Document ID: EPA-HQ-OAR-2004-0004-0063
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-04-01T05:00Z

6560­
50­
P
ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Part
63
[
EPA­
HQ­
OAR­
2004­
0004,
FRL­
]

RIN
2060­
AK16
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial
Process
Cooling
Towers
AGENCY:
Environmental
Protection
Agency
(
EPA).

ACTION:
Final
rule;
amendment.

SUMMARY:
On
September
8,
1994,
we
promulgated
national
emission
standards
for
hazardous
air
pollutants
for
industrial
process
cooling
towers.
The
rule
prohibits
the
use
of
chromium­
based
water
treatment
chemicals
that
are
known
or
suspected
to
cause
cancer
or
have
a
serious
health
or
environmental
effect.

Section
112(
f)(
2)
of
the
Clean
Air
Act
directs
us
to
assess
the
risk
remaining
(
residual
risk)
after
the
application
of
national
emission
standards
for
hazardous
air
pollutants
and
to
promulgate
more
stringent
standards,
if
warranted,
to
provide
an
ample
margin
of
safety
to
protect
public
health
or
prevent
adverse
environmental
effect.

Also,
section
112(
d)(
6)
of
the
Clean
Air
Act
requires
us
to
review
and
revise
the
standards,
as
necessary
at
least
every
8
years,
taking
into
account
developments
in
practices,

processes,
and
control
technologies.
On
October
24,
2005,
2
based
on
the
findings
from
our
residual
risk
and
technology
review,
we
proposed
no
further
action
to
revise
the
standards
and
requested
public
comment.
Today's
final
action
amends
the
applicability
section
of
the
rule
in
response
to
public
comments
received
on
the
proposed
action.

The
final
amendment
provides
that
sources
that
are
operated
with
chromium­
based
water
treatment
chemicals
are
subject
to
this
standard;
other
industrial
process
cooling
towers
are
not
covered.

EFFECTIVE
DATE:
[
INSERT
DATE
OF
PUBLICATION
OF
THE
FINAL
AMENDMENT
IN
THE
FEDERAL
REGISTER].

ADDRESSES:
EPA
has
established
a
docket
for
this
action
under
Docket
ID
No.
EPA­
HQ­
OAR­
2004­
0004.
All
documents
in
the
docket
are
listed
on
the
www.
regulations.
gov
web
site.

Although
listed
in
the
index,
some
information
is
not
publicly
available,
i.
e.,
confidential
business
information
or
other
information
whose
disclosure
is
restricted
by
statute.
Certain
other
material,
such
as
copyrighted
material,
is
not
placed
on
the
Internet
and
will
be
publicly
available
only
in
hard
copy
form.
Publicly
available
docket
materials
are
available
either
electronically
through
www.
regulations.
gov
or
in
hard
copy
at
the
national
emission
standards
for
hazardous
air
pollutants
(
NESHAP)
for
Industrial
Process
Cooling
Towers
(
IPCT)
Docket,
EPA/
DC,
3
Docket
ID
No.
EPA­
HQ­
OAR­
2004­
0004,
EPA
West,
Room
B102,

1301
Constitution
Ave.,
NW,
Washington,
DC.
The
Public
Reading
Room
is
open
from
8:
30
a.
m.
to
4:
30
p.
m.,
Monday
through
Friday,
excluding
legal
holidays.
The
telephone
number
for
the
Public
Reading
Room
is
(
202)
566­
1744,
and
the
telephone
number
for
the
Air
Docket
Center
is
(
202)
566­

1742.

FOR
FURTHER
INFORMATION
CONTACT:
For
questions
about
the
final
action,
contact
Mr.
Phil
Mulrine,
U.
S.
EPA,
Office
of
Air
Quality
Planning
and
Standards,
Sector
Policies
and
Programs
Division,
Metals
and
Minerals
Group
(
D243­
02),

Research
Triangle
Park,
North
Carolina
27711;
telephone
number:
(
919)
541­
5289;
fax
number:
(
919)
541­
5450;
e­
mail
address:
mulrine.
phil@
epa.
gov.
For
questions
on
the
residual
risk
analysis,
contact
Mr.
Scott
Jenkins,
U.
S.
EPA,

Office
of
Air
Quality
Planning
and
Standards,
Health
and
Environmental
Impacts
Division,
Sector
Based
Assessment
Group
(
C539­
02),
Research
Triangle
Park,
North
Carolina
27711,
telephone
number:
(
919)
541­
1167,
fax
number:
(
919)

541­
0840,
e­
mail
address:
jenkins.
scott@
epa.
gov.

SUPPLEMENTARY
INFORMATION:

Regulated
Entities.
The
regulated
categories
and
entities
affected
by
the
NESHAP
include:

Category
NAICS
Examples
of
regulated
4
code1
entities
Industry.............
324110
325181
325120
325131
325188
325191
325311
325312
325314
325320
325520
325920
325910
325182
325998
331111
331411
331419
327211
327213
327212
312221
312229
312229
326211
313311
313311
313312
IPCT
located
at
major
sources,
including
petroleum
refineries,
chemical
manufacturing
plants,
primary
metals
processing
plants,
glass
manufacturing
plants,
tobacco
products
manufacturing
plants,
rubber
products
manufacturing
plants,
and
textile
finishing
plants.

Federal
government
Not
affected.

State,
local,
tribal
government
Not
affected.
1
North
American
Industry
Classification
System.

This
table
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
likely
to
be
affected
by
the
NESHAP.
To
determine
whether
your
facility
would
be
affected
by
the
NESHAP,
you
should
examine
the
applicability
criteria
in
40
CFR
63.400(
a)
of
subpart
Q
(
IPCT
NESHAP).
If
you
have
any
questions
regarding
the
5
applicability
of
the
NESHAP
to
a
particular
entity,
contact
either
the
air
permit
authority
for
the
entity
or
your
EPA
regional
representative
as
listed
in
40
CFR
63.13
of
subpart
A
(
General
Provisions).

Worldwide
Web
(
WWW).
In
addition
to
being
available
in
the
docket,
an
electronic
copy
of
today's
final
action
will
also
be
available
on
the
WWW
through
the
Technology
Transfer
Network
(
TTN).
Following
the
Administrator's
signature,
a
copy
of
the
final
action
will
be
posted
on
the
TTN's
policy
and
guidance
page
for
newly
proposed
or
promulgated
rules
at:
www.
epa.
gov/
ttn/
oarpg.
The
TTN
provides
information
and
technology
exchange
in
various
areas
of
air
pollution
control.

Judicial
Review.
Under
section
307(
b)(
1)
of
the
Clean
Air
Act
(
CAA),
judicial
review
of
the
final
action
is
available
only
by
filing
a
petition
for
review
in
the
U.
S.
Court
of
Appeals
for
the
District
of
Columbia
Circuit
by
[
INSERT
DATE
60
DAYS
AFTER
PUBLICATION
OF
THE
FINAL
AMENDMENT
IN
THE
FEDERAL
REGISTER].
Under
section
307(
d)(
7)(
B)
of
the
CAA,

only
an
objection
to
the
final
action
amendment
that
was
raised
with
reasonable
specificity
during
the
period
for
public
comment
can
be
raised
during
judicial
review.

Moreover,
under
section
307(
b)(
2)
of
the
CAA,
the
requirements
established
by
the
final
action
may
not
be
6
challenged
separately
in
any
civil
or
criminal
proceedings
brought
by
EPA
to
enforce
the
requirements.

Outline.
The
information
presented
in
this
preamble
is
organized
as
follows:

I.
Background
A.
What
is
the
statutory
authority
for
this
action?
B.
What
did
the
IPCT
NESHAP
accomplish?
C.
What
were
the
conclusions
of
the
residual
risk
assessment?
D.
What
were
the
conclusions
of
the
technology
review?
E.
What
was
the
proposed
action?
II.
Today's
Action
A.
What
is
today's
final
action?
B.
What
comments
were
received
on
the
proposed
action?
III.
Statutory
and
Executive
Order
Reviews
A.
Executive
Order
12866:
Regulatory
Planning
and
Review
B.
Paperwork
Reduction
Act
C.
Regulatory
Flexibility
Act
D.
Unfunded
Mandates
Reform
Act
E.
Executive
Order
13132:
Federalism
F.
Executive
Order
13175:
Consultation
and
Coordination
with
Indian
Tribal
Governments
G.
Executive
Order
13045:
Protection
of
Children
from
Environmental
Health
and
Safety
Risks
H.
Executive
Order
13211:
Actions
Concerning
Regulations
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
I.
National
Technology
Transfer
and
Advancement
Act
J.
Congressional
Review
Act
I.
Background
A.
What
is
the
statutory
authority
for
this
action?

