[Federal Register Volume 76, Number 33 (Thursday, February 17, 2011)]
[Proposed Rules]
[Pages 9410-9447]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-2866]



[[Page 9409]]

Vol. 76

Thursday,

No. 33

February 17, 2011

Part II





Environmental Protection Agency





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40 CFR Part 63



National Emission Standards for Hazardous Air Pollutants: Primary Lead 
Smelting; Proposed Rule

  Federal Register / Vol. 76, No. 33 / Thursday, February 17, 2011 / 
Proposed Rules  

[[Page 9410]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2004-0305; FRL-9263-2]
RIN 2060-AQ43


National Emission Standards for Hazardous Air Pollutants: Primary 
Lead Smelting

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing amendments to the national emission standards 
for hazardous air pollutants (NESHAP) for Primary Lead Smelting to 
address the results of the residual risk and technology reviews 
conducted as required under sections 112(d)(6) and (f)(2) of the Clean 
Air Act (CAA). These proposed amendments include revisions to the 
emission limits for lead, the addition of a lead concentration in air 
standard, and the modification and addition of testing and monitoring 
and related notification, recordkeeping, and reporting requirements. We 
are also proposing to revise provisions addressing periods of startup, 
shutdown, and malfunction to ensure that they are consistent with a 
recent court decision. Finally, we are proposing revisions to the 
rule's applicability provision to make it consistent with the 
definition of the source category and proposing other minor technical 
changes to the standard. We are also responding to a petition for 
rulemaking filed on the standard with regard to lead as a surrogate and 
regulation of volatile organic compounds (VOC) and acid gases.

DATES: Comments must be received on or before April 4, 2011. Under the 
Paperwork Reduction Act, comments on the information collection 
provisions are best assured of having full effect if the Office of 
Management and Budget (OMB) receives a copy of your comments on or 
before March 21, 2011.
    Public Hearing. If anyone contacts EPA requesting to speak at a 
public hearing by February 28, 2011, a public hearing will be held on 
March 4, 2011.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-HQ-
OAR-2004-0305, by one of the following methods:
     http://www.regulations.gov: Follow the on-line 
instructions for submitting comments.
     E-mail: [email protected], Attention Docket ID Number 
EPA-HQ-OAR-2004-0305.
     Fax: (202) 566-9744, Attention Docket ID Number EPA-HQ-
OAR-2004-0305.
     Mail: U.S. Postal Service, send comments to: EPA Docket 
Center, EPA West (Air Docket), Attention Docket ID Number EPA-HQ-OAR-
2004-0305, U.S. Environmental Protection Agency, Mailcode: 2822T, 1200 
Pennsylvania Ave., NW., Washington, DC 20460. Please include a total of 
two copies. In addition, please mail a copy of your comments on the 
information collection provisions to the Office of Information and 
Regulatory Affairs, Office of Management and Budget (OMB), Attn: Desk 
Officer for EPA, 725 17th Street, NW., Washington, DC 20503.
     Hand Delivery: U.S. Environmental Protection Agency, EPA 
West (Air Docket), Room 3334, 1301 Constitution Ave., NW., Washington, 
DC 20004, Attention Docket ID Number EPA-HQ-OAR-2004-0305. Such 
deliveries are only accepted during the Docket's normal hours of 
operation, and special arrangements should be made for deliveries of 
boxed information.
    Instructions. Direct your comments to Docket ID Number EPA-HQ-OAR-
2004-0305. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available on-line 
at http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
confidential business information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through http://www.regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional information about EPA's public 
docket, visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID Number EPA-HQ-OAR-2004-0305. All documents in the docket are 
listed in the http://www.regulations.gov index. Although listed in the 
index, some information is not publicly available, e.g., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the Internet 
and will be publicly available only in hard copy. Publicly available 
docket materials are available either electronically in http://www.regulations.gov or in hard copy at the EPA Docket Center, EPA West, 
Room 3334, 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 EPA 
Docket Center is (202) 566-1742.
    Public Hearing. If a public hearing is held, it will begin at 10 
a.m. on March 4, 2011 and will be held at EPA's campus in Research 
Triangle Park, North Carolina, or at an alternate facility nearby. 
Persons interested in presenting oral testimony or inquiring as to 
whether a public hearing is to be held should contact Ms. Virginia 
Hunt, Office of Air Quality Planning and Standards, Sector Policies and 
Programs Division, Metals and Minerals Group (D243-02), U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-0832.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Ms. Sharon Nizich, Sector Policies and Programs 
Division (D243-02), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711, telephone (919) 541-2825; fax number: (919) 541-5450; and e-mail 
address: [email protected]. For specific information regarding the 
risk modeling methodology, contact Ms. Elaine Manning, Health and 
Environmental Impacts Division (C539-02), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, Research 
Triangle Park, North Carolina 27711; telephone number: (919) 541-5499; 
fax number: (919) 541-0840; and e-mail address: [email protected]. 
For information about the applicability of

[[Page 9411]]

the NESHAP to a particular entity, contact the appropriate person 
listed in Table 1 to this preamble.

SUPPLEMENTARY INFORMATION:

                 Table 1--List of EPA Contacts For the NESHAP Addressed in This Proposed Action
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                NESHAP for:                          OECA contact \1\                   OAQPS contact \2\
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Primary Lead Smelting.....................  Maria Malave, (202) 564-7027,       Sharon Nizich, (919) 541-2825,
                                             [email protected].               [email protected].
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\1\ EPA's Office of Enforcement and Compliance Assurance.
\2\ EPA's Office of Air Quality Planning and Standards.

I. Preamble Acronyms and Abbreviations

    Several acronyms and terms used to describe industrial processes, 
data inventories, and risk modeling are included in this preamble. 
While this may not be an exhaustive list, to ease the reading of this 
preamble and for reference purposes, the following terms and acronyms 
are defined here:

ADAF Age-dependent Adjustment Factors
AERMOD Air dispersion model used by the HEM-3 model
AEGL Acute Exposure Guideline Levels
ANPRM Advance Notice of Proposed Rulemaking
BACT Best Available Control Technology
CAA Clean Air Act
CBI Confidential Business Information
CEEL Community Emergency Exposure Levels
CEMS Continuous Emissions Monitoring System
CERMS Continuous Emission Rate Monitoring System
CFR Code of Federal Regulations
EJ Environmental Justice
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guidelines
HAP Hazardous Air Pollutants
HI Hazard Index
HEM-3 Human Exposure Model version 3
HON Hazardous Organic National Emissions Standards for Hazardous Air 
Pollutants
HQ Hazard Quotient
IRIS Integrated Risk Information System
Km Kilometer
LAER Lowest Achievable Emission Rate
LOAEL Lowest Observed Adverse Effect Level
MACT Maximum Achievable Control Technology
MACT Code Code within the NEI used to identify processes included in 
a source category
MIR Maximum Individual Risk
NAAQS National Ambient Air Quality Standard
NAC/AEGL Committee National Advisory Committee for Acute Exposure 
Guideline Levels for Hazardous Substances
NAICS North American Industry Classification System
NAS National Academy of Sciences
NATA National Air Toxics Assessment
NESHAP National Emissions Standards for Hazardous Air Pollutants
NEI National Emissions Inventory
NOAEL No Observed Adverse Effects Level
NRC National Research Council
NTTAA National Technology Transfer and Advancement Act
OAQPS EPA's Office of Air Quality Planning and Standards
OECA EPA's Office of Enforcement and Compliance Assurance
OMB Office of Management and Budget
PB-HAP Hazardous air pollutants known to be persistent and bio-
accumulative in the environment
POM Polycyclic Organic Matter
RACT Reasonably Available Control Technology
RBLC RACT/BACT/LAER Clearinghouse
RFA Regulatory Flexibility Act
RfC Reference Concentration
RfD Reference Dose
RTR Residual Risk and Technology Review
SAB Science Advisory Board
SBA Small Business Administration
SCC Source Classification Codes
SF3 2000 Census of Population and Housing Summary File 3
SIP State Implementation Plan
SOP Standard Operating Procedures
SSM Startup, Shutdown, and Malfunction
TOSHI Target Organ-Specific Hazard Index
TPY Tons Per Year
TRIM Total Risk Integrated Modeling System
TTN Technology Transfer Network
UF Uncertainty Factor
UMRA Unfunded Mandates Reform Act
URE Unit Risk Estimate
VOC Volatile Organic Compounds
VOHAP Volatile Organic Hazardous Air Pollutants
WWW Worldwide Web

    Organization of this Document. The following outline is provided to 
aid in the location of information in this preamble.

I. Preamble Acronyms and Abbreviations
II. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
    C. What should I consider as I prepare my comments for EPA?
III. Background
    A. What is the statutory authority for this action?
    B. How did we consider the risk results in making decisions for 
this proposal?
    C. What other actions are we addressing in this proposal?
IV. Analyses Performed and Background for the Source Category and 
MACT Standard
    A. How did we estimate risks posed by the source category?
    B. How did we perform the technology review?
    C. Overview of the source category and MACT standards
V. Analyses Results and Proposed Decisions
    A. What data were used in our risk analyses?
    B. What are the results of the risk assessments and analyses?
    C. What are our proposed decisions on risk acceptability and 
ample margin of safety?
    D. What are the results and proposed decisions from the 
technology review?
    E. Variability
    F. What other actions are we proposing?
VI. Proposed Action
    A. What actions are we proposing as a result of the residual 
risk reviews?
    B. What actions are we proposing as a result of the technology 
reviews?
    C. What other actions are we proposing?
    D. Compliance Dates
VII. Request for Comments
VIII.Submitting Data Corrections
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

II. General Information

A. Does this action apply to me?

    The regulated industrial source category that is the subject of 
this proposal is listed in Table 2 to this preamble. Table 2 is not 
intended to be exhaustive, but rather provides a guide for readers 
regarding entities likely to be affected by this proposed action for 
the source categories listed. This standard, and any changes considered 
in this rulemaking, would be directly

[[Page 9412]]

applicable to sources as a Federal program. Thus, Federal, State, 
local, and tribal government entities are not affected by this proposed 
action. As defined in the source category listing report published by 
EPA in 1992, the Primary Lead Smelting source category is defined as 
any facility engaged in producing lead metal from ore concentrates; 
including, but not limited to, the following smelting processes: 
sintering, reduction, preliminary treatment, and refining 
operations.\1\ As discussed in section III. (C)(3), to be consistent 
with the 1992 listing, EPA is proposing to change the applicability of 
the Primary Lead Smelting NESHAP to apply to any facility that produces 
lead metal from lead ore concentrates. Although the source category 
name in the 1992 listing will remain Primary Lead Smelting (as in 1992 
listing) we are proposing to change the title of the rule to refer to 
Primary Lead Processing. For clarification purposes, all references to 
lead emissions in this preamble means ``lead compounds'' (which is a 
HAP) and all reference to lead production means elemental lead (which 
is not a HAP) as provided under CAA 112(b)(7)).
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    \1\ USEPA. Documentation for Developing the Initial Source 
Category List--Final Report, USEPA/OAQPS, EPA-450/3-91-030, July, 
1992.

                Table 2--Neshap and Industrial Source Categories Affected by This Proposed Action
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              Source category                               NESHAP                NAICS code \1\   MACT code \2\
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Primary Lead Smelting......................  Primary Lead Processing............          331419            0204
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\1\ North American Industry Classification System.
\2\ Maximum Achievable Control Technology.

B. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this proposal will also be available on the World Wide Web (WWW) 
through the Technology Transfer Network (TTN). Following signature by 
the EPA Administrator, a copy of this proposed action will be posted on 
the TTN's policy and guidance page for newly proposed or promulgated 
rules at the following address: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The TTN provides information and technology exchange in 
various areas of air pollution control.
    Additional information is available on the residual risk and 
technology review (RTR) Web page at http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. This information includes source category descriptions and 
detailed emissions and other data that were used as inputs to the risk 
assessments.

C. What should I consider as I prepare my comments for EPA?

    Submitting CBI. Do not submit information containing CBI to EPA 
through http://www.regulations.gov or e-mail. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
a disk or CD ROM that you mail to EPA, mark the outside of the disk or 
CD ROM as CBI and then identify electronically within the disk or CD 
ROM the specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. If 
you submit a CD ROM or disk that does not contain CBI, mark the outside 
of the disk or CD ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and EPA's 
electronic public docket without prior notice. Information marked as 
CBI will not be disclosed except in accordance with procedures set 
forth in 40 CFR part 2. Send or deliver information identified as CBI 
only to the following address: Roberto Morales, OAQPS Document Control 
Officer (C404-02), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711, Attention Docket ID Number EPA-HQ-OAR-2004-0305.

III. Background

A. What is the statutory authority for this action?

    Section 112 of the Clean Air Act (CAA) establishes a two-stage 
regulatory process to address emissions of hazardous air pollutants 
(HAP) from stationary sources. In the first stage, after EPA has 
identified categories of sources emitting one or more of the HAP listed 
in section 112(b) of the CAA, section 112(d) of the CAA calls for us to 
promulgate NESHAP for those sources. ``Major sources'' are those that 
emit or have the potential to emit 10 tons per year (TPY) or more of a 
single HAP or 25 TPY or more of any combination of HAP. For major 
sources, these technology-based standards must reflect the maximum 
degree of emission reductions of HAP achievable (after considering 
cost, energy requirements, and non-air quality health and environmental 
impacts) and are commonly referred to as maximum achievable control 
technology (MACT) standards.
    MACT standards must require the maximum degree of emission 
reduction through the application of measures, processes, methods, 
systems, or techniques, including, but not limited to, measures which 
(A) Reduce the volume of or eliminate pollutants through process 
changes, substitution of materials or other modifications; (B) enclose 
systems or processes to eliminate emissions; (C) capture or treat 
pollutants when released from a process, stack, storage, or fugitive 
emissions point; (D) are design, equipment, work practice, or 
operational standards (including requirements for operator training or 
certification); or (E) are a combination of the above. CAA section 
112(d)(2)(A)-(E). The MACT standards may take the form of design, 
equipment, work practice, or operational standards where EPA first 
determines either that, (A) a pollutant cannot be emitted through a 
conveyance designed and constructed to emit or capture the pollutants, 
or that any requirement for, or use of, such a conveyance would be 
inconsistent with law; or (B) the application of measurement 
methodology to a particular class of sources is not practicable due to 
technological and economic limitations. CAA sections 112(h)(1)-(2).
    The MACT ``floor'' is the minimum control level allowed for MACT 
standards promulgated under CAA section 112(d)(3) and may not be based 
on cost considerations. For new sources, the MACT floor cannot be less 
stringent than the emission control that is achieved in practice by the 
best-

[[Page 9413]]

controlled similar source. The MACT floors for existing sources can be 
less stringent than floors for new sources, but they cannot be less 
stringent than the average emissions limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing 5 sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, we must also consider control options that are more 
stringent than the floor. We may establish standards more stringent 
than the floor based on the consideration of the cost of achieving the 
emissions reductions, any non-air quality health and environmental 
impacts, and energy requirements.
    The EPA is then required to review these technology-based standards 
and to revise them ``as necessary (taking into account developments in 
practices, processes, and control technologies)'' no less frequently 
than every 8 years, under CAA section 112(d)(6). In conducting this 
review, EPA is not obliged to completely recalculate the prior MACT 
determination. NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. Cir., 2008).
    The second stage in standard-setting focuses on reducing any 
remaining ``residual'' risk according to CAA section 112(f). This 
provision requires, first, that EPA prepare a Report to Congress 
discussing (among other things) methods of calculating the risks posed 
(or potentially posed) by sources after implementation of the MACT 
standards, the public health significance of those risks, and the 
recommendations regarding legislation of such remaining risk. EPA 
prepared and submitted this report (Residual Risk Report to Congress, 
EPA-453/R-99-001) in March 1999. Congress did not act in response to 
the report, thereby triggering EPA's obligation under CAA section 
112(f)(2) to analyze and address residual risk.
    Section 112(f)(2) of the CAA requires us to determine for source 
categories subject to certain MACT standards, whether the emissions 
standards provide an ample margin of safety to protect public health. 
If the MACT standards that apply to a source category emitting a HAP 
that is ``classified as a known, probable, or possible human carcinogen 
do not reduce lifetime excess cancer risks to the individual most 
exposed to emissions from a source in the category or subcategory to 
less than one-in-one million,'' EPA must promulgate residual risk 
standards for the source category (or subcategory) as necessary to 
provide an ample margin of safety to protect public health. CAA section 
112(f)(2)(A). In doing so, EPA may adopt standards equal to existing 
MACT standards if EPA determines that the existing standards are 
sufficiently protective. As stated in NRDC v. EPA, 529 F.3d 1077, 1083 
(D.C. Dir. 2008), ``If EPA determines that the existing technology-
based standards provide an `ample margin of safety,' then the Agency is 
free to readopt those standards during the residual risk rulemaking.'' 
Section 112(f)(2) of the Clean Air Act further states that EPA must 
also adopt more stringent standards, if necessary, to ``prevent taking 
into consideration costs, energy, safety, and other relevant factors, 
an adverse environmental effect.'' \2\
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    \2\ ``Adverse environmental effect'' is defined in CAA section 
112(a)(7) as any significant and widespread adverse effect, which 
may be reasonably anticipated to wildlife, aquatic life, or natural 
resources, including adverse impacts on populations of endangered or 
threatened species or significant degradation of environmental 
qualities over broad areas.
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    When Section 112(f)(2) of the CAA was enacted in 1990, it expressly 
preserved our use of the two-step process for developing standards to 
address any residual risk and our interpretation of ``ample margin of 
safety'' developed in the National Emission Standards for Hazardous Air 
Pollutants: Benzene Emissions from Maleic Anhydride Plants, 
Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment 
Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 
38044, September 14, 1989). The first step in this process is the 
determination of acceptable risk. The second step provides for an ample 
margin of safety to protect public health, which is the level at which 
the standards are set (unless a more stringent standard is required to 
prevent, taking into consideration costs, energy, safety, and other 
relevant factors, an adverse environmental effect).
    The terms ``individual most exposed,'' ``acceptable level,'' and 
``ample margin of safety'' are not specifically defined in the CAA. 
However, CAA section 112(f)(2)(B) preserves the interpretation set out 
in the Benzene NESHAP, and the Court in NRDC v. EPA, concluded that 
EPA's interpretation of subsection 112(f)(2) is a reasonable one. See 
NRDC v. EPA, 529 F.3d at 1083 (D.C. Cir. 2008), which says 
``[S]ubsection 112(f)(2)(B) expressly incorporates EPA's interpretation 
of the Clean Air Act from the Benzene standard, complete with a 
citation to the Federal Register.'' See also, A Legislative History of 
the Clean Air Act Amendments of 1990, volume 1, p. 877 (Senate debate 
on Conference Report). We notified Congress in the Residual Risk Report 
to Congress that we intended to use the Benzene NESHAP approach in 
making CAA section 112(f) residual risk determinations (EPA-453/R-99-
001, p. ES-11).
    In the Benzene NESHAP, we stated as an overall objective:

    * * * in protecting public health with an ample margin of 
safety, we strive to provide maximum feasible protection against 
risks to health from hazardous air pollutants by (1) protecting the 
greatest number of persons possible to an individual lifetime risk 
level no higher than approximately 1-in-1 million; and (2) limiting 
to no higher than approximately 1-in-10 thousand [i.e., 100-in-1 
million] the estimated risk that a person living near a facility 
would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.

    The Agency also stated that, ``The EPA also considers incidence 
(the number of persons estimated to suffer cancer or other serious 
health effects as a result of exposure to a pollutant) to be an 
important measure of the health risk to the exposed population. 
Incidence measures the extent of health risks to the exposed population 
as a whole, by providing an estimate of the occurrence of cancer or 
other serious health effects in the exposed population.'' The Agency 
went on to conclude that ``estimated incidence would be weighed along 
with other health risk information in judging acceptability.'' As 
explained more fully in our Residual Risk Report to Congress, EPA does 
not define ``rigid line[s] of acceptability,'' but considers rather 
broad objectives to be weighed with a series of other health measures 
and factors (EPA-453/R-99-001, p. ES-11). The determination of what 
represents an ``acceptable'' risk is based on a judgment of ``what 
risks are acceptable in the world in which we live'' (Residual Risk 
Report to Congress, p. 178, quoting the Vinyl Chloride decision at 824 
F.2d 1165) recognizing that our world is not risk-free.
    In the Benzene NESHAP, we stated that ``EPA will generally presume 
that if the risk to [the maximum exposed] individual is no higher than 
approximately 1-in-10 thousand, that risk level is considered 
acceptable.'' 54 FR 38045. We discussed the maximum individual lifetime 
cancer risk as being ``the estimated risk that a person living near a 
plant would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.'' Id. We explained that this measure of 
risk ``is an estimate of the upper bound of risk based on conservative 
assumptions, such as continuous exposure for 24 hours per day for 70 
years.'' Id. We

[[Page 9414]]

acknowledge that maximum individual lifetime cancer risk ``does not 
necessarily reflect the true risk, but displays a conservative risk 
level which is an upper-bound that is unlikely to be exceeded.'' Id.
    Understanding that there are both benefits and limitations to using 
maximum individual lifetime cancer risk as a metric for determining 
acceptability, we acknowledged in the 1989 Benzene NESHAP that 
``consideration of maximum individual risk * * * must take into account 
the strengths and weaknesses of this measure of risk.'' Id. 
Consequently, the presumptive risk level of 100-in-1 million (1-in-10 
thousand) provides a benchmark for judging the acceptability of maximum 
individual lifetime cancer risk, but does not constitute a rigid line 
for making that determination.
    The Agency also explained in the 1989 Benzene NESHAP the following: 
``In establishing a presumption for MIR [maximum individual cancer 
risk], rather than a rigid line for acceptability, the Agency intends 
to weigh it with a series of other health measures and factors. These 
include the overall incidence of cancer or other serious health effects 
within the exposed population, the numbers of persons exposed within 
each individual lifetime risk range and associated incidence within, 
typically, a 50-kilometer (km) exposure radius around facilities, the 
science policy assumptions and estimation uncertainties associated with 
the risk measures, weight of the scientific evidence for human health 
effects, other quantified or unquantified health effects, effects due 
to co-location of facilities, and co-emission of pollutants.'' Id.
    In some cases, these health measures and factors taken together may 
provide a more realistic description of the magnitude of risk in the 
exposed population than that provided by maximum individual lifetime 
cancer risk alone. As explained in the Benzene NESHAP, ``[e]ven though 
the risks judged ``acceptable'' by EPA in the first step of the Vinyl 
Chloride inquiry are already low, the second step of the inquiry, 
determining an ``ample margin of safety,'' again includes consideration 
of all of the health factors, and whether to reduce the risks even 
further.'' In the ample margin of safety decision process, the Agency 
again considers all of the health risks and other health information 
considered in the first step. Beyond that information, additional 
factors relating to the appropriate level of control will also be 
considered, including costs and economic impacts of controls, 
technological feasibility, uncertainties, and any other relevant 
factors. Considering all of these factors, the Agency will establish 
the standard at a level that provides an ample margin of safety to 
protect the public health, as required by CAA section 112(f). 54 FR 
38046.

