($
20,000)
for
a
unit
that
emitted,
as
many
of
the
commenter's
members
do,
about
10
pounds
per
year.

The
commenter
notes
that
not
only
are
the
monitoring
costs
for
these
small
units
enormous,
but
they
are
particularly
inappropriate
in
light
of
the
minimal
risks
presented
by
small
units.
Units
subject
to
a
50
pound
exemption
account
for
a
small
fraction
of
the
Hg
emitted
in
the
U.
S.
The
total
Hg
emissions
from
these
units
are
just
over
6
tons
per
year,
or
less
than
15
percent
of
the
Hg
emitted
from
all
coal­
fired
power
plants.
The
emissions
for
all
units
less
than
25
pounds
are
less
than
2
tons
per
year,
or
less
than
5
percent
of
total
Hg
emissions.
Further,
as
EPA
notes
in
the
NODA,
there
are
open
issues
regarding
the
benefits
of
the
total
Hg
reductions
from
all
utilities
in
the
U.
S.
discussed
in
the
Utility
MACT.
This
raises
serious
questions
about
the
even
smaller
and
less
certain
benefits
of
regulating
small
emitters,
particularly
when
monitoring
and
compliance
costs
for
the
small
emitters
are
substantial.

The
commenter
recommends
that
for
these
small
and/
or
exempt
units,
EPA
adopt
the
Hg
monitoring
requirements
that
have
already
been
developed
for
small
units
in
the
context
of
another
MACT
rulemaking.
The
MACT
for
Industrial,
Commercial
and
Institutional
Boilers
and
Process
Heaters
applies
to
utility
boilers
that
generate
equal
to
or
less
than
25
MW
(
as
well
as
industrial
units
that
generate
less
than
25
MW)
and
includes
requirements
for
Hg
testing.
See
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial,
Commercial,
and
Institutional
Boilers
and
Process
Heaters,
69
Fed.
Reg.
55,218
(
September
13,
2004).
These
testing
requirements
are
particularly
appropriate
for
the
smaller
units
in
the
Utility
MACT,
which
have
significant
similarities
to
the
units
in
the
Boiler
MACT,
including
small
size
and
limited
emissions.
9­
305
The
monitoring
requirements
for
the
Boiler
MACT
include
initial
and
annual
stack
tests
(
using
EPA
method
29,
Part
60,
Appendix
A
or
ASTM
D6784­
02),
or,
in
the
alternative,
fuel
testing
(
using
ASTM
D3684­
01,
see
Table
6
attached).
The
general
monitoring
requirements
from
the
Industrial
Boiler
MACT
are
attached
in
Appendix
II
to
these
comments.
These
monitoring
requirements,
including
the
continuous
compliance
requirements,
are
more
appropriate
to
small
and/
or
exempt
units
in
the
Utility
MACT
rule
than
the
significant
costs
associated
with
CEMS,
while
ensuring
that
these
units
continue
to
qualify
as
small
and/
or
exempt.

If
EPA
determines
that
Boiler
MACT
monitoring
requirements
cannot
be
used
of
Utility
MACT,
the
commenter
also
encourages
the
EPA
to
adopt
phased­
in
monitoring
requirements
for
small
and/
or
exempt
units.
There
are
still
significant
uncertainties
associated
with
the
current
monitoring
technology.
These
technology
issues
will
present
a
particular
hardship
on
municipally
owned
utilities.
Smaller
municipal
utilities
face
substantial
challenges
because
they
lack
the
resources
to
address
these
monitoring
issues
and
are
unable
to
get
priority
in
hiring
consultants.
EPA
should
delay
the
Hg
monitoring
requirements
for
exempt
and/
or
small
sources
until
at
least
2010
when
Hg
monitoring
technology
may
be
more
fully
developed,
demonstrated,
and
less
expensive.

Response:

As
discussed
above
and
in
the
final
rule
preamble
(
section
IV.
D.
3.
iv),
EPA
is
not
finalizing
a
low­
emitter
exclusion
and
EPA
recommends
States
address
small
business
entities
through
the
allocation
process.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
believed
that
should
a
cap­
and­
trade
program
be
implemented,
EPA
has
proposed
an
exemption
for
small
emitters.
It
suggests
an
exemption
for
units
that
emit
25
pounds
or
less.
According
to
EPA's
data,
this
would
apply
to
3.9
percent
of
emissions
nationwide.
The
commenter
believed
that
EPA
should
restyle
the
small
emitter
exemption
so
that
it
applies
to
existing
units
at
small
plants
emitting,
with
a
minimum
of
25
pounds
on
a
per
unit
basis.