Section
112
of
the
CAA
establishes
a
comprehensive
regulatory
process
to
address
hazardous
air
pollutants
(
HAP)

from
stationary
sources.
In
implementing
this
process,
we
have
identified
categories
of
sources
emitting
one
or
more
of
the
HAP
listed
in
the
CAA,
and
industrial
process
cooling
7
towers
are
identified
as
one
such
source
category.
Section
112(
d)
requires
us
to
promulgate
national
technology­
based
emission
standards
for
sources
within
those
categories
that
emit
or
have
the
potential
to
emit
any
single
HAP
at
a
rate
of
10
tons
or
more
per
year
or
any
combination
of
HAP
at
a
rate
of
25
tons
or
more
per
year
(
known
as
major
sources),

as
well
as
for
certain
area
sources
emitting
less
than
those
amounts.
These
technology­
based
NESHAP
must
reflect
the
maximum
reductions
of
HAP
achievable
(
after
considering
cost,
energy
requirements,
and
non­
air
health
and
environmental
impacts)
and
are
commonly
referred
to
as
maximum
achievable
control
technology
(
MACT)
standards.

In
what
is
referred
to
as
the
technology
review,
we
are
required
under
section
112(
d)(
6)
of
the
CAA
to
review
these
technology­
based
standards
no
less
frequently
than
every
8
years.
Further,
if
we
conclude
that
a
revision
is
necessary,
we
have
the
authority
to
revise
these
standards,

taking
into
account
"
developments
in
practices,
processes,

and
control
technologies."

The
residual
risk
review
is
described
in
section
112(
f)

of
the
CAA.
Section
112(
f)(
2)
requires
us
to
determine
for
each
section
112(
d)
source
category,
except
area
source
categories
for
which
we
issued
a
generally
available
control
technology
standard,
whether
the
NESHAP
protects
public
8
health
with
an
ample
margin
of
safety.
If
the
NESHAP
for
HAP
"
classified
as
a
known,
probable,
or
possible
human
carcinogen
do
not
reduce
lifetime
excess
cancer
risks
to
the
individual
most
exposed
to
emissions
from
a
source
in
the
category
or
subcategory
to
less
than
one
in
one
million,"
we
must
decide
whether
additional
reductions
are
necessary
to
provide
an
ample
margin
of
safety.
As
part
of
this
decision,
we
may
consider
costs,
technological
feasibility,

uncertainties,
or
other
relevant
factors.
We
must
determine
whether
more
stringent
standards
are
necessary
to
prevent
adverse
environmental
effect
(
defined
in
CAA
section
112(
a)(
7)
as
"
any
significant
and
widespread
adverse
effect,

which
may
reasonably
be
anticipated
to
wildlife,
aquatic
life,
or
other
natural
resources,
including
adverse
impacts
on
populations
of
endangered
or
threatened
species
or
significant
degradation
of
environmental
quality
over
broad
areas."),
but
in
making
this
decision
we
must
consider
cost,

energy,
safety,
and
other
relevant
factors.

B.
What
did
the
IPCT
NESHAP
accomplish?

On
September
8,
1994
(
59
FR
46350),
we
promulgated
the
IPCT
NESHAP
and
required
existing
sources
to
comply
with
the
rule
requirements
by
March
8,
1996.

Cooling
towers
are
devices
that
are
used
to
remove
heat
from
a
cooling
fluid,
typically
water,
by
contacting
the
9
fluid
with
ambient
air.
The
IPCT
source
category
includes
cooling
towers
that
are
used
to
remove
heat
that
is
produced
as
an
input
or
output
of
chemical
or
industrial
processes.

The
IPCT
source
category
also
includes
cooling
towers
that
cool
industrial
processes
in
combination
with
heating,

ventilation,
and
air
conditioning
(
HVAC)
systems.
The
IPCT
NESHAP
applies
specifically
to
IPCT
that
use
chromium­
based
water
treatment
chemicals
and
are
located
at
major
sources
of
HAP
emissions.
Standards
to
control
chromium
emissions
from
cooling
towers
that
cool
HVAC
systems
exclusively
(
comfort
cooling
towers)
were
promulgated
under
section
6
of
the
Toxic
Substances
Control
Act
(
55
FR
222,
January
3,

1990).

The
primary
industries
that
use
IPCT
include
petroleum
refineries,
chemical
manufacturing
plants,
primary
metals
processing
plants,
glass
manufacturing
plants,
rubber
products
manufacturing
plants,
tobacco
products
manufacturing
plants,
and
textile
manufacturing
plants.

When
the
IPCT
NESHAP
were
promulgated,
we
estimated
that
there
were
approximately
6,945
IPCT
located
at
these
plants
nationwide,
and
that
approximately
260
of
these
IPCT
used
chromium­
based
water
treatment
chemicals.
We
estimated
that
the
IPCT
NESHAP
would
reduce
emissions
of
chromium
compounds
from
these
facilities
by
22.7
megagrams
per
year
(
Mg/
yr)
(
25
10
tons
per
year
(
tpy))
by
prohibiting
the
use
of
chromiumbased
water
treatment
chemicals
in
IPCT.
In
addition,
we
estimated
that
the
NESHAP
would
prevent
emissions
of
1.6
Mg/
yr
(
1.8
tpy)
of
chromium
compounds
from
the
870
new
IPCT
projected
by
the
5th
year
of
the
standards
(
1998).

When
the
NESHAP
were
promulgated,
we
had
no
information
that
indicated
that
HAP
other
than
chromium
compounds
were
emitted
from
IPCT.
Consequently,
we
did
not
address
emissions
of
other
HAP
in
the
IPCT
NESHAP.

C.
What
were
the
conclusions
of
the
residual
risk
assessment?

As
required
by
section
112(
f)(
2)
of
the
CAA,
we
prepared
a
risk
assessment
to
determine
the
residual
risk
posed
by
IPCT
after
implementation
of
the
NESHAP.
To
evaluate
the
residual
risk
for
the
IPCT
source
category,
we
identified
the
HAP
emitted
from
IPCT
and,
as
a
discretionary
matter
in
this
instance,
estimated
worst­
case
emission
rates
for
each
of
those
HAP.
These
worst­
case
emission
rates
were
used,
along
with
facility
parameters
representing
an
actual
facility,
to
perform
the
risk
assessment.

Because
the
IPCT
NESHAP
prohibits
the
use
of
chromiumbased
water
treatment
chemicals
in
IPCT,
we
believe
that
chromium
compound
emissions
from
IPCT
have
been
eliminated
by
the
NESHAP.
In
assessing
the
residual
risk
for
the
11
source
category,
however,
we
also
considered
emissions
of
other
HAP
from
IPCT.

In
the
absence
of
process
leaks
or
malfunctions,
the
chemical
species
that
are
emitted
from
IPCT
consist
of
the
naturally­
occurring
constituents
of
the
cooling
water
and
any
substances
that
are
added
to
the
cooling
water.
To
determine
what
other
HAP
may
be
emitted
from
IPCT,
we
first
contacted
suppliers
of
cooling
water
treatment
chemicals
for
information
on
cooling
water
additives
that
either
contain
HAP
or
form
HAP,
which
could
be
emitted
from
IPCT.
Then,
we
conducted
a
literature
search
for
information
on
emissions
from
cooling
towers.
The
information
collected
from
the
water
treatment
chemical
suppliers
and
through
the
literature
search
indicated
that
some
biocides
used
to
treat
industrial
cooling
water
either
contain
HAP
or
form
HAP
that
can
be
emitted
from
IPCT.
These
HAP
include
chloroform,

methanol,
and
ethylene
thiourea.

Industrial
process
cooling
towers
typically
use
one
and
not
all
of
the
biocides
that
release
the
three
listed
HAP
at
any
given
time.
Therefore,
IPCT
emit
no
more
than
one
of
the
three
listed
HAP.
We
estimated
worst­
case
emission
rates
for
chloroform,
methanol,
and
ethylene
thiourea
based
on
the
range
of
concentrations
of
these
constituents
in
cooling
water
and
the
model
plants
developed
for
the
IPCT
12
NESHAP.
We
used
these
emission
rates
to
model
exposure
concentrations
surrounding
those
sources,
calculated
the
risk
of
possible
chronic
cancer
and
noncancer
health
effects,
evaluated
whether
acute
exposures
might
exceed
relevant
health
thresholds,
and
investigated
human
health
multipathway
and
ecological
risks.

Consistent
with
the
tiered
modeling
approach
described
in
the
"
Residual
Risk
Report
to
Congress"
(
EPA­
453/
R­
99­

001),
the
risk
assessment
for
this
source
category
started
with
a
simple
assessment
which
used
conservative
assumptions
in
lieu
of
site­
specific
data.
The
results
demonstrated
negligible
risks
for
potential
chronic
cancer,
chronic
noncancer,
and
acute
noncancer
health
endpoints.
Also,
no
significant
human
health
multipathway
or
ecological
risks
were
identified.
Had
the
resulting
risks
been
determined
to
be
non­
negligible,
a
more
refined
analysis
with
sitespecific
data
would
have
been
necessary.
The
assessment
is
described
in
detail
in
the
memorandum
A
Residual
Risk
Assessment
for
the
Industrial
Process
Cooling
Source
Category,@
which
is
available
in
the
docket.

