[Federal Register Volume 79, Number 243 (Thursday, December 18, 2014)]
[Proposed Rules]
[Pages 75621-75719]
[FR Doc No: 2014-28125]

Vol. 79

Thursday,

No. 243

December 18, 2014

Part II

Environmental Protection Agency

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40 CFR Part 63

NESHAP for Brick and Structural Clay Products Manufacturing; and NESHAP
for Clay Ceramics Manufacturing; Proposed Rules

Federal Register / Vol. 79 , No. 243 / Thursday, December 18, 2014 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2013-0290 and EPA-HQ-OAR-2013-0291; FRL-9913-58-OAR]
RIN 2060-AP69

NESHAP for Brick and Structural Clay Products Manufacturing; and
NESHAP for Clay Ceramics Manufacturing

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing
national emission standards for hazardous air pollutants (NESHAP) for
brick and structural clay products manufacturing and NESHAP for clay
ceramics manufacturing. The EPA is proposing that all major sources in
these categories meet maximum achievable control technology (MACT)
standards for mercury, non-mercury metal hazardous air pollutants (HAP)
(or particulate matter (PM) surrogate) and dioxins/furans (Clay
Ceramics only); health-based standards for acid gas HAP; and work
practice standards, where applicable. The proposed rule, which has been
informed by input from industry and other stakeholders, including small
businesses, would protect air quality and promote public health by
reducing emissions of HAP listed in section 112 of the Clean Air Act
(CAA).

DATES: Comments. Comments must be received on or before February 17,
2015. A copy of comments on the information collection provisions
should be submitted to the Office of Management and Budget (OMB) on or
before January 20, 2015.
    Public Hearing. If anyone contacts the EPA requesting a public
hearing by January 15, 2014 the EPA will hold a public hearing on
January 20, 2015 from 1:00 p.m. [Eastern Standard Time] to 5:00 p.m.
[Eastern Standard Time] at the U.S. Environmental Protection Agency
building located at 109 T.W. Alexander Drive, Research Triangle Park,
NC 27711. If the EPA holds a public hearing, the EPA will keep the
record of the hearing open for 30 days after completion of the hearing
to provide an opportunity for submission of rebuttal and supplementary
information.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2013-0291 for Brick and Structural Clay Products
Manufacturing and EPA-HQ-OAR-2013-0290 for Clay Ceramics Manufacturing,
by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov:
Follow the on-line instructions for submitting comments.
     Email<EMAIL_ADDRESS>Include Docket ID No. EPA-
HQ-OAR-2013-0291 for Brick and Structural Clay Products Manufacturing
or EPA-HQ-OAR-2013-0290 for Clay Ceramics Manufacturing in the subject
line of the message.
     Fax:<PHONE_NUMBER>.
     Mail: Environmental Protection Agency, EPA Docket Center
(EPA/DC), Mailcode 28221T, Attention Docket ID No. EPA-HQ-OAR-2013-0291
(for Brick and Structural Clay Products Manufacturing) or EPA-HQ-OAR-
2013-0290 (for Clay Ceramics Manufacturing), 1200 Pennsylvania Ave.
NW., Washington, DC 20460. In addition, please mail a copy of your
comments on the information collection provisions to the Office of
Information and Regulatory Affairs, Office of Management and Budget
(OMB), Attn: Desk Officer for EPA, 725 17th Street NW., Washington, DC
20503.
     Hand/Courier Delivery: EPA Docket Center, Room 3334, EPA
WJC West Building, 1301 Constitution Ave. NW., Washington, DC 20004.
Such deliveries are only accepted during the Docket's normal hours of
operation and special arrangements should be made for deliveries of
boxed information.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2013-0291 for Brick and Structural Clay Products Manufacturing or EPA-
HQ-OAR-2013-0290 for Clay Ceramics Manufacturing. The EPA's policy is
that all comments received will be included in the public docket
without change and may be made available online at http://www.regulations.gov, including any personal information provided,
unless the comment includes information claimed to be confidential
business information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through http://www.regulations.gov or
email. The http://www.regulations.gov Web site is an ``anonymous
access'' system, which means the EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send an email comment directly to the EPA without going through
http://www.regulations.gov, your email address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the Internet. If you submit an
electronic comment, the EPA recommends that you include your name and
other contact information in the body of your comment and with any disk
or CD-ROM you submit. If the EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, the
EPA may not be able to consider your comment. Electronic files should
not include special characters or any form of encryption and be free of
any defects or viruses. For additional information about the EPA's
public docket, visit the EPA Docket Center homepage at: http://www.epa.gov/dockets.
    Docket. The EPA has established dockets for this rulemaking under
Docket ID No. EPA-HQ-OAR-2013-0291 for Brick and Structural Clay
Products Manufacturing and Docket ID No. EPA-HQ-OAR-2013-0290 for Clay
Ceramics Manufacturing. All documents in the dockets are listed in the
regulations.gov index. Although listed in the index, some information
is not publicly available, e.g., CBI or other information whose
disclosure is restricted by statute. Certain other material, such as
copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy. Publicly available docket
materials are available either electronically in regulations.gov or in
hard copy at the EPA Docket Center, EPA WJC West Building, Room 3334,
1301 Constitution Ave. NW., Washington, DC. The Public Reading Room is
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744 and the telephone number for the EPA Docket Center is
(202) 566-1742.
    Public Hearing. If requested by January 15, 2014, we will hold a
public hearing on January 20, 2015, from 1:00 p.m. [Eastern Standard
Time] to 5:00 p.m. [Eastern Standard Time] at the U.S. Environmental
Protection Agency building located at 109 T.W. Alexander Drive,
Research Triangle Park, NC 27711. Please contact Ms. Pamela Garrett of
the Sector Policies and Programs Division (D243-01), Office of Air
Quality Planning and Standards, Environmental Protection Agency,
Research Triangle Park, NC 27711; telephone number:<PHONE_NUMBER>;
email address<EMAIL_ADDRESS>to request a hearing, register
to speak at the hearing or to inquire as to whether or not a hearing
will be held. The last day to pre-register in advance to speak at the
hearing will be December 30, 2014. Additionally, requests to speak will
be taken the day of the hearing at the hearing registration desk,
although

preferences on speaking times may not be able to be fulfilled. If you
require the service of a translator or special accommodations such as
audio description, we ask that you pre-register for the hearing, as we
may not be able to arrange such accommodations without advance notice.
The hearing will provide interested parties the opportunity to present
data, views or arguments concerning the proposed action. The EPA will
make every effort to accommodate all speakers who arrive and register.
Because this hearing is being held at a U.S. government facility,
individuals planning to attend the hearing should be prepared to show
valid picture identification to the security staff in order to gain
access to the meeting room. Please note that the REAL ID Act, passed by
Congress in 2005, established new requirements for entering federal
facilities. If your driver's license is issued by Alaska, American
Samoa, Arizona, Kentucky, Louisiana, Maine, Massachusetts, Minnesota,
Montana, New York, Oklahoma or the state of Washington, you must
present an additional form of identification to enter the federal
building. Acceptable alternative forms of identification include:
Federal employee badges, passports, enhanced driver's licenses and
military identification cards. In addition, you will need to obtain a
property pass for any personal belongings you bring with you. Upon
leaving the building, you will be required to return this property pass
to the security desk. No large signs will be allowed in the building,
cameras may only be used outside of the building and demonstrations
will not be allowed on federal property for security reasons. The EPA
may ask clarifying questions during the oral presentations, but will
not respond to the presentations at that time. Written statements and
supporting information submitted during the comment period will be
considered with the same weight as oral comments and supporting
information presented at the public hearing. Verbatim transcripts of
the hearing and written statements will be included in the docket for
the rulemaking. The EPA will make every effort to follow the schedule
as closely as possible on the day of the hearing; however, please plan
for the hearing to run either ahead of schedule or behind schedule.
Again, a hearing will not be held on this rulemaking unless requested.
A hearing needs to be requested by December 23, 2014. Again, please
contact Ms. Pamela Garrett of the Sector Policies and Programs Division
(D243-01), Office of Air Quality Planning and Standards, Environmental
Protection Agency, Research Triangle Park, NC 27711; telephone number:
(919) 541-7966; email address<EMAIL_ADDRESS>to request a
hearing.

FOR FURTHER INFORMATION CONTACT: For questions about the proposed rule
for Brick and Structural Clay Products Manufacturing and Clay Ceramics
Manufacturing, contact Ms. Sharon Nizich, Minerals and Manufacturing
Group, Sector Policies and Program Division (D243-04), Office of Air
Quality Planning and Standards, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; Telephone number: (919)
541-2825; Fax number:<PHONE_NUMBER>; Email address:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Preamble Acronyms and Abbreviations. This preamble includes several
acronyms and terms used to describe industrial processes, data
inventories and risk modeling. While this list may not be exhaustive,
to ease the reading of this preamble and for reference purposes, the
EPA defines the following terms and acronyms here:

3xRDL representative detection level values multiplied by three
ACI activated carbon injection
AEGL Acute Exposure Guideline Level
AERMOD air dispersion model used by the HEM-3 model
APCD air pollution control device
ATSDR Agency for Toxic Substances and Disease Registry
BDL below detection limit
BLD bag leak detection
BSCP brick and structural clay products
CAA Clean Air Act
CalEPA California EPA
CAS Chemical Abstract Services
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
Cl2 chlorine
CO carbon monoxide
CPMS continuous parameter monitoring system
DHHS Department of Health and Human Services
DIFF dry lime injection fabric filter
DLA dry limestone adsorber
DLL detection level limited
DLS/FF dry lime scrubber/fabric filter
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guideline
ERT Electronic Reporting Tool
[deg]F degrees Fahrenheit
FF fabric filter
FTIR Fourier transform infrared
gr/dscf grains per dry standard cubic foot
HAP hazardous air pollutant
HCl hydrogen chloride
HEM-3 Human Exposure Model (Community and Sector version 1.3.1)
HF hydrogen fluoride
Hg mercury
HQ hazard quotient
IARC International Agency for Research on Cancer
ICR information collection request
IOM Institute of Medicine
IRFA initial regulatory flexibility analysis
IRIS Integrated Risk Information System
K kurtosis statistic
lb/hr pounds per hour
lb/ton pounds per ton
LML lowest measured level
MACT maximum achievable control technology
mg/m\3\ milligrams per cubic meter
MMBtu/yr million British thermal units per year
MRL Minimal Risk Level
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NATA National Air Toxics Assessment
NEI National Emissions Inventory
NESHAP national emissions standards for hazardous air pollutants
ng/dscm nanograms per dry standard cubic meter
No. number
NO2 nitrogen dioxide
NOAEL no observable adverse effect level
non-Hg non-mercury
NOX nitrogen oxides
NTTAA National Technology Transfer and Advancement Act
O2 oxygen
OM&M operation, maintenance and monitoring
OMB Office of Management and Budget
PIC products of incomplete combustion
PLC programmable logic controller
PM particulate matter
PM2.5 particulate matter with particles less than 2.5
micrometers in diameter
RDL representative detection level
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RIA Regulatory Impact Analysis
S skewness statistic
SBA Small Business Administration
SBAR Small Business Advocacy Review
SBE Standard Brick Equivalent
SBREFA Small Business Regulatory Enforcement Fairness Act
SEK standard error of kurtosis
SER small entity representative
SES standard error of skewness
SO2 sulfur dioxide
SSM startup, shutdown and malfunction
TCDD tetrachlorodibenzo-p-dioxin
TEQ 2,3,7,8-TCDD toxic equivalents
TOSHI target organ-specific hazard index
tph tons per hour
tpy tons per year
TTN Technology Transfer Network
UMRA Unfunded Mandates Reform Act
[mu]g/dscm micrograms per dry standard cubic meter
[mu]g/m\3\ micrograms per cubic meter
UPL Upper Prediction Limit
VCS voluntary consensus standards
VE visible emissions
WHO World Health Organization

    Organization of This Document. The information in this preamble is
organized as follows:

