Document ID: EPA-HQ-OAR-2002-0058-0729
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-01-05T05:00Z

OAR­
2002­
0058
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial/
Commercial/
Institutional
Boilers
and
Process
Heaters:
Reconsideration
Summary
of
Public
Comments
and
Responses
Contract
No.
68­
D­
01­
081
Work
Assignment
No.
4­
08
U.
S.
Environmental
Protection
Agency
Office
of
Air
Quality
Planning
and
Standards
Emission
Standards
Division
Research
Triangle
Park,
North
Carolina
27711
December
14,
2005
i
Disclaimer
This
report
has
been
reviewed
by
the
Emission
Standards
Division
of
the
Office
of
Air
Quality
Planning
and
Standards,
and
EPA,
and
approved
for
publication.
Mention
of
trade
names
or
commercial
products
is
not
intended
to
constitute
endorsement
or
recommendation
for
use.
ii
TABLE
OF
CONTENTS
Chapter
Page
1
Background
Information
...................................................................................
1
2
Public
Comments
Received
...............................................................................
2
3
Methodology
and
Criteria
for
Demonstrating
Eligibility.................................
6
3.1
Monitoring
Alternative
.............................................................................
6
3.2
Disease
Registry
.......................................................................................
7
3.3
General
Approval
.....................................................................................
7
3.4
HI
and
HQ
values
.....................................................................................
9
4
Tiered
Risk
Assessment
Methodology.............................................................
12
4.1
General
Support
.....................................................................................
12
4.2
Guidance
................................................................................................
13
5
Look­
up
Tables
................................................................................................
15
5.1
Appropriate
use
of
a
Look­
up
Table
.......................................................
15
5.2
Stack
Height...........................................................................................
17
5.3
Distance
to
Property...............................................................................
20
6
Site­
Specific
Assessment
..................................................................................
22
7
Background
Emissions/
Co­
located
Emissions.................................................
26
8
Health­
Based
Compliance
Alternative
for
Metals
..........................................
35
9
Deadline
for
Submission
of
Eligibility
Demonstration
...................................
43
10
Proposed
Corrections.......................................................................................
47
11
Review
of
Eligibility
Demonstrations
for
Health­
Based
Compliance
Alternatives
and
Title
V
Permit
Conditions
...................................................
52
11.1
Eligibility
and
Permit
Authority
Review
..................................................
52
11.2
Significant
Permit
Modifications
.............................................................
55
11.3
Enforceable
Parameters
..........................................................................
57
iii
TABLE
OF
CONTENTS
(
Continued)

Chapter
Page
12
Miscellaneous
...................................................................................................
61
12.1
Wording
Changes/
Additions
...................................................................
61
12.2
Decision
to
Adopt
Health­
based
Compliance
Alternatives
.......................
61
12.3
Effects
on
Energy
Supplies
.....................................................................
66
12.4
Reference
Values
(
RVs)
........................................................................
66
12.5
Self­
Monitoring
......................................................................................
67
12.6
Other
Petitioner
Issues............................................................................
67
12.7
State
Resources
......................................................................................
68
12.8
Point
of
Maximum
Impact
......................................................................
69
12.9
Fire
Tube
Boilers....................................................................................
70
12.10
Test
Plans...............................................................................................
70
LIST
OF
TABLES
Table
Page
2­
1.
List
of
Commenters
for
the
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial/
Commercial/
Institutional
Boilers
and
Process
Heaters.................
2
1
Chapter
1
Background
Information
Section
112
(
c)(
2)
of
the
Clean
Air
Act
mandates
that
the
Environmental
Protection
Agency
(
EPA)
establish
emission
standards
for
hazardous
air
pollutants
(
NESHAP)
for
control
of
HAP
from
both
existing
and
new
major
sources
based
upon
the
criteria
set
out
in
CAA
section
112(
d).

On
September
13,
2004,
EPA
promulgated
national
emission
standards
for
hazardous
air
pollutants
(
NESHAP)
for
industrial,
commercial,
and
institutional
boilers
and
process
heaters.

Following
the
promulgation
of
the
final
rule,
EPA
received
petitions
for
reconsideration
pursuant
to
section
307(
d)(
7)(
B)
of
the
CAA
from
the
Natural
Resources
Defense
Council
(
NRDC),

Environmental
Integrity
Project
(
EIP),
and
General
Electric
(
GE).
On
January
28,
2005,
EPA
sent
a
letter
to
NRDC
and
EIP
notifying
the
parties
of
the
intent
to
grant
their
petition
for
reconsideration.
On
June
27,
2005,
EPA
published
a
Federal
Register
notice
granting
reconsideration
and
soliciting
comments
on
certain
provisions
used
to
demonstrate
eligibility
for
the
health­
based
compliance
alternatives
outlined
in
appendix
A
of
the
final
rule,
and
on
the
provisions
for
the
health­
based
compliance
alternative
for
total
selected
metals
reflected
in
§
63.7507(
b)
of
the
final
rule.
EPA
did
not
grant
reconsideration
on
the
other
issues
raised
by
the
petitioners.

Thirty­
six
public
submissions
were
received
from
a
wide
variety
of
sources,
consisting
mainly
of
government
agencies,
environmental
organizations,
industry
associations,
and
owner/
operators
of
affected
boilers
and
process
heaters.
All
of
the
comments
that
were
submitted
and
the
responses
to
these
comments
are
summarized
in
this
document.
This
summary
is
the
basis
for
the
revisions
made
to
the
final
rule
amendments
between
proposal
and
promulgation.
2
Chapter
2
Public
Comments
Received
The
EPA
received
a
total
of
37
submissions
commenting
on
the
reconsideration
notice
for
the
industrial,
commercial
and
institutional
boilers
and
process
heaters
NESHAP,
some
of
which
contained
attachments.
A
list
of
commenters,
their
affiliations,
and
the
EPA
docket
item
number
assigned
to
their
correspondence
is
provided
in
Table
2­
1.
To
achieve
an
organized
presentation,

we
have
grouped
the
comments
by
topic
in
Chapters
3
through
8
of
this
document.

Table
2­
1.
List
of
Commenters
for
the
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial/
Commercial/
Institutional
Boilers
and
Process
Heaters
(
OAR­
2002­
0058)

Docket
No.
Commenter's
Name
and
Addressa
OAR­
2002­
0058­
0660
E.
M.
T.
O'Nan,
Director,
Protect
All
Children's
Environment
­
Public
Comment
OAR­
2002­
0058­
0662
John
Bradfield,
Director
of
Environmental
Affairs,
Composite
Panel
Association
(
CPA)
Public
Comment
OAR­
2002­
0058­
0663
Comment
submitted
by
Timothy
G.
Hunt,
Senior
Director,
Air
Quality
Programs,
American
Forest
&
Paper
Association
­
Public
Comment
OAR­
2002­
0058­
0664
American
Forest
&
Paper
Association
Comment
­
Public
Comment
Attachment
OAR­
2002­
0058­
0665
Donald
R.
Schregardus,
Deputy
Assistant
Secretary
of
the
Navy
(
Installations
and
Environment)
on
behalf
of
Clean
Air
Act
Services
Steering
Committee
­
Public
Comment
OAR­
2002­
0058­
0666
Julia
E.
Smith,
Amundsen
&
Gilroy
,
P.
A.,
Attorneys
at
Law
on
behalf
of
Coastal
Lumber
Company,
Hood
Industries,
Inc.
and
Scotch
Lumber
Company
(
collectively,
"
Companies")
­
Public
Comment
OAR­
2002­
0058­
0667
Michel
R.
Benoit,
Executive
Director,
Cement
Kiln
Recycling
Coalition
(
CKRC)
­
Public
Comment
3
Table
2­
1.
List
of
Commenters
for
the
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial/
Commercial/
Institutional
Boilers
and
Process
Heaters
(
OAR­
2002­
0058)

Docket
No.
Commenter's
Name
and
Addressa
OAR­
2002­
0058­
0668
Erik
G.
Milito,
Senior
Attorney,
Office
of
General
Counsel,
American
Petroleum
Institute
­
Public
Comment
OAR­
2002­
0058­
0669
Carl
Johnson,
Executive
Director,
Southern
Pressure
Treaters
Association
and
Jeffrey
Miller,
Executive
Director,
Treated
Wood
Council
­
Public
Comment
­

OAR­
2002­
0058­
0670
Thomas
W.
Easterly,
Commissioner,
Indiana
Department
of
Environmental
Management
­
Public
Comment
OAR­
2002­
0058­
0671
Robert
D.
Bessette
on
behalf
of
the
Council
of
Industrial
Boiler
Owners
(
CIBO)
­
Public
Comment
OAR­
2002­
0058­
0672
Bob
Elam,
Director,
Environment,
American
Chemistry
Council
­
Public
Comment
OAR­
2002­
0058­
0673
Comment
submitted
by
Laurie
L.
Zeinio,
Director,
Safety,
Environment,
Standards&
E­
PDP,
Deere
&
Company
­
Public
Comment
OAR­
2002­
0058­
0674
Thomas
W.
Rockwood,
Coastal
Plywood
Company
­
Public
Comment
OAR­
2002­
0058­
0675
Randy
Meyer,
Manager
of
Environmental
Affairs,
American
Municipal
Power
­
Ohio
­
Public
Comment
OAR­
2002­
0058­
0676
Bradley
M.
Campbell,
Commissioner,
Department
of
Environmental
Protection,
State
of
New
Jersey
­
Public
Comment
OAR­
2002­
0058­
0677
William
O'Sullivan,
Director,
Department
of
Environmental
Protection,
State
of
New
Jersey
­
Public
Comment
OAR­
2002­
0058­
0678
Bruce
Alexius,
Air
Resource
Leader,
Regulatory
Affairs
Expertise
Center,
The
Dow
Chemical
Company
­
Public
Comment
OAR­
2002­
0058­
0679
Dennis
Steiner,
Mayor,
City
of
Orrville,
Ohio
­
Public
Comment
OAR­
2002­
0058­
0680
Norbert
Dee,
Ph.
D.
Director
Environment
&
Safety,
National
Petrochemical
&
Refiners
Assoc.
(
NPRA)
­
Public
Comment
OAR­
2002­
0058­
0681
Eric
Clark,
Synthetic
Organic
Chemical
Manufacturers
Association
(
SOCMA)
­
Public
Comment
OAR­
2002­
0058­
0682
David
A.
Buff,
P.
E.,
Q.
E.
P.,
Principal
Engineer,
Golder
Associates
Inc.
on
behalf
of
Florida
Sugar
Industry
(
FSI)
­
Public
Comment
4
Table
2­
1.
List
of
Commenters
for
the
National
Emission
Standards
for
Hazardous
Air
Pollutants
for
Industrial/
Commercial/
Institutional
Boilers
and
Process
Heaters
(
OAR­
2002­
0058)

Docket
No.
Commenter's
Name
and
Addressa
OAR­
2002­
0058­
0683
Lloyd
L.
Eagan,
Chair,
STAPPA
Air
Toxics
Committee
and
Robert
H.
Colby,
Chair,
ALAPCO
Air
Toxics
Committee
­
Public
Comment
OAR­
2002­
0058­
0684
David
Wright,
Air
Toxics
&
Inventory
Program,
Bureau
of
Air
Quality,
Maine
Department
of
Environmental
Protection
(
Part
1
of
3)
­
Public
Comment
OAR­
2002­
0058­
0685
David
Wright,
Air
Toxics
&
Inventory
Program,
Bureau
of
Air
Quality,
Maine
Department
of
Environmental
Protection
(
Part
2
of
3)
­
Public
Comment
OAR­
2002­
0058­
0686
David
Wright,
Air
Toxics
&
Inventory
Program,
Bureau
of
Air
Quality,
Maine
Department
of
Environmental
Protection
(
Part
3
of
3)
Public
Comment
OAR­
2002­
0058­
0687
Bill
Perdue,
Vice­
President,
Environmental,
Health/
Safety
Standards,
American
Home
Furnishings
Alliance
(
AHFA)
­
Public
Comment
OAR­
2002­
0058­
0688
Valerie
Ughetta,
Director
of
Stationary
Sources,
Alliance
of
Automobile
Manufacturers
­
Public
Comment
OAR­
2002­
0058­
0689
Valerie
Ughetta,
Director,
Stationary
Sources,
Alliance
of
Automobile
Manufacturers
­
Public
Comment
Attachment
OAR­
2002­
0058­
0690
Valerie
Ughetta,
Director
of
Stationary
Sources,
Alliance
of
Automobile
Manufacturers
­
Public
Comment
OAR­
2002­
0058­
0691
Melvin
Keener,
Ph.
D.,
Executive
Director,
Coalition
for
Responsible
Waste
Incineration
(
CRWI)
­
Public
Comment
OAR­
2002­
0058­
0692
J.
W.
Hunter,
Mayor,
City
of
Shelby,
Ohio
­
Comment
Response
OAR­
2002­
0058­
0693
John
Walke,
Natural
Resources
Defense
Council
­
Public
Comment
OAR­
2002­
0058­
0694
L.
Eagan,
Director,
Bureau
of
Air
Management,
State
of
Wisconsin,
Department
of
Natural
Resources
­
Public
Comment
OAR­
2002­
0058­
0695
National
Association
of
Manufacturers
­
Public
Comment
OAR­
2002­
0058­
0696
Richard
Homrighausen,
Mayor,
City
of
Dover,
Ohio
­
Public
Comment
OAR­
2002­
0058­
0697
Michael
L.
Weadcock,
Director
of
Public
Service
and
Safety,
City
of
St.
Marys,
Ohio
OAR­
2002­
0058­
0698
Rita
C.
McMahon,
City
Manager,
City
of
Painesville,
Ohio
5
a
Commenters
listed
multiple
times
due
to
duplicate
comments
and
attachments
are
referred
to
in
Chapters
3
through
11
of
this
document
by
the
first
number
that
was
assigned
to
that
commenter
in
the
docket.
6
Chapter
3
Methodology
and
Criteria
for
Demonstrating
Eligibility
3.1
Monitoring
Alternative
Comment:
One
commenter
(
OAR­
2002­
0058­
0660)
recommended
an
epidemiological
study
in
each
affected
area
to
determine
a
baseline
level
of
health.
One
commenter
(
OAR­
2002­

0058­
0680)
recommended
two
years
of
continuous
air
monitoring
at
all
facilities
eligible
for
health­
based
compliance
alternatives
in
order
to
justify
the
determination
for
health
risk
established
in
these
health­
based
compliance
alternatives.

Response:
We
disagree
with
the
commenters'
recommendations.
Procedures
for
risk
assessments
in
appendix
A
are
based
on
the
risk
assessment
methodologies
and
dispersion
models
that
are
outlined
in
the
1999
Residual
Risk
Report
to
Congress
(
EPA­

453/
R­
99­
001).
As
directed
by
the
Clean
Air
Act,
we
prepared
this
report
to
outline
an
approach
for
calculating
risk
after
implementation
of
the
MACT
standards.
In
the
1999
report
we
identified
uncertainties
in
risk
assessment
methodologies
and
made
recommendations
for
any
legislative
changes
needed.
We
indicated
that
data
from
epidemiological
studies
will
rarely
be
available
for
evaluating
correlations
between
exposure
and
adverse
human
health
effects.
Accordingly,
the
1999
report
also
indicates
that
we
rely
on
a
variety
of
air
dispersion
models
(
e.
g.,
SCREEN
3)
to
assess
exposure
to
HAP.
In
the
report,
we
proposed
no
legislative
changes
to
the
Clean
Air
Act.
After
reviewing
the
1999
report,
the
Congress
did
not
change
the
residual
risk
requirements
in
the
Clean
Air
Act,
thereby
indicating
approval
of
the
methods
we
outlined
in
the
report
for
calculating
the
risk
posed
by
facilities.
The
methods
outlined
in
the
report
to
develop
the
health­
based
standards
under
section
112
are
primarily
based
on
dispersion
modeling.
We
see
no
reason
to
depart
from
this
strategy
for
the
health­
based
compliance
alternatives.

Additionally,
the
commenters
have
not
provided
any
specific
justification
to
support
their
recommendations.
7
3.2
Disease
Registry
Comment:
One
commenter
(
OAR­
2002­
0058­
0660)
suggested
establishing
a
disease
registry
to
serve
as
a
baseline
for
monitoring
the
effects
of
this
regulation
on
the
health
conditions
of
sensitive
populations
(
TILT,
asthma,
ADD/
ADHD),
and
requested
particular
monitoring
of
behavioral
and
criminal
activities
in
areas
where
manganese
emissions
are
permitted
as
a
result
of
the
health­
based
compliance
alternatives.

Response:
We
disagree
with
the
commenter's
suggestion.
As
stated
above,
it
is
appropriate
to
apply
our
risk
assessment
methodology
to
the
health­
based
alternative
compliance
options
in
the
present
rule.
Part
of
that
methodology
is
the
reliance
on
reference
values
(
e.
g.,
Reference
Concentrations
(
RfCs))
that
are
based
on
relevant
health
endpoints
and
that
are
designed
to
be
protective
of
sensitive
populations.
These
reference
values
form
the
basis
of
the
health­
based
compliance
alternatives
in
appendix
A.
EPA
proposed
to
use
the
reference
values
to
establish
health­
based
alternatives
in
the
notice
of
proposed
rulemaking
and
provided
an
opportunity
to
comment.
After
considering
public
comments,
we
continued
to
support
the
use
of
RfCs
for
this
application.
EPA
did
not
grant
reconsideration
on
our
decision
to
use
the
RfCs.

3.3
General
Approval
Comment:
Multiple
commenters
(
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681,
OAR­

2002­
0058­
0682,
OAR­
2002­
0058­
0695,
OAR­
2002­
0058­
0687,
OAR­
2002­
0058­
0669,
OAR­

2002­
0058­
0665,
OAR­
2002­
0058­
0673,
OAR­
2002­
0058­
0667,
OAR­
2002­
0058­
0668,
OAR­

2002­
0058­
0671,
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0696,
OAR­

2002­
0058­
0697,
OAR­
2002­
0058­
0698,
OAR­
2002­
0058­
0688)
supported
the
methodology
and
criteria
used
to
develop
the
health­
based
compliance
alternatives
for
HCl
and
manganese
and
cited
several
reasons.
Two
commenters
(
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681)
stated
that
risk
assessment,
as
applied
by
agencies
within
the
Federal
government,
is
the
scientifically
appropriate,
precautionary
method
for
assessing
the
likelihood
that
exposure
is
associated
with
adverse
health
and
for
ensuring
public
health
with
an
ample
margin
of
safety.
The
commenters
suggested
that
risk
assessment
is
scientifically
appropriate
because
the
methodology
correctly
applied
the
four
steps
of
the
risk
paradigm
in
the
tiered
approach.
The
commenters
also
suggested
that
risk
assessment
is
precautionary
because
it
does
not
underestimate
the
true
risks
of
8
actual
exposure.
One
commenter
(
OAR­
2002­
0058­
0682)
added
that
the
methodology
for
demonstrating
eligibility
for
health­
based
compliance
alternatives
is
based
on
accepted
techniques
for
risk
assessment
which
have
withstood
judicial
review.
One
commenter
(
OAR­
2002­
0058­

0695)
supported
a
standard
that
attuned
to
the
variability
of
sources
regulated
by
this
MACT
standard.
The
commenter
added
that
this
methodology
heeded
to
Congress'
feasibility
concern
and
public
health
mandate.

Three
commenters
(
OAR­
2002­
0058­
0687,
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­

0681)
emphasized
the
precedent
of
the
use
of
air
dispersion
models
for
regulatory
decisions
at
EPA
and
supported
the
conservative
estimates
reflected
by
the
SCREEN
3
dispersion
model
used
for
the
look­
up
tables
as
well
as
the
site­
specific
information
in
the
ISCSTC
model.
Two
of
these
commenters
(
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681)
provided
examples
of
air
dispersion
modeling
regulatory
decisions
such
as
the
New
Source
Review/
Prevention
of
Significant
Deterioration
Programs
and
the
section
112(
r)
accidental
release
programs.

Response:
We
agree
with
the
use
of
a
risk
assessment
methodologies
as
applied
in
appendix
A.
These
methodologies
rely
on
scientifically­
accepted
peer­
reviewed
methodologies
and
the
compliance
alternatives
remain
protective
of
the
public
health.
We
also
acknowledge
the
commenters'
general
support
for
the
methodology
in
appendix
A
and
recognition
of
previous
use
of
dispersion
modeling
in
other
EPA
regulations
and
programs.

The
1999
EPA
Residual
Risk
Report
to
Congress
lists
the
SCREEN
3
air
dispersion
model
as
an
example
model
for
simple
types
of
applications,
such
as
the
first­
tier
look­
up
assessment
in
appendix
A.
This
model
and
the
ISCSTC
are
referenced
in
the
Air
Toxics
Risk
Assessment
(
ATRA)
Reference
Library,
which
supports
our
decision
to
incorporate
these
dispersion
models
into
these
health­
based
compliance
alternatives
of
appendix
A.

We
are
retaining
the
health­
based
compliance
alternatives
in
substantially
the
same
form.
However,
we
are
making
a
limited
number
of
amendments
to
section
63.7507
and
appendix
A
of
subpart
DDDDD
to
improve
and
clarify
the
process
for
demonstrating
eligibility
to
comply
with
the
health­
based
compliance
alternatives
contained
in
the
rule.

These
amendments
include
the
following:
(
1)
When
performing
a
lookup
table
analysis,

affected
sources
with
multiple
emission
points
will
now
use
a
toxicity­
and
emissionsweighted
stack
height
as
opposed
to
the
average
stack
height.
New
equations
have
been
added
to
appendix
A;
(
2)
We
corrected
the
rule
to
clarify
that
all
units,
as
opposed
to
only
9
large
solid­
fuel
fired
units,
may
demonstrate
eligibility
for
the
heath­
based
alternatives;
(
3)

explicit
language
has
been
added
to
clarify
that
the
permitting
agencies
have
the
authority
to
review
eligibility
demonstrations
to
verify
that
they
meet
the
requirements
of
Appendix
A
and
are
technically
sound;
and
(
4)
the
list
of
enforceable
parameters
that
can
potentially
be
included
in
the
Title
V
permit
has
been
extended
to
explicitly
include
the
term
HAP
emission
rate
and
non­
process
parameters.
These
and
other
amendments
are
discussed
further
in
other
sections
of
this
document
and
the
associated
notice
published
in
the
Federal
Register.