Since
our
assessment
shows
that
sources
subject
to
the
IPCT
NESHAP
pose
maximum
lifetime
excess
cancer
risks
which
are
significantly
less
than
1
in
1
million,
EPA
concluded
that
public
health
is
protected
with
an
ample
margin
of
13
safety,
and
since
noncancer
health
risks
and
ecological
risks
were
also
found
to
be
insignificant
for
this
source
category,
EPA
is
not
obligated
to
adopt
standards
under
section
112(
f)
of
the
CAA.

D.
What
were
the
conclusions
of
the
technology
review?

Section
112(
d)(
6)
of
the
CAA
requires
EPA
to
review,

and
revise
as
necessary
(
taking
into
account
developments
in
practices,
processes,
and
control
technologies),
emission
standards
promulgated
under
section
112
no
less
often
than
every
8
years.
As
we
stated
in
the
preamble
to
the
Coke
Ovens
residual
risk
rule
(
70
FR
20009,
April
15,
2005),
and
as
discussed
below,
the
facts
underlying
a
section
112(
f)

determination
should
be
key
factors
in
making
any
subsequent
section
112(
d)(
6)
determinations.
For
this
and
several
other
source
categories,
we
were
under
consent
decree
deadlines
to
complete
both
the
section
112(
d)(
6)
technology
review
and
the
section
112(
f)(
2)
residual
risk
analysis
by
the
same
date.
As
a
result,
we
conducted
the
two
reviews
concurrently
and
did
not
have
the
results
of
the
section
112(
f)(
2)
analysis
before
we
began
the
section
112(
d)(
6)

technology
review.

For
the
IPCT
source
category,
the
emission
standards
imposed
an
absolute
prohibition
on
the
use
of
chromium­
based
water
treatment
chemicals
in
IPCT.
As
the
emission
14
standards
imposed
for
this
particular
source
are
already
at
the
most
stringent
level,
no
more
stringent
standards
could
be
imposed.
Nor
has
EPA
received
any
evidence
which
would
justify
a
downward
revision
of
the
standards.
In
the
residual
risk
analysis
discussed
above,
EPA
has
considered
risks
for
HAP
emissions
that
are
not
currently
subject
to
emission
standards
but
are
attributable
to
the
source
category
or
subcategory.
Since
the
risk
from
other
HAP
emitted
from
IPCT
due
to
the
addition
of
water
treatment
chemicals
was
determined
to
be
very
low
and
the
emission
standards
already
preclude
the
use
of
chromium­
based
water
treatment
chemicals,
we
concluded
that
no
further
controls
are
necessary
under
112(
d)(
6).

E.
What
was
the
proposed
action?

On
October
24,
2005
(
70
FR
61411),
based
on
the
findings
from
our
residual
risk
and
technology
review,
we
proposed
no
further
action
to
revise
the
NESHAP
and
requested
public
comment.

II.
Today's
Action
A.
What
is
today's
final
action?

Today's
final
action
responds
to
public
comments
received
on
the
proposed
action
and
announces
our
final
decision
to
amend
the
applicability
section
of
the
rule.

B.
What
comments
were
received
on
the
proposed
action?
15
In
the
proposed
action,
we
requested
public
comment
on
our
residual
risk
review
and
our
technology
review
and
on
issues
of
delisting
the
source
category
and
conducting
future
technology
reviews.
By
the
end
of
the
public
comment
period,
comments
from
nine
entities
had
been
received.
A
summary
of
the
major
comments
and
EPA's
responses
are
provided
below
in
sections
II.
B.
1
through
II.
B.
7
of
this
preamble.

1.
Residual
Risk
Approach
Comment:
Two
commenters
urged
EPA
to
carefully
lay
out
the
context
and
framework
of
the
Residual
Risk
Program
to
ensure
that
the
public
understands
the
program
and
can
adequately
evaluate
EPA's
decisions
regarding
residual
risk.

The
commenters
identified
several
specific
aspects
of
the
program,
which
they
believe
need
to
be
conveyed
to
the
public.
Among
those,
they
included:
the
success
of
the
MACT
program
in
controlling
HAP
emissions;
further
regulatory
steps
are
not
required
if
EPA
determines
that
existing
MACT
standards
have
provided
an
ample
margin
of
safety;
and
the
public
can
be
assured
that
residual
risk
rules
will
provide
such
a
margin
of
safety
in
those
cases
where
the
standard
has
not
achieved
an
ample
margin
of
safety.
The
commenters
also
stated
that
it
is
important
for
EPA
to
put
the
risks
associated
with
major
stationary
16
sources
in
the
proper
context.
The
commenters
stated
that
major
stationary
sources
account
for
only
a
small
percentage
of
the
estimated
cancer
risk
from
HAP
nationwide.
In
addition,
they
urged
EPA
to
present
risk
from
air
toxics
in
context
with
the
risks
from
other
forms
of
air
pollution.

Specifically,
they
pointed
out
that
the
unit
risk
factors
assigned
to
air
toxics
are
much
more
conservative
than
the
factors
assigned
to
criteria
pollutants.
As
a
result,
risk
estimates
for
criteria
pollutants
should
not
be
compared
to
estimates
of
risk
based
on
HAP
emissions
from
stationary
sources
subject
to
NESHAP.

Response:
We
agree
that
it
is
important
to
provide
context
for
any
residual
risk
rule.
In
this
preamble,
we
describe
the
MACT
program
and
its
impact
on
the
IPCT
source
category.
We
also
describe
our
statutory
authority
and
our
obligations
to
assess
risks
to
human
health
and
the
environment
under
section
112(
f)
of
the
CAA,
as
well
as
the
requirement
to
further
regulate
categories
of
sources
if
any
of
the
estimated
individual
cancer
risks
exceed
the
statutory
trigger
level
of
1
in
1
million.

The
risks
posed
by
any
individual
major
stationary
source
depend
upon
a
number
of
factors,
including
emission
rates
at
the
source,
proximity
of
exposed
populations
to
the
emission
source,
the
specific
HAP
emitted,
local
17
meteorological
conditions,
and
terrain
conditions
surrounding
the
source.
Therefore,
the
relative
contribution
of
a
particular
major
stationary
source
to
individual
risk
levels
in
its
vicinity
will
vary
dramatically
depending
on
the
local
conditions
at
and
around
that
specific
source.
This
variability
is
not
captured
by
the
national
average
contribution
of
major
sources
to
population
risk
levels
mentioned
by
the
commenter,
whereas
the
risk
assessments
we
perform
for
the
purposes
of
evaluating
residual
risk
are
designed
specifically
to
capture
localized
individual
risks
associated
with
individual
sources.

We
agree
that
our
screening
risk
assessment
for
the
IPCT
source
category
appropriately
contains
a
number
of
health­
protective
assumptions
and
uses
health­
protective
inhalation
risk
values.
The
overall
result
is
a
screening
assessment
that
is
designed
to
overestimate,
rather
than
underestimate,
risks.
The
commenters
make
the
seemingly
contradictory
arguments
that
we
should
both
present
risks
from
air
toxics
in
the
context
of
those
from
criteria
pollutants
and
that
it
is
inappropriate
to
make
direct
comparisons
between
assessments
of
risk
for
air
toxics
and
criteria
pollutants.
Given
the
different
goals
of
the
residual
risk
program
and
the
criteria
pollutant
program,
we
18
agree
with
their
second
point
that
estimates
of
risk
generated
for
air
toxics
are
not
directly
comparable
to
those
generated
for
criteria
pollutants.

Comment:
Four
commenters
expressed
support
for
EPA's
tiered
approach
to
evaluating
residual
risk
by
first
performing
a
screening
assessment,
followed
by
a
refined
assessment.
One
commenter
commented
that,
if
a
screening
risk
assessment
based
on
conservative
assumptions
showed
that
risks
are
negligible,
no
further
assessments
or
actions
should
be
taken.
All
four
commenters
stated
that
EPA
must
proceed
with
the
refined
approach
unless,
as
was
the
case
for
IPCT,
the
worst­
case
screening
assessment
indicates
that
the
risk
is
less
than
1
in
1
million.
One
commenter
stated
that
in
evaluating
the
residual
risk
for
IPCT,
EPA
correctly
used
the
same
approach
used
for
the
1989
Benzene
NESHAP
(
40
CFR
part
61,
subpart
Y).

Response:
We
acknowledge
the
commenters'
support
of
our
general
approach
to
risk
assessment
and
agree
that,
had
risks
from
the
IPCT
exceeded
the
statutory
trigger
of
1
in
1
million
cancer
risk
or
exceeded
a
similar
level
of
protection
for
threshold
effects,
we
would
have
conducted
a
more
refined
assessment.

