[Federal Register Volume 78, Number 29 (Tuesday, February 12, 2013)]
[Rules and Regulations]
[Pages 10005-10054]
[FR Doc No: 2012-31633]

Vol. 78

Tuesday,

No. 29

February 12, 2013

Part II

Environmental Protection Agency

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40 CFR Parts 60 and 63

National Emission Standards for Hazardous Air Pollutants for the
Portland Cement Manufacturing Industry and Standards of Performance for
Portland Cement Plants; Final Rule

Federal Register / Vol. 78 , No. 29 / Tuesday, February 12, 2013 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[EPA-HQ-OAR-2011-0817; FRL-9758-6]
RIN 2060-AQ93

National Emission Standards for Hazardous Air Pollutants for the
Portland Cement Manufacturing Industry and Standards of Performance for
Portland Cement Plants

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: On July 18, 2012, the EPA proposed amendments to the National
Emission Standards for Hazardous Air Pollutants for the Portland Cement
Manufacturing Industry and the Standards of Performance for Portland
Cement Plants. This final action amends the national emission standards
for hazardous air pollutants for the Portland cement industry. The EPA
is also promulgating amendments with respect to issues on which it
granted reconsideration on May 17, 2011. In addition, the EPA is
amending the new source performance standard for particulate matter.
These amendments promote flexibility, reduce costs, ease compliance and
preserve health benefits. The amendments also address the remand of the
national emission standards for hazardous air pollutants for the
Portland cement industry by the United States Court of Appeals for the
District of Columbia Circuit on December 9, 2011. Finally, the EPA is
setting the date for compliance with the existing source national
emission standards for hazardous air pollutants to be September 9,
2015.

DATES: This final rule is effective on February 12, 2013. The EPA is
setting the compliance date for existing open clinker storage piles to
be February 12, 2014.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2011-0817. All documents in the docket are
listed in the http://www.regulations.gov Web site. Although listed in
the index, some information is not publicly available, for example,
confidential business information or other information whose disclosure
is restricted by statute. Certain other material, such as copyrighted
material, will be publicly available only in hard copy. Publicly
available docket materials are available either electronically in
www.regulations.gov or in hard copy at the EPA Docket Center, EPA 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<PHONE_NUMBER>, and the telephone number for the Docket
Center is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: For questions about this final action,
contact Ms. Sharon Nizich, Office of Air Quality Planning and
Standards; Sector Policies and Programs Division, Minerals and
Manufacturing Group (D243-04); Environmental Protection Agency;
Research Triangle Park, NC 27111; telephone number:<PHONE_NUMBER>; fax
number:<PHONE_NUMBER>; email address<EMAIL_ADDRESS>For
information about the applicability of the NESHAP or NSPS contact Mr.
Patrick Yellin, Monitoring, Assistance and Media Programs Division
(2227A), Office of Enforcement and Compliance Assurance, U.S.
Environmental Protection Agency, 1200 Pennsylvania Avenue, Washington,
DC 20460; telephone number<PHONE_NUMBER>; email address
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Acronyms and Abbreviations. The following acronyms and
abbreviations are used in this document.

APCD air pollution control devices
CAA Clean Air Act
CBI confidential business information
CDX Central Data Exchange
CEMS continuous emission monitoring systems
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CISWI commercial and industrial solid waste incinerators
CMS continuous monitoring system
COMS continuous opacity monitoring system
CO2 carbon dioxide
CPMS continuous parametric monitoring system
D/F dioxins and furans
EPA Environmental Protection Agency
ESP Electrostatic Precipitators
ERT Electronic Reporting Tool
FR Federal Register
gr/dscf grains per dry standard cubic foot
HAP hazardous air pollutants
Hg mercury
HCl hydrogen chloride
ICR information collection request
Lb/ton pound per ton
MACT maximum achievable control technology
meHg methylmercury
NAICS North American Industry Classification System
NAS National Academy of Science
NESHAP National Emissions Standards for Hazardous Air Pollutants
NHSM Nonhazardous Secondary Materials
NOX Nitrogen Oxides
NRC National Research Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
oHAP Non-dioxin organic hazardous air pollutants
OMB Office of Management and Budget
PCA Portland Cement Association
PM particulate matter
ppm(v) (d,w) parts per million (by volume) (dry, wet)
RATA Relative Accuracy Test Audit
RfD reference dose
RIA regulatory impact analysis
RTC Response to Comment
RTO regenerative thermal oxidizers
SIP state implementation plan
SO2 Sulphur Dioxide
THC total hydrocarbons
tpy tons per year
TTN Technology Transfer Network
[micro]g/m3 micrograms per cubic meter
UPL Upper Prediction Limit
UMRA Unfunded Mandates Reform Act
TEOM Tapered Element Oscillating Microbalance
VCS voluntary consensus standards
WWW worldwide web

    Background Information Document. On July 18, 2012 (77 FR 42368),
the EPA proposed to amend the Portland cement manufacturing industry
NESHAP and the Portland cement plant new source performance standards
(NSPS). In this action, we are taking final action on this proposal. A
summary of the public comments on the proposal and the EPA's responses
to those comments is available in Docket ID Number EPA-HQ-OAR-2011-
0817.
    Organization of this Document. The information presented 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?
    D. Judicial Review
II. Background Information
    A. What is the statutory authority for these amendments?
    B. What actions preceded this final rule?
III. Summary of Final Amendments to Subpart LLL and Subpart F
    A. Reconsideration of Standards
    B. Continuously Monitored Parameters for Alternative Organic HAP
Standard (With THC Monitoring Parameter)
    C. Allowing Sources With Dry Caustic Scrubbers To Comply With
HCl Standard Using Performance Tests
    D. Alternative PM Limit
    E. Coal Mills
    F. NESHAP Compliance Date Extension for Existing Sources
    G. Section 112 Eligibility To Be a New Source
    H. Other Testing and Monitoring Revisions
    I. Miscellaneous Amendments
    J. Standards During Periods of Startup and Shutdown

    K. Reporting for Malfunctions and Affirmative Defense for
Violation of Emission Standards During Malfunctions
    L. What are the compliance dates of the standards?
    M. Open Clinker Storage Piles
IV. Summary of Major Changes Since Proposal
    A. PM Parametric Monitoring
    B. Scaling for Continuous Parametric Monitoring of THC for
Alternative OHAP Standard
    C. Work Practice Standard in Lieu of Numerical Emissions Limits
for Periods of Startup and Shutdown
V. Summary of Significant Comments and Responses
    A. Amendments to Existing Source and New Source Standards for PM
Under CAA Sections 112(d) and 111(b)
    B. Mercury Standard
    C. Standards for Fugitive Emissions From Open Clinker Storage
Piles
    D. September 9, 2015, Compliance Date for the Amended Existing
Source Standards
    E. Eligibility to be a New Source Under NESHAP
VI. Summary of Cost, Environmental, Energy and Economic Impacts
    A. What are the affected sources?
    B. How did EPA evaluate the impacts of these amendments?
    C. What are the air quality impacts?
    D. What are the water quality impacts?
    E. What are the solid waste impacts?
    F. What are the secondary impacts?
    G. What are the energy impacts?
    H. What are the cost impacts?
    I. What are the health effects of these pollutants?
VII. 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
    K. Congressional Review Act

I. General Information

A. Executive Summary

    In this action the EPA is finalizing amendments to the NESHAP for
Portland cement plants and to the NSPS for Portland cement plants.
These amendments respond to petitions for reconsideration filed by the
Portland cement industry and to a decision by the United States Court
of Appeals for the District of Columbia Circuit (D.C. Circuit). The EPA
is retaining the stack emission standards for mercury, hydrogen
chloride (HCl), and total hydrocarbons (THC) under the NESHAP, amending
the stack emission standard for particulate matter (PM) under the
NESHAP, and making a conforming amendment to the NSPS for PM. The
amendments also include provisions which account for commingled HAP
emissions from coal mills that are an integral part of the kiln,
establish a continuous monitoring regime for parametric monitoring of
PM, set work practice standards for startup and shutdown, and revise
the compliance date for the PM, mercury, HCl, THC and clinker storage
pile existing source standards under the NESHAP. The EPA is also
retaining the affirmative defense for civil penalties for violations of
emission limits occurring as a result of a malfunction.
    These amendments are based on sound technical and legal
justifications, and result in cost savings and compliance flexibility
for the Portland cement industry. This result is consistent with
Executive Order 13563.
1. Purpose of the Regulatory Action
a. Need for the Regulatory Action
    The EPA is amending the NESHAP for the Portland cement source
category and the NSPS for Portland cement plants issued under sections
112(d) and 111(b) of the Clean Air Act (CAA). The most significant
amendment is to the NESHAP and NSPS for PM, to correct monitoring
issues with the PM compliance regime as promulgated in the 2010 final
rule. As a result of this amendment, the EPA is also setting a
compliance date of September 9, 2015, for meeting the PM, mercury, HCl
and THC existing source NESHAP.
    This final action also addresses the remand by the DC Circuit in
Portland Cement Ass'n v. EPA, 665 F. 3d 177 (DC Cir. 2011). In that
case, the court upheld all of the EPA's methodology for establishing
the Portland cement NESHAP, denied all petitions for review challenging
the NSPS, but also held that the EPA had arbitrarily denied
reconsideration of the NESHAP to take into account the effect of the
EPA's Nonhazardous Secondary Materials (NHSM) rule on the standards.
The NHSM rule, issued after the NESHAP was promulgated, had the effect
of reclassifying some cement kilns as commercial and industrial solid
waste incinerators (CISWI) and thus could have an effect on the
standards. The court also stayed the open storage clinker pile
standards.
    We are also amending various implementation requirements to provide
more compliance flexibility for affected sources. In addition, the
amendments address the issues on which the EPA previously granted
reconsideration. See 76 FR 28318 (May 17, 2011).
b. Legal Authority for the Regulatory Action
    These amendments implement sections 112(d) and 111(b) of the CAA.
Section 112 of the CAA establishes a regulatory process to address
emissions of hazardous air pollutants (HAP) from stationary sources.
After the EPA identifies categories of sources emitting one or more of
the HAP listed in section 112(b) of the CAA, section 112(d) requires
the EPA to promulgate technology-based NESHAP for those sources.
Section 112(i)(3)(A) requires that the compliance date for existing
sources shall be ``as expeditiou[s] as practicable,'' but not more than
3 years after a standard's effective date. Section 111 of the CAA
requires that NSPS reflect the application of the best system of
emission reductions achievable which, taking into consideration the
cost of achieving such emission reductions, and any non-air quality
health and environmental impact and energy requirements, the
Administrator determines has been adequately demonstrated.
2. Summary of Major Provisions
a. PM Emission Standards
    As proposed, the EPA is amending the existing and new source PM
standards in the NESHAP to require manual stack testing in lieu of PM
continuous emission monitoring systems (CEMS) for compliance
determinations and requiring that a site-specific parametric operating
level be established using a PM continuous parametric monitoring system
(CPMS). We are changing the numeric emissions value of those standards
for existing sources to 0.07 pounds per ton (lb/ton) clinker based on
manual stack testing and 0.02 lb/ton clinker for new and reconstructed
sources based on manual stack testing. The PM standards under the NSPS
for modified sources are likewise amended to 0.07 lb/ton clinker based
on manual stack testing and 0.02 lb/ton clinker for new and
reconstructed sources based on manual stack testing.
b. Response to Remand
    Consistent with the court's remand, the EPA has removed all of the
CISWI kilns from the database used to set the 2010 existing source
standards for PM,

mercury, HCl and THC. This analysis informed the level of the final
standards discussed immediately below.
c. Other Emissions Standards
    As proposed, the EPA is changing the alternative organic HAP (oHAP)
standard from 9 parts per million (ppm) to 12 ppm. The EPA is not
changing the existing or new source standards for mercury, THC or HCl.
d. Standards During Startup and Shutdown
    The EPA is amending the emission standards applicable during
periods of startup and shutdown from numerical standards to work
practice standards.
e. Compliance Dates for NESHAP
    As proposed, the EPA is establishing a compliance date of September
9, 2015, for existing source standards for PM, mercury, HCl and THC.
The EPA is establishing February 12, 2014, as the compliance date for
the standards for existing open clinker storage piles. New source
standards continue to apply to all sources which commenced construction
or reconstruction after May 6, 2009.
f. Final Action on Reconsideration
    The EPA is also taking final action on the remaining issues on
which it granted reconsideration on May 17, 2011.
3. Cost Impacts of These Amendments
    We estimate that revising the means of demonstrating compliance for
the PM, alternative organic HAP standards and requiring work practices
for open clinker storage piles will save industry $52 million annually.
4. Summary of Final Standards
    Table 1 shows the final standards for the Portland Cement
Manufacturing Industry NESHAP and the Portland Cement Plants NSPS.

