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                   SUMMARY OF PUBLIC COMMENTS AND RESPONSES

                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                     U.S. Environmental Protection Agency
                 Office of Air Quality Planning and Standards
                     Sector Policies and Programs Division
                 Research Triangle Park, North Carolina 27711
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                              DRAFT  -  11-4-2011
                                       
                                       
                                       
The primary contact regarding questions or comments on this document is:

Nathan Topham
U.S. Environmental Protection Agency
OAQPS/Sector Policies and Programs Division
Metals and Inorganic Chemicals Group (D243-02)
Research Triangle Park, North Carolina 27711

Email: topham.nathan@epa.gov
                               TABLE OF CONTENTS

Section	Page No.

1.0	INTRODUCTION	7
2.0	LIST OF COMMENTERS	7
3.0	SUMMARY OF PUBLIC COMMENTS	3
3.1	Emissions Limits and Guidelines	3
3.1.1	Statutory Basis	3
3.1.2	Fugitive Emissions Limits	13
a.	General	13
b.	Ambient Monitoring Requirements	20
c.	Rule Clarifications	21
3.1.3	Stack Emissions Limits	23
a.	Lead and Other Metal HAP	23
b.	Total Hydrocarbons (THC) and Dioxins and Furans (D/F)	40
c.	Mercury	46
3.2	Risk Assessment	47
3.2.1	Risk Assessment Methodology	47
3.2.2	Emissions Used	89
3.3	Baseline Emissions Estimates	91
3.3.1	Fugitive Emissions Estimates	91
3.3.2	Stack Emissions Estimates	93
3.4	Compliance Timeline	94
3.5	Performance Testing	99
3.5.1	Testing Frequency	99
3.5.2	Continuous Emissions Monitoring Systems (CEMS)	99
3.5.3	Bag Leak Detection Systems (BLDS)	103
3.6	Typographical Corrections	104
3.7	SSM and Affirmative Defense	104
3.8	Request for Comment Period Extension	118
3.9	Miscellaneous	118

List of Acronyms and Abbreviations

Acronyms
ABR
Association of Battery Recyclers
ATSDR
Agency for Toxic Substances and Disease Registry
BLDS
Bag Leak Detection System
CAA
Clean Air Act
CEMS
Continuous Emissions Monitoring System
CERCLA
Comprehensive Environmental Response, Compensation, and Liability Act of 1980
CL
Confidence Limit
CSEFH
Child-Specific Exposure Factors Handbook
CTE
Central Tendency Exposure
D/F
Dioxins and Furans
EFH
Exposure Factors Handbook
EPA
U. S. Environmental Protection Agency
FR
Federal Register
GACT
Generally Available Control Technology
HAP
Hazardous Air Pollutant
HEM
Human Exposure Model
HEPA
High Efficiency Particulate Air Filter
HI
Hazard Index
HON
Hazardous Organic NESHAP
HQ
Hazard Quotient
IRIS
Integrated Risk Information System
LOAEL
Lowest Observable Adverse Effect Level
MACT
Maximum Achievable Control Technology
MEI
Maximum Exposed Individual
MIR
Maximum Individual Risk
NAAQS
National Ambient Air Quality Standards
NEI
National Emissions Inventory
NESHAP
National Emission Standards for Hazardous Air Pollutants
NOAEL
No Observable Adverse Effect Level
OAQPS
Office of Air Quality Planning and Standards
ODW
Office of Drinking Water
OHEA
Office of Health and Environmental Assessment
PB-HAP
Persistent Bioaccumulative Hazardous Air Pollutant
PSD
Prevention of Significant Deterioration
PTFE
polytetrafluoroethylene
RCRA
Resource Conservation and Recovery Act
REL
Recommended Exposure Limit
REL
Recommended Exposure Limit
RfC
Reference Concentrations
RME
Reasonable Maximum Exposure
RQ
Reportable Quantity (CERCLA)
RTR
Risk and Technology Review
SCAQMD
South Coast Air Quality Management District
SIC
Standard Industrial Classification
SIP
State Implementation Plan
SOP
Standard Operating Procedure
SSM
Startup, Shutdown, and Malfunction
TEF
Toxic Equivalency Factor
THC
Total Hydrocarbon
TOSHI
Target Organ specific Hazard Index
TRI
Toxic Release Inventory
UPL
Upper Predictive Limit
URE
Unit Risk Exposure
WESP
Wet Electrostatic Precipitator
WHO
World Health Organization


INTRODUCTION
      On May 19, 2011, EPA proposed revisions to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Secondary Lead Smelters. Some significant comments and responses appear in the preamble to the final rule. This document contains summaries of the public comments that the EPA received on the proposed standards that are not summarized and addressed in the preamble to the final rule. Copies of all comments submitted are available at the EPA docket Center Public Reading Room. Comment letters and transcripts of the public hearings are also available electronically through http://www.regulations.gov by searching Docket ID EPA-HQ-OAR-2011-0344.
LIST OF COMMENTERS
      The EPA received 30 comment letters on the proposed NESHAP for secondary lead smelters before the comment period closed on July 25, 2011. All comments are contained in Docket EPA-HQ-OAR-2011-0344. The commenter, affiliation, and item number in Docket EPA-HQ-OAR-2011-0344 is listed in Table 2-1.
      
Table 2-1. Public Comments Received by July 25, 2011 for National Emissions Standards for Hazardous Air Pollutants (NESHAP): Secondary Lead Smelters, Proposed Rule Docket EPA EPA-HQ-OAR-2011-0344

                                       
                                   Docket ID
                                       
                                 Commenter ID
                                     Code

Commenter and Affiliation
                          EPA-HQ-OAR-2011-0344-0069.1
                                      69
Robert Steinwurtzel, Attorney, Baker Hostetler on behalf of the Association of Battery Recyclers
                          EPA-HQ-OAR-2011-0344-0070.1
                                      70
Robert Steinwurtzel, Attorney, Baker Hostetler on behalf of the Association of Battery Recyclers
                           EPA-HQ-OAR-2011-0344-0071
                                      71
Dennis Lane,  Attorney, Stinson Morrison Hecker LLP on behalf of Doe Run Resources Corporation
                           EPA-HQ-OAR-2011-0344-0072
                                      72
Frederick A. Ganster, Director, Environmental Health and Safety, Exide Technologies
                           EPA-HQ-OAR-2011-0344-0073
                                      73
Michael Carr, Vice President, Johnson Controls Battery Group, Inc.
                          EPA-HQ-OAR-2011-0344-0074.1
                                      74
Robert Steinwurtzel, Attorney, Baker Hostetler on behalf of the Association of Battery Recyclers
                           EPA-HQ-OAR-2011-0344-0075
                                      75
Michael Carr, Vice President, Johnson Controls Battery Group, Inc.
                           EPA-HQ-OAR-2011-0344-0076
                                      76
Robert Steinwurtzel, Attorney, Baker Hostetler on behalf of the Association of Battery Recyclers
                          EPA-HQ-OAR-2011-0344-0078.1
                                      78
Kerry Russell, Attorney, Russell and Rodriguez on behalf of the City of Frisco, Texas
                          EPA-HQ-OAR-2011-0344-0079.1
                                      79
John Cooper, President, Cooper Environmental Services
                           EPA-HQ-OAR-2011-0344-0080
                                      80
James Kavanaugh, Director, Air Pollution Control Program, Missouri Department of Natural Resources
                          EPA-HQ-OAR-2011-0344-0081.1
                                      81
John Cooper, President, Cooper Environmental Services
                           EPA-HQ-OAR-2011-0344-0082
                                      82
Jerry Campbell, Director, Air Management Division, Environmental Protection Commission of Hillsborough County, Tampa, FL
                           EPA-HQ-OAR-2011-0344-0083
                                      83
Anonymous
                           EPA-HQ-OAR-2011-0344-0084
                                      84
John Cooper, President, Cooper Environmental Services
                           EPA-HQ-OAR-2011-0344-0085
                                      85
Krag Petterson, Pall Corporation
                           EPA-HQ-OAR-2011-0344-0086
                                      86
G. Vinson Hellwig and Robert Colby, Co-Chairs, National Association of Clean Air Agencies Air Toxics Committee
                          EPA-HQ-OAR-2011-0344-0087.1
                                      87
Timothy J. LaFond, Environmental Committee Chairman, Battery Council International
                          EPA-HQ-OAR-2011-0344-0088.1
                                      88
Billy Nichols, Principal Engineer, URS Corporation on behalf of Sanders Lead Company
                          EPA-HQ-OAR-2011-0344-0089.1
                                      89
Michael Carr, Vice President, Johnson Controls Battery Group, Inc.;  John Tapper, Chief Operating Officer, Gopher Resources, EnviroFocus Technologies; Dean A. Rossi, Vice President  -  Global EHS, Exide Technologies; Richard Leiby, Vice President, Metals Operations, East Penn Manufacturing; N. Kenneth Campbell, Executive Vice President, Sanders Lead Company
                          EPA-HQ-OAR-2011-0344-0090.1
                                      90
Michael Carr, Vice President, Johnson Controls Battery Group, Inc.
                          EPA-HQ-OAR-2011-0344-0091.1
                                      91
Dennis Lane,  Attorney, Stinson Morrison Hecker LLP on behalf of Doe Run Resources Corporation
                          EPA-HQ-OAR-2011-0344-0092.1
                                      92
J. Jared Snyder, Assistant Commissioner for Air Resources, Climate Change and Energy, New York Department of Environmental Conservation
                          EPA-HQ-OAR-2011-0344-0093.1
                                      93
Richard Leiby, Vice President, Metals Operations, East Penn Manufacturing
                          EPA-HQ-OAR-2011-0344-0094.1
                                      94
Dean A. Rossi, Vice President  -  Global EHS, Exide Technologies
                          EPA-HQ-OAR-2011-0344-0095.1
                                      95
Homer P. Hine, Vice President, RSR Corporation
                          EPA-HQ-OAR-2011-0344-0096.3
                                      96
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers
                         EPA-HQ-OAR-2011-0344-0096-A5
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment A
                         EPA-HQ-OAR-2011-0344-0096-A6
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment B
                         EPA-HQ-OAR-2011-0344-0096-A7
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment C
                         EPA-HQ-OAR-2011-0344-0096-A8
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment D
                         EPA-HQ-OAR-2011-0344-0096-A9
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment E
                         EPA-HQ-OAR-2011-0344-0096-A10
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment F
                         EPA-HQ-OAR-2011-0344-0096-A11
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment G
                         EPA-HQ-OAR-2011-0344-0096-A12
                               N/A (Attachment)
Robert Steinwurtzel and Mark DeLaquil, Attorneys, Baker Hostetler on behalf of the Association of Battery Recyclers Attachment H
                         EPA-HQ-OAR-2011-0344-0097-A2
                                      97
Myra C. Reece, Chief, Bureau of Air Quality, South Carolina Department of Health and Environmental Control
                           EPA-HQ-OAR-2011-0344-0098
                                      98
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club
                         EPA-HQ-OAR-2011-0344-0099-A1
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A2
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A3
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A4
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A5
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A6
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A7
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A8
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A9
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0099-A10
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A1
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A2
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A3
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A4
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A5
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A6
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A7
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A8
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0100-A9
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0101-A1
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0101-A2
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0101-A3
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0101-A4
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0101-A5
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0102-A1
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0102-A2
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0102-A3
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0102-A4
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0102-A5
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0102-A6
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0103-A1
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                         EPA-HQ-OAR-2011-0344-0103-A2
                               N/A (Attachment)
Earthjustice, on behalf of California Communities Against Toxics, Desert Citizens Against Pollution, Missouri Coalition for the Environment, Natural Resources Defense Council, and Sierra Club Attachment
                           EPA-HQ-OAR-2011-0344-0111
                                      111
Matt Todd, Chair, The Residual Risk Coalition
                           EPA-HQ-OAR-2011-0344-0120
                                      120
Krag Petterson, Pall Corporation
                           EPA-HQ-OAR-2011-0344-0127
                                      127
Robert Steinwurtzel, Attorney, Baker Hostetler on behalf of the Association of Battery Recyclers
                           EPA-HQ-OAR-2011-0344-0130
                                      130
Robert Steinwurtzel, Attorney, Baker Hostetler on behalf of the Association of Battery Recyclers


SUMMARY OF PUBLIC COMMENTS
      Comments received on the proposed amendments to the secondary lead smelting rule that were not presented in the preamble to the final rule are summarized in the following sections along with EPA's responses.  In many instances, commenters provided additional documents as background information or otherwise in support of their comments. Those documents are contained in the docket to this rulemaking but are not summarized here. 
Emissions Limits and Guidelines
      Statutory Basis
      Comment:  Comments received from the Secondary Lead Smelting industry (Commenters 90, 91, 94, 96) challenged what they characterize as the dual regulation under both the National Ambient Air Quality Standards (NAAQS) and the NESHAP programs.  These commenters made the following claims:
      The provisions of CAA §§ 112(b)(2) and 112 (b)(7) preclude EPA from setting emission standards or work practices under CAA § 112 for lead and other criteria pollutants.  EPA has listed both lead and its compounds as a criteria pollutant under CAA § 108(a), for which NAAQS have been promulgated at all relevant times.  EPA has already embarked on a path to reduce the health risks of exceeding the lead NAAQS through CAA §109 regulation and the statute precludes EPA from seeking to reduce the same risk via a CAA § 112 route.
      Further risk reduction through revision of the NESHAP is not required taking into account the emissions controls required to achieve the NAAQS, therefore a NESHAP revision is not required to protect public health or prevent environmental effects, and so is not authorized.
      Emissions will be reduced completely independent of the NESHAP because states must assemble SIPs without being able to wait for NESHAP completion.
      The two standards would be effectively duplicative, and revising the NESHAP to address risk is not required if EPA considers emissions controls required through implementation of the NAAQS.  The NAAQS already ensures that risks are addressed with an adequate margin of safety.
      Congress gave elemental lead special treatment in the Clean Air Act, providing a separate and unique prohibition against EPA listing elemental lead as a hazardous air pollutant under this subsection.  EPA is effectively regulating under 112 (f)(2) based on the toxicity of elemental lead, and this violates section 112 (b)(7) of the Act which prohibits listing of elemental lead as a HAP.  EPA is not permitted to count lead atoms from lead compounds and create a NESHAP that governs total lead in all chemical forms, but may establish standards for individual and unique lead compounds when appropriate based on toxicity or other factors. 
      The proposed rule negates the SIP process for lead NAAQS attainment.  The proposed MACT rule accelerates Lead NAAQS attainment without any explanation of why acceleration is appropriate. 
      
      Response: With respect to the comment that the EPA may not address lead compounds in section 112 (d) rules, the EPA notes that the EPA issued MACT rules regulating lead compounds in 1997 and no commenter objected to the approach.  EPA did not reopen the issue in this rule, or otherwise reconsider its long-established approach.  Consequently, EPA believes this issue to have been resolved long since. See Medical Waste inst. v. EPA, 645 F. 3d 420, 427 (D.C. Cir. 2011) and Portland Cement Ass'n v. EPA, No. 10-1358 (D.C. Cir. 2011) (slip op. at 17) (both holding that issues not raised when NESHAP is first promulgated may not be raised when those standards are revised).
      If any substantive response is considered to be necessary, the lead emitted from secondary lead smelting is lead compounds, a HAP listed by Congress in section 112 (b)(1)  The commenter did not provide data to refute this.   Nor has the EPA listed elemental lead as a HAP either explicitly or effectively. The EPA does not accept the commenter's argument that the EPA is implicitly regulating elemental lead under section 112 (f) standards by evaluating risk from exposure to lead compounds emitted by secondary lead facilities. The EPA's obligation under section 112 (f) is to evaluate whether unacceptable risk to human health or the environment from a source category's emissions remains after the EPA has promulgated section 112 (d) MACT standards for the source category and to amend those standards if unacceptable risk remains.  The standards thus build off of the section 112 (d) standards, and as just noted, it has long been resolved that those standards apply to lead compounds and not to elemental lead.  The commenter also invokes section 112 (f)(6) which states that "[i]n establishing standards for the control of unique chemical substances under this subsection without CAS numbers [of which "lead compounds" are an example], the Administrator shall establish such standards with respect to the health and environmental effects of the substances actually emitted by sources and direct transformation byproducts of such emissions...".  The EPA has done so here, evaluating risks with respect to actual emissions of lead compounds from secondary lead sources.  See 76 FR at 29035.
      In addition, the rule regulates other HAP metals for which lead serves as a surrogate.  See National Lime Ass'n  v. EPA, 233 F. 3d 625, 637-39 (D.C. Cir. 2000) (permissible for EPA to use a criteria pollutant as a surrogate for HAP). The commenter does not question the use of lead as a surrogate for other metal HAP, and did not question use of that approach in the 1997 NESHAP. Consequently, the standards for lead also rest on this independent justification.
      Other commenters noted that the lead NAAQS applies to "lead and its compounds", referring to section 50.12 (a) of the EPA's regulations. The commenter further notes that under the NAAQS, the EPA measures and hence regulates lead by summing the elemental lead present in lead and its compounds, and placing a limit on the ambient level of total lead in any form separate from other elements to which it may be chemically bound. The commenter argues that in light of this, regulation of lead compounds in this rule is necessarily in tension with implementation of the NAAQS. Noting the prohibition on listing "elemental lead" as a hazardous air pollutant in section 112 (b)(7), the commenter argues that the section 112 (b)(7) prevents the EPA from regulating lead identically under section 112 as under the NAAQS, and thus that "the EPA may not regulate lead compounds in an identical manner as the NAAQS program - by placing limits on lead in all of its chemical forms, whether bound to other atoms or not."  The commenter views Congressional intent as assuring that section 112 rules do not interfere with implementation of the lead NAAQS.	The EPA does not view section 112 (b)(1), (b)(2), and (b)(7) as unambiguously mandating the result the commenter seeks. Congress listed lead compounds as a HAP in section 112 (b)(1), meaning that the EPA is compelled to issue section 112 standards for that HAP. Section 112 (b)(2) forbids the EPA from adding to the list of HAP any pollutant listed under section 108 (a) (i.e. a criteria pollutant), but the EPA has not added such a pollutant to the HAP list. Nor has the EPA listed "elemental lead" as a hazardous air pollutant, in violation of section 112 (b)(7). Regulating lead compounds is simply not the same thing as listing elemental lead (and even the commenter notes that the term "elemental lead" is ambiguous in this context.)  Finally, the EPA does not accept that the commenter's ultimate point  that Congress intended that section 112 standards for lead compounds must be tailored in such a way as not to interfere with NAAQS implementation "because the NAAQS already ensures that risks are addressed with an adequate margin of safety". First, as noted in other comment responses in section 3.2 of this document and in section V.A of the preamble to the final rule, the legal standard under section 112 (f) is not the same as under sections  109 (b) and (d), so a NAAQS cannot be presumed to provide an acceptable level of risk with an ample margin of safety (and the EPA has therefore provided an independent justification here for use of the lead primary NAAQS as a measure of risk acceptability, and conducted an independent ample margin of safety analysis). Moreover, the commenter's argument makes little sense in the context of the technology-based standards under section 112(d) where consideration of risk, and hence of the protections afforded by the lead NAAQS, are irrelevant. Ultimately, the commenter's approach would deprive the section 112 (b)(1) listing of lead compounds of meaning (given that virtually all emitted lead from industrial processes is expected to be lead compounds due to chemical reactions), and EPA thus does not accept it.
      The commenters raise a number of issues regarding the relation of this rule to the lead NAAQS. First, the fact that control of emissions from secondary lead sources has positive implications for attaining the lead NAAQS does not mean that EPA is impermissibly controlling emissions of a criteria pollutant.  As just stated, section 112 (b) makes clear that regulating lead compounds under section 112 standards is not only permissible but mandated.  The fact that such controls aid in attaining a NAAQS is a collateral benefit of the rule, not a prohibition on adopting it.  (Similarly, this rule may aid in attaining the PM NAAQS but this doesn't mean that the rule impermissibly regulates emissions of PM.)  Nor does the rule negate the section 110 SIP process whereby states develop implementation plans for attaining and maintaining the NAAQS.    That process will necessarily go forward and states may look to the emission reductions from this rule as part of the SIP process (just as emission reductions from EPA mobile source controls or controls on stationary sources can be invoked in SIPs for PM and ozone).  In this regard, EPA's discussion in the preamble of the relationship of this rule to implementation of the lead NAAQS (76 FR at 29603), which a commenter mistakenly takes as showing that this rule was adopted to assure attainment of the lead NAAQS, was intended only as a `good government' type of discussion to show that the timing of this rule could fit in with the NAAQS implementation process.  We repeat that this rule rests on the exclusive authority of sections 112 (d) and (f), and not on sections 107, 110 or any other provision applicable to NAAQS implementation.  Put another way, section 112 of the CAA explicitly requires the EPA to perform the reviews that form the basis of these rule amendments and to act in accord with the results of those reviews. The requirements of the final rule are necessary to achieve acceptable risk with an ample margin of safety and to prevent adverse environmental effects (and are also "necessary" within the meaning of section 112 (d)(6) of the Act). The measures that facilities are required to implement to achieve those requirements should also have positive effects on areas attaining and maintaining the lead NAAQS, but the standards are required and justified under section 112 (f) and (d)(6) whether or not that were the case. Ironically, the EPA could well interfere with the SIP process if it accepted the commenter's (incorrect) argument that EPA must take into account "NAAQS-mandated emissions reductions" (See EPA-HQ-OAR-2011-0344-0096, p. 31). The lead NAAQS itself does not mandate anything.  It is an air quality standard only.  States determine how to implement it.  The suggestion that EPA attribute emission reductions to the SIP process which lies within states' authority, and which has not yet occurred, therefore would be unwarranted speculation at best and impermissible interference at worst.  
      In the proposed rule, the lead NAAQS, a health based standard, was used by EPA to determine whether or not there was unacceptable risk from lead compounds emitted by secondary lead smelting sources.   It is permissible for EPA to look to the lead NAAQS as a measure of acceptable risk (see responses at page 64 of this document and section V.A of the final rule preamble), and doing so does not mean that EPA is using this rule to implement the lead NAAQS.  Rather, EPA must, and has, independently justified the use of the lead primary NAAQS as a reasonable measure for ascertaining acceptability or unacceptability of emissions of lead from this source category, within the meaning of section 112 (f)(2) of the Act.  Given that modeled ambient lead concentrations resulting from emissions from the facilities in the source category were greater than the lead NAAQS, it was concluded at proposal, and for the final rule, that risk was unacceptable, and that it would continue to be unacceptable until the NAAQS was met. See 76 FR at 29054.  Once we determined a level of emissions that result in risks being acceptable, under the two-step residual risk decision process, the EPA then considered additional controls that might further reduce risk to achieve an ample margin of safety considering cost and feasibility, and determined that there were none.  We repeat that this process implements section 112 (f) of the Act, and is not part of NAAQS implementation.
      Comment: Commenter 91 stated that the use of lead concentration in air does not fit within the meaning of "emission standard" as used in CAA 112(d), (f), or (h).  The NAAQS addresses ambient air quality, not source emissions, and as such, does not limit the quantity rate or concentration of emissions from a particular source.  Ambient monitoring measures something other than emissions at and from a source, and cannot be equated with or used to determine compliance with an emission standard. 
      Response: The commenters mistake the purpose of the fenceline monitoring compliance alternative in the proposed rule. The proposed rule provided that fugitive emissions would need to be addressed by work practice standards (as is allowed under section 112(h)(1)). Finally, it proposed to establish the option for a fenceline monitoring requirement to ensure that the work practice standards adequately address fugitive emissions consistent with the requirements of section 112(f) as an alternative to totally enclosing fugitive generating processes. However, the EPA is not adopting this proposed compliance option so the comment is essentially moot.  
      Comment: Commenter 90 challenged the decision to establish MACT floors for reverberatory, rotary and electric furnaces not collocated with blast furnaces. In the final rule published on June 13, 1997, EPA determined that no THC limits (and thus no other organic HAP limits) would apply to theses furnace types.  Thus, EPA effectively established the MACT floor for these sources.  According to the commenter, "EPA has already established the MACT floor for D/F and THC as addressed in CAA §§112(d)(2) and (3) as it applies for reverberatory, rotary and electric arc furnaces, and no additional "setting of the floor" is possible under these sections at this time.  Commenter 96 further stated that MACT standards pursuant to section 112(d)(3) "have never been intended as having the "inexorable downward ratcheting effect.""
      Commenter 90 also stated that EPA cited an improper legal basis for setting new emission limits for THC and Dioxins and Furans. The commenter stated that "EPA may revise a prior determination only as necessary according to explicit statutory criteria... The CAA is not intended to allow the Agency to revisit previously-established MACT standards in effort to fill in the gaps."  EPA stated in the preamble to the proposed rule that "because the 1997 NESHAP did not include emissions limits, we are proposing emissions standards for dioxins and furans pursuant to CAA section 112(d)(3)."  According to the commenter,  "This explanation makes it clear that EPA is invoking 112(d)(2) and (3) directly as authority to amend Subpart X as if a MACT standard for these sources does not already exist...EPA lacks authority for setting any new standards under CAA §§112(d)(2) and(d)(3)." 
      The commenter further stated that "The RTR Proposed Rule does not attempt to predicate its decision to set controls for THC and D/F (for sources other than blast furnaces), on the Court's decision in Sierra Club v EPA, 479 F.3d 875(D.C. Cir. 2007) (Brick MACT).  Having made the determination not only to rely on Sierra Club in support of the proposed rule, EPA may not change course without issuing a supplemental proposal and allowing an opportunity for public comment....EPA would have to justify why the decisions reflected in the current standards are wrong and why the new standards meet the required criteria that EPA must satisfy in issuing MACT standards under CAA 112(d)(2) and (3).  EPA has not made either showing in the RTR Proposed rule."  The commenter noted that EPA cited National Lime v. EPA, 233 F. 3d 625, 624 (DC Cir. 2000), in support of its decision to set emission standards for THC and dioxins and furans from subcategories other than blast furnaces.  The commenter points out, however, that as set forth in Sierra Club, EPA has not interpreted National Lime as requiring the Agency to set such standards.  Furthermore, National Lime does not control because the decision did not address EPA's authority to set standards pursuant to section 112(d)(6) and 112(f).  Instead, National Lime addressed what emission standards the agency should propose in a MACT rulemaking pursuant to deadlines set forth in section 112(e).
      Commenter 90 also raised the issue that challenges to the MACT standards are to be raised within 60 days of their promulgation and that facilities regulated by Subpart X have already made capital investments to meet the existing MACT standards.  EPA should justify why the decisions reflected in the current standards are wrong and why the new standards meet the criteria under CAA §§ 112(d)(2) and (3). 
      Commenter 96 made a similar argument that the proposed rule lacks a sufficient legal basis to support its proposed promulgation of emission standards for dioxins and furans and THC.  According to the commenter, "Clean Air Act §§112(d)(6) allows EPA to revise only emission standards promulgated under this section" 42 U.S.C. §7412(d)(6).  EPA has not promulgated emission standards for dioxins and furans or THC (for furnaces other than blast furnaces), so it may not promulgate revised standards for these substances under that authority".  
      Commenter 90 stated that the proposed rule improperly reset MACT floors pursuant to the CAA 112 (d)(6) process and that the CAA does not require EPA to recalculate MACT floors.  According to the commenter:  
      
      The RTR Proposed Rule's basis for revising the lead emission MACT floors pursuant to CAA § 112(d)(6) is that the Agency "believe[s] that these proposed revisions, identical to those proposed under CAA section 112(f)(2), are cost effective revisions that reflect the level of control achievable in practice by a well-performing fabric filter." 76 Fed. Reg. at 29,059-60. Whether a control is cost-effective and achievable is relevant to the availability of a particular control, but does not answer the antecedent question of whether or not imposing such control is necessary to protect public health or the environment in light of other legal requirements that the CAA applies to the secondary lead smelting industry.
      
