Document ID: EPA-HQ-OAR-2002-0058-0735
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-12-05T05:00Z

OAR-2002-0058

National Emission Standards for Hazardous Air Pollutants for Industrial,
Commercial, and Institutional Boilers and Process Heaters

Summary of Public Comments and Responses 

To GE Petition and Reconsideration of the Final Rule

 

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Sector Policies and Programs Division

Research Triangle Park, North Carolina 27711

November 29, 2006

	Disclaimer

This report has been reviewed by the Sector Policies and Programs
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.

TABLE OF CONTENTS

Chapter                          	Page 

  TOC \o "1-2" \h \z \u    HYPERLINK \l "_Toc125184646"  Chapter 1:
Background Information	  PAGEREF _Toc125184646 \h  1  

  HYPERLINK \l "_Toc125184647"  Chapter 2: Public Comments Received	 
PAGEREF _Toc125184647 \h  2  

  HYPERLINK \l "_Toc125184648"  Chapter 3: Applicability of Emissions
Averaging	  PAGEREF _Toc125184648 \h  4  

  HYPERLINK \l "_Toc125184649"  Chapter 4: Compliance Testing	  PAGEREF
_Toc125184649 \h  6  

  HYPERLINK \l "_Toc125184650"  Chapter 5: Common Stack	  PAGEREF
_Toc125184650 \h  8  

  HYPERLINK \l "_Toc125184651"  Chapter 6: Definitions	  PAGEREF
_Toc125184651 \h  11  

  HYPERLINK \l "_Toc125184652"  6.1 Common Stack	  PAGEREF _Toc125184652
\h  11  

  HYPERLINK \l "_Toc125184653"  6.2 Hybrid Boilers	  PAGEREF
_Toc125184653 \h  11  

  HYPERLINK \l "_Toc125184654"  6.3 Large gaseous fuel subcategory	 
PAGEREF _Toc125184654 \h  13  

  HYPERLINK \l "_Toc125184654"  6.4 Small gaseous fuel subcategory	 
PAGEREF _Toc125184654 \h  13  

  HYPERLINK \l "_Toc125184655"  6.5 Limited use boiler	  PAGEREF
_Toc125184655 \h  14  

  HYPERLINK \l "_Toc125184656"  Chapter 7: Opacity Monitoring	  PAGEREF
_Toc125184656 \h  15  

  HYPERLINK \l "_Toc125184657"  Chapter 8: Proposed Corrections	 
PAGEREF _Toc125184657 \h  17  

  HYPERLINK \l "_Toc125184658"  8.1 Applicability of Units Less Than or
Equal to 25 MWe	  PAGEREF _Toc125184658 \h  17  

  HYPERLINK \l "_Toc125184659"  8.2 Testing Methods	19 

  HYPERLINK \l "_Toc125184660"  Chapter 9: Rule Language Corrections –
63.7522	  PAGEREF _Toc125184660 \h  22  

  HYPERLINK \l "_Toc125184661"  Chapter 10:  Miscellaneous	  PAGEREF
_Toc125184661 \h  24  

 

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 a petition for reconsideration pursuant
to section 307(d)(7)(B) of the CAA from General Electric (GE).  

On April 27, 2005, EPA sent a letter to GE notifying the party of the
intent to grant their petition for reconsideration.  On October 31,
2005, EPA published a Federal Register notice granting reconsideration
and soliciting comments on the proposed amendment to 40 CFR 63.7522 that
would clarify the emissions averaging provision and allow consolidated
testing of commonly vented boilers.

Seventeen public submissions were received from a wide variety of
sources, consisting mainly of government agencies, 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.

Chapter 2

Public Comments Received

The EPA received a total of 17 public 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 10 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) 

(Public Comments and Responses To GE Petition and Reconsideration of the
Final Rule)

Docket No.	Commenter’s Name and Addressa

OAR-2002-0058-0708	R.W. Bollenbecker

OAR-2002-0058-0709	John E. Pinkerton, Vice President, Air Quality,
National Council For Air And Stream Improvement, Inc. (NCASI) 

OAR-2002-0058-0712	Tanja Shonkwiler, Duncan, Weinburg, Genzer &
Pembroke, P.C., Attorney for The Jamestown Board of Public Utilities

OAR-2002-0058-0713	Alphonse McMahon, Risk Management Counsel, General
Electric Company

OAR-2002-0058-0714	Todd Gadawski, Manager, Environmental Safety, The
Medical Center Company (MCCo)

OAR-2002-0058-0715	James P. Witkowski, Air Subcommittee Chair,
Environmental/Technical Committee, The South Carolina Chamber of
Commerce

OAR-2002-0058-0717	Timothy G. Hunt, Senior Director, Air Quality
Programs, American Forest and Paper Association

OAR-2002-0058-0719	Andrew Wallo, Director, Office of Air, Water and
Radiation, Protection Policy and Guidance, U.S. Department of Energy

OAR-2002-0058-0722	Roger H. Brear, Senior Vice President, Paper
Manufacturing and Guy R. Martin, Director, Environment Business
Optimization and Technology, Domtar Industries, Inc.

