

[Federal Register: December 28, 2005 (Volume 70, Number 248)]
[Rules and Regulations]               
[Page 76917-76935]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28de05-20]                         


[[Page 76917]]

-----------------------------------------------------------------------

Part II





Environmental Protection Agency





-----------------------------------------------------------------------



40 CFR Part 63



National Emission Standards for Hazardous Air Pollutants for 
Industrial, Commercial, and Institutional Boilers and Process Heaters: 
Reconsideration; Final Rule


[[Page 76918]]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[OAR-2002-0058; FRL-8011-5]
RIN 2060-AM97

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule, amendments; notice of final action on 
reconsideration.

-----------------------------------------------------------------------

SUMMARY: EPA is promulgating amendments to the national emission 
standards for hazardous air pollutants (NESHAP) for industrial, 
commercial, and institutional boilers and process heaters which EPA 
promulgated on September 13, 2004. After promulgation of the final rule 
for boilers and process heaters, the Administrator received petitions 
for reconsideration of certain provisions in the final rule. On July 
27, 2005, EPA published a notice of reconsideration and requested 
public comment on certain aspects of the health-based compliance 
alternatives, as outlined in 40 CFR 63.7507 and appendix A to the final 
rule (40 CFR part 63, subpart DDDDD). After evaluating public comment 
on the notice of reconsideration, we are retaining the health-based 
compliance alternatives in the final rule in substantially the same 
form. However, we are making a limited number of amendments to 40 CFR 
63.7507 and appendix A to the final rule to improve and clarify the 
process for demonstrating eligibility to comply with the health-based 
compliance alternatives contained in the final rule.

DATES: The final rule amendments are effective on February 27, 2006.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-OAR-2002-0058. All documents in the docket are listed in on the 
http://www.regulations.gov Web site. Although listed in the index, some 

information is not publicly available, i.e., CBI or other information 
whose disclosure is restricted by statute. Certain other information, 
such as copyrighted materials, is not placed on the Internet and will 
be publicly available only in hard copy form. Publicly available docket 
materials are available either electronically through 
http://www.regulations.gov or in hard copy form at the Air and Radiation 

Docket, Docket ID No. EPA-OAR-2002-0058, EPA/DC, EPA West, Room B102, 
1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is 
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. The telephone number for the Public Reading Room is 
(202) 566-1744, and the telephone number for the Air and Radiation 
Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For information concerning 
applicability and rule determinations, contact your State or local 
representative or appropriate EPA Regional Office representative. For 
information concerning rule development, contact Jim Eddinger, 
Combustion Group, Emission Standards Division (C439-01), U.S. EPA, 
Research Triangle Park, North Carolina 27711, telephone number (919) 
541-5426, fax number (919) 541-5450, e-mail address: 
eddinger.jim@epa.gov.


SUPPLEMENTARY INFORMATION: Regulated Entities. Categories and entities 
potentially regulated by this action include:

--------------------------------------------------------------------------------------------------------------------------------------------------------
             Category                 SIC code       NAICS code                          Examples of potentially regulated entities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Any industry using a boiler or                 24             321  Manufacturers of lumber and wood products.
 process heater in the final rule.             26             322  Pulp and paper mills.
                                               28             325  Chemical manufacturers.
                                               29             324  Petroleum refiners and manufacturers of coal products.
                                               30   316, 326, 339  Manufacturers of rubber and miscellaneous plastic products.
                                               33             331  Steel works, blast furnaces.
                                               34             332  Electroplating, plating, polishing, anodizing, and coloring.
                                               37             336  Manufacturers of motor vehicle parts and accessories.
                                               49             221  Electric, gas, and sanitary services.
                                               80             622  Health services.
                                               82             611  Educational Services.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Worldwide Web (WWW). In addition to being available in the docket, 
an electronic copy of the final rule is also available on the WWW 
through the Technology Transfer Network (TTN). Following signature, a 
copy of the final rule will be posted on the TTN policy and guidance 
page for newly proposed or promulgated rules at the following address: 
http://www.epa.gov/ttn/oarpg. The TTN provides information and 

technology exchange in various areas of air pollution control.
    Judicial Review. Under section 307(b)(1) of the CAA, judicial 
review of the final rule amendments to the NESHAP is available by 
filing a petition for review in the U.S. Court of Appeals for the 
District of Columbia Circuit by February 27, 2006. Only those 
objections that were raised with reasonable specificity during the 
period for public comment may be raised during judicial review. Under 
section 307(b)(2) of the CAA, the requirements that are the subject of 
the final rule amendments may not be challenged later in civil or 
criminal proceedings brought by EPA to enforce these requirements.
    Background Information Document. EPA proposed and provided notice 
of the reconsideration of the NESHAP for industrial, commercial, and 
institutional boilers and process heaters on June 27, 2005 (70 FR 
36907), and received 35 comment letters on the proposal. A memorandum 
``National Emission Standards for Hazardous Air Pollutants for 
Industrial, Commercial, and Institutional Boilers and Process Heaters, 
Summary of Public Comments and Responses to Reconsideration of the 
Final Rule,'' containing EPA's responses to each public comment is 
available in Docket No. OAR-2002-0058.
    Organization of this document: The information presented in this 
preamble is organized as follows:

I. What is the statutory authority for the final rule?
II. Background
III. What revisions were made as a result of the reconsideration?
    A. Adoption of a Weighted Average Stack Height Metric for 
Appendix A to the Final Rule
    B. Correction Regarding Sources That May Demonstrate Eligibility 
for Health-Based Compliance Alternatives
    C. Review of Eligibility Demonstrations by Permitting Agencies
    D. Clarification of Eligibility Criteria
    E. Timeline for New or Reconstructed Sources To Submit 
Preliminary Submission of Eligibility

[[Page 76919]]

    F. Requirement for Title V Permit Conditions
    G. Health-Based Alternative for Manganese Emissions and Total 
Selected Metals Standard
IV. What are the responses to significant comments?
    A. Methodology and Criteria for Demonstrating Eligibility for 
the Health-based Compliance Alternatives
    B. Tiered Risk Assessment Methodology
    C. Look-up Tables
    D. Site-Specific Risk Assessment
    E. Background Concentrations and Emissions From Other Sources
    F. Health-Based Compliance Alternative for Metals
    G. Deadline for Submission of Health-Based Applicability 
Determinations
    H. Proposed Corrections to the Health-Based Compliance 
Alternatives
    I. Review of Eligibility Demonstrations and Relationship With 
Title V
    J. Miscellaneous
V. Impacts of the Final Rule
VI. Statutory and Executive Order (EO) Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act
    J. Congressional Review Act

I. What is the statutory authority for the final rule?

    Section 112 of the Clean Air Act (CAA) requires EPA to list 
categories and subcategories of major sources and area sources of 
hazardous air pollutants (HAP) and to establish NESHAP for the listed 
source categories and subcategories. Industrial, commercial and 
institutional boilers (ICI), and process heaters were listed on July 
16, 1992 (57 FR 31576). Major sources of HAP are those that have the 
potential to emit greater than 10 tons per year (tpy) of any one HAP or 
25 tpy of any combination of HAP.