I. General Information
    A. Executive Summary
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related
information?
    D. What should I consider as I prepare my comments for the EPA?
II. Background Information
    A. What is the statutory authority for the proposed rule?
    B. What is the background for startup, shutdown and malfunction?
    C. What is the history of the proposed rule?
    D. What are the health effects of pollutants emitted from the
Brick and Structural Clay Products and Clay Ceramics Manufacturing
source categories?
III. Summary of the Proposed Rule for the Brick and Structural Clay
Products Manufacturing Source Category
    A. What source category is affected by the proposed rule?
    B. What are the affected sources?
    C. Does the proposed rule apply to me?
    D. What emission limitations and work practice standards must I
meet?
    E. What are the startup and shutdown requirements?
    F. What are the testing and initial compliance requirements?
    G. What are the continuous compliance requirements?
    H. What are the notification, recordkeeping and reporting
requirements?
    I. How would I submit emissions test results to the EPA?
IV. Rationale for the Proposed Rule for Brick and Structural Clay
Products Manufacturing
    A. How did the EPA determine which sources would be regulated
under the proposed rule?
    B. How did the EPA select the format for the proposed rule?
    C. How did the EPA consider different subcategories?
    D. What approaches did the EPA consider in developing the
proposed emission limitations for existing and new sources?
    E. How did the EPA determine the MACT floors for existing
sources?
    F. How did the EPA determine the MACT floor for new sources?
    G. What is our approach for applying the upper prediction limit
to limited datasets?
    H. How did the EPA consider beyond-the-floor for existing
sources?
    I. How did the EPA consider beyond-the-floor for new sources?
    J. How did the EPA determine whether to set health-based
standards for existing and new sources?
    K. How did the EPA determine whether to set work practice
standards for existing and new sources?
    L. How did the EPA develop the startup and shutdown
requirements?
    M. How did the EPA select the compliance requirements?
    N. How did the EPA determine compliance times for the proposed
rule?
    O. How did the EPA determine the required records and reports
for the proposed rule?
    P. How does the proposed rule affect permits?
    Q. What are the alternate approaches the EPA is considering?
V. Summary of the Proposed Rule for the Clay Ceramics Manufacturing
Category
    A. What source category is affected by the proposed rule?
    B. What are the affected sources?
    C. Does the proposed rule apply to me?
    D. What emission limitations and work practice standards must I
meet?
    E. What are the startup and shutdown requirements?
    F. What are the testing and initial compliance requirements?
    G. What are the continuous compliance requirements?
    H. What are the notification, recordkeeping and reporting
requirements?
    I. How would I submit emissions test results to the EPA?
VI. Rationale for the Proposed Rule for Clay Ceramics Manufacturing
    A. How did the EPA determine which sources would be regulated
under the proposed rule?
    B. How did the EPA select the format for the proposed rule?
    C. How did the EPA consider different subcategories?
    D. What approaches did the EPA consider in developing the
proposed emission limitations for existing and new sources?
    E. How did the EPA determine the MACT floors for existing
sources?
    F. How did the EPA determine the MACT floors for new sources?
    G. What is our approach for applying the upper prediction limit
to limited datasets?
    H. How did the EPA consider beyond-the-floor for existing
sources?
    I. How did the EPA consider beyond-the-floor for new sources?
    J. How did the EPA determine whether to set health-based
standards for existing and new sources?
    K. How did the EPA determine whether to set work practice
standards for existing and new sources?
    L. How did the EPA develop the startup and shutdown
requirements?
    M. How did the EPA select the compliance requirements?
    N. How did the EPA determine compliance times for the proposed
rule?
    O. How did the EPA determine the required records and reports
for the proposed rule?
    P. How does the proposed rule affect permits?
VII. Summary of the Environmental, Energy and Economic Impacts of
the Proposed Standards
    A. What are the cost and emission reduction impacts?
    B. What are the secondary impacts?
    C. What are the economic impacts?
    D. What are the social costs and benefits of the proposed rule?
VIII. Public Participation and Request for Comment
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    Section 112(d) of the CAA requires the EPA to set emissions
standards for HAP emitted by major stationary sources based on the
performance of the MACT. We issued the NESHAP for Brick and Structural
Clay Products (BSCP) manufacturing and the NESHAP for Clay Ceramics
Manufacturing on May 16, 2003. The two NESHAP were vacated and remanded
by the United States Court of Appeals for the District of Columbia
Circuit on March 13, 2007. To address the vacatur and remand of the
original NESHAP, we are proposing new standards for BSCP manufacturing
and clay ceramics manufacturing.
2. Summary of the Major Provisions
    BSCP NESHAP. The EPA is proposing MACT emission limits for mercury
(Hg) and non-mercury (non-Hg) HAP metals (or PM surrogate) and a
health-based emission limit for acid gases (hydrogen fluoride (HF),
hydrogen chloride (HCl) and chlorine (Cl2)) for BSCP tunnel
kilns. In addition, the EPA is proposing work practice standards for
periodic kilns, for dioxins/furans from tunnel kilns and for periods of
startup and shutdown for tunnel kilns. To demonstrate compliance with
the emission limits, the EPA is proposing initial and repeat 5-year
performance testing for the regulated pollutants, continuous parameter
monitoring and daily visible emissions (VE) checks. Owners/operators
whose BSCP tunnel kilns are equipped with a fabric filter (FF) (e.g.,
dry lime injection fabric filter (DIFF), dry lime scrubber/fabric
filter (DLS/FF)) have the option of

demonstrating compliance using a bag leak detection (BLD) system
instead of daily VE checks.
    Clay Ceramics NESHAP. The EPA is proposing MACT emission limits for
Hg, PM (surrogate for non-Hg HAP metals) and dioxins/furans and health-
based emission limits for acid gases (HF and HCl) for sanitaryware
tunnel kilns and ceramic tile roller kilns. In addition, the EPA is
proposing MACT emission limits for dioxins/furans for ceramic tile
spray dryers and floor tile press dryers, MACT emission limits for Hg
and PM (surrogate for non-Hg HAP metals) for ceramic tile glaze lines
and MACT emission limits for PM (surrogate for non-Hg HAP metals) for
sanitaryware glaze spray booths. The EPA is also proposing work
practice standards for shuttle kilns and for periods of startup and
shutdown. To demonstrate compliance with the emission limits, the EPA
is proposing initial and repeat 5-year performance testing for the
regulated pollutants, continuous parameter monitoring and daily VE
checks. Owners/operators whose affected sources are equipped with a FF
(e.g., DIFF, DLS/FF) have the option of demonstrating compliance using
a BLD system instead of daily VE checks.
3. Costs and Benefits
    Table 1 of this preamble summarizes the costs and benefits of this
proposed action for 40 CFR part 63, subpart JJJJJ (BSCP Manufacturing
NESHAP), while Table 2 of this preamble summarizes the costs of this
proposed action for 40 CFR part 63, subpart KKKKK (Clay Ceramics
Manufacturing NESHAP). See section VII of this preamble for further
discussion of the costs and benefits for the BSCP Manufacturing NESHAP
and the costs for the Clay Ceramics Manufacturing NESHAP. See section
IX.B of this preamble for discussion of the recordkeeping and reporting
costs.

                   Table 1--Summary of the Costs and Benefits of 40 CFR Part 63, Subpart JJJJJ
                                           [Millions of 2011 dollars]
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                 Requirement                    Capital cost     Annual cost               Net benefit
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Emission controls............................         $54.9           $18.4     $26 to $99.
Emissions testing............................           0.977           0.238
Monitoring...................................  ..............           0.346
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     Table 2--Summary of the Costs of 40 CFR Part 63, Subpart KKKKK
                       [Millions of 2011 dollars]
------------------------------------------------------------------------
           Requirement               Capital cost         Annual cost
------------------------------------------------------------------------
Emission controls...............                  $0                  $0
Emissions testing...............               0.102              0.0249
Monitoring......................  ..................              0.0209
------------------------------------------------------------------------

B. Does this action apply to me?

    The regulated categories and entities potentially affected by the
proposed standards are shown in Table 3 of this preamble:

                Table 3--NESHAP and Industrial Source Categories Affected by This Proposed Action
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                                                                                Examples of potentially
                             Category                              NAICS code \a\        regulated entities
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Industry.........................................................          327120  Brick, structural clay and
                                                                                extruded tile manufacturing
                                                                                facilities (BSCP NESHAP);
                                                                                and ceramic wall and floor
                                                                                tile manufacturing
                                                                                facilities (Clay Ceramics
                                                                                NESHAP).
                                                                           327110  Vitreous plumbing fixtures
                                                                                (sanitaryware) manufacturing
                                                                                facilities (Clay Ceramics
                                                                                NESHAP).
Federal government...............................................  ..............  Not affected.
State/local/tribal government....................................  ..............  Not affected.
----------------------------------------------------------------------------------------------------------------
\a\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. To determine whether your facility, company, business,
organization, etc., would be regulated by this action, you should
examine the applicability criteria in 40 CFR 63.8385 of subpart JJJJJ
(BSCP Manufacturing NESHAP) or 40 CFR 63.8535 of subpart KKKKK (Clay
Ceramics Manufacturing NESHAP). If you have any questions regarding the
applicability of this proposed action to a particular entity, contact
either the air permitting authority for the entity or your EPA regional
representative as listed in 40 CFR 63.13 of subpart A (General
Provisions).

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

    In addition to being available in the docket, an electronic copy of
this action is available on the Internet through the EPA's Technology
Transfer Network (TTN) Web site, a forum for information and technology
exchange in various areas of air pollution control. Following signature
by the EPA Administrator, the EPA will post a copy of this proposed
action at http://www.epa.gov/ttn/atw/brick/brickpg.html. Following
publication in the Federal Register, the EPA will post the Federal
Register version of the proposal and key technical documents at this
same Web site.

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

    Do not submit information containing CBI to the EPA through http://www.regulations.gov or email. Clearly

mark the part or all of the information that you claim to be CBI. For
CBI information on a disk or CD-ROM that you mail to the EPA, mark the
outside of the disk or CD-ROM as CBI and then identify electronically
within the disk or CD-ROM the specific information that is claimed as
CBI. In addition to one complete version of the comments that includes
information claimed as CBI, you must submit a copy of the comments that
does not contain the information claimed as CBI for inclusion in the
public docket. If you submit a CD-ROM or disk that does not contain
CBI, mark the outside of the disk or CD-ROM clearly that it does not
contain CBI. Information not marked as CBI will be included in the
public docket and the EPA's electronic public docket without prior
notice. Information marked as CBI will not be disclosed except in
accordance with procedures set forth in 40 Code of Federal Regulations
(CFR) part 2. Send or deliver information identified as CBI only to the
following address: Roberto Morales, OAQPS Document Control Officer
(C404-02), OAQPS, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina 27711, Attention Docket ID No. EPA-HQ-
OAR-2013-0291 (for BSCP Manufacturing NESHAP) or Docket ID No. EPA-HQ-
OAR-2013-0290 (for Clay Ceramics Manufacturing NESHAP).

II. Background Information

A. What is the statutory authority for the proposed rule?

    Section 112(d) of the CAA requires the EPA to set emissions
standards for HAP emitted by major stationary sources based on the
performance of the MACT. The MACT standards for existing sources must
be at least as stringent as the average emissions limitation achieved
by the best performing 12 percent of existing sources (for which the
Administrator has emissions information) or the best performing five
sources for source categories with less than 30 sources (CAA section
112(d)(3)(A) and (B)). This level of minimum stringency is called the
MACT floor. For new sources, MACT standards must be at least as
stringent as the control level achieved in practice by the best
controlled similar source (CAA section 112(d)(3)). The EPA also must
consider more stringent ``beyond-the-floor'' control options. When
considering beyond-the-floor options, the EPA must consider not only
the maximum degree of reduction in emissions of HAP, but must take into
account the associated costs, energy and nonair environmental impacts.