               Table 1--Existing and New Source Standards
------------------------------------------------------------------------
                                    Existing source       New source
            Pollutant                  standard            standard
------------------------------------------------------------------------
Mercury.........................  55 lb/MM tons       21 lb/MM tons
                                   clinker.            clinker.
THC.............................  24 ppmvd..........  24 ppmvd.
PM..............................  0.07 lb/ton \a\     0.02 lb/ton \b\
                                   clinker (3-run      clinker (3-run
                                   test average).      test average).
HCl.............................  3 ppmvd...........  3 ppmvd.
Organic HAP (alternative to       12 ppmvd..........  12 ppmvd.
 Total Hydrocarbons).
------------------------------------------------------------------------
\a\ Also applies to NSPS modified sources.
\b\ Also applies to NSPS new and reconstructed sources.

B. Does this action apply to me?

    Categories and entities potentially regulated by this final rule
include:

 Table 2--Industrial Source Categories Affected by this NESHAP and NSPS
                              Final Action
------------------------------------------------------------------------
                                                  Examples of regulated
            Category             NAICS code \a\          entities
------------------------------------------------------------------------
Industry.......................          327310  Portland cement
                                                  manufacturing plants.
Federal government.............  ..............  Not affected.
State/local/tribal government..  ..............  Portland cement
                                                  manufacturing plants.
------------------------------------------------------------------------
\a\ North American Industry Classification System.

    Table 2 of this preamble 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 will be
regulated by this action, you should examine the applicability criteria
in 40 CFR 60.60 (subpart F) or in 40 CFR 63.1340 (subpart LLL). If you
have any questions regarding the applicability of this final action to
a particular entity, contact the appropriate person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.

C. Where can I get a copy of this document?

    In addition to being available in the docket, an electronic copy of
this final action will also be available on the World Wide Web (WWW)
through the EPA's Technology Transfer Network (TTN). Following
signature by the EPA Administrator, a copy of this final action will be
posted on the TTN's policy and guidance page for newly proposed or
promulgated rules at the following address: http://www.epa.gov/ttn/oarpg. The TTN provides information and technology exchange in various
areas of air pollution control. In addition, more information can be
obtained at the following address: http://www.epa.gov/airquality/cement.

D. Judicial Review

    Under section 307(b)(1) of the CAA, judicial review of this final
action is available only by filing a petition for review in the court
by April 13, 2013. Under section 307(b)(2) of the CAA, the requirements
established by the final rule may not be challenged separately in any
civil or criminal proceedings brought by the EPA to enforce the
requirements.
    Section 307(d)(7)(B) of the CAA further provides that ``[o]nly an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review.'' This section also
provides a mechanism for the EPA to convene a proceeding for
reconsideration, ``[i]f the person raising an objection can demonstrate
to EPA that it was impracticable to raise such objection within [the
period for public comment] or if the grounds for such objection arose
after the period for public comment (but within the time specified for
judicial review) and if such objection is of central relevance to the
outcome of the rule.'' Any person seeking to make such a demonstration
to us should submit a Petition for Reconsideration to the Office of the
Administrator, U.S. EPA, Room 3000,

Ariel Rios Building, 1200 Pennsylvania Ave. NW., Washington, DC 20460,
with a copy to both the person(s) listed in the preceding FOR FURTHER
INFORMATION CONTACT section and the Associate General Counsel for the
Air and Radiation Law Office, Office of General Counsel (Mail Code
2344A), U.S. EPA, 1200 Pennsylvania Ave. NW., Washington, DC 20460.

II. Background Information

A. What is the statutory authority for these amendments?

    Section 112 of the CAA establishes a regulatory process to address
emissions of HAP from stationary sources. After the EPA has identified
categories of sources emitting one or more of the HAP listed in section
112(b) of the CAA, section 112(d) requires us to promulgate NESHAP for
those sources. For ``major sources'' that emit or have the potential to
emit 10 tons per year (tpy) or more of a single HAP or 25 tpy or more
of a combination of HAP, these technology-based standards must reflect
the maximum reductions of HAP achievable (after considering cost,
energy requirements and non-air quality health and environmental
impacts) and are commonly referred to as maximum achievable control
technology (MACT) standards.
    The statute specifies certain minimum stringency requirements for
MACT standards, which are referred to as ``floor'' requirements. See
CAA section 112(d)(3). Specifically, for new sources, the MACT floor
cannot be less stringent than the emission control that is achieved in
practice by the best controlled similar source. The MACT standards for
existing sources can be less stringent than standards for new sources,
but they cannot be less stringent than the average emission limitation
achieved by the best-performing 12 percent of existing sources (for
which the Administrator has emissions information) in the category or
subcategory (or the best-performing five sources for categories or
subcategories with fewer than 30 sources).
    In developing MACT, we must also consider control options that are
more stringent than the floor. We may establish standards more
stringent than the floor based on the consideration of the cost of
achieving the emissions reductions, any non-air quality health and
environmental impacts, and energy requirements. See CAA section
112(d)(2).
    Under section 112(i)(3)(A), compliance dates for existing sources
shall ``be as expeditiou[s] as practicable'', but in no event later
than 3 years after the date of publication of the final rule in the
Federal Register. The EPA may set a revised compliance date of a MACT
standard when amending that standard, see NRDC v. EPA, 489 F. 3d 1364,
1373-74 (D.C. Cir. 2007), but any such amended compliance date must
still establish ``compliance as expeditiously as practicable.''
    Section 111(b) requires the EPA to set standards for emissions that
``reflect the degree of emission limitation achievable through the
application of the best system of emission reduction.'' See CAA section
111(a)(1). In contrast to the NESHAP floor setting process, NSPS
requires the EPA to take into account the ``cost of achieving''
emissions reductions, as well as health, environmental, and energy
considerations. Id.

B. What actions preceded this final rule?

    The history of this final rule, commencing with the 1999 standards
and proceeding through the amendments issued in September 2009, is set
out in detail in 75 FR 54970 (Sept 9, 2010). The Portland Cement
Association (PCA) and several cement companies filed petitions for
reconsideration of aspects of those amendments (copies of the petitions
are in the Portland Cement Reconsideration docket, EPA-HQ-OAR-2011-
0817). On May 17, 2011, the EPA granted reconsideration of various
issues, and denied the petitions to reconsider as to the remaining
issues. See 76 FR 28318 (May 17, 2011). On December 9, 2011, the D.C.
Circuit issued an opinion upholding the NESHAP itself (as well as the
section 111 NSPS), but finding that the EPA had arbitrarily failed to
grant reconsideration to consider the effect of the EPA's NHSM rule on
the standards (76 FR 15456 (March 21, 2011)), The NHSM rule had the
effect of reclassifying some cement kilns as commercial and solid waste
incinerators. See Portland Cement Ass'n v. EPA, 665 F. 3d 177, 186-189
(D.C. Cir. 2011). The court did not stay any of the numerical emission
standards, but did stay the work practice standards for open clinker
storage piles pending the conclusion of the reconsideration process.
See 665 F. 3d at 194.
    In this action, the EPA is responding to the court's remand. For
existing sources, the EPA had done so by removing all kilns classified
as CISWI units from the data used to establish the 2010 NESHAP
standards. The EPA then recalculated each of the floors based on this
dataset (the 2010 dataset minus CISWI units) and made beyond-the-floor
determinations based on the recalculated floors. The EPA believes that
this approach is properly responsive to the court's remand. See 665 F.
3d at 188 where the court referred favorably to this type of
recalculation. For new sources, EPA used the same data as used to
establish the 2010 floors--namely the performance of the best
controlled similar sources as required by section 112(d)(3).

III. Summary of Final Amendments to Subpart LLL and Subpart F

    As discussed in the preamble of the proposed rule, 77 FR 42368, in
this final action the EPA is finalizing several amendments to Subpart
LLL and Subpart F. These amendments are summarized below.

A. Reconsideration of Standards

    As noted above, EPA has responded to the action of the DC Circuit
by removing all CISWI cement kilns from the database used to establish
the existing source standards, and recalculating existing source floors
and standards from that revised database. As described in the preamble
of the proposal, the EPA had determined based on the final NHSM rule
that there are 24 cement kilns which combust solid waste. 77 FR 42372.
During the comment period, one company provided reliable information in
its comments regarding the materials it processes indicating that one
of these kilns is, in fact, a cement kiln (meaning that the EPA had
properly classified it as a cement kiln in the 2010 rulemaking).\1\
After reviewing the information provided, the EPA agrees that this
source should not be classified as a CISWI kiln and, therefore, should
not be removed from the Portland cement kiln database. We received no
other comments concerning the identification of cement kilns and CISWI
units. There are thus now 23 kilns identified as combusting solid waste
and therefore classified as CISWI units. As directed by the Court's
decision, we removed these 23 kilns from the database and recalculated
the floors. This calculation resulted in the same floors as proposed in
the July 2012 proposal.
---------------------------------------------------------------------------

    \1\ The company burns dried biosolids as a fuel which are not
classified as solid wastes. Refer to the Docket, No. EPA-HQ-OAR-
2011-0817-0482.
---------------------------------------------------------------------------

    Consistent with this analysis, the EPA is finalizing amendments to
the emission standards as follows:

1. PM Emission Standards
    The EPA is revising several provisions of the emission standards
for PM as follows:
     Changing the compliance basis for the PM standards from
continuous monitoring with a PM CEMS to a manual three run stack test,
amending the level and averaging time of the standard, and requiring a
continuous parametric monitoring system using a CPMS. As a consequence,
the EPA is also:
     Amending PM standards under the NESHAP for existing
sources to 0.07 lb/ton clinker based on manual stack testing, and 0.02
lb/ton clinker for new and reconstructed sources based on manual stack
testing;
     Amending PM standards under the NSPS for modified sources
to 0.07 lb/ton clinker based on manual stack testing and 0.02 lb/ton
clinker for new and reconstructed sources likewise based on manual
stack testing;
     Requiring that sources establish a site-specific
parametric operating limit for PM, and requiring that the parametric
limit be continuously monitored using a PM CPMS;
     Requiring that sources retest once a year to reset the PM
CPMS operating limit;
     Adding a provision that, if a source exceeds that site-
specific parametric operating limit, it must conduct corrective action
including performing a Method 5 or 5I performance test within 45 days;
in addition, if the source exceeds that parametric limit four times in
a calendar year, the source is presumed to be in violation of the PM
emissions standard itself, subject to rebuttal by the source.
2. Mercury Standard
    As proposed, the EPA is establishing a standard for mercury of 55
pounds per million (lb/MM) tons clinker for existing sources and is not
changing the emission standard (21 lb/MM tons clinker) for new sources.
The emission standard for existing sources is the same as the 2010
standard but is a beyond the floor standard.
3. Other Emissions Standards
    As the Court requested, the EPA removed the CISWI units from the
database and re-calculated the standards for THC and HCl. The standards
remain the same as they were in the final 2010 rule. See also 76 FR
21149, 21152, and 21154 explaining why beyond the floor standards for
THC and HCl are not justified. The 2010 rules provide an alternative to
the THC standard whereby sources can meet a limit for non-dioxin
organic HAP by measuring those HAP directly rather than meeting the
standard for THC (a surrogate for non-dioxin organic HAP). As proposed,
the EPA is changing the level of the alternative non-dioxin organic HAP
standard from 9 ppm to 12 ppm. Table 3 summarizes the Final Existing
and New Source Standards

             Table 3--Existing and New Source Standards \a\
------------------------------------------------------------------------
                                    Existing source       New source
            Pollutant                  standard            standard
------------------------------------------------------------------------
Mercury.........................  55 lb/MM tons       21 lb/MM tons
                                   clinker.            clinker.
THC.............................  24 ppmvd..........  24 ppmvd.
PM..............................  0.07 lb/ton         0.02 lb/ton
                                   clinker (3-run      clinker (3-run
                                   test average).      test average).
HCl.............................  3 ppmvd...........  3 ppmvd.
Organic HAP \b\.................  12 ppmvd..........  12 ppmvd.
------------------------------------------------------------------------
\a\ Standards for mercury and THC are based on a 30-day rolling average.
  The standard for PM is based on a three-run test. If using a CEMS to
  determine compliance with the HCl standard, the floor is also a 30-day
  rolling average.
\b\ If the source opts to comply with the THC emission limit, this
  standard does not apply.