II. Background

    On September 13, 2004 (69 FR 55218), we promulgated the NESHAP for 
ICI boilers and process heaters pursuant to section 112 of the CAA. 
Under section 112(d) of the CAA, the NESHAP must reflect the maximum 
degree of reduction in emissions of HAP that is achievable, taking into 
consideration the cost of achieving the emissions reductions, any non-
air quality health and environmental impacts, and energy requirements. 
This level of control is commonly referred to as maximum achievable 
control technology (MACT). However, section 112(d)(4) of the CAA also 
states that ``[w]ith respect to pollutants for which a health threshold 
has been established, the Administrator may consider such threshold 
level, with an ample margin of safety, when establishing emissions 
standards under this subsection.''
    We proposed standards for ICI boilers and process heaters on 
January 13, 2003 (68 FR 16660). The preamble for the proposed rule 
described the rationale for the proposed rule and solicited public 
comments. We requested comment on incorporating various risk-based 
approaches (based on section 112(d)(4) and other provisions of the CAA) 
into the final rule to reduce the cost of regulatory controls on those 
facilities that pose little risk to public health and the environment. 
(See 68 FR 1688-1693.) Industry trade associations, owners/operators of 
boilers and process heaters, State regulatory agencies, local 
government agencies, and environmental groups submitted comments on the 
proposed risk-based approaches. We received a total of 218 public 
comment letters on the proposed rule during the comment period. We 
summarized major public comments on the proposed risk-based approaches, 
along with our responses to those comments, in the preamble to the 
final rule (69 FR 55239) and in the comment response memorandum, 
``Response to Public Comments on Proposed Industrial, Commercial, and 
Institutional Boilers and Process Heaters NESHAP (Revised)'' which was 
placed in the docket for the final rule.
    In the final rule, we adopted health-based compliance alternatives 
for the hydrogen chloride (HCl) emission limit and the total selected 
metals (TSM) emission limit, based on our authority under section 
112(d)(4) of the CAA. Affected sources that successfully demonstrate 
that they are eligible for the HCl health-based compliance alternative 
are not required to demonstrate compliance with specific HCl emissions 
limits in table 1 to the final rule, but are still subject to operating 
and monitoring requirements in the final rule (subpart DDDDD of 40 CFR 
part 63). Affected sources that demonstrate eligibility for the health-
based compliance alternative for TSM are still subject to a technology-
based (MACT) TSM emission limit and operating and monitoring 
requirements in the final rule (subpart DDDDD of 40 CFR part 63) except 
that they may demonstrate compliance with this TSM emission limit based 
on the sum of emissions for seven metals, instead of the eight selected 
metals, by excluding manganese emissions.
    The methodology and criteria for affected sources to use in 
demonstrating eligibility for the health-based compliance alternatives 
were promulgated in appendix A to subpart DDDDD of 40 CFR part 63. (See 
69 FR 55282.) Appendix A specifies the process units and pollutants 
that must be included in the eligibility demonstration, the emissions 
testing methods, the criteria for determining if an affected source is 
eligible, the risk assessment methodology (look-up table analysis or 
site-specific risk analysis), the contents of the eligibility 
demonstration, the schedule for submission of the self-certified 
eligibility demonstrations, and the methods for ensuring that an 
affected source remains eligible. For an affected source to be eligible 
for the health-based compliance alternatives, the owner/operator of the 
source must conduct a risk assessment, as described in appendix A to 
the final rule, and submit the risk assessment, also called the 
eligibility demonstration, to the permitting authority along with a 
signed certification that the assessment is an accurate depiction of 
the affected facility. To ensure the source remains eligible, federally 
enforceable limits reflecting the parameters used in the eligibility 
demonstration must be incorporated into its title V permit.
    Following promulgation of the final rule, the Administrator 
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).\1\ 
Under this provision, the Administrator is to initiate reconsideration 
proceedings if the petitioner can show that it was impracticable to 
raise an objection to a rule within the public comment period

[[Page 76920]]

or that the grounds for the objection arose after the public comment 
period.
---------------------------------------------------------------------------

    \1\ In addition to the petitions for reconsideration, two 
petitions for judicial review of the final rule were filed with the 
U.S. Court of Appeals for the District of Columbia by NRDC, Sierra 
Club, and EIP (No. 04-1385, D.C. Cir.) and American Municipal 
Power--Ohio and Ohio cities of Dover, Hamilton, Orrville, 
Painesville, Shelby, and St. Marys (No. 04-1386, D.C. Cir.). The two 
cases have been consolidated. Eleven additional parties have filed 
petitions to intervene: American Home Furnishings Alliance, Council 
of Industrial Boiler Owners, American Forest and Paper Association, 
American Chemistry Council, National Petrochemical and Refiners 
Association, American Petroleum Institute, National Oilseed 
Processors Association, Coke Oven Environmental Task Force, Utility 
Air Regulatory Group, and Alliance of Automobile Manufacturers are 
intervening with regard to the health-based compliance alternatives.
---------------------------------------------------------------------------

    NRDC and EIP initially requested that EPA reconsider seven issues 
reflected in the final rule that they believe could not have been 
practicably addressed during the public comment period. EIP also filed 
a supplement to this petition which raised additional issues for 
reconsideration. Together, NRDC and EIP requested reconsideration of 
the following issues: (1) The adoption of ``no control'' MACT floors 
for certain subcategories and pollutants; (2) establishing risk-based 
alternatives on a plant-by-plant basis; (3) the existence of health 
thresholds for HCl and manganese; (4) consideration of background 
pollution and co-located emission sources; (5) establishing a health-
based compliance alternative for a pollutant (HCl) that serves as a 
surrogate for other inorganic pollutants; (6) promulgating a health-
based compliance alternative that allows low risk sources of manganese 
emissions to comply with the MACT limitations for metals without 
counting manganese; (7) the procedures for demonstrating compliance 
with the health-based alternatives; (8) consideration of emissions 
during periods of startup, shutdown, malfunction and, (9) the cost 
effectiveness of the health-based alternatives. The NRDC and EIP 
petition also requested that EPA stay the effectiveness of the health-
based compliance alternatives pending reconsideration. By letters dated 
January 28, 2005, we informed NRDC and EIP that we intended to grant 
their joint petition for reconsideration.
    On June 27, 2005, we decided to reconsider (70 FR 36907) several of 
the issues raised in the NRDC and EIP petition pertaining to certain 
provisions of the health-based compliance alternatives in appendix A to 
the final rule. We denied the petitioners' request to stay because in 
this case, a stay was not necessary to protect the public health or 
provide a more adequate timeline for compliance planning. We are 
continuing to review the issue raised by GE with respect to the 
emissions averaging provision of the final rule and published proposed 
action on that petition on October 31, 2005 (70 FR 62264).\2\
---------------------------------------------------------------------------

    \2\ GE requested reconsideration of the emissions averaging 
provisions of the final rule to address how this provision might 
apply in the context of emissions units that vent to a single stack.
---------------------------------------------------------------------------

    In the June 27, 2005, notice of reconsideration, we specifically 
solicited comment in the following eight areas: (1) The methodology and 
criteria for demonstrating eligibility for the health-based compliance 
alternatives; (2) the use of a tiered analysis in appendix A to the 
final rule and the application of the principles set forth in the 1994 
National Academy of Sciences report, ``Science and Judgment in Risk 
Assessment'' (in response to the concerns expressed by the petitioners, 
we entered this document into the public docket for review); (3) the 
methodology used to develop the look-up tables including average stack 
heights, the use of conservative assumptions to account for other 
variables such as meteorology, and the derivation of different look-up 
table values based on the distance from the property line; (4) the 
approach for conducting a site-specific risk assessment and the 
criteria set forth in section 7 of appendix A to the final rule; (5) 
the approach for selecting a hazard index (HI) and hazard quotient (HQ) 
applicability cutoff value of 1.0, exclusive of background or co-
located emissions, and the deferral of further consideration of 
background and co-located sources until we assess facility-wide 
emissions of HAP in future residual risk actions; (6) the 
appropriateness of adopting a health-based compliance alternative for 
manganese and using the same TSM emission limit in table 1 to subpart 
DDDDD of 40 CFR part 63 as a limitation for seven metals, while 
excluding manganese from the calculation; (7) whether we should or 
should not extend the deadline for submission of eligibility 
demonstrations in light of this reconsidered action; and (8) proposed 
corrections regarding the scope sources that are able to demonstrate 
eligibility for the health-based compliance alternatives. The responses 
to the significant comments received on these eight areas are discussed 
later in this preamble. A comprehensive response to public comments is 
also available in a document entitled ``National Emission Standards for 
Hazardous Air Pollutants for Industrial, Commercial, and Institutional 
Boilers and Process Heaters, Summary of Public Comments and Responses 
to Reconsideration of the Final Rule,'' which can be found in the 
docket for this action (Docket No. OAR-2002-0058).

