Document ID: EPA-HQ-OAR-2012-0522-0064
Agency: epa
Document Type: Rule
Title: Phosphoric Acid Manufacturing and Phosphate Fertilizer Production RTR and Standards of Performance for Phosphate Processing
Posted Date: 2015-08-19T04:00Z

[Federal Register Volume 80, Number 160 (Wednesday, August 19, 2015)]
[Rules and Regulations]
[Pages 50385-50460]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-19732]

[[Page 50385]]

Vol. 80

Wednesday,

No. 160

August 19, 2015

Part II

Environmental Protection Agency

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40 CFR Parts 60 and 63

Phosphoric Acid Manufacturing and Phosphate Fertilizer Production RTR 
and Standards of Performance for Phosphate Processing; Final Rule

  Federal Register / Vol. 80 , No. 160 / Wednesday, August 19, 2015 / 
Rules and Regulations  

[[Page 50386]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[EPA-HQ-OAR-2012-0522; FRL-9931-01-OAR]
RIN 2060-AQ20

Phosphoric Acid Manufacturing and Phosphate Fertilizer Production 
RTR and Standards of Performance for Phosphate Processing

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action finalizes the residual risk and technology review 
conducted for the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production source categories regulated under national 
emission standards for hazardous air pollutants (NESHAP). In addition, 
this action finalizes an 8-year review of the current new source 
performance standards (NSPS) for five source categories. We are also 
taking final action addressing Clean Air Act (CAA) provisions related 
to emission standards for hazardous air pollutants, review and revision 
of emission standards, and work practice standards. The final 
amendments to the Phosphoric Acid Manufacturing NESHAP include: Numeric 
emission limits for previously unregulated mercury (Hg) and total 
fluoride emissions from calciners; work practice standards for hydrogen 
fluoride (HF) emissions from previously unregulated gypsum dewatering 
stacks and cooling ponds; clarifications to the applicability and 
monitoring requirements to accommodate process equipment and technology 
changes; removal of the exemptions for startup, shutdown, and 
malfunction (SSM); adoption of work practice standards for periods of 
startup and shutdown; and revised recordkeeping and reporting 
requirements for periods of SSM. The final amendments to the Phosphate 
Fertilizer Production NESHAP include: Clarifications to the 
applicability and monitoring requirements to accommodate process 
equipment and technology changes; removal of the exemptions for SSM; 
adoption of work practice standards for periods of startup and 
shutdown; and revised recordkeeping and reporting requirements for 
periods of SSM. The revised NESHAP for Phosphoric Acid Manufacturing 
facilities will mitigate future increases of Hg emissions from 
phosphate rock calciners by requiring pollution prevention measures. 
Further, based on the 8-year review of the current NSPS for these 
source categories, the EPA determined that no revisions to the numeric 
emission limits in those rules are warranted.

DATES: This final action is effective on August 19, 2015. The 
incorporation by reference of certain publications listed in the rule 
is approved by the Director of the Federal Register as of August 19, 
2015.

ADDRESSES: The Environmental Protection Agency (EPA) has established a 
docket for this action under Docket ID No. EPA-HQ-OAR-2012-0522. All 
documents in the docket are listed on the www.regulations.gov Web site. 
Although listed in the index, some information is not publicly 
available, e.g., confidential business information (CBI) or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the Internet 
and will be publicly available only in hard copy form. Publicly 
available docket materials are available either electronically through 
http://www.regulations.gov, or in hard copy at the EPA Docket Center, 
EPA WJC West Building, Room Number 3334, 1301 Constitution Ave. NW., 
Washington, DC. The Public Reading Room hours of operation are 8:30 
a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through Friday. 
The telephone number for the Public Reading Room is (202) 566-1744, and 
the telephone number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For questions about this final action, 
contact Dr. Tina Ndoh, Sector Policies and Programs Division (D243-02), 
Office of Air Quality Planning and Standards, U.S. Environmental 
Protection Agency, Research Triangle Park, North Carolina, 27711; 
telephone number: (919) 541-2750; fax number: (919) 541-5450; and email 
address: Ndoh.Tina@epa.gov. For specific information regarding the risk 
modeling methodology, contact James Hirtz, Health and Environmental 
Impacts Division (C539-02), Office of Air Quality Planning and 
Standards, U.S. Environmental Protection Agency, Research Triangle 
Park, North Carolina 27711; telephone number: (919) 541-0881; fax 
number: (919) 541-0359; and email address: Hirtz.James@epa.gov. For 
information about the applicability of the NESHAP or NSPS to a 
particular entity, contact Scott Throwe, Office of Enforcement and 
Compliance Assurance, U.S. Environmental Protection Agency, EPA WJC, 
1200 Pennsylvania Ave. NW., Washington, DC 20460; telephone number: 
(202) 562-7013; and email address: Throwe.Scott@epa.gov.

SUPPLEMENTARY INFORMATION: Preamble Acronyms and Abbreviations. We use 
multiple acronyms and terms in this preamble. While this list may not 
be exhaustive, to ease the reading of this preamble and for reference 
purposes, the EPA defines the following terms and acronyms here:

ACI Activated carbon injection
AEGL Acute exposure guideline levels
AFPC Association of Fertilizer and Phosphate Chemists
AOAC Association of Official Analytical Chemists
BACT Best available control technology
BSER Best System of Emissions Reduction
BTF Beyond the floor
CAA Clean Air Act
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS Continuous emissions monitoring system
CFR Code of Federal Regulations
CMS Continuous monitoring system
CPMS Continuous parameter monitoring system
DAP Diammonium phosphate
DOE Department of Energy
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
FR Federal Register
FTIR Fourier transform infrared spectroscopy
GMCS Gore Mercury Control System
GTSP Granular triple superphosphate
HAP Hazardous air pollutants
HF Hydrogen fluoride
Hg Mercury
HI Hazard index
HQ Hazard quotient
ICR Information Collection Request
LAER Lowest achievable emissions rate
lb/MMBtu Pounds per million Btu
LOAEL Lowest-observed-adverse-effect level
MACT Maximum achievable control technology
MAP Monoammonium phosphate
mg/dscm Milligrams per dry standard cubic meter
MIBK Methyl isobutyl ketone
MIR Maximum individual risk
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NAS National Academy of Sciences
NESHAP National Emissions Standards for Hazardous Air Pollutants
NETL National Energy Technology Laboratory
NOAEL No-observed-adverse-effect level
NSPS New source performance standard
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
P2O5 Phosphorus pentoxide
PAC Powdered activated carbon

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PB-HAP Hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PM Particulate matter
POM Polycyclic organic matter
PPA Purified phosphoric acid
ppm Parts per million
RACT Reasonably available control technology
RBLC RACT/BACT/LAER Clearinghouse
REL Reference exposure level
RFA Regulatory Flexibility Act
RTR Residual risk and technology review
SBA Small Business Administration
SiF4 Silicon tetrafluoride
SPA Superphosphoric acid
SSM Startup, shutdown, and malfunction
TOSHI Target organ-specific hazard index
tpy Tons per year
TRIM Total Risk Integrated Modeling System
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
TSP Triple superphosphates
TTN Technology Transfer Network
UMRA Unfunded Mandates Reform Act
UPL Upper prediction limit
VCS Voluntary consensus standards
WESP Wet electrostatic precipitator
WPPA Wet-process phosphoric acid
WWW World Wide Web

    Background Information. On November 7, 2014 (79 FR 66511), the EPA 
proposed revisions to the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production national emission standards for hazardous air 
pollutants (NESHAP) in conjunction with the residual risk and 
technology review (RTR) for those NESHAP, 40 CFR part 63, subparts AA 
and BB, and required 8-year review of the Standards of Performance for 
the Phosphate Fertilizer Industry new source performance standards 
(NSPS) for 40 CFR part 60, subparts T, U, V, W and X. In this action, 
we are finalizing decisions and revisions for the rules. We summarize 
some of the more significant comments we received regarding the 
proposed rule and provide our responses in this preamble. A summary of 
all other public comments on the proposal and the EPA's responses to 
those comments is available in ``Phosphoric Acid Manufacturing and 
Phosphate Fertilizer Production RTR and Standards of Performance for 
Phosphate Processing--Summary of Public Comments and Responses'' which 
is available in Docket ID No. EPA-HQ-OAR-2012-0522. A ``track changes'' 
version of the regulatory language that incorporates the changes in 
this action for each NSPS is available in the docket. The NESHAP were 
replaced in their entirety to assist in readability of the language and 
to ensure that citations were accurate.
    Organization of this Document. The information in this preamble is 
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
    C. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the statutory authority for this action?
    B. What are the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production source categories and how do the NESHAP and 
NSPS regulate emissions from these source categories?
    C. What changes did we propose for the Phosphoric Acid 
Manufacturing and Phosphate Fertilizer Production source categories 
in our November 7, 2014 proposal?
III. What is included in this final rule for the Phosphoric Acid 
Manufacturing source category?
    A. What are the final rule amendments based on the NESHAP 
residual risk review for the Phosphoric Acid Manufacturing source 
category?
    B. What are the final rule amendments based on the NESHAP 
technology review for the Phosphoric Acid Manufacturing source 
category?
    C. What are the final rule amendments pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(h) for the Phosphoric Acid 
Manufacturing source category?
    D. What are the final rule amendments based on the NSPS review 
for the Phosphoric Acid Manufacturing source category?
    E. What are the final rule amendments addressing emissions 
during periods of startup, shutdown, and malfunction for the 
Phosphoric Acid Manufacturing source category?
    F. What other changes are we making to the NESHAP and NSPS for 
the Phosphoric Acid Manufacturing source category?
    G. What are the effective and compliance dates of the standards 
for the Phosphoric Acid Manufacturing source category?
    H. What are the requirements for submission of performance test 
data to the EPA for the Phosphoric Acid Manufacturing source 
category?
IV. What is included in this final rule for the Phosphate Fertilizer 
Production source category?
    A. What are the final rule amendments based on the NESHAP risk 
review for the Phosphate Fertilizer Production source category?
    B. What are the final rule amendments based on the NESHAP 
technology review for the Phosphate Fertilizer Production source 
category?
    C. What are the final rule amendments based on the NSPS review 
for the Phosphate Fertilizer Production source category?
    D. What are the final rule amendments addressing emissions 
during periods of startup, shutdown, and malfunction for the 
Phosphate Fertilizer Production source category?
    E. What other changes are we making to the NESHAP and NSPS for 
the Phosphate Fertilizer Production source category?
    F. What are the effective and compliance dates of the standards 
for the Phosphate Fertilizer Production source category?
    G. What are the requirements for submission of performance test 
data to the EPA for the Phosphate Fertilizer Production source 
category?
V. What is the rationale for our final decisions and amendments for 
the Phosphoric Acid Manufacturing source category?
    A. Residual Risk Review for the Phosphoric Acid Manufacturing 
Source Category
    B. Technology Review for the Phosphoric Acid Manufacturing 
Source Category
    C. CAA Sections 112(d)(2), 112(d)(3), and 112(h) for the 
Phosphoric Acid Manufacturing Source Category
    D. NSPS Review for the Phosphoric Acid Manufacturing Source 
Category
    E. Startup, Shutdown, and Malfunction Provisions for the 
Phosphoric Acid Manufacturing Source Category
    F. Other Changes Made to the Phosphoric Acid Manufacturing 
NESHAP and NSPS
VI. What is the rationale for our final decisions and amendments for 
the Phosphate Fertilizer Production source category?
    A. Residual Risk Review for the Phosphate Fertilizer Production 
Source Category
    B. Technology Review for the Phosphate Fertilizer Production 
Source Category
    C. NSPS Review for the Phosphate Fertilizer Production Source 
Category
    D. Startup, Shutdown, and Malfunction Provisions for the 
Phosphate Fertilizer Production Source Category
    E. Other Changes Made to the Phosphate Fertilizer Production 
NESHAP and NSPS
VII. Summary of Cost, Environmental, and Economic Impacts and 
Additional Analyses Conducted
    A. What are the affected facilities?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
    F. What analysis of environmental justice did we conduct?
    G. What analysis of children's environmental health did we 
conduct?
VIII. Statutory and Executive Order Reviews
    A. Executive Orders 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    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

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Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    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. Does this action apply to me?

    Regulated Entities. Categories and entities potentially regulated 
by this action are shown in Table 1 of this preamble.

 Table 1--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
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              NESHAP and source  category                 NAICS \a\ code
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Phosphoric Acid Manufacturing Phosphate Fertilizer               325312
 Production............................................
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\a\ North American Industry Classification System.

    Table 1 of this preamble is not intended to be exhaustive, but 
rather to provide a guide for readers regarding entities likely to be 
affected by the final action for the source category listed. To 
determine whether your facility is affected, you should examine the 
applicability criteria in the appropriate NESHAP. If you have any 
questions regarding the applicability of any aspect of this NESHAP, 
please contact the appropriate person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section of this preamble.

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

    In addition to being available in the docket, an electronic copy of 
this final action will also be available on the Internet through the 
Technology Transfer Network (TTN) Web site, a forum for information and 
technology exchange in various areas of air pollution control. 
Following signature by the EPA Administrator, the EPA will post a copy 
of this final action at http://www.epa.gov/ttn/atw/phosph/phosphpg.html. Following publication in the Federal Register, the EPA 
will post the Federal Register version and key technical documents at 
this same Web site.
    Additional information is available on the RTR Web site at http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. This information includes an 
overview of the RTR program, links to project Web sites for the RTR 
source categories and detailed emissions and other data we used as 
inputs to the risk assessments.

C. Judicial Review and Administrative Reconsideration

    Under CAA section 307(b)(1), judicial review of this final action 
is available only by filing a petition for review in the United States 
(U.S.) Court of Appeals for the District of Columbia Circuit by October 
19, 2015. Under CAA section 307(b)(2), the requirements established by 
this 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 reconsider the rule ``[i]f the 
person raising an objection can demonstrate to the Administrator 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 should 
submit a Petition for Reconsideration to the Office of the 
Administrator, U.S. EPA, Room 3000, EPA WJC 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

A. What is the statutory authority for this action?

1. NESHAP Authority
    Section 112 of the CAA establishes a two-stage regulatory process 
to address emissions of hazardous air pollutants (HAP) from stationary 
sources. In the first stage, we must identify categories of sources 
emitting one or more of the HAP listed in CAA section 112(b) and then 
promulgate technology-based NESHAP for those sources. ``Major sources'' 
are those that emit, or have the potential to emit, any single HAP at a 
rate of 10 tons per year (tpy) or more, or 25 tpy or more of any 
combination of HAP. For major sources, these standards are commonly 
referred to as maximum achievable control technology (MACT) standards 
and must reflect the maximum degree of emission reductions of HAP 
achievable (after considering cost, energy requirements, and non-air 
quality health and environmental impacts). In developing MACT 
standards, CAA section 112(d)(2) directs the EPA to consider the 
application of measures, processes, methods, systems or techniques, 
including, but not limited to those that reduce the volume of or 
eliminate HAP emissions through process changes, substitution of 
materials, or other modifications; enclose systems or processes to 
eliminate emissions; collect, capture, or treat HAP when released from 
a process, stack, storage, or fugitive emissions point; are design, 
equipment, work practice, or operational standards; or any combination 
of the above.
    For these MACT standards, the statute specifies certain minimum 
stringency requirements, which are referred to as MACT floor 
requirements, and which may not be based on cost considerations. See 
CAA section 112(d)(3). For new sources, the MACT floor cannot be less 
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can 
be less stringent than floors for new sources, but they cannot be less 
stringent than the average emission limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing five sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, we must also consider control options that are more 
stringent than the floor, under CAA section 112(d)(2). 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.
    In the second stage of the regulatory process, the CAA requires the 
EPA to undertake two different analyses, which we refer to as the 
technology review and the residual risk review. Under the technology 
review, we must review the technology-based standards and revise them 
``as necessary (taking into account developments in practices, 
processes, and control technologies)'' no less frequently than every 8 
years, pursuant to CAA section 112(d)(6). Under the residual risk 
review, we must evaluate the risk to public health remaining after 
application of the technology-based

[[Page 50389]]

standards and revise the standards, if necessary, to provide an ample 
margin of safety to protect public health or to prevent, taking into 
consideration costs, energy, safety, and other relevant factors, an 
adverse environmental effect. The residual risk review is required 
within 8 years after promulgation of the technology-based standards, 
pursuant to CAA section 112(f). In conducting the residual risk review, 
if the EPA determines that the current standards provide an ample 
margin of safety to protect public health, it is not necessary to 
revise the MACT standards pursuant to CAA section 112(f).\1\ For more 
information on the statutory authority for this rule, see 79 FR 66512 
(November 7, 2014).
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    \1\ The U.S. Court of Appeals has affirmed this approach of 
implementing CAA section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 
1083 (D.C. Cir. 2008) (``If EPA determines that the existing 
technology-based standards provide an 'ample margin of safety,' then 
the Agency is free to readopt those standards during the residual 
risk rulemaking.'').
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2. NSPS Authority
    NSPS implement CAA section 111, which requires that each NSPS 
reflect the degree of emission limitation achievable through the 
application of the best system of emission reduction (BSER) which 
(taking into consideration the cost of achieving such emission 
reductions, any non-air quality health and environmental impact and 
energy requirements) the Administrator determines has been adequately 
demonstrated.
    Existing affected facilities that are modified or reconstructed are 
also subject to NSPS. Under CAA section 111(a)(4), ``modification'' 
means any physical change in, or change in the method of operation of, 
a stationary source which increases the amount of any air pollutant 
emitted by such source or which results in the emission of any air 
pollutant not previously emitted. Changes to an existing facility that 
do not result in an increase in emissions are not considered 
modifications.
    Rebuilt emission units would become subject to the NSPS under the 
reconstruction provisions in 40 CFR 60.15, regardless of changes in 
emission rate. Reconstruction means the replacement of components of an 
existing facility such that: (1) The fixed capital cost of the new 
components exceeds 50 percent of the fixed capital cost that would be 
required to construct a comparable entirely new facility; and (2) it is 
technologically and economically feasible to meet the applicable 
standards (40 CFR 60.15).
    Section 111(b)(1)(B) of the CAA requires the EPA to periodically 
review and, if appropriate, revise the standards of performance as 
necessary to reflect improvements in methods for reducing emissions. 
The EPA need not review an NSPS if the Agency determines that such 
review is not appropriate in light of readily available information on 
the efficacy of the standard. When conducting the review under CAA 
section 111(b)(1)(B), the EPA considers both: (1) Whether developments 
in technology or other factors support the conclusion that a different 
system of emissions reduction has become the BSER and (2) whether 
emissions limitations and percent reductions beyond those required by 
the current standards are achieved in practice.

B. What are the Phosphoric Acid Manufacturing and Phosphate Fertilizer 
Production source categories and how do the NESHAP and NSPS regulate 
emissions from these source categories?

1. Description of Phosphoric Acid Manufacturing Source Category
    In 2014, 12 facilities in the U.S. manufactured phosphoric acid. 
The basic step for producing phosphoric acid is acidulation of 
phosphate rock. Typically, sulfuric acid, phosphate rock, and water are 
combined together and allowed to react to produce phosphoric acid and 
gypsum. When phosphate rock is acidulated to manufacture wet-process 
phosphoric acid (WPPA), fluorine contained in the rock is released. 
Fluoride compounds, predominately HF, are produced as particulates and 
gases that are emitted to the atmosphere unless removed from the 
exhaust stream. Some of these same fluoride compounds also remain in 
the product acid and are released as air pollutants during subsequent 
processing of the acid. Gypsum is pumped as a slurry to ponds atop 
stacks of waste gypsum where the liquids separate from the slurry and 
are decanted for return to the process. The gypsum, which is discarded 
on the stack, is a solid waste stream produced in this process. Five 
facilities concentrate WPPA to make superphosphoric acid (SPA), 
typically using the vacuum evaporation process. While one manufacturer 
is permitted to use a submerged combustion process for the production 
of SPA, that process was indefinitely shutdown on June 1, 2006. The 
majority of WPPA is used to produce phosphate fertilizers.
    Additional processes may also be used to further refine phosphoric 
acid. At least two facilities have a defluorination process to remove 
fluorides from the phosphoric acid product, and one company uses a 
solvent extraction process to remove metals and organics and to further 
refine WPPA into purified phosphoric acid (PPA) for use in food 
manufacturing or specialized chemical processes. In addition, four 
facilities have oxidation processes to remove organics from the acid 
(i.e., the green acid process). One of these facilities also calcines 
the ore prior to the acidulation process to help achieve the desired 
organic content reduction for the final acid product.
    Sources of HF emissions from phosphoric acid plants include gypsum 
dewatering stacks, cooling ponds, cooling towers, calciners, reactors, 
filters, evaporators and other process equipment.
2. Federal Air Emission Standards Applicable to the Phosphoric Acid 
Manufacturing Source Category
    The following federal air emission standards are associated with 
the Phosphoric Acid Manufacturing source category and are the subject 
of this final action:

     National Emission Standards for Hazardous Air 
Pollutants from Phosphoric Acid Manufacturing Plants (40 CFR part 
63, subpart AA);
     Standards of Performance for the Phosphate Fertilizer 
Industry: Wet-Process Phosphoric Acid Plants (40 CFR part 60, 
subpart T); and
     Standards of Performance for the Phosphate Fertilizer 
Industry: Superphosphoric Acid Plants (40 CFR part 60, subpart U).

    a. Phosphoric Acid Manufacturing NESHAP Emission Regulations. The 
EPA promulgated 40 CFR part 63, subpart AA for the Phosphoric Acid 
Manufacturing source category on June 10, 1999 (64 FR 31358). The 
NESHAP established standards for major sources to control HAP emissions 
from phosphoric acid facilities. Total fluoride emission limits, as a 
surrogate for the HAP HF, were set for WPPA process lines and SPA 
process lines. The NESHAP established emission limits for particulate 
matter (PM) from phosphate rock dryers and phosphate rock calciners as 
a surrogate for metal HAP. Also, the NESHAP established an emission 
limit for methyl isobutyl ketone (MIBK) for PPA process lines and work 
practices for cooling towers. For more information on this NESHAP, see 
79 FR 66512.
    b. Phosphoric Acid Manufacturing NSPS Emission Regulations. The EPA 
promulgated 40 CFR part 60, subpart T for WPPA Plants on August 6, 1975 
(40 FR 33154). The NSPS established standards to control total fluoride 
emissions from WPPA plants, including

[[Page 50390]]

reactors, filters, evaporators, and hot wells.
    The EPA promulgated 40 CFR part 60, subpart U for SPA Plants on 
August 6, 1975 (40 FR 33155). The NSPS established standards to control 
total fluoride emissions from SPA plants, including evaporators, hot 
wells, acid sumps, and cooling tanks.
    For more information on these NSPS, see 79 FR 66512.
3. Description of Phosphate Fertilizer Production Source Category
    There are 11 operating facilities that produce phosphate 
fertilizers, and most facilities have the ability to produce either 
monoammonium phosphates (MAP) or diammonium phosphates (DAP) in the 
same process train. However, approximately 80 percent of all ammonium 
phosphates are produced as MAP. MAP and DAP plants are generally 
collocated with WPPA plants since both are manufactured from phosphoric 
acid and ammonia. The MAP and DAP manufacturing process consists of 
three basic steps: Reaction, granulation, and finishing operations such 
as drying, cooling, and screening. Sources of fluoride emissions from 
MAP and DAP plants include the reactor, granulator, dryer, cooler, 
screens, and mills. Some of the fluoride is liberated as HF and silicon 
tetrafluoride (SiF4), but the majority is emitted as HF.
    Triple superphosphates (TSP) are made as run-of-pile TSP (ROP-TSP) 
and granular TSP (GTSP) by reacting WPPA with ground phosphate rock. 
The phosphoric acid used in the GTSP process is appreciably lower in 
concentration (40-percent phosphorus pentoxide 
(P2O5)) than that used to manufacture ROP-TSP 
product (50 to 55-percent P2O5). The GTSP process 
yields larger, more uniform particles with improved storage and 
handling properties than the ROP-TSP process. Currently, no facilities 
produce ROP-TSP or GTSP,\2\ although one facility retains an operating 
permit to store GTSP.
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    \2\ According to 2014 production and trade statistics issued by 
International Fertilizer Industry Association (IFA).
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4. Federal Air Emission Standards Applicable to the Phosphate 
Fertilizer Production Source Category
    The following federal air emission standards are associated with 
the Phosphate Fertilizer Production source category and are subject of 
this final action:

     National Emission Standards for Hazardous Air 
Pollutants from Phosphate Fertilizers Production Plants (40 CFR part 
63, subpart BB);
     Standards of Performance for the Phosphate Fertilizer 
Industry: Diammonium Phosphate Plants (40 CFR part 60, subpart V);
     Standards of Performance for the Phosphate Fertilizer 
Industry: Triple Superphosphate Plants (40 CFR part 60, subpart W); 
and
     Standards of Performance for the Phosphate Fertilizer 
Industry: Granular Triple Superphosphate Storage Facilities (40 CFR 
part 60, subpart X).

    a. Phosphate Fertilizer Production NESHAP Emission Regulations. The 
EPA promulgated 40 CFR part 63, subpart BB for the Phosphate Fertilizer 
Production source category on June 10, 1999 (64 FR 31358). The NESHAP 
established standards for major sources to control HAP emissions from 
phosphate fertilizer facilities. As a surrogate for HF, the NESHAP set 
total fluoride emission limits for DAP and/or MAP process lines and 
GTSP process lines and storage buildings. The NESHAP also established 
work practices for GTSP production. For more information on this 
NESHAP, see 79 FR 66512.
    b. Phosphate Fertilizer Production NSPS Emission Regulations. The 
EPA promulgated 40 CFR part 60, subpart V for Diammonium Phosphate 
Plants on July 25, 1977 (42 FR 37938). The NSPS established standards 
to control total fluoride emissions from granular DAP plants, including 
reactors, granulators, dryers, coolers, screens, and mills.
    The EPA promulgated 40 CFR part 60, subpart W for TSP plants on 
July 25, 1977 (42 FR 37938). The NSPS established standards to control 
total fluoride emissions from the production of ROP-TSP and GTSP, and 
the storage of ROP-TSP.
    The EPA promulgated 40 CFR part 60, subpart X for GTSP storage 
facilities on July 25, 1977 (42 FR 37938). The NSPS established 
standards to control total fluoride emissions from the storage of GTSP, 
including storage or curing buildings (noted as ``piles'' in subpart 
X), conveyors, elevators, screens, and mills.
    For more information on these NSPS, see 79 FR 66512.

C. What changes did we propose for the Phosphoric Acid Manufacturing 
and Phosphate Fertilizer Production source categories in our November 
7, 2014 proposal?

    On November 7, 2014 (79 FR 66512), the EPA published a proposed 
rule in the Federal Register for both the Phosphoric Acid Manufacturing 
NESHAP, 40 CFR part 63, subpart AA, and Phosphate Fertilizer Production 
NESHAP, 40 CFR part 63, subpart BB that took into consideration the RTR 
analyses. We also proposed other revisions to these NESHAP. In the 
proposed rule, we proposed:
    For Phosphoric Acid Manufacturers:

     Numeric emission limits for Hg and work practice 
standards for HF from calciners; and
     Work practice standards for HF emissions from gypsum 
dewatering stacks and cooling ponds.

    For both Phosphoric Acid Manufacturers and Phosphate Fertilizer 
Producers:

     Emission limits regulating HF emissions as the target 
HAP (HF), instead of the long-standing surrogate for HF, total F;
     Clarifications to applicability and certain 
definitions;
     Revisions to requirements related to emissions during 
periods of SSM;
     Revisions to monitoring requirements for absorbers;
     Requirements for reporting of performance testing 
through the electronic reporting tool (ERT);
     Modification to the format to reference tables for 
emissions limits and monitoring requirements; and
     Several minor clarifications and corrections.

    In addition, we proposed revisions to the NSPS subparts T, U, V, W, 
and X, including clarifications to applicability and certain 
definitions, and revisions to monitoring and recordkeeping requirements 
for absorbers.

III. What is included in this final rule for the Phosphoric Acid 
Manufacturing source category?

    This action finalizes the EPA's determinations pursuant to the RTR 
provisions of CAA section 112 and the 8-year review provisions of CAA 
section 111 for the Phosphoric Acid Manufacturing source category. 
Today's action also finalizes several of the proposed changes to the 
NESHAP subpart AA and the NSPS subparts T and U that are described in 
section II.C. of this preamble. This action also finalizes other 
changes to the NESHAP subpart AA in consideration of comments on issues 
raised in the proposed rulemaking, as described in section V of this 
preamble.

A. What are the final rule amendments based on the NESHAP residual risk 
review for the Phosphoric Acid Manufacturing source category?

    The residual risk review for the Phosphoric Acid Manufacturing 
source category did not change since proposal; we found that the 
current standards provide an ample margin of safety to protect public 
health (79 FR 66512) and prevent an adverse environmental effect. We 
are, therefore, not tightening the standards under section 112(f)(2)

[[Page 50391]]

(for NESHAP subpart AA) based on the residual risk review, and are thus 
readopting the existing standards under section 112(f)(2). See sections 
V.A.3 and V.A.4 of this preamble for discussion on key comments and 
responses regarding the residual risk review.

B. What are the final rule amendments based on the NESHAP technology 
review for the Phosphoric Acid Manufacturing source category?

    The technology review for the Phosphoric Acid Manufacturing source 
category did not change since proposal (79 FR 66512). We determined 
that there are no cost-effective developments in practices, processes, 
and control technologies that warrant revisions to the MACT standards 
for this source category (79 FR 66512). Therefore, we are not amending 
the MACT standards under CAA section 112(d)(6). See sections V.B.3 and 
V.B.4 of this preamble for discussion on key comments and responses 
regarding the technology review.

C. What are the final rule amendments pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(h) for the Phosphoric Acid Manufacturing 
source category?

    We are finalizing MACT standards for HF and Hg pursuant to CAA 
sections 112(d)(2) and 112(d)(3) for phosphate rock calciners, an 
emissions source that was initially regulated for HAP metals using PM 
as a surrogate. Specifically, we are finalizing, as proposed, the 
elimination of the use of PM as a surrogate for Hg; however, we are 
making changes to the proposed Hg emission limit for phosphate rock 
calciners in NESHAP subpart AA to reflect MACT floor level emission 
standards for existing sources. We are finalizing the proposed beyond-
the-floor (BTF) emission standard for Hg emissions from new phosphate 
rock calciners. We discuss the changes to the Hg emission limit in 
section V.C.3.a.i of this preamble. In addition, we are finalizing, as 
proposed, to retain the PM standard as a surrogate for other HAP metal 
emissions from phosphate rock calciners. However, in consideration of 
comments received during the public comment period for the proposed 
rulemaking, we are not finalizing work practice standards for HF from 
phosphate rock calciners, as proposed. Instead, as discussed in section 
V.C.3.a.ii of this preamble, we are including a total fluoride emission 
limit for phosphate rock calciners in NESHAP subpart AA.
    Also, in consideration of comments received (see section V.C.3.b.i 
of this preamble for details), we are not adopting the proposed work 
practice in NESHAP subpart AA that would limit the size of active 
gypsum dewatering stacks (which would have been applicable to 
facilities when new gypsum dewatering stacks are constructed). Lastly, 
we are finalizing work practice standards pursuant to CAA section 
112(h) for gypsum dewatering stacks and cooling ponds--emissions 
sources that were not regulated under the initial MACT standard. 
Specifically, we are finalizing in NESHAP subpart AA, as proposed, the 
work practice standard that requires owners or operators to prepare and 
operate in accordance with a gypsum dewatering stack and cooling pond 
management plan. However, based on analysis of public comments, we are 
making several changes to the specific control techniques that we 
proposed as options in the plan for controlling fugitive HF emissions 
(see section V.C.3.b.ii of this preamble for details on these changes). 
In the final rule, the Agency is using the terminology ``control 
measures'' in lieu of the proposed terminology ``control techniques'' 
because we feel this more accurately describes the list of options in 
the rule and avoids confusion with other CAA programs.

D. What are the final rule amendments based on the NSPS review for the 
Phosphoric Acid Manufacturing source category?

    We are finalizing our determination that revisions to NSPS subpart 
T and subpart U standards are not appropriate pursuant to CAA section 
111(b)(1)(B). All Phosphoric Acid Manufacturing NSPS (under subpart T 
and subpart U) emission sources, and the control technologies that 
would be employed, are the same as those for the NESHAP regulating 
phosphoric acid plants, such that we reached the same determination 
that there are no identified cost-effective practices or technologies 
that would provide additional emission reductions. Additionally, there 
were no identified technologies that have been adequately demonstrated 
to achieve in practice emission controls that would result in more 
stringent total fluoride limits for these NSPS. See section V.D of this 
preamble for discussion on key comments and responses regarding the 
NSPS review.

E. What are the final rule amendments addressing emissions during 
periods of startup, shutdown, and malfunction for the Phosphoric Acid 
Manufacturing source category?

    We are finalizing, as proposed, changes to the Phosphoric Acid 
Manufacturing NESHAP, subpart AA to eliminate the SSM exemption. 
Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008), the 
EPA has established standards in this rule that apply at all times. 
Appendix A of subpart AA (the General Provisions Applicability Table) 
is being revised to change several references related to requirements 
that apply during periods of SSM. We also eliminated or revised certain 
recordkeeping and reporting requirements related to the eliminated SSM 
exemption. The EPA also made changes to the rule to remove or modify 
inappropriate, unnecessary, or redundant language in the absence of the 
SSM exemption. For this source category, we determined that work 
practice standards for periods of startup and shutdown are appropriate 
in lieu of numeric emission limits due to the short duration of startup 
and shutdown, and control devices used on the various process lines in 
this source category are effective at achieving desired emission 
reductions immediately upon startup (79 FR 66541). Therefore, we are 
finalizing in NESHAP subpart AA the proposed work practice standards 
for periods of startup and shutdown. However, in consideration of 
comments received during the public comment period, we are making 
changes to the work practice standards in order to clarify that the 
standard applies in lieu of numeric emission limits and how compliance 
with the standard is demonstrated. In order to comply with the work 
practice standard, facilities must monitor the same control device 
operating parameters and comply with the same operating limits that are 
established to otherwise comply with the emission limits. Additionally, 
we added a definition of ``startup'' and ``shutdown'' in the 
definitions section of the final rule to specify when startup begins 
and ends, and when shutdown begins and ends. See section V.E.3 of this 
preamble for details on these changes.

F. What other changes are we making to the NESHAP and NSPS for the 
Phosphoric Acid Manufacturing source category?

    Today's rule also finalizes, as proposed, revisions to several 
other Phosphoric Acid Manufacturing NESHAP and NSPS requirements. We 
are finalizing, as proposed, several miscellaneous changes to clarify 
applicability and certain definitions, as follows:

     Adopting the proposed SPA process line definition in 
NESHAP subpart AA to include oxidation reactors;

[[Page 50392]]

     Adopting the proposed SPA plant definition in NSPS 
subpart U to include oxidation reactors;
     Finalizing the proposed revisions to rename ``gypsum 
stack'' to ``gypsum dewatering stack'' in NESHAP subpart AA; and
     Finalizing the proposed definitions for ``cooling 
pond'' and ``raffinate stream'' in NESHAP subpart AA.

    We are finalizing, as proposed, several changes to testing, 
monitoring, recordkeeping and reporting requirements to provide 
consistency, clarification and flexibility, as follows:

     Finalizing the proposed revisions to NESHAP subpart AA 
that require a minimum pressure drop of 5 inches of water column for 
facilities that use pressure differential in parametric monitoring;
     Finalizing the proposal to remove the requirement in 
NESHAP subpart AA that facilities must request and obtain approval 
of the Administrator for changing operating limits;
     Adopting the proposed addition of a site-specific 
monitoring plan and calibration requirements for a continuous 
monitoring system (CMS) in NESHAP subpart AA;
     Adopting the proposed term ``absorber'' in lieu of 
``scrubber'' in NESHAP subpart AA;
     Adopting the proposed format of NESHAP subpart AA to 
reference tables for emissions limits and monitoring requirements;
     Adopting the proposed provisions in NSPS subpart T and 
NSPS subpart U that require the owner or operator to establish an 
allowable range for the pressure drop through the process scrubbing 
system, keep records of the daily average pressure drop through the 
process scrubbing system, and keep records of deviations; and
     Adopting the proposed term ``absorber'' in lieu of 
``process scrubbing system'' in NSPS subpart T and NSPS subpart U.

    We are also finalizing changes to the NESHAP and NSPS for the 
Phosphoric Acid Manufacturing source category on issues raised in 
response to the proposed rulemaking, as follows (refer to section V.F.2 
of this preamble for further details):

     Revising the definition of oxidation reactor in the 
final rule for NESHAP subpart AA and NSPS subpart U;
     Finalizing liquid-to-gas ratio monitoring in NESHAP 
subpart AA for low-energy absorbers (i.e., absorbers that are 
designed to operate with pressure drops of 5 inches of water column 
or less) in lieu of monitoring influent liquid flow and pressure 
drop through the absorber;
     Clarifying in NESHAP subpart AA that during the most 
recent performance test, if owners or operators demonstrate 
compliance with the emission limit while operating their control 
device outside the previously established operating limit, owners or 
operators must establish a new operating limit based on that most 
recent performance test and notify the Administrator that the 
operating limit changed based on data collected during the most 
recent performance test; and
     Clarifying in NESHAP subpart AA that facilities not be 
required to obtain approval, and, instead, immediately comply with a 
new operating limit when it is developed and submitted to the 
Administrator.

G. What are the effective and compliance dates of the standards for the 
Phosphoric Acid Manufacturing source category?

    The revisions to the NSPS and NESHAP standards we promulgate in 
this action for the Phosphoric Acid Manufacturing source category are 
effective on August 19, 2015.
    The compliance date for the Hg limit in NESHAP subpart AA for 
existing phosphate rock calciners is August 19, 2015. Based on the data 
that the EPA has received, all existing phosphate rock calciners are 
meeting the Hg limit; therefore, no additional time would be required 
to achieve compliance with this standard.
    The compliance date for the Hg limit in NESHAP subpart AA for new 
phosphate rock calciners is August 19, 2015, or upon startup, whichever 
is later. We are not aware of any new phosphate rock calciners 
operating today. New phosphate rock calciners that commence 
construction or reconstruction after the effective date of this rule 
would be required to comply with the Hg limits immediately upon 
startup.
    The compliance date for the total fluoride limits in NESHAP subpart 
AA for all (existing and new) phosphate rock calciners is August 19, 
2015, or upon startup, whichever is later. Based on the data that the 
EPA has received, all phosphate rock calciners are meeting the total 
fluoride limit; therefore, no additional time would be required to 
achieve compliance with this standard.
    The compliance date in NESHAP subpart AA for preparing and 
operating in accordance with a gypsum dewatering stack and cooling pond 
management plan is August 19, 2016. A 1-year compliance lead-time will 
provide facilities adequate time to prepare and submit their plan for 
approval to the Administrator.
    The compliance date for when facilities must include oxidation 
reactors in determining compliance with the total fluoride limit in 
NESHAP subpart AA for SPA process lines is August 19, 2016. We believe 
that 1 year is necessary because a facility may need to install 
additional control technology. A 1-year compliance period will provide 
the facility adequate time to design and install controls.
    The compliance date in NESHAP subpart AA for when to install, 
calibrate, and maintain a bag leak detection system on a fabric filter 
is August 19, 2016. We believe that 1 year is necessary because some 
facilities that currently operate a fabric filter do not have a bag 
leak detection system and will need time to purchase and install this 
compliance monitoring equipment and implement quality assurance 
measures.
    The compliance date in NESHAP subpart AA for the revised startup 
and shutdown requirements is August 19, 2015. We determined that the 
feasibility of operating the control devices used to control HAP 
emissions from phosphoric acid manufacturing is not limited by specific 
process operating conditions.
    Finally, to ensure continuous compliance with the standard, the 
compliance date for the monitoring and recordkeeping requirements in 
NSPS subparts T and U for all new WPPA plants and SPA plants is August 
19, 2015, or upon startup, whichever is later.

H. What are the requirements for submission of performance test data to 
the EPA for the Phosphoric Acid Manufacturing source category?

    As stated in the preamble to the proposed rule, the EPA is taking a 
step to increase the ease and efficiency of data submittal and data 
accessibility. Specifically, the EPA is requiring owners and operators 
of phosphoric acid facilities to submit electronic copies of certain 
required performance test reports.
    As mentioned in the preamble of the proposal, data will be 
collected by direct computer-to-computer electronic transfer using EPA-
provided software. As discussed in the proposal, the EPA-provided 
software is an electronic performance test report tool called the ERT. 
The ERT will generate an electronic report package which will be 
submitted to the Compliance and Emissions Data Reporting Interface 
(CEDRI) and then archived to the EPA's Central Data Exchange (CDX). A 
description and instructions for use of the ERT can be found at http://www.epa.gov/ttn/chief/ert/index.html, and CEDRI can be accessed through 
the CDX Web site at www.epa.gov/cdx.
    The requirement to submit performance test data electronically to 
the EPA does not create any additional performance testing and will 
apply only to those performance tests conducted using test methods that 
are supported by the ERT. A listing of the pollutants and test methods 
supported by the ERT is available at the ERT Web site. The EPA 
believes, through this approach, industry will save time in the

[[Page 50393]]

performance test submittal process. Additionally, this rulemaking 
benefits industry by cutting back on recordkeeping costs as the 
performance test reports that are submitted to the EPA using CEDRI are 
no longer required to be kept in hard copy.
    As mentioned in the proposed preamble, state, local, and tribal 
agencies will benefit from more streamlined and accurate review of 
performance test data that will be available on the EPA WebFIRE 
database. The public will also benefit. Having these data publicly 
available enhances transparency and accountability. For a more thorough 
discussion of electronic reporting of performance tests using direct 
computer-to-computer electronic transfer and using EPA-provided 
software, see the discussion in the preamble of the proposal.
    In summary, in addition to supporting regulation development, 
control strategy development, and other air pollution control 
activities, having an electronic database populated with performance 
test data will save industry, state, local, and tribal agencies, and 
the EPA significant time, money, and effort, while improving the 
quality of emission inventories, air quality regulations, and enhancing 
the public's access to this important information.

IV. What is included in this final rule for the Phosphate Fertilizer 
Production source category?

    This action finalizes the EPA's determinations pursuant to the RTR 
provisions of CAA section 112 and the 8-year review provisions of CAA 
section 111 for the Phosphate Fertilizer Production source category. 
Today's action also finalizes several of the proposed changes to the 
NESHAP subpart BB and the NSPS subparts V, W, and X that are described 
in section II.C of this preamble. This action also finalizes other 
changes to the NESHAP subpart BB in consideration of comments on issues 
raised in the proposed rulemaking, as described in section VI of this 
preamble.

A. What are the final rule amendments based on the NESHAP risk review 
for the Phosphate Fertilizer Production source category?

    The residual risk review for the Phosphate Fertilizer Production 
source category did not change since proposal; we found that the 
current standards provide an ample margin of safety to protect public 
health (79 FR 66512) and prevent an adverse environmental effect. We 
are, therefore, not tightening the standards under section 112(f)(2) 
(for NESHAP subpart BB) based on the residual risk review, and are thus 
readopting the existing standards under section 112(f)(2).

B. What are the final rule amendments based on the NESHAP technology 
review for the Phosphate Fertilizer Production source category?

    The technology review for the Phosphate Fertilizer Production 
source category did not change since proposal (79 FR 66512). We 
determined that there are no cost-effective developments in practices, 
processes, and control technologies that warrant revisions to the MACT 
standards for this source category (79 FR 66512). Therefore, we are not 
amending the MACT standards under CAA section 112(d)(6).

C. What are the final rule amendments based on the NSPS review for the 
Phosphate Fertilizer Production source category?

    We are finalizing our determination that revisions to NSPS subpart 
V, subpart W, and subpart X standards are not appropriate pursuant to 
CAA section 111(b)(1)(B). All Phosphate Fertilizer Production NSPS 
(under subpart V, subpart W, and subpart X) emission sources, and the 
control technologies that would be employed, are the same as those for 
the NESHAP regulating phosphate fertilizer plants, such that we reached 
the same determination that there are no identified cost-effective 
practices or technologies that would provide additional emission 
reductions. Additionally, there were no identified technologies that 
have been adequately demonstrated to achieve in practice emission 
controls that would result in more stringent total fluoride limits for 
these NSPS.