3.4
HI
and
HQ
Values
Comment:
Multiple
commenters
(
OAR­
2002­
0058­
0665,
OAR­
2002­
0058­
0666,
OAR­

2002­
0058­
0667,
OAR­
2002­
0058­
0668,
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681,
OAR­

2002­
0058­
0673,
OAR­
2002­
0058­
0674,
OAR­
2002­
0058­
0682,
OAR­
2002­
0058­
0695)
agreed
that
the
HQ
and
HI
values
of
1.0
are
appropriate,
well
established,
and
protective
of
public
health
with
an
ample
margin
of
safety.
One
commenter
(
OAR­
2002­
0058­
0665)
suggested
that
facilities
who
have
initiated
demonstrations
for
health­
based
compliance
alternatives
have
done
so
using
the
HI
value
of
1.0
and
a
change
of
value
would
require
these
facilities
to
re­
do
their
risk
assessments.
Two
commenters
(
OAR­
2002­
0058­
0673,
OAR­
2002­
0058­
0667)
emphasized
the
conservative
nature
of
the
RFC
values
used
to
develop
these
index
values
to
protect
sensitive
populations.
One
commenter
(
OAR­
2002­
0058­
0668)
attached
the
2003
report
by
the
Residual
Risk
Coalition
entitled
"
EPA
Should
Set
Risk­
Based
Emission
Levels
For
Threshold
Hazardous
Air
Pollutants
At
Appropriate
Levels
Above
A
Hazard
Index
Of
1.0"
to
support
the
decision
to
not
adjust
the
HI
value
to
less
than
1.0
and
justify
HI
values
greater
than
1.0
when
providing
for
an
ample
margin
of
safety.
One
commenter
(
OAR­
2002­
0058­
0681)
contended
that
adopting
an
HI
index
of
2.0
would
unlikely
result
in
any
significant
change
in
the
protection
of
public
health.

Two
commenters
(
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0691)
suggested
that
EPA
provide
for
flexibility
and
engineering
judgment
in
interpreting
an
applicability
cutoff
HI
or
HQ
of
greater
than
1.0
in
individual
situations.
One
commenter
(
OAR­
2002­
0058­
0691)
stated
that
a
value
of
1.0
is
the
most
stringent
margin
of
safety
required
and
the
Agency
could
use
HI's
greater
than
1.0
in
certain
cases.
The
commenter
added
that
no
additional
margin
of
safety
is
required
because
the
RfC
calculation
contain
many
layers
of
protection
including
safety
factors
of
300
for
10
HCl,
and
1000
for
Mn,
respectively,
to
account
for
uncertainty.
One
commenter
(
OAR­
2002­

0058­
0688)
added
that
at
present
HI
and
HQ
values
are
not
transferable
to
a
probability
of
a
person
incurring
a
non­
carcinogenic
adverse
effect.

One
commenter
(
OAR­
2002­
0058­
0684)
suggested
the
use
of
an
applicability
cutoff
HI
or
HQ
value
of
at
most
0.5
in
order
to
account
for
cumulative
and
persistent
risk.

Response:
We
disagree
that
an
HI
or
HQ
value
other
than
1.0
should
be
used
as
an
applicability
cutoff
value
for
the
health­
based
compliance
alternatives.
HI
and
HQ
values
are
based
on
peer
reviewed
reference
values
such
as
the
EPA's
reference
concentrations
(
RfC).
An
RfC
is
an
estimate
(
with
uncertainty
spanning
perhaps
an
order
of
magnitude)

of
a
continuous
inhalation
exposure
or
a
daily
exposure
to
the
human
population
(
including
sensitive
subgroups)
that
is
likely
to
be
without
an
appreciable
risk
of
deleterious
noncancer
effects
during
a
lifetime.
An
HI
or
HQ
less
than
or
equal
to
one
means
that
the
concentration
of
the
pollutant
(
in
air)
is
less
than
or
equal
to
the
reference
value,
and,

therefore,
is
presumed
to
be
without
appreciable
risk
of
adverse
health
effects.

As
mentioned
by
commenters,
RfC
values
contain
uncertainty
factors
in
order
to
account
for
scientific
uncertainties
that
are
identified
in
the
literature.
We
acknowledge
that
EPA
can
consider
the
uncertainty
inherent
in
these
reference
values
when
making
risk­
based
determinations.
For
the
health­
based
compliance
alternatives,
using
an
HI
and
HQ
of
one
as
a
health­
protrective
default
is
appropriate
and,
along
with
the
risk
assessment
methods
specified
in
appendix
A,
protects
public
health
with
an
ample
margin
of
safety
as
required
by
section
112(
d)(
4).

Comment:
One
commenter
(
OAR­
2002­
0058­
0678)
did
not
support
the
use
of
a
HI
less
than
or
equal
to
1.0
as
the
applicability
cutoff
value
for
determining
eligibility
with
the
HCl
healthbased
compliance
alternative.
The
commenter
asserted
that
the
HI
should
be
changed
to
less
than
10
but
greater
than
1.0
due
to
the
additive
effect
of
several
health
protective
factors,
such
as
RfCs
and
the
individual
most
exposed
metric
used
for
deriving
the
HCl
HI
value.
Specifically,
the
commenter
highlighted
that
it
is
overly
conservative
to
apply
the
chlorine
RfC
to
evaluate
the
exposure
to
chlorine.
The
commenter
added
that
chlorine
reacts
in
the
atmosphere
to
form
HCl,

and
the
commenter
requested
EPA
to
evaluate
the
exposure
to
chlorine
using
the
equivalent
amount
of
HCl
formed
in
the
atmospheric
reactions.
11
Response:
As
we
argue
above,
we
disagree
that
an
HI
or
HQ
value
other
than
1.0
should
be
used
as
an
applicability
cutoff
value
for
the
health­
based
alternative
compliance
alternatives.
An
HI
of
1.0
corresponds
to
a
level
of
pollutant
exposure
that
is
unlikely
to
result
in
adverse
health
effects
over
a
lifetime.
We
acknowledge
that
EPA
can
consider
the
uncertainty
inherent
in
reference
values
when
making
risk­
based
determinations.

However,
for
the
health­
based
compliance
alternatives,
using
an
HI
and
HQ
of
1.0
as
a
health­
based
protective
default
is
appropriate
and
helps
protect
public
health
with
an
ample
margin
of
safety.

Additionally,
as
stated
above,
it
is
appropriate
to
apply
our
risk
assessment
methodology
to
the
health­
based
alternative
compliance
options
in
the
present
rule.
This
methodology
includes
calculating
hazard
to
the
individual
most
exposed
to
pollutant
emissions
from
the
source,
which
helps
ensure
that
public
health
is
protected
with
an
ample
margin
of
safety.

We
also
disagree
with
the
commenter's
suggestion
to
account
for
atmospheric
reactions
of
chlorine
to
form
HCl.
Impacts
from
chlorine
can
occur
shortly
after
release
if
a
population
lives
near
an
emission
point.
Chlorine
has
a
lower
reference
value
than
HCl.

Thus,
we
make
the
health­
protective
assumption
that
people
are
exposed
to
chlorine
emitted
from
the
source
prior
to
any
conversion
into
the
less
potent
HCl.
This
approach,

along
with
the
other
requirements
of
appendix
A,
helps
ensure
that
public
health
is
protected
with
an
ample
margin
of
safety.
12
Chapter
4
Tiered
Risk
Assessment
Methodology
4.1
General
Support
Comment:
Multiple
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0680,
OAR­

2002­
0058­
0681,
OAR­
2002­
0058­
0695,
OAR­
2002­
0058­
0671,
OAR­
2002­
0058­
0667,
OAR­

2002­
0058­
0688,
OAR­
2002­
0058­
0682,
OAR­
2002­
0058­
0666,
OAR­
2002­
0058­
0673,
OAR­

2002­
0058­
0670,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­

2002­
0058­
0697,
OAR­
2002­
0058­
0698,
OAR­
2002­
0058­
0674,
OAR­
2002­
0058­
0675,
OAR­

2002­
0058­
0672,
OAR­
2002­
0058­
0678)
supported
the
flexibility
and
efficient
use
of
both
industry
and
permitting
authority
resources
provided
for
in
a
tiered
risk
assessment
methodology.

These
commenters
added
that
this
flexibility
is
appropriately
balanced
with
conservatism
and
accuracy
to
protect
the
public
health
with
an
ample
margin
of
safety.
One
commenter
(
OAR­

2002­
0058­
0663)
specifically
approved
of
the
efficiency
of
this
tiered
approach
because
it
implements
simple
screening
techniques
as
compared
to
time
intensive
analyses,
for
facilities
that
are
low­
risk,
even
under
worse­
case
scenarios.
One
commenter
(
OAR­
2002­
0058­
0687)
added
that
the
tiered
approach
provides
a
simple,
conservative
first
tier
analysis
that
companies
can
achieve
without
hiring
an
outside
consultant
to
demonstrate
compliance
with
the
health­
based
compliance
alternative.
This
commenter
also
feels
it
is
necessary
to
allow
facilities
to
conduct
site­
specific
analyses
in
tandem
with
the
look­
up
analysis
so
that
facilities
can
still
demonstrate
compliance
with
the
health­
based
alternatives
in
the
event
that
the
source
fails
the
look­
up
analysis.
One
commenter
(
OAR­
2002­
0058­
0687)
added
it
is
necessary
to
allow
facilities
to
conduct
more
specific
analyses
for
the
health­
based
compliance
alternative
eligibility
demonstration.
The
commenter
anticipated
some
furniture
manufacturers
will
use
the
ISCST3
model
to
comply
with
the
second
tier.
One
commenter
(
OAR­
2002­
0058­
0681)
added
that
a
tiered
approach
is
less
arbitrary
than
a
control­
based
standard,
which
requires
equivalent
controls
across
the
board
without
considering
the
risk
of
an
affected
source.
One
commenter
(
OAR­
2002­

0058­
0670)
specifically
approved
of
estimating
long
term
inhalation
exposure
through
the
13
estimation
of
annual
or
multi­
year
ambient
concentrations.
Four
commenters
(
OAR­
2002­
0058­

0672,
OAR­
2002­
0058­
0681,
OAR­
2002­
0058­
0678,
OAR­
2002­
0058­
0682)
agree
the
procedures
set
forth
in
the
site­
specific
methodology
to
ensure
data
quality
control
including:

using
quality
assured
data
whenever
possible
and
using
health
protective
default
assumptions
in
the
absence
of
quality
assured
data
and
preparing
transparent,
replicable
documentation
of
the
assessment.

One
commenter
(
OAR­
2002­
0058­
0682)
contended
that
a
facility
that
fails
the
look­
up
test
and
opts
to
become
eligible
through
a
more
detailed
second
tier
does
not
imply
that
a
facility
will
cause
harm
to
the
public
health;
instead
this
tiered
approach
eliminates
these
facilities
that
have
no
impact
while
protecting
the
public
with
an
ample
margin
of
safety.

Several
commenters
(
OAR­
2002­
0058­
0682,
OAR­
2002­
0058­
0678,
OAR­
2002­
0058­

0688,
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0681,
OAR­
2002­
0058­
0680)
cited
the
precedence
and
consistency
of
a
tiered
risk
approach
in
EPA
modeling
of
air
toxics
and
mobile
sources
and
at
the
state
levels.
One
commenter
(
OAR­
2002­
0058­
0680)
specifically
cited
the
use
of
tiered
risk
methodologies
at
the
EPA
since
1992.

Response:
We
acknowledge
the
support
for
the
flexibility,
efficiency,
and
healthprotective
nature
of
a
tiered
approach
to
risk
assessment.
We
concluded
that
a
tiered
risk
approach
is
consistent
with
both
the
commenters'
support
for
an
approach
that
minimizes
the
impact
on
low­
risk
facilities
and
EPA's
statutory
mandate
under
§
112.

4.2
Guidance
Comment:
One
commenter
(
OAR­
2002­
0058­
0688)
recognized
the
procedural
importance
of
including
the
1992
document,
A
Tiered
Modeling
Approach
for
Assessing
the
Risks
Due
to
Sources
of
Hazardous
Air
Pollutants,
in
the
docket
since
the
document
was
referenced
in
the
proposed
rule.
However,
the
commenter
feels
that
many
aspects
of
this
earlier
guidance
document
have
been
superseded
by
more
recent
guidance,
such
as
the
Air
Toxics
Risk
Assessment
Reference
Library,
which
was
referenced
in
the
final
rule.
The
commenter
does
not
think
the
older
guidance
document
should
play
any
further
role
in
this
rule.

Response:
We
agree
that
the
Air
Toxics
Risk
Assessment
(
ATRA)
Reference
Library
represents
the
most
up­
to­
date
information
on
risk
assessment
methodologies.
We
placed
the
1992
document
in
the
docket
to
fulfill
procedural
requirements
of
the
public
14
rulemaking
process.
However,
many
relevant
aspects
of
the
1992
tiered
risk
assessment
document,
which
we
cited
in
the
proposed
rule,
are
incorporated
into
the
ATRA
Reference
Library,
which
is
cited
and
incorporated
by
reference
in
the
final
rule.
15
Chapter
5
Look­
up
Tables
5.1
Appropriate
use
of
a
Look­
up
Table
Comment:
Multiple
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0671,
OAR­

2002­
0058­
0672,
OAR­
2002­
0058­
0681,
OAR­
2002­
0058­
0680,
OAR­
2002­
0058­
0695,
OAR­

2002­
0058­
0682,
OAR­
2002­
0058­
0687,
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0675,
OAR­

2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­

2002­
0058­
0698)
supported
the
use
of
the
look­
up
tables
as
well
as
the
levels
of
protection
built
into
the
look­
up
tables;
the
commenters
suggested
that
the
tables
be
retained
without
modification.
These
commenters
agreed
that
the
tables
screen
out
sources,
considering
worse
case
scenarios,
which
do
not
pose
a
threat
to
human
health
or
the
environment.
Three
commenters
(
OAR­
2002­
0058­
0687,
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0682)
specified
that
the
analysis
used
to
develop
the
tables
accounts
for
worse­
case
scenarios
with
respect
to
parameters
including:
meteorology,
downwash,
terrain,
and
stack
parameters.
Three
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681)
discussed
the
adequate
levels
of
protection
inherent
in
the
safety
factors
of
the
RfCs.
These
commenters
explained
how
these
safety
factors
accounted
for
uncertainties
in
the
observable
effects
between
species
and
for
uncertainties
in
the
observable
effects
of
sensitive
populations,
as
well
as
uncertainties
due
to
limitations
in
the
toxics
database.
The
commenter
lists
the
safety
factors
for
the
two
threshold
pollutants
that
are
used
in
the
health­
based
compliance
alternatives:
300
for
HCl
and
1000
for
Mn.
Several
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­

0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­
2002­
0058­

0698)
specified
the
conservatism
of
the
maximally
exposed
individual
(
MEI)
metric
over
a
lifetime
and
cited
the
1997
report
by
the
Presidential/
Congressional
Commission
on
Risk
Assessment
and
Risk
Management
to
support
the
expert
scientific
opinion
on
the
levels
of
conservatism
in
the
individual
most
exposed
metric.
16
Two
commenters
(
OAR­
2002­
0058­
0673,
OAR­
2002­
0058­
0667)
agreed
with
using
source­
specific
look­
up
tables
and
added
that
given
the
availability
of
source­
specific
data,
and
stated
that
more
generic
look­
up
tables
are
not
warranted.

Four
commenters
(
OAR­
2002­
0058­
0681,
OAR­
2002­
0058­
0665,
OAR­
2002­
0058­

0688,
OAR­
2002­
0058­
0687)
suggested
that
these
tables
are
an
efficient
and
cost­
effective
screening
tool.
Two
commenters
(
OAR­
2002­
0058­
0665,
OAR­
2002­
0058­
0681)
added
that
these
tools
will
specifically
benefit
small
businesses,
with
a
smaller
amount
of
affected
sources,
by
providing
a
tool
to
evaluate
their
risk
without
spending
significant
resources.
One
commenter
(
OAR­
2002­
0058­
0687)
stated
that
the
tables
allow
for
sources
to
complete
their
assessment
without
hiring
third
party
consultants;
and
contended
that
the
tables
will
prevent
delays
resulting
from
bottlenecks
caused
by
the
limited
availability
of
third
parties
to
complete
site­
specific
assessments.

One
commenter
(
OAR­
2002­
0058­
0678)
supported
the
use
of
the
look­
up
tables
only
if
a
more
refined,
second
tier
approach
remains
as
part
of
the
rule.
The
commenter
suggested
that
the
look­
up
tables
over
predict
both
the
ambient
concentrations
of
HCl
or
Mn
and
the
health
hazards.

Four
commenters
(
OAR­
2002­
0058­
0677,
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­

0684,
OAR­
2002­
0058­
0694)
disagreed
with
use
of
the
look­
up
tables
due
to
an
insufficient
level
of
conservatism
inherent
in
the
look­
up
tables
during
worse­
case
scenarios.
These
commenters
emphasized
that
if
the
look­
up
tables
remained
as
a
result
of
this
reconsideration,
the
look
up
tables
should
not
be
used
when
unique
site­
specific
factors
are
not
accounted
for
in
the
tables.

Three
of
these
commenters
(
OAR­
2002­
0058­
0677,
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­

0684)
specified
that
the
tables
should
not
be
used
when
events
of
building
downwash
or
rain
caps,

or
complex
terrain
occurred.
One
commenter
(
OAR­
2002­
0058­
0677)
compared
the
MACT
health­
based
compliance
alternative
look­
up
tables
to
look­
up
tables
used
by
the
state
authority
and
stated
that
the
MACT
tables
do
not
cover
worse­
case
scenarios.
One
commenter
(
OAR­

2002­
0058­
0694)
noted
that
in
look­
up
tables
used
in
state
hazardous
air
pollutant
rules,
the
use
of
the
table
requires
that
the
stack
does
not
have
an
obstruction
such
as
a
rain
hat.
One
commenter
(
OAR­
2002­
0058­
0683)
requested
that
EPA
clarify
that
sources
must
comply
with
the
MACT
standard
in
the
event
that
a
permitting
agency
rejects
the
use
of
look­
up
table
analysis
for
demonstrating
eligibility
to
a
health­
based
compliance
alternative.
17
Response:
We
continue
to
believe
that
the
look­
up
tables
can
provide
an
efficient
and
cost­
effective
method
for
sources
to
comply
with
the
health­
based
alternative
compliance
options
while
also
protecting
the
public
health
with
an
ample
margin
of
safety.

However,
we
agree
that
the
protective
measures
inherent
in
the
look­
up
tables
do
not
necessarily
justify
their
use
in
all
cases.
We
developed
the
look
up
tables
by
running
the
SCREEN3
atmospheric
dispersion
model
with
worst­
case
meteorology
defaults,
an
assumption
of
flat
terrain,
an
assumption
that
building
downwash
effects
are
not
present,

and
an
assumption
that
the
plume
does
not
encounter
a
raincap
or
other
obstruction.
As
several
commenters
identified,
we
recognize
that
site­
specific
factors
not
accounted
for
in
the
SCREEN3
dispersion
modeling,
such
as
building
downwash,
the
presence
of
rain
caps,

and
complex
terrain,
could
make
the
use
of
the
tables
inappropriate
for
some
sources.

Therefore,
we
agree
with
limiting
the
use
of
the
look­
up
tables
to
those
situations
where
the
tables
can
conservatively
represent
actual
site
conditions.
In
order
to
prevent
the
misuse
of
look­
up
tables,
we
are
adding
language
in
section
6
of
appendix
A
to
the
final
rule
to
clarify
that,
although
the
lookup
tables
are
presumed
to
be
applicable
in
each
case,
permit
agencies
have
the
authority
to
determine
on
a
site­
specific
basis,
that
look­
up
tables
may
not
be
used
if
unique
site­
specific
factors,
for
which
the
look­
up
tables
do
not
account,

make
their
use
inappropriate.
In
such
situations,
a
source
would
have
to
demonstrate
eligibility
using
a
site­
specific
risk
assessment
that
does
account
for
these
unique
factors.
If
a
source
is
unable
to
make
this
demonstration
(
e.
g.
if
a
permitting
authority
ultimately
finds
the
eligibility
demonstration
deficient
on
technical
grounds),
the
source
must
then
comply
with
the
technology­
based
standards
in
the
NESHAP.

5.2
Stack
Height
Comment:
Four
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0673,
OAR­

2002­
0058­
0678,
OAR­
2002­
0058­
0682)
agreed
with
the
use
of
the
average
stack
height
parameter.
One
commenter
(
OAR­
2002­
0058­
0673)
stated
that
stack
heights
of
multiple
solid
fuel
units
at
the
same
facility
are
generally
similar,
while
three
commenters
(
OAR­
2002­
0058­

0663,
OAR­
2002­
0058­
0678,
OAR­
2002­
0058­
0682)
suggested
that
this
metric
provides
for
another
level
of
conservatism
in
the
look­
up
table.
One
commenter
(
OAR­
2002­
0058­
0663)

provided
an
example
of
eight
typical
pulp
and
paper
facilities
with
multiple
emission
units
to
show
18
how
this
average
parameter
provides
for
another
layer
of
protection
into
the
risk
analysis.
The
commenter
concluded
that
given
that
the
solid
fuels
are
the
major
sources
of
both
HCl
and
Mn,

and
the
stack
heights
of
oil
and
gas
units
tend
to
be
shorter
than
solid
fuel
units,
an
average
of
all
stack
heights
will
result
in
a
lower
acceptable
emission
rate
in
the
look­
up
tables
than
if
the
height
of
a
unique
solid­
fuel
stack
height
was
used
in
the
analysis.