OAR-2002-0058-0723	Valerie Ughetta, Director of Stationary Sources,
Alliance of Automobile Manufacturers

OAR-2002-0058-0724	Robert D. Bessette, Council of Industrial Boiler
Owners (CIBO)

OAR-2002-0058-0725	Tanja Shonkwiler, Duncan, Weinburg, Genzer &
Pembroke, P.C., Attorney for The Jamestown Board of Public Utilities

OAR-2002-0058-0726	Alphonse McMahon, Risk Management Counsel, General
Electric Company

OAR-2002-0058-0727	Al Yoshizumi, Air Quality Specialist, Dairyland Power
Cooperative

OAR-2002-0058-0728	David P. Novello, LLC on behalf of Laurie L. Zelnio,
Director, Safety, Environment, Standards & E-PDP, Deere & Company

OAR-2002-0058-0730	Raymond C. Ganga, The McBurney Corporation.

OAR-2002-0058-Draft-00xx	Michael Brandon, P.E.  N.C. Division of Air
Quality.

a Commenters listed multiple times due to duplicate comments and
attachments are referred to in Chapters 3 through 10 of this document by
the first number that was assigned to that commenter in the docket. 



Chapter 3

Applicability of Emissions Averaging

	Comment:  Several commenters (OAR-2002-0058-0717, OAR-2002-0058-0724,
OAR-2002-0058-0722, OAR-2002-0058-0715) requested that EPA expand its
emissions averaging option to include common stack configurations with
groups of boilers from different subcategories or units not subject to
the Boiler NESHAP.  Two of these commenters (OAR-2002-0058-0724,
OAR-2002-0058-0722) added that in many situations the layout of boilers
and ductwork to common stacks make it impractical to perform emissions
testing on each individual boiler venting to the common stack due to a
lack of appropriate sampling location and duct work configurations.  One
commenter (OAR-2002-0058-0722) added that in order to test each
individual unit a source would have to build a temporary testing system
of stacks and ductwork to demonstrate initial compliance, and this
temporary system would still not be suitable for demonstrating
continuous compliance.  The commenter contended that without expanding
the testing to groups of boilers from different source categories
venting to a common stack, the NESHAP would require a source to
reconfigure its ductwork and build new stacks.  The commenter did not
believe these reconfigurations were intended by EPA when it drafted this
notice of reconsideration.  

One commenter (OAR-2002-0058-0728) approved of the EPA’s amendments to
allow common stack performance testing under the listed limited
circumstances provided in the notice of reconsideration.

	Response:  We agree with the commenters’ recommendation to extend the
common stack testing option to include large solid fuel units in common
stack configurations with groups of boilers from different
subcategories, when a facility is using the emissions averaging
provision.  We also agree with extending the emissions averaging option
to include common stack configurations that are fed by units subject to
the Boiler NESHAP and by units not subject to the Boiler NESHAP.  

	We consider it appropriate under specified conditions to extend the
emissions averaging option to large solid fuel units at facilities with
stack configurations that contain units from other subcategories (e.g.
gas-fired units) and/or nonaffected units.   EPA has established a clear
and enforceable method, as discussed in Chapter 4, for demonstrating
initial, annual, and continuous compliance when units of different
subcategories and nonaffected units vent to a common stack.  Further,
extending the emissions averaging option to these stack configurations
will not cause adverse effects to human health or the environment.  The
total emissions out of the stack will not increase as a result of this
extension and compliance with the emission limits of each unit feeding
the common stack will be determined by parametric limits on the control
device through which the units vent to the common stack.



Chapter 4

Compliance Testing

	Comment:  Several commenters (OAR-2002-0058-0715, OAR-2002-0058-0717,
OAR-2002-0058-0724, OAR-2002-0058-0722) supported an alternative
methodology to meet the requirements of initial and annual compliance
tests for units opting to use the emissions averaging provision.  These
commenters suggested that during the initial and subsequent annual
compliance tests, all boilers venting to the common stack that are not
subject to emission limits be turned off (i.e. gas-fired units or
non-affected units).  These commenters suggested that shutting down
units of different subcategories or non-affected units would satisfy the
requirements of the boiler NESHAP and they requested that EPA adjust the
language in 63.7522(h) to allow for this type of testing.  One commenter
(OAR-2002-0058-0724) added that these methods will still provide
reliable test data to the regulatory authorities to demonstrate
compliance.  One commenter (OAR-2002-0058-0724) added that since many
large solid fuel units share a stack with gas-fired units, this NESHAP,
as currently proposed, would require individual performance testing on
each large solid fuel boiler, which would greatly increase the costs of
testing compliance, and system downtime.  