B. How did we consider the risk results in making decisions for this 
proposal?

    As discussed in section III.A of this preamble, we apply a two-step 
process for developing standards to address residual risk. In the first 
step, EPA determines if risks are acceptable. This determination 
``considers all health information, including risk estimation 
uncertainty, and includes a presumptive limit on maximum individual 
lifetime [cancer] risk (MIR) \3\ of approximately 1-in-10 thousand 
[i.e., 100-in-1 million].'' 54 FR 38045. In the second step of the 
process, EPA sets the standard at a level that provides an ample margin 
of safety ``in consideration of all health information, including the 
number of persons at risk levels higher than approximately 1-in-1 
million, as well as other relevant factors, including costs and 
economic impacts, technological feasibility, and other factors relevant 
to each particular decision.'' Id.
---------------------------------------------------------------------------

    \3\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk were an individual exposed to the maximum level 
of a pollutant for a lifetime.
---------------------------------------------------------------------------

    In past residual risk actions, EPA has presented and considered a 
number of human health risk metrics associated with emissions from the 
category under review, including: the MIR; the numbers of persons in 
various risk ranges; cancer incidence; the maximum non-cancer hazard 
index (HI); and the maximum acute non-cancer hazard (72 FR 25138, May 
3, 2007; 71 FR 42724, July 27, 2006). In our most recent proposals (75 
FR 65068, October 21, 2010 and 75 FR 80220, December 21, 2010), EPA 
also presented and considered additional measures of health 
information, including: estimates of ``facility-wide'' risks (risks 
from all HAP emissions from the facility at which the source category 
is located); \4\ demographic analyses (analyses of the distributions of 
HAP-related risks across different social, demographic, and economic 
groups living near the facilities); and estimates of the risks 
associated with the maximum level of emissions which might be allowed 
by the current MACT standards (see, e.g., 75 FR 65068, October 21, 2010 
and 75 FR 80220, December 21, 2010). EPA also discussed and considered 
risk estimation uncertainties. EPA is providing this same type of 
information in support of the proposed actions described in this 
Federal Register notice.
---------------------------------------------------------------------------

    \4\ EPA previously provided estimates of total facility risk in 
a residual risk proposal for coke oven batteries (69 FR 48338, 
August 9, 2004).
---------------------------------------------------------------------------

    The Agency is considering all available health information to 
inform our determinations of risk acceptability and ample margin of 
safety under CAA section 112(f). Specifically, as explained in the 
Benzene NESHAP, ``the first step judgment on acceptability cannot be 
reduced to any single factor'' and thus ``[t]he Administrator believes 
that the acceptability of risk under section 112 is best judged on the 
basis of a broad set of health risk measures and information.'' 54 FR 
at 38046. Similarly, with regard to making the ample margin of safety 
determination, as stated in the Benzene NESHAP ``[I]n the ample margin 
decision, the Agency again considers all of the health risk and other 
health information considered in the first step. Beyond that 
information, additional factors relating to the appropriate level of 
control will also be considered, including cost and economic impacts of 
controls, technological feasibility, uncertainties, and any other 
relevant factors.'' Id.
    The Agency acknowledges that flexibility is provided by the Benzene 
NESHAP regarding what factors EPA might consider in making 
determinations and how they might be weighed for each source category. 
In responding to comment on our policy under the Benzene NESHAP, EPA 
explained that: ``The policy chosen by the Administrator permits 
consideration of multiple measures of health risk. Not only can the MIR 
figure be considered, but also incidence, the presence of non-cancer 
health effects, and the uncertainties of the risk estimates. In this 
way, the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be weighed 
in each individual case. This approach complies with the Vinyl Chloride 
mandate that the Administrator ascertain an acceptable level of risk to 
the public by employing [her] expertise to assess available data. It 
also complies with the Congressional intent behind the CAA, which did 
not exclude the use of any particular measure of public health risk 
from the EPA's consideration with respect to CAA section 112 
regulations, and, thereby, implicitly permits consideration of any and 
all measures of health risk which the Administrator, in [her] judgment, 
believes are appropriate to determining what will `protect the public 
health.' '' 54 FR at 38057.
    For example, the level of the MIR is only one factor to be weighed 
in

[[Page 9415]]

determining acceptability of risks. It is explained in the Benzene 
NESHAP that ``an MIR of approximately 1-in-10 thousand should 
ordinarily be the upper end of the range of acceptability. As risks 
increase above this benchmark, they become presumptively less 
acceptable under CAA section 112, and would be weighed with the other 
health risk measures and information in making an overall judgment on 
acceptability. Or, the Agency may find, in a particular case, that a 
risk that includes MIR less than the presumptively acceptable level is 
unacceptable in the light of other health risk factors.'' Id. at 38045. 
Similarly, with regard to the ample margin of safety analysis, EPA 
stated in the Benzene NESHAP that: ``* * * EPA believes the relative 
weight of the many factors that can be considered in selecting an ample 
margin of safety can only be determined for each specific source 
category. This occurs mainly because technological and economic factors 
(along with the health-related factors) vary from source category to 
source category.'' Id. at 38061.
    EPA wishes to point out that certain health information has not 
been considered to date in making residual risk determinations. In 
assessing risks to populations in the vicinity of the facilities in 
each category, we present estimates of risk associated with HAP 
emissions from the source category alone (source category risk 
estimates) and HAP emissions from the entire facility at which the 
covered source category is located (facility-wide risk estimates). We 
do not attempt to characterize the risks associated with all HAP 
emissions impacting the populations living near the sources in these 
categories. That is, at this time, we do not attempt to quantify those 
HAP risks that may be associated with mobile source emissions, natural 
source emissions, persistent environmental pollution, or atmospheric 
transformation in the vicinity of the sources in these categories.
    The Agency understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. This is 
particularly important when assessing non-cancer risks, where 
pollutant-specific exposure levels (e.g., Reference Concentration 
(RfC)) are based on the assumption that thresholds exist for adverse 
health effects. For example, the Agency recognizes that, although 
exposures attributable to emissions from a source category or facility 
alone may not indicate the potential for increased risk of adverse non-
cancer health effects in a population, the exposures resulting from 
emissions from the facility in combination with emissions from all of 
the other sources (e.g., other facilities) to which an individual is 
exposed may be sufficient to result in increased risk of adverse non-
cancer health effects. In May 2010, the Science Advisory Board (SAB) 
advised us ``* * * that RTR assessments will be most useful to decision 
makers and communities if results are presented in the broader context 
of aggregate and cumulative risks, including background concentrations 
and contributions from other sources in the area.'' \5\
---------------------------------------------------------------------------

    \5\ EPA's responses to this and all other key recommendations of 
the SAB's advisory on RTR risk assessment methodologies (which is 
available at: http://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf) 
are outlined in a memo to this rulemaking docket from David Guinnup 
entitled, EPA's Actions in Response to the Key Recommendations of 
the SAB Review of RTR Risk Assessment Methodologies.
---------------------------------------------------------------------------

    While we are interested in placing source category and facility-
wide HAP risks in the context of total HAP risks from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. At this point, we believe that such 
estimates of total HAP risks will have significantly greater associated 
uncertainties than for the source category or facility-wide estimates, 
and hence compounding the uncertainty in any such comparison. This is 
because we have not conducted a detailed technical review of HAP 
emissions data for source categories and facilities that have not 
previously undergone an RTR review or are not currently undergoing such 
review. We are requesting comment on whether and how best to estimate 
and evaluate total HAP exposure in our assessments, and, in particular, 
on whether and how it might be appropriate to use information from 
EPA's National Air Toxics Assessment (NATA) to support such estimates. 
We are also seeking comment on how best to consider various types and 
scales of risk estimates when making our acceptability and ample margin 
of safety determinations under CAA section 112(f). Additionally, we are 
seeking comments and recommendations for any other comparative measures 
that may be useful in the assessment of the distribution of HAP risks 
across potentially affected demographic groups.

C. What other actions are we addressing in this proposal?

1. Startup, Shutdown and Malfunction
    This proposed action would amend the provisions of the existing 
NESHAP that apply to periods of startup, shutdown, and malfunction 
(SSM). The proposed revisions of these provisions result from a Court 
decision that vacated portions of two provisions in EPA's ``General 
Provisions'' regulation under CAA section 112, governing the emissions 
of HAP during periods of SSM. The current Primary Lead Smelting MACT 
includes references to the vacated provisions in the General Provisions 
rule.
    We are proposing to revise the Primary Lead Smelting MACT standard 
to require affected sources to comply with the emission limitations at 
all times and during periods of SSM. Specifically, we are proposing 
several revisions to subpart TTT including revising Table 1 to indicate 
that the requirements of the General Provisions pertaining to SSM do 
not apply and to revise language in Sec.  63.1547 (g)(1) and (2) to 
remove the exemption for bag leak detection alarm time attributable to 
SSM from total allowed alarm time. For reasons discussed below, we are 
also proposing to promulgate an affirmative defense to civil penalties 
for exceedances of emission standards caused by malfunctions, as well 
as criteria for establishing the affirmative defense. These changes 
would go into effect upon the effective date of promulgation of the 
final rule.
    The United States Court of Appeals for the District of Columbia 
Circuit vacated portions of two provisions in EPA's CAA Section 112 
regulations governing the emissions of HAP during periods of SSM. 
Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 
S. Ct. 1735 (U.S. 2010). Specifically, the Court vacated the SSM 
exemptions contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), that 
are part of a regulation commonly known as the ``General Provisions 
Rule,'' that EPA had promulgated under section 112 of the CAA. When 
incorporated into CAA section 112(d) regulations for specific source 
categories, these two provisions exempt sources from the requirement to 
comply with the otherwise applicable CAA section 112(d) emission 
standard during periods of SSM.
    We are proposing the elimination of the SSM exemption in this rule. 
Consistent with Sierra Club v. EPA, EPA is proposing standards in this 
rule that apply at all times. We are also proposing several revisions 
to Table 1 (the General Provisions Applicability table). For

[[Page 9416]]

example, we are proposing to eliminate the incorporation of the General 
Provisions' requirement that the source develop an SSM plan. We also 
are proposing to eliminate or revise certain recordkeeping and 
reporting that relate to the SSM exemption. EPA has attempted to ensure 
that we have not included in the proposed regulatory language any 
provisions that are inappropriate, unnecessary, or redundant in the 
absence of the SSM exemption. We are specifically seeking comment on 
whether there are any such provisions that we have inadvertently 
incorporated or overlooked.
    In proposing standards in this rule, EPA has taken into account 
startup and shutdown periods and, for the reasons explained below, has 
not proposed different standards for those periods. Information on 
periods of startup and shutdown in the industry indicate that emissions 
during these periods do not increase. Furthermore, all processes are 
controlled by either control devices or work practices and these 
controls would not typically be affected by an SSM event. Also, 
compliance with the standard already requires averaging of emissions 
over a three month period, which accounts for the variability of 
emissions that may result during periods of startup and shutdown. 
Therefore, separate standards for periods of startup and shutdown are 
not being proposed.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. However, by 
contrast, malfunction is defined as a ``sudden, infrequent, and not 
reasonably preventable failure of air pollution control and monitoring 
equipment, process equipment, or a process to operate in a normal or 
useful manner * * *'' (40 CFR 63.2). EPA has determined that 
malfunctions should not be viewed as a distinct operating mode and, 
therefore, any emissions that occur at such times do not need to be 
factored into development of CAA section 112(d) standards, which, once 
promulgated, apply at all times. In Mossville Environmental Action Now 
v. EPA, 370 F.3d 1232, 1242 (D.C. Cir. 2004), the court upheld as 
reasonable standards that had factored in variability of emissions 
under all operating conditions. However, nothing in section 112(d) or 
in case law requires that EPA anticipate and account for the 
innumerable types of potential malfunction events in setting emission 
standards. See, Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 
1978)(``In the nature of things, no general limit, individual permit, 
or even any upset provision can anticipate all upset situations. After 
a certain point, the transgression of regulatory limits caused by 
`uncontrollable acts of third parties,' such as strikes, sabotage, 
operator intoxication or insanity, and a variety of other 
eventualities, must be a matter for the administrative exercise of 
case-by-case enforcement discretion, not for specification in advance 
by regulation.'').
    Further, it is reasonable to interpret section 112(d) as not 
requiring EPA to account for malfunctions in setting emission 
standards. For example, we note that CAA section 112 uses the concept 
of ``best performing'' sources in defining MACT, the level of 
stringency that major source standards must meet. Applying the concept 
of ``best performing'' to a source that is malfunctioning presents 
significant difficulties. The goal of best performing sources is to 
operate in such a way as to avoid malfunctions of their units.
    Moreover, even if malfunctions were considered a distinct operating 
mode, we believe it would be impracticable to take malfunctions into 
account in setting CAA section 112(d) standards for Primary Lead 
Smelting. As noted above, by definition, malfunctions are sudden and 
unexpected events and it would be difficult to set a standard that 
takes into account the myriad different types of malfunctions that can 
occur across all sources in the category. Moreover, malfunctions can 
vary in frequency, degree, and duration, further complicating standard 
setting.
    In the unlikely event that a source fails to comply with the 
applicable CAA section 112(d) standards as a result of a malfunction 
event, EPA would determine an appropriate response based on, among 
other things, the good faith efforts of the source to minimize 
emissions during malfunction periods, including preventative and 
corrective actions, as well as root cause analyses to ascertain and 
rectify excess emissions. EPA would also consider whether the source's 
failure to comply with the CAA section 112(d) standard was, in fact, 
``sudden, infrequent, not reasonably preventable'' and was not instead 
``caused in part by poor maintenance or careless operation.'' 40 CFR 
63.2 (definition of malfunction).
    Finally, EPA recognizes that even equipment that is properly 
designed and maintained can sometimes fail and that such failure can 
sometimes cause or contribute to an exceedance of the relevant emission 
standard. (See, e.g., State Implementation Plans: Policy Regarding 
Excessive Emissions During Malfunctions, Startup, and Shutdown (Sept. 
20, 1999); Policy on Excess Emissions During Startup, Shutdown, 
Maintenance, and Malfunctions (Feb. 15, 1983).) EPA is therefore 
proposing to add to the final rule an affirmative defense to civil 
penalties for exceedances of emission limits that are caused by 
malfunctions. See 40 CFR 63.1542 (defining ``affirmative defense'' to 
mean, in the context of an enforcement proceeding, a response or 
defense put forward by a defendant, regarding which the defendant has 
the burden of proof, and the merits of which are independently and 
objectively evaluated in a judicial or administrative proceeding). We 
also are proposing other regulatory provisions to specify the elements 
that are necessary to establish this affirmative defense; the source 
must prove by a preponderance of the evidence that it has met all of 
the elements set forth in Sec.  63.1551. (See 40 CFR 22.24.) The 
criteria ensure that the affirmative defense is available only where 
the event that causes an exceedance of the emission limit meets the 
narrow definition of malfunction in 40 CFR 63.2 (sudden, infrequent, 
not reasonably preventable and not caused by poor maintenance and/or 
careless operation). For example, to successfully assert the 
affirmative defense, the source must prove by a preponderance of the 
evidence that excess emissions ``[w]ere caused by a sudden, short, 
infrequent, and unavoidable failure of air pollution control and 
monitoring equipment, process equipment, or a process to operate in a 
normal or usual manner * * *'' The criteria also are designed to ensure 
that steps are taken to correct the malfunction, to minimize emissions 
in accordance with Sec. Sec.  63.1543(i) and 63.1544(e) and to prevent 
future malfunctions. For example, the source must prove by a 
preponderance of the evidence that ``[r]epairs were made as 
expeditiously as possible when the applicable emission limitations were 
being exceeded * * *'' and that ``[a]ll possible steps were taken to 
minimize the impact of the excess emissions on ambient air quality, the 
environment and human health * * *.'' In any judicial or administrative 
proceeding, the Administrator may challenge the assertion of the 
affirmative defense and, if the respondent has not met its burden of 
proving all of the requirements in the affirmative defense, appropriate 
penalties may be assessed in accordance with section 113 of the Clean 
Air Act (see also 40 CFR part 22.77).
    Specifically, we are proposing the following changes to the rule.
     Added general duty requirements in Sec. Sec.  63.1543 and 
63.1544 to replace General Provision requirements that reference 
vacated SSM provisions.

[[Page 9417]]

     Added replacement language that eliminates the reference 
to SSM exemptions applicable to performance tests in Sec.  63.1546.
     Added paragraphs in Sec.  63.1549(e) requiring the 
reporting of malfunctions as part of the affirmative defense 
provisions.
     Added paragraphs in Sec.  63.1549(b) requiring the keeping 
of certain records during malfunctions as part of the affirmative 
defense provisions.
     Revised Table 1 to reflect changes in the applicability of 
the General Provisions to this subpart resulting from a court vacatur 
of certain SSM requirements in the General Provisions.
2. Lead as a Surrogate and Regulation of Volatile Organic Compounds 
(VOC) and Acid Gas Emissions
    In a January 14, 2009, petition for rulemaking filed by the Natural 
Resources Defense Council and Sierra Club, the petitioners claim that 
for the Primary Lead Smelting MACT, EPA relied on lead as a surrogate 
for all HAP and they claim that it was inappropriate for EPA to do so 
in absence of a showing that lead is an appropriate surrogate for all 
other HAP (such as mercury, acid gases, and volatile organic compounds 
(VOC)). The petitioners asserted that EPA should set standards for 
other HAP absent a showing that lead is an appropriate surrogate for 
these HAP. They also assert that EPA's PM standard does not reflect the 
emission level achieved by the best performing sources and that EPA 
must re-open the rule to set floors for PM in accordance with CAA 
section 112(d)(3). A copy of the petition is included in the docket.
    As part of this rulemaking, EPA is responding to the claims made by 
the petitioners regarding the Primary Lead Smelting MACT.
    As an initial matter, the petitioners are incorrect in their claim 
that EPA considers lead as a surrogate for all HAP. Rather, EPA used 
lead as a surrogate only for other metal HAP compounds in establishing 
the emissions limit in the current MACT standard for this source 
category (63 FR 19206 and 64 FR 30195). EPA determined in the 1999 rule 
that lead, a nonvolatile metal HAP, is an appropriate surrogate for 
other nonvolatile metal HAP including antimony, arsenic, chromium, 
nickel, manganese, and cadmium. In the proposed rule for the Primary 
Lead Smelting MACT (63 FR 19206), EPA discussed the use of lead as a 
surrogate for metal HAP emissions and explained that strong 
correlations exist between emissions of lead and other metal HAP and 
that the technologies identified for the control of metal HAP are the 
same as those used to control lead emissions. Therefore, EPA expected 
that the standards requiring control of lead would achieve similar 
control of the other metal HAP emitted from primary lead smelters. No 
adverse comments were received regarding EPA's proposed rationale for 
relying on lead as a surrogate for other metal HAP emitted by these 
sources and EPA adopted that rationale in the final rule promulgating 
the Primary Lead Smelting MACT. The petitioners do not have any 
substantive basis as to why EPA's rationale is not supported. Nor do 
they claim that there is any new information that would support re-
opening this issue. Thus they fail to present a basis for re-opening 
this issue.
    The petitioners also insist that EPA should have set standards for 
VOC and acid gases that are HAP because lead would not be a surrogate 
for these pollutants. EPA noted in the original proposal that due to 
small amounts of coke fed to the blast furnace, organic HAP (VOC) was 
emitted at a rate so low as to be infeasible to reduce. Again, no 
adverse comments were received on EPA's proposed conclusions, which 
were adopted in the final rule, and the petitioners do not now provide 
substantive support for their claim. Nor do they explain why any such 
claim could not have been raised during the initial rulemaking. Thus, 
they fail to present a basis for re-opening the rule on this issue.
    Finally, petitioners claim that the ``PM standard does not reflect 
the emission level achieved by the best performing sources.'' This 
claim is unclear as there is no PM standard in the Primary Lead 
Smelting MACT. The monitoring provisions provide that PM should be 
measured in relation to a predetermined PM level as one test for 
indicating baghouse performance. However, the PM levels are not 
enforceable emission limits, but merely an indication that the baghouse 
may not be operating properly. Again, these provisions were clearly 
explained in the proposed and final Primary Lead Smelting MACT 
rulemakings. Any claims concerning the appropriateness of these 
monitoring requirements should have been raised during the initial 
rulemaking process. Petitioners do not claim any new grounds for 
raising this issue now. Thus, the petition fails to provide a basis for 
re-opening the MACT.
3. Modification of the Applicability Provision
    EPA is proposing to amend the applicability section to apply to any 
facility processing lead ore concentrate to produce lead metal. Under 
the current applicability provisions, the affected sources include any 
sinter machine, blast furnace, dross furnace, process fugitive source, 
and fugitive dust source located at a primary lead smelter and excludes 
secondary lead smelters, lead refiners, or lead remelters. Combined 
with the current definition for ``primary lead smelter,'' the current 
rule effectively only applies to facilities that produce lead metal 
from lead sulfide ore concentrates using pyrometallurgical techniques. 
While the only processes available for the production of lead from lead 
ore concentrate at the time the MACT rule was developed were 
pyrometallurgical techniques, that applicability language is narrower 
than the primary lead smelting source category description EPA 
identified in its source category listing issued pursuant to CAA 
section 112(c)(1), Documentation for Developing the Initial Source 
Category List (EPA-450/3-91-030, July 1992). In the source category 
listing, EPA defined the primary lead smelting source category as 
follows: ``The Primary Lead Smelting source category includes any 
facility engaged in producing lead metal from ore concentrates. The 
category includes, but is not limited to, the following smelting 
processes: sintering reduction, preliminary treatment, and refining 
operations. The sintering process includes an updraft or downdraft 
sintering machine. The reduction process includes the blast furnace, 
electric smelting furnace with a converter or reverberatory furnace, 
and slag fuming furnace process units. The preliminary treatment 
process includes the drossing kettles and dross reverberatory furnace 
process units. The refining process includes the refinery process 
unit.'' The definition is clear that the primary intent was to cover 
sources that produce lead metal from ore concentrates, which would 
``include'' the use of a pyrometallurgical process, but would not be 
limited to such. As noted previously, at the time we promulgated the 
MACT standard, the only method of producing lead metal from ore 
concentrates was through use of pyrometallurgical techniques and we 
adopted an applicability provision that focused on that process.
    However, information provided by the sole operating primary lead 
smelting facility indicates that lead production is likely to continue 
at the current Doe Run facility, although using a process other than a 
pyrometallurgical technique. The new lead facility would continue to 
process lead ore concentrate

[[Page 9418]]

in order to produce lead metal. Based on the current applicability 
section and definitions, it could be interpreted that the future lead 
producing process, using techniques other than pyrometallurgical, would 
not be subject to the NESHAP for primary lead smelters. Such a limited 
interpretation is not consistent with EPA's intent as evidenced by the 
broader definition in the source category list. Therefore, EPA is 
proposing to amend the applicability section to specify that the MACT 
applies to any lead processing facility that produces lead metal from 
lead ore concentrate. Consistent with the proposed revision to the 
applicability section, we are proposing to remove the definition of 
``primary lead smelter'' and add a definition of ``primary lead 
processor'' which means any facility engaged in the production of lead 
metal from lead sulfide ore concentrates through the use of 
pyrometallurgical or other techniques. In addition, we are proposing to 
replace ``primary lead smelter'' with ``primary lead processor'' 
throughout 40 CFR subpart TTT. (Sec.  63.1541 through Sec.  63.1545, 
Sec.  63.1547 through Sec.  63.1549). We are specifically asking for 
comment on this proposed change in the definition.
    Because there is only one primary lead processing facility in the 
U.S., there will be no impact of this change on the number of existing 
facilities covered by the MACT.
    We note, however, that although we are changing the applicability 
section to clarify that the MACT applies to all processes for producing 
lead metal from ore concentrates, we are not today proposing a specific 
MACT standard that would apply to the as-yet undemonstrated 
hydrometallurgical process which Doe Run has indicated that it plans to 
build at the current Doe Run facility. If and when that process begins 
operation, we will consider whether to revise the MACT standard to 
specifically address that process or any other new processes. However, 
the limits applicable to specific emission sources currently in 
operation as specified in the MACT and as revised under CAA sections 
112(d)(6) and (f)(2) in this rulemaking would continue to apply to any 
emission source at the facility that continues in operation, such as 
the refinery. In addition, to the extent that we establish a final air 
lead concentration limit as proposed in Sec.  63.1544, those limits 
would also continue to apply to the facility. We also are proposing 
that the plant-wide emission limit we are proposing today should 
continue to apply to any facility that meets the revised applicability 
definition, but we are specifically soliciting comment on whether it 
should apply.
    We are also taking this opportunity to clarify the reference to 
``lead refiners'' in the second sentence of the applicability section, 
which provides that the MACT standard does not apply to ``secondary 
lead smelters, lead refiners, or lead remelters.'' The intent of this 
provision was to make clear that secondary lead smelters would not be 
subject to the rule because secondary lead smelters were listed as a 
separate source category and addressed in a separate MACT standard. 
With regard to lead refiners and lead remelters, the intent was to 
provide that these activities, to the extent that they are not located 
at facilities that produce lead from lead ore concentrate, would not be 
subject to the Primary Lead Smelting MACT. However, it was not the 
intention of the rule to exempt kettle refining operations included as 
part of a primary lead processing facility. Therefore, EPA is proposing 
to add definitions for secondary lead smelters, lead refiners, and lead 
remelters in the definitions section of this NESHAP in order to further 
clarify the exemption in the applicability provisions with regard to 
these types of facilities. As this change only clarifies an existing 
provision in the rule, there will be no impact to the number of 
facilities covered by the rule.
4. Other Changes
    The following lists additional minor changes we are proposing. This 
list includes rule changes that address editorial errors and plain 
language revisions.
     As part of EPA's effort to incorporate plain language into 
its regulations, replaced the word ``shall'' with ``must.'' (Sec.  
63.1543 through Sec.  63.1550)
     Correction to the original rule (``thru'' replaced with 
``through'' in the definition of ``tapping location''). (Sec.  63.1542)
     Minor wording change to definition of ``fugitive dust 
source'' to clarify meaning. (Sec.  63.1542)

IV. Analyses Performed and Background of the Source Category and MACT 
Standard

    As discussed above, in this proposed rule we are proposing action 
to address the RTR requirements of CAA sections 112(d)(6) and (f)(2) 
for the Primary Lead Smelting MACT standard. In this section, we 
describe the analyses performed to support the proposed decisions for 
the RTR for this source category and we also include background 
information on the source category and the MACT standard.

A. How did we estimate risks posed by the source category?

    The EPA conducted a risk assessment that provided estimates of the 
MIR posed by the HAP emissions from the one source in the source 
category, the distribution of cancer risks within the exposed 
populations, cancer incidence, HI for chronic exposures to HAP with the 
potential to cause non-cancer health effects, hazard quotients (HQ) for 
acute exposures to HAP with the potential to cause non-cancer health 
effects, and an evaluation of the potential for adverse environmental 
effects. The risk assessments consisted of seven primary steps, as 
discussed below.
    The docket for this rulemaking contains the following document 
which provides more information on the risk assessment inputs and 
models: Draft Residual Risk Assessment for the Primary Lead Smelting 
Source Category.
1. Establishing the Nature and Magnitude of Actual Emissions and 
Identifying the Emissions Release Characteristics
    For the Primary Lead Smelting source category, we compiled a 
preliminary dataset using readily available information, reviewed the 
data, and made changes where necessary. The preliminary dataset was 
based on data in the 2002 National Emissions Inventory (NEI) Final 
Inventory, Version 1 (made publicly available on February 26, 2006). 
The NEI is a database that contains information about sources that emit 
criteria air pollutants, their precursors, and HAP. The NEI database 
includes estimates of annual air pollutant emissions from point, non-
point, and mobile sources in the 50 States, the District of Columbia, 
Puerto Rico, and the Virgin Islands. The EPA collects this information 
and releases an updated version of the NEI database every 3 years.
    On December 4, 2009, a CAA Section 114 Information Collection 
Request (ICR) was issued requesting information from the one facility 
in this source category. An updated dataset was created through 
incorporation of changes to the dataset from the ICR data review 
process and additional information gathered by EPA. The updated dataset 
contains information for the one facility in the source category and 
was used to conduct the risk assessment and other analyses that form 
the basis for the proposed risk and technology reviews. A copy of the 
dataset used and documentation of the risk assessment can be found in 
the docket.