Comment:
Three
commenters
stated
that,
when
presenting
the
results
of
the
initial
screening
assessment,
it
is
19
important
for
EPA
to
explain
the
conservative
nature
of
the
assumptions
and
the
limitations
of
this
approach
to
avoid
any
misperceptions
by
the
public.
Two
of
the
commenters
added
that
otherwise,
the
public
may
mistakenly
believe
that
the
contribution
to
risk
from
major
stationary
sources
is
much
greater.
The
commenters
also
encouraged
EPA
to
use
the
most
accurate
emission
data
and
models
to
ensure
accurate
risk
assessments
and
to
avoid
mischaracterizing
the
risk
from
the
regulated
sources.
One
commenter
added
that
sitespecific
data
should
be
used
in
residual
risk
assessments
when
possible.

Response:
We
agree
that
our
risk
assessment
for
IPCT
contains
a
number
of
health­
protective
assumptions
resulting
in
a
screening
assessment
that
is
designed
to
overestimate,

rather
than
underestimate,
risks.
However,
the
healthprotective
assumptions
incorporated
into
this
screening
risk
assessment
are
appropriate
because
we
are
generalizing
the
results
from
a
single
model
facility
to
all
cooling
towers
in
the
source
category.
We
designed
this
approach
to
ensure
that
the
model
facility
presents
at
least
as
much
risk
as
the
worst­
case
actual
facility.
Then,
by
demonstrating
that
risks
from
our
worst­
case
model
facility
are
low,
we
can
easily
conclude
that
risks
from
IPCT
at
any
actual
facility
will
also
be
low.
20
The
details
of
our
risk
assessment
can
be
found
in
the
memorandum
titled,
"
Residual
Risk
Assessment
for
the
Industrial
Process
Cooling
Towers
Source
Category,"
which
is
available
in
the
docket.
As
indicated
above,
a
number
of
health­
protective
assumptions
are
incorporated
into
the
assessment.
For
example,
we
based
the
configuration
of
our
model
facility
on
one
of
the
largest
and
highest­
emitting
actual
facilities
in
the
IPCT
source
category.
We
estimated
worst­
case
emission
rates
for
this
facility
by
assuming
that
it
emitted
methanol,
ethylene
thiourea,
and
chloroform
from
its
cooling
towers
even
though
it
is
unlikely
that
any
actual
towers
would
emit
more
than
one
of
these
HAP.
We
assumed
that
individuals
are
exposed
to
IPCT
emissions
for
24
hours
per
day
and
365
days
per
year
for
70
years
although
the
activity
patterns
of
actual
individuals
would
decrease
exposure.
Finally,
we
assumed
that
people
lived
at
locations
very
close
to
the
cooling
towers.
Often,
these
locations
would
actually
be
within
the
facility's
fenceline,

where
no
one
actually
resides.
This
combination
of
healthprotective
assumptions
is
appropriate
for
the
IPCT
assessment
because
it
allows
us
to
generalize
the
low­
risk
finding
from
a
single
model
source
to
all
sources
in
the
category.
If
we
had
not
been
able
to
use
this
approach
to
make
the
low­
risk
finding,
we
would
indeed
have
collected
21
more
refined,
site­
specific
data
to
develop
a
more
precise
risk
assessment,
but,
in
this
situation,
that
step
was
not
necessary.

2.
Co­
Located
Sources
Comment:
Four
commenters
agreed
with
EPA's
approach
of
considering
the
risk
associated
with
the
specific
sources
regulated
by
the
NESHAP
and
not
considering
co­
located
sources.
Two
of
the
commenters
noted
that
the
risk
attributed
to
co­
located
sources
will
be
evaluated
when
the
appropriate
source
category
is
reviewed
under
section
112(
f)

of
the
CAA.
The
commenters
stated
that
section
112(
f)

clearly
indicates
that
Congress
intended
the
residual
risk
assessment
for
a
specific
source
category
to
focus
on
the
source
category,
as
defined
in
the
rulemaking
under
section
112(
d),
and
not
to
encompass
other
source
categories.

Response:
We
agree
with
commenters
that
the
risks
attributable
to
sources
collocated
with
IPCT
will
be
evaluated
when
the
appropriate
category
is
reviewed
under
section
112(
f).
We
do
not
agree
that
our
section
112(
f)

residual
risk
analyses
must
always
focus
only
on
the
source
category
as
defined
in
the
rulemaking
under
section
112(
d)

or
that
Congress
intended
to
limit
all
residual
risk
analyses
to
the
individual
source
categories
in
question.

As
we
stated
in
the
preamble
to
the
Coke
Ovens
residual
risk
22
rule
(
70
FR
19998,
April
15,
2005),
"
EPA
disagrees
that
section
112(
f)
precludes
EPA
from
considering
emissions
other
than
those
from
the
source
category
or
subcategory
entirely."
Rather,
we
have
concluded
that,
when
the
statutory
risk
trigger
is
exceeded,
the
two­
step
approach
set
forth
in
the
preamble
to
the
Benzene
NESHAP
(
54
FR
38044,
September
14,
1989)
remains
the
approach
that
we
should
follow
in
determinations
under
section
112(
f).
At
the
first
step,
when
determining
"
acceptable
risk,"
we
will
consider
risks
that
result
from
emissions
from
the
source
category
only.
However,
during
the
second
step,
we
must
determine
whether
additional
reductions
should
be
required
to
protect
public
health
with
"
an
ample
margin
of
safety."

EPA
believes
that
one
of
the
"
other
relevant
factors"
that
may
be
considered
in
this
second
step
is
co­
location
of
other
emission
sources
that
augment
the
identified
risks
from
the
source
category.
In
the
case
of
coke
ovens,
this
included
the
consideration
of
co­
located
source
categories
that
are
integral
parts
of
the
same
industrial
activity.

Additional
information
regarding
co­
located
sources
and
112(
f)
requirements
is
provided
in
the
preamble
to
the
coke
oven
residual
risk
rule
(
70
FR
19996).

3.
Approach
When
No
Pre­
existing
NESHAP
Level
of
Control
Exists
23
Comment:
Three
commenters
responded
to
our
request
for
comment
on
the
approach
to
evaluating
residual
risk
when
no
pre­
existing
NESHAP
requirement
exists
for
the
HAP
emissions.
For
example,
in
the
case
of
IPCT,
the
residual
risk
assessment
considered
three
HAP
that
were
not
regulated
under
the
NESHAP.
The
commenters
agreed
with
EPA's
approach,
stating
that
it
is
appropriate
to
evaluate
and
control
emissions
of
other
HAP
if
those
HAP
pose
an
unacceptable
level
of
risk.

Response:
We
acknowledge
the
commenters'
support
of
our
approach
to
evaluating
residual
risk
by
considering
all
HAP
emitted
by
the
regulated
source
category.
Section
112(
f)
requires
EPA
to
determine
if
an
ample
margin
of
safety
has
been
provided
for
the
source
category
and
as
part
of
that
determination
we
identified
other
HAP
that
are
emitted
from
the
source
category.

4.
Subcategorizing
Source
Categories
to
Satisfy
CAA
Section
112(
f)(
2)

Comment:
Five
commenters
responded
to
our
request
for
comment
on
the
possibility
of
subcategorizing
source
categories
for
the
purpose
of
satisfying
the
residual
risk
requirements
specified
in
section
112(
f)(
2)
of
the
CAA.
All
five
commenters
supported
the
concept
of
subcategorizing
source
categories
characterized
by
a
broad
range
of
risk
24
levels.
Four
of
the
commenters
noted
that
section
112(
c)

gives
EPA
broad
discretion
in
creating
and
modifying
categories
and
subcategories
of
sources.
By
subcategorizing,
EPA
can
distinguish
between
lower
risk
subcategories
and
those
categories
for
which
additional
control
is
warranted.
One
of
the
commenters
pointed
out
that
emission
characteristics,
which
vary
by
subcategory,

define
the
risk
of
adverse
health
and
environmental
impacts.

Therefore,
establishing
separate
subcategories
on
the
basis
of
risk
would
be
consistent
with,
and
would
best
achieve,

the
overall
statutory
mandate
of
section
112
of
the
CAA.

The
same
commenter
stated
that
Congress
provided
a
mechanism
and
criteria
for
subcategorizing
with
respect
to
risk
in
sections
112(
c)(
9)(
B)(
i)
and
(
ii)
to
preclude
overregulating
sources
that
can
meet
consistent
low­
risk
criteria.
Four
of
the
commenters
believed
that
subcategorizing
with
respect
to
residual
risk
would
encourage
sources
to
develop
sitespecific
approaches
for
reducing
risk
in
order
to
avoid
additional
regulatory
control,
work
practices,
and
associated
permitting
costs.
One
commenter
stated
that
the
intent
of
Congress
was
that
EPA
should
focus
MACT
standards
and
residual
risk
requirements
on
those
sources
that
present
a
risk
of
concern.
Two
of
the
commenters
cited
the
"
Residual
Risk
Report
to
Congress"
(
EPA­
453/
R­
99­
001),
which
25
supports
the
concept
of
regulating
only
those
sources
within
a
source
category
associated
with
unacceptable
risk.
Three
of
the
commenters
commented
that
sources
within
a
lower
risk
subcategory
would
still
be
subject
to
the
NESHAP
and
would
have
to
continue
complying
with
the
standard
in
order
to
maintain
its
low­
risk
status.
The
commenters
further
explained
that,
even
if
EPA
decides
not
to
subcategorize
based
on
risk,
residual
risk
standards
should
focus
only
on
the
subset
of
sources
that
poses
unacceptable
risk.