III. What revisions were made as a result of the reconsideration?

    We are making a limited number of amendments to 40 CFR 63.7507 and 
appendix A to the final rule to improve and clarify the process for 
demonstrating eligibility to comply with the health-based alternatives 
contained in the final rule. Overall, however, we are retaining the 
health-based compliance alternatives in substantially the same form.

A. Adoption of a Weighted Average Stack Height Metric for Appendix A to 
the Final Rule

    Sections 4 and 6 of appendix A to the final rule have been modified 
to incorporate procedures for calculating a weighted average stack 
height metric for use in a look-up table analysis. Equation 3 was added 
to section 6 to calculate a weighted average stack height for 
determining the maximum allowable HCl-equivalent emission rate in table 
2 to the final rule. Equation 4 was also added to section 6 to 
calculate a weighted average stack height for determining the maximum 
allowable manganese emission rate in table 3 to the final rule.
    The amendments made to incorporate the weighted average stack 
height metric also required conforming modifications to the format of 
equations 1 and 2 of appendix A to the final rule. Equation 1 in 
section 4 of appendix A was amended to clarify the calculation of the 
maximum hourly emissions.

B. Correction Regarding Sources That May Demonstrate Eligibility for 
Health-Based Compliance Alternatives

    We revised the text of 40 CFR 63.7507(a) and the title of appendix 
A to the final rule to clarify that all subpart DDDDD, 40 CFR part 63, 
sources subject to HCl and TSM emission limits may demonstrate 
eligibility for the health-based compliance alternatives, not just 
large solid fuel-fired units.

C. Review of Eligibility Demonstrations by Permitting Agencies

    Sections 10 and 11 of appendix A to the final rule have been 
amended to explicitly state that eligibility demonstrations may be 
reviewed by permitting agencies (i.e., EPA or any State, local, or 
tribal agency that has been delegated title V permitting authority) to 
verify that they meet the requirements of appendix A and are 
technically sound. To accommodate this addition and to clarify appendix 
A, we also moved some of the provisions in sections 9 and 10 of 
appendix A to different sections.
    We also amended section 6 of appendix A to the final rule to 
clarify that a look-up table analysis may not be used for the 
eligibility demonstration if the permitting authority determines it is 
not appropriate based on site specific factors. A site specific 
analysis under section 7 of appendix A would be required in these 
circumstances.

[[Page 76921]]

D. Clarification of Eligibility Criteria

    With respect to site-specific compliance demonstration, we revised 
sections 5(c)(2) and (d)(2) of appendix A to the final rule to clarify 
the locations where hazards must be assessed. The phrase ``where people 
live'' has been changed to indicate that hazards must be assessed where 
people live or congregate (e.g., including locations such as schools or 
daycare centers). We also reworded other parts of these two paragraphs 
to better express our original intent.

E. Timeline for New or Reconstructed Sources To Submit Preliminary 
Submission of Eligibility

    We amended section 9(c)(1) of appendix A to the final rule to 
specify when new or reconstructed sources that start up after the 
effective date of subpart DDDDD, 40 CFR part 63, must submit a 
preliminary eligibility demonstration. New or reconstructed sources 
must submit this preliminary eligibility demonstration at the same time 
that the source submits an application for approval of construction or 
reconstruction.

F. Requirement for Title V Permit Conditions

    In conjunction with other revisions to section 10 of appendix A to 
the final rule discussed above, we moved the existing requirement that 
sources submit certain parameters for incorporation into a title V 
permit into section 8 to appendix A to the final rule and clarified 
that the proposed permit conditions must be submitted at the same time 
as the rest of the eligibility demonstration. Section 8, which 
addresses the contents of the eligibility demonstration, is a more 
natural and logical place to include this requirement. We also expanded 
the list of parameters that should be considered for inclusion as 
enforceable permit limits.

G. Health-Based Alternative for Manganese Emissions and Total Selected 
Metals Standard

    We are retaining the health-based compliance alternative to the TSM 
standard for sources that can demonstrate eligibility based on 
emissions of manganese. However, we are modifying the language in 40 
CFR 63.7507(b) and related parts of appendix A to the final rule 
slightly to clarify that eligible sources are subject to two 
alternative requirements--one is the health-based compliance 
alternative for manganese emissions in appendix A and the other is an 
alternative MACT emissions limitations for seven selected metals set 
forth in 40 CFR 63.7507(b).
    With respect to manganese emissions, an eligible source must 
satisfy the requirements of appendix A to the final rule, which include 
the requirement to submit, for incorporation as conditions in the title 
V permit, the parameters that make the affected source eligible for the 
health-based alternative. Compliance with these and other appendix A 
requirements for manganese represents compliance with the health-based 
alternative for these manganese emissions.
    However, the remaining seven metals that are covered by the 
technology-based TSM standard must continue to meet a technology-based 
standard based on MACT. Thus, we are retaining the existing requirement 
that eligible sources comply with the TSM limit in table 1 to the final 
rule based on the sum of seven metals rather than eight. Using the same 
methodology we used to develop the TSM MACT limitation for eight 
metals, we derived an alternative MACT limitation for seven metals for 
the final rule promulgated on September 13, 2004. This alternative 
applies only to those sources that demonstrate eligibility for the 
health-based alternative for manganese emissions. Because our MACT 
methodology yielded the same MACT standard for both seven and eight 
metals, we expressed the alternative MACT standard for seven metals as 
a requirement to comply with the standard in table 1 based on the sum 
of seven metals instead of repeating the numerical standard in 40 CFR 
63.7507(b).
    We explain our basis for these revisions further below in response 
to individual comments.

IV. What are the responses to significant comments?

    We received 35 public comment letters on the proposed rule and 
notice of reconsideration. Complete summaries of all the comments and 
EPA responses are found in the Response-to-Comments document (see 
SUPPLEMENTARY INFORMATION section). The most significant comments are 
summarized below.

A. Methodology and Criteria for Demonstrating Eligibility for the 
Health-Based Compliance Alternatives

    Comment: Two commenters suggested that EPA provide for flexibility 
and engineering judgment by allowing an applicability cutoff HI or HQ 
of greater than 1.0 in individual situations. One commenter stated that 
a value of 1.0 is the most stringent margin of safety required and the 
Agency could use a HI greater than 1.0 in certain cases. The commenter 
added that no additional margin of safety is required because the 
Reference Concentration (RfC) calculation contains many layers of 
protection, including safety factors to account for uncertainty.
    One commenter 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 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 non-cancer effects during 
a lifetime. An HI or HQ less than or equal to 1.0 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 in this 
rule, using an HI and HQ of 1.0 as a health-protective default is 
appropriate and, along with the risk assessment methods specified in 
appendix A to the final rule, protects public health with an ample 
margin of safety as required by CAA section 112(d)(4).
    Comment: One commenter 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 health-based 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 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

[[Page 76922]]

the equivalent amount of HCl formed in the atmospheric reactions.
    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 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-protective default is appropriate 
and helps protect public health with an ample margin of safety.
    Additionally, as stated above, we believe that it is appropriate to 
apply our risk assessment methodology to the health-based alternative 
compliance options in the final 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 to 
the final rule, helps ensure that public health is protected with an 
ample margin of safety.

B. Tiered Risk Assessment Methodology

    Comment: Multiple commenters supported the flexibility and 
efficiency of a tiered risk assessment methodology, and these 
commenters stated that the methodology set forth in appendix A to the 
final rule provided an appropriate balance of conservatism and accuracy 
to protect the public health with an ample margin of safety. One 
commenter 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. Other commenters 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.
    Response: We agree with the flexible, efficient, and health-
protective nature of a two-tiered risk approach. 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 CAA section 112.