[[Page 9419]]

2. Establishing the Relationship Between Actual Emissions and MACT-
Allowable Emissions Levels
    The available emissions data in the NEI and from other sources 
typically represent the estimates of mass of emissions actually emitted 
during the specified annual time period. These ``actual'' emission 
levels are often lower than the emission levels that a facility might 
be allowed to emit and still comply with the MACT standards. The 
emissions level allowed to be emitted by the MACT standards is referred 
to as the ``MACT-allowable'' emissions level. This represents the 
highest emissions level that could be emitted by the facility without 
violating the MACT standards.
    We discussed the use of both MACT-allowable and actual emissions in 
the final Coke Oven Batteries residual risk rule (70 FR 19998-19999, 
April 15, 2005) and in the proposed and final Hazardous Organic NESHAP 
(HON) residual risk rules (71 FR 34428, June 14, 2006, and 71 FR 76609, 
December 21, 2006, respectively). In those previous actions, we noted 
that assessing the risks at the MACT-allowable level is inherently 
reasonable since these risks reflect the maximum level sources could 
emit and still comply with national emission standards. But we also 
explained that it is reasonable to consider actual emissions, where 
such data are available, in both steps of the risk analysis, in 
accordance with the Benzene NESHAP. (54 FR 38044, September 14, 1989.) 
It is reasonable to consider actual emissions because sources typically 
seek to perform better than required by emission standards to provide 
an operational cushion to accommodate the variability in manufacturing 
processes and control device performance.
    As described above, the actual emissions data were compiled based 
on the NEI, information gathered from the facility and State, and 
information received in response to the ICR. To estimate emissions at 
the MACT-allowable level, we developed a ratio of MACT-allowable to 
actual emissions for each source type (i.e., the individual stacks and 
the aggregate fugitive emissions) for the one facility in the source 
category. This ratio is based on the level of control required by the 
MACT standards compared to the level of reported actual emissions and 
available information on the level of control achieved by the emissions 
controls in use. For example, if there was information to suggest that 
an emission point type was being controlled by 98 percent while the 
MACT standards required only 92 percent control, we would estimate that 
MACT-allowable emissions from that emission point type could be as much 
as 4 times higher (8 percent allowable emissions compared with 2 
percent actually emitted), and the ratio of MACT-allowable to actual 
would be 4:1 for this emission point type. After developing these 
ratios for each emission point type at the one facility in this source 
category, we next applied these ratios to the maximum chronic risk 
estimates from the inhalation risk assessment to obtain maximum risk 
estimates based on MACT-allowable emissions. The estimate of MACT-
allowable emissions for the Primary Lead Smelting source category is 
described in section V of this preamble.
3. Conducting Dispersion Modeling, Determining Inhalation Exposures, 
and Estimating Individual and Population Inhalation Risks
    Both long-term and short-term inhalation exposure concentrations 
and health risks from the source category addressed in this proposal 
were estimated using the Human Exposure Model (Community and Sector 
HEM-3 version 1.1.0). The HEM-3 performs three of the primary risk 
assessment activities listed above: (1) Conducting dispersion modeling 
to estimate the concentrations of HAP in ambient air, (2) estimating 
long-term and short-term inhalation exposures to individuals residing 
within 50 km of the modeled sources, and (3) estimating individual and 
population-level inhalation risks using the exposure estimates and 
quantitative dose-response information.
    The dispersion model used by HEM-3 is AERMOD, which is one of EPA's 
preferred models for assessing pollutant concentrations from industrial 
facilities.\6\ To perform the dispersion modeling and to develop the 
preliminary risk estimates, HEM-3 draws on three data libraries. The 
first is a library of meteorological data, which is used for dispersion 
calculations. This library includes 1 year of hourly surface and upper 
air observations for 130 meteorological stations, selected to provide 
coverage of the United States and Puerto Rico. However, in this 
instance, site-specific meteorological data for the one facility in 
this source category were supplied by the state of Missouri and used 
for the modeling. The data provided by the state of Missouri were for 
eight quarters (i.e., eight three-month periods) from April 1997 
through June 1999. To obtain one year of meteorological data, we used 
the middle portion of these data, the year 1998, in our modeling. A 
second library of United States Census Bureau census block \7\ internal 
point locations and populations provides the basis of human exposure 
calculations (Census, 2000). In addition, for each census block, the 
census library includes the elevation and controlling hill height, 
which are also used in dispersion calculations. A third library of 
pollutant unit risk factors and other health benchmarks is used to 
estimate health risks. These risk factors and health benchmarks are the 
latest values recommended by EPA for HAP and other toxic air 
pollutants. These values are available at http://www.epa.gov/ttn/atw/toxsource/summary.html and are discussed in more detail later in this 
section.
---------------------------------------------------------------------------

    \6\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \7\ A census block is generally the smallest geographic area for 
which census statistics are tabulated.
---------------------------------------------------------------------------

    In developing the risk assessment for chronic exposures, we used 
the estimated annual average ambient air concentration of each of the 
HAP emitted by each source for which we have emissions data in the 
source category. The air concentrations at each nearby census block 
centroid were used as a surrogate for the chronic inhalation exposure 
concentration for all the people who reside in that census block. We 
calculated the MIR for the one facility as the cancer risk associated 
with a lifetime (70-year period) of exposure to the maximum 
concentration at the centroid of an inhabited census block. Individual 
cancer risks were calculated by multiplying the estimated lifetime 
exposure to the ambient concentration of each of the HAP (in micrograms 
per cubic meter) by its Unit Risk Estimate (URE), which is an upper 
bound estimate of an individual's probability of contracting cancer 
over a lifetime of exposure to a concentration of 1 microgram of the 
pollutant per cubic meter of air. In general, for residual risk 
assessments, we use URE values from EPA's Integrated Risk Information 
System (IRIS). For carcinogenic pollutants without EPA IRIS values, we 
look to other reputable sources of cancer dose-response values, often 
using California Environmental Protection Agency (CalEPA) URE values, 
where available. In cases where new, scientifically credible dose-
response values have been developed in a manner consistent with EPA 
guidelines and have undergone a peer review process similar to that 
used by

[[Page 9420]]

EPA, we may use such dose response values in place of, or in addition 
to, other values, if appropriate. In this review, IRIS values were 
available for both carcinogenic pollutants (cadmium and arsenic) 
emitted by the facility in this source category, and therefore IRIS 
values were used in the assessment.
    Incremental individual lifetime cancer risks associated with 
emissions from the one source in the source category were estimated as 
the sum of the risks for each of the carcinogenic HAP (including those 
classified as carcinogenic to humans, likely to be carcinogenic to 
humans, and suggestive evidence of carcinogenic potential \8\) emitted 
by the modeled source. Cancer incidence and the distribution of 
individual cancer risks for the population within 50 km of the source 
were also estimated for the source category as part of these 
assessments by summing individual risks. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044) and the limitations of Gaussian dispersion models, 
including AERMOD.
---------------------------------------------------------------------------

    \8\ These classifications also coincide with the terms ``known 
carcinogen, probable carcinogen, and possible carcinogen,'' 
respectively, which are the terms advocated in the EPA's previous 
Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR 
33992, September 24, 1986). Summing the risks of these individual 
compounds to obtain the cumulative cancer risks is an approach that 
was recommended by the EPA's SAB in their 2002 peer review of EPA's 
NATA entitled, NATA--Evaluating the National-scale Air Toxics 
Assessment 1996 Data--an SAB Advisory, available at: http://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess risk of non-cancer health effects from chronic exposures, 
we summed the HQ for each of the HAP that affects a common target organ 
system to obtain the HI for that target organ system (or target organ-
specific HI, TOSHI). The HQ is the estimated exposure divided by the 
chronic reference value, which is either the EPA RfC, defined as ``an 
estimate (with uncertainty spanning perhaps an order of magnitude) of a 
continuous inhalation exposure to the human population (including 
sensitive subgroups) that is likely to be without an appreciable risk 
of deleterious effects during a lifetime,'' or, in cases where an RfC 
is not available, the Agency for Toxic Substances and Disease Registry 
(ATSDR) chronic Minimal Risk Level (MRL) or the CalEPA Chronic 
Reference Exposure Level (REL). The REL is defined as ``the 
concentration level at or below which no adverse health effects are 
anticipated for a specified exposure duration.''
    Screening estimates of acute exposures and risks were also 
evaluated for each of the HAP at the point of highest off-site exposure 
for each facility (i.e., not just the census block centroids) assuming 
that a person was located at this spot at a time when both the peak 
(hourly) emission rate and hourly dispersion conditions occurred. In 
general, acute HQ values were calculated using best available, short-
term dose-response value. These acute dose-response values include REL, 
Acute Exposure Guideline Levels (AEGL), and Emergency Response Planning 
Guidelines (ERPG) for 1-hour exposure durations. Notably, for HAP 
emitted from this source category, REL values were the only such dose-
response values available. As discussed below, we used conservative 
assumptions for emission rates, meteorology, and exposure location for 
our acute analysis.
    As described in the CalEPA's Air Toxics Hot Spots Program Risk 
Assessment Guidelines, Part I, The Determination of Acute Reference 
Exposure Levels for Airborne Toxicants, an acute REL value (http://www.oehha.ca.gov/air/pdf/acuterel.pdf) is defined as ``the 
concentration level at or below which no adverse health effects are 
anticipated for a specified exposure duration is termed the REL. REL 
values are based on the most sensitive, relevant, adverse health effect 
reported in the medical and toxicological literature. REL values are 
designed to protect the most sensitive individuals in the population by 
the inclusion of margins of safety. Since margins of safety are 
incorporated to address data gaps and uncertainties, exceeding the REL 
does not automatically indicate an adverse health impact.
    To develop screening estimates of acute exposures, we first 
developed estimates of maximum hourly emission rates by multiplying the 
average actual annual hourly emission rates by a factor to cover 
routinely variable emissions. We chose the factor to use based on 
process knowledge and engineering judgment and with awareness of a 
Texas study of short-term emissions variability, which showed that most 
peak emission events, in a heavily-industrialized 4-county area 
(Harris, Galveston, Chambers, and Brazoria Counties, Texas) were less 
than twice the annual average hourly emission rate. The highest peak 
emission event was 74 times the annual average hourly emission rate, 
and the 99th percentile ratio of peak hourly emission rate to the 
annual average hourly emission rate was 9.\9\ This analysis is provided 
in Appendix 4 of the Draft Residual Risk Assessment for Primary Lead 
Smelting which is available in the docket for this action. Considering 
this analysis, unless specific process knowledge or data are available 
to provide an alternate value, to account for more than 99 percent of 
the peak hourly emissions, we apply a conservative screening 
multiplication factor of 10 to the average annual hourly emission rate 
in these acute exposure screening assessments. For the Primary Lead 
Smelting source category, this factor of 10 was applied.
---------------------------------------------------------------------------

    \9\ See http://www.tceq.state.tx.us/compliance/field_ops/eer/index.html or docket to access the source of these data.
---------------------------------------------------------------------------

    In cases where all acute HQ values from the screening step were 
less than or equal to 1, acute impacts were deemed negligible and no 
further analysis was performed. In the cases where an acute HQ from the 
screening step was greater than 1, additional site-specific data were 
considered to develop a more refined estimate of the potential for 
acute impacts of concern. Ideally, we would prefer to have continuous 
measurements over time to see how the emissions vary by each hour over 
an entire year. Having a frequency distribution of hourly emission 
rates over a year would allow us to perform a probabilistic analysis to 
estimate potential threshold exceedances and their frequency of 
occurrence. Such an evaluation could include a more complete 
statistical treatment of the key parameters and elements adopted in 
this screening analysis. However, we recognize that having this level 
of data is rare, hence our use of the multiplier (i.e., factor of 10) 
approach in our screening analysis.
4. Conducting Multipathway Exposure and Risk Modeling
    The potential for significant human health risks due to exposures 
via routes other than inhalation (i.e., multipathway exposures) and the 
potential for adverse environmental impacts were evaluated in a three-
step process. In the first step, we determined whether any facilities 
emitted any HAP known to be persistent and bio-accumulative in the 
environment (PB-HAP). There are 14 PB-HAP compounds or compound classes 
identified for this screening in EPA's Air Toxics Risk Assessment 
Library (available at http://www.epa.gov/ttn/fera/risk_atra_vol1.html). They are cadmium compounds, chlordane, chlorinated 
dibenzodioxins and furans, dichlorodiphenyldichloroethylene, 
heptachlor, hexachlorobenzene,

[[Page 9421]]

hexachlorocyclohexane, lead compounds, mercury compounds, methoxychlor, 
polychlorinated biphenyls, POM, toxaphene, and trifluralin. Emissions 
of two PB HAP were identified in the emissions inventory for the 
Primary Lead Smelting source category: Lead compounds and cadmium 
compounds.
    Cadmium emissions were evaluated for potential non-inhalation risks 
and adverse environmental impacts using our recently developed 
screening scenario that was developed for use with the TRIM.FaTE model. 
This screening scenario uses environmental media outputs from the peer-
reviewed TRIM.FaTE to estimate the maximum potential ingestion risks 
for any specified emission scenario by using a generic farming/fishing 
exposure scenario that simulates a subsistence environment. The 
screening scenario retains many of the ingestion and scenario inputs 
developed for EPA's Human Health Risk Assessment Protocols (HHRAP) for 
hazardous waste combustion facilities. In the development of the 
screening scenario a sensitivity analysis was conducted to ensure that 
its key design parameters were established such that environmental 
media concentrations were not underestimated, and to also minimize the 
occurrence of false positives for human health endpoints. See Appendix 
3 of the risk assessment document for a complete discussion of the 
development and testing of the screening scenario, as well as for the 
values of facility-level de minimis emission rates developed for 
screening potentially significant multi-pathway impacts. For the 
purpose of developing de minimis emission rates for our cadmium multi-
pathway screening, we derived emission levels for cadmium at which the 
maximum human health risk would be 1-in-1 million for lifetime cancer 
risk.
    In evaluating the potential air-related multi-pathway risks from 
the emissions of lead compounds from the one facility in this source 
category, rather than developing a de minimis emission rate, we 
compared its maximum modeled 3-month average atmospheric lead 
concentration at any off-site location with the current primary 
National Ambient Air Quality Standard (NAAQS) for lead (promulgated in 
2008), which is set to a level of 0.15 micro-grams per cubic meter 
([micro]g/m\3\) based on a rolling 3-month period with a not-to-be-
exceeded form, and which will require attainment by 2016. 73 FR 66964. 
Notably, in making these comparisons, we estimated maximum rolling 3-
month ambient lead concentrations taking into account all of the 
elements of the NAAQS for lead. That is, our estimated 3-month lead 
concentrations are calculated in a manner that is consistent with the 
indicator, averaging time, and form of the NAAQS for lead, and those 
estimates are compared to the actual level of the lead NAAQS (0.15 
[mu]g/m\3\).
    The NAAQS value, a public health policy judgment, incorporated the 
Agency's most recent health evaluation of air effects of lead exposure 
for the purposes of setting a national standard. In setting this value, 
the Administrator promulgated a standard that was requisite to protect 
public health with an adequate margin of safety. We consider values 
below the level of the primary NAAQS to protect against multi-pathway 
risks because, as mentioned above, the primary NAAQS is set as to 
protect public health with an adequate margin of safety. However, 
ambient air lead concentrations above the NAAQS are considered to pose 
the potential for increased risk to public health. We consider this 
NAAQS assessment to be a refined analysis given the numerous health 
studies, detailed risk and exposure analyses, and level of external 
peer and public review that went into the development of the primary 
NAAQS for lead, combined with the site-specific dispersion modeling 
analysis performed to develop the ambient concentration estimates due 
to emissions from the one Primary Lead Processing facility being 
addressed in this RTR. It should be noted, however, that this 
comparison does not account for possible population exposures to lead 
from sources other than the one being modeled; for example, via 
consumption of water from untreated local sources or ingestion of 
locally grown food. Nevertheless, the Administrator judged that such a 
standard, would protect, with an adequate margin of safety, the health 
of children and other at-risk populations against an array of adverse 
health effects, most notably including neurological effects, 
particularly neurobehavioral and neurocognitive effects, in children. 
73 FR 67007. The Administrator, in setting the standard, also 
recognized that no evidence-or risk based bright line indicated a 
single appropriate level. Instead a collection of scientific evidence 
and other information was used to select the standard from a range of 
reasonable values. 73 FR 67006.
    We further note that comparing ambient lead concentrations to the 
NAAQS for lead, considering the level, averaging time, form and 
indicator, also informs whether there is the potential for adverse 
environmental effects. This is because the secondary lead NAAQS, which 
has the same averaging time, form, and level as the primary standard, 
was set to protect the public welfare which includes among other things 
soils, water, crops, vegetation and wildlife. CAA section 302(h). Thus, 
ambient lead concentrations above the NAAQS for lead also indicate the 
potential for adverse environmental effects.
    For additional information on the multi-pathway analysis approach, 
see the residual risk documentation as referenced in section IV.A of 
this preamble. The EPA solicits comment generally on the modeling 
approach used herein to assess air-related lead risks, and specifically 
on the use of the lead NAAQS in this analytical construct.
5. Assessing Risks Considering Emissions Control Options
    In addition to assessing baseline inhalation risks and screening 
for potential multi-pathway risks, we also estimated risks considering 
the potential emission reductions that would be achieved by the 
particular control options under consideration. The expected emissions 
reductions were applied to the specific HAP and emissions points in the 
source category dataset to develop corresponding estimates of risk 
reductions.
6. Conducting Other Risk-Related Analyses, Including Facility-Wide 
Assessments and Demographic Analyses
a. Facility-Wide Risk
    To put the source category risks in context, for our residual risk 
review, we also examine the risks from the entire ``facility,'' where 
the facility includes all HAP-emitting operations within a contiguous 
area and under common control. In other words, we examine the HAP 
emissions not only from the source category of interest, but also 
emissions of HAP from all other emission sources at the facility. In 
this rulemaking, for the sole facility in the Primary Lead Smelting 
source category, there are no other significant HAP emission sources 
present. With the exception of organic HAP sources determined to 
present insignificant risk, all HAP sources have been included in the 
risk analysis. Therefore, the facility-wide risks are the same as the 
source category risk and no separate facility-wide analysis was 
necessary.
b. Demographic Analysis
    To examine the potential for any environmental justice issues that 
might be associated with HAP emissions with this source category, we 
evaluated the

[[Page 9422]]

distributions of HAP-related cancer and non-cancer risks across 
different social, demographic, and economic groups within the 
populations living near the one facility in this source category. The 
development of demographic analyses to inform the consideration of 
environmental justice issues in EPA rulemakings is evolving. EPA offers 
the demographic analyses in this rulemaking to inform the consideration 
of potential environmental justice issues, and invites public comment 
on the approaches used and the interpretations made from the results, 
with the hope that this will support the refinement and improve the 
utility of such analyses for future rulemakings.
    For the demographic analyses, we focus on the populations within 50 
km of any facility with emission sources subject to the MACT standard 
(identical to the risk assessment). Based on the emissions for the 
source category or the facility, we then identified the populations 
that are estimated to have exposures to HAP which result in: (1) Cancer 
risks of 1-in-1 million or greater, (2) non-cancer HI of 1 or greater, 
and/or (3) ambient lead concentrations above the level of the NAAQS for 
lead. We compare the percentages of particular demographic groups 
within the focused populations to the total percentages of those 
demographic groups nationwide. The results, including other risk 
metrics, such as average risks for the exposed populations, are 
documented in a technical report in the docket for the source category 
covered in this proposal.\10\
---------------------------------------------------------------------------

    \10\ Risk and Technology Review--Analysis of Socio-Economic 
Factors for Populations Living Near Primary Lead Smelting 
Operations.
---------------------------------------------------------------------------

    The basis for the risk values used in the demographic analyses for 
the one facility subject to the Primary Lead Smelting MACT was the 
modeling results based on actual emissions levels obtained from the 
HEM-3 model described above. The risk values for each census block were 
linked to a database of information from the 2000 decennial census that 
includes data on race and ethnicity, age distributions, poverty status, 
household incomes, and education level. The Census Department 
Landview[supreg] database was the source of the data on race and 
ethnicity, and the data on age distributions, poverty status, household 
incomes, and education level were obtained from the 2000 Census of 
Population and Housing Summary File 3 (SF3) Long Form. While race and 
ethnicity census data are available at the census block level, the age 
and income census data are only available at the census block group 
level (which includes an average of 26 blocks or an average of 1,350 
people). Where census data are available at the block group level but 
not the block level, we assumed that all census blocks within the block 
group have the same distribution of ages and incomes as the block 
group.
    We focused the analysis on those census blocks where source 
category risk results show either estimated lifetime inhalation cancer 
risks above 1-in-1 million or chronic non-cancer indices above 1. In 
addition, in this case we also focused on those census blocks where 
estimated ambient lead concentrations were above the level of the lead 
NAAQS. For each of these cases, we determined the relative percentage 
of different racial and ethnic groups, different age groups, adults 
with and without a high school diploma, people living in households 
below the national median income, and for people living below the 
poverty line within those census blocks. The specific census population 
categories included:
     Total population;
     White;
     African American (or Black);
     Native Americans;
     Other races and multiracial;
     Hispanic or Latino;
     People living below the poverty line;
     Children 18 years of age and under;
     Adults 19 to 64 years of age;
     Adults 65 years of age and over;
     Adults without a high school diploma.
    It should be noted that these categories overlap in some instances, 
resulting in some populations being counted in more than one category 
(e.g., other races and multiracial and Hispanic). In addition, while 
not a specific census population category, we also examined risks to 
``Minorities,'' a classification which is defined for these purposes as 
all race population categories except white.
    The methodology and the results of the demographic analyses for 
this source category are included in the technical report available in 
the docket for this action. (Risk and Technology Review--Analysis of 
Socio-Economic Factors for Populations Living Near Primary Lead 
Smelting Operations).
7. Considering Uncertainties in Risk Assessment
    Uncertainty and the potential for bias are inherent in all risk 
assessments, including that performed for the source category addressed 
in this proposal. Although uncertainty exists, we believe the approach 
that we took, which used conservative tools and assumptions, ensures 
that our decisions are health-protective. A brief discussion of the 
uncertainties in the emissions dataset, dispersion modeling, inhalation 
exposure estimates, and dose-response relationships follows below. A 
more thorough discussion of these uncertainties is included in the risk 
assessment documentation (Draft Residual Risk Assessment for Primary 
Lead Smelting) available in the docket for this action.
a. Uncertainties in the Emissions Dataset
    Although the development of the RTR dataset involved quality 
assurance/quality control processes, the accuracy of emissions values 
will vary depending on the source of the data, the degree to which data 
are incomplete or missing, the degree to which assumptions made to 
complete the datasets are accurate, whether and to what extent errors 
were made in estimating emissions values, and other factors. The 
emission estimates considered in this analysis are annual totals 
provided by the facility that do not reflect short-term fluctuations 
during the course of a year or variations from year to year. In 
contrast, the estimates of peak hourly emission rates for the acute 
effects screening assessment were based on multiplication factors 
applied to the average annual hourly emission rates (the default factor 
of 10 was used for Primary Lead Smelting), which is intended to account 
for emission fluctuations due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    While the analysis employed EPA's recommended regulatory dispersion 
model, AERMOD, we recognize that there is uncertainty in ambient 
concentration estimates associated with any model, including AERMOD. In 
circumstances where we had to choose between various model options, 
where possible, we selected model options (e.g., rural/urban, plume 
depletion, chemistry) that provided an overestimate of ambient 
concentrations of the HAP rather than an underestimate. However, 
because of practicality and data limitation reasons, some factors 
(e.g., building downwash) have the potential in some situations to 
overestimate or underestimate ambient impacts. Despite these 
uncertainties, we believe that at off-site locations and census block 
centroids, the approach considered in the dispersion modeling analysis 
should generally yield overestimates of ambient HAP concentrations.

[[Page 9423]]

c. Uncertainties in Inhalation Exposure
    The effects of human mobility on exposures were not included in the 
assessment. Specifically, short-term mobility and long-term mobility 
between census blocks in the modeling domain were not considered.\11\ 
As a result, this simplification will likely bias the assessment toward 
overestimating the highest exposures. In addition, the assessment 
predicted the chronic exposures at the centroid of each populated 
census block as surrogates for the exposure concentrations for all 
people living in that block. Using the census block centroid to predict 
chronic exposures tends to over-predict exposures for people in the 
census block who live farther from the facility, and under-predict 
exposures for people in the census block who live closer to the 
facility. Thus, using the census block centroid to predict chronic 
exposures may lead to a potential understatement or overstatement of 
the true maximum impact for any one individual, but is an unbiased 
estimate of average risk and incidence.
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    \11\ Short-term mobility is movement from one microenvironment 
to another over the course of hours or days. Long-term mobility is 
movement from one residence to another over the course of a 
lifetime.
---------------------------------------------------------------------------

    The assessments evaluate the projected cancer inhalation risks 
associated with pollutant exposures over a 70-year period, which is the 
assumed lifetime of an individual. In reality, both the length of time 
that modeled emissions sources at facilities actually operate (i.e., 
more or less than 70 years), and the domestic growth or decline of the 
modeled industry (i.e., the increase or decrease in the number or size 
of United States facilities), will influence the future risks posed by 
a given source or source category. Depending on the characteristics of 
the industry, these factors will, in most cases, result in an 
overestimate both in individual risk levels and in the total estimated 
number of cancer cases. However, in rare cases, where a facility 
maintains or increases its emission levels beyond 70 years, residents 
live beyond 70 years at the same location, and the residents spend most 
of their days at that location, then the risks could potentially be 
underestimated. Annual cancer incidence estimates from exposures to 
emissions from these sources would not be affected by uncertainty in 
the length of time emissions sources operate. For the specific source 
in this source category we anticipate significant reduction in 
activities and emissions in the relatively near future. If this 
happens, chronic risks based on the continuation of current emission 
levels will be over estimated.
    The exposure estimates used in these analyses assume chronic 
exposures to ambient levels of pollutants. Because most people spend 
the majority of their time indoors, actual exposures may not be as 
high, depending on the characteristics of the pollutants modeled. For 
many of the HAP, indoor levels are roughly equivalent to ambient 
levels, but for very reactive pollutants or larger particles, these 
levels are typically lower. This factor has the potential to result in 
an overstatement of 25 to 30 percent of exposures.\12\
---------------------------------------------------------------------------

    \12\ U.S. EPA. National-Scale Air Toxics Assessment for 1996. 
(EPA 453/R-01-003; January 2001; page 85.)
---------------------------------------------------------------------------

    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that should 
be highlighted. The accuracy of an acute inhalation exposure assessment 
depends on the simultaneous occurrence of independent factors that may 
vary greatly, such as hourly emissions rates, meteorology, and human 
activity patterns. In this assessment, we assume that individuals 
remain for 1 hour at the point of maximum ambient concentration as 
determined by the co-occurrence of peak emissions and worst-case 
meteorological conditions. These assumptions would tend to overestimate 
actual exposures since it is unlikely that a person would be located at 
the point of maximum exposure during the time of worst-case impact.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and non-cancer effects from both chronic and acute 
exposures. Some uncertainties may be considered quantitatively, and 
others generally are expressed in qualitative terms. We note as a 
preface to this discussion a point on dose-response uncertainty that is 
brought out in EPA's 2005 Cancer Guidelines; namely, that ``the primary 
goal of EPA actions is protection of human health; accordingly, as an 
Agency policy, risk assessment procedures, including default options 
that are used in the absence of scientific data to the contrary, should 
be health protective.'' (EPA 2005 Cancer Guidelines, pages 1-7.) This 
is the approach followed here as summarized in the next several 
paragraphs. A complete detailed discussion of uncertainties and 
variabilities in dose-response relationships is given in the residual 
risk documentation which is available in the docket for this action.
    Cancer URE values used in our risk assessments are those that have 
been developed to generally provide an upper bound estimate of risk. 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical 
confidence limit).\13\ In some circumstances, the true risk could be as 
low as zero; however, in other circumstances the risk could be 
greater.\14\ When developing an upper bound estimate of risk and to 
provide risk values that do not underestimate risk, health-protective 
default approaches are generally used. To err on the side of ensuring 
adequate health-protection, EPA typically uses the upper bound 
estimates rather than lower bound or central tendency estimates in our 
risk assessments, an approach that may have limitations for other uses 
(e.g., priority-setting or expected benefits analysis).
---------------------------------------------------------------------------