      Response:  In Medical Waste Institute v. EPA, 645 F. 3d 420, 425-27 (D.C. Cir. 2011), the D.C. Circuit held that EPA may permissibly amend improper MACT determinations, including amendments to  improperly promulgated floor determinations, using its authority under section 112 (d) (2) and (3).  (The lack of a remand on these issues here is a distinction without a difference.  The absence of standards for these HAP is not proper.  National Lime, 233 F. 3d at 633-34; see also Medical Waste Incinerator, 645 F. 3d at  426 (resetting MACT floor, based on post-compliance data, permissible when originally-established floor was improperly established, and permissibility of EPA's action does not turn on whether the prior standard was remanded or vacated).  The D.C. Circuit's December 9, 2011in Portland Cement Ass'n v. EPA (D.C. Cir. No. 10-1358) confirms that EPA is not constrained by section 112 (d)(6) and it may reassess its standards more often, including revising existing floors if need be. Slip op. p. 17. The commenters are thus incorrect that section 112 (d)(6) provides the exclusive authority to address THC, dioxin and mercury emissions here.  Put another way, if EPA did not adopt a proper MACT standard initially, it is not amending a MACT standard but adopting one for the first time.  That is the case here for THC (from some furnace types), dioxin and mercury emissions.  Here, EPA adopted no MACT standard at all for these HAP, an approach soundly rejected by the D.C. Circuit in National Lime, 233 F. 3d at 633-34.   Consequently, EPA is not barred from making MACT floor determinations and issuing MACT standards pursuant to section 112 (d)(2) and (3) here.
      Comment: Commenters 90 and 96 claim that the EPA's proposed regulation of lead compounds under the NESHAP program conflicts with its regulation of lead under the PSD program.  The commenters point out that that section 112(b)(6) of the CAA prescribes the regulation of pollutants listed under section 112, including lead compounds, under PSD, and that section 112(b)(7) precludes listing elemental lead under section 112. 
      The commenters allege that the EPA has previously suggested in a PSD rulemaking that it counts the lead portion of lead compounds towards PSD significance levels for lead.  See 67 Fed. Reg. 80,186, 80,239 (Dec. 31, 2002).  Thus, the commenters allege that, because the EPA can disaggregate the "elemental lead" portion of lead compounds for purposes of PSD, it can also disaggregate the toxic effects of lead from lead compounds, and the commenters allege that this is required for the EPA to avoid regulating elemental lead under section 112 (f) and (d)(6) standards.  Thus, the commenters claim that there is a conflict between the proscriptions of sections 112(b)(7), and the regulation of lead compounds on the basis of their lead toxicity pursuant to sections 112.
The commenters claim that, in the alternative, if the EPA concludes that it may regulate lead compounds on the basis of their lead toxicity pursuant to section 112, then the EPA cannot consider the lead aspect of lead compounds for purposes of regulating elemental lead under PSD.  The commenters argue that, to conclude otherwise would mean that lead compounds are subject to duplicative regulation under both the NESHAP program and PSD, which the commenters claim is unlawful.
      Response: The commenters are correct in stating that section 112 (b)(7) forbids the EPA from listing elemental lead as a hazardous air pollutant and that by extension this precludes the EPA from regulating elemental lead as a HAP under section 112 (d) and (f) standards. The commenters are further correct in stating that section 112 (b)(6) prohibits the agency from subjecting hazardous air pollutants that are listed under section 112(b)(1) and (2) of the Act to PSD regulation.  However, the EPA disagrees that these provisions prevent the EPA from regulating lead compounds under section 112 (d) and (f), and disagrees that any actions taken under the PSD program are inconsistent with regulation of lead compounds in this rule.  Furthermore, to the extent that any response is deemed necessary, the EPA disagrees that any actions taken under the PSD rules with respect to elemental lead and lead compounds is inconsistent with section 112 (b)(6).
      First, as explained in the first response in this section 3.1.1, this rule (like the 1997 NESHAP) regulates lead compounds, not elemental lead.  Lead compounds are listed HAP which the EPA must regulate under section 112 (see section 112 (b)(1) item 106423), and objections to the EPA doing so are untimely by at least 14 years (the date of the initial NESHAP for this source category).  
      The commenter's comparison with actions under the PSD program are misplaced. In the PSD rule, for purposes of assessing whether sources were emitting at the statutory rate thresholds or volumetric concentrations, the commenter claims that the EPA determined that the weight of elemental lead could be disaggregated from lead compounds, citing 67 Fed. Reg. at 80,329.  While the EPA did not use the term "disaggregation" in the cited rule preamble, the EPA did communicate that it counts the lead component of lead compounds in determining the mass of lead emitted from a source. Nevertheless, in relying on this EPA statement here, the commenter is comparing apples to oranges. The present rulemaking deals with issues of toxicity and risk, not weight. What is involved is not a straight-forward counting exercise but a determination of risk posed by exposure to lead compounds. It is entirely reasonable for the EPA to consider the toxicity of lead compounds based on elemental lead toxicity, and indeed, there are no suggestions on this record that there is any technical error in doing so.  
      The commenter's suggestion that the EPA amend its PSD rules is well beyond the scope of this proceeding, and the EPA is not reconsidering, reexamining, reassessing, or otherwise reopening its PSD rules in any way. To the extent that any response to the comments relating to PSD is considered to be necessary, the EPA disagrees with the commenter's assertion that sections 112(b)(6) and (7) preclude the EPA from both regulating lead compounds on account of their elemental lead toxicity and considering the lead component of lead compounds when calculating levels of lead emissions for purposes of PSD.  Although section 112(b)(6) prevents the agency from subjecting hazardous air pollutants that are listed under section 112(b)(1) and (2) of the Act to PSD regulation, the EPA has interpreted  section 112(b)(6) to permit the regulation of a HAP listed in section 112 to the extent it is a constituent or precursor of a more general pollutant that is subject to PSD regulation. This interpretation was outlined in the 1991 New Source Review (NSR) Transitional Guidance, John S. Seitz (March 11, 1991), which was issued to address changes made to the new source review program in the Clean Air Act Amendments of 1990.  In that memo, the EPA explained that "[a]ny hazardous air pollutants listed in section 112(b)(1) which are regulated as constituents of a more general pollutant listed under section 108 of the Act are still subject to PSD as part of the more general pollutant."  Id. at 2.  The EPA further explained that lead compounds are subject to the exception described "[l]ead compounds are exempt from Federal PSD by Title III, but the elemental lead portion of lead compounds (as tested for in 40 CFR Part 60, Appendix A, Method 12) is still considered a criteria pollutant subject to the lead NAAQS and still regulated under PSD."  Id. at 3.  
      The EPA relied on the reasoning contained in the 1991 guidance memo when it proposed to retain its interpretation of section 112 that permits the lead component of lead compounds to be subject to PSD regulation as a part of the regulation of lead generally. Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NSR), 61 Fed. Reg. 38250, 38310 (July 23, 1996).  In the PSD rule to which the commenter cites, the EPA finalized this position:  "When any pollutant listed under section 112 of the Act is also a constituent or precursor of a more general pollutant that is regulated under section 108 of the Act, that listed pollutant may be regulated under NSR but only as part of regulation of the general pollutant."  Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NSR): Baseline Emissions Determination, Actual-to-Future-Actual Methodology, Plantwide Applicability Limitations, Clean Units, Pollution Control Projects, 67 Fed. Reg. at 80,240 (Dec. 31, 2002).  The EPA reiterated in that final rule that it would continue to consider the lead component of lead compounds to be a constituent or precursor of lead in the atmosphere, as consistent with the 1991 guidance memo.  Thus, the EPA has consistently determined that there is no conflict between regulating lead compounds under section 112 and considering the lead component of lead compounds for purposes of PSD with respect to the lead NAAQS, so long as the lead compounds themselves are not subject to PSD regulation.
      Fugitive Emissions Limits
   a. General
      Comment: Commenter 98 stated that EPA's proposed standard for fugitive lead emissions does not meet the requirements of section 112(d)(6).  According to the commenter, "EPA must set a stronger standard for fugitive dust emissions of lead, which make up a significant amount of the lead emissions for this source category".  The commenter contends that neither proposed alternative complies with section 112(d)(6).  The alternative of total enclosures "imposes a numerical limit only on the emissions vented to a stack from the total enclosure and not for the other work practices.  This will not ensure the necessary reduction of fugitive emissions at these facilities... EPA must set a numerical limit that applies to emissions resulting from the work practice standards in addition to setting a numerical limit for emissions from total enclosure (vented to a stack).  The fugitive emissions standard for the additional work practice should be based on modeling of ambient levels achieved as a result of optimal implementation of those work practices.  This standard may not simply replicate the limit of the lead NAAQS."
      For the alternative of monitoring lead concentrations in air plus work practices, the commenter stated that "Simply replicating the lead NAAQS through monitoring... is not a valid substitute for doing an actual 112(d)(3) and 112(d)(6) analysis based on achievable emission reductions.... EPA should set a numerical limit for emissions resulting from the additional work practice standards."
      Response:  In the final rule, we have removed the proposed option for facilities to implement lead monitoring in lieu of installing total enclosures. Therefore, the final rule requires secondary lead facilities to construct total enclosures for fugitive emission sources and to conduct a list of prescribed fugitive emission control work practices. The commenter's objections to the alternative monitoring approach are thus moot.  
      We disagree that the final fugitive emission standard does not meet the requirements of section 112(d)(6).  First, it is clearly permissible for EPA to set work practice standards to control fugitive emissions.   According to section 112(h) of the CAA, "...if it is not feasible in the judgment of the Administrator to prescribe or enforce an emission standard for control of a hazardous air pollutant or pollutants, the Administrator may, in lieu thereof, promulgate a design, equipment, work practice, or operational standard, or combination thereof, which in the Administrator's judgment is consistent with the provisions of subsection (d) or (f) of this section."  It is not feasible to enforce a numerical emissions standard for fugitive emissions from secondary lead smelters that are not vented to a stack since these emissions are not directly measurable (this is why they are termed `fugitive emissions').  However, we note that fugitive emissions which are enclosed, captured, and vented to a control device are subject to the numerical standard for individual stacks and are count against the facility-wide stack emission limit for lead, and thus are effectively subject to a numerical limitation.
      The commenter suggests that the standards  -  which require total enclosure of lead bearing materials  -  could be made stricter still.  We are not aware of a more effective means to control fugitive emissions than total enclosure of process areas that generate fugitive emissions and requiring that those enclosures be vented to a control device. We are also requiring work practice standards along with those enclosures that will ensure that there are no opportunities for any fugitive dust generated inside those enclosures to be carried outside. The final rule includes every work practice possible that would limit fugitive lead emissions without creating workplace safety hazards.   (After the public comment process, EPA's statement at proposal  -  "[w]e acknowledge that there may be other control measures and alternative approaches that we have not identified that are effective in reducing fugitive emissions at other facilities (76 FR at 29056/3) -- no longer holds.  After considering the public comments, we are not aware of any such measures.) 
      The commenter also indicates that any work practice standards should be reinforced by some type of numeric standard tied to fenceline monitoring.  EPA is not adopting this type of provision.  The EPA evaluated available preexisting ambient monitoring data and compared the ambient concentrations with the degree of enclosure and presence of work practice standards similar to those included in this final rule. This comparison demonstrated that the measures required in this final rule will achieve reductions in ambient lead concentrations to levels below the NAAQS. See Summary of Ambient Lead Monitoring Data Around Secondary Lead Smelting Facilities, which is available in the docket (EPA-HQ-OAR-2011-0344). Monitoring in perpetuity for the NESHAP to observe this already demonstrated fact will impose burden without any further environmental benefit. The requirements in the NESHAP include measures for determining continuous compliance that are sufficient to ensure that emissions, and ambient concentrations, will remain low. The requirement to totally enclose buildings and maintain them under negative pressure with ventilation to a control device ensures that fugitive emissions will not escape buildings through doorways or other openings. Work practice standards, such as those requiring vehicle washing prior to leaving a total enclosure ensure that lead bearing dust within buildings is not inadvertently transported outside of the structure and re-entrained later. The requirements in the final rule that prevent fugitive emissions from escaping buildings in the first place make it unnecessary to include ambient monitoring. 
      Section 112(h) of the CAA further states that "In the event the Administrator promulgates a design or equipment standard under this subsection, the Administrator shall include as part of such standard such requirements as will assure the proper operation and maintenance of any such element of design or equipment."  We believe that the monitoring and recordkeeping required for the work practices and the measurement of building differential pressure ensure "proper operation and maintenance" of the work practice requirements for fugitive emissions that are not vented to a stack.  Hence, the final standards for fugitive lead emissions are clearly warranted under sections 112(f) and 112(d)(6).
      We note that we did evaluate the work practices already employed by some facilities as well as South Coast Air Quality Management District (SCAQMD) rule 1420.1 and while some of the work practices adopted in this final rule are similar to some requirements of SCAQMD, that rule included a number of measures that are geared towards specific challenges posed by conditions in the Los Angeles area. For example, roof washing is required in the SCAQMD rule, and while this measure may be appropriate for the warm, dry climate in Los Angeles, it is inappropriate for areas with higher levels of precipitation (e.g. Puerto Rico) or for areas with cold climates (e.g. New York, Minnesota) where falling ice could present safety hazards for workers. The final rule includes all of the enclosure and work practice requirements for fugitive emissions that were deemed necessary to provide the public with an ample margin of safety while ensuring that those requirements do not create redundant requirements or workplace hazards.
      Comment: Several commenters (90, 96, 91, 93) suggested that EPA had not adequately explained the emissions benefits of the proposed work practice requirements, and that EPA lacks any legitimate basis for its estimate of emissions reductions that would result.  Commenter 96 stated that there was no documentation in the record explaining how EPA derived an estimate of 4.2 tons per year attributed specifically to the work practices.  The commenter notes their assumption that the underlying basis of the anticipated total aggregate fugitive emissions reduction of 9.5 tons per year is based on the emissions estimates in the RTR emissions dataset, an assumption that the commenter asserts is incorrect for two reasons.  First, EPA's methodology to calculate the 9.5 tons per year is wrong because EPA overestimated fugitive emissions for Exide Frisco whose estimates form the basis for estimated emissions from the remaining secondary lead sources.  Second, the Exide Frisco emissions estimates do not contain estimates of emissions for many of the activities that the proposed work practice requirements are aimed at addressing.
      The commenters further note that the agency does not identify which facilities undertake all the design standards and work practices.  According to the commenters, "EPA's failure to include this information in the record contravenes Clean Air Act § 307(d)."  The commenter further stated that "EPA"s failure to include this information underlying the Proposed Rule's design standards and work practices is prejudicial to the ABR because the Association cannot meaningfully comment on whether EPA has correctly described and transformed into proposed legal requirements the practices on which these proposed work practice standards are predicated."  Commenters 90 and 96 offered that "In order for the design standards and work practices to be consistent with Clean Air Act §112(d)(2), they collectively must be undertaken by, or at least consistent with, the best performing five sources in the industry."  The commenter further stated that "EPA cannot predicate a risk-based CAA 112(f) emission standard for metal HAPs on compliance with the NAAQS absent a specific factual determination by the Administrator that the designs and work practice standards collectively are necessary to meet ...public health criteria."
      EPA stated in its preamble to the proposed standards that "these controls are necessary to ensure that three-month rolling average lead concentration near the boundaries at all facilities in this source category do not exceed the lead NAAQS."  Commenters 90 and 96 commented that "This rationale is incorrect because several facilities meet the lead NAAQS at all monitors near their property boundaries without applying these measures."  The commenter provides Gopher Resources, East Penn, RSR (NY), and RSR (IN) as examples of facilities that are currently and regularly meeting the NAAQS at monitors near their boundaries without applying all the proposed work practices.  The commenter state that the facilities do NOT conduct the following proposed work practices: cleaning of pavement with a water application rate of at least 0.48 gallons/square yard, rooftop washing, and inspection of battery storage areas more frequently than once per week.
      Commenter 96 noted that although the SCAQMD issued a rule that requires sources to undertake some of the work practices proposed by EPA, "EPA did not state that it was relying on the SCAQMD rule, nor did it introduce that rule or any administrative materials underlying its consideration into the record. "  The commenter argues that introducing the record of the SCAQMD rule "would have shown that it was potentially justified only in light of the unique local concerns in that area..."  The commenter stated that "EPA has no basis for concluding that the work practices that the SCAQMD required would be effective at all outside the specific conditions in that region..."
      Commenter 90 agrees with EPA's proposed use of an SOP manual for fugitive emissions control procedures but requested that EPA reassess the overall strategy related to fugitive emissions.  The commenter "recommends that the RTR proposed rule require that each facility's SOP manual require consideration of the various work practices and total enclosure requirements...but not require implementation of specific requirements without consideration of site-specific factors...  Ambient monitoring at each facility will be the test to verify that fugitive dust control measures are effective..."   The commenter requests that EPA specifically exclude the following areas from requirements to address in an SOP manual: intact battery storage, lead ingot product handling where fugitive lead dust is not generated, handling of storm water and wastewater treatment residuals, and clean battery casing plastic handling.
      Commenter 93 stated that the work practice requirements represent a cost burden disproportionate with any perceived benefit, and are unnecessary for facilities to operate in compliance with the current lead NAAQS.  The commenter requested that the mandatory work practice requirements be removed from Subpart X.
      Response:  The technical document describing the technology review for this source category clearly described the methodology used to calculate the emissions benefits in the proposed work practice requirements. See Summary of the Technology Review for the Secondary Lead Smelting Source Category, which is available in docket ID EPA-HQ-OAR-2011-0344. We used the same methodology to calculate the emissions reductions as was used to calculate the baseline fugitive emissions for each facility.  The commenter is correct that there was a miscalculation at proposal in the baseline fugitive emissions estimates. See section V.E of the final rule preamble. We have corrected the baseline fugitive emission estimates and the subsequent emissions reductions associated with the proposed work practice. We have done additional modeling for the source category based on the updated fugitive emission estimates (reflecting slightly reduced emissions from fugitive emissions) and the conclusions remain the same as at proposal. Lead emissions still remain unacceptably high and revisions to the standard are necessary to provide acceptable risk with an ample margin of safety. See Residual Risk Assessment for the Secondary Lead Smelting Source Category, available in docket ID EPA-HQ-OAR-2011-0344. The EPA has also adjusted the emission reduction estimates resulting from the revisions to the standard. While the cost effectiveness of the metal HAP emission reductions has decreased slightly from the estimate at proposal, we believe that the revisions to the standard to address fugitive emissions are still cost effective and necessary  under section 112(d)(6).  
      The commenters note that in order for the design and work practice standards to be consistent with section 112(d)(2), they must be undertaken by the best performing five sources in industry.  However, the work practices are being adopted under section 112(d)(6) (and under section 112 (f)(2), as noted in the next paragraph), not 112(d)(2). Section 112(d)(6) does not require a MACT floor-like calculation involving the best performing five sources, but rather is based on developments in control practices, processes and technologies and may reflect considerations of cost (including cost effectiveness) of adopting additional controls and non-air and energy impacts associated with additional controls.  All of the work practices included in the final rule that were not in the original NESHAP are performed at least by the well-controlled Exide Technologies facility in Vernon and Quemetco facility in City of Industry that are subject to the SCAQMD 1420.1 rule, while some of these work practices are conducted by many other facilities (e.g., pavement or groundcover of facility grounds, transport of dust in sealed containers or conveyor systems).  
      The work practices are also being adopted under section 112(f)(2).  The preamble to the proposed rule clearly described that our analyses indicated that the proposed work practices were necessary to achieve lead concentrations near the boundaries of the facilities that are at, or below the lead NAAQS, a benchmark of risk acceptability in this rule. 76 FR at 29056/3. Section 112(f)(2) of the CAA also does not require a MACT floor calculation based on the performance of the top 12% of sources (or top 5 sources for a category with less than 30 facilities). In fact, if section 112 (f)(2) standards are required, the standards must result in acceptable risk  whether or not any sources in the category are currently performing at that level.
      With regard to the facilities described by the commenter as meeting the lead NAAQS without implementation of the proposed work practices and therefore should not require further control under section 112 (f) (2), we note that this rule implements section 112 (f)(2), not the lead primary NAAQS. Section 112 (f)(2) standards apply on a source category-wide basis, so the commenter's suggestion that EPA adopt facility-by-facility standards predicated on the individual area's attainment status is not legally permissible. (The work practice standards are also `necessary' under section 112 (d)(6) given these affordable and cost effective industry practices and developments.) Nevertheless, as a result of these and other comments received on the proposed rulemaking, we have removed some of the proposed specific work practices mentioned by the commenter that present safety hazards or are redundant as noted in section V.C of the final rule preamble.
      We agree that the SCAQMD rule may contain some work practices that are most effective at the two facilities in southern California. However, the final list of work practice standards will ensure that fugitive dust is not generated outside of total enclosures which are vented to control devices, thereby ensuring the public is protected from these emissions with an ample margin of safety. Each facility must also develop and submit a SOP to their local permitting authority for approval to ensure that the facility properly implements the enclosure requirements and work practice standards.
      Comment: Commenters 90 and 96 proposed regulatory language to address the specific issues identified for the alternative to total enclosures (§63.544(d)(1)  -  (d)(8)).
      Response: We thank the commenters for drafting recommended language; however, because we have removed the alternative to total enclosures, these issues are no longer relevant.
   b. Ambient Monitoring Requirements
      Comment:  The EPA requested comments on the proposed alternative requirement of ambient monitoring, including whether two monitors would be sufficient or if more monitors may be necessary.  
      Commenter 98 stated that installing two monitors, with at least one located where highest air concentrations are expected, is not sufficient.  According to the commenter, the requirement "... should be strengthened to require continuous measurement from a sufficient number of monitors to capture both the dominant and intermittent wind patterns and regular verification and oversight by the permitting agency."  The commenter also suggested that a 30-day rolling average be adopted because a greater lag time exists before exceedances are identified and rectified using a three month rolling average. 
      Commenter 82 stated that two monitors would be sufficient, and offered the following support and suggestions: "Our historical air monitoring record and experience in the Pb emissions from these sources illustrates the significant influence of wind speed and direction on ambient air concentrations in the surrounding community.  Therefore, we believe the placement of at least one compliance monitor at the location of expected maximum concentration impact should be based on the most recent five years of meteorological data and approved regulatory modeling.  A second compliance monitor located at or near the plant boundary is necessary to observe impacts due to seasonal changes in meteorology.  This level of monitoring would be adequate for compliance demonstration provided the monitors were located according to the Probe and Monitoring Path Siting Criteria for Ambient Air Quality Appendix E to 40 CFR Part 58."
      Commenters 90, 96, and 91 recommended that the EPA follow the NAAQS siting requirements for ambient monitors in 40 CFR Part 58.  Commenter 91 noted that, when promulgating the Lead NAAQS siting criteria, the EPA rejected selecting sites solely based on the location of maximum estimated concentration.  Instead, the EPA considered the potential for population exposure and logistical considerations as factors to consider in siting decisions and changed paragraph 4.5 of 50 C.F.R. Part 58 accordingly.  The commenter further noted that the siting criteria in the proposed rule is not consistent with the NAAQS as it does not require the placement of monitors in "ambient air" locations, but requires siting "at or near the facility boundary..."
      Response:  We have removed the lead concentration in air monitoring alternative from this rule.  Therefore, the commenter's concerns related to the fenceline monitoring requirements need not be addressed in this rulemaking.
      Comment:  Commenter 90 noted that the EPA used the terminology "continuous monitoring system" in the proposed ambient monitoring requirements.  This monitoring system is not a continuous monitoring system and the specifications for CMS in §63.8(c) would not be appropriate.  
      Response:  We have removed the lead concentration in air monitoring alternative from this rule.  Therefore, the commenter's concerns related to the fenceline monitoring requirements need not be addressed in this rulemaking.
   c. Rule Clarifications
      Comment:  Two commenters (90, 96) requested a clarification that sources may switch between the two means of compliance.
      Response:  We have removed the option for facilities to monitor lead concentrations at the fenceline in lieu of totally enclosing fugitive generating processes. Therefore, this comment is no longer relevant.
      Comment:  Two commenters (90, 96) requested that the EPA clarify that its proposed alternative design standards do not preclude a regulated entity from offering alternative design standards.  According to the commenter, "EPA should include a provision... reaffirming regulated facilities' statutory right to seek approval of alternative measures that are equivalent to design standards and alternative design standards proposed by EPA."  The commenters also requested that the EPA clarify its alternative work practice equivalency requirements to provide clarity for sources that wish to exercise their statutory right under CAA 112(h)(3) to engage in equivalent alternative work practices.
      Response:  We note that the general provisions in 40 C.F.R. Part 63 Subpart A at §63.6(g) that apply to a request for approval of an alternative to a standard are specifically included in this rule as referenced in Table 1 to Subpart X. Facilities have the option to develop and submit an alternative set of fugitive emission control work practices to the Administrator for approval.  However, we note that it is the facilities' responsibility under these provisions to demonstrate to the Administrator that their proposed work practices are equivalent to those required in the final rule, and this would include being equivalent in terms of mass emission reductions.
      Comment:  Three commenters (90, 96, 94) stated that it would be inappropriate to consider the lead NAAQS as an emission standard because lead NAAQS values are affected by other sources and by background lead concentrations.  The commenters requested confirmation that monitored NAAQS exceedances would not constitute a violation of the CAA that could lead to civil or criminal liability under CAA §113.  Commenter 94 stated that it would not be appropriate to impose penalties for exceedances over 0.15 ug/m[3] since the monitored level is not isolated to emissions from the secondary lead smelter (and the ambient level is not an emissions standard)."  Commenter 96 noted that section 112(h) only allows for the EPA to promulgate a work practice, design, or equipment standard where "it is not feasible ... to prescribe or enforce an emission standard."  The commenter notes that "This provision would make no sense if design, equipment, or work practice standards were already "emission standards." 
      Response:  We have removed the lead concentration in air monitoring alternative from this rule. We are requiring total enclosures rather than providing the alternative for ambient monitoring. Since we are requiring total enclosures, differential pressure monitoring to demonstrate continuous compliance with the enclosure requirement, and work practice standards to prevent fugitive emissions, ambient monitoring at the fenceline is not necessary. Ambient monitoring data is already available from NAAQS monitors near secondary lead smelters. As noted in response at page 15 above, those data show that facilities with total enclosures and work practices like the ones being promulgated in this rule achieve ambient lead concentrations well below facilities that do not have such enclosures and well below the primary NAAQS for lead (a measure of unacceptable risk here).
      Comment:  Several commenters (82, 90, 96) requested that the EPA clarify what actions facilities must undertake in the case of an exceedance of the lead NAAQS.   Commenter 82 encourages the EPA to include a requirement to fully enclose process fugitive emission sources as corrective actions or, at a minimum, require the facility to submit a corrective action plan as part of a standard operating and maintenance procedure manual under the alternative compliance option.  Other commenters suggested that the EPA require sources to report the exceedances to the relevant permitting authority so that the permitting authority can determine what additional steps may be necessary.
      Response: We have removed the lead concentration in air monitoring alternative from the final rule.  Therefore, these concerns related to the fenceline monitoring requirements need not be addressed in this rulemaking.
Stack Emissions Limits
   a. Lead and Other Metal HAP
      Comment:  Commenters 90 and 96 argue that EPA has misapplied CAA section 112(d)(6) and should not be adopting any standards pursuant to that provision.  The argument is based on the term "necessary" in CAA section 112 (d)(6).  The argument goes that CAA section 112(d)(6) standards are not "necessary" here because they are unnecessary  to protect public health and the environment. 
      Response:  The EPA does not agree that determining whether standards under CAA section 112(d)(6) are "necessary" is determined exclusively by considerations of risk.    The "core requirement" of CAA section 112(d)(6) is the existence or non-existence of developments  in practices, processes, and control technologies, not a public health-based determination .  NRDC v. EPA, 529 F. 3d 1077, 1084 (D.C. Cir. 2008).  CAA section 112(d)(6)is also a continuation of the technology-based section 112 (d) standard-setting process, again indicating that the determination is not controlled exclusively by risk-based considerations.    Consequently the EPA does not believe that a CAA section 112 (d)(6) standard is "necessary" only if justifiable based on public health/risk considerations.   
      The EPA further notes that this is an argument without practical consequence here, because the EPA has found that standards are warranted to prevent unacceptable risk.  Moreover, there have been developments in control technologies (e.g. improvements in baghouse design and enclosure practices) which are available at reasonable cost and cost effectiveness.  .For example, all of the lead emissions data received after proposal reinforced our conclusion that the emissions limit proposed for lead stack emissions was warranted based on demonstrated levels of performance achieved in the industry. See Development of the RTR Emissions Dataset for the Secondary Lead Smelting Source Category for a description of the updated emissions estimates and see Cost Impacts for the Secondary Lead Smelting Source Category for a description of the cost and cost effectiveness of the revisions to the rule.   Consequently, EPA does not accept the commenter's argument that standards under section 112 (d)(6) are unnecessary and further does not believe that the argument has practical significance in this rulemaking given that the section 112 (d) (2) standards for this source category do not reduce public health risk to an acceptable level with an ample margin of safety.  
      Comment:  Commenter 90 stated that the EPA has provided no basis for proposing a lead stack concentration limit of 0.20 mg/dscm for all emission sources.  According to the commenter:
	
      EPA modeled stack and fugitive emissions of lead from facilities and compared the predicted results with the lead NAAQS.  EPA's conclusion was that lead concentrations exceeded the NAAQS and determined the risk was unacceptable.  EPA then remodeled facilities considering the reductions required by the RTR Proposed Rule.  The regulatory changes that affect emissions included reducing the stack lead concentration to 0.20 mg/dscm and reducing the fugitive emissions to account for work practices in the RTR proposed rule.  The results indicate that the facilities' predicted concentrations after implementing these changes were below the NAAQS; therefore, these changes are necessary under the residual risk review.

      The commenter first noted that there are facilities in this source category that currently comply with the NAAQS or are projected to comply in the near future without imposition of significantly reduced concentration limits for baghouses.  RSR's Middletown, NY facility currently complies with the NAAQS.  The Exide Technologies facility in Frisco, TX and the Texas Commission on Environmental Quality (TCEQ) developed an attainment demonstration for Collin County, Texas that does not require stack emissions to be reduced to 0.20 mg/dscm.  The commenter points out that at the Exide Frisco facility, in fact, the average flow-weighted concentration of lead from all modeled emission sources exceeds 0.20 mg/dscm and one source has emissions that exceed 1 mg/dscm.
      The commenter also stated that sensitivity analyses have not been conducted to determine the individual impacts of stack reductions and fugitive reductions, and that the reduction in fugitive emissions is likely sufficient to show predicted offsite lead concentrations below the NAAQS. The commenter stated that "although the impact of stack reductions on offsite sources is likely to be small relative to the contribution of fugitives, EPA artificially inflated the impact of stack emissions by running a modeling scenario at the allowable emission levels instead of the actual emission levels." The commenter requested that the EPA rerun the models using actual stack emissions to determine if fugitive emission reductions alone are sufficient to result in modeled lead concentrations below the NAAQS. The commenter also stated that in the cases that stack emissions are still determined to be relevant, the EPA should consider not only achievable reductions in emissions but also other methods that improve dispersion such as ensuring stacks are designed to minimize building downwash.
      Response:  As noted above, section 112 (f)(2) standards apply to an entire source category, but do not require every facility to pose unacceptable risk to trigger the section 112 (f)(2) standard requirement.  Just the opposite: the final sentence of section 112 (f)(2)(A) makes clear that  section 112 (f)(2) standards are triggered (for cancer risks) based on risks "to the individual most exposed to emissions from a source in the category" (emphasis added).  The standards then apply to all sources in the category or subcategory.  Moreover, the stack emission standards are performance based and do not require adoption of any particular control measure.  Thus, sources that already are emitting less than the specified level will not require further stack control.  The commenter initially notes that several facilities currently comply with the NAAQS or are projected to comply with the NAAQS in the near future whether or not EPA adopts standards for lead which are more stringent than those of the 1997 NESHAP, specifically citing RSR's Middletown, NY facility and Exide's Frisco, TX facility.  The commenter is correct that RSR's Middletown, NY facility currently reports ambient lead concentrations near the facility that are below the lead NAAQS.  However, as supported by the ICR responses available in the docket, RSR's stack emissions of lead are far below the facility-wide flow-weighted concentration limit of 0.20 mg/dscm presented in the proposed rule so this rule should not result in that source adopting further stack control for its lead compound emissions.  With regard to Exide's Frisco, TX facility, we note that the agreed order between Exide and the TCEQ in support of the SIP (available in the docket) requires Exide to replace two existing baghouses with new baghouses fitted with polytetrafluoroethylene (PTFE) membrane media and improved seating design, retrofit five other baghouses with new PTFE membrane media, and replace all the baghouse tube sheets with an improved seating design. The order also requires installation of secondary HEPA filtration on all baghouses that receive lead emissions with the exception of the furnace baghouses which are required to either install secondary HEPA filters or PTFE secondary filtration devices.  
      The commenter questions evaluating potential for risk based on allowable emissions.   EPA did provide risk estimates considering MACT allowable emissions from stacks, and it is permissible and reasonable to do so.  For carcinogens, in fact, EPA is require to assess whether "standards promulgated pursuant to subsection (d)"  pose a designated measure of risk to a most exposed individual, language which clearly can be read to apply to allowable emissions (i.e. emissions allowed by the standards  -  the subject of the review).  The statutory language for non-carcinogens is less specific but still readily amenable to consideration of allowable emissions (especially given no indication that Congress intended a different approach for carcinogens and non-carcinogens).  The EPA also assessed risk considering actual emissions from stacks.   Further, the EPA disagrees with the comment that reductions in fugitive emissions are likely sufficient to show predicted offsite lead concentrations below the lead primary NAAQS. Although this may be the case for most facilities in the source category, it is not the case for all.  As noted in the preamble, there was a facility that was estimated to have lead concentrations about three times the NAAQS for lead based on actual stack emissions only. See 76 FR 29052. Thus, for this facility, reductions beyond those in fugitive emissions would clearly be needed to achieve acceptable risk from lead emissions.  Moreover, we note that controls that result in reductions in lead emissions would also decrease the emissions of other HAP metals. As a result, at some facilities we would anticipate that these controls would also result in reduced cancer and acute risk from metals.  
      We have discussed the use of both allowable and actual emissions in previous actions, including 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 76603, December 21, 2006, respectively). In those previous actions, we noted that modeling the allowable levels of emissions (i.e., the highest emission levels that could be emitted while still complying with the NESHAP requirements) is inherently reasonable since they 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. 
      Comment:  Commenter 95 stated that the proposed standard for stack emissions of metal HAP does not satisfy the CAA's risk and technology review provisions.  The commenter stated that the EPA relied on practices and technologies that are out of date.  The commenter stated that "CAA Section 112(f)(2)(A)... states that if, upon completion of the eight year review, the existing MACT standards for a carcinogenic pollutant do not reduce lifetime cancer risks to less than 1-in-1 million, then EPA must promulgate standards under section 112(f) for sources emitting that pollutant".  The commenter argues that the EPA must revise the proposed standard for lead emissions to reduce maximum lifetime cancer risk due to metal HAP emissions to below 1-in-1 million.
      Response:  As an initial matter, we disagree that the technology review relied on practices and technologies that are out of date.  Section 112(d)(6) requires the EPA to evaluate developments in practices, processes, and control technologies.  Issues of cost and technical feasibility are legitimate consideration as part of determining whether standards are "necessary" under section 112 (d)(6). Our analysis indicated that there have been developments in fabric filtration that warrant a lower lead emission standard for this source category.  The stack emissions limit for lead adopted in this final rule will achieve an estimated 8.2 tons per year of metal HAP reductions at an annualized cost of $2.7 million dollars ($0.33 million dollars per ton of HAP reduced). This limit is based on the performance of a well-operated baghouse.  Baghouses meeting this limit sometimes employ HEPA filters as a polishing measure after the primary filter. However, HEPA filters are not always feasible or necessary. These polishing filters are amenable to control of particulate from building ventilation sources that do not have extremely high temperatures or particle loading. While the lead concentrations from stacks equipped with HEPA filters were on average about 20% lower than those without, the existence of the HEPA filter was not the lone variable influencing the difference in concentration.  Other factors such as age of the primary control device, type of baghouse used, and type of process vented to the emission point likely contributed significantly to the distribution of lead concentrations from the stacks. Additionally, HEPA filters are only applicable to some sources where high exhaust temperature or high particulate loading will not interfere with the proper operation of the filter. Because of these reasons, we did not believe the dataset warranted establishing an emissions standard lower than 0.20 mg/dscm based on the use of a HEPA filter. See Summary of the Technology Review for the Secondary Lead Smelting Source Category, available in the docket.
      To achieve significant reductions beyond those possible using a well operated baghouse, we evaluated an additional polishing control device, a wet electrostatic precipitator. This technology could achieve metal HAP reductions of about 19.2 tons per year (i.e. an additional 11 tons of metal HAP), however the cost (annualized cost of $46 million dollars, $2.4 million dollars per ton of HAP reduced) would be over 15 times higher than the costs of using a well-operated baghouse. The use of a wet electrostatic precipitator would also increase electricity demand, increased emissions associated with electricity generation (with attendant carbon and NOx pollution), and additional wastewater generation.  These significantly increased costs, poor cost effectiveness, and collateral adverse energy and environmental impacts  support EPA's decision not to require further reductions under section 112 (d)(6).
       The commenter is mistaken that section 112 (f)(2) requires EPA  to reduce maximum lifetime cancer risk to below 1-in-1 million, and the D.C. Circuit has in fact rejected the commenter's argument.  Moreover, as stated in the Benzene NESHAP, in determining the need for residual risk standards, we strive to limit to no higher than approximately 1-in-10 thousand (100 in a million) the estimated cancer risk that a person living near a plant would have if he or she were exposed to the maximum pollutant concentration for 70 years and, in the ample margin  of safety decision, to protect the greatest number of persons possible to an individual lifetime risk level of no higher than approximately 1-in-1 million.  As noted in the proposal preamble, even the highest estimated cancer risk from actual emissions from this source category of 50-in-1 million is below the 100-in-1 million threshold identified in the benzene NESHAP.  See 76 FR at 29052, Table 3. We therefore determined that the inhalation risk due to actual emissions from this source category was acceptable.  See 76 FR at 29055/1.  We determined that the overall risk due to allowable emissions was, however, unacceptable, and we proposed a revised standard that would reduce the MIR due to allowable emissions to acceptable levels.  The proposed standard also reduced the MIR due to actual emissions from 50-in-1 million to 10-in-1 million.  Since the MIR estimated after the proposed controls for metal HAP emissions was above 1-in-1 million, we evaluated the need for additional controls to provide an ample margin of safety for public health taking into account cost and feasibility. See 76 FR at 29057. However, we did not identify any further feasible and cost-effective controls, and we therefore concluded that the revisions proposed under section 112(f)(2) will provide an ample margin of safety with regard to lead emissions from this source category. We remodeled the source category after the proposal to incorporate public comments regarding emissions, boundary and other information relevant to performing a risk assessment. The results estimate the same baseline inhalation cancer risks based on actual emissions (50 in a million) although the MIR facility has changed. Post-control we now estimate that MIR to be 7 in a million (i.e. slightly less than estimated risk at proposal). See EPA-HQ-OAR-2011-0344-0036 at page 36, stating the post-control cancer MIR was 10 in based on the proposal risk assessment and see Residual Risk Assessment for the Secondary Lead Smelting Source Category, which is available in EPA-HQ-OAR-2011-0344 at page 35 for the post-control risk results for the final rule. Moreover, we note that the baseline MIR due to allowable emissions remains 200 in a million and will be reduced to acceptable levels after controls. We performed an ample margin of safety analysis to determine whether additional controls are warranted considering cost and technical feasibility. We have determined that the controls required in this final rule include all of the controls that are technically and economically feasible to reduce cancer risks from fugitive emissions. This analysis resulted in some specific work practices which we proposed not being required in the final rule (e.g. roof washing). However, total enclosures are a requirement in the final rule rather than an option. This requirement, coupled with the work practices prescribed in the final rule, will prevent fugitive emissions from being generated outside of total enclosures or entrained inside enclosures and carried out. These requirements will protect the public health with an ample margin of safety.  
      Comment:  Commenters 95 and 98 disagreed with the EPA's analysis regarding the WESP.  Commenter 95 stated that the EPA overstated the cost of the WESP and that the EPA should revisit the MACT floor for this industry to account for this new technology that has resulted in the RSR Corporation far out-performing every other company and facility.  Commenter 95 stated that RSR submitted cost data showing that costs are between $18 and $20 million, or a total cost to the industry of $234 to $260 million. Commenter 95 stated that the WESP cost (per ton of lead) represents 0.4 percent of the value of one ton of lead.  Commenter 98 stated that the fact that three facilities in this source category are able to install the technology shows that reductions from the technology are achievable, taking into account cost.  Commenter 98 noted that the Clean Air Act is a technology-forcing statute, not one meant to enshrine the practices already achieved by all or the vast majority of the industry.  Commenter 98 further stated that the EPA fails to provide a rational justification for not requiring emissions reductions based on the WESP technology.  The commenter notes that the non-cancer HQ that the EPA found is five times the level associated with public health concerns and that the fact that costs are "high" is not sufficient reason for the EPA not to consider how much acute or cancer risk reduction would occur if the EPA were to require further emissions reductions based on the WESP.
      Commenter 95 also stated that the WESP is a polishing unit and the EPA appears to have compared the WESP with industries where WESPs are used as primary controls.  The commenter stated that the EPA also appears to believe that RSR uses the WESP unit to treat fugitive emissions. 
      Response:  First, whether or not section 112 (d)(6) is "technology forcing", the EPA retains very significant discretion in balancing relevant factors in determining whether it is "necessary" to revise the existing technology-based MACT standards.  Sierra Club v. EPA, 325 F. 3d 374, 378 (D.C. Cir. 2003). In reviewing section 112 (d) (2) standards, and determining whether to revise them is "necessary" under section 112 (d)(6), the EPA may take into consideration cost and feasibility when evaluating developments in practices, processes, and control technologies.  Indeed, it is reasonable that any such "review" consider the same factors which EPA is required to consider under section 112 (d)(2)  -  cost, non-air environmental impacts, potential impacts on energy usage among them.  The EPA determined that requiring installation of the WESP at all facilities would result in a total capital cost to the industry of approximately $400 million.  See Cost Impacts for the Secondary Lead Smelting Source Category, at page 5, available in the docket (Docket ID: EPA-HQ-OAR-2011-0344-0040). Given the amount of emissions reductions that would occur with installation of the WESP, and given that the impact of stack emissions on risk is low relative to fugitive emissions and that the emission limits in the final rule will obtain substantial reductions in HAP emissions, the EPA determined that the WESP is not a cost-effective control option and is not warranted under section 112(d)(6) or 112(f)(2). Specifically, an emissions limit based on this technology would result in annualized cost to the industry of about $46 million dollars per year with a cost effectiveness of about $2.4 million dollars per ton of HAP reduced. As noted in a previous response, this is roughly 20 times greater than the control based on performance of state-of-the-art baghouses without the following step of a WESP. We have determined that the limits included in the final rule will provide an ample margin of safety, and the additional cost to meet a limit based on WESP technology is not warranted under either statutory provision. As noted above, the energy use associated with operation of a WESP also has negative environmental implications and is another factor in EPA's decision not to adopt standards predicated on use of this technology.
      Commenter 95 asserted that RSR submitted cost data showing that total cost to the industry of installing WESPs is between $234 and $260 million rather than  $400 million as estimated by EPA at proposal. The EPA did consider the data submitted by RSR in estimating the potential cost to the industry of installing WESPs.  However, it would not be appropriate to simply assign the $18 to $20 million cost incurred by the RSR facility to each of the additional facilities, as the facilities differ significantly in several aspects (e.g., number of emission points, furnace types, furnace stack flow rates, process fugitive enclosure hood flow rates, etc).  Instead, the EPA scaled the costs submitted by RSR for each individual facility based on the reported flow-rates of each emissions point. For example, the costs incurred would be influenced by the size of a facility and the distance between existing control devices. The Quemetco CA facility covers a much smaller area than many of the facilities and the costs for ducting existing control devices into a polishing WESP could be substantially higher for larger facilities. We further note that the EPA assumed that, at each facility, the WESP would treat both process and process fugitive emissions (those emissions that are controlled via baghouses rather than those controlled via cartridge collectors), consistent with information submitted by RSR.  Commenter 95 is therefore incorrect in their statement that the EPA believes that RSR uses the WESP unit to treat fugitive emissions (i.e., building ventilation systems). The EPA believes the cost estimate developed for installation of a WESP at other secondary leads smelting facilities is a reasonable estimate.  Furthermore, the commenter provided no facility-specific cost estimates to demonstrate that the EPA's estimates are not reasonable. See response at page 90 for discussion of the proposal post-control acute hazard index of 5.
      Comment:  Commenter 95 stated that the EPA should have relied on SCAQMD rule 1420.1 as a basis for adopting alternative standards and requirements for stack emissions of metal HAP.  The commenter argued that SCAQMD rule 1420.1 covers the secondary lead smelting facility with the best control (Quemetco, CA) as well as one identified by EPA as most likely to flirt with non-compliance (Exide Technologies, CA).  The commenter stated that the SCAQMD rule is based on an "up-to-date and robust technical basis reflecting SCAQMD staff analyses..."
      Response:  We are familiar with SCAQMD 1420.1, and did in fact take many aspects of that rule into consideration when developing the revised NESHAP for this source category.  However, we believe first that all of the SCAQMD 1420.1 standards are not necessary to reduce risk to an acceptable level under section 112 (f)(2) and that further controls are not needed to provide an ample margin of safety, and also believe that the full panoply of control under the SCAQMD rule is not necessary as part of further technology-based standards under section 112 (d)(6).  Thus, it is neither necessary nor appropriate to uncritically apply to an entire source category the standards developed by SCAQMD for two facilities in a unique geographic area with particularly unusual  meteorological characteristics.  The commenter cites the total facility mass lead emission rate of 0.045 pounds per hour and the maximum lead emission rate of 0.01 pounds per hour specified in SCAQMD 1420.1.  The commenters claim that "SCAQMD's decision to adopt the new Rule 1420.1 and the more rigorous standards it contains was driven by the need to meet the NAAQS as revised in 2008..."  We acknowledge that SCAQMD's analysis may have determined that the aforementioned emissions limits may be necessary in order for the Exide Technologies and Quemetco, Inc. facilities located in southern California to meet the revised lead NAAQS.  However, our analysis indicates that unacceptable risk from lead emissions can be eliminated, with an ample margin of safety, by adopting the controls in this final rule. See The Residual Risk Assessment for the Secondary Lead Smelting Source Category, available in the docket. The lowered stack emission limit will ensure that unacceptable risk from stacks is eliminated and we have finalized requirements to significantly reduce fugitive emissions (the dominant contributor to risk from this source category) from secondary lead smelters through the implementation of fugitive emission work practices, many of which are included in SCAQMD 1420.1, and through requiring all secondary lead sources to install total enclosures maintained under negative pressure and vented to a control device for all lead-bearing materials. 
      Comment:  Commenter 98 argued that any standard set under section 112(d), including those set under section 112(d)(6), must meet the requirements of section 112(d)(2) requiring standards to reflect the maximum achievable degree of emission reduction.  By this logic, the commenter stated that the EPA has no justification for failing to recalculate the MACT floor for lead based on new technologies.  The commenter stated that the EPA therefore must set the standard for existing sources at the average emission level achieved by the best performing 5 sources, and at the level achieved by the best controlled similar source for new sources.
      The commenter stated that the EPA cannot rely on the HON case to evade its duty to satisfy section 112(d)(6).  According to the commenter,