Response:

As
discussed
above
and
in
the
final
rule
preamble
(
section
IV.
D.
3.
iv),
EPA
is
not
finalizing
a
low­
emitter
exclusion
and
EPA
recommends
States
address
small
business
entities
through
the
allocation
process.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
urges
the
EPA
to
also
consider
other
de
minimis
options
offered
by
public
power
communities
(
including
the
>
95
pound
plant
wide
suggestion
for
community
utilities
that
meet
the
SBREFA
definition).
Earlier
the
commenter
provided
9­
306
references
to
the
UMRA,
Regulatory
Flexibility
Act,
SBREFA
Act
of
1996
and
Executive
Order
12866
that
would
justify
making
some
practical
decisions
about
a
de
minimis
exemption.
Whatever
de
minimis
level
the
EPA
ultimately
sets
in
the
final
rule.
The
commenter
does
not
believe
that
this
de
minimis
should
not
subject
the
larger
units/
plants
to
more
stringent
cap
levels.

Response:

As
discussed
above
and
in
the
final
rule
preamble
(
section
IV.
D.
3.
iv),
EPA
is
not
finalizing
a
low­
emitter
exclusion
and
EPA
recommends
States
address
small
business
entities
through
the
allocation
process.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
believes
that
the
EPA's
final
rule
should
emphatically
state
that
the
smaller
utility
systems
(
particularly
those
that
meet
the
SBREFA
definition)
should
be
able
to
work
with
their
state
agencies
and
permit
writers
to
determine
the
most
practical
and
reliable
method
to
perform
monitoring
functions
at
lowest
cost
(
considering
capital
expense,
operating
and
maintenance,
and
on­
going
staff
training
expenses).
Many
public
power
utilities
simply
don't
have
the
personnel
skills
to
perform
these
highly
sophisticated
monitoring
runs.
Also
many
public
power
communities
are
two
hours
away
from
major
metropolitan
areas
or
airport
hubs
so
that
frequent
visits
by
CEM
manufacturers,
vendors,
contractors,
or
service
personnel
would
be
prohibitively
expensive.

Response:

As
discussed
above
and
in
the
final
rule
preamble
(
section
IV.
D.
3.
iv),
EPA
is
not
finalizing
a
low­
emitter
exclusion
and
EPA
recommends
States
address
small
business
entities
through
the
allocation
process.

Comment:

One
commenter
(
OAR­
2002­
0056­
5571)
strongly
urges
the
U.
S.
EPA
to
encourage
states
to
work
with
the
smaller
Hg
emitters
to
allow
creative
Hg
reduction/
mitigation/
removal
or
prevention
projects.
Holland
Board
of
Public
Works
is
a
municipal
utility
with
approximately
30,000
households
in
Michigan.
Earlier
in
2004
the
municipal
utility
initiated
a
community
program
to
encourage
the
voluntary
return
of
Hg
thermometers
to
reduce
Hg
from
household
environments,
landfills
and
the
wastewater
system.
The
utility
provided
digital
thermometers
to
those
who
returned
a
glass
thermometer
containing
Hg
or
other
Hg­
containing
items.
In
the
span
of
a
few
months
the
Holland
Board
of
Public
Works
collected
28
pounds
of
Hg
through
this
program
in
addition
to
working
with
commercial
industrial
customers.
Comparatively,
the
Holland
Board
of
Public
Works
emits
approximately
8
pounds
of
total
Hg
annually
through
combined
oil,
coal
and
gas
generation.
The
commenter
believes
that
the
EPA
and
states
should
encourage
alternative
methods
like
this
innovative
method
to
reduce
Hg
that
are
cost
effective
in
the
final
rule.
The
Clean
Air
Act
authorized
the
EPA
to
consider
work
practices
and
other
9­
307
alternatives
when
they
are
demonstrated
to
be
effective
and
can
be
proven.
The
commenter
strongly
urges
the
EPA
to
allow
state
agencies
to
work
with
smaller
emitters
on
this
type
of
alternative
to
MACT
if
the
EPA
promulgates
a
MACT
standard
or
if
it
authorizes
a
cap
and
trade
program
that
a
state
declines
to
opt
into.

Response:

As
discussed
above
and
in
the
final
rule
preamble
(
section
IV.
D.
3.
iv),
EPA
is
not
finalizing
a
low­
emitter
exclusion
and
EPA
recommends
States
address
small
business
entities
through
the
allocation
process.