B. What is the background for startup, shutdown and malfunction?

    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008), the United States Court of Appeals for the District of
Columbia Circuit vacated portions of two provisions in the EPA's CAA
section 112 regulations governing the emissions of HAP during periods
of startup, shutdown and malfunction (SSM). Specifically, the Court
vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR
63.6(h)(1), holding that under section 302(k) of the CAA, emissions
standards or limitations must be continuous in nature and that the SSM
exemption violates the CAA's requirement that some section 112
standards apply continuously.
    Consistent with Sierra Club v. EPA, we are proposing standards in
this rule that apply at all times. In proposing the standards in this
rule, the EPA has taken into account startup and shutdown periods and,
for the reasons explained in sections IV.L and VI.L of this preamble,
has proposed alternate standards for some sources during those periods.
    Periods of startup, normal operations and shutdown are all
predictable and routine aspects of a source's operations. Malfunctions,
in contrast, are neither predictable nor routine. Instead they are, by
definition sudden, infrequent and not reasonably preventable failures
of emissions control, process or monitoring equipment. The EPA
interprets CAA section 112 as not requiring emissions that occur during
periods of malfunction to be factored into development of CAA section
112 standards. Under section 112, emissions standards for new sources
must be no less stringent than the level ``achieved'' by the best
controlled similar source and for existing sources generally must be no
less stringent than the average emission limitation ``achieved'' by the
best performing 12 percent of sources in the category. There is nothing
in CAA section 112 that directs the agency to consider malfunctions in
determining the level ``achieved'' by the best performing sources when
setting emission standards. As the U.S. Court of Appeals for the
District of Columbia Circuit has recognized, the phrase ``average
emissions limitation achieved by the best performing 12 percent of''
sources ``says nothing about how the performance of the best units is
to be calculated.'' Nat'l Ass'n of Clean Water Agencies v. EPA, 734
F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts for
variability in setting emissions standards, nothing in CAA section 112
requires the agency to consider malfunctions as part of that analysis.
A malfunction should not be treated in the same manner as the type of
variation in performance that occurs during routine operations of a
source. A malfunction is a failure of the source to perform in a
``normal or usual manner'' and no statutory language compels the EPA to
consider such events in setting section CAA 112 standards.
    Further, accounting for malfunctions in setting emission standards
would be difficult, if not impossible, given the myriad different types
of malfunctions that can occur across all sources in the category and
given the difficulties associated with predicting or accounting for the
frequency, degree and duration of various malfunctions that might
occur. For these reasons, the performance of units that are
malfunctioning is not ``reasonably'' foreseeable. See, e.g., Sierra
Club v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999) (``The EPA typically
has wide latitude in determining the extent of data-gathering necessary
to solve a problem. We generally defer to an agency's decision to
proceed on the basis of imperfect scientific information, rather than
to `invest the resources to conduct the perfect study.' '') See also,
Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the
nature of things, no general limit, individual permit, or even any
upset provision can anticipate all upset situations. After a certain
point, the transgression of regulatory limits caused by `uncontrollable
acts of third parties,' such as strikes, sabotage, operator
intoxication or insanity, and a variety of other eventualities, must be
a matter for the administrative exercise of case-by-case enforcement
discretion, not for specification in advance by regulation.''). In
addition, emissions during a malfunction event can be significantly
higher than emissions at any other time of source operation. For
example, if an air pollution control device with 99-percent removal
goes off-line as a result of a malfunction (as might happen if, for
example, the bags in a baghouse catch fire) and the emission unit is a
steady state type unit that would take days to shut down, the source
would go from 99-percent control to zero control until the control
device was repaired. The source's emissions during the malfunction
would be 100 times higher than during normal operations, and the
emissions over a 4-day malfunction period would exceed the annual
emissions of the source during normal operations. As this example
illustrates, accounting for malfunctions could lead to standards

that are not reflective of (and significantly less stringent than)
levels that are achieved by a well-performing non-malfunctioning
source. It is reasonable to interpret CAA section 112 to avoid such a
result. The EPA's approach to malfunctions is consistent with CAA
section 112 and is a reasonable interpretation of the statute.
    In the event that a source fails to comply with the applicable CAA
section 112 standards as a result of a malfunction event, the EPA would
determine an appropriate response based on, among other things, the
good faith efforts of the source to minimize emissions during
malfunction periods, including preventative and corrective actions, as
well as root cause analyses to ascertain and rectify excess emissions.
The EPA would also consider whether the source's failure to comply with
the CAA section 112(d) standard was, in fact, ``sudden, infrequent, not
reasonably preventable'' and was not instead ``caused in part by poor
maintenance or careless operation.'' 40 CFR 63.2 (definition of
malfunction).
    If the EPA determines in a particular case that enforcement action
against a source for violation of an emission standard is warranted,
the source can raise any and all defenses in that enforcement action
and the federal district court will determine what, if any, relief is
appropriate. The same is true for citizen enforcement actions.
Similarly, the presiding officer in an administrative proceeding can
consider any defense raised and determine whether administrative
penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular,
section 112 is reasonable and encourages practices that will avoid
malfunctions. Administrative and judicial procedures for addressing
exceedances of the standards fully recognize that violations may occur
despite good faith efforts to comply and can accommodate those
situations.

C. What is the history of the proposed rule?

    Pursuant to CAA section 112(c)(5), the EPA was originally required
to promulgate standards for the BSCP Manufacturing and Clay Ceramics
Manufacturing source categories by November 2000. The agency initially
promulgated standards for these categories in 2003. See 68 FR 26690
(May 16, 2003). Those standards were challenged and subsequently
vacated by the Court of appeals for the District of Columbia Circuit in
2007. See Sierra Club v. EPA, 479 F.3d 875, 876 (D.C. Cir. 2007). In
2008, Sierra Club filed suit in the Court of Appeals for the District
of Columbia Circuit under CAA section 304(a)(2), alleging that the EPA
had a continuing mandatory duty to promulgate standards for these
categories under CAA section 112 based on the 2000 deadline under CAA
section 112(c)(5). The EPA challenged that claim in a motion to
dismiss, arguing that the mandatory duty to act by the 2000 deadline
was satisfied by the 2003 rule and that the 2007 vacatur of the 2003
rule did not recreate the statutory duty to act by the 2000 deadline.
Ultimately, the District Court found that the vacatur of the 2003 rule
recreated the mandatory duty to set standards by 2000 and held that
Sierra Club's claims could continue. See Sierra Club v. EPA, 850
F.Supp.2d 300 (D.D.C. 2012). The EPA and Sierra Club then negotiated a
consent decree to settle the litigation and establish proposal and
promulgation deadlines for establishing standards for these categories.
    Following the 2007 vacatur of the 2003 rule, the EPA began efforts
to collect additional data to support new standards for the BSCP and
clay ceramics industries. The EPA conducted an initial information
collection effort in 2008 to update information on the inventory of
affected units, hereafter referred to as ``the 2008 EPA survey.'' The
EPA conducted a second information collection effort in 2010 to obtain
additional emissions data and information on each facility's SSM
procedures, hereafter referred to as ``the 2010 EPA survey.'' The
information collected as part of these surveys and not claimed as CBI
by respondents is available in Docket ID Nos. EPA-HQ-OAR-2013-0290 and
EPA-HQ-OAR-2013-0291. In addition, the dockets A-99-30 and OAR-2002-
0054 are incorporated by reference for BSCP. The dockets A-2000-48,
OAR-2002-0055 and EPA-HQ-OAR-2006-0424 are incorporated by reference
for clay ceramics.

D. What are the health effects of pollutants emitted from the Brick and
Structural Clay Products Manufacturing and Clay Ceramics Manufacturing
source categories?

    The proposed rule protects air quality and promotes the public
health by reducing emissions of HAP emitted from BSCP and clay ceramics
kilns. Emissions data collected during development of the proposed rule
shows that acid gases such as HF, HCl and Cl2 represent the
predominant HAP emitted by BSCP and clay ceramics kilns, accounting for
99.3 percent of the total HAP emissions. These kilns also emit lesser
amounts of other HAP compounds such as HAP metals and dioxins/furans,
accounting for about 0.7 percent of total HAP emissions. The HAP metals
emitted include antimony, arsenic, beryllium, cadmium, chromium,
cobalt, lead, manganese, mercury, nickel and selenium. Exposure to
these HAP, depending on exposure duration and levels of exposures, can
be associated with a variety of adverse health effects. These adverse
health effects could include chronic health disorders (e.g., irritation
of the lung, skin and mucus membranes, effects on the central nervous
system and damage to the kidneys) and acute health disorders (e.g.,
lung irritation and congestion, alimentary effects such as nausea and
vomiting and effects on the kidney and central nervous system). We have
classified two of the HAP as human carcinogens (arsenic and chromium
VI) and four as probable human carcinogens (cadmium, lead, dioxins/
furans and nickel).

III. Summary of the Proposed Rule for the Brick and Structural Clay
Products Manufacturing Source Category

    This section summarizes the requirements for the BSCP Manufacturing
source category proposed in today's action. Section IV of this preamble
provides our rationale for the proposed requirements.

A. What source category is affected by the proposed rule?

    Today's proposed rule for BSCP Manufacturing applies to BSCP
manufacturing facilities that are located at or are part of a major
source of HAP emissions. The BSCP Manufacturing source category
includes those facilities that manufacture brick (face brick,
structural brick, brick pavers and other brick); clay pipe; roof tile;
extruded floor and wall tile; and/or other extruded, dimensional clay
products.

B. What are the affected sources?

    The affected sources, which are the portions of each source in the
category for which we are setting standards, are: (1) all tunnel kilns
at a BSCP manufacturing facility; and (2) each periodic kiln. For
purposes of this proposed BSCP manufacturing rule, tunnel kilns are
defined to include any type of continuous kiln used at BSCP
manufacturing facilities, including roller kilns.
    Tunnel kilns are fired by natural gas or other fuels, including
sawdust. Sawdust firing typically involves the use of a sawdust dryer
because sawdust typically is purchased wet and needs to be dried before
it can be used as fuel.

Consequently, some sawdust-fired tunnel kilns have two process streams,
including: (1) A process stream that exhausts directly to the
atmosphere or to an APCD and (2) a process stream in which the kiln
exhaust is ducted to a sawdust dryer where it is used to dry sawdust
before being emitted to the atmosphere. Both process streams are
subject to the requirements of today's proposed BSCP manufacturing
rule.
    The following BSCP process units are not subject to the
requirements of today's proposed rule: (1) kilns that are used
exclusively for setting glazes on previously fired products and (2)
dryers. See section IV.A of this preamble for information on why these
sources are not subject to the proposed BSCP manufacturing rule.

C. Does the proposed rule apply to me?

    This proposed BSCP manufacturing rule applies to owners or
operators of an affected source at a major source meeting the
requirements discussed previously in this preamble. A major source of
HAP emissions is any stationary source or group of stationary sources
located within a contiguous area and under common control that emits or
has the potential to emit, considering controls, 10 tons per year (tpy)
or more of any HAP or 25 tpy or more of any combination of HAP.

D. What emission limitations and work practice standards must I meet?

1. Emission Limitations
    We are proposing a choice of emission limits for total non-Hg HAP
metals for all new and existing tunnel kilns. The options include a
total non-Hg HAP metals limit (pounds per hour (lb/hr)) and options for
limiting PM as a surrogate for non-Hg HAP metals (pounds per ton (lb/
ton) or grains per dry standard cubic foot (gr/dscf) at 7 percent
oxygen (O2)). We are also proposing a choice of emission
limits for Hg (lb/ton, lb/hr or micrograms per dry standard cubic meter
([micro]g/dscm) at 7 percent O2) for new and existing tunnel
kilns in two subcategories based on kiln size. In this proposed BSCP
manufacturing rule, a large tunnel kiln is defined as a new or existing
tunnel kiln with a design capacity of 10 tons per hour (tph) or greater
and a small tunnel kiln is defined as a new or existing tunnel kiln
with a design capacity of less than 10 tph. We are also proposing an
emission limit for HCl-equivalent for all existing and new tunnel kilns
at the facility to reduce the acid gases HF, HCl and Cl2.
The proposed emission limits for Hg and non-Hg HAP metals are presented
in Table 4 of this preamble.