    \13\ IRIS glossary (http://www.epa.gov/NCEA/iris/help_gloss.htm).
    \14\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible, and which is based on maximum 
likelihood estimates.
---------------------------------------------------------------------------

    Chronic non-cancer reference (RfC and RfD) values represent chronic 
exposure levels that are intended to be health-protective levels. 
Specifically, these values provide an estimate (with uncertainty 
spanning perhaps an order of magnitude) of a continuous inhalation 
exposure (RfC) or a daily oral exposure (RfD) to the human population 
(including sensitive subgroups) that is likely to be without an 
appreciable risk of deleterious effects during a lifetime. To derive 
values that are intended to be ``without appreciable risk,'' the 
methodology relies upon an uncertainty factor (UF) approach (U.S. EPA, 
1993, 1994) which includes consideration of both uncertainty and 
variability. When there are gaps in the available information, UF are 
applied to derive reference values that are intended to protect against 
appreciable risk of deleterious effects. The UF are commonly default 
values,\15\ e.g., factors

[[Page 9424]]

of 10 or 3, used in the absence of compound-specific data; where data 
are available, UF may also be developed using compound-specific 
information. When data are limited, more assumptions are needed and 
more UF are used. Thus, there may be a greater tendency to overestimate 
risk in the sense that further study might support development of 
reference values that are higher (i.e., less potent) because fewer 
default assumptions are needed. However, for some pollutants, it is 
possible that risks may be underestimated.
---------------------------------------------------------------------------

    \15\ According to the NRC report, Science and Judgment in Risk 
Assessment (NRC, 1994) ``[Default] options are generic approaches, 
based on general scientific knowledge and policy judgment, that are 
applied to various elements of the risk assessment process when the 
correct scientific model is unknown or uncertain.'' The 1983 NRC 
report, Risk Assessment in the Federal Government: Managing the 
Process, defined default option as ``the option chosen on the basis 
of risk assessment policy that appears to be the best choice in the 
absence of data to the contrary'' (NRC, 1983a, p. 63). Therefore, 
default options are not rules that bind the Agency; rather, the 
Agency may depart from them in evaluating the risks posed by a 
specific substance when it believes this to be appropriate. In 
keeping with EPA's goal of protecting public health and the 
environment, default assumptions are used to ensure that risk to 
chemicals is not underestimated (although defaults are not intended 
to overtly overestimate risk). See EPA, 2004, An Examination of EPA 
Risk Assessment Principles and Practices, EPA/100/B-04/001 available 
at: http://www.epa.gov/osa/pdfs/ratf-final.pdf.
---------------------------------------------------------------------------

    While collectively termed ``UF,'' these factors account for a 
number of different quantitative considerations when using observed 
animal (usually rodent) or human toxicity data in the development of 
the RfC. The UF are intended to account for: (1) Variation in 
susceptibility among the members of the human population (i.e., inter-
individual variability); (2) uncertainty in extrapolating from 
experimental animal data to humans (i.e., interspecies differences); 
(3) uncertainty in extrapolating from data obtained in a study with 
less-than-lifetime exposure (i.e., extrapolating from sub-chronic to 
chronic exposure); (4) uncertainty in extrapolating the observed data 
to obtain an estimate of the exposure associated with no adverse 
effects; and (5) uncertainty when the database is incomplete or there 
are problems with the applicability of available studies. Many of the 
UF used to account for variability and uncertainty in the development 
of acute reference values are quite similar to those developed for 
chronic durations, but they more often use individual UF values that 
may be less than 10. UF are applied based on chemical-specific or 
health effect-specific information (e.g., simple irritation effects do 
not vary appreciably between human individuals, hence a value of 3 is 
typically used), or based on the purpose for the reference value (see 
the following paragraph). The UF applied in acute reference value 
derivation include: (1) Heterogeneity among humans; (2) uncertainty in 
extrapolating from animals to humans; (3) uncertainty in lowest 
observed adverse effect (exposure) level to no observed adverse effect 
(exposure) level adjustments; and (4) uncertainty in accounting for an 
incomplete database on toxic effects of potential concern. Additional 
adjustments are often applied to account for uncertainty in 
extrapolation from observations at one exposure duration (e.g., 4 
hours) to derive an acute reference value at another exposure duration 
(e.g., 1 hour).
    As further discussed below, there is no RfD or other comparable 
chronic health benchmark value for lead compounds. Thus, to address 
multipathway human health and environmental risks associated with 
emissions of lead from this facility, ambient lead concentrations were 
compared to the NAAQS for lead. In developing the NAAQS for lead, EPA 
considered human health evidence reporting adverse health effects 
associated with lead exposure, as well as an EPA conducted multipathway 
risk assessment that applied models to estimate human exposures to air-
related lead and the associated risk (73 FR 66979). EPA also explicitly 
considered the uncertainties associated with both the human health 
evidence and the exposure and risk analyses when developing the NAAQS 
for lead. For example, EPA considered uncertainties in the relationship 
between ambient air lead and blood lead levels (73 FR 66974), as well 
as uncertainties between blood lead levels and loss of IQ points in 
children (73 FR 66981).
    In considering the evidence and risk analyses and their associated 
uncertainties, the EPA Administrator noted his view that there is no 
evidence- or risk-based bright line that indicates a single appropriate 
level. Instead, he noted, there is a collection of scientific evidence 
and judgments and other information, including information about the 
uncertainties inherent in many relevant factors, which needs to be 
considered together in making this public health policy judgment and in 
selecting a standard level from a range of reasonable values (73 FR 
66998). In so doing, the Administrator decided that, a level for the 
primary lead standard of 0.15 [mu]g/m\3\, in combination with the 
specified choice of indicator, averaging time, and form, is requisite 
to protect public health, including the health of sensitive groups, 
with an adequate margin of safety (73 FR 67006). A thorough discussion 
of the health evidence, risk and exposure analyses, and their 
associated uncertainties can be found in EPA's final rule revising the 
lead NAAQS (73 FR 66970-66981, November 12, 2008).
    We also note the uncertainties associated with the health-based 
(i.e., primary) NAAQS are likely less than the uncertainties associated 
with dose-response values developed for many of the other HAP, 
particularly those HAP for which no human health data exist. In 1988, 
EPA's IRIS program reviewed the health effects data regarding lead and 
its inorganic compounds and determined that it would be inappropriate 
to develop an RfD for these compounds, saying, ``A great deal of 
information on the health effects of lead has been obtained through 
decades of medical observation and scientific research. This 
information has been assessed in the development of air and water 
quality criteria by the Agency's Office of Health and Environmental 
Assessment (OHEA) in support of regulatory decision-making by the 
Office of Air Quality Planning and Standards (OAQPS) and by the Office 
of Drinking Water (ODW). By comparison to most other environmental 
toxicants, the degree of uncertainty about the health effects of lead 
is quite low. It appears that some of these effects, particularly 
changes in the levels of certain blood enzymes and in aspects of 
children's neurobehavioral development, may occur at blood lead levels 
so low as to be essentially without a threshold. The Agency's RfD Work 
Group discussed inorganic lead (and lead compounds) at two meetings 
(07/08/1985 and 07/22/1985) and considered it inappropriate to develop 
an RfD for inorganic lead.'' EPA's IRIS assessment for Lead and 
compounds (inorganic) (CASRN 7439-92-1), http://www.epa.gov/iris/subst/0277.htm.
    We also note that because of the multi-pathway, multi-media impacts 
of lead, the risk assessment supporting the NAAQS considered direct 
inhalation exposures and indirect air-related multi-pathway exposures 
from industrial sources like primary and secondary lead smelting 
operations. It also considered background lead exposures from other 
sources (like contaminated drinking water and exposure to lead-based 
paints). In revising the NAAQS for lead, we note that the Administrator 
placed more weight on the evidence-based framework and less weight on 
the results from the risk assessment, although he did find the risk 
estimates to be roughly consistent with and generally supportive of the 
evidence-based framework applied in the NAAQS determination. 73 FR 
67004. Thus, when revising the NAAQS for lead to protect public health 
with an adequate margin of safety, EPA considered both

[[Page 9425]]

the health evidence and the risk assessment, albeit to different 
extents.
    In addition to the uncertainties discussed above with respect to 
chronic, cancer, and the lead NAAQS reference values, there are also 
uncertainties associated with acute reference values. Not all acute 
reference values are developed for the same purpose, and care must be 
taken when interpreting the results of an acute assessment of human 
health effects relative to the reference value or values being 
exceeded. Where relevant to the estimated exposures, the lack of short-
term dose-response values at different levels of severity should be 
factored into the risk characterization as potential uncertainties.
    Although every effort is made to identify peer-reviewed reference 
values for cancer and non-cancer effects for all pollutants emitted by 
the sources included in this assessment, some hazardous air pollutants 
continue to have no peer-reviewed reference values for cancer or 
chronic non-cancer or acute effects. Since exposures to these 
pollutants cannot be included in a quantitative risk estimate, an 
understatement of risk for these pollutants at environmental exposure 
levels is possible.
    Additionally, chronic reference values for several of the compounds 
included in this assessment are currently under EPA IRIS review (e.g., 
cadmium and nickel), and revised assessments may determine that these 
pollutants are more or less potent than the current value. We may re-
evaluate residual risks for the final rulemaking if, as a result of 
these reviews, a dose-response metric changes enough to indicate that 
the risk assessment supporting this notice may significantly understate 
human health risk.
e. Uncertainties in the Multipathway and Environmental Effects 
Assessment
    We generally assume that when exposure levels are not anticipated 
to adversely affect human health, they also are not anticipated to 
adversely affect the environment. For each source category, we 
generally rely on the site-specific levels of PB-HAP emissions to 
determine whether a full assessment of the multi-pathway and 
environmental effects is necessary. For PB-HAPS other than lead (i.e., 
cadmium), site-specific PB-HAP emission levels were far below levels 
which would trigger a refined assessment of multi-pathway impacts, thus 
we are confident that these types of impacts are insignificant for the 
one facility in this source category.
f. Uncertainties in the Facility-Wide Risk Assessment
    We did not conduct a separate facility-wide risk assessment for 
this proposal because all of the HAP emission sources at the one 
facility subject to the MACT are covered by the MACT standard under 
review. Thus, the level of the facility-wide HAP emissions is the same 
as the level of emissions from the emissions sources subject to the 
MACT standard under review.
g. Uncertainties in the Demographic Analysis
    Our analysis of the distribution of risks across various 
demographic groups is subject to the typical uncertainties associated 
with census data (e.g., errors in filling out and transcribing census 
forms), as well as the additional uncertainties associated with the 
extrapolation of census-block group data (e.g., income level and 
education level) down to the census block level.

B. How did we perform the technology review?

    Our technology review is focused on the identification and 
evaluation of developments in practices, processes, and control 
technologies. If a review of available information identifies such 
developments, then we conduct an analysis of the technical feasibility 
of these developments, along with the impacts (costs, emission 
reductions, risk reductions, etc.). We then make a decision on whether 
it is necessary to amend the regulation to require any identified 
developments.
    Based on specific knowledge of the primary lead smelting source 
category, we began by identifying known developments in practices, 
processes, and control technologies. For the purpose of this exercise, 
we considered any of the following to be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during MACT development;
     Any improvements in add-on control technology or other 
equipment (that was identified and considered during MACT development) 
that could result in significant additional emission reduction;
     Any work practice or operational procedure that was not 
identified and considered during MACT development; and
     Any process change or pollution prevention alternative 
that could be broadly applied that was not identified and considered 
during MACT development.
    In addition to looking back at practices, processes, or control 
technologies reviewed at the time we developed the MACT standards, we 
reviewed a variety of sources of data to aid in our evaluation of 
whether there were additional practices, processes, or controls to 
consider. One of these sources of data was subsequent air toxics rules. 
Since the promulgation of the MACT standard for the primary lead 
smelting source category addressed in this proposal, EPA has developed 
air toxics regulations for a number of additional source categories. We 
reviewed the regulatory requirements and/or technical analyses 
associated with these subsequent regulatory actions to identify any 
practices, processes, and control technologies considered in these 
efforts that could possibly be applied to emission sources in the 
primary lead smelting source category.
    We also consulted EPA's RACT/BACT/LAER Clearinghouse (RBLC). The 
terms ``RACT,'' ``BACT,'' and ``LAER'' are acronyms for different 
program requirements under the CAA provisions addressing the national 
ambient air quality standards. Control technologies, classified as RACT 
(Reasonably Available Control Technology), BACT (Best Available Control 
Technology), or LAER (Lowest Achievable Emission Rate) apply to 
stationary sources depending on whether the sources are existing or 
new, and on the size, age, and location of the facility. BACT and LAER 
(and sometimes RACT) are determined on a case-by-case basis, usually by 
state or local permitting agencies. EPA established the RBLC to provide 
a central database of air pollution technology information (including 
technologies required in source-specific permits) to promote the 
sharing of information among permitting agencies and to aid in 
identifying future possible control technology options that might apply 
broadly to numerous sources within a category or apply only on a 
source-by-source basis. The RBLC contains over 5,000 air pollution 
control permit determinations that can help identify appropriate 
technologies to mitigate many air pollutant emission streams. We 
searched this database to determine whether any practices, processes, 
or control technologies are included for the types of processes covered 
by the primary lead smelting MACT.
    We also requested information from the facility regarding 
developments in practices, processes, or control technology. Finally, 
we reviewed other information sources, such as state or

[[Page 9426]]

local permitting agency databases and industry-supported databases.

C. Overview of the Source Category and MACT Standards

1. Source Category and MACT Standard
    The National Emission Standard for Primary Lead Smelting (or MACT 
rule) was promulgated on June 4, 1999 (64 FR 30194) and codified at 40 
CFR part 63, subpart TTT. As promulgated in 1999, the MACT standard 
applies to affected sources of HAP at primary lead smelters.\16\ The 
MACT defines ``Primary lead smelters'' as ``any facility engaged in the 
production of lead metal from lead sulfide ore concentrates through the 
use of pyrometallurgical techniques.'' 40 CFR 63.1542. The MACT 
standard for the Primary Lead Smelting source category does not apply 
to secondary lead smelters, lead remelters, or lead refiners (Sec.  
63.1541). Today there is one facility (The Doe Run Company in 
Herculaneum, Missouri) operating that is subject to the MACT standards 
(See Section V.A. below).
---------------------------------------------------------------------------

    \16\ As provided above in section III(C)(3), we are proposing to 
change the standard to apply to Primary Lead Processors.
---------------------------------------------------------------------------

    At the time of promulgation of the Primary Lead Smelting MACT rule, 
there were three operating lead smelters. Due to economic pressures 
(decreased market demand for lead) and regulatory pressures, two of the 
lead smelting facilities subject to the MACT standard have since been 
permanently closed, leaving one primary lead smelter currently 
operating in the United States. No new primary lead smelters have been 
built in the last 20 years, and no new primary lead processing 
facilities using pyrometallurgical techniques are anticipated in the 
foreseeable future. The one operating lead smelter is not collocated 
with other sources of HAP emissions.
    Lead is used to make various construction and consumer products 
such as batteries, paint, glass, piping, and filler. Lead sulfide (PbS) 
ore concentrates are the main feed material to primary lead smelters. 
The primary lead smelting process consists of lead sulfide concentrate 
storage and handling, sintering of ore concentrates, sinter crushing 
and handling, smelting of sinter to lead metal, drossing (i.e., 
removing the solid oxide deposits), refining and alloying of lead 
metal, and smelting of the drosses.
    HAP are emitted from primary lead smelting as process emissions 
(stack), process fugitive emissions, and fugitive dust emissions. 
Process emissions are associated with the exhaust gases from sinter 
machines and blast and dross furnaces. HAP expected in process 
emissions are metals (mostly lead compounds, but also some arsenic, 
cadmium, and other metals) and also may include small amounts of 
organic compounds that result from incomplete combustion of coke, which 
is charged along with sinter to the blast furnace. Process fugitive 
emissions occur at various points during the smelting process (such as 
during charging and tapping of furnaces) and the only HAP emitted are 
metal HAP. Fugitive dust emissions result from the entrainment of dust 
due to material handling, vehicle traffic, and wind erosion from 
storage piles and the only HAP emitted are metal HAP.
    The MACT standard (40 CFR part 63, subpart TTT) applies to process 
emissions (stack) from sinter machines, blast furnaces, and dross 
furnaces; process fugitive emissions from sinter, blast furnace, 
drossing and refining processes, concentrate handling, and locations 
around such processes; and fugitive dust emission sources, such as 
roadways, storage piles and the plant yard. Process emissions of lead 
compounds from sinter machines, blast furnaces, and dross furnaces, and 
process fugitive emissions from the blast furnace and dross furnace 
charging, blast furnace and dross furnace tapping, and the sinter 
machine (charging, discharging, crushing, and sizing) are limited to 
500 grams (g) of lead emissions per mega gram (Mg) of lead produced 
(500 g/Mg), which is equal to 1.0 pound (lb) of lead emissions per ton 
of lead produced (1 lb/ton). 40 CFR 63.1542(a). A plant-wide limit 
format was used for MACT because it was consistent with SIPs, the 
commingling of exhaust gases from processes to a single stack made it 
impossible to set limits for individual sources, it gave the facilities 
more flexibility in complying with the standard, and it promoted 
pollution prevention by giving each facility the ability to meet the 
emission limit through any combination of source reduction and control 
technology options. (63 FR 19208).
    In addition to being subject to the plant-wide emission limit of 
the standard, process fugitive emissions must be captured by a hood and 
ventilated to a baghouse or equivalent control device and the hood 
design and ventilation rate must be consistent with American Conference 
of Governmental Industrial Hygienists recommended practices. 40 CFR 
63.1543(b). In addition, the sinter machine area fugitives must be 
enclosed in a building that is ventilated to a baghouse at a rate that 
maintains a positive in-draft through any doorway opening. 40 CFR 
63.1543(c). The MACT standard also requires the use of bag leak 
detection systems for continuous monitoring of baghouses. 40 CFR 
63.1547(c)(9). For fugitive dust sources, as defined in 40 CFR 63.1544, 
the MACT standard requires that the owner or operator prepare and 
operate at all times according to a standard operating procedures (SOP) 
manual. The SOP manual must describe in detail the measures used to 
control fugitive dust emissions from plant roadways, material storage 
and handling areas, sinter machine areas, blast and dross furnace 
areas, and refining and casting operations areas. Existing work 
practice manual(s) that describe the measures in place to control 
fugitive dust sources required as part of a state implementation plan 
for lead satisfy this requirement.
2. MACT as it Applies to Doe Run Company Primary Lead Smelter, 
Herculaneum, Missouri
    As stated above, the Doe Run Smelter in Herculaneum, Missouri, is 
the sole remaining lead processing facility in the United States 
subject to the MACT. The 1999 MACT rule established a plant-wide lead 
emission limit of 1 lb of lead per ton of lead produced that applies to 
the aggregation of emissions from specific sources that discharge from 
air pollution control devices. Compliance with the plant-wide emission 
limit is demonstrated by annual stack testing. The rule lists nine 
sources as subject to the plant-wide limit including: (1) Sinter 
machine, (2) blast furnace, (3) dross furnace, (4) dross furnace 
charging location, (5) blast furnace and dross furnace tapping 
location, (6) sinter machine charging location, (7) sinter machine 
discharge end, (8) sinter crushing and sizing equipment, and (9) sinter 
machine area. At the Doe Run plant, lead emissions from these sources 
are controlled by baghouses that exhaust through two stacks. The 
sources in the sinter operation, the blast furnace, and the dross 
furnace are controlled by three baghouses all of which discharge 
through one emission point, which is designated as the main stack. The 
building that houses the blast furnace and dross kettles is vented to a 
separate baghouse (7) which discharges through a separate 
stack, designated as the furnace area stack.
    Under the 1999 MACT rule, all other sources of process fugitive and 
fugitive dust emissions are required to follow work practice standards 
detailed in the plant's standard operating procedures (SOP) manual.
    The HAP emitted in the largest quantities from the Doe Run facility 
are

[[Page 9427]]

lead compounds, which account for over 99 percent of the total HAP 
emissions by mass. The remaining HAP emissions are arsenic, antimony, 
cadmium, cobalt, nickel and trace organic HAP. Negligible levels of 
organic HAP are also emitted from natural gas-fired space heating at 
the facility and the incomplete combustion of coke in the blast 
furnace. Further discussions of the emission profile for this facility 
is included in the Technical Support Document in the docket.
3. Missouri SIP and the Lead NAAQS as They Apply to Doe Run Company, 
Herculaneum, Missouri
    In addition to the MACT standard, the Doe Run Company's primary 
lead smelter in Herculaneum, Missouri is subject to a SIP for the 
purpose of attaining and maintaining the lead NAAQS.\17\ The current 
SIP, which was approved in 2002, addresses the former lead ambient air 
concentration limit of 1.5 [mu]g/m\3\ NAAQS. In addition, the 2007 SIP 
submittal from the State includes requirements addressing lead 
emissions from the Doe Run facility and can be found at http://www.dnr.mo.gov/env/apcp/docs/2009drh-leadsip.pdf.
---------------------------------------------------------------------------

    \17\ EPA most recently approved the Missouri SIP for Herculaneum 
in 2002 (67 FR 18497, April 16, 2002). Missouri Department of 
Natural Resources (MDNR) substantially revised the requirements for 
the smelter in 2007. EPA has proposed approval of this revision, but 
has not yet taken final action.
---------------------------------------------------------------------------

    In 2008, EPA revised the lead NAAQS from 1.5 [mu]g/m\3\ to 0.15 
[mu]g/m\3\. In November 2010, EPA identified or ``designated'' several 
areas as not meeting the lead NAAQS. These ``nonattainment'' 
designations include portions of Jefferson County, Missouri surrounding 
the Doe Run facility. Missouri is required by the Act to take steps to 
further control pollution in this area, and to detail these steps in a 
revision to the SIP. The revised SIP is due to EPA within eighteen 
months after the effective date of the designation, or by June 2012, 
and attainment of the NAAQS should be achieved by 2016.
    The SIP and the pending 2007 SIP submittal contain specific 
measures to be implemented by the Doe Run plant to reduce lead 
emissions. The State of Missouri revised the control requirements for 
the Doe Run facility in 2001 and 2007, requiring numerous emissions-
reducing measures and improvements to add-on control devices, 
processes, and work practices.\18\ These included improvements to 
existing emission control technology, adding or upgrading enclosures, 
process changes and limitations, and work practices. These requirements 
are summarized below.
---------------------------------------------------------------------------

    \18\ EPA most recently approved the Missouri SIP for Herculaneum 
in 2002 (67 FR 18497, April 16, 2002). MDNR substantially revised 
the requirements for the smelter in 2007. EPA has proposed approval 
of this revision, but has not yet taken final action.
---------------------------------------------------------------------------

    Point Source Requirements--As required under the SIP, lead 
emissions from the refining kettles and refining building emissions 
must be captured and vented to baghouses. Doe Run implemented these 
controls and vents the emissions to baghouses 8 and 9 
and the exhaust from the baghouse 9 is combined with baghouse 
7 exhaust and vented to a common stack. Although the MACT 
standard does not require Doe Run to do so, it has included emissions 
from refining Baghouses 8 and 9 in their 
demonstrations of compliance with the MACT plant-wide lead emission 
limit.
    Under the 2007 SIP submittal, Doe Run was required to make 
improvements to existing baghouse controls including the installation 
of pleated filters and lowering the air-to-cloth ratio for baghouses, 
increased ventilation and improved ventilation hoods at the blast 
furnace, and using reverse flow technology for baghouse cleaning. The 
2007 SIP submittal also required the installation of enclosures and/or 
partial enclosures for unloading ore concentrate, sinter storage, and 
the sides of the sinter machine (which will be evacuated to a 
baghouse).
    Process Requirements--Process changes to reduce emissions required 
by the SIP included a process control system for the injection of air 
through the blast furnace tuyeres located at the bottom of the blast 
furnace, limitations on individual process and overall plant 
throughputs, and limiting specific operations to only certain times of 
the day when the impact on ambient air concentrations is less. The SIP 
also stipulates that emissions from malfunctions will be reduced by 
alarms that sound when the baghouse fan malfunctions, an interlock 
system to restrict air flow into the blast furnace when the baghouse is 
not operating properly, and cameras for the dross and refinery kettles 
to detect kettle failure (i.e., when a plume of smoke is detected from 
the stack, the kettle burner can be immediately shut off and the 
problem corrected).
    Fugitive Dust Requirements--Under both the current SIP and the 2007 
SIP submittal, work practices are required to reduce fugitive dust 
emissions. Requirements include road watering and automatic sprinklers, 
using new regenerative sweepers to remove dust from paved surfaces to 
reduce emissions from traffic, maintaining a minimum water content 
percentage for ore concentrate and for baghouse dust that is loaded 
into railcars, and inspecting the siding that encloses buildings 
(followed by prompt repairs if needed).
    Missouri requires Doe Run to report all metal HAP emissions 
annually based on a speciation analysis that was performed.\19\ The 
state also requires an annual emissions inventory based on the stack 
tests for the point discharges and AP-42 or facility-specific emission 
factors for fugitive emissions.
---------------------------------------------------------------------------

    \19\ Doe Run Company submits annual emissions inventories to 
MDNR that report speciated metals using speciation factors for each 
metal/source derived in the late 1990s through emissions testing.
---------------------------------------------------------------------------

    As a result of the implementation of the emission control 
requirements in the currently approved 2002 SIP, and the additional 
requirements adopted by the state, as discussed above, the Doe Run 
facility has achieved a significant reduction of lead and metal HAP 
emissions since 2000 through a combination of reduced production levels 
and improved emissions controls. Based on emissions inventory data 
submitted to the Missouri Department of Natural Resources (DNR), total 
HAP emissions have been reduced from an estimated 140 tons in 2000 to 
20 tons in 2008, and the majority of the 20 tons are lead compound 
emissions. The 2008 reported emissions reflect implementation of all 
emission controls stipulated in the 2002 SIP and the 2007 SIP revision.
4. Other Federal and State Actions Affecting Doe Run Company
    More recently, the 2008 revision to the lead NAAQS has resulted in 
Doe Run Company deciding that it is not feasible for the facility to 
reduce emissions further to the level necessary to meet the newly 
revised NAAQS without closure of the current smelting operations. As a 
result of past and ongoing regulatory compliance issues at the 
facility, the facility has entered into a consent decree with U.S. EPA 
Region VII and the State of Missouri. Under the consent decree, the 
facility will, among other things, close the existing smelter operation 
and remediate the site to an agreed-upon level. The consent decree 
requires that all support operations for the smelter cease by December 
31, 2013 and that the blast furnace cease operations by April 1, 2014. 
Remediation of the site is required to commence following approval of a 
plan to be submitted to EPA in January 2013. Under the consent decree, 
the existing refining, casting and alloying operations

[[Page 9428]]

will be allowed to continue operation. Notice of the consent decree was 
published for public comment on October 15, 2010, (75 FR 63506). Once 
finalized, the consent decree is federally enforceable among the 
parties.
    Prior to closure of the current smelter, the Doe Run Company may 
build and bring to full operation a new hydrometallurgical process that 
will produce lead from lead sulfide ore, potentially adjacent to the 
current smelter. The hydrometallurgical process uses chemical reactions 
involving fluboric acid which allows recovery of lead metal through 
leaching, electrowinning, and co-product treatment processes. Some of 
the lead from the new process is likely to undergo further processing 
at the existing refinery, primarily for remelting/casting purposes. 
Based on limited data from a demonstration project, Doe Run expects 
that lead emissions from the hydrometallurgical process will be 
minimal.