      EPA is right that the HON decision stated that it did "not think the words `review, and revise as necessary'" required EPA to recalculate the floors "from scratch" in that case.  NRDC v. EPA, 529 F.3d at 1084.  The court explained that there was no need to address whether EPA had satisfied section 112(d)(6), and that "we do not have to decide this questions because in its final rule, EPA squarely found that there were no significant developments in practices, processes and control technologies, and petitioners do not challenge this conclusion."
      
      As noted, there are such "developments" for this source category.  Therefore, EPA cannot rely on the HON case to evade its duty to satisfy section 112(d)(6).  Even under NRDC  -  assuming arguendo that its section 112(d)(6) holding is in any way relevant here  -  section 112(d)(6) requires EPA to recalculate the MACT floor when there have been advances in technology, practices, and processes, and when there is information showing that greater emission reductions have been "actually achieved."  Commenter contend that, based on the information EPA has, it is therefore "necessary" for EPA to strengthen the existing MACT floor to ensure it now complies with section 112(d)(2)-(3).

      The commenter further argues that since the EPA must set new MACT floors based on developments in technologies, practices, and processes, it may not consider cost in setting the new MACT standard for lead.
      Response:  First, EPA determined long ago that section 112 (d)(6) does not require MACT floors to be recalculated, and why EPA's interpretation that no further floor analysis is required was reasonable.  See 70 FR at 20008 (April 15, 2005). EPA is not reopening that issue here, or otherwise reconsidering its interpretation.  Thus, this comment is considerably out of time.  Moreover, the argument was rejected by the D.C. Circuit in the HON opinion.  See 529 F. 3d at 1084 ("It is argued that EPA was obliged to completely recalculate the maximum achievable control technology-in other words, to start from scratch. We do not think the words "review, and revise as necessary" can be construed reasonably as imposing any such obligation.").  We thus disagree with the assertion that the HON Court's ruling that CAA section 112(d)(6) does not require re-calculation of MACT floors was limited to instances in which there have not been developments in practices, processes, or control technologies. In fact, the Court was quite clear on this point, and declined to rule only on whether it was appropriate for the EPA to consider costs and risks in conducting CAA section 112(d)(6) reviews, as the issue was rendered moot by the litigants' failure to preserve it. 
      To the extent that the commenter is arguing more generally that section 112 (d)(2) is technology-forcing and therefore dictates that EPA must revise MACT standards to reflect new technological developments, see responses on pages 30 above.
      Comment:  Commenter 98 stated that the proposed standard for lead and other metal HAPs pursuant to the technology review is arbitrary and capricious for three reasons.  First, the EPA fails to discuss controls required by the South Coast Air Quality Management District (SCAQMD) and compare them to its proposed rule.  The commenter argues that such an omission violates the EPA's requirements under section 112(d)(6).  Second, the EPA provides no explanation for not considering reductions achievable by the use of HEPA filters downstream of baghouses.  The commenter stated that the DHEQ permit for Johnson Controls mandates use of HEPA filters which demonstrates their feasibility.  Third, the commenter argues that the EPA does not provide a rationale for proposing a standard at a level where almost all facilities have achieved it, rather than set at a lower level of pollution that is "achievable".  The commenter stated that "Implicitly, EPA suggests that it chose the proposed standard because it happened to match the proposed standard it developed under the residual risk analysis."
      The commenters contend that "EPA's proffered justifications show that the proposed standard is arbitrary and capricious.  They fail to comport with the technology-forcing aspect of the Act and of the MACT.  They render the standard a mostly empty formality since almost all facilities and stacks are already meeting the standards."
      Response:  As noted above, we did evaluate the controls required in SCAQMD 1420.1.  For example, we evaluated a significantly lower lead emissions limit based on the WESP technology implemented at the Quemetco facility in City of Industry, California. See 76 FR 29058 and pages 29-31 above. We also evaluated and ultimately proposed to require total enclosures for the same process and process fugitive emissions sources listed in SCAQMD 1420.1. See 76 FR at 29072. Furthermore, several of our proposed fugitive emission work practices, though not identical to, are very similar in nature to those listed in SCAQMD 1420.1.  We have explained at pages 29-31 above why further stack controls on lead emissions are not necessary under section 112 (d)(6), and why further controls on fugitive emissions (beyond those based on total enclosure of all lead-based materials) is also not necessary.  With regard to HEPA filters, the EPA did consider whether significant reductions in emissions were demonstrated by use of this technology and determined that the most significant factors influencing reduced lead emissions in this industry were not the use of HEPA filters.  See Summary of the Technology Review for the Secondary Lead Smelting Source Category, at page 5.   We did not believe that the data warranted an emissions standard based on the technology.  While the lead concentrations from stacks equipped with HEPA filters were about 20% lower than those without, the existence of the HEPA filter was not the lone variable influencing the difference in concentration.  Other factors such as age of the primary control device, type of process vented to the emission point, and flow rates likely contributed significantly to the distribution of lead concentrations from the stacks. Additionally, HEPA filters are only applicable to some sources where high exhaust temperature or high particulate loading will not interfere with the proper operation of the filter. Because of these reasons, we did not believe the dataset warranted establishing an emissions standard lower than 0.20 mg/dscm based on the use of a HEPA filter. See Summary of the Technology Review for the Secondary Lead Smelting Source Category, available in the docket.
      We disagree with the commenter that the EPA failed to provide a rationale for the lead emissions standard proposed under section 112(d)(6).  Section 112(d)(6) requires the EPA, in reviewing section 112 (d)(2) standards and determining whether it is necessary to revise them, to evaluate developments in practices, processes, and control technologies.  The data presented in the technical document describing the technology review for this source category clearly demonstrates that advances in fabric filtration have allowed sources in this industry to achieve lead emissions far below the limits established in the 1997 NESHAP. The data collected from industry in ICR responses demonstrated that the average lead concentration in stacks was 0.16 mg/dscm, far below the 2.0 mg/dscm level prescribed in the 1997 NESHAP. See Summary of the Technology Review for the Secondary Lead Smelting Source Category, at page 7, available in the docket. To that end, we have proposed to revise the lead emission standard for this source category to reflect those developments.  The proposed lead emissions standard was not chosen because "most stacks are meeting the standards already", but rather because we determined it to represent a lead concentration achievable by well-performing fabric filters.   Important factors that influenced the outlet concentration achieved by fabric filters were the type of baghouse used (pulse-jet and reverse-air baghouses achieved lower concentrations than shaker baghouses) and the age of the baghouse. Older baghouses had substantially higher outlet concentrations. Possible reasons for the improved performance in newer baghouses include improvements in bag design, improved seating to ensure proper sealing between bags, and more efficient bag cleaning mechanisms.  We further note that we did evaluate an emissions limit based on the WESP used following a fabric filter, another development in practices, processes, and control technologies identified in our review.  However, we determined that the WESP was not a cost-effective control option for this source category The estimated costs that would be incurred to install this technology at all of the facilities in the industry would be roughly $400 million dollars in capital investment with about $46 million dollars of total annualized cost. The cost effectiveness of this option was unacceptably high, given the incremental risk reductions that would be achieved based on this technology. Adverse energy implications of use of a WESP also militate against adopting standards predicated on use of the technology.  Finally, the lead emissions standards under section 112(f)(2) did not, and do not dictate the standards under section 112(d)(6).  The final standards satisfy the requirements of both sections, the analyses under these respective sections are independent of each other.  We further note that the ample margin of safety analysis under section 112 (f)(2) is internally consistent with our determinations under section 112 (d)(6) in that we did not find that further controls were justified based on considerations of cost, cost effectiveness, technical feasibility, and energy use implications.
      Comment:  Commenter 98 stated that in setting the emission standard for lead, the EPA inadequately supported its findings that there are no other less expensive or feasible control options.  The commenter notes that the EPA identified in its own analysis that other facilities are using HEPA filters in addition to baghouses to achieve approximately 20 percent lower outlet lead concentrations than baghouses alone.  The commenter also notes that the DHEQ permit for Johnson Controls mandates construction of HEPA filters with baghouses, demonstrating the viability of their use.
      Response:  While the lead concentrations from stacks equipped with HEPA filters were on average lower than those without HEPA filters, the dataset did not show a large difference in lead concentrations between the emission points.  Outlet concentrations for stacks equipped with fabric filters averaged about 0.14 mg/dscm while stacks equipped with a HEPA filter following a fabric filter averaged about 0.11 mg/dscm. Fabric filters used in pulse-jet baghouses averaged well below 0.10 mg/dscm. See Summary of the Technology Review for the Secondary Lead Smelting Source Category, which is available in docket ID EPA-HQ-OAR-2011-0344 at page 5. The key indicator of performance does not appear to be whether a HEPA filter is used, rather it is what type of baghouse is used and the age of the baghouse, as illustrated by the performance of stacks equipped with pulse-jet baghouses. Furthermore, other factors such as age of the primary control device, type of process vented to the emission point, and type of baghouse likely contributed significantly to the distribution of lead concentrations from the stacks. Additionally, the use of HEPA filters can be difficult for stacks with high particle loading and exhaust gas temperature.  Since the use of a properly designed, well operated baghouse can achieve outlet concentrations that provide an ample margin of safety and do not present the potential technical challenges that can hamper performance of HEPA filters, we do not believe the establishing an emissions standard based on the use of a HEPA filter is warranted.
      Comment:  According to commenter 91:
EPA proposes "a facility-wide, flow-weighted average lead concentration limit of 0.20 mg/dscm to cover all stacks in this source category." 76 FR at 29055-56.  This limit is based on a finding that the allowable emission rate at two facilities was approximately 10 times the Lead NAAQS level, with that finding adjusted downward by 90% to set the proposed limit.  Shell Consulting Report at 4.
      
      The commenter stated that the EPA used fewer than 5 facilities and allowable, not actual emissions to set the limit.  According to the commenter, this raises questions as to whether the limit complies with statutory directions and also whether it reflects conditions that are representative of those two facilities, rather than the industry as a whole.  The commenter notes that, for example, the approach taken by the EPA in setting the limit "fails to recognize that a number of facilities in the category emit from very tall stacks (e.g., Buick's 200 foot stack) that disperse the plume over a much larger area, and thus have relatively low ground level concentration at the unit."
      Response:  The EPA is adopting a flow-weighted average lead concentration limit of 0.20 mg/dscm under the authority of section 112(f)(2) and separately under the authority of section 112(d)(6).
      The limit being promulgated under section 112(f)(2) ensures that the risk due to allowable stack emissions from this source category is acceptable.  We have discussed the use of both allowable and actual emissions in previous actions, including 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 76603, December 21, 2006, respectively). In those previous actions, we noted that modeling the allowable levels of emissions (i.e., the highest emission levels that could be emitted while still complying with the NESHAP requirements) is inherently reasonable since they reflect the maximum level sources could emit and still comply with national emission standards.  We further note that standards set under section 112(f)(2) are not MACT floors and are therefore are not developed using  the MACT floor setting procedures (i.e., consideration of the five best performing facilities) of section 112(d)(2) and (3).
      The limit being promulgated under section 112(d)(6) was a result of the technology review conducted for this source category.  As described in the preamble, we determined that the main development in practices, processes, and control technologies for this source category was for fabric filtration.  We also identified an additional control technology (i.e., a WESP), but determined that it was not cost effective, 76 FR at 29059-60, and has negative energy implications.  We also noted that in conducting the section 112(d)(6) reviews, the EPA is not obliged to completely recalculate the prior MACT determination, and, in particular, is not obligated to recalculate the MACT floors. NRDC v. EPA, 529 F.3d 1077, 1084 (D. C. Cir., 2008).  The commenter expressed concern that the proposed limit may reflect the conditions of the two facilities, rather than the industry as a whole.  We disagree with this assessment since 74 of the 93 stacks identified in the ICR that are controlled using a baghouse reported average lead concentrations of less than 0.20 mg/dscm.
      Comment:  Commenter 95 recommended that the EPA revise the proposed rule to include emission standards for lead and other HAP that reflect the best control technologies currently utilized by the industry, and limit emissions to nine pounds of lead per year from process stacks.  The commenter also recommends a facility-wide stack emissions limit of 25 pounds per year of lead.
      The commenter stated that the proposed flow-weighted standard for lead will not result in mass reductions of lead and other HAPs.  The commenter contends that instead of installing additional air pollution controls or procedures to achieve compliance, facilities will simply direct air flow through "cleaner" process vents that would offset higher concentrations from "dirtier" process vents.
      Response:  The emission standard for lead in the final rule reflects our assessment of the developments in practices, processes, and control technologies for this industry.  Based on our review, advances in fabric filtration have made it feasible for sources in this industry to achieve stack lead concentrations less than 0.20 mg/dscm.  We did identify one add-on control technology with the ability to reduce lead concentrations substantially beyond the levels achieved by a well-maintained fabric filter (i.e., the WESP).  However, we note that our technology review under section 112(d)(6) includes an analysis of the technical feasibility of applying the identified developments in practices, processes, and control technologies, as well as the estimated impacts of applying these developments, including cost.  Based on these considerations, we determine whether it is necessary to amend the regulation to require any of the identified developments.  As discussed in Summary of the Technology Review for the Secondary Lead Smelting Source Category, we determined that the WESP is not a cost-effective control technology, and has negative energy implications, and that it would therefore not be appropriate to revise the lead emission standard based on use of this technology.  
      We believe that it is highly unlikely that facilities will simply direct additional air flow through the "cleaner" process vents in order to offset higher concentrations from the "dirtier" process vents because rerouting these processes and modifying the control devices could require significant investments. Additionally, facilities would be required to modify their Title V permits, it is unlikely that their permitting agencies would allow for such modifications when the intention would clearly be to flout the intention of an emission standard. 
      Comment:  Commenter 98 noted that the vast majority of stacks are already meeting the proposed emission standard for lead.  The commenter also notes that even the average lead emissions from all sources, which distorts the representation of what most facilities are achieving, stands below the proposed emission standard.  The commenter contends that the data demonstrate that the emission standard can be lowered, taking feasibility and cost into account.
      Response:  The emission standard for lead represents a level that we determined is achievable by a well-performing fabric filter, which is the main technology we identified that is currently used by this industry (although, as noted, not all fabric filters perform equally; the revised standard is predicated on use of the best fabric filters coupled with a rigorous maintenance schedule). We evaluated proposing a lower emission standard based on the WESP technology, but determined that it was not appropriate when considering cost.  Therefore, a flow-weighted average lead concentration limit of 0.20 mg/dscm is appropriate for this source category since it represents a level achievable by the best-performing version of the control technology implemented by this industry (i.e., a new, well operated and maintained baghouse).
      Comment:  Commenter 98 stated that the data support a lower standard for lead for fugitive emissions that are vented to a stack from the required total enclosure.
      
      Response:  We agree that the average lead concentration in stacks that only contain vents from buildings is lower than the process vent stacks.  These vents are expected to have lower lead concentrations because the inlet lead concentration is far lower from building sources than from process sources.  Furthermore, our analysis indicates that building vents are the sources most amenable to the addition of HEPA filtration.  The EPA considered establishing sub-categories for the lead emission standard.  However, there are several different types of vents that would need to be considered.  Furthermore, each facility combines these process vents in different ways, limiting the information available from any individual source type.   Therefore, we adopted a flow weighted average limit that takes into account all types of sources, adding compliance flexibility for the same emission reductions, and making it unnecessary to adopt a separate emission standard for each type of vent.
      
      Comment:  Two commenters (90, 93) agreed with the EPA's conclusions with respect to the evaluation of the WESP technology.
      Response:  We acknowledge the commenters' support.
      Comment:  Two commenters (92, 80) supported the EPA's facility-wide flow weighted emissions limit for lead.
      Response:  We acknowledge the commenters' support.
   a. Total Hydrocarbons (THC) and Dioxins and Furans (D/F)
      Comment:  Commenter 92 fully supports the work practice requirement to separate plastics entering the furnace.  The commenter suggested including a procedure to correlate the approximate plastic separation with the stack test results for organic HAP and dioxin and furans.  The chromium electroplating NESHAP was given as an example regulation that tied an operating parameter to performance testing.
      Response:  We note that we have modified the proposed plastics separation requirement to apply to automotive batteries. We agree with the commenter that it can be useful to tie performance testing results to an operating parameter that can be continuously monitored. That is why we have included exhaust temperature monitoring to demonstrate continuous compliance with the standards for THC and dioxins. While plastics are a source of organic HAP in furnace exhaust, they are not the only source. Therefore, we feel that temperature monitoring is the appropriate measure for demonstrating continuous compliance rather than measurement of plastics separation effectiveness.
      
      Comment:  Commenters 90 and 96 requested that the EPA clarify proposed 40 C.F.R. § 63.547(e)(2) by including a specific reference to the 2005 Toxic Equivalency Factors (TEF) from the World Health Organization (WHO).
      
      Response:  We have made the commenters' suggested revision to the regulatory text.
      
      Comment:  Commenter 80 recommended that the EPA set the dioxin and furan MACT floor for existing blast furnaces based on the data from the mixed sources (blast furnace off-gas mixed with reverberatory furnace off-gas).
      Response:  We did consider assigning all of the D/F emissions from tests at facilities where the vents from blast furnaces are mixed with the vents from reverberatory furnaces after the streams are cooled (where the reverberatory furnace is not controlling emissions from the blast furnace) to the blast furnace in order to calculate MACT floors for the blast furnace subcategory.  However, unlike the case of the stack emission standard for lead (where one limit exists regardless of furnace type), we did not have information regarding the individual flow rate from each furnace during the emission tests (which was necessary to incorporate these data into the pool of data used to calculate the MACT floor), and were therefore unable to assess the relative contribution of each furnace type.   
      Comment:  Commenter 93 stated that numeric D/F standards for this industry represent a cost burden disproportionate with any perceived benefit.  The commenter notes that Method 23, the reference method for D/F emission testing, specifies a very complex sampling train, long sample times, and intricate sample recovery and analytical procedures.  The commenter stated that a typical D/F test program will cost an affected facility between $15,000 and $20,000 per test program to complete and will require the emission test team to be on-site for over three days.  The commenter contends that the EPA should reconsider the imposition of numeric D/F standards on affected Subpart X sources.
      Response:  First, EPA is legally obligated to promulgate section 112 (d)(2) standards for listed HAP emitted by a major source category.  National Lime, 233 F. 3d at 634.  It is not disputed that secondary lead sources emit CDD/CDFs.  Second, this standard must be numeric unless the criteria for establishing work practices under section 112 (h) are satisfied.  No commenter attempted such a justification for CDDs, and EPA is not aware of any.  In addition, no commenter suggested a legitimate surrogate for CDDs which could be tested at less expense.  Consequently, EPA believes that some type of numeric standard for CDD/CDF is legally required. 
      Comment:  Commenter 94 and 96 noted that the EPA has proposed to change the definition of collocated blast furnace and reverberatory furnace by removing from the subcategory those blast and reverberatory furnaces whose gases are not mixed prior to cooling.
      The commenters noted that ABR and the EPA worked collaboratively to identify a subset of industry stacks across facilities for emission testing intended to inform this rulemaking.  The commenters contend that the EPA did not indicate in this information collection process that the Agency was considering redefining the collocated blast and reverberatory furnace subcategory.  As a result of this change in approach unanticipated by the commenter, only one collocated blast and reverberatory furnace was tested, the result being that the EPA's proposed dioxin and furan emission limits for this subcategory of five collocated blast and reverb furnace pairs were based solely on emissions test data from a single facility.
      Commenter 94 stated that establishing a dioxin and furan limit for collocated blast and reverberatory furnaces based on a single unit is improper because it "do[es] not represent the average achieved by the best-performing sources in the subcategory.".  The commenter also notes that Exide advised the EPA on June 15, 2011 that it is in the process of coordinating stack testing on a collocated blast and reverberatory furnace at its Reading, Pennsylvania facility; Exide expects the data to be available in September, 2011.  The commenter contends that the EPA should ensure that it allows for adequate time to accept and consider the pending test data from Reading in determining the dioxin TEQ limit for collocated blast and reverberatory furnaces.
      Response:  We believe that our proposed change to the definition of collocated blast and reverberatory furnace is appropriate.  We maintain that designating a blast furnace and reverberatory furnace as "collocated" should imply that the much hotter off-gas of the reverberatory furnace is providing some level of control for the organic HAP in the relatively cooler blast furnace off-gas.  In order for this to occur, the off-gas from the reverberatory furnace should be mixed with the blast furnace off-gas prior to cooling. Section 112 (d)(3) determinations are to reflect sources "for which the Administrator has emissions information" which in this case is the East Penn facility. The data from additional testing at Exide's Reading facility was not provided to the EPA until November 17, 2011. The data were submitted too late for the proper quality assurance analyses to be performed prior to being incorporated into the MACT floor calculation. However, we note that a preliminary analysis indicates that the limit would have been slightly more stringent if these data were incorporated. See Summary of MACT Floor Analysis for the Secondary Lead Smelting Source Category. The data from the East Penn facility remains the data on which the limit is based. The commenter did not provide any data showing that the proposed limits were infeasible or unrepresentative of performance at the East Penn facility; furthermore, the test data provided by Exide in November 2011 only reinforce that this limit is representative of performance of furnaces in this subcategory.  	
      Comment:  Commenter 90 requested confirmation that reverberatory furnaces that are collocated with blast furnaces are only subject to the proposed standards for collocated blast and reverberatory furnaces even at times when the facility's blast furnace is not operating.
      Response:  The commenter is correct that reverberatory furnaces that are collocated with blast furnaces are subject to the standards for collocated reverberatory and blast furnaces even at times when the facility's blast furnace is not operating. When the blast furnace is not operating, the emissions should be less than the combined emissions from the mixed exhaust produced with both furnaces operate. The reverberatory furnace will thus operate well within the limit for collocated furnaces when the blast furnace is not operating.
      Comment:  Commenter 95 expressed support for the EPA's proposal to establish emission standards for organic HAP and dioxins for reverberatory and rotary furnaces.  The commenter believes that the EPA is exercising a mandatory duty in addressing these emissions.
      Response:  We acknowledge the support.
      Comment:  Commenter 98 stated that the EPA failed to give a reasoned explanation for not proposing a stronger standard for dioxins and furans, to provide an ample margin of safety for public health.  The commenter notes that the EPA identified a control that could lead to greater risk reduction  -  the installation of additional afterburner capacity.  The commenter stated that the EPA did not calculate the cancer risk reduction that would occur if the EPA required these emissions reductions.  Instead, it relied on the Benzene Rule's 100-in-1 million presumption to conclude that emissions reductions would reduce cancer risk to a level that is "clearly less than" that benchmark.  The commenter contends that section 112(f)(2) requires the EPA to consider additional reductions to provide an "ample margin," not just the bare minimum amount of protection for public health.  The commenter further stated that the potential for increased emissions of NOx and CO2 is not a relevant factor or valid justification for not requiring HAP reductions under § 112.
      Response:  The EPA believes it is appropriate to maintain the benzene NESHAP decision framework for determining risk acceptability.  See section 112 (f)(2) (B) adopting that decision framework into the section 112 (f) decision process.   Under the Benzene NESHAP we strive to limit to no higher than approximately 1-in-10 thousand (100 in a million) the estimated cancer risk that a person living near a plant would have if he or she were exposed to the maximum pollutant concentration for 70 years and, in the ample margin of safety decision, to protect the greatest number of persons possible to an individual lifetime risk level of no higher than approximately 1-in-1 million taking into account cost, feasibility of controls, and non-air impacts.  In this regard, EPA certainly may consider if there are collateral environmental impacts of controls, including increased emissions of other air pollutants, or energy implications and attendant emissions of CO2 air pollution.  These are, in fact, among the "other relevant factors" which EPA may consider.  See section 112 (f)(2)(A).  (Indeed, the commenter's construction would lead to the anomaly that further controls could lead to adverse health or environmental impacts which EPA would have to disregard  -  this when implementing a provision whose ultimate purpose is to protect against such risks.)  
      Results of the multipathway risk assessment supporting the proposed rule indicated that the cancer MIR associated with dioxin and furan emissions was 30-in-1 million, within (in fact below) the acceptability threshold from the Benzene NESHAP.  As required in the ample margin of safety analysis, we did evaluate a control option that would further reduce emissions of dioxins and furans, but we determined those controls to not be cost-effective.  76 FR at 29050/3.  In addition, we note that a recent stack test submitted by Exide Frisco (i.e., the facility with the multipathway MIR of 30-in-1 million at proposal) during the public comment period show that emissions of dioxins and furans from this facility are in fact approximately 70 times lower than the emissions used as inputs used in the multipathway risk assessment.  Taking this into consideration, we believe that the multipathway MIR for this facility would be appreciably less than 1-in-1 million.  Moreover, the cost effectiveness of use of an afterburner remains quite high as it was at proposal ($105,000/gram reduction).  Use of high temperature afterburners to control a modest additional increment of dioxin not only has very poor cost-effectiveness, but has adverse environmental impacts in the form of increased NOx emissions, and increased energy use with attendant CO2 emissions.  76 FR at 29050/3.Taking all these factors into consideration, we maintain that it is not appropriate to require further control to provide an ample margin of safety.  
      Moreover, this same analysis supports not adopting beyond-the-floor standards for CDD/CDF pursuant to section 112 (d)(2) and makes it unnecessary to have further control under section 112 (d)(6).  The EPA also disagrees with the commenter that such factors as energy use, and increased NOx and CO2 emissions, are irrelevant in making determinations under section 112(d)(6).  Technologies with ultimate adverse environmental implications do not have to be regarded as `best' or `maximum'.  See  Essex Chemcial Corp. v. EPA, 486 F. 2d 427, 439 (D.C. Cir. 1973); Portland Cement Assn v. Ruckelshaus, 486 F. 2d 375, 385 n. 41 (D.C. Cir. 1973).  Moreover, the fact that the EPA must consider "energy requirements" in adopting standards under section 112(d)(2) makes it reasonable to review those requirements when conducting further analysis pursuant to section 112(d)(6).  Adverse environmental implications of additional energy use are an aspect of that consideration.
      Comment:  Commenter 98 stated that the EPA failed to carry out a technology review for THC emissions from the category.  The commenter notes that the EPA clearly states that "[n]o changes are being considered in this action for the THC limits for blast and collocated last and reverberatory furnaces established in the 1997 NESHAP."  The commenter contends that this omission fails to satisfy section 112(d)(6).
      Response:  In the technology review conducted for this source category, the EPA did consider additional controls for organic HAP emissions.  As described in the Technology Review for the Secondary Lead Smelting Source Category document at page 8 (available in docket ID EPA-HQ-OAR-2011-0344), we did not identify new control technologies that would achieve reductions in organic HAP emissions beyond the limits considered in the current NESHAP.  However, we do believe that facilities may be able to achieve additional reductions in organic HAP emissions by designing and operating an afterburner with a higher temperature and residence time.  However, because the reverberatory furnace often operates at temperatures higher than those that can be reasonably achieved by an afterburner, this option is only feasible for blast furnaces.  The EPA considered additional afterburner capacity for blast furnaces as a beyond-the-floor option for organic HAP, but decided against requiring this control after a consideration of potential emission reductions, cost, and non-air environmental impacts. The beyond-the-floor option would achieve roughly 300 tpy in reductions of THC. However, this option would impose about $2.9 million dollars total annualized cost on the industry and achieve no significant environmental benefit or reductions in public health risks. The adverse energy implications associated with operating an afterburner, with attendant carbon and NOx pollution, also makes this an undesirable option. 
   b. Mercury
      Comment: Commenter 98 states that Section 112(d)(6) and 112(d)(3) each require the EPA to set a numerical limit for mercury emissions. The commenter stated that it is necessary for the EPA to close inherently unlawful gaps in the original MACT by setting a standard for an uncontrolled HAP and that the EPA must set an emission standard for each HAP listed on the section 112(b)(1) list that this source category emits, including mercury.  The commenter argued that the EPA's own test showed that, for 32% of the data set, mercury emissions were above the detection level; therefore, the EPA did have and did use some information on mercury emissions to perform the risk assessment.  The commenter suggests that the EPA could set the MACT limit using the data it used to perform the risk assessment for those sources with emissions below the detection threshold.  Additionally the commenter stated that the EPA has failed to demonstrate that this proposal provides an ample margin of safety for public health from mercury emissions.
      Response:  EPA did not set a standard for mercury in the original MACT rule and is rectifying that deficiency (see National Lime, 233 F. 3d at 634) here by establishing standards pursuant to sections 112 (d)(2) and (3).  The commenter further maintains that it is impermissible to establish a work practice standard because the criteria under section 112 (h) aren't satisfied since emissions of mercury from these sources were measured in a limited number of instances.  Section 112 (h)(1) and (2)(B) indicate that EPA may adopt a work practice standard rather than a numeric standard when "the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations." 
      The majority of the mercury data collected during the ICR test program for this rulemaking was below the limit of analytic detection. Under these circumstances, EPA does not believe that it is technologically and economically practicable to measure mercury emissions from this source category.  "[A]pplication of measurement methodologies" (section 112 (h)(2)(B)) means more than taking a measurement.  It must also mean that a measurement has some reasonable relation to what the source is emitting, i.e. that the measurement yields a meaningful value.  That is not the case here and EPA therefore does not believe it reasonable to establish a numerical standard for mercury in this rule. Moreover, a numerical limit established at some level greater than the detection limit (a necessity since any numeric standard would have to be measurable) could actually authorize and allow more mercury to be emitted than would otherwise be the case.
       Mercury control can occur as a "cobenefit" of conventional control technologies that have been installed for other purposes. Particulate-bound Hg can be effectively removed along with other flue gas PM (including non-Hg metal HAP) in the primary PM control device. Fabric filters (FF) have been shown to provide very high levels of control when there is adequate halogen (or other oxidant) available to convert the Hg to the oxidized form. See 76 FR at 29051 and Control of Mercury Emissions from Coal Fired Electric Utility Boilers, available at http://www.epa.gov/ttn/atw/utility/utiltoxpg.html.  The stack emission standard for lead is predicated on optimized performance of a well-maintained new baghouse.  We thus believe that this standard will also result in the level of control of the exceedingly small amounts of mercury present in secondary lead emissions achieved by the best performing facilities in the source category.  
      Comment:  Commenter 90 and 96 support the EPA's reasoning and conclusion that no work practice requirements for mercury are appropriate or necessary.  The commenters do not believe that the data confirm that mercury is actually emitted by the industry.
      Response:  The test data do indicate that a small amount of mercury is emitted from this industry, however, as described above, a numerical standard for this pollutant is not warranted. 
Risk Assessment
Risk Assessment Methodology
	