Three
commenters
(
OAR­
2002­
0058­
0666,
OAR­
2002­
0058­
0669,
OAR­
2002­
0058­

0694)
suggested
alternatives
to
the
average
stack
height
metric.
One
commenter
(
OAR­
2002­

0058­
0694)
proposed
an
alternate
method
of
four
stack
height
ranges
which
is
currently
used
in
the
state's
hazardous
air
pollutant
rule.
The
commenter
suggested
that
these
ranges
are
organized
to
assure
that
the
combined
impact
of
a
source
with
multiple
stack
heights
in
all
four
ranges
would
not
exceed
the
ambient
standards
or
risk.
Two
commenters
(
OAR­
2002­
0058­
0666,

OAR­
2002­
0058­
0669)
requested
EPA
to
consider
weighted
average
stack
heights
and
cited
the
use
of
a
weighted
stack
height
metric
in
the
plywood
NESHAP.
The
commenters
suggested
the
weighted
average
stack
height
more
accurately
portrays
the
potential
risk
than
the
average
stack
height
metric.

Three
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684,
OAR­
2002­
0058­

0694)
suggested
limiting
the
use
of
the
look­
up
tables
to
facilities
with
similar
stack
heights
to
those
assumed
in
the
model.
One
commenter
(
OAR­
2002­
0058­
0694)
added
that
if
the
stack
heights
are
not
similar,
a
more
refined
analysis
should
be
required.

One
commenter
(
OAR­
2002­
0058­
0693
(
see
also
comments
incorporated
by
reference
in
the
original
Petition
for
Reconsideration
in
docket
item
OAR­
2002­
0058­
0657))
disagreed
with
the
use
of
the
average
stack
height,
contending
that
this
approach
understates
risk
and
that
EPA
lacked
a
justification
and
documentation
on
how
the
EPA
chose
this
metric.
According
to
this
commenter,
risk
is
understated
when
a
calculation
averages
the
shortest,
most­
highly
polluting
stack
located
closest
to
neighboring
populations
with
another
emission
point
that
is
taller,
cleaner,

and
farther
away.
The
commenter
also
contended
that
there
is
no
documentation
of
the
analysis
or
data
at
any
step
of
this
rulemaking,
including
this
reconsideration,
which
supports
the
development
of
the
average
stack
height
metric
that
would
enable
a
member
of
the
public
to
evaluate
EPA's
methodology.
The
commenter
provided
an
analysis
of
average
stack
heights
of
municipal
utilities
and
wood­
fired
boilers
for
two
documents
identified
in
the
docket.
The
19
commenter
concluded
that
neither
of
these
documents
justifies
the
use
of
average
stack
heights
or
support
the
agency
claim
that
stack
heights
are
generally
similar.

Response:
We
agree
that
the
average
stack
height
is
not
the
best
metric
for
characterizing
risk,
and
that
a
more
precise
approach
is
the
weighted
stack
height
metric
proposed
in
the
Plywood
NESHAP
amendments.
We
are
changing
the
stack
height
metric
in
the
boilers
and
process
heaters
rule
by
adding
two
equations
to
appendix
A,
similar
to
the
approach
used
for
Equations
3
and
4
listed
in
appendix
B
of
40
CFR
Part
63
Subpart
DDDD.
Equations
1
and
2
of
appendix
A
of
40
CFR
Part
63
Subpart
DDDDD
will
also
be
modified
to
harmonize
the
existing
calculations
of
appendix
A
with
the
new
weighted
stack
height
metric.
The
complete
rationale
for
selecting
the
weighted
stack
height
metric
can
be
found
in
the
proposed
amendments
to
the
Plywood
NESHAP
at
70
FR
44021.

The
weighted
stack
height
metric
is
more
accurate
and
addresses
commenters'
concerns
about
under
predicting
risk
in
certain
situations.
There
are
situations
where
the
average
stack
height
is
health
protective,
(
e.
g.,
when
most
emissions
are
from
the
tallest
stacks)
and
situations
where
the
average
stack
height
metric
is
not
health
protective,
(
e.
g.,
when
most
emissions
are
from
the
shortest
stacks).
The
toxicity­
and
emissions­
weighted
stack
height,

which
we
are
incorporating
into
appendix
A,
is
more
health
protective
when
most
emissions
are
from
the
shortest
stacks.
The
new
equations
factor
in
the
amount
of
emissions
and
the
toxicity
of
the
HAP
emitted
from
each
stack
and
weight
the
result
toward
the
height
of
the
stacks
with
greater
toxicity­
weighted
emissions.
This
addresses
concerns
about
averaging
the
height
of
a
short,
highly­
emitting
stack
with
higher
but
lower­
emitting
stack.
Further,
using
this
more
precise
method
does
not
undercut
our
reliance
on
other
health­
protective
assumptions
in
the
look­
up
table
analysis
when
most
of
the
emissions
come
from
taller
stacks.
As
discussed
below,
the
look­
up
table
analysis
will
continue
to
require
an
assumption
that
all
emissions
occur
at
the
location
of
the
stack
closest
to
the
property
line
of
an
affected
source.
This
health­
protective
assumption
avoids
under
predicting
risk
in
situations
where
the
highest­
emitting
stack
is
located
closest
to
the
property
line.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0678,
OAR­
2002­
0058­
0682)
contested
that
the
average
stack
height
does
not
consider
the
significant
plume
rise
from
hot
plumes
and
thus
over
estimates
ambient
concentrations.
The
commenter
added
that
plume
rise
and
ambient
20
concentrations
are
directly
proportional
and
this
plume
rise
greatly
reduces
ground
level
ambient
concentrations.

Response:
We
disagree
with
the
commenter's
assertion
that
our
look­
up
tables
do
not
correctly
account
for
plume
rise
from
hot
plumes.
In
the
modeling
used
to
develop
the
lookup
tables,
we
assumed
a
stack
gas
temperature
that
was
typical
for
the
industry
according
to
our
available
data.
Alternatively,
sources
can
conduct
a
site­
specific
risk
assessment
if
they
choose
in
order
to
better
account
for
plume
rise
at
a
specific
source.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684)
stated
that
EPA
did
not
account
for
the
height
of
a
building
for
stacks
that
are
attached
to
a
building
structure.
The
commenters
added
that
the
building
height
has
large
impacts
on
facilities
with
shorter
stack
heights
and
presents
a
comparison
of
the
lookup
table
values
found
in
Table
2
of
appendix
A
to
support
this
claim.

Response:
It
is
incorrect
to
say
that
our
lookup
tables
do
not
account
for
building
height.
The
definition
of
stack
height
is
the
height
above
ground
and,
therefore,
this
approach
correctly
accounts
for
the
height
of
stacks
that
are
attached
to
a
building
structure.

5.3
Distance
to
Property
Comment:
Several
commenters
(
OAR­
2002­
0058­
0678,
OAR­
2002­
0058­
0666,
OAR­

2002­
0058­
0669,
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­

2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­
2002­
0058­
0698)
suggested
that
the
use
of
the
minimum
distance
to
property
boundary
metric
is
overly
conservative.
Two
commenters
(
OAR­

2002­
0058­
0666,
OAR­
2002­
0058­
0669)
requested
EPA
allow
a
weighted­
average
for
the
distance
to
property
boundary
when
there
are
multiple
emission
units.
These
two
commenters
argued
this
metric
would
portray
more
accurate
estimates
of
the
potential
risk
from
facilities.

One
commenter
(
OAR­
2002­
0058­
0684)
requested
that
the
modeling
protocol
for
HAP
should
be
consistent
with
the
modeling
protocols
for
criteria
pollutants
under
the
PSD
protocols
found
at
40
CFR
Part
51
Appendix
W,
with
respect
to
using
the
point
of
maximum
impact
instead
of
the
minimum
distance
to
property
boundary.
The
commenter
expressed
concern
that
the
current
use
of
minimum
property
distance
may
not
be
the
point
of
maximum
impact.
21
Response:
We
disagree
with
changing
the
minimum
distance
to
property
boundary.

We
recognize
that
the
minimum
distance
to
property
boundary
may
overestimate
the
ambient
concentration
and
exposure;
however,
we
emphasize
the
health­
protective
nature
of
the
lookup
tables
and
do
not
deem
it
appropriate
to
change
this
metric
towards
one
that
would
be
uniformly
less
health­
protective.

It
is
incorrect
to
assert
that,
when
performing
a
lookup
table
analysis,
the
minimum
distance
to
the
property
line
boundary
may
not
be
the
point
of
maximum
impact.

For
the
lookup
tables,
we
developed
the
allowable
emission
rate
for
each
property
boundary
distance
from
the
maximum
modeled
HAP
concentrations
beyond
that
property
boundary
distance.
As
a
result,
a
look­
up
table
analysis
necessarily
considers
the
point
of
maximum
pollutant
impact
outside
the
source's
property
boundary.
This
is
consistent
with
appendix
W
of
40
CFR
part
51.
22
Chapter
6
Site­
Specific
Assessment
Comment:
Several
commenters
(
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0672,
OAR­

2002­
0058­
0681,
OAR­
2002­
0058­
0678,
OAR­
2002­
0058­
0673,
OAR­
2002­
0058­
0665)

supported
the
level
of
guidance
provided
by
EPA
for
the
site­
specific
assessment
and
believed
the
discretion
to
use
any
"
scientifically­
accepted,
peer­
reviewed
risk
assessment
methodology."

These
commenters
also
supported
the
reference
in
the
final
rule
to
the
Air
Toxics
Risk
Assessment
Reference
Library
(
ATRA)
guidance
document.
One
commenter
(
OAR­
2002­
0058­

0688)
added
that
this
approach
allows
facilities
to
incorporate
evolving
risk
assessment
techniques
and
thought
this
guidance
citation
to
the
Air
Toxics
Risk
Assessment
Reference
Library
was
more
appropriate
than
additional
details
within
the
regulation
itself,
due
to
the
ever­
changing
nature
of
risk
assessment
methodologies.
The
commenter
added
that
providing
assessment
details
in
the
regulatory
language
would
require
constant
updates
to
the
regulations
as
methodologies
evolve.

One
commenter
(
OAR­
2002­
0058­
0673)
stated
this
level
of
guidance
allows
for
flexibility
for
the
affected
sources
and
supported
the
method
as
long
as
it
is
scientifically
defensible,
transparent,

and
peer­
reviewed.
One
commenter
(
OAR­
2002­
0058­
0665)
added
that
many
facilities
have
already
invested
time
in
initiating
or
completing
site­
specific
risk
assessments
in
accordance
with
the
procedures
set
forth
in
appendix
A.
The
commenter
stated
that
the
thresholds
for
site­
specific
assessments
are
derived
directly
from
section
112(
f)
and
the
methodology
of
these
assessments
is
identical
to
those
used
during
the
residual
risk
evaluations.
Two
commenters
(
OAR­
2002­
0058­

0672,
OAR­
2002­
0058­
0681)
stated
contrary
to
other
comments,
substantial
guidance
for
conducting
site­
specific
assessments
exists
and
that
this
guidance
is
expressly
cited
within
the
MACT
rule.
The
commenters
stated
that
Chapters
8
and
9
of
this
ATRA
guideline
contain
a
list
of
specific
air
dispersion
models
that
are
supported
and
specifies
circumstances
where
the
models
are
appropriate.
Additionally,
the
commenters
suggested
the
user
manuals
for
air
quality
models
supported
by
EPA
provide
additional
detailed
guidance.
These
commenters
disagreed
with
23
incorporating
a
set
of
simple,
prescriptive
rules
for
conducting
site­
specific
risk
analyses
into
the
rule
citing
the
complexity
involved
in
the
process
of
site­
specific
risk
assessment.
Further,
the
commenters
stated
the
variability
in
the
affected
sources
limits
the
Agency's
ability
to
establish
a
set
of
rules
that
would
be
appropriate
for
all
facilities.
The
commenters
added
that
a
specific
set
of
rules
impedes
the
mission
to
provide
scientifically
accurate
risk
assessments.

One
commenter
(
OAR­
2002­
0058­
0670)
requested
to
amend
the
NESHAP
to
specify
that
facilities
that
do
not
use
the
EPA's
Air
Toxics
Risk
Assessment
Reference
Library
obtain
regulatory
agency
approval
prior
to
using
other
scientifically
accepted
peer
reviewed
methodology.
This
commenter
suggested
this
amendment
will
provide
clear
guidance
for
facilities
on
the
type
of
methodology
and
prevent
unnecessary
disapprovals
of
the
final
risk
determinations
by
the
permitting
authority.

Four
commenters
(
OAR­
2002­
0058­
0694,
OAR­
2002­
0058­
0693,
OAR­
2002­
0058­

0683,
OAR­
2002­
0058­
0684)
disagreed
with
the
level
of
guidance
EPA
provided
for
conducting
a
site­
specific
assessment.
Three
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684,

OAR­
2002­
0058­
0693)
added
that
there
is
a
lack
of
basic
methods
or
required
parameters,
such
as
the
years
of
exposure
to
an
individual
which
might
lead
to
basing
a
risk
assessment
on
a
oneyear
exposure
instead
of
the
traditional
lifetime
exposure.
Two
commenters
(
OAR­
2002­
0058­

0683,
OAR­
2002­
0058­
0684)
contended
that
without
specific
guidance,
the
site­
specific
assessment
provides
a
meaningless
measure
of
impact.
One
commenter
(
OAR­
2002­
0058­
0693)

stated
that
while
EPA
has
provided
some
guidance
on
performing
site­
specific
assessments,
EPA
has
a
responsibility
to
develop
constraints
on
the
sources'
discretion.
The
commenter
contended
that
the
lack
of
constraint
included
in
this
rule
does
not
provide
specific,
knowable,
replicable
and
enforceable
legal
standards
necessary
to
govern
and
enforce
this
standard.
The
commenter
added
that
the
loose
guidance
provided
for
in
selecting
a
site­
specific
assessments
can
be
interpreted
as
unlimited
discretion
for
the
affected
source,
and
thus
prevent
any
future
efforts
for
administrative
challenge.
Further,
the
commenter
stated
that
this
lack
of
constraint
provides
the
source
with
the
task
of
writing
its
own
rules
and
determining
whether
or
not
a
source
will
be
required
to
incur
compliance
costs.

Response:
We
believe
that
providing
sources
with
the
discretion
to
use
any
"
scientifically­
accepted,
peer­
reviewed
risk
assessment
methodology"
is
appropriate.

However,
contrary
to
the
assertions
of
some
commenters,
this
discretion
is
not
unlimited.
24
In
section
7(
c)
of
appendix
A,
EPA
has
established
specific
minimum
criteria
for
sitespecific
compliance
demonstrations.
In
order
to
demonstrate
eligibility
for
the
healthbased
compliance
alternative,
the
site­
specific
risk
assessment
conducted
by
the
facility
must
meet
the
following
criteria:
(
1)
estimate
long­
term
inhalation
exposures
through
the
estimation
of
annual
or
multi­
year
average
ambient
concentrations;
(
2)
estimate
the
inhalation
exposure
for
the
individual
most
exposed
to
the
facility's
emissions;
(
3)
use
sitespecific
quality­
assured
data
wherever
possible;
(
4)
use
health­
protective
default
assumptions
wherever
site­
specific
data
are
not
available;
and
(
5)
contain
adequate
documentation
of
the
data
and
methods
used.

Furthermore,
EPA
cited
the
Air
Toxics
Risk
Assessment
(
ATRA)
Reference
Library
to
provide
guidance
to
the
sources
and
state
on
developing
technically
sound
site
specific
risk
assessments.
The
ATRA
Reference
Library
provides
examples
of
how
a
risk
assessment
can
be
conducted.
These
examples
include
instruction
in
basic
risk
assessment
methodology,
in
determining
what
parameters
to
include
in
a
risk
assessment,
and
in
the
constraints
that
should
be
placed
on
those
parameters.
The
documents
within
the
ATRA
Reference
Library
have
been
peer­
reviewed
and
were
developed
according
to
the
principles,
tools
and
methods
outlined
in
the
1999
EPA
Residual
Risk
Report
to
Congress.

However,
the
guidance
in
the
ATRA
Reference
Library
may
not
be
appropriate
for
all
sources.
For
that
reason
sources
may
consider
alternative
analytical
tools
as
long
as
these
alternatives
are
scientifically
defensible,
peer­
reviewed
and
transparent.

Finally,
the
discretion
of
each
source
is
not
unlimited
because
permitting
agencies
have
the
authority
to
review
each
site­
specific
eligibility
demonstration
to
determine
if
it
meets
the
applicable
requirements
in
section
7(
c)
of
appendix
A
and
if
the
methodology,
as
applied
in
the
demonstration
of
eligibility,
is
technically
sound
and
appropriate.
After
reviewing
a
source's
compliance
demonstration,
the
permitting
authority
makes
the
final
determination
of
whether
site­
specific
assessments
are
completely
and
correctly
submitted.

These
authorities
may
reject
site­
specific
assessments
if
they
do
not
meet
the
requirements
of
section
7
of
appendix
A
or
if
they
contain
technical
flaws
with
respect
to
the
risk
assessment
methodology.
Thus,
it
may
be
advisable
for
sources
to
seek
prior
approval
when
using
a
methodology
that
deviates
from
the
approach
in
the
Air
Toxics
Risk
25
Assessment
Reference
Library.
However,
we
do
not
feel
that
it
is
necessary
to
require
this
prior
approval.

Comment:
One
commenter
(
OAR­
2002­
0058­
0694)
requested
that
facilities
choosing
to
apply
for
the
site­
specific
assessment
be
required
to
perform
a
residual
risk
analysis
as
part
of
their
submission
of
eligibility;
the
commenter
requested
that
this
risk
analysis
be
submitted
to
the
US
EPA
for
review.

Response:
At
this
time,
we
do
not
consider
a
residual
risk
analysis
to
be
warranted
under
section
112(
d).
Under
the
CAA,
residual
risk
evaluations
are
required
to
be
conducted
eight
years
after
publication
of
the
112(
d)
standards.
26
Chapter
7
Background
Emissions/
Co­
located
Emissions
Comment:
Multiple
commenters
(
OAR­
2002­
0058­
0666,
OAR­
2002­
0058­
0667,
OAR­

2002­
0058­
0687,
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0680,
OAR­

2002­
0058­
0682,
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0669,
OAR­
2002­
0058­
0675,
OAR­

2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­

2002­
0058­
0698,
OAR­
2002­
0058­
0669)
disagreed
with
EPA's
decision
not
to
include
background
or
co­
located
emissions
when
determining
whether
or
not
a
facility
qualifies
for
the
health­
based
compliance
alternative
standards
in
the
final
rule.
Several
commenters
(
OAR­
2002­

0058­
0677,
OAR­
2002­
0058­
0693,
OAR­
2002­
0058­
0694,
OAR­
2002­
0058­
0683,
OAR­
2002­

0058­
0684)
stated
that
when
evaluating
whether
or
not
a
facility
is
eligible
to
comply
with
the
health­
based
compliance
alternatives,
the
background
or
co­
located
emissions
should
be
included
in
the
risk
determination.

Several
of
the
commenters
that
opposed
consideration
of
emissions
from
background
or
co­
located
sources
(
OAR­
2002­
0058­
0687,
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0672,

OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,

OAR­
2002­
0058­
0697,
OAR­
2002­
0058­
0698,
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0671)

argued
that
the
statutory
language
in
sections
112(
d)
does
not
provide
EPA
with
the
legal
authority
to
consider
emissions
from
other
source
categories.
Many
of
these
commenters
also
provided
counter­
examples
of
sections
of
the
CAA
where
the
Congressional
intent
was
focused
on
including
background
or
co­
located
emissions.
Several
commenters
(
OAR­
2002­
0058­
0675,

OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,

OAR­
2002­
0058­
0698)
added
that
background
or
co­
located
emissions
do
not
fall
into
a
source
category
or
subcategory
of
major
sources
listed
for
regulation.
Two
commenters
(
OAR­
2002­

0058­
0663,
OAR­
2002­
0058­
0680)
stated
that
there
is
no
precedent
for
the
consideration
of
background
or
co­
located
emissions
during
the
promulgation
of
the
benzene
NESHAP
or
during
the
litigation
of
the
vinyl
chloride
NESHAP.
27
Three
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0680,
OAR­
2002­
0058­

0688)
cited
a
1990
Senate
Report,
and
concluded
that
the
consideration
of
background
or
colocated
emission
sources
would
be
the
kind
of
lengthy
study
Congress
intended
to
avoid.
Two
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0680)
cited
risk
documents
from
the
Presidential/
Congressional
Commission
on
Risk
Assessment
and
Risk
Management,
and
a
paper
written
by
the
Residual
Risk
Coalition
to
support
their
position
on
excluding
background
and
colocated
emission
sources
when
evaluating
whether
or
not
a
facility
qualifies
for
the
health­
based
alternative
standard
in
appendix
A.

One
commenter
(
OAR­
2002­
0058­
0663)
believed
EPA
has
no
legal
basis
for
reconsidering
the
concept
of
including
background
or
other
sources
in
the
risk
determination,
and
they
cited
that
this
issue
has
been
through
appropriate
notice­
and­
comment
process.

One
commenter
(
OAR­
2002­
0058­
0672)
argued
that
the
public
health
is
most
protected
when
regulations
are
specific
to
a
source
category
and
provided
examples
of
how
the
different
provisions
of
the
CAA
account
for
different
sources
of
HAP.
The
commenter
added
that
the
consideration
of
background
emissions
would
over­
regulate
the
affected
source
category
and
effectively
require
certain
sources
to
compensate
for
other
sources
of
HAP.