V. Analyses Results and Proposed Decisions

    This section of the preamble provides a description of the dataset 
used in the RTR analysis, the results of our RTR for the source 
category, and our proposed decisions concerning changes to the Primary 
Lead Smelting MACT standard. As noted previously, all references to 
lead emissions in this proposal means ``lead compounds,'' which is the 
regulated HAP under CAA section 112. All reference to lead production 
means the production of element lead.

A. What data were used in our risk analyses?

    For the Primary Lead Smelting source category, we compiled a 
preliminary dataset using readily available information, reviewed the 
data, and made changes where necessary. The preliminary dataset was 
based on data in the 2002 National Emissions Inventory (NEI) Final 
Inventory, Version 1 (made publicly available on February 26, 2006), 
and the 2005 National Emissions Inventory (NEI), version 2.0 (made 
publicly available in October 2008). The 2005 NEI was updated to 
develop the 2005 National Air Toxics Assessment (NATA) Inventory. NATA 
inventory updates for the primary lead smelting category included SIP 
data provided by the state of MO to EPA. The 2005 NATA inventory was 
used with updated 2008 data received in an Information Collection 
Request (ICR) response from the Doe Run facility. The NEI is a database 
that contains information about sources that emit criteria air 
pollutants, their precursors, and HAP. The NEI database includes 
estimates of annual air pollutant emissions from point and volume 
sources, emission release characteristic data such as emission release 
height, temperature, velocity, and location latitude/longitude 
coordinates. We reviewed the NEI datasets, checked geographic 
coordinates, and made changes based on available information. We also 
reviewed the emissions and other data to identify data anomalies that 
could affect risk estimates.
    The risk assessment was based on estimates of the actual emissions 
and allowable emissions. The estimates of actual emissions were for the 
year 2008 and were based on data from the ICR along with data from our 
NEI dataset. These estimates included both stack and fugitive emission 
sources. Fugitive dust sources include material handling (concentrate, 
sinter, fume and dross), plantwide resuspension (roadways, storage 
piles and plant yard) and other miscellaneous sources (vents and heat 
stacks). The material handling sources contribute approximately 84 
percent of the total fugitive dust emissions, while plantwide 
resuspension and miscellaneous sources contribute approximately 11 and 
5 percent, respectively. The estimates of allowable emissions were 
calculated using production data from the ICR response combined with 
the current emissions limits in the MACT standard.
    Lead compounds account for about 99 percent of the HAP emissions 
from the source category, or about 20 tons in 2008. The facility also 
reported small emissions of five other metal HAP, and trace levels of 
25 organic HAP.
    The emissions data, calculations and risk assessment inputs for the 
Primary Lead Smelting source category are described further in the 
Technical Support Document for this action which is available in the 
docket for this proposed rulemaking.
    We used the 2008 production information as the basis for 
calculating the MACT allowable ratio (allowable to actual) because the 
2008 emissions are the most recent reported emissions that also reflect 
implementation of the requirements of the 2007 SIP revision. For more 
information on the ratio of actual to MACT-allowable emissions, see the 
Technical Support Document in the docket for this action describing the 
emission data information and estimation of MACT-allowable emission 
levels and associated risks and impacts.

B. What are the results of the risk assessments and analyses?

    For the Primary Lead Smelting source category, we conducted an 
inhalation risk assessment for all HAP emitted. We also conducted a 
multi-pathway analysis for cadmium and lead. With respect to lead, we 
used the recently-promulgated lead NAAQS to evaluate the potential for 
multi-pathway and environmental effects. Furthermore, we conducted a 
demographic analysis of population risks. Details of the risk 
assessments and additional analyses can be found in the residual risk 
documentation referenced in section IV.A of this preamble, which is 
available in the docket for this action.
1. Inhalation Risk Assessment Results
    Table 3 provides an overall summary of the results of the 
inhalation risk assessment.

                                            Table 3--Primary Lead Smelting Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
   Maximum individual cancer risk  (in 1                                                   Maximum chronic non-cancer  TOSHI \2\
               million) \1\                       Estimated         Estimated annual   --------------------------------------------   Maximum off-site
-------------------------------------------  population at risk     cancer incidence                                                 refined acute  non-
  Actual  emissions   Allowable  emissions    >= 1-in-1 million     (cases per year)      Actual  emissions   Allowable  emissions      cancer HQ \3\
        level                 level                                                             level                 level
--------------------------------------------------------------------------------------------------------------------------------------------------------
               30                    30                 4,900                0.0008                     1                     1                   0.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated maximum individual excess lifetime cancer risk.
\2\ Maximum TOSHI. The target organ with the highest TOSHI for the Primary Lead Smelting source category is the kidney.
\3\ The maximum acute HQ value shown uses the only available acute dose-response value for arsenic, which is the REL. See section IV.A of this preamble
  for explanation of acute dose-response values.


[[Page 9429]]

    The results of the chronic inhalation cancer risk assessment 
indicate that, based on estimates of actual emissions from the base 
year 2008, the maximum individual lifetime cancer risk could be as high 
as 30-in-1 million with fugitive dust emissions of cadmium dominating 
the risk. The total estimated cancer incidence from this source 
category based on actual emission levels is 0.0008 excess cancer cases 
per year or one case in every 1,250 years. Approximately 200 people 
were estimated to have cancer risks above 10-in-1 million and 
approximately 4,900 people were estimated to have cancer risks above 1-
in-1 million. When considering the maximum levels of emissions allowed 
under the current MACT standard, the MIR remains 30-in-1 million. The 
MIR remains the same since the fugitive dust emissions are governed by 
work practices, which under Sec.  63.1544 are defined as the measures 
that will be ``put into place to control fugitive dust emissions.'' 
Thus, the actual emissions, which reflect the measures that have been 
put in place, should be equivalent to the allowable emissions.
    The maximum chronic noncancer TOSHI value is 1, with fugitive 
emissions of cadmium dominating those impacts. When considering MACT 
allowable emissions, the maximum chronic noncancer TOSHI value remains 
1 since, for the reasons provided above, MACT-allowable fugitive 
emissions are equal to actual fugitive emissions.
    Based on the acute REL value for arsenic, an off-site screening-
level acute HQ value from this facility could be as high as 6. However, 
the emissions factor of 10 times the average hourly emissions rate is 
not appropriate in this instance, given that fugitive emissions are 
minimized during the meteorological conditions associated with the 
worst-case short-term impacts (i.e., during low-wind, stable 
atmospheric conditions). Thus, we refined the assessment and estimated 
a maximum off-site HQ value of 0.6.
    The results of a multipathway screening analysis for cadmium 
emissions from this facility were well below the de minimis emission 
rate that would indicate a non-negligible risk of adverse health 
effects from multipathway exposures. We estimate the specific 
multipathway de minimis emission rate for cadmium to be 0.65 TPY and 
only 0.1 TPY is emitted from the one facility in this source category. 
Thus, there appears to be little, if any, multipathway risk associated 
with cadmium emissions from this facility.
    In evaluating the potential multi-pathway risks from emissions of 
lead compounds, we compared modeled maximum 3-month rolling average 
atmospheric concentrations with the NAAQS for lead. Table 4 presents 
the results of our lead impact analysis broken down by emission point 
considering actual 2008 emissions as well as the maximum emissions of 
lead that the MACT standard would have allowed based on production 
rates for calendar year 2008. For purposes of our analysis, we 
determined separately the risk from each of the types or processes/
emissions sources regulated by the current MACT, with one exception. 
Under the MACT, emissions from the refining and casting area were 
considered fugitive emissions subject to work practice standards under 
Sec.  63.1544. Since then, pursuant to requirements that the 2002 State 
SIP adopted for purposes of meeting the 1.50 [mu]g/m\3\ lead NAAQS, Doe 
Run enclosed the refining and casting area and vents those emissions to 
the refinery stacks. We considered these stack emissions separate from 
the fugitive dust emissions. Thus, the four emission process/sources we 
evaluated for risk were: (1) The main stack, (2) the furnace area 
stack, (3) the refinery stack, and (4) fugitive emissions.
    The analysis indicates that under both actual 2008 or MACT 
allowable emission scenarios, emissions from the main stack do not 
result in lead levels above the NAAQS within the 50 km radius that was 
modeled. This is likely due to the height of the stack (500 feet), 
which would result in broader and further dispersal of lead emissions. 
However, results of the analysis did indicate that modeled ambient air 
lead concentrations resulting from this facility's fugitive dust 
emissions could exceed the NAAQS for lead by as much as 50-fold at the 
property boundary based on both actual and allowable emissions. 
Moreover, results indicate that modeled emissions from the furnace area 
stack could result in NAAQS exceedances under both actual 2008 and 
MACT-allowable emissions scenarios. In addition, the actual estimated 
emissions from the refining stacks, which were put into place based on 
requirements adopted by the State for purposes of the SIP, could result 
in NAAQS exceedances. We were unable to calculate a ``MACT allowable'' 
emission level for the refinery emissions, which under the MACT are 
included as fugitive emissions. This analysis also indicates that 
within 50 km of this facility, approximately 1,900 people could be 
exposed to ambient air lead concentrations exceeding the level of the 
NAAQS for lead.
    As mentioned above, to evaluate the potential for adverse 
environmental effects, we also compared maximum 3-month rolling average 
atmospheric concentrations with the current secondary NAAQS for lead, 
which is the same as the primary standard. Thus, the analyses presented 
in Table 4 also indicate the potential for adverse environmental 
effects from emissions of lead. Note that modeling performed for this 
analysis is based on different inputs than SIP modeling done for the 
one remaining primary lead facility, and thus results differ.

  Table 4--Summary of Modeled Lead Concentrations Relative to the NAAQS Based on Estimated Actual 2008 and MACT
                                               Allowable Emissions
----------------------------------------------------------------------------------------------------------------
                                    Actual
                                     2008       Maximum impact--    Allowable      Maximum impact-- allowable
         Emission point            emissions    actual emissions    emissions              emissions
                                     (TPY)                          \1\ (TPY)
----------------------------------------------------------------------------------------------------------------
Main stack \2\..................       13.31  0.05 times the             65.8  0.25 times the NAAQS.
                                               NAAQS.
Refining stacks.................        2.74  3 times the NAAQS..          NA  NA.
Furnace area stack: (controlled         1.81  2 times the NAAQS..        8.94  10 times the NAAQS.
 blast and drossing fugitives).
Fugitive dust \3\...............        2.85  50 times the NAAQS.        2.85  50 times the NAAQS.
----------------------------------------------------------------------------------------------------------------
\1\ Allowable emissions for the main stack and furnace area emission points are based on 1 lb of Pb/ton
  production (MACT limit); Refinery emissions are included as fugitive emissions under MACT but are now vented
  to a stack because of SIP requirements; therefore, we were unable to calculate a ``MACT allowable'' emission
  level.
\2\ Main stack is the emission point for sinter machine, blast furnace and drossing operations.

[[Page 9430]]

 
\3\ Fugitive dust emissions are covered by work practices under current MACT and were calculated via emission
  factors assuming compliance with the MACT. The site of maximum ambient air lead concentration resulting from
  fugitive dust emissions occurs in close proximity to the southeast boundary of the facility (see Figure 3.1-1
  of the risk assessment document). Note that this maximum result and its location are based on modeling 2008
  emissions using 1998 site-specific meteorology, and that these may differ from inputs used for other types of
  modeling (e.g., SIP modeling.)

2. Facility-wide Risk Assessment Results
    Our screening analysis determined that the organic HAP emissions 
from facility represented negligible risk and were determined to be 
insignificant with regard to this risk analysis. As a result, all 
significant HAP emissions from the one facility in this category are 
reflected in the risk analyses presented above; therefore, facility-
wide risks are equivalent to those of the source category.
3. Model to Monitor Comparison
    In addition to the results presented above, we also compared 
maximum AERMOD estimates of ambient air lead concentrations with those 
measured at 4 monitors in close proximity to the Herculaneum Primary 
Lead Smelting Facility for calendar year 2008. More specifically, we 
compared maximum 3-month rolling average lead concentrations (for 
calendar year 2008) calculated from data reported at the Main Street, 
Circle Street, South Cross, and Church Street monitors to the maximum 
3-month rolling average lead concentrations at model receptor locations 
in close proximity to these monitoring sites. These monitor locations 
were chosen because they represented the closest offsite monitors to 
the Herculaneum primary lead smelter. Thus, lead measurements at these 
monitoring sites would likely be dominated by emissions from this 
facility which is important given that AERMOD estimates of ambient air 
lead concentrations only considered lead emissions from this facility 
(i.e., only lead emissions from the Herculaneum primary lead smelter 
were used as inputs into AERMOD).
    Results of this analysis are presented in Table 5 and indicate that 
with respect to the Main Street and Circle Street monitors, AERMOD 
underestimates 3-month maximum lead concentrations by approximately 
2.8- and 4.2-fold, respectively. While these monitor to model 
comparisons are not in complete agreement on a point-by-point basis, we 
note that this would not be expected given the general uncertainties 
associated with using dispersion modeling to estimate ambient pollutant 
concentrations and considering that the meteorological data used to 
develop the model estimates were from a different year than the actual 
monitoring and emissions data (i.e., meteorological data used in the 
AERMOD simulation was from 1998 while the emissions estimates and the 
monitoring data were from 2008). However, results do indicate that the 
maximum 3-month average lead concentration across the group of monitors 
nearest the facility is approximately equal to the maximum 3-month 
average lead concentration estimated by AERMOD across the group of 
these monitoring sites (i.e., both the Main Street monitor and the 
South Cross AERMOD estimate indicate the maximum 3-month average lead 
concentration to be approximately 2.1 [micro]g/m3). Taken together, 
these results indicate that AERMOD estimates of ambient air lead 
concentration provide a reasonable representation of the measured 3-
month maximum lead concentrations present in the ambient air near this 
facility.
---------------------------------------------------------------------------

    \20\ Maximum 3-month monitored concentrations were calculated 
for the year 2008 based on data submitted to EPA's Air Quality 
System (AQS).
    \21\ Negative sign denotes an underestimation of AERMOD modeled 
ambient lead concentrations, relative to monitored concentrations. 
AERMOD estimated concentrations were based on the 2008 emissions 
estimates described in section V.A.

 Table 5--Comparison of AERMOD Modeled to Ambient Air Lead Concentrations Reported by Four Monitors Surrounding
                                 the Herculaneum Primary Lead Smelting Facility
----------------------------------------------------------------------------------------------------------------
                                                          Maximum AEMOD     Maximum monitored 3-
                                                         modeled 3-month         month lead          Model to
                       Location                         lead concentration   concentration \20\   monitor ratio
                                                           ([mu]g/m\3\)         ([mu]g/m\3\)           \21\
----------------------------------------------------------------------------------------------------------------
Main Street..........................................                 0.47                 3.14             -4.6
Circle Street........................................                 0.38                 1.14             -3.0
South Cross..........................................                 2.13                 0.75              2.8
Church Street........................................                 1.99                 0.47              4.2
----------------------------------------------------------------------------------------------------------------

4. Demographic Risk Analysis Results
    Demographic analyses were performed to investigate the population 
distribution of: (1) Cancer risks at or above 1-in-1 million and (2) 
risks from ambient air lead concentrations above the NAAQS for lead. 
Results are summarized in Table 5 and are based on modeling using 
estimated actual emissions levels for the population living within 50 
km of this facility.

                        Table 6--Primary Lead Smelting Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                                                Population with
                                                                             Population with    ambient air lead
                                                             Nationwide        cancer risk       concentrations
                                                                            greater than 1 in    exceeding the
                                                                                a million            NAAQS
----------------------------------------------------------------------------------------------------------------
Total population.......................................      285,000,000              4,900              1,900
----------------------------------------------------------------------------------------------------------------
                                                 Race by percent
----------------------------------------------------------------------------------------------------------------
White..................................................               75                 96                 96

[[Page 9431]]

 
All Other Races........................................               25                  4                  4
----------------------------------------------------------------------------------------------------------------
                                                 Race by percent
----------------------------------------------------------------------------------------------------------------
White..................................................               75                 96                 96
African American.......................................               12                  4                  3
Native American........................................                0.9                0.2                0
Other and Multiracial..................................               12                  1                  0.8
----------------------------------------------------------------------------------------------------------------
                                              Ethnicity by percent
----------------------------------------------------------------------------------------------------------------
Hispanic...............................................               14                  1                  0.3
Non-Hispanic...........................................               86                 99                 99.7
----------------------------------------------------------------------------------------------------------------
                                                Income by percent
----------------------------------------------------------------------------------------------------------------
Below poverty level....................................               13                 15                 15
Above poverty level....................................               87                 85                 85
----------------------------------------------------------------------------------------------------------------

    Results of the risk assessment indicate that there are 
approximately 4,900 people exposed to a cancer risk greater than 1-in-1 
million, and 1,900 people in areas with ambient air lead concentrations 
above the NAAQS for lead. In both instances, the demographics analysis 
estimates that about 4 percent of these populations can be classified 
as a minority (listed as ``all Other Races'' in the table), which is 
well below the national percentage of 25. Similarly, in the cancer and 
lead demographic analyses, the percentage of ``African American,'' 
``Hispanic,'' ``Native American,'' and ``Other and Multiracial'' 
population groups are well below the corresponding national 
percentages. With respect to the percentage of those ``Below the 
Poverty Level,'' in both demographic analyses there is a small (2 
percent) increment above the corresponding national percentage. 
However, given that the total population affected is small (i.e., 4,900 
individuals for cancer risk greater than 1-in-1 million and 1,900 
individuals in areas with lead concentrations above the NAAQS), we do 
not think this indicates any significant potential for disparate 
impacts to the specific demographic groups analyzed.
    Moreover, given the extent to which lead may impact children's 
health, we further note that our demographic analysis doesn't indicate 
the presence of a higher percentage of children than one would normally 
expect around this facility. That is, while the national percentage of 
children 18 years and younger is 27%, the percentage of children living 
near this facility who are estimated to be exposed to lead 
concentrations above the NAAQS is only slightly higher at 28% (see Risk 
and Technology Review--Analysis of Socio-Economic Factors for 
Populations Living Near Primary Lead Smelting Facilities in the docket 
for this proposed rulemaking), a difference which is likely not 
significant.

C. What are our proposed decisions on risk acceptability and ample 
margin of safety?

1. Risk Acceptability
    As noted in section III.B of this preamble, we weigh all health 
risk factors in our risk acceptability determination, including cancer 
risks to the individual most exposed, risk estimation uncertainty, and 
other health information. For the Primary Lead Smelting source 
category, the risk analysis indicates that the cancer risks to the 
individual most exposed could be as high as 30-in-1 million due to 
actual or MACT-allowable emissions. These risks are considerably less 
than 100-in-1 million, which is the upper bound of the presumptive 
range of acceptability. The incidence of cancer is very low--0.0008 
excess cancer cases per year; or one case every 1,250 years. Similarly, 
the risks of chronic non-cancer health effects from HAP emissions other 
than lead were low, with a maximum HQ of 1. Moreover, while an initial 
screening analysis suggested that fugitive emissions of arsenic had the 
potential to create a risk of acute health effects, a refined analysis 
based on our knowledge of this emission source indicated that the risk 
was low (HQ = 0.6). In addition to these health analyses, a 
demographics analysis did not indicate the potential for significantly 
disproportionate heath impacts (see above, section V(3)(c)). Thus, 
risks associated with the non-lead emissions from the Primary Lead 
Smelting source category for cancer, acute and chronic non-cancer 
health effects and environmental effects are considered acceptable.
    However, since ambient air lead concentrations resulting from 
emissions from this facility were modeled to be in excess of the NAAQS 
for lead, the risks associated with lead emissions from this facility 
were judged to be significant. Our analysis estimated that modeled off-
site ambient air lead concentrations (based on actual 2008 emissions) 
resulting from this facility could be as high as 50 times the NAAQS for 
lead based on fugitive dust emissions, and that approximately 1,900 
individuals could be exposed to lead concentrations in excess of the 
NAAQS. Given that the NAAQS for lead was set to ``provide increased 
protection for children and other at-risk populations against an array 
of adverse health effects, most notably including neurological effects 
in children, including neurocognitive and neurobehavioral effects (73 
FR 67007)'', we are proposing that risks associated with lead emissions 
from this source category are unacceptable.
    As noted above, our risk analysis for lead was based on modeled 3-
month rolling average lead concentrations in ambient air in comparison 
to the primary lead NAAQS. We believe that in order to provide an 
acceptable level of risk, lead concentrations in the ambient air must 
be reduced to the level of the lead NAAQS. Thus, we

[[Page 9432]]

considered specific emission limits for the three emission sources/
points that were modeled to result in lead concentrations in excess of 
the NAAQS (see Table 4); refinery stack, furnace area stack, and 
fugitive dust emissions, with the majority of fugitive dust impacts 
from material handling sources. Based on our analysis, we conclude that 
in order to meet the NAAQS for lead at all model receptors, fugitive 
dust emissions would have to be reduced by approximately 98 percent to 
0.064 TPY, refinery stack emissions and furnace area stack emissions 
would have to be reduced by approximately 80 percent to a total of 0.91 
TPY (the maximum impacts of refinery and furnace emission points occur 
at the same location.) Further, because the maximum ambient air impacts 
of the refinery/furnace emissions, the fugitive dust emissions, and the 
main stack do not significantly overlap each other, we estimate that 
lead emissions from all emission points other than the main stack would 
have to be limited to a total of approximately 0.97 TPY in order to 
ensure 3-month rolling average ambient air lead concentrations do not 
exceed the lead NAAQS level of 0.15 [mu]g/m\3\. As noted above, 
emissions from the main stack (i.e., emission point for sinter machine, 
blast furnace and drossing operations) did not result in ambient air 
lead concentrations in excess of the lead NAAQS at modeled locations 
within 50 km of the property boundary and thus we are not proposing any 
reductions at the main stack in order to ensure an acceptable level or 
risk.
    Once we determined the emissions reductions necessary to achieve an 
acceptable level of risk, we investigated available emissions control 
options and their ability to reduce emissions and health risks for 
fugitive dust and for stack emissions from both the refining and 
furnace area stacks. Control options considered for reducing fugitive 
dust emissions and associated risks include improved or additional work 
practices, site remediation, application of additional capture/control 
measures, and lead production limitations. With the exception of site 
remediation, all of these control measures have been implemented to 
varying degrees at the Doe Run facility in response to the Missouri 
SIP, as revised in 2002 and the 2007 revisions submitted for approval 
to the SIP. As such, because the actual emissions for 2008 reflect the 
implementation of those control measures, requiring those controls 
under the MACT would be unlikely to yield the additional 98 percent 
reduction in fugitive emissions necessary to meet the primary lead 
NAAQS level of 0.15 [micro]g/m \3\. Thus, our evaluation of risks based 
on actual emissions already considered emissions with these controls 
largely in place. In order to ensure that site remediation efforts, or 
any other efforts the source may choose to undertake, will result in 
sufficient emission reductions to address the unacceptable level of 
risk, we are proposing to establish a lead concentration in air limit 
of 0.15 [micro]g/m \3\ to be measured at locations approved by the 
Administrator. This lead concentration in air limit would be 
established as the enforceable requirement to address fugitive 
emissions under the MACT standard.\22\ Because we are proposing a 
concentration limit to address fugitive dust emissions, we no longer 
believe it is necessary for the affected facility to provide a plan to 
the Administrator describing work practices that will be used to reduce 
fugitive emissions. Therefore, we are proposing to remove the 
requirement to develop and submit a work practice standard operating 
procedure (SOP) manual as required in Sec.  63.1544(a).
---------------------------------------------------------------------------

    \22\ Under the consent decree, of which we sought public comment 
last fall, fugitive dust sources will be addressed by site 
remediation; however, some fugitive dust emissions will remain 
during the remediation of the site, which will likely extend beyond 
April 2014.
---------------------------------------------------------------------------

    As an alternative to proposing compliance monitoring requirements 
for demonstration of compliance with the lead concentration in air 
limit, we considered retaining the current fugitive dust emissions 
requirement to develop and submit to the Administrator or delegated 
authority a work practices SOP. Using this alternative approach, we 
believe it would be necessary to modify the current general 
requirements for an SOP by specifying the minimum work practice 
requirements that the plan must include. For example, under this 
alternative approach, we would require that the SOP must include, at a 
minimum, detailed descriptions of all measures that would be used to 
control fugitive dust emissions from plant roadways; material storage, 
transfer and handling areas; sinter machine areas; furnace areas; 
refining and casting areas; and other areas the Administrator may 
identify. Further, EPA would require that the SOP contain detailed 
descriptions of work practices including road watering and automatic 
sprinklers, methods to remove dust from paved surfaces to reduce 
emissions from traffic, maintenance of minimum water content for ore 
concentrate and for baghouse dust that will be handled or transferred, 
and procedures for the inspection of building siding or damages and 
openings. The SOP would be required to include procedures, including 
recordkeeping, to ensure that the work practices are being implemented 
at a frequency and in a manner that would ensure that fugitive dust 
emissions are being minimized. To determine whether the work practices 
described in the SOP are reducing emissions sufficient to comply with 
the lead concentration in air limit, the owner or operator would be 
required once a year to model the fugitive dust emissions using 
measurement data or emission factors according to an approved fugitive 
dust emissions modeling plan. At a minimum, EPA would require that this 
modeling plan include a detailed description of each fugitive dust 
emission source; a detailed description of the control practices or 
techniques used to limit fugitive dust emissions from each source; the 
emission factors, test data or other methods used to characterize and 
quantify lead emissions from each source; a description of the 
emissions modeling that will be used to estimate the concentrations of 
lead in air at or near the property boundary as contributed by each 
source as well as cumulatively contributed by all sources; a 
description of process or other conditions that would indicate the need 
to demonstrate compliance more often than annually; the calculations to 
be used to show compliance with the air lead concentration limit that 
consider the highest modeled air lead concentrations from the modeled 
fugitive dust sources and any contributions from background lead 
concentrations in air; and a description of the records that will be 
kept. We are seeking comments on the proposed requirements to monitor 
air lead concentrations versus the alternative approach described 
above, of requiring extensive work practices and a work practice SOP in 
conjunction with emissions modeling, to demonstrate compliance with the 
air lead concentration limit.
    Measures available for reducing lead emissions from the refining 
and furnace area stacks include upgrading existing baghouses by 
replacing the existing fabric bags with high efficiency membrane bag 
filters. Another option would be to add extra in-line baghouses after 
existing baghouses. Such measures would reduce lead emissions and 
associated risk to within acceptable levels.
    In summary, our analysis indicates that in order to ensure that 
lead emissions from this source do not pose an unacceptable risk, 
emissions from