D. What are the final rule amendments addressing emissions during 
periods of startup, shutdown, and malfunction for the Phosphate 
Fertilizer Production source category?

    We are finalizing, as proposed, changes to the Phosphate Fertilizer 
Production NESHAP, subpart BB to eliminate the SSM exemption. 
Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008), the 
EPA has established standards in this rule that apply at all times. 
Appendix A of subpart BB (the General Provisions Applicability Table) 
is being revised to change several references related to requirements 
that apply during periods of SSM. We also eliminated or revised certain 
recordkeeping and reporting requirements related to the eliminated SSM 
exemption. The EPA also made changes to the rule to remove or modify 
inappropriate, unnecessary, or redundant language in the absence of the 
SSM exemption. For this source category, we determined that work 
practice standards for periods of startup and shutdown are appropriate 
in lieu of numeric emission limits due to the short duration of startup 
and shutdown, and control devices used on the various process lines in 
this source category are effective at achieving desired emission 
reductions immediately upon startup (79 FR 66551). Therefore, we are 
finalizing in NESHAP subpart BB the proposed work practice standards 
for periods of startup and shutdown. However, in consideration of 
comments received during the public comment period, we are making 
changes to the work practice standards in order to clarify that the 
standard applies in lieu of numeric emission limits and how compliance 
with the standard is demonstrated. In order to comply with the work 
practice standard, facilities must monitor the same control device 
operating parameters and comply with the same operating limits that are 
established to otherwise comply with the emission limits. Additionally, 
we added a definition of ``startup'' and ``shutdown'' in the 
definitions section of the final rule to specify when startup begins 
and ends, and when shutdown begins and ends. See section VI.D.3 of this 
preamble for details on these changes.

E. What other changes are we making to the NESHAP and NSPS for the 
Phosphate Fertilizer Production source category?

    Today's rule also finalizes, as proposed, revisions to several 
other Phosphate Fertilizer Production NESHAP and NSPS requirements. We 
are finalizing, as proposed, changes to clarify applicability and 
certain definitions, as follows:

     Adopting the proposed conditions in NESHAP subpart BB 
that exclude the use of evaporative cooling towers for any liquid 
effluent from any wet scrubbing device installed to control HF 
emissions from process equipment; and
     Finalizing the proposed revisions changing the word 
``cookers'' in NSPS subpart W to ``coolers.''

    We are finalizing, as proposed, several changes to testing, 
monitoring, recordkeeping, and reporting to provide consistency, 
clarification, and flexibility, as follows:

     Finalizing the proposed revisions to NESHAP subpart BB 
that require a minimum pressure drop of 5 inches of water column for 
facilities that use pressure differential in parametric monitoring;

[[Page 50394]]

     Finalizing the proposal to remove the requirement in 
NESHAP subpart BB that facilities must request and obtain approval 
of the Administrator for changing operating limits;
     Adopting the proposed monitoring requirements for 
fabric filters in NESHAP subpart BB;
     Adopting the proposed addition of a site-specific 
monitoring plan and calibration requirements for CMS in NESHAP 
subpart BB;
     Adopting the proposed term ``absorber'' in lieu of 
``scrubber'' in NESHAP subpart BB;
     Adopting the proposed format of NESHAP subpart BB to 
reference tables for emissions limits and monitoring requirements;
     Adopting the proposed provisions in NSPS subpart V, 
NSPS subpart W, and NSPS subpart X that require the owner or 
operator to establish an allowable range for the pressure drop 
through the process scrubbing system, keep records of the daily 
average pressure drop through the process scrubbing system, and keep 
records of deviations;
     Adopting the proposed term ``absorber'' in lieu of 
``scrubbing system'' in NSPS subpart V; and
     Adopting the proposed term ``absorber'' in lieu of 
``process scrubbing system'' in NSPS subpart W and NSPS subpart X.

    We are also finalizing changes to the NESHAP and NSPS for the 
Phosphate Fertilizer Production source category on issues raised in 
response to the proposed rulemaking, as follows (refer to section 
VI.E.2 of this preamble for further details):

     Revising the definitions of ``phosphate fertilizer 
process line'' and ``phosphate fertilizer production plant'' in 
NESHAP subpart BB to reference granular phosphate fertilizer;
     Finalizing liquid-to-gas ratio monitoring in NESHAP 
subpart BB for low-energy absorbers (i.e., absorbers that are 
designed to operate with pressure drops of 5 inches of water column 
or less) in lieu of monitoring influent liquid flow and pressure 
drop through the absorber;
     Clarifying in NESHAP subpart BB that during the most 
recent performance test, if owners or operators demonstrate 
compliance with the emission limit while operating their control 
device outside the previously established operating limit, owners or 
operators must establish a new operating limit based on that most 
recent performance test and notify the Administrator that the 
operating limit changed based on data collected during the most 
recent performance test; and
     Clarifying in NESHAP subpart BB that facilities not be 
required to obtain approval, and, instead, immediately comply with a 
new operating limit when it is developed and submitted to the 
Administrator.

F. What are the effective and compliance dates of the standards for the 
Phosphate Fertilizer Production source category?

    The revisions to the NSPS and NESHAP standards being promulgated in 
this action for the Phosphate Fertilizer Production source category are 
effective on August 19, 2015.
    The compliance date in NESHAP subpart BB for when to install, 
calibrate, and maintain a bag leak detection system on a fabric filter 
is August 19, 2016. We believe that 1 year is necessary because some 
facilities that currently operate a fabric filter do not have a bag 
leak detection system and will need time to purchase and install this 
compliance monitoring equipment and implement quality assurance 
measures.
    The compliance date in NESHAP subpart BB for the revised startup 
and shutdown requirements is August 19, 2015. We determined that the 
feasibility of operating the control devices used to control HAP 
emissions from phosphate fertilizer production is not limited by 
specific process operating conditions.
    Finally, to ensure continuous compliance with the standard, the 
compliance date for the monitoring and recordkeeping requirements in 
NSPS subparts V, W, and X for all new granular DAP plants, TSP plants, 
and GTSP storage facilities is August 19, 2015, or upon startup, 
whichever is later.

G. What are the requirements for submission of performance test data to 
the EPA for the Phosphate Fertilizer Production source category?

    As stated in the preamble to the proposed rule, the EPA is taking a 
step to increase the ease and efficiency of data submittal and data 
accessibility. Specifically, the EPA is requiring owners and operators 
of phosphate fertilizer facilities to submit electronic copies of 
certain required performance test reports.
    As mentioned in the preamble of the proposal, data will be 
collected by direct computer-to-computer electronic transfer using EPA-
provided software. As discussed in the proposal, the EPA-provided 
software is an electronic performance test report tool called the 
Electronic Reporting Tool (ERT). The ERT will generate an electronic 
report package which will be submitted to the Compliance and Emissions 
Data Reporting Interface (CEDRI) and then archived to the EPA's Central 
Data Exchange (CDX). A description and instructions for use of the ERT 
can be found at http://www.epa.gov/ttn/chief/ert/index.html, and CEDRI 
can be accessed through the CDX Web site at www.epa.gov/cdx.
    The requirement to submit performance test data electronically to 
the EPA does not create any additional performance testing and will 
apply only to those performance tests conducted using test methods that 
are supported by the ERT. A listing of the pollutants and test methods 
supported by the ERT is available at the ERT Web site. The EPA 
believes, through this approach, industry will save time in the 
performance test submittal process. Additionally, this rulemaking 
benefits industry by cutting back on recordkeeping costs as the 
performance test reports that are submitted to the EPA using CEDRI are 
no longer required to be kept in hard copy.
    As mentioned in the proposed preamble, state, local, and tribal 
agencies will benefit from more streamlined and accurate review of 
performance test data that will be available on the EPA WebFIRE 
database. The public will also benefit. Having these data publicly 
available enhances transparency and accountability. For a more thorough 
discussion of electronic reporting of performance tests using direct 
computer-to-computer electronic transfer and using EPA-provided 
software, see the discussion in the preamble of the proposal.
    In summary, in addition to supporting regulation development, 
control strategy development, and other air pollution control 
activities, having an electronic database populated with performance 
test data will save industry, state, local, and tribal agencies, and 
the EPA significant time, money, and effort while improving the quality 
of emission inventories, air quality regulations, and enhancing the 
public's access to this important information.

V. What is the rationale for our final decisions and amendments for the 
Phosphoric Acid Manufacturing source category?

    For each issue related to the Phosphoric Acid Manufacturing source 
category, this section provides a description of what we proposed and 
what we are finalizing for the issue, the EPA's rationale for the final 
decisions and amendments, and a summary of key comments and responses. 
For all comments not discussed in this preamble, comment summaries and 
the EPA's responses can be found in the Comment Summary and Response 
document available in the docket.

[[Page 50395]]

A. Residual Risk Review for the Phosphoric Acid Manufacturing Source 
Category

1. What did we propose pursuant to CAA section 112(f) for the 
Phosphoric Acid Manufacturing source category?
    Pursuant to CAA section 112(f), we conducted a residual risk review 
and presented the results of this review, along with our proposed 
decisions regarding risk acceptability and ample margin of safety, in 
the November 7, 2014, proposed rule for the Phosphoric Acid 
Manufacturing NESHAP (79 FR 66512). The results of the risk assessment 
are presented briefly below in Table 2 of this preamble, and in more 
detail in the residual risk document, ``Residual Risk Assessment for 
Phosphate Fertilizer Production and Phosphoric Acid Manufacturing 
Source Categories in support of the July 2015 Risk and Technology 
Review Final Rule,'' which is available in the docket for this 
rulemaking.

                                         Table 2--Human Health Risk Assessment for Phosphoric Acid Manufacturing
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Cancer MIR (in 1                                         Max chronic non-cancer
                                                 million)           Cancer    Population  Population            HI
                                         ------------------------  incidence  with risks  with risks ------------------------  Worst-case max acute non-
 Category & number of facilities modeled   Based on    Based on   (cases per   of 1-in-1  of 10-in-1   Based on    Based on            cancer HQ
                                            actual     allowable     year)    million or  million or    actual     allowable
                                           emissions   emissions                 more        more      emissions   emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Phosphoric Acid (12 facilities).........        0.09        0.09      0.0002           0           0         0.2         0.3  HQREL = 2 (hydrofluoric
                                                                                                                               acid)
                                                                                                                              HQAEGL - 1 = 0.6
                                                                                                                               (hydrofluoric acid).
Facility-wide (12 facilities)...........         0.5  ..........       0.001           0           0         0.2
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on actual emissions for the Phosphoric Acid Manufacturing 
source category, the maximum individual risk (MIR) was estimated to be 
less than 1-in-1 million, the maximum chronic non-cancer target organ-
specific hazard index (TOSHI) value was estimated to be up to 0.2, and 
the maximum off-site acute hazard quotient (HQ) value was estimated to 
be up to 2. The total estimated national cancer incidence from this 
source category, based on actual emission levels, was 0.0002 excess 
cancer cases per year, or one case in every 5,000 years. Based on MACT-
allowable emissions for the Phosphoric Acid Manufacturing source 
category, the MIR was estimated to be less than 1-in-1 million, and the 
maximum chronic non-cancer TOSHI value was estimated to be up to 0.3. 
We also found there were emissions of several persistent and bio-
accumulative HAP (PB-HAP) with an available RTR multipathway screening 
value, and with the exception of Hg and cadmium compounds, the reported 
emissions of these HAP (i.e., lead compounds, dioxin/furan compounds, 
and polycyclic organic matter (POM) compounds), were below the 
multipathway screening value for each compound. One facility emitted 
divalent Hg (Hg\2+\) above the Tier I screening threshold level, 
exceeding the screening threshold by a factor of 7 and the cadmium 
emissions exceeded the cadmium screening threshold by a factor of 2. 
Consequently, we conducted a Tier II screening assessment, in which 
both pollutants of concern were below the Tier II screening threshold, 
indicating no potential for multipathway impacts of concern from this 
facility. The maximum facility-wide MIR was less than or equal to 1-in-
1 million and the maximum facility-wide TOSHI was 0.2. We weighed all 
health risk factors in our risk acceptability determination, and we 
proposed that the residual risks from the Phosphoric Acid Manufacturing 
source category are acceptable.
    We then considered whether the Phosphoric Acid Manufacturing NESHAP 
provides an ample margin of safety to protect public health and 
prevents, taking into consideration costs, energy, safety, and other 
relevant factors, an adverse environmental effect. In considering 
whether the standards should be tightened to provide an ample margin of 
safety to protect public health, we considered the same risk factors 
that we considered for our acceptability determination and also 
considered the costs, technological feasibility, and other relevant 
factors related to emissions control options that might reduce risk 
associated with emissions from the source category. We proposed that 
the current standards provided an ample margin of safety to protect 
public health. With respect to adverse environmental effects, none of 
the individual modeled concentrations for any facility in the source 
category exceeded any of the ecological benchmarks (either the lowest-
observed-adverse-effect level (LOAEL) or no-observed-adverse-effect 
level (NOAEL)). Based on the results of our screening analysis for 
risks to the environment, we also proposed that the current standards 
prevent an adverse environmental effect.
2. How did the risk review change for the Phosphoric Acid Manufacturing 
source category?
    The residual risk review for the Phosphoric Acid Manufacturing 
source category did not change since proposal (79 FR 66512). 
Accordingly, we are not tightening the standards under section 
112(f)(2) based on the residual risk review, and are thus readopting 
the existing standards under section 112(f)(2).
3. What key comments did we receive on the risk review, and what are 
our responses?
    The comments received on the proposed residual risk review were 
generally supportive of our determination of risk acceptability and 
ample margin of safety analysis. However, we received several comments 
requesting we make changes to the residual risk review, including:

     Update the residual risk review with the 
recommendations and information from the National Academy of 
Sciences (NAS);
     Incorporate the best currently available information on 
children's exposure to lead, and go beyond using the 2008 Lead 
National Ambient Air Quality Standards (NAAQS);
     Reevaluate whether the residual risk review is 
consistent with the key recommendations made by the Science Advisory 
Board (SAB);
     Clarify in the rulemaking docket that data received by 
industry were commensurate with the relevant statutory obligations;
     Revise HF emission data because they are not 
representative of actual HF emissions, but rather overestimate 
emissions causing the residual risk review to have an overtly 
conservative bias;

[[Page 50396]]

     Reconsider the assumption used in the NESHAP residual 
risk assessment that all chromium is hexavalent chromium;
     Revise certain stack parameters used in the analysis;
     Clarify meteorological data used in the analysis;
     Adequately explain rationale for the maximum 1-hour 
emission rate used for determining potential acute exposures;
     Clarify the selection of ecological assessment 
endpoints; and
     Provide some quantitative or qualitative rationale for 
the characterization of the exposure modeling uncertainty.

    We evaluated the comments and determined that no changes were 
needed. Since none of these comments had an effect on the final rule, 
their summaries and corresponding EPA responses are not included in 
this preamble. A summary of these comments and our responses can be 
found in the Comment Summary and Response document available in the 
docket for this action (EPA-HQ-OAR-2012-0522).
4. What is the rationale for our final approach and final decisions for 
the risk review?
    For the reasons explained in the proposed rule, we determined that 
the risks from the Phosphoric Acid Manufacturing source category are 
acceptable, the current standards provide an ample margin of safety to 
protect public health, and prevent an adverse environmental effect. 
Since proposal, neither the risk assessment nor our determinations 
regarding risk acceptability, ample margin of safety or adverse 
environmental effects have changed. Therefore, pursuant to CAA section 
112(f)(2), we are finalizing our residual risk review as proposed.

B. Technology Review for the Phosphoric Acid Manufacturing Source 
Category

1. What did we propose pursuant to CAA section 112(d)(6) for the 
Phosphoric Acid Manufacturing source category?
    Pursuant to CAA section 112(d)(6), we conducted a technology 
review, which focused on identifying and evaluating developments in 
practices, processes, and control technologies for the emission sources 
in the Phosphoric Acid Manufacturing source category. At proposal, we 
did not identify cost-effective developments in practices, processes, 
or control technologies that warrant revisions to the NESHAP for this 
source category. More information concerning our technology review can 
be found in the memorandum, ``CAA Section 111(b)(1)(B) and 112(d)(6) 
Reviews for the Phosphoric Acid Manufacturing and Phosphate Fertilizer 
Production Source Categories,'' which is available in the docket, and 
in the preamble to the proposed rule, 79 FR 66538-66539.
2. How did the technology review change for the Phosphoric Acid 
Manufacturing source category?
    The technology review for the Phosphoric Acid Manufacturing source 
category did not change since proposal (79 FR 66512). Therefore, we are 
not revising NESHAP subpart AA based on the technology review.
3. What key comments did we receive on the technology review, and what 
are our responses?
    Commenters agreed with our conclusion that there are no new cost-
effective developments in practices, processes, or control technologies 
that can be applied to the Phosphoric Acid Manufacturing source 
category that would reduce HAP emissions below current levels.
4. What is the rationale for our final approach for the technology 
review?
    For the reasons explained in the proposed rule, we concluded that 
additional standards are not necessary pursuant to CAA section 
112(d)(6); therefore, we are not finalizing changes to NESHAP subpart 
AA as part of our technology review.

C. CAA Sections 112(d)(2), 112(d)(3), and 112(h) for the Phosphoric 
Acid Manufacturing Source Category

1. What did we propose pursuant to CAA sections 112(d)(2), 112(d)(3), 
and 112(h) for the Phosphoric Acid Manufacturing source category?
    We proposed MACT standards for HF and Hg pursuant to CAA sections 
112(d)(2) and 112(d)(3), and work practice standards pursuant to CAA 
section 112(h), for phosphate rock calciners, an emissions source that 
was initially regulated for HAP metals using PM as a surrogate. We 
proposed regulating two pollutants, Hg and HF, which were not directly 
regulated under the initial NESHAP subpart AA. We proposed eliminating 
the use of PM as a surrogate for Hg and proposed a Hg emission limit 
for phosphate rock calciners. Because control devices may be necessary 
to meet the proposed Hg limits for phosphate rock calciners, we 
proposed monitoring and testing requirements in NESHAP subpart AA for 
the two types of control systems evaluated as alternatives for control 
of Hg: Adsorbers (typically fixed bed carbon), and sorbent injection 
(i.e., activated carbon injection (ACI)) followed by a wet 
electrostatic precipitator (WESP) or followed by fabric filtration. We 
also proposed the addition of methods to monitor emissions of Hg using 
continuous emissions monitoring systems (CEMS). We also proposed a 
maximum calcination temperature of less than 1,600 degrees Fahrenheit 
for phosphate rock calciners as a work practice standard to control HF 
emissions. In addition to proposing a maximum calcination temperature, 
we proposed to require that emissions from phosphate rock calciners be 
routed to an absorber to limit emissions of HF from phosphate rock 
calciners.
    Also, we did not propose revised emissions limits for rock dryers 
because this process is no longer used in the NESHAP regulated source 
categories for phosphoric acid or phosphate fertilizer (i.e., the rock 
dryers that were previously used in this industry are no longer in 
operation).
    Finally, we proposed a work practice applicable to facilities when 
new gypsum dewatering stacks are constructed that would limit the size 
of active gypsum dewatering stacks and control fugitive HF emissions. 
When new gypsum dewatering stacks are constructed, we proposed that the 
ratio of total active gypsum dewatering stacks area (i.e., sum of the 
footprint acreage of all existing and new active gypsum dewatering 
stacks combined) to annual phosphoric acid manufacturing capacity must 
not be greater than 80 acres per 100,000 tons of annual phosphoric acid 
manufacturing capacity (equivalent P2O5 feed). As 
we stated in the preamble to the proposed rule, limiting the size of 
gypsum dewatering stacks would minimize emissions by creating an upper 
bound on emissions. We also proposed work practice standards to control 
HF emissions from gypsum dewatering stacks and cooling ponds. We 
proposed a list of control techniques for facilities to use in 
development of a site-specific gypsum dewatering stack and cooling pond 
management plan to control fugitive HF emissions. Unless the active 
gypsum dewatering stack or cooling pond commenced construction or 
reconstruction after the date of publication of the final rule, we 
proposed that each facility use at least one of these control 
techniques. For each active gypsum dewatering stack or cooling pond 
that commenced construction or reconstruction after the date of 
publication of the final rule, we proposed that each facility use two 
of the listed control techniques.

[[Page 50397]]

2. How did our final rule change from what we proposed pursuant to CAA 
sections 112(d)(2), 112(d)(3), and 112(h) for the Phosphoric Acid 
Manufacturing source category?
    In consideration of comments received during the public comment 
period for the proposed rulemaking, we are finalizing the proposed BTF 
Hg limit in NESHAP subpart AA for new phosphate rock calciners. We are 
not finalizing the proposed BTF Hg limit in NESHAP subpart AA for 
existing phosphate rock calciners. Instead, we are finalizing a MACT 
floor Hg limit for existing phosphate rock calciners based on the 
results of the MACT floor calculations for Hg that are discussed in the 
preamble of the proposed rule (79 FR 66533). We are also revising our 
estimated costs in the final rule as discussed in section V.C.3.a.i of 
this preamble. In addition, we are not finalizing work practice 
standards for HF from phosphate rock calciners, as proposed. Instead, 
as discussed in section V.C.3.a.ii of this preamble, we are including a 
total fluoride emission limit for phosphate rock calciners in NESHAP 
subpart AA.
    Also, in consideration of comments received (see section V.C.3.b.i 
of this preamble for details), we are not adopting the proposed work 
practice in NESHAP subpart AA that limits the size of active gypsum 
dewatering stacks (which would have been applicable to facilities when 
new gypsum dewatering stacks are constructed). Lastly, we are 
finalizing in NESHAP subpart AA the work practice standard as proposed 
that requires owners or operators to prepare and operate in accordance 
with a gypsum dewatering stack and cooling pond management plan. 
However, based on analysis of public comments, we are making several 
changes to the specific control techniques that we proposed as options 
in the plan for controlling fugitive HF emissions (see section 
V.C.3.b.ii of this preamble for details on these changes).
3. What key comments did we receive on what we proposed pursuant to CAA 
sections 112(d)(2), 112(d)(3), and 112(h), and what are our responses?
    We received several comments regarding the proposed addition of 
numeric emission limits for Hg and work practice standards for HF 
emissions from phosphate rock calciners, and the addition of gypsum 
dewatering stack and cooling pond work practices for the Phosphoric 
Acid Manufacturing source category. The following is a summary of the 
significant comments we received regarding these topics and our 
responses to them. Other comments received and our responses to those 
comments can be found in the Comment Summary and Response document 
available in the docket for this action (EPA-HQ-OAR-2012-0522).
    a. MACT and Work Practice Standards for Phosphate Rock Calciners--
i. Hg Emission Limits for Phosphate Rock Calciners--Comment. Some 
commenters did not support the EPA's decision to set a BTF limit for Hg 
from phosphate rock calciners because the emissions do not present 
unacceptable risks nor do the emission limits yield any benefits. The 
commenters stated that the EPA fails to show that the proposed BTF Hg 
limit would produce health or environmental benefits that justify the 
costs of achieving the standard as they assert is required by CAA 
section 112(d)(2). Commenters further claimed that the EPA's own risk 
assessment shows that the BTF limit is not necessary from a risk 
standpoint because the NESHAP regulation, prior to implementation of 
the proposed Hg BTF limits, provides an ample margin of safety to 
protect public health and prevents, taking into consideration costs, 
energy, safety, and other relevant factors, an adverse environmental 
effect. The commenters maintained that under CAA section 112(d)(2), the 
EPA may set an emission limit that is more stringent than the MACT 
floor only if the Agency determines that the BTF limit is 
``achievable'' based on a consideration of the relative costs and 
benefits. One commenter cited regulations where the EPA did not set BTF 
limits for a particular pollutant because the benefits were minimal and 
the risk would not be appreciably reduced. Commenters supported setting 
the MACT floor as the Hg limit.
    Commenters stated the Hg control devices that the EPA evaluated for 
the phosphate rock calciner BTF limit were not technically feasible, 
but did note two potential solutions. Specifically, the commenters 
stated that use of ACI just prior to the existing WESP or after the 
WESP with a fabric filter is not technically feasible. The commenters 
explained the exhaust gas downstream of the WESP is completely 
saturated and contains entrained water droplets; this would plug the 
fabric filter, result in performance degradation of the activated 
carbon, and could lead to plugging of the injection lances and 
formation of deposits on the ducts. The commenters further explained 
that it would not be feasible to install heating systems or design 
engineering control to avoid these problems, due to high costs and the 
technical complexity. The commenters noted that installing the ACI just 
prior to the WESP was also not feasible, again due to performance 
degradation of the activated carbon, but also due to the fact that the 
existing WESPs could not capture the additional particulate load. The 
commenters reported that installing the ACI upstream of the existing 
venturi scrubber is technically feasible, because the gas upstream of 
the scrubber is not completely saturated. However, the commenters noted 
several design and operational modifications that would be necessary; 
these modifications focused on reducing the temperature of the exhaust 
gas streams to less than 375 degrees Fahrenheit. When installing ACI 
upstream of the existing venturi scrubber, the ACI vendor used by the 
commenter recommended the use of treated (e.g., halogenated) carbon at 
an injection rate of 30 lb/MMacf, in order to meet the BTF Hg limit. 
The commenter said that the carbon injection rate may need to be as 
much as 30 lb/MMacf based on site-specific conditions, such as 
temperature, Hg concentration, moisture, and sulfur content of the 
phosphate rock calciner exhaust stream. In support of a high injection 
rate, the commenter also cited a reference from 1994 that observed an 
increased injection rate was necessary due to temperature of the 
exhaust gas stream.
    Regarding fixed-bed carbon adsorption, commenters stated a 
traditional fixed-bed carbon adsorption system would not be feasible 
due to the presence of entrained water droplets that would severely 
degrade sorbent performance and cause plugging within the bed. The 
commenters indicated that new Gore Mercury Control System (GMCS) 
technology might be technically feasible because it uses a fixed 
sorbent structure with a sorbent polymer composite material to adsorb 
Hg; the GMCS polymer composite material might protect the sorbent from 
entrained water droplets and other contaminants in the flue gas. The 
commenters stated that to use a GMCS fixed-bed carbon adsorption 
system, several adjustments to the calciners would be necessary, as 
well as a pilot study to confirm the feasibility. Another commenter 
also reported they were evaluating the use of the GMCS system, but were 
only in preliminary stages as their phosphate rock calciner is not yet 
operating. A commenter also explained that each phosphate rock calciner 
would need its own controls and a single control system for all 
phosphate rock calciners

[[Page 50398]]

would not be feasible due to safety and operational concerns.
    Several commenters argued that ACI and fixed-bed carbon adsorption 
were not cost effective for controlling Hg emissions from phosphate 
rock calciners. Two commenters reported a site-specific cost estimate 
for installing GMCS fixed-bed carbon adsorption downstream of the 
existing WESP, with capital costs of $32 million and annual costs of 
$5.8 million; the resulting cost-effectiveness was approximately 
$40,000 per pound of Hg. The commenters noted the GMCS cost-
effectiveness ($40,000/lb Hg) was much higher than the cost-
effectiveness the EPA presented in the proposed rule ($8,000/lb Hg) for 
a traditional fixed-bed carbon adsorption system. Commenters also 
reported a site-specific cost estimate for installing ACI upstream of 
the existing venturi scrubbers, with capital costs of $21.1 million and 
annual costs of $9.1 million; this resulted in a cost-effectiveness of 
approximately $63,000 per pound of Hg. The commenters noted this ACI 
cost-effectiveness ($63,000/lb Hg) was much higher than the cost-
effectiveness the EPA presented in the proposed rule ($12,100/lb Hg) 
for ACI. The commenters stated that because their costs for ACI and 
GMCS fixed-bed carbon adsorption were site-specific, they are much more 
representative than the costs developed by the EPA for the proposed 
rule. Finally, one commenter stressed that the site-specific Hg control 
cost-effectiveness numbers were well above the cost-effectiveness for 
other rules where the EPA implemented BTF Hg controls. Another 
commenter noted that preliminary information for installing Hg controls 
resulted in estimates of $17.5 million in capital costs and $10 million 
for annual costs.
    Response. Based on these comments, the Agency revised the BTF costs 
analysis and determined that setting a BTF Hg emission limit for 
existing phosphate rock calciners would impose a significant economic 
impact to PotashCorp (PCS) Aurora, the only facility that we are aware 
of with phosphate rock calciners; therefore, we are not finalizing the 
BTF Hg limit for existing phosphate rock calciners. The annualized 
control costs for this company would be approximately 0.9 percent to 
5.3 percent of revenues (see ``PCS Phosphate Response to USEPA Request 
for Aurora Plant Financial Information, May 8, 2015,'' which is 
available in the docket for this rulemaking). While these costs are 
small for the industry, they may be significant for the company and 
particularly significant for the facility. For the company, there may 
be a negative impact on profitability. If the company is unable to pass 
on the increase in the cost of manufacturing the product by raising 
prices, the facility will either face a potentially significant 
reduction in profitability or have to close a process or facility. 
Therefore, the Agency is finalizing a MACT floor Hg limit of 0.14 
milligrams (mg) Hg per dry standard cubic meter (dscm) at 3-percent 
O2 for existing phosphate rock calciners and does not 
anticipate that any facilities will need to install a new control 
device to meet the existing phosphate rock calciner Hg limit. Also, we 
are finalizing the proposed BTF Hg limit (i.e., 0.014 mg Hg/dscm at 3-
percent O2) for new phosphate rock calciners, as facilities 
should be better able to plan for the costs of controls for new 
sources. The following discussion provides the details of these 
decisions.
    The results of the residual risk analyses are not part of the BTF 
MACT determination, and, accordingly, the commenters' concern about not 
considering risk results is not appropriate. See Sierra Club v. EPA, 
353 F.3d 976, 981 (D.C. Cir. 2004). Analyzing the risk would not be a 
practical requirement, as, typically, MACT standards are set in advance 
of a residual risk or technology review of the standard. Additionally, 
the statutory language excerpt cited by the commenter does not 
accurately reflect the CAA language, which requires the Agency to 
consider costs associated with the emission reductions, but does not 
require a demonstration of benefits. The Agency appropriately met its 
requirements under CAA section 112(c) and (d) by first evaluating a 
MACT floor level of control for Hg emissions from phosphate rock 
calciner units and then evaluating cost-effective controls for further 
reducing emissions BTF level.
    The Agency appreciates the commenters' site-specific review of Hg 
control device technologies and agrees with the commenters' revisions 
to certain aspects of the technical feasibility of ACI and fixed-bed 
carbon adsorption. At proposal, we noted that high moisture streams may 
result in plugging of the fabric filter, as it relates to ACI use. 
However, we did not consider that entrained water droplets in the high 
moisture streams would degrade carbon sorbent performance for both ACI 
and fixed-bed carbon adsorption, or lead to plugging within a fixed-
bed. As a result of the additional information provided by the 
commenters, we agree that it is not technically feasible to use ACI 
just prior to the existing WESP or after the WESP with a fabric filter 
to control Hg emissions from phosphate rock calciners, based on current 
operations. Based on information available at this time, we also agree 
that a traditional fixed-bed carbon adsorption system is not 
technically feasible to control Hg emissions from phosphate rock 
calciners.
    The commenters also stated, and the EPA agrees, that use of ACI 
(specifically halogenated carbon) is technically feasible to control Hg 
emissions from phosphate rock calciners if ACI is installed upstream of 
the existing venturi scrubber, where the moisture content is lower. 
However, we disagree with the commenters' assessment that a carbon 
injection rate of 30 lb/MMacf would be necessary to achieve a 90 
percent reduction in Hg emissions from phosphate rock calciners. The 
commenters' carbon injection rate estimate is much higher than ACI 
installations at coal power plants and cement kilns, and while 
phosphate rock calciners may have unique exhaust gas properties, these 
properties do not warrant such an extreme carbon feed rate.
    To provide additional context on carbon injection rates, we 
reviewed numerous ACI Hg reduction studies conducted through a National 
Energy Technology Laboratory (NETL) research program under the 
Department of Energy (DOE), as well as other studies, which are 
available in Docket ID No. EPA-HQ-OAR-2012-0522. In our review, we 
considered the impact on carbon injection rates due to temperature, 
moisture content, Hg concentration, sulfur content (i.e., sulfur 
trioxide (SO3) concentration), and carbon sorbent type. 
Considering the information in these studies, we found it common for 
carbon injection rates of 5 lb/MMacf or less to result in 90 percent Hg 
removal, although higher injection rates are warranted in some 
instances. We also found that at certain facilities, high injection 
rates do not result in 90 percent Hg removal; however, in several of 
these cases those data are for standard powdered activated carbon 
(PAC), i.e., activated carbon that has not been treated with halogens, 
or exhaust gases containing high SO3 concentrations. 
Specifically, we identified a 2008 document \3\ that combines results 
from several studies demonstrating the relationship between PAC 
injection rate (lb/MMacf) and percent Hg removal. While Figure 2 in 
this 2008 document shows injection rates up to 20 lb/MMacf using 
standard

[[Page 50399]]

PAC (e.g., not halogenated carbon), data for halogenated PAC, in Figure 
3 of the 2008 document, shows a maximum of approximately 9 lb/MMacf in 
order to achieve 90 percent Hg removal from the gas stream. It accords 
with our general knowledge that standard PAC can have a high control 
efficiency if halogens are present in the flue gas to oxidize elemental 
Hg so that it can be adsorbed on the particles injected and 
subsequently captured in the particle control device. Thus, if halogens 
are not present in sufficient quantities to oxidize the elemental Hg 
present, the unoxidized Hg present will continue to be emitted, since 
it would not be adsorbed on the particles and captured in the particle 
control device. This situation can be remedied through the use of 
halogenated PAC, which will oxidize the elemental Hg present so that it 
can be adsorbed on the particles and later captured. Thus, while we 
agree with the vendor's recommendation that halogenated PAC is most 
likely to result in better Hg removal efficiencies for the phosphate 
rock calciners, we disagree with the relevance of the commenter's cited 
1994 document. The ACI vendor used by the commenter recommended treated 
(e.g., halogenated) PAC as the most likely sorbent type for phosphate 
rock calciner Hg treatment and the cited 1994 document evaluated 
standard PAC. In addition, as noted above, there have been more recent 
studies and significant progress in PAC design since 1994, and as such 
we do not believe the PAC evaluated in the 1994 document would result 
in the Hg reductions that today's PAC can achieve. Therefore, we 
determined that PAC type is a critical factor for Hg removal 
efficiencies for this source category.
---------------------------------------------------------------------------

    \3\ Refer to Figures 2 and 3 of ``DOE NETL Hg Field Testing 
Update_2008'' which is available in Docket ID No. EPA-HQ-OAR-2012-
0522.
---------------------------------------------------------------------------

    The commenter also noted that modifications focused on reducing the 
temperature of the exhaust gas streams would be necessary in order for 
ACI to be effective when installed prior to the existing venturi 
scrubber. This reduced operating temperature for the phosphate rock 
calciner exhaust would be in a similar range as coal utility boilers; 
it is common for coal utility boilers to have exhaust gases at 
temperatures exceeding 300 degrees Fahrenheit (see the documents ``Coal 
Plant Hg Controls Update_EPA_2005'' and ``DOE NETL Hg Field Testing 
Update_2008,'' which are available in Docket ID No. EPA-HQ-OAR-2012-
0522). Therefore, the cited coal utility boiler studies are appropriate 
and show that ACI is effective in the new temperature range. This 
further refutes the commenter's citation of the 1994 document regarding 
temperature concerns and the necessity of an injection rate as high as 
30 lb/MMacf.
    Data are available demonstrating that increased SO3 
levels are detrimental to sorbent performance. We found that higher 
carbon injection rates are typical for plants with higher 
SO3 concentration in the exhaust stream; for coal utility 
boilers, this can occur when the fuel is high-sulfur bituminous coal. 
The concentration of SO3 in emissions from coal utility 
boilers is also increased by certain control devices (e.g., selective 
catalytic reduction) that do not exist at the phosphate rock calciners. 
For information on SO3 impacts, see the documents ``DOE NETL 
Hg Field Testing Update_2008'' and ``ADA ACI Overview_2010,'' which are 
available in Docket ID No. EPA-HQ-OAR-2012-0522. Of note, certain PAC 
sorbents are designed to work in high-sulfur environments (see the 
document ``Calgon Fluepac ST brochure,'' available in Docket ID No. 
EPA-HQ-OAR-2012-0522). Based on this available information, we do not 
believe SO3 concentration in the phosphate rock calciner 
exhaust gas stream will severely impact ACI performance to a level 
requiring a carbon injection rate of 30 lb/MMacf.
    Additionally, we identified a pilot study that was conducted in 
2007 on a cement kiln at the Ash Grove Durkee facility that resulted in 
more than 90 percent Hg removal efficiencies using carbon injection 
rates of only 3 lb/MMacf. Of note, the Hg concentration in the cement 
kiln exhaust gas was more than 10 times higher than the Hg 
concentration in the phosphate rock calciner exhaust gas. This study is 
presented in the document ``Carbon Injection Pilot Test Durkee 
OR_2007,'' available in Docket ID No. EPA-HQ-OAR-2012-0522.
    While we acknowledge that phosphate rock calciner exhaust streams 
may have certain unique characteristics, we do not agree with a PAC 
injection rate of 30 lb/MMacf based on the data available, as discussed 
above. We believe a halogenated PAC injection rate of 10 lb/MMacf or 
lower (for ACI installed upstream of the existing venturi scrubbers) is 
sufficient for meeting the BTF Hg limit for phosphate rock calciners.
    Commenters also noted, and the EPA agrees, that GMCS technology 
would be technically feasible to control Hg emissions from phosphate 
rock calciners. We also agree that individual GMCS fixed-bed carbon 
adsorption systems would be necessary for each of the six phosphate 
rock calciners. The commenters noted that two full-scale operations are 
actively using GMCS fixed-bed carbon adsorption systems to control Hg. 
Furthermore, based on additional discussion with industry (see ``EPA 
Meeting Minutes for PCS Aurora Hg Discussion, March 12, 2015,'' which 
is available in Docket ID No. EPA-HQ-OAR-2012-0522), we now know that 
three full-scale operations use GMCS to control Hg, with two additional 
operations to come online soon. These full-scale operations are located 
at coal power plants, not phosphoric acid manufacturing processes. 
Based on the vendor-provided information and the fact that GMCS 
technology is currently used at coal power plants to comply with Hg 
emission limits, we believe GMCS technology is technically feasible. In 
regards to the need for a pilot study, facilities would have time to 
design, construct, and test the system.
    Although we have determined that two control technologies are 
technically feasible to control Hg emissions from phosphate rock 
calciners, we evaluated costs for the BTF Hg limit based on the 
estimated lower cost technology, installation of halogenated ACI 
upstream of the existing venturi scrubber. We used the ACI cost data 
provided by the commenter to estimate the costs for complying with the 
BTF Hg limit. However, instead of basing the annual carbon cost on an 
injection rate of 30 lb/MMacf, we applied injection rates of 5 and 10 
lb/MMacf of halogenated carbon for reasons stated above. As provided by 
the commenter, the capital cost for installing six ACI units on each 
existing phosphate rock calciner is approximately $21,150,000. The 
annual cost ranges from approximately $4,320,000 (when a carbon 
injection rate of 5 lb/MMacf is used) to approximately $5,280,000 (when 
a carbon injection rate of 10 lb/MMacf is used); this results in Hg 
reductions of 145 pounds of Hg per year. As previously stated, these 
annual costs imposed a significant economic burden and we are not 
finalizing the BTF Hg limit for existing phosphate rock calciners.
    Existing phosphate rock calciners must comply with a Hg emission 
limit that equals the MACT floor at 0.14 mg Hg/dscm at 3-percent 
O2. The MACT floor was calculated using the upper prediction 
limit (UPL) methodology, which was discussed in the preamble of the 
proposed rule (see 79 FR 66533) and is also discussed in the 
memorandums ``Maximum Achievable Control Technology (MACT) Floor 
Analysis for Phosphate Rock Calciners at Phosphoric Acid Manufacturing 
Plants--Final Rule'' and ``Use of the Upper Prediction Limit for 
Calculating MACT Floors,'' which are available in the docket for

[[Page 50400]]

this action. Based on the available data, the existing phosphate rock 
calciners would be able to comply with this limit without installing 
additional Hg controls.
    We evaluated application of the BTF Hg limit for new phosphate rock 
calciners. Facilities would have time to plan for and consider the 
costs when determining whether to construct a new phosphate rock 
calciner. Additionally, sources may choose to only add one new calciner 
unit at a time, which would have considerably less impact than the 
costs associated with retrofitting all units at an existing site. 
Therefore, we evaluated the cost-effectiveness for installing Hg 
controls on a new phosphate rock calciner. Using the same cost data 
provided by the commenter, installing a single ACI would have capital 
costs of approximately $3,500,000. The annual cost ranges from 
approximately $720,000 (when a carbon injection rate of 5 lb/MMacf is 
used) to approximately $880,000 (when a carbon injection rate of 10 lb/
MMacf is used). This results in Hg reductions of 24 pounds of Hg per 
year for a single calciner unit, assuming the new phosphate rock 
calciner has similar emissions as the existing phosphate rock calciners 
at PCS Aurora. The resulting cost-effectiveness is estimated to be 
$29,800 to $36,400 per pound of Hg reduced, which we consider cost 
effective for new sources. This facility-level cost-effectiveness for 
Hg for new sources is comparable to values the EPA found to be cost 
effective for removal of Hg at the facility-level in other air toxics 
rules.\4\ Consequently, new phosphate-rock calciners must comply with 
the BTF Hg emission limit of 0.014 mg Hg/dscm at 3-percent 
O2.
---------------------------------------------------------------------------

    \4\ National Emission Standards for Hazardous Air Pollutants: 
Mercury Emissions from Mercury Cell Chlor-Alkali Plants (76 FR 
13852); National Emission Standards for Hazardous Air Pollutants: 
Coal- and Oil-Fired Electric Utility Steam Generating Units (76 FR 
24976 and 77 FR 9304); and National Emission Standards for Hazardous 
Air Pollutants: Gold Mine Ore Processing and Production Area Source 
Category (75 FR 22470).
---------------------------------------------------------------------------

    ii. HF Work Practices for Phosphate Rock Calciners--Comment. We 
received comment regarding HF work practices for phosphate rock 
calciners. One commenter supported the HF work practices and stated 
they are consistent with their current phosphate rock calciner 
operations. Another commenter does not support the implementation of HF 
work practices for phosphate rock calciners. This commenter, which is 
considering installation of a calciner in the future, noted that 
preliminary results indicate a calcination temperature of at least 
2,000 degrees Fahrenheit is necessary for their phosphate rock 
calciner. This commenter also explained they are evaluating a flash 
calciner, which operates with a much shorter retention time than the 
fluidized bed calciners currently in operation. The commenter argued 
that wet scrubbers should not be a requirement of the HF work practice 
because their phosphate rock calciner will be located in a remote area 
where treatment and disposal options for scrubber liquors may not be 
feasible. The commenter recommended the EPA allow for other control 
technologies with equivalent efficiencies.
    Another commenter does not support the use of work practices for 
HF, and declared the EPA should set numeric emission limits for HF from 
phosphate rock calciners. The commenter maintained that the EPA failed 
to satisfy the CAA section 112(h) test it must meet to promulgate work 
practice standards ``in lieu of'' numerical emission standards. The 
commenter stated that not using the available emissions data to set a 
floor limit is unlawful and arbitrary, even if the data are below the 
detection limit.
    Response. We are not adopting the proposed HF work practice 
standard for phosphate rock calciners in NESHAP subpart AA. Instead, we 
are adopting an emission limit for total fluoride from phosphate rock 
calciners. In proposing the HF work practices, we concluded that it was 
not feasible to prescribe or enforce an emission limit for HF due to 
limitations in the available EPA Method 320 HF test results (i.e., most 
of the emissions data were below the method detection limit). We now 
have concluded, based on analysis of public comments, that it is not 
feasible to accurately measure HF emissions from phosphoric acid 
manufacturing processes using EPA Method 320 (see section V.F.3.c of 
this preamble for further details). However, data are available to 
establish an emission limit for total fluoride from phosphate rock 
calciners. In 2015 only one facility operates phosphate rock calciners, 
which are controlled by a venturi-type scrubber. In response to the 
April 2010 CAA section 114 request, the facility provided EPA Method 
13B total fluoride emission testing results for one of their six 
identical phosphate rock calciners. We conclude that the total fluoride 
emission rate achieved by this phosphate rock calciner characterizes 
the emissions from all six calciners and thus this emission rate was 
used to determine the MACT floor for total F emissions. Therefore, for 
phosphate rock calciners, we are setting total F emission limits. We 
are also setting a work practice standard for periods of startup and 
shutdown in lieu of this numeric emission limit (see section V.E.3 of 
this preamble for further details). The use of total fluoride as a 
surrogate for the HAP HF is consistent with WPPA, SPA, and DAP/MAP 
process lines, which also have total fluoride emission limits in lieu 
of HF emission limits.
    For the Phosphoric Acid Manufacturing source category, we have a 
limited dataset for the pollutant total fluoride from phosphate rock 
calciners. Therefore, we evaluated this specific dataset to determine 
whether it is appropriate to make any modifications to the UPL approach 
used to calculate the MACT floor. For the phosphate rock calciner 
dataset, we performed the following steps: We selected the data 
distribution that best represents the dataset; ensured that the correct 
equation for the distribution was then applied to the data; and 
compared individual components of the limited dataset to determine if 
the total fluoride standard based on the limited dataset reasonably 
represents the performance of the units included in the dataset. The 
results of this analysis are presented below.
    The MACT floor dataset for total fluoride from new and existing 
phosphate rock calciners includes 3 test runs from 1 phosphate rock 
calciner. After determining that the dataset is best represented by a 
normal distribution and ensuring that we used the correct equation for 
the distribution, we considered the selection of a lower confidence 
level for determining the emission limit by evaluating whether the 
calculated limit reasonably represents the performance of the unit upon 
which it is based. In this case, the calculated emission limit is about 
twice the short-term average emissions from the best performing source, 
indicating that the emission limit is not unreasonable compared to the 
actual performance of the unit upon which the limit is based and is 
within the range that we see when we evaluate larger datasets using our 
MACT floor calculation procedures. Therefore, we determined that no 
changes to our standard UPL floor calculation procedure are warranted 
for this pollutant and subcategory. We are applying the same method of 
calculating a total fluoride limit as we did for the Hg MACT floor 
calculation, for which we gave notice in the preamble to the proposed 
rule. Additional details and background on the MACT floor calculation 
are provided in the memorandums, ``Maximum Achievable

[[Page 50401]]

Control Technology (MACT) Floor Analysis for Phosphate Rock Calciners 
at Phosphoric Acid Manufacturing Plants--Final Rule,'' ``Approach for 
Applying the Upper Prediction Limit to Limited Datasets,'' and ``Use of 
the Upper Prediction Limit for Calculating MACT Floors,'' which are 
available in the docket for this action. We also evaluated BTF options 
for total F, but were unable to identify any cost-effective BTF 
technologies. Table 3 of this preamble provides the results of the new 
and existing phosphate rock calciner MACT floor calculations 
(considering variability) for total F.