	Response:  We agree that turning off units from other subcategories
(i.e. gas-fired units) and/or nonaffected units during the testing
period, satisfies the requirements of the boiler NESHAP emissions
averaging provision.  Allowing the testing of a common stack, when units
from other subcategories and/or nonaffected units are turned off
satisfies the criteria that EPA has generally imposed on the scope and
nature of emissions averaging programs.  These criteria include: (1) No
averaging between different types of pollutants, (2) no averaging
between sources that are not part of the same major source, (3) no
averaging between sources within the same major source that are not
subject to the same NESHAP, and (4) no averaging between existing
sources and new sources.  

We have adjusted the rule language in 63.7522(h) to allow for turning
these units off to demonstrate compliance with the emissions averaging
provision when units belonging to different subcategories of the Boiler
NESHAP vent to the same stack as large solid fuel boilers.	

	Comment: Two commenters (OAR-2002-0058-0724, OAR-2002-0058-0722)
suggested that parametric limits be set on all control devices used on
solid fuel fired units and that these parametric limits be used to
demonstrate continuous compliance with the Boiler NESHAP.  These
commenters added that parametric limits on the control devices for solid
fuel boilers would ensure that these control devices operated under the
conditions established during the initial compliance test and provide a
defensible way to demonstrate continuous compliance with the Boiler
NESHAP.  One commenter (OAR-2002-0058-0722) suggested that parametric
compliance limits be set on any control device in the group of units
sharing a common stack, regardless of whether the conditions are wet or
dry in the stack.

	Response:  We agree that setting parametric limits on all control
devices for solid fuel boilers venting to a common stack is an
acceptable method for demonstrating continuous compliance with the
Boiler NESHAP.  These parametric limits are a clear and enforceable
method of demonstrating compliance .  We have adjusted the rule language
in 63.7541 to allow for a facility to demonstrate continuous compliance
under the emissions averaging provision by using parametric limits on
the control devices of solid fuel-fired units venting to a common stack
with affected units from other subcategories and/or nonaffected units.



Chapter 5

Common Stack

	Comment:  Several commenters (OAR-2002-0058-0727, OAR-2002-0058-0724,
OAR-2002-0058-0728, OAR-2002-0058-0717, OAR-2002-0058-0714) approved of
EPA’s proposed amendments to allow common stack performance testing
for multiple existing, large solid fuel fired boilers vented to a common
stack.  Two commenters (OAR-2002-0058-0717, OAR-2002-0058-0722) added
that in many circumstances it is impractical to require emissions
testing at an individual unit due to ducting and control arrangements
and access points in a group of boilers venting to a common stack.

	Response:  We agree with implementing an emissions averaging approach,
as modified in this final rule to include common stack configurations
with units from other subcategories subject to the Boiler NESHAP.  We
recognize the constraints in locating access points for emissions
testing in many stack configurations, and we believe this provision
provides for sufficient compliance flexibility with the rule.

Comment:  One commenter (OAR-2002-0058-0727) believed that the term
emission point in Appendix A should be considered a common stack or
common duct.  The commenter requested that common stack emissions
testing be allowed for units opting to comply with the Health-Based
Compliance Alternatives in Appendix A.

	Response:  We agree with the commenter that an emission point in
Appendix A can be considered a common stack or common duct.  In order to
demonstrate compliance with  Appendix A, a unit must calculate the
facility’s total maximum hourly emissions of HCl, Cl2, or Manganese
from all appropriate subpart DDDDD units.  Since the applicability
determination is based on total emissions and not the emissions from
each individual subpart DDDDD unit, these emissions can be tested for at
the stack or at each individual unit feeding a common stack, depending
on the facility’s preference outlined in the submission of
eligibility.

	Comment:  One commenter (OAR-2002-0058-0717) requested that the EPA add
language to address common stack configurations outside the context of
the emissions averaging compliance option in section 63.7522.  The
commenter added that units vented to a common stack should be treated as
a single source for the purposes of testing, reporting, and monitoring
even if a source does not opt to use the emissions averaging compliance
option.  

Response:  We agree that units vented to a common stack should be
treated as a single source for the purposes of testing, reporting, and
monitoring for sources choosing to use the emissions averaging provision
but not for sources choosing not to use the emissions averaging
provision.  It was our intent to make the common stack provision an
optional provision for all affected facilities, but limit this provision
for emissions averaging situations.  We intend to add language to
section 63.7522 to indicate that a source ‘may elect’ to use the
emissions averaging provision, to demonstrate compliance for certain
common stack configurations.  However, if the affected facility does not
elect to use the emissions averaging provision, this source is not
eligible to treat the common stack as a single source for purposes of
testing, reporting, and monitoring.