[[Page 9433]]

this facility would need to be reduced to a level that would ensure 
that these emissions would not result in air lead levels greater than 
the 0.15 [micro]g/m \3\ for any 3-month period at all of the modeled 
locations. Further, we conclude that in order to achieve the 0.15 
[micro]g/m \3\ level (for any 3-month rolling average) at all modeled 
locations, fugitive dust emissions would need to be reduced by 98 
percent and the emissions from the furnace area and refining operation 
stacks would need to be reduced by 80 percent. We have identified 
emission reduction and control options for achieving the required 
reductions, which include implementation of site remediation, work 
practices, and upgrade of existing baghouses with membrane bags and/or 
addition of an additional in-series baghouse.
    We are proposing the following requirements to ensure that risk is 
reduced to an acceptable level.
     A stack lead emission cap of 0.91 TPY that would apply to 
the furnace area stack and the refining operation stacks.
     An air lead concentration limit of 0.15 [micro]g/m\3\ 
based on 3-month rolling average (to be measured at locations approved 
by the Administrator) to ensure that fugitive dust emission levels will 
not exceed the NAAQS.
    The proposed limits apply to both new and existing facilities. Any 
facility subject to the MACT would be required to meet these 
requirements for each emission unit it is operating that is subject to 
the limit. In order to address any fugitive dust emissions, the 
facility, regardless of whether it is operating all or just some of the 
emission sources covered by this action, would be required to meet the 
air lead concentration emission limit.
    For both new and existing facilities, compliance with the air lead 
concentration limit would be demonstrated using lead compliance 
monitoring devices and would be based on a rolling 3-month average 
concentration. The proposed rule requires development of a monitoring 
plan for approval by the Administrator that includes the minimum 
sampling and analysis methods and compliance demonstration criteria 
provided in the rule. A provision is included in this proposed rule 
that allows for reduced monitoring if the facility demonstrates an air 
lead concentration for three consecutive years at less than 50 percent 
of the air lead concentration limit. The monitoring can be reduced to 
once every six months unless one of the 6-month monitoring events 
exceeds 50 percent of the air lead concentration limit, at which time 
monitoring will be required to resume based on the initial plan 
approved by the Administrator until another three years of consecutive 
monitoring below 50 percent of the air lead concentration limit is 
achieved. The compliance requirements discussed above were designed to 
allow for flexibility, prevention of redundant requirements, and also 
to provide consistency with current monitoring required at the site. We 
are soliciting comment on this approach. For existing facilities, 
compliance with the emission limit for the furnace area and refinery 
stacks would be demonstrated through stack testing conducted on a 
quarterly basis. All performance testing will be consistent with the 
existing MACT testing requirements, with the exception of frequency. As 
provided in Sec.  63.153(e) of the current rule, the facility can 
reduce compliance testing frequency if the most recent three compliance 
tests demonstrated compliance. We are maintaining this provision, 
however, because this proposed rule increases the testing frequency to 
quarterly, the number of most recent tests necessary to comply with 
this provision will be increased from three to 12. New primary lead 
processing facilities would be required to demonstrate compliance using 
a lead continuous emission monitoring systems (CEMS). However, since 
the Agency has not finalized the performance specification for the use 
of these instruments, we are deferring the effective date of the 
requirement to install, correlate, maintain and operate lead CEMS until 
these actions can be completed. The lead CEMS installation deadline 
will be established through future rulemaking, along with other 
pertinent requirements. In the event operations commence at a new 
facility prior to promulgation of the performance specification, 
compliance would be demonstrated through quarterly stack testing until 
promulgation of the lead CEMS performance specification.
2. Ample Margin of Safety
    Reducing lead emissions to meet the NAAQS would ensure that 
emissions of all HAP do not pose an unacceptable risk. Once we ensure 
that the risk is acceptable, we then look to determine whether further 
reductions are appropriate to ensure an ample margin of safety. In this 
part of our analysis, we again consider the health factors we 
considered to determine whether the risks are acceptable but we also 
consider the cost of controls.
    With regard to lead emissions, we are proposing to require most of 
the emission sources at the facility to implement all technically 
feasible controls in order to ensure that the ambient air meets the 
level of the lead NAAQS, which is the level that we have determined 
will ensure an acceptable level of risk. Because all feasible controls 
will need to be adopted in order to meet that proposed standard, there 
are no additional controls to consider for the three emission sources: 
Fugitive dust emissions, the furnace area stack, and the refinery 
stacks. We further note that the same controls we have proposed for the 
three emission points to reduce lead emissions are the same controls 
that would reduce risks from cadmium and all other metal HAP known to 
be emitted from this source category. Thus, we are proposing that the 
controls required to ensure that risk from lead emissions from those 
three emission points is acceptable also protect public health with an 
ample margin of safety with regard to emissions from all metal HAP from 
these three emission points. Notably, after these standards are in 
place, we estimate that the MIR cancer risk due to the non-lead HAP 
will be less than 1-in-1 million.
    Our risk analysis indicates that the main stack emissions do not 
result in ambient air lead levels exceeding the NAAQS based on either 
actual or allowable emission levels. We determined, as discussed 
section V.D. below, that it is technologically feasible to reduce 
emissions from the main stack to a level well below the allowable level 
of the MACT, since those levels are currently being achieved, and thus 
we are proposing to require such controls under CAA section 112(d)(6). 
We evaluated whether there were additional controls to further reduce 
emissions from the main stack and determined that lead emissions from 
the main stack could be further reduced by replacing the standard cloth 
bags with membrane bags at a capital cost of approximately $2 million 
and an annual cost of $0.3 million. Assuming a 50 percent reduction 
from 2008 main stack emissions, the cost of reducing lead emissions 
would be about $40,000 to $229,000 per ton of lead. (See the Technical 
Support Document included in the docket for a complete discussion of 
this analysis.) Because the highest ambient air lead concentration 
resulting from the emissions from the main stack already is more than 
20 times below the level that is considered acceptable, it was 
determined that although additional controls such as membrane bags 
could result in additional emission reductions, the additional controls 
are not warranted since they would not

[[Page 9434]]

appreciably reduce risk. We are proposing that the MACT standard, with 
the changes we are proposing under the section 112(d)(6) technology 
review as described in section V.D. below will provide an ample margin 
of safety with regard to emissions of lead and other HAP from the main 
stack.

D. What are the results and proposed decisions from the technology 
review?

    We evaluated developments in practices, processes, and control 
technologies applicable to emission sources subject to the Primary Lead 
Smelting MACT. This included a search of the RBLC Clearinghouse, the 
California BACT Clearinghouse, the internet, and correspondence with 
state agencies and industry. We have determined that there have been 
advances in emission control measures since the Primary Lead Smelting 
MACT standard was originally promulgated in 1999.
    The 1999 MACT limit was set using the lead emission limits from the 
lead SIPs for the three states in which primary lead smelting sources 
were operational at the time of the rulemaking. EPA took each of the 
three lead SIP limits, in lb/day, divided them by the corresponding 
lead production capacity, in tons/day, and calculated a lead emission 
rate in lb/ton. The results were as follows:

ASARCO--Missouri 1.0 lb/ton
ASARCO--Montana 1.0 lb/ton
Doe Run--Missouri 0.84 lb/ton

    The values were ranked and the median value (1.0 lb/ton) was 
selected as representative of the MACT floor.
    Since the MACT standard was promulgated, the industry has undergone 
significant changes. Two of the three facilities have shut down. The 
only remaining primary lead smelting facility is the Doe Run smelter at 
Herculaneum, Missouri, which is subject to control requirements under 
the Missouri SIP for lead. The existing SIP, as well as a 2007 SIP 
revision submitted by the State and proposed for approval by EPA 
require numerous emissions-reducing measures and improvements to add-on 
control devices, processes, and work practices. We considered these 
developments in practices, processes, and control technologies in our 
technology review.
    Recent emissions tests (2000 through 2008) at the Doe Run facility 
support that these improvements have resulted in significantly lower 
emissions and demonstrate that actual lead emissions from the facility 
are much lower than are allowed under the current MACT rule. To assess 
the impacts of developments in practices, processes and control 
technologies on lead emissions, emissions data from 2008 were compared 
with emissions data from 2000. Data from 2008 were selected because 
they reflect the many improvements that have been implemented at the 
facility since promulgation of the MACT rule. Emissions data from 
earlier years would not reflect all of the emission-reducing changes 
that have been implemented at the Doe Run facility given that some of 
the improvements were not implemented until 2007 and 2008. As described 
above, technological improvements to baghouses and processes that have 
been implemented at the facility since the MACT rule was promulgated 
have resulted in substantially lower emissions from these sources at 
this facility. These improvements include upgrade of cloth bags and 
ventilation improvements. In 2008, lead emissions from the main stack, 
which vents emissions from the sintering operation and the blast and 
dross furnace, were 13.31 TPY. In addition, emissions from the furnace 
area stack (i.e., the blast furnace and dross plant building which vent 
to baghouse 7) were 1.81 TPY, for a total of approximately 15.1 TPY. At 
the 2008 lead production rate of 149,500 tons, the lead emission rate 
for these sources at Doe Run was about 0.2 lb/ton, or 80 percent less 
than the current MACT limit of 1 lb/ton. Based on this demonstrated 
performance, EPA believes that under Section 112(d)(6), the MACT 
standard should be revised to reflect the reduction achieved in 
practice.
    Because we believe that the 2008 emissions of 13.31 TPY from the 
main stack (or combined sintering/blast furnace/drossing operations) 
reflect the annual rate of emissions achievable as a result of the 
technological improvements that have been made since 1999, we are 
proposing an emission limit based on the actual 2008 annual emissions 
that vent to the main stack (i.e., sintering, blast furnace and 
drossing operations). In order to account for variability in the 
operation and emissions, recent stack tests were used to calculate the 
95 percent upper predictive limit (UPL). The 95 percent UPL for the 
main stack is 15 TPY. Variability in the operations and emission for 
this source are discussed in more detail in Section E below.
    Although we believe that there have been developments in processes, 
practices and control technologies with regard to the furnace area 
stack and with regard to refining and casting operations, as reflected 
by the more stringent requirements that have been implemented in 
accordance with the approved SIP and the 2007 SIP revisions; we are not 
proposing additional requirements for these stacks as part of our 
technology review because we have already proposed that these stacks 
implement all feasible controls, regardless of cost, in order to ensure 
that the risks due to these emission points are acceptable. Thus, there 
are no additional developments in practices, processes and control 
technologies beyond those which are reflected in the emission limits we 
have proposed to meet CAA section 112(f)(2), above.
    To be consistent with the existing MACT standard, EPA is proposing 
to retain the plant-wide pound per ton of production format that 
currently applies to the aggregate emissions from the main stack and 
the furnace area stack. Because there are also stacks for the refining 
and casting operations, we are proposing to include those emissions as 
part of the plant-wide emission limit. Thus we are proposing a plant-
wide lead emission limit of 0.22 pounds of lead per ton of lead 
produced based on the proposed reductions due to the section 112 (f)(2) 
risk review for the furnace area and refining operations stacks 
(discussed above in Section C) and the reduction in emissions from the 
main stack (sinter/blast furnace/drossing operations) based on this 
Section 112(d)(6) technology review This proposed plant-wide lead 
emission limit was determined by summing the 15 TPY for the main stack 
and the 0.91 TPY for the furnace area and the refining operation, and 
dividing by the annual production from 2008 of 149,564 tons. We note 
that variability was only applied in establishing technology-based 
emissions from the main stack in order to establish a plant-wide 
emission limit. Because the emission levels required from the refining 
operation and furnace area stacks are based on acceptable risk, we 
conclude it is not appropriate to consider variability in establishing 
limits for these emission points.
    We are proposing that the plant-wide lead emission limit apply to 
new and existing facilities that are subject to the MACT. By default 
this would include any new, controlled lead processing source not 
currently covered, including lead processing by other than the current 
techniques. We are requesting comment on the appropriateness of 
applying the plant-wide lead emission limit to any future new lead 
processing technique.
    For the existing facility, compliance with the plant-wide stack 
emission limit would be demonstrated in the same

[[Page 9435]]

manner as discussed above in section V.C.1 for the furnace area and 
refining stack limit (i.e., stack testing on a quarterly basis). We are 
proposing stack testing on a quarterly basis as opposed to testing on 
an annual basis since this allows the facility the opportunity to 
adjust their emissions throughout the year to be in compliance, rather 
than to find they are out of compliance at the end of the year, thereby 
risking violations. This schedule also coincides with other quarterly 
monitoring and reporting required of the facility. Also as discussed in 
section V.C.1, new primary lead processing facilities would be required 
to demonstrate compliance using lead continuous emission monitoring 
systems (CEMS).

E. Variability

    In assessing sources' performance, EPA may consider variability 
both in identifying which performers are ``best'' and in assessing 
their level of performance. Brick MACT, 479 F. 3d at 881-82; see also 
Mossville Envt'l Action Now v. EPA, 370 F.3d 1232, 1241-42 (D.C. Cir 
2004) (EPA must exercise its judgment, based on an evaluation of the 
relevant factors and available data, to determine the level of 
emissions control that has been achieved by the best performing sources 
considering these sources' operating variability).
    Variability in lead producers' performance has a number of causes. 
For emissions of lead compounds that are controlled by baghouses, the 
variability is chiefly due to variations in performance of the control 
device for which both run-to-run and test-to-test variability must be 
accounted.\23\
---------------------------------------------------------------------------

    \23\ Run-to-run variability is essentially within-test 
variability, and encompasses variability in individual runs 
comprising the compliance test, and includes uncertainties in 
correlation of monitoring parameters and emissions, and imprecision 
of stack test methods and laboratory analysis. 72 FR 54877 (Sept. 
27, 2007). Test-to-test variability results from variability in 
pollution device control efficiencies over time (depending on many 
factors, including for fabric filters the point in the maintenance 
cycle in which a fabric filter is tested). Test-to-test variability 
can be termed long-term variability. 72 FR 54878.
---------------------------------------------------------------------------

    In determining the contribution to a plant-wide emission limit of 
the main stack, we considered annual emissions discharged from the air 
pollution control devices that control lead emissions. For this rule, 
we used the 2008 emissions reported by Doe Run to the State of 
Missouri.
    We assessed variability using a statistical formula designed to 
estimate an emissions level that is equivalent to the source's 
performance based on future compliance tests. Specifically, the 
calculated limit is an upper prediction limit (UPL) calculated with the 
Student's t-test using the TINV function in Microsoft Excel[supreg]. 
The Student's t-test has also been used in other EPA rulemakings (e.g., 
NESHAP for Portland Cement Manufacturing [75 FR 54970, September 9, 
2010]; NSPS for Hospital/Medical/Infectious Waste Incinerators [74 FR 
51368, October 6, 2009]; NESHAP for Industrial, Commercial, and 
Institutional Boilers and Process Heaters-Proposed [75 FR 32006, June 
4, 2010]) in accounting for variability. A prediction interval for a 
future observation is an interval that will, with a specified degree of 
confidence, contain the next (or some other pre-specified) randomly 
selected observation from a population. In other words, the prediction 
interval estimates what the upper bound of future values will be, based 
upon present or past samples taken. The UPL consequently represents the 
value which we can expect the mean of future observations (3-run 
average for lead) to fall below within a specified level of confidence, 
based upon the results of an independent sample from the same 
population. In other words, if we were to randomly select a future test 
condition from any of these sources (i.e., average of 3 runs or 30-day 
average) we can be 95 percent confident that the reported level will 
fall at or below the UPL value. Use of the UPL is appropriate in this 
rulemaking because it sets a limit any single or future source can meet 
based on the sources past performance.
    This formula uses a pooled variance (in the s\2\ term) that 
encompasses all the data-point to data-point variability. Where 
variability was calculated using the UPL statistical approach, we used 
the sample standard deviation calculated from the emissions data 
distributions for lead. The standard deviation is the common measure of 
the dispersion of the data set around an average. We note here that the 
methodology accounts for both short-term and long-term variability and 
encompasses run-to-run and test-to-test variability.
    We adopted a form of the UPL equation that has been used in more 
recent rulemakings. See 75 FR 54970 (September 9, 2010), 75 FR 32020 
(June 4, 2010) and 75 FR 31905 (June 4, 2010). The UPL used in this 
proposed rule is calculated by:

[GRAPHIC] [TIFF OMITTED] TP17FE11.000


Where:

x = 2008 annual emissions
n = the number of test runs
m = the number of test runs in the compliance average
s\2\ = observed variance
t = student t distribution statistic

This calculation was performed using the following Excel functions: 95 
percent UPL = 2008 annual emissions + [STDEV (Test Runs) x TINV (2 x 
probability, n-1 degrees of freedom) x SQRT ((1/n) + (1/m))], for a 
one-tailed t-value, probability of 0.05, and sample size of n.

F. What other actions are we proposing?

    As discussed in Section III.C. above, EPA is proposing to remove 
provisions in the existing standard that would have exempted sources 
from complying with the standard during periods of startup, shutdown 
and malfunction. Specifically we are proposing revisions to subpart TTT 
Table 1 and rule provisions to remove applicability of the General 
Provisions with regard to SSM and remove the exemption for bag leak 
detection alarm time attributable to SSM events from determining 
compliance with the total alarm time limit. In addition, we are 
proposing to promulgate an affirmative defense to civil penalties for 
exceedances of emission limits caused by malfunctions, as well as 
criteria for establishing the affirmative defense.
    EPA has attempted to ensure that we have not included in the 
proposed regulatory language any provisions that are inappropriate, 
unnecessary, or redundant in the absence of the SSM exemption. We are 
specifically seeking comment on whether there are any such provisions 
that we have inadvertently incorporated or overlooked.

[[Page 9436]]

VI. Proposed Action

A. What actions are we proposing as a result of the residual risk 
reviews?

    Consistent with CAA section 112 (f)(2), we are proposing to amend 
the MACT standard for primary lead processing to include a lead 
concentration in air limit of 0.15 [micro]g/m3 (based on 3-month 
rolling averages)to be measured at locations approved by the 
Administrator to address the risks from all fugitive dust emissions 
addressed in 40 CFR 63.1544. We are also proposing to remove refining 
and casting operations from Sec.  63.1544 and to require that emissions 
from these operations be vented to one or more stacks. Finally, we are 
proposing to establish an emission cap of 0.91 TPY for the furnace area 
stack and the refining operation stacks. These limits were established 
based on the level of reductions in lead emissions from the three 
sources that are necessary to show that the lead NAAQS will not be 
exceeded within the 50 km modeled domain. We believe the NAAQS level 
represents an acceptable level of risk and that the proposed limits are 
necessary to ensure that risks from these sources are acceptable. We 
are proposing that the risk posed by lead emissions from the main stack 
and by emissions of all other HAP is acceptable.
    We are proposing that compliance with the emission limits 
applicable to the furnace area and refinery stacks would be 
demonstrated based on stack testing for existing facilities and, for 
new facilities, using CEMS after promulgation of performance 
specifications for a CEMS capable of measuring lead emissions.
    We are proposing that compliance with the lead concentration in air 
limit would be demonstrated using a compliance monitoring system 
approved by the Administrator.
    We are also proposing that the Primary Lead Smelting standard, as 
we have proposed to revise it to ensure an acceptable level of risk, 
will also protect public health with an ample margin of safety. With 
regard to lead emissions from fugitive dust sources and from the 
furnace and refining area stacks, we have not identified any feasible 
controls beyond those needed to meet the proposed emission limits that 
will provide an acceptable level of risk . The standards we are 
proposing to ensure an acceptable level of risk for lead emissions will 
also reduce the risk from cadmium and will also reduce emissions of all 
other metal HAP known to be emitted from this source category because 
the controls that will reduce lead emissions are the same controls that 
will reduce emissions of these other metal HAP. The cancer risk from 
cadmium emissions will be reduced from 30-in-1 million to less than 1-
in-1 million. Therefore, we are proposing that the existing MACT, as it 
would be modified based on our proposed requirements for lead 
emissions, would provide an ample margin of safety with respect to 
emissions from all metal HAP.
    With regard to lead emissions from the main stack, we have 
identified developments in practices, processes and control 
technologies since promulgation of the MACT standard in 1999, and are 
proposing a reduced emission limit for the main stack based on these 
improvements. Since the main stack does not pose an unacceptable risk 
at its current emissions level, we are not proposing reductions for 
this emission point under 112(f)(2). However, we are proposing a 
reduced emission limit under 112(d)(6) due to the improvements we 
identified.

B. What actions are we proposing as a result of the technology reviews?

    For the Primary Lead Smelting source category, we have determined 
that there have been developments in practices, processes, or control 
technologies since the promulgation of the MACT standards that are 
feasible for the one facility in this source category to implement at 
the main stack. The proposed limit is consistent with the current 
demonstrated performance of the facility based on obligations adopted 
by the State and reflected in the 2002 SIP and 2007 SIP revision for 
Doe Run.
    We are proposing that a performance of 15.11 TPY has been 
demonstrated for emissions from the main stack, taking into 
consideration variability of emissions from that stack. The existing 
MACT lead emissions standard that is applicable to emissions from the 
main stack is a plant-wide emission limit that also applies to 
emissions from the furnace-area stack. We are proposing to revise the 
plant-wide limit to reflect the 15.11 TPY limit for the main stack as 
well as the emissions limits we are proposing for the furnace-area and 
refinery stacks under CAA section 112(f)(2). Thus, we are proposing to 
revise the plant-wide emissions limit from 1 pound of lead per ton of 
lead produced, to 0.22 pound of lead per ton of lead produced and the 
new limit would include emissions from the refinery stack as well as 
emissions from the main stack and the furnace area stack. Compliance 
with this limit would be demonstrated quarterly with stack testing. For 
new facilities, compliance would be demonstrated using lead CEMS.

C. What other actions are we proposing?

    As described above, we are proposing to amend the applicability 
section for the MACT rule to tailor it to the definition of the source 
category we established under CAA section 112(c)(1). See 
``Documentation for Development of Initial Source Category List--Final 
Report'', USEPA/OAQPS, EPA-450/3-91-030, July, 1992. In support of this 
applicability provision clarification, we are also proposing to replace 
the definition of ``primary lead smelter'' with a definition of 
``primary lead processor''. The ``primary lead processor'' definition 
would include any facility that produces lead from processing of lead 
sulfide ore by pyrometallurgical (smelting) or any other technique. We 
are also proposing to add definitions of ``secondary lead smelters'', 
``lead refiners'', and ``lead remelters'' to clarify the meaning of 
those terms in the second sentence of the applicability provision.
    We propose to amend the Primary Lead Smelting MACT standards to 
remove the language that exempts bag leak detection system alarm time 
incurred during periods of SSM from inclusion in the allowable alarm 
time. This change is being made to ensure the rule is consistent with 
the court's ruling in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 
2008). We are also proposing minor modifications throughout the rule to 
incorporate plain language and to make editorial and clarifying 
revisions. In addition, we are proposing changes to Table 1 of the rule 
to reflect revisions to SSM requirements.

D. Compliance Dates

    We are proposing that the requirements under CAA section 112(f)(2) 
for the one existing source, if finalized, must be implemented no later 
than two years after the effective date of this rule. Consistent with 
CAA section 112(f)(4)(B), we are proposing that a two-year compliance 
period is necessary so the facility has adequate time to install 
additional controls and demonstrate compliance, including the time 
necessary to purchase, install and test replacement bags, or if the 
facility decides to add a new baghouse in series with an existing 
baghouse, seek bids, select a vendor, install and test the new 
equipment; prepare and submit the required monitoring plan to monitor 
lead concentrations in air; purchase, install and conduct quality 
assurance and quality control measures on compliance monitoring 
equipment and; conduct site remediation necessary to

[[Page 9437]]

reduce fugitive emissions. A two-year compliance period is also 
consistent with the schedule of required actions contained in the 
Consent Decree.
    In addition, we are proposing that the plant-wide limit that would 
reflect reductions required for the main stack pursuant to CAA section 
112(d)(6) and for the furnace area and refinery stacks pursuant to CAA 
section 112(f)(2) must be met no later than two years after the 
effective date of this rule. Because these limits reflect the 
reductions from the furnace area and refinery stacks required under 
section 112(f)(2), we believe a two-year compliance timeframe is needed 
for the same reasons provided above.

VII. Request for Comments

    We are soliciting comments on all aspects of this proposed action. 
All comments received during the comment period will be considered. In 
addition to general comments on this proposed actions, we are also 
interested in any additional data that may help to reduce the 
uncertainties inherent in the risk assessments. We are specifically 
interested in receiving corrections to the dataset used for risk 
modeling. Such data should include supporting documentation in 
sufficient detail to allow characterization of the quality and 
representativeness of the data or information. Please see the following 
section for more information on submitting data.