    Table 4--Proposed Total Non-Mercury HAP Metals and Mercury Emission Limits for Brick and Structural Clay
                                              Products Tunnel Kilns
----------------------------------------------------------------------------------------------------------------
             Subcategory                      Acid gases        Total non-Hg HAP metals             Hg
----------------------------------------------------------------------------------------------------------------
                                           Limits for existing sources
----------------------------------------------------------------------------------------------------------------
Large tunnel kilns...................  .......................  .......................  2.2 E-05 lb/ton OR 2.7
(>= 10 tph)..........................                                                     E-04 lb/hr OR 29
                                                                                [micro]g/dscm at 7-
                                                                                percent O2 for each
                                                                                existing large tunnel
                                                                                kiln at facility.
Small tunnel kilns...................  .......................  .......................  2.0 E-04 lb/ton OR
(< 10 tph)...........................                                                     0.0011 lb/hr OR 70
                                                                                [micro]g/dscm at 7-
                                                                                percent O2 for each
                                                                                existing small tunnel
                                                                                kiln at facility.
All tunnel kilns.....................  57 lb/hr HCl-equivalent  0.16 lb/ton PM OR 0.040
                                        for collection of all    gr/dscf PM at 7
                                        existing tunnel kilns    percent O2 OR 0.023 lb/
                                        at facility.             hr non-Hg HAP metals
                                                                 for each existing
                                                                 tunnel kiln at
                                                                 facility.
----------------------------------------------------------------------------------------------------------------
                                             Limits for new sources
----------------------------------------------------------------------------------------------------------------
Large tunnel kilns...................  .......................  .......................  2.0 E-05 lb/ton OR 2.4
(>= 10 tph)..........................                                                     E-04 lb/hr OR 13
                                                                                [micro]g/dscm at 7-
                                                                                percent O2 for each
                                                                                new large tunnel kiln
                                                                                at facility.
Small tunnel kilns...................  .......................  .......................  2.0 E-04 lb/ton OR
(< 10 tph)...........................                                                     0.0011 lb/hr OR 70
                                                                                [micro]g/dscm at 7-
                                                                                percent O2 for each
                                                                                new small tunnel kiln
                                                                                at facility.
All tunnel kilns.....................  57 lb/hr HCl-equivalent  0.022 lb/ton PM OR
                                        for collection of all    0.0066 gr/dscf PM at 7-
                                        new tunnel kilns at      percent O2 OR 0.0032
                                        facility.                lb/hr non-Hg HAP
                                                                 metals for each new
                                                                 tunnel kiln at
                                                                 facility.
----------------------------------------------------------------------------------------------------------------

2. Work Practice Standards
    We are proposing work practice standards for BSCP periodic kilns in
lieu of HAP emission limits. The work practice standards would require
developing and using a designed firing time and temperature cycle for
each product produced in the periodic kiln; labeling each periodic kiln
with the maximum load (in tons) that can be fired in the kiln during a
single firing cycle; documenting the total tonnage placed in the kiln
for each load to ensure that it is not greater than the maximum load;
developing and implementing maintenance procedures for each kiln that
specify the frequency of inspection and maintenance; and developing and
maintaining records for each periodic kiln, including logs to document
the proper operation and maintenance procedures of the periodic kilns.
    We are also proposing work practice standards for BSCP tunnel kilns
in lieu of dioxin/furan emission limits. The

work practice standards would require maintaining and inspecting the
burners and associated combustion controls (as applicable); tuning the
specific burner type to optimize combustion; keeping records of each
burner tune-up; and submitting a report for each tune-up conducted.

E. What are the startup and shutdown requirements?

    The EPA's position on SSM events is discussed in section II.B of
this preamble. Standards for periods of startup and shutdown are
discussed in this section.
    We are proposing the work practice standards described in this
paragraph for periods of startup and shutdown for BSCP tunnel kilns
with APCD. For startup, the owner or operator would be required to vent
the exhaust from the kiln through the APCD by the time the kiln exhaust
temperature reaches 400 degrees Fahrenheit ([deg]F). In addition, no
bricks or other product may be introduced to the kiln until the kiln
exhaust temperature reaches 400[emsp14][deg]F and the exhaust is being
vented through the APCD. For shutdown, the owner or operator would be
required to vent the exhaust from the kiln through the APCD until the
kiln exhaust temperature falls below 300[emsp14][deg]F. In addition, no
bricks or other product may be put into the kiln once the kiln exhaust
temperature falls to 300[emsp14][deg]F and the exhaust is no longer
being vented through the APCD. When the kiln exhaust is being vented
through the APCD, the owner or operator would be required to comply
with the applicable continuous compliance requirements described in
section III.G of this preamble.
    We are proposing work practice standards for periods of startup and
shutdown for BSCP tunnel kilns without an APCD as well. For startup, no
bricks or other product may be introduced to the kiln until the kiln
exhaust temperature reaches 400[emsp14][deg]F. For shutdown, no bricks
or other product may be put into the kiln once the kiln exhaust
temperature falls to 300[emsp14][deg]F.

F. What are the testing and initial compliance requirements?

    We are proposing that owners or operators of all affected sources
subject to emission limits conduct an initial performance test using
specified EPA test methods to demonstrate initial compliance with all
applicable emission limits. A performance test would have to be
conducted before renewing the facility's 40 CFR part 70 operating
permit or at least every five years following the initial performance
test, as well as when an operating limit parameter value is being
revised.
    Under today's proposed BSCP manufacturing rule, the owner or
operator would have to measure emissions of HF, HCl, Cl2, Hg
and PM (or non-Hg HAP metals). We are proposing that the owner or
operator measure HF, HCl and Cl2 using one of the following
methods:

     EPA Method 26A, ``Determination of Hydrogen Halide and
Halogen Emissions from Stationary Sources--Isokinetic Method,'' 40
CFR part 60, appendix A-8;
     EPA Method 26, ``Determination of Hydrogen Chloride
Emissions from Stationary Sources,'' 40 CFR part 60, appendix A-8,
when no acid particulate (e.g., HF, HCl or Cl2 dissolved
in water droplets emitted by sources controlled by a wet scrubber)
is present;
     EPA Method 320, ``Measurement of Vapor Phase Organic
and Inorganic Emission by Extractive FTIR'' 40 CFR part 63, appendix
A, provided the test follows the analyte spiking procedures of
section 13 of Method 320, unless the owner or operator can
demonstrate that the complete spiking procedure has been conducted
at a similar source; or
     Any other alternative method that has been approved by
the Administrator under 40 CFR 63.7(f) of the General Provisions.

    Following the performance test, the owner or operator would
calculate the HCl-equivalent for the kiln using proposed Equation 2 in
40 CFR 63.8445(f)(2)(i). If there are multiple kilns at a facility, the
owner or operator would sum the HCl-equivalent for each kiln using
proposed Equation 3 in 40 CFR 63.8445(f)(2)(ii) to get the total
facility HCl-equivalent and compare this value to the proposed
limitation.
    If the owner or operator chooses to comply with one of the two PM
emission limits, we are proposing that the owner or operator measure PM
emissions using one of the following methods:

     EPA Method 5, ``Determination of Particulate Emissions
from Stationary Sources,'' 40 CFR part 60, appendix A-3;
     EPA Method 29, ``Determination of Metals Emissions From
Stationary Sources,'' 40 CFR part 60, appendix A-8, where the test
results would report the weight of the PM on the filter as PM
filterable; or
     Any other alternative method that has been approved by
the Administrator under 40 CFR 63.7(f) of the General Provisions.

    If the owner or operator chooses to comply with the non-Hg HAP
metals emission limit instead of one of the PM emission limits, the
owner or operator would measure non-Hg HAP metals emissions using EPA
Method 29 cited above or any other alternative method that has been
approved by the Administrator under 40 CFR 63.7(f) of the General
Provisions. The owner or operator may also use Method 29 or any other
approved alternative method to measure Hg emissions.
    The following paragraphs discuss the initial compliance
requirements that we are proposing. Prior to the initial performance
test, the owner or operator would need to install the continuous
parameter monitoring system (CPMS) equipment to be used to demonstrate
continuous compliance with the operating limits. During the initial
test, the owner or operator would use the CPMS to establish site-
specific operating parameter values that represent the operating
limits.
    For a DIFF or DLS/FF, we are proposing that the owner or operator
ensure that lime in the feed hopper or silo and to the APCD is free-
flowing at all times during the HF/HCl/Cl2 performance test
and record the feeder setting (on a per ton of fired product basis) for
the three test runs. If the lime feed rate varies, the owner or
operator would be required to determine the average feed rate from the
three test runs. The average of the three test runs establishes the
minimum site-specific feed rate operating limit. If there are different
average feed rate values during the PM/non-Hg HAP metals and HF/HCl/
Cl2 tests, the highest of the average values becomes the
site-specific operating limit. If a BLD system is present, the owner or
operator would need to submit analyses and supporting documentation
demonstrating conformance with EPA guidance and specifications for BLD
systems.
    For a stand-alone FF (i.e., no dry sorbent injection or DLS) and a
BLD system, we are proposing that the owner or operator submit analyses
and supporting documentation demonstrating conformance with EPA
guidance and specifications for BLD systems.
    For a dry limestone adsorber (DLA), we are proposing that the owner
or operator continuously measure the pressure drop across the DLA
during the HF/HCl/Cl2 performance test and determine the 3-
hour block average pressure drop. The average of the three test runs
establishes the minimum site-specific pressure drop operating limit.
Alternatively, the owner or operator may continuously monitor the
bypass stack damper position at least once every 15 minutes during the
performance test. The owner or operator also would need to maintain an
adequate amount of limestone in the limestone hopper, storage bin
(located at the top of the DLA) and DLA at all times. In addition, the
owner or operator would need to establish the limestone

feeder setting (on a per ton of fired product basis) 1 week prior to
the performance test and maintain the feeder setting for the 1-week
period that precedes the performance test and during the performance
test. Finally, the owner or operator would need to document the source
and grade of the limestone used during the performance test.
    For a wet scrubber, we are proposing that the owner or operator
continuously measure the scrubber pressure drop during the PM/non-Hg
HAP metals performance test, the scrubber liquid pH and chemical
addition rate (if applicable) during the HF/HCl/Cl2
performance test and the scrubber liquid flow rate during both the PM/
non-Hg HAP metals and HF/HCl/Cl2 performance tests. For each
wet scrubber parameter, the owner or operator would need to determine
and record the average values for the three test runs and the 3-hour
block average value. The average of the three test runs establishes the
minimum site-specific pressure drop, liquid pH, liquid flow rate and
chemical addition rate operating limits. If different average wet
scrubber liquid flow rate values are measured during the PM/non-Hg HAP
metals and HF/HCl/Cl2 tests, the highest of the average
values become the site-specific operating limit.
    For an activated carbon injection (ACI) system, we are proposing
that the owner or operator measure the activated carbon flow rate
during the Hg performance test and determine the 3-hour block average
flow rate. The average of the three test runs establishes the minimum
site-specific activated carbon flow rate operating limit.
    For a source with no APCD installed, we are proposing that the
owner or operator calculate the maximum potential HCl-equivalent using
proposed Equation 4 in 40 CFR 63.8445(g)(1)(i). The owner or operator
would use the results from the performance test to determine the
emissions at the maximum possible process rate. For example, if the
design capacity of the kiln is 10 tph and the production rate during
the performance test was 9 tph, then the test results represent 90
percent of the maximum potential emissions. If there are multiple kilns
at a facility, the owner or operator would need to sum the maximum
potential HCl-equivalent for each kiln to get the total facility
maximum potential HCl-equivalent and compare this value to the proposed
health-based emission limitation for acid gases. If the total facility
maximum potential HCl-equivalent is greater than the proposed
limitation, we are proposing that the owner or operator determine the
maximum process rate for which the total facility maximum potential
HCl-equivalent remains at or below the proposed limitation. If there
are multiple kilns, the owner or operator would need to determine one
or more combinations of maximum process rates that would result in a
total facility maximum potential HCl-equivalent remains at or below the
proposed limitation. The maximum process rate(s) would become the
operating limit(s) for process rate.