B. Continuously Monitored Parameters for Alternative Organic HAP
Standard (With THC Monitoring Parameter)

    In addition to amending the level of the alternative oHAP standard
(i.e., the standard whereby sources meet a standard for oHAP rather
than for THC), the EPA is amending the provisions for the site-specific
THC operating parameter for that alternative standard (where THC is a
site-specific parameter monitored continuously to show compliance with
the oHAP standard). The THC operating parameter is established based on
THC levels measured during the successful stack test where oHAP are
measured directly to demonstrate compliance. As amended, if compliance
source testing of oHAP averages a value that is 75 percent or less of
the emission limit for oHAP, the facility is allowed to establish a THC
parametric operating level corresponding to 75 percent of the oHAP
emission limit. We are adopting this provision to avoid penalizing
lower-emitting sources by burdening them with the most stringent
parametric operating levels. The EPA is adopting a similar provision
for continuous PM parametric monitoring, for the same reason (see
Section IV.A below). Sources which show oHAP emissions in compliance,
but greater than 75 percent of the standard, must establish the average
THC concentration measured during the 3-hour organic HAP test and use
that as the site-specific THC operating level. Thus, the parametric
monitoring level for THC will be the level corresponding to oHAP levels
of 75 percent of the standard or the THC level of the oHAP performance
test, whichever is higher.\2\ Compliance with the oHAP standard will be
shown as a ratio of three test runs during mill-on conditions and three
test runs during mill-off conditions, with the percentage of operating
time spent in each condition determining the ratio. The parametric
operating level will be set according to average THC values measured
during these same test runs, or to the default value of 75 percent of
the standard, as just explained. In addition, the EPA will allow
facilities to extend the testing time of the oHAP performance test if
they believe extended testing is required to adequately capture THC
variability over time. This final rule further requires that the stack
test for oHAP be repeated every 30 months to establish a new site-
specific THC parameter.
---------------------------------------------------------------------------

    \2\ If a source believes that monitoring non-methane THC rather
than total THC is a more reliable indicator of its oHAP emissions,
it can submit an alternative monitoring request pursuant to the
requirements of 40 CFR 63.8(f).
---------------------------------------------------------------------------

C. Allowing Sources With Dry Caustic Scrubbers To Comply With HCl
Standard Using Performance Tests

    The 2010 rule allows sources equipped with wet scrubbers to comply
with the HCl standard by means of periodic performance tests rather
than with continuous monitoring of HCl with a CEMS. Sources electing to
comply by means of stack tests must establish continuously monitored
parameters including liquid flow rate, pressure, and pH. Under this
final rule, kilns with dry scrubbers may also demonstrate

compliance with the HCl emissions limit by means of an initial and
periodic stack test rather than with continuous compliance monitoring
with an HCl CEMS. If a kiln equipped with a dry scrubber chooses this
alternative, this final rule requires that the sorbent injection rate
used during a successful performance test be recorded and then
continuously monitored to show that the injection rate remains at or
above the rate used during the performance test.
    Where either wet or dry scrubbers are used, owners and operators
may also establish sulfur dioxide (SO2) as an operating
parameter, rather than, for example, sorbent injection rate, liquid
injection rate or pressure drop. If the owner or operator of a
scrubber-equipped kiln makes this choice, it must establish the
SO2 operating limit equal to the average of the HCl levels
recorded during the HCl performance test, and meet that operating limit
on a 30 day rolling average basis. If a source exceeds any established
parameter level, it must retest for HCl in order to verify compliance
with the HCl emissions standard and must verify or re-establish the
parametric monitoring levels as well.
    At a minimum, a repeat performance test to confirm compliance with
the HCl emissions limit is required every 30 months.

D. Alternative PM Limit

    The 2010 final rule established an alternative PM limit to
accommodate situations where kilns combine exhaust gas from various
operations. 77 FR 42382. The equation establishing the alternative
limit contained certain technical errors which the EPA proposed to
correct. As proposed, this final rule revises the alternative PM
equation so that it includes exhaust gas flows from all sources that
would potentially be combined, including exhausts from the kiln, the
alkali bypass, the coal mill, and the clinker cooler, for an existing
kiln. The EPA is thus finalizing the following equation:

PMalt = 0.0060 x 1.65 x (Qk + Qc +
Qab + Qcm)/(7000)

Where:

PMalt = The alternative PM emission limit for commingled
sources.
0.0060 = The PM exhaust concentration (grains per dry standard cubic
feet (gr/dscf)) equivalent to 0.07 lb per ton clinker where clinker
cooler and kiln exhaust gas are not combined.
1.65 = The conversion factor of lb feed per lb clinker.
Qk = The exhaust flow of the kiln (dscf/ton feed).
Qc = The exhaust flow of the clinker cooler (dscf/ton
feed).
Qab = The exhaust flow of the alkali bypass (dscf/ton
feed).
Qcm = The exhaust flow of the coal mill (dscf/ton feed).
7000 = The conversion factor for grains (gr) per lb.

    If exhaust gases for any of the sources contained in the equation
are not commingled and are exhausted through a separate stack, their
value in the equation would be zero. The alternative PM equation for
new sources is identical to the existing source equation except the PM
exhaust concentration used in the equation is 0.002 gr/dscf, which is
equivalent to the new source PM limit of 0.02 lb/ton clinker.

E. Coal Mills

    The EPA discussed at length in the preamble to the proposed rule a
potential regulatory regime to cover situations where a portion of the
kiln exhaust is ducted to the coal mill. See 77 FR 42383-85; see also
the regulatory text at 77 FR 42398, 42402-06, 42408-09. To assure that
cement kilns do not exhaust untreated HAP through coal mills, and to
assure accurate accounting of commingled emissions so that cement kilns
are not penalized for commingling emissions where it makes sense to do
so, the EPA is finalizing rules applicable to kiln/coal mill emissions
for two configurations. In one, a portion of the kiln exhaust is ducted
to a coal mill, and then the coal mill exhaust is commingled with
remaining kiln exhaust and discharged through the main kiln stack. In
the other, a portion of the kiln exhaust is routed through the coal
mill and discharged through the coal mill stack.
    In the case of a coal mill that receives and discharges a portion
of the cement kiln exhaust, this final rule requires that the sum of
the mercury, THC and HCl in the kiln exhaust diverted to the coal mill,
and the kiln exhaust exhausted from the main kiln stack, must not
exceed the subpart LLL emission limits for each respective HAP or HAP
surrogate. The facility must document the contribution of the emissions
diverted to the coal mill. For mercury, the rule allows tests to be
performed downstream of the coal mill to take advantage of any mercury
removal that occurs in the coal mill air pollution control device, and
to avoid double counting emissions from mercury that becomes re-
entrained in the coal. For THC and HCl, the rule allows tests to be
performed upstream of the coal mill to avoid any THC or HCl that might
be emitted by the coal. For owners and operators who believe that the
impact of the testing location (upstream or downstream of the coal
mill) would not result in their exceeding the kiln mercury, THC or HCl
emissions limits and wish to conduct all their THC, HCl and mercury
testing at a single location, this final rule allows testing either
upstream or downstream of the coal mill. For sources complying with the
alternate organic HAP limit, the facility would not be required to test
for THC emissions, but would test for the organic HAP and add that
concentration to the remaining emission points to estimate their total
emissions for organic HAP.
    A cement kiln that commingles emissions from its coal mill with all
other kiln exhaust emissions and discharges through a single stack
could simply meet the kiln emission limits. In the case of PM, the
additional flow from the coal mill would be accounted for in the
equation used to determine PM contributions from commingled flows. See
section D above. In this configuration, the source would also have the
option of monitoring and/or testing kiln exhaust gases prior to the
introduction of the coal mill exhaust gas, and testing the kiln gas
diverted to the coal mill. In this case this final rule requires that
the sum of the mercury, THC (or organic HAP if the source chooses the
alternative organic HAP limit), and HCl in the kiln exhaust diverted to
the coal mill plus the kiln exhaust measured in the main kiln exhaust
must not exceed the subpart LLL emission limits for each respective HAP
or HAP surrogate.
    The same provisions for coal mills also apply to kilns equipped
with an alkali bypass. The one minor exception is that for PM, the
summed PM emissions from the kiln and alkali bypass must be equal to or
less than the PM limit in subpart LLL. Tests for PM from the alkali
bypass must be conducted downstream of the alkali bypass air pollution
control devices (APCD) to account for those emission reductions.
    With regard to PM, the EPA stated at proposal that where a coal
mill receives and discharges a portion of the cement kiln exhaust, the
kiln owner operator would have to demonstrate compliance with the 40
CFR 60 subpart Y standard for PM. Although the subpart Y standard is
numerically higher than the subpart LLL PM standard, EPA assumed that
control would be to the same level because the subpart Y PM standard is
predicated on use of fabric filer control technology. 77 FR 42383/2.
However, a commenter pointed out accurately that this proposal
contravened the basic principle EPA indicated it was adopting here of
not allowing diverted kiln emissions to meet a more lenient standard
than required by the NESHAP,

and further indicated that EPA had failed to show that these diverted
PM emissions were controlled as required by section 112(d)(2) and (3)
of the Act. EPA agrees with this comment, and accordingly is indicating
in the final rule that commingled emissions in this situation would be
required to meet the subpart LLL NESHAP for PM. Because coal mill
stacks are controlled with fabric filters, we project that they can
meet the subpart LLL numeric standard without further controls. See 77
FR 42383. Coal mill stacks will be required to meet annual PM
performance testing and combine the measured emissions with PM
emissions from the separated alkali stack, bypass stack, and/or main
kiln as required in sections 60.62(b)(3), 63.1349 and 63.1350 of this
rule.
    This final rule also states that sources equipped with an alkali
bypass stack or sources that exhaust kiln gases to a coal mill that
exhausts through a separate stack are not required to install CEMS on
these stacks. Instead of installing a CEMS, such sources may use the
results of the initial and subsequent performance test to demonstrate
compliance with the PM, THC, HCl and mercury emissions limits. Note
that for the main kiln exhaust, the CEMS requirements remain.
    We expand on these monitoring provisions below.
1. Mercury
    Although mercury from the kiln stack is monitored using a CEMS,
mercury emissions from the coal mill are based on a periodic
performance test and use of the gas flow rate to the coal mill.
Performance tests for mercury must be conducted annually unless and
until the tested mercury levels are below the method detection limits
for two consecutive years, after which tests may be conducted every 30
months. The performance test results must be summed with the emissions
from the kiln stack to determine compliance. The coal mill exhaust
mercury emissions are calculated on a mass basis using the measured
mercury concentration and the coal mill exhaust gas flow. The coal mill
exhaust flow is established using a continuous monitoring system (CMS),
or the design maximum flow rate. Mass mercury emissions from the coal
mill would be summed with the hourly mercury emissions from the kiln
measured by the mercury CEMS. Hourly mercury emissions are then summed
to calculate the rolling 30-day mass mercury emissions. This number is
then divided by the corresponding 30 days of clinker production to
determine the 30-day rolling average. This final rule provides
equations for summing emissions from the coal mill with the mercury
emissions from the kiln to determine continuous compliance. To see an
example calculation, see Section 4 of the Portland Cement
Reconsideration Technical Support Document (developed for the
proposal), docket item EPA-HQ-OAR-2011-0817-0225.
2. THC and HCl
    In this case, site specific kiln stack emission limits (to be
continuously monitored) are to be calculated taking into consideration
the volumetric exhaust gas flow rates and concentrations of all
applicable effluent streams (kiln stack, coal mill and alkali bypass)
for the kiln unit. In order to determine the flow rates and
concentrations of THC and HCl in the coal mill and alkali bypass
streams, the source must test every 30 months using the appropriate
test method. For HCl, the performance test must be performed using
Method 321 in Appendix A to 40 CFR Part 63. For measurement of THC,
Method 25A in Appendix A-7 to 40 CFR Part 60 is required. With these
data, the concentration of THC and HCl that must be monitored by the
kiln CEMS in order to demonstrate compliance with the kiln MACT limit
can be calculated using the equations in this final rule. As with
mercury, the coal mill flow rate used to calculate the allowable main
kiln stack THC and HCl concentrations can be based on a CMS, or on the
maximum design flow rate. The sum of the kiln CEMS and the maximum
emissions from the coal mill or alkali bypass must be at or below the
subpart LLL limits for THC and HCl. See Section 4 of Portland Cement
Reconsideration Technical Support Document (developed for the
proposal), docket item EPA-HQ-OAR-2011-0817-0225, for an example
calculation.
    Also, as a result of these revisions, the EPA is revising the
definition of kiln to include inline coal mills and adding a definition
of inline coal mill.

F. NESHAP Compliance Date Extension for Existing Sources

    This final rule establishes that the compliance date for the
amended PM standard, and for the THC, mercury and HCl standards, for
existing sources for kilns, clinker coolers and raw material dryers is
September 9, 2015. This final rule also establishes February 12, 2014,
as the compliance date for the existing open clinker storage pile work
practice standards. A detailed discussion of these compliance dates can
be found in Section V.D. below.