C. Look-up Tables

    Comment: Several commenters disagreed with use of the look-up 
tables because they believe there is 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 the reconsideration, the look-up tables should 
not be used when unique site-specific factors such as building 
downwash, rain caps, or complex terrain occur, because these factors 
are not accounted for in the look-up tables. One commenter 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 with the health-based compliance 
alternative.
    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.
    Comment: Three commenters suggested alternatives to the average 
stack height metric. One commenter proposed an alternate method of four 
stack height ranges which is currently used in the State's hazardous 
air pollutant rule. Two commenters requested EPA to consider weighted 
stack heights and cited the use of a weighted stack height metric in 
the proposed amendments to the plywood NESHAP. The commenters suggested 
the weighted stack height more accurately portrays the potential risk 
than the average stack height metric.
    Four commenters expressed concern with the appropriateness and 
accuracy of using the average stack height metric in the look-up 
tables. Three of these commenters suggested limiting the use of the 
look-up tables to facilities with similar stack heights to those 
assumed in the model.
    One commenter 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 the final 
rulemaking, including this action, which supports the development of 
the average stack height metric that would enable a member of the 
public to evaluate EPA's methodology.
    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

[[Page 76923]]

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 to the final rule, 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 amendments to the plywood NESHAP (70 FR 44021).
    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 to the final rule, is more health 
protective when most emissions are from the shortest stacks. Further, 
using this more precise method does not undercut our reliance on 
health-protective assumptions in the look-up table analysis when most 
of the emissions come from taller stacks.
    Comment: Several commenters suggested that the use of the minimum 
distance to property boundary metric is overly conservative. Two 
commenters requested EPA to allow a weighted average for the distance 
to property boundary when there are multiple emission units. These two 
commenters argued that this metric would portray more accurate 
estimates of the potential risk from facilities.
    One commenter 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. The commenter 
expressed concern that the current use of minimum property distance may 
not be the point of maximum impact.
    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 look-up 
tables and do not believe that it is appropriate to change this metric 
towards one that would be uniformly less health-protective.
    It is incorrect to assert that, when performing a look-up table 
analysis, the minimum distance to the property boundary may not be the 
point of maximum impact. For the look-up tables, we developed the 
allowable emission rate for each property boundary distance from the 
maximum modeled HAP concentrations beyond that property boundary. 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.

D. Site-Specific Risk Assessment

    Comment: Several commenters disagreed with the level of guidance 
EPA provided for conducting a site-specific assessment. Three of these 
commenters 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 1-year exposure instead of the 
traditional lifetime exposure. One commenter 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 the final 
rule does not provide specific, knowable, replicable, and enforceable 
legal standards necessary to govern and enforce the final rule. 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.
    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. In section 7(c) of 
appendix A to the final rule, EPA has established specific minimum 
criteria for site-specific compliance demonstrations. In order to 
demonstrate eligibility for the health-based 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 site-specific, 
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 States 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 requirements in 
section 7(c) of appendix A to the final rule 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 ATRA Reference 
Library. However, we do not feel that it is necessary to require this 
prior approval.

E. Background Concentrations and Emissions From Other Sources

    Comment: Multiple commenters 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 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.

[[Page 76924]]

    Several of the commenters that opposed consideration of emissions 
from background or co-located sources argued that the statutory 
language in CAA section 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 added that background or co-
located emissions do not fall into a source category or subcategory of 
major sources listed for regulation. Two commenters 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.
    Three commenters cited a 1990 Senate Report, and concluded that the 
consideration of background or co-located emission sources would be the 
kind of lengthy study Congress intended to avoid. Two commenters 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 
co-located emission sources when evaluating whether or not a facility 
qualifies for the health-based alternative standard in appendix A to 
the final rule.
    One commenter 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 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 added that 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 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 disagreed with the health-based 
compliance alternative for metals because it does not adjust for 
facility-wide emissions
    Three commenters 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 excluding background or co-located emissions 
ignore cumulative risk and do not protect the public health.
    One commenter contended that the tiered risk approach used at this 
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 
MACT 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 co-located emission sources.
    Response: Based on the arguments made by several commenters and our 
review of the CAA, we believe it is permissible under CAA section 
112(d) 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 section 
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 ICI boilers and process heaters. 
Although we may combine several source categories into one NESHAP 
rulemaking as we did in this action, we do not construe the CAA to 
require that we regulate the emissions from all other source categories 
through an individual section 112(d) rule for particular source 
categories.
    The focus of section 112(d) of the CAA is on establishing emission 
standards for individual source categories. Section 112(d)(1) indicates 
that the administrator is to ``promulgate regulations establishing 
emission 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 
schedule provided in subsections (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 CAA 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 CAA to require 
that we consider emissions from other source 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 rulemaking.
    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 CAA 
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.

    This statement suggests an intent for EPA to address only whether 
``sources in the category'' present a risk to public health when EPA is 
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, we believe it is permissible to conclude that the facility-
wide impact is not the focus of the analysis in the development of a 
CAA section 112(d) rule. Under our interpretation, the appropriate 
analysis under the CAA 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 of 
40 CFR part 63, a source must demonstrate

[[Page 76925]]

eligibility based on the emissions from all units in the ICI boilers 
and process heaters source category. Because all emissions units in the 
category are covered, any background emissions or 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 CAA 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 alternative 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 a health-based emissions limitation or must meet a technology-
based emissions limitation.
    Although a particular facility may be identified as a major source 
of HAP for purposes of CAA 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 NESHAP 
rulemaking promulgated under section 112(d). The sources covered by 
these NESHAP rules are not eligible to comply with the health-based 
alternatives in the ICI boilers and process heaters NESHAP because an 
ICI boiler or process heater at the same site is eligible for the 
health-based alternative in the NESHAP for ICI boilers and process 
heaters.
    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 manganese, and only if emissions of these HAP 
meet the health-based criteria defined in appendix A to the final rule. 
Affected sources that can comply with the health-based 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 CAA 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 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 (70 FR 19997), we may consider co-
located sources and background levels where appropriate.
    Comment: Three commenters agreed with the Agency suggestion to 
revisit the consideration of background emission during future residual 
risk evaluations. However, one commenter disagreed with the suggestion 
to revisit facility-wide residual risk determinations in future 
residual risk rules and stated that 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 expressed concern on considering co-located 
emissions only during the residual risk analysis. One commenter stated 
that deferring the risk screening acts is contrary to the intent of the 
CAA. Three commenters were not satisfied with the residual risk 
evaluations performed to date. Two commenters specifically cited that 
background concentrations for benzene or any other HAP were not 
incorporated into the Coke Oven Residual Risk report. One commenter 
added that 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 risk rulemaking stage under section 112(f) of the CAA. As 
noted above, we do not construe the requirement in CAA section 
112(d)(4) to ``consider such threshold, with an ample margin of safety, 
when establishing emission standards'' under CAA 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 rule 
development. However, as stated in our recent residual risk rule for 
coke ovens, we do not agree that CAA 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. (70 FR 19992, 19998; April 15, 2005) 
Section 112(f) of the CAA 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 CAA 
sections 112(d)(4) and 112(f), the context surrounding the phrase is 
different in each section. The context of CAA subsection 112(d) focuses 
on each individual source category for which we are promulgating a 
NESHAP rulemaking under CAA subsection (d). Although we agree that the 
first stage of our section 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 CAA subsection (f) and in 
evaluating ``other relevant factors'' under this subsection. (70 FR 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 health-based alternative under section 112(d)(4) of 
the CAA.
    We do not construe section 112(d)(4) of the CAA to accelerate the 
residual risk analysis under CAA 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) 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.

[[Page 76926]]

    Comment: Two commenters felt it was unclear how the health-based 
compliance alternatives will affect CAA section 112(f) residual risk 
evaluations for HCl and manganese, and asked if these two threshold 
pollutants will be exempted from residual risk assessments.
    Response: HCl and manganese will not be exempted in future CAA 
112(f) analyses. Rather, exposure to these two pollutants will be 
assessed along with exposure to other HAP emitted from the source 
category.