G. What are the continuous compliance requirements?

    Today's BSCP manufacturing rule proposes that the owner or operator
demonstrate continuous compliance with each emission limitation that
applies. The owner or operator would have to follow the requirements in
the operation, maintenance and monitoring (OM&M) plan and document
conformance with the OM&M plan. The owner or operator would need to
operate a CPMS to monitor the operating parameters established during
the initial performance test as described in the following paragraphs.
The CPMS would have to collect data at least every 15 minutes,
including at least three of four equally spaced data values (or at
least 75 percent if there are more than four data values per hour) per
hour to have a valid hour of data. The owner or operator would have to
operate the CPMS at all times when the process is operating. The owner
or operator would also have to conduct proper maintenance of the CPMS
(including inspections, calibrations and validation checks) and
maintain an inventory of necessary parts for routine repairs of the
CPMS. Using the recorded readings, the owner or operator would need to
calculate and record the 3-hour block average values of each operating
parameter. To calculate the average for each 3-hour averaging period,
the owner or operator would need to have at least 75 percent of the
recorded readings for that period.
    For a DIFF or DLS/FF, we are proposing that the owner or operator
demonstrate compliance with the acid gas (HF/HCl/Cl2)
health-based emission limit by maintaining free-flowing lime in the
feed hopper or silo and to the APCD at all times. If lime is not
flowing freely, according to load cell output, carrier gas/lime flow
indicator, carrier gas pressure drop measurement system or other
system, the owner or operator would have to promptly initiate and
complete corrective actions according to the OM&M plan. The owner or
operator would also have to maintain the feeder setting (on a per ton
of fired product basis) at or above the level established during the
HF/HCl/Cl2 performance test and record the feeder setting
once each shift.
    The proposed rule would provide the option to use either a BLD
system or VE monitoring to demonstrate compliance with the PM/non-Hg
HAP metals emission limit.
    For the option of a BLD system, we are proposing that the owner or
operator initiate corrective action within 1 hour of a BLD system alarm
and complete corrective actions according to the OM&M plan. The owner
or operator would also need to operate and maintain the FF such that
the alarm is not engaged for more than 5 percent of the total operating
time in a 6-month block reporting period. In calculating this operating
time fraction, the owner or operator would not count any alarm time if
inspection of the FF demonstrates that no corrective action is
required. If corrective action is required, the owner or operator must
count each alarm as a minimum of 1 hour. If corrective action is
initiated more than 1 hour after an alarm, the owner or operator must
count as alarm time the actual amount of time taken to initiate
corrective action.
    For the option of monitoring VE, we are proposing that the owner or
operator perform daily, 15-minute VE observations in accordance with
the procedures of EPA Method 22, ``Visual Determination of Fugitive
Emissions from Material Sources and Smoke Emissions from Flares,'' 40
CFR part 60, appendix A-7. During the VE observations, the kiln would
need to be operating under normal conditions. If VE are observed, the
owner or operator would have to promptly initiate and complete
corrective actions according to the OM&M plan. If no VE are observed in
30 consecutive daily EPA Method 22 tests, the owner or operator may
decrease the frequency of EPA Method 22 testing from daily to weekly
for that kiln stack. If VE are observed during any weekly test, the
owner or operator would have to promptly initiate and complete
corrective actions according to the OM&M plan and the owner or operator
would need to resume EPA Method 22 testing of that kiln stack on a
daily basis until no VE are observed in 30 consecutive daily tests, at
which time the owner or operator may again decrease the frequency of
EPA Method 22 testing to a weekly basis.
    For a stand-alone FF, we are proposing that the owner or operator
use a BLD system or monitor VE as described above to demonstrate
compliance with the PM/non-Hg HAP metals emission limit.

    For a DLA, we are proposing that the owner or operator demonstrate
compliance with the acid gas (HF/HCl/Cl2) health-based
emission limit by collecting and recording data documenting the DLA
pressure drop and reducing the data to 3-hour block averages. The owner
or operator would need to maintain the average pressure drop across the
DLA for each 3-hour block period at or above the average pressure drop
established during the HF/HCl/Cl2 performance test.
Alternatively, the owner or operator may continuously monitor the
bypass stack damper position at least once every 15 minutes during
normal kiln operation. Any period in which the bypass damper is opened
allowing the kiln exhaust gas to bypass the DLA would trigger
corrective actions according to the OM&M plan. The owner or operator
also would need to verify that the limestone hopper, storage bin
(located at the top of the DLA) and DLA contain an adequate amount of
limestone by performing a daily visual check of the limestone hopper
and the storage bin. A daily visual check could include one of the
following: (1) conducting a physical check of the hopper; (2) creating
a visual access point, such as a window, on the side of the hopper; (3)
installing a camera in the hopper that provides continuous feed to a
video monitor in the control room; or (4) confirming that load level
indicators in the hopper are not indicating the need for additional
limestone. If the hopper or storage bin does not contain adequate
limestone, the owner or operator would have to promptly initiate and
complete corrective actions according to the OM&M plan. The owner or
operator also would have to record the limestone feeder setting daily
(on a per ton of fired product basis) to verify that the feeder setting
is being maintained at or above the level established during the HF/
HCl/Cl2 performance test. The owner or operator also would
need to use the same grade of limestone from the same source as was
used during the HF/HCl/Cl2 performance test and maintain
records of the source and type of limestone. Finally, the owner or
operator would need to monitor VE, as described in the previous
paragraph.
    For a wet scrubber, we are proposing that the owner or operator
continuously maintain the 3-hour block averages for scrubber pressure
drop, scrubber liquid pH, scrubber liquid flow rate and chemical
addition rate (if applicable) at or above the minimum values
established during the applicable performance test. Maintaining the 3-
hour block average for scrubber pressure drop at or above the minimum
value established during the PM/non-Hg HAP metals performance test
would demonstrate compliance with the PM/non-Hg HAP metals emission
limit. Maintaining the 3-hour block average for scrubber liquid pH and
chemical (e.g., lime, caustic) addition rate at or above the minimum
values established during the HF/HCl/Cl2 performance test
would demonstrate compliance with the acid gas (HF/HCl/Cl2)
health-based emission limit. Maintaining the 3-hour block average for
scrubber liquid flow rate at or above the lowest minimum value
established during the PM/non-Hg HAP metals and HF/HCl/Cl2
performance tests would demonstrate compliance with all applicable
emission limits by showing that the scrubber is in proper working
order.
    For an ACI system, we are proposing that the owner or operator
demonstrate compliance with the Hg emission limit by continuously
monitoring the activated carbon flow rate and maintaining it at or
above the operating limit established during the Hg performance test.
    For sources with no APCD, we are proposing that the owner or
operator monitor VE as described above to demonstrate compliance with
the PM/non-Hg HAP metals emission limit. In addition, if the last
calculated total facility maximum potential HCl-equivalent was not at
or below the proposed health-based emission limitation for acid gases,
then we are proposing that the owner or operator collect and record
data documenting the process rate of the kiln and reduce the data to 3-
hour block averages. The owner or operator would need to maintain the
kiln process rate at or below the kiln process rate operating limit(s)
that would enable the total facility maximum potential HCl-equivalent
to remain at or below the proposed limitation.

H. What are the notification, recordkeeping and reporting requirements?

    All new and existing sources would be required to comply with
certain requirements of the General Provisions (40 CFR part 64, subpart
A), which are identified in proposed Table 8 of 40 CFR part 64, subpart
JJJJJ. The General Provisions include specific requirements for
notifications, recordkeeping and reporting.
    Each owner or operator would be required to submit a notification
of compliance status report, as required by 40 CFR 63.9(h) of the
General Provisions. This proposed BSCP manufacturing rule would require
the owner or operator to include in the notification of compliance
status report certifications of compliance with rule requirements.
Semiannual compliance reports, as required by 40 CFR 63.10(e)(3) of
subpart A, would also be required for each semiannual reporting period.
    This proposed BSCP manufacturing rule would require records to
demonstrate compliance with each emission limit and work practice
standard. These recordkeeping requirements are specified directly in
the General Provisions to 40 CFR part 63 and are identified in proposed
Table 8 of subpart JJJJJ.
    Specifically, we are proposing that the owner or operator keep the
following records:

     All reports and notifications submitted to comply with
this proposed BSCP manufacturing rule.
     Records of performance tests.
     Records relating to APCD maintenance and documentation
of approved routine control device maintenance exemption.
     Continuous monitoring data as required in this proposed
BSCP manufacturing rule.
     Records of BLD system alarms and corrective actions
taken.
     Records of each instance in which the owner or operator
did not meet each emission limit (i.e., deviations from operating
limits).
     Records of production rates.
     Records of approved alternative monitoring or testing
procedures.
     Records of maintenance and inspections performed on the
APCD.
     Current copies of the OM&M plan and records documenting
conformance.
     Logs of the information required to document compliance
with the periodic kiln work practice standard.
     Records of burner tune-ups used to comply with the
dioxin/furan work practice standard for tunnel kilns.
     Logs of the information required to document compliance
with the startup and shutdown work practice standards.
     Records of each malfunction and the corrective action
taken.

    We are also proposing that the owner or operator submit the
following reports and notifications:

     Notifications required by the General Provisions.
     Initial Notification no later than 120 calendar days
after the affected source becomes subject to this subpart.
     Notification of Intent to conduct performance tests
and/or other compliance demonstration at least 60 calendar days
before the performance test and/or other compliance demonstration is
scheduled.
     Notification of Compliance Status 60 calendar days
following completion of a compliance demonstration that includes a
performance test.
     Notification of Compliance Status 30 calendar days
following completion of a

compliance demonstration that does not include a performance test
(i.e., compliance demonstrations for the work practice standards).
     Compliance reports semi-annually, including a report of
the most recent burner tune-up conducted to comply with the dioxin/
furan work practice standard and a report of each malfunction
resulting in an exceedance and the corrective action taken.
     Results of each performance test within 60 days of
completing the test, submitted to the EPA by direct computer-to-
computer electronic transfer via EPA-provided software for data
collected using supported test methods.

I. How would I submit emissions test results to the EPA?

    In this proposal, the EPA is describing a process to increase the
ease and efficiency of performance test data submittal while improving
data accessibility. Specifically, the EPA is proposing that owners and
operators of BSCP manufacturing facilities submit electronic copies of
required performance test reports by direct computer-to-computer
electronic transfer using EPA-provided software. The direct computer-
to-computer electronic transfer is accomplished through the EPA's
Central Data Exchange (CDX) using the Compliance and Emissions Data
Reporting Interface (CEDRI). The CDX is the EPA's portal for submittal
of electronic data. The EPA-provided software is called the Electronic
Reporting Tool (ERT), which generates electronic reports of performance
tests and evaluations. The ERT report package will be submitted using
the CEDRI. The submitted report package will be stored in the CDX
archive (the official copy of record) and the EPA's public database
called WebFIRE. All stakeholders will have access to all reports and
data in WebFIRE via the WebFIRE Report Search and Retrieval link
(http://cfpub.epa.gov/webfire/index.cfm?action=fire.searchERTSubmission). A description and
instructions for use of the ERT can be found on the ERT Web site
(http://www.epa.gov/ttn/chief/ert/index.html), and CEDRI can be
accessed through the CDX Web site (www.epa.gov/cdx).
    The proposal to submit performance test data electronically to the
EPA applies only to those performance tests conducted using test
methods that are supported by the ERT at the time of the test. The ERT
supports most of the commonly used EPA reference methods. A listing of
the pollutants and test methods supported by the ERT is available on
the ERT Web site.
    We believe that the electronic submittal of reports increases the
usefulness of the data contained in those reports, is in keeping with
current trends in data availability and may ultimately result in less
burden on the regulated community. Electronic reporting can eliminate
paper-based, manual processes, thereby saving time and resources,
simplifying data entry, eliminating redundancies and providing data
quickly and accurately to the affected sources, air agencies, the EPA
and the public.
    By making data readily available, electronic reporting increases
the amount of data that can be used for the development of emission
factors. The EPA has received feedback from stakeholders asserting that
many of the EPA's emission factors are outdated or not representative
of a particular industry emission source. While the EPA believes that
the emission factors are suitable for their intended purpose, we also
recognize that emissions profiles on different pieces of equipment can
change over time due to a number of factors (fuel changes, equipment
improvements, industry work practices), and it is important for
emission factors to be updated to keep up with these changes. The EPA
is currently pursuing emission factor development improvements that
include procedures to incorporate the source test data that we are
proposing be submitted electronically.
    Emission factors are used in the development of emissions
inventories, and improved emission factors means that the quality of
these inventories will be improved more quickly than they would under
the current paper reporting requirements. Emissions inventories are
used for tracking emission trends and identifying potential sources of
emissions for reduction. For example, the EPA's National Air Toxics
Assessment (NATA) uses the EPA's National Emissions Inventory (NEI) in
its screening level assessments to characterize the nationwide chronic
cancer risk estimates and noncancer hazards from inhaling air toxics.
The NATA is used as a screening tool for air agencies to prioritize
pollutants, emission sources and locations of interest for further
study to gain a better understanding of risks. Therefore, improving the
quality of these inventories is an on-going goal for the agency and a
benefit to the public, air agencies and the regulated community.
    Additionally, the EPA, the regulated community and the public may
benefit from electronic reporting when the EPA conducts its CAA-
required technology and risk-based reviews. Because we will already
have access to these reports, our ability to do comprehensive reviews
will be increased and achieved within a shorter period of time. Under
an electronic reporting system, the EPA would have performance test
data in hand; thus, it is possible that fewer or less substantial
information collection requests (ICRs) in conjunction with prospective
CAA-required technology and risk-based reviews may be needed. This may
result in a decrease in the need for industry staff time to respond to
data collection requests. It may also allow the EPA to conduct these
required reviews more quickly, as we will not have to include the ICR
collection time in the process. While the regulated community may
benefit from reduced ICRs, the general public benefits from the
agency's ability to conduct these required reviews more quickly.
    Electronic reporting could minimize submission of unnecessary or
duplicative reports in cases where facilities report to multiple
government agencies and the agencies opt to rely on the EPA's
electronic reporting system to view report submissions. Where air
agencies continue to require a paper copy of these reports and will
accept a hard copy of the electronic report, facilities will have the
option to print paper copies of the electronic reporting forms to
submit to the air agencies, thus minimizing the time spent reporting to
multiple agencies. Additionally, maintenance and storage costs
associated with retaining paper records could likewise be minimized by
replacing those records with electronic records of electronically
submitted data and reports.
    There are benefits of information that is submitted in a
standardized format. Standardizing the reporting format will require
the reporting of specific data elements, thereby helping to ensure
completeness of the data and allowing for accurate assessment of data
quality. Additionally, imbedded quality assurance checks will perform
some of the required method calculations, reducing errors in test
reports. And because the system is entirely electronic, it eliminates
transcription errors in moving data from paper reports to data systems
for analysis. These quality assurance checks and procedures will
increase the accuracy of test report data, improve the overall quality
of test data, and lead to more accurate emission factors and higher
quality emissions inventories. These features benefit all users of the
data.
    Air agencies could benefit from more streamlined and automated
review of the electronically submitted data. For example, because the
performance test data would be readily-available in a standard
electronic format, air agencies