Comment:  One commenter (OAR-2002-0058-0723) agreed with the EPA
approach for treating units vented through a common control device to a
common stack as a single emission point to include with other existing
large solid fuel boilers located at the facility.  However, the
commenter requested that the EPA make no distinction in the approach for
units that vent to a common stack through more than one emissions
control system and for units that vent to a common stack through a
single control system.  The commenter added that in both of these
situations the group of boilers venting to a common stack should be
treated as a single existing solid fuel boiler for the purposes of
subpart DDDDD.  Additionally, the commenter suggested that the testing
and monitoring requirements, and the common average emission rates in
place, guarantee compliance with the requirements in the rule without
the need to require individual units to meet unique operating limits.

	Response:  We disagree with the commenter.  Common stack configurations
where units are vented through individual control devices to a common
stack are fundamentally different than units that vent through a common
control device and then to a common stack.  In the first scenario, it is
imperative that each individual control system can demonstrate
continuous compliance, according to the methods described in Table 8 to
Subpart DDDDD, and therefore this group of units and control devices
venting to a common stack cannot be considered a single unit.  In the
second scenario, if units are vented through a common control device,
there is no need to demonstrate compliance of the control system for
each unit venting to the common control system.  Instead this group of
units is treated as a single unit venting through a single control
device to a single stack.



Chapter 6

Definitions

6.1     Common Stack

	Comment:  One commenter (OAR-2002-0058-0727) recommended that the
definition for the term ‘common stack’ provided in 40 CFR Part 72 be
listed in the definitions provided in 63.7575.

	Response:  We agree with providing this definition of common stack in
the Boiler NESHAP rule.  The definition for common stack referred to by
the commenter from 40 CFR Part 72 is: “the exhaust of emissions from
two or more units through a single flue.”  This is a correct term for
the common stack pertaining to the Boiler NESHAP.  However, we emphasize
that the rule will retain a set of limiting circumstances under which a
group of units venting to a common stack are allowed to test at the
common stack.  We have added a definition to the final rule language
that incorporates this definition.

6.2	Hybrid Boilers

	Comment:  Several commenters (OAR-2002-0058-0729, OAR-2002-0058-0724,
OAR-2002-0058-0717, OAR-2002-0058-0715) requested that EPA modify the
definition for hybrid boilers based on the location of the containment
or steam separation system in the unit in order to clarify the basic
difference between fire tube and water tube units and alleviate
ambiguity when interpreting this rule. Three commenters
(OAR-2002-0058-0724, OAR-2002-0058-0717, OAR-2002-0058-0715) added that
water tube units incorporate a steam drum which provides for steam
separation from water, whereas a fire tube unit uses a containment shell
inside which the water vaporizes and steam separates.  One commenter
(OAR-2002-0058-0729) suggested that a water tube boiler be defined as a
boiler that has a water tube type of steam drum, with no additional heat
exchange surface in the form of fire tubes running through the drum. 
The commenter suggested that a fire tube boiler be defined as any hybrid
type of boiler where steam separation takes place in a vessel that also
contains fire tubes that provide the major heat input to the water.  The
commenter added that this approach will simplify interpretation of this
definition.  

	Response:  We agree with basing the definitions of firetube and
watertube boilers on the location of the steam separation or containment
system in the unit.  We have modified the proposed definitions of both
firetube and watertube units to account for this new basis of
distinction for classifying hybrid boilers into one of these two
categories.

	Comment:  Two commenters (OAR-2002-0058-0724, OAR-2002-0058-0717)
requested that EPA make an addition to the definition of hybrid boiler:
‘All owners or operators of hybrid boilers that have been
registered/certified by the National Board of Boiler and Pressure Vessel
Inspectors and/or the State as firetube boilers as indicated by “FORM
P-2” (manufacturers’ data report for all types of boilers except
watertube and electric As Required by the Provisions of the ASME Code
Rules, Section I) shall be considered small units for the purpose of
this subpart.’

	Response:  We agree with making this addition to the definition of
firetube boiler in the Boiler NESHAP rule.  We consider the ASME Code
Rules and Forms to be an acceptable and established method for
classifying vessel types.  We have modified the definition for hybrid
boilers to allow a facility to classify its hybrid vessel by one of two
methods: (1) the location of the steam separation or containment system,
or (2) the indication of firetube boiler on the ASME P-2 form.