G. Section 112 Eligibility To Be a New Source

    The EPA is not changing the date for new source eligibility under
the NESHAP. Thus, a source that commenced construction or
reconstruction after May 6, 2009, would remain subject to the section
112 new source standards. A more detailed discussion of this topic can
be found below in Section V.E.

H. Other Testing and Monitoring Revisions

    In this action we are finalizing the proposed corrections and
clarifications to the 2010 rule including changes to: Equations for
calculating rolling operating day emissions rates; procedures that
include extraneous wording; and cross references and typographical
errors in the rule.\3\
---------------------------------------------------------------------------

    \3\ We note that these changes required the agency to reprint
sections of regulatory text. See e.g. 63.1348(a)(3)(i). In
reprinting these passages, EPA has not reopened, reconsidered, or
otherwise reevaluated the substance of these provisions but rather
is only making the needed technical alteration.
---------------------------------------------------------------------------

    For sources that are required to monitor HCl emissions with a CEMS,
we are revising the requirements for using HCl CEMS to define the span
value for this source category, to include quality assurance measures
for data collected under ``mill off'' conditions, and to clarify use of
performance specification (PS) 15. This final rule also removes from
the standard the oxygen correction factors for raw material dryers and
makes minor, non-substantive changes to the sections and paragraphs
below:
     Section 60.62(d).
     Section 60.63(b)(1)(i) and (ii), (b)(2), (f)(1), (2), (4),
(5), (h)(1) and (6) through (9) (i).
     Section 60.64(b)(2).
     Section 60.66.
     Section 63.1340(b)(1) and (6) through (8).
     Section 63.1346(a) and (c) through (e).
     Section 63.1348(a)(2), (3)(i) through (iii), (a)(4)(i)(A),
(a)(4)(ii) and (iv).
     Section 63.1348(b)(1)(i), (iii) and (iv).
     Section 63.1348(b)(3), (5), (6)(i), (8) and (c)(2)(iv).
     Section 63.1349(a), (b)(3), (d)(1) and (d)(2) and (e).
     Section 63.1350(d)(1)(i) and (ii), (f), (f)(2)(i) and
(iii), (f)(3), (f)(4), (g)(1) and (2), (k), l(2), (m)(3), (m)(10) and
(11), (o) and (p).
     Section 63.1352(b).
     Section 63.1356.
     In addition, we are adding requirements in section
63.1348(a), that

a cement kiln that becomes subject to the rule after having been
subject to the CISWI regulations, must meet all the initial compliance
testing requirements even if they were previously subject to Subpart
LLL.

I. Miscellaneous Amendments

    We are also finalizing amendments to clarify various requirements
in this final rule including issues of applicability, treatment of
multiple sources that vent to a single stack, third party
certification, definitions and use of bag leak detection systems when
PM CPMS are in use.
    For raw material, clinker or finished product storage bins, we have
clarified that the requirements of this final rule apply only at
facilities that are a major source (see section 63.1340(b)(6)) and that
affected sources that are subject to subpart OOO (standards for
nonmetallic mineral processing) are not subject to the requirements of
subpart LLL (see section 63.1340(c)).
    With regard to the NSPS, to clarify the recordkeeping and reporting
requirement in section 60.65(a) to submit excess emission reports, we
have added to section 60.61 of the NSPS a definition of ``excess
emissions'' to mean ``with respect to this subpart, results of any
required measurements outside the applicable range (e.g., emissions
limitations, parametric operating limits) that is permitted by this
subpart. The values of measurements will be in the same units and
averaging time as the values specified in this subpart for the
limitations.'' To clarify what data are used in the calculation of
emissions, or used in the calculation of parametric levels that are
used to demonstrate continuous compliance, we added to this section a
definition of ``operating day'' to mean ``a 24-hour period beginning at
12:00 midnight during which the kiln operates at any time. For
calculating rolling 30-day average emissions, an operating day does not
include the hours of operation during startup or shutdown.'' The
definition for ``operating day'' in section 63.1341 of the NESHAP is
revised to be consistent with the above definition. We also became
aware that some raw material dryers may be used to dry materials other
than kiln feed and we have revised the definition of ``raw material
dryer'' in recognition of that fact.

J. Standards During Periods of Startup and Shutdown

    In the 2010 final NESHAP, the EPA established separate standards
for periods of startup and shutdown which differ from the main
standards that apply during steady state operations. In this action,
based on comments received and the EPA's reconsideration of several
technical issues related to startup and shutdown, the EPA is adopting
work practices in place of these numerical standards. The rationale and
provisions for the work practice standards are discussed in detail in
section IV.C.
    The EPA is also clarifying the operating conditions during which
these standards apply, including a definition of ``startup'' and
``shutdown''. Under the amended definition, startup begins when the
kiln's induced fan is turned on and fuel combustion is occurring in the
main burner of the kiln. Startup ends when feed has been continuously
fed to the kiln for at least 120 minutes or when the kiln feed rate
exceeds 60 percent of the kiln design limitation rate. Shutdown begins
when continuous feed to the kiln is halted and ends when continuous
kiln rotation ceases.
    The startup and shutdown-related changes include:
     Adding a definition of startup and shutdown in section
63.1341, as described;
     Adding section 63.1346(f) describing work practice
standards to be met during periods of startup and shutdown;
     Revising section 63.1347 to require that startup and
shutdown procedures be included in the facility's operation and
maintenance plan;
     Adding section 63.1355(f) requiring records of each
startup and shutdown including the date, time and duration and the
quantity of feed and fuel added to the kiln during startup and
shutdown;
     Adding section 63.1348(b)(9) requiring continuous
compliance by operating all air pollution control devices during
periods of startup and shutdown.

K. Reporting for Malfunctions and Affirmative Defense for Violation of
Emission Standards During Malfunctions

    The EPA added to the September 9, 2010, final NESHAP rule an
affirmative defense to civil penalties for violations of emissions
limits that are caused by malfunctions. Various environmental advocacy
groups, as well as the PCA, indicated that there had been insufficient
notice of this provision. The EPA agreed and granted reconsideration.
See 76 FR 28325 (May 17, 2011). This action finalizes the EPA's
decision to retain the affirmative defense on reconsideration.
    The EPA is retaining in the final NESHAP rule an affirmative
defense to civil penalties for violations of emission standards that
are caused by malfunctions. See 40 CFR 63.1341 (defining ``affirmative
defense'' to mean, in the context of an enforcement proceeding, a
response or defense put forward by a defendant, regarding which the
defendant has the burden of proof, and the merits of which are
independently and objectively evaluated in a judicial or administrative
proceeding). We are also revising some of the regulatory provisions
that specify the elements that are necessary to establish this
affirmative defense as proposed with minor changes from proposal
described later in this section. The source must prove by a
preponderance of the evidence that it has met all of the elements set
forth in section 63.1344. (See 40 CFR 22.24). The criteria are designed
in part to ensure that the affirmative defense is available only where
the event that causes a violation of the emission standard meets the
narrow definition of malfunction in 40 CFR 63.2 (sudden, infrequent,
not reasonably preventable and not caused by poor maintenance or
careless operation). For example, to successfully assert the
affirmative defense, the source must prove by a preponderance of the
evidence that the violation ``[w]as caused by a sudden, infrequent, and
unavoidable failure of air pollution control, process equipment, or a
process to operate in a normal or usual manner * * *.'' The criteria
also are designed to ensure that steps are taken to correct the
malfunction, to minimize emissions in accordance with section 63.1344
and to prevent future malfunctions.
    Similar to actions taken in several other recent NESHAP amendments
(see National Emissions Standards for Hazardous Air Pollutants From
Secondary Lead Smelting, 77 FR 556, January 5, 2012, National Emission
Standards for Hazardous Air Pollutant Emissions for Shipbuilding and
Ship Repair (Surface Coating), and National Emission Standards for Wood
Furniture Manufacturing Operations, 76 FR 72050, November 21, 2011),
the EPA included an affirmative defense in the 2010 final rule and is
retaining it in this rule (see section 63.1344). The affirmative
defense provisions give the EPA the flexibility to both ensure that its
emission standards are ``continuous'' as required by 42 U.S.C. Sec.
7602(k), and account for unplanned upsets and thus support the
reasonableness of the standard as a whole. In addition to the authority
cited in support of the affirmative defense in the preamble to the
proposed rule, the EPA notes that a recent court decision further
supports

the EPA's authority to promulgate an affirmative defense. The United
States Court of Appeals for the Fifth Circuit recently upheld the EPA's
view that an affirmative defense provision is consistent with section
113(e) of the Clean Air Act. Luminant Generation Co. LLC v. United
States EPA, 2012 U.S. App. LEXIS 21223 (5th Cir. Oct. 12, 2012)
(upholding the EPA's approval of affirmative defense provisions in a
CAA State Implementation Plan). As discussed in the preamble to the
proposed rule (77 FR 42379), the EPA's view is that an affirmative
defense to civil penalties for exceedances of applicable emission
standards during periods of malfunction appropriately resolves an
underlying tension inherent in many types of air regulation, to ensure
continuous compliance while simultaneously recognizing that despite the
most diligent of efforts, emission limits may be exceeded under
circumstances beyond the control of the source. See generally, Virginia
v. Browner, 80 F.3d 869, 878 (4th Cir. 1996) (the EPA's interpretation
that resolved a tension within the CAA is reasonable). The EPA has used
its section 301(a)(1) authority to issue regulations necessary to carry
out the Act in a manner that appropriately balances these competing
concerns.
    We are promulgating revisions to the affirmative defense provisions
in section 40 CFR 63.1344 as described at proposal (77 FR 42380) and
making some minor additional revisions. The phrase ``emission limit''
was changed to ``emission standards'' to reflect that the affirmative
defense could be applicable to certain work practice standards. The
phrase, ``Off-shift and overtime labor were used, to the extent
practicable to make these repairs'' was removed. The term
``notification'' to ``reporting'' was changed to reflect that the root
cause analysis required under affirmative defense would be submitted
with other periodic reporting. The term ``and monitoring'' was deleted
because monitoring malfunctions are defined differently than
malfunctions of process and control units and the affirmative defense
is intended to apply to malfunctions to affected units that cause a
failure to meet an emission standard. The word ``however'' was removed
to incorporate more plain language into the regulation. The phrase
``the respondent fails'' was removed and replaced with ``you fail'' to
incorporate more plain language into the regulation. The word ``its''
was replaced with ``your'' to incorporate more plain language into the
regulation. The phrase ``all of the'' was replaced with ``your'' also
to incorporate more plain language into the regulation. The phrase
``air pollution control practice'' was shortened to ``good practices''
to incorporate more plain language into the regulation. In addition,
the written report required when asserting an affirmative defense was
changed from a separate ``semiannual'' report to a report that is
submitted with the first periodic compliance, deviation report or
excess emission report due after the event.
    We are finalizing the reporting and recordkeeping associated with
violations due to malfunctions as described at proposal (77 FR 42388)
and making some minor additional revisions as described below.
     Revising section 63.1354(b)(vii) for reporting and
recordkeeping violations due to malfunctions. The phrase ``failure to
meet a standard'' was used to replace ``deviation'' in the requirement
to report violations of the standard. This was changed because the EPA
is not finalizing a definition of deviation in this subpart and the
term is not defined in the general provisions.
     Revising section 63.1354(c) for reporting a failure to
meet a standard due to a malfunction. In addition, the phrase ``failure
to meet a standard'' was used to replace ``deviation'' in the
requirement to report violations of the standard. This was changed
because the EPA is not finalizing a definition of deviation in this
subpart and the term is not defined in the general provisions.
     Revising section 63.1355(f) addressing recordkeeping
during startup and shutdown. The proposed recordkeeping requirement
applicable to startup and shutdown assumed that a numerical emission
standard was applicable during startup and shutdown. In finalizing the
work practice standards in 63.1346(f) there will no longer be a
numerical emission standard applicable during startup and shutdown. As
such the recordkeeping requirement must change to reflect the content
of the work practice standard. Records must be kept of the date, time
and duration of the periods when the work practice is applicable, as
well as the fuel and feed data to demonstrate compliance with the work
practice standard.

L. What are the compliance dates of the standards?

    During the comment period, comments were received that confirmed
the need for additional compliance time, since the revised standards
can result in different compliance strategies relative to the 2010
final rule. Thus, as proposed, this final rule establishes the
compliance date for the amended existing source standards including
standards for PM, mercury, HCl and THC to be September 9, 2015. The
existing source compliance date for the requirements for open clinker
storage piles is February 12, 2014. New sources which commenced
construction or reconstruction after May 6, 2009, would remain subject
to the new source standards and a compliance date of February 12, 2013,
or startup, whichever is later.