would be able to review reports and data electronically rather than
having to conduct a review of the reports and data manually. Having
reports and associated data in electronic format will facilitate review
through the use of software ``search'' options, as well as the
downloading and analyzing of data in spreadsheet format. Additionally,
air agencies would benefit from the reported data being accessible to
them through the EPA's electronic reporting system whenever they want
or need access (as long as they have access to the Internet). The
ability to access and review information electronically will assist air
agencies in more quickly determining compliance with emission
standards. This benefits both air agencies and the general public.
    The general public would also benefit from electronic reporting of
emissions data because the data would be available for viewing sooner
and would be easier for the public to access. The EPA Web site that
stores the submitted electronic data is easily accessible to the public
and provides a user-friendly interface that any stakeholder could
access.
    In summary, in addition to supporting regulation development,
control strategy development and other air pollution control
activities, having an electronic database populated with performance
test data would save industry, air agencies and the EPA significant
time, money and effort while also improving the quality of emission
inventories and air quality regulations.

IV. Rationale for the Proposed Rule for Brick and Structural Clay
Products Manufacturing

A. How did the EPA determine which sources would be regulated under the
proposed rule?

    In the BSCP manufacturing industry, the primary sources of HAP
emissions are kilns, including tunnel kilns and periodic kilns. The HAP
emitted from BSCP kilns include HF, HCl, Cl2, Hg and other
non-Hg HAP metals. At one time, dryers were a potential source of HF,
HCl, Cl2 and non-Hg HAP metals emissions, but the design and
operation of kilns and dryers has changed such that emissions released
from the heating of the raw materials and the products of combustion no
longer pass from the kiln into the dryer. In addition, the 2010 EPA
survey requested that owners/operators of specific dryers test for
dioxins/furans, and none of the tests found detectable levels of
dioxins/furans. See the technical memorandum ``Determination of ``Non-
Detect'' Test Data for the BSCP Proposed Rule'' in Docket ID No. EPA-
HQ-OAR-2013-0291. Other process units at BSCP manufacturing facilities
(e.g., raw material processing and handling) have not been found to
emit measurable quantities of HAP. For this reason, the proposed rule
covers existing and new kilns at major source BSCP manufacturing
facilities which meet the applicability criteria in the rule.
    BSCP kilns that do not meet the applicability criteria include
kilns that are used exclusively for setting glazes on previously fired
products. Nearly all of the acid gas emissions from the firing of BSCP
products are released during the initial firing, so kilns that are used
exclusively for setting glazes on previously fired products emit little
to no HF, HCl or Cl2.

B. How did the EPA select the format for the proposed rule?

    For Hg and total non-Hg HAP metals, this proposed BSCP
manufacturing rule provides owners and operators of regulated sources
with a choice between a numerical emission rate limit as a mass of
pollutant emitted per ton of bricks produced and a numerical emission
limit in units of concentration. The selection of numerical emission
rate limits and numerical emission limits as the format for this
proposed BSCP manufacturing rule provides flexibility for the regulated
community by allowing a regulated source to choose any control
technology or technique to meet the emission limits, rather than
requiring each unit to use a prescribed control method that may not be
appropriate in each case. In addition, the selection of numerical
emission rate limits as mass of pollutant emitted per ton of bricks
produced ensures that differences in kiln sizes or production rates do
not affect the level of emissions control achieved.
    The PM limits are proposed as a surrogate for non-Hg HAP metals.
The same control techniques that would be used to control PM will
control non-Hg HAP metals. Particulate matter was also chosen instead
of requiring control of specific individual HAP metals because all
kilns do not emit the same type and amount of HAP metals due to
differences in raw materials and fuels used to fire the kilns. However,
most kilns generally emit PM that includes some amount and combination
of HAP metals. The use of PM as a surrogate will also eliminate the
cost of performance testing needed to comply with numerous standards
for individual non-Hg HAP metals. We have used PM as a surrogate for
non-Hg HAP metals NESHAP for other rules with similar processes (e.g.,
Portland Cement Manufacturing, Lime Manufacturing).
    Although we continue to believe that PM is a good surrogate for
non-Hg HAP metals and that complying with a PM emission limit rather
than non-Hg HAP metals limits will be less costly for most kilns, we
understand that some owners and operators may find that meeting a total
non-Hg HAP metals limit is less costly than meeting a PM limit. To
provide that flexibility, we have developed an alternative compliance
option of a numerical emission rate limit for total non-Hg HAP metals
as a mass of pollutant emitted per hour. The ability to comply with
this limit would provide additional flexibility for small tunnel kilns
and tunnel kilns with a low metals content in the PM emissions and
would achieve equivalent emission reductions to the options to limit
PM.
    For acid gases (HF, HCl and Cl2), this proposed BSCP
manufacturing rule includes a health-based emission limit as a mass of
HCl-equivalent emitted per hour. Further discussion about the
development of the health-based standard for the proposed BSCP
manufacturing rule is provided in section IV.J of this preamble.
    This proposed BSCP manufacturing rule includes work practices for
dioxins/furans from tunnel kilns. As described in more detail in
section IV.K.2 of this preamble, 83 percent of the dioxin/furan data
collected during the ICR process were below the detection level and it
is not practicable due to technological and economic limitations to
apply measurement methodology to test for compliance with a numerical
limit.
    This proposed BSCP manufacturing rule also includes work practices
for periodic kilns. As described in more detail in section IV.K.1 of
this preamble, technological and economic limitations make it
impracticable to measure compliance with numerical emission limits for
BSCP periodic kilns.

C. How did the EPA consider different subcategories?

    Section 112(d)(1) of the CAA allows the EPA to promulgate emission
standards for either categories or subcategories of sources. Through
subcategorization, we are able to define subsets of similar emission
sources within a source category if differences in emissions
characteristics, processes or opportunities for pollution prevention
exist within the source category. Upon initial consideration of the
available information on the BSCP manufacturing industry, we determined
that separate subcategories for periodic kilns and tunnel kilns were
warranted

for several reasons. First, periodic kilns are smaller than tunnel
kilns (with lower production on an hourly basis, as well as accounting
for only about 4 percent of total BSCP industry production). Second,
periodic kilns are operated in batch cycles, whereas tunnel kilns
operate continuously. Third, periodic kilns are typically operated at
higher temperatures than tunnel kilns and products are typically heated
in the kiln for longer periods than products fired in tunnel kilns,
resulting in higher energy requirements. As noted in section IV.K.1 of
this preamble, we have determined that it is technologically and
economically infeasible to test periodic kilns, thereby ruling out a
quantitative analysis of how these differences impact emissions.
However, a qualitative comparison can be made, in that smaller kilns
operated periodically (i.e., periodic kilns) would be expected to have
lower emissions over time compared to the larger, continuously operated
tunnel kilns.
    We then examined the potential for additional subcategories for
tunnel kilns, including subcategorization based on kiln fuel and kiln
size. Based on the available emissions test data, we could not discern
differences in emissions based on fuel type. For that reason, we have
not subcategorized by fuel type. We request comment, including
additional data if appropriate, on whether we should subcategorize by
fuel type. In particular, we request comment on whether we should
create a subcategory for kilns fired with sawdust (with or without a
sawdust dryer).
    We then considered subcategorization of tunnel kilns based on kiln
size. There are several differences between the design, operation and
efficiency of larger kilns and smaller kilns. In particular, many small
kilns are the older, less efficient kilns in the industry and newer
kilns can be constructed to be larger and more efficient due to
advances in design. Smaller, older kilns were constructed with large
amounts of heavy refractory brick and are narrow and tall in shape,
with high arched ceilings. Larger, newer kilns can be constructed with
more efficient refractories and can include features such as fiber
linings and insulating brick, resulting in a wider kiln with lower
ceilings. In addition, the burners in a small kiln are generally less
efficient and are located near the bottom of the kiln, where some of
the heat is absorbed by the cars that move the bricks through the kiln
rather than by the bricks themselves. In a large kiln, the burners are
more efficient and are often located at the top of the kiln, where they
can fire downward to the product. Combined with the kiln size and shape
differences, the difference in burner efficiency and location results
in a more even temperature distribution throughout the kiln and product
in a large kiln than in a small kiln.
    To assess whether these design and operation differences have an
effect on emissions and provide support for defining size subcategories
in the proposed BSCP manufacturing rule, we conducted a set of
statistical analyses on the emissions dataset. In the vacated rule,
``small kilns'' were defined as kilns with a design capacity less than
10 tph and ``large kilns'' were defined as kilns with a design capacity
of 10 tph or greater. The main goal of the statistical analyses was to
determine if these definitions are supported by our current dataset.
Because we have Cl2, Hg and non-Hg HAP metals data for only
about 10 percent of the kilns in the industry, we conducted the series
analyses based on the HF, HCl and PM datasets, which are available for
a much larger percentage of the kilns in the industry, providing more
representative kiln datasets for the analyses.
    We found that the median of the emissions data from kilns in the
large kiln dataset was statistically different than the median of the
emissions data from kilns in the small kiln dataset for all three
pollutants. Also, based on a logistic model, we found high association
between emissions and the hypothesized design capacity classification.
Finally, we conducted a cluster analysis and considered all three
pollutants together to investigate whether the combined dataset
supported changing the definitions of small and large kilns. This
cluster analysis supported the subcategory definitions from the vacated
rule. (For more information on the statistical analyses, see ``Analysis
of Potential Subcategories for BSCP Tunnel Kilns'' in Docket ID No.
EPA-HQ-OAR-2013-0291.)
    Based on the above information and analyses, we determined that
differences in design and emissions exist between large (10 tph or
greater) and small (less than 10 tph) kilns. Therefore, we are
proposing to exercise our discretion to subcategorize based on kiln
size for these kilns' emissions of Hg. As discussed in section IV.D of
this preamble, we are not proposing to exercise our discretion to
subcategorize for other pollutants.