  Table 3--Results of the New and Existing MACT Floor Calculations for
     Total Fluoride From Phosphate Rock Calciners at Phosphoric Acid
                        Manufacturing Facilities
------------------------------------------------------------------------
            Pollutant                  Results              Units
------------------------------------------------------------------------
Total fluoride (for new and               9.0E-04   lb/ton of rock feed.
 existing sources).
------------------------------------------------------------------------

    b. Gypsum Dewatering Stack and Cooling Pond Work Practices--i. 
Ratio of Gypsum Dewatering Stack Area to Phosphoric Acid Manufacturing 
Capacity--Comment. Several commenters requested that the EPA either 
reconsider, withdraw, or eliminate the proposed gypsum dewatering stack 
area limitation of 80 acres per 100,000 tpy capacity (in equivalent 
P2O5 feed). Commenters claimed the use of flawed 
data and assumptions in the EPA's analysis in the following areas: (1) 
Ambiguous definitions of a ``gypsum dewatering stack,'' and ``new'' and 
``existing'' stacks; (2) inaccurate or outdated data on acreage of 
existing stacks and production capacity, stack closures, and plans for 
new stacks; (3) flawed or missing rationale and correlation between the 
gypsum dewatering stack area and phosphoric acid manufacturing 
capacity; (4) no technical or legal basis for the selection of the 80-
acre cutoff; (5) no consideration given to site-specific variables that 
influence the acreage of gypsum dewatering stacks; and (6) failure to 
consider impacts from closing an existing stack prior to commissioning 
a new stack.
    These commenters claimed the term ``gypsum dewatering stack'' is so 
broadly and ambiguously defined they are unable to determine the scope 
and impact of the proposed area limitation of 80 acres per 100,000 tpy 
capacity, or how the proposed limitation would be applied to 
facilities. They claimed the EPA's definition includes a wide array of 
features that have never before been considered part of the gypsum 
dewatering stack (e.g., pumps, piping, all collection and conveyance 
systems associated with gypsum to the stack and process wastewater 
return to the plant). Commenters argued that the EPA underestimated 
stack acreage used in the analysis and that the estimates should be 
much larger when the ``total system'' acreage is used. These commenters 
stated that using the ``total system'' acreage in the analysis 
demonstrates that the EPA significantly underestimated the number of 
acres at each facility that would need to be closed. One of these 
commenters asked whether a vertical expansion of an existing stack 
would be considered a ``new'' facility, and how the proposed work 
practice might be evaluated for compliance when surfaces of a 
``closed'' facility might be overlapped by an immediately-adjacent 
``new'' facility.
    Additionally, commenters argued that the EPA's technical rationale 
for limiting stack area was based on an arbitrary correlation with 
production capacity. One of these commenters said there is no 
relationship between gypsum dewatering stack area and phosphoric acid 
manufacturing capacity, and that outliers were removed from the 
analysis further confirming no quantitative relationship between stack 
area and facility capacity. This commenter also asserted that limiting 
the size of the gypsum dewatering stacks is not proven to limit HF 
emissions.
    Furthermore, two commenters claimed the 80-acre limit does not 
consider an evaluation of water balance and process water cooling needs 
for individual facilities. These commenters pointed out that a flat 
area does not require as large of a footprint for its gypsum dewatering 
stacks as compared to an area with large topographic relief. One of 
these commenters provided examples of two gypsum dewatering stacks 
located in mountainous areas that require larger footprints to 
construct ponds due to longer runs of pipe, roads, and dike.
    Finally, one commenter claimed that an updated acreage-based 
analysis would need to account for the transition period between a 
stack becoming ``inactive'' and the point in time of ``closure'' so as 
not to exceed the acreage limit while constructing a new stack. Another 
commenter stated that the startup of a gypsum dewatering stack is a 
lengthy process that may take more than a year, and that the ``ratio'' 
requirement inaccurately assumes simultaneous closure of an old stack 
with the opening (i.e., new construction) of a new stack. Another 
commenter also contended that construction and closure take years to 
complete and occur simultaneously, and that closing a gypsum dewatering 
stack before beginning construction on a new stack would require an 
entire companion production facility to be idled for an extended period 
and impose ``enormous direct and lost opportunity costs . . . such 
costs and plant idling are not justified.''
    Response. We agree with commenters that the proposed definition of 
``gypsum dewatering stack'' is too broad. As we stated in the preamble 
to the proposed rule, we intended the proposed ratio limit to apply to 
only the ``footprint acreage'' of the gypsum dewatering stacks, which 
was deliberately meant to exclude the areas where many supplementary 
processes (such as pumps, piping, ditches, drainage conveyances, water 
control structures, collection pools, cooling ponds, surge ponds, 
auxiliary holding ponds, and any other collection or conveyance system) 
are located. Therefore, we did not underestimate stack acreage used in 
the gypsum dewatering stack area limitation analysis, nor did we 
underestimate the number of acres at each facility that would need to 
be closed. However, in an effort to clarify the specific emission 
source that we are regulating in the final rule (NESHAP subpart AA), we 
have included a new term, ``gypsum dewatering stack system,'' and 
revised the definition of ``gypsum dewatering stack'' in the final 
rule. We are finalizing ``gypsum dewatering stack system'' to mean 
``the gypsum dewatering stack, together with all pumps, piping, 
ditches, drainage conveyances, water control structures, collection 
pools, cooling ponds, surge ponds, auxiliary holding ponds, regional 
holding ponds and any other collection or conveyance system associated 
with the transport of gypsum from the plant to the gypsum dewatering 
stack, its management at the

[[Page 50402]]

gypsum dewatering stack, and the process wastewater return to the 
phosphoric acid production or other process.'' We are finalizing 
``gypsum dewatering stack'' to mean ``any defined geographic area 
associated with a phosphoric acid manufacturing plant in which gypsum 
is disposed of or stored, other than within a fully enclosed building, 
container, or tank.'' This revised definition of ``gypsum dewatering 
stack'' is based on Florida Administrative Rule 62-273.200 which 
regulates phosphogypsum management, and clearly includes any gypsum 
disposal pile, as well as the associated gypsum pond (which is also 
known as a settling pond, used to deposit the gypsum slurry, and is 
often located in the middle of the gypsum disposal pile), but does not 
include separate cooling ponds (for which we have retained the proposed 
definition of ``cooling pond'' in the NESHAP subpart AA final rule).
    Nevertheless, in light of other concerns raised by commenters, we 
are not adopting the proposed work practice that limits the size of 
active gypsum dewatering stacks, which would have been applicable to 
facilities when new gypsum dewatering stacks are constructed.
    As we stated in the preamble to the proposed rule, we did not 
detect a correlation between gypsum stack dewatering area and 
phosphoric acid manufacturing capacity; however, we proposed the size 
limit because we believe that reducing the gypsum dewatering stack area 
is directly related to reducing HF emissions. We also believed that 
phosphoric acid manufacturing capacity was related to the size of 
gypsum dewatering stacks and that it was operationally appropriate to 
allow large facilities to build larger gypsum dewatering stacks, while 
limiting smaller facilities to building a proportionally smaller gypsum 
dewatering stack. However, we have now concluded, based on analysis of 
public comments and other supplemental information provided, that it is 
not feasible to require facilities to close gypsum dewatering stacks 
based on a ratio of total active gypsum dewatering stack area (i.e., 
sum of the footprint acreage of all active gypsum dewatering stacks 
combined) to annual phosphoric acid manufacturing capacity. As 
commenters stated, the gypsum dewatering stack acreage does not relate 
to production capacity and, importantly, gypsum dewatering stack 
development must be considered in light of the operations of the entire 
facility. Factors that affect the size and development of gypsum 
dewatering stacks include: (1) The availability and topography of land 
near the facility; (2) facilities generate a substantial amount of 
gypsum waste in the phosphoric acid manufacturing process; (3) managing 
the gypsum waste that is generated is an important operating principle 
for all facilities (regardless of phosphoric acid production capacity); 
and (4) limiting the gypsum dewatering stack acreage or changing the 
way facilities build gypsum dewatering stacks could have a detrimental 
impact on a facility's operations. Additionally, we agree with 
commenters that closure of a gypsum dewatering stack does not happen 
immediately, but rather requires a transitional period that can take 
years to complete. During this transitional period, a new stack is 
begun, but it may be years before it is fully operational and can 
receive all gypsum and slurry from the facility. This transitional 
period would make it difficult, if not impossible, for a facility to 
comply with the proposed work practice that limits the size of active 
gypsum dewatering stacks because the proposed size limit assumed 
immediate closure. Since closure does not happen immediately, and there 
is no correlation between dewatering stack acreage and phosphoric acid 
production, we are not adopting the proposed work practice that limits 
the size of active gypsum dewatering stacks.
    We are removing the definition of ``closed gypsum dewatering 
stack,'' and revising the definition of ``active gypsum dewatering 
stack,'' as well as the definitions for when a gypsum dewatering stack 
is considered ``new'' or ``existing'' (see sections V.C.3.b.ii and 
V.C.3.b.iii of this preamble for further details).
    ii. Necessity or Justification of Work Practice Standards for 
Fugitive HF Emissions--Comment. Numerous commenters claimed that there 
is insufficient technical analysis as to the feasibility and 
effectiveness of the control techniques that were proposed as options 
(as part of a work practice standard in the form of a management plan) 
for controlling fugitive HF emissions from gypsum dewatering stacks and 
cooling ponds. One of these commenters supported the EPA's claim that 
emissions from gypsum dewatering stacks and cooling ponds would 
inherently constitute fugitive emissions, and that conceptually, a work 
practice standard is a reasonable approach to emissions control; 
however, they challenged the technical basis for the specific control 
techniques listed in the proposed management plan. Commenters contended 
that the proposed control techniques have not been demonstrated to have 
an effect on fugitive HF emissions, and stated the EPA did not quantify 
the expected reductions in HF emissions resulting from the proposed 
work practice standard for gypsum dewatering stacks and cooling ponds. 
A commenter noted that some of the control techniques were derived from 
their facility's title V permit and that the EPA needed to recognize 
that (a) it is not clear (with a couple of exceptions) that these 
control techniques provide any significant emission reductions; (b) 
recent information may not support these control techniques providing 
emission reductions; and (c) there is considerable uncertainty in the 
emissions associated with cooling ponds and gypsum dewatering stacks. 
Another commenter argued that the EPA must justify the control 
techniques and show that they are not only technically effective, but 
also cost-effective and achievable within the industry. Commenters 
asserted that only two sources of information were used by the EPA in 
its determination of the control techniques that were proposed as 
options for controlling fugitive HF emissions in the proposed gypsum 
dewatering stack and cooling pond management plan. Commenters also 
noted that there is a large amount of uncertainty related to which 
specific control techniques are feasible and effective in reducing 
fugitive HF emissions. The following paragraphs provide a summary of 
the comments that the Agency received on each specific control 
technique.
    Three commenters opposed the use of submerged discharge pipes and 
siphon breaks below the surface of the cooling pond as a fugitive HF 
emissions control technique. They claimed that submerging cooling pond 
discharge lines for above-grade ponds would create a significant risk 
for a siphon effect to occur when a pumping system is shutdown, causing 
backpressure on the pump seals back down the line, and, thus, defeating 
the purpose of the siphon break. One of these commenters added that 
submerging siphon breaks will impede the ability of these devices to 
prevent backflow because submersion may interfere with the atmospheric 
connection needed to make siphon breaks operate properly.
    One commenter stated that although they use a rim ditch (cell) 
building technique, it is not an appropriate work practice for reducing 
HF emissions, and mentioned that the EPA does not provide data or an 
explanation of the linkage between minimizing the gypsum dewatering 
stack surface area and reducing emissions. This commenter suggested 
that the EPA define the technique as ``a gypsum stack building

[[Page 50403]]

technique where gypsum slurry is deposited along the stack perimeter 
with flow directed along a ditch before the liquid flow is conveyed to 
the settling compartments.'' Another commenter stated that minimizing 
the gypsum pond surface areas is not feasible in Florida, North 
Carolina, and Louisiana because gypsum pond surface areas are optimized 
to provide annual evaporative water losses necessary to maintain zero 
water discharge.
    Several commenters also objected to the wetting of the active 
gypsum dewatering stack as a fugitive HF emissions control technique 
because the technique may be infeasible and counter-productive due to 
water balance issues at nearly every affected facility. One commenter 
argued that applying fresh water is not feasible (i.e., water trucks 
are not feasible or safe; irrigation in the West is not feasible; pipes 
are at risk of freezing) and another commenter stated that using 
recycled water may actually increase fugitive emissions because HF 
resides primarily in residual and make-up waters used to transport the 
gypsum slurry to the gypsum dewatering stack. One commenter contended 
that determining hot or dry periods is too subjective; therefore, it 
would be difficult to know when the control technique would apply. 
Another commenter illustrated the uncertainty of wetting of the active 
gypsum dewatering stack as a fugitive HF emissions control technique by 
identifying two studies with contradicting conclusions (one concluded 
that most HF is emitted from aqueous surfaces and trends with solar 
radiation, and the other study concluded that drying gypsum is a major 
source of ambient fluoride emissions from gypsum storage areas).
    One commenter challenged the EPA's lack of evidence on the 
effectiveness of applying slaked lime to gypsum dewatering stacks as a 
fugitive HF emissions control technique, and claimed that it would not 
be feasible, referring to rain as threat to eliminate the potential for 
effectiveness. On the contrary, another commenter described how they 
apply a lime solution on top of reachable drying gypsum stack areas, 
and that the reaction of fluoride with slaked lime does result in the 
``tie-up'' of volatile F, although they are not aware of any studies 
that have measured or quantified reductions.
    In addition, commenters also claimed that enormous costs would be 
associated with the fugitive HF emissions control technique requiring 
facilities to apply soil caps and vegetation to all side slopes of the 
active gypsum dewatering stack up to 50 feet below the stack top. Some 
of these commenters mentioned that there are state rules that require 
soil caps and side vegetation on side slopes for erosion/water impact 
control, but not for the purpose of fugitive HF emissions control.
    Furthermore, commenters requested that the closure of a gypsum 
dewatering stack not be considered a fugitive HF emissions control 
technique. One commenter contended that the EPA should allow the final 
cover on a closed stack to consist of a synthetic liner, as this would 
achieve the same purpose as a vegetative liner and may be more 
appropriate in some instances. Another commenter explained that some 
states and the EPA have closure requirements under Resource 
Conservation and Recovery Act (RCRA), including, for example, 
requirements for long term care practices (beyond 20-50 years); shaping 
and configuration of gypsum dewatering stacks; site security. They 
suggested that due to these detailed requirements, it would be best to 
defer to stack closure requirements within other regulations and not 
have NESHAP requirements that involve or require stack closure.
    Finally, commenters requested that if the EPA proceeds with a final 
rule that includes work practices for reducing fugitive HF emissions 
from gypsum dewatering stacks or cooling ponds, the work practices 
should include a flexibility mechanism for facilities to use additional 
practices not codified during this rulemaking. One commenter asserted 
that work practice standards that might commonly be practicable for 
other industries are not universally practicable (or legally 
permissible) throughout the phosphoric acid and phosphate fertilizer 
industries, and some practices might be appropriate for some 
facilities, but not others (depending on location, climate, etc.).
    Response. We are adopting the proposed work practice standard that 
requires owners or operators to prepare, and operate in accordance with 
a gypsum dewatering stack and cooling pond management plan; however, 
based on analysis of public comments, we are making some changes to the 
specific control measures that we proposed as options in the plan for 
controlling fugitive HF emissions. In the final rule, the Agency is 
using the terminology ``control measures'' in lieu of the proposed 
terminology ``control techniques'' because it more accurately describes 
the list of options in the rule and avoids confusion with other CAA 
programs. We are finalizing standards that will reduce HAP emissions 
from gypsum dewatering stacks and cooling ponds because, as explained 
in the preamble to the proposed rule, the 1999 Phosphoric Acid 
Manufacturing NESHAP (i.e., NESHAP subpart AA) did not regulate 
fugitive HF emissions from gypsum dewatering stacks or cooling ponds. 
As explained in the preamble to the proposed rule, we are adopting a 
work practice standard instead of numeric emission limits because it is 
``not feasible to prescribe or enforce an emission standard'' for these 
emissions because they ``cannot be emitted through a conveyance 
designed and constructed to emit or capture such pollutant'' (see CAA 
section 112(h)(2)(A)) as the several hundred acres average size of 
these emission sources makes conveyance impractical. The size of these 
emission sources also makes it difficult to quantify the emission 
reductions that any control measure employed will achieve. However, in 
the paragraphs below, we explain how each control measure is feasible 
and effective in reducing fugitive HF emissions. We also provide 
details on the changes we have made to the gypsum dewatering stack and 
cooling pond management plan since proposal. Even after these changes, 
the measures are consistent with CAA section 112(d) controls and 
reflect a level of performance analogous to a MACT floor.
    We noted in the preamble to the proposed rule that we believe that 
it is most effective for sources to determine the best practices that 
are to be incorporated into their site-specific gypsum dewatering stack 
and cooling pond management plan. We also stated in the preamble to the 
proposed rule that sources would be required to incorporate control 
measures from the list of options being proposed, and we solicited 
comment on the proposed site-specific gypsum dewatering stack and 
cooling pond management plan. In addition, we made considerable effort 
\5\ before and after proposal in identifying a list of control measure 
options that encompass enough variety that at least one control measure 
option is feasible for at least one of each facility's existing gypsum 
dewatering stacks and/or cooling ponds. In fact, we are not aware

[[Page 50404]]

of any facility that does not use a rim ditch (cell) building 
technique. Therefore, we disagree with commenters that the options we 
have listed for the gypsum dewatering stack and cooling pond management 
plan are not technically feasible.
---------------------------------------------------------------------------

    \5\ See the following documents which are all available in 
Docket ID No. EPA-HQ-OAR-2012-0522): ``USEPA Meeting with The 
Fertilizer Institute, July 24, 2013''; ``TFI meeting with USEPA to 
discuss RTR for Phosphoric Acid and Phosphate Fertilizer NESHAPs, 
September 11, 2014''; ``EPA Meeting Minutes for TFI Discussion March 
12, 2015''; ``Summary of Potential Costs for Implementing Phosphate 
NESHAPs/Recommendations for Phosphogypsum Stack Work Practices, May 
5, 2015''; ``Notes from Meeting with Florida DEP Regarding Gypsum 
Dewatering Stack and Cooling Pond Management Plan, March 4, 2015''; 
and ``Site Visits to Mosaic Plant City and Mosaic New Wales, March 
4, 2015.''
---------------------------------------------------------------------------

    Additionally, personnel from the Florida Department of 
Environmental Protection (DEP) had concerns regarding how the plan 
would be implemented, as well as how a facility would show compliance 
with the control measure it chooses (see ``Notes from Meeting with 
Florida DEP Regarding Gypsum Dewatering Stack and Cooling Pond 
Management Plan, March 4, 2015,'' which is available in Docket ID No. 
EPA-HQ-OAR-2012-0522). Therefore, in an effort to improve compliance 
demonstration with a facility's site-specific gypsum dewatering stack 
and cooling pond management plan, we are including a condition in the 
final NESHAP subpart AA rule that requires facilities to submit their 
plan for approval to the Administrator. Facilities will be required to 
provide details on how they plan to implement and show compliance with 
the control measure(s) that they choose. The Administrator will approve 
or disapprove the facility's site-specific gypsum dewatering stack and 
cooling pond management plan within 90 days after it is received. There 
may be a benefit to facilities and permitting authorities for the 
gypsum dewatering stack and cooling pond management plan and the title 
V major modification application to be submitted and reviewed at the 
same time. To change any of the information submitted in the plan, the 
facility must submit a revised plan 60 days before the change is to be 
implemented in order to allow time for review and approval by the 
Administrator before the change is implemented.
    We are not including an option in the NESHAP subpart AA final rule, 
as commenters requested, that would provide a flexibility mechanism for 
facilities to use additional practices not codified during this 
rulemaking. This type of flexibility does not provide regulatory 
certainty that is needed for both industry and the EPA.
    Although some commenters opposed using a submerged discharge pipe 
(with necessary siphon breaks to a level below the surface of the pond) 
as a fugitive HF emissions control measure, we believe submerging a 
discharge pipe can be appropriate and effective for reducing emissions 
from process water discharges into a cooling pond, although some 
facilities may not choose this option. Moreover, we agree with 
commenters that submerging siphon breaks could impede the ability of 
these devices to prevent backflow; therefore, we are removing this 
requirement from the final rule. On a recent site visit (see ``Site 
Visits to Mosaic Plant City and Mosaic New Wales, March 4, 2015,'' 
which is available in Docket ID No. EPA-HQ-OAR-2012-0522), we noted 
strong vapor odors coming from splash operations occurring at a non-
submerged pipe that was discharging process water into a cooling pond. 
According to AP-42, Chapter 5.2--Transportation and Marketing of 
Petroleum Liquids (01/95), significant turbulence and vapor/liquid 
contact that occur during splash discharge operations will result in 
higher levels of vapor generation and emissions loss compared to using 
a submerged discharge operation. Liquid turbulence is controlled 
significantly during submerged discharge operations, resulting in much 
lower vapor generation than encountered during splash discharge 
operations. We believe this demonstrates that submerging the pipe is an 
effective technique for mitigating HF emissions, and we are therefore 
retaining this option for cooling ponds.
    However, we are removing the option of submerging a discharge pipe 
that is associated with the gypsum pond because it is not a feasible 
option due to high solids volume in the slurry. (A gypsum pond, also 
called a settling pond, often is located in the middle of a gypsum 
disposal pile and receives waste gypsum slurry.) Based on information 
received from industry after the public comment period ended for the 
proposal (see Docket ID No. EPA-HQ-OAR-2012-0522-0048), it is much more 
likely for this particular pipe to become clogged, creating 
backpressure on pump seals. Submerging the discharge pipe under water 
in the gypsum pond creates a potential restriction against the 
discharging slurry that could get worse as solids build up around and 
against the end of the pipe. The discharge pipe for the gypsum pond is 
also routinely moved, which complicates submersing it.
    As we stated earlier in our response, we are not aware of any 
facility that uses a gypsum dewatering stack building technique that is 
different from rim ditch (cell) building. With regard to commenters' 
assertions that the EPA did not provide data or explain the link 
between minimizing the gypsum dewatering stack surface area and 
reducing fugitive HF emissions, we believe that using the rim ditch 
technique over the lifespan of a gypsum dewatering stack will reduce 
the surface area of the gypsum pond and thereby reduce fugitive HF 
emissions. Fugitive HF emissions are calculated using an emission 
factor that is directly related to the total acreage from the gypsum 
dewatering stack, which includes the pond surface area (tons HF per 
acre per year); therefore, minimizing the pond surface area would 
minimize HF emissions. The rim ditch (cell) building technique is 
mainly used for gypsum dewatering stack stability since inner and outer 
dikes are used to create a rim ditch that provides better protection 
against overflow of the gypsum pond. However, as rim ditches are filled 
with slurry, the gypsum pond area will gradually decrease within each 
cell, thereby shrinking the amount of surface area of the pond that is 
exposed to the atmosphere (reducing the amount of fugitive HF 
emissions). An alternative to the rim ditch technique is to simply 
discharge gypsum slurry into the gypsum pond. With this technique, 
there is no inner dike to control slurry flow and the pond surface area 
would not be reduced as quickly or consistently. This increased surface 
area would allow greater potential for fugitive HF emissions due to the 
larger amount of surface water exposed to the atmosphere. We are 
revising this control measure option in the NESHAP subpart AA final 
rule to clarify that owners or operators must minimize the surface area 
of the gypsum pond associated with the active gypsum dewatering stack 
(and not the surface area of the active gypsum dewatering stack as we 
had proposed) by using a rim ditch (cell) building technique or other 
building technique. This clarification also addresses industry's 
suggestion to reword the control measure in response to a meeting that 
occurred after the public comment period closed (see ``EPA Meeting 
Minutes for TFI Discussion March 12, 2015,'' and ``Summary of Potential 
Costs for Implementing Phosphate NESHAPs/Recommendations for 
Phosphogypsum Stack Work Practices, May 5, 2015,'' which are both 
available in Docket ID No. EPA-HQ-OAR-2012-0522). Moreover, in this 
same correspondence that occurred after the public comment period 
closed, industry provided a suggestion for the definition of ``rim 
ditch.'' We agree with industry's suggested definition; however, we 
believe the definition more appropriately covers the meaning of ``rim 
ditch (cell) building technique'' and not just ``rim ditch.'' We are 
including this definition in the final rule for ``rim ditch (cell) 
building technique'' in an effort to clarify what we mean by this 
control measure. The

[[Page 50405]]

final rule defines ``rim ditch (cell) building technique'' as a gypsum 
dewatering stack construction technique that utilizes inner and outer 
dikes to direct gypsum slurry flow around the perimeter of the stack 
before directing the flow and allowing settling of finer materials into 
the settling compartment. For the purpose of this definition, the rim 
ditch (cell) building technique includes the compartment startup phase 
when gypsum is deposited directly into the settling compartment in 
preparation for ditch construction, as well as the step-in or terminal 
phases when most solids must be directed to the settling compartment 
prior to stack closure. Decant return ditches are not rim ditches.
    Based on commenters' objection to wetting active gypsum dewatering 
stacks as a fugitive HF emissions control measure, and additional 
discussion with industry (see ``EPA Meeting Minutes for Simplot 
Discussion April 1, 2015,'' which is available in Docket ID No. EPA-HQ-
OAR-2012-0522), we determined that the proposed rule was not clear on 
how this control measure would be used. This control measure is not 
applied to the side slopes of the gypsum dewatering stacks, and instead 
is used on certain gypsum areas within cells of a gypsum dewatering 
stack. According to one facility located in arid climate (see ``EPA 
Meeting Minutes for Simplot Discussion April 1, 2015,'' which is 
available in Docket ID No. EPA-HQ-OAR-2012-0522), these areas may be 
more susceptible to drying out in warmer months due to higher surface 
temperatures of the gypsum dewatering stack; therefore, a system of 
weirs can be used to help direct gypsum pond water (not fresh water) to 
these areas to keep them wet. We agree with the commenter who pointed 
out that that applying water to a gypsum stack may actually increase 
fugitive emissions because HF resides primarily in the water used to 
transport the gypsum slurry to the gypsum dewatering stack. We realize 
that this option might increase the surface area of the gypsum pond 
water which conflicts with our understanding that minimizing surface 
area of the gypsum pond will minimize HF emissions. Therefore, we are 
not adopting this proposed control measure in the NESHAP subpart AA 
final rule.
    In response to a commenter's assertion that there is lack of 
evidence of the effectiveness of applying slaked lime to gypsum 
dewatering stacks as a fugitive HF emissions control measure, we 
received information after the public comment period ended (see Docket 
ID No. EPA-HQ-OAR-2012-0522-0048) that at least one facility uses this 
technique to help meet its state ambient air standard for F. This 
commenter stated that, based on data from their site-specific ambient 
air monitoring, they apply a lime solution to their gypsum dewatering 
stack areas during periods where they are close to violating their 30-
day state ambient air standard for F, measured as HF, in order to stay 
below the standard. Slaked lime can precipitate fluorides from gypsum 
dewatering stacks and cooling ponds, thus reducing the availability of 
fluorides in solution that could then be released into the air during 
evaporation. This is an example of the type of detail that the 
Administrator may require be included in the facility's site-specific 
plan (in addition to how compliance would be demonstrated) before it 
could be approved. We have clarified in the final rule that if this 
control measure is chosen, then the plan must include the method used 
to determine the specific locations slaked lime is applied. The plan 
must also include the methods used to determine the quantity of, and 
when to apply, slaked lime (e.g., slaked lime may be applied to achieve 
a state ambient air standard for F, measured as HF).
    With respect to the measure involving application of soil caps and 
vegetation to side slopes of a gypsum dewatering stack, on recent site, 
visits personnel from Mosaic and the Florida DEP had concerns that this 
control measure was too specific in that it could be difficult for 
facilities to demonstrate compliance with the ``50 feet below the stack 
top'' requirement as well as the requirement to apply soil caps and 
vegetation to all side slopes (see ``Site Visits to Mosaic Plant City 
and Mosaic New Wales, March 4, 2015,'' and ``Notes from Meeting with 
Florida DEP Regarding Gypsum Dewatering Stack and Cooling Pond 
Management Plan, March 4, 2015,'' which are available in Docket ID No. 
EPA-HQ-OAR-2012-0522). We recognize that applying soil caps and 
vegetation to side slopes of a gypsum dewatering stack is an ongoing 
process that continuously changes over time based on facility-specific 
operations. Therefore, we have revised this control measure option in 
the NESHAP subpart AA final rule to acknowledge that this technique 
will only be applied to portions of the side slopes that are no longer 
active on a gypsum dewatering stack instead of all side slopes up to 50 
feet below the top of the gypsum dewatering stack. We also have revised 
this option to allow the use of a synthetic cover in lieu of soil caps 
and vegetation. Furthermore, we expect that if a facility chose to use 
this specific control measure in their plan, the Administrator may 
require details on schedule, and how the portion of side slopes that 
received soil caps and vegetation, or a synthetic cover, is determined 
(in addition to how compliance would be demonstrated), before the plan 
could be approved. Therefore, we have clarified in the final rule that 
the plan must include the method used to determine the specific 
locations of soil caps and vegetation, or synthetic cover, and specify 
the acreage and locations where soil caps and vegetation, or synthetic 
cover, is applied. The plan must also include a schedule describing 
when soil caps and vegetation, or synthetic cover, is to be applied.
    Additionally, we believe that this control measure creates a 
barrier on the surface of the gypsum dewatering stack side slopes that 
reduces HF emissions; therefore, we disagree with commenters' assertion 
that applying soil caps and vegetation may not be an effective option 
for fugitive HF emissions control. The Florida DEP has used this 
control measure as part of its overall management of fluorides from 
gypsum dewatering stacks; and Wyoming has approved this control measure 
in a facility's title V permit as an optional method for reducing 
fugitive fluoride emissions. We also disagree with a request \6\ to 
reword this control measure to require a gypsum dewatering stack 
construction and operation plan because the commenter did not provide 
any justification on how this activity reduces fugitive HF emissions 
from gypsum dewatering stacks.
---------------------------------------------------------------------------

    \6\ See ``EPA Meeting Minutes for TFI Discussion March 12, 
2015,'' and ``Summary of Potential Costs for Implementing Phosphate 
NESHAPs/Recommendations for Phosphogypsum Stack Work Practices, May 
5, 2015,'' which are both available in Docket ID No. EPA-HQ-OAR-
2012-0522.
---------------------------------------------------------------------------

    We disagree with commenters' requests to exclude closure from the 
list of measures for controlling fugitive HF emissions from gypsum 
dewatering stacks. We believe that closing a gypsum dewatering stack is 
one of the best solutions for reducing fugitive HF emissions because it 
permanently reduces the emissions from the greatest contributing 
source. However, we are revising this control measure option in the 
NESHAP subpart AA final rule to allow a facility to design its own 
closure requirement plan, provided that the closure requirements, at a 
minimum, contain: (1) A specific trigger mechanism for when owners or 
operators must begin the closure process on the gypsum dewatering 
stack, and (2) a requirement to install a final cover. As with all 
gypsum dewatering stack and

[[Page 50406]]

cooling pond management plans, this closure requirement must be 
submitted to the Agency for approval. Although we are not identifying a 
specific trigger mechanism in the final rule, one example of a trigger 
mechanism is a facility-specified length of time where the gypsum 
dewatering stack is inactive and no longer receives gypsum (i.e., once 
the gypsum dewatering stack stops receiving gypsum for a period of 
time, the facility must begin closing it). Also, we are clarifying that 
a final cover means the materials used to cover the top and sides of a 
gypsum dewatering stack upon closure. This addresses commenters request 
that the EPA should allow the final cover on a closed stack to consist 
of a synthetic liner. Finally, in light of our decision to revise the 
control measure option for closing a gypsum dewatering stack, we are 
also removing the definition of a ``closed gypsum dewatering stack'' 
from the NESHAP subpart AA final rule. Since the revised language 
relies on a specific trigger mechanism for when owners or operators 
must begin the closure process on the gypsum dewatering stack, the 
definition of a ``closed gypsum dewatering stack'' is no longer 
necessary in the final rule. Because we are removing the definition of 
a ``closed gypsum dewatering stack'' from the final rule, we are 
revising the definition of an ``active gypsum dewatering stack.'' In 
the NESHAP subpart AA final rule, an ``active gypsum dewatering stack'' 
means a gypsum dewatering stack that is currently receiving gypsum, 
received gypsum within the last year, or is part of the facility's 
water management system. A gypsum dewatering stack that is considered 
closed by a state authority is not considered an active gypsum 
dewatering stack.
    As we have stated before, the final list of NESHAP subpart AA 
control measures is exhaustive enough that a facility has a number of 
options for selecting a control measure that would be feasible for 
their particular operations. We assume that facilities would choose the 
lowest cost option, and that all facilities are using at least one of 
the control measure options already (e.g., we are not aware of any 
facilities that do not use a rim ditch (cell) building technique). 
Therefore, we disagree with the commenters' claim that enormous costs 
would be incurred if they were required to apply soil caps and 
vegetation to all side slopes of the active gypsum dewatering stack up 
to 50 feet below the stack top. We are not requiring that facilities 
implement this control measure since this specific control technique is 
not a requirement, but instead an option for how a facility may 
demonstrate compliance with the work practice standards for fugitive HF 
emissions from the gypsum management system.
    iii. Requirement to Use At Least Two of the Fugitive HF Emissions 
Control Measures--Comment. One commenter requested that the EPA 
eliminate the ``dual practice'' approach for new sources. Two 
commenters declared that the requirement to implement ``at least two of 
the control techniques'' listed for ``each regulated gypsum dewatering 
stack and cooling pond'' is not possible without a broader list that 
includes at least two practices for cooling ponds. Additionally, with 
regard to closing an active gypsum dewatering stack as a control 
technique option, the commenter contended that giving an owner of a new 
gypsum dewatering stack the option of closing it in tandem with a 
mandatory second control technique is ``nonsensical'' because the ``new 
stack would immediately have to be closed to implement the practice.'' 
Another commenter wanted clarification as to whether the lateral 
expansion of an existing gypsum dewatering stack is considered a new 
stack, and thus would trigger the proposed work practice standards 
related to the size of active gypsum dewatering stacks and production 
ratio. The commenter also sought clarification as to whether at least 
two of the control techniques be used in the gypsum dewatering stack 
and cooling pond management plan for controlling fugitive HF emissions 
would be required.
    Response. We agree with the commenter that the proposed requirement 
for new gypsum dewatering stacks and cooling ponds to implement ``at 
least two of the control techniques'' listed for ``each'' regulated 
``gypsum dewatering stack and cooling pond,'' would make compliance for 
cooling ponds impossible for new sources without a broader list with at 
least two control measures for cooling ponds. In the final rule, the 
Agency is using the terminology ``control measures'' in lieu of the 
proposed terminology ``control techniques'' because it more accurately 
describes the list of options in the rule and avoids confusion with 
other CAA programs. As stated in a previous response, in an effort to 
clarify the specific emission source that we are regulating in the 
final rule (NESHAP subpart AA), we have included a new term, ``gypsum 
dewatering stack system,'' (see sections V.C.3.b.i of this preamble for 
further details) in the final rule. This revision also clarifies our 
original intent that the two control measure options that a facility 
selects can be for any combination of gypsum dewatering stacks and/or 
cooling ponds in the gypsum dewatering stack system. For example, if a 
facility operates a cooling pond considered a new source, the facility 
may choose to not implement the control measure option requiring a 
submerged discharge pipe for the new cooling pond, and instead 
implement two control measures at one or more gypsum dewatering stacks 
no matter whether they be considered a new or existing source. 
Furthermore, we have revised the control measure option for closing a 
gypsum dewatering stack (see section V.C.3.b.ii of this preamble for 
further details). Because of this change to the NESHAP subpart AA final 
rule, there is no longer a requirement to immediately close the active 
gypsum dewatering stack in tandem with a mandatory second control 
measure option.
    Lastly, the Agency has revised the definitions in the NESHAP 
subpart AA final rule for when a gypsum dewatering stack is considered 
``new'' or ``existing'' in order to address whether a lateral expansion 
of an existing gypsum dewatering stack is considered a new gypsum 
dewatering stack. The revised definitions in the final rule also deal 
with a concern one commenter raised during the comment period about 
triggering the proposed regulation for a ``new'' source each time they 
rotate the functionality of their three gypsum dewatering stack sites 
at their facility (this topic was also discussed after the comment 
period closed, see ``USEPA Meeting Minutes for PCS Aurora Discussion 
(2.2.2015),'' which is available in Docket ID No. EPA-HQ-OAR-2012-
0522). We are revising the NESHAP subpart AA final rule such that a 
gypsum dewatering stack or cooling pond is considered ``new'' if it 
meets two criteria: (1) It was constructed or reconstructed after 
August 19, 2015, and (2) it was required to obtain a permit by a state 
authority for the construction or reconstruction. Some lateral 
expansions may build beyond a facility's existing permitted capacity 
(and design dimensions of the gypsum dewatering stack); therefore, 
these lateral expansions would be considered ``new'' in the final rule 
because the facility would be required to obtain (or revise) their 
existing permitted capacity (and design dimensions). Because of this 
change in the NESHAP subpart AA final rule, we are also revising the 
criteria for when a gypsum dewatering stack or cooling pond is 
considered ``existing.'' Specifically, a gypsum dewatering stack or 
cooling pond is

[[Page 50407]]

considered ``existing'' if it meets one of two criteria: (1) It was 
constructed or reconstructed on or before August 19, 2015, or (2) it 
was constructed or reconstructed after August 19, 2015 and it was not 
required to obtain a permit by a state authority for the construction 
or reconstruction.
    iv. Fugitive HF Emissions Control Measure Considerations for 
Cooling Ponds--Comment. One commenter referenced a 1978 EPA document: 
``Evaluation of Emissions and Control Techniques for Reducing Fluoride 
Emissions from Gypsum Ponds in the Phosphoric Acid Industry'' and 
questioned why the EPA proposed work practice standards focused solely 
on gypsum dewatering stacks, while the EPA has in the past studied and 
documented more work practices for controls of cooling pond emissions, 
which are not discussed as alternatives to the proposed rule. Another 
commenter requested that if EPA keeps cooling ponds as part of the 
gypsum dewatering stack and cooling pond management plan, then EPA 
should provide more than one work practice that could be implemented at 
a cooling pond. They suggested that EPA add a control measure option 
(for cooling ponds) that would require developing a plan to optimize 
the size of cooling ponds to address fugitive HF emissions (as 
appropriate based on the conditions at the facility).
    In addition, another commenter suggested additional control measure 
options for reducing fugitive HF emissions from cooling ponds. This 
commenter suggested EPA include an option to develop and implement a 
plan for dredging cooling ponds which helps maintain cooling capacity, 
and, therefore, can reduce fugitive emissions by reducing the vapor 
pressure of fluoride in the pond water. This commenter also suggested 
EPA include an option to implement a system for the recovery of 
fluoride for water that is directed to cooling ponds. The commenter 
pointed out that one of its facilities has the capability to recover 
fluoride as hydrofluorosilicic acid during the phosphoric acid 
evaporation process. The commenter stated that this recovery process is 
operated as needed to meet the market demand for hydrofluorosilicic 
acid. Finally, the commenter suggested EPA include an option to 
implement a system for the removal of fluoride for water that is 
directed to cooling ponds (for example, by adding lime to increase the 
pH).
    Response. We are aware of the 1978 EPA document, ``Evaluation of 
Emissions and Control Techniques for Reducing Fluoride Emissions from 
Gypsum Ponds in the Phosphoric Acid Industry,'' and the six potential 
control techniques it examines for reducing fluoride emissions from 
gypsum ponds. These six potential control techniques include: (1) Use 
of the ``Kidde'' process; (2) use of the ``Swift'' process; (3) use of 
lime to raise pH; (4) dry conveyance of gypsum, (5) pretreatment of ore 
by calcining; and (6) changing the entire phosphoric acid production 
process to a ``hemi/dehydrate'' process. The 1978 EPA document 
clarifies that the first four of these potential control techniques 
could also reduce fluoride emissions from cooling ponds. The ``Swift,'' 
``Kidde,'' and ``hemi/dehydrate'' processes each use byproduct fluoride 
in the WPPA to produce hydrofluorosilicic acid (an acid generally used 
in fluoridation of drinking water, but also has other industry uses) or 
ammonium silicofluoride. We are aware of at least two facilities that 
are equipped and capable of making hydrofluorosilicic acid; however, it 
is not clear which process they use, nor is it clear if either facility 
is actively making hydrofluorosilicic acid. However, facilities have 
expressed that production of hydrofluorosilicic acid for the primary 
purpose of controlling HF emissions is not practical. Facilities that 
produce hydrofluorosilicic acid seek to sell the product for use in 
water fluoridation.\7\ In fact, one commenter stated that their 
recovery process is operated as needed to meet the market demand for 
hydrofluorosilicic acid. Facilities would not produce this product in 
the absence of a market demand, as the hydrofluorosilicic acid would be 
another waste stream that would need to be disposed of. Therefore, we 
do not believe this to be a reasonable control technique option for 
fugitive HF emissions from these sources.
---------------------------------------------------------------------------