F. Health-Based Compliance Alternative for Metals

    Comment: Multiple commenters agreed with EPA's method for 
evaluating manganese and the basis of excluding manganese from the TSM 
emission limit for units that comply with the manganese health-based 
compliance alternative. These commenters also stated that the health-
based compliance alternative adequately protects the public health. One 
commenter cited EPA re-analysis of the MACT floor based on seven 
instead of eight metals, and concluded that because manganese was only 
about 5 percent of the TSM, the MACT floor remained the same.
    Several commenters disagreed with the appropriateness and 
lawfulness of the manganese health-based compliance alternative. Three 
commenters stated that EPA has not provided a justifiable explanation 
for the exclusion of manganese from the calculation of TSM. The 
commenters contended that although EPA found the MACT floor to be the 
same whether or not manganese was included in the floor analysis, this 
reasoning does not justify removing manganese from the TSM limit. One 
commenter stated the mechanism through which the manganese compliance 
alternative operates unlawfully allows plants with low manganese 
emissions to avoid controlling the emissions of other non-mercury 
metals. Further, the commenter suggested that the top-performing 
sources used to calculate the MACT floor may have low manganese 
emissions because existing controls at the source may reduce manganese 
emissions, such that the TSM emission limit would not be affected by 
the incorporation of manganese concentrations. The commenter emphasized 
that dirtier sources would also be allowed to exclude manganese from 
their TSM limit calculations and as a result be allowed to emit higher 
levels of manganese 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 40 CFR 63.7507(b) subpart DDDDD, 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 limit. 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 40 CFR 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 to the final rule.
    The methodology for the MACT floor analysis conducted for 
establishing this 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 seven metals, we performed the same MACT floor 
analysis that we conducted for the TSM emission limit for eight 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 pound per million British thermal units (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 to the final rule in 40 CFR 63.7507(b), we expressed the 
alternative, technology-based TSM limit for these seven 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 eight metals was the same as the unit 
selected under the analysis for seven 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 
sources 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.
    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 
particulate matter (PM) emissions to require control under the PM 
provision of the final rule. In these cases, we did not think that PM 
would be an appropriate surrogate for metallic HAP. Under the rules in 
subpart DDDDD of 40 CFR part 63, 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 final rule, the TSM emission limit 
would minimize the impacts on small entities (e.g., furniture industry, 
sugar cane industry) since

[[Page 76927]]

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/mmBtu, 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/mmBtu) 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 eight metals. Fuel analyses from six 
coal-fired facilities indicate that even if a coal-fired facility could 
demonstrate eligibility with the TSM health-based compliance 
alternative and may exclude manganese emissions, it would still require 
high 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 principal metal in biomass while manganese only makes 
up a small fraction of the metals contained in coal.
    Comment: One commenter stated that EPA cannot adopt risk-based 
exemptions for pollutants for which no health threshold has been 
established. The commenter contended, based on documents in EPA's 
Integrated Risk Information System (IRIS), that no health threshold has 
been established for manganese. On the contrary, two commenters 
specified that manganese has long been recognized as a threshold 
pollutant. Another commenter stated that unlike other metals in the 
MACT list, manganese 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) of the CAA 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 
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 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 minimal risk levels received next preference, 
followed by California Environmental Protection Agency (CalEPA) chronic 
reference exposure levels and unit risk estimates. 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 
CAA 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 http://www.epa.gov/iris, but we have 

added the relevant pages in IRIS to the docket for this rulemaking 
action. As listed in table 4 of the preamble to the rule (68 FR 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 lowest observable adverse effect level issue, the 
methodology employed by EPA recognizes that while a no observable 
adverse effect level 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. 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 Web site (http://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 
acute exposure guidelines level (AEGL) value for manganese compounds, 
the table does contain an immediately dangerous to life and health 
(IDLH)/10 value of 50 mg/m3. This is the acute dose-response value that 
we used, as reflected in table 3 (converted to 50000 ug/m3) 
of the screening assessment memorandum (OAR-2002-0058-0608). Thus, the 
commenter's assertion that the table on the Web site contains no acute 
dose-response value or that EPA does not know what that value might be 
is

[[Page 76928]]

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.

G. Deadline for Submission of Health-Based Applicability Determinations

    Comment: Numerous commenters did not deem it as 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.
    Several commenters requested that the Agency consider including an 
extension of at least 1 year to both the submission of eligibility and 
final compliance dates in the final rule. These commenters added that 
the uncertainties resulting from the reconsideration and ongoing 
litigation made the original deadlines impractical.
    One commenter disagreed with extending the submission of 
eligibility demonstration or compliance dates of affected sources under 
any circumstances. The commenter contended that an extension will only 
further delay the installation of the pollution controls that are 
required by the CAA. The commenter added that it is unlawful to extend 
compliance dates of affected sources.
    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 as proposed (70 FR 36913), we did not anticipate that 
significant revisions would be made as a result of the 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 CAA 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 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, 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 the 
reconsideration notice, as proposed, 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 
revisions to the applicability demonstration methodology for the 
health-based alternatives. (70 FR 36910, 36913) Thus, affected sources 
were on notice that significant revisions 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. (7 FR 36910) The time required to 
complete the 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.

H. Proposed Corrections to the Health-Based Compliance Alternatives

    Comment: Three commenters disagreed with the proposed correction to 
extend the risk-based exemptions beyond the large solid-fuel 
subcategory. These commenters believed the expansion of the health-
based compliance alternative to other subcategories to be a significant 
rule change that would require a separate formal rulemaking 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 added that the analysis of TSM contained in the docket was 
specific to large solid fuel units and not all units for which the 
proposed correction seeks to offer applicability. One commenter cited 
sections within the final preamble language that indicated the 
alternatives applied to large solid fuel-fired sources.
    Two commenters contended 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 provided notice 
and opportunity to comment on the proposed revisions to the text of the 
final rule in accordance with the rulemaking requirements of section 
307(d) of the CAA. Commenters have not cited legal authority in the CAA 
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 health-based compliance alternatives is unclear and 
contradictory. EPA included language in 40 CFR 63.7507(a) that limits 
the applicability of the

[[Page 76929]]

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 OAR-2002-0058) 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 40 CFR 63.7507(b) 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 to the final rule 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 the 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 is to remove the words ``for large solid fuel boilers 
located at a single facility'' from 40 CFR 63.7507(a) and the words 
``Specified for the Large Solid Fuel Subcategory'' from the title of 
appendix A to the final rule.
    Because large solid fuel-fired units are not the only units that 
have applicable manganese and HCl MACT limits, we believe it is 
technically correct, and appropriate, to allow all affected sources 
with manganese 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 health-based 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 amendments we are making 
in the final 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 
to the final rule, 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 final rule.
    In the final rule, the cost and economic analyses developed as part 
of the final MACT rule 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 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 showed that the estimated costs of the 
final rule would be lower if the health-based 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 health-based alternatives. Thus, 
this correction to the final rule will not result in a dramatic 
difference in our rough control cost and emissions reduction estimates. 
Since we evaluated the costs of the final rule without the health-based 
compliance alternatives, we have no reason to believe this amendment 
will increase compliance costs above these high-end estimates. The 
analysis we 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 final 
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 in our supplemental analysis of the impact on 
control costs and emissions 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

[[Page 76930]]

complete several Statutory and Executive Order Reviews including: the 
Paperwork Reduction Act, the Regulatory Flexibility Act, and the 
Unfunded Mandates Reform Act of 1995.

I. Review of Eligibility Demonstrations and Relationship With Title V

    Comment: Several commenters pointed out that the health-based 
compliance alternative is dependent on the approval from a permitting 
authority via issuance of a title V permit that includes enforceable 
alternative limits. These commenters stated that the proposed process 
for reviewing and incorporating the health-based compliance 
alternatives into the permits is unworkable because many parameters 
that affect air dispersion modeling and risks are not required to be 
incorporated into the title V permit.
    One commenter requested EPA to clarify in sections 9 and 10 of 
appendix A to the final rule that a facility's compliance with the 
health-based compliance alternatives 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 eligibility 
determination is not approved, the facility must comply with the final 
NESHAP rule requirements.
    One commenter opposed a requirement to obtain EPA or State agency 
approval of the site-specific risk assessments as currently stated in 
the hazardous waste combustion rule (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 final HWC MACT rule and 
recommended not doing so in the final 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 comply with the health-based 
alternative. Thus, under the procedures in appendix A of subpart DDDDD 
of 40 CFR part 63, as amended in this action, a source becomes eligible 
to comply with the health-based alternatives at the time it submits an 
eligibility demonstration meeting the requirements of section 8 of 
appendix A to the final rule.
    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 to the final rule 
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 final rule when promulgated on September 14, 
2004. Subpart DDDDD of 40 CFR part 63 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 the final rule 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 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 40 CFR 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: Several commenters requested that EPA specify additional 
process and non-process related parameters under section 11 of appendix 
A to the final rule to clarify the enforceable requirements for the 
facility. One commenter specifically requested that ``emission rate'' 
be added to the list of parameters. Three commenters requested that 
non-process parameters that can affect air dispersion modeling be 
included, such as stack height, exit gas temperature, distance to the 
plant property line, and changes in RfC or land-use.
    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 to the final rule 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: Three commenters 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 health-based eligibility determination.
    Two commenters stated that the health-based compliance alternative 
will delay compliance with MACT for sources that attempt to 
unsuccessfully demonstrate eligibility with the health-based compliance 
alternatives.