	Comment:  Two commenters (80, 86) support the use of CalEPA's acute REL for arsenic.
      Response:  We acknowledge the support.
      Comment:  Two commenters (86, 92) commended the EPA for using allowable emissions in its risk assessment for this source category.
      Response:  We acknowledge the support.
      Comment:  Two commenters (86, 92) commended the EPA for conducting multipathway exposure and risk modeling for those HAPs known to be persistent and bio-accumulative in the environment and for selecting facilities that represent the high end of potential risks from this source category.
      Response:  We acknowledge the support.
      Comment:  Commenter 92 stated that they were satisfied with many aspects of the residual risk assessment.  According to the commenter, the strengths of the risk assessment were,
      The use of facility specific emission point parameters,
      The review and use of emissions data from stack testing reports;
      The inclusion of allowable emissions when predicting risk under the proposed risk assessment,
      The inclusion of an analysis of the pre- and post-emission control impacts on the MIR
      The assessment of the available ambient lead monitoring data collected in the vicinity of these facilities, and
      The effort to conservatively assess the impact of fugitive emissions in a sound technical manner that goes beyond what other residual risk assessments have achieved.
      The commenter also stated that they agree with the use of the lead NAAQS with which to compare the predicted maximum modeled 3-month average lead concentration as the NAAQS was "rigorously derived to protect public health with an adequate margin of safety."
      Response:  We acknowledge the support.
      Comment:  Four commenters (80, 86, 92, 98) disagreed with the use of the census block centroid to determine risk from the facilities' emissions.  Commenter 86 argues that using the census block centroid to estimate risk "dilutes the effect of sources' emissions by estimating the impact at the centroid of the census block instead of at the facility fence or the property line."  Commenter 86 noted that in larger census blocks, the maximum point of impact can be far from the centroid.  Commenter 86 further pointed out that non-developed areas near the property line can become developed over time.  Commenter 98 noted that the center of a census block is almost always further away from the facility than the fenceline.  Commenter 98 stated that census blocks vary greatly in size but the EPA provided no evidence of reviewing census block sizes or configurations to consider how pollutant concentrations might vary within these blocks.  Commenter 98 is concerned that the area-weighted centers of census blocks may significantly underestimate exposure in some cases and recommends moving receptor points closer to the facility to assess chronic exposure in those instances where local residents live nearer to a facility than the geographic centroid of the census block.  All four commenters noted that HEM-3 gives the EPA the capability to identify that maximum individual risk at any point in a census block that is within a 50-km radius from the center of the facility.
      In response to the above comments, two commenters (90, 96) noted that the EPA "estimated the MIR associated with each facility by purporting to determine the risk associated with a lifetime exposure at the highest concentration outside the property boundary..."  These commenters further noted that the census block centroid risk estimates were used only to "estimate population risks and that if EPA considered only the maximum individual risk in each census block, there would be no information from which to estimate populations risks."
      Response: As we have noted in the development of previous residual risk regulations, such as the HON, in a national-scale assessment of lifetime inhalation exposures and health risks from facilities in a source category, it is appropriate to identify exposure locations where it may be reasonably expected that an individual will spend a majority of his or her lifetime. Further, in determining chronic risks, it is appropriate to use census block information on where people actually reside, rather than points on a fenceline, to locate the estimation of exposures and risks to individuals living near such facilities. Census blocks are the finest resolution available as part of the nationwide population data (as developed by the US Census Bureau); each is typically comprised of approximately 40 people or about 10 households. In EPA risk assessments, the geographic centroid of each census block containing at least one person is used to represent the location where all the people in that census block live. The census block centroid with the highest estimated exposure then becomes the location of maximum exposure, and the entire population of that census block is assumed to experience the maximum individual risk. In some cases, because actual residence locations may be closer to or farther from facility emission points, this may result in an overestimate or underestimate of the actual annual concentrations (although there is no systematic bias for average levels). Given the relatively small dimensions of census blocks in densely-populated areas, there is little uncertainty introduced by using the census block centroids. There is more uncertainty when census blocks are larger, although there is still no systematic bias. Thus, the EPA concludes that the most appropriate locations at which to estimate chronic exposures and risks are the census block centroids because: 1) census blocks are the finest resolution available in the national census data, 2) facility fence lines do not typically represent locations where chronic exposures are likely (i.e, people do not typically live at the fence line of facilities) and 3) as just described above, there is no systematic bias with respect to using census block centroids as an exposure surrogate for all individuals residing in that block.
	This has been EPA's approach for estimating chronic maximum individual exposures and risks throughout the RTR program.  In addition, in its peer review of the methodologies used to estimate risks as part of the RTR rulemaking efforts, the EPA's Science Advisory Board (SAB) endorsed this approach.
      Comment:  Two commenters (90, 96) stated that the EPA should not use the CalEPA's acute REL for arsenic because it is "invalid and substantially overestimates acute risks from arsenic exposure."  The commenters noted that the California REL relied on the Nagymajtenyi study which did not evaluate the fetal effects on a litter basis, therefore making it impossible to determine whether the observed effects were due to arsenic exposure or other litter effects.  The commenters cited a similar study "that was conducted in accordance with appropriate guidelines" in which researchers observed no fetal effects at As2O3 concentrations of 10 mg/m[3].  The commenters also stated that the fact that the California REL is approximately 100 times lower than that for arsine gas despite the fact that arsine gas is much more toxic than As2O3 is anomalous.  So too, according to the commenters, is the fact that despite the greater toxicity of arsine, a study conducted by the National Toxicology Program showed "no evidence of developmental toxicity in either rats or mice at concentrations up to 2.5 ppm..."  The commenter further noted that use of the California REL is "inconsistent with and would constitute a departure from EPA's practice, which has considered a fetal weight reduction of 0.1 g to be not toxicologically significant."  The commenter also argued that the California REL is inconsistent with ATSDR's guidance, which deems 0.26 mg/m[3] to be a NOAEL rather than a LOAEL.  The commenter stated that the EPA should either not attempt to quantify acute arsenic risks or should correct the California REL by increasing it by at least an order of magnitude, citing the Morrissey study that suggests that the California REL should be set at a level at least 100 times greater than the current standard.
	Commenter 92 stated that the state of New York did not adopt the California REL because "it is policy in New York to adopt the most stringent of either a non-cancer chronic or cancer air guideline concentration."  The commenter notes that New York multiplied the EPA's IRIS unit risk value for Arsenic of 2.3E-4 ug/m[3] by 65 to obtain a REL of 0.015 ug/m[3].
      Response: With regard to the acute Cal EPA REL for arsenic, the EPA recognizes that there are limitations associated with the database used in the derivation of this value. Nevertheless, given that the acute Cal EPA REL is the only existing peer-reviewed acute dose-response value, the EPA considers it reasonable to use this value for an acute analysis.  It is important to note that assessments of risks from acute exposures to HAPs represent worst-case scenarios, and that the estimated acute impacts of arsenic did not weigh heavily in the regulatory decision. 
      With respect to New York benchmark value for arsenic, we note that the EPA has a hierarchy of appropriate health benchmark values.  In general, this hierarchy places greater weight on EPA derived health benchmarks than those derived by other States or agencies (http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf).  Moreover, multiplying a chronic IRIS cancer value by 65 to obtain an acute REL is an arbitrary approach that to our knowledge, has not received favorable scientific support or been subject to peer review.
      Comment: Two commenters (90, 96) claimed that the EPA's risk review violated section 112(f)(2) because it considered risk from sources that are not part of the secondary lead smelting source category.  The commenters noted that by including facility-wide emissions the EPA may overestimate risks associated with the secondary lead smelting industry and promulgate risk-based standards for risks that are not attributable to its emissions.  The commenter further stated that "it would be unlawful for EPA to use information from the National Air Toxics Assessment or otherwise to include non-source category (or subcategory) risk in setting standards pursuant to Clean Air Act § 112(f)(2).  The commenter similarly noted that by proposing emission standards based on sources emitting lead at levels that exceed the NAAQS, the EPA is improperly considering background ambient lead concentrations in its analysis.
      Response:  The finding of unacceptable risk from the secondary lead smelting source category was based on risk estimates and emissions from the secondary lead source category.  More specifically, we found estimated risks resulting from secondary lead smelting emissions at these facilities to be unacceptable primarily based on source category emissions of lead compounds. See 76 FR at 29054-29055. The finding of unacceptable risk was not based on emissions or estimated risks associated with the facility wide analysis. In addition, we disagree with the comment that the EPA is "improperly considering background ambient lead concentrations in its analysis."  The estimates of lead risk in the risk assessment, as well as the controls in the final rule, are based solely on emissions from the facilities in the secondary lead smelting source category.  They do not take into account additional sources that may be outside the source category contributing to ambient lead background concentrations.
      Comment:  Four commenters (90, 91, 94, 96) argued that the EPA's risk review is invalid because it is predicated on risks to hypothetical populations that may not exist.  The commenters cited the specific example of the EPA's estimated multipathway risk to Laotian anglers near the Exide Technologies facility in Frisco, Texas.  The commenters contend that census statistics indicate that the Laotian population in this area of Texas is very small and that the EPA should demonstrate that there are actually Laotian anglers who consume fish from Lewisville Lake.
      Commenter 94 stated that, in the case of the Laotian anglers, multiple layering of conservative assumptions result in an unrealistic and overstated estimate of risk.  The commenter further stated that there is no evidence that particular groups in Texas eat exceptionally high amounts of fish.  Moreover, even ethnic groups that eat high amounts of fish will not continuously eat exclusively fish from one corner of Lewisville Lake for 70 years.
      The commenters also stated that the EPA's risk assessment erred in its estimate of fish concentrations in Silver Lake near the RSR facility in Middletown, NY. The EPA stated in its risk assessment that Silver Lake is too small to support fishing unless it is stocked regularly.  The commenters noted that stocking reduces the exposure period for fish and decreases expected fish tissue concentrations relative to lakes where fish are not stocked.  The commenters further noted that there is no indication in the risk assessment that the EPA has considered this factor in their risk calculations.
      Response:  We agree with the commenter that some of the risk estimates presented in the multipathway analysis reflect conservative assumptions.  As noted in the risk assessment document, in order to more fully characterize the potential multipathway risks associated with high end consumption of PB-HAP contaminated food, we present results based on reasonable maximum exposure (RME) and central tendency estimate (CTE) scenarios.  The RME scenario utilizes 90th percentile ingestion rates for farmers, recreational anglers, and for three subpopulations of recreational anglers) who have higher rates of fish consumption (Hispanic, Laotian, and Vietnamese descent), while the CTE scenario utilizes mean ingestion rates for each of these groups.  We provide results from both scenarios to illustrate the range of potential modeled exposures and risks that may exist in the high-end of the complete distribution of potential multipathway risks for this source category.  In addition, the risk assessment document also notes the risk range for the entire distribution of recreational anglers, which have significantly lower rates of fish consumption than the three sub populations mentioned above. Thus, in order to estimate a distribution of potential multipathway risks, we think it is reasonable to consider fish ingestion rates across multiple groups, including the Laotian population.  Moreover, we note that it is entirely possible that individuals other than Laotians may consume fish at any of the ingestion rates described in the multipathway assessment.  This again supports the use of a range of ingestion rates in order to estimate a broad range of potential multipathway risks. We further note that based on updated emissions estimates from the Frisco, TX case study facility, we now estimate that all multipathway risks from both case study facilities are less than 1-in a million (see final risk assessment document section 3.2).
      With respect to the comment that Silver Lake is too small to support fishing unless it is stocked regularly, we note that the TRIM.FaTE model does not currently model fish population dynamics, including processes like birth, death, growth, and stocking, although it does account for predation. Because the model estimates long-term concentrations in fish, it is unlikely that introducing changes to account for stocking would substantially impact the calculated PB-HAP concentrations in adult fish, especially if the fish are assumed to be stocked as fingerlings.
      Comment: Three commenters (90, 91, 96) disagreed with the use of the lead NAAQS as a hazard index.  The commenters argued that the lead NAAQS was based on only risks to young children, and that the EPA has inappropriately concluded that exceedances of the lead NAAQS result in unacceptable risks to adolescents and adults.  The commenters contend that hazard indices should not be presented in Tables A-5 through A-8 of the demographics analysis for age groups other than young children.
      Response: If the commenter is arguing that the proposed, and now final, standards for lead provide too much protection because they protect susceptible populations  -  notably young children living near lead emitting sources  -  and thus provide too much protection to other exposed individuals, this argument has been sharply rejected in the section 109 (d) NAAQS context (see Coalition of Battery Recyclers, 604 F. 3d at 617-18) and is just as misplaced here where EPA is charged to provide an ample of margin of safety in setting standards. Given that lead is a non-threshold pollutant, it is reasonable to use a metric for evaluating acceptability of risk which is based on assuring that the most susceptible sub-population is not exposed to unacceptable risk and thereby assuring that less susceptible populations are likewise not exposed to unacceptable risk.
      In addition, we disagree with the commenter that the lead NAAQS cannot be used in a quantitative manner. The review of the lead NAAQS clearly resulted in a quantitative standard: 3-month maximum lead concentration not to exceed a level of 0.15 ug/m[3]. This standard was set to protect public health, including the health of sensitive populations (i.e., children), with an adequate margin of safety. As the commenter notes, the lead NAAQS applies in all areas of the United States regardless of the age of the individuals living in a particular area. Thus, we find it appropriate to evaluate potential multipathway risks, in a quantitative manner, using the NAAQS for lead.
      Comment:  Five commenters (90, 91, 94, 96, 111) disagreed with the use of MACT-allowable emissions to estimate risk.  The commenters argued that the purpose of reviewing emissions under section 112(f)(2) is to assess the actual risks to people living near facilities in this source category.  Commenter 91 noted that "Nothing in § 112(f)(2) allows EPA to replace the statutory directive to examine what health risks are present at actual emission levels with a risk assessment that asks what health risks might be present a maximum allowable emission levels."  Commenter 91 further stated that less stringent rules would have likely been required had the EPA relied only on actual emissions to conduct its risk assessment.  Commenter 94 contends that even if allowable emissions are used for the risk assessment, the EPA should consider all applicable permit and legal limits on emissions.  The commenter specifically cited Exide's Frisco, Texas and Vernon, California facilities that are subject to more stringent limitations than what is specified in the NESHAP.  Based on the commenter's calculations, the EPA has overstated the allowable emissions at the Frisco and Vernon facilities by factors of three and 100, respectively.  Commenter 111 stated that the EPA's failure to provide a reasoned explanation as to why using MACT-allowable emissions to calculate risk is justified renders the proposal insupportable under the law.  The commenter stated that the EPA's risk assessment already reflects numerous conservative assumptions and that applying another layer of conservatism based on the hypothetical assumption that affected sources should be expected to emit more than the data indicates is not reasonable or justified.  The commenter points out that the EPA's own analysis indicates that all the facilities in this source category emit significantly less than what is allowed under the current MACT standard.
      Response: We have discussed the use of both allowable and actual emissions in previous actions, including 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 76603, December 21, 2006, respectively). In those previous actions, we noted that modeling the allowable levels of emissions (i.e., the highest emission levels that could be emitted while still complying with the NESHAP requirements) is inherently reasonable since they reflect the maximum level sources could emit and still comply with national emission standards.  Quite simply, in determining whether unacceptable residual risk remains after promulgation of section 112 (d) technology-based standards, it is reasonable to consider the emissions allowed by those 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. With regard to the comment that we failed to incorporate permit limits imposed on two facilities, we evaluated residual risk from allowable emissions remaining after compliance with the Secondary Lead Smelting NESHAP rather than permit limits that were, as the commenter says, more stringent than the requirements of the NESHAP.
      Comment:  Commenter 80 stated that area sources should be modeled as area sources rather than "pseudo point sources."  The commenter contends that forcing area emissions into point source "distorts their impacts on ambient concentrations."
      Response: Table 2.2-1 of the risk assessment document contained a typographical error. Area sources are modeled with a length, width and any other available characteristics at the proper location, not as point sources. This table has been corrected in the final risk assessment.
      Comment:  Commenter 80 stated that the use of a polar grid reduces the number of modeled receptors and makes it much less likely that the actual maximum concentration and location is modeled.
      Response: We disagree with the commenter that the use of a polar grid reduces the number of modeled receptors and makes it much less likely that the actual maximum concentration and location is modeled.  We note that the polar grid used in our exposure modeling utilizes a greater concentration of receptors in locations in close proximity to a given facility.  Thus, we have the greatest concentration of model receptors in areas where we would expect the site of maximum concentration to occur.   As a result, we believe that our polar receptor grid is sufficiently dense to capture the site of maximum concentration. 
      Comment:  Commenter 80 questions the use of meteorological data from 1991.  The commenter contends that there is ample data from more recent years and that improvements in the number and quality of meteorological instruments over the years makes using data that is twenty years old inappropriate.
      Response: When we began performing RTR risk assessments, we chose meteorological data considering the amount of data quality assurance needed, and AERMOD run times.  We restricted our meteorological data to that collected prior to the installation of the Automated Surface Observation System (ASOS). The ASOS had been found to omit the ceiling height for a large percentage of the observations at a number of meteorological stations.  Because installation and operation of ASOS equipment began in 1992, we selected the year 1991.  As newer, higher quality ASOS data have become available, we have added newer data and additional data site locations to the meteorological data library we use in our risk assessments.  Currently, approximately forty percent of our data is for years since 2000, and we will continue to process and add more recent data.  The commenter did not provide evidence regarding their comment questioning the quality of meteorological instruments.
      Although five years of meteorological data is preferred for assessing chronic exposures and risks, we use a single year of meteorological data in our risk assessments because of AERMOD model run times.  Because we frequently run AERMOD for entire source categories with many individual emission points and for many receptors, using five years of meteorological data would increase already significant model run times by a factor of five compared to a single year.  In a sensitivity analysis of the impact of using a single year of meteorological data compared to five years, we found that modeled concentrations differed by less than ten percent on average and thus, the use of one year of meteorological data is not likely to appreciably affect the results of the risk assessment. 
      Comment:  Two commenters (86, 92) questioned why certain factors recommended by the EPA in the EJSEAT were not considered in the risk assessment for this industry.  Commenter 086 stated that the EPA should consider addressing existing disproportionate impacts on minority, low-income or indigenous populations during rulemaking.  Commenter 86 further recommended that the EPA conduct a full evaluation of how the risk assessment for this source category could reduce risks to those communities.  Commenter 92 stated that the evaluation should have included an assessment of childhood blood-levels in neighborhoods near the smelters.
      Response: We note that EJSEAT is currently a draft tool in development.  The EPA disagrees that a full assessment of child blood-levels should have been included in its risk assessment.  We note that the NAAQS for lead was used as a health benchmark value in our risk assessment and in developing the NAAQS for lead, child blood-lead levels were already taken into account. See section V.A in the final rule preamble and later responses in this document. Moreover, we also note that we did a demographic analysis for this source category and with respect to lead risk, we found that the percentages of specific demographic groups (e.g., minority groups, those below the poverty level) living around these facilities in areas with lead concentrations above the NAAQS for lead is similar to the corresponding national percentages for these groups.  In addition, we performed a similar analysis with respect to cancer risk above 1 in a million.  In brief, although we did find the percentage of some demographic groups around these facilities with cancer risks above 1 in a million to be higher than their corresponding national percentages (e.g., a greater percentage of minorities and those below the poverty level live around secondary lead facilities and have a cancer risk greater than 1- in a million compared to the national percentages for these groups; see Risk and Technology Review - Analysis of Socio-Economic Factors for Populations Living Near Secondary Lead Smelting Facilities in the docket for this rule), we note that post-control cancer risks were substantially reduced for all demographic groups.  For example, the pre control MIR was estimated to be about 50 in a million, but the post-control MIR was reduced to 7 in a million (see Residual Risk Assessment for the Secondary Lead Smelting Source Category available in the docket for this rule).  
      More important, what matters is whether persons of whatever demographic exposed to emissions from secondary lead smelters would experience an unacceptable level of risk.  The rule will result in lead exposures which are less than the lead NAAQS and substantially reduced cancer risks. The NAAQS is itself predicated on being protective with an adequate margin of safety to the most susceptible sub-population:  children living near these sources who are exposed at the level of the standard. The NAAQS accounts for multi-pathway impacts of long-term emissions, as well as the differential incremental risk of Pb faced by populations at different levels of exposure.  See section V.A of the final rule preamble and later responses in this document.  These standards will therefore reduce risk of exposure to an acceptable level to all groups. 
      Comment:  Three commenters (90, 94, 96) argued that the EPA should more clearly state the conservative nature of its risk assessment.  Commenters 90 and 96 stated that the EPA overestimated the cancer incidence for population living around the smelters. The EPA estimates cancer incidence by multiplying the estimated cancer risk for each census block by the number of people living within the block.  Cancer risk for each census block is estimated by multiplying lifetime average exposure by a Unit Risk Exposure (URE).  The commenters contend that because cancer incidences are calculated on the basis of these URE's, the cancer incidences are upper bound estimates that may be lower than predicted and could be zero.  The commenter requested that the EPA clearly identify the cancer incidence estimates as upper-bound estimates and explain that actual cancer incidence could be as low as zero.
      Commenter 94 stated that the EPA should not make and layer conservative assumptions that yield risks that are clearly out of line with any risk faced in the real world.  The commenters cited the EPA's use of the maximum exposed individual (MEI).  The commenter contends that the use of the MEI alone results in an overestimation of cancer risks by at least a factor of three.  The commenter further cited the Superfund context in which the EPA "recognizes and places limits on the applications of conservative estimates..."  The commenter stated that the EPA should make clear the conservative nature of its assumptions and should also adopt a risk assessment approach that meets the Superfund reasonable maximum exposure (RME) definition.
      Response: The EPA disagrees with the commenter that it does not describe the nature of its risk assessments, including their limitations, uncertainties, and the possible interpretations of results.  Indeed, in this proposed rule and in the risk assessment documentation accompanying it, as in all RTR rulemakings, there are lengthy sections discussing the uncertainties associated with each step of the assessment process, including justifications for health-protective assumptions to cover uncertainty gaps, where appropriate.  As one example, the risk assessment clearly states cancer incidence estimates are upper bound and actual cancer incidence could be as low as zero.  The risk assessment states in section 2.7:
      
For each carcinogenic HAP included in an assessment that has a potency estimate available, individual and population cancer risks were calculated by multiplying the corresponding lifetime average exposure estimate by the appropriate URE.  This calculated cancer risk is defined as the upper-bound probability of developing cancer over a 70-yr period (i.e., the assumed human lifespan) at that exposure.  Because UREs for most HAPs are upper-bound estimates, actual risks at a given exposure level may be lower than predicted, and could be zero.
      
      The EPA further notes that it does not currently use the maximum exposed individual (MEI) metric in its chronic risk assessments, instead using the maximum individual risk (MIR) metric for the source category -- which is defined as the cancer risk associated with a lifetime of exposure at the highest concentrations associated with carcinogenic HAP emissions from the source category.  The MIR is estimated at a location where people live, whereas the MEI is estimated at a location on the property boundary of a facility (see section 2.3 of the final risk assessment for a description of the MIR and section 4.1 for a description of uncertainties associated with the MIR estimate).  See section 112 (f)(2)(A) allowing such an approach by its reference to "the individual most exposed to emissions from a source in the category" which can certainly be read to refer to lifetime exposure where people reside.  Put another way, in assessing chronic risk, it is more reasonable to assess risk based on where people may reside for 70 years, than to assume exposure for 70 years at a location (a property fenceline) where people do not reside for a lifetime.
      Comment:  Commenter 92 states that the EPA should have conducted the socio-economic analysis separately for each of the 14 secondary lead smelting facilities, rather than combining the outcome for all the facilities.
      Response: The EPA disagrees that it should have conducted the socio-economic analysis separately for each of the 14 secondary lead smelting facilities, rather than combining the outcome for all the facilities.  As noted in the preamble and demographics analysis, the purpose of the demographics analysis was to identify demographic groups that may be impacted by the proposed rule.  For this purpose, the EPA believes that a source-category wide socio-economic analysis is a reasonable approach.
      Comment:  Commenter 91 questioned several aspects of the air dispersion modeling conducted by the EPA, including:
      Failure to account for dry depletion.
      Failure to include building profile data in downwash calculations.
      Using one degree rather than 7.5 minute to estimate ground level and hill height elevations close to a source.
      Failure to rely on actual boundary data.
      Mischaracterizing the stack height and diameter and exit temperature and location of two sources at the Doe Run facility.
      Modeling fugitive emissions with a release height of 10 feet rather than as being emitted from a building that is 80 feet high.
      Including results from two monitors located within Buick Recycling's fence line and relying on a three-month average lead concentration level that occurred during upset condition.
      Lack of clarity regarding whether allowable emissions incorporated enforceable emission restriction that are currently in place.
      