M. Open Clinker Storage Piles

    The EPA has added work practice requirements for open clinker
storage piles that will reduce fugitive dust emissions from these
sources. This final rule also contains a definition of open clinker
storage piles and requires that a source's operation and maintenance
plan include the steps the facility will take to minimize fugitive dust
emissions from open clinker storage piles. A detailed discussion of
these requirements can be found in section V.C below.

IV. Summary of Major Changes Since Proposal

A. PM Parametric Monitoring

    Changes to PM Parametric Monitoring. The EPA proposed the use of PM
CPMS for continuous monitoring of PM emissions as a 30-day rolling
average established by identifying the average PM CPMS response
corresponding to the highest 1-hour PM compliance test. Failure to meet
this 30-day rolling average would result in retesting, and more than
four exceedances from the parametric limit in a year would be presumed
(subject to possibility of rebuttal by the source) to be a violation of
the emission standard itself. See 77 FR 42377. Industry commented that
this requirement would trigger unnecessary retests for many facilities,
especially for the lower-emitting sources. The issue of increased
compliance burden falling on the lower emitting sources is legitimate.
Sources with especially low PM limits in their performance test would
be most at risk of exceeding a parametric limit due to a few emission
spikes, even though they would still be operating well under the actual
PM compliance limit. We also received comment that the highest PM
performance test run may represent, in some circumstances, a number
higher than the PM emissions standard. To avoid this eventuality we
have changed the final rule to require setting the PM operating limit
equivalent to the average of the three PM performance tests, which
constitutes the demonstration of compliance with the standard. To avoid

penalizing lower emitting facilities, the EPA has modified the way PM
CPMS operating limits are established. Sources whose compliance with
the PM emission standard are shown to be 75 percent or below the
emission limit in the PM method 5 compliance test will set their PM
parametric operating limit to be a 30-day rolling average equivalent to
that 75 percent level. In a recent rule (76 FR 15736, March 21, 2011),
the EPA established 75 percent of the limit as a number that allows for
compliance flexibility and is simultaneously protective of the emission
standard, and the same technical basis is applicable here as well.
Sources whose compliance with the PM emission standard are above 75
percent of the emission limit will establish their operating limit as a
30-day rolling average equal to the average PM CPMS values recorded
during the PM compliance test. It should be noted that this provision
affects the allowable level of the parametric limit, but does not
change the PM emission limit that must be met.

B. Scaling for Continuous Parametric Monitoring of THC for Alternative
OHAP Standard

    As explained in section III.B above, the EPA is adopting a scaling
approach for parametric monitoring of THC under the alternative organic
HAP standard which is conceptually similar to the one just discussed
for parametric monitoring of PM. This provision affects the allowable
level of the THC parametric limit, but does not change the oHAP
emission limit that must be met.
    The EPA proposed the use of THC monitoring in conjunction with
organic HAP compliance testing to determine a parametric operating
limit option for monitoring continuous compliance with the alternative
organic HAP standard. In the proposed rule the organic HAP parametric
operating limit was established by correlating the highest of three
organic HAP test results with the corresponding average THC
concentration recorded by a parametric THC monitor. Industry commented
that this requirement would trigger unnecessary retests for many
facilities, especially for the best performing sources. Not wishing to
penalize those sources showing good performance, and simultaneously
wanting to be protective of the emission standard, the EPA is changing
the way parametric THC operating levels are established. Sources whose
compliance with the organic HAP emission standard are shown to be below
75 percent of the emission limit will set their operating limit to be a
30-day rolling average equivalent to that 75 percent level. Sources
whose compliance with the organic HAP emission standard are at or above
75 percent of the emission limit will establish their operating limit
as a 30-day rolling average equal to the average parametric THC values
recorded during the organic HAP compliance test. Sources with an in-
line kiln/raw mill will use the fraction of time the raw mill is on and
the fraction of time that the raw mill is off, and calculate this limit
as a weighted average of the THC levels measured during raw mill on and
raw mill off testing.

C. Work Practice Standard in Lieu of Numerical Emissions Limits for
Periods of Startup and Shutdown

    Under section 112(h) of the Act, the EPA may adopt a work practice
standard in lieu of a numerical emission standard only if it is ``not
feasible in the judgment of the Administrator to prescribe or enforce
an emission standard for control of a hazardous air pollutant''. This
phrase is defined in the Act to apply to any situation ``in which the
Administrator determines that * * * the application of measurement
methodology to a particular class of sources is not practicable due to
technological and economic limitations.'' CAA section 112(h)(1) and
(2). In adopting numerical limits for startup and shutdown in the 2010
final NESHAP, the EPA rejected comments that it should adopt work
practices as a standard during startup and shutdown. This was largely
because the commenters had not addressed the issue of whether the
requirements of section 112(h) had been met. See docket item EPA-HQ-
OAR-2002-0051-3464, pp. 183-84. The EPA later denied petitions to
reconsider this issue on the grounds that the agency had already
provided ample opportunity for comment on the issue, which petitioners
had used. See 76 FR at 28323. The DC Circuit dismissed all challenges
to the startup and shutdown provisions in the NESHAP (665 F 3d at 189).
The EPA granted reconsideration on several technical issues related to
startup and shutdown--specifically, monitoring of mercury and PM during
startup and shutdown and having an HCl limit of zero for kilns not
equipped with CEMS (see 76 FR at 28325), but these issues are no longer
relevant based on the approach adopted in this final rule.
    In the proposed reconsideration rule, the EPA proposed to retain
the numerical standards, but to use recordkeeping rather than
measurements to document compliance with the numerical standard. 77 FR
42382-83. EPA further solicited comment ``on whether the numeric
standards during startup and shutdown should be amended to provide work
practices'', and suggested what potential work practices might be. Id.
at 42383. Some commenters supported retention of numerical standards,
stating that nothing in the record supports a decision by the EPA that
numeric standards are not feasible to measure. However, these
commenters provided no supporting technical data. We also received
comments opposing numeric limits and supporting work practices in their
stead. Commenters stated that any numeric limit should be based on
actual data gathered during startup and shutdown, which the proposed
limits are not, and that measurement of emissions during startup and
shutdown poses significant technical problems, mainly based on CEMS
calibration issues, and the duration of startups and shutdowns.
    Industry has presented information specific to the cement industry
to the EPA on technical issues associated with cement kilns measuring
PM, mercury, THC and HCl during periods of startup and shutdown. See
docket item EPA-HQ-OAR-2011-0817-0237[1] and PCA Meeting 9-15-11
monitoring presentation in the docket for this rulemaking, as well as
their public comments. EPA has continued to evaluate these data. In
light of all of these public comments and further evaluation of the
data, the EPA has decided to establish work practice standards in lieu
of numeric standards during startup and shutdown periods. The EPA is
doing so because the application of measurement methodology is not
practicable for technological and economic reasons. See CAA section
112(h)(2)(B).
    The operation of kilns at cement manufacturing plants is different
from many other sources. Kiln startups can last days, during which time
fuels are switched and temperatures and moisture conditions fluctuate
substantially. Also, cement kilns have two types of inputs--raw feed
that is changed into clinker in the kiln, and kiln fuel. The cement
kiln is sized to accommodate not just exhaust gas flow from combustion,
but the gases evolved from the calcination of limestone and moisture
that evaporates from the kiln feed. As a result of these factors, the
difference in gas flow characteristics of a cement kiln during steady
state operation and startup/shutdown is more pronounced than that for
other combustion source categories. In addition, cement kilns begin
introducing feed as part of the startup process which further
exacerbates the transient and fluctuating nature of these

operations not only because of the impact of this feed on the exhaust
gases, but because raw materials and fuels are introduced at opposite
ends of the kiln, which results in countercurrent flow of the solid
material in the kiln and kiln exhaust gas, increasing the turbulence,
transience and fluctuating conditions. The result is that conditions
change constantly when cement kilns are in startup or shutdown mode.
These conditions make stack measurements, both manual and continuous,
for this source category unreliable because the constant shifting in
conditions prevents any stack measurement from being representative of
anything but conditions at that precise moment. For that reason manual
stack tests, which take place over a period of a few hours, would not
be presenting accurate information, since they would not be reliably
measuring conditions across the duration of the test.
    There is no way to craft a testing regime to compensate for these
testing issues at each kiln in a manner that can produce reliable and
replicable results. Such modifications would be specific to that
individual startup event--i.e. ad hoc and therefore not of general
applicability or utility in showing compliance. Continuous measurements
conducted during these periods for cement kilns are also subject to
inaccuracies resulting from these rapidly changing conditions. The
temperature changes of greater than one thousand degrees Fahrenheit,
flue gas moisture changes greater than 20 percent, and gas flow changes
over several thousand cubic feet per minute, as well as other factors
such as flue gas molecular weight swings, combine to create a complex
matrix of measurement variables not accounted for in a cement kiln CEMS
installation. That is, CEMS for PM, HCl, Hg, and THC are not able to
reliably accommodate all of these transient shifting variables when
measuring cement kiln startup and shutdown emissions. As noted above,
these issues are further exacerbated by the fact that cement kilns have
multiple inputs (fuel and feed), and the clinker production process
generates higher gas flows than would be expected based on just the
fuel inputs. This fact also means that flue gas flow rates cannot be
accurately calculated from fuel inputs alone.
    The EPA regards situations where a measurement may yield a value
which is analytically suspect, which is the case for cement kilns
during startup and shutdown for the reasons just described, as being a
situation where measurement is not ``technologically practicable''
within the meaning of section 112(h)(2)(B) of the Act. Unreliable
measurements raise issues of practicability and of feasibility and
enforceability (see section 112(h)(1)).\4\
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    \4\ The application of measurement methodology during cement
kiln startup and shutdown would also not be ``practicable due to * *
* economic limitation'' within the meaning of section 112(h)(2)(B)
since it would just result in cost expended to produce analytically
suspect measurements.
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    The EPA is not finalizing its proposed approach of setting
numerical emission limits for startup and shutdown and requiring that
sources certify compliance with those limits by keeping certain records
certifying that they used certain fuels and did not introduce feed into
the kiln. Under the proposal, sources would have had to certify
compliance with the standards for the various organics based on assumed
combustion conditions. As pointed out persuasively in the public
comments, combustion conditions during startup and shutdown are too
widely varying to either reliably measure or calculate emissions
because combustion conditions change widely during startup and
shutdown, sources indicated that they could not certify compliance
based on an assumed combustion condition. See docket item EPA-HQ-OAR-
2011-0817-0506, p. 11 (``Until ideal combustion conditions can be met
in the combustion chamber (adequate temperature and turbulence), the
combustion process will be incomplete. While this should not impact
fuel-derived hazardous air pollutants (chlorine and mercury), it will
impact the emissions of organics and possibly PM''). In light of the
measurement issues noted above and the fact that sources could not
certify compliance under the proposed approach, the EPA is not
finalizing the proposed approach of setting numerical limits for
startup and shutdown and allowing sources to certify compliance with
the limits by maintaining certain records.
    Instead, for the reasons explained above, the EPA is establishing
work practice standards to demonstrate compliance with startup and
shutdown. The work practices that apply during startup and shutdown are
as follows:
     During startup the kiln must initially use any one or
combination of the following clean fuels: Natural gas, synthetic
natural gas, propane, distillate oil, synthesis gas, and ultra-low
sulfur diesel until the kiln reaches a temperature of 1200 degrees
Fahrenheit.
     Combustion of the primary kiln fuel may commence once the
kiln temperature reaches 1200 degrees Fahrenheit.
     All air pollution control devices must be turned on and
operating prior to combusting any fuel.
     You must keep records as specified in Sec.  63.1355 during
periods of startup and shutdown.
    For the purpose of identifying when the kiln is in a startup/
shutdown mode and subject to work practices and when the kiln is
subject to numerical emission limits, we are defining the beginning and
ending of startup and shutdown. At proposal we defined startup as when
the kiln's induced fan is turned on and shutdown was defined as
beginning when feed to the kiln is halted. Commenters noted that a kiln
may have the induced draft (ID) fan operating even when the kiln is
completely shutdown, no fuel is being burned, and there is no potential
for emissions. Therefore, we changed the startup definition to be when
a shutdown kiln turns on the ID fan and begins firing fuel in the main
burner, because this is the point where the potential for emissions to
occur begins. Startup ends when feed is being continuously introduced
into the kiln for at least 120 minutes or until the feed rate exceeds
60 percent of the kiln design limitation rate. We added the duration/
load element to the definition of startup because during startup a kiln
must begin adding feed material to achieve steady state operation.
After feed is first introduced it requires up to two hours or
sufficient feed to achieve 60 percent of maximum operation to achieve a
representative steady-state condition. (See meeting notes, PCA November
28, 2012, in the docket for this rulemaking). Shutdown begins when
continuous feed to the kiln is halted and ends when the kiln rotation
ceases.
    We believe these work practices, which include the requirement that
all air pollution control devices be operating, will ensure that
emissions during startup and shutdown will be lower than the standards
that apply during steady state operations, given use of cleaner fuels,
minimal raw material inputs, and operation of all control devices
during these periods. See 77 FR 42382 (noting that emissions during
startup and shutdown would be expected to be lower than during steady
state operations for these reasons).