[[Page 76931]]

    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 rule 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 
1-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 to the final rule. We do not necessarily endorse the use of 
CAA section 112(i)(3)(B) to grant compliance date 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.

J. Miscellaneous

    Comment: Two commenters addressed the vagueness of the criteria for 
determining the location at which the affected source must demonstrate 
that the HI for HCl and chlorine (Cl2) and the HQ for 
manganese is less than or equal to 1.0. One commenter 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 that the rule language ``where people live'' does 
not account for the individual most exposed in the future for a 
location that was not residentially zoned at the time of the risk 
assessment. One commenter suggested replacing ``where people live'' 
with the ``point of maximum impact beyond the facility's property 
boundary.''
    Response: We agree that there is a need 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 a 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 
daycare 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 to the final rule 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.

V. Impacts of the Final Rule

    The revisions incorporated as a result of the final rule amendments 
do not change any of the impacts presented in section V of the preamble 
to the final rule which was published at 69 FR 55218 (September 13, 
2004).

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA 
must determine whether the regulatory action is ``significant'' and, 
therefore, subject to review by OMB and the requirements of the 
Executive Order. The Executive Order defines ``significant regulatory 
action'' as one that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or Tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs, or the rights and obligations of 
recipients thereof; or
    (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, it has been 
determined that today's action is a ``significant regulatory action'' 
because it raises novel legal or policy issues. As such, the action was 
submitted to OMB for review under Executive Order 12866. Revisions made 
in response to OMB suggestions or recommendations are documented in the 
public record (see ADDRESSES section of this preamble).

B. Paperwork Reduction Act

    Today's final rule amendments impose no new information collection 
requirements on the industry. Because there is no additional burden on 
the industry as a result of the final rule amendments, the information 
collection request has not been revised. The Office of Management and 
Budget (OMB) has previously approved the information collection 
requirements contained in the existing regulations under the provisions 
of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., and has 
assigned OMB control number 2060-0551 (EPA No. 2028.02). A copy of the 
OMB approved Information Collection Request (ICR) may be obtained from 
Susan Auby, Collection Strategies Division, U.S. Environmental 
Protection Agency (2822T), 1200 Pennsylvania Ave., NW., Washington, DC 
20460 or by calling (202) 566-1672.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An Agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are listed in 40 CFR part 9 and 40 CFR chapter 15.

[[Page 76932]]

C. Regulatory Flexibility Act

    EPA has determined that it is not necessary to prepare a regulatory 
flexibility analysis in connection with today's final rule amendments.
    For purposes of assessing the impacts of today's final rule 
amendments on small entities, a small entity is defined as: (1) A small 
business having no more than 500 to 750 employees, depending on the 
business' NAICS code; (2) a small governmental jurisdiction that is a 
government of a city, county, town, school district or special district 
with a population of less than 50,000; and (3) a small organization 
that is any not-for profit enterprise which is independently owned and 
operated and that is not dominant in its field.
    We conclude that the final rule amendments will not have a 
significant economic impact on a substantial number of small entities. 
This rule will not impose additional regulatory requirements on small 
entities. After evaluating public comment on the notice of 
reconsideration, we are retaining the health-based compliance 
alternatives in the final rule in substantially the same form. However, 
we are making a limited number of amendments to 40 CFR 63.7507 and 
appendix A to the final rule to improve and clarify the process for 
demonstrating eligibility to comply with the health-based compliance 
alternatives contained in the rule.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures by State, local, and tribal governments, in 
the aggregate, or by the private sector, of $100 million or more in any 
1 year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires EPA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost effective, or least-burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective, or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed, 
under section 203 of the UMRA, a small government agency plan. The plan 
must provide for notifying potentially affected small governments, 
enabling officials of affected small governments to have meaningful and 
timely input in the development of EPA's regulatory proposals with 
significant Federal intergovernmental mandates, and informing, 
educating, and advising small governments on compliance with the 
regulatory requirements.
    EPA has determined that today's final rule amendments do not 
contain a Federal mandate that may result in expenditures of $100 
million or more for State, local, and tribal governments, in the 
aggregate, or the private sector in any 1 year. Although the final rule 
have annualized costs estimated to range from $690 to $860 million 
(depending on the number of facilities eventually demonstrating 
eligibility for the health-based compliance alternatives), today's 
final rule amendments do not add new requirements that would increase 
this cost. Thus, today's final rule amendments are not subject to the 
requirements of sections 202 and 205 of the UMRA. In addition, EPA has 
determined that the final rule amendments do not significantly or 
uniquely affect small governments because there are no new requirements 
that apply to such governments or impose obligations upon them. 
Therefore, today's final rule amendments are not subject to section 203 
of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132 (64 FR 43255, August 10, 1999) requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by State and local officials in the development of regulatory 
policies that have federalism implications.'' ``Policies that have 
federalism implications'' are defined in the Executive Order to include 
regulations that have ``substantial direct effects on the States, on 
the relationship between the national government and the States, or on 
the distribution of power and responsibilities among the various levels 
of government.''
    The final rule amendments do not have federalism implications. It 
will not have substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, as specified in Executive Order 13132. None of the affected 
facilities are owned or operated by State governments, and the 
requirements discussed in today's action will not supersede State 
regulations that are more stringent. Thus, Executive Order 13132 does 
not apply to today's final rule amendments.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175 (65 FR 67249, November 9, 2000) requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by tribal officials in the development of regulatory policies 
that have tribal implications.'' ``Policies that have tribal 
implications'' are defined in the Executive Order to include 
regulations that have ``substantial direct effects on one or more 
Indian tribes, on the relationship between the Federal government and 
Indian tribes, or on the distribution of power and responsibilities 
between the Federal government and Indian tribes.'' The final rule 
amendments do not have tribal implications, as specified in Executive 
Order 13175.
    The final rule amendments do not significantly or uniquely affect 
the communities of Indian tribal governments. We do not know of any ICI 
boilers or process heaters owned or operated by Indian tribal 
governments. However, if there are any, the effect of these rules on 
communities of tribal governments would not be unique or 
disproportionate to the effect on other communities. EPA specifically 
solicited additional comment on the final rule from tribal officials, 
but received none. Thus, Executive Order 13175 does not apply to 
today's final rule amendment.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any 
rule that: (1) Is determined to be ``economically significant'' as 
defined under Executive Order 12866, and (2) concerns an environmental 
health or safety risk that we have reason to believe may have a 
disproportionate effect on children.
    If the regulatory action meets both criteria, we must evaluate the 
environmental health or safety effects of the planned rule on children, 
and explain why the planned regulation is preferable to other 
potentially effective