    \7\ http://www.cdc.gov/fluoridation/factsheets/engineering/wfadditives.htm.
---------------------------------------------------------------------------

    We have determined that using lime (or any other caustic substance) 
to raise the pH of liquid discharged into the cooling pond could be a 
feasible control measure option for reducing fluoride emissions from 
cooling ponds; therefore, we are including this option in the NESHAP 
subpart AA final rule. The control measure option simultaneously raises 
the pH of the cooling pond water and lowers the concentration of 
soluble F, and, thus reducing the concentration of fluoride (including 
HF) that could be potentially evaporated into the atmosphere. Based on 
information provided in the 1978 EPA document, a greater than 90 
percent emission reduction in fluoride can be achieved by raising the 
pond water from pH 1.4 to pH 3.9. In the final rule, if this control 
measure is chosen, then the plan must include: the method used to raise 
the pH of the liquid discharged into the cooling pond, the target pH 
value (of the liquid discharged into the cooling pond) expected to be 
achieved by using the method, and the analyses used to determine and 
support the raise in pH. Moreover, this control measure is similar to 
an option that industry suggested in response to a meeting that 
occurred after the public comment period closed (see ``EPA Meeting 
Minutes for TFI Discussion March 12, 2015,'' and ``Summary of Potential 
Costs for Implementing Phosphate NESHAPs/Recommendations for 
Phosphogypsum Stack Work Practices, May 5, 2015,'' which are both 
available in Docket ID No. EPA-HQ-OAR-2012-0522). Industry suggested 
including an option that would require providing inputs to the gypsum 
dewatering stack system to react with and precipitate fluoride 
compounds to insoluble forms.
    With regard to the remaining potential control techniques 
identified in the 1978 EPA document (i.e., dry conveyance of gypsum and 
pretreatment of ore by calcining), we have determined that these 
control techniques are not likely to be used by industry because 
significant process changes would be required. Furthermore, with regard 
to pretreatment of ore by calcining, the 1978 EPA document states that 
off-gases from pretreating ore would still need to be scrubbed to 
remove F, and the scrubbing liquid from this process would likely be 
disposed of in a cooling pond (which would defeat the purpose of this 
technique). Therefore, we are not finalizing the NESHAP subpart AA 
final rule to include these two control measure options for controlling 
fugitive HF emissions from cooling ponds.
    Lastly, we agree with a commenter's request to add a control 
measure option (for cooling ponds) that would require developing a plan 
to optimize the size of cooling ponds to address fugitive HF emissions 
(as appropriate based on the conditions at the facility); therefore, we 
are including this option in the NESHAP subpart AA final rule. However, 
in order for a facility to be able to use this control measure option, 
its cooling pond evaluation must result in a reduction in overall 
cooling pond surface area. Fugitive HF emissions are calculated using 
an emission factor that is directly related to gypsum dewatering stack 
and pond surface area (tons HF per acre per year); therefore, 
minimizing

[[Page 50408]]

the surface area of the cooling pond(s) would minimize HF emissions. On 
a recent site visit (see ``Site Visits to Mosaic Plant City and Mosaic 
New Wales, March 4, 2015,'' which is available in Docket ID No. EPA-HQ-
OAR-2012-0522), we noticed that one company evaluated whether a 
reduction in the size of its cooling ponds could still support 
additional water due to rainfall and plant process water needs. 
However, the result of these evaluations did not lead to a change in 
size of its cooling ponds, and thus did not lead to a reduction in 
fugitive HF emissions from the cooling ponds. In the final rule, if 
this control measure is chosen, then the facility-specific evaluation 
plan must be certified by an independent licensed professional engineer 
or similarly qualified individual, and include the method used to 
reduce the total cooling pond footprint, the analyses used to determine 
and support the reduction in the total cooling pond surface area, and 
the amount of total cooling pond surface area that was reduced due to 
the facility-specific evaluation plan. Furthermore, we agree with the 
commenter who stated dredging cooling ponds is a good practice for 
maintaining cooling capacity. With regard to the commenter's request to 
include this activity (i.e., dredging cooling ponds) as a specific 
control measure option,\8\ we determined that this activity could be 
considered in the cooling pond evaluation; however, the evaluation 
would still need to lead to a change in size of the surface area of the 
cooling pond for it to qualify as a control measure in the final rule.
---------------------------------------------------------------------------

    \8\ Industry also suggested this control measure as an option to 
reducing fugitive HF emissions from cooling ponds in response to a 
meeting that occurred after the public comment period closed (see 
``EPA Meeting Minutes for TFI Discussion March 12, 2015,'' and 
``Summary of Potential Costs for Implementing Phosphate NESHAPs/
Recommendations for Phosphogypsum Stack Work Practices, May 5, 
2015,'' which are both available in Docket ID No. EPA-HQ-OAR-2012-
0522).
---------------------------------------------------------------------------

    We also evaluated an additional control measure option suggested by 
industry in response to a meeting that occurred after the public 
comment period closed (see ``EPA Meeting Minutes for TFI Discussion 
March 12, 2015,'' and ``Summary of Potential Costs for Implementing 
Phosphate NESHAPs/Recommendations for Phosphogypsum Stack Work 
Practices, May 5, 2015,'' which are both available in Docket ID No. 
EPA-HQ-OAR-2012-0522). Industry suggested including the option to 
``operate the cooling pond systems to adjust the active cooling surface 
area to address weather conditions, seasonal cooling needs and 
associated production changes. Cooling circuit adjustments may be 
accomplished through utilization of either fixed or floating flow 
diversion devices or by changing flows such that some of the heated 
water is diverted away from portions of the ponded area.'' However, we 
are not including this option in the final rule because it is not clear 
how the option reduces fugitive HF emissions from cooling ponds.
    v. Excluding Cooling Ponds from Management Plan--Comment. One 
commenter requests that the EPA revise the regulatory language in 
proposed 40 CFR 63.602 (d) through (f) that refers to each ``gypsum 
dewatering stack and cooling pond'' to instead refer only to each 
``gypsum dewatering stack.'' The commenter stated that the regulatory 
direction seems to encompass ponds that are not part of a ``gypsum 
dewatering stack.'' Another commenter claimed the rule implies that 
control measure options apply to cooling ponds distinctly from gypsum 
dewatering stacks. An additional commenter alleged that work practice 
standards should not apply to cooling ponds that are physically 
separate from gypsum stacks. This commenter pointed out that only one 
practice (submerging the discharge pipe) relates to cooling ponds, and 
because of the requirement to implement at least one practice for each 
``gypsum dewatering stack and cooling pond,'' then cooling ponds that 
fall within the proposed definition of a gypsum dewatering stack 
seemingly could choose to submerge the discharge pipe at the pond, or 
they could implement other techniques from the list.
    Response. The NESHAP subpart AA final rule clarifies that the 
gypsum dewatering stack and cooling pond management plan is intended to 
cover both gypsum dewatering stacks and cooling ponds. In response to a 
previous comment, we have included a new term ``gypsum dewatering stack 
system,'' revised the definition of ``gypsum dewatering stack'' to 
exclude cooling ponds, and have retained the proposed definition of 
``cooling pond'' in the final rule (see section V.C.3.b.i of this 
preamble for further details).
4. What is the rationale for our final approach pursuant to CAA 
sections 112(d)(2), 112(d)(3), and 112(h)?
    For the reasons provided above and in the preamble for the proposed 
rule, we are finalizing our proposal to eliminate the use of PM as a 
surrogate for Hg and are adding Hg and total fluoride emission limits 
for phosphate rock calciners to the NESHAP subpart AA final rule.
    For the reasons provided above, we are making the revisions, 
clarifications, and corrections noted in section V.C.2 in the NESHAP 
subpart AA final rule.

D. NSPS Review for the Phosphoric Acid Manufacturing Source Category

    The NSPS review focused on the emission limitations that have been 
adequately demonstrated to be achieved in practice, taking into account 
the cost of achieving such reduction and any non-air quality health and 
environmental impact and energy requirements. Determining the BSER that 
has been adequately demonstrated and the emission limitations achieved 
in practice necessarily involves consideration of emission reduction 
methods in use at existing phosphoric acid manufacturing plants. To 
determine the BSER, the EPA performed an extensive review of several 
recent sources of information, including a thorough search of the RACT/
BACT/LAER Clearinghouse (RBLC), section 114 data received from 
industry, and other relevant sources.
    Our review considered the emission limitations that are currently 
achieved in practice, and found that more stringent standards are not 
achievable for this source category. When evaluating the emissions from 
various process lines, we observed differences in emissions levels, but 
did not identify any patterns in emission reductions based on control 
technology configuration. More information concerning our NSPS review 
can be found in the memorandum, ``CAA Section 111(b)(1)(B) and 
112(d)(6) Reviews for the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production Source Categories.'' Though some of the sources 
are emitting at levels well below the current NSPS, other sources are 
not. We evaluated emissions based on control technologies and practices 
used by facilities, and found that the same technologies and practices 
yielded different results for different facilities. Therefore, we 
determined that we cannot conclude that new and modified sources would 
be able to achieve a more stringent NSPS. As explained in the proposed 
rule, all Phosphoric Acid Manufacturing NSPS (under subpart T and 
subpart U) emission sources, and the control technologies that would be 
employed, are the same as those for the NESHAP regulating phosphoric 
acid plants, such that we reached the same conclusion that there are no 
identified developments in technology or practices that results in 
cost-effective emission

[[Page 50409]]

reductions strategies. Therefore, we are finalizing our determination 
that revisions to NSPS subpart T and subpart U standards are not 
appropriate pursuant to CAA section 111(b)(1)(B).

E. Startup, Shutdown, and Malfunction Provisions for the Phosphoric 
Acid Manufacturing Source Category

1. What SSM provisions did we propose for the Phosphoric Acid 
Manufacturing source category?
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the U.S. Court of Appeals for the District of Columbia 
Circuit vacated portions of two provisions in the EPA's CAA section 112 
regulations governing the emissions of HAP during periods of SSM. 
Specifically, the Court vacated the SSM exemption contained in 40 CFR 
63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section 302(k) of 
the CAA, emissions standards or limitations must be continuous in 
nature and that the SSM exemption violates the CAA's requirement that 
some CAA section 112 standards apply continuously.
    We proposed to eliminate the SSM exemption in NESHAP subpart AA. 
Consistent with Sierra Club v. EPA, the EPA proposed standards in this 
rule that apply at all times. We also proposed to revise appendix A of 
subpart AA (the General Provisions Applicability Table) in several 
respects as is explained in more detail below. For example, we proposed 
to eliminate the incorporation of the General Provisions' requirement 
that the source develop an SSM plan. We also proposed to eliminate and 
revise certain recordkeeping and reporting related to the SSM exemption 
as described in detail in the proposed rule and summarized again here.
    In proposing the standards in this rule, the EPA took into account 
startup and shutdown periods and, for the reasons explained below, 
proposed work practice standards for periods of startup and shutdown in 
lieu of numeric emission limits. CAA section 112(h)(1) states that the 
Administrator may promulgate a design, equipment or operational work 
practice standard in those cases where, in the judgment of the 
Administrator, it is not feasible to prescribe or enforce an emission 
standard. CAA section 112(h)(2)(B) further defines the term ``not 
feasible'' in this context to apply when ``the application of 
measurement technology to a particular class of sources is not 
practicable due to technological and economic limitations.''
    Startup and shutdown periods at phosphoric acid manufacturing 
facilities generally only last between 30 minutes and 6 hours. Because 
of the variability and the relatively short duration, compared to the 
time needed to conduct a performance test, which typically requires a 
full working day, the EPA has determined that it is not feasible to 
prescribe a numeric emission standard for these periods. Furthermore, 
according to information provided by industry, it is possible that the 
feed rate (i.e., equivalent P2O5 feed, or rock 
feed) can be zero during startup and shutdown periods. During these 
periods, it is not feasible to consistently enforce the emission 
standards that are expressed in terms of lb of pollutant/ton of feed.
    Although we requested information on emissions and the operation of 
control devices during startup and shutdown periods in the CAA section 
114 survey issued to the Phosphoric Acid Manufacturing source category, 
we did not receive any emissions data collected during a startup and 
shutdown period (nor did we receive data during public comment of the 
proposed rule), and we do not expect that these data exist. However, 
based on the information for control device operation received in the 
survey, we concluded that the control devices could be operated 
normally during periods of startup or shutdown. Also, we believe that 
the emissions generated during startup and shutdown periods are lower 
than during steady-state conditions because the amount of feed 
materials introduced to the process during those periods is lower 
compared to normal operations. Therefore, if the emission control 
devices are operated during startup and shutdown, then HAP emissions 
will be the same or lower than during steady-state operating 
conditions.
    Consequently, we proposed a work practice standard rather than an 
emissions limit for periods of startup or shutdown. We proposed that 
control devices used on the various process lines in this source 
category are effective at achieving desired emission reductions 
immediately upon startup; therefore, during startup and shutdown 
periods, we proposed that sources begin operation of any control 
device(s) in the production unit prior to introducing any feed into the 
production unit. We also proposed that sources must continue operation 
of the control device(s) through the shutdown period until all feed 
material has been processed through the production unit.
    Periods of startup, normal operations and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead, they are, by 
definition, sudden, infrequent and not reasonably preventable failures 
of emissions control, process or monitoring equipment (40 CFR 63.2) 
(definition of malfunction). The EPA interprets CAA section 112 as not 
requiring emissions that occur during periods of malfunction to be 
factored into development of CAA section 112 standards. Under CAA 
section 112, emission standards for new sources must be no less 
stringent than the level ``achieved'' by the best controlled similar 
source and for existing sources generally must be no less stringent 
than the average emission limitation ``achieved'' by the best 
performing 12 percent of sources in the category. There is nothing in 
CAA section 112 that directs the EPA to consider malfunctions in 
determining the level ``achieved'' by the best performing sources when 
setting emission standards. As the U.S. Court of Appeals for the 
District of Columbia Circuit has recognized, the phrase ``average 
emissions limitation achieved by the best performing 12 percent of'' 
sources ``says nothing about how the performance of the best units is 
to be calculated.'' Nat'l Ass'n of Clean Water Agencies v. EPA, 734 
F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts for 
variability in setting emission standards, nothing in CAA section 112 
requires the Agency to consider malfunctions as part of that analysis. 
A malfunction should not be treated in the same manner as the type of 
variation in performance that occurs during routine operations of a 
source. A malfunction is a failure of the source to perform in a 
``normal or usual manner'' and no statutory language compels EPA to 
consider such events in setting CAA section 112 standards.
    Further, accounting for malfunctions in setting emission standards 
would be difficult, if not impossible, given the myriad different types 
of malfunctions that can occur across all sources in the category and 
given the difficulties associated with predicting or accounting for the 
frequency, degree and duration of various malfunctions that might 
occur. As such, the performance of units that are malfunctioning is not 
``reasonably'' foreseeable. See, e.g., Sierra Club v. EPA, 167 F.3d 
658, 662 (D.C. Cir. 1999) (``The EPA typically has wide latitude in 
determining the extent of data-gathering necessary to solve a problem. 
We generally defer to an agency's decision to proceed on the basis of 
imperfect scientific information, rather than to `invest the resources 
to conduct the perfect study.' ''). See also Weyerhaeuser v. Costle, 
590 F.2d 1011,

[[Page 50410]]

1058 (D.C. Cir. 1978) (``In the nature of things, no general limit, 
individual permit, or even any upset provision can anticipate all upset 
situations. After a certain point, the transgression of regulatory 
limits caused by `uncontrollable acts of third parties,' such as 
strikes, sabotage, operator intoxication or insanity, and a variety of 
other eventualities, must be a matter for the administrative exercise 
of case-by-case enforcement discretion, not for specification in 
advance by regulation.''). In addition, emissions during a malfunction 
event can be significantly higher than emissions at any other time of 
source operation. For example, if an air pollution control device with 
99 percent removal goes off-line as a result of a malfunction (as might 
happen if, for example, the bags in a baghouse catch fire) and the 
emission unit is a steady-state type unit that would take days to 
shutdown, the source would go from 99 percent control to zero control 
until the control device was repaired. The source's emissions during 
the malfunction would be 100 times higher than during normal 
operations, and the emissions over a 4-day malfunction period would 
exceed the annual emissions of the source during normal operations. As 
this example illustrates, accounting for malfunctions could lead to 
standards that are not reflective of (and significantly less stringent 
than) levels that are achieved by a well-performing non-malfunctioning 
source. It is reasonable to interpret CAA section 112 to avoid such a 
result. The EPA's approach to malfunctions is consistent with CAA 
section 112 and is a reasonable interpretation of the statute.
    In the event that a source fails to comply with the applicable CAA 
section 112(d) standards as a result of a malfunction event, the EPA 
would determine an appropriate response based on, among other things, 
the good faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions. 
The EPA would also consider whether the source's failure to comply with 
the CAA section 112(d) standard was, in fact, sudden, infrequent, not 
reasonably preventable and was not instead caused in part by poor 
maintenance or careless operation 40 CFR 63.2 (definition of 
malfunction).
    If the EPA determines in a particular case that an enforcement 
action against a source for violation of an emission standard is 
warranted, the source can raise any and all defenses in that 
enforcement action, and the federal district court will determine what, 
if any, relief is appropriate. The same is true for citizen enforcement 
actions. Similarly, the presiding officer in an administrative 
proceeding can consider any defense raised and determine whether 
administrative penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular, 
CAA section 112 is reasonable and encourages practices that will avoid 
malfunctions. Administrative and judicial procedures for addressing 
exceedances of the standards fully recognize that violations may occur 
despite good faith efforts to comply and can accommodate those 
situations.
    To address the U.S. Court of Appeals for the District of Columbia 
Circuit vacatur of portions of the EPA's CAA section 112 regulations 
governing the emissions of HAP during periods of SSM, Sierra Club v. 
EPA, 551 F.3d 1019 (D.C. Cir. 2008), we proposed to revise and add 
certain provisions to the Phosphoric Acid Manufacturing rule. As 
described in detail below, we proposed to revise the General Provisions 
table (appendix A) to change several references related to requirements 
that apply during periods of SSM. We also proposed to add other 
provisions to the Phosphoric Acid Manufacturing rule as described 
below.
    a. 40 CFR 63.608(b) General Duty. We proposed to revise the entry 
for 40 CFR 63.6(e)(1)(i) and (e)(1)(ii) in the General Provisions table 
(appendix A) by changing the ``yes'' in column three to ``no.'' Section 
63.6(e)(1)(i) describes the general duty to minimize emissions. Some of 
the language in that section is no longer necessary or appropriate in 
light of the elimination of the SSM exemption. We proposed instead to 
add general duty regulatory text at 40 CFR 63.608(b) that reflects the 
general duty to minimize emissions while eliminating the reference to 
periods covered by an SSM exemption. The current language in 40 CFR 
63.6(e)(1)(i) characterizes what the general duty entails during 
periods of SSM. With the elimination of the SSM exemption, there is no 
need to differentiate between normal operations, startup and shutdown 
and malfunction events in describing the general duty. Therefore, the 
language the EPA proposed does not include that language from 40 CFR 
63.6(e)(1). We also proposed to revise the entry for 40 CFR 
63.6(e)(1)(ii) in the General Provisions table (appendix A) by changing 
the ``yes'' in column three to ``no.'' Section 63.6(e)(1)(ii) imposes 
requirements that are not necessary with the elimination of the SSM 
exemption or are redundant of the general duty requirement being added 
at 40 CFR 63.608(b).
    b. SSM Plan. We proposed to revise the entry for 40 CFR 63.6(e)(3) 
in the General Provisions table (appendix A) by changing the ``yes'' in 
column three to ``no.'' Generally, these paragraphs require development 
of an SSM plan and specify SSM recordkeeping and reporting requirements 
related to the SSM plan. As noted, the EPA proposed to remove the SSM 
exemptions. Therefore, affected units will be subject to an emission 
standard during such events. The applicability of a standard during 
such events will ensure that sources have ample incentive to plan for 
and achieve compliance and thus the SSM plan requirements are no longer 
necessary.
    c. Compliance with Standards. We proposed to revise the entry for 
40 CFR 63.6(f) in the General Provisions table (appendix A) by changing 
the ``yes'' in column three to ``no.'' The current language of 40 CFR 
63.6(f)(1) exempts sources from non-opacity standards during periods of 
SSM. As discussed above, the Court in Sierra Club v. EPA vacated the 
exemptions contained in this provision and held that the CAA requires 
that some CAA section 112 standard apply continuously. Consistent with 
Sierra Club v. EPA, the EPA proposed to revise standards in this rule 
to apply at all times.
    d. 40 CFR 63.606 Performance Testing. We proposed to revise the 
entry for 40 CFR 63.7(e)(1) in the General Provisions table (appendix 
A) by changing the ``yes'' in column three to ``no.'' Section 
63.7(e)(1) describes performance testing requirements. The EPA instead 
proposed to add a performance testing requirement at 40 CFR 63.606(d). 
The performance testing requirements that were proposed differ from the 
General Provisions performance testing provisions in several respects. 
The proposed regulatory text does not allow testing during startup, 
shutdown, or malfunction. The proposed regulatory text does not include 
the language in 40 CFR 63.7(e)(1) that restated the SSM exemption and 
language that precluded startup and shutdown periods from being 
considered ``representative'' for purposes of performance testing. 
Furthermore, as in 40 CFR 63.7(e)(1), performance tests conducted under 
this subpart should not be conducted during malfunctions because 
conditions during malfunctions are often not representative of 
operating conditions.
    e. Monitoring. We proposed to revise the entry for 40 CFR 
63.8(c)(1)(i) and (iii) in the General Provisions table by changing the 
``yes'' in column three to

[[Page 50411]]

``no.'' The cross-references to the general duty and SSM plan 
requirements in those subparagraphs are not necessary in light of other 
requirements of 40 CFR 63.8 that require good air pollution control 
practices (40 CFR 63.8(c)(1)) and that set out the requirements of a 
quality control program for monitoring equipment (40 CFR 63.8(d)).
    We proposed to revise the entry for 40 CFR 63.8(d)(3) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to ``no.'' The final sentence in 40 CFR 63.8(d)(3) refers to the 
General Provisions' SSM plan requirement, which is no longer 
applicable. The EPA proposed to add to the rule at 40 CFR 63.608(c)(3) 
text that is identical to 40 CFR 63.8(d)(3), except that the final 
sentence is replaced with the following sentence: ``You must include 
the program of corrective action required under Sec.  63.8(d)(2) in the 
plan.''
    f. 40 CFR 63.607 Recordkeeping. We proposed to revise the entry for 
40 CFR 63.10(b)(2)(i) in the General Provisions table (appendix A) by 
changing the ``yes'' in column three to ``no.'' Section 63.10(b)(2)(i) 
describes the recordkeeping requirements during startup and shutdown. 
These recording provisions are no longer necessary because the EPA 
proposed that recordkeeping and reporting applicable to normal 
operations will apply to startup and shutdown. In the absence of 
special provisions applicable to startup and shutdown, such as a 
startup and shutdown plan, there is no reason to retain additional 
recordkeeping for startup and shutdown periods.
    We proposed to revise the entry for 40 CFR 63.10(b)(2)(ii) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to ``no.'' Section 63.10(b)(2)(ii) describes the recordkeeping 
requirements during a malfunction. The EPA proposed to add such 
requirements to 40 CFR 63.607(b). The regulatory text we proposed to 
add differs from the General Provisions it is replacing in that the 
General Provisions requires the creation and retention of a record of 
the occurrence and duration of each malfunction of process, air 
pollution control and monitoring equipment. The EPA proposed that this 
requirement apply to any failure to meet an applicable standard and 
that the source record the date, time and duration of the failure 
rather than the ``occurrence.'' The EPA also proposed to add to 40 CFR 
63.607(b) a requirement that sources keep records that include a list 
of the affected source or equipment and actions taken to minimize 
emissions, an estimate of the volume of each regulated pollutant 
emitted over the applicable standard and a description of the method 
used to estimate the emissions. Examples of such methods would include 
product-loss calculations, mass balance calculations, measurements when 
available or engineering judgment based on known process parameters. 
The EPA proposed requiring that sources keep records of this 
information to ensure that there is adequate information to allow the 
EPA to determine the severity of any failure to meet a standard, and to 
provide data that may document how the source met the general duty to 
minimize emissions when the source has failed to meet an applicable 
standard.
    We proposed to revise the entry for 40 CFR 63.10(b)(2)(iv) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to ``no.'' When applicable, the provision requires sources to 
record actions taken during SSM events when actions were inconsistent 
with their SSM plan. The requirement is no longer appropriate because 
SSM plans will no longer be required. The requirement previously 
applicable under 40 CFR 63.10(b)(2)(iv)(B) to record actions to 
minimize emissions and record corrective actions is now applicable by 
reference to 40 CFR 63.607.
    We proposed to revise the entry for 40 CFR 63.10(b)(2)(v) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to ``no.'' When applicable, the provision requires sources to 
record actions taken during SSM events to show that actions taken were 
consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
    We proposed to revise the entry for 40 CFR 63.10(c)(15) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to ``no.'' The EPA proposed that 40 CFR 63.10(c)(15) no longer 
apply. When applicable, the provision allows an owner or operator to 
use the affected source's SSM plan or records kept to satisfy the 
recordkeeping requirements of the SSM plan, specified in 40 CFR 
63.6(e), to also satisfy the requirements of 40 CFR 63.10(c)(10) 
through (12). The EPA proposed to eliminate this requirement because 
SSM plans would no longer be required, and, therefore, 40 CFR 
63.10(c)(15) no longer serves any useful purpose for affected units.
    g. 40 CFR 63.607 Reporting. We proposed to revise the entry for 40 
CFR 63.10(d)(5) in the General Provisions table (appendix A) by 
changing the ``yes'' in column three to ``no.'' Section 63.10(d)(5) 
describes the reporting requirements for startups, shutdowns and 
malfunctions. To replace the General Provisions reporting requirement, 
the EPA proposed to add reporting requirements to 40 CFR 63.607. The 
replacement language differs from the General Provisions requirement in 
that it eliminates periodic SSM reports as a stand-alone report. We 
proposed language that requires sources that fail to meet an applicable 
standard at any time to report the information concerning such events 
in the excess emission report already required under this rule. We 
proposed that the report must contain the number, date, time, duration 
and the cause of such events (including unknown cause, if applicable), 
a list of the affected source or equipment, an estimate of the volume 
of each regulated pollutant emitted over any emission limit, and a 
description of the method used to estimate the emissions (e.g., 
product-loss calculations, mass balance calculations, direct 
measurements or engineering judgment based on known process 
parameters). The EPA proposed this requirement to ensure that adequate 
information is available to determine compliance, to allow the EPA to 
determine the severity of the failure to meet an applicable standard, 
and to provide data that may document how the source met the general 
duty to minimize emissions during a failure to meet an applicable 
standard.
    The proposed rule eliminates the cross reference to 40 CFR 
63.10(d)(5)(i) that contains the description of the previously-required 
SSM report format and submittal schedule from this section. We proposed 
that these specifications would no longer be necessary because the 
events will be reported in otherwise required reports with similar 
format and submittal requirements. We proposed that owners or operators 
no longer be required to determine whether actions taken to correct a 
malfunction are consistent with an SSM plan because the plans would no 
longer be required.
    We proposed to revise the entry for 40 CFR 63.10(d)(5)(ii) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to ``no.'' Section 63.10(d)(5)(ii) describes an immediate report 
for SSM when a source failed to meet an applicable standard but did not 
follow the SSM plan. We proposed that we would no longer require owners 
and operators to report when actions taken during a startup, shutdown, 
or malfunction were not consistent with an SSM plan because the plans 
would no longer be required.

[[Page 50412]]

2. How did the SSM provisions change for the Phosphoric Acid 
Manufacturing source category?
    We are finalizing the proposed work practice standards for periods 
of startup and shutdown; however, in consideration of comments received 
during the public comment period for the proposed rulemaking (as 
discussed in sections V.E.3.a and V.E.3.b of this preamble), we are 
making changes to this work practice in order to clarify the standard 
applies in lieu of numeric emission limits and to clarify how 
compliance with the standard is demonstrated. Additionally, as 
discussed in section V.E.3.c of this preamble, we added a definition of 
``startup'' and ``shutdown'' in the final rule to specify when startup 
begins and ends, and when shutdown begins and ends.
3. What key comments did we receive on the SSM provisions, and what are 
our responses?
    We received comments regarding the proposed revisions to remove the 
SSM exemptions for the Phosphoric Acid Manufacturing source category, 
and the proposed work practice standards for periods of startup and 
shutdown. The following is a summary of some of the comments specific 
to the proposed work practice standards and our response to those 
comments. Other comments and our specific responses to those comments 
can be found in the Comment Summary and Response document available in 
the docket for this action (EPA-HQ-OAR-2012-0522).
    a. Work Practice Standard In Place Of Emission Limits--Comment. One 
commenter argued that the EPA should specify that the proposed work 
practices for plant startup and shutdown periods apply ``in lieu of'' 
any other emission standards, and that such periods should not be 
counted for testing, monitoring, or operating parameter requirements. 
The commenter noted that the proposed rule at 40 CFR 63.602(h) requires 
the use of work practices ``to demonstrate compliance with any emission 
limits'' during periods of startup and shutdown. The commenter agrees 
with the EPA's conclusion that it is not feasible to apply numeric 
limits to startup and shutdown because certain variables required to 
calculate emissions would be zero during such periods. The commenter 
also agreed with the EPA that existing emission control devices would 
still be effective during periods of startup or shutdown, if activated. 
However, the commenter recommended that the rule should clarify that 
startup and shutdown events should not be required to comply with the 
monitoring and operating parameter requirements because startup and 
shutdown events generally are not representative of operating 
conditions for other compliance purposes, such as emissions testing. 
Instead, the commenter, as well as a second commenter, recommended 
that, because the startup and shutdown periods are not representative, 
the rule should only require that (1) all emission control devices be 
kept active, and (2) owners and operators follow the general duty to 
control emissions, and owners and operators should not be required to 
monitor operating parameters during startup and shutdown periods.
    The commenter argued that the approach in the proposed rule at 40 
CFR 63.602(h) to require the use of work practices ``to demonstrate 
compliance with any emission limits'' during periods of startup and 
shutdown is ``directly inconsistent'' with the approach that the EPA 
has applied to other source categories, where such practices clearly 
were prescribed ``in lieu of'' numeric emission limits that would 
otherwise apply. (The commenter cites, for example, 78 FR 10015, 
February 12, 2013.) According to the commenter, the EPA made it clear 
in other industries' rules that such work practice standards apply ``in 
place of'' or ``in lieu of'' numeric standards, including with respect 
to monitoring and recordkeeping requirements. (See id. at 10013 and 
10015.) The commenter argues that according to the preamble language 
cited for those other industries, ``there will no longer be a numeric 
emission standard applicable during startup and shutdown,'' and the EPA 
recognizes that ``the recordkeeping requirement must change to reflect 
the content of the work practice standard''(Id. at 10014).
    Therefore, the commenter recommended that the EPA should clearly 
explain that work practices are not applied to ``demonstrate 
compliance'' with numeric limits under subpart AA, which the EPA 
acknowledges are ``not feasible'' for startup and shutdown periods, 
and, instead, the work practices should be written to apply ``in lieu 
of'' the numeric limits during those periods. The commenter argues that 
without this clarification, it will appear that both the numeric 
standards and the work practice standards would apply during startup 
and shutdown. The commenter suggests that this can be corrected in the 
rule by using the ``in lieu of'' language used for other industries.
    Response. The commenter is correct that our intention at proposal 
was that the numeric emission limits would not apply during periods of 
startup and shutdown, but that facilities would comply with the work 
practice instead. We did not intend for the work practice to be a 
method to demonstrate compliance with the emission limit. We are 
replacing the phrasing ``to demonstrate compliance'' with ``in lieu 
of'' as this language is more consistent with our original intent. 
Accordingly, in the final rule, 40 CFR 63.602(f) specifies that the 
emission limits of 40 CFR 63.602(a) do not apply during periods of 
startup and shutdown. Instead, owners and operators must follow the 
work practice specified in 40 CFR 63.602(f). See section V.E.3.b of 
this preamble for our response to commenters' argument that owners and 
operators should not be required to monitor operating parameters during 
startup and shutdown periods.
    b. Applicability Of Operating Limits--Comment. Two commenters 
recommended that the EPA amend the rule to make clear that the work 
practice standards for startup and shutdown also apply in lieu of the 
parametric monitoring requirements set forth in subpart AA and make 
explicit that parametric operating requirements do not apply during 
times of startup and shutdown.
    One commenter argued that when the EPA established the flow rate 
and pressure drop parametric monitoring requirements in its 1999 final 
rule, the EPA concluded that requiring continuous monitoring of these 
parameters ``help[ed] assure continuous compliance with the emission 
limit'' (64 FR 31365, June 10, 1999). The commenter also asserted that 
the rules specify that ``[t]he emission limitations and operating 
parameter requirements of this subpart do not apply during periods of 
startup, shutdown, or malfunction . . .'' (40 CFR 63.600(e)). The 
commenter argued that this was a reasonable action because the 
operating parameter ranges are established during annual performance 
tests, and these tests cannot be performed during startup and shutdown 
conditions.
    The commenter suggested that in the proposed rule, the EPA exempted 
compliance with the emission limits during startup and shutdown 
periods, imposed work practice standards in lieu thereof, and retained 
the prohibition on conducting a performance test during periods of 
startup or shutdown (79 FR 66570 (proposed 40 CFR 63.606(d)). The 
commenter suggested that the proposed rule is silent on the 
applicability of the parametric monitoring requirements during startup 
and shutdown. The commenter asserted that because the parametric 
monitoring provisions

[[Page 50413]]

provide an inference of compliance with the emission limits (64 FR 
31365, June 10, 1999), and these emission limits do not apply during 
startup and shutdown, the commenter concluded that the parametric 
monitoring provisions similarly should not apply during startups and 
shutdowns.
    The commenters pointed to two recent EPA NESHAP rulemakings to 
support their conclusion. First, the commenters argued that in its 
industrial, commercial and institutional boilers and process heaters 
NESHAP reconsideration proposal (hereinafter, the ``Boiler NESHAP''), 
the EPA, responding to a comment soliciting clarification ``that the 
operating limits and opacity limits do not apply during periods of 
startup and shutdown,'' stated that with the finalization of work 
practice standards, ``EPA agrees that the requested clarification is 
what was intended in the final rule'' (76 FR 80598 and 80615, December 
23, 2011). The commenters asserted that to this end, in its response to 
the reconsideration, the EPA made clear that affected sources must 
comply with ``all applicable emissions and operating limits at all 
times the unit is operating except for periods that meet the 
definitions of startup and shutdown in this subpart, during which times 
you must comply with these work practices'' (78 FR 7138 and 7142, 
January 31, 2013). The commenters noted that in the Boiler NESHAP 
regulations, the EPA required the implementation of work practice 
standards in lieu of compliance with the operating parameter 
requirements during startup and shutdown by (1) Excluding periods of 
startup and shutdown from the averaging period (Id. at 7187, 40 CFR 
63.7575, the definition of a 30-day rolling average'' excludes ``hours 
during startup and shutdown''), and (2) expressly stating that the 
``standards'' (the emission limits and operating requirements) do not 
apply during periods of startup or shutdown. (Id. at 7163, 40 CFR 
63.7500(f), titled ``What emission limitations, work practice 
standards, and operating limits must I meet?'' applies ``at all times 
the affected unit is operating, except during periods of startup and 
shutdown during which time you must comply only with Table 3 of this 
subpart.'')
    Second, the commenters argued that in its Portland Cement NESHAP, 
the EPA specified an operating limit for kilns, identified as a 
temperature limit established during a performance test, and that the 
temperature limit applied at all times the raw mill is operating, 
``except during periods of startup and shutdown'' (78 FR 10039, 
February 12, 2013, 40 CFR 63.1346(a)(1)). Further, for the continuous 
monitoring requirements, including operating limits, the Portland 
Cement NESHAP required operating of the monitoring system at all times 
the affected source is operating, ``[e]xcept for periods of startup and 
shutdown'' (Id. at 10041, 40 CFR 63.1348(b)(1)(ii)).
    The commenters argued that given the EPA's conclusion in the 
proposed rule that the emission limits should not apply during startup 
and shutdown, and because the parametric monitoring requirements are 
established during a performance test (which cannot be performed during 
a startup or a shutdown) and used to infer compliance with the emission 
limits, the EPA should make clear in the final rule that the operating 
parameters requirements do not apply during startup or shutdown. The 
commenter recommended that the EPA should make this explicit: (1) In 
the operating and monitoring requirement section of subpart AA 
(proposed 40 CFR 63.605), and (2) by defining the averaging period 
(currently daily) as excluding periods of startup and shutdown 
(proposed 40 CFR part 63, subpart AA, Table 4.) As an alternative, the 
commenters recommended that if the EPA continues to require compliance 
with the parametric monitoring requirements during startup and shutdown 
periods, then the EPA should adopt a longer averaging period, from 
daily to 30 days, to allow for the effects of startups and shutdowns to 
be reduced by a longer period of steady-state operations. The commenter 
noted that the Boiler NESHAP has a 30-day averaging period for pressure 
drop and liquid flow rate, and excludes periods of startup and shutdown 
from the averaging period (40 CFR 63.7575, definition of ``30-day 
rolling average'' and 40 CFR part 63, subpart DDDDD, Table 4.) The 
commenter stated that a 30-day averaging period would be substantially 
more stringent than the Boiler NESHAP approach since it would include 
periods of startup and shutdown, while at the same time avoid 
misleading ``exceedances'' caused by the inclusion of periods of 
startup and shutdown compared to daily average parametric limits.
    Response. We disagree with the commenters about the applicability 
of the operating limits. Based on these comments, we have clarified in 
the final rule at 40 CFR 63.602(f) that to comply with the work 
practice during periods of startup and shutdown, facilities must 
monitor the operating parameters specified in Table 3 to subpart AA and 
comply with the operating limits specified in Table 4 of subpart AA. 
The purpose of the work practice is to ensure that the air pollution 
control equipment that is used to comply with the emission limit during 
normal operations is operated during periods of startup and shutdown. 
Monitoring of control device operating parameters is necessary to 
demonstrate compliance with the work practice. We have concluded that 
it is reasonable for the control device at phosphoric acid processes to 
meet the same operating limits during startup and shutdown that apply 
during normal operation, and that it is not necessary to specify 
different averaging times for periods of startup and shutdown. Meeting 
the operating limits of Table 4 of subpart AA will ensure that owners 
and operators meet the General Duty requirement to operate and maintain 
the affected source and associated air pollution control equipment in a 
manner consistent with safety and good air pollution control practices 
for minimizing emissions.
    The analogies that the commenters made to the Industrial Boiler 
NESHAP and the Portland Cement NESHAP are not relevant to this 
rulemaking. In each rulemaking, we consider the feasibility of applying 
standards during startup and shutdown based on relevant process 
considerations for each source category, the pollutants regulated, and 
control devices on which the rule is based. In developing this rule, we 
obtained information on the operation of control devices during startup 
and shutdown periods in the CAA section 114 survey issued to the 
phosphoric acid manufacturing industry. Based on survey results, we 
concluded that for this source category, control devices (i.e., 
absorbers and WESP) could be operated during periods of startup and 
shutdown. We found no indication that process operations during startup 
and shutdown would interfere with the ability to operate the relevant 
control devices according to good engineering practice. Moreover, the 
commenters provided no technical justification as to why a different 
operating limit is needed during startup and shutdown.
    Regarding the comparison to the Industrial Boiler NESHAP, the 
operation of boilers and their associated control devices are different 
than phosphoric acid plants. While boiler control devices do not have 
to comply with specific operating limits during startup or shutdown, 
they must meet a work practice that includes firing clean fuels, 
operating relevant control devices (e.g., absorbers) as expeditiously 
as possible, and monitoring the applicable operating parameters (e.g., 
flow rate) to demonstrate that the control devices are being operated 
properly. The EPA

[[Page 50414]]

currently is reconsidering the control requirements for industrial 
boilers during startup and shutdown (80 FR 3090, January 21, 2015). In 
the proposed action on reconsideration, we pointed out that some of the 
control devices used for boilers cannot be operated during the full 
duration of startup and shutdown because of safety concerns and the 
possibility of control equipment degradation due to fouling and 
corrosion. The control devices used for phosphoric acid production do 
not pose these same risks. Likewise, the fact the Portland Cement 
NESHAP does not require monitoring of kiln temperature during startup 
and shutdown is not relevant. The Portland Cement NESHAP requires 
maintaining a kiln temperature as part of the MACT operating limit. The 
operating limit for the Portland Cement NESHAP does not apply during 
startup and shutdown because it is not physically possible to maintain 
a constant temperature during startup and shutdown of a kiln. In 
contrast, the feasibility of operating the control devices used to 
control HAP emissions from phosphoric acid manufacturing is not limited 
by specific process operating conditions. Therefore, it is feasible to 
operate the devices during startup and shutdown, and we have determined 
that it is reasonable to do so considering cost, nonair health and 
environmental impacts, and energy requirements.
    c. Definition Of Startup And Shutdown--Comment. Several commenters 
argued that the EPA's proposed work practice standard for periods of 
startup and shutdown failed to account for how equipment in the 
phosphoric acid industry works. In order to comply with the proposed 
startup and shutdown requirements, the operator must begin operation of 
any control device(s) being used at the affected source prior to 
introducing any feed into the affected source and continue operation of 
the control device(s) through the shutdown period until all feed 
material has been processed through the affected source. The commenters 
noted that it is not feasible to process all feed material from a 
process prior to shutting down most equipment at a facility. For 
example, the phosphoric acid reactors and beds in the calciners may not 
be able to process all the feed material in them prior to shutdown and 
there would always still be feed material left in the equipment even 
after it is shutdown. The same would be true for nearly all process 
units in the industry. The commenters requested that the EPA revise 40 
CFR 63.602(h) to require compliance with the work practice standard 
only up to the point in time when no more feed or in-process materials 
are being introduced into the production unit.
    Two commenters agreed with other commenters that it is not feasible 
to base the conclusion of a ``shutdown'' on the point at which all feed 
has ``been processed.'' Instead, they suggested that the EPA should 
clarify the work practice standard of keeping all emission control 
equipment active during shutdowns. The commenters reported that 
facilities in the industry consider the commencement of ``shutdown'' as 
the moment at which the plant ceases adding feed to the affected 
process, rather than basing shutdown on when all feed materials have 
been processed through the process. The commenters recommended that the 
EPA should define ``shutdown'' to begin when the facility ceases adding 
feed to an affected process line, and to conclude when the affected 
process line equipment is deactivated, even though some feed or 
residues may still be present within particular parts of the process.
    One of the commenters also noted that it is common practice to have 
short-term shutdown of process inputs for temporary maintenance work 
(including work on emission control equipment) where the entire system 
is not emptied. In these cases, feed of phosphoric acid and ammonia to 
the process is suspended as is flow from the reactor to the granulator. 
The commenter argued that because the source of fluoride to the system 
has ceased and dust generating material flows are suspended, there 
should be no significant source of emissions to control, and it is not 
necessary to require the use of control devices until all feed material 
has been processed. Instead, the commenter recommended that an affected 
entity should be allowed to turn off control devices when reactor and 
granulator feeds have been stopped, unless the system is being emptied, 
in which case control devices should be required as long as the 
material handling system is in operation.
    Response. We agree with the commenters that the rule needs to have 
a more precise definition of startup and shutdown that more clearly and 
reasonably establishes the times when the work practice applies and 
when the emission limits apply. Accordingly, we added a definition of 
``startup'' and ``shutdown'' in the definitions section of the final 
rule to specify when startup begins and ends, and when shutdown begins 
and ends.
    Based on additional information provided by industry (see ``Email 
Correspondence Received After Comment Period re Startup Shutdown (May 
5, 2015),'' which is available in Docket ID No. EPA-HQ-OAR-2012-0522), 
we are including a definition of startup in the final rule. The final 
rule defines startup as commencing when any feed material is first 
introduced into an affected source and ends when feed material is fully 
loaded into the affected source. Regarding shutdown, we agree with the 
commenters that it is not feasible to process all feed material from a 
process prior to shutting down most equipment at a facility. Such 
requirement would imply that the control device must be operated after 
the shutdown ends. The final rule defines shutdown as commencing when 
the facility ceases adding feed to an affected source and ends when the 
affected source is deactivated, regardless of whether feed material is 
present in the affected source. This definition will address concerns 
about temporary shutdowns as well as shutdowns of longer duration.
    In addition, the final rule at 40 CFR 63.602(f) specifies that any 
control device used at the affected source must be operated during the 
entire period of startup and shutdown, and must meet the operating 
limits in Table 4 of the final rule.
4. What is the rationale for our final decisions for the SSM 
provisions?
    For the reasons provided above and in the preamble for the proposed 
rule, we are finalizing the proposed revisions to the General 
Provisions table (appendix A of NESHAP subpart AA) to change several 
references related to requirements that apply during periods of SSM. 
For these same reasons, we are also finalizing the addition of the 
following proposed provisions to NESHAP subpart AA: (1) Work practice 
standards for periods of startup and shutdown in lieu of numeric 
emission limits; (2) the general duty to minimize emissions at all 
times; (3) performance testing conditions requirements; (4) site-
specific monitoring plan requirements; and (5) malfunction 
recordkeeping and reporting requirements.