      Response:  We agree that accounting for dry depletion would result in lower estimated air concentrations.  However, the impact of dry depletion on gaseous emissions is usually not significant, and for particulate emissions the impact depends on multiple factors, including the distance from the source to the receptor, and particle properties.  The impact of depletion on maximum estimated air concentrations and risks likely would be minimal because of the short distance between the sources and receptors.  At longer distances, the impact would be greater, but the extent of that impact is difficult to estimate because we typically do not have sufficient particle property data (aerodynamic particle diameters, particle densities, and mass fractions) to model depletion.  Also, deposited emissions can be resuspended in the air, and plume depletion does not account for that.
      We agree that, in certain cases, building downwash can result in higher estimated air concentrations near buildings (up to five to ten building heights away).  However, the impact of downwash on maximum estimated  exposures and risks is likely not significant because the receptors we use to estimate chronic exposures (populated census block centroids) are typically farther from the source.  Downwash would have an even lower impact on cancer incidence and population risks because those are driven by receptors even farther from the source.  Also, the detailed building information required to model building downwash is usually not available for most sources.
      For RTR risk assessments, we have used 1-degree elevation data, which has a resolution of approximately 90 meters.  We used this elevation data to compute the elevation and hill height scale for each populated census block (2000 Census) in the nation, which is approximately six million blocks.  This was done over a decade ago, and at that time, EPA's modeling guidance (40 CFR 51, Appendix W) did not require the use of 30-meter resolution data for regulatory applications.   We used the 1-degree data because of its availability and because of computational efficiencies with interpolating the data for the approximately six million census blocks.  For future RTR assessments, we will use the 2010 Census data and 30-meter resolution elevation data.
      Detailed facility boundary information is typically not available for most of the sources we assess for RTR, but the lack of this information does not have a significant impact on our risk assessments.  For chronic exposures, we use populated census block centroids as surrogates for where people live, so facility boundaries are not relevant.  For acute exposures, we estimate the highest concentration outside facility boundaries, and boundary information would be useful.  In cases where estimated acute concentrations exceed relevant health reference values, we do need some source of information on facility boundaries, and we typically use publicly available aerial images of facilities for this purpose.  Similarly, for lead we also estimate the highest concentration outside facility boundaries and in instances where the NAAQS for lead is exceeded, we typically use publicly available aerial images of facilities for further refinement of concentrations.
      Finally, we note that the mischaracterized stack dimensions and exhaust temperatures at the Doe Run facility which were mischaracterized at proposal have been corrected and are reflected in the results of the final risk assessment document (see sections 3.2 and 3.3 as well as Appendix 5 of the final risk assessment document for updated risk estimates) . 
      We have noted the commenter's point that two of the monitor locations listed in the Summary of the Ambient Lead Monitoring Data near Secondary Lead Smelting Facilities were located on the facility property, and a corrected version has been included in the docket for this final rule. 
      We did not incorporate facility-specific permit limits that differed from the requirements of the secondary lead smelting NESHAP into the risk assessment. The assessment of allowable emissions focused on what is allowable after implementation of the NESHAP rather than facility-specific permit limits that may have been put in place for compliance with other regulations. 
      Comment:  Commenter 94 stated that the EPA's estimate of risk to farmers near the Exide Frisco facility is unrealistic.  The commenter noted that the 2001 land data that the EPA used to assign locations to the farms did not account for development that has occurred near the facility in the last decade.  Given the level of development that has occurred, the commenter contends that it is unlikely that the level of farming needed to provide all of a person's food would continue around the facility for 70 years into the future.  The commenter further argued that the assumption that a single individual is exposed via all pathways is unrealistic.
      Response: To characterize the surrounding land use for the Exide Frisco facility, EPA used the 2001 National Land Cover Database (NLCD) from the U.S. Geological Survey.  In late 2010 (i.e., November/December), when assigning input parameter values for the secondary lead smelter source category risk assessment, EPA reviewed Google Earth satellite imagery to ensure that the characterization based on the 2001 data still appeared to be reasonable.  Based on that review, EPA determined that the 2001 data adequately represented the surrounding land use of the Exide Frisco facility.  Although Google Earth does not provide the resolution necessary to quantify the land uses surrounding the facility in sufficient detail to use in TRIM.FaTE, the resolution is adequate to see areas of undeveloped land that appeared to be dedicated to agriculture (i.e., appeared to be either tilled or in pasture). Additionally, in November 2011, Google Earth was reviewed to respond to this comment, and based on an image dated March 31, 2011, the characterization of the farming scenario was still possible. However, as noted above,  based on updated emissions estimates from the Frisco, TX case study facility, we now estimate that all multipathway risks from both case study facilities are less than 1-in a million (see final risk assessment document section 3.2).
      EPA acknowledges that it is unlikely that an individual would be exposed to contaminants from emissions from this facility for an entire 70-year lifetime. However, to be protective of health, EPA assumes that a child grows into an adult in the vicinity of the facility and is exposed for their lifetime (i.e., exposure duration of 70 years).  This default assumption is used unless there is clear justification to vary the exposure duration.  EPA acknowledges that there has been development in the vicinity of the Exide Frisco facility and this development likely will continue.  However, that facility was modeled to encompass one of the likely worst case scenarios possible for the source category based on data for all of the facilities in the source category.   Moreover, even at the Exide Frisco facility, as noted above, there is still the potential for agricultural production and subsistence consumption patterns in the vicinity.  
      EPA also acknowledges that it is unlikely that one individual would be exposed to all of the ingestion pathways modeled in this assessment in the vicinity of the Exide Frisco facility for an entire lifetime.  However, EPA believes that the possibility exists, however remote, and in the absence of information suggesting otherwise, makes this health protective assumption. Such conservative assumptions are consistent with Agency policy for chemical risk assessment for which all existing and potential future facilities cannot be assessed.  Use of these assumptions in national-level risk assessments has been reviewed by the National Academy of Sciences and EPA's Science Advisory Board.  
      Comment:  Commenter 98 noted that the EPA stated that it has performed no risk assessment for some HAPs due to the fact that they have no peer-reviewed reference values for cancer or chronic non-cancer or acute effects.  The commenter stated that the EPA cannot simply ignore these risks and must, at minimum, add an uncertainty factor to account for the risk that these HAP may cause.  The commenter further stated that the EPA should "prioritize those HAPs for which it needs data in this rulemaking and the next upcoming rulemakings and ensure that the development of this process and IRIS review have sufficient funding and resources to get the job done."  The commenter contends that the EPA must set a regulatory deadline to review the current risk analysis and perform another residual risk rulemaking once additional data on reference values becomes available.
      The commenter also stated that the fact that the EPA did not state which HAPs currently have no reference value denies commenters the opportunity to provide comments or information to the EPA that could improve its risk assessment and is a violation of the Clean Air Act's public notice and comment provision.
      Response:  This issue was addressed by the EPA's Science Advisory Board (SAB) in their May 10, 2010, (EPA-SAB-10-007) response to the EPA Administrator; http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.  In that response, the SAB Panel recommended that, for HAPs that do not have dose-response values from the EPA's hierarchy list, the EPA should consider and utilize, as appropriate, additional sources for such values that have undergone adequate and rigorous scientific peer review. They further recommended that the inclusion of additional sources of dose-response values into the EPA's hierarchy should be adequately documented in a transparent manner in any residual risk assessment case study.  We agree with this approach and have considered other sources of dose-response data when conducting our risk determinations under RTR.  However, in some instances no sources of information in addition to the EPA's hierarchy are available. 
      The EPA agrees that we should ultimately develop toxicity values for all Hazardous Air Pollutants (HAPs) utilizing all credible and relevant toxicity information. The need to update assessments with newly available data as well as the need to complete toxicological assessments for all HAPs lacking dose-response assessments further increases the importance of Agency activities to streamline and fully utilize the EPA's already overloaded IRIS program.  To that end, the EPA has always prioritized for future IRIS assessments those HAP without dose-response values but with the greatest potential for public exposure.  As a result of this prioritization, while not all HAPs may have scientifically accepted dose-response values that can be used in residual risk assessments, it is clear that the vast majority of HAPs which might carry the potential to significantly impact the results of residual risk assessments do, in fact, have credible dose-response values.  Thus, while we are not yet at the point where all HAPs have dose-response values, we are generally capable of deriving reasonable risk estimates for those HAP which dominate the risks from any one source category.  In the course of each residual risk assessment, should we encounter HAP without dose-response values which carry the potential to create significant risks, we shall clearly point those out as uncertainties and target them for future IRIS assessments.  Moreover, as additional dose-response values become available, the EPA will incorporate these dose-response values into future risk assessments.
      The EPA disagrees that with the commenter that we did not state which HAPs currently have no reference value.  In the risk assessment document, Table 3.1-1 lists all the HAP emitted by the source category, as well as whether there is an available cancer, chronic noncancer, and/or acute dose-response value.
      Comment:  Commenter 98 stated that the EPA underestimated risk to the most vulnerable populations by failing to account for the increased susceptibility of children and the developing fetus to HAP exposure.  The commenter stated that accounting for the increased susceptibility of infants and children to pesticides is required for risk assessments conducted under the Food Quality Protection Act and that the EPA should use this statute as a model to incorporate into its residual risk assessment.  The commenter contends that the EPA should "assume that the maximum exposed individual is a child or pregnant woman, conduct an evaluation of health risks that incorporates impacts from early life exposure, and set child-protective standards."
      The commenter further maintains that the primary lead NAAQS is an inappropriate measure of acceptability of risk "because it ignores the cumulative, long-term impacts to individuals in the local affected communities from prior lead emissions".
      The commenter maintains that "the CAA requirements for the level of a NAAQS are different from the standard for residual risk. What is acceptable at the population level is not necessarily acceptable at the community level." More specifically, the commenter asserts that "EPA must set a standard for those people living near facilities subject to the MACT who were left with insufficient protection... It is these specific communities near the facilities and the children living in these communities, and not a broad U.S. sub-population, that must be protected... The fact is that the lead NAAQS does not sufficiently protect people living near secondary lead smelters."  
The commenter further states that "in addition, replicating the lead NAAQS as an ambient standard is especially problematic because it ignores the cumulative, long-term impacts to individuals in the local affected communities from prior lead emissions that have occurred here and thus does not account for the full risk to communities near secondary lead smelters. EPA may not set a residual risk standard that primarily addresses ambient air. Past lead releases likely have created reservoirs of lead in the soils, vegetation, and dust in the area."  Based on this, the commenter argues that "if a community has a high level of lead in these other reservoirs, including the soil, there may well already be too much existing risk, such that no additional new lead emissions should be allowed to increase this risk."  
      
      With regard to lead emissions, the commenter stated that the EPA may not simply rely on the lead NAAQS to protect children.  The commenter stated that the EPA must incorporate the best available information, including the CHPAC recommendation and California's current health benchmark for children's blood-lead level change.  With regards to emissions of all HAP, the commenter stated that the EPA should examine developments in the methodology of California's Office of Environmental Health Hazard Assessment (OEHHA)'s that could affect the development of RfC and URE values.  The commenter also stated that the EPA should consider and apply its 2008 handbook on child-specific exposure factors.
      The commenter expressed support for the EPA's implementation of the 2005 Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens in the assessment of cancer risk from POM emissions, but contends that the EPA should follow the lead of OEHHA on the issue of age-dependent adjustment factors for carcinogens.  The commenter noted that the 2005 Supplemental Guidance was generated in 2006 and must be updated to incorporate more recent evaluations of carcinogenic modes of action.  The commenter further noted that the 2005 Supplemental Guidance does not account for increased cancer risk resulting from prenatal exposure.
   The commenter stated that the EPA's lack of analysis regarding increased early life susceptibility to HAP emissions "systematically underestimates risk" from the following pollutants:
   * Hexavalent Chromium
   * Dioxins
   * Arsenic
   * Cadmium
   * POM
      The commenter stated that failing to account for early life vulnerability and increased risks to children adds additional uncertainty to the risks from this source category.  The commenter noted that the Food Quality Protection Act uses an uncertainty factor of ten to account for this type of increased uncertainty and recommended that the EPA, at a minimum, do the same.
      
RESPONSE: The commenter is mistaken both that the EPA applied the lead primary NAAQS unthinkingly as a measure of acceptable risk, and further mistaken in its argument that the primary lead NAAQS is an inappropriate measure of risk acceptability (for lead) here because (according to the commenter) it is not designed to, and does not protect sensitive populations living near secondary lead smelters. 
	First, the lead NAAQS primary standard targets protection to the most susceptible group in the human population  -  children  -  and is designed to protect against adverse effects to children's most sensitive organ system  -  the developing neurological system. See 73 FR at 66975, 66976. Second, the primary NAAQS for lead is specifically targeted at those children living near major sources of lead, such as secondary smelters. See 73 FR at 67002/3 ("in applying the evidence-based framework, we are focused on a subpopulation of U.S. children, those living near air sources and more likely to be exposed at the level of the standard"); to the same effect see 73 FR 67000/3--("The framework in effect focuses on the sensitive subpopulation that is the group of children living near sources and more likely to be exposed at the level of the standard. The evidence-based framework estimates a mean air-related IQ loss for this subpopulation of children; it does not estimate a mean for all U.S. children";). 73 FR 67005/1--("the air-related IQ loss framework provides estimates for the mean air-related IQ loss of a subset of the population of U.S. children, and there are uncertainties associated with those estimates. It provides estimates for that subset of children likely to be exposed to the level of the standard, which is generally expected to be the subpopulation of children living near sources who are likely to be most highly exposed.")  In addition, in reviewing and sustaining the lead primary NAAQS, we note that the D.C. Circuit specifically noted that the rule was targeted to protect children living near lead sources:  

      "EPA explained that the scientific evidence showing the impact of lead exposure in young children in the United States led it `to give greater prominence to children as the sensitive subpopulation in this review' and to focus its revision of the lead NAAQS on the `sensitive subpopulation that is the group of children living near [lead emission] sources and more likely to be exposed at the level of the standard.'  Given the scientific evidence on which it relied, EPA's decision to base the revised lead NAAQS on protecting the subset of children likely to be exposed to airborne lead at the level of the standard was not arbitrary or capricious."    Coalition of Battery Recyclers, 604 F. 3d at 618.

The commenter further maintains that the primary lead NAAQS is an inappropriate measure of acceptability of risk "because it ignores the cumulative, long-term impacts to individuals in the local affected communities from prior lead emissions". EPA has not ignored such exposures.  First, as part of the Risk and Exposure Assessment supporting the lead primary NAAQS, the EPA assessed the IQ loss associated with the cumulative environmental impact of long-term emissions in communities living near stationary sources of lead emissions, specifically lead smelters. See Lead Human Exposure and Health Risk Assessments for Selected Case Studies; Volume I Human Exposure and Health Risk Assessments 00 Full Scale; and Volume II: Appendices ((USEPA, 2007) (Office of Air Quality Planning and Standards, Research Triangle Park, NC EPA-432/R-07-014a and EPA-452/R-07-014b; see also 73 FR 66979-66983.  The Risk and Exposure Assessment assessed exposure to lead from the inhalation route as well as the multiple ingestion pathways. Although the EPA relied primarily upon the evidence-based framework (i.e. epidemiological studies and related information) in developing the lead primary NAAQS, the EPA nonetheless found the air-related lead risk estimates from the Risk and Exposure Assessment to be generally supportive of that scientific evidence-based framework. (See 73 FR at 67003-04.)  
The evidence-based framework used in developing the lead NAAQS is focused on children with total lead exposure closer to the current U.S. average (than the more highly lead exposed upper percentiles of the population), since these children will have greater response to each increment of air-related lead exposure than would children with higher overall blood lead levels. 73 FR at 66976-77.  Other populations, including children with higher blood lead levels due to past exposures, will necessarily be accorded protection from air-related lead as well. (See EPA-HQ-OAR-2006-0735-5894 at page 13).
      The commenter nonetheless noted that in setting the NAAQS, the EPA recognized that there would be greater impacts to the more exposed individuals.  The commenter contends that children living near secondary lead smelters are not only a population with increased susceptibility, but they also face elevated levels of exposure because they live near secondary lead smelters. The commenter states that EPA's staff paper for the lead NAAQS shows that children living near the lead smelting facilities would still be subject to an IQ loss as high as 3.9 (at the median) to 7.3 (at the 95[th] percentile), even if the EPA had set the NAAQS at 0.02 instead of 0.15 ug/m[3].  The commenter stated that this shows that an ambient air concentration of 0.02 ug/m[3] would not achieve an acceptable level of risk for children living near a secondary lead smelter, let alone provide an ample margin of safety. The commenter stated that the EPA must set a residual risk standard that prevents the local ambient lead concentration from exceeding the CHPAC-recommended limit of 0.02 ug/m[3] as a monthly average. 
      The commenter contends that in choosing the lead NAAQS, the EPA "chose to allow an IQ point loss for the children...living near lead smelting facilities, above the 1 to 2 points that is considered to be "highly significant from a public health perspective," and above the 2 points that is considered to allow an "adequate margin of safety" for the national population level of exposed children."  Therefore, the commenter contends, "replicating the NAAQS"  in this rulemaking fails the section 112(f)(2) test to provide an ample margin of safety to communities near secondary lead smelters.
      The EPA disagrees. In establishing the 2008 Pb NAAQS, EPA recognized that more highly exposed individuals were at risk of greater adverse effects from lead, and EPA promulgated a revised Pb NAAQS that would provide the requisite degree of protection, with an adequate margin of safety, for the health of these individuals, specifically targeting protection at children living near sources of lead emissions exposed at the level of the standard, as demonstrated above.  EPA did not find that this standard would result in still greater IQ loss for children living near lead sources.  As shown above, these are precisely the susceptible subpopulation at which the standard is targeted.  EPA's determination that this susceptible subpopulation would be exposed to an air-related IQ loss of no more than 2 points was supported by the evidence-based framework (i.e. epidemiological studies and related materials) that was the primary basis for EPA's decision.  See 73 FR at 67006, where the Agency explained 
      The Administrator notes that the evidence-based framework indicates that for standard levels above 0.15 ųg/m3, the estimated mean air-related IQ loss in the subpopulation of children exposed at the level of the standard would range in almost all cases from above 2 points to 5 points or more with the range of air-to-blood ratios considered. He concludes, in light of his consideration of all of the evidence, including the framework discussed above, that the protection from air-related Pb effects at the higher blood Pb levels that would be allowed by standards above 0.15 ųg/m3 would not be sufficient to protect public health with an adequate margin of safety.  In addition, the Administrator notes that for standard levels below 0.15 ųg/m3, the estimated mean IQ loss from air-related Pb in the subpopulation of children exposed at the level of the standard would generally be somewhat to well below 2 IQ points regardless of which air-to-blood ratio within the range of ratios considered was used. The Administrator concludes in light of all of the evidence, including the evidence-based  framework, that the degree of public health protection that standards below 0.15 ųg/m3 would likely afford would be greater than what is necessary to protect public health with an adequate margin of safety.  
      
      The commenter appears to basing its assertions on portions of EPA's quantitative assessment report prepared for the primary Pb NAAQS prepared as part of the NAAQS review process.  EPA - 452/R - 07 - 014a and EPA - 452/R - 07 - 014b.  The commenter goes too far.  Although the results of the risk assessment were generally supportive of the evidence-based air-related IQ estimates, EPA did not rely on those estimates in establishing the level of the standard.  See 73 FR at 67006.  The lead NAAQS was based primarily on the scientific evidence and to a lesser extent the results of the risk and exposure assessment -- that is, on the epidemiologic information rather than on the exposure and risk assessment due to that assessment's associated limitations and uncertainties (see 73 FR from 66979 to 66982). Thus, EPA disagrees that the current or previous risk assessment reports or Staff Papers provides a basis for concluding that the current NAAQS is inadequate to protect the health of children living near sources of lead emissions.  
      Furthermore, we disagree with the general comment that EPA does not consider the groups that may be most at-risk in its risk assessments (e.g, pregnant woman).  By providing protection to the most susceptible parts of the population  -  here, children living near lead sources exposed at the level of the standard  -  the standard necessarily provides protection to less susceptible populations.  73 FR at 67005/1.  Thus, the lead NAAQS was based on the prevention of adverse health effects of children based on preventing effects to the developing nervous system in children living near lead sources and exposed at the level of the standard. Similarly, when EPA derives exposure reference concentrations and unit risk estimates for non-lead HAP, it also considers the most sensitive populations identified in the available literature, and importantly, these are the values used in our risk assessments (see US EPA. (2002), .  A Review of the Reference Dose and Reference Concentration Processes.  EPA/630/P-02/002F. Risk Assessment Forum, Washington DC.  Available online at  http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf).   Finally, with respect to maternal exposure in utero specifically, we are unaware of literature that would allow for a robust characterization of risk during this stage of development.
      We further note that in developing the NAAQS for lead, 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.  More specifically, EPA assessed the IQ loss associated with the cumulative environmental impact of long-term emissions in communities living near stationary sources of Pb emissions, specifically Pb smelters. (USEPA, 2007; 73 FR 66979-66983, also see the Lead NAAQS Human Exposure and Health Risk Assessment available at http://epa.gov/ttn/naaqs/standards/pb/s_pb_cr_td.html).  As noted, these risk estimates were judged to be generally supportive of the scientific evidence that was the primary basis for revising the lead NAAQS (73 FR at 67004). Taken together, the EPA believes that the lead primary NAAQS is a reasonable benchmark to use in evaluating the potential for multipathway health effects from lead compounds.
      Furthermore, as noted in the risk assessment document for today's  rule, there is no RfD or other comparable chronic health benchmark value for lead compounds. That is,  in 1988, the 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." The EPA's IRIS assessment for Lead and compounds (inorganic) (CASRN 7439-92-1), http://www.epa.gov/iris/subst/0277.htm.
      In short,  this rule does not "replicat[e] the lead NAAQS as an ambient standard"  as the commenter would have it.  EPA is  using the lead primary NAAQS as a measure of determining whether risks posed by emissions of lead from this source category, after implementation of the section 112 (d) MACT standard,  are acceptable.  That is the first step of the process of determining what standards are protective of public health with an ample margin of safety under the methodology set forth in the Benzene NESHAP and its codification in section 112 (f)(2)(B).  In arriving at the standards adopted in this rule, we have necessarily conducted the second step of the process, the ample margin of safety analysis, considering such issues as technical feasibility and cost as well as the range of risk information relevant in the determination.  We  have evaluated risks posed by the emissions from this source category, found the risks to be unacceptable, and required further controls as a result.  We view these controls as reducing risk to an acceptable level to all groups with an ample margin of safety, considering not only risk but technical feasibility, cost, and cost effectiveness, as well as other factors relevant under the benzene NESHAP decision framework.  Our determination considers risk on a total facility basis.  We have explained that further controls on stack emissions are not justified based especially on considerations of cost and cost-effectiveness.  This conclusion is the same no matter how much cumulative exposure from previous emissions  is considered.. (In this regard, we note  that the commenter's assertions regarding past multi-media contamination, and potential for lead exposure from these sources other than ambient air, are unquantified and somewhat speculative.).  
      To the extent the commenter is arguing that this rule should be used to remediate  past soil deposits ("EPA may not set a residual risk standard that primarily addresses ambient air"), the comment goes too far.  Such remediation activities are conducted under other authorities, notably RCRA and CERCLA.    
      With respect to the comment concerning HAP emissions other than lead, the EPA disagrees with the commenter's assertion that the chronic noncancer health benchmarks used for the assessment are not protective of children.  The EPA uses RfC values and chronic REL values that are expressly derived with the intention of protecting sensitive subpopulations, including children (see U.S. EPA. (2002).  A review of the reference dose and reference concentration processes.  EPA/630/P-02/002F. Risk Assessment Forum, Washington DC.  Available online at  http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf.  With respect to cancer, the EPA uses the age-dependent adjustment factor approach referred to by the commenter, but limits the use of those factors only to carcinogenic pollutants that are known to act via mutagenic mode of action, in contrast to the OEHHA approach which uses them across the board for all carcinogens regardless of mode of action.  The EPA believes the OEHHA approach is unwarranted and overly conservative, and provides its lengthy rationale for this approach in the 2005 Supplemental Guidance, as referred to by the commenter.  With respect to the commenter's recommendation for EPA to use the California benchmarks developed explicitly for protecting children, we note that the EPA is currently evaluating whether or not it is appropriate to use the CalEPA child-specific reference doses, and further notes that there are currently no such values for HAP inhalation, so their current utility would be limited to PB-HAP which may be associated with non-negligible ingestion exposures.  That is, before using these child-specific reference doses, the EPA wants to evaluate whether they have been appropriately derived. In addition, the EPA has a hierarchy of appropriate health benchmark values and in general, this hierarchy places greater weight on the EPA derived health benchmarks than those from other agencies (see http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf).   Notably, this hierarchy favoring EPA benchmarks (when they exist) over all others has been endorsed by the SAB.
The commenter also makes the legal argument that the primary NAAQS provides an "adequate" margin of safety, but that section 112 (f)(2) requires that a residual risk standard provide an "ample" margin of safety, reasoning from this that a NAAQS cannot just be substituted as the measure for evaluating acceptability of risk and that some greater level of protection is required.  We do not accept the commenter's argument.  EPA is considering the primary NAAQS for lead --which incorporates an adequate margin of safety -- in determining which lead risks from air-borne lead from secondary lead smelters are acceptable or unacceptable.  Thus, to the extent the commenter's argument rests on the difference between `adequate' and `ample' margin of safety, the argument is misplaced   Margin-of-safety determinations for this rule are conducted separately, in accord with the two-step framework set forth in the Benzene NESHAP and the en banc opinion in Vinyl Chloride.  See not only Vinyl Chloride, 824 F. 2d at 1165, 1166 but NRDC v. EPA, 902 F. 2d  962, 973-74 (D.C. Cir. 1990) (distinguishing the NAAQS process, whereby the margin of safety analysis is incorporated as part of the standard without a two-step analysis, from residual risk determinations).   .  Using that framework, with its consideration of costs, cost-effectiveness, technological feasibility, and other factors set out in the Benzene NESHAP, we did not identify any additional controls beyond those that would need to be implemented to ensure an acceptable level of risk with an ample margin of safety.  EPA thus disagrees with the commenter that section 112 (f)(2) standards must be more stringent than a primary NAAQS as a matter of law.
      Comment:  Commenter 98 stated that the list of contaminants identified in the 2003 Risk Assessment Guidance as being both persistent and bio-accumulative (`PB') in the environment is inaccurate and ignores HAPs which present a multipathway risk.  The commenter noted, for example, that arsenic is a metal and is persistent in the environment.  Therefore, assessing arsenic risk solely from inhalation underestimates risks associated with ingestion of arsenic-contaminated soil and fish.  The commenter also stated that excluding lead from the multipathway risk assessment is not justifiable as lead is persistent in the environment and also bio-accumulates in biota.  
      The commenter further noted that restricting the multipathway risk assessment to only contaminants that bioaccumulate is not supported by the 2003 guidance.  The commenter contends that the 2003 Guidance does not direct that the multipathway risk assessment be limited to PB-HAPs.  
      The commenter further stated that excluding contaminants that persist in soils underestimates risks from HAPs emitted from secondary lead smelters and it is therefore insufficient to rely on the lead NAAQS standard as a benchmark for multipathway risk due to lead.  The commenter stated that "Only a forward calculation of the estimated cumulative and multipathway risk from the lead and other HAP emissions satisfies the requirements for the residual risk assessment."  The EPA may not simply assume that the lead NAAQS satisfies section 112(f)(2), but must actually perform the residual risk analysis required to set standards under section 112(f)(2), avoid unacceptable risk, and provide an ample margin of safety for public health.  The commenter noted that the lead NAAQS separated lead exposure into "recent" and "past" air and "did not include both categories equally in setting of the standard."
      Response: In the Air Toxics Assessment Library (see http://www.epa.gov/ttn/fera/risk_atra_main.html), we developed the current persistent and bioaccumulative HAP (PB-HAP) list considering all of the available information on persistence and bioaccumulation.  This list was peer-reviewed by the SAB, and it is reasonable to use it in the RTR program. Based on the limited available information on the persistence and bioaccumulation of arsenic, we do not believe that the potential for multipathway risk rises to the level of the PB-HAP currently on the list.  
      We disagree with the commenter that a separate multipathway risk assessment should have been performed for lead.  As noted in previous responses, the NAAQS for lead was used as a health based standard in this review but was not simply adopted mechanically, but rather is justified under the independent decision framework in section 112 (f)(2).  We note that the NAAQS for lead was set to protect, with an adequate margin of safety, the health of the most susceptible children and other potentially at-risk populations against an array of adverse health effects, most notably including neurological effects, particularly neurobehavioral and neurocognitive effects (which are the most effects to which children are most sensitive) (73 FR at 67007). We further note that in developing the NAAQS for lead, air-related multipathway effects were already taken into account.  That is, as noted at 73 FR at 66971:
      "As was true in the setting of the current standard, multimedia distribution of and multipathway exposure to Pb that has been emitted into the ambient air play a key role in 	the Agency's consideration of the Pb NAAQS."
      
	In addition, the commenter is correct that a distinction was made between "recent" and "past" air in the exposure and risk assessment to support the lead NAAQS review (73 FR 66980).   However, as explained in earlier responses of this document, EPA based the lead primary NAAQS primarily on the scientific evidence and to a lesser extent the results of the risk assessment. Thus, the distinction between "recent" and "past" air in the risk and exposure assessments had little effect on the final decisions reached in the lead NAAQS. 
      Comment:  Commenter 98 stated that the EPA failed to include an exposure scenario that assesses cumulative risk from HAPs in the urban environment and therefore potentially significantly underestimates risks from this source category.  The commenter noted that soil contaminants are of particular concern to children due to particular behaviors that increase their exposures via incidental ingestion.  The commenter contends that the EPA's failure to assess an urban child scenario as part of the cumulative risk assessment "ignores the exposure that may pose the most significant risk from this source category."
      The commenter further noted that the EPA's multipathway risk assessment relies on incidental soil ingestion exposures taken from the EPA's 1997 Exposure Factors Handbook.  The commenter stated that these values are outdated and that the EPA should use more recent studies and estimates found in the 2009 update to the handbook.  The commenter noted that the EPA also has a 2008 child-specific exposure factor handbook that it failed to consider.  The commenter also stated that risks from exposure to soil contaminants should evaluate both direct and indirect exposure.
      Response:  The criteria for selecting the facilities in the multipathway case study analyses are described in sections 2.4 and 2.5 of the Human Health Multipathway Residual Risk Assessment for the Secondary Lead Smelting Source Category (available in the docket for this rulemaking).  As noted in that draft document, the EPA believes that these locations are in the upper end of the potential for multipathway risks from this source category (see page 1 of the multipathway assessment available in the docket for this rule).   Thus, even though neither of these scenarios are in an urban environment, we believe that they were reasonable locations to conduct a multipathway assessment, especially considering that proximity to farm land and/or fishable lakes is a major consideration for a multipathway risk assessment.  With respect to our inhalation risk assessment, this assessment was conducted to evaluate exposures occurring within 50 km of each facility in the source category.  See 76 FR at 29039. Thus, any facilities located in urban areas would have been included in the inhalation risk assessment. 
      The commenter's assertion that EPA should have used estimates for children's soil ingestion from the updated (2009) Exposure Factors Handbook, instead of the 1997 Exposure Factors Handbook (`EFH'), is not well taken.  At the time of the multipathway assessment, the 2009 revision was a draft that had been released for public comment. Thus, it was premature to adopt conclusions from this type of draft document.  We now note that this document has recently been finalized, but that its use would not have yielded any change in the soil ingestion rates that were used in the analysis to support the proposed rule (as detailed below). 
      For adults, the recommended central tendency (i.e., mean) soil ingestion rate is 50 mg/day for both the 1997 EFH and the 2009 draft EFH; and this rate was used in the analysis underlying this rule. The 1997 EFH did not provide an upper percentile soil ingestion rate for adults; therefore, as noted in Table C-3 of Appendix C of the background document (Human Health Multipathway Residual Risk Assessment for the Secondary Lead Smelting Source Category), the EPA used an upper percentile value from Stanek et al. 1997. The draft 2009 EFH only provides an upper percentile ingestion rate for adults that is reflective of geophagy (i.e. dirt-eating) behavior, which we believe would result in overly conservative risk results and, as such, is not appropriate for this type of risk assessment. 
      As provided in Table C-3 of Appendix C of the background document Human Health Multipathway Residual Risk Assessment for the Secondary Lead Smelting Source Category, the Child-Specific EFH (CSEFH) was used by the EPA, where applicable, for child soil ingestion rates. The CSEFH-recommended central-tendency ingestion rate of 50 mg/day was used in the analysis (note that this value is one-half the mean 100 mg/day ingestion rate recommended for children in the 1997 EFH). However, for the upper percentile ingestion rate, the 1997 EFH recommended ingestion rate of 400 mg/day was used for young children (those less than 6 years old) because the 2008 CSEFH only provides upper percentile ingestion rates that are reflective of pica and geophagy behaviors, which, as noted above, we believe would result in overly conservative risk estimates. For older children (6 years of age and older) we assume the same soil ingestion rate as for that of the adult.
      With regards to incidental soil contamination, the EPA has estimated risks from both direct and indirect pathways. Direct routes of exposure include direct ingestion of soil and exposure through dermal contact. However, because it has been demonstrated in past analyses that exposure levels associated with dermal contact are but a small fraction of exposure levels associated with ingestion and inhalation pathways, dermal exposures were not assessed for secondary lead smelters. Indirect soil-exposure pathways are assessed through analysis of the consumption of produce and animal products that are grown or raised in contaminated soils.
      Comment:  Commenter 98 stated that the EPA's overall risk assessment is incomplete because it fails to add the inhalation and multipathway risk assessments in order to come up with a total risk that the EPA and the public can analyze.  The commenter contends that the EPA should use this total risk to determine whether or not the risks from secondary lead smelters are acceptable and what standards would be needed to provide an ample margin of safety.
      Response: The EPA disagrees with the commenter.  Even though it is highly unlikely that the same person would have the highest inhalation and multipathway risk (the premise behind adding the two types of risk), the EPA did include in its risk assessment document, a combined inhalation and multipathway MIR for the Exide Frisco facility (see section 3.2 of the draft risk assessment document, available in the docket for this rulemaking).  We note that of the two multipathway case studies, this facility was estimated to have the highest multipathway cancer risk, and the EPA therefore used it as the multipathway MIR facility for the source category.  However, we (as noted in several responses above), based on updated emissions information (i.e., emissions information received during the public comment period for the proposed rule which showed that emissions were lower than the EPA estimated at proposal), multipathway risk associated with the Exide Frisco facility are estimated to be well below 1-in a million. See section IV.A of the final rule preamble, section 3.2 of the final risk assessment document, and other comment responses for discussion of the updated Exide Frisco dioxin data.
      Comment:  Commenter 98 stated that the EPA underestimated the total risk that maximum exposed people are likely to face and also failed to account for the increased risk caused by a person's exposure to multiple HAPs by not performing a full cumulative risk analysis.  The commenter noted that the EPA's stated reasons for not addressing cumulative risk are "uncertainties."  The commenter stated that, where public health is concerned, uncertainty is not "a rational explanation".  The commenter contends that the EPA should follow SAB recommendations that the EPA conduct a sensitivity analysis to identify major uncertainties in the risk assessments, explain these risks clearly in the risk characterization section, and take steps to reduce them.
      The commenter further stated that if the EPA chooses not to calculate cumulative risk, then it should, "at minimum, use the fact that it knows there is a greater risk than it has calculated as a reason to find a lower cancer, chronic non-cancer, and acute threshold to be acceptable."  The commenter argued that the EPA has failed to gather the information needed to determine whether stronger standards are needed for this source category.
      Response: We disagree with the commenter's statement that our risk assessments do not consider cumulative risk. We note that our assessment of cancer risks is, in fact, cumulative, summing the risks associated with all carcinogens emitted by a facility (see risk assessment document, section 3.2). Similarly, the use of the target organ specific hazard index (TOSHI) for chronic non-cancer effects evaluates the cumulative effects of HAP on a given target organ. Further, our assessment is cumulative in that it considers all emission points within the fence line (since they are all covered by the MACT). Moreover, the lead NAAQS is a cumulative standard in that it considered all air-related exposures in its derivation as explained in comment response at pages 68-74. 
      Moreover, to provide the quantitative risk information necessary to inform RTR regulatory decisions, the EPA conducts a comprehensive assessment of the risks associated with exposure to the HAPs emitted by the source category (i.e., those emissions that can actually be affected by the specific rulemaking) and supplements that with additional available information about other possible concurrent and relevant risks. In some cases, we have additional information about HAP emissions that are outside the scope of the particular rulemaking but within the boundaries of the subject facilities. In other cases, we may have ambient HAP monitoring data that can be considered as part of the regulatory decision-making. In still other cases, we may have very little additional risk information that can be considered. In all cases, however, when we consider additional information about risks, we also consider its attendant uncertainties, and information which carries significant uncertainties generally carries much less weight in the overall regulatory decision.
      All of the quantitative risk assessment information about HAP emissions from the source category under consideration is also considered in the manner prescribed by the decision framework set forth by the CAA for residual risk decision-making (i.e., the Benzene NESHAP decision framework), and this means that the general guidelines of risk acceptability have been developed in a way that they already take into account the impossibility of accurately quantifying the health risks posed by outside forces on every individual in the population. This acknowledgment allows the EPA to make risk-based decisions by focusing on the risks associated with the emissions that are themselves the subject of regulation being considered.
      Comment:  Commenter 98 stated that, with regards to lead emissions, the EPA violated section 112(f)(2) by stopping once it determined the level of emissions reductions needed to avoid exceedances of the lead NAAQS.  The commenter contends that the EPA did not perform an analysis to decide whether reducing emissions to a level that would comply with the NAAQS would also reduce risk to an acceptable level.  The commenter noted that "what is acceptable at the population level is not necessarily acceptable at the community level."    The commenter stated that rather than setting a standard that would reduce emissions enough to comply with the NAAQS, the EPA must set a standard to reduce risks to an acceptable level.  The commenter also noted that the EPA may not consider cost in determining the reduction in emissions needed to reduce risk to an acceptable level.
      Response:  The EPA disagrees with the commenter  -  the NAAQS for lead did consider lead risks for children living around these types of facilities  -  i.e. considerations of risk at the community level.  As explained in the preamble for the lead NAAQS at 73 FR 67002/3:

      "More specifically, in applying the evidence-based framework, we are focused on a subpopulation of U.S. children, those living near air sources and more likely to be exposed at the level of the standard. While the air related Pb in the blood of this subpopulation is expected to be greater than that for the general population given their greater air-related Pb exposure, we do not have information on the mean total blood Pb level (or, more specifically, the nonair component) for this subpopulation. However, even if we were to assume, as an extreme hypothetical example, that the mean for the general population of U.S. children included zero contribution from air-related sources, and added that to our estimate of airrelated Pb for this subpopulation, the result would still be below the lowest mean blood Pb level among the set of quantitative C - R analyses
      
      See also comment response at pages 68-74 above, for further discussion of this issue.  
      