V. Summary of Significant Comments and Responses

A. Amendments to Existing Source and New Source Standards for PM Under
CAA Sections 112(d) and 111(b)

1. Changes to Level and Averaging Time of Existing Source NESHAP
    The EPA proposed to amend the existing and new source standards for
PM. The floor for the existing source standards increased from 0.04 lb/
ton clinker to 0.05 lb/ton clinker as a result of removing CISWI kilns
from the database. See Section 8.3, Portland Cement Reconsideration
Technical Support Document, June 15, 2012, Docket item EPA-HQ-OAR-2011-
0817-0225; see also 77 FR 42372/3. Second, the EPA proposed to change
the compliance regime for the standard from use of PM CEMS to stack
testing, a consequence being that the standard would no longer be
expressed as a 30-day average but rather as the average of three test
runs. The EPA thus proposed to express the recalculated floor (i.e.
0.05 lb/ton clinker 30-day average resulting from the reanalysis) as
.07 lb/ton of clinker (average of three test runs). The 0.07 lb/ton
clinker standard expresses the recalculated floor (i.e. 0.05 lb/ton
clinker) as a not-to-exceed value based on stack testing, using the
Upper Prediction Limit equation to do so. See Portland Cement
Reconsideration Technical Support Document, June 15, 2012, Docket item
EPA-HQ-OAR-2011-0817-0225.\5\
---------------------------------------------------------------------------

    \5\ One commenter inaccurately stated that the proposed rule
would essentially double the PM standard. As just explained, the
existing source floor (and standard) increased from 0.04 30-day
average to 0.05 lb/ton clinker 30-day average as a result of
removing CISWI kilns. As a not-to-exceed standard, that same level
is expressed as 0.07 lb/ton clinker, the higher level reflecting the
greater variability involved when basing the standard on the average
of the three test runs rather than on 30 days of measurements.
---------------------------------------------------------------------------

    The EPA further proposed to use CPMS for continuous parametric
monitoring. This system responds to changes in PM concentration and
generates a corresponding milliamp output signal. 77 FR 42376-77. The
proposed PM parametric level was correlated to the highest recorded
value during three test runs. A source would meet this site-specific
level on a 30-day rolling average. Failure to meet this 30-day rolling
average would result in retesting, and more than four deviations from
the parametric level in a year would be presumed (subject to
possibility of rebuttal by the source) to be a violation of the
emission standard itself. See 77 FR 42377.
    Our proposal to change the compliance regime from use of CEMS to
stack tests reflected technical issues related to a PM CEMS'
reliability with measuring the Portland cement PM standard.
Specifically, the EPA discussed the reliability of measurements,
obtained using PM CEMS calibrated as required by the mandated PS 11,
below the level of the 2010 standard or the level of the recalculated
PM floor. See 77 FR 42374-76. The EPA's judgment at proposal was that
as a result of PM measurement uncertainties, ``this correlation will
not be technically or practically achievable for a significant number
of cement kiln sources.'' Id. at 42376.
    One commenter challenged the necessity of amending the standard to
a stack test regime (apparently not realizing that the existing source
standard also changed as a result of removing CISWI kilns from the
database). First, the commenter maintained that the EPA has no
authority to voluntarily change a promulgated MACT standard to make the
standard less stringent, based on the language of section 112(d)(7).
The commenter further maintained that the EPA had not definitively
shown that PM CEMS calibrated pursuant to PS 11 could not be used to
reliably measure the Portland cement PM standard. Specifically, the
commenter stated that the various problems identified by the EPA at
proposal are amenable to resolution by testing longer and more often,
and argued that the EPA essentially admitted as much at proposal. The
commenter noted that other technical problems, like the difficulty of
accounting for varied particle sizes, could be resolved by using a beta
gauge CEMS. The commenter dismissed the EPA's technical reservations on
these issues as arbitrary speculation. The commenter also stated that
PM CEMS are already in successful use by cement plants both in this
country and overseas. The commenter further believed that the EPA could
resolve these technical issues by amending the PM CEMS Performance
Specification rather than by amending the averaging time of the PM
standard and changing its compliance basis.
    In response, we note first that we do not accept the commenter's
legal argument based on section 112(d)(7). Section 112(d)(7) states
that ``[n]o other emission standard * * * under this section shall be
interpreted, construed or applied to diminish or replace the
requirements of a more stringent emission limitation or other
applicable requirement established pursuant to section 111 of this
title, part C or D of this subchapter, or other authority of this
chapter or a standard issued under State authority.'' Although the
commenter maintained that this provision unambiguously bars the EPA
from amending the promulgated NESHAP to make it less stringent, we
disagree. Indeed, it is hard to read the statutory language in such a
way. On its face, the provision indicates that a section 112(d)
standard does not supplant more stringent standards issued under some
authority other than section 112(d). Nor does the commenter's
interpretation make sense. It would bar the EPA from amending a section
112(d) standard that was technically deficient or incorrect. This
cannot have been Congress' intent when adopting the technology-based
section 112(d) MACT regime.\6\ Moreover, when Congress adopted anti-
backsliding provisions in the CAA, it did so explicitly. See CAA
sections 172(e); 110(l); and 193. There is no such explicit language in
section 112(d)(7). Thus, the EPA does not read section 112(d)(7) as
precluding amendments to MACT standards which result in numerically
less stringent standards, provided of course, that such standards are
technically justified and otherwise consistent with the requirements of
the Act.
---------------------------------------------------------------------------

    \6\ The commenter cites no legislative history to support its
reading, nor is EPA aware of any.
---------------------------------------------------------------------------

    The commenter is also mistaken in asserting that sources can simply
utilize PM CEMS not correlated to PS 11. The PS 11 requirements apply
to all PM CEMS used by a cement kiln. See sections 63.1349(b)(1)(A) and
1350 (b)(1) from the 2010 final rule (75 FR 55057, 55059).\7\
---------------------------------------------------------------------------

    \7\ It also makes no sense to use PM CEMS not subject to a
uniform calibration protocol. The results obtained would not be
comparable.
---------------------------------------------------------------------------

    With regard to the technical issues raised by this commenter, the
EPA explained in detail at proposal the problems of correlating PM CEMS
under PS 11 at cement plants (see 77 FR 42374-42377). These obstacles
are not resolvable simply by measuring more often and longer, as the
commenter maintains. Extending the duration of the Method 5 test gives
this reference method additional opportunity to collect more sample
mass, but this is no guarantee that the time added to the test will
collect enough particulate mass to resolve detection issues, especially
when testing is conducted at the better performing (lower emitting)
sources. Longer test runs inherently increase the variability of the PM
CEMS data collected during the test, which may cause further
difficulties with the

correlation between instrument and reference method. Nor does
conducting a higher number of reference method tests resolve the
difficulties with PS 11 correlation created by greater uncertainty in
the reference method at low levels. Put another way, more tests with
high uncertainty and poor correlation do not improve the likelihood of
passing PS 11 as there is no expectation of improving the mathematical
relationship between the reference test and the instrument.
Furthermore, PS 11 section 8.6 requires a minimum number of fifteen
tests to develop a correlation curve, with no limit to the maximum
number. Considering more than 15 tests when developing the correlation
creates much difficulty in developing a precise mathematical
relationship. Sources are allowed to discard 5 runs for any reason they
wish, but must present at least 15 test runs for the correlation
calculation. Id. As a source increases the number of test runs beyond
20, any additional runs must be included in the correlation equation
and at that point the ability of a source to satisfy PS 11 becomes more
hampered with every test run.
    The EPA noted that special problems are posed by the size and
variability of cement kiln-generated particulate. The EPA also noted
that the standard light-scintillation type of PM CEMS would likely
encounter higher variability for the same PM concentration, and have
difficulty satisfying correlation protocols as a result. The EPA noted
that beta gauge CEMS could potentially resolve at least some issues
related to cement particle variability but noted further that these
devices were largely untested in the cement industry, and none (so far
as the EPA is aware) has successfully completed a PS 11 certification.
See 77 FR 42375/3. The commenter maintains that the existence of beta
gauge CEMS resolves all questions as to their reliability in the cement
industry, but the EPA reiterates, as it did at proposal, that there
needs to be some assurance of the reliability of that methodology to
certify with PS 11 at low levels (as required by this final rule). That
information does not presently exist. The commenter states that the EPA
is being speculative as to potential difficulties with a different CEMS
technology, but relative to Portland cement sources, it would be
speculative to assume that beta gauge CEMS would successfully pass a PS
11 certification to reliably and quantifiably measure compliance with
the NESHAP, especially at the very low PM levels at some of the sources
in the cement source category.
    The commenter also maintains that Tapered Element Oscillating
Microbalance (TEOM) devices could be used in place of light
scintillation PM CEMS. A TEOM is a device that uses a very thin,
tapered, element vibrating at a known frequency that has a first
principle relationship to the measurement of mass. Particles that
impact the element also impact the harmonic vibration of the sensor
which can be translated to a measurement of the particle mass. This is
a more direct approach to measuring the actual mass of PM in stack gas,
and has shown promise to operate very consistently at low levels in
laboratory conditions. Several TEOMs are currently used for monitoring
ambient PM levels at several non-cement, non-domestic industry
installations. TEOMs that are capable of measuring stack gas are not
currently available for sale in the U.S., though this may change in
future years. Even so, with a monitor capable of more direct mass
measurement of PM in stack gas, using PS 11 to certify one against
Method 5 may be problematic at low PM concentrations. The EPA currently
has no data to assess TEOM capabilities versus Method 5 at very low PM
concentrations such as those presented by the better performing sources
in this category. Were TEOM instrumentation commercially available, the
EPA would need to conduct a re-evaluation of PM CEMS technology that
included TEOM data to determine if this instrument could overcome the
challenges posed by calibration with Method 5 at the very low PM levels
emitted by some of the sources in the cement source category. As just
explained, it is not speculation, but rather legitimate engineering
caution that makes it appropriate not to require compliance with a rule
based on an untested measurement methodology.
    The commenter further maintains that rather than amend the standard
to change the compliance test methodology and averaging time, the EPA
should revise PS 11 instead, evidently assuming that a revision can be
done rapidly. The commenter's assumption is mistaken. Performance
specification development is a process that takes multiple years and
involves data collection on types of technologies, field testing,
comparison to reference measurement methodology, workgroup and
stakeholder meetings, peer review, rule proposal and public comment
period, as well as comment response and final promulgation of the
Performance Specification. With the development of PA 12A for Mercury
CEMS, the EPA invested a budget in excess of one million dollars to
conduct technology and field studies, as well as to refine the
analytical techniques and work through stakeholder concerns prior to
proposal of the Performance Specification. The process from inception
to final promulgation took over 5 years to complete. PS 11, at issue
here, was over 3 years in development, from concept to final
promulgation, and involved a budget of $250,000. Based on this past
history, it is likely to result in a delay of 3 years or more were the
EPA to delay promulgation of this final rule until we could undertake
the process to research, propose and finalize solutions to PS 11 that
may ameliorate some of the issues vis-a-vis the cement industry now
present. Furthermore, such a process would not address the issues
relating to measurement uncertainties using Method 5 at low PM
concentration levels near its detection limit (i.e. below its practical
quantitation limit of 3 mg), and so there would remain significant
technological hurdles to clear before the EPA could require the use of
PM CEMS in respect to this final rule.
    The commenter points to PM CEMS use by European cement kilns. This
is a misplaced comparison. The European calibration and certification
of this instrumentation is completely different than PS 11 requirements
developed by the EPA. European monitoring is certified in a laboratory
environment, and calibrated on site by the instrument vendor when
installed. The EPA has a long history of requiring CEMS installations
in the USA to meet more rigorous calibration and performance
specification certification through a series of comparisons to
reference Method 5 test measurements conducted on the stack with the
flue gas matrix at the facility, not in a controlled laboratory. For a
PM CEMS, this would be a correlation developed with Method 5 as
described in PS 11. The two certification regimes differ greatly in
approach and simply adapting European certification standards to USA
facilities does nothing to mitigate this difference.
    In summary, the EPA has carefully considered the issue and it is
our engineering judgment that the PS 11 correlation will not be
technically or practically achievable for a significant number of
cement kiln sources. This is due to the combination of the low
emissions concentrations, PM CEMS measurement uncertainty factors, the
variability in composition of cement PM, and need for extraordinarily
long test runs to reduce Method 5 uncertainty to a level that provides
normal measurement confidence (i.e. greater than the 3 mg practical
quantitation level of Method 5), plus the

compounding uncertainties associated with source operational
variability. The EPA further recognizes that these problems in
developing PS 11 correlations are most likely to adversely affect the
lowest emitting sources in the category and are more likely to result
in violations of the rule more often for these sources than for sources
operating with higher PM emissions. This result would obviously be
environmentally counterproductive. We are therefore amending the
standard to be based on stack testing, and expressing the standard as a
not-to-exceed (i.e., stack test Method 5 or 5I) standard of 0.07 lb/ton
clinker.\8\
---------------------------------------------------------------------------