[[Page 76933]]

and reasonably feasible alternatives we considered.
    We interpret Executive Order 13045 as applying only to those 
regulatory actions that are based on health or safety risks, such that 
the analysis required under section 5-501 of the Executive Order has 
the potential to influence the regulation. Today's final rule 
amendments are not subject to the Executive Order because eligibility 
demonstrations submitted in support of the health-based alternative 
compliance options will be based on noncancer human health reference 
values (e.g., reference concentrations) that are designed to be 
protective of sensitive subpopulations, including children.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    Today's final rule amendments are not a ``significant energy 
actions'' as defined in Executive Order 13211 (66 FR 28355, May 22, 
2001) because it is not likely to have a significant adverse effect on 
the supply, distribution, or use of energy. Further, we have concluded 
that today's final rule amendments are not likely to have any adverse 
energy effects.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) of 1995 (Pub. L. 104-113; 15 U.S.C. 272 note) directs EPA 
to use voluntary consensus standards in their regulatory and 
procurement activities unless to do so would be inconsistent with 
applicable law or otherwise impracticable. Voluntary consensus 
standards are technical standards (e.g., material specifications, test 
methods, sampling procedures, business practices) developed or adopted 
by one or more voluntary consensus bodies. The NTTAA requires EPA to 
provide Congress, through the OMB, with explanations when EPA decides 
not to use available and applicable voluntary consensus standards.
    During the development of the final rule, EPA searched for 
voluntary consensus standards that might be applicable. The search 
identified three voluntary consensus standards that were considered 
practical alternatives to the specified EPA test methods. An assessment 
of these and other voluntary consensus standards is presented in the 
preamble to the final rule (69 FR 55251, September 13, 2004). Today's 
final rule amendments do not involve the use of any additional 
technical standards beyond those cited in the final rule. Therefore, 
EPA did not consider the use of any additional voluntary consensus 
standards.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this action and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A Major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective February 27, 2006.

List of Subjects in 40 CFR Part 63

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Hazardous substances, Intergovernmental 
relations, Reporting and recordkeeping requirements.

    Dated: December 15, 2005.
Stephen L. Johnson,
Administrator.

0
For the reasons stated in the preamble, title 40, chapter 1 of the code 
of Federal Regulations is amended as follows:

PART 63--[AMENDED]

0
1. The authority citation for part 63 continues to read as follows:

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

Subpart DDDDD--[Amended]

0
2. Section 63.7507 is revised to read as follows:


Sec.  63.7507  What are the health-based compliance alternatives for 
the hydrogen chloride (HCl) and total selected metals (TSM) standards?

    (a) As an alternative to the requirement to demonstrate compliance 
with the HCl emission limit in table 1 to this subpart, you may 
demonstrate eligibility for the health-based compliance alternative for 
HCl emissions under the procedures prescribed in appendix A to this 
subpart.
    (b) As an alternative to the requirement to demonstrate compliance 
with the TSM emission limit in table 1 to this subpart based on the sum 
of emissions for the eight selected metals, you may demonstrate 
eligibility for the health-based alternative for manganese emissions 
under the procedures prescribed in appendix A to this subpart and 
comply with the TSM emission standards in table 1 based on the sum of 
emissions for seven selected metals (by excluding manganese emissions 
from the summation of TSM emissions).
* * * * *

0
3. Appendix A to subpart DDDDD is amended as follows:
0
a. By revising the heading.
0
b. In Section 4 by revising paragraph (g).
0
c. In Section 5 by revising paragraphs (c)(2) and (d)(2).
0
d. In Section 6 by revising the introductory text and paragraphs (a) 
and (b).
0
e. In Section 8 by revising paragraphs (b)(1) and adding paragraph (d).
0
f. In Section 9 by revising paragraphs (b), (c)(1) and (c)(2).
0
g. Revising Section 10.
0
h. Revising Section 11.

Appendix A to Subpart DDDDD--Methodology and Criteria for Demonstrating 
Eligibility for the Health-Based Compliance Alternatives

* * * * *

4. How do I determine HAP emissions from my affected source?

* * * * *
    (g) You must determine the maximum hourly emission rate for each 
appropriate emission point according to Equation 1 of this appendix. 
An appropriate emission point is any emission point emitting HCl, 
Cl2, or Manganese from a subpart DDDDD emission unit.
[GRAPHIC] [TIFF OMITTED] TR28DE05.000

Where:

Ei,s = maximum hourly emission rate for HAP i at each 
emission point s associated with a subpart DDDDD emission unit j, 
lbs/hr

[[Page 76934]]

i = applicable HAP, where i = (HCl, Cl2, or Manganese) s 
= individual emission point
j = each subpart DDDDD emission unit associated with an emission 
point, s
t = total number of subpart DDDDD emission units associated with an 
emission point s
Ri,j = emission rate (the 3-run average as determined 
according to table 1 of this appendix or the pollutant concentration 
in the fuel samples analyzed according to Sec.  63.7521) for HAP i 
at subpart DDDDD emission unit j associated with emission point s, 
lb per million Btu.
Ij = Maximum rated heat input capacity of each subpart 
DDDDD unit j emitting HAP i associated with emission point s, 
million Btu per hour.

5. What are the criteria for determining if my facility is eligible for 
the health-based compliance alternatives?

* * * * *
    (c) * * *
    (2) Your site-specific compliance demonstration indicates that 
none of your HI values for HCl and CL2 are greater than 
1.0 at locations where people live or congregate (e.g., schools, 
daycare centers, etc.);
    (d) * * *
    (2) Your site-specific compliance demonstration indicates that 
none of your HQ values for manganese are greater than 1.0 at 
locations where people live or congregate (e.g., schools, daycare 
centers, etc.).

6. How do I conduct a look-up table analysis?

    You may use look-up tables to demonstrate that your facility is 
eligible for either the compliance alternative for HCl emissions 
limit or the compliance alternative for the TSM emissions limit, 
unless your permitting authority determines that the look-up table 
analysis in this section is not applicable to your facility on 
technical grounds due to site-specific variations that are not 
accounted for in the look-up table analysis (e.g. presence of 
complex terrain, rain caps, or building downwash effects).
    (a) HCl compliance alternative. (1) Using the emission rates for 
HCl and Cl2 determined according to section 4 of this 
appendix, calculate, using equation 2 of this appendix, the 
toxicity-weighted emission rate (expressed in HCl-equivalents) for 
each emission point that emits HCl or Cl2 from any 
subpart DDDDD sources. Then, calculate the weighted average stack 
height using equation 3 of this appendix.
[GRAPHIC] [TIFF OMITTED] TR28DE05.001

Where:

TWs = the toxicity-weighted emission rate (in HCl-
equivalent) for each emission point s, lb/hr.
s = individual emission points
EHCl,s = the maximum hourly emission rate for HCl at 
emission point s, lb/hr
ECl2,s = the maximum hourly emission rate for 
Cl2 at emission point s, lb/hr
RVCl2 = the reference value for Cl2
RVHCl = the reference value for HCl
(reference values for HCl and Cl2 can be found at http://www.epa.gov/ttn/atw/toxsource/summary.html
).

[GRAPHIC] [TIFF OMITTED] TR28DE05.002

Where:

HHCl = weighted average stack height for determining the 
maximum allowable HCl-equivalent emission rate (in Table 2 to this 
appendix), m.
s = individual emission points
n = total number of emission points
TWs = toxicity-weighted HCl-equivalent emission rate from 
each emission point (from equation 2), lb/hr.
Hs = height of each individual stack, m
TWT = total toxicity-weighted HCl-equivalent emission 
rate from the source (summed for all emission points), lb/hr.