VIII. Submitting Data Corrections

    The facility-specific data used in the source category risk 
analyses and demographic analyses are available for download on the RTR 
Web Page at http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files 
include detailed information for each HAP emissions release point for 
the facility included in the source category.
    If you believe the data are not representative or are inaccurate, 
please identify the data in question, provide your reason for concern, 
and provide any ``improved'' data that you have, if available. When you 
submit data, we request that you provide documentation of the basis for 
the revised values to support your suggested changes. To submit 
comments on the data downloaded from the RTR Web page, complete the 
following steps:
    (1) Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information. The data fields that may 
be revised include the following:

------------------------------------------------------------------------
          Data element                          Definition
------------------------------------------------------------------------
Control Measure.................  Are control measures in place? (yes or
                                   no).
Control Measure Comment.........  Select control measure from list
                                   provided, and briefly describe the
                                   control measure.
Delete..........................  Indicate here if the facility or
                                   record should be deleted.
Delete Comment..................  Describes the reason for deletion.
Emission Calculation Method Code  Code description of the method used to
 For Revised Emissions.            derive emissions. For example, CEM,
                                   material balance, stack test, etc.
Emission Process Group..........  Enter the general type of emission
                                   process associated with the specified
                                   emission point.
Fugitive Angle..................  Enter release angle (clockwise from
                                   true North); orientation of the y-
                                   dimension relative to true North,
                                   measured positive for clockwise
                                   starting at 0 degrees (maximum 89
                                   degrees).
Fugitive Length.................  Enter dimension of the source in the
                                   east-west (x-) direction, commonly
                                   referred to as length (ft).
Fugitive Width..................  Enter dimension of the source in the
                                   north-south (y-) direction, commonly
                                   referred to as width (ft).
Malfunction Emissions...........  Enter total annual emissions due to
                                   malfunctions (TPY).
Malfunction Emissions Max Hourly  Enter maximum hourly malfunction
                                   emissions here (lb/hr).
North American Datum............  Enter datum for latitude/longitude
                                   coordinates (NAD27 or NAD83); if left
                                   blank, NAD83 is assumed.
Process Comment.................  Enter general comments about process
                                   sources of emissions.
REVISED Address.................  Enter revised physical street address
                                   for MACT facility here.
REVISED City....................  Enter revised city name here.
REVISED County Name.............  Enter revised county name here.
REVISED Emission Release Point    Enter revised Emission Release Point
 Type.                             Type here.
REVISED End Date................  Enter revised End Date here.
REVISED Exit Gas Flow Rate......  Enter revised Exit Gas Flowrate here
                                   (ft\3\/sec).
REVISED Exit Gas Temperature....  Enter revised Exit Gas Temperature
                                   here (F).
REVISED Exit Gas Velocity.......  Enter revised Exit Gas Velocity here
                                   (ft/sec).
REVISED Facility Category Code..  Enter revised Facility Category Code
                                   here, which indicates whether
                                   facility is a major or area source.
REVISED Facility Name...........  Enter revised Facility Name here.
REVISED Facility Registry         Enter revised Facility Registry
 Identifier.                       Identifier here, which is an ID
                                   assigned by the EPA Facility Registry
                                   System.
REVISED HAP Emissions             Enter revised HAP Emissions
 Performance Level Code.           Performance Level here.
REVISED Latitude................  Enter revised Latitude here (decimal
                                   degrees).
REVISED Longitude...............  Enter revised Longitude here (decimal
                                   degrees).
REVISED MACT Code...............  Enter revised MACT Code here.
REVISED Pollutant Code..........  Enter revised Pollutant Code here.
REVISED Routine Emissions.......  Enter revised routine emissions value
                                   here (TPY).
REVISED SCC Code................  Enter revised SCC Code here.
REVISED Stack Diameter..........  Enter revised Stack Diameter here
                                   (ft).
REVISED Stack Height............  Enter revised Stack Height here (Ft).
REVISED Start Date..............  Enter revised Start Date here.
REVISED State...................  Enter revised State here.
REVISED Tribal Code.............  Enter revised Tribal Code here.
REVISED Zip Code................  Enter revised Zip Code here.
Shutdown Emissions..............  Enter total annual emissions due to
                                   shutdown events (TPY).
Shutdown Emissions Max Hourly...  Enter maximum hourly shutdown
                                   emissions here (lb/hr).

[[Page 9438]]

 
Stack Comment...................  Enter general comments about emission
                                   release points.
Startup Emissions...............  Enter total annual emissions due to
                                   startup events (TPY).
Startup Emissions Max Hourly....  Enter maximum hourly startup emissions
                                   here (lb/hr).
Year Closed.....................  Enter date facility stopped
                                   operations.
------------------------------------------------------------------------

    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter e-
mail address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations, etc.).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID Number EPA-HQ-OAR-2004-0305 (through one of the methods 
described in the ADDRESSES section of this preamble). To expedite 
review of the revisions, it would also be helpful if you submitted a 
copy of your revisions to the EPA directly at [email protected] in addition 
to submitting them to the docket.
    5. If you are providing comments on a facility, you need only 
submit one file for that facility, which should contain all suggested 
changes for all sources at that facility. We request that all data 
revision comments be submitted in the form of updated Microsoft[supreg] 
Access files, which are provided on the http://www.epa.gov/ttn/atw/rrisk/rtrpg.html Web page.

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a significant regulatory action because it raises novel legal 
and policy issues. Accordingly, EPA submitted this action to the Office 
of Management and Budget (OMB) for review under Executive Order 12866 
and any changes made in response to OMB recommendations have been 
documented in the docket for this action.

B. Paperwork Reduction Act

    The information collection requirements in this rule have been 
submitted for approval to the Office of Management and Budget (OMB) 
under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The 
Information Collection Request (ICR) document prepared by EPA has been 
assigned EPA ICR number 1856.07.
    We are proposing new paperwork requirements to the Primary Lead 
Smelting source category in the form of monitoring for lead 
concentrations in air and increased frequency for stack testing as 
described in 40 CFR 63.1547(k) (compliance monitoring) and 40 CFR 
63.1546 (stack testing). These requirements are described in section 
VI.A and B. Although these are additional requirements under today's 
proposed rule, they are consistent with existing monitoring and testing 
currently conducted by the facility to meet MACT and SIP requirements. 
Therefore, we do not believe that the additional paperwork required by 
these proposed changes would constitute an undue burden to the 
facility.
    We estimate one regulated entity is currently subject to subpart 
TTT and will be subject to all proposed standards. This facility will 
have no capital costs associated with the information collection 
requirements in the proposed rule.
    The estimated recordkeeping and reporting burden after the 
effective date of the proposed rule is estimated to be 1,323 labor 
hours at a cost of $465,503. This estimate includes the cost of 
reporting, including reading instructions, and information gathering. 
Recordkeeping cost estimates include reading instructions, planning 
activities, monitoring plan development, conducting compliance 
monitoring, sampling and analysis and maintenance of rolling 3-month 
average data. The average hours and cost per regulated entity would be 
1,323 hours and $465,503 based on one facility response per year. 
Burden is defined at 5 CFR 1320.3(b).
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates, and any suggested methods for 
minimizing respondent burden, EPA has established a public docket for 
this rule, which includes this ICR, under Docket ID number EPA-HQ-OAR-
2004-0305. Submit any comments related to the ICR to EPA and OMB. See 
ADDRESSES section at the beginning of this notice for where to submit 
comments to EPA. Send comments to OMB at the Office of Information and 
Regulatory Affairs, Office of Management and Budget, 725 17th Street, 
NW., Washington, DC 20503, Attention: Desk Office for EPA. Since OMB is 
required to make a decision concerning the ICR between 30 and 60 days 
after February 17, 2011, a comment to OMB is best assured of having its 
full effect if OMB receives it by March 21, 2011. The final rule will 
respond to any OMB or public comments on the information collection 
requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions. For purposes 
of assessing the impacts of today's proposed rule on small entities, 
small entity is defined as: (1) A small business that is a small 
industrial entity as defined by the Small Business Administration's 
(SBA) regulations at 13 CFR 121.201; (2) a small governmental 
jurisdiction that is a government of a city, county, town, school 
district or special district with a population of less than 50,000; and 
(3) a small organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field.
    After considering the economic impacts of today's proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This 
proposed rule will not impose any requirements on small entities. This 
proposed rule is currently applicable to one operating facility that 
does not meet the definition of a small entity.
    We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

[[Page 9439]]

D. Unfunded Mandates Reform Act

    This proposed rule does not contain a federal mandate under the 
provisions of Title II of the Unfunded Mandates Reform Act of 1995 
(UMRA), 2 U.S.C. 1531-1538 for State, local, or tribal governments or 
the private sector. The proposed rule would not result in expenditures 
of $100 million or more for State, local, and tribal governments, in 
aggregate, or the private sector in any 1 year. The proposed rule 
imposes no enforceable duties on any State, local or tribal governments 
or the private sector. Thus, this proposed rule is not subject to the 
requirements of sections 202 or 205 of the UMRA.
    This proposed rule is also not subject to the requirements of 
section 203 of UMRA because it contains no regulatory requirements that 
might significantly or uniquely affect small governments because it 
contains no requirements that apply to such governments nor does it 
impose obligations upon them.

E. Executive Order 13132: Federalism

    This proposed rule does not have federalism implications. It will 
not have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. None of the facilities subject 
to this action are owned or operated by State governments, and, because 
no new requirements are being promulgated, nothing in this proposal 
will supersede State regulations. Thus, Executive Order 13132 does not 
apply to this proposed rule.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

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

    Subject to the Executive Order 13175 (65 FR 67249, November 9, 
2000) EPA may not issue a regulation that has tribal implications, that 
imposes substantial direct compliance costs, and that is not required 
by statute, unless the Federal government provides the funds necessary 
to pay the direct compliance costs incurred by tribal governments, or 
EPA consults with tribal officials early in the process of developing 
the proposed regulation and develops a tribal summary impact statement. 
EPA has concluded that this proposed rule will not have tribal 
implications, as specified in Executive Order 13175. It will not have 
substantial direct effect on tribal governments, on the relationship 
between the federal government and Indian tribes, or on the 
distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. 
Thus, Executive Order 13175 does not apply to this action.
    EPA specifically solicits additional comment on this proposed 
action from tribal officials.

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

    This proposed rule is not subject to Executive Order 13045 (62 FR 
19885, April 23, 1997) because it is not economically significant as 
defined in Executive Order 12866. However, the Agency does believe 
there is a disproportionate risk to children. Modeled ambient air lead 
concentrations from the one facility in this source category are in 
excess of the NAAQS for lead, which was set to ``provide increased 
protection for children and other at-risk populations against an array 
of adverse health effects, most notably including neurological effects 
in children, including neurocognitive and neurobehavioral effects.'' 73 
FR 67007. However, the control measures proposed in this notice will 
result in lead concentration levels that are in compliance with the 
lead NAAQS, thereby mitigating the risk of adverse health effects to 
children.

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

    This action is not a ``significant energy action'' as defined under 
Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 
28355, May 22, 2001), because it is not likely to have significant 
adverse effect on the supply, distribution, or use of energy. This 
action will not create any new requirements for sources in the energy 
supply, distribution, or use sectors.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies. The NTTAA directs EPA to provide 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards.
    This proposed rulemaking does not involve technical standards. 
Therefore, EPA is not considering the use of any voluntary consensus 
standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    To examine the potential for any environmental justice issues that 
might be associated with each source category, we evaluated the 
distributions of HAP-related cancer and non-cancer risks across 
different social, demographic, and economic groups within the 
populations living near the facilities where these source categories 
are located. The methods used to conduct demographic analyses for this 
rule are described in section IV.A of the preamble for this rule. The 
development of demographic analyses to inform the consideration of 
environmental justice issues in EPA rulemakings is an evolving science. 
The EPA offers the demographic analyses in today's rulemaking as 
examples of how such analyses might be developed to inform such 
consideration, and invites public comment on the approaches used and 
the interpretations made from the results, with the hope that this will 
support the refinement and improve utility of such analyses for future 
rulemakings.
    In the case of Primary Lead Processing, we focused on populations 
within 50 km of the one facility in this source category with emission 
sources subject to the MACT standard. More specifically, for these 
populations we

[[Page 9440]]

evaluated exposures to HAP which could result in cancer risks of 1-in-1 
million or greater, or population exposures to ambient air lead 
concentrations above the level of the NAAQS for lead. We compared the 
percentages of particular demographic groups within the focused 
populations to the total percentages of those demographic groups 
nationwide. The results of this analysis are documented in section 
V.B.1 (see Table 6), as well as in a technical report located in the 
docket for this rulemaking. In brief, although our analyses show that 
there is the potential for adverse environmental and human health 
effects from emissions of lead, it does not indicate any significant 
potential for disparate impacts to the specific demographic groups 
analyzed (see section V.B.1). Notably however, the proposed rule would 
require additional control measures to address the identified 
environmental and health risks and would therefore, decrease risks to 
any populations exposed to these sources.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Reporting and 
recordkeeping requirements, Lead.

    Dated: January 31, 2011.
Lisa P. Jackson,
Administrator.

    For reasons set out in the preamble, title 40, chapter I, of the 
Code of Federal Regulations is proposed to be amended:

PART 63--[AMENDED]

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

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

    2. Section 63.1541 is revised to read as follows:


Sec.  63.1541  Applicability.

    (a) The provisions of this subpart apply to any facility engaged in 
producing lead metal from ore concentrates. The category includes, but 
is not limited to, the following smelting processes: Sintering, 
reduction, preliminary treatment, refining and casting operations, 
process fugitive sources, and fugitive dust sources. The sinter process 
includes an updraft or downdraft sintering machine. The reduction 
process includes the blast furnace, electric smelting furnace with a 
converter or reverberatory furnace, and slag fuming furnace process 
units. The preliminary treatment process includes the drossing kettles 
and dross reverberatory furnace process units. The refining process 
includes the refinery process unit. The provisions of this subpart do 
not apply to secondary lead smelters, lead refiners, or lead remelters.
    (b) Table 1 of this subpart specifies the provisions of subpart A 
of this part that apply and those that do not apply to owners and 
operators of primary lead processors.
    3. Section 63.1542 is amended by:
    a. Adding in alphabetical order definitions for ``Affirmative 
defense,'' ``Lead refiner,'' ``Lead remelter,'' ``Primary lead 
processor,'' and ``Secondary lead smelter''.
    b. Removing the definition for ``Primary lead smelter''.
    c. Revising the definitions for ``Fugitive dust source,'' ``Furnace 
area,'' ``Malfunction,'' ``Materials storage and handling area,'' 
``Plant roadway,'' ``Process fugitive source,'' ``Refining and casting 
area,'' Sinter machine area,'' and ``Tapping location''.


Sec.  63.1542  Definitions.

* * * * *
    Affirmative defense means, in the context of an enforcement 
proceeding, a response or defense put forward by a defendant, regarding 
which the defendant has the burden of proof, and the merits of which 
are independently and objectively evaluated in a judicial or 
administrative proceeding.
* * * * *
    Fugitive dust source means a stationary source of hazardous air 
pollutant emissions at a primary lead processor resulting from the 
handling, storage, transfer, or other management of lead-bearing 
materials where the source is not part of a specific process, process 
vent, or stack. Fugitive dust sources include roadways, storage piles, 
materials handling transfer points, and materials transport areas.
    Furnace area means any area of a primary lead processor in which a 
blast furnace or dross furnace is located.
    Lead refiner means any facility that refines lead metal that is not 
located at a primary lead processor.
    Lead remelter means any facility that remelts lead metal that is 
not located at a primary lead processor.
    Malfunction means any sudden, infrequent, and not reasonably 
preventable failure of air pollution control and monitoring equipment, 
process equipment, or a process to operate in a normal or usual manner 
which causes, or has the potential to cause, the emission limitations 
in an applicable standard to be exceeded. Failures that are caused in 
part by poor maintenance or careless operation are not malfunctions.
    Materials storage and handling area means any area of a primary 
lead processor in which lead-bearing materials (including ore 
concentrate, sinter, granulated lead, dross, slag, and flue dust) are 
stored or handled between process steps, including areas in which 
materials are stored in piles, bins, or tubs, and areas in which 
material is prepared for charging to a sinter machine or smelting 
furnace or other lead processing operation.
* * * * *
    Plant roadway means any area of a primary lead processor that is 
subject to vehicle traffic, including traffic by forklifts, front-end 
loaders, or vehicles carrying ore concentrates or cast lead ingots. 
Excluded from this definition are employee and visitor parking areas, 
provided they are not subject to traffic by vehicles carrying lead-
bearing materials.
    Primary lead processor means any facility engaged in the production 
of lead metal from lead sulfide ore concentrates through the use of 
pyrometallurgical or other techniques.
    Process fugitive source means a source of hazardous air pollutant 
emissions at a primary lead processor that is associated with lead 
smelting, processing or refining but is not the primary exhaust stream 
and is not a fugitive dust source. Process fugitive sources include 
sinter machine charging locations, sinter machine discharge locations, 
sinter crushing and sizing equipment, furnace charging locations, 
furnace taps, and drossing kettle and refining kettle charging or 
tapping locations.
    Refining and casting area means any area of a primary lead 
processor in which drossing or refining operations occur, or casting 
operations occur.
    Secondary lead smelter means any facility at which lead-bearing 
scrap material, primarily, but not limited to, lead-acid batteries, is 
recycled into elemental lead or lead alloys by smelting.
* * * * *
    Sinter machine area means any area of a primary lead processor 
where a sinter machine, or sinter crushing and sizing equipment is 
located.
* * * * *
    Tapping location means the opening through which lead and slag are 
removed from the furnace.
    4. Section 63.1543 is revised to read as follows:


Sec.  63.1543  Standards for process and process fugitive sources.

    (a) No owner or operator of any existing, new, or reconstructed 
primary lead processor shall discharge or cause to be discharged into 
the atmosphere lead compounds in excess of 0.22

[[Page 9441]]

pounds per ton of lead metal produced from the aggregation of emissions 
discharged from air pollution control devices used to control emissions 
at primary lead processing facilities, including the sources listed in 
paragraphs (a)(1) through (a)(10) of this section.
    (1) Sinter machine;
    (2) Blast furnace;
    (3) Dross furnace;
    (4) Dross furnace charging location;
    (5) Blast furnace and dross furnace tapping location;
    (6) Sinter machine charging location;
    (7) Sinter machine discharge end;
    (8) Sinter crushing and sizing equipment;
    (9) Sinter machine area; and
    (10) Refining and casting, and furnace area.
    (b) No owner or operator of any existing, new, or reconstructed 
primary lead processor shall discharge or cause to be discharged into 
the atmosphere lead compounds in excess of 0.91 tons per year from the 
air pollution control devices used to control emissions from furnace 
area and refining and casting operations.
    (c) The process fugitive sources listed in paragraphs (a)(4) 
through (a)(8) of this section must be equipped with a hood and must be 
ventilated to a baghouse or equivalent control device. The hood design 
and ventilation rate must be consistent with American Conference of 
Governmental Industrial Hygienists recommended practices.
    (d) The sinter machine area must be enclosed in a building that is 
ventilated to a baghouse or equivalent control device at a rate that 
maintains a positive in-draft through any doorway opening.
    (e) Except as provided in paragraph (f) of this section, following 
the initial tests to demonstrate compliance with paragraphs (a)and (b) 
of this section, the owner or operator of a primary lead processor must 
conduct compliance tests for lead compounds on an quarterly basis (no 
later than 100 days following any previous compliance test).
    (f) If the 12 most recent compliance tests demonstrate compliance 
with the emission limit specified in paragraphs (a) and (b) of this 
section, the owner or operator of a primary lead processor shall be 
allowed up to 12 calendar months from the last compliance test to 
conduct the next compliance test for lead compounds.
    (g) The owner or operator of a primary lead processor must maintain 
and operate each baghouse used to control emissions from the sources 
listed in paragraphs (a)(1) through (a)(10) of this section such that 
the alarm on a bag leak detection system required under Sec.  
63.1547(c)(8) does not sound for more than five percent of the total 
operating time in a 6-month reporting period.
    (h) The owner or operator of a primary lead processor must record 
the date and time of a bag leak detection system alarm and initiate 
procedures to determine the cause of the alarm according to the 
corrective action plan required under Sec.  63.1547(f) within 1 hour of 
the alarm. The cause of the alarm must be corrected as soon as 
practicable.
    (i) At all times, the owner or operator must operate and maintain 
any affected source, including associated air pollution control 
equipment and monitoring equipment, in a manner consistent with safety 
and good air pollution control practices for minimizing emissions. 
Determination of whether such operation and maintenance procedures are 
being used will be based on information available to the Administrator 
which may include, but is not limited to, monitoring results, review of 
operation and maintenance procedures, review of operation and 
maintenance records, and inspection of the source.
    5. Section 63.1544 is revised to read as follows:


Sec.  63.1544  Standards for fugitive dust sources.

    (a) No owner or operator of any existing, new or reconstructed 
primary lead processor shall discharge or cause to be discharged into 
the atmosphere lead compounds that cause the concentration of lead in 
air to exceed 0.15 [micro]g/m\3\ on a 3-month rolling average measured 
at locations approved by the Administrator.
    (b) At all times, the owner or operator must operate and maintain 
any affected source, including associated air pollution control 
equipment and monitoring equipment, in a manner consistent with safety 
and good air pollution control practices for minimizing emissions. 
Determination of whether such operation and maintenance procedures are 
being used will be based on information available to the Administrator 
which may include, but is not limited to, monitoring results, review of 
operation and maintenance procedures, review of operation and 
maintenance records, and inspection of the source.
    6. Section 63.1545 is revised to read as follows:


Sec.  63.1545  Compliance dates.

    (a) Each owner or operator of an existing primary lead processor 
must achieve compliance with the requirements of this subpart no later 
than [DATE TWO YEARS FROM PUBLICATION OF THE FINAL RULE IN THE FEDERAL 
REGISTER].
    (b) Each owner or operator of a new primary lead processor must 
achieve compliance with the requirements of this subpart no later than 
[DATE 60 DAYS AFTER PUBLICATION OF THE FINAL RULE IN THE FEDERAL 
REGISTER] or startup, whichever is later.
    7. Section 63.1546 is revised to read as follows:


Sec.  63.1546  Performance testing.

    (a) The following procedures must be used to determine quarterly 
compliance with the emissions standard for lead compounds under Sec.  
63.1543(a) and (b) for existing sources:
    (1) Each owner or operator of existing sources listed in Sec.  
63.1543(a)(1) through (10) must determine the lead compound emissions 
rate, in units of pounds of lead per hour according to the following 
test methods in appendices of part 60 of this chapter:
    (i) Method 1 to appendix A-1 of 40 CFR part 60 must be used to 
select the sampling port location and the number of traverse points.
    (ii) Methods 2 and 2F of appendix A-1 and Method 2G of appendix A-2 
of 40 CFR part 60 must be used to measure volumetric flow rate.
    (iii) Methods 3, 3A, 3B of appendix A-2 of 40 CFR part 60 must be 
used for gas analysis.
    (iv) Method 4 of appendix A-3 of 40 CFR part 60 must be used to 
determine moisture content of the stack gas.
    (v) Method 12 of appendix A-5 or Method 29 of appendix A-8 of 40 
CFR part 60 must be used to determine lead emissions rate of the stack 
gas.
    (2) A performance test shall consist of at least three runs. For 
each test run with Method 12 of appendix A-5 or Method 29 of appendix 
A-8 of 40 CFR part 60, the minimum sample time must be 60 minutes and 
the minimum volume must be 1 dry standard cubic meter (35 dry standard 
cubic feet).
    (3) Performance tests shall be completed quarterly, once every 3 
months, to determine compliance.
    (4) The lead emission rate in pounds per quarter is calculated by 
multiplying the quarterly lead emission rate in pounds per hour by the 
quarterly plant operating time, in hours as shown in Equation 1:

[GRAPHIC] [TIFF OMITTED] TP17FE11.001


Where:

EPb = quarterly lead emissions, pounds per quarter;

[[Page 9442]]

ERPb = quarterly lead emissions rate, pounds per hour; 
and
QPOT = quarterly plant operating time, hours per quarter.

    (5) The lead production rate, in units of tons per quarter, must be 
determined based on production data for the previous quarter according 
to the procedures detailed in paragraphs (a)(5)(i) through (iv) of this 
section:
    (i) Total lead products production multiplied by the fractional 
lead content must be determined in units of tons.
    (ii) Total copper matte production multiplied by the fractional 
lead content must be determined in units of tons.
    (iii) Total copper speiss production multiplied by the fractional 
lead content must be determined in units of tons.
    (iv) Total quarterly lead production must be determined by summing 
the values obtained in paragraphs (a)(5)(i) through (a)(5)(iii) of this 
section.
    (6) To determine compliance with the production-based lead compound 
emission rate in Sec.  63.1543(a), the quarterly production-based lead 
compound emission rate, in units of pounds of lead emissions per ton of 
lead produced, is calculated as shown in Equation 2 by dividing lead 
emissions by lead production.

[GRAPHIC] [TIFF OMITTED] TP17FE11.002


Where:
CEPb = quarterly production-based lead compound emission 
rate, in units of pounds of lead emissions per ton of lead produced;
EPb = quarterly lead emissions, pounds per quarter; and
PPb = quarterly lead production, tons per quarter.

    (7) To determine quarterly compliance with the emissions standard 
for lead compounds under Sec.  63.1543(b), sum the lead compound 
emission rates for the current and previous three quarters for the 
sources in Sec.  63.1543 (a)(10) to determine compliance with Sec.  
63.1543(b), as determined in accordance with paragraphs (a)(1) through 
(a)(4) of this section.
    (b) Owner and operators must perform an initial compliance test to 
demonstrate compliance with the sinter building in-draft requirements 
of Sec.  63.1543(d) at each doorway opening in accordance with 
paragraphs (b)(1) through (b)(4) of this section.
    (1) Use a propeller anemometer or equivalent device.
    (2) Determine doorway in-draft by placing the anemometer in the 
plane of the doorway opening near its center.
    (3) Determine doorway in-draft for each doorway that is open during 
normal operation with all remaining doorways in their customary 
position during normal operation.
    (4) Do not determine doorway in-draft when ambient wind speed 
exceeds 2 meters per second.
    (c) Performance tests shall be conducted under such conditions as 
the Administrator specifies to the owner or operator based on 
representative performance of the affected source for the period being 
tested. Upon request, the owner or operator shall make available to the 
Administrator such records as may be necessary to determine the 
conditions of performance tests.
    8. Section 63.1547 is revised to read as follows:


Sec.  63.1547  Monitoring requirements.