D. What approaches did the EPA consider in developing the proposed
emission limitations for existing and new sources?

    All standards established pursuant to CAA section 112(d)(2) must
reflect MACT, the maximum degree of reduction in emissions of air
pollutants that the Administrator, taking into consideration the cost
of achieving such emissions reductions and any nonair quality health
and environmental impacts and energy requirements, determined is
achievable for each category.
    For existing sources, MACT cannot be less stringent than the
average emission limitation achieved by the best performing 12 percent
of existing sources for categories and subcategories with 30 or more
sources or the best performing five sources for subcategories with less
than 30 sources. This requirement constitutes the MACT floor for
existing sources. The CAA specifies that MACT for new sources shall not
be less stringent than the emission control that is achieved in
practice by the best controlled similar source. This minimum level of
stringency is the MACT floor for new units.
    The EPA may not consider costs or other impacts in determining the
MACT floor. However, the EPA must consider cost, nonair quality health
and environmental impacts and energy requirements in connection with
any standards that are more stringent than the MACT floor (beyond-the-
floor controls).
    The remainder of this section describes the development of the pool
of data used to calculate the MACT floors for Hg and PM (as a surrogate
for non-Hg HAP metals). As noted in section IV.J of this preamble,
health-based emissions standards are being proposed for the acid gases
HF, HCl and Cl2 under the provisions of CAA section
112(d)(4). Consequently, the EPA has not prepared a MACT floor analysis
for these pollutants.
1. Mercury
    In our MACT floor analysis for Hg, we separated the sources into
large kiln and small kiln subcategories, as described in section IV.C
of this preamble. For each subcategory, we ranked the sources based on
the data in terms of lb/ton (as described in section IV.E of this
preamble) and identified the best performing 12 percent of sources.
Once we identified the best performing kilns, we then calculated the
MACT floor in units of lb/ton for each subcategory as described in
section IV.E of this

preamble. We also calculated the MACT floor in lb/hr and concentration
units ([mu]g/dscm at 7-percent O2) for each subcategory,
based on the concentration emissions data for the same top 12 percent
(best performing) sources as the lb/ton floor. This is further
discussed in section IV.E of this preamble and in the technical
memorandum ``Maximum Achievable Control Technology (MACT) Floor
Analysis for Brick and Structural Clay Products'' in Docket ID No. EPA-
HQ-OAR-2013-0291.
2. Total Non-Hg HAP Metals
    We developed MACT floors for PM as a surrogate for total non-Hg HAP
metals. The available PM data show that kilns controlled with a FF-
based APCD (e.g., DIFF, DLS/FF) as a group are better performers than
kilns without FF-based controls. When we divided the kilns into two
groups, one group consisting of kilns with a FF-based APCD and the
other group consisting of uncontrolled kilns and kilns with a different
type of APCD, we found that the test data for kilns with FF-based APCD
showed they were consistently good performers, while the test data for
kilns without a FF-based APCD varied widely. The worst performing kiln
with a FF-based APCD performs better than the average kiln in the group
without a FF-based APCD. The best performing 75 percent of the kilns
with a FF-based APCD showed better performance than 80 percent of the
kilns without a FF-based APCD. We also conducted a t-test on the
averages of the two groups and we found that the average of the test
data for kilns with FF-based APCD was statistically different from the
average of the test data for kilns without a FF-based APCD (with 99-
percent confidence). See the technical memorandum ``Analysis of
Potential Subcategories in the BSCP Source Category'' in Docket ID No.
EPA-HQ-OAR-2013-0291.
    One consequence of the wide variability in emissions from kilns
without a FF-based APCD is that there are a few uncontrolled kilns and
kilns controlled with DLA with lower lb/ton emissions than some of the
kilns controlled with a FF-based APCD. We understand that that the
emissions from kilns with FF-based APCD will be consistently low over
time, based on the design of these APCD and years of experience with
these devices. On the other hand, we do not have multiple tests over
time that would enable us to say the same for kilns that have a
different type of APCD (e.g., DLA) or are uncontrolled. Thus, we are
requesting information and analysis as to whether the data showing low
emissions from some kilns without a FF-based APCD are reliable.\1\
---------------------------------------------------------------------------

    \1\ Further, as discussed in section IV.P.1 of this preamble,
the EPA is also considering setting emission limits for PM and total
non-Hg HAP metals based on the top 12 percent of the data available
in each of the kiln size subcategories. The reliability of the data
showing low emissions from some kilns without a FF-based APCD is a
key factor in the EPA's determination of which approach is
appropriate.
---------------------------------------------------------------------------

    As of January 1, 2014, there were 225 operating BSCP tunnel kilns
in the industry (including kilns at major sources and synthetic area
sources); the top 12 percent of the kilns in the industry would be
represented by the 27 best performing kilns. Therefore, we ranked the
kilns with a FF-based APCD in terms of lb/ton (as described in section
IV.E of this preamble) and identified the 27 best performing sources
from that group. Once we identified the best performing kilns, we then
calculated the MACT floor in units of lb/ton as described in section
IV.E of this preamble. We also calculated the MACT floor in
concentration units (gr/dscf at 7-percent O2), based on the
concentration emissions data for the same top 12 percent (best
performing) sources as the lb/ton floor. As another alternative, we
calculated an equivalent lb/hr total non-Hg HAP metals limit using the
average non-Hg HAP metals content of the PM emissions and the average
process rates of the best performing kilns. This limit would provide
additional compliance flexibility for small tunnel kilns and tunnel
kilns with a low metals content in the PM emissions. The alternatives
are further discussed in section IV.E of this preamble and in the
technical memorandum ``Maximum Achievable Control Technology (MACT)
Floor Analysis for Brick and Structural Clay Products'' in Docket ID
No. EPA-HQ-OAR-2013-0291.

E. How did the EPA determine the MACT floors for existing sources?

    The EPA must consider available emissions information to determine
the MACT floors. The EPA must exercise its judgment, based on an
evaluation of the relevant factors and available data, to determine the
level of emissions control that has been achieved by the best
performing sources under variable conditions. The United States Court
of Appeals for the District of Columbia Circuit has recognized that the
EPA may consider variability in estimating the degree of emission
reduction achieved by best performing sources and in setting MACT
floors. See Mossville Envt'l Action Now v. EPA, 370 F.3d 1232, 1241-42
(D.C. Cir. 2004) (holding EPA may consider emission variability in
estimating performance achieved by best performing sources and may set
the floor at level that best performing source can expect to meet
``every day and under all operating conditions'').
    As discussed in section IV.D of this preamble, the EPA established
the MACT floors for PM (as a surrogate for non-Hg HAP metals) for BSCP
kilns based on sources representing 12 percent of the number of sources
in the category. For Hg emitted from each of the kiln subcategories,
the EPA established the MACT floors based on sources representing 12
percent of the sources for which we had emissions information. The MACT
floor limitations for Hg and PM (as a surrogate for total non-Hg HAP
metals) were calculated based on the performance of the best performing
sources in each of the subcategories. The best performing sources were
determined by ranking each source's average emission value from lowest
to highest.
    Once the best performing sources in the MACT floor pools were
identified, the MACT floors were calculated using an Upper Prediction
Limit (UPL). The UPL takes into consideration the average performance
of the units in the MACT floor pool and the variability of the test
runs during the testing conditions. For more information regarding the
general use of the UPL and why it is appropriate for calculating MACT
floors, see the memorandum ``Use of the Upper Prediction Limit for
Calculating MACT Floors'' in Docket ID No. EPA-HQ-OAR-2013-0291.
    The UPL represents the value which one can expect the mean of a
specified number of future observations (e.g., 3-run average) to fall
below for the specified level of confidence, based upon the results of
an independent sample from the same population. A prediction interval
for a future observation or an average of future observations, is an
interval that will, with a specified degree of confidence, contain the
next (or the average of some other pre-specified number of) randomly
selected observation(s) from a population. Given this definition, the
UPL represents the value which we can expect the mean of three future
observations (3-run average) to fall below, based upon the results of
an independent sample from the same population. In other words, if we
were to randomly select a future test condition from any of these
sources (i.e., average of three runs), we can be 99 percent confident
that the reported level will fall at or below the UPL value.

    There are different UPL equations depending on the distribution of
the data (e.g., normal, lognormal, skewed/unknown). We first determined
the distribution of each MACT floor pool's data to determine the
appropriate UPL equation using statistical tests of the kurtosis (K),
standard error of kurtosis (SEK), skewness (S) and standard error of
skewness (SES). The skewness statistic (S) characterizes the degree of
asymmetry of a given dataset. According to the skewness hypothesis
test, if S is less than two times the SES, the data distribution can be
considered to be normal. The kurtosis statistic (K) characterizes the
degree of peakedness or flatness of a given data distribution in
comparison to a normal distribution. According to the kurtosis
hypothesis test, if K is less than two times the SEK, the data
distribution can be considered to be normal. The skewness and kurtosis
hypothesis tests were applied to both the reported test values and the
log-transformed values of the reported test values to determine the
distribution of each dataset. A UPL was then calculated for each MACT
floor pool with the UPL equation corresponding to the dataset's
distribution (e.g., normal, lognormal, skewed/unknown).
    A more detailed explanation of all the UPL equations used,
including the calculations of kurtosis, standard error of kurtosis,
skewness and standard error of skewness, can be found in the technical
memorandum ``Maximum Achievable Control Technology (MACT) Floor
Analysis for Brick and Structural Clay Products'' in Docket ID No. EPA-
HQ-OAR-2013-0291.
    Test method measurement imprecision can also be a component of data
variability. Of particular concern are those data that are reported
near or below a test method's pollutant detection capability. There is
a concern that a floor emissions limit calculated using values at or
near the method detection limit may not account adequately for data
measurement variability. The expected measurement imprecision for an
emissions value occurring at or near the detection limit is about 40 to
50 percent. Relative pollutant measurement imprecision decreases to a
consistent 10 to 15 percent for values measured at a level about 3
times the method detection limit.\2\
---------------------------------------------------------------------------

    \2\ American Society of Mechanical Engineers, Reference Method
Accuracy and Precision (ReMAP): Phase 1, Precision of Manual Stack
Emission Measurements, CRTD Vol. 60, February 2001.
---------------------------------------------------------------------------

    One approach that we believe could be applied to account for
measurement variability would require defining a detection limit that
is representative of the data used in establishing the floor emissions
limitations and also minimizes the influence of an outlier test-
specific method detection limit value. The EPA has developed a list of
representative detection levels (RDL) developed from available
pollutant specific method detection levels.\3\ These RDL values are
then multiplied by three to decrease measurement imprecision to around
10 to 15 percent (as noted in the previous paragraph), resulting in
values referred to as ``3xRDL'' values.
---------------------------------------------------------------------------

    \3\ ``Data and procedure for handling below detection level data
in analyzing various pollutant emissions databases for MACT and RTR
emissions limits.'' Memorandum from Peter Westlin, SPPD, MPG and
Raymond Merrill, AQAD, MTG, to SPPD management and MACT rule
writers. December 13, 2011.
---------------------------------------------------------------------------

    The appropriate 3xRDL value was compared to the calculated UPL
value for each pollutant and subcategory. If the 3xRDL value was less
than the calculated UPL value, we concluded that measurement
variability is adequately addressed and we used the calculated UPL
value as the MACT floor emissions limit. If, on the other hand, the
3xRDL value was greater than the calculated UPL value, we concluded
that the calculated UPL value does not account entirely for measurement
variability. We then used the 3xRDL value in place of the calculated
UPL value to ensure that measurement variability is adequately
addressed in the MACT floor emissions limit. This check was part of the
variability analysis for all existing MACT floors that had below
detection limit (BDL) or detection level limited (DLL) run data present
in the best performing datasets (see the technical memorandum ``Maximum
Achievable Control Technology (MACT) Floor Analysis for Brick and
Structural Clay Products'' in Docket ID No. EPA-HQ-OAR-2013-0291).
    As previously discussed, we accounted for variability in setting
floors, not only because variability is an element of performance, but
because it is reasonable to assess best performance over time. For
example, we know that the HAP emission data from the best performing
units are, for the most part, short-term averages and that the actual
HAP emissions from those sources will vary over time. If we do not
account for this variability, we would expect that even the units that
perform better than the floor on average could potentially exceed the
floor emission levels a part of the time, which would mean that
variability was not properly taken into account. This variability may
include the day-to-day variability in the total HAP input to each unit;
variability of the sampling and analysis methods; and variability
resulting from site-to-site differences for the best performing units.
The EPA's consideration of variability accounted for that variability
exhibited by the data representing multiple units and multiple data
values for a given unit (where available). We calculated the MACT floor
based on the UPL (upper 99th percentile) as described earlier from the
average performance of the best performing units and the variability of
the best performing units.
    We believe this approach reasonably ensures that the emission
limits selected as the MACT floors adequately represent the level of
emissions actually achieved by the average of the units in the top 12
percent, considering operational variability of those units. Both the
analysis of the measured emissions from units representative of the top
12 percent and the variability analysis are reasonably designed to
provide a meaningful estimate of the average performance or central
tendency, of the best performing 12 percent of units in a given
subcategory. A detailed discussion of the MACT floor methodology is
presented in the technical memorandum ``Maximum Achievable Control
Technology (MACT) Floor Analysis for Brick and Structural Clay
Products'' in Docket ID No. EPA-HQ-OAR-2013-0291.
    Table 5 of this preamble presents the average emission level of the
best performing sources and the existing source MACT floor. For this
source category, all the existing source MACT floors are based on the
UPL.