    \8\ Because the EPA believes that these same issues pertain to
measurements of the section 111(b) new source performance standard
for modified sources, and because further controls would be both
costly and not cost effective (see section V.A.3 below), the EPA is
adopting the same amendment for modified new sources under the NSPS.
---------------------------------------------------------------------------

    Additional responses regarding these issues, including responses to
issues raised in the comments from industry, are found in sections 3
and 4 of the Response to Comment document, which is found in the docket
for this rulemaking.
2. Issues Related to Use of CPMS for Parametric Monitoring
    To document continuous compliance with the Method 5 standard (i.e.,
parametric monitoring designed to monitor proper operation of PM
controls), the EPA proposed that PM be monitored continuously using a
CPMS. See 77 FR 42376-77. The parametric limit was to reflect the
highest of the three method 5 test runs from the stack test, and would
be averaged over 30-days. The EPA further proposed corrective action
requirements in the event of exceeding the 30-day rolling average
parametric limit, and a rebuttable presumption that four such
exceedances in a calendar year showed a violation of the emission
standard itself.
    With respect to the use of CPMS technology, the EPA has recognized
that PM CEMS technology cannot meet PS 11 requirements in all Portland
cement installations, yet the EPA has also recognized that PM CEMS
sensors are more sensitive and better at detecting small differences in
PM concentration than other technologies such as opacity monitors
(http://www.epa.gov/ttn/emc/cem/pmcemsknowfinalrep.pdf) In considering
the use of PM CEMS at Portland cement facilities we find that while
using PM CEMS technology for continuous quantitative measurement of PM
concentration as correlated to Method 5 with PS 11 is frequently not
achievable (as stated in the preceding subsection of this preamble),
using the same technology for continuous qualitative measurement of PM
emissions is practicable in every instance. Given the information we
have that shows PM CEMS technology to be more sensitive to in-stack PM
concentration differences than opacity monitors and nepheolmeters, the
EPA sees a distinct advantage in using these technologies for
continuous parametric PM monitoring, rather than measuring some other
parameter.
    In using a PM CEMS as a CPMS to conduct continuous qualitative
monitoring of PM concentration in the stack, we are not interested in
specific output information from the instrument (e.g. lbs/ton clinker).
We only need to know that PM concentration increases or decreases. The
signal output from the instrument need not be correlated to PM
concentration through PS 11 trials to achieve this, but rather we can
accept the native signal output from the instrument, as is, in
milliamps, and track that signal to determine trends in PM emissions.
In this final rule we are requiring PM CPMS instruments to employ a 4-
20 milliamp output, which is a standard electronic signal output common
to many CEMS.\9\ With a PM CPMS the milliamp output would not represent
an opacity value, but like an opacity analyzer, the milliamps would
increase as PM concentration increases and decrease as PM concentration
decreases. We can then monitor the milliamp signal while conducting a
Method 5 performance test and correlate the average milliamp signal to
the average PM concentration during the testing. This relationship is
notably coarser in terms of understanding the precise PM concentration
in the stack, but the instrument's sensitivity to changing PM
concentration in the stack, and its changing milliamp signal output,
does not deteriorate and may still be employed to qualitatively monitor
PM emissions.
---------------------------------------------------------------------------

    \9\ For example, an opacity instrument uses a series of filters
to calibrate the analyzer and produce a ``percent opacity'' output.
Twenty five percent opacity likely correlates to a milliamp value
near eight milliamps, or 4 milliamps plus 25 percent of the
difference between 4 and 20 milliamps (again, 4 milliamps). Fifty
percent opacity would represent a signal near 12 milliamps, and so
on, with 20 milliamps representing a signal of 100 percent opacity.
---------------------------------------------------------------------------

    The EPA received numerous comments about our proposed PM CPMS
parametric monitoring approach. Industry commenters maintained that
sources would have to continually retest unnecessarily, since CPMS
measure an increase in PM CPMS values. This increase in PM CPMS values
would (or at least, could) denote a modest rise in PM emissions, but
actual stack emissions of PM could still be well below the limit. The
EPA recognizes this concern as creating additional burden for
facilities exhibiting good control of their PM emissions (see section
IV.A above), and, therefore, we have modified the process by which a
source would establish and comply with their PM CPMS operating limit in
this final rule. In doing so we considered scaling options for PM CPMS
signals, as they correspond with PM emissions, that were proposed by
industry but found the options presented were not protective enough of
the emission standard. After extensive analysis (see S. Johnson, memo
to docket number EPA-HQ-OAR-2011-0817, ''Establishing an Operating
Limit for PM CPMS'', November 2012), we are promulgating a scaling
factor of 75 percent of the emission limit as a benchmark. See section
IV.A above. As in the proposed rule, every source will need to conduct
an annual Method 5 test to determine compliance with the PM emissions
limit, and during this testing will also monitor their PM CPMS milliamp
output. Sources which emit PM less than 75 percent of their emission
limit will be able to scale their PM CPMS milliamp output to determine
where their PM CPMS would intersect 75 percent of their allowed PM
emissions, and set their operating level at that milliamp output. This
alleviates many re-testing concerns for sources that operate well below
the emission limit and provides them with greater operational
flexibility while still assuring continuous compliance with the PM
stack emission standard. It also creates an incentive for sources to
select high efficiency PM controls when sources are evaluating
potential compliance strategies.
    For sources whose Method 5 compliance tests place them at or above
75 percent of the emission standard, their operating level will be the
average PM CPMS milliamp output during the three Method 5 test runs.
This means their operating level is the milliamp output that correlates
to their PM compliance determination, and not the highest average 1
hour run value that was in the proposed rule. Now that we are adopting
a scaling factor, we no longer believe that it is also appropriate to
establish the parametric limit based on the highest of the three runs
(which moreover, could reflect a level higher than the level of the
standard). Moreover, as noted below, we believe that on balance the 30
days of averaged

CPMS measurements provides ample operating cushion.
    In a recent rule (76 FR 15736, March 21, 2011), the EPA established
75 percent of the limit as a number that allows for compliance
flexibility and is simultaneously protective of the emission standard.
In this final rule we are utilizing that value so as not to impose
unintended and costly retest requirements for the lowest emitting
sources and to provide for more cost effective, continuous, PM
parametric monitoring across the Portland cement sector. This approach
was selected from among many considered as it provides the greatest
amount of flexibility while demonstrating continuous compliance for
sources which are the lower emitters in the category and is also
effective in holding higher emitters to the emission standard. With
this parametric monitoring approach in place we expect sources to
evaluate control options that provide excellent PM emissions control
and provide them greater operational flexibility below the standard.
    One commenter maintained that the use of a CPMS for parametric
monitoring would be ``egregious'' since the milliamp output of the CPMS
allowed a source to select operational parameters of tangential
relation to PM emissions and would therefore not provide useful
information as to proper PM control. The commenter also stated that
monitoring of opacity would be preferable. An industry commenter
likewise requested that continuous opacity monitors or bag leak
detectors be used rather than CPMS.
    The EPA does not agree with these comments. First, the milliamp
output of the CPMS reliably and sensitively indicates increasing or
decreasing PM concentration in the stack. Where PM controls are
failing, the PM CPMS signal will indicate the increasing concentration
of PM in the stack. A source will need to monitor the trend from the PM
CPMS daily reading to maintain compliance with the 30-day emission
standard. Indeed, the EPA has sufficient confidence that four
exceedances of the CPMS continuous measurements is a presumptive
violation of the emission standard itself. Moreover, the CPMS is
considerably more sensitive than an opacity monitor or bag leak
detector at detecting fluctuations in PM level. An opacity monitor
determines the percent of a light signal that is occluded across the
stack diameter. Opacity analyzers operate on a zero to 100 percent
scale, meaning they are capable of registering PM that completely
occludes the far stack wall from the instrument light source. This
amount of PM is roughly equivalent to a complete failure of the
emission control device. A properly operating control device will emit
five percent opacity or less, which is barely visible to the naked eye
and on the low end of the opacity monitor capability. PM emissions that
increase opacity two percent at this level may well exceed the emission
standard, yet they only mildly deflect the opacity monitor output. This
same 2 percent opacity increase is capable of registering changes of
several milliamps on a PM CPMS when operating on the scale provided in
this final rule. With several decimal fractions available between each
milliamp to track signal output, and three or four milliamps
representing 1 percent opacity, the PM CPMS has a clear advantage in
low PM concentration measurement over continuous opacity monitoring
systems. Regarding baghouse leak detectors, the EPA has no information
that shows them operating on the same sensitivity level as PM CPMS
technology, and we do not require baghouse leak detection systems on
sources where PM CPMS are in use for this reason.
    Industry commenters objected to the proposal that 4 calendar year
exceedances \10\ from the parametric limit would be a presumptive
violation of the emission standard. Again, the EPA does not agree.
First, the EPA may permissibly establish such a presumption by rule,
assuming there is a reasonable factual basis to do so. See Hazardous
Waste Treatment Council v. EPA, 886 F. 2d 355, 367-68 (DC Cir. 1989)
explaining that such presumptions can legitimately establish the
elements of the agency's prima facie case in an enforcement action.
Second, there is a reasonable basis here for the presumption that four
exceedances (i.e. increases over the parametric operating limit) in a
calendar year are a violation of the emission standard. The parametric
monitoring limit is established as a 30-day average of the averaged
test value in the performance test, or the 75th percentile value if
that is higher. In either instance, the 30-day averaging feature
provides significant leeway to the owner operator not to deviate from
the parametric operating level since the 30 measurements will
significantly dampen variability in the single measurement (average of
three test runs) that produced the parametric value. See 77 FR 42377/2
and sources there cited. The EPA acknowledges that the difference was
even greater between the parametric level and the emission standard in
the proposed rule (which was based on the highest measured test run).
The EPA believes that the 30-day averaging feature plus the 75-percent
scaling feature for the lower emitting sources now provides a
sufficient operating cushion. See 77 FR 42377.
---------------------------------------------------------------------------

    \10\ In the proposed rule, the EPA referred to a measurement
higher than the parametric limit as a ``deviation'' and proposed a
definition of deviation. See 77 FR 42398. The EPA is not including
this terminology in this final rule. The term ``deviation'' is not
in the Portland cement NESHAP rules (which date back to 1998), and
has not proved necessary in practice. More important, the rule
itself states what the consequences of measurements which exceed a
parametric limit are (i.e. retesting, and in some instances, a
presumptive violation of the emission standard itself), so that no
further general regulatory provision (i.e. a generalized definition
of `deviation' or similar term) is necessary.
---------------------------------------------------------------------------

3. Existing Source Beyond the Floor Determination
    The EPA proposed to use the floor levels for PM as the standard,
rejecting more stringent standards on the grounds of poor cost
effectiveness (after considering non-air environmental impacts and
energy implications of a more stringent standard as well). See 77 FR
42376. One commenter argued that the EPA should adopt a beyond the
floor standard for PM, maintaining that such a standard was justified
under the factors set out in section 112 (d)(2).
    The EPA disagrees, and is not adopting a beyond the floor standard.
After considering the cost of the emission reductions attributable to
such a standard, and the associated non-air and energy impacts of such
a standard, the EPA determines that the standard is not ``achievable''
within the meaning of section 112 (d)(2). Specifically, the EPA
estimates that a beyond the floor standard set at the level of the
original (2010 final rule) standard would only result in 138 tpy--
nationwide--of PM reduction (a value not questioned by any of the
commenters). See Final Portland Cement Reconsideration Technical
Support Document, December 20, 2012. We further estimate that the cost
of achieving this modest incremental reduction would be approximately
$37 million (the estimated cost savings attributable to the amended PM
standard (including savings attributable to ancillary PM controls
related to collection of PM from the control of Hg, THC, and HCl). See
Final Portland Cement Reconsideration Technical Support Document,
December 20, 2012, included in the rule docket, EPA-HQ-OAR-2011-0817.
These total costs are high compared to the small nationwide emission
reductions, and the cost effectiveness of these reductions is
correspondingly high: approximately $268,000 per ton of PM removed.
This is significantly higher cost effectiveness for PM than the EPA has
accepted in other NESHAP

standards. See 76 FR 15704 (March 21, 2011) (rejecting $48,501 per ton
of PM as not cost effective for PM emitted by CISWI energy recovery
units); see also 72 FR 53814, 53826 (Sept. 20, 2007) (proposing (and
later accepting) cost effectiveness of $10,000 per ton for PM as
reasonable in determining Generally Available Control Technology, and
noting that the EPA had viewed cost effectiveness only as high as
approximately $31,000 per ton as reasonable under its Title II program
for mobile sources). A beyond the floor standard at the level of the
2010 standard would also involve slightly higher energy use, although
this is not a major factor in EPA's decision. EPA is therefore not
adopting a beyond the floor standard for PM at the level of the 2010
standard. A standard even more stringent would likewise not be
justified. See 76 FR 54988.\11\
---------------------------------------------------------------------------