Two
of
the
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684)
that
supported
considering
emissions
from
background
and
co­
located
sources
contended
that
the
major
source
status
is
based
on
facility­
wide
emissions
and
limiting
the
risk
analysis
to
certain
sources
within
the
facility
presents
an
unrealistic
view
of
the
facility's
impact.
One
commenter
(
OAR­
2002­

0058­
0693)
added
that
the
EPA
must
meet
its
duty
of
providing
for
an
"
ample
margin
of
safety"

by
evaluating
the
risk
of
background
emissions
now
as
opposed
to
during
the
residual
risk
evaluation.
One
commenter
(
OAR­
2002­
0058­
0677)
stated
that
risk
assessment
should
be
done
in
the
context
of
all
HAP
sources
at
the
facility
and
at
nearby
facilities.
One
of
these
commenters
(
OAR­
2002­
0058­
0694)
disagreed
with
the
health­
based
compliance
alternative
for
metals
because
it
does
not
adjust
for
facility­
wide
emissions.

Three
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684,
OAR­
2002­
0058­

0677)
cited
the
1996
National
Air
Toxics
Assessment
(
NATA)
for
support
of
the
concern
of
high
exposures
to
air
toxics
throughout
the
country
and
stated
a
reduction
in
such
exposures
will
require
a
general
reduction
across
all
sources.
These
commenters
expressed
concern
that
28
excluding
background
or
co­
located
emissions
ignore
cumulative
risk
and
do
not
protect
the
public
health.

One
commenter
(
OAR­
2002­
0058­
0694)
contended
that
the
tiered
risk
approach
used
at
the
state
level
correctly
considers
background
emissions,
in
contrast
to
the
exclusion
of
these
background
emissions
in
the
final
NESHAP.
The
commenter
added
that
by
excluding
these
background
sources,
the
final
NESHAP
rule
identifies
low­
risk
subcategories
based
on
an
unrealistic
view
of
the
facility
impact.
The
commenter
also
concluded
that
the
refined
site­
specific
risk
screening
provides
no
real
measure
of
health
impact
without
including
background
or
colocated
emission
sources.

Response:
Based
on
the
arguments
made
by
several
commenters
and
our
review
of
the
Clean
Air
Act,
it
is
permissible
under
section
112(
d)
of
the
Act
to
limit
our
analysis
to
establishing
emissions
limitations
for
only
those
sources
in
the
individual
source
categories
subject
to
this
action.
Therefore,
in
developing
emissions
limitations
under
112(
d),
we
believe
emissions
from
sources
outside
of
this
source
category
need
not
be
considered
to
determine
eligibility
for
the
health
based
compliance
alternatives
for
industrial,

commercial,
and
institutional
(
ICI)
boilers
and
process
heaters.
Although
we
may
combine
several
source
categories
into
one
NESHAP
as
we
did
in
this
action,
we
do
not
construe
the
Act
to
require
that
we
regulate
the
emissions
from
all
other
source
categories
through
an
individual
112(
d)
rule
for
particular
source
categories.

The
focus
of
section
112(
d)
is
on
establishing
emissions
standards
for
individual
source
categories.
Section
112(
d)(
1)
indicates
that
the
administrator
is
to
"
promulgate
regulations
establishing
emissions
standards
for
each
category
or
subcategory
of
major
sources
and
area
source
of
hazardous
air
pollutants
listed
for
regulation
pursuant
to
subsection
(
c)
of
this
section
in
accordance
with
the
scheduled
provided
in
subjections
(
c)

and
(
e)
of
this
section."
The
health­
based
compliance
alternatives
are
included
among
the
emissions
standards
we
have
established
for
ICI
boilers
and
process
heaters
under
section
112(
d).
Section
112(
d)(
4)
states
that
"
the
Administrator
may
consider
such
threshold
level,

with
an
ample
margin
of
safety,
when
establishing
emission
standards
under
this
subsection."
The
subsection
described
in
this
provision
of
the
statute
is
subsection
112(
d).

Since
the
"
ample
margin
of
safety"
provision
is
also
contained
within
section
112(
d),
we
do
not
interpret
this
part
of
the
Act
to
require
that
we
consider
emissions
from
other
source
29
categories
in
establishing
a
health­
based
alternative
under
section
112(
d)(
4)
for
one
category
of
sources.
Based
on
the
overall
focus
of
section
112(
d)
on
sources
in
specific
categories,
we
believe
the
"
ample
margin
of
safety"
criteria
should
be
applied
to
the
emissions
of
threshold
pollutants
from
the
individual
source
category
subject
to
each
NESHAP.

We
agree
with
several
commenters
that
the
legislative
history
supports
this
view
that
Congress
intended
for
EPA
to
focus
only
on
the
emissions
from
sources
within
a
particular
category
when
establishing
health­
based
standards
for
a
particular
source
category
under
section
112(
d)(
4).
The
Senate
Report
stated
that
the
following:

The
Administrator
is
authorized
by
section
112(
d)(
4)
to
use
the
no
observable
effects
or
NOEL
(
again
with
an
ample
margin
of
safety)
as
the
emissions
limitation
in
lieu
of
more
stringent
"
best
technology"
requirements.
Following
this
scenario,
only
those
sources
in
the
category
which
present
a
risk
to
public
health
(
those
emitting
in
amounts
greater
than
the
safety
threshold)
would
be
required
to
install
controls,
even
though
the
general
policy
is
"
maximum
achievable
technology"
everywhere.
1
This
statement
suggests
an
intent
for
EPA
to
address
only
whether
"
sources
in
the
category"
present
a
risk
to
public
health
when
EPA
in
determining
whether
individual
sources
in
the
category
should
have
to
comply
with
a
technology­
based
emissions
limitation
or
may
avoid
installation
of
controls
by
demonstrating
that
the
emissions
from
a
source
do
not
present
risks
greater
than
an
established
health
threshold.

Thus
it
is
permissible
to
conclude
that
the
facility­
wide
impact
is
not
the
focus
of
the
analysis
in
the
development
of
a
section
112(
d)
rule.
Under
our
interpretation,
the
appropriate
analysis
under
the
Act
is
whether
the
emissions
of
sources
in
the
applicable
category
(
without
consideration
of
emissions
from
sources
in
other
categories)
are
below
the
health
threshold.
Under
the
eligibility
demonstration
methodology
set
forth
in
Appendix
A
of
subpart
DDDDD,
a
source
must
demonstrate
eligibility
based
on
the
emissions
of
all
emissions
units
in
the
ICI
boilers
and
process
heaters
source
category.

Because
all
emissions
units
in
the
category
are
covered,
any
background
emissions
or
1
S.
Rep.
No.
228,
101st
Cong.,
1st.
Session
175­
6
(
1990).
30
emissions
from
other
sources
at
a
particular
location
would
have
to
be
emissions
from
sources
in
other
categories
or
emissions
that
occur
naturally.

We
do
not
read
section
112(
d)
to
require
us
to
use
emissions
from
sources
outside
the
category
to
establish
health­
based
alternatives
for
sources
in
the
ICI
boilers
category.

Likewise,
we
do
not
believe
eligibility
for
health­
based
alternatives
should
be
determined
by
using
a
sum
of
emissions
from
all
source
categories
or
by
lowering
the
health
threshold
for
emissions
from
one
source
category
to
account
for
emissions
from
other
source
categories.
We
believe
we
should
concentrate
on
only
the
emissions
from
each
source
category
to
establish
health­
based
emissions
limitations
for
that
category
and
in
determining
whether
sources
in
that
category
are
eligible
to
comply
with
health­
based
emissions
limitations
or
must
meet
a
technology­
based
emissions
limitation.

Although
a
particular
facility
may
be
identified
as
a
major
source
of
HAPs
for
purposes
of
section
112
on
the
basis
of
emissions
from
affected
sources
in
multiple
source
categories,
this
does
not
require
that
we
establish
eligibility
for
a
health­
based
emissions
limitation
in
a
particular
source
category
based
on
emissions
from
co­
located
sources
outside
the
category.
Emissions
units
in
other
source
categories
located
at
the
same
major
source
site
remain
subject
to
the
technology­
based
emissions
limitations
contained
in
other
NESHAPs
promulgated
under
section
112(
d).
The
sources
covered
by
these
NESHAPs
are
not
eligible
to
comply
with
the
health­
based
alternatives
in
the
ICI
boilers
and
process
heaters
NESHAP.

Under
either
scenario,
each
source
is
subject
to
regulatory
requirements
(
whether
health
or
technology­
based)
that
address
the
health
risks
posed
by
emissions
from
that
facility.
The
health­
based
compliance
alternatives
in
the
40
CFR
Part
63,
subpart
DDDDD
are
only
available
for
HCl
and
Mn,
and
only
if
emissions
of
these
HAP
meet
the
healthbased
criteria
defined
in
appendix
A.
Affected
sources
that
can
comply
with
the
healthbased
alternatives
in
appendix
A
are
still
subject
to
other
emissions
standards
under
the
NESHAP.

With
respect
to
the
concerns
about
cumulative
risk,
emission
standards
under
section
112(
d)
are
only
one
aspect
of
a
broader
national
air
toxics
control
program.
Under
the
residual
risk
program,
we
may
consider,
as
appropriate,
risks
from
other
source
categories
and
risks
from
the
total
emissions
from
a
particular
location.
This
approach
was
31
reiterated
in
the
recently
finalized
Coke
Oven
Residual
Risk
rule
where
we
said
we
will
only
consider
emissions
from
the
regulated
source
category
when
determining
"
acceptable
risk"
during
the
first
step
of
the
residual
risk
analysis.
However,
during
the
second
step,

where
we
determine
the
ample
margin
of
safety
considering
costs
and
technical
feasibility
(
see
70
FR
19997­
19998),
we
may
consider
co­
located
sources
and
background
levels
where
appropriate.

Comment:
Three
commenters
(
OAR­
2002­
0058­
0682,
OAR­
2002­
0058­
0669,
OAR­

2002­
0058­
0678)
agreed
with
the
Agency
suggestion
to
revisit
the
consideration
of
background
emission
during
future
residual
risk
evaluations.
However,
one
commenter
(
OAR­
2002­
0058­

0688)
disagreed
with
the
suggestion
to
revisit
facility­
wide
residual
risk
determinations
in
future
residual
risk
rules
and
stated
that
the
EPA
does
not
have
the
authority
to
mandate
facility­
wide
residual
risk
determinations.
The
commenter
provided
an
attachment
of
the
Coke
Oven
Residual
Risk
Rule
to
support
their
position.
Several
commenters
stated
an
intention
to
address
this
issue
in
subsequent
residual
risk
rulemakings
if
EPA
proposes
to
revisit
facility­
wide
emissions
at
this
stage.

Four
commenters
(
OAR­
2002­
0058­
0677,
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­

0694,
OAR­
2002­
0058­
0684)
expressed
concern
on
considering
co­
located
emissions
only
during
the
residual
risk
analysis.
One
commenter
(
OAR­
2002­
0058­
0694)
stated
that
deferring
the
risk
screening
is
contrary
to
the
intent
of
the
Clean
Air
Act.
Three
commenters
(
OAR­
2002­
0058­

0683,
OAR­
2002­
0058­
0684,
OAR­
2002­
0058­
0677)
were
not
satisfied
with
the
residual
risk
evaluations
performed
to
date.
Two
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­

0684)
specifically
cited
that
background
concentrations
for
benzene
or
any
other
HAP
were
not
incorporated
into
the
Coke
Oven
Residual
Risk
report.
One
commenter
(
OAR­
2002­
0058­
0693)

added
that
the
EPA
must
meet
its
duty
of
providing
for
an
"
ample
margin
of
safety"
by
evaluating
the
risk
of
background
emissions
now
as
opposed
to
during
the
residual
risk
evaluation.
The
commenter
added
that
in
deferring
the
consideration
of
these
background
emission
sources
until
the
residual
risk
evaluation,
the
agency
is
acting
arbitrary,
capricious,
and
otherwise
not
in
accordance
with
law.

Response:
To
the
extent
necessary,
we
believe
the
appropriate
stage
for
considering
total
facility
risk
from
air
toxics
emissions
is
at
the
residual
rulemaking
risk
stage
under
section
112(
f)
of
the
Act.
As
noted
above,
we
do
not
construe
the
requirement
in
section
32
112(
d)(
4)
to
"
consider
such
threshold,
with
an
ample
margin
of
safety,
when
establishing
emission
standards"
under
subsection
(
d)
to
require
assessment
of
the
cumulative
risk
at
a
given
location
due
to
the
emissions
from
all
source
categories
at
this
stage
of
NESHAP
development.
However,
as
stated
in
our
recent
residual
risk
rule
for
coke
ovens,
we
do
not
agree
that
section
112(
f)
entirely
precludes
EPA
from
considering
emissions
other
than
those
from
the
relevant
source
category
during
a
residual
risk
rulemaking
analysis
for
an
individual
source
category
(
see
70
Fed.
Reg.
19992,
19998
(
Apr.
15,
2005)).
Section
112(
f)

directs
EPA
to
consider
whether
promulgation
of
additional
standards
"
is
required
to
provide
an
ample
margin
of
safety
to
protect
public
health."

Although
the
phrase
"
ample
margin
of
safety"
is
used
in
both
sections
112(
d)(
4)
and
112(
f),
the
context
surrounding
the
phrase
is
different
in
each
section.
The
context
of
subsection
112(
d)
focuses
on
each
individual
source
category
for
which
we
are
promulgating
a
NESHAP
under
subsection
(
d).
Although
we
agree
that
the
first
stage
of
our
112(
f)
analysis
should
focus
on
the
risks
from
each
individual
source
category,
we
believe
we
may
consider
cumulative
risks
to
some
extent
in
implementing
the
"
ample
margin
of
safety"
requirement
in
the
context
of
subsection
(
f)
and
in
evaluating
"
other
relevant
factors"
under
this
subsection
(
see
70
Fed.
Reg.
at
19998).
As
a
result,
we
believe
the
appropriate
stage
for
any
consideration
of
cumulative
facility
risks
is
this
second
part
of
the
residual
risk
analysis
rather
than
in
the
development
and
implementation
of
a
healthbased
alternative
under
section
112(
d)(
4)
of
the
Act.

We
do
not
construe
section
112(
d)(
4)
of
the
Act
to
accelerate
the
residual
risk
analysis
under
section
112(
f)
when
we
invoke
section
112(
d)(
4)
to
establish
a
health­
based
standard
during
the
first
stage
or
rulemaking
under
section
112(
d).
In
this
action,
we
are
implementing
section
112(
d)
of
the
Act
and
are
not
writing
a
regulation
based
on
section
112(
f).
Section
112(
d)(
4)
does
not
call
for
a
residual
risk
analysis
for
all
sources
in
the
category.
Rather,
this
provision
allows
EPA
to
consider
the
existence
of
health
thresholds
(
with
an
adequate
margin
of
safety)
for
particular
pollutants
at
the
first
stage
of
the
NESHAP
promulgation
process.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684)
felt
it
was
unclear
how
the
health­
based
compliance
alternatives
will
affect
section
112(
f)
residual
risk
33
evaluations
for
HCl
and
Mn,
and
asked
if
these
two
threshold
pollutants
will
be
exempted
from
residual
risk
assessments.

Response:
HCl
and
Mn
will
not
be
exempted
in
future
112(
f)
analyses.
Rather,

exposure
to
these
two
pollutants
will
be
assessed
along
with
exposure
to
other
HAP
emitted
from
the
source
category.

Comment:
Several
commenters(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0682,
OAR­

2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­

2002­
0058­
0697,
OAR­
2002­
0058­
0698)
believed
that
it
was
not
necessary
to
account
for
background
or
emissions
from
other
sources
because
the
multiple
levels
of
protection
in
the
existing
methodologies
for
both
the
exposure
and
dose/
response
assessments
provide
for
the
protection
of
public
health
with
an
ample
margin
of
safety.
One
commenter
(
OAR­
2002­
0058­

0663)
provided
specific
levels
of
protections
including:
the
RfCs
are
stated
to
be
orders
of
magnitude
below
any
observable
adverse
effect
in
scientific
studies,
additionally
the
exposure
assumption
is
based
on
a
constant
24
hour,
365
day
exposure
for
70
years.
In
addition,
the
commenter
stated
that
the
HI
value
of
1.0
chosen
in
the
final
rule
is
one
order
of
magnitude
less
than
the
recommendations
provided
in
the
Presidential/
Congressional
Commission
on
Risk
Assessment
for
non­
cancer
hazard
index
values.
These
commenters
concluded
it
is
unjustified
to
provide
additional
levels
of
protection
through
the
assessment
of
background
or
co­
located
emissions.
One
commenter
(
OAR­
2002­
0058­
0682)
contended
that
a
HI
value
of
0.2
is
an
arbitrary
method
of
accounting
for
background
emissions
and
suggested
that
background
emissions
are
often
near
zero
for
HAP.

One
commenter
(
OAR­
2002­
0058­
0693)
contended
that
the
agency
assertion
of
the
conservatism
inherent
in
the
RfC
values
does
not
justify
the
exclusion
of
background
pollution
and
co­
located
sources,
which
if
included
in
the
calculations,
would
exceed
the
RfC
values.

Response:
We
indicated
in
our
notice
of
proposed
rulemaking
that,
to
the
extent
we
determined
we
should
address
background
concentrations
and
emissions
from
colocated
source
to
determine
eligibility
for
a
health­
based
alternative,
one
option
would
be
to
utilize
an
HI
or
HQ
below
1.0.
In
light,
our
interpretation
that
each
section
112(
d)

rulemaking
should
establish
emissions
limitations
(
including
health­
based
emissions
limitations
when
appropriate)
for
each
category
individually,
we
have
determined
that
it
is
not
necessary
to
consider
potential
background
emissions
or
emissions
from
co­
located
34
sources
or
to
attempt
to
account
for
such
emissions
using
an
HI
or
HQ
of
less
than
1.0
As
a
result,
we
have
not
conducted
any
further
analysis
to
determine
whether
any
specific
HI
or
HQ
level
below
1.0
would
or
would
not
be
appropriate
to
account
for
emissions
from
other
sources.

We
agree
that
the
conservatism
inherent
in
the
RfC
does
not
account
for
background
exposures
and
did
not
intend
to
suggest
this
in
our
June
27,
2005
reconsideration
notice.
However,
for
reasons
provided
in
response
to
other
comments,
we
continue
to
believe
that
the
methods
for
complying
with
the
health­
based
alternatives,
as
outlined
in
appendix
A,
are
appropriately
health
protective
and
that
it
is
not
necessary
to
use
an
HI
or
HQ
less
than
or
greater
than
1.0
to
implement
the
health­
based
alternatives.

We
agree
that
the
conservatism
built
into
the
RfC
helps
meet
our
statutory
obligation
to
consider
established
health
thresholds
"
with
an
ample
margin
of
safety"
when
promulgating
emissions
limitations
for
threshold
pollutants
based
on
section
112(
d)(
4)
of
the
Act.
35
Chapter
8
Health­
Based
Compliance
Alternative
for
Metals
Comment:
One
commenter
(
OAR­
2002­
0058­
0693)
specified
that
EPA
cannot
adopt
risk­
based
exemptions
for
pollutants
for
which
no
health
threshold
has
been
established.
The
commenter
contended,
based
on
documents
in
the
EPA
Integrated
Risk
Information
System
(
IRIS),
that
no
health
threshold
has
been
established
for
Mn.
This
commenter
believes
there
is
evidence
that
manganese
may
have
carcinogenic
effects
and
cites
to
studies
it
believes
are
suggestive
of
carcinogenicity.
In
addition,
this
commenter
takes
issue
with
fact
that
the
RfC
for
manganese
is
based
on
a
LOEAL
rather
than
a
NOEL.
Finally,
this
commenter
argues
EPA's
determination
that
Mn
is
a
threshold
pollutant
is
flawed
because
EPA
focused
on
the
health
effects
of
chronic
exposure
and
ignored
potential
acute
effects.

Two
other
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0695)
specified
that
Mn
has
long
been
recognized
as
a
threshold
pollutant.
Another
commenter
(
OAR­
2002­
0058­

0687)
stated
that
unlike
other
metals
in
the
MACT
list,
Mn
is
not
a
carcinogen,
rather
it
is
a
Class
D
pollutant.

Response:
We
agree
that
health­
based
compliance
alternatives
adopted
under
section
112(
d)(
4)
can
apply
only
to
pollutants
for
which
a
threshold
for
health
effects
has
been
established.
For
the
pollutants
for
which
we
have
elected
to
establish
health­
based
compliance
alternatives
(
manganese
and
HCl),
the
scientific
data
support
a
threshold
approach
to
evaluating
the
potential
for
adverse
health
effects.

For
air
toxics
risk
assessments,
we
identify
pertinent
toxicity
or
dose­
response
values
using
a
default
hierarchy
of
sources
to
assist
us
in
identifying
the
most
scientifically
appropriate
benchmarks.
EPA's
Integrated
Risk
Information
System
(
IRIS)
is
the
preferred
source
in
this
hierarchy.
The
values
in
the
IRIS
database
reflect
EPA
consensus
values
and
their
development
typically
incorporates
extensive
peer
review.
When
adequate
toxicity
information
is
not
available
in
IRIS,
we
consult
other
sources
in
a
default
hierarchy
that
recognizes
the
desirability
of
peer
review
and
consistency
with
EPA
risk
assessment
36
guidelines
to
ensure
that
we
have
consistent
and
scientifically
sound
assessments.
For
substances
lacking
current
IRIS
assessments,
U.
S.
Agency
for
Toxic
Substances
and
Disease
Registry
(
ATSDR)
chronic
MRLs
received
next
preference,
followed
by
California
Environmental
Protection
Agency
(
CalEPA)
chronic
RELs
and
UREs.
Furthermore,
when
there
is
an
IRIS
assessment
but
that
assessment
substantially
lags
the
current
scientific
knowledge,
we
are
committed
to
consider
alternative
credible
and
readily
available
assessments.