F. Other Changes Made to the Phosphoric Acid Manufacturing NESHAP and 
NSPS

1. What other changes did we propose for the Phosphoric Acid 
Manufacturing NESHAP and NSPS?
    a. Clarifications to Applicability and Certain Definitions--i. 
NESHAP Subpart AA. As stated in the preamble to the proposed rule, to 
ensure the emission standards reflect inclusion of HAP emissions from 
all sources in the source category, we proposed to amend the

[[Page 50415]]

definitions of WPPA process line, SPA process line, and PPA process 
line to include relevant emission points, including clarifiers and 
defluorination systems at WPPA process lines, and oxidation reactors at 
SPA production lines. We also proposed removing text from the 
applicability section that is duplicative of the revised definitions.
    We also proposed revising the term ``gypsum stack'' to ``gypsum 
dewatering stack'' in order to help clarify the meaning of this 
fugitive emission source, and to alleviate any potential misconception 
that the ``stack'' is a point source. Other changes we proposed 
included the addition of definitions for ``cooling pond,'' ``phosphoric 
acid defluorination process,'' ``process line,'' and ``raffinate 
stream.''
    ii. NSPS Subpart T. As stated in the preamble to the proposed rule, 
to ensure the emission standards we proposed reflected inclusion of 
total fluoride emissions from all sources in the defined source 
category, we proposed to amend the definition of WPPA plant to include 
relevant emission points, including clarifiers and defluorination 
systems. We also proposed to remove text from the applicability section 
that is duplicative of the revised definitions.
    iii. NSPS Subpart U. To ensure the emission standards we proposed 
reflected inclusion of total fluoride emissions from all sources in the 
defined source category, we proposed to amend the definition of SPA 
plant to include relevant emission points, including oxidation 
reactors. We also proposed to remove text from the applicability 
section that is duplicative of the revised definitions.
    b. Testing, Monitoring, Recordkeeping and Reporting --i. NESHAP 
Subpart AA. As stated in the preamble to the proposed rule, to provide 
flexibility, we proposed several monitoring options, including pressure 
and temperature measurements, as alternatives to monitoring of absorber 
differential pressure. We also proposed monitoring the absorber inlet 
gas flow rate along with the influent absorber liquid flow rate (and 
determining liquid-to-gas ratio) in lieu of monitoring only the 
absorber inlet liquid flow rate.
    In addition, we proposed removing the requirement that facilities 
may not implement new operating parameter ranges until the 
Administrator has approved them, or 30 days have passed since 
submission of the performance test results. We proposed that facilities 
must immediately comply with new operating ranges when they are 
developed and submitted; and new operating ranges must be established 
using the most recent performance test conducted by a facility, which 
allows for changes in control device operation to be appropriately 
reflected.
    As stated in the preamble to the proposed rule, we modified the 
language for the conditions under which testing must be conducted to 
require that testing be conducted at ``maximum representative operating 
conditions'' for the process.\9\
---------------------------------------------------------------------------

    \9\ Based on the EPA memorandum, ``Issuance of the Clean Air Act 
National Stack Testing Guidance,'' dated April 27, 2009.
---------------------------------------------------------------------------

    In keeping with the general provisions for CMS (including CEMS and 
continuous parameter monitoring system (CPMS)), we proposed the 
addition of a site-specific monitoring plan and calibration 
requirements for CMS. Provisions were also proposed that included 
electronic reporting of stack test data. We also proposed modifying the 
format of NESHAP subpart AA to reference tables for emissions limits 
and monitoring requirements.
    Finally, we proposed HF standards in NESHAP subpart AA by 
translating the current total fluoride limits (lb total F/ton 
P2O5 feed) into HF limits (lb HF/ton 
P2O5 feed). To comply with HF standards, we 
proposed that facilities use EPA Method 320.
    ii. NSPS Subpart T. We proposed new monitoring and recordkeeping 
requirements for any WPPA plant that commences construction, 
modification, or reconstruction after November 7, 2014 to ensure 
continuous compliance with the standard. As stated in the preamble to 
the proposed rule, to ensure that the process scrubbing system is 
properly maintained over time; ensure continuous compliance with 
standards; and improve data accessibility, we proposed the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. We also proposed that the owner or operator 
keep records of the daily average pressure drop through the process 
scrubbing system, and keep records of deviations.
    For consistency with terminology used in the associated NESHAP 
subpart AA, we proposed changing the term ``process scrubbing system'' 
to ``absorber'' in NSPS subpart T.
    iii. NSPS Subpart U. We proposed new monitoring and recordkeeping 
requirements for any SPA plant that commences construction, 
modification or reconstruction after November 7, 2014 to ensure 
continuous compliance with the standard. As stated in the preamble to 
the proposed rule, to ensure that the process scrubbing system is 
properly maintained over time; ensure continuous compliance with 
standards; and improve data accessibility, we proposed the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. We also proposed that the owner or operator 
keep records of the daily average pressure drop through the process 
scrubbing system, and keep records of deviations.
    For consistency with terminology used in the associated NESHAP 
subpart AA, we proposed changing the term ``process scrubbing system'' 
to ``absorber'' in NSPS subpart U.
2. How did the provisions regarding these other proposed changes to the 
Phosphoric Acid Manufacturing NESHAP and NSPS change since proposal?
    a. Clarifications to Applicability and Certain Definitions--i. 
NESHAP Subpart AA. In consideration of comments received during the 
public comment period for the proposed rulemaking, we are adopting the 
proposed clarifications for oxidation reactors as discussed in section 
V.F.3.a.i of this preamble; however, we are also revising the 
definition of oxidation reactor in the final rule to clarify that 
oxidizing agents may include: Nitric acid, ammonium nitrate, or 
potassium permanganate. Also, in consideration of comments received 
(see section V.F.3.a.ii of this preamble for details), we are not 
adopting the proposed clarifications for defluorination systems and 
clarifiers.
    We have not made any change to the proposed revision to rename 
``gypsum stack'' to ``gypsum dewatering stack.'' We have also not made 
any changes to the proposed definitions for ``cooling pond'' and 
``raffinate stream''; however, we are removing the proposed definitions 
for ``phosphoric acid defluorination process'' and ``process line'' for 
reasons discussed in sections V.F.3.a.ii and V.F.3.a.iii of this 
preamble, respectively.
    Finally, we are removing the proposed language ``includes, but is 
not limited to'' in the definitions of WPPA, SPA, and PPA process lines 
for reasons discussed in section V.F.3.a.iv of this preamble.
    ii. NSPS Subpart T. In consideration of comments received (see 
section V.F.3.a.ii of this preamble for details), we are not adopting 
the proposed clarifications for defluorination systems and clarifiers. 
We are also removing the proposed language ``includes, but is not 
limited to'' in the definitions of WPPA plant for reasons discussed in 
section V.F.3.a.iv of this preamble.

[[Page 50416]]

    iii. NSPS Subpart U. In consideration of comments received during 
the public comment period for the proposed rulemaking, we are adopting 
the proposed clarifications for oxidation reactors as discussed in 
section V.F.3.a.i of this preamble; however, we are also revising the 
proposed definition of oxidation reactor in the final rule to clarify 
that oxidizing agents may include: Nitric acid, ammonium nitrate, or 
potassium permanganate. We are also removing the proposed language 
``includes, but is not limited to'' in the definitions of SPA plant for 
reasons discussed in section V.F.3.a.iv of this preamble.
    b. Testing, Monitoring, Recordkeeping and Reporting--i. NESHAP 
Subpart AA. We have not made any changes in our proposed determination 
that pressure drop is not an appropriate monitoring parameter for 
absorbers that are designed to operate with pressure drops of 5 inches 
of water column or less. However, in consideration of comments received 
during the public comment period for the proposed rulemaking, we are 
not adopting the proposed options to monitor: (1) The temperature at 
the wet scrubber gas stream outlet and pressure at the liquid inlet of 
the absorber, or (2) the temperature at the scrubber gas stream outlet 
and scrubber gas stream inlet. Instead, we have revised Table 3 of 
NESHAP subpart AA to require liquid-to-gas ratio monitoring for low-
energy absorbers, and influent liquid flow and pressure drop monitoring 
for high-energy absorbers; and we are keeping liquid-to-gas ratio 
monitoring as an option for high-energy absorbers in the final rule. 
(See section V.F.3.b.i and V.F.3.b.ii of this preamble for details.)
    In addition to these revisions, we are making corrections at 40 CFR 
63.607(a) to clarify the procedures for establishing a new operating 
limit based on the most recent performance test. We are also revising 
the requirements at 40 CFR 63.605(d)(1)(ii)(B) of the final rule to 
remove the requirement that facilities must request and obtain approval 
of the Administrator for changing operating limits. (See section 
V.F.3.b.iii and V.F.3.b.iv of this preamble for details.)
    Also, for reasons discussed in the in the Comment Summary and 
Response document available in the docket, we are revising the annual 
testing schedule in the final rule at 40 CFR 63.606(b), and the 
terminology for ``maximum representative operating conditions'' in the 
final rule at 40 CFR 63.606(d).
    We are not making any changes to the proposed addition of a site-
specific monitoring plan and calibration requirements for CMS. We are 
also keeping the proposed term ``absorber'' in lieu of ``scrubber,'' as 
well as the proposed format of NESHAP subpart AA to reference tables 
for emissions limits and monitoring requirements.
    Lastly, we are retaining the current total fluoride limits and not 
adopting the proposed HF standards and associated EPA Method 320 
testing in NESHAP subpart AA (see section V.F.3.c of this preamble for 
details).
    ii. NSPS Subpart T. We are not making changes to the proposed 
monitoring and recordkeeping requirements for any WPPA plant that 
commences construction, modification or reconstruction after August 19, 
2015 to ensure continuous compliance with the standard. We are also 
keeping the proposed term ``absorber'' in lieu of ``process scrubbing 
system.''
    iii. NSPS Subpart U. We are not making changes to the proposed 
monitoring and recordkeeping requirements for any SPA plant that 
commences construction, modification, or reconstruction after August 
19, 2015 to ensure continuous compliance with the standard. We are also 
keeping the proposed term ``absorber'' in lieu of ``process scrubbing 
system.''
3. What key comments did we receive on the other changes to the 
Phosphoric Acid Manufacturing NESHAP and NSPS, and what are our 
responses?
    Several comments were received regarding the proposed 
clarifications to applicability and certain definitions, revisions to 
testing, monitoring, recordkeeping and reporting, translation of total 
fluoride to HF emission limits, and revisions to other provisions for 
the Phosphoric Acid Manufacturing source category. The following is a 
summary of significant comments and our response to those comments. 
Other comments received and our responses to those comments can be 
found in the Comment Summary and Response document available in the 
docket for this action (EPA-HQ-OAR-2012-0522).
    a. Applicability Clarifications and Certain Definitions--i. 
Oxidation Reactors--Comment. Several commenters remarked that the 
proposed definition of SPA process line to include oxidation reactors 
is problematic and goes beyond clarification. These commenters 
requested that the EPA develop more specific language or provide a 
clear technical basis under the CAA because any equipment that was not 
expressly included in EPA's MACT floor calculations should not be 
included in the affected source definition.
    Commenters mentioned that the EPA's memorandum ``Applicability 
Clarifications to the Phosphoric Acid Manufacturing Source Category,'' 
which is available in the docket for this action, captured four 
facilities, but it was not clear whether the PCS Aurora facility was 
included in the count. These commenters stated that the oxidation step 
at this facility is carried out in agitated tanks that do not have any 
emissions control, and the emissions from the oxidation step are not 
included in their annual performance testing (when demonstrating 
compliance with the current total fluoride limits). The commenters said 
that it was not clear whether this oxidation step involves an 
``oxidation reactor'' as proposed; and, if it does, the commenters 
argued that the EPA has not considered additional costs imposed by 
including ``any equipment that uses an oxidizing agent to treat 
phosphoric acid'' within the scope of the NESHAP at 40 CFR part 63, 
subpart AA.
    Response. We are adopting the proposed SPA process line definition 
in NESHAP subpart AA, and the proposed SPA plant definition in NSPS 
subpart U, to include oxidation reactors. Based on information in 
process flow diagrams provided by facilities, we initially believed 
that oxidation reactors were part of the SPA process lines that would 
have been considered in the original MACT analysis, and, thus subject 
to the existing limits. In response to comments that stated the 
opposite was true, we searched historical data, specifically the 1996 
memorandum ``National Emission Standards for Hazardous Air Pollutants 
from Phosphoric Acid Manufacturing and Phosphate Fertilizers 
Production; Proposed Rules--Draft Technical Support Document and 
Additional Technical Information'' (1996 TSD). The 1996 TSD lists, in 
Attachment 2, the test data for SPA process lines that were assembled 
for the MACT floor analysis (the 1996 TSD is item II-B-20 in Docket A-
94-02). Based on this review as well as a facility construction air 
permit, we determined that oxidation reactor emissions from at least 
one facility, PCS White Springs (see the emission point ``Occidental, 
Suwanee Rv., FL-G'' in the 1996 TSD), were included with this assembled 
SPA test dataset. It is possible that three other facilities (see the 
emission points ``J.R. Simplot, Pocatello, ID'' for the Simplot Don-
Pocatello facility, ``Nu-West, Soda Springs, ID'' for the Agrium Nu-
West facility, and ``Texasgulf, Aurora, NC'' for the PCS Aurora 
facility in the 1996 TSD) with oxidation reactors were also included in 
this original dataset since we know today that these facilities have 
oxidation reactors; however, it is unclear whether the oxidation 
reactors

[[Page 50417]]

at these facilities were operating when the dataset was assembled. 
Nevertheless, based on the emission point ``Occidental, Suwanee Rv., 
FL-G,'' SPA process lines that incorporate an oxidation reactor were 
included as part of the SPA emissions dataset that was evaluated in 
order to conduct the MACT floor analysis.
    In addition, the EPA's technology review revealed that SPA process 
lines at four different facilities include an oxidation reactor to 
remove organic impurities from the acid. We determined that one of 
these facilities (Simplot Don-Pocatello) already ducts their oxidation 
reactor emissions through their SPA process line wet scrubber, and is 
achieving compliance with the SPA total fluoride emission limit. For 
two of these facilities (PCS White Springs and Agrium Nu-West), we 
determined that when their oxidation reactor emissions are combined 
with the rest of their SPA process line emissions, the facilities are 
in compliance with the total fluoride emission limit. Therefore, for 
these three facilities it would not be necessary to upgrade existing 
control systems, or to install a control system, in order to comply 
with the rule.
    With regard to the oxidation reactor at the fourth facility (PCS 
Aurora), the Agency has determined that this process (i.e., an 
oxidation step carried out in agitated tanks) does qualify as an 
oxidation reactor. Based on information that we received from industry 
after the public comment period ended for the proposal (see docket item 
EPA-HQ-OAR-2012-0522-0051), potassium permanganate is used in the PCS 
Aurora oxidation step. This oxidizing agent was one of three 
specifically cited in our memorandum ``Applicability Clarifications to 
the Phosphoric Acid Manufacturing Source Category,'' which is available 
in the docket for this action, so based on the data available, this 
oxidation step should be included as part of the SPA process line 
emissions when determining compliance with the SPA total fluoride 
emission limit. Furthermore, based on this same information that we 
received from industry after the public comment period ended for the 
proposal, PCS Aurora may need to install a new absorber in order to 
control its oxidation process emissions due to logistical complications 
and concerns about inadequate capacity of other existing absorbers at 
their SPA units. PCS Aurora estimated the absorber (venturi scrubber) 
would incur capital costs of approximately $270,500, based on prior 
absorber purchases for its facility. We estimated annual costs of 
approximately $95,000. The costs associated with this change are 
discussed further in the memorandum ``Control Costs and Emissions 
Reductions for Phosphoric Acid and Phosphate Fertilizer Production 
Source Categories--Final Rule,'' which is available in Docket ID No. 
EPA-HQ-OAR-2012-0522.
    The definition of oxidation reactor in the final rule for NESHAP 
subpart AA has been revised to clarify that oxidizing agents may 
include: Nitric acid, ammonium nitrate, or potassium permanganate. The 
words ``or step'' has also been added to the definition of oxidation 
reactor, for instances when a facility may not typically identify their 
oxidation process as occurring in a reactor. The definition now states 
that ``oxidation reactor means any equipment or step that uses an 
oxidizing agent (e.g., nitric acid, ammonium nitrate, or potassium 
permanganate) to treat SPA.'' Similarly, the definition of ``SPA 
plant'' in the final rule for NSPS subpart U has also been revised to 
reflect these changes.
    ii. Defluorination and Clarifiers--Comment. Many commenters opposed 
the proposed expanded definition of ``wet-process phosphoric acid 
line'' to include ``clarifiers'' and ``defluorination processes.'' 
These commenters stated that the proposed revisions have the potential 
to pull in several ``defluorination processes'' and ``clarifiers'' that 
are not subject to the current rule (e.g., animal feed phosphate 
production operations that have traditionally been outside the scope of 
this subpart). These commenters argued that any unit operation that 
conducts evaporation or concentrates phosphoric acid will have the 
effect of defluorinating to some extent. One of these commenters stated 
that they have a desulfation process at one of their facilities that 
reduces F; the commenter also said that this facility's WPPA process 
line has several filter product tanks, evaporator feed tanks, and 
evaporator product tanks that could potentially be deemed clarifiers, 
and thus be pulled into the proposed rule. Another of these commenters 
argued that it is not logical to include clarifier and defluorination 
systems in the definition because they operate independently of process 
lines, and are often operated when feed is not put into process lines 
(and so are not a process line manufacturing phosphoric acid by 
reacting phosphate rock and acid). This commenter added that clarifiers 
often operate more like tanks than process equipment and are not 
routinely emptied; and emissions from clarifiers are not a function of 
phosphate feed material to the reactor. The commenter stated that the 
addition of clarifiers will require significant facility modifications 
to accommodate emissions testing because although some clarifiers are 
evacuated to WPPA scrubbers, others are not; and even though some 
clarifiers have independent evacuation and scrubbing systems, other 
clarifiers have no evacuation and scrubbing systems. Another commenter 
also stated that one of their facilities contains clarifiers that are 
not source tested or vented to a wet scrubber. This commenter stated 
that it was not possible for one of their facilities to determine 
whether they meet the proposed standard for a WPPA process line that 
includes defluorination processes because their defluorination units 
are not only integrated with their WPPA process, but also with 
processes that do not meet the definition of WPPA lines. A commenter 
added that defluorination processes and clarifiers are often subject to 
separate emissions control requirements in their title V permits.
    Two commenters stated that since the original rule was adopted, the 
definition of ``wet-process phosphoric line'' has not been interpreted 
to extend or apply to clarifiers or defluorination processes. One of 
these commenters claimed that the only rationale the EPA provides is 
that the rules were ``initially intended'' to cover these sources, but 
argued that neither the original proposal, nor the original final rule 
mentioned the term ``clarifier'' or ``defluorination process.'' The 
commenters requested that the EPA conduct CAA section 112(d)(2) or 
112(d)(3) analyses for these new affected units. If the EPA conducts 
these analyses, and decides to expand the definition of ``wet-process 
phosphoric acid line'' to include ``clarifiers'' and ``defluorination 
processes,'' a commenter suggested that the definition exclude units 
that partially clarify or defluorinate an in-process stream 
incidentally.
    Response. Based on information in process flow diagrams provided by 
facilities, we initially believed that clarifiers and defluorination 
systems were part of the WPPA process lines that would have been 
considered in the original MACT analysis, and, thus, subject to the 
existing limits. However, the EPA agrees that clarifiers and 
defluorination systems should not be included in the WPPA process line 
definition of NESHAP subpart AA, based on the new information 
available. We also agree that clarifiers and defluorination systems 
should not be included in the WPPA plant definition of NSPS subpart T.
    In the proposed rules, the EPA was specifically referring to 
defluorination

[[Page 50418]]

processes that use diatomaceous earth and are included as part of the 
WPPA process line; however, commenters explained that this type of 
process is used solely in animal feed production. Because 
defluorination processes that use diatomaceous earth are not related to 
phosphoric acid manufacturing, as we first surmised, it is not 
appropriate to include defluorination processes in the WPPA process 
line definition.
    In response to comments regarding the inclusion of clarifiers in 
the WPPA process line definition, we searched historical data. 
Specifically, we reviewed the 1996 memorandum ``National Emission 
Standards for Hazardous Air Pollutants from Phosphoric Acid 
Manufacturing and Phosphate Fertilizers Production; Proposed Rules--
Draft Technical Support Document and Additional Technical Information'' 
(1996 TSD) to determine if clarifier emissions were included in the 
MACT floor evaluation for WPPA process lines (the 1996 TSD is item II-
B-20 in Docket A-94-02). The 1996 TSD lists, in Attachment 2, the WPPA 
test data that were assembled for the MACT floor analysis. Based on 
this review, we were not able to confirm that clarifiers were included 
as part of the WPPA emissions dataset that was evaluated in order to 
conduct the MACT floor analysis; therefore, we are not including 
clarifiers in the WPPA process line definition. Similarly, we are not 
including clarifiers in the WPPA plant definition of NSPS subpart T.
    iii. Generic Process Line Definition--Comment. One commenter stated 
that the EPA has introduced ambiguity and vagueness with its definition 
of a generic ``process line'' that includes ``all equipment associated 
with the production of any grade or purity of a phosphoric acid product 
including emission control equipment.'' The commenter asserted that 
under this expansive definition, every hypothetical fugitive emission 
source would have to be accounted for in determining compliance. The 
commenter explained that the EPA has not collected emission data from 
``all equipment'' nor provided guidance on estimating emissions for 
such sources in order to allow entities with process lines to 
demonstrate compliance. The commenter stressed the ``process line'' 
definition, as it currently stands, could include a wash plant that 
prepares phosphate ore or product storage tanks due to these sources 
being considered ``associated'' with production and thus subject to the 
proposed NESHAP.
    Response. The Agency agrees with the commenter that it is not 
necessary to include the generic ``process line'' definition, and has 
removed it from the NESHAP subpart AA final rule. This definition did 
not provide additional clarity to facilities, and it was not our intent 
to include emissions from ``all equipment'' that is ``associated'' with 
phosphoric acid production for compliance determinations. Specific 
definitions are provided for WPPA process line, SPA process line, and 
PPA process line and, therefore, enough specificity is already provided 
in the rule.
    iv. ``Includes, but is Not Limited to''--Comment. A commenter 
remarked that incorporating the language ``includes, but is not limited 
to'' in the definitions of WPPA, SPA, and PPA process lines is overly 
broad and creates ambiguity. They stated that industry should have 
certainty as to the applicability and scope of the rule, but the 
language ``includes, but is not limited to'' creates uncertainty as to 
where the affected equipment begins and ends for purposes of 
demonstrating compliance.
    Response. We agree that this language creates overly broad process 
line definitions and can lead to regulatory uncertainty for affected 
sources. Therefore, we are not finalizing the language ``includes, but 
is not limited to'' in the definitions of WPPA, SPA, and PPA process 
lines of NESHAP subpart AA. Similarly, we are not finalizing the 
language ``includes, but is not limited to'' in the definitions of WPPA 
plant and SPA plant of NSPS subpart T and NSPS subpart U, respectively.
    b. Testing, Monitoring, Recordkeeping and Reporting--i. Pressure 
Drop Across Absorber--Comment. Several commenters requested the EPA 
delete the requirement that pressure drop across an absorber must be 
greater than 5 inches of water in order to use the option of measuring 
pressure drop as an operating parameter. These commenters contended 
that the EPA has not articulated any basis for the requirement. These 
commenters provided data demonstrating that units operate in compliance 
with the emission standards when the pressure drop across an absorber 
is less than 5 inches of water. One of these commenters expressed 
safety concerns associated with operating scrubbers at higher range 
pressure drop settings, citing one of its facilities that experienced 
the entrainment of moisture within the absorbing tower when operating 
at pressure drops in excess of 8 inches of water, and another that 
experienced the buildup of excessive fumes on the digester floor when 
operating the digester scrubber as high as 6 inches of water.
    Response. The Agency maintains its determination that pressure drop 
is not an appropriate monitoring parameter for absorbers that do not 
use the energy from the inlet gas to increase contact between the gas 
and liquid in the absorber (see ``Use of Pressure Drop as an Operating 
Parameter,'' which is available in Docket ID No. EPA-HQ-OAR-2012-0522). 
Therefore, we are not revising this proposed amendment.
    High-energy (i.e., high pressure drop) absorbers, such as venturi 
scrubbers, are designed to use the energy in the inlet gas to atomize 
the liquid stream entering the absorber which increases the contact 
between the liquid droplets and gas. For these types of absorbers, 
pressure drop is an appropriate monitoring parameter because changes in 
pressure drop values indicate that either liquid droplets are not being 
formed effectively inside the absorber (falling pressure drop), or that 
the absorber is fouled (increasing pressured drop). Pressure drop is 
not an appropriate monitoring parameter for low-energy absorbers (i.e., 
absorbers that are designed to operate with pressure drops of 5 inches 
of water column or less) because pressure drop is not integral to the 
mechanism used in the absorber to mix the scrubbing liquid and inlet 
gas. Furthermore, in a meeting that occurred after the public comment 
period closed (see ``EPA Meeting Minutes for TFI Discussion March 12, 
2015,'' which is available in Docket ID No. EPA-HQ-OAR-2012-0522), 
industry stated that there is no correlation between pressure drop and 
absorber performance.
    With regard to the safety concerns raised by one commenter when 
operating low-energy absorbers at high pressure drop settings, the 
proposed rule (NESHAP subpart AA) did not require low-energy absorbers 
(i.e., absorbers that are designed to operate with pressure drops of 5 
inches of water column or less) to operate at pressure drops greater 
than 5 inches of water column. Instead, the proposed rule required a 
different parameter to be monitored for these types of absorbers. 
Nevertheless, based on other comments received, we are not adopting the 
proposed monitoring for low-energy absorbers, and have revised the 
final rule (NESHAP subpart AA) to require liquid-to-gas ratio 
monitoring for low-energy absorbers in lieu of monitoring influent 
liquid flow and pressure drop through the absorber (see section 
V.F.3.b.ii of this preamble for further details).
    ii. Absorber Monitoring Options--Comment. Several commenters called 
attention to the options of either measuring: (1) The temperature at 
the

[[Page 50419]]

wet scrubber gas stream outlet and pressure at the liquid inlet of the 
absorber, or (2) the temperature at the scrubber gas stream outlet and 
scrubber gas stream inlet. One of these commenters said that they do 
not believe monitoring gas temperature in locations of large ambient 
temperature ranges would provide accurate monitoring of the absorbers 
performance. The commenter argued that temperature and pressure probes 
would be very susceptible to scaling issues. In addition, this 
commenter contended that liquid inlet pressure does not provide any 
additional monitoring of the absorber performance, since the inlet 
liquid flow rate is already measured and monitored. Another commenter 
contended that the EPA has not provided any data or analysis to show 
that there is a correlation between temperature and emissions; the 
commenter stated that they were not aware of any data suggesting a 
relationship between exit temperature and emissions, or that monitoring 
temperature difference across an absorber would be effective. One of 
these commenters argued that they were not in a position to evaluate 
the difficulties associated with performing the associated monitoring 
and establishing the requisite operating ranges.
    Response. Absorber outlet gas temperature is often used to indicate 
a change in operation for absorbers that are used to control thermal 
processes. Because this source category uses the wet process in lieu of 
a thermal process to produce phosphoric acid, the Agency agrees with 
the commenters that temperature is not an appropriate monitoring 
parameter for absorbers used in this source category, and has removed 
these monitoring options from Table 3 of the final rule (NESHAP subpart 
AA). However, in light of this comment, the Agency has revised Table 3 
of NESHAP subpart AA to require liquid-to-gas ratio monitoring for low-
energy absorbers (i.e., absorbers that are designed to operate with 
pressure drops of 5 inches of water column or less) in lieu of 
monitoring influent liquid flow and pressure drop through the absorber. 
(See section V.F.3.b.i of this preamble for further details of why we 
are not allowing pressure drop monitoring for low-energy absorbers.) 
Although liquid flow to the absorber is the most critical parameter for 
monitoring absorption systems, monitoring the inlet gas flow rate along 
with the influent liquid flow rate (and determining liquid-to-gas 
ratio) provides better indication of whether enough water is present to 
provide adequate scrubbing for the amount of gas flowing through the 
system. Furthermore, the Agency has revised Table 3 of NESHAP subpart 
AA to require influent liquid flow and pressure drop monitoring for 
high-energy (i.e., high pressure drop) absorbers, such as venturi 
scrubbers; and we are keeping liquid-to-gas ratio monitoring as an 
option for high-energy absorbers in the final rule. Rather than 
calculating one minimum flow rate at maximum operating conditions that 
must be continuously adhered to, this alternative provision (i.e., 
liquid-to-gas ratio monitoring for high-energy absorbers) allows a 
facility to optimize the liquid flow for varying gas flow rates. By 
using a liquid-to-gas ratio, sources may save resources by reducing the 
liquid rate with reductions in gas flow due to periods of lower 
production rates.
    The Agency believes the cost to implement these finalized 
monitoring requirements is minimal for facilities. For low-energy 
absorbers, we are allowing the gas stream to be measured by either 
measuring the gas stream flow at the absorber inlet or using the design 
blower capacity, with appropriate adjustments for pressure drop. 
Therefore, facilities would not need to purchase new equipment to 
measure gas flow at the inlet of the absorber since they may choose to 
use design blower capacity. Furthermore, we are not requiring any new 
monitoring for high-energy absorbers; therefore, these facilities are 
already equipped to monitor as required in the final rule.
    iii. Operating Range Established From a Previous Test--Comment. One 
commenter stated that 40 CFR 63.607(a) is somewhat ambiguous, tending 
to suggest that affected facilities would be immediately required to 
implement new equipment operating ranges following a source test, even 
if operating conditions from previous source tests demonstrated 
compliance with fluoride emission standards. The commenter argued that 
there is no reason that a new performance test at a new operating range 
should invalidate a previous performance test at a different operating 
range.
    Response. The Agency has clarified in the final rule at 40 CFR 
63.607(a) that during the most recent performance test, if owners or 
operators demonstrate compliance with the emission limit while 
operating their control device outside the previously established 
operating limit, then limits must be established. Owners or operators 
must establish a new operating limit based on that most recent 
performance test and notify the Administrator that the operating limit 
changed based on data collected during the most recent performance 
test. Public comments on the 1999 rule stated that the equipment and 
control devices in these source categories are subject to harsh 
conditions that cause corrosion and scaling of the process components. 
Accordingly, the performance of the emissions controls will vary over 
time, and so might emissions. Thus, the Agency disagrees with the 
commenter's argument. We have determined that a new performance test 
conducted under a particular operating range should invalidate a 
previous operating range that was established under different operating 
conditions. An operating limit (e.g., an operating range, a minimum 
operating level, or maximum operating level) is established using the 
most recent performance test, or in certain instances, a series of 
tests (potentially including historical tests). However, in all cases, 
if owners or operators demonstrate compliance with an emission limit 
during the most recent performance test, and during this performance 
test an owner's or operator's control device was operating outside the 
previously established operating limit, the owner or operator must 
establish a new operating limit that incorporates that most recent 
performance test.
    iv. Approving Operating Ranges--Comment. Several commenters support 
the EPA's proposal to eliminate the requirement that facilities may not 
implement new operating parameter ranges until the Administrator has 
approved them, or 30 days have passed since submission of the 
performance test results. A commenter pointed out that 40 CFR 
63.605(d)(1)(iii)(B), as proposed, does not provide the 30-day default 
period for the effectiveness of the new ranges if the EPA Administrator 
does not act; therefore, as currently set forth in the proposed rule, 
sources will be left in limbo waiting for the EPA Administrator to 
respond before they can implement new ranges. A commenter suggested 
that the EPA revise the proposed regulatory language to require 
submission of the new ranges to EPA, but delete the requirement to 
request and obtain EPA's approval of the new ranges. Similarly, another 
commenter requested the EPA clarify the process for establishing new 
equipment operating ranges following source performance testing. This 
commenter contended that facilities should have the ability to update 
operating parameters if they desire based on source testing, and the 
facility should be required to submit the new

[[Page 50420]]

ranges, but not be required to obtain EPA's approval of the new ranges.
    In addition, a commenter requested that the EPA clarify how 
revising the proposed regulatory language to require submission of the 
new ranges to the EPA, but deleting the requirement to request and 
obtain EPA's approval of the new ranges, will affect possible 
obligations to undertake permit modifications of title V permits under 
40 CFR part 70. This commenter stated that such administrative 
processes are not fully anticipated in the proposed rule.
    Response. In the proposed NESHAP subpart AA, the Agency intended 
that facilities not be required to obtain approval, and, instead, 
immediately comply with a new operating limit when it is developed and 
submitted to the Administrator. Therefore, the requirements at proposed 
40 CFR 63.605(d)(1)(iii)(B) have been revised in the final rule at 40 
CFR 63.605(d)(1)(ii)(B), as the commenter requests, to remove the 
requirement that facilities must request and obtain approval of the 
Administrator for changing operating limits. Furthermore, the Agency 
suggests that the title V permit be modified as soon as the 
Administrator is notified of a change in an operating limit. The Agency 
acknowledges that corrections and modifications to permit applications 
could become a problem for a facility, particularly if the 
Administrator determines the operating limit is not appropriate after a 
facility has already applied for the change to be made in its air 
permit; however, we expect this scenario to be rare.
    c. Translation of Total Fluoride to HF Emission Limits--Comment. 
With regard to the proposed NESHAP subpart AA, several commenters 
opposed the use of EPA Method 320 to test for HF, and supported the 
retention of a total fluoride compliance standard and associated 
testing using EPA Method 13A or 13B. These commenters argued that EPA 
Method 320 leads to unreliable and unrepresentative results because 
some reactive fluoride compounds in the exhaust may form HF in the 
sampling equipment. The commenters explained that complex reactions 
leading to fluoride emissions occur not only in the processing units 
located at the Phosphoric Acid Manufacturing source category, but also 
in the scrubber systems designed to remove fluoride from the stack 
gases. Commenters stated that these reactions result in a mix of 
gaseous, aerosol, and particle bound fluoride (all three phases) in the 
stack gas, in the form of compounds like silica tetrafluoride, various 
fluorosilicate aerosols and/or droplets, ammonium fluoride, ammonium 
bifluoride, and/or ammonium fluorosilicate; and argued that these 
compounds have the potential to be captured in a Method 320 sampling 
equipment, biasing or interfering with the results of the sampling. 
Commenters specified that the EPA Method 320 sampling conducted in 
response to the EPA's information requests demonstrated that 
SiF4 readily reacts with water vapor in the stack gas 
producing HF and silicon hydroxide; and one of the commenters provided 
information showing that this reaction is dependent on temperature, 
moisture, and residence time in the sampling system. Additionally, some 
of the commenters listed technical issues that they encountered during 
the EPA Method 320 sampling that they conducted in response to EPA's 
information requests. These commenters recommended certain procedures 
be followed when conducting EPA Method 320 at the Phosphoric Acid 
Manufacturing source category; however, they also cautioned that their 
recommendations would not resolve all of the inherent problems with the 
sampling and analysis process. The commenters also expressed concern 
over the increase in testing costs from using EPA Method 320 instead of 
EPA Method 13A or 13B, citing an increase of at least 3 to 4 times when 
using EPA Method 320 instead of EPA Method 13B.
    We also received comments regarding the option to use Fourier 
transform infrared spectroscopy (FTIR) HF CEMS as a continuous 
monitoring compliance approach for HF at NESHAP subpart BB affected 
sources. One commenter contended that the EPA must consider requiring 
continuous HF emission monitoring before finalizing the proposal, and 
pointed out that there is a HF sensor (suitable for 0-10 part per 
million (ppm) monitoring range and a 0.1 ppm resolution) available for 
the Ultima X Series Gas Monitors. Several commenters opposed this 
option and cited EPA's technical memorandum ``Approach for Hydrogen 
Fluoride Continuous Emission Monitoring and Compliance Determination 
with EPA Method 320.'' They argued that the option to use FTIR HF CEMS 
exceeds the capabilities of existing technology, and that there are no 
details on the required methods to implement such a system or known 
field demonstrations of this type of system, and that the option has 
not been proven.
    Finally, one commenter requested the EPA explain its technical 
basis for abandoning the longstanding total fluoride surrogate for HF. 
The commenter argued that the EPA has established similar surrogacy 
relationships to measure HAP in other regulated source categories in 
the past.
    Response. In response to the January 2014 CAA section 114 request, 
processes at the Phosphoric Acid Manufacturing source category were 
tested for HF using EPA Method 320. Based on those results, the Agency 
concluded that moving to a form of the standard that requires HF (the 
target HAP) to be measured (but retaining the same numeric values as 
the current total fluoride standards) would be achievable by all 
facilities. However, in light of information provided by commenters, 
the Agency has re-evaluated the proposed revision to the standard and 
determined that EPA Method 320 is not an appropriate test method for 
accurately measuring HF emissions from process lines in this specific 
source category due to the complex and often incomplete chemical 
reactions with silicon compounds in these sources. Accordingly, the 
Agency is not adopting the proposed HF standards in NESHAP subpart AA. 
The Agency has determined that SiF4 and water are naturally 
present in the exhaust gases of the processes located at the Phosphoric 
Acid Manufacturing source category; and these chemical compounds will 
react to form HF and silicon dioxide in the near field from the 
emission point on release into the atmosphere. The Agency has reviewed 
a study \10\ stating that the equilibrium of this chemical reaction is 
highly dependent on temperature such that as temperature increases, the 
conversion of SiF4 to HF increases. At high sampling 
temperatures (i.e., sampling temperatures ranged from about 150 to 300 
degrees Fahrenheit during the EPA Method 320 testing conducted pursuant 
to the January 2014 CAA section 114 requests), there is nearly a 
complete conversion of SiF4 to HF. Therefore, as 
SiF4 is captured in the EPA Method 320 sampling system, it 
may react with moisture (water) to form HF, resulting in HF 
measurements from this source category that are biased. That is, due to 
the chemical interactions and reactions with moisture at different 
temperatures, some of the HF emissions detected by EPA Method 320 may 
not represent HF that exists in the exhaust stack or HF released from 
phosphoric acid production.
---------------------------------------------------------------------------

    \10\ Koogler & Associates, Inc. ``Technical Evaluation of the 
Measurement Limitations Associated with Source HF Emissions by EPA 
Method 320.'' January 21, 2015.
---------------------------------------------------------------------------

    As a result of our determination to not adopt the proposed HF 
standards, the

[[Page 50421]]

Agency has retained the current total fluoride limits (lb total F/ton 
P2O5 feed) measured using EPA Method 13A or 13B 
in NESHAP subpart AA as a surrogate for the HAP HF, rather than HF 
emission limits using EPA Method 320. Furthermore, in light of this 
conclusion, the Agency is not finalizing an option to use FTIR HF CEMS. 
In the final rule promulgated on June 10, 1999 (64 FR 31358), the EPA 
explained that total fluoride was used as a surrogate for HF to 
establish MACT for emissions from process sources because no direct 
measurements of HF were available and because the NSPS are based on 
total F. On November 7, 2014, we proposed HF emission limits in an 
attempt to base the standard on the specific HAP (HF) that is emitted 
by this source category because we concluded that new technology (EPA 
Method 320) allows for direct measurement of HF, and because it is 
preferred to measure the listed HAP directly when possible. However, in 
light of the chemical interactions that may occur at this source 
category during sample collection using EPA Method 320 (skewing HF 
testing results), we are retaining the long-standing surrogate of total 
fluoride for HF and the annual testing with EPA Method 13A or 13B. 
Results from EPA Method 13A or 13B testing include all fluoride 
compounds, including HF. Furthermore, since the control of total 
fluoride and HF from process sources at this source category is 
accomplished with the same control technology (scrubbers), the total 
fluoride emission limits will result in installation of the MACT for HF 
and the same level of HF control will be achieved regardless of how the 
emission limits are expressed. The use of total fluoride as a surrogate 
for HF simply changes the metric for compliance demonstration, not the 
actual level of emission control achieved. As such, we are retaining 
the existing total fluoride limits for all emission sources in NESHAP 
subpart AA. Although, at present time, the Agency is not finalizing HF 
standards in NESHAP subpart AA, it may be possible to do so in a future 
rulemaking with additional data and specificity on monitoring 
requirements.
4. What is the rationale for our final decisions regarding these other 
changes to the Phosphoric Acid Manufacturing NESHAP and NSPS?
    For the reasons provided above and in the preamble for the proposed 
rule, we are finalizing: The proposed requirement in NESHAP subpart AA 
that pressure drop across an absorber must be greater than 5 inches of 
water in order to use the option of measuring pressure drop as an 
operating parameter; the proposed definitions for ``superphosphoric 
acid process line'' (in NESHAP subpart AA) and ``superphosphoric acid 
plant'' (in NSPS subpart U) to include oxidation reactors; and other 
proposed clarifications and corrections.
    Additionally, for the reasons provided above, we are making the 
revisions, clarifications and corrections noted in section V.F.2 in the 
final rules for NESHAP subpart AA, NSPS subpart T, and NSPS subpart U.

VI. What is the rationale for our final decisions and amendments for 
the Phosphate Fertilizer Production source category?

    For each issue related to the Phosphate Fertilizer Production 
source category, this section provides a description of what we 
proposed and what we are finalizing for the issue, the EPA's rationale 
for the final decisions, and amendments and a summary of key comments 
and responses. For all comments not discussed in this preamble, comment 
summaries and the EPA's responses can be found in the Comment Summary 
and Response document available in the docket.

A. Residual Risk Review for the Phosphate Fertilizer Production Source 
Category

1. What did we propose pursuant to CAA section 112(f) for the Phosphate 
Fertilizer Production source category?
    Pursuant to CAA section 112(f), we conducted a residual risk review 
and presented the results of this review, along with our proposed 
decisions regarding risk acceptability and ample margin of safety, in 
the November 7, 2014, proposed rule for the Phosphate Fertilizer 
Production NESHAP (79 FR 66512). The results of the risk assessment are 
presented briefly below in Table 4 of this preamble, and in more detail 
in the residual risk document, ``Residual Risk Assessment for Phosphate 
Fertilizer Production and Phosphate Fertilizer Production Source 
Categories in support of the July 2015 Risk and Technology Review Final 
Rule,'' which is available in the docket for this rulemaking.