    (a) Owners and operators of primary lead processors must prepare, 
and at all times operate according to, a standard operating procedures 
manual that describes in detail the procedures for inspection, 
maintenance, and bag leak detection and corrective action for all 
baghouses that are used to control process, process fugitive, or 
fugitive dust emissions from any source subject to the lead emission 
standards in Sec. Sec.  63.1543 and 63.1544, including those used to 
control emissions from general ventilation systems.
    (b) The standard operating procedures manual for baghouses required 
by paragraph (a) of this section must be submitted to the Administrator 
or delegated authority for review and approval.
    (c) The procedures specified in the standard operating procedures 
manual for inspections and routine maintenance must, at a minimum, 
include the requirements of paragraphs (c)(1) through (c)(8) of this 
section.
    (1) Weekly confirmation that dust is being removed from hoppers 
through visual inspection or equivalent means of ensuring the proper 
functioning of removal mechanisms.
    (2) Daily check of compressed air supply for pulse-jet baghouses.
    (3) An appropriate methodology for monitoring cleaning cycles to 
ensure proper operation.
    (4) Monthly check of bag cleaning mechanisms for proper functioning 
through visual inspection or equivalent means.
    (5) Quarterly visual check of bag tension on reverse air and 
shaker-type baghouses to ensure that bags are not kinked (kneed or 
bent) or laying on their sides. Such checks are not required for 
shaker-type baghouses using self-tensioning (spring loaded) devices.
    (6) Quarterly confirmation of the physical integrity of the 
baghouse through visual inspection of the baghouse interior for air 
leaks.
    (7) Quarterly inspection of fans for wear, material buildup, and 
corrosion through visual inspection, vibration detectors, or equivalent 
means.
    (8) Except as provided in paragraph (h) of this section, continuous 
operation of a bag leak detection system.
    (d) The procedures specified in the standard operating procedures 
manual for maintenance must, at a minimum, include a preventative 
maintenance schedule that is consistent with the baghouse 
manufacturer's instructions for routine and long-term maintenance.
    (e) The bag leak detection system required by paragraph (c)(8) of 
this section must meet the specifications and requirements of (e)(1) 
through (e)(8) of this section.
    (1) The bag leak detection system must be certified by the 
manufacturer to be capable of detecting particulate matter emissions at 
concentrations of 10 milligram per actual cubic meter (0.0044 grains 
per actual cubic foot) or less.
    (2) The bag leak detection system sensor must provide output of 
relative particulate matter loadings, and the owner or operator must 
continuously record the output from the bag leak detection system.
    (3) The bag leak detection system must be equipped with an alarm 
system that will sound when an increase in relative particulate loading 
is detected over a preset level, and the alarm must be located such 
that it can be heard or otherwise determined by the appropriate plant 
personnel.
    (4) Each bag leak detection system that works based on the 
triboelectric effect must be installed, calibrated, and maintained in a 
manner consistent with guidance provided in the U.S. Environmental 
Protection Agency guidance document ''Fabric Filter Bag Leak Detection 
Guidance'' (EPA-454/R-98-015). Other bag leak detection systems must be 
installed, calibrated, and maintained in a manner consistent with the 
manufacturer's written specifications and recommendations.
    (5) The initial adjustment of the system must, at a minimum, 
consist of establishing the baseline output by adjusting the 
sensitivity (range) and the averaging period of the device, and 
establishing the alarm set points and the alarm delay time.
    (6) Following initial adjustment, the owner or operator must not 
adjust the sensitivity or range, averaging period, alarm set points, or 
alarm delay time, except as detailed in the approved SOP required under 
paragraph (a) of this

[[Page 9443]]

section. In no event shall the sensitivity be increased by more than 
100 percent or decreased more than 50 percent over a 365-day period 
unless a responsible official certifies that the baghouse has been 
inspected and found to be in good operating condition.
    (7) For negative pressure, induced air baghouses, and positive 
pressure baghouses that are discharged to the atmosphere through a 
stack, the bag leak detector must be installed downstream of the 
baghouse and upstream of any wet acid gas scrubber.
    (8) Where multiple detectors are required, the system's 
instrumentation and alarm may be shared among detectors.
    (f) The standard operating procedures manual required by paragraph 
(a) of this section must include a corrective action plan that 
specifies the procedures to be followed in the event of a bag leak 
detection system alarm. The corrective action plan must include at a 
minimum, procedures to be used to determine the cause of an alarm, as 
well as actions to be taken to minimize emissions, which may include, 
but are not limited to, the following.
    (1) Inspecting the baghouse for air leaks, torn or broken bags or 
filter media, or any other condition that may cause an increase in 
emissions.
    (2) Sealing off defective bags or filter media.
    (3) Replacing defective bags or filter media, or otherwise 
repairing the control device.
    (4) Sealing off a defective baghouse compartment.
    (5) Cleaning the bag leak detection system probe, or otherwise 
repairing or maintaining the bag leak detection system.
    (6) Shutting down the process producing the particulate emissions.
    (g) The percentage of total operating time the alarm on the bag 
leak detection system sounds in a 6-month reporting period must be 
calculated in order to determine compliance with the five percent 
operating limit in Sec.  63.1543(h). The percentage of time the alarm 
on the bag leak detection system sounds must be determined according to 
paragraphs (g)(1) through (g)(3) of this section.
    (1) For each alarm where the owner or operator initiates procedures 
to determine the cause of an alarm within 1 hour of the alarm, 1 hour 
of alarm time must be counted.
    (2) For each alarm where the owner or operator does not initiate 
procedures to determine the cause of the alarm within 1 hour of the 
alarm, alarm time will be counted as the actual amount of time taken by 
the owner or operator to initiate procedures to determine the cause of 
the alarm.
    (3) The percentage of time the alarm on the bag leak detection 
system sounds must be calculated as the ratio of the sum of alarm times 
to the total operating time multiplied by 100.
    (h) Baghouses equipped with HEPA filters as a secondary filter used 
to control process or process fugitive sources subject to the lead 
emission standards in Sec.  63.1543 are exempt from the requirement in 
paragraph (c)(8) of this section to be equipped with a bag leak 
detector. The owner or operator of an affected source that uses a HEPA 
filter must monitor and record the pressure drop across the HEPA filter 
system daily. If the pressure drop is outside the limit(s) specified by 
the filter manufacturer, the owner or operator must take appropriate 
corrective measures, which may include, but not be limited to, the 
following:
    (1) Inspecting the filter and filter housing for air leaks and torn 
or broken filters.
    (2) Replacing defective filter media, or otherwise repairing the 
control device.
    (3) Sealing off a defective control device by routing air to other 
comparable control devices.
    (4) Shutting down the process producing the particulate emissions.
    (i) Owners and operators must monitor sinter machine building in-
draft to demonstrate continued compliance with the operating standard 
specified in Sec.  63.1543(d) in accordance with either paragraph 
(i)(1), (i)(2), or (i)(3) of this section.
    (1) Owners and operators must check and record on a daily basis 
doorway in-draft at each doorway in accordance with the methodology 
specified in Sec.  63.1546(b).
    (2) Owners and operators must establish and maintain baseline 
ventilation parameters which result in a positive in-draft according to 
paragraphs (i)(2)(i) through (i)(2)(iv) of this section.
    (i) Owners and operators must install, calibrate, maintain, and 
operate a monitoring device that continuously records the volumetric 
flow rate through each separately ducted hood; or install, calibrate, 
maintain, and operate a monitoring device that continuously records the 
volumetric flow rate at the control device inlet of each exhaust system 
ventilating the building. The flow rate monitoring device(s) can be 
installed in any location in the exhaust duct such that reproducible 
flow rate measurements will result. The flow rate monitoring device(s) 
must have an accuracy of plus or minus 10 percent over the normal 
process operating range and must be calibrated according to 
manufacturer's instructions.
    (ii) During the initial demonstration of sinter building in-draft, 
and at any time the owner or operator wishes to re-establish the 
baseline ventilation parameters, the owner or operator must 
continuously record the volumetric flow rate through each separately 
ducted hood, or continuously record the volumetric flow rate at the 
control device inlet of each exhaust system ventilating the building 
and record exhaust system damper positions. The owner or operator must 
determine the average volumetric flow rate(s) corresponding to the 
period of time the in-draft compliance determinations are being 
conducted.
    (iii) The owner or operator must maintain the volumetric flow 
rate(s) at or above the value(s) established during the most recent in-
draft determination at all times the sinter machine is in operation. 
Volumetric flow rate(s) must be calculated as a 15-minute average.
    (iv) If the volumetric flow rate is monitored at the control device 
inlet, the owner or operator must check and record damper positions 
daily to ensure they are in the positions they were in during the most 
recent in-draft determination.
    (3) An owner or operator may request an alternative monitoring 
method by following the procedures and requirements in Sec.  63.8(f) of 
the General Provisions.
    (j) Each owner or operator of new or modified sources listed under 
Sec.  63.1543 (a)(1) through (a)(10) must install, calibrate, maintain, 
and operate a continuous emission monitoring system (CEMS) for 
measuring lead emissions and a continuous emission rate monitoring 
system (CERMS) subject to Performance Specification 6 of Appendix B to 
part 60.
    (1) Each owner or operator of a source subject to the emissions 
limits for lead compounds under Sec.  63.1543(a) and (b) must install a 
CEMS for measuring lead emissions within 180 days of promulgation of 
performance specifications for lead CEMS.
    (i) Prior to promulgation of performance specifications for CEMS 
used to measure lead concentrations, an owner or operator must use the 
procedure described in Sec.  63.1546(a)(1) through (a)(7) of this 
section to determine compliance.
    (ii) [Reserved]
    (2) If a CEMS used to measure lead emissions is applicable, the 
owner or operator must install a CERMS with a sensor in a location that 
provides representative measurement of the exhaust gas flow rate at the 
sampling

[[Page 9444]]

location of the CEMS used to measure lead emissions, taking into 
account the manufacturer's recommendations. The flow rate sensor is 
that portion of the system that senses the volumetric flow rate and 
generates an output proportional to that flow rate.
    (i) The CERMS must be designed to measure the exhaust gas flow rate 
over a range that extends from a value of at least 20 percent less than 
the lowest expected exhaust flow rate to a value of at least 20 percent 
greater than the highest expected exhaust gas flow rate.
    (ii) The CERMS must be equipped with a data acquisition and 
recording system that is capable of recording values over the entire 
range specified in paragraph (b)(2)(i) of this section.
    (iii) Each owner or operator must perform an initial relative 
accuracy test of the CERMS in accordance with the applicable 
Performance Specification in Appendix B to part 60 of the chapter.
    (iv) Each owner or operator must operate the CERMS and record data 
during all periods of operation of the affected facility including 
periods of startup, shutdown, and malfunction, except for periods of 
monitoring system malfunctions, repairs associated with monitoring 
system malfunctions, and required monitoring system quality assurance 
or quality control activities (including, as applicable, calibration 
checks and required zero and span adjustments.
    (3) Each owner or operator must calculate the lead emissions rate 
in tons per year by summing all hours of CEMS data for a year to 
determine compliance with 63.1543(b).
    (i) When the CERMS are unable to provide quality assured data the 
following applies:
    (A) When data are not available for periods of up to 48 hours, the 
highest recorded hourly emission rate from the previous 24 hours must 
be used.
    (B) When data are not available for 48 or more hours, the maximum 
daily emission rate based on the previous 30 days must be used.
    (ii) [Reserved]
    (k) The owner or operator of each source subject to Sec.  
63.1544(a) must operate a continuous monitoring system for the 
measurement of lead compound concentrations in air.
    (1) The owner or operator must operate compliance monitors 
sufficient in number, location, and frequency of sample collection to 
detect expected maximum concentrations of lead compounds in air due to 
emissions from the affected source(s) in accordance with a written plan 
as described in (k)(2) of this paragraph and approved by the 
Administrator. The plan must include descriptions of the sampling and 
analytical methods used. The plan may take into consideration existing 
monitoring being conducted under a state monitoring plan in accordance 
with part 58 of this chapter.
    (2) The owner or operator must submit a written plan describing and 
explaining the basis for the design and adequacy of the compliance 
monitoring network, the sampling, analytical, and quality assurance 
procedures, and any other related procedures, and the justification for 
any seasonal, background, or other data adjustments within 45 days 
after the effective date of this subpart.
    (3) The Administrator at any time may require changes in, or 
expansion of, the monitoring program, including additional sampling and 
analytical protocols and network design.
    (l) If all rolling three-month average concentrations of lead in 
air measured by the compliance monitoring system are less than 50 
percent of the lead concentration in air limit in Sec.  63.1544(a) for 
three consecutive years, the owner or operator may submit a revised 
plan to reduce the monitoring sampling and analysis frequency (e.g., 
from daily to weekly). For any subsequent period, if any rolling three-
month average lead concentration in air measured at any monitor in the 
monitoring system exceeds 50 percent of the concentration limit in 
Sec.  63.1544(a), the owner or operator must resume monitoring pursuant 
to paragraph (k)(1) of this section at all monitors until another three 
consecutive years of lead concentration in air measurements less than 
50 percent of the lead concentration in air limit is demonstrated.
    9. Section 63.1548 is revised to read as follows:


Sec.  63.1548  Notification requirements.

    (a) The owner or operator of a primary lead processor must comply 
with the notification requirements of Sec.  63.9 of subpart A, General 
Provisions as specified in Table 1 of this subpart.
    (b) The owner or operator of a primary lead processor must submit 
the standard operating procedures manual for baghouses required under 
Sec.  63.1547(a) to the Administrator or delegated authority along with 
a notification that the primary lead processor is seeking review and 
approval of the manual and procedures. Owners or operators of existing 
primary lead processors must submit this notification no later than 
November 6, 2000. The owner or operator of a primary lead processor 
that commences construction or reconstruction after April 17, 1998, 
must submit this notification no later than 180 days before startup of 
the constructed or reconstructed primary lead processor, but no sooner 
than September 2, 1999.
    (c) The owner or operator of a primary lead processor must submit 
the compliance monitoring network plan required under Sec.  
63.1547(k)(2) to the Administrator or delegated authority along with a 
notification that the primary lead processor is seeking review and 
approval of the plan. Owners or operators of existing primary lead 
processors must submit this notification no later than 45 days after 
promulgation of this subpart. The owner or operator of a new, 
reconstructed, or modified primary lead processor must submit this 
notification no later than 180 days before startup of the constructed 
or reconstructed primary lead processor.
    10. Section 63.1549 is revised to read as follows:


Sec.  63.1549  Recordkeeping and reporting requirements.

    (a) The owner or operator of a primary lead processor must comply 
with the recordkeeping requirements of Sec.  63.10 of subpart A, 
General Provisions as specified in Table 1 of this subpart.
    (b) In addition to the general records required by paragraph (a) of 
this section, each owner or operator of a primary lead processor must 
maintain for a period of 5 years, records of the information listed in 
paragraphs (b)(1) through (b)(10) of this section.
    (1) Production records of the weight and lead content of lead 
products, copper matte, and copper speiss.
    (2) Records of the bag leak detection system output.
    (3) An identification of the date and time of all bag leak 
detection system alarms, the time that procedures to determine the 
cause of the alarm were initiated, the cause of the alarm, an 
explanation of the actions taken, and the date and time the cause of 
the alarm was corrected.
    (4) Any recordkeeping required as part of the requirements 
described in the compliance monitoring system plan required under Sec.  
63.1547(k)(2).
    (5) Any recordkeeping required as part of the practices described 
in the standard operating procedures manual for baghouses required 
under Sec.  63.1547(a).
    (6) If an owner or operator chooses to demonstrate continuous 
compliance with the sinter building in-draft requirement under Sec.  
63.1543(d) by employing the method allowed in Sec.  63.1547(i)(1), the 
records of the daily doorway in-draft checks, an

[[Page 9445]]

identification of the periods when there was not a positive in-draft, 
and an explanation of the corrective actions taken.
    (7) If an owner or operator chooses to demonstrate continuous 
compliance with the sinter building in-draft requirement under Sec.  
63.1543(d) by employing the method allowed in Sec.  63.1547(i)(2), the 
records of the output from the continuous volumetric flow monitor(s), 
an identification of the periods when the 15-minute volumetric flow 
rate dropped below the minimum established during the most recent in-
draft determination, and an explanation of the corrective actions 
taken.
    (8) If an owner or operator chooses to demonstrate continuous 
compliance with the sinter building in-draft requirement under Sec.  
63.1543(d) by employing the method allowed in Sec.  63.1547(i)(2), and 
volumetric flow rate is monitored at the baghouse inlet, records of the 
daily checks of damper positions, an identification of the days that 
the damper positions were not in the positions established during the 
most recent in-draft determination, and an explanation of the 
corrective actions taken.
    (9) Records of the occurrence and duration of each malfunction of 
operation (i.e., process equipment) or the air pollution control 
equipment and monitoring equipment.
    (10) Records of actions taken during periods of malfunction to 
minimize emissions in accordance with Sec. Sec.  63.1543(i) and 
63.1544(e), including corrective actions to restore malfunctioning 
process and air pollution control and monitoring equipment to its 
normal or usual manner of operation.
    (c) Records for the most recent 2 years of operation must be 
maintained on site. Records for the previous 3 years may be maintained 
off site.
    (d) The owner or operator of a primary lead processor must comply 
with the reporting requirements of Sec.  63.10 of subpart A, General 
Provisions as specified in Table 1 of this subpart.
    (e) In addition to the information required under Sec.  63.10 of 
the General Provisions, the owner or operator must provide semi-annual 
reports containing the information specified in paragraphs (e)(1) 
through (e)(9) of this section to the Administrator or designated 
authority.
    (1) The reports must include records of all alarms from the bag 
leak detection system specified in Sec.  63.1547(e).
    (2) The reports must include a description of the actions taken 
following each bag leak detection system alarm pursuant to Sec.  
63.1547(f).
    (3) The reports must include a calculation of the percentage of 
time the alarm on the bag leak detection system sounded during the 
reporting period pursuant to Sec.  63.1547(g).
    (4) If an owner or operator chooses to demonstrate continuous 
compliance with the sinter building in-draft requirement under Sec.  
63.1543(d) by employing the method allowed in Sec.  63.1547(i)(1), the 
reports must contain an identification of the periods when there was 
not a positive in-draft, and an explanation of the corrective actions 
taken.
    (5) If an owner or operator chooses to demonstrate continuous 
compliance with the sinter building in-draft requirement under Sec.  
63.1543(d) by employing the method allowed in Sec.  63.1547(i)(2), the 
reports must contain an identification of the periods when the 15-
minute volumetric flow rate(s) dropped below the minimum established 
during the most recent in-draft determination, and an explanation of 
the corrective actions taken.
    (6) If an owner or operator chooses to demonstrate continuous 
compliance with the sinter building in-draft requirement under Sec.  
63.1543(d) by employing the method allowed in Sec.  63.1547(i)(2), and 
volumetric flow rate is monitored at the baghouse inlet, the reports 
must contain an identification of the days that the damper positions 
were not in the positions established during the most recent in-draft 
determination, and an explanation of the corrective actions taken.
    (7) The reports must contain a summary of the records maintained as 
part of the practices described in the standard operating procedures 
manual for baghouses required under Sec.  63.1547(a), including an 
explanation of the periods when the procedures were not followed and 
the corrective actions taken.
    (8) The reports must contain a summary of the compliance monitoring 
results for the required reporting period, including an explanation of 
any periods when the procedures outlined in the compliance monitoring 
system plan required by Sec.  63.1547(k)(2) were not followed and the 
corrective actions taken.
    (9) If there was a malfunction during the reporting period, the 
report shall also include the number, duration, and a brief description 
for each type of malfunction which occurred during the reporting period 
and which caused or may have caused any applicable emission limitation 
to be exceeded. The report must also include a description of actions 
taken by an owner or operator during a malfunction of an affected 
source to minimize emissions in accordance with Sec. Sec.  63.1543(i) 
and 63.1544(b), including actions taken to correct a malfunction.
    11. Section 63.1550 is revised to read as follows:


Sec.  63.1550  Delegation of authority.

    (a) In delegating implementation and enforcement authority to a 
State under section 112(1) of the Act, the authorities contained in 
paragraph (b) of this section must be retained by the Administrator and 
not transferred to a State.
    (b) Authorities which will not be delegated to States: No 
restrictions.
    12. Section 63.1551 is added to read as follows:


Sec.  63.1551  Affirmative defense for exceedance of emission limit 
during malfunction.

    In response to an action to enforce the standards set forth in this 
subpart you may assert an affirmative defense to a claim for civil 
penalties for exceedances of such standards that are caused by 
malfunction, as defined in 40 CFR 63.2. Appropriate penalties may be 
assessed, however, if you fail to meet your burden of proving all the 
requirements in the affirmative defense. The affirmative defense shall 
not be available for claims for injunctive relief.
    (a) To establish the affirmative defense in any action to enforce 
such a limit, you must timely meet the notification requirements in 
paragraph (b) of this section, and must prove by a preponderance of 
evidence that:
    (1) The excess emissions:
    (i) Were caused by a sudden, short, infrequent, and unavoidable 
failure of air pollution control and monitoring equipment, process 
equipment, or a process to operate in a normal or usual manner; and
    (ii) Could not have been prevented through careful planning, proper 
design or better operation and maintenance practices; and
    (iii) Did not stem from any activity or event that could have been 
foreseen and avoided, or planned for; and
    (iv) Were not part of a recurring pattern indicative of inadequate 
design, operation, or maintenance; and
    (2) Repairs were made as expeditiously as possible when the 
applicable emission limitations were being exceeded. Off-shift and 
overtime labor were used, to the extent practicable to make these 
repairs; and
    (3) The frequency, amount and duration of the excess emissions 
(including any bypass) were minimized to the maximum extent practicable 
during periods of such emissions; and

[[Page 9446]]

    (4) If the excess emissions resulted from a bypass of control 
equipment or a process, then the bypass was unavoidable to prevent loss 
of life, severe personal injury, or severe property damage; and
    (5) All possible steps were taken to minimize the impact of the 
excess emissions on ambient air quality, the environment and human 
health; and
    (6) All emissions monitoring and control systems were kept in 
operation if at all possible; and
    (7) All of the actions in response to the excess emissions were 
documented by properly signed, contemporaneous operating logs; and
    (8) At all times, the facility was operated in a manner consistent 
with good practices for minimizing emissions; and
    (9) A written root cause analysis has been prepared to determine, 
correct and eliminate the primary causes of the malfunction and the 
excess emissions resulting from the malfunction event at issue. The 
analysis shall also specify, using best monitoring methods and 
engineering judgment, the amount of excess emissions that were the 
result of the malfunction.
    (b) Notification. The owner or operator of the facility 
experiencing an exceedance of its emission limit(s) during a 
malfunction shall notify the Administrator by telephone or facsimile 
(FAX) transmission as soon as possible, but no later than two business 
days after the initial occurrence of the malfunction, if it wishes to 
avail itself of an affirmative defense to civil penalties for that 
malfunction. The owner or operator seeking to assert an affirmative 
defense shall also submit a written report to the Administrator within 
30 days of the initial occurrence of the exceedance of the standard in 
this subpart to demonstrate, with all necessary supporting 
documentation, that it has met the requirements set forth in paragraph 
(a) of this section.
    12. Table 1 to Subpart TTT of Part 63 is revised to read as 
follows:

               Table 1 to Subpart TTT of Part 63--General Provisions Applicability to Subpart TTT
----------------------------------------------------------------------------------------------------------------
             Reference                  Applies to subpart TTT                      Explanation
----------------------------------------------------------------------------------------------------------------
Sec.   63.1.......................  Yes.                           .............................................
Sec.   63.2.......................  Yes.                           .............................................
Sec.   63.3.......................  Yes.                           .............................................
Sec.   63.4.......................  Yes.                           .............................................
Sec.   63.5.......................  Yes.                           .............................................
Sec.   63.6(a), (b), (c)..........  Yes.                           .............................................
Sec.   63.6 (d)...................  No...........................  Section reserved.
Sec.   63.6(e)(1)(i)..............  No...........................  See Sec.   63.1543(i) and Sec.   63.1544(b)
                                                                    for general duty requirement.
Sec.   63.6(e)(1)(ii).............  No.                            .............................................
Sec.   63.6(e)(1)(iii)............  Yes.                           .............................................
Sec.   63.6(e)(2).................  No...........................  Section reserved.
Sec.   63.6(e)(3).................  No.                            .............................................
Sec.   63.6(f)(1).................  No.                            .............................................
Sec.   63.6(g)....................  Yes.                           .............................................
Sec.   63.6(h)....................  No...........................  No opacity limits in rule.
Sec.   63.6(i)....................  Yes.                           .............................................
Sec.   63.6(j)....................  Yes.                           .............................................
Sec.   63.7(a)-(d)................  Yes.                           .............................................
Sec.   63.7(e)(1).................  No...........................  See Sec.   63.1546(c).
Sec.   63.7(e)(2)-(e)(4)..........  Yes.                           .............................................
Sec.   63.7(f), (g), (h)..........  Yes.                           .............................................
Sec.   63.8(a)-(b)................  Yes.                           .............................................
Sec.   63.8(c)(1)(i)..............  No.                            .............................................
Sec.   63.8(c)(1)(ii).............  Yes.                           .............................................
Sec.   63.8(c)(1)(iii)............  No.                            .............................................
Sec.   63.8(c)(2)-(d)(2)..........  Yes.                           .............................................
Sec.   63.8(d)(3).................  Yes, except for last           .............................................
                                     sentence.
Sec.   63.8(e)-(g)................  Yes.                           .............................................
Sec.   63.9(a), (b), (c), (e),      Yes.                           .............................................
 (g), (h)(1) through (3), (h)(5)
 and (6), (i) and (j).
Sec.   63.9(f)....................  No.                            .............................................
Sec.   63.9(h)(4).................  No...........................  Reserved.
Sec.   63.10(b)(2)(i).............  No.                            .............................................
Sec.   63.10(b)(2)(ii)............  No...........................  See Sec.   63.1549(b)(9) and (10) for
                                                                    recordkeeping of occurrence and duration of
                                                                    malfunctions and recordkeeping of actions
                                                                    taken during malfunction.
Sec.   63.10(b)(2)(iii)...........  Yes.                           .............................................
Sec.   63.10(b)(2)(iv)-(b)(2)(v)..  No.                            .............................................
Sec.   63.10(b)(2)(vi)-(b)(2)(xiv)  Yes.                           .............................................
Sec.   63.(10)(b)(3)..............  Yes.                           .............................................
Sec.   63.10(c)(1)-(9)............  Yes.                           .............................................
Sec.   63.10(c)(10)-(11)..........  No...........................  See Sec.   63.1549(b)(9) and (10) for
                                                                    recordkeeping of malfunctions.
Sec.   63.10(c)(12)-(c)(14).......  Yes.                           .............................................
Sec.   63.10(c)(15)...............  No.                            .............................................
Sec.   63.10(d)(1)-(4)............  Yes.                           .............................................

[[Page 9447]]

 
Sec.   63.10(d)(5)................  No...........................  See Sec.   63.1549(e)(9) for reporting of
                                                                    malfunctions.
Sec.   63.10(e)-((f)..............  Yes.                           .............................................
Sec.   63.11......................  No...........................  Flares will not be used to comply with the
                                                                    emission limits.
Sec.   63.12 through 63.15........  Yes.                           .............................................
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2011-2866 Filed 2-16-11; 8:45 am]
BILLING CODE 6560-50-P