	Comment:  Two commenters (OAR-2002-0058-0724, OAR-2002-0058-0717)
requested that the new definition of hybrid boiler not be retroactive. 
The commenters suggested that this revised definition should apply only
to those units constructed on or after the final promulgation of this
reconsideration.  The commenters added that EPA should consider any
hybrid unit, constructed prior to final promulgation of this
reconsideration, to be a  small unit for the purposes of the boiler
NESHAP.

	Response:  We disagree with the commenters’ suggestion.  The revised
definition of hybrid boilers will apply to all existing units by their
compliance date in 2007.  New or reconstructed units are unaffected by
the changes made to the criteria distinguishing firetube and watertube
units subsequent to January 13, 2003.  New or reconstructed units that
were constructed after the proposal of the Boiler NESHAP are subject to
the applicability criteria at the time the unit commences construction
or reconstruction.  

6.3	Large gaseous fuel subcategory

	Comment:  Two commenters (OAR-2002-0058-0724, OAR-2002-0058-0715)
requested that the definition for large gaseous fuel units be changed to
allow for units to combust oil during periods of natural gas supply
emergencies or natural gas curtailment.  The commenters added that if
the unit combusts oil for periodic testing under these circumstances,
this unit should not be automatically categorized in the large oil fuel
subcategory.

	Response:  We agree that it is necessary for gas-fired units designed
for combusting oil during periods of natural gas curtailment to
periodically tune the unit for proper oil firing and combustion, in the
event of natural gas curtailment.  Based on review of current
regulations in California regarding equipment testing of non-gaseous
fuel, periodic testing of oil will be allowed for a combined total of 48
hours during any calendar year.  This periodic testing will not cause a
boiler to be categorized in the oil fuel subcategories. We will amend
the definitions as appropriate.

Small gaseous fuel subcategory

Comment:  One commenter (OAR-2002-0058-Draft00xx) requested that EPA
modify the current wording of the definition for the small gaseous fuel
subcategory to clarify that it applies to all firetube units, regardless
of size.  The commenter is concerned that the current wording excludes
firetube greater than 10 mmBtu/hr

Response:  Our intent here was to classify all firetube boilers as small
boilers for the purposes of this rulemaking.  We will amend the
definition to clarify that all firetube boilers, regardless or there
size be considered as small units.

6.5	Limited Use Boiler

	Comment:  One commenter (OAR-2002-0058-0723) requested that the EPA
modify the definition of limited use boilers, such that a facility can
take the average of all capacity factors for the limited use units in a
particular subcategory to determine if the average annual capacity
factor of limited use units meets the requirements of less than equal to
10 percent, in order to qualify for the limited use subcategory.  The
commenter added that this modification will allow for operational
flexibility.

	Response:  We did not open up reconsideration of the definition of
limited use boilers in this proposed rule and notice of reconsideration.
 In order to qualify as a limited use boiler, each individual unit must
have a federally enforceable annual average capacity factor of less than
or equal to 10 percent, and we do not intend to change this
requirement.

Chapter 7 

Opacity Monitoring

	Comment:  One commenter (OAR-2002-0058-0719) requested that the EPA
allow for opacity monitoring with a COMS to still occur at a common
stack when a source does not make use of the emissions averaging
provision and opts to do performance testing on individual boilers.  The
commenter added that this regulatory flexibility will reduce compliance
costs and maintain adequate levels of emissions monitoring.  

Two commenters (OAR-2002-0058-0724, OAR-2002-0058-0715) requested that
EPA clarify 63.7525(b) to allow a COMS to be located at the common
stack, regardless of whether the group of boilers sharing a common stack
consists of boilers of different subcategories.  One commenter
(OAR-2002-0058-0724) suggested that it did not believe EPA intended to
require a COMS on individual units sharing a common stack.  The
commenter added that it is impractical, due to a lack of space or
adequate location, to install individual COMS monitors in the duct work
for groups of boilers that share a common stack.  The commenter cites 40
CFR 60, Appendix B, PS-1, to reference that in many cases this
requirement has been satisfied by placing a COMS on the common stack.

	Response:  We agree with these suggestions as long as all units feeding
the common stack are all boilers subject to the NESHAP.  As we discussed
in Chapter 5 in this document, the emissions averaging provision was
intended to be an option for affected facilities to allow for increased
regulatory flexibility.  We reiterate here that if a source chooses to
do performance testing for HAP emissions at each individual unit, the
source is still eligible to locate a COMS monitor on the common stack as
long as all the units feeding the common stack are affected units
subject to the NESHAP.  

We disagree with the commenter’s suggestion to allow for a COMS
monitor to be located at the common stack when groups of boilers from
different affected subcategories are feeding the stack.  We also
disagree with allowing a single COMS unit to be placed on the common
stack if the units feeding the common stack belong to other source
categories.