                                        Table 4--Human Health Risk Assessment for Phosphate Fertilizer Production
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Cancer MIR  (in 1                Population  Population  Max chronic non-cancer
                                                 million)           Cancer        with        with              HI
    Category & number  of facilities     ------------------------  incidence   risks  of   risks  of ------------------------ Worst-case max  acute non-
                 modeled                   Based on    Based on   (cases per    1-in-1      10-in-1    Based on    Based on            cancer HQ
                                            actual     allowable     year)    million or  million or    actual     allowable
                                           emissions   emissions                  more        more     emissions   emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Phosphate Fertilizer....................         0.5         0.5       0.001           0           0       0.003       0.003  HQREL = 0.4 (elemental Hg)
(11 facilities).........................                                                                                      HQAEGL-1 = 0.09
                                                                                                                               (hydrofluoric acid).
Facility-wide (11 facilities)...........         0.5  ..........       0.001           0           0         0.2  ..........  ..........................
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on actual emissions for the Phosphate Fertilizer Production 
source category, the MIR was estimated to be less than 1-in-1 million, 
the maximum chronic non-cancer TOSHI value was estimated to be up to 
0.003, and the maximum off-site acute HQ value was estimated to be up 
to 0.4. The total estimated national cancer incidence from this source 
category, based on actual emission levels, was 0.001 excess cancer 
cases per year, or one case in every 1,000 years. Based on MACT-
allowable emissions for the Phosphate Fertilizer Production source 
category, the MIR was estimated to be less than 1-in-1 million, and the 
maximum chronic non-cancer TOSHI value was estimated to be up to 0.003. 
We also found there were emissions of several PB-HAP with an available 
RTR multipathway screening value, and, with the exception of Hg 
compounds, the reported emissions of these HAP

[[Page 50422]]

(i.e., lead compounds, and cadmium compounds) were below the 
multipathway screening value for each compound. One facility emitted 
divalent Hg (Hg2+) above the Tier I screening threshold 
level, exceeding the screening threshold by a factor of 20. 
Consequently, we conducted a Tier II screening assessment for 
Hg2+. This assessment uses the assumption that the 
biological productivity limitation of each lake is 1 gram of fish per 
acre of water, meaning that in order to fulfill the adult ingestion 
rate, a fisher would need to fish from 373 total acres of lakes. The 
result of this analysis was the development of a site-specific emission 
screening threshold for Hg2+. We compared this Tier II 
screening threshold for Hg2+ to the facility's 
Hg2+ emissions. The facility's emissions exceeded the Tier 
II screening threshold by a factor of 3.
    Additionally, to refine our Hg Tier II Screen for this facility, we 
first examined the set of lakes from which the angler ingested fish. 
Any lakes that appeared to not be fishable or publicly accessible were 
removed from the assessment, and the screening assessment was repeated. 
After we made the determination the three critical lakes were fishable, 
we analyzed the hourly meteorology data from which the Tier II 
meteorology statistics were derived. Using buoyancy and momentum 
equations from literature, and assumptions about facility fenceline 
boundaries, we estimated by hour the height achieved by the emission 
plume before it moved laterally beyond the assumed fenceline. If the 
plume height was above the mixing height, we assumed there was no 
chemical exposure for that hour. The cumulative loss of chemical being 
released above the mixing height reduces the exposure and decreases the 
Tier II screening quotient. Although the refined Tier II analysis for 
Hg emissions indicated a 23-percent loss of emissions above the mixing 
layer due to plume rise, this reduction still resulted in an angler 
screening non-cancer value equal to 2.
    For this facility, after we performed the lake and plume rise 
analyses, we reran the relevant Tier II screening scenarios for the 
travelling subsistence angler in TRIM.FaTE with the same hourly 
meteorology data and hourly plume-rise adjustments from which the Tier 
II meteorology statistics were derived. The use of the time-series 
meteorology reduced the screening value further to a value of 0.6. For 
this source category our analysis indicated no potential for 
multipathway impacts of concern from this facility. The maximum 
facility-wide MIR was less than or equal to 1-in-1 million and the 
maximum facility-wide TOSHI was 0.2. We weighed all health risk factors 
in our risk acceptability determination, and we proposed that the 
residual risks from the Phosphate Fertilizer Production source category 
are acceptable.
    We then considered whether the Phosphate Fertilizer Production 
NESHAP provides an ample margin of safety to protect public health and 
prevents, taking into consideration costs, energy, safety, and other 
relevant factors, an adverse environmental effect. In considering 
whether the standards should be tightened to provide an ample margin of 
safety to protect public health, we considered the same risk factors 
that we considered for our acceptability determination and also 
considered the costs, technological feasibility and other relevant 
factors related to emissions control options that might reduce risk 
associated with emissions from the source category. We proposed that 
the current standards provided an ample margin of safety to protect 
public health. With respect to adverse environmental effects, none of 
the individual modeled concentrations for any facility in the source 
category exceeded any of the ecological benchmarks (either the LOAEL or 
NOAEL). Based on the results of our screening analysis for risks to the 
environment, we also proposed that the current standards prevent an 
adverse environmental effect.
2. How did the risk review change for the Phosphate Fertilizer 
Production source category?
    The residual risk review for the Phosphate Fertilizer Production 
source category did not change since proposal (79 FR 66512). 
Accordingly, we are not tightening the standards under section 
112(f)(2) based on the residual risk review, and are thus readopting 
the existing standards under section 112(f)(2).
3. What key comments did we receive on the risk review, and what are 
our responses?
    The comments received on the proposed residual risk review were 
generally supportive of our determination of risk acceptability and 
ample margin of safety analysis. However, we received several comments 
requesting we make changes to the residual risk review, including:

     Update the residual risk review with the 
recommendations and information from the NAS;
     Incorporate the best currently available information on 
children's exposure to lead, and go beyond using the 2008 Lead 
NAAQS;
     Reevaluate whether the residual risk review is 
consistent with the key recommendations made by the SAB;
     Clarify in the rulemaking docket that data received by 
industry were commensurate with the relevant statutory obligations;
     Revise HF emission data because they are not 
representative of actual HF emissions, but rather overestimate 
emissions causing the residual risk review to have an overly 
conservative bias;
     Reconsider the assumption used in the NESHAP residual 
risk assessment that all chromium is hexavalent chromium;
     Revise certain stack parameters used in the analysis;
     Clarify meteorological data used in the analysis;
     Adequately explain rationale for the maximum 1-hour 
emission rate used for determining potential acute exposures;
     Clarify the selection of ecological assessment 
endpoints; and
     Provide some quantitative or qualitative rationale for 
the characterization of the exposure modeling uncertainty.

    We evaluated the comments and determined that no changes were 
needed. Since none of these comments had an effect on the final rule, 
their summaries and corresponding EPA responses are not included in 
this preamble. A summary of these comments and our responses can be 
found in the Comment Summary and Response document available in the 
docket for this action (EPA-HQ-OAR-2012-0522).
4. What is the rationale for our final approach and final decisions for 
the risk review?
    For the reasons explained in the proposed rule, we determined that 
the risks from the Phosphate Fertilizer Production source category are 
acceptable, the current emissions standards provide an ample margin of 
safety to protect public health, and prevent an adverse environmental 
effect. Since proposal, neither the risk assessment nor our 
determinations regarding risk acceptability, ample margin of safety or 
adverse environmental effects have changed. Therefore, pursuant to CAA 
section 112(f)(2), we are finalizing our residual risk review as 
proposed.

B. Technology Review for the Phosphate Fertilizer Production Source 
Category

1. What did we propose pursuant to CAA section 112(d)(6) for the 
Phosphate Fertilizer Production source category?
    Pursuant to CAA section 112(d)(6), we conducted a technology 
review, which focused on identifying and evaluating developments in 
practices, processes, and control technologies for the emission sources 
in the Phosphate

[[Page 50423]]

Fertilizer Production source category. At proposal, we did not identify 
cost-effective developments in practices, processes, or control 
technologies that warrant revisions to the NESHAP for this source 
category. More information concerning our technology review can be 
found in the memorandum, ``CAA Section 111(b)(1)(B) and 112(d)(6) 
Reviews for the Phosphate Fertilizer Production and Phosphate 
Fertilizer Production Source Categories,'' which is available in the 
docket, and in the preamble to the proposed rule, 79 FR 66538-66539.
2. How did the technology review change for the Phosphate Fertilizer 
Production source category?
    The technology review for the Phosphate Fertilizer Production 
source category did not change since proposal (79 FR 66512). Therefore, 
we are not revising NESHAP subpart BB based on the technology review.
3. What key comments did we receive on the technology review, and what 
are our responses?
    Commenters agreed with our conclusion that there are no new cost-
effective developments in practices, processes, or control technologies 
that can be applied to the Phosphate Fertilizer Production source 
category that would reduce HAP emissions below current levels.
4. What is the rationale for our final approach for the technology 
review?
    For the reasons explained in the proposed rule, we concluded that 
additional standards are not necessary pursuant to CAA section 
112(d)(6); therefore, we are not finalizing changes to NESHAP subpart 
BB as part of our technology review.

C. NSPS Review for the Phosphate Fertilizer Production Source Category

    The NSPS review focused on the emission limitations that have been 
adequately demonstrated to be achieved in practice, taking into account 
the cost of achieving such reduction and any non-air quality health and 
environmental impact and energy requirements. Determining the BSER that 
has been adequately demonstrated and the emission limitations achieved 
in practice necessarily involves consideration of emission reduction 
methods in use at existing phosphate fertilizer production plants. To 
determine the BSER, the EPA performed an extensive review of several 
recent sources of information including a thorough search of the RBLC, 
section 114 data received from industry and other relevant sources.
    Our review considered the emission limitations that are currently 
achieved in practice, and found that more stringent standards are not 
achievable for this source category. When evaluating the emissions from 
various process lines, we observed differences in emissions levels, but 
did not identify any patterns in emission reductions based on control 
technology configuration. More information concerning our NSPS review 
can be found in the memorandum, ``CAA Section 111(b)(1)(B) and 
112(d)(6) Reviews for the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production Source Categories.'' Though some of the sources 
are emitting at levels well below the current NSPS, other sources are 
not. We evaluated emissions based on control technologies and practices 
used by facilities, and found that the same technologies and practices 
yielded different results for different facilities. Therefore, we 
determined that we cannot conclude that new and modified sources would 
be able to achieve a more stringent NSPS. As explained in the proposed 
rule, all Phosphate Fertilizer Production NSPS (under subpart V, 
subpart W, and subpart X) emission sources, and the control 
technologies that would be employed, are the same as those for the 
NESHAP regulating phosphate fertilizer plants, such that we reached the 
same conclusion that there are no identified developments in technology 
or practices that results in cost-effective emission reductions 
strategies. Therefore, we are finalizing our determination that 
revisions to NSPS subpart V, subpart W, and subpart X standards are not 
appropriate pursuant to CAA section 111(b)(1)(B).

D. Startup, Shutdown, and Malfunction Provisions for the Phosphate 
Fertilizer Production Source Category

1. What SSM provisions did we propose for the Phosphate Fertilizer 
Production source category?
    To address the U.S. Court of Appeals for the District of Columbia 
Circuit vacatur of portions of the EPA's CAA section 112 regulations 
governing the emissions of HAP during periods of SSM, Sierra Club v. 
EPA, 551 F.3d 1019 (D.C. Cir. 2008), we proposed to revise and add 
certain provisions to the NESHAP subpart BB. We proposed to revise the 
General Provisions table (appendix A of NESHAP subpart BB) to change 
several references related to requirements that apply during periods of 
SSM. We also proposed to add the following provisions to the rule: (1) 
Work practice standards for periods of startup and shutdown in lieu of 
numeric emission limits; (2) the general duty to minimize emissions at 
all times; (3) performance testing conditions requirements; (4) site-
specific monitoring plan requirements; and (5) malfunction 
recordkeeping and reporting requirements. These proposed changes are 
discussed in more detail in section V.E of this preamble where we 
describe these same proposed changes for NESHAP subpart AA.
2. How did the SSM provisions change for the Phosphate Fertilizer 
Production source category?
    We are finalizing the proposed work practice standards for periods 
of startup and shutdown; however, in consideration of comments received 
during the public comment period for the proposed rulemaking (as 
discussed in sections VI.D.3.a and VI.D.3.b of this preamble), we are 
making changes to this work practice in order to clarify the standard 
applies in lieu of numeric emission limits and how compliance with the 
standard is demonstrated. Additionally, as discussed in section 
VI.D.3.c of this preamble, we added definitions of ``startup'' and 
``shutdown'' to provide additional clarity regarding when startup 
begins and ends, and when shutdown begins and ends.
3. What key comments did we receive on the SSM provisions, and what are 
our responses?
    Comments were received regarding the proposed revisions to remove 
the SSM exemptions for the Phosphate Fertilizer Production source 
category, and the proposed work practice standards for periods of 
startup and shutdown. The following is a summary of some of the 
comments specific to the proposed work practice standards and our 
response to those comments. Other comments and our specific responses 
to those comments can be found in the Comment Summary and Response 
document available in the docket for this action (EPA-HQ-OAR-2012-
0522).
    a. Work Practice Standard In Place Of Emission Limits--Comment. One 
commenter argued that the EPA should specify that the proposed work 
practices for plant startup and shutdown periods apply ``in lieu of'' 
any other emission standards, and that such periods should not be 
counted for testing, monitoring, or operating parameter requirements. 
The commenter noted that the proposed rule at 40 CFR 63.622(d) requires 
the use of work practices ``to demonstrate compliance with any emission 
limits''

[[Page 50424]]

during periods of startup and shutdown. The commenter agrees with the 
EPA's conclusion that it is not feasible to apply numeric limits to 
startup and shutdown because certain variables required to calculate 
emissions would be zero during such periods. The commenter also agreed 
with the EPA that existing emission control devices would still be 
effective during periods of startup or shutdown, if activated. However, 
the commenter recommended that the rule should clarify that startup and 
shutdown events should not be required to comply with the monitoring 
and operating parameter requirements because startup and shutdown 
events generally are not representative operating conditions for other 
compliance purposes, such as emissions testing. Instead, the commenter, 
as well as a second commenter, recommended that because the startup and 
shutdown periods are not representative, the rule should only require 
that (1) All emission control devices be kept active, and (2) owners 
and operators follow the general duty to control emissions, and owners 
and operators should not be required to monitor operating parameters 
during startup and shutdown periods.
    The commenter argued that the approach in the proposed rule at 40 
CFR 63.622(d) to require the use of work practices ``to demonstrate 
compliance with any emission limits'' during periods of startup and 
shutdown is ``directly inconsistent'' with the approach that the EPA 
has applied to other source categories, where such practices clearly 
were prescribed ``in lieu of'' numeric emission limits that would 
otherwise apply. (The commenter cites, for example, 78 FR 10015, 
February 12, 2013.) According to the commenter, the EPA made it clear 
in other industries' rules that such work practice standards apply ``in 
place of'' or ``in lieu of'' numeric standards, including with respect 
to monitoring and recordkeeping requirements. (See id. at 10013 and 
10015.) The commenter argues that according to the preamble language 
cited for those other industries, ``there will no longer be a numeric 
emission standard applicable during startup and shutdown,'' and the EPA 
recognizes that ``the recordkeeping requirement must change to reflect 
the content of the work practice standard'' (Id. at 10014).
    Therefore, the commenter recommended that the EPA should clearly 
explain that work practices are not applied to ``demonstrate 
compliance'' with numeric limits under subpart BB, which the EPA 
acknowledges are ``not feasible'' for startup and shutdown periods, 
and, instead, the work practices should be written to apply ``in lieu 
of'' the numeric limits during those periods. The commenter argues that 
without this clarification, it will appear that both the numeric 
standards and the work practice standards would apply during startup 
and shutdown. The commenter suggests that this can be corrected in the 
rule by using the ``in lieu of'' language used for other industries.
    Response. The commenter is correct that our intention at proposal 
was that the numeric emission limits would not apply during periods of 
startup and shutdown, but that facilities would comply with the work 
practice instead. We did not intend for the work practice to be a 
method to demonstrate compliance with the emission limit. We are 
replacing the phrasing ``to demonstrate compliance'' with ``in lieu 
of'' as this language is more consistent with our original intent. 
Accordingly, in the final rule, 40 CFR 63.622(d) specifies that the 
emission limits of 40 CFR 63.622(a) do not apply during periods of 
startup and shutdown. Instead, owners and operators must follow the 
work practice specified in 40 CFR 63.622(d). See section VI.D.3.b of 
this preamble for our response to commenters argument that owners and 
operators should not be required to monitor operating parameters during 
startup and shutdown periods.
    b. Applicability of Operating Limits--Comment. Two commenters 
recommended that the EPA amend the rule to make clear that the work 
practice standards for startup and shutdown also apply in lieu of the 
parametric monitoring requirements set forth in NESHAP subpart BB and 
make explicit that parametric operating requirements do not apply 
during times of startup and shutdown.
    One commenter argued that when the EPA established the flow rate 
and pressure drop parametric monitoring requirements in its 1999 final 
rule, the EPA concluded that requiring continuous monitoring of these 
parameters ``help[ed] assure continuous compliance with the emission 
limit'' (64 FR 31365, June 10, 1999). The commenter also asserted that 
the rule specifies that ``[t]he emission limitations and operating 
parameter requirements of this subpart do not apply during periods of 
startup, shutdown, or malfunction . . . '' (40 CFR 63.620(e)). The 
commenter argued that this was a reasonable action because the 
operating parameter ranges are established during annual performance 
tests, and these tests cannot be performed during startup and shutdown 
conditions.
    The commenter suggested that in the proposed rule, the EPA exempted 
compliance with the emission limits during startup and shutdown 
periods, imposed work practice standards in lieu thereof, and retained 
the prohibition on conducting a performance test during periods of 
startup or shutdown (79 FR 66582 (proposed 40 CFR 63.626(d)). The 
commenter suggested that the proposed rule is silent on the 
applicability of the parametric monitoring requirements during startup 
and shutdown. The commenter asserted that because the parametric 
monitoring provisions provide an inference of compliance with the 
emission limits (64 FR 31365, June 10, 1999), and these emission limits 
do not apply during startup and shutdown, the commenter concluded that 
the parametric monitoring provisions similarly should not apply during 
startups and shutdowns.
    The commenters pointed to two recent EPA NESHAP rulemakings to 
support their conclusion. First, the commenters argued that in its 
industrial, commercial and institutional boilers and process heaters 
NESHAP reconsideration proposal (hereinafter, the ``Boiler NESHAP''), 
the EPA, responding to a comment soliciting clarification ``that the 
operating limits and opacity limits do not apply during periods of 
startup and shutdown,'' stated that with the finalization of work 
practice standards, ``EPA agrees that the requested clarification is 
what was intended in the final rule'' (76 FR 80598 and 80615, December 
23, 2011.) The commenters asserted that to this end, in its response to 
the reconsideration, the EPA made clear that affected sources must 
comply with ``all applicable emissions and operating limits at all 
times the unit is operating except for periods that meet the 
definitions of startup and shutdown in this subpart, during which times 
you must comply with these work practices'' (78 FR 7138 and 7142, 
January 31, 2013.) The commenters noted that in the Boiler NESHAP, the 
EPA required the implementation of work practice standards in lieu of 
compliance with the operating parameter requirements during startup and 
shutdown by (1) Excluding periods of startup and shutdown from the 
averaging period (Id. at 7187, 40 CFR 63.7575, the definition of a 30-
day rolling average'' excludes ``hours during startup and shutdown''), 
and (2) expressly stating that the ``standards'' (the emission limits 
and operating requirements) do not apply during periods of startup or 
shutdown. (Id. at 7163, 40 CFR 63.7500(f), titled ``What emission 
limitations, work

[[Page 50425]]

practice standards, and operating limits must I meet?'' applies ``at 
all times the affected unit is operating, except during periods of 
startup and shutdown during which time you must comply only with Table 
3 of this subpart'').
    Second, the commenters argued that in its Portland Cement NESHAP, 
the EPA specified an operating limit for kilns, identified as a 
temperature limit established during a performance test, and that the 
temperature limit applied at all times the raw mill is operating, 
``except during periods of startup and shutdown'' (78 FR 10039, 
February 12, 2013, 40 CFR 63.1346(a)(1).) Further, for the continuous 
monitoring requirements, including operating limits, the Portland 
Cement NESHAP required operating of the monitoring system at all times 
the affected source is operating, ``[e]xcept for periods of startup and 
shutdown'' (Id. at 10041, 40 CFR 63.1348(b)(1)(ii).)
    The commenters argued that given the EPA's conclusion in the 
Proposed Rule that the emission limits should not apply during startup 
and shutdown, and because the parametric monitoring requirements are 
established during a performance test (which cannot be performed during 
a startup or a shutdown) and used to infer compliance with the emission 
limits, the EPA should make clear in the final rule that the operating 
parameters requirements do not apply during a startup or a shutdown. 
The commenter recommended that the EPA should make this explicit: (1) 
In the operating and monitoring requirement section of subpart BB 
(proposed 40 CFR 63.625), and (2) by defining the averaging period 
(currently daily) as excluding periods of startup and shutdown 
(Proposed 40 CFR part 63, subpart BB, Table 4). As an alternative, the 
commenters recommended that if the EPA continues to require compliance 
with the parametric monitoring requirements during startup and shutdown 
periods, then the EPA should adopt a longer averaging period, from 
daily to 30 days, to allow for the effects of startups and shutdowns to 
be reduced by a longer period of steady-state operations. The commenter 
noted that the Boiler NESHAP has a 30-day averaging period for pressure 
drop and liquid flow rate, and excludes periods of startup and shutdown 
from the averaging period (40 CFR 63.7575, definition of ``30-day 
rolling average'' and 40 CFR part 63, subpart DDDDD, Table 4). The 
commenter stated that a 30-day averaging period would be substantially 
more stringent than the Boiler NESHAP approach since it would include 
periods of startup and shutdown, while at the same time avoid 
misleading ``exceedances'' caused by the inclusion of periods of 
startup and shutdown compared to daily average parametric limits.
    Response. We disagree with the commenters about the applicability 
of the operating limits. Based on these comments, we have clarified in 
the final rule at 40 CFR 63.622(d) that to comply with the work 
practice during periods of startup and shutdown, facilities must 
monitor the operating parameters specified in Table 3 to subpart BB and 
comply with the operating limits specified in Table 4 of subpart BB. 
The purpose of the work practice is to ensure that the air pollution 
control equipment that is used to comply with the emission limit during 
normal operations is operated during periods of startup and shutdown. 
Monitoring of control device operating parameters is necessary to 
demonstrate compliance with the work practice. We have concluded that 
it is reasonable for the control device at phosphate fertilizer 
production processes to meet the same operating limits during startup 
and shutdown that apply during normal operation, and that it is not 
necessary to specify different averaging times for periods of startup 
and shutdown. Meeting the operating limits of Table 4 of subpart BB 
will ensure that owners and operators meet the General Duty requirement 
to operate and maintain the affected source and associated air 
pollution control equipment in a manner consistent with safety and good 
air pollution control practices for minimizing emissions.
    The analogies that the commenters made to the Boiler NESHAP and the 
Portland Cement NESHAP are not relevant to this rulemaking. In each 
rulemaking, we consider the feasibility of applying standards during 
startup and shutdown based on relevant process considerations for each 
source category, the pollutants regulated, and control devices on which 
the rule is based. In developing this rule, we obtained information on 
the operation of control devices during startup and shutdown periods in 
the CAA section 114 survey issued to the phosphate fertilizer 
production industry. Based on survey results, we concluded that for 
this source category, control devices (i.e., absorbers) could be 
operated during periods of startup and shutdown. We found no indication 
that process operations during startup and shutdown would interfere 
with the ability to operate the relevant control devices according to 
good engineering practice. Moreover, the commenters provided no 
technical justification as to why a different operating limit is needed 
during startup and shutdown.
    Regarding the comparison to the industrial boiler NESHAP, the 
operation of boilers and their associated control devices are different 
than phosphate fertilizer production plants. While boiler control 
devices do not have to comply with specific operating limits during 
startup or shutdown, they must meet a work practice that includes 
firing clean fuels, operating relevant control devices (e.g., 
absorbers) as expeditiously as possible, and monitoring the applicable 
operating parameters (e.g., flow rate) to demonstrate that the control 
devices are being operated properly. The EPA currently is reconsidering 
the control requirements for industrial boilers during startup and 
shutdown (80 FR 3090, January 21, 2015). In the proposed action on 
reconsideration, we pointed out that some of the control devices used 
for boilers cannot be operated during the full duration of startup and 
shutdown because of safety concerns and the possibility of control 
equipment degradation due to fouling and corrosion. The control devices 
used for phosphate fertilizer production do not pose these same risks. 
Likewise, the fact that the Portland Cement NESHAP does not require 
monitoring of kiln temperature during startup and shutdown is not 
relevant. The Portland Cement NESHAP requires maintaining a kiln 
temperature as part of the MACT operating limit. The operating limit 
for Portland Cement does not apply during startup and shutdown because 
it is not physically possible to maintain a constant temperature during 
startup and shutdown of a kiln. In contrast, the feasibility of 
operating the control devices used to control HAP emissions from 
phosphate fertilizer production is not limited by specific process 
operating conditions. Therefore, it is feasible to operate the devices 
during startup and shutdown, and we have determined that it is 
reasonable to do so considering cost, nonair health and environmental 
impacts, and energy requirements.
    c. Definition of Startup and Shutdown--Comment. Several commenters 
stated that it is not feasible to base the conclusion of a ``shutdown'' 
on the point at which all feed has ``been processed.'' Instead, they 
suggested that the EPA should clarify the work practice standard of 
keeping all emission control equipment active during shutdowns. The 
commenters reported that facilities in the industry consider the 
commencement of ``shutdown'' as the moment at which the plant ceases 
adding feed to the affected process, rather than basing shutdown on 
when

[[Page 50426]]

all feed materials have been processed through the process. The 
commenters recommended that the EPA should define ``shutdown'' to begin 
when the facility ceases adding feed to an affected process line, and 
to conclude when the affected process line equipment is deactivated, 
even though some feed or residues may still be present within 
particular parts of the process.
    One of the commenters also noted that it is common practice to have 
short-term shutdown of process inputs for temporary maintenance work 
(including work on emission control equipment) where the entire system 
is not emptied. In these cases, feed of phosphoric acid and ammonia to 
the process is suspended as is flow from the reactor to the granulator. 
The commenter argued that because the source of fluoride to the system 
has ceased and dust generating material flows are suspended, there 
should be no significant source of emissions to control, and it is not 
necessary to require the utilization of control devices until all feed 
material has been processed. Instead, the commenter recommended that an 
affected entity should be allowed to turn off control devices when 
reactor and granulator feeds have been stopped, unless the system is 
being emptied, in which case control devices should be required as long 
as the material handling system is in operation.
    Response. We agree with the commenters that the rule needs to have 
a more precise definition of startup and shutdown that more clearly and 
reasonably establishes the times when the work practice applies and 
when the emission limits apply. Accordingly, we added a definition of 
``startup'' and ``shutdown'' in the Definitions section of the final 
rule to specify when startup begins and ends, and when shutdown begins 
and ends.
    Based on additional information provided by industry (see ``Email 
Correspondence Received After Comment Period re Startup Shutdown (May 
5, 2015),'' which is available in Docket ID No. EPA-HQ-OAR-2012-0522), 
we are including a definition of startup in the final rule. The final 
rule defines startup as commencing when any feed material is first 
introduced into an affected source and ends when feed material is fully 
loaded into the affected source. Regarding shutdown, we agree with the 
commenters that it is not feasible to process all feed material from a 
process prior to shutting down most equipment at a facility. Such 
requirement would imply that the control device must be operated after 
the shutdown ends. The final rule defines shutdown as commencing when 
the facility ceases adding feed to an affected source and ends when the 
affected source is deactivated, regardless of whether feed material is 
present in the affected source. This definition will address concerns 
about temporary shutdowns as well as shutdowns of longer duration.
    In addition, the final rule at 40 CFR 63.622(d) specifies that any 
control device used at the affected source must be operated during the 
entire period of startup and shutdown, and must meet the operating 
limits in Table 4 of the rule.
4. What is the rationale for our final decisions for the SSM 
provisions?
    For the reasons provided above and in the preamble for the proposed 
rule, we are finalizing the proposed revisions to the General 
Provisions table (appendix A of NESHAP subpart BB) to change several 
references related to requirements that apply during periods of SSM. 
For these same reasons, we are also finalizing the addition of the 
following proposed provisions to NESHAP subpart BB: (1) Work practice 
standards for periods of startup and shutdown in lieu of numeric 
emission limits; (2) the general duty to minimize emissions at all 
times; (3) performance testing conditions requirements; (4) site-
specific monitoring plan requirements; and (5) malfunction 
recordkeeping and reporting requirements.

E. Other Changes Made to the Phosphate Fertilizer Production NESHAP and 
NSPS

1. What other changes did we propose for the Phosphate Fertilizer 
Production NESHAP and NSPS?
    a. Clarifications to Applicability and Certain Definitions --i. 
NESHAP Subpart BB. As stated in the preamble to the proposed rule, to 
ensure the emission standards reflect inclusion of HAP emissions from 
all sources in the source category, we proposed to clarify the 
applicability of the NESHAP to include reaction products of ammonia and 
phosphoric acid, and not just diammonium and monoammonium phosphate.
    For consistency between NESHAP subpart AA and NESHAP subpart BB, we 
also proposed conditions in NESHAP subpart BB that exclude (like NESHAP 
subpart AA does) the use of evaporative cooling towers for any liquid 
effluent from any wet scrubbing device installed to control HF 
emissions from process equipment. Lastly, we proposed to amend the 
definitions of ``diammonium and/or monoammonium phosphate process 
line,'' ``granular triple superphosphate process line,'' and ``granular 
triple superphosphate storage building'' to include relevant emission 
points, and to remove text from the applicability section that is 
duplicative of the revised definitions.
    ii. NSPS Subpart V. We did not propose changes to applicability or 
definitions in NSPS subpart V.
    iii. NSPS Subpart W. We proposed changing the word ``cookers'' as 
listed in 40 CFR 60.230(a) to ``coolers'' in order to correct the 
typographical error.
    iv. NSPS Subpart X. We did not propose changes to applicability or 
definitions in NSPS subpart X.
    b. Testing, Monitoring, Recordkeeping and Reporting--i. NESHAP 
Subpart BB. As stated in the preamble to the proposed rule, to provide 
flexibility, we proposed several monitoring options, including pressure 
and temperature measurements, as alternatives to monitoring of absorber 
differential pressure. We also proposed monitoring the absorber inlet 
gas flow rate along with the influent absorber liquid flow rate (and 
determining liquid-to-gas ratio) in lieu of monitoring only the 
absorber inlet liquid flow rate.
    In addition, we proposed removing the requirement that facilities 
may not implement new operating parameter ranges until the 
Administrator has approved them, or 30 days have passed since 
submission of the performance test results. We proposed that facilities 
must immediately comply with new operating ranges when they are 
developed and submitted; and new operating ranges must be established 
using the most recent performance test conducted by a facility, which 
allows for changes in control device operation to be appropriately 
reflected.
    We also proposed monitoring requirements for fabric filters in 
NESHAP subpart BB because we identified two processes that used fabric 
filters rather than wet scrubbing as control technology.
    As stated in the preamble to the proposed rule, we modified the 
language for the conditions under which testing must be conducted to 
require that testing be conducted at ``maximum representative operating 
conditions'' for the process.\11\
---------------------------------------------------------------------------

    \11\ Based on the EPA memorandum, ``Issuance of the Clean Air 
Act National Stack Testing Guidance,'' dated April 27, 2009.
---------------------------------------------------------------------------

    In keeping with the general provisions for CMS (including CEMS and 
CPMS), we proposed the addition of a site-specific monitoring plan and 
calibration requirements for CMS. Provisions were also proposed that 
included electronic reporting of stack test data. We also

[[Page 50427]]

proposed modifying the format of NESHAP subpart BB to reference tables 
for emissions limits and monitoring requirements.
    Finally, we proposed HF standards in NESHAP subpart BB by 
translating the current total fluoride limits (lb total F/ton 
P2O5 feed) into HF limits (lb HF/ton 
P2O5 feed). To comply with HF standards, we 
proposed that facilities use EPA Method 320.
    ii. NSPS Subpart V. We proposed new monitoring and recordkeeping 
requirements for any granular diammonium phosphate plant that commences 
construction, modification or reconstruction after November 7, 2014 to 
ensure continuous compliance with the standard. As stated in the 
preamble to the proposed rule, to ensure that the process scrubbing 
system is properly maintained over time; ensure continuous compliance 
with standards; and improve data accessibility, we proposed the owner 
or operator establish an allowable range for the pressure drop through 
the process scrubbing system. We also proposed that the owner or 
operator keep records of the daily average pressure drop through the 
process scrubbing system, and keep records of deviations.
    For consistency with terminology used in the associated NESHAP 
subpart BB, we proposed changing the term ``scrubbing system'' to 
``absorber'' in NSPS subpart V.
    iii. NSPS Subpart W. We proposed new monitoring and recordkeeping 
requirements for any TSP plant that commences construction, 
modification or reconstruction after November 7, 2014 to ensure 
continuous compliance with the standard. As stated in the preamble to 
the proposed rule, to ensure that the process scrubbing system is 
properly maintained over time; ensure continuous compliance with 
standards; and improve data accessibility, we proposed the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. We also proposed that the owner or operator 
keep records of the daily average pressure drop through the process 
scrubbing system, and keep records of deviations.
    For consistency with terminology used in the associated NESHAP 
subpart BB, we proposed changing the term ``process scrubbing system'' 
to ``absorber'' in NSPS subpart W.
    iv. NSPS Subpart X. We proposed new monitoring and recordkeeping 
requirements for any GTSP storage facility that commences construction, 
modification or reconstruction after November 7, 2014 to ensure 
continuous compliance with the standard. As stated in the preamble to 
the proposed rule, to ensure that the process scrubbing system is 
properly maintained over time; ensure continuous compliance with 
standards; and improve data accessibility, we proposed the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. We also proposed that the owner or operator 
keep records of the daily average pressure drop through the process 
scrubbing system, and keep records of deviations.
    For consistency with terminology used in the associated NESHAP 
subpart BB, we proposed changing the term ``process scrubbing system'' 
to ``absorber'' in NSPS subpart X.
2. How did the provisions regarding these other proposed changes to the 
Phosphate Fertilizer Production NESHAP and NSPS change since proposal?
    a. Clarifications to Applicability and Certain Definitions--i. 
NESHAP Subpart BB. In consideration of comments received during the 
public comment period for the proposed rulemaking, we are defining 
``phosphate fertilizer process line'' and ``phosphate fertilizer 
production plant'' separately as discussed in section VI.E.3.a.i of 
this preamble. We are also revising rule language at 40 CFR 
63.620(b)(1), 63.622(a), 63.622(a)(1), 63.622(a)(2), 63.625(a), 
63.626(f), in Table 1, and in Table 2 to accommodate this change. We 
are also removing the proposed language ``includes, but is not limited 
to'' in the definition of DAP and/or MAP process line for reasons 
discussed in section VI.E.3.a.ii of this preamble.
    ii. NSPS Subpart V. We are not making changes to applicability or 
definitions in NSPS subpart V.
    iii. NSPS Subpart W. We are not making changes to applicability or 
definitions in NSPS subpart W.
    iv. NSPS Subpart X. We are not making changes to applicability or 
definitions in NSPS subpart X.
    b. Testing, Monitoring, Recordkeeping and Reporting.--i. NESHAP 
Subpart BB. We have not made any changes to our proposed determination 
that pressure drop is not an appropriate monitoring parameter for 
absorbers that are designed to operate with pressure drops of 5 inches 
of water column or less. However, in consideration of comments received 
during the public comment period for the proposed rulemaking, we are 
not adopting the proposed options to monitor: (1) The temperature at 
the wet scrubber gas stream outlet and pressure at the liquid inlet of 
the absorber, or (2) the temperature at the scrubber gas stream outlet 
and scrubber gas stream inlet. Instead, we have revised Table 3 of 
NESHAP subpart BB to require liquid-to-gas ratio monitoring for low-
energy absorbers, and influent liquid flow and pressure drop monitoring 
for high-energy absorbers; and we are keeping liquid-to-gas ratio 
monitoring as an option for high-energy absorbers in the final rule. 
(See sections VI.E.3.b.i and VI.E.3.b.ii of this preamble for details.)
    In addition to these revisions, we are making corrections at 40 CFR 
63.627(a) to clarify the procedures for establishing a new operating 
limit based on the most recent performance test. We are also revising 
the requirements at 40 CFR 63.625(d)(1)(ii)(B) to remove the 
requirement that facilities must request and obtain approval of the 
Administrator for changing operating limits. (See section VI.E.3.b.iv 
and VI.E.3.b.v of this preamble for details.)
    Also, for reasons discussed in the Comment Summary and Response 
document available in the docket, we are revising the annual testing 
schedule in the final rule at 40 CFR 63.626(b), and the terminology for 
``maximum representative operating conditions'' in the final rule at 40 
CFR 63.626(d).
    We are not making any changes to the proposed addition of a site-
specific monitoring plan and calibration requirements for CMS. We are 
also keeping the proposed term ``absorber'' in lieu of ``scrubber,'' as 
well as the proposed format of NESHAP subpart BB to reference tables 
for emissions limits and monitoring requirements.
    Lastly, we are retaining the current total fluoride limits and not 
adopting the proposed HF standards and associated EPA Method 320 
testing in NESHAP subpart BB (see section VI.E.3.c of this preamble for 
details).
    ii. NSPS Subpart V. We are not making changes to the proposed 
monitoring and recordkeeping requirements for any granular diammonium 
phosphate plant that commences construction, modification or 
reconstruction after August 19, 2015 to ensure continuous compliance 
with the standard. We are also keeping the proposed term ``absorber'' 
in lieu of ``scrubbing system.''
    iii. NSPS Subpart W. We are not making changes to the proposed 
monitoring and recordkeeping requirements for any TSP plant that 
commences construction, modification or reconstruction after August 19, 
2015 to ensure continuous compliance with the standard. We are also 
keeping the proposed term ``absorber'' in lieu of ``process scrubbing 
system.''
    iv. NSPS Subpart X. We are not making changes to the proposed

[[Page 50428]]

monitoring and recordkeeping requirements for any GTSP storage facility 
that commences construction, modification or reconstruction after 
August 19, 2015 to ensure continuous compliance with the standard. We 
are also keeping the proposed term ``absorber'' in lieu of ``process 
scrubbing system.''
3. What key comments did we receive on the other changes to the 
Phosphate Fertilizer Production NESHAP and NSPS, and what are our 
responses?
    Several comments were received regarding the proposed 
clarifications to applicability and certain definitions, revisions to 
testing, monitoring, recordkeeping and reporting, translation of total 
fluoride to HF emission limits, and revisions to other provisions for 
the Phosphate Fertilizer Production source category. The following is a 
summary of several of these comments and our response to those 
comments. Other comments received and our responses to those comments 
can be found in the Comment Summary and Response document available in 
the docket for this action (EPA-HQ-OAR-2012-0522).
    a. Applicability Clarifications and Certain Definitions--i. 
Phosphate Fertilizer Process Line--Comment. Several commenters 
disapproved of the proposed expansion of the applicability provision 
for DAP and MAP process lines in 40 CFR 63.620(b)(1) to include ``any 
process line that produces a reaction product of ammonia and phosphoric 
acid.'' One commenter asserted that the expanded language could include 
production of non-granular products that were in existence since the 
original NESHAP but not regulated by it, and EPA provided no basis for 
expansion of applicability to bring in these processes now. Other 
commenters also reiterated that the proposed applicability provision 
for DAP and MAP process lines was vague and overbroad and would 
inadvertently regulate any process that combines ammonia and phosphoric 
acid regardless of the end-product or purpose of facility. One 
commenter recommended a change in the definition to clarify that 
subpart BB applies specifically to solid, granulated phosphate products 
to avoid inclusion of liquid fertilizer products in the proposed rule.
    Response. The Agency agrees with the commenter that the proposed 
language could be interpreted to include production of non-granular 
products at a phosphate fertilizer production plant. It was not our 
intent to expand the applicability of 40 CFR subpart BB to include the 
production of non-granular products at a phosphate fertilizer 
production plant; therefore, we are revising the definitions of 
``phosphate fertilizer process line'' and ``phosphate fertilizer 
production plant'' in the final rule at 40 CFR 63.621 to reference 
granular phosphate fertilizer. Also, the definitions of phosphate 
fertilizer process line and phosphate fertilizer production plant were 
defined together at proposal (phosphate fertilizer process line or 
production plant), but are defined separately in the final rule for 
clarity. The definition of phosphate fertilizer process line means 
``any process line that manufactures a granular phosphate fertilizer by 
reacting phosphoric acid with ammonia. A phosphate fertilizer process 
line includes: Reactors, granulators, dryers, coolers, screens, and 
mills.'' The definition of phosphate fertilizer production plant means 
``any production plant that manufactures a granular phosphate 
fertilizer by reacting phosphoric acid with ammonia.''
    As an outgrowth of this comment, the Agency revised rule language 
surrounding the use of ``phosphate fertilizer process line,'' to create 
clarity and consistency in rule language. Specifically, where the 
phrase ``diammonium and/or monoammonium phosphate process line and any 
process line that produces a reaction product of ammonia and phosphoric 
acid'' was used at proposal, this phrase now reads ``phosphate 
fertilizer process line (e.g., diammonium and/or monoammonium phosphate 
process line)'' in the finalized rule. This phrasing was incorporated 
into final rule language at 40 CFR 63.620(b)(1), 63.622(a), 
63.622(a)(1), 63.622(a)(2), 63.625(a), 63.626(f), in Table 1, and in 
Table 2.
    ii. ``Includes, but is Not Limited to''--Comment. A commenter 
remarked that incorporating the language ``includes, but is not limited 
to'' in the definition of DAP and/or MAP process line is overly broad 
and creates ambiguity. They stated that industry should have certainty 
as to the applicability and scope of the rule, but the language 
``includes, but is not limited to'' creates uncertainty as to where the 
affected equipment begins and ends for purposes of demonstrating 
compliance.
    Response. We agree that this language creates overly broad process 
line definitions and can lead to regulatory uncertainty for affected 
sources. Therefore, we are not finalizing the language ``includes, but 
is not limited to'' in the definition of DAP and/or MAP process line.
    b. Testing, Monitoring, Recordkeeping and Reporting--i. Pressure 
Drop Across Absorber--Comment. Several commenters requested the EPA 
delete the requirement that pressure drop across an absorber must be 
greater than 5 inches of water in order to use the option of measuring 
pressure drop as an operating parameter. These commenters contended 
that the EPA has not articulated any basis for the requirement. These 
commenters provided data demonstrating that units operate in compliance 
with the emission standards when the pressure drop across an absorber 
is less than 5 inches of water. One of these commenters expressed 
safety concerns associated with operating scrubbers at higher range 
pressure drop settings, citing that one of its facilities has 
experienced the entrainment of moisture within the absorbing tower when 
operating at pressure drops in excess of 8 inches of water, and another 
has experienced the buildup of excessive fumes on the digester floor 
when operating the digester scrubber as high as 6 inches of water.
    Response. The Agency maintains its determination that pressure drop 
is not an appropriate monitoring parameter for absorbers that do not 
use the energy from the inlet gas to increase contact between the gas 
and liquid in the absorber (see ``Use of Pressure Drop as an Operating 
Parameter,'' which is available in Docket ID No. EPA-HQ-OAR-2012-0522). 
Therefore, we are not revising this proposed amendment. For further 
explanation please see our response to the identical comment that was 
made for NESHAP subpart AA in section V.F.3.b.i of this preamble.
    ii. Absorber Monitoring Options--Comment. Several commenters called 
attention to the options of either measuring: (1) The temperature at 
the wet scrubber gas stream outlet and pressure at the liquid inlet of 
the absorber, or (2) the temperature at the scrubber gas stream outlet 
and scrubber gas stream inlet. One of these commenters said that they 
do not believe monitoring gas temperature in locations of large ambient 
temperature ranges would provide accurate monitoring of the absorbers 
performance. The commenter argued that temperature and pressure probes 
would be very susceptible to scaling issues. In addition, this 
commenter contended that liquid inlet pressure does not provide any 
additional monitoring of the absorber performance, since the inlet 
liquid flow rate is already measured and monitored. Another commenter 
contended that the EPA has not provided any data or analysis to show 
that there is a correlation between temperature and emissions; the 
commenter stated that they were not