    \11\ The commenter's argument that section 112 (d)(2)'s
requirement that the EPA consider ``the cost of achieving such
emission reduction'' limits the EPA to considerations of economic
achievability, and not cost effectiveness, is misplaced. See
Husqvarna AB v. EPA, 254 F. 3d 195, 200 (DC Cir. 2001) (cost
effectiveness properly considered in evaluating cost of compliance
under CAA section 213, a technology-based provision similar to
section 112 (d)(2)). The commenter's further argument that the
requirement in section 112 (d)(2) for standards to result in ``the
maximum degree of reduction in emissions of hazardous air pollutants
* * * achievable'' considering cost and other factors constrains the
EPA's ability to consider cost-effectiveness or otherwise balance
the statutory factors has likewise been rejected. See Sierra Club v.
EPA, 325 F. 3d 374, 378 (DC Cir. 2003) (the EPA was left with great
discretion in determining how to balance such factors when
considering technology-based standards which are to result in
maximum reductions achievable).
---------------------------------------------------------------------------

4. New Source PM Standard Under Section 112(d)(3)
    One commenter challenged the methodology the EPA used in the 2010
rulemaking to establish the new source floor and standard, maintaining
that for new plants, the EPA's floors must reflect the emission level
achieved by the single best performing kiln in the category, not the
best performing kiln for which the EPA happens to have emissions
information. See section 112(d)(3). The EPA did not reopen the
methodology by which new source floors for this industry are
determined. See 77 FR 42373 n. 3 (``The EPA will not consider comments
challenging the data and methodology for the new source standards since
these are unchanged from the 2010 rule and the EPA is not reexamining
any of these issues.'') In any case, if the issue is (against the EPA's
view) deemed to be reopened, CAA section 112(d)(3) indicates that new
source floors are to be based on ``the emission control that is
achieved in practice by the best controlled similar source, as
determined by the Administrator'' (emphasis supplied). This language
affords considerable discretion for the agency to base the NESHAP new
source floors on performance of sources for which the agency has
emissions information.

B. Mercury Standard

    The EPA explained at proposal that reanalysis of the mercury floor,
after removing CISWI kilns, resulted in a floor of 58 lb/MM tons
clinker produced--slightly higher than the previously calculated floor
and standard of 55 lb/MM tons clinker produced. The EPA further
proposed to adopt 55 lb/MM tons clinker produced as a beyond-the-floor
standard. See 77 FR 42373. The new source standard was unchanged since
the standard was based on the performance of the best performing
similar source.
    The EPA is adopting the standards as proposed. One commenter
challenged the appropriateness of adopting a beyond-the-floor standard,
not for the industry as a whole, but for itself. As to this individual
plant (Ash Grove, Durkee), the commenter maintained that the cost of
attaining the three additional lb/MM ton clinker produced reduction
(i.e., the difference between 58 and 55 lb/MM tons clinker produced)
was greater than the EPA estimated because it would require more than
just additional carbon in an activated carbon injection system to
achieve the incremental difference. According to the commenter, they
have performed extensive testing and the addition of activated carbon
per million actual cubic feet per minute of exhaust gas has little or
no impact on mercury emissions. The commenter states that for plants
such as Ash Grove's Durkee plant, there is no known add-on control
technology at this time that will assure achievement of the standard on
a continuous basis.
    We note first that the commenter is somewhat over-estimating the
incremental reduction of mercury actually needed. To achieve the
emission standard, sources will need to operate their processes and
controls so that they can achieve the average emissions level used in
setting the existing source limit of 55 lb/MM ton--the so-called design
level. See e.g. 77 FR 42389/3 (estimating emissions attributable to
this final rule based on design levels); see also discussion of design
values in section VI.B below. That level is 31.7 lb/MM ton for the
standard of 55 lb/MM ton. See 75 FR 54976/3. The average for the 58 lb/
MM ton is 34.1 lb/MM ton. The additional reduction needed is therefore
2.4 lb/MM tons, not 3 lb/MM tons as stated by the commenter.
    As the EPA has acknowledged repeatedly, due to the high levels of
mercury in their limestone, mercury emissions from the Ash Grove Durkee
plant are not typical of other plants in the industry. See, e.g. 75 FR
54978-79. As a result, this plant faces a particularly great challenge
in meeting the mercury standard, whether the standard is 55 or 58 lb/MM
tons. Because of their unique situation, we do not believe that the
difficulties this facility is having in meeting the mercury standards
can be generalized to the rest of the industry. Section 112(d)(2) of
the Act posits an industry-wide standard. Having said this, our cost
analysis conducted for the 2009 proposal and 2010 final rule assumed
that this plant would have to install multiple control systems in order
to meet the limit for mercury. See Docket item EPA-HQ-OAR-2002-0051-
3438. Therefore, if in this particular case the activated carbon
injection (ACI) system cannot achieve the small additional reductions
required, then the facility has other mercury control options available
such as further dust shuttling, or treating cement kiln dust to remove
mercury. Dust shuttling entails moving dust from within the kiln to
other parts of the process and is considered a closed loop process,
thereby not causing any waste impacts. In addition, any costs
associated with dust shuttling have already been accounted for in the
cost estimates the EPA has developed for this particular facility.
    The commenter alluded to control performance data that it shared
with the EPA. We note that the commenter has provided pilot scale data
as part of the 2010 rulemaking (see Docket item EPA-HQ-OAR-2002-0051-
2073), but has not provided data on the effects of increasing carbon
injection on mercury emissions for a full scale facility. We note that
in the electric utility industry, where there is significantly more
experience with ACI, it is well established that higher carbon
injection rates increase mercury removal (Sjostrom, S.; Durham, M.;
Bustard, J. Martin, C.; ``Activated Carbon Injection for Mercury
Control: Overview'', FUEL, 89, 6, 1320 (2010)). There is no data to
indicate that ACI systems in the cement industry would behave
differently than those in the utility industry. Given the lack of data
on the efficacy of increasing carbon injection rates on mercury removal
for full scale cement operations, we cannot conclude that increasing
carbon injection is not a

reasonable approach for increasing mercury removal efficiency.

C. Standards for Fugitive Emissions From Open Clinker Storage Piles

    The EPA proposed that cement kilns control fugitive emissions from
open clinker storage piles, defined at proposal as ``any clinker
storage pile that is not completely enclosed in a building or
structure''. These piles would be controlled through the use of work
practices which minimized emissions by means of (among others) partial
enclosure, damping down the pile by chemical or physical means or
shielding piles from wind. These work practices were drawn from permits
for existing cement kilns, and every cement kiln appears to already be
utilizing some type of work practice to minimize fugitive emissions
from open clinker storage piles. See 77 FR 42378. Cement kiln sources
were allowed to select from among the specified work practices and
choose those most suitable for its operations.
    For both new and existing sources, the NESHAP is amended to require
that one or more of the control measures identified in the rule be used
to minimize fugitive dust emissions from open clinker storage piles.
The work practices would apply to open clinker storage piles regardless
of the quantity of clinker or the length of time that the clinker pile
is in existence.
    In addition, the owner or operator must include as part of their
operations and maintenance plan (required in Sec.  63.1347) the
location of their open clinker storage piles and the fugitive dust
control measures as specified in this rule that will be implemented to
control fugitive dust emissions from open clinker piles. We agree with
comments received that the list of allowed work practices reflects all
of the available practices documented in cement kiln facility operating
permits to control clinker storage pile fugitive emissions. The size,
type and duration of a clinker pile may warrant different types of work
practices. The final rule requires that one or more of a variety of
work practices need to be employed, recognizing that the source will
use the work practices that will be effective for the particular piles.
Thus, the EPA has revised the list of work practices to be consistent
with those listed in the proposal preamble. These are: Use of partial
enclosures, using a water spray or fogging system, applying appropriate
dust suppression agents, using a wind barrier and using a tarp.
Commenters also requested that the EPA allow other work practices if
approved by the delegated authority. Our regulations already provide
procedures for sources to seek approval of alternative work practices.
See section 112(h)(3) as implemented by 40 CFR 63.8(f).
    Several industry commenters stated that the definition of clinker
pile is problematic as proposed because it was not limited by size or
duration. Commenters note that it is not uncommon for small amounts of
clinker to be dropped, or to fall off a front-loader onto the ground
when being moved from a kiln to a storage location or from such a
location to the grinding mill. Because these are small amounts of
clinker, it is also not uncommon that these small quantities of clinker
will remain where they were dropped and may not be picked up or removed
until the necessary manpower becomes available; in some cases this
could be multiple days. Another industry commenter noted that because
of the short-term duration of temporary clinker stockpiles, the use of
work practices similar to those proposed for clinker storage piles is
not feasible. The industry trade association suggested the following
definition: ``Open clinker storage pile means an outdoor, unenclosed
accumulation of clinker on the ground, which contains in excess of
50,000 tons of clinker, and is utilized for a continuous period in
excess of 180 days.'' Under this suggested approach, only a clinker
storage pile meeting this definition would be subject to the work
practice standards.
    We are not adopting this approach. We believe that the potential to
emit may be different at different sites for a variety of reasons such
as weather and traffic conditions. Nor did the commenter provide
information indicating that open clinker storage piles of less than
50,000 tons or stored for less than 180 days are unlikely to produce
fugitive emissions. Indeed, as a result of weather, traffic or other
conditions, smaller piles stored for shorter periods have the evident
potential to emit substantial levels of fugitive emissions. Nor is any
such uniformly applicable distinction based on duration evident.
Clinker piles can be temporary but be replaced by a new pile at the
same (or nearby) location a few days later, with no essential
difference in fugitive emissions.
    Nonetheless, we believe that the commenter is correct that spills
are unavoidable, and that work practices designed for non-temporary
piles cannot feasibly be applied in such circumstances. The commenter
is also correct that work practices used for non-temporary piles would
be misapplied to temporary piles attributable to cleaning storage
structures. For these reasons, the definition of ``open storage pile''
excludes these types of piles. Specifically, the definition of open
clinker storage pile does not include temporary piles of clinker that
are the result of accidental spillage or temporary use of outdoor
storage while clinker storage buildings are being cleaned. This final
rule defines ``temporary'' to mean piles that remain in place for 3
days or less from their generation (3 days accommodating weekend
scheduling). This is sufficient time to either pick these spills up
(the applicable work practice for these spills) or to cover them to
prevent fugitive emissions.
    These final amendments will result in a cost savings to the
industry as compared to the 2010 rule. As a result of requiring work
practices instead of enclosures, we estimate that there will be a
savings of $8.25 million annually. See Final Portland Cement
Reconsideration Technical Support Document, December 20, 2012, in this
rulemaking docket.

D. September 9, 2015, Compliance Date for the Amended Existing Source
Standards

    The EPA proposed to establish September 9, 2015, as the compliance
date for the amended existing source NESHAP standards. The basic reason
for the proposed compliance date was that the proposed change in the PM
standard made possible different compliance alternatives for all of the
stack emission standards, and that it could legitimately take two years
from the original compliance date to implement these new compliance
strategies. See 77 FR 42385-87. Further, the amended compliance date
would apply to all of the stack emission standards due to the
interrelatedness of the standards: the mercury, THC and HCl standards
all typically involve some element of PM generation and capture and so
the controls must be integrated with PM control strategies. Id. at
42386.
    The record for this final rule supports the need for the September
9, 2015 compliance date. With respect to PM control, as the EPA
explained at proposal, plants now have the option of retaining
electrostatic precipitators (ESP) with modification or downstream
polishing baghouses, rather than replacing ESP with baghouses. Plants
may also size baghouses differently (with or without incorporation of
upstream or downstream polishing elements). The various types of
sorbent injection strategies to control organics, mercury and HCl, are
affected by the PM limits (and vice versa). Based on the facts of this
record for this source

category, the type, size and aggressiveness of the controls for these
HAP, as well as the PM controls, are not only interdependent but can
all change as a result of the amended PM standard. In addition, the
amended alternative oHAP standard affords additional compliance