Response:
We
acknowledge
the
commenters'
support
for
subcategorizing
based
on
risk
in
order
to
satisfy
section
112(
f)(
2)
of
the
CAA.
For
the
IPCT
source
category,
our
risk
assessment
indicated
that
all
sources
in
the
category
are
low­
risk.
Therefore,
there
is
no
need,
in
the
present
case,
to
subcategorize
based
on
risk
or
any
other
criteria.

5.
Emissions
from
IPCT
Comment:
One
commenter
commented
on
our
conclusion
that
emissions
of
chlorine
from
IPCT
are
unlikely
under
normal
operating
conditions.
We
based
this
conclusion
on
discussions
with
water
treatment
chemical
suppliers
and
information
presented
in
several
technical
publications
on
water
treatment,
all
of
which
clearly
stated
that
chlorine
emissions
occur
only
under
acidic
conditions
(
i.
e.,
pH
of
3.0
or
less),
and
IPCT
water
treatment
programs
are
designed
26
to
maintain
alkaline
conditions
(
i.
e.,
pH
of
7.5
to
9.0)
in
the
cooling
water.
The
commenter
stated
that
IPCT
that
are
treated
with
chlorine
gas
(
Cl2)
experience
significant
flash­
off
of
molecular
chlorine.
He
noted
that
one
facility
estimated
that
chlorine
emissions
from
flash­
off
amounted
to
18
percent
of
the
chlorine
gas
used
to
treat
the
cooling
water
in
an
IPCT,
and
that
annual
emissions
of
chlorine
from
the
IPCT
were
estimated
to
be
18.2
tons.
The
commenter
did
not
provide
documentation
for
that
estimate.
However,
he
did
cite
a
report
prepared
by
the
University
of
Texas
for
the
Texas
Natural
Resource
Conservation
Commission
(
TNRCC),

"
Emission
Inventory
for
Atomic
Chlorine
Precursors
in
Southeast
Texas,"
which
supports
his
comments
regarding
chlorine
emissions
due
to
flash­
off
from
IPCT.
The
TNRCC
Report
also
states
that
the
greater
the
pH,
the
greater
the
flash­
off
rate,
which
may
appear
to
contradict
our
conclusion
regarding
the
relationship
between
pH
and
Cl2
emissions
from
IPCT.

Response:
As
noted
above,
the
commenter
did
not
provide
documentation
for
the
estimate
of
18.2
tpy
of
chlorine
emissions
from
a
single
IPCT.
We
assume
that
the
basis
for
that
estimate
was
the
TNRCC
Report.
We
reviewed
the
TNRCC
Report,
as
well
as
the
primary
references
used
as
the
basis
for
the
chlorine
emission
estimates
presented
in
27
the
report.
Based
on
our
review,
we
maintain
our
conclusion
that
emissions
of
Cl2
from
IPCT
are
not
likely
to
occur
under
normal
operating
conditions.

With
respect
to
the
discrepancy
between
our
conclusions
regarding
emissions
of
chlorine
from
IPCT,
the
statement
by
the
commenter,
and
the
information
presented
in
the
TNRC
Report,
there
are
two
issues
that
must
be
resolved:
(
1)

which
chlorine
species
are
emitted
from
IPCT,
and
(
2)
what
is
the
relationship
between
those
emissions
and
the
pH
of
the
cooling
water.

When
gaseous
chlorine
is
added
to
cooling
water,
it
dissociates
to
form
hypochlorous
acid
(
HClO),
hydrogen
(
H+),

and
chloride
(
Cl­)
ions.
The
HClO
further
dissociates
to
form
hypochlorite
(
ClO­)
and
H+
ions.
With
respect
to
the
chlorine
species
emitted,
the
TNRCC
Report
presents
estimates
assuming
that
chlorine
emissions
are
entirely
in
the
form
of
Cl2.
The
Report
does
not
provide
the
basis
for
this
assumption,
but
does
note
that
".
.
.
chlorine
may
be
released
as
HClO,
Cl2,
or
in
other
chemical
forms
.
.
."

The
Report
later
states
that
emissions
".
.
.
may
be
in
the
form
of
HOCl
rather
than
Cl2."
Apparently,
because
the
focus
of
the
TNRCC
Report
was
the
magnitude
of
the
emissions
rather
than
the
form
of
the
chlorine
emitted,
the
researchers
did
not
attempt
to
determine
which
chlorine
28
species
would
be
emitted.
The
primary
references
cited
in
the
TNRCC
Report
regarding
chlorine
emissions
from
IPCT
are
two
journal
articles
from
1984
by
Holzwarth,
et.
al.
The
introduction
to
the
first
of
those
articles
explains
that
chlorine
gas
added
to
cooling
water
".
.
.
immediately
reacts
with
water
to
form
HOCl
and
HCl."
All
of
the
subsequent
discussion
and
calculations
in
both
papers
regarding
flash­
off
are
in
terms
of
HOCl
and
other
non­
Cl2
chlorine
compounds.
In
fact,
Cl2
is
not
mentioned
again
in
either
article.
In
other
words,
the
Holzwarth
articles
support
our
conclusion
that
chlorine
is
not
emitted
from
IPCT
in
the
form
of
Cl2.

With
respect
to
the
relationship
between
pH
and
emissions
of
chlorine
species,
we
do
not
argue
that
emissions
from
flash­
off
may
increase
with
increasing
pH.

However,
our
assessment
concluded
that
these
emissions
would
be
entirely
in
the
form
of
HOCl
and
not
as
Cl2.
The
studies
by
Holzwarth,
et.
al.
also
support
this
conclusion,
that
emissions
of
HOCl
increase
with
increasing
pH,
while
emissions
of
Cl2
decrease
with
increasing
pH.

In
summary,
we
believe
our
conclusions
regarding
emissions
of
Cl2
from
IPCT
are
correct.
Neither
the
commenter,
nor
the
references
cited
by
the
commenter
provide
any
basis
for
concluding
otherwise.
29
6.
Delisting
the
IPCT
Source
Category
Comment:
Six
commenters
responded
to
our
request
for
comment
on
the
issue
of
delisting
the
IPCT
source
category
in
light
of
the
results
of
the
residual
risk
assessment.

Two
of
the
commenters
opposed
delisting
the
source
category;

one
of
the
commenters
supported
delisting;
and
the
other
commenters,
although
not
opposed
to
delisting,
found
no
compelling
reason
to
do
so.
One
of
the
commenters
who
opposed
delisting
stated
that
delisting
the
source
category
would
not
be
appropriate
because
such
action
would
allow
owners
and
operators
of
IPCT
to
revert
back
to
using
chromium
water
treatment
chemicals.
The
commenter
also
noted
that
delisting
the
source
category
would
require
State
and
local
agencies
to
amend
their
rules
accordingly.

Because
there
would
not
be
a
NESHAP
to
adopt
by
reference,

State
and
local
agencies
would
be
required
to
develop
and
adopt
their
own
regulations
on
IPCT.
In
addition,
the
commenter
pointed
out
that
some
regulatory
agencies
are
prevented
from
adopting
rules
that
are
more
stringent
than
Federal
requirements.
In
those
cases,
States
and
local
agencies
would
have
no
legal
means
of
preventing
IPCT
owners
and
operators
from
resuming
the
use
of
chromium
water
treatment
chemicals
in
IPCT.

The
other
commenter
who
opposed
delisting
stated
that,
30
if
the
source
category
were
delisted,
there
would
be
nothing
to
prevent
sources
from
increasing
their
HAP
emissions
substantially
or
changing
their
processes
to
emit
new
HAP,

either
of
which
could
result
in
HAP
levels
that
are
unacceptable
to
public
health
and
the
environment.
He
noted
that
such
action
would
disregard
the
possibility
that
HAP
emissions
have
been
reduced
to
an
acceptable
level
because
of
the
NESHAP.