[[Page 50429]]

aware of any data suggesting a relationship between exit temperature 
and emissions, or that monitoring temperature difference across an 
absorber would be effective. One of these commenters argued that they 
were not in a position to evaluate the difficulties associated with 
performing the associated monitoring and establishing the requisite 
operating ranges.
    Response. Absorber outlet gas temperature is often used to indicate 
a change in operation for absorbers used to control thermal processes. 
Because this source category does not use a thermal process to produce 
fertilizer, the Agency agrees with the commenters that temperature is 
not an appropriate monitoring parameter for absorbers used in this 
source category, and has removed these monitoring options from Table 3 
of the final rule (NESHAP subpart BB). However, in light of this 
comment, the Agency has revised Table 3 of NESHAP subpart BB to require 
liquid-to-gas ratio monitoring for low-energy absorbers (i.e., 
absorbers that are designed to operate with pressure drops of 5 inches 
of water column or less) in lieu of monitoring influent liquid flow and 
pressure drop through the absorber. Furthermore, the Agency has revised 
Table 3 of NESHAP subpart BB to require influent liquid flow and 
pressure drop monitoring for high-energy (i.e., high pressure drop) 
absorbers, such as venturi scrubbers; and we are keeping liquid-to-gas 
ratio monitoring as an option for high-energy absorbers in the final 
rule. For further explanation please see our response to the identical 
comment that was made for NESHAP subpart AA in section V.F.3.b.ii of 
this preamble.
    iii. Acceptable Range From Baseline Average Value--Comment. One 
commenter requested that the EPA revise 40 CFR 63.625(d)(1)(ii)(B) to 
have similar wording to 40 CFR 63.625(d)(1)(ii)(A), in which the 
allowable parametric limits may encompass up to +/-20 percent of the of 
the baseline average values for the series of tests used under this 
option; that is, the parametric limit may extend -20 percent below the 
lowest baseline average and up to +20 percent above the highest 
baseline average from the series of performance tests used for this 
option.
    Response. The Agency determined that it is not necessary to revise 
40 CFR 63.625(d)(1)(ii)(B) to allow for a 20 percent 
operating margin, as this commenter requests, because this provision 
already allows owners or operators to establish an operating limit 
range for a control device without having to apply an operating margin, 
such as 20 percent. Owners or operators that use an 
absorber or a WESP to comply with the emission limits (and monitor 
pressure drop across each absorber or secondary voltage for a WESP) 
have two options to establish operating limits for demonstrating 
continuous compliance: (1) At 40 CFR 63.625(d)(1)(ii)(A), the operating 
limits may be determined using the most recent performance test and 
applying an operating margin of 20 percent (e.g., during 
the three test runs conducted for an owner's or operator's most recent 
performance test that demonstrated compliance with the emission limit, 
the arithmetic average of the absorber pressure drops recorded was 7 
inches of water; therefore, under this option, the owner's or 
operator's operating limit range for this absorber would be 5.6 to 8.4 
inches of water, or 20 percent of 7); or (2) at 40 CFR 
63.625(d)(1)(ii)(B), owners or operators may establish operating limit 
ranges based upon baseline values of operating parameters established 
in either historic performance tests or performance tests conducted 
specifically to establish such ranges (e.g., an owner or operator could 
choose to conduct two consecutive performance tests consisting of three 
test runs each and if the owner or operator demonstrates compliance 
with the emission limit while operating an absorber with a pressure 
drop of 6 inches of water during the first performance test, and then 
in the second performance test the owner or operator demonstrates 
compliance with the emission limit while operating an absorber with a 
pressure drop of 10 inches of water, the owner's or operator's 
operating limit range for this absorber would be 6 to 10 inches of 
water under this option). Additionally, the rule permits owners or 
operators to undertake additional performance testing (for either 
option) to establish control device operating limits which reflect 
compliance with the emission limit for the full range of operating 
conditions of the control device. Therefore, the Agency has determined 
that no change to 40 CFR 63.625(d)(1)(ii)(B) is warranted.
    iv. Operating Range Established From a Previous Test--Comment. One 
commenter stated that 40 CFR 63.627(a) is somewhat ambiguous, tending 
to suggest that affected facilities would be immediately required to 
implement new equipment operating ranges following a source test, even 
if operating conditions from previous source tests demonstrated 
compliance with fluoride emission standards. The commenter argued that 
there is no reason that a new performance test at a new operating range 
should invalidate a previous performance test at a different operating 
range.
    Response. The Agency has clarified in the final rule at 40 CFR 
63.627(a) that during the most recent performance test, if owners or 
operators demonstrate compliance with the emission limit while 
operating their control device outside the previously established 
operating limit, then limits must be established. Owners or operators 
must establish a new operating limit based on that most recent 
performance test and notify the Administrator that the operating limit 
changed based on data collected during the most recent performance 
test. For further explanation please see our response to the identical 
comment that was made for NESHAP subpart AA in section V.F.3.b.iii of 
this preamble.
    v. Approving Operating Ranges--Comment. Several commenters support 
the EPA's proposal to eliminate the requirement that facilities may not 
implement new operating parameter ranges until the Administrator has 
approved them, or 30 days have passed since submission of the 
performance test results. However, two of these commenters pointed out 
that the EPA did not make the same allowance in 40 CFR 
63.625(d)(1)(ii)(B), where a series of tests (potentially including 
historical tests) are used to establish an operating range. A commenter 
pointed out that 40 CFR 63.625(d)(1)(ii)(B), as proposed, does not 
provide the 30-day default period for the effectiveness of the new 
ranges if the EPA Administrator does not act; therefore, as currently 
set forth in the proposed rule, sources will be left in limbo waiting 
for the EPA Administrator to respond before they can implement new 
ranges. A commenter suggested that the EPA revise the proposed 
regulatory language to require submission of the new ranges to EPA, but 
delete the requirement to request and obtain EPA's approval of the new 
ranges. Similarly, another commenter requested the EPA clarify the 
process for establishing new equipment operating ranges following 
source performance testing. This commenter contended that facilities 
should have the ability to update operating parameters if they desire 
based on source testing, and the facility should be required to submit 
the new ranges, but not be required to obtain EPA's approval of the new 
ranges.
    In addition, a commenter requested that the EPA clarify how 
revising the proposed regulatory language to require submission of the 
new ranges to the

[[Page 50430]]

EPA, but deleting the requirement to request and obtain EPA's approval 
of the new ranges, will affect possible obligations to undertake permit 
modifications of title V permits under 40 CFR part 70. This commenter 
stated that such administrative processes are not fully anticipated in 
the proposed rule.
    Response. In the proposed NESHAP subpart BB, the Agency intended 
that facilities not be required to obtain approval, and instead, 
immediately comply with a new operating limit when it is developed and 
submitted to the Administrator. Therefore, the requirements at 40 CFR 
63.625(d)(1)(ii)(B) have been revised in the final rule, as the 
commenter requests, to remove the requirement that facilities must 
request and obtain approval of the Administrator for changing operating 
limits. Furthermore, the Agency suggests that the title V permit be 
modified as soon as the Administrator is notified of a change in an 
operating limit. The Agency acknowledges that corrections and 
modifications to permit applications could become a problem for a 
facility, particularly if the Administrator determines the operating 
limit is not appropriate after a facility has already applied for the 
change to be made in their air permit; however, we expect this scenario 
to be rare.
    c. Translation of Total Fluoride to HF Emission Limits--Comment. 
Several commenters expressed concerns regarding the methodology for 
expressing the existing total fluoride limits in terms of HF (refer to 
section V.F.3.c of this preamble for a summary of comments received on 
this topic).
    Response. In light of information provided by commenters, the 
Agency has re-evaluated the proposed revision to the standard and 
determined that EPA Method 320 is not an appropriate test method for 
accurately measuring HF emissions from process lines at this specific 
source category due to the complex and often incomplete chemical 
reactions with silicon compounds in these sources. Accordingly, we are 
not adopting the proposed HF standards, and instead we are retaining 
the existing total fluoride limits for all emission sources in subpart 
BB. For further explanation on this determination, refer to section 
V.F.3.c of this preamble. Although, at the present time, the Agency is 
not finalizing HF standards in NESHAP subpart BB, it may be possible to 
do so in a future rulemaking with additional data and specificity on 
monitoring requirements.
4. What is the rationale for our final decisions regarding these other 
changes to the Phosphate Fertilizer Production NESHAP and NSPS?
    For the reasons provided above and in the preamble for the proposed 
rule, we are finalizing the proposed requirement in NESHAP subpart BB 
that pressure drop across an absorber must be greater than 5 inches of 
water in order to use the option of measuring pressure drop as an 
operating parameter; and other proposed clarifications and corrections.
    Additionally, for the reasons provided above, we are making the 
revisions, clarifications and corrections noted in section VI.E.2 in 
the final rules for NESHAP subpart BB, NSPS subpart V, NSPS subpart W, 
and NSPS subpart X.

VII. Summary of Cost, Environmental, and Economic Impacts and 
Additional Analyses Conducted

A. What are the affected facilities?

    We anticipate that the 13 facilities currently operating in the 
U.S. will be affected by these amendments. We do not expect any new 
facilities to be constructed or expanded in the foreseeable future.

B. What are the air quality impacts?

    We anticipate HF emissions reductions as a result of one facility 
installing controls on its oxidation reactor to comply with the SPA 
total fluoride limit. However, we do not have emissions data for its 
oxidation reactor to calculate these reductions. In addition, the 
revised rule will mitigate future increases of Hg emissions from 
phosphate rock calciners by requiring compliance with numeric emission 
limits.

C. What are the cost impacts?

    We have estimated compliance costs for all existing sources to add 
the necessary controls and monitoring devices, perform inspections, and 
implement recordkeeping and reporting requirements to comply with the 
final rules. Based on this analysis, we anticipate an overall total 
capital investment of $346,000, with an associated total annualized 
cost of approximately $294,000. We do not anticipate the construction 
of any new phosphoric acid manufacturing plants or phosphate fertilizer 
production facilities in the next 5 years. Therefore, there are no 
anticipated new source cost impacts. We estimated the cost to install a 
venturi scrubber to meet the SPA process line total fluoride standard, 
when oxidation reactor emissions are included, for one facility. For 
all emission sources, we calculated capital and annual costs for 
testing, monitoring, recordkeeping, and reporting. The memorandum, 
``Control Costs and Emissions Reductions for Phosphoric Acid and 
Phosphate Fertilizer Production Source Categories--Final Rule,'' which 
is available in the docket for this action, documents the control cost 
analyses.

D. What are the economic impacts?

    Economic impact analyses focus on changes in market prices and 
output levels. If changes in market prices and output levels in the 
primary markets are significant, we also examine impacts on other 
markets. Both the magnitude of costs needed to comply with the rule and 
the distribution of these costs among affected facilities can have a 
role in determining how the market will change in response to the rule. 
We project that no facility will incur significant costs.
    Because no small firms will incur control costs, there is no 
significant impact on small entities. Thus, we do not expect this 
regulation to have a significant impact on a substantial number of 
small entities.

E. What are the benefits?

    The revised rule will mitigate future increases of Hg emissions 
from phosphate rock calciners by requiring compliance with numeric 
emission limits. These avoided emissions will result in improvements in 
air quality and reduced negative health effects associated with 
exposure to air pollution of these emissions. However, we have not 
quantified or monetized the benefits of reducing these emissions for 
this rulemaking because information is not available to monetize 
potential benefits and we are not aware of any new phosphate rock 
calciners that will be constructed in the next three years.

F. What analysis of environmental justice did we conduct?

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practical and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies and activities on minority populations and low-income 
populations in the U.S.
    The EPA has determined that this rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority, low-

[[Page 50431]]

income, or indigenous populations because it increases the level of 
environmental protection for all affected populations without having 
any disproportionately high and adverse human health or environmental 
effects on any population, including any minority or low-income 
population. To gain a better understanding of the source category and 
near source populations, the EPA conducted a proximity analysis on 
phosphate facilities to identify any overrepresentation of minority, 
low income, or indigenous populations. This analysis only gives some 
indication of the prevalence of sub-populations that may be exposed to 
air pollution from the sources; it does not identify the demographic 
characteristics of the most highly affected individuals or communities, 
nor does it quantify the level of risk faced by those individuals or 
communities.
    The proximity analysis reveals that most demographic categories are 
below or within 20 percent of their corresponding national averages. 
The two exceptions are the minority and African American populations. 
The ratio of African Americans living within 3 miles of any source 
affected by this rule is 131 percent higher than the national average 
(29 percent versus 13 percent). The percentage of minorities living 
within 3 miles of any source affected by this rule is 37 percent above 
the national average (35 percent versus 28 percent). The large minority 
population is a direct result of the higher percentage of African 
Americans living near these facilities (the other racial minorities are 
below or equal to the national average). However, as noted previously, 
we found the risks from these source categories to be acceptable for 
all populations.
    The changes to the standard increase the level of environmental 
protection for all affected populations by ensuring no future emission 
increases from the source categories. The proximity analysis results 
and the details concerning their development are presented in the 
October 2012 memorandum, ``Environmental Justice Review: Phosphate 
Fertilizer Production and Phosphoric Acid,'' a copy of which is 
available in Docket ID No. EPA-HQ-OAR-2012-0522.

G. What analysis of children's environmental health did we conduct?

    While this action is not subject to Executive Order 13045 (62 FR 
19885, April 23, 1997), we note that the current standards provide an 
ample margin of safety to protect public health. Consideration of 
children's health is accounted for in our risk analyses, which compare 
projected exposures to various health benchmarks that are based on the 
most sensitive populations.

VIII. Statutory and Executive Order Reviews

A. Executive Orders 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was, 
therefore, not submitted to the Office of Management and Budget (OMB) 
for review. The EPA analyzed the potential costs and benefits 
associated with this action. The results are presented in sections 
VII.C and E of this preamble.

B. Paperwork Reduction Act (PRA)

    The information collection activities in these rules have been 
submitted for approval to OMB under the PRA. The Information Collection 
Request (ICR) document that the EPA prepared has been assigned EPA ICR 
number 1790.06. You can find a copy of the ICR in the docket for this 
rule, and it is briefly summarized here. The information collection 
requirements are not enforceable until OMB approves them.
    We are finalizing new paperwork requirements to the Phosphoric Acid 
Manufacturing and Phosphate Fertilizer Production source categories in 
the form of additional requirements for stack testing, performance 
evaluations, and work practices for fugitive sources.
    We estimate 12 regulated entities are currently subject to 40 CFR 
part 63, subpart AA and 11 regulated entities are currently subject to 
40 CFR part 63, subpart BB and each will be subject to all applicable 
standards. The annual monitoring, reporting, and recordkeeping burden 
for these amendments to subpart AA and BB is estimated to be $224,000 
per year (averaged over the first 3 years after the effective date of 
the standards). This includes 670 labor hours per year at a total labor 
cost of $55,000 per year, and total non-labor capital and operating and 
maintenance costs of $169,000 per year. This estimate includes 
performance tests, notifications, reporting and recordkeeping 
associated with the new requirements for emission points and associated 
control devices. The total burden to the federal government is 
estimated to be 330 hours per year at a total labor cost of $17,000 per 
year (averaged over the first 3 years after the effective date of the 
standard). Burden is defined at 5 CFR 1320.3(b).
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities contained in this final rule.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, the impact of concern is any significant 
adverse economic impact on small entities. An agency may certify that a 
rule will not have a significant economic impact on a substantial 
number of small entities if the rule relieves regulatory burden, has no 
net burden or otherwise has a positive economic effect on the small 
entities subject to the rule. This rule will not impose any 
requirements on small entities because we do not project that any small 
entities will incur costs due to these rule amendments. We have 
therefore concluded that this action will have no net regulatory burden 
for all directly regulated small entities.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The action imposes no enforceable duty on any state, 
local, or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

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

    This action has tribal implications. However, it will neither 
impose substantial direct compliance costs on federally recognized 
tribal governments, nor preempt tribal law. The tribal implications are 
primarily due to the close proximity of one facility to a tribe (the 
Shoshone-Bannock).
    The EPA consulted with tribal officials under the EPA Policy on

[[Page 50432]]

Consultation and Coordination with Indian Tribes early in the process 
of developing this regulation to permit them to have meaningful and 
timely input into its development. The Agency provided an overview of 
the source categories and rulemaking process during a monthly 
teleconference with the National Tribal Air Association. Additionally, 
we provided targeted outreach, including a visit to the Shoshone-
Bannock tribe and meeting with environmental leaders for the tribe.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action's health and risk assessments are contained in 
sections V.A. and VI.A.

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

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
part 51

    This action involves technical standards. The EPA has decided to 
use analytical methods of the Association of Official Analytical 
Chemists (AOAC) and of the Association of Fertilizer and Phosphate 
Chemists (AFPC). The AOAC methods include: AOAC Official Method 957.02 
Phosphorus (Total) in Fertilizers, Preparation of Sample Solution, AOAC 
Official Method 929.01 Sampling of Solid Fertilizers, AOAC Official 
Method 929.02 Preparation of Fertilizer Sample, AOAC Official Method 
978.01 Phosphorous (Total) in Fertilizers, Automated Method, AOAC 
Official Method 969.02 Phosphorous (Total) in Fertilizers, Alkalimetric 
Quinolinium Molybdophosphate Method, AOAC Official Method 962.02 
Phosphorous (Total) in Fertilizers, Gravimetric Quinolinium 
Molybdophosphate Method and Quinolinium Molybdophosphate Method 958.01 
Phosphorous (Total) in Fertilizers, Spectrophotometric 
Molybdovanadophosphate Method. The AFPC methods for analysis of 
phosphate rock include: No. 1 Preparation of Sample, No. 3 Phosphorus-
P2O5 or 
Ca3(PO4)2, Method A--Volumetric 
Method, No. 3 Phosphorus-P2O5 or 
Ca3(PO4)2, Method B--Gravimetric 
Quimociac Method, No. 3 Phosphorus-P2O5 or 
Ca3(PO4)2, Method C--
Spectrophotometric Method. The AFPC methods for analysis of phosphoric 
acid, superphosphate, triple superphosphate and ammonium phosphates 
include: No. 3 Total Phosphorus-P2O5, Method A-
Volumetric Method, No. 3 Total Phosphorus-P2O5, 
Method B--Gravimetric Quimociac Method and No. 3 Total Phosphorus-
P2O5, Method C--Spectrophotometric Method.
    As discussed in the preamble of the proposal, under NESHAP subpart 
AA and NESHAP subpart BB, we conducted searches for EPA Methods 5, 13A, 
13B, and 30B. The EPA conducted searches through the Enhanced National 
Standards Systems Network (NSSN) Database managed by the American 
National Standards Institute (ANSI). We contacted voluntary consensus 
standards (VCS) organizations, and accessed and searched their 
databases. We did not identify any applicable VCS for EPA Methods 5, 
13A, 13B, or 30B. Additional information for the VCS search and 
determinations can be found in the memorandum, ``Voluntary Consensus 
Standard Results for Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production RTR and Standards of Performance for Phosphate 
Processing,'' which is available in the docket for this action. The EPA 
solicited comments on VCS and invited the public to identify 
potentially applicable VCS; however, we did not receive comments 
regarding this aspect of NESHAP subpart AA and NESHAP subpart BB.
    The EPA is incorporating, into NESHAP subpart AA and NESHAP subpart 
BB, the following guidance document: EPA-454/R-98-015, Office Of Air 
Quality Planning And Standards (OAQPS), Fabric Filter Bag Leak 
Detection Guidance, September 1997. This guidance document provides 
procedures for selecting, installing, setting up, adjusting, and 
operating a bag leak detection system; and also includes quality 
assurance procedures. This guidance document is readily accessible at 
http://www.epa.gov/ttn/emc/cem.html.

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

    The EPA believes the human health or environmental risk addressed 
by this action will not have potential disproportionately high and 
adverse human health or environmental effects on minority, low-income, 
or indigenous populations because it increases the level of protection 
provided to human health or the environment. The results of this 
evaluation are contained in the memorandum titled ``Environmental 
Justice Review: Phosphate Fertilizer Production and Phosphoric Acid,'' 
which is available in Docket ID No. EPA-HQ-OAR-2012-0522, and are 
discussed in section VII.F of this preamble.

K. Congressional Review Act

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the U.S. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).

List of Subjects

40 CFR Part 60

    Environmental protection, Air pollution control, Fertilizers, 
Fluoride, Particulate matter, Phosphate, Reporting and recordkeeping 
requirements.

40 CFR Part 63

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Hazardous substances, Incorporation by 
reference, Intergovernmental relations, Reporting and recordkeeping 
requirements.

    Dated: July 21, 2015.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, parts 60 and 63 of title 
40, chapter I, of the Code of Federal Regulations are amended as 
follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

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

Subpart T--Standards of Performance for the Phosphate Fertilizer 
Industry: Wet-Process Phosphoric Acid Plants

0
2. Section 60.200 is amended by revising paragraph (a) to read as 
follows:

Sec.  60.200  Applicability and designation of affected facility.

    (a) The affected facility to which the provisions of this subpart 
apply is each wet-process phosphoric acid plant having a design 
capacity of more than 15 tons of equivalent P2O5 
feed per calendar day.
* * * * *

[[Page 50433]]

0
3. Section 60.201 is amended by revising paragraph (a) to read as 
follows:

Sec.  60.201  Definitions.

* * * * *
    (a) Wet-process phosphoric acid plant means any facility 
manufacturing phosphoric acid by reacting phosphate rock and acid. A 
wet-process phosphoric acid plant includes: Reactors, filters, 
evaporators, and hot wells.
* * * * *

0
4. Section 60.203 is amended by revising paragraph (c) and adding 
paragraph (d) to read as follows:

Sec.  60.203  Monitoring of operations.

* * * * *
    (c) The owner or operator of any wet-process phosphoric acid plant 
subject to the provisions of this part shall install, calibrate, 
maintain, and operate a monitoring device which continuously measures 
and permanently records the total pressure drop across the absorber. 
The monitoring device shall have an accuracy of 5 percent 
over its operating range.
    (d) Any facility under Sec.  60.200(a) that commences construction, 
modification or reconstruction after November 7, 2014 is subject to the 
requirements of this paragraph instead of the requirements in paragraph 
(c) of this section. If an absorber is used to comply with Sec.  
60.202, then the owner or operator shall continuously monitor pressure 
drop through the absorber and meet the requirements specified in 
paragraphs (d)(1) through (4) of this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.

0
5. Subpart T is amended by adding Sec.  60.205 to read as follows:

Sec.  60.205  Recordkeeping.

    Any facility under Sec.  60.200(a) that commences construction, 
modification or reconstruction after November 7, 2014 is subject to the 
requirements of this section. You must maintain the records identified 
as specified in Sec.  60.7(f) and in paragraphs (a) and (b) of this 
section. All records required by this subpart must be maintained on 
site for at least 5 years.
    (a) Records of the daily average pressure. Records of the daily 
average pressure drop through the absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.203(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart U--Standards of Performance for the Phosphate Fertilizer 
Industry: Superphosphoric Acid Plants

0
6. Section 60.210 is amended by revising paragraph (a) to read as 
follows:

Sec.  60.210  Applicability and designation of affected facility.

    (a) The affected facility to which the provisions of this subpart 
apply is each superphosphoric acid plant having a design capacity of 
more than 15 tons of equivalent P2O5 feed per 
calendar day.
* * * * *

0
7. Section 60.211 is amended by revising paragraph (a) to read as 
follows:

Sec.  60.211  Definitions.

* * * * *
    (a) Superphosphoric acid plant means any facility that concentrates 
wet-process phosphoric acid to 66 percent or greater 
P2O5 content by weight for eventual consumption 
as a fertilizer. A superphosphoric acid plant includes: evaporators, 
hot wells, acid sumps, oxidation reactors, and cooling tanks. An 
oxidation reactor includes any equipment or step that uses an oxidizing 
agent (e.g., nitric acid, ammonium nitrate, or potassium permanganate) 
to treat superphosphoric acid.
* * * * *

0
8. Section 60.213 is amended by revising paragraph (c) and adding 
paragraph (d) to read as follows:

Sec.  60.213  Monitoring of operations.

* * * * *
    (c) Except as specified in paragraph (d) of this section, the owner 
or operator of any superphosphoric acid plant subject to the provisions 
of this part shall install, calibrate, maintain, and operate a 
monitoring device which continuously measures and permanently records 
the total pressure drop across the absorber. The monitoring device 
shall have an accuracy of 5 percent over its operating 
range.
    (d) Any affected facility as defined in Sec.  60.210(a) that 
commences construction, modification or reconstruction after November 
7, 2014 is subject to the requirements of this paragraph instead of the 
requirements in paragraph (c) of this section. If an absorber is used 
to comply with Sec.  60.212, then the owner or operator shall 
continuously monitor pressure drop through the absorber and meet the 
requirements specified in paragraphs (d)(1) through (4) of this 
section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.

[[Page 50434]]

    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.

0
9. Subpart U is amended by adding Sec.  60.215 to read as follows:

Sec.  60.215  Recordkeeping.

    An affected facility as defined in Sec.  60.210(a) that commences 
construction, modification, or reconstruction after November 7, 2014 is 
subject to the requirements of this section. You must maintain the 
records identified as specified in Sec.  60.7(f) and in paragraphs (a) 
and (b) of this section. All records required by this subpart must be 
maintained on site for at least 5 years.
    (a) Records of the daily average pressure. Records of the daily 
average pressure drop through the absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.213(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart V--Standards of Performance for the Phosphate Fertilizer 
Industry: Diammonium Phosphate Plants

0
10. Section 60.223 is amended by revising paragraph (c) and adding 
paragraph (d) to read as follows:

Sec.  60.223  Monitoring of operations.

* * * * *
    (c) Except as specified in paragraph (d) of this section, the owner 
or operator of any granular diammonium phosphate plant subject to the 
provisions of this subpart shall install, calibrate, maintain, and 
operate a monitoring device which continuously measures and permanently 
records the total pressure drop across the scrubbing system. The 
monitoring device shall have an accuracy of 5 percent over 
its operating range.
    (d) Any affected facility as defined in Sec.  60.220(a) that 
commences construction, modification, or reconstruction after November 
7, 2014 is subject to the requirements of this paragraph instead of the 
requirements in paragraph (c) of this section. If an absorber is used 
to comply with Sec.  60.222, then the owner or operator shall 
continuously monitor pressure drop through the absorber and meet the 
requirements specified in paragraphs (d)(1) through (4) of this 
section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.

0
11. Section 60.224 is amended by revising paragraph (b)(3)(ii) to read 
as follows:

Sec.  60.224  Test methods and procedures.

* * * * *
    (b) * * *
    (3) * * *
    (ii) The Association of Official Analytical Chemists (AOAC) Method 
9 (incorporated by reference--see Sec.  60.17) shall be used to 
determine the P2O5 content (Rp) of the 
feed.

0
12. Subpart V is amended by adding Sec.  60.225 to read as follows:

Sec.  60.225  Recordkeeping.

    An affected facility as defined in Sec.  60.220(a) that commences 
construction, modification, or reconstruction after November 7, 2014 is 
subject to the requirements of this section. You must maintain the 
records identified as specified in Sec.  60.7(f) and in paragraphs (a) 
and (b) of this section. All records required by this subpart must be 
maintained on site for at least 5 years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.223(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

[[Page 50435]]

Subpart W--Standards of Performance for the Phosphate Fertilizer 
Industry: Triple Superphosphate Plants

0
13. Section 60.230 is amended by revising paragraph (a) to read as 
follows:

Sec.  60.230  Applicability and designation of affected facility.

    (a) The affected facility to which the provisions of this subpart 
apply is each triple superphosphate plant having a design capacity of 
more than 15 tons of equivalent P2O5 feed per 
calendar day. For the purpose of this subpart, the affected facility 
includes any combination of: mixers, curing belts (dens), reactors, 
granulators, dryers, coolers, screens, mills, and facilities that store 
run-of-pile triple superphosphate.
* * * * *

0
14. Section 60.233 is revised to read as follows:

Sec.  60.233  Monitoring of operations.

    (a) The owner or operator of any triple superphosphate plant 
subject to the provisions of this subpart shall install, calibrate, 
maintain, and operate a flow monitoring device that can be used to 
determine the mass flow of phosphorus-bearing feed material to the 
process. The flow monitoring device shall have an accuracy of 5 percent over its operating range.
    (b) The owner or operator of any triple superphosphate plant shall 
maintain a daily record of equivalent P2O5 feed 
by first determining the total mass rate in Mg/hr of phosphorus-bearing 
feed using a flow monitoring device meeting the requirements of 
paragraph (a) of this section and then by proceeding according to Sec.  
60.234(b)(3).
    (c) Except as specified in paragraph (d) of this section, the owner 
or operator of any triple superphosphate plant subject to the 
provisions of this part shall install, calibrate, maintain, and operate 
a monitoring device that continuously measures and permanently records 
the total pressure drop across the absorber. The monitoring device 
shall have an accuracy of 5 percent over its operating 
range.
    (d) Any facility under Sec.  60.230(a) that commences construction, 
modification, or reconstruction after November 7, 2014 is subject to 
the requirements of this paragraph instead of the requirements in 
paragraph (c) of this section. If an absorber is used to comply with 
Sec.  60.232, then the owner or operator shall continuously monitor 
pressure drop through the absorber and meet the requirements specified 
in paragraphs (d)(1) through (4) of this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.

0
15. Subpart W is amended by adding Sec.  60.235 to read as follows:

Sec.  60.235  Recordkeeping.

    Any facility under Sec.  60.230(a) that commences construction, 
modification, or reconstruction after November 7, 2014 is subject to 
the requirements of this section. You must maintain the records 
identified as specified in Sec.  60.7(f) and in paragraphs (a) and (b) 
of this section. All records required by this subpart must be 
maintained onsite for at least 5 years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.233(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart X--Standards of Performance for the Phosphate Fertilizer 
Industry: Granular Triple Superphosphate Storage Facilities

0
16. Section 60.243 is amended by revising paragraph (c) and adding (e) 
to read as follows:

Sec.  60.243  Monitoring of operations.

* * * * *
    (c) Except as specified in paragraph (e) of this section, the owner 
or operator of any granular triple superphosphate storage facility 
subject to the provisions of this subpart shall install, calibrate, 
maintain, and operate a monitoring device that continuously measures 
and permanently records the total pressure drop across any absorber. 
The monitoring device shall have an accuracy of 5 percent 
over its operating range.
* * * * *
    (e) Any facility under Sec.  60.240(a) that commences construction, 
modification, or reconstruction after November 7, 2014 is subject to 
the requirements of this paragraph instead of the requirements in 
paragraph (c) of this section. If an absorber is used to comply with 
Sec.  60.232, then the owner or operator shall continuously monitor 
pressure drop through the absorber and meet the requirements specified 
in paragraphs (e)(1) through (4) of this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the

[[Page 50436]]

pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (e)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.

0
17. Subpart X is amended by adding Sec.  60.245 to read as follows:

Sec.  60.245  Recordkeeping.

    Any facility under Sec.  60.240(a) that commences construction, 
modification, or reconstruction after November 7, 2014 is subject to 
the requirements of this section. You must maintain the records 
identified as specified in Sec.  60.7(f) and in paragraphs (a) and (b) 
of this section. All records required by this subpart must be 
maintained onsite for at least 5 years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.243(e)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

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

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

Subpart A--General Provisions

0
19. Section 63.14 is amended by revising paragraphs (b), (c)(1) through 
(7), and (l)(2) to read as follows:

Sec.  63.14  Incorporations by reference.

* * * * *
    (b) The Association of Florida Phosphate Chemists, P.O. Box 1645, 
Bartow, Florida 33830.
    (1) Book of Methods Used and Adopted By The Association of Florida 
Phosphate Chemists, Seventh Edition 1991:
    (i) Section IX, Methods of Analysis for Phosphate Rock, No. 1 
Preparation of Sample, IBR approved for Sec.  63.606(f), Sec.  
63.626(f).
    (ii) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or Ca3(PO4)2, Method A--Volumetric Method, IBR approved 
for Sec.  63.606(f), Sec.  63.626(f).
    (iii) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or Ca3(PO4)2, Method B--Gravimetric Quimociac Method, 
IBR approved for Sec.  63.606(f), Sec.  63.626(f).
    (iv) Section IX, Methods of Analysis For Phosphate Rock, No. 3 
Phosphorus-P2O5 or Ca3(PO4)2, Method C--Spectrophotometric Method, IBR 
approved for Sec.  63.606(f), Sec.  63.626(f).
    (v) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A--Volumetric Method, IBR approved for 
Sec.  63.606(f), Sec.  63.626(f), and (g).
    (vi) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B--Gravimetric Quimociac Method, IBR 
approved for Sec.  63.606(f), Sec.  63.626(f), and (g).
    (vii) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method C--Spectrophotometric Method, IBR 
approved for Sec.  63.606(f), Sec.  63.626(f), and (g).
    (2) [Reserved]
    (c) * * *
    (1) AOAC Official Method 929.01 Sampling of Solid Fertilizers, 
Sixteenth edition, 1995, IBR approved for Sec.  63.626(g).
    (2) AOAC Official Method 929.02 Preparation of Fertilizer Sample, 
Sixteenth edition, 1995, IBR approved for Sec.  63.626(g).
    (3) AOAC Official Method 957.02 Phosphorus (Total) in Fertilizers, 
Preparation of Sample Solution, Sixteenth edition, 1995, IBR approved 
for Sec.  63.626(g).
    (4) AOAC Official Method 958.01 Phosphorus (Total) in Fertilizers, 
Spectrophotometric Molybdovanadophosphate Method, Sixteenth edition, 
1995, IBR approved for Sec.  63.626(g).
    (5) AOAC Official Method 962.02 Phosphorus (Total) in Fertilizers, 
Gravimetric Quinolinium Molybdophosphate Method, Sixteenth edition, 
1995, IBR approved for Sec.  63.626(g).
    (6) AOAC Official Method 969.02 Phosphorus (Total) in Fertilizers, 
Alkalimetric Quinolinium Molybdophosphate Method, Sixteenth edition, 
1995, IBR approved for Sec.  63.626(g).
    (7) AOAC Official Method 978.01 Phosphorus (Total) in Fertilizers, 
Automated Method, Sixteenth edition, 1995, IBR approved for Sec.  
63.626(g).
* * * * *
    (l) * * *
    (2) EPA-454/R-98-015, Office Of Air Quality Planning And Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance, September 1997, IBR 
approved for Sec. Sec.  63.548(e), 63.606(m), 63.607(b), 63.626(h), 
63.627(b), 63.7525(j), and 63.11224(f).
* * * * *

0
20. Part 63 is amended by revising subpart AA to read as follows:

Subpart AA--National Emission Standards for Hazardous Air 
Pollutants from Phosphoric Acid Manufacturing Plants

Sec.
63.600 Applicability.
63.601 Definitions.
63.602 Standards and compliance dates.
63.603 [Reserved]
63.604 [Reserved]
63.605 Operating and monitoring requirements.
63.606 Performance tests and compliance provisions.
63.607 Notification, recordkeeping, and reporting requirements.
63.608 General requirements and applicability of general provisions 
of this part.
63.609 [Reserved]
63.610 Exemption from new source performance standards.
63.611 Implementation and enforcement.

[[Page 50437]]

Table 1 to Subpart AA of Part 63--Existing Source Emission Limits
Table 2 to Subpart AA of Part 63--New Source Emission Limits
Table 3 to Subpart AA of Part 63--Monitoring Equipment Operating 
Parameters
Table 4 to Subpart AA of Part 63--Operating Parameters, Operating 
Limits and Data Monitoring, Recordkeeping and Compliance Frequencies
Table 5 to Subpart AA of Part 63--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring System (CPMS)
Appendix A to Subpart AA of Part 63--Applicability of General 
Provisions (40 CFR part 63, subpart A) to Subpart AA

Sec.  63.600  Applicability.

    (a) Except as provided in paragraphs (c) and (d) of this section, 
you are subject to the requirements of this subpart if you own or 
operate a phosphoric acid manufacturing plant that is a major source as 
defined in Sec.  63.2. You must comply with the emission limitations, 
work practice standards, and operating parameter requirements specified 
in this subpart at all times.
    (b) The requirements of this subpart apply to emissions of 
hazardous air pollutants (HAP) emitted from the following affected 
sources at a phosphoric acid manufacturing plant:
    (1) Each wet-process phosphoric acid process line.
    (2) Each evaporative cooling tower.
    (3) Each phosphate rock dryer.
    (4) Each phosphate rock calciner.
    (5) Each superphosphoric acid process line.
    (6) Each purified phosphoric acid process line.
    (7) Each gypsum dewatering stack.
    (8) Each cooling pond.
    (c) The requirements of this subpart do not apply to a phosphoric 
acid manufacturing plant that is an area source as defined in Sec.  
63.2.
    (d) The provisions of this subpart do not apply to research and 
development facilities as defined in Sec.  63.601.

Sec.  63.601  Definitions.

    Terms used in this subpart are defined in Sec.  63.2 of the Clean 
Air Act and in this section as follows:
    Active gypsum dewatering stack means a gypsum dewatering stack that 
is currently receiving gypsum, received gypsum within the last year, or 
is part of the facility's water management system. A gypsum dewatering 
stack that is considered closed by a state authority is not considered 
an active gypsum dewatering stack.
    Breakthrough means the point in time when the level of mercury 
detected at the outlet of an adsorber system is 90 percent of the 
highest concentration allowed to be discharged consistent with the 
applicable emission limit.
    Cooling pond means a natural or artificial open reservoir that is 
primarily used to collect and cool water that comes into direct contact 
with raw materials, intermediate products, by-products, waste products, 
or finished products from a phosphoric acid manufacturing plant. The 
water in the cooling pond is often used at phosphoric acid 
manufacturing plants as filter wash water, absorber water for air 
pollution control absorbers, and/or to transport phosphogypsum as 
slurry to a gypsum dewatering stack(s).
    Equivalent P2O5 feed means the quantity of 
phosphorus, expressed as phosphorus pentoxide 
(P2O5), fed to the process.
    Evaporative cooling tower means an open-water, re-circulating 
device that uses fans or natural draft to draw or force ambient air 
through the device to remove heat from process water by direct contact.
    Exceedance means a departure from an indicator range established 
for monitoring under this subpart, consistent with any averaging period 
specified for averaging the results of the monitoring.
    Existing source depends on the date that construction or 
reconstruction of an affected source commenced. A wet-process 
phosphoric acid process line, superphosphoric acid process line, 
phosphate rock dryer, phosphate rock calciner, evaporative cooling 
tower, or purified acid process line is an existing source if 
construction or reconstruction of the affected source commenced on or 
before December 27, 1996. A gypsum dewatering stack or cooling pond is 
an existing source if it meets one of two criteria:
    (1) It was constructed or reconstructed on or before August 19, 
2015; or
    (2) It was constructed or reconstructed after August 19, 2015 and 
it was not required to obtain a permit by a state authority for the 
construction or reconstruction.
    Gypsum dewatering stack means any defined geographic area 
associated with a phosphoric acid manufacturing plant in which gypsum 
is disposed of or stored, other than within a fully enclosed building, 
container, or tank.
    Gypsum dewatering stack system means the gypsum dewatering stack, 
together with all pumps, piping, ditches, drainage conveyances, water 
control structures, collection pools, cooling ponds, surge ponds, 
auxiliary holding ponds, regional holding ponds and any other 
collection or conveyance system associated with the transport of gypsum 
from the plant to the gypsum dewatering stack, its management at the 
gypsum dewatering stack, and the process wastewater return to the 
phosphoric acid production or other process.
    HAP metals mean those metals and their compounds (in particulate or 
volatile form) that are included on the list of hazardous air 
pollutants in section 112 of the Clean Air Act. HAP metals include, but 
are not limited to: Antimony, arsenic, beryllium, cadmium, chromium, 
lead, manganese, nickel, and selenium expressed as particulate matter 
as measured by the methods and procedures in this subpart or an 
approved alternative method. For the purposes of this subpart, HAP 
metals (except mercury) are expressed as particulate matter as measured 
by Method 5 at 40 CFR part 60, appendix A-3.
    New source depends on the date that construction or reconstruction 
of an affected source commences. A wet-process phosphoric acid process 
line, superphosphoric acid process line, phosphate rock dryer, 
phosphate rock calciner, evaporative cooling tower, or purified acid 
process line is a new source if construction or reconstruction of the 
affected source commenced after December 27, 1996. A gypsum dewatering 
stack or cooling pond is a new source if it meets two criteria:
    (1) It was constructed or reconstructed after August 19, 2015; and
    (2) It was required to obtain a permit by a state authority for the 
construction or reconstruction.
    Oxidation reactor means any equipment or step that uses an 
oxidizing agent (e.g., nitric acid, ammonium nitrate, or potassium 
permanganate) to treat superphosphoric acid.
    Phosphate rock calciner means the equipment used to remove moisture 
and organic matter from phosphate rock through direct or indirect 
heating.
    Phosphate rock dryer means the equipment used to reduce the 
moisture content of phosphate rock through direct or indirect heating.
    Phosphate rock feed means all material entering any phosphate rock 
dryer or phosphate rock calciner including moisture and extraneous 
material as well as the following ore materials: Fluorapatite, 
hydroxylapatite, chlorapatite, and carbonateapatite.
    Purified phosphoric acid process line means any process line that 
uses a HAP as a solvent in the separation of impurities from the 
product acid for the purposes of rendering that product suitable for 
industrial, manufacturing, or food grade uses. A purified phosphoric 
acid process line includes:

[[Page 50438]]

solvent extraction process equipment, solvent stripping and recovery 
equipment, seal tanks, carbon treatment equipment, cooling towers, 
storage tanks, pumps, and process piping.
    Raffinate stream means the aqueous stream containing the impurities 
that are removed during the purification of wet-process phosphoric acid 
using solvent extraction.
    Research and development facility means research or laboratory 
operations whose primary purpose is to conduct research and development 
into new processes and products, where the operations are under the 
close supervision of technically trained personnel, and where the 
facility is not engaged in the manufacture of products for commercial 
sale in commerce or other off-site distribution, except in a de minimis 
manner.
    Rim ditch (cell) building technique means a gypsum dewatering stack 
construction technique that utilizes inner and outer dikes to direct 
gypsum slurry flow around the perimeter of the stack before directing 
the flow and allowing settling of finer materials into the settling 
compartment. For the purpose of this definition, the rim ditch (cell) 
building technique includes the compartment startup phase when gypsum 
is deposited directly into the settling compartment in preparation for 
ditch construction as well as the step-in or terminal phases when most 
solids must be directed to the settling compartment prior to stack 
closure. Decant return ditches are not rim ditches.
    Shutdown commences when feed materials cease to be added to an 
affected source and ends when the affected source is deactivated, 
regardless of whether feed material is present in the affected source.
    Startup commences when any feed material is first introduced into 
an affected source and ends when feed material is fully loaded into the 
affected source.
    Superphosphoric acid process line means any process line that 
concentrates wet-process phosphoric acid to 66 percent or greater 
P2O5 content by weight. A superphosphoric acid 
process line includes: evaporators, hot wells, acid sumps, oxidation 
reactors, and cooling tanks.
    Total fluorides means elemental fluorine and all fluoride 
compounds, including the HAP HF, as measured by reference methods 
specified in 40 CFR part 60, appendix A, Method 13 A or B, or by 
equivalent or alternative methods approved by the Administrator 
pursuant to Sec.  63.7(f).
    Wet-process phosphoric acid process line means any process line 
manufacturing phosphoric acid by reacting phosphate rock and acid. A 
wet-process phosphoric acid process line includes: reactors, filters, 
evaporators, and hot wells.

Sec.  63.602  Standards and compliance dates.