      Moreover, as noted in the preamble to the proposed rule, the lead NAAQS, a health based standard set to protect public health with an adequate margin of safety (including the health of sensitive populations), was chosen as a health benchmark to ensure that risks associated with lead exposure were acceptable.  See 76 FR at 29041-29042.  In using this benchmark to determine the highest level of emissions that could be associated with an acceptable level of air-borne risks to lead-bearing emissions from secondary lead smelters, EPA chose to ensure that the worst-case impact created by any source in the category was acceptable to the most sensitive individual in the entire population (which is, in this case, children living near the smelter and exposed to the level of the lead primary NAAQS), regardless of whether or not the most sensitive individual in the population (i.e., a child) was deemed to reside at that point of worst-case impact.  By protecting against the most susceptible subpopulation, other exposed but less susceptible populations will necessarily also receive protection, and not be exposed to unacceptable levels of lead. The EPA then considered in its ample margin of safety discussion whether additional cost effective, technically feasible controls were available to reduce risk further.  However, the EPA did not find any additional controls that were justified under the second step of the residual risk analysis.  
      Comment:  Commenter 98 generally commented that the EPA needs to update its framework for determining "acceptability" of risks under the RTRs to reflect more current science and societal mores as to what risks are considered to be acceptable.  The commenter notes that the science has evolved significantly since the late 1980's and they question why "100 in-a-million" cancer risk level is still appropriate in light of current science and evolving community standards (this later point based on language in the en banc Vinyl Chloride opinion).  The commenter stated that for non-lead emissions; the EPA presumes that the lifetime cancer risk here is "acceptable" because it is lower than 100-in-1 million. The EPA does not address or explain why any risk below that level remains acceptable today.  It is arbitrary and capricious for the EPA to continue to rely on that presumption as a basis for its decision for several reasons:
   1. The Clean Air Act requires an up-to-date, contemporary assessment and relying on an out-dated presumption conflicts with the very purpose of the residual risk analysis.  
   2. There is significant new information on the factors the EPA discussed in its old rulemaking that should influence its analysis today of what level of risk is currently "acceptable".  
   3. Scientific research has evolved dramatically since the EPA set that presumption.  There has been a vast increase in understanding of the relationship between the environment and public health, in particular, appreciation for the importance of assessing environmental hazards and exposures with respect to community health and as they are experienced by individuals who live in communities.  Commenter cites risk assessment studies and guidance, studies on children's exposure to toxics, and CDC reports as providing evidence of the EPA and other federal funded research and developments in health effects of chemicals.  
   4. The EPA's commitment to environmental justice must inform its consideration of what level of risk is "acceptable" as required by the 1994 Environmental Justice Executive Order and 2010 guidance to direct all federal agencies to take environmental justice into consideration.  The consideration of environmental justice should factor into the question of what level of risk is "acceptable" today.
   5. American values and policies have evolved to tolerate less health risk from industrial pollution. As pollution-control technology and industrial practices have evolved to be able to better protect human health, their evolution has also changed the "world in which we live" and with it, the public's views on what level of risk may be acceptable (or not). 
      
      The commenter contends that a lifetime cancer risk below the level of 100-in-1 million can no longer be presumed "safe" or "acceptable" in "the world in which we live" due to the dramatic evolution of science, technology, and social values that have occurred in recent decades.  Due to these changed circumstances, the EPA must reassess whether a level below 100-in - 1 million and closer to the "aspirational goal" of 1-in-1 million should be adopted as a more stringent, presumptive upper limit for what is considered "acceptable."  This is a question that the EPA cannot evade by assuming everything it did in the Benzene Rule will remain per se lawful for all time, all persons and communities, and all source categories.  Ignoring the substantial new information and changed circumstances since the EPA last considered that question is arbitrary and capricious.
      Commenter 98 stated that the EPA fails to give a reasoned explanation for not proposing a stronger standard for arsenic and cadmium to provide an ample margin of safety.  The commenter noted that the risk assessment number the EPA found is five times the level associated with public health concerns and that the fact that cost are "high" for the WESP technology is not sufficient reason for the EPA not to consider how much acute or cancer risk reduction would occur if the EPA were to require further emission reductions based on this technology.  Commenter 95 also stated that emissions of arsenic and cadmium contribute to the risks posed by secondary lead smelters, yet the EPA's proposal will not address these risks in a manner consistent with the CAA.  According to the commenter, "When considering the risks associated with MACT-allowable emissions, the MIR could be up to 200 in 1 million.  EPA nevertheless has not proposed sufficiently protective residual risk standards."
      Response: As an initial matter, we note that in 1990 Congress codified in section 112(f) (2)(B) of the CAA the approach we use for our residual risk analyses.  Under that approach, the 100 in a million cancer risk is not a bright line indicating that risk is "acceptable."   Rather, we consider this health metric in conjunction with a variety of health factors to determine whether the risk is acceptable. Where we conclude that the risk is not acceptable, we cannot and do not consider costs in requiring controls to bring risks down to an acceptable level. However, the analysis of whether risk is acceptable is not the endpoint. Once we determine that controls are sufficient to ensure that risk is acceptable, we again review the health metrics in conjunction with the costs of controls, technical feasibility, and other relevant factors, to determine whether additional controls should be required to provide an ample margin of safety.  
      EPA also does not accept that the language in the en banc Vinyl Chloride opinion regarding risks "acceptable in the world in which we live", 824 F. 2d at 1165, dictates any particular quantitative result based on societal preference  -  especially when the court, in using this language, was indicating that risk-based standards for hazardous air pollutants did not need to be risk-free.  Moreover, the commenter does not support its contention that people are now unwilling to accept a level of risk that was acceptable at the time the CAA was amended in 1990. Nor does the commenter support how science has evolved in a way that would undermine the statutorily codified framework for determining risk acceptability. We note that for purposes of the proposed and final rule, we performed a demographic analysis for the purpose of informing the public of what demographic groups could potentially be impacted by a given rulemaking, and that analysis is in the docket.   We also note that since risks from exposure to lead compounds are acceptable to the most susceptible subpopulation after controls under EPA's approach here, other less susceptible populations likewise will be protected from unacceptable levels of risk from lead exposure as well.
      Comment : Commenter 98 stated that the EPA must reduce risk to a TOSHI of 0.2 or below.  According to the commenter:

      EPA has determined that this source category's HAP emissions result in a TOSHI or hazard quotient as high as 3 based on allowable emissions (or 0.6 based on "actual" emissions).  In its discussion of whether the risk is "acceptable" and what reductions may be required to reach such a level, EPA did not discuss the high TOSHI at all.  EPA must address chronic non-cancer health effects in its analysis before finalizing this rule.
      
      In finding that a non-cancer TOSHI of 1.0 or less is not a human health concern, EPA has ignored its staff's scientific assessment and reversed its hazard index policy to align it with industry wishes.  In an internal memo from 2002, Residual Risk Program: Selection of Hazard Index Limits, EPA stated that the default HI limit for chronic non-cancer risks should be well under 1.0 for individual sources -- specifically, it should be 0.2.  The rationale for a maximum non-cancer HI of 0.2 expressed in the 2002 EPA memo states that a limit of 0.2 would allow an individual source to account for 20 percent of the contribution to total exposure in its vicinity.  An HI limit of 0.2 attempts to provide a de minimis fraction below which contributions are considered insignificant to total exposure while not allowing a single source to dominate the total exposures to similar noncarcinogens in its vicinity.
      
      EPA has not evaluated other nearby sources of HAPs, it has not considered the multipathway exposure from certain pollutants, and it has failed to consider the interaction of multiple health risks found for affected communities.  Therefore, EPA's analysis provides only one piece of the chronic non-cancer health risk.
      
      Failing to ensure that chronic non-cancer health risks do not exceed a TOSHI of 0.2 from this source category does not sufficiently protect local communities' health from cumulative exposure.  EPA must address and account for cumulative impacts and multiple contributors to risk.  It may not permit a single source covered by this rulemaking to consume the entire non-cancer risk safety factor.

      Response: The EPA disagrees with the commenter's notion that any TOSHI value greater than 0.2 should be considered unacceptable. We note that pollutant-specific reference concentrations (RfCs) are not absolute thresholds, but estimates of chronic inhalation exposures at or below which health effects would not be expected to occur, including in sensitive subgroups. We further note that these RfCs are developed using a health-protective approach (see uncertainty discussion in risk assessment document section 4.2), that TOSHI values of 1 or less are (like RfC levels) generally considered to carry no appreciable risk of adverse health effects and that there is generally no need to compound this protection by suggesting that any source category maximum TOSHI value would need to be at or below 0.2 before we would consider it to be acceptable.
      We further note that we generally draw no bright lines of acceptability regarding cancer or noncancer risks from source category HAP emissions, and that it is always important to consider the specific uncertainties of the emissions and health effects information regarding the source category in question when deciding exactly what level of cancer and noncancer risk should be considered acceptable. In addition, the source category-specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultaneously consider all potential health impacts -- chronic and acute, cancer and noncancer, and multipathway, -- along with their uncertainties, when determining the acceptable level of source category risk. Experience with source category rulemakings in the past tells us that this means that drawing bright lines for such decision-making is impossible. The Benzene NESHAP decision framework of 1989 acknowledged this; in today's world, such flexibility is even more imperative, because new information relevant to the question of risk acceptability is being developed all the time, and the accuracy and uncertainty of each piece of information must be considered in a weight-of-evidence approach for each decision. This relevant body of information is growing fast (and it will continue to grow faster and faster), necessitating a flexible weight-of-evidence approach that acknowledges both complexity and uncertainty in the simplest and most transparent way possible. While this challenge is formidable, it is nonetheless the goal of the EPA's RTR decision-making, and it is the goal of the risk assessment to provide the information to support the decision-making process. 
      In this case, the pollutant primarily driving the unacceptable risk is lead compounds, and control of lead compounds to meet the primary lead NAAQS reduces lead risk of air-borne lead emissions from this source category to an acceptable level.  See Section IV.A of the preamble. With regard to lead as well as to other HAP, as part of the second step ample margin of safety analysis, we did look for additional controls and process improvements that might further reduce risks in a cost-effective, technically feasible manner. In this case, we didn't find any additional cost-effective controls and ultimately concluded that the level of control that brought risks to an acceptable level was also the level of control that resulted in public health being protected with an ample margin of safety. See 76 FR at 29057-59.  Moreover, control of lead will effectively co-control all other metal HAP, see Secondary Lead Smelting-- Background Information for Promulgated Standards (EPA-453/R-95- 008b) at page 2-19, a conclusion unchallenged in the record for this rulemaking.  
      Finally, we note that the commenter's source for its statement that default limits HI should or must be established at 0.2 rest on an internal EPA staff memo (from 2002) which was never adopted as agency policy (and never reviewed by the public or by any peer review body) and consequently carries no precedential weight.  
      Comment:  Commenter 98 stated that the EPA did not appropriately address issues of socioeconomic disparity in health risks from this source category.   While supporting the EPA's effort to gather demographic data and to incorporate environmental justice into their consideration of what level of public health risk is "acceptable" or not under section 112(f)(2) the commenter stated that the EPA should use these data to protect families from unacceptable risk.  A level of risk that might otherwise be "acceptable" becomes unacceptable when, as here, lower income individuals are disproportionately affected.
      Response:  As explained in response at pages 64 above, there is higher incremental IQ loss at low blood lead levels and a standard that would protect against incremental IQ loss at low blood levels would also protect populations with higher blood lead levels.  Moreover, the lead primary NAAQS targets protection at the most susceptible subpopulation for the most sensitive effect: children living near a lead source with low blood lead levels who are exposed to air-borne lead at the level of the NAAQS.  By assuring that risks to this most susceptible subpopulation are reduced to acceptable levels, subpopulations who are less susceptible are also necessarily protected from unacceptable risk.  As EPA explained in the lead NAAQS proceeding, 

      "EPA agrees with commenters that on average in the U.S., minority and low-income children have higher blood Pb levels than the general population, as shown by the NHANES information referenced in section II.A.2.b of the preamble and described in section II.B.1.a of the proposal (e.g., http://www.epa.gov/envirohealth/children/body_burdens/b1-table.htm). EPA also agrees that these higher average blood Pb levels are indicative of these subpopulations being sensitive with regard to total Pb exposures. However, EPA notes that this evidence does not provide information regarding a potential for increased sensitivity to air-related Pb exposure. Due to the nonlinear dose-response relationship between IQ loss and blood Pb, EPA concludes that the population with lower blood Pb levels from both air and nonair sources would be expected to have a greater incremental sensitivity to Pb impacts on IQ (i.e., greater risk of IQ loss per incremental unit of blood Pb). Thus, a standard that is selected to provide protection from the incremental amount of blood Pb associated with air-related Pb to populations with lower total blood Pb levels will also necessarily provide protection from the air-related Pb associated with exposures at the level of the standard to populations with higher total blood Pb levels. As explained in section II.C.3.b of the preamble, the air-related IQ loss framework focuses on children exposed at the level of the standard, children living near air sources of Pb who are likely to be most highly exposed. In concentrating on this highly exposed group of children, EPA has focused on providing sufficient protection for the appropriate subpopulation for this review."

Pb NAAQS, Response to Comment Document p. 7, available at http://epa.gov/ttn/naaqs/standards/pb/s_pb_cr_rc.html. 
      To reiterate, since the revisions to this standard will protect the most sensitive subpopulations, it will also protect all other population subgroups and demographic groups.
      
      Comment:  Commenter 98 stated that the EPA has failed to justify not requiring the reduction of acute health risk below 1.  According to the commenter:

      EPA recognizes that the worst-case acute hazard quotient is 30.  Nine existing facilities have a worst-case hazard quotient above 1.  EPA has recognized that a hazard quotient of 1 or above indicates the potential for acute risk.  EPA"s proposal states that the controls it is proposing for arsenic emissions will reduce the acute HQ values to 5 or below.
      
      However, this is five times the hazard quotient that may be associated with acute health effects.  EPA fails to address or explain why it is not requiring additional emissions reductions of arsenic to ensure that the acute risk is reduced to a level below 1.

      Response:  The commenter is correct that post-control, there would be one facility with an estimated acute risk of 5 in the risk assessment supporting the proposed rule.  See Appendix 5 to the risk assessment for the proposed rule at page 4, docket ID EPA-HQ-OAR-2011-0344-0036.  This does not mean that the risk is unacceptable.  We first note that there would be only two facilities in the source category with an estimated worst-case acute risk greater than 1 post-control.  In addition, the EPA notes that acute risk of 5 post-control is based on a reference exposure level (REL) value, which is not a concentration at which health effects are expected to be observed.  That is, the REL is defined as "the concentration level at or below which no adverse health effects are anticipated for a specified exposure duration" (see section 2.6.2 of the draft risk assessment document in the docket for this rulemaking).  Moreover, we note that the acute risk assessment is a worst case assessment.  For example, the acute assessment assumes worst-case meteorology, peak emissions and an individual being located at the site of maximum concentration for an hour.  Taken together, the EPA does not believe that in all RTR reviews, HQ values must be less than or equal to 1.  Rather, the EPA finds that acute risks must be judged on a case by case basis in the context of all the available health evidence and risk analyses. Here, for the reasons just given, EPA considers the risk from acute exposure to be acceptable given the generally low HI values (that are based on worst case assumptions).
      Comment:  Commenter 98 stated that the EPA's proposal fails to provide an ample margin of safety to protect public health from lead emissions.  The commenter stated that the EPA's proposal has not met the legal standard of section 112(f)(2) as it merely replicates the lead NAAQS.  The commenter contends that the Clean Air Act sets different tests for the NAAQS and NESHAP rules and that the EPA cannot substitute one for the other.
      The commenter noted that the plain text of section 112(f)(2) uses the term "ample margin of safety", while the lead NAAQS is a standard that allows an "adequate margin of safety."  Citing the definitions of the words "ample" and "adequate", the commenter contends that using the term "ample" demonstrates that the EPA is required to do more than just set an "adequate" or bare minimum level of protection.
      The commenter further noted that the lead NAAQS "merely aims to prevent a loss above 2 IQ points at the mean population level of exposure, even though in EPA's staff's view, a loss below that, of 1-2 IQ points, could be considered `highly significant from a public health perspective.'" The commenter also stated that section 112(f)(2) requires a different focus than section 109.  More specifically, the NAAQS's focus is protecting the national population as a group, whereas under section 112(f)(2), the EPA is required to protect the  people living near the sources in the category.
      The commenter noted that in setting the NAAQS, the EPA recognized that there would be greater impacts to the more exposed individuals.  The commenter contends that children living near secondary lead smelters are not only a population with increased susceptibility, but they also face elevated levels of exposure because they live near secondary lead smelters. The EPA's staff paper for the lead NAAQS shows that children living near the lead smelting facilities would still be subject to an IQ loss as high as 3.9 (at the median) to 7.3 (at the 95[th] percentile), even if the EPA had set the NAAQS at 0.02 instead of 0.15 ug/m[3].  The commenter stated that this shows that an ambient air concentration of 0.02 ug/m[3] would not achieve an acceptable level of risk for children living near a secondary lead smelter, let alone provide an ample margin of safety. The commenter stated that the EPA must set a residual risk standard that prevents the local ambient lead concentration from exceeding the CHPAC-recommended limit of 0.02 ug/m[3] as a monthly average. 
      The commenter contends that in choosing the lead NAAQS, the EPA "chose to allow an IQ point loss for the children...living near lead smelting facilities, above the 1 to 2 points that is considered to be "highly significant from a public health perspective," and above the 2 points that is considered to allow an "adequate margin of safety" for the national population level of exposed children."  Therefore, replicating the NAAQS in this rulemaking fails the section 112(f)(2) test to provide an ample margin of safety to communities near secondary lead smelters.
      The commenter further stated that replicating the lead NAAQS as a standard is also problematic because it ignores cumulative, long-term impact to individuals from prior lead emissions.  Ambient lead concentrations are not the only relevant thing because it does not account for reservoirs of lead in soil and elsewhere.  The commenter contends that children can face higher levels of exposure from dust and soil than from inhaling air.
      The commenter claimed that "EPA says the standard provides an ample margin of safety because EPA has not identified any further feasible and cost-effective controls beyond the wet electrostatic precipitator which it deems too expensive."  The commenter stated that the EPA provides no explanation as to how the fact that it was unable to identify less expensive control options means the ample margin of safety requirement is met.  The commenter further noted that the EPA, in its own analysis, identified other facilities that are using HEPA filters in addition to baghouses to achieve lower concentrations of lead.
      The commenter noted that the ample margin of safety determination is "a decision about whether to set the standard lower than the acceptable risk, taking feasibility into account."  The commenter further noted that most facilities achieve emission levels well below those proposed by the EPA and that the data demonstrates that the risks can be reduced further beyond the EPA's proposed standard, taking feasibility and cost into account.
      Response: Most of this comment is addressed at page 64 above. We add that in order to assess multipathway risks associated with emissions of lead, the EPA compared modeled rolling three month average lead concentrations estimated from emissions to the NAAQS for lead. As noted above, we believe that this is a reasonable approach given that the NAAQS is a health based standard set to protect the public health, including the health of sensitive sub-populations with an adequate margin of safety. Moreover, the NAAQS for lead specifically is targeted to provide requisite protection with an adequate margin of safety to prevent neurologic effects to children with low blood lead levels living near a lead source and exposed at the level of the NAAQS.  While we conclude that the NAAQS presents an acceptable level of risk from lead in ambient air, and are requiring controls to ensure that the NAAQS is not exceeded, as part of our "ample margin of safety" analysis, we examined whether there were additional cost effective controls available to further protect public health including monitoring at a level below 0.15 ug/m[3]. For the reasons explained elsewhere in this notice and other supporting documents available in the docket, we have determined that there are no additional cost effective, technically feasible controls that would provide further risk reductions. 
      In addition, the commenter states:  "EPA's staff paper for the lead NAAQS shows that children living near the lead smelting facilities would still be subject to an IQ loss as high as 3.9 (at the median) to 7.3 (at the 95th percentile), even if the EPA had set the NAAQS at 0.02 instead of 0.15 ug/m3."  As noted above, this comment may be in error.  The Staff Paper and notice of final rulemaking (73 FR at 66982) indicates a median air-related IQ loss estimated to be less than 3.7 (using the higher confidence loglinear C-R function, and less than (1.2-5.1) via the other 2 functions) for children living within 1.5 km of primary smelters.   Moreover, as noted in the earlier comment response, EPA did not rely on the risk assessment as the primary basis for its revisions to the primary lead NAAQS.
      With respect to the California benchmark for protecting children, the EPA has a hierarchy of appropriate health benchmark values.  In general, this hierarchy places greater weight on EPA derived health benchmarks than those from other agencies (http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf). For the reasons provided above, we believe that the lead NAAQS establishes an appropriate benchmark for addressing acceptability of risk and we therefore disagree with the commenter that we should instead use an ambient concentration of 0.02 ug/m[3] based on a one month average.
      Comment:  Commenter 98 cited the following from the preamble to the proposed rule regarding environmental risk from this source category for HAPs other than lead:

      With respect to potential for adverse environmental effects from non PB-HAP, we note that there is a lack of information about specific adverse environmental effects occurring at a given concentration of HAP for this source category.  However, given that all chronic non-cancer HQ values considering actual emissions are less than 1 using human health reference values, we believe that it is unlikely that adverse environmental effects would occur at the actual HAP concentrations estimated in our human health risk assessment.

      The commenter noted that the EPA provides no explanation as to why its conclusion regarding environmental risk from non-PB HAPs is true.  The commenter further noted that the EPA has recognized the need to look at emissions above the actual level for human health.  The commenter stated that the EPA must perform an ecological risk assessment and may not simply rely on the human health assessment without a reasoned explanation for doing so.  
      The commenter noted that chemicals that are persistent in the environment or bioaccumulate in living tissue will remain or increase over time.  Therefore, additional exposure would be added to a background that is likely already unsafe for wildlife and other environmental resources.  Lack of human health risks from inhalation does not mean that the EPA can conclude that there would be no effects to wildlife or other natural resources either form inhalation or air deposition of HAP emissions, exacerbated by persistence and bioaccumulation.
      Response: First, the secondary NAAQS for lead, which is requisite to protect public welfare from known or anticipated adverse effects, is identical to the primary lead NAAQS.  Thus, in meeting the controls for lead (which also result in co-control of all other non-mercury HAP metals) emissions will be controlled to levels less than allowed by the secondary lead NAAQS.  Second, EPA is to adopt more stringent standards directed to adverse environmental effects only upon taking into consideration "costs, energy, safety, and other relevant factors".  As discussed as part of the ample margin of safety analysis, EPA has determined that these factors militate against adopting any further controls (and reached a similar conclusion based on similar factors in its section 112 (d)(6) analysis) and this same reasoning applies with respect to adopting further controls to prevent adverse environmental effects.  Moreover, without specific information about how, and at what concentration a given HAP affects a given ecological receptor, the EPA is unaware of how it could have performed a separate ecological risk assessment.  As noted by the commenter and in the risk assessment document, we generally conclude that for non PB-HAP, if all chronic non-cancer HQ values are less than 1 using human health reference values, than we believe that it is unlikely that adverse environmental effects would occur.  However, we disagree with the commenter that we do not provide a rationale for this judgment.  The risk assessment states in section 2.5:
      Human health dose-response reference values are generally derived from studies conducted on laboratory animals (such as rodents) and developed with the inclusions of uncertainty factors that could be as high as 3000.  As a result, these human reference values are often significantly lower than the level expected to cause an adverse effect in an exposed rodent. It should be noted that there is a scarcity of data on the direct atmospheric impact of these HAP on other receptors, such as plants, birds, and wildlife.  Thus, if the maximum inhalation hazard in an ecosystem is below the level of concern for humans (i.e., is below the human health reference value which is itself a lower reference value than would be expected for an ecologic effect), we have generally concluded that mammalian receptors should be at no risk of adverse effects due to inhalation exposures from non PB-HAP, and have assurance that other ecological receptors are also not at any significant risk from direct atmospheric impact.  
      
      With respect to the potential for ecological risk associated with PB-HAP, we note that our multipathway analysis indicated that all chronic non-cancer HQ values were less than 1 using human health reference values.  Thus, we believe that it is unlikely that adverse environmental effects would occur considering actual emissions.  We further believe this is a reasonable interpretation of the multipathway analysis given a lack of information on the effects of PB-HAP on specific ecological receptors.  
      Finally, we agree with the commenter that the potential for ecological effects should be noted when considering MACT-allowable emissions.  Thus, when HQ values are greater than 1 considering MACT allowable emissions, we note that there is at least some potential for ecological effects. 
Emissions Used
      
      Comment:  Two commenters (90, 96) stated that the EPA's risk review is invalid because it fails to consider the reduction in dioxin and arsenic risks that would occur with the use of the proposed additional controls.  The commenters compared the dioxin concentrations and risks to background dioxin concentrations and risks for the entire US populations and concluded that dioxin emissions from secondary lead smelters produce a contribution to the environment that is "not distinguishable from background concentrations."  The commenters contend that additional controls on dioxin emissions from this source category will result in less than a 1% reduction in an exposed individual's risk.
      With respect to arsenic, the commenters stated that the average background levels of arsenic in urban air (20 to 30 ng/m[3]) result in inhalation risks between 35 and 50-in-1 million, similar to the MIR risk that the EPA yielded for the secondary lead smelters.  The commenter contends that the EPA should demonstrate how arsenic emissions from the secondary lead smelting industry would affect the extant risk from arsenic.
      Response: The EPA disagrees with the commenters that it did not consider reductions in risk after the proposed controls.  Section 3.3 of the draft risk assessment document is titled: "Post-control risk characterization" and it describes the estimated risks after potential controls are in place.  Moreover, we note that the risk estimates calculated by the EPA are those associated with emissions from the source category.  Similarly, risk reductions estimated after considering the proposed controls are based on estimated reductions in emissions from the source category.  Thus, the estimated risk reductions described in the draft risk assessment and preamble are independent of the background levels for a given HAP.
      Comment:  Commenter 98 stated that the EPA's failure to recalculate the risk assessment after changing its fugitive dust estimates is problematic given that the EPA's modeling shows that fugitive emissions are the largest contributor to risks from this source category.  The commenter further stated that because the EPA failed to "test or provide a reliable accounting for its measure of fugitive dust emissions...", it has underestimated risk and should compensate by setting a stronger standard.
      Response: We have updated the fugitive emissions based on corrections received in public comments. However, we disagree that the methodology used for calculating fugitive emissions are underestimating emissions or risk and require a stronger standard. The estimates provided by some facilities were unrealistically low and we developed the methodology to better account for fugitive emission levels as described in the proposal. See 76 FR at 28038. However, the estimates of fugitive emissions which EPA developed were overstated due to an error in the emission estimate for Exide Frisco, which was used to calculate estimates for the other facilities. The recalculated (and reduced) fugitive emission estimates led to a slight decrease in the risks due to fugitive emissions; however, we disagree that the methodology was fundamentally flawed in a way that would yield an underestimate of risk. 
      Comment:  Commenter 98 stated that failing to include MACT-allowable emissions in the multipathway risk assessment is a "glaring inconsistency in the EPA's analysis that is arbitrary and capricious.  The commenter contends that relying on actual emissions does not sufficiently protect populations living near the smelters, which have a range of emissions and may exceed levels allowed by the MACT standard.
      Response: We did not have detailed enough information to perform a multipathway risk assessment considering MACT allowable emissions.  In fact, for dioxins and furans as well as for mercury there was no MACT standard in the 1997 NESHAP and thus, we would be unable to calculate MACT allowable emissions for these pollutants.  However, as noted in the proposal preamble, the proposed limit for dioxins and furans and mercury would lower multipathway risk somewhat and would also ensure that multipathway risks associated with dioxins and furans and mercury did not increase. See 76 FR at 29064.
      Comment:  Three commenters (80, 90, 91) noted that the docket did not contain the data inputs to the AERMOD and Human Exposure Model (HEM-3) and that they were thus unable to properly comment on the methods or results of air dispersion and risk modeling.  Commenter 90 supplied a list of technical documents not available that included stack test reports, survey responses, and underlying data sets. 
      Response:  The EPA disagrees with the commenters.  The docket contains model input information that could be used to replicate the HEM-3 results.  This includes emissions and emissions location information. Disks with the technical documents mentioned by the commenters were sent to the Docket Center; however, CD availability was not posted because some of the test reports included in the disks contained confidential business information. 
      