Three
of
the
commenters
were
not
opposed
to
delisting
the
IPCT
source
category,
but
remarked
that
there
was
no
compelling
reason
to
do
so.
The
commenters
noted
that,
even
though
the
IPCT
NESHAP
does
not
apply
to
any
existing
sources,
it
is
possible
for
the
rule
to
apply
to
sources
in
the
future.
The
commenters
gave
the
example
of
an
area
source,
which
operated
an
IPCT
using
chromium
water
treatment
chemicals
and
later
became
a
major
source.
Once
the
facility
became
a
major
source,
it
would
be
subject
to
the
NESHAP
and
would
have
to
discontinue
the
use
of
chromium
water
treatment
chemicals.
The
commenters
stated
that,
on
the
other
hand,
delisting
a
source
category
does
not
affect
the
applicability
of
an
existing
NESHAP.
The
commenters
explained
that
the
applicability
of
the
Asbestos
NESHAP
(
40
CFR
part
61,
subpart
M)
was
unchanged
after
the
source
category
was
delisted.
Finally,
the
commenters
pointed
out
31
that
none
of
the
applicability
requirements
of
40
CFR
part
63
standards
(
i.
e.,
NESHAP)
depend
on
source
category
listing.

One
of
the
commenters
supported
delisting
the
IPCT
source
category.
The
commenter
stated
that
our
request
for
comment
on
this
issue
implied
that
we
interpreted
section
112(
c)(
9)
of
the
CAA
to
apply
only
before
a
MACT
standard
has
been
promulgated.
According
to
the
commenter,
section
112(
c)(
9)
grants
EPA
the
authority
to
delist
a
source
category
whenever
the
Administrator
determines
that
the
risks
meet
the
established
criteria.
The
commenter
noted
that
delisting
source
categories
based
on
risk
prior
to
establishing
standards
under
section
112(
d)
actually
would
conflict
with
the
sequence
of
EPA's
duties
under
section
112,
which
requires
EPA
to
evaluate
residual
risk
8
years
after
promulgation.
In
addition,
the
commenter
pointed
out
that
EPA
would
likely
not
have
sufficient
data
to
fully
assess
the
risk
until
several
years
after
a
standard
had
been
in
place.
Finally,
if
EPA
were
to
delist
the
source
category,
section
112(
c)(
9)
could
still
be
used
to
establish
requirements
to
ensure
that
the
risk
remains
within
acceptable
levels
if
EPA
were
to
conclude
that
the
risk
associated
with
the
source
category
could
become
unacceptable
in
the
future.
32
Response:
Based
on
our
risk
assessment
of
the
IPCT
source
category,
we
have
concluded
that
these
sources
are
low­
risk
and,
therefore,
that
no
further
standards
are
required
to
protect
public
health
with
an
ample
margin
of
safety
or
to
protect
the
environment.
However,
we
agree
with
the
commenter
who
argues
that
this
conclusion
is
based,

at
least
in
part,
on
the
fact
that
the
MACT
requirements
for
these
sources
prevent
IPCT
from
using
chromium­
based
water
treatment
strategies.
Further,
we
disagree
with
the
comment
that
delisting
would
not
affect
the
existing
NESHAP.
The
commenter
cited
the
delisting
action
following
the
Asbestos
NESHAP
as
support
for
their
argument,
noting
that
the
applicability
of
that
rule
was
not
affected
by
delisting.

However,
the
Asbestos
NESHAP
was
established
under
40
CFR
part
61,
which
is
not
directly
relevant
in
this
situation
since
the
IPCT
NESHAP
is
a
40
CFR
part
63
rule.
If
we
delist
this
source
category,
it
is
our
opinion
that
existing
facilities
with
IPCT
would
no
longer
be
subject
to
the
NESHAP
and
would
not
be
banned
from
using
chromium.
If
any
sources
reverted
to
using
chromium,
risks
could
increase,

and
the
basis
for
our
finding
that
the
source
category
is
low­
risk
would
be
compromised.
Thus,
since
compliance
with
the
MACT
standard
is
part
of
the
basis
for
our
low­
risk
determination,
we
believe
our
policy
objectives
are
best
33
served
if
we
do
not
delist
the
IPCT
source
category.

However,
as
long
as
the
NESHAP
exists
and
prohibits
the
use
of
chromium­
based
water
treatment
chemicals,
we
agree
with
the
commenters
who
suggest
that
IPCT
sources
no
longer
using
these
chemicals
should
not
be
subject
to
this
NESHAP.

Therefore,
we
are
amending
the
applicability
section
of
the
rule
to
clarify
that
sources
no
longer
using
chromium­
based
water
treatment
chemicals
are
not
subject
to
this
NESHAP.

The
NESHAP
remains
in
effect,
and
any
source
that
uses
chromium­
based
water
treatment
chemicals
will
be
subject
to
the
rule
and
in
violation.

Contrary
to
one
commenter's
contention,
we
do
not
interpret
section
112(
c)(
9)
of
the
CAA
to
apply
only
before
a
MACT
standard
has
been
promulgated,
although
that
is
expected
to
be
the
situation
in
which
it
is
most
likely
exercised.
We
agree
that
section
112(
c)(
9)
grants
EPA
the
authority
to
delist
a
source
category
when
the
Administrator
determines
that
risks
meet
the
established
criteria,

including
after
promulgation
of
a
MACT
standard.

The
Agency
would
like
to
remove
the
burden
of
the
repetitive
review
of
Section
112
standards
for
low
risk
source
categories.
At
the
same
time,
we
think
it
is
appropriate
to
maintain
the
MACT
controls
in
this
case.
We
plan
to
further
investigate
approaches
for
removing
low­
risk
34
source
categories
from
the
Section
112
universe
while
maintaining
MACT­
level
controls.
An
example
of
a
similar
approach
is
found
in
the
Plywood
and
Composite
Wood
Products
MACT
where
we
allow
a
subcategory
of
facilities
to
reduce
emissions
to
acceptable
risk
levels
through
Title
5
permits
and
remove
them
from
the
MACT
universe.

7.
Technology
Reviews
Under
CAA
Section
112(
d)(
6)

Comment:
One
commenter
remarked
that
EPA
should
not
have
conducted
an
initial
technology
review
of
the
IPCT
source
category.
The
commenter
explained
that
once
a
residual
risk
determination
indicates
the
risk
is
acceptable,
EPA
must
find
that
revising
the
standard
under
CAA
section
112(
d)(
6)
is
not
necessary.
The
commenter
stated
that
the
legislative
history
of
the
CAA
demonstrates
that
Congress
rejected
imposing
controls
beyond
levels
considered
to
be
safe
and
protective
of
public
health
because
those
controls
would
impose
regulatory
costs
without
any
public
health
benefit.
The
commenter
stated
that,
if
Congress
had
intended
EPA
to
conduct
technology
reviews
regardless
of
the
outcome
of
the
residual
risk
assessment,

there
would
be
no
need
for
CAA
section
112(
f).
The
commenter
believes
that
technology
reviews
under
section
112(
d)(
6)
were
meant
to
be
regulatory
backstop
authority
for
residual
risk
reviews,
similar
to
the
MACT
hammer
provision
35
in
section
112(
j)
of
the
CAA.
That
is,
if
EPA
failed
to
address
the
residual
risk
for
a
source
category,
section
112(
d)(
6)
authority
could
be
used
to
ensure
that
advances
in
technology
could
still
be
applied
to
the
source
category.

Response:
We
disagree
with
the
comment
that
we
should
not
have
conducted
an
initial
technology
review
under
CAA
section
112(
d)(
6)
for
the
IPCT
source
category.
The
timing
requirements
for
the
initial
analysis
under
section
112(
d)(
6)
coincide
with
those
for
the
residual
risk
analysis.
Thus,
it
is
appropriate
for
us
to
conduct
both
analyses
at
the
same
time.
Although
the
results
of
the
risk
analysis
may
impact
future
section
112(
d)(
6)
technology
reviews,
these
results
do
not
negate
the
need
to
perform
the
initial
review.
Additional
information
regarding
the
relationship
between
residual
risk
standards
and
112(
d)(
6)

review
requirements
is
provided
in
the
preamble
to
the
Coke
Oven
residual
risk
rule
(
70
FR
20008,
April
15,
2005).

Comment:
Seven
commenters
responded
to
our
request
for
comment
on
continuing
technology
reviews
every
8
years
for
source
categories
subject
to
NESHAP,
as
required
by
section
112(
d)(
6)
of
the
CAA.
Four
commenters
stated
that
EPA
should
not
use
a
"
bright
line
approach"
in
determining
the
need
for
technology
reviews
under
section
112(
d)(
6)
of
the
CAA.
For
example,
the
decision
of
whether
or
not
to
perform
36
a
technology
review
should
not
be
based
on
a
1­
in­
1­
million
risk
level,
as
is
the
case
for
residual
risk.
One
of
those
commenters
stated
that
discontinuing
technology
reviews
would
be
contrary
to
the
requirements
of
the
CAA.
The
commenter
noted
that
the
phrase
".
.
.
every
8
years"

implies
a
continuum
rather
than
a
single
action,
and
if
Congress
had
intended
the
technology
review
to
be
a
one­
time
requirement,
it
would
have
used
other
language
in
the
CAA.