Comment:

The
commenter
(
OAR­
2002­
0056­
5455)
also
took
issue
with
the
modeling
performed
in
the
analysis.
The
commenter
does
not
believe
the
science
of
modeling
has
reached
a
point
where
it
can
accurately
be
used
for
Hg
transport
and
deposition
due
to
the
lack
of
understanding
about
dry
deposition.
Few
deposition
monitors
exist
in
Indian
Country
so
it's
very
hard
to
say
how
much
wet
or
dry
deposition
is
occurring
in
these
areas
15.
Based
on
this
concern,
the
commenter
believed
it
is
reckless
to
propose
a
cap
and
trade
program
relying
on
the
results
of
EPA's
models.
It
is
better
to
err
on
the
side
of
caution
than
to
be
wrong
in
such
an
important
matter.
To
account
for
the
lack
of
confidence
in
the
models,
EPA
should
abandon
its
idea
of
cap
and
trade
and
stick
to
a
MACT
standard.

The
commenter
believed
that
the
air
emission
inventories
used
in
EPA's
analysis
probably
underestimated
the
amount
of
Hg
emitted
from
some
sources,
such
as
miscellaneous
product
disposal.
EPA
has
used
the
best
information
it
has
available,
but
it
should
leave
a
margin
of
safety
to
account
for
inaccuracies.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112.

Comment:

The
commenter
(
OAR­
2002­
0056­
5551)
stated
that
firstly,
standards
for
controlling
HAPs
from
coal
fired
power
plants
must
follow
the
requirements
of
Section
112
of
the
Clean
Air
Act.
The
commenter
noted
that
for
existing
power
plants,
each
MACT
limit
must
be
at
least
as
stringent
as
the
limit
which
is
achievable
by
the
average
of
the
best
controlled
12
percent
of
similar
units
for
which
there
is
data.
The
commenter
noted
that
this
is
commonly
referred
to
as
the
MACT
floor.
The
commenter
stated
that
the
standards
should
be
more
stringent
if
justified
by
9­
308
cost,
benefit
and
feasibility.
According
to
the
commenter,
hence,
the
NODA
information
on
costs
and
benefits
is
primarily
relevant
for
setting
more
stringent
standards
than
the
MACT
floor.
The
commenter
believed
that
the
NODA
is
useful
for
setting
MACT
standards
better
than
the
MACT
floor
for
subbituminous
and
lignite
coal
combustion,
if
a
coal
neutral
standard
is
not
set.
The
commenter
stated
that,
however,
information
on
costs
and
benefits
are
irrelevant
to
the
setting
of
the
MACT
floor.

While
the
commenter
believed
that
the
choice
of
3
mg
per
MWh
or
90
percent
control,
annual
averages,
is
an
appropriate
MACT
standard
for
all
coals,
the
commenter
noted
that
EPA
may
choose
to
set
MACT
limits
by
principle
coal
type,
i.
e.,
bituminous,
subbituminous,
and
lignite.
In
such
an
event,
the
commenter
recommended
that
EPA
set
better
than
the
MACT
floor
limits
for
subbituminous
and
lignite
coals
in
view
of
the
generally
limited
control
systems
currently
in
place
for
these
coals
and
the
recent
success
in
controlling
Hg
from
these
coals
using
halogenated
activated
carbon
injection.
The
commenter
stated
that
the
rate
component
of
the
standard
should
remain
the
same
as
bituminous
coal
to
facilitate
compliance
determination
for
blended
coals.
The
commenter
added
that,
alternatively,
blended
coals
should
be
subject
to
the
most
stringent
rate
for
the
coals
being
blended.
The
commenter
stated
that
the
control
efficiency
component
of
a
MACT
limit
for
subbituminous
and
lignite
coals
could
be
somewhat
less
stringent
than
for
bituminous
coals,
in
view
of
the
somewhat
lower
Hg
content
of
these
coals
and
the
lesser
amount
of
data
for
control
of
Hg
from
these
coals.
According
to
the
commenter,
3
mg
per
MWhr
or
80
percent
control
would
be
a
reasonable
MACT
standard
for
these
coals
at
this
time.

Response:

EPA
is
finalizing
a
cap­
and­
trade
approach
under
section
111.
Please
see
the
Revision
of
December
2000
Regulatory
Finding
on
the
Emissions
of
Hazardous
Air
Pollutants
from
Electric
Utility
Steam
Generating
Units
and
the
Removal
of
Coal­
and
Oil­
fired
Electric
Utility
Steam
Generating
Units
from
the
Section
112(
c)
List
for
a
discussion
of
the
Agency's
rationale
for
not
proceeding
under
Section
112.