      Baseline Emissions Estimates
Fugitive Emissions Estimates

      Comment:  Commenters 90, 91, and 96 stated that the EPA's factoring approach for estimating fugitive emissions is methodologically unsound. The EPA classified each facility as Level 1, Level 2, or Level 3 based on the degree of fugitive emissions control implemented at each facility.  The commenters claimed that the EPA failed to take into account the fact that Exide Frisco itself is a Level 2 facility, meaning that the EPA effectively used the "wrong common denominator" for each facility.  This resulted in overstating emissions from Level 3 facilities and understating emissions from Level 1 and Level 2 facilities.  Commenter 80 stated that there is no description of the method the EPA used to determine scaling factors, nor how the calculation was verified.
      Response:  Although the Exide Frisco facility was classified as a level 2 facility, the enclosures at the Frisco facility were limited to the material handling area.  For this reason, the facility had many similarities to the facilities classified as level 1.  In an attempt not to overstate or understate emissions from any facilities by a large amount, a decision was made to perform the calculations as described in the Development of the RTR Emissions Dataset for the Secondary Lead Smelting Source Category document available in the docket.  We also note that the scaling factors were partly based on confidential business information that was not appropriate to publish.
      Comment:  Commenters 80 and 94 stated that the fugitive emissions estimate for the Exide Forest City facility is over an order of magnitude higher than the NEI estimate of 0.06 tons per year and that such an overestimation calls into question the reliability of the EPA's estimates.
      Response:  Because of their nature, fugitive emissions are not readily measurable. The National Emission Inventory (NEI) estimates for this source category were inconsistent and unreliable for many facilities. The estimates used for the Exide Forest City facility were developed using the same methodology that was used for the other facilities in this source category.  We note that although ambient lead data is not available near the Exide Forest City facility, a comparison of modeled and actual ambient lead concentrations for those facilities that did have ambient monitors located nearby indicated that our estimates of fugitive emissions were reasonable. See Residual Risk Assessment for the Secondary Lead Smelting Source Category and Summary of the Ambient Lead Monitoring Data near Secondary Lead Smelting Facilities, available in docket ID EPA-HQ-OAR-2011-0344.
      Comment:  Commenter 93 stated that the use of both ambient air data and TRI emissions data to estimate fugitive emissions at the East Penn Manufacturing facility is inappropriate since East Penn operates six lead-acid battery manufacturing facilities in addition to its secondary lead smelting sources.  The commenter stated that considering that East Penn has managed a reduction in emissions of HAP to levels at or below the numerical limits of all applicable standards while operating several lead-acid battery manufacturing sources in addition to its secondary lead smelting sources, the EPA's assertion that fugitive dust emissions are the largest contributor to the risk due to lead emissions is overstated.
      Response:   The absolute amount of emissions from fugitive sources is not directly measurable and therefore can only be estimated.  We acknowledge that the fugitive emissions from the secondary lead manufacturing process at East Penn may be lower than the estimates used for the development of this rule; this has been taken into account in our revised estimates.  We note that the East Penn facility is a well controlled facility that utilizes total enclosure to control fugitive emissions from the majority of the manufacturing process.  It is a facility that has demonstrated the level of control we believe is necessary to reduce fugitive lead emissions from this source category to an acceptable level. We performed dispersion modeling based on emissions from the East Penn facility. Our modeling did not include emissions from nearby facilities that are not within the same contiguous property boundary. The dispersion modeling showed that emissions from East Penn's secondary lead smelting operations yield ambient concentrations well below the NAAQS. See Table 1 in the preamble for the final rule, showing that East Penn's emissions are about 1/10[th] the NAAQS. 
      Comment:  Commenter 98 stated that it is inappropriate to call the EPA's fugitive emissions estimates "actual".  The commenter claims that the EPA should measure fugitive dust emissions, such as through ambient monitoring.  If estimates are used, the commenter stated that the EPA should use actual ambient monitoring data and conservative factors to make up for uncertainty created by the failure to measure directly.
      Response:  The nature of future emissions makes them impossible to directly measure.  Based on a comparison of modeled ambient lead concentrations with actual ambient monitoring data near the secondary lead smelting facilities, we believe that our estimates of fugitive emissions for this source category are reasonable.  Therefore, we disagree that it is not appropriate to regard these estimates as "actual" emissions.  (In any case, this comment is somewhat semantic.  Whether referred to as actual or estimated actual emissions, EPA has explained above, and in detail at 76 FR 29038, why its estimates for fugitive emissions are reasonable.)
Stack Emissions Estimates
	Comment: Commenter 98 stated that the EPA should not refer to its emissions estimates as "actual" emissions for the following reasons: (1) the EPA failed to collect emission test data for all stack emissions or all pollutants; and (2) the EPA failed to account for potential malfunctions and exceedances of the standard.
Response:  We disagree that the emission estimates should not be referred to as "actual" emissions.  The emissions estimates were calculated based on the best available stack test data in all instances where stack test data was available.  If stack tests for a certain source were not available, we assigned emissions to the source based on the closest match for a similar source for which test data was available. 
We disagree with the commenter that emissions that exceed standards and are violations, whether or not caused by malfunction events, should be considered as part of the risk analysis. The purpose of the risk review is to evaluate whether the emission limits -- the "standards promulgated pursuant to subsection (d)" not the non-compliance with those standards (section 112 (f)(2)(A) -- should be made more stringent to reduce the risk posed after compliance with the underlying MACT standard. To the extent that a source is violating the underlying MACT standard, no tightening of the emission standard under the residual risk rule will avoid or mitigate against such violations. In other words, a source that is violating the MACT emissions standard promulgated under section 112(d) would not be any more likely to be able to avoid such violations and comply with a different presumably more stringent standard promulgated under section 112(f). Such events are violations and subject to enforcement by the EPA, the States or citizens and an action for injunctive relief is the most effective means to address violations whether or not they are caused by malfunctions if an emissions event poses a significant health or environmental risk.
Although we disagree that emissions that result in a violation should be considered as part of the risk review, we note that we believe malfunction events in this source category do not contribute significantly to cancer or chronic noncancer risks for the source category in this rulemaking because malfunction events in this source category are inherently short-term and infrequent relative to annual operations and emissions. The commenter did not supply any data to the contrary.
Furthermore, the conservative estimates built into the acute risk assessment are sufficient to gauge worst-case potential acute health effects. The conservative estimates built in to the assessment include worst-case meteorology, emissions at ten times the maximum peak emission rate from all point sources simultaneously, and the sum of the maximum impact of each emission source, regardless of receptor location. Thus, even if we were to consider emissions that are in violation of the standard, we do not believe that they would result in any different level of control than we are promulgating here.
      Compliance Timeline
      Comment:  Commenters 90 and 96 stated that section 112(i)(3)(A) establishes 3 years for compliance for "any" section 112 standards, including those established under Section 112(f).  The commenter cites the following excerpt from CAA §112 (i):
      
      After the effective date of any emissions standard, limitation or regulation promulgated under this section and applicable to a source, no person may operate such source in violation of such standard, limitation or regulation except, in the case of an existing source, the Administrator shall establish a compliance date or dates for each category or subcategory of existing sources, which shall provide for compliance as expeditiously as practicable, but in no event later than 3 years after the effective date of such standard, except as provided in subparagraph (B) and paragraphs (4) through (8).

The commenters contend that the EPA did not address CAA § 112(i)'s applicability to the proposed rule.  Instead, the EPA relied on 40 C.F.R. §63.6(f)(4)(ii), which states that "the owner or operatory of an existing source unable to comply with a relevant standard established ... pursuant to section 112(f) ... may request that the Administrator grant an extension allowing the source up to 2 years after the standard's effective date to comply with the standard."
The commenters stated that CAA § 112(i)'s application is mandatory.  The commenters noted that Congress used the word "any" in defining CAA § 112(i)(3)(A)'s applicability.  According to the commenter, "A broad construction of CAA § 112(i)(3)(A) mandates that this section, and the Administrator's discretion for extension, apply to all regulations under CAA §112, including standards promulgated under subsections (d) or (f).
The commenters further noted that 40 C.F.R. § 63.6(i)(4)(ii) applies only to standards set pursuant to section 112(f) and that while the EPA's proposed revised emission standard for lead is a section 112(f) standard, the design and work practice standards for fugitive emissions are also section 112(d)(6) standards, and dioxins and furans would be wholly new standards set pursuant to section 112(d)(3).
      Response: Section 112(i)(3) establishes the compliance timeframe for any standard issued under section 112 for existing sources and provides that the compliance date shall be as expeditious as practicable but no later than 3 years following the effective date of the standard. Section 112(f)(4), however, expressly provides more specific requirements for standards issued under section 112(f) and thus for section 112(f) standards those more specific  requirements (i.e. a specific requirement for section 112 (f) standards) govern in place of the more general compliance date requirements in section 112(i)(3). Specifically, section 112(f)(4) provides that a source cannot emit an air pollutant in violation of a standard issued under subsection (f) except that the standard will not apply until 90 days after its effective date. It also provides that the Administrator may grant a waiver for a period of up to 2 years from the effective date if necessary for the installation of controls and if measures will be taken in the interim to ensure public health is protected from imminent endangerment.
      As stated in the technical documents supporting the proposed rule, we do not believe that additional controls will be required for facilities to meet the new dioxin and furan standards. However, the two year compliance date is appropriate to allow facilities the time needed to perform testing to determine whether they will need to modify existing control devices and complete such modifications, if necessary, to comply with the standard for  dioxins and THC.  See also 76 FR at 29064/1 explaining why it is possible for EPA to find at this time that sources need two years to comply with the risk-based standards for metal HAP.
      Comment:  Commenters 90 and 96 stated that a two year compliance schedule is insufficient and unrealistic based on the required controls set forth in the proposed RTR, particularly the total enclosures.  The commenters stated that for facilities that do not currently contain total enclosures, designs must consider efficient movement of materials between processing steps and the indoor work environment.  The construction must also be carefully staged around the process equipment and it is likely that the large enclosures could only be constructed during scheduled periodic maintenance downtimes which are scheduled at least six months apart.
      Response: As just stated, CAA section 112(f)(4) expressly provides specific requirements for compliance dates for standards issued under section 112(f). Specifically, section 112(f)(4) provides that a source cannot emit an air pollutant in violation of a standard issued under subsection (f) except that the standard will not apply until 90 days after its effective date. It also provides that the Administrator may grant a waiver for a period of up to 2 years from the effective date if necessary for the installation of controls and if measures will be taken in the interim to ensure public health is protected from imminent endangerment. Two years has been provided for compliance with the rule given that the two year period is necessary to install controls.
      Comment:  Commenters 90 and 96 stated that the facilities are facing obligations to attain the 2008 lead NAAQS and require time to determine the degree to which these obligations overlap with the NESHAP implementation in order to develop appropriate design and construction plans.
      Response: CAA section 112(f)(4) expressly provides specific requirements for standards issued under section 112(f). Specifically, section 112(f)(4) provides that a source cannot emit an air pollutant in violation of a standard issued under subsection (f) except that the standard will not apply until 90 days after its effective date. It also provides that the Administrator may grant a waiver for a period of up to 2 years from the effective date if necessary for the installation of controls and if measures will be taken in the interim to ensure public health is protected from imminent endangerment. Two years has been provided for compliance with the rule given that the two year period is necessary to install controls.
      Comment:  Commenters 90 and 96 stated that the EPA is engaging in numerous actions that affect other industry sources (e.g., Boiler MACT, Utility MACT, other RTR actions) that will increase the cost of compliance by increasing the demand for construction services.
      Response:  We believe that it is unlikely that any of the mentioned actions will impact the availability of the necessary services to the secondary lead smelting facilities.  The commenter provides no evidence to the contrary. Nor does the comment provide details as to how these other actions impact the compliance dates set forth in the CAA for section 112(f) standards.
      Comment:  Commenters 90 and 96 stated that it is possible that the EPA could take the position that for an area to be designated as attaining the lead NAAQS, the monitored ambient lead levels for the three years before November 2015 must be below 0.15 ug/m[3] on a three-month rolling average.  If ambient lead levels must be below the NAAQS by November 2012, then a final rule promulgated in early 2012 would not allow time for NESHAP control measures implemented by March 2014, to provide for timely NAAQS attainment.
      The commenter further stated that "an EPA position that states must demonstrate attainment of the NAAQS based on the three-month average over a three year period before the NAAQS attainment deadline would be contrary to the Clean Air Act."  The commenter asked that the EPA clarify its position with respect to the NAAQS-NESHAP compliance timeline and state that the NAAQS measures do not need to be implemented to reach the ambient standard until the attainment year.
      Response: The CAA clearly presents the compliance dates for standards promulgated under section 112(f). We also note as a point of information that the CAA requires areas to attain the various NAAQS as expeditiously as practicable, but no later than specified dates. For the 2008 lead NAAQS, areas are required to attain the standard as expeditiously as practicable, but no later than December 31, 2015. The Act not only contemplates but requires, if practicable, for areas to attain the 2008 lead NAAQS earlier than December 31, 2015.   Furthermore, no action EPA is taking in this rulemaking changes, modifies, or otherwise bears upon legal obligations to attain the lead NAAQS.
      Comment: Commenter 98 stated that the two year compliance schedule for the proposed RTR is unlawful.  The commenter stated that the two year compliance date violates the plain text of Sections 112(f)(3)-(4) which requires immediate compliance for new sources and a 90-day compliance date for existing sources.  The commenter stated that under section 112(f), individual facilities may file an application for a 2-year extension of compliance.  The EPA must then evaluate each request on a case-by-case basis.  The commenter stated that the EPA is not authorized to grant a Section 112(f)(4) "waiver" to a category of facilities without going through the case-by-case process  -  application, submission of specific information, participation by affected communities -- set out in EPA's implementing regulation.  The commenter stated that the EPA's proposal also violates section 112(f)(4) because the EPA's record included no evidence that statutory factors are met.  The commenter stated that the document entitled "Estimated Time Needed to Achieve Compliance" was not available in the publically viewable docket when checked by the commenter on July 12 and July 25, 2011.  The commenter stated that the record does not state how many sources need two years to comply, or whether faster compliance may be possible for sources like Quemetco, Inc. in City of Industry, CA that have already reduced their emissions to low levels.  The commenter further stated that even if the document provided information that any facility may need additional time, the second statutory factor bars the compliance delay proposed by the EPA because there is "no evidence in the record that the necessary "steps" will be taken during the additional two years "to assure that the health of persons will be protected from imminent endangerment."  The commenter stated that even if the compliance delay were justifiable for existing sources, extending the delay for new sources violates the plain text of the statute.  The commenter further stated that the EPA has already delayed satisfying its legal duties by failing to begin this rulemaking until 2011, and that the EPA has no lawful justification to delay the compliance date any longer.
      Response: EPA is of course aware of the requirements of section 112 (f)(3) and (4).  See 76 FR at 29064/1.  EPA is not ignoring  the requirements of this provision.  Rather, as documented in the memorandum  Estimated Time Needed to Achieve Compliance with the Proposed Revision to the MACT standard for Secondary Lead Smelters, EPA has made case-by-case findings for each existing source as to the amount of time required to comply with the risk based stack and fugitive emission standards for metal HAP.  EPA does not interpret section 63.6 (i)(4)(ii) of its regulations to mandate individual applications when all of the necessary information is already before EPA and EPA applies that information in an individualized, case-by-case manner, as done here.  Moreover, section 112 (f)(4)(B) is a direct grant of authority which can be implemented not just by regulation but by other EPA action, as done here.  As documented in the memorandum cited above, the existing sources discussed in the memorandum will need to undertake such improvements as construction of enclosures, and replacement of baghouses (with such attendant interim steps as obtaining capital, purchase and delivery of equipment, installation of equipment, and shakedown operation).  These activities simply cannot be accomplished in 90 days, and two years is a reasonable amount of time to carry them out.
      The statute likewise contains the requirement that EPA must find that "steps will be taken during the period of the waiver to assure that the health of persons will be protected from imminent endangerment" in order to extend the compliance date.  We note first that EPA does not believe that any unacceptable risk under section 112 (f) automatically equates to an "imminent endangerment", given that Congress authorized extensions of the compliance date.  We note further that existing secondary lead sources are already controlled to some degree, and will necessarily make further reductions of their emissions as they implement steps toward full compliance.  For example, fugitive emissions will be reduced as total enclosures are constructed; fugitive emissions will also be reduced as work practices are phased in.  Emissions will also be reduced during the pre-compliance period as sources upgrade baghouses and develop means of better maintaining them.   Under these circumstances, the EPA believes that steps will indeed be taken in the period before full compliance to reduce emissions and prevent an imminent endangerment. 
      Finally, the commenter correctly points out that no extension of time for new sources is permissible under the statute.  The compliance date for new sources to meet the section 112 (f)(2) standards is consequently are immediately subject to the standard.  
      Performance Testing
Testing Frequency

	Comment: Commenters 80 and 86 stated that language in § 63.543(4) implies that testing must be done on a monthly basis while § 63.543(5)(f) makes it clear that testing must be done on an annual basis; the commenter asks for clarification.  Commenters 90 and 96 stated that their understanding is that testing is required on an annual basis while the average emissions are calculated monthly based on the most recent annual stack tests; the commenters ask that the EPA confirm that this is the intent of the proposed rule.
      Response:  The commenters are correct in their understanding that testing is required on an annual basis while the average emissions are calculated monthly based on the most recent annual stack tests.
      
Continuous Emissions Monitoring Systems (CEMS)
      Comment:  Commenter 84 recommended that the EPA require enhanced monitoring systems for lead on both existing and new secondary lead smelting facilities.  The commenter noted that congress mandated the EPA in the CAA to use enhanced monitoring systems when available.  The commenter further contends that direct measurement of lead and other HAP metals is essential for the EPA to comply with the intent of the CAA and to evaluate residual risk and improvements in control.  The commenter noted that new proven, commercial monitoring technology for continuous measurement of lead and other HAP metals including mercury is available.
      Commenter 81 stated that the most significant and relevant observation impacting this proposed rule is that there appears to be no threshold for lead exposure below which no health effects are observed.  The commenter contends that timely feedback regarding emissions is therefore particularly important because of the potential of fumigation from relatively low stacks and the potential for secondary lead smelting facilities to produce significant dose exposures over short time periods.  The commenter stated that significant advances in continuous metals monitoring technology have been made since the last NESHAP and provides evidence that near-real-time monitoring of lead and other metal HAP is commercially available.
      Commenter 81 stated that installation of a multi-metal CEMS would eliminate the EPA concerns over the effectiveness of baghouses in capturing mercury and would eliminate the need for a BLDS as well as the need to measure mercury content in scrap metals.  The commenter further stated that installation of a multi-metal CEMS would alleviate concerns over possible arsenic emissions.  The commenter also suggested that if the EPA does not require CEMS for stacks, they should require at least two ambient near-real-time lead monitors.
      In response to the EPA's stated concerns about the costs associated with lead CEMS, commenter 81 stated that "there are costs associated with no action" and that "the real problem is not that a number of stacks might require CEMS, but that there are too many low level stacks contributing to fumigation events in the local neighborhoods."  The commenter suggested that one potential strategy would be to direct these low level stacks to a common stack that could then be monitored with a single CEMS.  The commenter contends that "most secondary lead smelters are relatively small...", so that the cost to duct emissions to a common stack "should not be too high, particularly in comparison to the cost of monitoring all stacks individually."
      Commenter 81 stated that the lack of a performance specification for a lead CEMS is not a justifiable reason for not requiring them.  The commenter noted that the lack of a published performance specification did not prevent the EPA from requiring mercury CEMS or HCl CEMS for coal fired power plants.  The commenter further noted that the performance specification and QA procedure for multi-metal CEMS are currently available on the EPA's website.  The commenter stated that modifying these performance specifications specifically for a lead CEMS could be easily completed.
      Commenter 81 noted emissions during start-up, shutdown, and/or malfunctions can represent a significant fraction of a plant's emissions.  The commenter contends that it is critical to be able to monitor emissions during SSM periods and that it is impossible to do so unless a CEMS is in place.
      Commenter 85 provided data regarding an X-ray fluorescence based multi-metals continuous emissions monitor.  The commenter also provided proposed performance specifications and on-going QA procedures for lead CEMS.  Commenter 85 also later submitted comments requesting that the EPA comment on all aspects of its original comments, citing specifically the adequacy of the presented data in demonstrating the feasibility of using the Xact as a Pb CEMS, the feasibility of the performance specifications, on-going quality assurance procedures, and the submitted traceability protocol, and any changes the agency feel may be necessary to assure the data quality of Pb CEMS.  The commenter also states that the Xact instrument cost is $141,665 with an annual operating cost of $10,693.
      Response: It is not appropriate to require lead CEMS for new or existing sources absent a promulgated performance specification for this technology. There is not a numerical standard for HAP metals other than lead; therefore, the effectiveness of a CEMS at measuring these metals is not relevant to compliance with subpart X. We also note that measuring mercury content in scrap metals is not required by this rule, so it is unclear how the presence of a CEMS capable of measuring mercury would affect a facility with respect to measuring mercury content in scrap.
      With respect to facilities reconfiguring their stacks to make their facility more amenable to CEMS and prevent emissions from shorter stacks, we note that the risk assessment considered risks from all stacks, regardless of height and the results were considered in our decision making regarding the lead emission limit. The process of developing a performance specification for a monitoring method involves a period of notice and comment. Since a performance specification was not included in the proposed rule, the public was not provided with an opportunity to comment on the performance specification provided by the commenters after the proposal. The performance specifications provided by the commenters have been provided to the appropriate EPA staff. However, we do not find it appropriate to approve the performance specifications in the context of this final rule without first providing the public an opportunity to comment. With regard to the commenter's request that the EPA respond to the specific issues raised in their late comments, we reiterate that a lead CEMS performance specification must be proposed and finalized as a rulemaking action and the issues raised by the commenter are best addressed through that rulemaking. When such a performance specification is proposed by the EPA, the public will have the opportunity to comment on the types of issues raised in the commenter's letter, such as ongoing quality assurance procedures and traceability protocols. These issues are best addressed through that rulemaking. The technical basis of the performance specification will be evaluated by EPA staff when developing the proposed performance specification for this technology. Subsequently, the application of a lead CEMS to demonstrate compliance in this rulemaking must be evaluated with respect to whether the current form of the emission standard (based on manual test data) is appropriate.
      Comment:  Commenters 90 and 96 commented on data and comments submitted by Cooper Environmental Services and Pall Corporation regarding a commercially available lead CEM.  The commenters note that Cooper Environmental Services informed the ABR that the CEM cost approximately $400,000 per stack to install, a cost that the commenters claims is extremely high and would be multiplied many times over as facilities in this industry typically have 7-8 stacks.  The commenters note further concern that the price of a lead CEM could rise if the EPA requires it as the technology is only offered by one company.
      The commenters stated that there is no discussion in the record justifying the need for advances in monitoring and surveillance on stack sources in this industry, nor is there any indication that the BLDS technology that is currently required is inadequate.  The commenters claim that Cooper Environmental Service's comments are "rife with irrelevant and incorrect information".  The commenters further noted that Cooper Environmental Service's comments regarding multi-metal CEMS are irrelevant as the EPA neither proposed multi-metal CEMS nor requested comment on their applicability.
      Response: We agree that measurement of HAP metals other than lead is not necessary for compliance with subpart X and therefore not relevant to this rulemaking. We have considered the cost estimates provided by all commenters and maintain that it is appropriate to include the requirement for lead CEMS for new sources. However, this requirement will not be effective until a lead CEMS performance specification has been promulgated. 
      Comment:  Four commenters (90, 93, 95, and 96) stated that the EPA should abandon its proposal to require CEMS for new and modified sources.  The commenters stated that because the EPA has not set forth a performance specification for a lead CEM, stakeholders are unable to assess the systems and their applicability to this industry.  The commenters also argued that the EPA must assess cost-effectiveness under Section 112(f)(2)(A).  The commenters stated further stated that the EPA's analysis of technological feasibility for CEM is inadequate.  The commenters also express concern over using a different method to show compliance than the one used to set the standard.  The commenters further stated that lead CEMS should not be included in Subpart X until performance specifications and procedures are promulgated and feasibility and effectiveness on secondary lead smelters has been demonstrated.
      Response:  A performance specification for lead CEMS will be promulgated prior to the requirement becoming effective in this subpart. The process for promulgating a lead CEMS method includes proposing such a method and providing the opportunity for public comment.  In addition, EPA would consider as part of the rulemaking proceeding, whether it is appropriate to adjust the level of any standard measured by a CEM considering the more frequent measurement and hence dampening of variability over time of multiple measurements.
      
Bag Leak Detection Systems (BLDS)
      Comment: Commenter 90 stated that the current language in § 63.543(f), (g), and (h) require annual compliance testing for lead, THC, and D/F for all process vents.  The commenter contends that the term process vent in the proposed rule includes sources that are either not suitable for testing given their configuration or do not have emissions limits in the proposed rule.  The commenter stated that D/F and THC testing should be limited only to those sources that have emission limitations on D/F and THC.
      The commenter further stated that the Johnson Controls facility will utilize filtered roof exhausts that do not have stacks that allow measurement of velocity or meet isokinetic sampling requirements under EPA Method 29.  The commenter stated that the following sources should be excluded from the definition of process vent: roof exhausts equipped with HEPA filters, vents from buildings that are not partial or total enclosures, and building vents from non-lead bearing process areas.
      Response:  We have revised the proposed regulatory text to clarify that compliance tests need only be conducted for those sources that have emissions limitations for the applicable pollutant.  We agree that building vents from non-lead bearing process areas should be excluded from the definition of process vent and have reflected such in the regulatory text.  However, we disagree that all roof exhausts equipped with HEPA filters should be excluded from the definition of process vent.
      Comment:  Commenter 93 stated that the requirement for monthly calculation of flow-weighted average emissions is unnecessary and represents an additional burden without benefit.  The commenter argued that sources will typically schedule the annual compliance tests for all process vents at a facility in the same week, and therefore, the results produced by the monthly calculation will not change over a period of nearly a year.  Therefore, requiring the facilities to perform complicated summation calculations for multiple process vent stacks each month when the results each month will be the same provides no additional benefit or assurance of compliance with the standard.
      Response: We disagree that performing a calculation of flow-weighted average emissions is complex or represents an unnecessary additional burden.  We understand that it is possible that facilities may test different process vents at different times throughout the year.  Calculating the flow-weighted average emissions on a monthly basis will ensure that the value consistently includes the most up-to-date stack test data available.
      Typographical Corrections
      Comment: Commenter 92 requested clarification on a footnote of Table 2 that references January 2010 NEI data as being the basis for which emissions from this source category were estimated.  The commenter stated their understanding that the NEI is developed on a 3-year cycle and that 2010 is not one of the development years.  The commenter further stated that since the 2005 NEI data was used in the risk assessment, an explanation as to why an alternative year was utilized in the socio-economic analysis should be provided.
      Response:  The commenter is correct that 2010 is not a development year.  The 2005 NEI data was used for the socio-economic analysis.
      SSM and Affirmative Defense
      Comment: Commenter 98 agreed with the EPA in the removal of the unlawful malfunction exemption under the existing rules, but noted that the EPA failed to assess cancer and non-cancer chronic health risk from malfunction or other violations of the MACT standard.  Specifically;
      
      EPA must consider the full potential for risk from all emissions that are likely to occur, even though the standard is in place, not just the risk based on the "allowable" number of emissions.  
      
      EPA acknowledges that malfunctions inevitably occur.  EPA has information available or can collect information on major sources' malfunction and violation history.  Research by the Environmental Integrity Project ("EIP") from 2004 found that significant emission exceedances occur routinely, across a range of different industries.  Moreover, EIP found that "releases from upsets actually dwarf a facility's routine emissions. EPA must look at data, like the EIP report, and ensure that its risk analysis and resulting standard prepare for the likelihood that malfunctions will occur and that the public will need protection from the high emissions they cause.
      
      EPA cannot ignore the additional emissions from malfunctions or other violations in calculating risk. It may not assume that malfunction or other violation-based emissions are zero when it knows that they are not and when its own proposal is likely to perpetuate the problem of malfunctions in overburdened communities. For the purpose of assessing health risk, EPA cannot presume that a facility will be in full compliance with the standard at all times, as this runs counter to past history.
      
      By failing to account for the heightened risk from exceedances of the MACT in its calculation, EPA fails to consider the full risk to public health and the environment from this source, especially for the maximum exposed individual and most-affected communities. This violates section 112(f)(2). The Act specifically requires EPA to base its risk analysis on the highest possible level of risk "to the individual most exposed to emissions from a source in the category or subcategory." 42 U.S.C. § 7412(f)(2)(A); § 7412(f)(1)(C). To do this, it is necessary for EPA to determine the highest level of potential emissions from the worst-performing source, and then use that information to establish the maximum individual risk. That requires consideration of risk from malfunction- and other violation-based emissions. Heightened emissions that occur during a malfunction and other types of violations pose increased acute health risks, as EPA has recognized. 76 Fed. Reg. at 29,040. Chronic cancer and non-cancer health risks may also be more severe than those calculated by EPA because of malfunction/violation emissions. For example, EPA's MIR (maximum individual risk of cancer) is based on the assumption that exposure is constant for a lifetime (unless EPA uses age dependent adjustment factors). Failing to look at the true potential for spikes will significantly underestimate the amount of emissions considered for this analysis.
      EPA has accounted for some risk beyond the "MACT allowable" emission level in its acute health risk assessment, demonstrating that it is necessary and appropriate to do so for all parts of the risk assessment. To calculate acute health risk, EPA is using a "worst-case" scenario approach that appears to include some accounting for additional health risk due to upsets, malfunctions or other exceedances of the standard. For acute health risk, EPA is using a peak hourly emissions number that is "10 times the average annual hourly emissions rate for that source." 76 Fed. Reg. at 29,040. EPA's use of a factor that accounts for risk beyond the "MACT allowable" emissions number for acute risk in some manner in the proposed rule demonstrates that EPA has found a method to account for risk from higher than allowable emissions that occur from malfunctions and violations. It must apply a similar method to assess the maximum lifetime cancer risk and chronic non-cancer health risk for the maximum exposed individual. The failure to do so violates § 112(f)(2) and is arbitrary and capricious. The fact that EPA has done this for acute health risk shows that it is possible to do and should also be done for the other health risks that EPA must address in this rulemaking.
      
      Commenters also urge EPA to improve its acute health risk analysis by using a similar worst-case factor for fugitive dust emissions as well as stack emissions. EPA cannot justify ignoring the potential for increased fugitive dust emissions to occur as a result of a malfunction or violation, whether or not the malfunction is combined with low-wind atmospheric conditions, as it attempts to do. 76 Fed. Reg. at 29,040. Further, accurately evaluating fugitive dust emissions is crucial because these emissions are the largest contributor to lead emission risks. See id. at 29,038.
      
Response: We disagree with the commenter that emissions that exceed standards and are violations, whether or not caused by malfunction events, should be considered as part of the risk analysis. The purpose of the risk review is to evaluate whether the emission limits should be made more stringent to reduce the risk posed after compliance with the underlying MACT standard. To the extent that a source is violating the underlying MACT standard, no tightening of the emission standard under the residual risk rule will avoid or mitigate against such violations. In other words, a source that is violating the MACT emissions standard promulgated under section 112(d) would not be any more likely to be able to avoid such violations and comply with a different presumably more stringent standard promulgated under section 112(f). Such events are violations and subject to enforcement by the EPA, the States or citizens and an action for injunctive relief is the most effective means to address violations whether or not they are caused by malfunctions if an emissions event poses a significant health or environmental risk.
Although we disagree that emissions that result in a violation should be considered as part of the risk review, we note that we believe malfunction events do not contribute significantly to cancer or chronic non-cancer risks for the source category in this rulemaking because malfunction events are inherently short-term and infrequent relative to annual operations and emissions. The commenter did not supply any data to the contrary.
Furthermore, the conservative estimates built into the acute risk assessment are sufficient to gauge worst-case potential acute health effects. The conservative estimates built in to the assessment include worst-case meteorology, emissions at ten times the maximum peak emission rate from all point sources simultaneously, and the summation of the maximum impact of each emission source, regardless of receptor location. Thus, even if we were to consider emissions that are in violation of the standard, we do not believe that they would result in any different level of control than we are promulgating here.
Comment: Commenter 98 noted that the affirmative defense is unlawful and unjust, would create a new unlawful loophole, would have harmful consequences for communities, undermines citizen's rights, and will greatly reduce the deterrent impact of the standards: 
      
      Commenters support EPA's proposed removal of the start-up, shut-down, and malfunction exemption... However, EPA's proposal to promulgate an "affirmative defense" to penalties due to a malfunction would create a new unlawful loophole.   It also would have harmful consequences for local communities affected by secondary lead smelters, and will greatly reduce the deterrent impact of the proposed standards.

      The statute makes clear how the courts are to assess civil penalties, whether a case is brought by EPA or a citizen. 42 U.S.C. § 7413(e). Congress plainly intended citizens to be able to enforce emission standards under the CAA using the full range of civil enforcement mechanisms available to the government, and, in the HAP context, subject only to the limitation that government not be "diligently prosecuting" its own civil enforcement action, CAA § 304(b)(1)(B), 42 U.S.C. § 7604(b)(1)(B). EPA's rule proposal, by shifting this careful balance and contravening these mandates, violates the CAA.
   
      The affirmative defense that the EPA proposes to allow in case of malfunctions goes directly against congressional intent in two ways. First, Congress expressed a clear intent as to how judges should determine the size of civil penalties whenever they are sought and thus, under Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 842-43 (1984), flatly barred the EPA from limiting when civil penalties can be assessed. In this proposal, the EPA acts outside of its delegated authority to limit civil penalties available in citizen suits or its own enforcement actions. Second, the proposal will impermissibly chill citizen participation, and the ability to win an effective, deterrent remedy, in CAA enforcement actions. 
      The affirmative defense is fatally flawed because the EPA does not have the authority to decide when civil penalties will not be allowed. The CAA itself spells out the only limits that Congress intended to impose on citizens' ability to seek and recover penalties in enforcement suits under CAA § 304, 42 U.S.C. § 7604. See 42 U.S.C. § 7413(e). By attempting to impose additional agency-created limits, the EPA exceeds its authority. The commenter goes on to say:
   
Congressional intent on civil penalties is clear -- they are a remedy available to citizen plaintiffs, and judges have a list of factors to consider in assessing them. As such, EPA cannot interpret the statute to contravene that intent. By attempting to eliminate, via regulations, civil penalties in cases of malfunction where the violator demonstrates that certain factors [exist], EPA has done just that.
The CAA grants EPA minimal discretion that only applies to administrative penalties, allowing EPA to "compromise, modify, or remit, with or without conditions, any administrative penalty which may be imposed under [subsection 113(d)]." 42 U.S.C. § 7413(d)(2)(B).  However, there is no similar grant of authority to EPA to compromise, modify or limit civil penalties that a court may impose under section 113(e) or section 304. Section 304(a), 42 U.S.C. § 7604(a), grants courts the sole authority "to apply appropriate civil penalties" in citizen suits. The explicit reference to EPA's ability to modify penalties in one subsection and its absence in the other subsection of the same provision can only be understood as an intentional decision by Congress that EPA cannot contravene by rule.