As
an
example
of
a
one­
time
requirement,
the
commenter
cited
CAA
section
112(
n)(
1),
which
states
that
"
The
Administrator
shall
conduct,
and
transmit
to
Congress
not
later
than
4
years
after
the
date
of
enactment
.
.
."
The
other
commenter
who
opposed
discontinuing
technology
reviews
remarked
that,
without
future
reviews,
it
is
unlikely
that
EPA
would
know
what
new
technologies
have
been
developed
or
know
of
any
unforeseeable
circumstances
that
might
substantially
change
the
source
category
or
its
emissions.

Three
of
the
commenters
stated
that,
by
implementing
residual
risk
requirements
under
section
112(
f)
or
determining
that
residual
risk
requirements
are
not
warranted,
EPA
completes
its
obligation
to
conduct
technology
reviews
under
section
112(
d)(
6)
of
the
CAA.

Thus,
once
the
residual
risk
has
been
evaluated
and
the
appropriate
action
taken,
technology
reviews
are
no
longer
37
required.
However,
the
commenters
also
stated
that
later
technology
reviews
may
be
appropriate
if
the
ample
margin
of
safety
established
by
the
residual
risk
process
is
based
largely
on
cost
or
technical
feasibility,
and
feasible,

cost­
effective
controls
are
identified
in
the
future.
Four
of
the
commenters
stated
that
technology
reviews
under
section
112(
d)(
6)
should
not
provide
for
a
continuing
technology
ratchet
based
on
the
availability
of
new
technology.
Instead,
technology
reviews
should
be
conducted
in
the
context
of
providing
an
ample
margin
of
safety
under
section
112(
f)
of
the
CAA.

Response:
We
agree
that
a
technology
review
is
required
every
8
years
for
emission
standards
under
112(
d)

or
if
new
standards
are
issued
pursuant
to
112(
f).
However,

if
the
ample
margin
of
safety
analysis
for
a
section
112(
f)

standard
shows
that
remaining
risk
for
non­
threshold
pollutants
falls
below
1
in
1
million
and
for
threshold
pollutants
falls
below
a
similar
threshold
of
safety,
then
further
revision
would
not
be
needed
because
an
ample
margin
of
safety
has
already
been
assured.
Additional
information
regarding
the
relationship
between
residual
risk
standards
and
112(
d)(
6)
review
requirements
is
provided
in
the
preamble
to
the
Coke
Oven
residual
risk
rule
(
70
FR
20008,

April
15,
2005).
38
Comment:
Four
commenters
commented
that
technology
reviews
under
section
112(
d)(
6)
should
be
limited
to
emission
standards
already
established
under
section
112(
d).

Three
of
the
commenters
stated
that,
although
it
is
appropriate
to
evaluate
and
control
emissions
of
other
HAP
not
regulated
by
the
NESHAP
under
section
112(
f),
such
HAP
should
not
be
considered
under
the
section
112(
d)(
6)

technology
review.

Response:
The
emission
standards
imposed
a
prohibition
on
the
use
of
chromium­
based
water
treatment
chemicals
in
IPCT.
Since
the
risk
from
other
HAP
emitted
from
IPCT
due
to
the
addition
of
water
treatment
chemicals
was
determined
to
be
very
low
and
the
emission
standards
already
preclude
the
use
of
chromium­
based
water
treatment
chemicals,
we
concluded
that
no
further
controls
are
necessary
under
either
112(
f)
or
112(
d)(
6).
As
stated
previously,
section
112(
d)(
6)
requires
that
the
emission
standard
be
reviewed
and
revised
as
necessary
no
less
often
than
every
8
years.

Additional
information
regarding
the
relationship
between
residual
risk
standards
and
112(
d)(
6)
review
requirements
is
provided
in
the
preamble
to
the
residual
risk
for
coke
ovens
(
70
FR
20008,
April
15,
2005).

III.
Statutory
and
Executive
Order
Reviews
A.
Executive
Order
12866:
Regulatory
Planning
and
Review
39
Under
Executive
Order
12866
(
58
FR
51735,
October
4,

1993),
EPA
must
determine
whether
a
regulatory
action
is
"
significant"
and,
therefore,
subject
to
Office
of
Management
and
Budget
(
OMB)
review
and
the
requirements
of
the
Executive
Order.
The
Executive
Order
defines
A
significant
regulatory
action
@

as
one
that
is
likely
to
result
in
a
rule
that
may:

(
1)
Have
an
annual
effect
on
the
economy
of
$
100
million
or
more,
or
adversely
affect
in
a
material
way
the
economy,
a
sector
of
the
economy,
productivity,
competition,

jobs,
the
environment,
public
health
or
safety,
or
State,

local,
or
tribal
governments
or
communities;

(
2)
Create
a
serious
inconsistency
or
otherwise
interfere
with
an
action
taken
or
planned
by
another
agency;

(
3)
Materially
alter
the
budgetary
impact
of
entitlements,
grants,
user
fees,
or
loan
programs,
or
the
rights
and
obligations
of
recipients
thereof;
or
(
4)
Raise
novel
legal
or
policy
issues
arising
out
of
legal
mandates,
the
President's
priorities,
or
the
principles
set
forth
in
the
Executive
Order.

Pursuant
to
the
terms
of
Executive
Order
12866,
OMB
has
notified
EPA
that
it
considers
this
a
A
significant
regulatory
action
@

within
the
meaning
of
the
Executive
Order.
EPA
has
submitted
this
action
to
OMB
for
review.
40
Changes
made
in
response
to
OMB
suggestions
or
recommendations
will
be
documented
in
the
public
record.

B.
Paperwork
Reduction
Act
The
final
rule
amendment
does
not
impose
any
information
collection
burden.
It
will
not
change
the
burden
estimates
from
those
previously
developed
and
approved
for
the
existing
NESHAP.
OMB
has
previously
approved
the
information
collection
requirements
contained
in
the
existing
regulation
(
40
CFR
part
63,
subpart
Q)

under
the
provisions
of
the
Paperwork
Reduction
Act,
44
U.
S.
C.
3501,
et
seq.
(
OMB
control
number
2060­
0268).

However,
this
information
collection
request
has
been
discontinued
because
the
information
requested
in
the
original
regulation
is
no
longer
needed.
41
Burden
means
the
total
time,
effort,
or
financial
resources
expended
by
persons
to
generate,
maintain,
retain,

or
disclose
or
provide
information
to
or
for
a
Federal
agency.
This
includes
the
time
needed
to
review
instructions;
develop,
acquire,
install,
and
utilize
technology
and
systems
for
the
purposes
of
collecting,

validating,
and
verifying
information,
processing
and
maintaining
information,
and
disclosing
and
providing
information;
adjust
the
existing
ways
to
comply
with
any
previously
applicable
instructions
and
requirements;
train
personnel
to
be
able
to
respond
to
a
collection
of
information;
search
data
sources;
complete
and
review
the
collection
of
information;
and
transmit
or
otherwise
disclose
the
information.

An
agency
may
not
conduct
or
sponsor,
and
a
person
is
not
required
to
respond
to
a
collection
of
information
unless
it
displays
a
currently
valid
OMB
control
number.

The
OMB
control
numbers
for
EPA
=

s
regulations
in
40
CFR
part
63
are
listed
in
40
CFR
part
9.

C.
Regulatory
Flexibility
Act
EPA
has
determined
that
it
is
not
necessary
to
prepare
a
regulatory
flexibility
analysis
in
connection
with
this
final
rule
amendment.

For
purposes
of
assessing
the
impacts
of
today
=

s
final
42
rule
amendment
on
small
entities,
small
entity
is
defined
as:
(
1)
a
small
business
as
defined
by
the
Small
Business
Administration
at
13
CFR
121.201;
(
2)
a
small
governmental
jurisdiction
that
is
a
government
of
a
city,
county,
town,

school
district,
or
special
district
with
a
population
of
less
than
50,000;
and
(
3)
a
small
organization
that
is
any
not­
for­
profit
enterprise
which
is
independently
owned
and
operated
and
is
not
dominant
in
its
field.

After
considering
the
economic
impacts
of
today
=

s
final
rule
amendment
on
small
entities,
EPA
has
concluded
that
this
final
action
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
The
final
rule
amendment
does
not
impose
any
requirements
on
small
entities.

D.
Unfunded
Mandates
Reform
Act
Title
II
of
the
Unfunded
Mandates
Reform
Act
of
1995
(
UMRA),
Public
Law
104­
4,
establishes
requirements
for
Federal
agencies
to
assess
the
effects
of
their
regulatory
actions
on
State,
local,
and
tribal
governments
and
the
private
sector.
Under
section
202
of
the
UMRA,
EPA
generally
must
prepare
a
written
statement,
including
a
cost­
benefit
analysis,
for
proposed
and
final
rules
with
A
Federal
mandates
@

that
may
result
in
expenditures
to
State,

local,
and
tribal
governments,
in
the
aggregate,
or
to
the
43
private
sector,
of
$
100
million
or
more
in
any
1
year.