        Table 5--Summary of MACT Floor Results for Brick and Structural Clay Products Existing Sources a
----------------------------------------------------------------------------------------------------------------
            Subcategory                     Parameter                Hg \b\                     PM b c
----------------------------------------------------------------------------------------------------------------
Large tunnel kilns (>= 10 tph).....  Avg. of best            1.6 E-05 lb/ton.......
                                      performing sources.    1.7 E-04 lb/hr........
                                                             14 [mu]g/dscm.........
                                     MACT floor............  2.2 E-05 lb/ton.......
                                                             2.7 E-04 lb/hr........
                                                             29 [mu]g/dscm.........
Small tunnel kilns (< 10 tph)......  Avg. of best            1.8 E-04 lb/ton.......
                                      performing sources.    0.0010 lb/hr..........
                                                             62 [mu]g/dscm.........
                                     MACT floor............  2.0 E-04 lb/ton.......
                                                             0.0011 lb/hr..........
                                                             70 [mu]g/dscm.........
All kilns..........................  Avg. of best            ......................  0.041 lb/ton.
                                      performing sources.                            0.011 gr/dscf.
                                     MACT floor............  ......................  0.16 lb/ton.
                                                                                0.040 gr/dscf.
----------------------------------------------------------------------------------------------------------------
\a\ For this source category, all the existing source MACT floors are based on the UPL.
\b\ Concentration units are at 7-percent O2.
\c\ PM is a surrogate for non-Hg HAP metals.

F. How did the EPA determine the MACT floors for new sources?

    The approach that we used to calculate the MACT floors for new
sources is somewhat different from the approach that we used to
calculate the MACT floors for existing sources because the statutory
standard is different. Although the MACT floors for existing units are
intended to reflect the performance achieved by the average of the best
performing 12 percent of sources, the MACT floors for new units are
meant to reflect the emission control that is achieved in practice by
the best controlled similar source. Thus, for existing units, we are
concerned about estimating the central tendency of a set of multiple
units, whereas for new units, we are concerned about estimating the
level of control that is representative of that achieved by a single
best performing source. As with the analysis for existing sources, the
new source analysis must account for variability.
    Similar to the MACT floor process used for existing units, the
approach we used for determining the MACT floor for new units was based
on available emissions test data. Specifically, we calculated the new
source MACT floor for a subcategory of sources by ranking each unit's
average emission value within the subcategory from lowest to highest to
identify the best performing similar source. The new source MACT floor
limits for Hg and PM (as a surrogate for total non-Hg HAP metals) were
calculated based on the performance of the best performing source for
each pollutant in each of the subcategories.
    The MACT floor limits for new sources were calculated using the
same UPL formula as was used for existing sources, except the data used
were from the best performing source rather than the best performing 12
percent of sources. As previously discussed, we accounted for
variability of the best performing source in setting floors, not only
because variability is an element of performance, but because it is
reasonable to assess best performance over time. We calculated the new
source MACT floor based on the UPL (upper 99th percentile) as described
earlier from the average performance of the best performing similar
source, Student's t-factor and the total variability of the best
performing source.
    This approach reasonably ensures that the emission limit selected
as the MACT floor for new sources adequately represents the average
level of control achieved in practice by the best controlled similar
source, considering ordinary operational variability. A detailed
discussion of the MACT floor methodology is presented in the technical
memorandum ``Maximum Achievable Control Technology (MACT) Floor
Analysis for Brick and Structural Clay Products'' in Docket ID No. EPA-
HQ-OAR-2013-0291.
    Table 6 of this preamble presents, for each subcategory and
pollutant, the average emission level of the best performing similar
source and the new source MACT floor. The new source MACT floors are
based on the UPL unless otherwise noted.

           Table 6--Summary of MACT Floor Results for Brick and Structural Clay Products New Sources a
----------------------------------------------------------------------------------------------------------------
            Subcategory                   Parameter               Hg \b\                      PM b c
----------------------------------------------------------------------------------------------------------------
Large tunnel kilns (>= 10 tph)....  Avg. of top performer  1.5 E-05 lb/ton.....
                                                           1.8 E-04 lb/hr......
                                                           10 [mu]g/dscm.......
                                    MACT floor...........  2.0 E-05 lb/ton.....
                                                           2.4 E-04 lb/hr......
                                                           13 [mu]g/dscm.......
Small tunnel kilns (< 10 tph).....  Avg. of top performer  1.8 E-04 lb/ton.....
                                                           0.0010 lb/hr........
                                                           62 [mu]g/dscm.......
                                    MACT floor...........  2.0 E-04 lb/ton.....
                                                           0.0011 lb/hr........
                                                           70 [mu]g/dscm.......
All kilns.........................  Avg. of top performer  ....................  0.0060 lb/ton.
                                                                                0.0020 gr/dscf.

                                    MACT floor...........  ....................  0.022 lb/ton \d\.
                                                                                0.0066 gr/dscf \d\.
----------------------------------------------------------------------------------------------------------------
\a\ The new source MACT floors are based on the UPL unless otherwise noted.
\b\ Concentration units are at 7 percent O2.
\c\ PM is a surrogate for non-Hg HAP metals.
\d\ The MACT floor is based on the 3xRDL value.

G. What is our approach for applying the upper prediction limit to
limited datasets?

    In a recent United States Court of Appeals for the District of
Columbia Circuit decision in National Association of Clean Water
Agencies v. EPA, which involved challenges to EPA's MACT standards for
sewage sludge incinerators, questions were raised regarding the
application of the UPL to limited datasets. We have since addressed
these questions, as explained in detail in the memorandum titled,
``Approach for Applying the Upper Prediction Limit to Limited
Datasets'' (hereafter referred to as the ``Limited Dataset Memo''),
which is available in Docket ID No. EPA-HQ-OAR-2013-0291.
    A limited dataset is defined as having less than seven data points.
In calculating MACT floor limits based on limited datasets, we
considered additional factors as described in the Limited Dataset Memo.
We seek comments on the approach described in the Limited Dataset Memo
and whether there are other approaches we should consider for such
datasets. We also seek comments on the application of this approach for
the derivation of MACT limits based on limited datasets in this
proposal, which are described in the Limited Dataset Memo.
    For the BSCP manufacturing source category, we have limited
datasets for the following pollutants and subcategories: Hg for
existing and new small tunnel kilns; PM for new tunnel kilns; and Hg
for new large tunnel kilns. For each dataset, we performed the steps
outlined in the Limited Dataset Memo. See the Limited Dataset Memo for
more information.

H. How did the EPA consider beyond-the-floor for existing sources?

    As discussed in sections II.A and IV.D of this preamble, the EPA
must consider emissions limitations and requirements that are more
stringent than the MACT floor (i.e., beyond-the-floor options). When
considering beyond-the-floor options, the EPA must consider not only
the maximum degree of reduction in emissions of HAP, but must take into
account the associated costs, energy and non-air quality health and
environmental impacts.
    Once the MACT floor determinations were complete for each
subcategory, we considered regulatory options more stringent than the
MACT floor level of control (e.g., the performance of technologies that
could result in lower emissions) for the different subcategories. We
considered requiring all existing sources to meet the new source MACT
floors for Hg and PM (as a surrogate for total non-Hg HAP metals)
developed as described in section IV.F of this preamble. We analyzed
the beyond-the-floor options for Hg and total non-Hg HAP metals
separately for existing sources. Our analyses are documented in the
technical memorandum, ``Development of Cost and Emission Reduction
Impacts for the BSCP NESHAP,'' in Docket ID No. EPA-HQ-OAR-2013-0291.
    The beyond-the-floor option for total non-Hg HAP metals is
estimated to achieve additional non-Hg HAP metals reductions of 2.86
tpy and cost an additional $22.8 million per year (2011 dollars), for a
cost effectiveness of $7,960,000 per ton of total additional non-Hg HAP
metals removed. The beyond-the-floor option for Hg is estimated to
achieve additional Hg reductions of 0.0625 tpy (125 pounds per year)
and cost an additional $9.25 million per year (2011 dollars), for a
cost effectiveness of $148,000,000 per ton of total additional Hg
removed ($74,000 per pound of additional Hg removed). We have concluded
that the incremental costs of additional control beyond the MACT floor
emission limits are not reasonable relative to the level of emission
reduction achieved for either the Hg or total non-Hg HAP metals beyond-
the-floor options. Therefore, we are not proposing beyond-the-floor
limits for Hg or total non-Hg HAP metals.

I. How did the EPA consider beyond-the-floor for new sources?

    The MACT floor level of control for new tunnel kilns for each
pollutant was based on the emission control that is achieved in
practice by the best controlled similar source within each of the
subcategories. A new kiln would likely need both a FF and ACI system
for control of non-Hg HAP metals and Hg to meet the new source MACT
floors. When we establish a beyond-the-floor standard, we typically
identify control techniques that have the ability to achieve an
emissions limit more stringent than the MACT floor. No techniques were
identified that would achieve HAP reductions greater than the new
source floors for the subcategories. Therefore, the EPA is not
proposing a beyond-the-floor limit for new sources in this proposed
BSCP manufacturing rule.

J. How did the EPA determine whether to set health-based standards for
existing and new sources?

    In developing the proposed BSCP manufacturing rule, we considered
whether it was appropriate to establish health-based emission standards
under CAA section 112(d)(4) for the acid gases HF, HCl and
Cl2. As a general matter, CAA section 112(d) requires MACT
standards at least as stringent as the MACT floor to be set for all HAP
emitted from major sources. However, CAA section 112(d)(4) provides
that for HAP with established health thresholds, the EPA has the
discretionary authority to consider such health thresholds when
establishing emission standards under CAA section 112(d). This
provision is intended to allow the EPA to establish emission standards
other than technology-based MACT standards, in cases where an
alternative emission standard will still ensure that the health
threshold will not be exceeded, with an ample margin of safety. This
section discusses the prerequisite for setting a CAA section 112(d)(4)
standard, the factors the EPA considered in exercising its discretion
to set a CAA section 112(d)(4) standard and how the EPA set the level
of the proposed standard.

1. What Are the Prerequisites for Setting a CAA Section 112(d)(4)
Standard?
    The prerequisites for setting a CAA section 112(d)(4) standard are
that the pollutant must have a health threshold and not be
carcinogenic.\4\ Whether a pollutant has a health threshold is based on
certain factors, including evidence and classification of carcinogenic
risk and evidence of noncarcinogenic effects: \5\
---------------------------------------------------------------------------

    \4\ See Portland Cement NESHAP Final Rule, 75 FR 54970, 54985
(col. 2-3) (September 9, 2010) (``In order to exercise this
discretion [to set health threshold standards under 112(d)(4)], EPA
must first conclude that the HAP at issue has an established health
threshold . . .'').
    \5\ See Pulp and Paper Chemical Recovery Combustion Sources
NESHAP Proposed Rule, 63 FR 18754, 18766/1-18767/1 (April 15, 1998).

     The EPA ``presumptively concludes'' that known,
probable and possible carcinogens (Group A, B and C pollutants)
``should not be categorized as threshold pollutants.''
     Pollutants for which there is not enough evidence to
make a conclusion on carcinogenicity (Group D pollutants) will be
evaluated on a case-by-case basis.
     Pollutants classified as non-carcinogens (Group E
pollutants) are ``presumptively considered'' to be threshold
pollutants.\6\
---------------------------------------------------------------------------

    \6\ The current weight-of-evidence under the 2005 EPA Guidelines
for Carcinogen Risk Assessments, which replaced the 1986 cancer
guidelines, recommends the following cancer hazard descriptors:
``Carcinogenic to Humans,'' ``Likely to Be Carcinogenic to Humans,''
``Suggestive Evidence of Carcinogenic Potential,'' ``Inadequate
Information to Assess Carcinogenic Potential,'' and ``Not Likely to
Be Carcinogenic to Humans'' (which are considered equivalent to the
1986 groups A, B, C, D and E respectively).

Health threshold standards may not be set for pollutants that are
carcinogenic.\7\
---------------------------------------------------------------------------

    \7\ See Pulp and Paper Chemical Recovery Combustion Sources
NESHAP Proposed Rule, 63 FR 18754, 18765/3 (``The EPA presumptively
applies section 112(d)(4) only to HAP's that are not carcinogens
because Congress clearly intended that carcinogens be considered
nonthreshold pollutants'').