Based
on
our
analysis
of
manganese
using
this
approach,
we
believe
the
data
currently
available
show
that
a
health
threshold
has
been
established
for
manganese
and
that
we
are
therefore
authorized
under
section
112(
d)(
4)
to
establish
a
health­
based
alternative
for
this
pollutant.
Under
our
default
hierarchy
approach,
we
first
consulted
IRIS.
IRIS
may
be
found
on
internet
at
<
www.
epa.
gov/
iris>,
but
we
have
added
the
relevant
pages
in
IRIS
to
docket
for
this
rulemaking
action.
As
listed
in
table
4
of
our
notice
of
proposed
rulemaking,
68
Fed.
Reg.
1690
(
Jan.
13,
2003),
IRIS
contains
a
reference
concentration
for
manganese.
However,
IRIS
does
not
contain
a
unit
risk
estimate,
which
addresses
cancer
risk.
EPA's
assessment
in
IRIS
indicates
that
there
is
inadequate
evidence
of
carcinogenicity
for
manganese.
In
addition,
a
cancer
assessment
for
manganese
is
not
available
from
any
of
the
other
sources
in
our
default
hierarchy
or
from
another
scientifically­
credible
source.
Based
on
this
information,
which
we
believe
is
the
best
available
at
the
present
time,
our
judgment
is
that
it
is
only
appropriate
for
EPA
to
evaluate
manganese
with
regard
to
non­
cancer
effects.
In
the
absence
of
specific
scientific
evidence
to
the
contrary,
it
has
been
our
policy
to
classify
non­
carcinogenic
effects
as
threshold
effects.
RfC
development
is
the
default
approach
for
threshold
(
or
nonlinear)

effects.
Thus,
in
the
absence
of
adequate
evidence
that
manganese
is
a
carcinogen
and
based
on
the
presence
of
a
reference
concentration
in
IRIS
for
non­
cancer
effects
of
manganese,
our
best
scientific
judgment
at
this
time
is
that
manganese
is
a
threshold
pollutant.
We
also
used
this
approach
to
reach
a
similar
conclusion
with
respect
to
HCl.

See
Comment­
Response
Document,
pg.
233
(
February
2004).

Regarding
the
LOAEL
issue,
the
methodology
employed
by
EPA
recognizes
that
while
a
NOAEL
is
preferable
to
a
LOAEL
for
use
as
the
point
of
departure
to
which
uncertainty
factors
are
applied
to
derive
an
RfC,
a
LOAEL
may
also
be
used.
U.
S.
37
Environmental
Protection
Agency.
1994.
Methods
for
Derivation
of
Inhalation
Reference
Concentrations
and
Application
of
Inhalation
Dosimetry.
Office
of
Research
and
Development.
EPA/
600/
8­
90/
066F.
IRIS
incorporates
factors
to
account
for
uncertainties
in
the
scientific
database.
The
use
of
a
LOAEL
to
derive
the
RfC
for
manganese
is
one
of
these
uncertainties
and
is
appropriately
addressed
through
the
application
of
uncertainty
factors
as
part
of
the
IRIS
process.

We
disagree
with
the
commenter
that
we
did
not
consider
acute
effects.
We
performed
a
risk
assessment
evaluating
the
potential
acute
effects
of
boiler
emissions,

including
manganese
(
see
docket
item
#
OAR­
2002­
0058­
0608).
We
used
acute
inhalation
reference
values,
taken
from
the
table
on
EPA's
air
toxics
website
(
www.
epa.
gov/
ttn/
atw/
toxsource/
table2.
pdf),
for
all
pollutants
in
this
assessment.
Although
the
commenter
is
correct
that
this
table
does
not
contain
an
AEGL
value
for
manganese
compounds,
the
table
does
contain
an
IDLH/
10
value
of
50
mg/
m3.
This
is
the
acute
doseresponse
value
that
we
used,
as
reflected
in
table
3
(
converted
to
50,000
ug/
m3)
of
the
screening
assessment
memorandum
(
OAR­
2002­
0058­
0608).
Thus,
the
commenter's
assertion
that
the
table
on
the
website
contains
no
acute
dose­
response
value
or
that
EPA
does
not
know
what
that
value
might
be
is
incorrect.
As
described
in
the
screening
assessment
memorandum,
for
HAP
with
more
than
one
acute
dose­
response
value,
the
most
health­
protective
value
was
chosen.
EPA
has
not
prioritized
these
values.
Since
we
only
had
one
value
for
manganese,
we
used
that
value
in
our
acute
assessment.
The
results
indicate
that
HAP
emissions,
including
manganese,
from
the
industrial
boilers
source
category
are
unlikely
to
pose
acute
risks
to
human
health.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684)
disagreed
with
the
use
of
an
HQ
index
for
multi­
pathway
pollutants.

Response:
This
rule
is
relying
on
CAA
§
112(
d)(
4),
which
requires
us
to
evaluate
ecological
and
multimedia
human
exposures
when
determining
the
applicability
of
§

112(
d)(
4).
To
identify
potential
multi­
pathway
and/
or
ecological
concerns,
we
have
developed
a
list
of
HAP
with
the
potential
to
persist
in
the
environment
and
to
bioaccumulate.
This
list
does
not
include
Mn,
HCl,
or
Cl2,
which
are
the
only
HAP
relevant
for
the
health­
based
compliance
alternatives
under
the
final
rule.
Therefore,

facilities
attempting
to
comply
with
the
health­
based
alternatives
are
not
required
to
38
perform
a
multi­
pathway
analysis.
Chapter
4
of
Volume
1
in
the
Air
Toxics
Risk
Assessment
(
ATRA)
Reference
Library
presents
a
complete
list
of
the
multi­
pathway
pollutants.

Comment:
Several
commenters
(
OAR­
2002­
0058­
0671,
OAR­
2002­
0058­
0663,
OAR­

2002­
0058­
0666,
OAR­
2002­
0058­
0669,
OAR­
2002­
0058­
0682,
OAR­
2002­
0058­
0695,
OAR­

2002­
0058­
0687)
agreed
with
the
EPA's
method
for
evaluating
Mn
and
the
basis
of
excluding
Mn
from
the
TSM
emission
limit
for
units
that
comply
with
the
Mn
health­
based
compliance
alternative.
These
commenters
also
stated
this
health­
based
compliance
alternative
protects
the
public
health.

One
commenter
(
OAR­
2002­
0058­
0682)
cited
the
EPA
re­
analysis
of
the
MACT
floor
based
on
7
instead
of
8
metals,
and
concluded
that
because
Mn
was
only
about
5%
of
the
TSM,

the
MACT
floor
remained
the
same.
This
commenter
also
supported
the
separate
risk
analysis
for
Mn.

One
commenter
(
OAR­
2002­
0058­
0687)
stated
that
without
this
change
to
base
the
TSM
limit
on
7
rather
than
8
metals,
wood
fuel
boilers
would
be
required
to
install
control
technology
to
control
Mn
exclusively,
or
switch
to
a
nonrenewable
fuel.
The
commenter
added
that
the
controls
would
exceed
one
million
per
ton
of
Mn
removed.
The
commenter
added
that
wood
fuel
is
recognized
as
a
clean,
renewable
resource
and
that
of
the
metals
in
the
MACT
list,
AP­
42
factors
represent
Mn
to
be
91.8%
of
the
metallic
HAP
in
wood
fuels.
The
commenter
contended
that
unlike
other
metals
in
the
MACT
list,
Mn
is
not
a
carcinogen,
rather
it
is
a
Class
D
pollutant.

The
commenter
concluded
that
Mn
impacts
human
health
only
when
humans
are
`
chronically
exposed
at
high
levels'
and
EPA
would
be
acting
in
error
to
require
expensive
controls
to
meet
the
NESHAP
standards
when
a
risk
to
human
health
is
not
posed
by
these
clean
wood
burning
units.
The
commenter
referenced
a
1992
EPA
Manganese
Hazard
Summary
and
69
Fed.
Register
at
55222
to
support
the
Mn
health­
based
compliance
alternative
and
exclusion
of
Mn
from
the
TSM
analysis.

Four
commenters
disagreed
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0684,
OAR­
2002­

0058­
0693,
OAR­
2002­
0058­
0694)
with
the
appropriateness
and
lawfulness
of
the
Mn
healthbased
compliance
alternative
and
provided
several
reasons.
Two
commenters
(
OAR­
2002­
0058­

0683,
OAR­
2002­
0058­
0684)
stated
that
EPA
has
not
provided
a
justified
explanation
on
the
exclusion
of
Mn
from
the
calculation
of
TSM.
The
commenters
contended
that
although
EPA
39
found
the
MACT
floor
to
be
the
same
whether
or
not
Mn
was
included
in
the
floor
analysis,
this
reasoning
does
not
justify
removing
Mn
from
the
TSM
limit.

One
commenter
(
OAR­
2002­
0058­
0693)
stated
the
mechanism
through
which
the
Mn
compliance
alternative
operates
unlawfully
allows
plants
with
low
Mn
emissions
to
avoid
controlling
the
emissions
of
other
non­
mercury
metals.
Although
the
commenter
recognized
no
change
in
the
MACT
floor
analysis
for
TSM
based
on
seven
instead
of
eight
metals,
the
commenter
suggested
that
EPA
did
not
provide
and
explanation
of
this
result.
Further,
the
commenter
suggested
that
top­
performing
sources
used
to
calculate
the
MACT
floor
may
have
low
Mn
emissions
because
existing
controls
at
the
source
may
reduce
Mn
emissions,
such
that
the
TSM
emission
limit
would
not
be
affected
by
the
incorporation
of
Mn
concentrations.
The
commenter
emphasized
that
dirtier
sources
would
also
be
allowed
to
exclude
Mn
from
their
TSM
limit
calculations
and
as
a
result
be
allowed
to
emit
higher
levels
of
Mn
and
the
other
seven
metals
included
in
the
TSM
standard.

Response:
We
believe
the
alternative
TSM
emissions
limit
for
sources
that
qualify
for
the
health­
based
alternative
is
technically­
sound
and
supported
by
the
record.
The
alternative
emissions
limitation
set
forth
in
section
63.7507(
b)
of
subpart
DDDD
is
a
MACT
(
technology­
based)
standard
for
seven
metals
(
excluding
manganese).
This
alternative
MACT
emissions
limit
is
applicable
only
to
those
sources
who
qualify
for
the
health­
based
compliance
alternative
for
TSM
based
on
their
emissions
of
manganese.
The
manganese
emissions
from
these
sources
are
subject
to
the
health­
based
alternative
standard,
which
is
enforceable
through
the
operating
conditions
in
the
Title
V
permit
of
sources
that
successfully
demonstrate
eligibility
for
the
health­
based
alternative.
However,
the
remaining
seven
metals
that
are
included
in
the
TSM
calculation
must
still
be
subject
to
a
MACT
(
technology­
based)
emissions
limitation.
As
a
result,
we
derived
an
alternative
MACT
emissions
limit
for
these
seven
selected
metals
using
the
same
MACT
methodology
that
we
used
for
other
emissions
limits
in
subpart
DDDDD.
Only
sources
that
qualify
for
the
health­
based
alternative
for
TSM
are
eligible
to
apply
this
alternative
TSM
MACT
limit
in
section
63.7507(
b)
because
the
manganese
emissions
are
otherwise
controlled
to
health­
based
levels
through
the
operating
conditions
in
the
Title
V
permit
established
pursuant
to
appendix
A.

The
methodology
for
the
MACT
floor
analysis
conducted
for
establishing
this
40
alternative,
technology­
based
TSM
limit
is
described
in
the
memorandum
"
MACT
Floor
Analysis
for
the
Industrial,
Commercial,
and
Institutional
Boilers
and
Process
Heaters
National
Emission
Standards
for
Hazardous
Air
Pollutants"
in
the
docket.
When
we
investigated
the
possibility
of
establishing
an
alternative
TSM
emission
limit
for
these
7
metals,
we
performed
the
same
MACT
floor
analysis
that
we
conducted
for
the
TSM
emission
limit
for
8
metals.
That
is,
we
reexamined
the
emission
test
data
for
solid
fuel
units
that
included
emissions
results
for
all
of
the
eight
total
selected
metals
(
arsenic,

beryllium,
cadmium,
chromium,
lead,
manganese,
nickel,
and
selenium)
with
manganese
removed
from
the
summation.
The
technology­
based
TSM
limit
for
these
seven
metals
(
excluding
manganese)
resulted
in
a
MACT
floor
emission
level
for
existing
large
solid
fuel
units
of
0.001
lb/
mmBtu.
This
is
the
same
level
as
the
eight­
metal
(
including
manganese)

TSM
MACT
emission
level
proposed
and
promulgated
for
existing
large
solid
fuel
units.

Our
MACT
floor
analysis
for
new
solid
fuel
units
achieved
the
same
result.
Thus,
rather
than
repeating
the
emissions
limit
already
contained
in
Table
1
of
the
rule
in
section
63.7507(
b),
we
expressed
the
alternative,
technology­
based
TSM
limit
for
these
7
metals
for
eligible
sources
as
a
requirement
to
meet
the
same
emissions
limitation
without
counting
manganese.

The
seven­
metal
and
eight­
metal
technology­
based
TSM
limit
were
the
same
because
the
manganese
emissions
from
the
unit
serving
as
the
basis
for
the
limit
only
accounted
for
less
than
5
percent
of
the
total
selected
metals.
When
we
conducted
our
MACT
floor
analysis
for
the
seven
metals
standard,
we
determined
that
the
unit
we
used
as
the
basis
for
the
setting
the
TSM
limit
for
8
metals
was
the
same
as
the
unit
selected
under
the
analysis
for
7
metals.

We
understand,
but
do
not
agree
with
commenters
concerns
that
allowing
sources
to
exclude
manganese
from
their
TSM
limit
calculation
will
result
in
higher
emissions
of
the
other
seven
metals.
Based
on
the
available
data,
we
do
not
expect
sources
other
than
biomass­
fired
source
to
qualify
for
the
health­
based
alternative
for
manganese
and
TSM.

The
record
does
not
indicate
that
sources
using
biomass
fuels
emit
significant
quantities
of
metals
other
than
manganese.
Thus,
while
in
theory
the
exclusion
of
manganese
from
the
TSM
limitation
could
allow
an
eligible
source
to
increase
emissions
of
the
other
seven
metals,
the
record
does
not
indicate
that
eligible
sources
are
capable
of
doing
so.
41
The
TSM
limit
in
the
final
rule
was
included
at
proposal
because
the
Agency
was
sensitive
to
the
fact
that
some
sources
burn
fuels
(
e.
g,
biomass)
that
contain
very
little
metals
but
have
sufficient
PM
emissions
to
require
control
under
the
PM
provision
of
the
rule.
In
these
cases,
we
did
not
think
that
PM
would
be
an
appropriate
surrogate
for
metallic
HAP.
Under
the
rules
in
subpart
DDDDD,
a
source
may
choose
to
comply
with
the
alternative
TSM
emission
limit
instead
of
the
PM
limit.
The
eight
metals
included
in
the
TSM
summation
represent
the
most
common
and
the
largest
emitted
metallic
HAP
from
boilers
and
process
heaters.
Based
on
the
impacts
analysis
done
for
the
rule,
the
TSM
emission
limit
would
minimize
the
impacts
on
small
entities
(
e.
g.,
furniture
industry,
sugar
cane
industry)
since
some
of
the
potential
small
entities
burn
biomass.

Biomass
(
e.
g.,
wood,
bagasse,
peanut
hulls,
etc.)
generally
does
not
contain
measurable
amounts
of
metals
except
for
manganese.
For
example,
fuel
analyses
of
bagasse
from
sugar
cane
mills
in
Louisiana
did
not
detect
any
of
the
metals
except
for
manganese.

Fuel
analyses
of
bagasse
from
sugar
cane
mills
in
Florida
only
detected
manganese,
lead,

and
selenium,
with
lead
and
selenium
totaling
0.00032
lb/
MM
Btu,
and
this
is
assuming
that
all
the
metals
in
the
fuel
is
emitted
which
would
not
be
the
case
due
to
some
remaining
in
the
bottom
ash.
Wood
also
contains
little
metals
except
for
manganese.
Fuel
analyses
of
wood
combusted
as
fuel
at
three
furniture
facilities
detected
only
manganese.
Fuel
analysis
at
another
furniture
facility
did
detect
cadmium,
chromium,
and
nickel
beside
manganese,

but
the
total
of
those
three
metals
(
0.00005
lb/
MM
Btu)
was
only
1.3
percent
the
level
of
manganese
or
5
percent
of
the
TSM
limit.
Other
biomass
materials,
such
as
peanut
hulls,

used
as
fuel
also
have
similar
metals
composition.
Fuel
analysis
conducted
by
EPA
on
peanut
hulls
only
detected
the
presence
of
manganese.

The
metal
makeup
of
biomass
differs
greatly
from
coal.
Coal
contains
detectable
levels
of
all
8
metals.
Fuel
analyses
from
six
coal­
fired
facilities
indicate
that
even
if
a
coalfired
facility
could
demonstrate
eligibility
with
the
TSM
health­
based
compliance
alternative
and
may
exclude
manganese
emissions,
it
would
still
require
highly
efficient
PM
control
to
achieve
the
TSM
limit.
Thus,
when
we
promulgated
the
TSM
health­
based
compliance
alternative,
we
believed,
and
still
believe
that
only
biomass
units
will
seek
to
demonstrate
that
they
do
not
need
to
employ
PM
controls
by
showing
they
qualify
to
exclude
manganese
from
the
TSM
compliance
demonstration,
since
manganese
is
the
42
principal
metal
in
biomass
while
manganese
only
makes
up
a
small
fraction
of
the
metals
contained
in
coal.
43
Chapter
9
Deadline
for
Submission
of
Eligibility
Demonstration
Comment:
Multiple
commenters
(
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681,
OAR­

2002­
0058­
0688,
OAR­
2002­
0058­
0671,
OAR­
2002­
0058­
0681,
OAR­
2002­
0058­
0675,
OAR­

2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­

2002­
0058­
0698)
did
not
deem
it
necessary
for
the
Agency
to
extend
the
deadline
for
the
submission
of
eligibility
or
final
compliance
dates
provided
that
certain
timelines
and
components
of
the
health­
based
compliance
alternatives
were
maintained
as
a
result
of
this
reconsideration.

Three
commenters
(
OAR­
2002­
0058­
0672,
OAR­
2002­
0058­
0681,
OAR­
2002­
0058­
0688)
did
not
feel
an
extension
of
the
deadline
for
the
submission
of
eligibility
was
necessary
provided
that
this
reconsideration
is
completed
in
a
timely
manner.
One
commenter
(
OAR­
2002­
0058­
0681)

specified
a
timeframe
of
the
end
of
2005
for
the
conclusion
of
this
reconsideration.
Three
commenters
(
OAR­
2002­
0058­
0671,
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0665)
did
not
feel
it
was
necessary
for
the
Agency
to
extend
the
deadlines
for
submission
of
eligibility
or
compliance
on
the
condition
that
the
health­
based
compliance
alternative
remains
intact,
and
without
substantive
changes
to
the
present
format,
as
a
result
of
this
reconsideration
and
ongoing
litigation.
These
commenters
reasoned
a
change
to
the
health­
based
compliance
alternative
would
limit
the
available
compliance
options,
and
place
high
demand
on
the
associated
equipment
manufacturers
and
consulting
engineers
required
to
meet
deadlines.

One
commenter
(
OAR­
2002­
0058­
0665)
stated
that
governmental
organizations
will
require
more
time
than
private
industries
to
adjust
compliance
plans
due
to
funding
restrictions.

This
commenter
also
specified
additional
steps
the
EPA
should
take
in
the
event
that
major
changes
to
the
health­
based
compliance
alternative
methodologies
or
HI/
HQ
values
occur:
(
1)

alert
all
source
owners
who
have
submitted
Initial
Notification
Reports;
(
2)
ensure
affected
sources
are
allowed
to
comment
on
any
changes;
and,
(
3)
extend
the
deadline
to
three
years
after
promulgation
of
amendments.
44
Six
of
these
commenters
(
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­

0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­
2002­
0058­
0698)
requested
the
Agency
presume
the
extension
period
offered
in
112(
d)(
i)(
3)(
B)
is
available
to
all
affected
sources
in
contrast
to
an
extension
provision
that
would
require
approval
on
a
site­
specific
basis
by
the
associated
permitting
authority
only
if
this
reconsideration
substantially
alters
the
ability
of
small
municipal
generators
to
utilize
the
health­
based
compliance
alternatives.

Several
commenters
(
OAR­
2002­
0058­
0666,
OAR­
2002­
0058­
0669,
OAR­
2002­
0058­

0674,
OAR­
2002­
0058­
0695,
OAR­
2002­
0058­
0694,
OAR­
2002­
0058­
0687)
requested
that
the
Agency
consider
including
an
extension
of
at
least
one
year
to
both
the
submission
of
eligibility
and
final
compliance
dates
in
the
final
rule.
These
commenters
added
that
the
uncertainties
resulting
from
this
reconsideration
and
ongoing
litigation
have
made
the
original
deadlines
impractical.
One
commenter
(
OAR­
2002­
0058­
0687)
emphasized
that
it
is
necessary
to
maintain
a
one­
year
period
between
the
eligibility
demonstration
and
the
final
compliance
date
such
that
facilities
have
time
to
install
controls
if
they
fail
their
eligibility
demonstration.
The
commenter
added
that
there
are
limited
technical
resources,
equipment
vendors,
and
installation
contractors
available
to
develop
and
implement
control
based
compliance
strategies
in
the
event
that
the
health­
based
compliance
alternative
is
not
available.
One
commenter
(
OAR­
2002­
0058­
0694)

stated
that
the
Agency
should
consider
including
an
extension
to
the
deadline
for
submission
of
eligibility
because
permit
authorities
will
require
this
additional
time
in
order
to
process
the
eligibility
submissions
prior
to
the
MACT
compliance
date
if
the
health­
based
compliance
alternatives
remain
intact
as
a
result
of
this
reconsideration.
One
commenter
(
OAR­
2002­
0058­

0673)
requested
the
Agency
presume
the
extension
period
offered
in
112(
d)(
i)(
3)(
B)
is
available
to
all
affected
sources
in
contrast
to
an
extension
provision
that
would
require
approval
on
a
sitespecific
basis
by
the
associated
permitting
authority.
The
commenter
added
that
while
the
original
deadline
was
reasonable
at
promulgation,
the
deadline
is
no
longer
practical
due
to
an
uncertainty
of
whether
the
health­
based
compliance
alternative
will
remain
intact
as
a
result
of
both
this
reconsideration
and
ongoing
litigation.
The
commenter
projected
that
litigation
will
not
be
concluded
until
2007
and
stated
that
the
result
would
require
facilities
to
choose
between
risking
noncompliance
and
foregoing
the
health­
based
compliance
alternative
option.