Before
promulgating
an
EPA
rule
for
which
a
written
statement
is
needed,
section
205
of
the
UMRA
generally
requires
EPA
to
identify
and
consider
a
reasonable
number
of
regulatory
alternatives
and
adopt
the
least
costly,
most
cost­
effective,
or
least
burdensome
alternative
that
achieves
the
objectives
of
the
rule.
The
provisions
of
section
205
do
not
apply
when
they
are
inconsistent
with
applicable
law.
Moreover,
section
205
allows
EPA
to
adopt
an
alternative
other
than
the
least
costly,
most
cost­
effective,
or
least
burdensome
alternative
if
the
Administrator
publishes
with
the
final
rule
an
explanation
why
that
alternative
was
not
adopted.
Before
EPA
establishes
any
regulatory
requirements
that
may
significantly
or
uniquely
affect
small
governments,

including
tribal
governments,
it
must
have
developed
under
section
203
of
the
UMRA
a
small
government
agency
plan.
The
plan
must
provide
for
notifying
potentially
affected
small
governments,
enabling
officials
of
affected
small
governments
to
have
meaningful
and
timely
input
in
the
development
of
EPA
regulatory
proposals
with
significant
Federal
intergovernmental
mandates,
and
informing,

educating,
and
advising
small
governments
on
compliance
with
the
regulatory
requirements.
44
The
EPA
has
determined
that
the
final
rule
amendment
does
not
contain
a
Federal
mandate
(
under
the
regulatory
provisions
of
Title
II
of
the
UMRA)
for
State,
local,
or
tribal
governments
or
the
private
sector
because
it
imposes
no
enforceable
duty
on
any
State,
local,
or
tribal
governments
or
the
private
sector.
Thus,
today
=

s
final
amendment
is
not
subject
to
the
requirements
of
sections
202
and
205
of
the
UMRA.
In
addition,
EPA
has
determined
that
the
final
amendment
contains
no
regulatory
requirements
that
might
significantly
or
uniquely
affect
small
governments,

because
it
contains
no
requirements
that
apply
to
such
governments
or
impose
obligations
upon
them.

E.
Executive
Order
13132:
Federalism
Executive
Order
13132,
entitled
A
Federalism
@

(
64
FR
43255,
August
10,
1999),
requires
EPA
to
develop
an
accountable
process
to
ensure
A
meaningful
and
timely
input
by
State
and
local
officials
in
the
development
of
regulatory
policies
that
have
federalism
implications.@

A
Policies
that
have
federalism
implications
@

is
defined
in
the
Executive
Order
to
include
regulations
that
have
A
substantial
direct
effects
on
the
States,
on
the
relationship
between
the
national
government
and
the
States,

or
on
the
distribution
of
power
and
responsibilities
among
the
various
levels
of
government.@
45
Today
=

s
final
amendment
does
not
have
federalism
implications.
It
will
not
have
substantial
direct
effects
on
the
States,
on
the
relationship
between
the
national
government
and
the
States,
or
on
the
distribution
of
power
and
responsibilities
among
the
various
levels
of
government,

as
specified
in
Executive
Order
13132.
Thus,
Executive
Order
13132
does
not
apply
to
the
final
amendment.

F.
Executive
Order
13175:
Consultation
and
Coordination
with
Indian
Tribal
Governments
Executive
Order
13175,
entitled
A
Consultation
and
Coordination
with
Indian
Tribal
Governments
@

(
65
FR
67249,

November
9,
2000),
requires
EPA
to
develop
an
accountable
process
to
ensure
A
meaningful
and
timely
input
by
tribal
officials
in
the
development
of
regulatory
policies
that
have
tribal
implications.@
The
final
amendment
does
not
have
tribal
implications
as
specified
in
Executive
Order
13175.
It
will
not
have
substantial
direct
effects
on
tribal
governments,
on
the
relationship
between
the
Federal
government
and
Indian
tribes,
or
on
the
distribution
of
power
and
responsibilities
between
the
Federal
government
and
Indian
tribes,
as
specified
in
Executive
Order
13175.

Thus,
Executive
Order
13175
does
not
apply
to
today
=

s
final
amendment.
46
G.
Executive
Order
13045:
Protection
of
Children
from
Environmental
Health
and
Safety
Risks
Executive
Order
13045
(
62
FR
19885,
April
23,
1997)

applies
to
any
rule
that:
(
1)
is
determined
to
be
A
economically
significant
@

as
defined
under
Executive
Order
12866
and
(
2)
concerns
an
environmental
health
or
safety
risk
that
EPA
has
reason
to
believe
may
have
a
disproportionate
effect
on
children.
If
the
regulatory
action
meets
both
criteria,
EPA
must
evaluate
the
environmental
health
or
safety
effects
of
the
planned
rule
on
children,
and
explain
why
the
planned
regulation
is
preferable
to
other
potentially
effective
and
reasonably
feasible
alternatives
considered
by
EPA.

The
final
amendment
is
not
subject
to
the
Executive
Order
because
it
is
not
economically
significant
as
defined
in
Executive
Order
12866
and
because
EPA
does
not
have
reason
to
believe
the
environmental
health
or
safety
risks
addressed
by
this
action
present
a
significant
disproportionate
risk
to
children.

H.
Executive
Order
13211:
Actions
Concerning
Regulations
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
The
final
amendment
is
not
subject
to
Executive
Order
13211
(
66
FR
28355,
May
22,
2001)
because
it
is
not
an
47
economically
significant
regulatory
action
under
Executive
Order
12866.

I.
National
Technology
Transfer
Advancement
Act
As
noted
in
the
proposed
rule,
section
12(
d)
of
the
National
Technology
Transfer
and
Advancement
Act
of
1995
(
NTTAA),
Public
Law
No.
104­
113,
(
15
U.
S.
C.
272
note)

directs
EPA
to
use
voluntary
consensus
standards
(
VCS)
in
its
regulatory
activities,
unless
to
do
so
would
be
inconsistent
with
applicable
law
or
otherwise
impractical.

The
VCS
are
technical
standards
(
e.
g.,
materials
specifications,
test
methods,
sampling
procedures,
and
business
practices)
that
are
developed
or
adopted
by
VCS
bodies.
The
NTTAA
directs
EPA
to
provide
Congress,
through
OMB,
explanations
when
the
Agency
does
not
use
available
and
applicable
VCS.
The
final
amendment
does
not
involve
technical
standards.
Therefore,
EPA
is
not
considering
the
use
of
any
VCS.

J.
Congressional
Review
Act
The
Congressional
Review
Act,
5
U.
S.
C.
801,
et
seq.,
as
added
by
the
Small
Business
Regulatory
Enforcement
Act
of
1996,
generally
provides
that
before
a
rule
may
take
effect,

the
agency
promulgating
the
rule
must
submit
a
rule
report,
NESHAP
for
Industrial
Process
Cooling
Towers:
Final
Amendment­­
Page
48
of
49
which
includes
a
copy
of
the
rule,
to
each
House
of
the
Congress
and
to
the
Comptroller
General
of
the
United
States.
EPA
will
submit
a
report
containing
the
final
rule
and
other
required
information
to
the
United
States
Senate,

the
United
States
House
of
Representatives,
and
the
Comptroller
General
of
the
United
States
prior
to
publication
of
the
final
rule
in
the
Federal
Register.
A
major
rule
cannot
take
effect
until
60
days
after
it
is
published
in
the
Federal
Register.
This
action
is
not
a
"
major
rule"
as
defined
by
5
U.
S.
C.
804(
2).
The
final
amendment
is
effective
on
[
INSERT
DATE
OF
PUBLICATION
OF
FINAL
AMENDMENT
IN
THE
FEDERAL
REGISTER].

List
of
Subjects
in
40
CFR
Part
63
Environmental
protection,
Air
pollution
control,

Hazardous
substances,
Reporting
and
recordkeeping
requirements.

_________________
Dated:

______________________
Stephen
L.
Johnson,
Administrator.
49
For
the
reasons
stated
in
the
preamble,
title
40,

chapter
I,
part
63
of
the
Code
of
Federal
Regulations
is
amended
as
follows:

PART
63­ [
AMENDED]

1.
The
authority
citation
for
part
63
continues
to
read
as
follows:

Authority:
42
U.
S.
C.
7401,
et
seq.

Subpart
Q ­[
Amended]

2.
Section
63.400
is
amended
by
revising
paragraph
(
a)

to
read
as
follows:

§
63.400
Applicability.

(
a)
The
provisions
of
this
subpart
apply
to
all
new
and
existing
industrial
process
cooling
towers
that
are
operated
with
chromium­
based
water
treatment
chemicals
and
are
either
major
sources
or
are
integral
parts
of
facilities
that
are
major
sources
as
defined
in
§
63.401.

*
*
*
*
*