	Comment:  One commenter (OAR-2002-0058-0713) suggested that language be
added to 63.7522(j)(3) to indicate that a COMS monitor is required at a
common stack, even when each individual boiler unit has a separate
opacity operating limit.  The commenter is concerned that without
additional language, (j)(3) could be misinterpreted to require a COMS in
each duct leading to the common stack.  The commenter noted that
although there is discussion of this intent in the preamble on page 70
FR 62268, the commenter suggested that there be language added to this
effect in the actual rule text.  This same commenter
(OAR-2002-0058-0713) also suggested that language be added to
63.7541(a)(2) to clarify that a single COMS monitor for a group of units
that each vents through a unique control system and then to a common
stack.  The commenter suggested this language is necessary so that this
group of units is treated similarly to a group of units venting through
a common control device to a common stack with respect to the
requirements of a COMS.

	Response:  We agree that there needs to be additional language in the
rule to support our intent of requiring a single COMS monitor on the
common stack when units feeding the common stack are all in the large
solid fuel subcategory.  Although a common stack configuration
consisting of a group of large solid fuel units venting through multiple
individual control devices is not treated as a single unit for the
purposes of the Boiler NESHAP, this stack configuration can be treated
as a single unit for the purposes of the requirements of a COMS.  A
single COMS monitor can be placed on the common stack in this case, as
each unit feeding the stack are subject to the same opacity operating
limit.  We have added language in the final rule to clarify that a
single COMS monitor is required on the common stack for these stack
configurations.

Chapter 8

Proposed Corrections

8.1	Applicability of units Less than or Equal to 25 MWe

	Comment:  One commenter (OAR-2002-0058-0712) disagreed with the
proposed correction to modify 40 CFR 63.4791(c) to exclude “an
electric utility steam generating unit (including a unit covered by 40
CFR part 60, subpart Da and a Mercury (Hg) Budget unit covered by 40 CFR
part 60, subpart HHHH).  The commenter requested that this proposed
correction be removed and that the current definition of units covered
under the Boiler MACT remain unchanged.  Presently, 40 CFR part 60
covers units under 25 MWe (and generators greater than 25 MWe) and the
commenter suggested that 40 CFR part 60, subpart HHHH, in its present
format, is in violation of EPA’s statutory authority, under CAA
Section 112(n)(1).  The commenter noted that both the proposed and final
boiler NESHAP rules covered units under 25 MWe (and generators greater
than 25 MWe).  The commenter added when the utility NESHAP rule was
proposed, the rule specified that boilers less than or equal to 25 MWe
were covered by the Boiler NESHAP.  The commenter disagreed with the EPA
decision, upon reconsideration of the CAMR, to make the applicability of
the CAMR consistent with the Acid Rain and CAIR programs by including
units less than or equal to 25 MWe.  The commenter stated that the
rationale of making the CAMR program consistent with other trading
programs overrides Congress’ intent that boilers less than or equal to
25 MWe not be included in CAMR.  As a result of the previous coverage of
units less than 25 MWe under the Boiler NESHAP, and similar exclusion of
these units under the CAMR, during the rulemaking process, the commenter
suggested that the recent decision to include units with boilers equal
to or less than 25 MWe in CAMR is an arbitrary reversal of EPA’s
historical stance on what units are covered under the Boiler NESHAP.

	Response: The intent of the Boiler NESHAP is to not cover any boiler or
process heater that is covered by another NESHAP.  At the time of
proposal and promulgation of the Boiler NESHAP, we were aware that a
separate NESHAP rulemaking for electric utility boilers was underway. 
When the Boiler NESHAP was promulgated, the rulemaking for electric
utility boilers had not been promulgated and, thus the applicability of
the electric utility rulemaking was not finalized.  Therefore, in the
final rule for the Boiler NESHAP, we included the definition of an
electric utility steam generating unit as listed in section 112 of the
Clean Air Act because a specific CFR subpart for electric utility
boilers could not be cited.  However, upon the promulgation of 40 CFR 60
Subpart HHHH, the Clean Air Mercury Rule, the definition of electric
utility boilers covered under subpart HHHH was clarified to include
boilers serving a generator with a capacity of more than 25 megawatts. 
In this case, 40 CFR 60 Subpart HHHH is the overriding rule determining
the applicability of boilers less than 25 MWe and generators greater
than or equal to 25 MWe.  Our proposed correction was made to exclude
affected source categories that have become subject to 40 CFR 60 Subpart
HHHH since the promulgation of the Boiler NESHAP.  In this case, boilers
less than 25 MWe that are subject to 40 CFR 60 Subpart HHHH are not an
affected source under the Boiler NESHAP.