One
commenter
(
OAR­
2002­
0058­
0693)
disagreed
with
the
need
to
extend
the
submission
of
eligibility
demonstration
or
compliance
dates
of
affected
sources
under
any
45
circumstances.
The
commenter
contended
that
an
extension
will
only
further
delay
sources'

installation
of
the
pollution
controls
that
are
required
by
the
Act.
The
commenter
also
stated
it
is
unlawful
to
extend
compliance
dates
of
affected
sources.
The
commenter
cited
42
U.
S.
Code
section
7412(
i)(
3)(
A)
" 
but
in
no
event
later
than
3
years
after
the
effective
date
of
such
standard"
to
support
this
claim.
This
commenter
emphasized
that
EPA
should
not
use
the
exemption
provided
for
in
section
112(
i)(
3)(
B)
for
sources
that
fail
eligibility
requirements
for
the
health­
based
compliance
alternatives
and
are
left
with
a
short
period
of
time
to
install
controls.

The
commenter
added
that
section
112(
i)(
3)(
B)
was
intended
to
be
used
only
when
technological
limitations
make
timely
compliance
impossible.

Response:
We
do
not
believe
it
is
appropriate
at
this
time
to
adjust
the
deadline
for
submitting
eligibility
demonstrations.
Most
commenters
representing
the
regulated
industry
believed
that
they
would
not
need
an
extension
if
EPA
met
certain
conditions.

EPA
has
met
the
conditions
outlined
by
these
commenters.
We
have
completed
the
reconsideration
in
a
timely
manner
and
have
not
made
significant
changes
to
the
rule.
As
stated
in
the
notice
of
reconsideration
(
70
FR
36913),
we
did
not
anticipate
that
significant
changes
would
be
made
as
a
result
of
this
reconsideration,
and
we
advised
affected
sources
to
"
proceed
to
prepare
their
eligibility
demonstrations
under
the
existing
process
promulgated
in
the
final
rule."
Although
we
are
making
some
clarifying
amendments,
we
are
not
changing
the
final
rule
substantially.
Thus,
this
action
will
not
have
the
impact
on
the
eligibility­
demonstration
process
that
concerned
several
other
commenters.
Therefore,

we
do
not
believe
an
extension
is
necessary
in
order
for
sources
to
complete
their
eligibility
demonstrations
by
September
2006.

In
addition,
we
do
not
have
cause
to
extend
the
compliance
date
for
existing
sources.

Section
112(
i)(
3)(
A)
of
the
CAA
specifies
that
NESHAP
for
existing
sources
can
have
compliance
dates
of
no
more
than
3
years.
For
the
ICI
boiler
and
process
heater
NESHAP,

EPA
provided
the
maximum
3
years
for
covered
sources
to
comply
with
the
new
standards.

It
is
not
unusual
for
promulgation
of
CAA
standards
to
be
followed
by
litigation
or
petitions
for
reconsideration.
Section
307(
b)(
1)
of
the
Act
specifically
provides
that
the
filing
of
a
petition
for
reconsideration
of
a
rule
does
not
postpone
the
effectiveness
of
a
rule.

To
date,
EPA
has
not,
during
the
pendency
of
a
reconsideration
request,
extended
the
46
compliance
deadlines
for
promulgated
MACT
standards
to
provide
compliance
periods
in
excess
of
the
statutory
3
year
maximum.
In
contrast,
where
the
Agency
has
amended
a
MACT
standard
in
a
significant
way
we
have
found
it
appropriate
to
set
a
new
compliance
date
for
the
rule
that
takes
into
account
new
requirements
not
contained
in
the
original
rule.

In
this
action
for
ICI
boilers
and
process
heaters,
we
are
making
relatively
minor
clarifying
amendments
to
the
eligibility
demonstration
methodology
for
the
health­
based
alternatives
and
have
not
reconsidered
or
changed
any
aspect
of
the
technology­
based
MACT
standards.
EPA
indicated
in
its
reconsideration
notice
that
we
were
unlikely
to
change
the
compliance
deadline
and
that
the
petitions
for
reconsideration
had
not
provided
new
information
suggesting
a
need
for
significant
changes
to
the
applicability
demonstration
methodology
for
the
health­
based
alternatives.
70
Fed.
Reg.
at
36910,

36913.
Thus,
affected
source
were
on
notice
that
significant
changes
to
health­
based
alternatives
were
not
anticipated,
Furthermore,
we
indicated
that
we
intended
to
complete
this
reconsideration
action
expeditiously
to
shorten
any
uncertainty
that
may
have
been
created
by
our
partial
granting
of
these
petitions
for
reconsideration.
70
Fed.
Reg.
at
36910.
The
time
required
to
complete
this
reconsideration
process
has
not
been
extraordinarily
lengthy.

We
disagree
with
the
request
to
provide
a
blanket
compliance
date
extension
for
all
sources
in
the
category
under
section
112(
i)(
3)(
B)
of
the
CAA.
The
granting
of
an
extension
under
this
provision
is
up
to
the
individual
permitting
authorities,
and
is
restricted
to
specific
situations
where
a
source
can
demonstrate
that
such
time
is
necessary
for
the
installation
of
controls.
We
have
not
been
provided
with
sufficient
evidence
to
show
that
all
sources
in
the
category
would
be
able
to
(
or
even
have
a
need
to)
make
such
a
showing.
47
Chapter
10
Proposed
Corrections
Comment:
Three
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0693,
OAR­

2002­
0058­
0694)
disagreed
with
the
proposed
correction
to
extend
the
risk­
based
exemptions
beyond
the
large
solid­
fuel
subcategory.
These
commenters
believed
the
expansion
of
the
healthbased
compliance
alternative
to
other
subcategories
to
be
significant
rule
change
which
would
require
a
separate
formal
rule
making
process
with
public
notice
and
a
comment
period.
These
commenters
expressed
concern
that
this
correction
will
allow
more
sources,
specifically
smaller
sources
with
shorter
stacks
that
tend
to
be
located
closer
to
populous
regions,
to
become
eligible
for
the
risk­
based
exemptions.
One
commenter
(
OAR­
2002­
0058­
0683)
added
that
the
analysis
of
TSM
contained
in
the
docket
was
specific
to
large
solid
fuel
units
and
not
all
units
in
which
the
proposed
correction
seeks
to
offer
applicability.
One
commenter
(
OAR­
2002­
0058­
0693)
cited
seven
sections
within
the
final
rule
language
that
specify
the
exemption
applicability
to
large
solid
fuel­
fired
sources.
Additionally,
the
commenter
contended
that
there
was
no
analysis
of
the
costs
or
emission
impacts
for
extending
the
exemptions
to
all
units.
The
commenter
referenced
docket
item
OAR­
2002­
0058­
606
to
show
that
the
current
analysis
excludes
other
unit
types.

Two
commenters
(
OAR­
2002­
0058­
0688,
OAR­
2002­
0058­
0672)
agreed
with
the
proposed
corrections
to
the
rule,
which
allowed
all
industrial
boilers
to
use
the
health­
based
compliance
alternatives.
The
commenters
added
that
there
is
no
technical
reason
why
the
type
of
unit
or
fuel
burned
should
restrict
a
facility
from
the
right
to
demonstrate
eligibility.

Response:
We
do
not
agree
that
a
separate
rulemaking
proceeding
is
necessary
to
adopt
the
proposed
correction
to
clarify
that
sources
in
all
subcategories
may
demonstrate
eligibility
for
the
health­
based
compliance
alternatives.
Although
this
correction
was
coupled
with
EPA's
response
to
a
Petition
for
Reconsideration,
EPA
has
provided
notice
and
an
opportunity
to
comment
on
the
proposed
changes
to
the
text
of
the
regulation
in
accordance
with
the
rulemaking
requirements
of
section
307(
d)
of
the
Clean
Air
Act.
48
Commenters
have
not
cited
legal
authority
in
the
Clean
Air
Act
or
elsewhere
that
requires
EPA
to
address
an
allegedly
"
significant"
change
to
a
rule
in
a
separate
or
independent
rulemaking
action.

We
acknowledge
that
our
original
intent
with
respect
to
the
scope
of
the
healthbased
compliance
alternatives
is
unclear
and
contradictory.
EPA
included
language
in
section
63.7507(
a)
of
the
rule
that
limits
the
applicability
of
the
health­
based
compliance
alternative
for
HCl
to
sources
in
the
large
solid­
fuel
fired
subcategory.
We
also
made
several
statements
in
the
preamble,
highlighted
by
the
commenters,
which
indicate
an
intent
to
limit
one
or
both
health­
based
alternatives
to
large
solid­
fuel
sources.
These
statements
were
made
because
the
existing
solid
fuel
fired
units
at
major
sources
are
the
main
category
of
sources
potentially
affected
by
the
health­
based
compliance
alternatives.

Furthermore,
the
number
of
new
small
solid
fuel
fired
units
at
major
sources
projected
in
the
future
(
see
Docket
item
OAR­
2002­
0058­
0024)
is
relatively
small.
However,
we
also
took
certain
actions
in
the
final
rule
which
show
an
intent
to
allow
sources
in
all
subcategories
to
demonstrate
eligibility
for
the
health­
based
compliance
alternatives.
For
example,
we
did
not
include
language
in
section
63.7507(
b)
of
the
rule
that
limits
the
health­
based
alternative
for
TSM
to
sources
in
the
large
solid
fuel
subcategory.
Likewise,

we
did
not
include
any
language
in
section
2
of
Appendix
A
limiting
the
health­
based
alternative
for
HCl
to
just
sources
in
the
large
solid­
fuel
subcategory.
In
that
provision,
we
said
that
"
each
new,
reconstructed,
or
existing
source
may
demonstrate
that
they
are
eligible
for
the
health­
based
compliance
alternatives."
Thus,
the
bottom
line
is
that
various
portions
of
September
14,
2004
final
rule
and
preamble
are
inconsistent
on
the
intended
scope
of
eligibility
for
the
health­
based
compliance
alternatives.

As
a
result
of
these
inconsistencies,
we
proposed
a
correction
that
would
make
these
elements
of
the
final
rule
consistent.
Although
we
indicated
in
the
proposal
that
this
correction
was
intended
to
reflect
our
original
intent,
we
agree
that
this
terminology
was
imprecise.
Given
the
conflicting
statements
and
regulatory
text
in
the
final
rule
cited
above,
we
concede
that
the
Agency's
original
intent
was
not
clear
one
way
or
the
other.
To
remedy
this
confusion,
we
are
resolving
the
inconsistency
by
eliminating
regulatory
language
that
could
be
read
to
limit
one
or
both
of
the
health­
based
alternatives
to
only
sources
in
the
large
solid
fuel
category.
Thus,
we
are
taking
the
action
we
proposed,
which
49
is
to
delete
the
words
"
for
large
solid
fuel
boilers
located
at
a
single
facility''
from
§

63.7507(
a)
and
the
words
``
Specified
for
the
Large
Solid
Fuel
Subcategory''
from
the
title
of
appendix
A.

Because
large
solid
fuel­
fired
units
are
not
the
only
units
that
have
applicable
Mn
and
HCl
MACT
limits,
we
believe
it
is
technically
correct,
and
appropriate,
to
allow
all
affected
sources
with
Mn
and
HCl
limits
the
opportunity
to
demonstrate
eligibility
for
the
health­
based
compliance
alternatives.
Where
EPA
has
determined
that
no
adverse
health
effects
are
expected
below
a
certain
threshold
level
of
exposure,
there
is
no
reasoned
basis
for
precluding
smaller
industrial
boilers
and
process
heaters
from
using
the
health­
based
compliance
alternative
so
long
as
their
emissions
do
not
result
in
human
exposure
above
the
designated
threshold
value.
To
the
extent
we
are
expanding
the
availability
of
the
healthbased
compliance
alternative
to
all
sources;
this
will
not
subject
the
public
to
adverse
health
effects.

We
do
not
believe
health
risks
are
increased
by
allowing
smaller
sources
to
qualify
for
the
health­
based
compliance
alternatives,
even
if
the
commenters
are
correct
that
these
sources
tend
to
have
shorter
stacks
and
are
closer
to
populous
areas.
The
changes
we
are
making
in
this
rule
do
not
automatically
make
all
small
sources
eligible
for
the
health­
based
compliance
alternatives.
Such
sources
must
still
demonstrate
eligibility
under
the
procedures
and
criteria
in
Appendix
A,
which
consider
stack
heights
and
distance
to
populated
areas
in
determining
eligibility.
If
these
characteristics
indicate
that
a
particular
source
has
emissions
that
pose
risks
above
the
threshold
levels,
the
source
will
not
be
eligible
for
the
health­
based
compliance
alternative.
In
addition,
emissions
rates
are
also
part
of
the
analysis
under
appendix
A.
Because
small
sources
have
lower
emissions
rates,

all
other
things
being
equal,
small
sources
present
less
risk
than
large
sources.

We
do
not
believe
this
correction
to
the
rule
requires
an
extensive
re­
analysis
of
the
cost
or
emissions
reduction
impacts
of
the
health­
based
compliance
alternatives.
We
have
sufficient
information
to
conclude
that
this
correction
will
not
result
in
a
meaningful
change
to
the
cost
or
emissions
impacts
of
the
rule.

In
the
final
rule,
the
cost
and
economic
analyses
developed
as
part
of
the
final
MACT
rulemaking
were
based
on
the
estimated
costs
for
all
affected
sources
to
install,

maintain,
and
operate
controls
and
to
comply
with
MACT
requirements.
Costs
were
not
50
based
on
the
health­
based
compliance
alternatives
since
the
cost
of
compliance
with
controls
is
significantly
higher
than
the
cost
to
comply
with
the
health­
based
compliance
alternatives.
The
costs
associated
with
voluntarily
conducting
risk
analyses
were
not
analyzed
and
therefore
not
re­
analyzed
to
account
for
this
correction
to
the
applicability
of
the
health­
based
alternatives
to
all
affected
units.

Our
supplemental
analysis
of
the
impact
on
control
costs
and
emissions
reductions
resulting
from
adoption
of
the
health­
based
alternatives
cited
by
commenter
(
OAR­
2002­

0058­
606)
showed
that
the
estimated
costs
of
the
final
rule
would
be
lower
if
the
healthbased
provisions
were
adopted.
This
"
rough
assessment"
of
the
number
of
sources
that
would
qualify
for
the
health­
based
alternatives
focused
on
large
sources
because
these
sources
were
the
sources
most
likely
to
seek
to
demonstrate
eligibility
to
comply
with
the
health­
based
alternatives.

Based
on
the
available
information
on
sources
in
the
category,
we
do
not
expect
this
correction
to
enable
a
significant
number
of
additional
sources
to
qualify
for
the
healthbased
alternatives.
Thus,
this
correction
to
the
rule
will
not
result
in
a
dramatic
difference
in
our
rough
control
cost
and
emissions
reduction
estimates.
Since
we
evaluated
the
costs
of
the
rule
without
the
health­
based
compliance
alternatives,
we
have
no
reason
to
believe
this
change
will
increase
compliance
costs
above
these
high­
end
estimates.
The
analysis
we
have
conducted
in
this
reconsideration
proceeding
is
sufficient
to
enable
us
to
conclude
that
compliance
costs
will
not
be
significantly
different
if
a
few
additional
sources
are
able
to
demonstrate
eligibility
as
a
result
of
this
correction.
For
similar
reasons,
we
do
not
have
a
basis
to
believe
this
change
dramatically
alters
the
emissions
reductions
that
will
be
achieved
under
the
rule.

We
adopted
the
health­
based
alternatives
in
part
to
reduce
the
compliance
costs
of
the
NESHAP
while
continuing
to
maintain
the
health
protection
called
for
in
the
Clean
Air
Act.
The
potential
for
this
correction
to
reduce
compliance
costs
further
does
not
undermine
this
reason
for
adopting
health­
based
compliance
alternatives.
We
did
not
rely
on
these
cost
and
emission
reduction
estimates
as
a
basis
for
establishing
technology­
based
MACT
emissions
limitations
or
the
eligibility
criteria
for
the
health­
based
compliance
alternatives.
We
conducted
the
cost
and
emission
reduction
estimates
in
order
to
present
a
summary
of
the
environmental
and
economic
impacts
of
final
rule.
The
estimates
included
51
in
our
supplemental
analysis
of
the
impact
on
control
costs
and
emission
reductions
were
presented
in
order
to
provide
a
comparative
summary
of
impacts
of
the
final
rule
based
on
a
rough
estimate
of
facilities
that
might
opt
to
comply
with
the
health­
based
compliance
alternatives.
Additionally,
these
cost
estimates
are
necessary
in
order
complete
several
Statutory
and
Executive
Order
Reviews
including:
The
Paperwork
Reduction
Act,
The
Regulatory
Flexibility
Act,
and
The
Unfunded
Mandates
Reform
Act
of
1995.
52
Chapter
11
Review
of
Eligibility
Demonstrations
for
Health­
Based
Compliance
Alternatives
and
Title
V
Permit
Conditions
11.1
Eligibility
and
Permit
Authority
Review
Comment:
Three
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0670,
OAR­

2002­
0058­
0684)
believed
that
applicability
of
the
health­
based
compliance
alternatives
depends
on
approval
from
a
permitting
authority
via
issuance
of
a
Title
V
permit
that
includes
enforceable
alternative
limits.
One
of
these
commenters
(
OAR­
2002­
0058­
0670)
requested
that
EPA
clarify
in
sections
9
and
10
of
appendix
A
that
each
facility's
compliance
with
health­
based
compliance
alternative
is
dependent
on
the
approval
from
a
permitting
authority
via
issuance
of
a
Title
V
permit
that
includes
the
alternative
limits.
The
commenter
added,
if
the
off­
ramp
risk
determination
is
not
approved,
the
facility
must
comply
with
the
NESHAP
requirements.
Two
commenters
(
OAR­
2002­
0058­
0670,
OAR­
2002­
0058­
0684)
stated
that
permitting
authorities
have
the
authority
to
disapprove
a
risk
assessment
demonstration
if
it
is
deemed
incomplete
or
incorrect.
One
commenter
(
OAR­
2002­
0058­
0694)
requested
a
clarification
in
the
rule
to
specify
the
authority
of
a
permitting
agency
to
verify
or
reject
flawed
submittals
for
eligibility
to
the
health­
based
compliance
alternatives
at
both
tiers.

One
commenter
(
OAR­
2002­
0058­
0667)
opposed
a
requirement
to
obtain
EPA
or
state
agency
approval
of
the
site­
specific
risk
assessments
as
currently
stated
in
the
HWC
rule.
The
commenter
believed
that
requiring
approval
would
likely
create
delays
in
the
eligibility
process
and
result
in
very
short
compliance
timelines
if
a
reviewing
authority
rejected
a
site­
specific
assessment
or
did
not
complete
the
review
in
a
timely
manner.
The
commenter
added
there
is
no
technical
justification
for
requiring
approval
in
the
HWC
MACT
rule
and
recommended
not
doing
so
in
the
boiler
and
process
heater
rule.

Response:
We
agree
that
the
preferred
approach
is
to
not
require
affirmative
approval
by
the
permitting
authority
of
each
risk
assessment
before
a
source
is
eligible
to
53
comply
with
the
health­
based
alternative.
Thus,
under
the
procedures
in
Appendix
A
of
subpart
DDDDD,
as
revised
in
this
rule,
a
source
becomes
eligible
to
comply
with
the
health­
based
alternatives
at
the
time
its
submits
an
eligibility
demonstration
meeting
the
requirements
of
section
8
of
Appendix
A.

However,
for
a
source
to
remain
eligible
to
comply
with
the
health­
based
alternatives,
the
eligibility
demonstration
must
be
complete
and
the
application
for
a
permit
modification
must
ultimately
be
approved
by
the
permitting
authority.
Thus,
as
part
of
this
process,
permitting
agencies
do
have
the
authority
to
review
eligibility
demonstrations
to
verify
that
they
meet
the
requirements
of
Appendix
A
and
are
technically
sound.
For
example,
a
permitting
authority
may
notify
a
source
that
its
eligibility
demonstration
is
deficient
if
the
demonstration
is
incomplete
or
if
a
look­
up
table
analysis
is
performed
in
a
situation
when
site­
specific
conditions
exist
that
make
the
use
of
the
look­
up
tables
inappropriate.
Based
upon
the
technical
findings
of
the
review,

permitting
agencies
have
the
authority
to
inform
a
source
that
it
is
no
longer
eligible
for
the
health­
based
alternative
if
the
eligibility
demonstration
is
deficient.
EPA
will
also
review
some
demonstrations
as
part
of
an
audit
program.

This
review
authority
derives
from
the
Title
V
permit
program
through
which
the
health­
based
compliance
alternatives
are
implemented,
and
it
was
inherent
in
the
rule
when
promulgated
on
September
14,
2004.
Subpart
DDDDD
contains
applicable
requirements
that
are
incorporated
in
Title
V
permits.
The
Title
V
permit
program
provides
a
process
for
identifying
and
consolidating
all
of
the
applicable
requirements
for
each
source.
Through
this
process,
the
permit
authority
reviews
each
application
to
verify
the
applicable
requirements
for
each
source.
Thus,
when
a
source
submits
a
demonstration
of
eligibility
for
the
health­
based
alternatives
in
subpart
DDDDD,
the
Title
V
permitting
authority
has
the
ability
to
review
this
submission
to
determine
whether
the
applicable
requirements
for
that
source
are
the
health­
based
or
the
technology­
based
requirements
in
subpart
DDDDD.