      If a local community group sued a covered facility for a violation of the emission standards, the owner might argue that it is exempt from paying civil penalties so long as the owner satisfied the requirements set forth in the EPA's proposed affirmative defense regulations. See 76 Fed. Reg. at 29,061-62 (proposing 40 C.F.R. § 63.552). The owner must not be able to evade civil penalties that apply when the congressionally mandated factors in the statute are met. 210 See 42 U.S.C. § 7413(e) (listing factors). It is improper for a court to fail to consider these factors, or to fail to make its own determination of what civil penalties are "appropriate" under CAA § 304(a), and the EPA should not ask a court to ignore its legal duty.  A fortiori it is impermissible for the EPA to attempt to displace those factors or in any way alter their significance by creating a bar to penalties if certain agency-defined considerations are met instead.
      Citizen participation in CAA enforcement also will be hindered, in violation of citizens' rights to protect themselves from pollution and in direct conflict with congressional intent. The affirmative defense would likely be used on a routine basis by polluters seeking to avoid penalties, just as the malfunction exemption was. As a result, citizens who seek the assessment of civil penalties against polluters in order to protect themselves and achieve the Act's goals may be forced to engage in fact-intensive disputes over the cause of emission violations and adequacy of responsive measures  -  an outcome Congress intended to prevent with the simple straightforward enforcement and penalty provisions in the Clean Air Act. As a result, enforcement of the Act could suffer, for civil penalties provide a powerful deterrent to violators as Congress intended. As the Supreme Court explained: "To the extent that they [civil penalties] encourage defendants to discontinue current violations and deter them from committing future ones, they afford redress to citizen plaintiffs who are injured or threatened with injury as a consequence of ongoing unlawful conduct." Friends of the Earth, Inc. v. Laidlaw Envtl. Servs., 528 U.S. 167, 186 (2000).  Thus, the affirmative defense also runs counter to two clearly expressed intentions of Congress: (1) the burden it places on citizens makes it less likely that they will enforce the Act, see, e.g., Pennsylvania v. Del. Valley Citizens' Council for Clean Air, 478 U.S. 546, 560 (1986); and (2) several of the factors at issue in the affirmative defense undercut Congress's intent that citizen suit enforcement should avoid re-delving into "technological or other considerations." NRDC v. Train, 510 F.2d 692, 724 (D.C. Cir. 1974). Both result from the technical burden the EPA imposes on citizens with the affirmative defense, and both render the defense impermissible.
      In addition to these problems, there is simply no need for an affirmative defense to penalties to be written into the regulations and cause the harm that will result. EPA has discretion to decide what cases to prosecute, to consider settlements, and to request civil penalties in a case-by-case manner, as long as it acts consistent with the Clean Air Act to protect clean air as its top priority, see 42 U.S.C. § 7401. Promulgating this affirmative defense is equivalent to giving polluters "get out of jail free" cards for serious emission exceedances and MACT violations. Polluters are likely to claim that any violation of the standard is due to a malfunction in order to evade the requirements. Allowing polluters to evade financial penalties  -  which are the real teeth of the standards  -  through this type of measure is likely to lead to polluters simply ignoring or factoring potential standard violations into their cost of doing business, rather than actually trying to prevent malfunctions and violations of the standards as a way to avoid financial losses from the application of penalties.
      
      Assuming arguendo that the EPA had authority to promulgate any type of affirmative defense to penalties for malfunctions, the EPA should also promulgate the following provisions:
      
      1. A specific amount of compensatory penalties should apply to each reported malfunction (consistent with the Act). These funds should be dedicated to enforcement, inspections, and monitoring in the local community around the specific facility, to create greater assurance that malfunctions will not happen again.
      
      2.   The EPA should modify the regulations so that the affirmative defense cannot be used by a specific facility or company more than once within a set period of time, such as 10 years. The affirmative defense should become automatically unavailable to a facility that has previously had a malfunction within the last 10 years, to ensure that this defense does not swallow the value of the standards.

      3.   The EPA should promulgate specific public reporting and notification requirements for malfunctions, or any emission exceedance that occurs of which an operator is aware. Specifically, the EPA should require that when a facility provides the EPA with a notification of a malfunction or emission standard exceedance under the regulations, this notice will be made publicly available on the EPA's website within 14 days. In addition, the EPA should promulgate the requirement that when such notification is made, the facility must also provide for community notification of the malfunction or emission standard exceedance within 2 business days, through an appropriate public forum that is designed to reach residents who live near the facility, including but not limited to a notice on the facility's own website (if it has one), a written notice to the local municipality and local school district, a press release to the local newspaper, radio, and TV news station that contains information community members may need to protect themselves and their families from the additional air pollution.
      
      Commenters urge the EPA not to adopt an affirmative defense that undermines citizen right and remedies under the Clean Air Act. People living near secondary lead smelters are exposed to unacceptably high levels of hazardous air pollution that no one should have to face simply because of where they live. Attempting to take away a right granted to citizens by Congress through an agency regulation sets a dangerous precedent. The EPA should work to expand and protect the ability of people harmed by air pollution to seek all appropriate and available forms of relief in court. The EPA should not retract or weaken citizen rights and remedies, as this proposal does, by making it more difficult for people to win meaningful relief from facilities that have released toxic air pollution into their communities for years.
      Response: As the EPA explained in the preamble to the proposed rule and in the response to comment document, the EPA recognizes that even equipment that is properly designed and maintained can fail and that such failure can cause an exceedance of the relevant emission standard. The EPA included an affirmative defense in the final rule in an attempt to balance a tension, inherent in many types of air regulation, to ensure adequate compliance while simultaneously recognizing that despite the most diligent of efforts, emission limits may be exceeded under circumstances beyond the control of the source. The EPA must establish emission standards that "limit the quantity, rate, or concentration of emissions of air pollutants on a continuous basis." 42 U.S.C. § 7602(k)(defining "emission limitation and emission standard"). See generally Sierra Club v. EPA, 551 F.3d 1019, 1021 (D.C. Cir. 2008) ( emissions limitations under CAA section 112 must both continuously apply and meet section 112's minimum stringency requirements, even during periods of startup, shutdown and malfunction). Thus, the EPA is required to ensure that section 112 emissions limitations are continuous. The affirmative defense for malfunction events meets this requirement by ensuring that even where there is a malfunction, the emission limitation is still enforceable through injunctive relief. While "continuous" limitations, on the one hand, are required, there is also caselaw indicating that in many situations it is appropriate for the EPA to account for the practical realities of technology. For example, in Essex Chemical v. Ruckelshaus, 486 F.2d 427, 433 (D.C. Cir. 1973), the D.C. Circuit acknowledged that in setting standards under CAA section 111 "variant provisions" such as provisions allowing for upsets during startup, shutdown and equipment malfunction "appear necessary to preserve the reasonableness of the standards as a whole and that the record does not support the `never to be exceeded' standard currently in force." See also, Portland Cement Association v. Ruckelshaus, 486 F.2d 375 (D.C.Cir. 1973). Though intervening caselaw such as Sierra Club v. EPA and the CAA 1977 amendments undermine the relevance of these cases today, they support the EPA's view that a system that incorporates some level of flexibility is reasonable. The affirmative defense simply provides for a defense to civil penalties for excess emissions that are proven to be beyond the control of the source. By incorporating an affirmative defense, the EPA has formalized its approach to upset events. In a Clean Water Act setting, the Ninth Circuit required this type of formalized approach when regulating "upsets beyond the control of the permit holder." Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9[th] Cir. 1977). But see, Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an informal approach is adequate). The affirmative defense provisions give the EPA the flexibility to both ensure that its emission limitations are "continuous" as required by 42 U.S.C. § 7602(k), and account for unplanned upsets and thus support the reasonableness of the standard as a whole.
      Further, the EPA's view is that the affirmative defense is not inconsistent with CAA section 113(e) or 304. Section 304 gives district court's jurisdiction "to apply appropriate civil penalties." Section 113(e)(1) identifies the factors that the Administrator or a court shall take into consideration in determining the amount of a penalty to be assessed, once it has been determined that a penalty is appropriate. The affirmative defense regulatory provision is not relevant to the amount of any penalty to be assessed. If a court determines that the affirmative defense elements have been established, then a penalty is not appropriate and penalty assessment pursuant to the section 113(e)(1) factors does not occur.    
      In exercising its authority under section 112 to establish emission standards (at a level that meets the stringency requirements of section 112), the EPA necessarily defines conduct that constitutes a violation. The EPA view is that the affirmative defense is part of the emission standard and defines two categories of violation. If there is a violation of the emission standard and the source demonstrates that all the elements of the affirmative defense are met, only injunctive relief is available. All other violations of the emission standard are subject to injunctive relief and penalties. The CAA does not require that all violations be treated equally. Further, a citizen suit claim under section 304 allows citizens to commence a civil action against any person alleged to be in violation of "an emission standard or limitation under this chapter." The CAA, however, allows the EPA to establish such "enforceable emission limitations." Thus, the citizen suit provision clearly contemplates enforcement of the standards that are defined by the EPA. As a result, where the EPA defines its emissions limitations and enforcement measures to allow a source the opportunity to prove its entitlement to a lesser degree of violation (not subject to penalties) in narrow, specified circumstances, as the EPA did here, penalties are not "appropriate" under section 304.  
      The EPA's view is that an affirmative defense to civil penalties for exceedances of applicable emission standards during periods of malfunction appropriately balances competing concerns. On the one hand, citizen enforcers are concerned about additional complications in their enforcement actions. On the other hand, industrial sources are concerned about being penalized for violations caused by malfunctions that could not have prevented and were otherwise appropriately handled (as reflected in the affirmative defense criteria). The EPA has utilized its Section 301(a)(1) authority to issue regulations necessary to carry out the Act in a manner that appropriately balances these competing concerns.
      The EPA disagrees that the affirmative defense provision will hamper citizen enforcement. First, injunctive relief is still available and the threat of penalties would not deter violations in cases where all of the conditions of the affirmative defense have been satisfied because the affirmative defense criteria ensure that all reasonable steps were taken to prevent a malfunction that causes excess emissions. Further, litigating whether a source has met the affirmative defense will not burden citizen group any more or less than would litigating the appropriate penalty amount in the penalty assessment stage of a citizen suit enforcement action, because the 113(e) penalty assessment criteria and the affirmative defense criteria are similar and in fact overlap. For example, the requirement that the Administrator or the court consider "good faith efforts to comply" is bound to generate the type of fact-intensive disputes that the commenter complains of. In addition, several of the affirmative defense criteria are exactly the type of criteria the Administrator or Court might consider in determining whether a source made "good faith efforts to comply." For example, to take advantage of the affirmative defense, the source must prove by a preponderance of the evidence that, among other things, the excess emissions "were caused by an unavoidable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner" and "could not have been prevented through careful planning, proper design or better operation and maintenance practices" and "did not stem from any activity or event that could have been foreseen and avoided, or planned for." 
      Thus, the EPA does not expect the affirmative defense provision to significantly alter the burden of bringing a citizen enforcement action. For those cases that do proceed to trial, even in the absence of this affirmative defense, sources generally raise equitable arguments to argue for a low penalty and citizens often rebut such arguments. Therefore, as a practical matter, the EPA does not expect the affirmative defense provision to materially affect the practice of CAA enforcement.
      Additionally, the affirmative defense is reasonable. The EPA's judgment is that the affirmative defense criteria capture the appropriate considerations in determining whether penalties are appropriate when a violation occurs as the result of a malfunction. As noted above, the affirmative defense criteria overlap to some extent with the penalty assessment criteria set forth in section 113(e), but are not identical. For example, size of business is one of the factors listed in section 113(e), but is not reflected in the EPA's affirmative defense. This reflects the EPA's view that when a violation is caused by a malfunction, the size of the business is not relevant to whether penalties should be excused. If the violation was unavoidable and could not have been prevented, the EPA's view is that it would be unfair to impose a penalty no matter the size of the business.  
      The EPA is not adopting commenters' suggestion with respect to compensatory damages or limits on the frequency of use of the affirmative defense. It is not clear that the EPA has authority to require the automatic imposition of compensatory damages and even if such authority exists, the EPA does not think automatic imposition of damages is appropriate. Ensuring that malfunctions do not recur can be handled through imposition of appropriate injunctive relief. In addition, the EPA's view is that it would not be appropriate to limit a source's ability to take advantage of the affirmative defense to one time over a specified period of time such as ten years given that the affirmative defense is only available when the source could not have prevented the excess emissions. With respect to commenters' suggested reporting requirements, the reporting requirements in the rules promulgated today already require malfunction reporting and the affirmative defense provisions require that parties choosing to assert the affirmative defense meet additional malfunction reporting requirements. Any such reports submitted to the EPA are publicly available pursuant to CAA section 114.
      Comment: Commenter 111 stated that the affirmative defense provisions do not cure the EPA's failure to set emission standards that are achievable during SSM events and are not a substitute for setting emissions standards for these periods. The commenter further state that the proposed standards with the affirmative defense do not represent emission limitations achieved by the best-performing existing sources, nor do they meet the criteria for establishing beyond-the-floor emission standards and that the affirmative defense is not a permissible substitute for setting standards for periods of malfunction and is insufficient to meet the EPA's obligations under CAA §112.  Commenter 87 requests the EPA set aside the proposed affirmative defense for periods of malfunction and establish a work practice standard for these periods.
      Response: The affirmative defense applies to malfunction events and not to periods of startup and shutdown. The affirmative defense is not intended as a substitute for standards under section 112  -  the applicable standard applies during malfunctions, but a source may assert an affirmative defense in an enforcement action for penalties for emissions in excess of the standard. Elsewhere in this document, we address the commenter's concern regarding whether the EPA has met its obligation under section 112 in addressing emissions during startup and shutdown. 
      Comment: Commenter 96 and 90 advised that the EPA should promulgate work practice standards for emissions during startups, shutdowns and malfunctions, rather than requiring compliance with the proposed emissions standards during these events.  The EPA has not demonstrated that the best-performing units can achieve the proposed MACT emission standards during SSM events.  The commenter stated that "the unpredictability and variability of emissions during SSM events makes measuring their emissions infeasible using current measurement methods..."  Commenter 90 suggested that the standards should require the development and implementation of an emissions minimization plan that would be a dynamic document maintained at the facility. 
      Response: Work practice standards have been included in the final rule for startup and shutdown periods where a facility will not be able to demonstrate compliance with the D/F and THC limits based performance testing during these periods. See section III.A.3 of the final rule preamble for a discussion of these work practice standards and the impracticality of performance testing for THC and D/F during periods of startup and shutdown. No exemption for startup periods was requested or determined to be necessary for the lead emission standard.
      Comment: Commenter 90 provided additional support for incorporating work practice standards for periods of SSM.  According to the commenter:

      EPA claims that its approach to SSM is required by Sierra Club v. EPA, 551 F.3d
      1019 (D.C. Cir. 2008), cert. denied, 2010 U.S. LEXIS 2265 (2010). In this decision, the D.C. Circuit vacated the exemption in 40 C.F.R. § 63.6(f)(1) and (h)(1) for SSM periods, and in light of this decision, EPA proposed emissions standards in the RTR Proposed Rule that apply at all times, including periods of SSM. 76 Fed. Reg. at 29,072.
      
      When setting standards in the early 1990's under CAA § 112(d), EPA used its New Source Performance Standards (NSPS) program as a model. The § 112 standards were acknowledged by EPA to be "essentially equivalent to [§ 111] performance standards" and that "unpredicted and reasonably unavoidable failures of air pollution control systems" would occur. 58 Fed. Reg. at 42,762, 42,777 (Aug. 11, 1993). To address this situation, EPA adopted an exemption similar to the one in the NSPS Program for SSM events and imposed a "general duty" to minimize emissions. Thus, EPA acknowledged, as early as 1993, that SSM events are not appropriate for inclusion in a MACT standard and that an alternative approach should be used to address these situations. While the D.C. Circuit in the Sierra Club vs. EPA case ruled that sources cannot be exempt from complying with MACT standards, the court noted that Congress recognized in some instances that it may not be feasible to prescribe or enforce an emission standard under § 112, and so § 112(h) "work practices" or "operational" standards are available in certain situations. See Sierra Club v. EPA, 551 F.3d at 1028.
      
      The D.C. Circuit also has recognized that standards based on what sources achieve must account for the limitations inherent in the technology used to reduce emissions. For example, in a case reviewing NSPS under § 111 of the CAA, Portland Cement Ass'n v. Ruckelshaus, 486 F.2d 375, 398 (D.C. Cir. 1973), the court acknowledged that " 'start-up' and 'upset' conditions due to plant or emission device malfunction, is an inescapable aspect of industrial life and that allowance must be made for such factors in the standards that are promulgated." Id. Furthermore, in National Lime Ass'n v. EPA, 627 F.2d 416 (D.C. Cir. 1980), the court noted that "a uniform standard must be capable of being met under most adverse conditions which can reasonably be expected to recur." Id. at 431 n.46. The D.C. Circuit acknowledged this same principle almost 20 years later when reviewing emission standards for new sources in the medical waste incinerator rule under § 129 in Sierra Club v. EPA, 167 F.3d 658 (D.C. Cir. 1999). In that case, while the court did not find the record sufficient to support EPA's approach for new sources, the D.C. Circuit did not object to a standard-setting approach which would account for the performance of technology under the "worst reasonably foreseeable circumstances." See id. at 665. Furthermore, the D.C. Circuit reiterated the principle in National Lime that "where a statute requires that a standard be 'achievable,' it must be achievable 'under the most adverse circumstances which can reasonably be expected to recur.' " Id. at 665 (citing National Lime Ass'n v. EPA, 627 F.2d 416, 431 n.46 (D.C. Cir. 1980)). EPA has determined that CAA section 112 does not require that emissions that occur during periods of malfunction be factored into development of CAA section 112 standards." 76 Fed. Reg. at 29,061. Considering that EPA's proposed MACT standards are supposed to apply at all times, the implication is that periods of malfunction also are covered by the MACT standards that apply during normal operations. This approach directly conflicts with the statutory requirement that the MACT standard be "achievable." EPA has failed to recognize what Congress acknowledged in enacting §112: that it is likely that even best performers will experience malfunctions. It is possible for pollution control equipment to fail in various ways. Power failures do occur, fabric filters fail, scrubber pumps fail even at best performers and despite the best efforts of companies to prevent and minimize such events. Industry can and does work to minimize such periods, but they do occur. Further, manufacturers of such equipment routinely make emission guarantees for normal operations and although they sometimes oversize equipment to account for some of the variability described above, it is very doubtful that vendors would provide sufficient numerical guarantees for equipment under such situations. Given that the MACT floor data does not consider malfunctions and that the statute requires that the MACT standard be "achievable," EPA should, if it is determined that it is appropriate to amend the MACT at all, set work practice requirements to address periods of malfunctions as well.
      
      Response: We have included work practice standards for periods of startup and shutdown for THC and D/F.   With respect to standards for lead, EPA believes that the standards that otherwise apply are also appropriate for startup and shutdown because the bag leak detection systems used to determine compliance with the emission standard for lead operates properly during these periods.  With respect to malfunctions, we do not find it appropriate to make a blanket determination that work practices should be applied for periods of malfunctions (which do not always cause situations that will satisfy the criteria of section 112(h) regarding technical and economic practicality of measuring emissions). We have included an affirmative defense to civil penalties for malfunctions in the final rule that addresses situations that are beyond the control of the owner or operator, reflecting the caselaw in this area, as stated in response at pages 117-121 of this document. 
      Comment: Commenter 90 stated that the EPA's basis of cost for implementation of the affirmative defense is not supported, and in their estimate is significantly less than what would be expected. The EPA's estimate of the number of occurrences per year of 2-3 seems low as well.
       Response:  We believe that the cost estimate for implementation of the affirmative defense is reasonable.  The commenter provided no specific data to support their claims.

      Request for Comment Period Extension
      Comment:  Several commenters requested more time to review the proposed package.  Three commenters (70.1, 72, 73) requested a 60 day extension, one commenter (80) requested a 58 day extension, and one commenter (71) requested a 45 day extension.
      Commenters 70, 71, and 73 stated that the period for comments is insufficient to allow them to fully review the proposed rule and docket materials, and develop meaningful comments to assist the Agency in finalizing its proposal.  Commenter 72 stated that the proposal raises a host of complicated issues that warrant careful consideration in order to comment meaningfully.  Commenter 73 stated that an extension is warranted because not all documents on which the EPA relied in drafting the proposed rule were located in the docket on May 19.  The commenter further noted that the comment period included Memorial Day and Independence Day, effectively shortening the time available to conduct the necessary analyses.  Commenter 74 notes that the comment period for the EPA's proposed rule and that for the EPA's First External Review Draft Integrated Science Assessment for Lead share a common deadline.  The commenter contends that it is not reasonable to review both of these lengthy documents on the same time frame.
      Response:  The EPA granted a 21 day extension of the comment period. The 21 day extension was the longest that the EPA could grant while still providing enough time to meet the court-ordered deadline for signature of this final rule.  See also response at pages 127-127 below, explaining in more detail why further extensions were inappropriate and unnecessary.	
      Miscellaneous
      Comment: Commenter 80 provided comment on the Draft Summary of Ambient Lead Monitoring Data near Secondary Lead Smelting Facilities document (EPA-HQ-2011-0344-0041).  The commenter stated that two of the monitoring sites listed for the Buick Resource Recycling Facility are not ambient, but are located within the facility fenceline and should not appear in the table.  The commenter also notes that the listed maximum 3-month concentration of 2.46 ug/m[3] at site 29093016 in 2008 resulted from an upset condition at the facility, not typical operation.
      Response:  We have added footnotes to the applicable tables of the technical document clarifying the commenter's points.
      Comment: Commenter 78 and 83 stated that they support the proposed rule as published.
      Response: We acknowledge the commenters' support.
      Comment:  Industry respondents (90, 95, 96) commented on the EPA's statement in the preamble to the proposed rule that "No new secondary lead smelters have been built in the last 20 years, and we anticipate no new secondary lead smelting facilities in the foreseeable future, although there is one facility currently in the process of expanding operations."  The commenters note a secondary lead smelting facility that is currently operating in Puerto Rico.  Additionally, JCI is currently constructing a battery recycling facility in Florence, S.C., and Exide Technologies holds an active Title V permit for a facility in Columbus, GA.  The commenters contend that the EPA's failure to accurately and completely describe the industry is grounds for withdrawal and re-proposal of the rule.
      Response:  The commenters are correct in their statements regarding these facilities.  However, we note that the JCI facility in Florence, SC and the Exide facility in Columbus, GA are not operational.  Therefore, `emissions' (non-existent) from these two facilities could not have affected any revised emissions limits in the proposed rulemaking.
      With regards to the Puerto Rico facility, the EPA contacted The Battery Recycling Company requesting information in an effort to determine the potential impacts of the proposed rule on this facility.  The stack test data obtained by the EPA revealed that stack emissions of lead from this facility are below the limit proposed by the EPA and therefore would not have affected the EPA's stance that its proposed emissions limit for lead for this source category is technologically feasible and represents a level that is achieved in practice by a well-performing fabric filter. The data received can be found in docket ID: EPA-HQ-OAR-2011-0344-0124 and EPA-HQ-OAR-2011-0344-0125. With regards to total hydrocarbons and dioxins and furans from rotary furnaces, EPA is not setting section 112 (d) standards in this rule because of an absence of data to represent performance of rotary furnaces and is now preparing to send out section 114 information requests to obtain additional data.   We have conducted analyses to evaluate the cost impacts of the proposed rule on the aforementioned facilities and have revised the technical document describing the cost impacts accordingly.  None of the data or information collected from these facilities alters the decisions made by the EPA in this rulemaking.  As such, we do not believe that this issue merits delay of this rulemaking.
      Comment:  Commenter 75 requested that the EPA issue a supplemental notice of rulemaking for the secondary lead smelting NESHAP.  The commenter claims that there are "significant problems with the proposed rule that undermine EPA's proposed MACT floors and its Risk and Technology Review (RTR)."
      First, the commenter notes that the proposed rule fails to consider emissions from The Battery Recycling Company's secondary lead smelter in Puerto Rico.  The commenter notes that, with regards to risk, the EPA is required to consider emission from all members in the source category.  The commenter further notes that the MACT floors proposed by the EPA for THC and D/F must be based on the best-performing 5 sources and that the EPA's failure to consider emissions from the Puerto Rico facility prejudices these standards.
      Second, the commenter states that the proposed rule is flawed because its risk review is based on a overestimation of dioxin emissions at the Exide Frisco facility.  The commenter notes that Exide conducted a stack test in October 2010 demonstrating emissions 69 times lower than the estimate used by the EPA in its risk assessment.
      Third, the commenter states that a supplemental notice of proposed rulemaking would allow the EPA to take into account additional stack testing data submitted by the industry.
      Response:  We do not believe that it is appropriate to issue a supplemental notice of rulemaking for this source category.  We received data from the overwhelming majority of the industry in the ICR developed for the proposal. However, we did obtain data from the Battery Recycling Company after the proposal and the data did not change any of the substantive conclusions of the rulemaking. As noted in the final rule preamble, we have deferred standards for organic HAP and dioxin for rotary furnaces. We will collect data from the Battery Recycling Company and the JCI facility currently under construction in South Carolina (if it is operational) and use those data to develop appropriate emission standards for those pollutants. The test data for dioxins and furans from the Exide Frisco facility mentioned by the commenter were not made available to the EPA until June of 2011, despite the testing being conducted in October 2010. The EPA requested these data from Exide repeatedly before the proposal and did not receive them. As noted by the commenter, the data showed that the multipathway risks from dioxins and furans are below 1 in a million. However, the overestimated risk used in the proposal did not lead to any emission standards for dioxins and furans being proposed under section 112(f). These data thus did not substantively change any decisions made for this rulemaking making it unnecessary to reopen the comment period. There were two additional stack tests mentioned by the commenter. First, the commenter mentioned that RSR's Middletown, NY facility was performing additional testing on their rotary furnace for THC or dioxins and furans. However, the facility provided additional test data for lead and confirmed that they did not perform additional testing for THC or dioxins and furans. The additional lead test data showed that the tested furnace was meeting the lead emission standard promulgated in this final rule. The second test cited by the commenter occurred at the Exide Reading facility but was not provided to the EPA until late November 2011, too late to be incorporated into the MACT floor calculations (although, as noted, inclusion of those data might have made the standard slightly more stringent). The concerns presented by the commenter have been addressed elsewhere in this document.
      Comment:  Commenters 86, 92, and 98 recommended that the EPA adopt a consolidated emissions reporting rule for HAPs.  According to the commenters, "The lack of a federal requirement to collect the basic information on how many HAPs are released from stationary sources into the surrounding community is a serious impediment to any attempt to evaluate total HAP exposure and risk in a sound technical manner."
      Response:  We agree and the EPA is currently considering how to collect such data.
      Comment:  Commenter 98 stated that the EPA should commit to review and update its residual risk determination in this final rule  at the same time as it is next required to review its § 112(d) technology-based standard (i.e., 8 years from promulgation of the final rule).
      Response:   This comment is beyond the scope of this rule.  
      Comment:  Commenter 130 stated that the EPA finalized far less prescriptive design standards and work practices for the primary lead processing source category than it proposed for the secondary lead smelting category.  The commenter believes that the less prescriptive work practices and design standards should be applied to the secondary lead smelting rule.  Specific proposed work practices that were proposed for secondary lead include the water application rate in pavement cleaning, the requirement to wash building roofs, and the requirement to conduct all maintenance activities within enclosures. The primary lead rule does not require these work practices. 
      Response:   We have revised the list of required work practices to remove redundancy or potential workplace hazards based on a number of comments received on the proposed rule for the secondary lead smelting source category. The specific water application rate for pavement cleaning, and the requirement to wash building roofs which EPA proposed are not included as requirement in the final rule.  The proposed requirement to perform all maintenance activities within enclosures has been modified to ensure that maintenance activities that could generate lead dust are conducted in a manner that minimizes emissions of fugitive dust. However, the final list of work practice standards will ensure that fugitive dust is not generated outside of total enclosures, thereby ensuring the public is protected with an ample margin of safety. 
      Comment:  Commenter 130 discussed the requirement for total enclosures to be maintained at a negative pressure of at least 0.02 mm of Hg with an in-draft velocity of 300 feet per minute with continuous multiple negative pressure monitoring units fitted with backup power supplies.  The commenter compared the final primary lead standard to the proposed secondary lead standard.  The primary lead standard is less prescriptive than the proposed secondary lead standard, and the commenter stated that there is no reason that the design standards for enclosures need to be more prescriptive.  
      Response:  We believe that monitoring of building differential pressure is the most accurate means by which to ensure that the enclosure building is under negative pressure at all times. This method provides direct measurements that the building is indeed maintained at negative pressure and thus not emitting contained material. Some commenters stated that specifying doorway velocities could require substantial additional in-draft, which could cause strain to building structures, wind chill problems for workers, and pilot lights being extinguished. We agree with these comments and have therefore removed the proposed requirement to measure in-draft velocity at the openings of the total enclosures, but have retained the continuous differential pressure monitoring requirement. However, we have altered the differential pressure requirement from 0.02 mm of mercury to 0.013 mm of mercury to be consistent with the EPA Method 204's criteria for verification of a permanent or temporary total enclosure. Because fugitive lead emissions are the predominant contributor to overall risk for the secondary lead source category, EPA concluded that total enclosures with continuous monitoring of negative pressure were appropriate for this category.     
      Comment: Commenter 130 compared the bag leak detection system requirement in the proposed secondary lead rule to the requirement in the final primary lead rule.  The EPA proposed to remove the 1997 NESHAP exemption in the secondary lead rule for bag leak detection system on baghouses fitted with secondary HEPA filtration.  In the final primary lead rule, EPA included this exemption.  
      Response:  We agree with the commenters that baghouses equipped with HEPA filters do not need bag leak detection systems as well. Measurement of pressure drop across a HEPA filter provides the needed information to determine that the filter is performing effectively so a bag leak detection system would be redundant.
      Comment: Commenter 130 noted that a comment by the ABR was included in the primary lead rule docket opposing the proposed requirement that new primary lead processing facilities install and operate continuous emission monitoring systems for lead.  The comment also explained why the EPA should not include a similar requirement in the secondary lead smelting rule.  The ABR comment to the primary lead proposed rule stated that without setting a performance specification at the time of proposal, there is no way for the commenter to meaningfully assess the system and the potential applicability.  There is no assurance that the CEM technology will be sufficiently sensitive and robust to provide reliable data on emissions for secondary lead smelter stacks.  Additionally the requirement to install a CEMS would impose a cost burden that would be greater than any incremental environmental benefit. 
      Response: We have considered the cost estimates provided by all commenters and maintain that it is appropriate to include the requirement for lead CEMS for new sources. However, a performance specification for lead CEMS will be promulgated prior to the requirement becoming effective in this subpart. The process for promulgating a lead CEMS method includes proposing such a method and providing the opportunity for public comment.  In addition, EPA would consider as part of the rulemaking proceeding, whether it is appropriate to adjust the level of any standard measured by a CEM considering the more frequent measurement and hence dampening of variability over time of multiple measurements.
      Comment: Commenter 127 submitted late comments in response to late-filed additional comments from the Pall Corporation.  The commenter is concerned that EPA is not providing a complete record of supporting materials in the docket, in that minutes of a meeting between EPA and Pall in September 2011 are not docketed.  The commenter noted that the comments provided by Pall do not include any explanation as to why the information was not submitted before the end of the comment period.  The commenter does not believe there is sufficient information in the EPA's proposal and supporting documentation regarding the feasibility, performance specifications or quality assurance procedures of a Pb CEMS.  The cost noted by the Pall Corporation in the late-filed comments is incomplete and misleading in that it does not include all installation costs. 
      Response: While the commenter is correct that the additional comments submitted by the Pall Corporation were received after the close of the public comment period, that does not bar the EPA from considering those comments, just as it did not bar the EPA from considering the multiple comments submitted by ABR after the close of the public comment period.  The additional comments submitted by the Pall Corporation essentially emphasized their request that the agency respond to their original comments rather than raising new issues (with the exception of new cost information). The updated cost information provided by the Pall Corporation did include caveats that certain costs were excluded, as mentioned by the commenter. The EPA has considered both the cost estimate provided by the commenter and by Pall Corporation. The costs submitted by the commenter ($400,000 per device) were the values that the EPA used to determine whether it was appropriate to require these devices for new sources. We deemed that it was appropriate. Whether the costs remain at $400,000 or are indeed lower, we maintain that it is an appropriate requirement. With regard to comments on the feasibility of a Pb CEMS, the EPA has included the requirement for new sources to install a CEMS only after the performance specifications for a lead CEMS method have been promulgated.  The EPA will conduct an investigation into the feasibility and cost effectiveness of a Pb CEMS before as a part of the rulemaking process for the performance specification. That rulemaking will involve a public comment period during which the commenter may inform the EPA of any potential problems with the performance specification that is proposed.  The total cost of installing and operating a CEMS will be considered in the evaluation. Notes from the September 2011 between the EPA and Pall Corporation were posted in the docket well before the signature date of the final rule, see EPA-HQ-OAR-2011-0344-0128.  