	Comment: One commenter (OAR-2002-0058-0712) requested that EPA provide
an applicability determination that the commenter is subject to only the
Boiler NESHAP in the alternative that the CAMR is not changed to exclude
units less than 25 MWe and generators greater than 25 MWe.  The
commenter also requested that EPA consider a voluntary opt-into the CAMR
rule for units with boilers less than or equal to 25 MWe and generators
greater than 25 MWe.

	Response:  We cannot grant an applicability determination, as requested
by the commenter.  Since the CAMR is the overriding regulation to the
Boiler NESHAP, the applicability determination will have to be made from
within the CAMR rulemaking process.

8.2	Testing Methods

	Comment:  Three commenters (OAR-2002-0058-0709, OAR-2002-0058-0722,
OAR-2002-0058-0717) requested that the EPA list some specific examples
of equivalent methods in the revised Table 6.  The commenters
specifically added that since the promulgation of the NESHAP, EPA has
received and approved many site-specific requests for the use of these
alternative, ‘equivalent’ methods.  The commenters requested that
these approved methods be added to Table 6.  

One commenter (OAR-2002-0058-0709) provided an attachment of specific
test methods it would like to see added to and retained in Table 6.  The
commenter disagreed with deleting test method ASTM D3684-01 from Table
6.  The commenter added that this test method should be retained in
Table 6, and the final revised table should indicate that this test
method is applicable for determining both arsenic and selenium.  Two
other commenters (OAR-2002-0058-0722, OAR-2002-0058-0717) supported the
additions specified in this attachment.

Two commenters (OAR-2002-0058-0724, OAR-2002-0058-0715) requested that
in addition to the proposed testing methods, the latest revisions of
following test methods be listed in Table 6:  ASTM D3684 for coal
mercury analysis, ASTM D3683 for coal total selected metals, and ASTM
D4208 for coal chlorine content.  These commenters added that these
methods have a long history as established standard methods, and by
adding these methods to Table 6 sources or testing companies would not
have to petition for approval of these established methods.  These
commenters also added that many coal chlorine levels exceed the upper
bound (1136 ppm) on the concentration range for repeatability and
reproducibility on the proposed ASTM D6721, and that ASTM D4208 is a
more appropriate testing method on coals with high chlorine
concentrations.  

Two commenters (OAR-2002-0058-0717, OAR-2002-0058-0722) recommended that
the EPA provide authority to the states for approving equivalent testing
methods that have already been accepted by EPA on multiple similar
site-specific requests.  The commenters added that providing authority
to the states is an efficient way to determine approved ‘equivalent’
testing methods.

Response:  With this action, we have clarified the definition of
equivalent method.  Equivalent methods are voluntary consensus standards
(VCS) or EPA methods which are applicable to the fuel type or target
analyte being measured.  Although we disagree with adding a complete
list of equivalent methods already approved to the rule itself, we have
provided discussion on a list of these previously approved methods in
the preamble to the final rule.  We have also added a definition of VCS
to the rule to help clarify what equivalent methods are.  Equivalent
methods may be used in lieu of the prescribed methods in Table 6 at the
discretion of the source owner or operator.  Therefore, publishing a
list of or adding to the list of “approved methods” is not
necessary.  Similarly, state or EPA approval of equivalent methods is
not necessary.  

	Comment:  Two commenters (OAR-2002-0058-0717, OAR-2002-0058-0722)
requested that the EPA clarify that the approval of an ‘equivalent’
testing method will occur when the site-specific fuel analysis plans are
approved.  The commenters added that this clarification is necessary to
assure facilities that their ‘equivalent’ method is not challenged
after the fact.

	Response:  With this action, we have clarified the definition of
equivalent method.  Equivalent methods are VCS or EPA methods which are
applicable to the fuel type or target analyte being measured. 
Equivalent methods may be used in lieu of the prescribed methods in
Table 6 at the discretion of the source owner or operator.  The source
owner or operator would include the equivalent methods in the test plan
in the same way that they would list the methods listed in Table 6.

	Comment:  One commenter (OAR-2002-0058-0724) requested that the
provision ‘or equivalent’ remain in Table 6 so that future
alterative methods can be utilized as appropriate.

	Response:  We agree with including the provision ‘or equivalent’ in
Table 6, and we have included this provision in the final rule.

	Comment:  One commenter (OAR-2002-0058-0724) suggested that many
testing labs to not have the equipment to conduct the new proposed
tests: ASTM D6722 for mercury in coal; ASTM D6357 for total selected
metals; and ASTM D6721 for chlorine in coal.  The commenter suggested
that requiring new tests in light of scarce equipment would cause
increased testing costs and could eliminate the use of many testing
labs.