However,
to
clarify
this
issue,
we
are
adding
explicit
language
in
sections
10
and
11
of
appendix
A
to
make
clear
that
permitting
agencies
may
review
each
facility's
eligibility
demonstration.
If
the
permitting
authority
identifies
deficiencies
with
the
eligibility
determination
or
the
permit
modification
is
eventually
disapproved
based
on
technical
54
problems
with
the
eligibility
demonstration,
then
the
facility
is
no
longer
eligible
for
the
health­
based
alternative
and
must
comply
with
the
MACT
emission
standards
by
the
compliance
dates
specified
in
63.7495.

For
new
sources,
we
are
establishing
a
slightly
different
procedure
because
new
sources
will
be
relying
upon
the
health­
based
alternative
at
start­
up.
In
these
cases,
the
source
will
have
a
grace
period
of
30
to
90
days
to
correct
any
deficiencies
before
ceasing
to
be
eligible
for
the
health­
base
alternative.
This
grace
period
is
not
needed
for
existing
sources
because
their
eligibility
demonstrations
must
be
submitted
12
months
prior
to
the
compliance
date.
We
believe
this
provides
sufficient
time
for
permitting
authorities
to
notify
sources
of
any
deficiencies
and
for
a
source
to
correct
any
deficiencies.

Comment:
Three
commenters
(
OAR­
2002­
0058­
0666,
OAR­
2002­
0058­
0669,
OAR­

2002­
0058­
0674)
requested
that
EPA
clarify
the
deadline
for
compliance
for
sources
whose
health­
based
eligibility
determination
is
found
to
be
deficient
.
These
commenters
also
suggested
an
allowance
period
of
12
months
after
the
facility
receives
notice
of
a
deficiency
in
their
healthbased
eligibility
determination.

Two
commenters
(
OAR­
2002­
0058­
0676,
OAR­
2002­
0058­
0677)
stated
that
the
healthbased
compliance
alternative
will
delay
compliance
with
MACT
for
sources
that
attempt
to
unsuccessfully
demonstrate
eligibility
with
the
health­
based
compliance
alternatives.

Response:
We
disagree
that
there
will
be
a
delay
in
compliance
caused
by
the
health­
based
compliance
alternatives.
Sources
that
submit
eligibility
demonstrations
in
an
attempt
to
comply
with
the
health­
based
compliance
alternative
but
do
so
unsuccessfully
must
still
be
in
compliance
within
3
years
after
the
standard
was
promulgated.
We
do
not
believe
it
is
appropriate
to
automatically
extend
the
compliance
date
in
these
situations.
As
noted
above,
for
existing
sources,
there
is
a
one­
year
window
in
which
permitting
authorities
and
sources
can
work
out
any
deficiencies
in
an
eligibility
demonstration.
The
health­
based
compliance
alternative
is
an
optional
compliance
approach.
Some
risk
is
involved
in
electing
to
comply
with
the
MACT
standard
via
the
health­
based
compliance
alternatives.
This
assumed
risk
could
include
a
shorter
amount
of
time
to
install
the
controls
that
are
required
to
meet
technology
standards
in
the
event
that
a
source
does
not
submit
a
health­
based
eligibility
demonstration
that
meets
the
requirements
of
Appendix
A.
We
do
not
necessarily
endorse
the
use
section
112(
i)(
3)(
B)
to
grant
compliance
date
55
extensions
in
these
circumstances.
However,
we
will
leave
the
decision
of
whether
to
grant
such
a
compliance
date
extension
on
a
site­
specific
basis
to
permitting
authorities.

11.2
Significant
Permit
Modifications
Comment:
One
commenter
(
OAR­
2002­
0058­
0688)
disagreed
with
the
Agency's
basis
for
concluding
that
the
incorporation
of
the
health­
based
compliance
alternatives
into
a
Title
V
permit
would
require
a
significant
permit
modification
under
Title
V
requirements,
although
the
commenter
did
not
disagree
that
a
significant
permit
modification
process
would
be
appropriate.

The
comment
believes
that
the
minor
permit
modification
"
gatekeeper"
contained
in
40
CFR
§

70.7(
e)(
2)(
i)(
A)(
4)
of
our
regulations
is
not
applicable
because
there
is
an
underlying
applicable
requirement
reflected
in
the
NESHAP.
Instead,
according
to
the
commenter
,
EPA
should
rely
on
the
gatekeeper
in
40
CFR
§
70.7(
e)(
2)(
i)(
A)(
3)
which
prohibits
use
of
minor
modification
procedures
where
a
provision
would
require,
or
change,
a
case­
by­
case
determination
of
an
emission
limitation
or
another
standard
during
the
Title
V
permit
process.
The
commenter
added
that
this
provision
ensures
when
the
Title
V
process
is
the
vehicle
for
establishing
the
limit
for
a
facility,
as
opposed
to
incorporating
citations
from
existing
rules,
significant
modification
procedures
apply.
The
commenter
concluded
that
the
Title
V
procedures
apply
because
there
is
no
other
permit
or
regulation
that
includes
the
appropriate
level
of
process
for
the
health­
based
compliance
alternatives.

Response:
We
partially
agree
and
partially
disagree
with
the
commenter.
After
further
consideration
of
the
issue,
EPA
agrees
with
the
commenter
that
we
should
not
have
concluded
that
significant
permit
modifications
procedures
would
apply
on
the
basis
of
the
minor
permit
modification
gatekeeper
in
40
CFR
70.7(
e)(
2)(
i)(
A)(
4).
However,
after
further
consideration
of
this
issue,
we
believe
that
permitting
authorities
should
rely
on
the
reopening
provisions,
rather
than
the
significant
permit
modification
process,
when
the
health­
based
alternatives
are
initially
incorporated
into
an
existing
Title
V
permit.

The
health­
based
compliance
alternatives
are
emissions
limitations
based
on
section
112(
d)(
4)
of
the
Act.
These
limitations
are
alternative
standards
for
threshold
pollutants
based
on
health
considerations,
rather
than
the
technology­
based
MACT
criteria.
As
a
56
result,
EPA
considers
the
health­
based
alternatives
to
be
applicable
requirements
in
the
same
manner
that
the
MACT­
based
emissions
limitations
contained
in
40
CFR
Part
63,

Subpart
DDDDD
are
also
applicable
requirements.
See
the
definition
of
"
applicable
requirement"
found
in
40
CFR
70.2
and
71.2.
The
applicable
requirements
under
the
health­
based
alternatives
include
the
parameters
that
define
the
affected
source
as
eligible
for
the
health­
based
compliance
alternatives.
Thus,
sources
that
successfully
demonstrate
eligibility
to
comply
with
the
health­
based
alternatives
instead
of
the
technology­
based
MACT
standards
are
selecting
among
two
different
sets
of
applicable
requirements
under
Subpart
DDDDD.

Given
that
the
health­
based
alternative
emissions
standards
that
result
from
the
process
outlined
in
the
ICI
boiler
and
process
heater
NESHAP
are
applicable
requirements,

the
initial
incorporation
of
these
applicable
requirements
into
an
existing
title
V
permit
should
be
accomplished
using
the
reopening
provisions
found
in
40
CFR
70.7(
f)(
1)(
i)
or
71.7(
f)(
1)(
i).
Section
70.7(
f)(
1)(
i)
specifies
that
a
permit
shall
be
reopened
and
revised
when
"
additional
applicable
requirements
under
the
Act
become
applicable
to
a
major
Part
70
source 
."
Regardless
of
which
of
the
applicable
requirements
is
being
incorporated
into
the
permit
of
a
boiler
or
process
heater
(
whether
technology­
based
or
health­
based),
the
process
for
incorporating
additional
applicable
requirements
into
title
V
permits
should
follow
the
procedures
outlined
in
the
reopening
provisions
of
40
CFR
§
70.7(
f)(
1)(
i)
or
§

71.7(
f)(
1)(
i).
This
approach
is
consistent
with
what
we
said
in
our
recent
rule
for
Hazardous
Waste
Combustors.

We
do
not
agree
with
the
commenter
that
the
Title
V
permit
process
is
the
vehicle
for
establishing
the
limits
that
apply
to
each
facility
that
demonstrates
eligibility
for
the
health­
based
compliance
alternatives
in
the
ICI
boilers
and
process
heater
NESHAP.
It
is
important
to
clarify
that
the
alternative
health­
based
emissions
standards
are
created
under
the
authority
of
section
112(
d)(
4)
and
pursuant
to
the
process
outlined
in
Appendix
A
of
the
Part
63,
Subpart
DDDDD.
Title
V
does
not
provide
authority
to
create
applicable
requirements
under
section
112;
but
rather,
it
is
title
V's
role
to
incorporate
applicable
requirements,
such
as
Subpart
DDDDD,
that
are
established
under
other
provisions
of
the
Clean
Air
Act.
57
If
the
parameters
that
are
incorporated
into
a
Title
V
permit
based
on
the
healthbased
alternative
in
the
ICI
boiler
NESHAP
need
to
be
modified
after
the
initial
incorporation
due
to
a
change
subject
to
section
11
of
Appendix
A
of
the
NESHAP,
we
agree
that
a
significant
permit
modification
process
might
need
to
be
used.
However,

contrary
to
our
earlier
response
to
comments,
EPA
agrees
with
the
commenter
that
the
gatekeeper
in
section
70.7(
e)(
2)(
i)(
A)(
4)
may
not
be
relevant
under
the
ICI
boiler
and
process
heater
NESHAP.
The
section
70.7(
e)(
2)(
i)(
A)(
4)
gatekeeper
says
that
minor
permit
modification
procedures
may
be
used
for
permit
modifications
that
"
Do
not
seek
to
establish
or
change
a
permit
term
or
condition
for
which
there
is
no
corresponding
underlying
applicable
requirement
and
that
the
source
has
assumed
to
avoid
an
applicable
requirement
to
which
the
source
would
otherwise
be
subject...."

We
agree
that
this
gatekeeper
may
not
apply
because
a
source
subject
to
the
alternative
health­
based
emission
standard
under
the
ICI
boiler
and
process
heater
NESHAP
is
subject
to
an
underlying
applicable
requirement
and
is
not
assuming
additional
Title
V
permit
conditions
in
order
to
avoid
the
applicable
requirements
in
Subpart
DDDDD.
Rather,
such
a
source
submits
an
eligibility
demonstration
(
under
the
procedures
set
forth
in
Subpart
DDDDD)
to
establish
eligibility
for
an
alternative
applicable
requirement
derived
from
the
same
NESHAP.

11.3
Enforceable
Parameters
Comment:
Four
commenters
(
OAR­
2002­
0058­
0670,
OAR­
2002­
0058­
0677,
OAR­

2002­
0058­
0694,
OAR­
2002­
0058­
0683)
requested
that
EPA
specify
several
additional
process
and
non­
process
related
parameters
under
section
11
of
appendix
A
to
clarify
the
enforceable
alternative
limits
for
the
facility.
One
commenter
(
OAR­
2002­
0058­
0670)
specifically
requested
that
"
emission
rate"
be
added
to
the
list
of
parameters.
Three
commenters
(
OAR­
2002­
0058­

0677,
OAR­
2002­
0058­
0694,
OAR­
2002­
0058­
0683)
requested
that
non­
process
parameters
that
can
affect
a
change
in
the
air
dispersion
modeling
be
included,
such
as
stack
height,
exit
gas
temperature,
distance
to
the
plant
property
line,
and
changes
in
RfCs
or
land­
use.
One
commenter
(
OAR­
2002­
0058­
0683)
stated
that
in
order
for
a
source
to
certify
compliance
with
the
health­
based
compliance
alternatives,
the
parameters
defining
the
affected
source
must
not
be
58
limited
to
process
parameters,
and
suggested
that
key
inputs
to
a
facility's
demonstration
of
eligibility
(
e.
g.,
RfCs,
look­
up
table
values,
emission
rates
,
etc )
be
added
to
the
list
of
enforceable
conditions
that
must
be
submitted
for
incorporation
in
the
Title
V
permit.

Response:
We
recognize
that
a
large
number
of
parameters
can
affect
continuous
compliance
with
the
health­
based
compliance
alternatives.
These
parameters
include,
but
are
not
limited
to,
HAP
emission
rates,
fuel
type,
type
of
control
device,
stack
parameters,

reference
values,
and
location
of
local
residences.
Some
of
these
parameters
are
appropriate
for
incorporation
into
Title
V
permits
(
e.
g.,
HAP
emission
rates
or
a
surrogate
for
emission
rate
such
as
production
volume)
while
others
are
not
(
e.
g.,
reference
values).

However,
changes
in
any
of
these
parameters
can
trigger
the
need
for
a
re­
assessment.

Therefore,
we
are
adding
language
to
Appendix
A
expanding
the
list
of
parameters
that
should
be
considered
for
inclusion
as
enforceable
permit
limits.
In
section
11
of
Appendix
A,
we
are
also
expanding
the
list
of
parameters
that,
if
changes
occur,
could
also
necessitate
a
re­
assessment.

Comment:
One
commenter
(
OAR­
2002­
0058­
0684)
requested
that
sources
eligible
for
the
health­
based
compliance
alternative
be
required
to
review
all
modeling
parameters
annually
including
both
process
and
non­
process
parameters
in
order
to
ensure
continuous
compliance.

The
commenter
suggested
this
review
could
become
part
of
the
Title
V
certifications.

Another
commenter
(
OAR­
2002­
0058­
0670)
requested
additional
language,
similar
to
section
13
of
Appendix
B
the
Plywood
and
Composite
Wood
Products
NESHAP,
which
identifies
steps
to
be
taken
if
process
and
non­
process
parameters
of
the
risk
based
compliance
demonstration
change.
The
commenter
suggested
that
the
rule
(
1)
specify
non­
process
parameters
that
can
affect
continuous
compliance
with
the
health­
based
compliance
alternatives;
(
2)
require
facilities
to
annually
certify
continuous
compliance
with
all
process
and
non
process
parameters
used
in
the
risk
determination;
and
(
3)
provide
a
timeline
for
the
facility
to
come
into
compliance
based
on
a
change
in
a
process
or
non
process
parameter.
The
commenter
added
that
the
current
rule
does
not
consider
changes
to
non­
process
parameters,
whereas
both
process
and
non­
process
parameters
are
evaluated
during
annual
Title
V
compliance
certifications
under
the
Plywood
and
Composite
Wood
Products
NESHAP.

Response:
Sources
that
demonstrate
eligibility
for
the
health­
based
compliance
alternatives
and
have
the
necessary
conditions
incorporated
in
their
Title
V
permits
are
59
subject
to
the
normal
Title
V
permitting
requirements
set
forth
in
40
CFR
Part
70
and
state
regulations.
This
includes
the
requirement
for
compliance
certifications
at
least
annually
based
on
40
CFR
70.6(
c)(
5)
and
equivalent
state
provisions.
Thus,
on
at
least
an
annual
basis,
sources
will
have
to
review
and
certify
their
compliance
with
their
Title
V
permit
conditions,
including
those
conditions
that
implement
the
health­
based
alternatives
in
this
rule.

However,
we
do
not
believe
that
sources
should
be
required
to
submit
a
new
eligibility
demonstration
each
year.
Under
the
final
rule,
sources
are
only
required
to
resubmit
the
eligibility
demonstration
if
parameters
included
in
their
risk
assessment
change
in
a
way
that
could
increase
risks.
These
parameters
include,
but
are
not
limited
to,

fuel
type,
fuel
mix
(
annual
average),
reference
values,
type
of
control
device,
emission
rate,

stack
parameters,
and
location
of
local
residences.
We
agree
that
both
process
and
nonprocess
parameters
can
impact
risk
and,
therefore,
changes
in
both
types
of
parameters
could
necessitate
a
re­
assessment.
We
have
added
language
to
this
effect
in
sections
10
and
11
of
appendix
A.

If
a
change
results
in
a
source
no
longer
being
eligible
for
the
health­
based
alternative
compliance
options,
then
that
source
must
comply
with
the
technology
requirements
of
the
MACT.
Further,
63.9(
j)
of
the
MACT
general
provisions
requires
that
a
source
must
provide
permitting
authorities
with
any
changes
to
information
already
provided
in
the
notification
of
compliance
status
within
15
calendar
days
after
the
change.

The
notification
of
compliance
status
includes
the
methods
used
to
determine
compliance.

We
believe
that
these
requirements
to
conduct
the
regular
Title
V
compliance
certification
and
to
resubmit
the
eligibility
demonstration
when
there
is
a
change
that
could
increase
risks
are
adequate
to
ensure
continuous
compliance.
With
regard
to
the
timeline
requested
by
one
commenter,
appendix
A
indicates
that
if
a
parameter
changes
that
is
within
the
source's
control,
such
as
a
change
in
stack
height
at
the
facility,
the
updated
eligibility
demonstration
must
be
submitted
prior
to
making
the
change
and
revising
the
Title
V
permit.
If
the
source
is
no
longer
eligible
for
the
health­
based
compliance
alternatives,
that
source
must
come
into
compliance
with
the
technology
standards
prior
to
making
the
change
and
revising
the
permit.
We
have
also
added
language
to
section
11
indicating
that
if
a
parameter
changes
that
is
outside
the
control
of
the
source
(
e.
g.,
a
60
change
in
a
reference
value),
and
that
change
causes
the
source
to
no
longer
be
able
to
meet
the
criteria
for
the
health­
based
compliance
alternatives,
the
source
is
allowed
a
3
year
timeline
to
come
into
compliance
with
the
technology
standards.
61
Chapter
12
Miscellaneous
12.1
Wording
Changes/
Additions
Comment:
One
commenter
(
OAR­
2002­
0058­
0670)
requested
EPA
incorporate
the
RfCs
from
EPA
website
into
the
final
rule
as
opposed
to
a
reference
to
the
website.
The
commenter
also
requested
that
EPA
maintain
and
update
the
tables
in
the
rule
as
RfCs
change
in
the
future.

Response:
We
disagree
with
this
suggestion.
Referencing
the
toxicity
tables,
located
on
EPA's
website,
provides
an
efficient
mechanism
for
adapting
to
scientific
advances
without
requiring
extensive
revision
to
the
regulatory
text
when
a
reference
value
changes.

12.2
Decision
to
Adopt
Health­
Based
Compliance
Alternatives
Comment:
Several
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0676,
OAR­

2002­
0058­
0677,
OAR­
2002­
0058­
0660,
OAR­
2002­
0058­
0677,
OAR­
2002­
0058­
0684)

disapproved
of
incorporating
the
health­
based
compliance
alternatives
into
the
Boiler
and
Process
Heater
MACT
standard.
Four
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0676,
OAR­

2002­
0058­
0677,
OAR­
2002­
0058­
0660)
disagreed
with
the
authority
for
EPA
to
implement
health­
based
compliance
alternatives
as
part
of
the
MACT
standard.
Both
commenters
added
that
the
MACT
standards
are
technology­
based
standards,
not
risk
based
and
that
these
risk­
based
health­
based
compliance
alternatives
contradict
provisions
of
the
1990
amendments
to
the
CAA.

One
commenter
(
OAR­
2002­
0058­
0683)
added
that
the
risk­
based
approach
was
to
be
used
separately
and
subsequently
during
residual
risk
evaluations
to
improve
a
technology­
based
standard.
One
commenter
(
OAR­
2002­
0058­
0660)
stated
this
major
objective
to
reduce
compliance
costs
for
sources
through
the
health­
based
compliance
alternatives
is
in
violation
with
section
8
of
the
U.
S.
Constitution.

Several
other
commenters
(
OAR­
2002­
0058­
0667,
OAR­
2002­
0058­
0668,
OAR­
2002­

0058­
0671,
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0696,
OAR­
2002­

0058­
0697,
OAR­
2002­
0058­
0698,
OAR­
2002­
0058­
0688)
believed
that
EPA
acted
within
62
statutory
authority
to
implement
the
health­
based
compliance
alternatives
for
Mn
and
HCl,

recognized
threshold
pollutants,
under
section
112(
d)(
4).
One
commenter
(
OAR­
2002­
0058­

0667)
provided
an
attachment
of
the
comments
made
in
response
to
the
HWC
MACT
"
Replacement
Standards"
proposal,
to
support
EPA's
authority
to
develop
health­
based
compliance
alternatives.
Several
of
these
commenters
cited
a
1990
Senate
report
to
support
the
Agency's
authority.

Response:
As
stated
in
the
comment
summary
in
final
boiler
and
process
heater
NESHAP
rule
Promulgated
on
September
13,
2004,
we
have
determined
that
we
have
the
legal
authority
to
establish
health­
based
alternative
emission
standards
for
HCl
and
manganese
for
affected
sources
in
this
category
pursuant
to
the
authority
provided
under
section
112(
d)(
4)
of
the
CAA.
This
reconsideration
only
opened
comments
on
the
certain
provisions
of
the
approach
for
demonstrating
eligibility
under
appendix
A
and
on
the
provisions
for
establishing
the
health­
based
compliance
alternative
for
TSM.
We
are
not
reconsidering
our
legal
authority
to
implement
health­
based
compliance
alternatives.
For
further
explanation
of
our
legal
basis
for
adopting
the
health­
based
alternative,
see
the
Response
to
Comments
documents
associated
with
our
September
14,
2004
final
rule.

Comment:
Three
commenters
(
OAR­
2002­
0058­
0677,
OAR­
2002­
0058­
0683,
OAR­

2002­
0058­
0686)
suggested
that
the
risk­
based
alternatives
remove
the
level
playing
field
benefit
of
national
technology­
based
regulations,
and
as
a
result
would
encourage
industries
to
move
to
areas
with
less
stringent
air
toxics
regulations
and
thus
create
`
hot
spots'
of
HAP.
One
commenter
(
OAR­
2002­
0058­
0683)
concluded
that
a
national
technology­
based
approach
is
necessary
based
on
the
results
of
the
NATA,
which
indicated
high
levels
of
HAP
in
both
rural
and
urban
areas.