    (2) Calculate the total toxicity-weighted emission rate for your 
affected source by summing the toxicity-weighted emission rate for 
each appropriate subpart DDDDD emission point.
    (3) Using the weighted average stack height and the minimum 
distance between any appropriate subpart DDDDD emission point at the 
source and the property boundary, identify the appropriate maximum 
allowable toxicity weighted emission rate for your affected source, 
expressed in HCl-equivalents, from table 2 of this appendix. 
Appropriate emission points are those that emit HCl or 
Cl2, or both, from subpart DDDDD units. If one or both of 
these values does not match the exact values in the look-up tables, 
then use the next lowest table value. (Note: If your weighted 
average stack height is less than 5 meters (m), you must use the 5 
meter row.) Your affected source is eligible to comply with the 
health-based alternative for HCl emissions if the value calculated 
in paragraph (a)(2) of this section, determined using the methods 
specified in this appendix, does not exceed the appropriate value in 
table 2 of this appendix.
    (b) TSM Compliance Alternative. Using the emission rates for 
manganese determined according to section 4 of this appendix, 
calculate the total manganese emission rate for your affected source 
by summing the maximum hourly manganese emission rates for all your 
subpart DDDDD units. Identify the appropriate allowable emission 
rate in table 3 of this appendix for your affected source using the 
weighted average stack height value and the minimum distance between 
any appropriate subpart DDDDD emission point at the facility and the 
property boundary. Appropriate emission points are those that emit 
manganese from subpart DDDDD units. If one or both of these values 
does not match the exact values in the look-up tables, then use the 
next lowest table value. (Note: If your weighted average stack 
height is less than 5 meters, you must use the 5 meter row.) Your 
affected source is eligible to comply with the health-based 
alternative for manganese emissions and may exclude manganese when 
demonstrating compliance with the TSM emission limit if the total 
manganese emission rate, determined using the methods specified in 
this appendix, does not exceed the appropriate value specified in 
table 3 of this appendix.
[GRAPHIC] [TIFF OMITTED] TR28DE05.003


[[Page 76935]]


Where:
HMn = weighted average stack height for determining the 
maximum allowable emission rate for manganese (in table 3 to this 
appendix), m.
s = individual emission points
n = total number of emission points
EMn,s= maximum hourly manganese emissions from emission 
point s, lbs/hr.
Hs = height of each individual stack s
EMn,T = total maximum hourly manganese emissions from 
affected source (sum emission rates from all emission points), lb/hr
* * * * *

8. What Must My Health-Based Eligibility Demonstration Contain?

* * * * *
    (b) * * *
    (1) Calculations used to determine the weighted average stack 
height of the subpart DDDDD emission points that emit manganese, 
HCl, or Cl2.
* * * * *
    (d) To be eligible for either health-based compliance 
alternative, the parameters that defined your affected source as 
eligible for the health-based compliance alternatives must be 
submitted to your permitting authority for incorporation into your 
title V permit, as federally enforceable limits, at the same time 
you submit your health-based eligibility demonstration. These 
parameters include, but are not limited to, fuel type, fuel mix 
(annual average), emission rate, type of control devices, process 
parameters (e.g., maximum heat input), and non-process parameters 
(e.g., stack height).

9. When Do I Have to Complete and Submit My Health-Based Eligibility 
Demonstration?

* * * * *
    (b) If you have a new or reconstructed affected source that 
starts up before the effective date of subpart DDDDD, or an affected 
source that is an area source that increases its emissions or its 
potential to emit such that it becomes a major source of HAP before 
the effective date of subpart DDDDD, then you may submit an 
eligibility demonstration at any time after September 13, 2004 but 
you must comply with the emissions limits in table 1 to this subpart 
and all other requirements of subpart DDDDD until your eligibility 
demonstration is submitted to your permitting authority in 
accordance with the requirements of section 10 of this appendix.
    (c) * * *
    (1) You must complete and submit a preliminary eligibility 
demonstration based on the information (e.g., equipment types, 
estimated emission rates, process and non-process parameters, 
reference values, etc.) that will be used to apply for your title V 
permit. This preliminary eligibility demonstration must be submitted 
with your application for approval of construction or 
reconstruction. You must base your preliminary eligibility 
demonstration on the maximum emissions allowed under your title V 
permit. If the preliminary eligibility demonstration indicates that 
your affected source facility is eligible for either compliance 
alternative, then you may start up your new affected source and your 
new affected source will be considered in compliance with the 
alternative standard and subject to the compliance requirements in 
this appendix.
    (2) You must conduct the emission tests or analyses specified in 
section 4 of this appendix upon initial startup and use the results 
of these emissions tests to complete and submit your eligibility 
demonstration within 180 days following your initial startup date.

10. When Do I Become Eligible for the Health-Based Compliance 
Alternatives?

    (a) For existing sources, new sources, or reconstructed sources 
that start up before the effective date of subpart DDDDD, or an 
affected source that is an area source that increases its emissions 
or its potential to emit such that it becomes a major source of HAP 
before the effective date of subpart DDDDD, you are eligible to 
comply with a health-based compliance alternative upon submission of 
a complete demonstration meeting all the requirements of paragraph 8 
for the applicable alternative. However, your eligibility 
demonstration may be reviewed by the permitting authority or by EPA 
to verify that the demonstration meets the requirements of appendix 
A to this subpart and is technically sound (i.e. use of the look-up 
tables is appropriate or the site-specific assessment is technically 
valid). If you are notified by the permitting authority or by EPA of 
any deficiencies in your submission, then you are not eligible for 
the health-based compliance alternative until the permitting 
authority or EPA verifies that the deficiencies are corrected.
    (b) For new or reconstructed sources that start up after the 
effective date of subpart DDDDD, you are eligible to comply with a 
the health-based compliance alternatives upon submission of a 
complete preliminary eligibility determination in accordance with 
paragraph (c)(1) of section 9 that demonstrates your affected source 
is eligible for the applicable alternative. You may then start up 
your source and conduct the necessary testing in accordance with 
paragraph (c)(2) of section 9. The eligibility demonstration 
submitted in accordance with paragraph (c)(2) of section 9 may be 
reviewed by the permitting authority or by EPA to verify that the 
demonstration meets the requirements of appendix A to this subpart 
and is technically sound (i.e. use of the look-up tables is 
appropriate or the site-specific assessment is technically valid). 
If you are notified in writing by the permitting authority of any 
deficiencies in your submission, then you have 30 days to correct 
the deficiencies unless the permitting authority agrees to extend 
this time to a period not to exceed 90 days. If the deficiencies are 
not corrected within the applicable time period, you will not be 
eligible for the health-based compliance alternative until the 
permitting authority verifies that the deficiencies are corrected.
    (c) If the title V permit conditions requested in accordance 
with paragraph (d) of section 8 are disapproved by the permitting 
authority, then your affected source must comply with the applicable 
emission limits, operating limits, and work practice standards in 
subpart DDDDD by the compliance dates specified in Sec.  63.7495. 
Until the requested conditions (or alternative conditions meeting 
the requirements of paragraph (d) of section 8) are incorporated 
into the permit, compliance with the proposed conditions shall be 
considered compliance with the health-based alternative.

11. How Do I Ensure That My Facility Remains Eligible for the Health-
Based Compliance Alternatives?

    (a) You must update your eligibility demonstration and resubmit 
it each time that any of the parameters that defined your affected 
source as eligible for the health-based compliance alternatives 
changes in a way that could result in increased HAP emissions or 
increased risk from exposure to emissions. These parameters include, 
but are not limited to, fuel type, fuel mix (annual average), type 
of control devices, HAP emission rate, stack height, process 
parameters (e.g., heat input capacity), relevant reference values, 
and locations where people live).
    (b) If you are updating your eligibility demonstration to 
account for an action in paragraph (a) of this section that is under 
your control (e.g. change in heat input capacity of your boiler), 
you must submit your revised eligibility demonstration to the 
permitting authority prior to making the change and revise your 
permit to incorporate the change. If your affected source is no 
longer eligible for the health-based compliance alternatives, then 
you must comply with the applicable emission limits, operating 
limits, and compliance requirements in subpart DDDDD prior to making 
the process change and revising your permit. If you are updating 
your eligibility demonstration to account for an action in paragraph 
(a) of this section that is outside of your control (e.g. change in 
a reference value), and that change causes your source to no longer 
be able to meet the criteria for the health-based compliance 
alternatives, your source must comply with the applicable emission 
limits, operating limits, and compliance requirements in subpart 
DDDDD within 3 years.
    (c) Your revised eligibility demonstration may be reviewed by 
the permitting authority or EPA to verify that the demonstration 
meets the requirements of appendix A to this subpart and is 
technically sound (i.e. use of the look-up tables is appropriate or 
the site-specific assessment is technically valid). If you are 
notified by the permitting authority or EPA of any deficiencies in 
your submission, you will not remain eligible for the health-based 
compliance alternatives until the permitting authority or EPA 
verifies that the deficiencies are corrected.
* * * * *
[FR Doc. 05-24299 Filed 12-27-05; 8:45 am]

BILLING CODE 6560-50-P