Response: We disagree with the commenter.  It is a routine process that
testing methods become outdated and replaced by newer methods.  Testing
labs have adjusted to the changing testing requirements over the years,
in order to remain up-to-date, and we do not expect these revised
methods to be any different However, sources have the ability to
substitute a more viable test method in lieu of the Table 6 methods
under the “or equivalent” modification to the rule.



Chapter 9

Rule Language Corrections – 63.7522

	Comment:  One commenter (OAR-2002-0058-0713) suggested that the term
‘weighted average’ at the start of 63.7522(d) be removed because the
continuous compliance is calculated as a 12-month rolling average, not a
weighted average, after 12 monthly emission rates have been recorded.

	Response:  We agree with the commenter’s suggestion and we have
removed the term ‘weighted average’ from the start of 63.7522(d).

	Comment:  One commenter (OAR-2002-0058-0713) suggested that the term
‘12-month rolling average’ be replaced with ‘monthly’ because
63.7522(f)(1) and (f)(2) address a monthly emission rate, not a 12-month
rolling average.  The commenter added that the variable definition for
AveWeightedEmissions in Equation 3 and Equation 4 be changed from
‘12-month rolling’ to ‘monthly’ because these equations do not
calculate a rolling average.

	Response:  We agree the commenter’s suggestion to modify the rule
language to reflect our intended terminology.  The commenter is
technically correct that Equations 3 and 4 and the corresponding text in
(f)(1) and (2) calculate a monthly emission rate.

	Comment:  One commenter (OAR-2002-0058-0713) suggested that the first
sentence in 63.7522(f) be revised to incorporate the new (f)(3)
paragraph.

	Response:  We agree with the commenter on the language revision and we
have incorporated this oversight in the final rule.

	Comment:  One commenter (OAR-2002-0058-0713) suggested that term
‘emission limit’ be replaced with ‘emission rate’ in
63.7522(f)(1) and (2) because (f)(1) and (2) calculate a rate, whereas
the limit is contained in Table 1.  

	Response:  We agree the commenter and have made these language changes
to the final rule.  Table 1 does contain the emission limits to the
Boiler NESHAP, whereas the statements in (f)(1) and (2) lay out the
process for calculating an actual emission rate which must be compared
to the limit listed in Table 1.

Comment:  One commenter (OAR-2002-0058-0713) suggested that
63.7522(f)(3) clarify that the monthly emission rates refer to the
average weighted emission rates calculated by (f)(1) or (2).  The
commenter added that the phrase ‘as a weighted average’ be removed
from (f)(3) because Equation 4A calculates a rolling average, not a
rolling average as a weighted average.  

	Response:  We agree with the commenter’s suggestion to modify the
rule language, and we have removed the phrase ‘as a weighted
average’ from (f)(3).

	Comment:  One commenter (OAR-2002-0058-0713) suggested that variable
definition for ERi be changed from ‘monthly emission rate’ to
‘monthly weighted average’.  The commenter added that EPA should
clarify this definition by indicating that ERi is calculated by (f)(1)
or (2).

	Response:  We agree with the commenter’s suggestion to modify the
rule language to use the correct terminology in defining the term ERi,
and we have made this change in the final rule.



Chapter 10

Miscellaneous

	Comment:  One commenter (OAR-2002-0058-0724) suggested that the failure
to ensure compliance flexibility with the common stack emissions
averaging option, and the analytical costs associated with this option,
may qualify the proposed amendments as a significant regulatory action
under Executive Order 12866.

	Response:  We disagree with the commenter.  The common stack emissions
averaging option was already determined to be a method for providing
compliance flexibility.  The emissions averaging provision is an option
that some facilities may use to comply with the rule.  Any changes that
result as part of this reconsideration, do not increase the current
analytical costs associated with rule.

	Comment:  One commenter (OAR-2002-0058-0713) had several grammatical
and punctuation corrections for the regulatory text in sections 63.7541
and 63.7522.

	Response:  We have identified and corrected the grammatical corrections
cited by the commenter in these sections of the final rule.

	Comment:  Three commenters (OAR-2002-0058-0719, OAR-2002-0058-0724,
OAR-2002-0058-0715) noted that the February 2004 guidance for National
Stack Testing provided in the preamble at 70 FR 62268 has been replaced
by the final guidance issued on September 30, 2005.  The commenters
suggested that the final rule reference the final guidance document, as
opposed to the superseded 2004 guidance document.

	Response:  We agree with changing the reference to the guidance to its
most up-to-date form.  We remind the commenter that a guidance document
is subject to future revisions, and as such we have included an
electronic reference to the EMAD site so that facilities can be directed
to the most up-to-date guidance documents, as opposed to a retired
reference to a document title that will inevitably become outdated as
subsequent guidance documents are released. 

DRAFT-for EPA Internal Review

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