Response:
We
disagree
with
the
commenters
and
contend
that
the
inclusion
of
health­
based
compliance
alternatives
in
the
final
rule
is
appropriate.
By
using
this
approach,
EPA
is
availing
itself
of
the
authority
Congress
granted
it
in
section
112(
d)(
4)
of
the
CAA.
The
requirements
of
the
health­
based
compliance
alternatives
are
the
same
for
all
sources
across
the
nation.
These
requirements
will
ensure
that
affected
sources
which
choose
to
comply
with
the
health­
based
alternatives
do
not
emit
HCl,
Cl2,
and/
or
manganese
at
levels
that
are
harmful
to
public
health.
We
do
not
agree
that
our
rule
will
result
in
"
hot
spots"
where
the
risk
from
HAP
emissions
in
some
area
is
higher
than
in
63
other
areas.
The
risk­
based
eligibility
criteria
are
the
same
in
all
areas
of
the
country.
No
matter
where
a
source
locates,
it
is
not
eligible
to
comply
with
the
health­
based
alternatives
if
it
emits
manganese
or
HCl
at
levels
that
results
in
health
risk
above
the
applicable
thresholds.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0676,
OAR­
2002­
0058­
0677)
stated
that
the
health­
based
compliance
alternatives
ignore
the
threat
of
fine
particulates.
The
commenters
suggested
the
transport
of
fine
particulates
are
long
range,
and
the
health­
based
compliance
alternative
focus
on
short
term
exposure
from
facilities
with
tall
stacks
located
in
rural
settings
is
not
sound
public
health
policy.

Response:
In
accordance
with
our
authority
in
section
112
of
the
Clean
Air
Act,
this
rule
is
focused
on
limiting
emissions
of
HAP
rather
than
fine
particulates.
Although
some
HAP
metals
are
contained
in
particulate
matter
and
we
have
adopted
particulate
matter
limitations
to
control
these
HAPs,
the
focus
of
this
NESHAP
is
not
on
the
control
of
fine
PM.
In
accordance
with
other
parts
of
the
Clean
Air
Act,
EPA
and
the
states
are
developing
other
policy
mechanisms
and
regulations
to
address
fine
PM.
Even
if
sources
are
subject
to
the
health­
based
alternatives
for
HAPs
in
this
rule,
these
sources
must
comply
with
all
applicable
requirements
designed
to
meet
fine
particulate
standards.

Additionally,
we
disagree
with
the
second
part
of
this
comment
regarding
transport,

exposure,
and
stack
heights.
First,
the
health­
based
compliance
alternatives
require
sources
to
include
site­
specific
stack
heights
in
their
risk
assessment.
These
stack
heights
are
either
incorporated
directly
into
their
site­
specific
modeling
analyses
or
used
to
calculate
a
weighted
stack
height
value
(
for
a
lookup
table
analysis).
Second,
risks
from
long
term
exposure
to
relevant
HAP
must
be
assessed.
Third,
there
is
no
assumption
that
sources
will
be
located
in
rural
environments.
Rather,
the
level
of
development
surrounding
a
source
can
be
factored
into
the
risk
assessment
on
a
site­
specific
basis
for
a
site­
specific
risk
assessment.
Risk
assessments
based
on
the
lookup
tables
will
use
the
maximum
pollutant
concentration
beyond
the
facility
fence
line
regardless
of
whether
the
site
of
maximum
concentration
is
populated.
Therefore,
the
lookup
table
analysis
is
protective
regardless
of
the
distribution
of
population
surrounding
a
source.
64
Comment:
One
commenter
(
OAR­
2002­
0058­
0683)
suggested
these
health­
based
compliance
alternatives
do
not
address
ecological
risks
to
sensitive
habitats
in
areas
where
few
people
currently
live.

Response:
We
disagree
with
the
commenter.
As
discussed
in
an
earlier
response,

we
have
assembled
a
list
of
HAP
with
significant
potential
to
persist
in
the
environment
and
to
bioaccumulate.
This
list
does
not
include
Mn,
HCl,
or
Cl2
,
which
are
the
only
HAP
relevant
for
the
health­
based
compliance
alternative
under
the
final
rule.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0676,
OAR­
2002­
0058­
0677)
expressed
concern
that
facilities
existing
in
a
state
would
not
reduce
their
HAP
emissions
and
the
cumulative
effect
would
be
a
continuing
air
toxics
burden
on
the
residents
of
the
state.

Response:
Only
facilities
that
meet
the
risk­
based
criteria
are
eligible
for
the
healthbased
alternatives.
Furthermore,
sources
using
the
health­
based
compliance
alternatives
are
still
required
to
meet
an
emission
standard
for
HCl
and
Mn
that
is
implemented
through
parameters
contained
in
Title
V
permit
conditions
under
appendix
A.
This
is
a
health­
based
standard
that
is
designed
to
protect
public
health.

Comment:
One
commenter
(
OAR­
2002­
0058­
0669)
supported
the
health­
based
compliance
alternative
and
stated
these
alternatives
are
essential
to
the
economic
survival
of
the
small
businesses
that
make
up
the
pressure
treated
wood
industry.
The
commenter
added
that
the
requirements
to
install
bag
houses
or
ESPs
are
significant
for
small
units
and
the
commenter
suggested
such
controls
are
unnecessary
at
facilities
located
in
rural
areas.
One
commenter
(
OAR­
2002­
0058­
0668)
supported
the
alternative
to
reduce
the
cost
of
regulatory
controls
on
units
that
can
demonstrate
little
risk
to
the
public
health
or
the
environment.
The
commenter
added
these
health­
based
compliance
alternatives
provide
for
an
efficient
use
of
both
Agency
and
affected
sources
resources,
and
the
commenter
called
for
these
health­
based
compliance
alternatives
to
be
considered
in
all
MACT
rules
and
future
residual
risk
evaluations.

One
commenter
(
OAR­
2002­
0058­
0674)
added
that
without
the
presence
of
tiered
healthbased
compliance
alternative
small
plants
would
be
economically
threatened
if
required
to
meet
the
MACT
standard.
The
commenter
stated
that
affected
sources
should
not
be
required
to
install
controls
if
the
source
does
not
pose
a
threat
to
human
health
or
the
environment.

Several
commenters
(
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­

0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­
2002­
0058­
0698)
added
that
without
65
these
two
tiers,
small
municipal
generators
would
be
required
to
install
expensive
controls
in
return
for
no
health
benefit
or
cease
electricity
production.

Two
commenters
(
OAR­
2002­
0058­
0671,
OAR­
2002­
0058­
0673)
supported
the
flexible
regulatory
structure
of
the
health­
based
compliance
alternative.
One
of
these
commenters
(
OAR­

2002­
0058­
0671)
cited
section
112(
b)(
c)
and
(
d)(
2),
and
concluded
that
Congress
discussed
the
need
for
standards
to
be
both
adaptable
and
feasible
for
the
source
categories.
The
commenters
suggested
the
variability
in
the
affected
source
category
of
this
boiler
and
process
heater
NESHAP
calls
for
a
regulatory
format
that
is
responsive
to
the
diversity
of
its
affected
sources.

Response:
Our
purpose
in
adopting
the
health­
based
compliance
alternatives
was
to
minimize
compliance
costs
for
sources
with
emissions
that
do
not
present
an
appreciable
risk
of
causing
adverse
health
effects.
We
acknowledge
the
commenters'
recognition
of
the
benefits
achieved
by
adopting
the
health­
based
compliance
alternatives
to
reduce
the
compliance
costs
for
small
businesses.
For
many
affected
sources,
the
costs
associated
with
demonstrating
eligibility
for
the
health­
based
compliance
alternatives
will
likely
be
lower
than
the
costs
associated
with
complying
with
the
technology
requirements
of
the
MACT.

This
includes
small
facilities
and
other
facilities
that
have
already
otherwise
installed
pollution
controls.
Successfully
demonstrating
eligibility
for
the
health­
based
compliance
alternative(
s)
will
result
in
cost­
savings
for
smaller
affected
sources
because
these
facilities
will
not
have
to
expend
costs
on
installing
or
upgrading,
operating,
and
maintaining
the
add­
on
emission
controls
needed
to
comply
with
the
MACT
emission
limits.

Comment:
Two
commenters
(
OAR­
2002­
0058­
0671,
OAR­
2002­
0058­
0695)
refuted
claims
that
these
health­
based
compliance
alternatives
are
exemptions,
since
facilities
that
opt
for
the
health­
based
compliance
alternative
must
meet
certain
standards
or
become
subject
to
the
MACT
compliance
requirements.
The
commenters
added
that
these
health­
based
compliance
alternatives
are
real,
enforceable
emission
standards
under
the
law.

Response:
We
agree
with
the
commenter
that
the
health­
based
compliance
alternatives
are
not
exemptions
from
regulation.
The
health­
based
compliance
alternatives
are
alternative
standards
for
threshold
pollutants
based
on
health
considerations,
rather
than
the
technology­
based
MACT
criteria.
Sources
that
demonstrate
they
are
eligible
to
comply
with
the
health­
based
alternatives
must
operate
in
accordance
with
parameters
set
forth
in
their
Title
V
operating
permits
to
ensure
that
their
emissions
of
particular
66
pollutants
remain
at
levels
that
do
not
present
an
appreciable
risk
of
adverse
health
effects.

12.3
Effects
on
Energy
Supplies
Comment:
One
commenter
(
OAR­
2002­
0058­
0681)
requested
EPA
to
consider
the
cumulative
effects
on
energy
supplies,
in
accordance
with
Executive
Order
13211,
if
a
fuel
switch
is
required
to
comply
in
the
event
of
the
removal
of
the
health­
based
compliance
options.
The
commenter
expressed
concern
that
the
removal
of
a
health­
based
compliance
alternative
would
require
some
affected
sources
to
switch
from
coal
to
natural
gas.

Response:
The
health­
based
compliance
alternatives
remain
intact
as
a
result
of
this
reconsideration.
In
accordance
with
Executive
Order
13211,
we
have
determined
that
our
final
action
on
reconsideration
is
not
likely
to
have
a
significant
adverse
effect
on
the
supply,
distribution,
or
use
of
energy.
Further,
we
have
concluded
that
these
final
rule
amendments
are
not
likely
to
have
any
adverse
energy
effects.

12.4
Reference
Values
Comment:
One
commenter
(
OAR­
2002­
0058­
0688)
stated
stakeholders
had
adequate
notice
on
the
RfC
values
and
opportunity
to
comment
on
the
legitimacy
of
the
values.
In
support
of
this
argument,
the
commenter
identified
specific
references
to
the
IRIS
RfC
concentrations
in
both
the
text
and
Table
4
of
the
proposed
rule.

One
commenter
(
OAR­
2002­
0058­
0660)
requested
that
citizens
with
TILT
(
Toxicant
Loss
of
Tolerance)
be
considered
in
the
health­
based
compliance
alternatives
of
this
MACT
standard.
The
commenter
suggested
that
the
current
levels
of
acceptable
injury
allowed
for
in
this
rule
have
never
been
established
to
present
an
`
ample
margin
of
safety'
with
respect
to
this
population
subset.

Response:
We
disagree
with
the
commenters'
request
for
further
consideration
of
special
populations
when
developing
the
health­
based
compliance
alternatives.
The
reference
values,
which
are
used
as
the
basis
for
the
health­
based
compliance
alternatives
set
in
appendix
A
(
both
the
site­
specific
assessment
option
and
the
lookup
table
assessment
option),
are
designed
to
be
protective
of
sensitive
populations.
The
reference
values
have
undergone
scientific
peer
review
and
have
been
determined
to
be
scientifically
appropriate.

Additionally,
we
agree
with
the
commenter
that
the
use
of
these
reference
values
as
a
basis
67
for
establishing
health­
based
alternatives
was
open
to
public
comment
at
the
proposal
of
this
NESHAP
for
this
application.

12.5
Self­
Monitoring
Comment:
One
commenter
(
OAR­
2002­
0058­
0660)
objected
to
industry
self­
monitoring,

stating
such
an
allowance
is
in
direct
conflict
with
EPA's
duty
to
develop
a
rule
that
is
specific
and
enforceable.

Response:
We
contend
that
these
health­
based
compliance
alternatives
are
both
enforceable
and
adequately
specific
to
the
boiler
and
process
heater
source
category.
The
affected
source
is
required
to:
(
1)
conduct
emissions
tests
or
fuel
analysis
as
specified
in
the
rule,
(
2),
perform
a
risk
assessment
as
outlined
in
Appendix
A,
(
3)
demonstrate
that
it
meets
the
criteria
established
by
the
final
rule
(
4)
assume
Federally
enforceable
permit
limits
(
as
described
in
appendix
A
of
subpart
DDDDD
of
40
CFR
part
63)
that
reflect
the
parameters
in
their
risk
assessment,
and
(
5)
maintain
records
to
show
continued
eligibility.

12.6
Other
Petitioner
Issues
Comment:
Several
commenters
(
OAR­
2002­
0058­
0663,
OAR­
2002­
0058­
0680,
OAR­

2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­

2002­
0058­
0697,
OAR­
2002­
0058­
0698,
OAR­
2002­
0058­
0673)
supported
EPA's
decision
not
to
reopen
petitioner
issues
that
were
excluded
from
this
reconsideration.
One
commenter
(
OAR­

2002­
0058­
0680)
added
that
a
disagreement
with
the
result
of
an
analysis
does
not
constitute
that
an
analysis
must
be
reconsidered
and
the
commenter
recognized
that
the
remaining
issues
were
fully
noticed
with
an
appropriate
comment
period
in
the
proposed
rule.

Response:
The
decision
to
include
certain
elements
of
the
petition
brought
about
by
NRDC
and
EIP
was
previously
made
and
discussed
in
the
proposed
rule
and
notice
of
reconsideration.

Comment:
Several
commenters
(
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­

2002­
0058­
0692,
OAR­
2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­
2002­
0058­
0698,
OAR­

2002­
0058­
0673)
supported
the
refusal
on
the
request
to
stay
the
health­
based
limits.
Several
commenters
(
OAR­
2002­
0058­
0675,
OAR­
2002­
0058­
0679,
OAR­
2002­
0058­
0692,
OAR­

2002­
0058­
0696,
OAR­
2002­
0058­
0697,
OAR­
2002­
0058­
0698)
added
that
municipal
entities
68
require
longer
timeframes
and
regulatory
certainty
in
order
to
allocate
public
resources
towards
a
compliance
method.
One
commenter
(
OAR­
2002­
0058­
0673)
stated
that
granting
a
stay
would
cause
harm
to
affected
facilities
by
effectively
mandating
the
use
of
costly
MACT
controls.
The
commenter
referenced
the
Industry
Interveners'
Response
to
Show
Cause
Order
in
NRDC
v.

EPA
and
EPA
papers
which
opposed
the
judicial
stay.

Response:
The
decision
to
refuse
the
request
to
stay
the
health­
based
compliance
option
was
previously
addressed
in
the
notice
of
reconsideration.

12.7
State
Resources
Comment:
Three
commenters
(
OAR­
2002­
0058­
0677,
OAR­
2002­
0058­
0683,
OAR­

2002­
0058­
0694)
expressed
concern
with
the
time
and
labor
required
to
implement
the
healthbased
compliance
alternatives.
One
commenter
(
OAR­
2002­
0058­
0677)
added
that
the
incentive
to
apply
for
the
health­
based
compliance
alternative
would
place
intensive
demands
on
state
permitting
authorities.
Two
commenters
(
OAR­
2002­
0058­
0683,
OAR­
2002­
0058­
0694)
cited
a
lack
of
training
and
expertise
in
risk
assessment
methodologies
and
the
Risk
Assessment
Reference
Library.
One
commenter
(
OAR­
2002­
0058­
0694)
added
that
there
was
a
significant
time
and
effort
involved
in
reviewing
a
site­
specific
assessment
that
is
allowed
to
follow
"
any
scientifically
peer­
reviewed"
method.
Further,
the
commenter
suggested
that
without
more
specific
guidance,
there
is
a
lack
of
basis
for
accepting
or
rejecting
applications
for
the
healthbased
compliance
alternatives.
The
commenter
requested
that
in
light
of
a
lack
of
expertise
or
resources
to
review
the
site
specific
assessments,
these
assessments
should
be
submitted
for
approval
by
US
EPA
with
notification
to
the
state
and
local
permit
authority.

One
commenter
(
OAR­
2002­
0058­
0672)
suggested
the
requirement
to
submit
a
transparent
and
reproducible
format
of
the
Tier
2
risk
assessment
one
year
in
advance
provides
authorities
with
adequate
time
and
information
in
order
to
verify
the
assessment.
The
commenter
suggested
this
timeline
also
allows
facilities
adequate
time
to
change
their
assessments
based
on
any
comments
from
the
reviewing
authority.
The
commenter
cited
the
section
of
the
rule
(
69
FR
55284)
to
support
this
claim.

Response:
We
acknowledge
the
resource
challenges
faced
by
States.
However,

appendix
A
does
not
require
states
to
review
and
approve
assessments
before
a
source
becomes
eligible
for
the
health
based
alternative.
States
have
the
discretion
to
prioritize
69
and
manage
their
resources
in
reviewing
eligibility
demonstrations.
Furthermore,
EPA
will
review
some
assessments
as
part
of
an
audit
program.

12.8
Point
of
Maximum
Impact
Two
commenters
(
OAR­
2002­
0058­
0670,
OAR­
2002­
0058­
0684)
addressed
the
vagueness
of
the
phrase
"
where
people
live."
One
commenter
(
OAR­
2002­
0058­
0670)
requested
to
incorporate
potential
land
use
changes
where
people
could
reasonably
be
expected
to
live
in
the
future
into
the
demonstrations
of
eligibility.
The
commenter
stated
the
rule
language
`
where
people
live'
does
not
account
for
the
individual
most
exposed
(
IME)
in
the
future
for
a
location
that
was
not
residentially
zoned
at
the
time
of
the
risk
assessment.
One
commenter
(
OAR­
2002­

0058­
0684)
suggested
the
wording
"
location
where
people
live"
is
too
vague
and
suggested
replacing
this
language
with
the
"
point
of
maximum
impact
beyond
the
facility's
property
boundary."

Response:
We
agree
that
there
is
a
need
to
clarify
the
wording
of
the
phrase
"
where
people
live"
in
section
5
of
Appendix
A.
To
address
some
of
the
commenters
concerns,
we
are
changing
the
phrase
to
"
where
people
live
or
congregate
(
e.
g.
including
schools
or
daycares)."
We
believe
that
this
is
an
appropriate
approach
given
that,
as
described
in
EPA's
Air
Toxics
Risk
Assessment
Reference
Library,
sources
can
deviate
from
the
default
assumption
that
an
exposed
individual
remains
at
the
location
of
highest
exposure
for
24
hours
per
day,
365
days
per
year.

We
do
not
believe
any
additional
changes
are
needed
in
section
5
of
Appendix
A
to
account
for
future
land
use
changes.
The
final
rule
requires
that
a
source
complying
with
a
health­
based
compliance
alternative
must
resubmit
their
demonstration
of
eligibility
if
process
or
non­
process
parameters
change
in
a
way
that
could
increase
public
health
risk.

Thus,
if
people
have
moved
into
an
area,
or
if
schools
or
day
care
centers
are
constructed,

the
demonstration
of
eligibility
must
be
resubmitted
with
a
new
risk
assessment
that
incorporates
updated
parameters
to
account
for
the
public
health
risk
of
these
new
populations.
This
resubmission
of
the
eligibility
demonstration
is
part
of
the
existing
requirements
of
appendix
A
for
maintaining
continuous
compliance.
If
a
source
is
no
longer
in
compliance
with
the
health­
based
alternative
due
to
changes
in
land
use,
that
source
must
comply
with
the
technology
standards
in
the
MACT.
70
12.9
Fire
Tube
Boilers
Comment:
One
commenter
(
OAR­
2002­
0058­
0694)
expressed
concern
that
the
NESHAP
excludes
any
size
fire
tube
boiler
from
regulation
and
as
a
result,
not
even
the
combined
risk
of
all
boiler
emissions
would
be
considered
during
the
risk
screening.

Response:
We
disagree
that
emissions
from
fire
tube
boilers
are
excluded
from
the
health­
based
compliance
alternatives.
Fire
tube
boilers
are
included
in
the
small
unit
subcategory
and
are
covered
by
the
MACT
rule.
The
commenter
is
correct
that
the
subcategory
of
existing
small
unit
boilers
are
not
required
to
meet
emission
limits.

However,
new
solid
fuel
small
units
are
required
to
meet
an
emission
limit
of
0.0003
lb/
mmBtu
for
TSM
or
0.025
lb/
mmBtu
for
PM.
Because
fire
tube
boilers
are
part
of
the
affected
source
category
under
subpart
DDDDD,
the
emissions
from
fire
tube
boilers
must
be
included
in
the
risk
assessment
in
order
to
determine
eligibility
with
the
health­
based
compliance
alternatives
in
appendix
A.

12.10
Test
Plans
Comment:
One
commenter
(
OAR­
2002­
0058­
0694)
requested
that
facilities
opting
to
comply
with
the
health­
based
alternative
be
required
to
submit
a
stack
test
plan
prior
to
conducting
HAP
emissions
tests.

Response:
Since
the
health­
based
compliance
alternatives
are
a
component
of
the
rule,
all
testing
and
reporting
requirements
listed
in
the
rule
are
applicable
when
demonstrating
eligibility
for
these
alternatives.
Thus,
a
source
planning
to
demonstrate
eligibility
with
the
health­
based
compliance
alternatives
is
required
to
develop
a
sitespecific
test
plan
as
required
by
section
63.7520(
a)
of
the
rule.
If
a
source
elects
to
conduct
fuel
analysis
as
part
of
the
eligibility
demonstration,
then
the
source
must
develop
and
submit
a
site­
specific
fuel
analysis
plan
as
required
by
section
63.7521(
b)
of
the
rule.