    (a) On and after the dates specified in paragraphs (a)(1) through 
(6) of this section, for each wet-process phosphoric acid process line, 
superphosphoric acid process line, phosphate rock dryer, and phosphate 
rock calciner, you must comply with the emission limits as specified in 
paragraphs (a)(1) through (6) of this section. If a process line 
contains more than one emission point, you must sum the emissions from 
all emission points in a process line to determine compliance with the 
specified emission limits.
    (1) For each existing wet-process phosphoric acid process line, 
superphosphoric acid process line, and phosphate rock dryer that 
commenced construction or reconstruction on or before December 27, 
1996, you must comply with the emission limits specified in Table 1 to 
this subpart beginning on June 10, 2002.
    (2) For each existing phosphate rock calciner that commenced 
construction or reconstruction on or before December 27, 1996, you must 
comply with the emission limits as specified in paragraphs (a)(2)(i) 
through (iii) of this section.
    (i) You must comply with the total particulate emission limit 
specified in Table 1 to this subpart beginning on June 10, 2002.
    (ii) You must comply with the mercury emission limit specified in 
Table 1 to this subpart beginning on August 19, 2015.
    (iii) You must comply with the total fluorides emission limit 
specified in Table 1 to this subpart beginning on August 19, 2015.
    (3) For each new wet-process phosphoric acid process line, 
superphosphoric acid process line, and phosphate rock dryer that 
commences construction or reconstruction after December 27, 1996 and on 
or before August 19, 2015, you must comply with the emission limits 
specified in Table 2 to this subpart beginning on June 10, 1999 or at 
startup, whichever is later.
    (4) For each new wet-process phosphoric acid process line, 
superphosphoric acid process line, and phosphate rock dryer that 
commences construction or reconstruction after August 19, 2015, you 
must comply with the emission limits specified in Table 2 to this 
subpart immediately upon startup.
    (5) For each new phosphate rock calciner that commences 
construction or reconstruction after December 27, 1996 and on or before 
August 19, 2015, you must comply with the emission limits as specified 
in paragraphs (a)(5)(i) through (iii) of this section.
    (i) You must comply with the total particulate emission limit 
specified in Table 2 to this subpart beginning on June 10, 1999 or at 
startup, whichever is later.
    (ii) You must comply with the mercury emission limit specified in 
Table 2 to this subpart beginning on August 19, 2015, or upon startup, 
whichever is later.
    (iii) You must comply with the total fluorides emission limit 
specified in Table 2 to this subpart beginning on August 19, 2015, or 
upon startup, whichever is later.
    (6) For each new phosphate rock calciner that commences 
construction or reconstruction after August 19, 2015, you must comply 
with the emission limits specified in Table 2 to this subpart 
immediately upon startup.
    (b) For each existing purified phosphoric acid process line that 
commenced construction or reconstruction on or before December 27, 
1996, you must comply with the provisions of subpart H of this part and 
paragraphs (b)(1) through (3) of this section beginning on June 10, 
2002. For each new purified phosphoric acid process line that commences 
construction or reconstruction after December 27, 1996, you must comply 
with the provisions of subpart H of this part and paragraphs (b)(1) 
through (3) of this section beginning on June 10, 1999 or at startup, 
whichever is later.
    (1) Maintain a 30-day rolling average of daily concentration 
measurements of methyl isobutyl ketone equal to or below 20 parts per 
million by weight (ppmw) for each product acid stream.
    (2) Maintain a 30-day rolling average of daily concentration 
measurements of methyl isobutyl ketone equal to or below 30 ppmw for 
each raffinate stream.
    (3) Maintain the daily average temperature of the exit gas stream 
from the chiller stack below 50 degrees Fahrenheit.
    (c) Beginning on June 10, 2002, you must not introduce into an 
existing evaporative cooling tower that commenced construction or 
reconstruction on or before December 27, 1996, any liquid effluent from 
any absorber installed to control emissions from process equipment. 
Beginning on June 10, 1999 or at startup, whichever

[[Page 50439]]

is later, you must not introduce into a new evaporative cooling tower 
that commences construction or reconstruction after December 27, 1996, 
any liquid effluent from any absorber installed to control emissions 
from process equipment.
    (d) For each gypsum dewatering stack system, you must prepare, and 
operate in accordance with, a gypsum dewatering stack and cooling pond 
management plan that contains the information specified in paragraph 
(e) of this section beginning on August 19, 2016.
    (e) The gypsum dewatering stack and cooling pond management plan 
must include the information specified in paragraphs (e)(1) through (3) 
of this section. You must submit the gypsum dewatering stack and 
cooling pond management plan for approval to the Administrator as 
specified in paragraph (e)(4) of this section.
    (1) Location (including latitude and longitude of centroid in 
decimal degrees to four decimal places) of each gypsum dewatering stack 
and each cooling pond in the gypsum dewatering stack system.
    (2) Permitted maximum footprint acreage of each gypsum dewatering 
stack and each cooling pond in the gypsum dewatering stack system.
    (3) Control measures that you use to minimize fugitive hydrogen 
fluoride emissions from the gypsum dewatering stack system. If you 
operate one or more active gypsum dewatering stacks or cooling ponds 
that are considered new sources as defined in Sec.  63.601, then you 
must use, and include in the management plan, at least two of the 
control measures listed in paragraphs (e)(3)(i) through (vii) of this 
section for your gypsum dewatering stack system. If you only operate 
active gypsum dewatering stacks and cooling ponds that are considered 
existing sources as defined in Sec.  63.601, then you must use, and 
include in the management plan, at least one of the control measures 
listed in paragraphs (e)(3)(i) through (vii) of this section for your 
gypsum dewatering stack system.
    (i) For at least one cooling pond that is considered part of your 
gypsum dewatering stack system, you may choose to submerge the 
discharge pipe to a level below the surface of the cooling pond.
    (ii) For at least one cooling pond that is considered part of your 
gypsum dewatering stack system, you may choose to use lime (or any 
other caustic substance) to raise the pH of the liquid (e.g., the 
condensed vapors from the flash cooler and evaporators, and scrubbing 
liquid) discharged into the cooling pond. If you choose this control 
measure, then you must include in the plan the method used to raise the 
pH of the liquid discharged into the cooling pond, the target pH value 
(of the liquid discharged into the cooling pond) expected to be 
achieved by using the method, and the analyses used to determine and 
support the raise in pH.
    (iii) For all cooling ponds that are considered part of your gypsum 
dewatering stack system, you may choose to reduce the total cooling 
pond surface area based on a facility specific evaluation plan. If you 
choose this control measure, then you must include in the facility 
specific evaluation plan certified by an independent licensed 
professional engineer or similarly qualified individual. You must also 
include in the plan the method used to reduce total cooling pond 
footprint, the analyses used to determine and support the reduction in 
the total cooling pond surface area, and the amount of total cooling 
pond surface area that was reduced due to the facility specific 
evaluation plan.
    (iv) For at least one gypsum dewatering stack that is considered 
part of your gypsum dewatering stack system, you may choose to minimize 
the surface area of the gypsum pond associated with the active gypsum 
dewatering stack by using a rim ditch (cell) building technique or 
other building technique.
    (v) For at least one gypsum dewatering stack that is considered 
part of your gypsum dewatering stack system, you may choose to apply 
slaked lime to the active gypsum dewatering stack surfaces. If you 
choose this control measure, then you must include in the plan the 
method used to determine the specific locations slaked lime is applied. 
The plan must also include the methods used to determine the quantity 
of, and when to apply, slaked lime (e.g., slaked lime may be applied to 
achieve a state ambient air standard for fluorides, measured as 
hydrogen fluoride).
    (vi) For at least one gypsum dewatering stack that is considered 
part of your gypsum dewatering stack system, you may choose to apply 
soil caps and vegetation, or a synthetic cover, to a portion of side 
slopes of the active gypsum dewatering stack. If you choose this 
control measure, then you must include in the plan the method used to 
determine the specific locations of soil caps and vegetation, or 
synthetic cover; and specify the acreage and locations where soil caps 
and vegetation, or synthetic cover, is applied. The plan must also 
include a schedule describing when soil caps and vegetation, or 
synthetic cover, is to be applied.
    (vii) For all gypsum dewatering stacks that are considered part of 
your gypsum dewatering stack system, you may choose to establish 
closure requirements that at a minimum, contain requirements for the 
specified items in paragraphs (e)(3)(vii)(A) and (B) of this section.
    (A) A specific trigger mechanism for when you must begin the 
closure process on the gypsum dewatering stack; and
    (B) A requirement to install a final cover. For purposes of this 
paragraph, final cover means the materials used to cover the top and 
sides of a gypsum dewatering stack upon closure.
    (4) You must submit your plan for approval to the Administrator at 
least 6 months prior to the compliance date specified in Sec.  
63.602(d), or with the permit application for modification, 
construction, or reconstruction. The plan must include details on how 
you will implement and show compliance with the control technique(s) 
that you have selected to use. The Administrator will approve or 
disapprove your plan within 90 days after receipt of the plan. To 
change any of the information submitted in the plan, you must submit a 
revised plan 60 days before the planned change is to be implemented in 
order to allow time for review and approval by the Administrator before 
the change is implemented.
    (f) Beginning on August 19, 2015, during periods of startup and 
shutdown (as defined in Sec.  63.601), you must comply with the work 
practice specified in this paragraph in lieu of the emission limits 
specified in paragraph (a) of this section. During periods of startup 
and shutdown, you must operate any control device(s) being used at the 
affected source, monitor the operating parameters specified in Table 3 
of this subpart, and comply with the operating limits specified in 
Table 4 of this subpart.

Sec.  63.603  [Reserved]

Sec.  63.604  [Reserved]

Sec.  63.605  Operating and monitoring requirements.

    (a) For each wet-process phosphoric acid process line or 
superphosphoric acid process line subject to the provisions of this 
subpart, you must comply with the monitoring requirements specified in 
paragraphs (a)(1) and (2) of this section.
    (1) Install, calibrate, maintain, and operate a continuous 
monitoring system (CMS) according to your site-specific monitoring plan 
specified in Sec.  63.608(c). The CMS must have an accuracy of 5 percent over its operating range and

[[Page 50440]]

must determine and permanently record the mass flow of phosphorus-
bearing material fed to the process.
    (2) Maintain a daily record of equivalent 
P2O5 feed. Calculate the equivalent 
P2O5 feed by determining the total mass rate, in 
metric ton/hour of phosphorus bearing feed, using the monitoring system 
specified in paragraph (a)(1) of this section and the procedures 
specified in Sec.  63.606(f)(3).
    (b) For each phosphate rock dryer or phosphate rock calciner 
subject to the provisions of this subpart, you must comply with the 
monitoring requirements specified in paragraphs (b)(1) and (2) of this 
section.
    (1) Install, calibrate, maintain, and operate a CMS according to 
your site-specific monitoring plan specified in Sec.  63.608(c). The 
CMS must have an accuracy of 5 percent over its operating 
range and must determine and permanently record either:
    (i) The mass flow of phosphorus-bearing feed material to the 
phosphate rock dryer or calciner, or
    (ii) The mass flow of product from the phosphate rock dryer or 
calciner.
    (2) Maintain the records specified in paragraphs (b)(2)(i) and (ii) 
of this section.
    (i) If you monitor the mass flow of phosphorus-bearing feed 
material to the phosphate rock dryer or calciner as specified in 
paragraph (b)(1)(i) of this section, maintain a daily record of 
phosphate rock feed by determining the total mass rate in metric tons/
hour of phosphorus-bearing feed.
    (ii) If you monitor the mass flow of product from the phosphate 
rock dryer or calciner as specified in paragraph (b)(1)(ii) of this 
section, maintain a daily record of product by determining the total 
mass rate in metric ton/hour of product.
    (c) For each purified phosphoric acid process line, you must comply 
with the monitoring requirements specified in paragraphs (c)(1) and (2) 
of this section.
    (1) Install, calibrate, maintain, and operate a CMS according to 
your site-specific monitoring plan specified in Sec.  63.608(c). The 
CMS must continuously measure and permanently record the stack gas exit 
temperature for each chiller stack.
    (2) Measure and record the concentration of methyl isobutyl ketone 
in each product acid stream and each raffinate stream once each day.
    (d) If you use a control device(s) to comply with the emission 
limits specified in Table 1 or 2 of this subpart, you must install a 
continuous parameter monitoring system (CPMS) and comply with the 
requirements specified in paragraphs (d)(1) through (5) of this 
section.
    (1) You must monitor the operating parameter(s) applicable to the 
control device that you use as specified in Table 3 to this subpart and 
establish the applicable limit or range for the operating parameter 
limit as specified in paragraphs (d)(1)(i) and (ii) of this section, as 
applicable.
    (i) Except as specified in paragraph (d)(1)(ii) of this section, 
determine the value(s) as the arithmetic average of operating parameter 
measurements recorded during the three test runs conducted for the most 
recent performance test.
    (ii) If you use an absorber or a wet electrostatic precipitator to 
comply with the emission limits in Table 1 or 2 to this subpart and you 
monitor pressure drop across the absorber or secondary voltage for a 
wet electrostatic precipitator, you must establish allowable ranges 
using the methodology specified in paragraphs (d)(1)(ii)(A) and (B) of 
this section.
    (A) The allowable range for the daily averages of the pressure drop 
across an absorber, or secondary voltage for a wet electrostatic 
precipitator, is 20 percent of the baseline average value 
determined in paragraph (d)(1)(i) of this section. The Administrator 
retains the right to reduce the 20 percent adjustment to 
the baseline average values of operating ranges in those instances 
where performance test results indicate that a source's level of 
emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (B) As an alternative to paragraph (d)(1)(ii)(A) of this section, 
you may establish allowable ranges for the daily averages of the 
pressure drop across an absorber, or secondary voltage for an 
electrostatic precipitator, for the purpose of assuring compliance with 
this subpart using the procedures described in this paragraph. You must 
establish the allowable ranges based on the baseline average values 
recorded during previous performance tests, or the results of 
performance tests conducted specifically for the purposes of this 
paragraph. You must conduct all performance tests using the methods 
specified in Sec.  63.606. You must certify that the control devices 
and processes have not been modified since the date of the performance 
test from which you obtained the data used to establish the allowable 
ranges. When a source using the methodology of this paragraph is 
retested, you must determine new allowable ranges of baseline average 
values unless the retest indicates no change in the operating 
parameters outside the previously established ranges.
    (2) You must monitor, record, and demonstrate continuous compliance 
using the minimum frequencies specified in Table 4 to this subpart.
    (3) You must comply with the calibration and quality control 
requirements that are applicable to the operating parameter(s) you 
monitor as specified in Table 5 to this subpart.
    (4) If you use a non-regenerative adsorption system to achieve the 
mercury emission limits specified in Table 1 or 2 to this subpart, you 
must comply with the requirements specified in paragraph (e) of this 
section.
    (5) If you use a sorbent injection system to achieve the mercury 
emission limits specified in Table 1 or 2 to this subpart and you use a 
fabric filter to collect the associated particulate matter, the system 
must meet the requirements for fabric filters specified in paragraph 
(f) of this section.
    (e) If you use a non-regenerative adsorption system to achieve the 
mercury emission limits specified in Table 1 or 2 to this subpart, you 
must comply with the requirements specified in paragraphs (e)(1) 
through (3) of this section.
    (1) Determine the adsorber bed life (i.e., the expected life of the 
sorbent in the adsorption system) using the procedures specified in 
paragraphs (e)(1)(i) through (iv) of this section.
    (i) If the adsorber bed is expected (designed) to have a life of 
less than 2 years, determine the outlet concentration of mercury on a 
quarterly basis until breakthrough occurs for the first three adsorber 
bed change-outs. The adsorber bed life shall equal the average length 
of time between each of the three change-outs.
    (ii) If the adsorber bed is expected (designed) to have a life of 2 
years or greater, determine the outlet concentration of mercury on a 
semi-annual basis until breakthrough occurs for the first two adsorber 
bed change-outs. The adsorber bed life must equal the average length of 
time between each of the two change-outs.
    (iii) If more than one adsorber is operated in parallel, or there 
are several identical operating lines controlled by adsorbers, you may 
determine the adsorber bed life by measuring the outlet concentration 
of mercury from one of the adsorbers or adsorber systems rather than 
determining the bed life for each adsorber.
    (iv) The adsorber or adsorber system you select for the adsorber 
bed life test must have the highest expected inlet gas

[[Page 50441]]

mercury concentration and the highest operating rate of any adsorber in 
operation at the affected source. During the test to determine adsorber 
bed life, you must use the fuel that contains the highest level of 
mercury in any fuel-burning unit associated with the adsorption system 
being tested.
    (2) You must replace the sorbent in each adsorber on or before the 
end of the adsorbent bed life, calculated in paragraph (e)(1) of this 
section.
    (3) You must re-establish the adsorber bed life if the sorbent is 
replaced with a different brand or type, or if any process changes are 
made that would lead to a shorter bed lifetime.
    (f) Beginning August 19, 2016, if you use a fabric filter system to 
comply with the emission limits specified in Table 1 or 2 to this 
subpart, then the fabric filter must be equipped with a bag leak 
detection system that is installed, calibrated, maintained, and 
continuously operated according to the requirements in paragraphs 
(f)(1) through (10) of this section.
    (1) Install a bag leak detection sensor(s) in a position(s) that 
will be representative of the relative or absolute particulate matter 
loadings for each exhaust stack, roof vent, or compartment (e.g., for a 
positive-pressure fabric filter) of the fabric filter.
    (2) Use a bag leak detection system certified by the manufacturer 
to be capable of detecting particulate matter emissions at 
concentrations of 1 milligram per actual cubic meter (0.00044 grains 
per actual cubic feet) or less.
    (3) Use a bag leak detection system equipped with a device to 
continuously record the output signal from the system sensor.
    (4) Use a bag leak detection system equipped with a system that 
will trigger an alarm when an increase in relative particulate matter 
emissions over a preset level is detected. The alarm must be located 
such that the alert is observed readily by plant operating personnel.
    (5) Install a bag leak detection system in each compartment or cell 
for positive-pressure fabric filter systems that do not duct all 
compartments or cells to a common stack. Install a bag leak detector 
downstream of the fabric filter if a negative-pressure or induced-air 
filter system is used. If multiple bag leak detectors are required, the 
system's instrumentation and alarm may be shared among detectors.
    (6) Calibration of the bag leak detection system must, at a 
minimum, consist of establishing the baseline output level by adjusting 
the range and the averaging period of the device and establishing the 
alarm set points and the alarm delay time.
    (7) After initial adjustment, you must not adjust the sensitivity 
or range, averaging period, alarm set points, or alarm delay time 
except as established in your site-specific monitoring plan required in 
Sec.  63.608(c). In no event may the sensitivity be increased more than 
100 percent or decreased by more than 50 percent over a 365-day period 
unless such adjustment follows a complete inspection of the fabric 
filter system that demonstrates that the system is in good operating 
condition.
    (8) Operate and maintain each fabric filter and bag leak detection 
system such that the alarm does not sound more than 5 percent of the 
operating time during a 6-month period. If the alarm sounds more than 5 
percent of the operating time during a 6-month period, it is considered 
an operating parameter exceedance. Calculate the alarm time (i.e., time 
that the alarm sounds) as specified in paragraphs (f)(8)(i) through 
(iii) of this section.
    (i) If inspection of the fabric filter demonstrates that corrective 
action is not required, the alarm duration is not counted in the alarm 
time calculation.
    (ii) If corrective action is required, each alarm time is counted 
as a minimum of 1 hour.
    (iii) If it takes longer than 1 hour to initiate corrective action, 
each alarm time is counted as the actual amount of time taken to 
initiate corrective action.
    (9) If the alarm on a bag leak detection system is triggered, you 
must initiate procedures within 1 hour of an alarm to identify the 
cause of the alarm and then initiate corrective action, as specified in 
Sec.  63.608(d)(2), no later than 48 hours after an alarm. Failure to 
take these actions within the prescribed time periods is considered a 
violation.
    (10) Retain records of any bag leak detection system alarm, 
including the date, time, duration, and the percent of the total 
operating time during each 6-month period that the alarm sounds, with a 
brief explanation of the cause of the alarm, the corrective action 
taken, and the schedule and duration of the corrective action.
    (g) If you choose to directly monitor mercury emissions instead of 
using CPMS as specified in paragraph (d) of this section, then you must 
install and operate a mercury CEMS in accordance with Performance 
Specification 12A of appendix B to part 60 of this chapter, or a 
sorbent trap-based integrated monitoring system in accordance with 
Performance Specification 12B of appendix B to part 60 of this chapter. 
You must continuously monitor mercury emissions as specified in 
paragraphs (g)(1) through (4) of this section.
    (1) The span value for any mercury CEMS must include the intended 
upper limit of the mercury concentration measurement range during 
normal operation, which may be exceeded during other short-term 
conditions lasting less than 24 consecutive operating hours. However, 
the span should be at least equivalent to approximately two times the 
emissions standard. You may round the span value to the nearest 
multiple of 10 micrograms per cubic meter of total mercury.
    (2) You must operate and maintain each mercury CEMS or sorbent 
trap-based integrated monitoring system according to the quality 
assurance requirements specified in Procedure 5 of appendix F to part 
60 of this chapter.
    (3) You must conduct relative accuracy testing of mercury 
monitoring systems, as specified in Performance Specification 12A, 
Performance Specification 12B, or Procedure 5 of appendix B to part 60 
of this chapter, at normal operating conditions.
    (4) If you use a mercury CEMS, you must install, operate, 
calibrate, and maintain an instrument for continuously measuring and 
recording the exhaust gas flow rate to the atmosphere according to your 
site-specific monitoring plan specified in Sec.  63.608(c).

Sec.  63.606  Performance tests and compliance provisions.

    (a) You must conduct an initial performance test to demonstrate 
compliance with the applicable emission limits specified in Tables 1 
and 2 to this subpart, within 180 days of the applicable compliance 
date specified in Sec.  63.602.
    (b) After you conduct the initial performance test specified in 
paragraph (a) of this section, you must conduct a performance test once 
per calendar year.
    (c) For affected sources (as defined in Sec.  63.600) that have not 
operated since the previous annual performance test was conducted and 
more than 1 year has passed since the previous performance test, you 
must conduct a performance test no later than 180 days after the re-
start of the affected source according to the applicable provisions in 
Sec.  63.7(a)(2).
    (d)(1) You must conduct the performance tests specified in this 
section at representative (normal) conditions for the process. 
Representative (normal) conditions means those conditions that:
    (i) Represent the range of combined process and control measure 
conditions under which the facility expects to

[[Page 50442]]

operate (regardless of the frequency of the conditions); and
    (ii) Are likely to most challenge the emissions control measures of 
the facility with regard to meeting the applicable emission standards, 
but without creating an unsafe condition. Operations during startup, 
shutdown, and malfunction do not constitute representative (normal) 
operating conditions for purposes of conducting a performance test.
    (2) You must record the process information that is necessary to 
document the operating conditions during the test and include in such 
record an explanation to support that such conditions represent 
representative (normal) conditions. Upon request, you must make 
available to the Administrator such records as may be necessary to 
determine the conditions of performance tests.
    (e) In conducting all performance tests, you must use as reference 
methods and procedures the test methods in 40 CFR part 60, appendix A, 
or other methods and procedures as specified in this section, except as 
provided in Sec.  63.7(f).
    (f) You must determine compliance with the applicable total 
fluorides standards specified in Tables 1 and 2 to this subpart as 
specified in paragraphs (f)(1) through (3) of this section.
    (1) Compute the emission rate (E) of total fluorides for each run 
using Equation AA-1:
[GRAPHIC] [TIFF OMITTED] TR19AU15.000

Where:

E = Emission rate of total fluorides, gram/metric ton (pound/ton) of 
equivalent P2O5 feed.
Ci = Concentration of total fluorides from emission point 
``i,'' milligram/dry standard cubic meter (milligram/dry standard 
cubic feet).
Qi = Volumetric flow rate of effluent gas from emission 
point ``i,'' dry standard cubic meter/hour (dry standard cubic feet/
hour).
N = Number of emission points associated with the affected facility.
P = Equivalent P2O5 feed rate, metric ton/hour 
(ton/hour).
K = Conversion factor, 1000 milligram/gram (453,600 milligram/
pound).

    (2) You must use Method 13A or 13B (40 CFR part 60, appendix A) to 
determine the total fluorides concentration (Ci) and the 
volumetric flow rate (Qi) of the effluent gas at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. The sampling volume for each run at each 
emission point must be at least 0.85 dscm (30 dscf). If Method 13B is 
used, the fusion of the filtered material described in Section 7.3.1.2 
and the distillation of suitable aliquots of containers 1 and 2, 
described in section 7.3.3 and 7.3.4 in Method 13 A, may be omitted.
    (3) Compute the equivalent P2O5 feed rate (P) 
using Equation AA-2:
[GRAPHIC] [TIFF OMITTED] TR19AU15.001

Where:

P = P2O5 feed rate, metric ton/hr (ton/hour).
Mp = Total mass flow rate of phosphorus-bearing feed, 
metric ton/hour (ton/hour).
Rp = P2O5 content, decimal 
fraction.

    (i) Determine the mass flow rate (Mp) of the phosphorus-
bearing feed using the measurement system described in Sec.  63.605(a).
    (ii) Determine the P2O5 content 
(Rp) of the feed using, as appropriate, the following 
methods specified in Methods Used and Adopted By The Association of 
Florida Phosphate Chemists (incorporated by reference, see Sec.  63.14) 
where applicable:
    (A) Section IX, Methods of Analysis for Phosphate Rock, No. 1 
Preparation of Sample.
    (B) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method A--Volumetric 
Method.
    (C) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method B--Gravimetric 
Quimociac Method.
    (D) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method C--
Spectrophotometric Method.
    (E) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A--Volumetric 
Method.
    (F) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B--Gravimetric 
Quimociac Method.
    (G) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method C--
Spectrophotometric Method.
    (g) You must demonstrate compliance with the applicable particulate 
matter standards specified in Tables 1 and 2 to this subpart as 
specified in paragraphs (g)(1) through (3) of this section.
    (1) Compute the emission rate (E) of particulate matter for each 
run using Equation AA-3:
[GRAPHIC] [TIFF OMITTED] TR19AU15.002

Where:

E = Emission rate of particulate matter, kilogram/megagram (pound/
ton) of phosphate rock feed.
C = Concentration of particulate matter, gram/dry standard cubic 
meter (gram/dry standard cubic feet).
Q = Volumetric flow rate of effluent gas, dry standard cubic meter/
hour (dry standard cubic feet/hour).
P = Phosphate rock feed rate, megagram/hour (ton/hour).
K = Conversion factor, 1000 grams/kilogram (453.6 grams/pound).

    (2) Use Method 5 at 40 CFR part 60, appendix A-3 to determine the 
particulate matter concentration (C) and volumetric flow rate (Q) of 
the effluent gas. Except as specified in paragraph (h) of this section, 
the sampling time and

[[Page 50443]]

sample volume for each run must be at least 60 minutes and 0.85 dry 
standard cubic meter (30 dry standard cubic feet).
    (3) Use the CMS described in Sec.  63.605(b) to determine the 
phosphate rock feed rate (P) for each run.
    (h) To demonstrate compliance with the particulate matter standards 
for phosphate rock calciners specified in Tables 1 and 2 to this 
subpart, you must use Method 5 at 40 CFR part 60, appendix A-3 to 
determine the particulate matter concentration. The sampling volume for 
each test run must be at least 1.70 dry standard cubic meter.
    (i) To demonstrate compliance with the mercury emission standards 
for phosphate rock calciners specified in Tables 1 and 2 to this 
subpart, you must use Method 30B at 40 CFR part 60, appendix A-8 to 
determine the mercury concentration, unless you use a CEMS to 
demonstrate compliance. If you use a non-regenerative adsorber to 
control mercury emissions, you must use this test method to determine 
the expected bed life as specified in Sec.  63.605(e)(1).
    (j) If you choose to monitor the mass flow of product from the 
phosphate rock dryer or calciner as specified in Sec.  
63.605(b)(1)(ii), you must either:
    (1) Simultaneously monitor the feed rate and output rate of the 
phosphate rock dryer or calciner during the performance test, or
    (2) Monitor the output rate and the input and output moisture 
contents of the phosphate rock dryer or calciner during the performance 
test and calculate the corresponding phosphate rock dryer or calciner 
input rate.
    (k) For sorbent injection systems, you must conduct the performance 
test at the outlet of the fabric filter used for sorbent collection. 
You must monitor and record operating parameter values for the fabric 
filter during the performance test. If the sorbent is replaced with a 
different brand or type of sorbent than was used during the performance 
test, you must conduct a new performance test.
    (l) If you use a mercury CEMS as specified in Sec.  63.605(g), or 
paragraph (i) of this section, you must demonstrate initial compliance 
based on the first 30 operating days during which you operate the 
affected source using a CEMS. You must obtain hourly mercury 
concentration and stack gas volumetric flow rate data.
    (m) If you use a CMS, you must conduct a performance evaluation, as 
specified in Sec.  63.8(e), in accordance with your site-specific 
monitoring plan in Sec.  63.608(c). For fabric filters, you must 
conduct a performance evaluation of the bag leak detection system 
consistent with the guidance provided in Office Of Air Quality Planning 
And Standards (OAQPS), Fabric Filter Bag Leak Detection Guidance 
(incorporated by reference, see Sec.  63.14). You must record the 
sensitivity of the bag leak detection system to detecting changes in 
particulate matter emissions, range, averaging period, and alarm set 
points during the performance test.

Sec.  63.607  Notification, recordkeeping, and reporting requirements.

    (a) You must comply with the notification requirements specified in 
Sec.  63.9. During the most recent performance test, if you demonstrate 
compliance with the emission limit while operating your control device 
outside the previously established operating limit, you must establish 
a new operating limit based on that most recent performance test and 
notify the Administrator that the operating limit changed based on data 
collected during the most recent performance test. When a source is 
retested and the performance test results are submitted to the 
Administrator pursuant to paragraph (b)(1) of this section, Sec.  
63.7(g)(1), or Sec.  63.10(d)(2), you must indicate whether the 
operating limit is based on the new performance test or the previously 
established limit. Upon establishment of a new operating limit, you 
must thereafter operate under the new operating limit. If the 
Administrator determines that you did not conduct the compliance test 
in accordance with the applicable requirements or that the operating 
limit established during the performance test does not correspond to 
representative (normal) conditions, you must conduct a new performance 
test and establish a new operating limit.
    (b) You must comply with the reporting and recordkeeping 
requirements in Sec.  63.10 as specified in paragraphs (b)(1) through 
(5) of this section.
    (1) You must comply with the general recordkeeping requirements in 
Sec.  63.10(b)(1).
    (2) As required by Sec.  63.10(d), you must report the results of 
the initial and subsequent performance tests as part of the 
notification of compliance status required in Sec.  63.9(h). You must 
verify in the performance test reports that the operating limits for 
each process have not changed or provide documentation of revised 
operating limits established according to Sec.  63.605, as applicable. 
In the notification of compliance status, you must also:
    (i) Certify to the Administrator annually that you have complied 
with the evaporative cooling tower requirements specified in Sec.  
63.602(c).
    (ii) Submit analyses and supporting documentation demonstrating 
conformance with the Office Of Air Quality Planning And Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance (incorporated by 
reference, see Sec.  63.14) and specifications for bag leak detection 
systems as part of the notification of compliance status report.
    (iii) Submit the gypsum dewatering stack and cooling pond 
management plan specified in Sec.  63.602(e).
    (iv) If you elect to demonstrate compliance by following the 
procedures in Sec.  63.605(d)(1)(ii)(B), certify to the Administrator 
annually that the control devices and processes have not been modified 
since the date of the performance test from which you obtained the data 
used to establish the allowable ranges.
    (v) Each time a gypsum dewatering stack is closed, certify to the 
Administrator within 90 days of closure, that the final cover of the 
closed gypsum dewatering stack is a drought resistant vegetative cover 
that includes a barrier soil layer that will sustain vegetation.
    (3) As required by Sec.  63.10(e)(3), you must submit an excess 
emissions report for any exceedance of an emission limit, work practice 
standard, or operating parameter limit if the total duration of the 
exceedances for the reporting period is 1 percent of the total 
operating time for the reporting period or greater. The report must 
contain the information specified in Sec.  63.10 and paragraph (b)(4) 
of this section. When exceedances of an emission limit or operating 
parameter have not occurred, you must include such information in the 
report. You must submit the report semiannually and the report must be 
delivered or postmarked by the 30th day following the end of the 
calendar half. If you report exceedances, you must submit the excess 
emissions report quarterly until a request to reduce reporting 
frequency is approved as described in Sec.  63.10(e)(3)(ii).
    (4) In the event that an affected unit fails to meet an applicable 
standard, record and report the following information for each failure:
    (i) The date, time and duration of the failure.
    (ii) A list of the affected sources or equipment for which a 
failure occurred.
    (iii) An estimate of the volume of each regulated pollutant emitted 
over any emission limit.
    (iv) A description of the method used to estimate the emissions.
    (v) A record of actions taken to minimize emissions in accordance 
with Sec.  63.608(b), and any corrective actions

[[Page 50444]]

taken to return the affected unit to its normal or usual manner of 
operation.
    (5) You must submit a summary report containing the information 
specified in Sec.  63.10(e)(3)(vi). You must submit the summary report 
semiannually and the report must be delivered or postmarked by the 30th 
day following the end of the calendar half.
    (c) Your records must be in a form suitable and readily available 
for expeditious review. You must keep each record for 5 years following 
the date of each recorded action. You must keep each record on site, or 
accessible from a central location by computer or other means that 
instantly provides access at the site, for at least 2 years after the 
date of each recorded action. You may keep the records off site for the 
remaining 3 years.
    (d) In computing averages to determine compliance with this 
subpart, you must exclude the monitoring data specified in paragraphs 
(d)(1) and (2) of this section.
    (1) Periods of non-operation of the process unit;
    (2) Periods of no flow to a control device; and any monitoring data 
recorded during CEMS or continuous parameter monitoring system (CPMS) 
breakdowns, out-of-control periods, repairs, maintenance periods, 
instrument adjustments or checks to maintain precision and accuracy, 
calibration checks, and zero (low-level), mid-level (if applicable), 
and high-level adjustments.
    (e) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2) required by this subpart, you must 
submit the results of the performance tests, including any associated 
fuel analyses, following the procedure specified in either paragraph 
(e)(1) or (2) of this section.
    (1) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(http://www.epa.gov/ttn/chief/ert/index.html), you must submit the 
results of the performance test to the EPA via the Compliance and 
Emissions Data Reporting Interface (CEDRI). CEDRI can be accessed 
through the EPA's Central Data Exchange (CDX) (http://cdx.epa.gov/epa_home.asp). Performance test data must be submitted in a file format 
generated through the use of the EPA's ERT. Alternatively, you may 
submit performance test data in an electronic file format consistent 
with the extensible markup language (XML) schema listed on the EPA's 
ERT Web site once the XML schema is available. If you claim that some 
of the performance test information being submitted is confidential 
business information (CBI), you must submit a complete file generated 
through the use of the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT Web site, 
including information claimed to be CBI, on a compact disc, flash 
drive, or other commonly used electronic storage media to the EPA. The 
electronic media must be clearly marked as CBI and mailed to U.S. EPA/
OAPQS/CORE CBI Office, Attention: Group Leader, Measurement Policy 
Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same ERT or 
alternate file with the CBI omitted must be submitted to the EPA via 
the EPA's CDX as described earlier in this paragraph.
    (2) For data collected using test methods that are not supported by 
the EPA's ERT as listed on the EPA's ERT Web site, you must submit the 
results of the performance test to the Administrator at the appropriate 
address listed in Sec.  63.13.
    (f) Within 60 days after the date of completing each continuous 
emissions monitoring system performance evaluation (as defined in Sec.  
63.2), you must submit the results of the performance evaluation 
following the procedure specified in either paragraph (f)(1) or (2) of 
this section.
    (1) For performance evaluations of continuous monitoring systems 
measuring relative accuracy test audit (RATA) pollutants that are 
supported by the EPA's ERT as listed on the EPA's ERT Web site, you 
must submit the results of the performance evaluation to the EPA via 
the CEDRI. (CEDRI can be accessed through the EPA's CDX.) Performance 
evaluation data must be submitted in a file format generated through 
the use of the EPA's ERT. Alternatively, you may submit performance 
evaluation data in an electronic file format consistent with the XML 
schema listed on the EPA's ERT Web site once the XML schema is 
available. If you claim that some of the performance evaluation 
information being transmitted is CBI, you must submit a complete file 
generated through the use of the EPA's ERT or an alternate electronic 
file consistent with the XML schema listed on the EPA's ERT Web site, 
including information claimed to be CBI, on a compact disc, flash 
drive, or other commonly used electronic storage media to the EPA. The 
electronic storage media must be clearly marked as CBI and mailed to 
U.S. EPA/OAPQS/CORE CBI Office, Attention: Group Leader, Measurement 
Policy Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same 
ERT or alternate file with the CBI omitted must be submitted to the EPA 
via the EPA's CDX as described earlier in this paragraph.
    (2) For any performance evaluations of continuous monitoring 
systems measuring RATA pollutants that are not supported by the EPA's 
ERT as listed on the EPA's ERT Web site, you must submit the results of 
the performance evaluation to the Administrator at the appropriate 
address listed in Sec.  63.13.

Sec.  63.608  General requirements and applicability of general 
provisions of this part.

    (a) You must comply with the general provisions in subpart A of 
this part as specified in appendix A to this subpart.
    (b) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. The general duty 
to minimize emissions does not require you to make any further efforts 
to reduce emissions if levels required by this standard have been 
achieved. Determination by the Administrator of whether a source is 
operating in compliance with operation and maintenance requirements 
will be based on information available to the Administrator that may 
include, but is not limited to, monitoring results, review of operation 
and maintenance procedures, review of operation and maintenance 
records, and inspection of the source.
    (c) For each CMS (including CEMS or CPMS) used to demonstrate 
compliance with any applicable emission limit or work practice, you 
must develop, and submit to the Administrator for approval upon 
request, a site-specific monitoring plan according to the requirements 
specified in paragraphs (c)(1) through (3) of this section. You must 
submit the site-specific monitoring plan, if requested by the 
Administrator, at least 60 days before the initial performance 
evaluation of the CMS. The requirements of this paragraph also apply if 
a petition is made to the Administrator for alternative monitoring 
parameters under Sec.  63.8(f).
    (1) You must include the information specified in paragraphs 
(c)(1)(i) through (vi) of this section in the site-specific monitoring 
plan.
    (i) Location of the CMS sampling probe or other interface. You must 
include a justification demonstrating that the sampling probe or other 
interface is at a measurement location relative to each affected 
process unit such that the measurement is representative of control of 
the exhaust

[[Page 50445]]

emissions (e.g., on or downstream of the last control device).
    (ii) Performance and equipment specifications for the sample 
interface, the pollutant concentration or parametric signal analyzer, 
and the data collection and reduction systems.
    (iii) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations).
    (iv) Ongoing operation and maintenance procedures in accordance 
with the general requirements of Sec.  63.8(c)(1)(ii), (c)(3), 
(c)(4)(ii), and Table 4 to this subpart.
    (v) Ongoing data quality assurance procedures in accordance with 
the general requirements of Sec.  63.8(d)(1) and (2) and Table 5 to 
this subpart.
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c), (e)(1), and (e)(2)(i).
    (2) You must include a schedule for conducting initial and 
subsequent performance evaluations in the site-specific monitoring 
plan.
    (3) You must keep the site-specific monitoring plan on site for the 
life of the affected source or until the affected source is no longer 
subject to the provisions of this part, to be made available for 
inspection, upon request, by the Administrator. If you revise the site-
specific monitoring plan, you must keep previous (i.e., superseded) 
versions of the plan on site to be made available for inspection, upon 
request, by the Administrator, for a period of 5 years after each 
revision to the plan. You must include the program of corrective action 
required under Sec.  63.8(d)(2) in the plan.
    (d) For each bag leak detection system installed to comply with the 
requirements specified in Sec.  63.605(f), you must include the 
information specified in paragraphs (d)(1) and (2) of this section in 
the site-specific monitoring plan specified in paragraph (c) of this 
section.
    (1) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations), including how the alarm set point will be 
established.
    (2) A corrective action plan describing corrective actions to be 
taken and the timing of those actions when the bag leak detection alarm 
sounds. Corrective actions may include, but are not limited to, the 
actions specified in paragraphs (d)(2)(i) through (vi) of this section.
    (i) Inspecting the fabric filter for air leaks, torn or broken bags 
or filter media, or any other conditions that may cause an increase in 
regulated material emissions.
    (ii) Sealing off defective bags or filter media.
    (iii) Replacing defective bags or filter media or otherwise 
repairing the control device.
    (iv) Sealing off a defective fabric filter compartment.
    (v) Cleaning the bag leak detection system probe or otherwise 
repairing the bag leak detection system.
    (vi) Shutting down the process controlled by the fabric filter.

Sec.  63.609  [Reserved]

Sec.  63.610  Exemption from new source performance standards.

    Any affected source subject to the provisions of this subpart is 
exempted from any otherwise applicable new source performance standard 
contained in 40 CFR part 60, subpart T, subpart U, or subpart NN. To be 
exempt, a source must have a current operating permit pursuant to title 
V of the Clean Air Act and the source must be in compliance with all 
requirements of this subpart. For each affected source, this exemption 
is effective upon the date that you demonstrate to the Administrator 
that the requirements of Sec. Sec.  63.605 and 63.606 have been met.

Sec.  63.611  Implementation and enforcement.

    (a) This subpart is implemented and enforced by the U.S. EPA, or a 
delegated authority such as the applicable state, local, or Tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
state, local, or Tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out if 
implementation and enforcement of this subpart is delegated to a state, 
local, or Tribal agency.
    (b) The authorities specified in paragraphs (b)(1) through (5) of 
this section are retained by the Administrator of U.S. EPA and cannot 
be delegated to State, local, or Tribal agencies.
    (1) Approval of alternatives to the requirements in Sec. Sec.  
63.600, 63.602, 63.605, and 63.610.
    (2) Approval of requests under Sec. Sec.  63.7(e)(2)(ii) and 63.7 
(f) for alternative requirements or major changes to the test methods 
specified in this subpart, as defined in Sec.  63.90.
    (3) Approval of requests under Sec.  63.8(f) for alternative 
requirements or major changes to the monitoring requirements specified 
in this subpart, as defined in Sec.  63.90.
    (4) Waiver or approval of requests under Sec.  63.10(f) for 
alternative requirements or major changes to the recordkeeping and 
reporting requirements specified in this subpart, as defined in Sec.  
63.90.
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

                      Table 1 to Subpart AA of Part 63--Existing Source Emission Limits a b
----------------------------------------------------------------------------------------------------------------
                                          You must meet the emission limits for the specified pollutant . . .
 For the following existing sources . --------------------------------------------------------------------------
                 . .                       Total fluorides         Total particulate             Mercury
----------------------------------------------------------------------------------------------------------------
Wet-Process Phosphoric Acid Line.....  0.020 lb/ton of
                                        equivalent P2O5 feed.
Superphosphoric Acid Process Line \c\  0.010 lb/ton of
                                        equivalent P2O5 feed.
Superphosphoric Acid Submerged Line    0.20 lb/ton of
 with a Submerged Combustion Process.   equivalent P2O5 feed.
Phosphate Rock Dryer.................  .......................  0.2150 lb/ton of
                                                                 phosphate rock feed.
Phosphate Rock Calciner..............  9.0E-04 lb/ton of rock   0.181 g/dscm...........  0.14 mg/dscm corrected
                                        feed \d\.                                         to 3 percent oxygen
                                                                                          \d\
----------------------------------------------------------------------------------------------------------------
\a\ The existing source compliance date is June 10, 2002, except as noted.
\b\ During periods of startup and shutdown, for emission limits stated in terms of pounds of pollutant per ton
  of feed, you are subject to the work practice standards specified in Sec.   63.602(f).
\c\ Beginning on August 19, 2016, you must include oxidation reactors in superphosphoric acid process lines when
  determining compliance with the total fluorides limit.
\d\ Compliance date is August 19, 2015.

[[Page 50446]]

                        Table 2 to Subpart AA of Part 63--New Source Emission Limits a b
----------------------------------------------------------------------------------------------------------------
                                          You must meet the emissions limits for the specified pollutant . . .
 For the following new sources . . .  --------------------------------------------------------------------------
                                           Total fluorides         Total particulate             Mercury
----------------------------------------------------------------------------------------------------------------
Wet-Process Phosphoric Acid Line.....  0.0135 lb/ton of                                  .......................
                                        equivalent P2O5 feed.
Superphosphoric Acid Process Line \c\  0.00870 lb/ton of
                                        equivalent P2O5 feed.
Phosphate Rock Dryer.................  .......................  0.060 lb/ton of          .......................
                                                                 phosphate rock feed.
Phosphate Rock Calciner..............  9.0E-04 lb/ton of rock   0.092 g/dscm...........  0.014 mg/dscm corrected
                                        feed.                                             to 3 percent oxygen
----------------------------------------------------------------------------------------------------------------
\a\ The new source compliance dates are based on date of construction or reconstruction as specified in Sec.
  63.602(a).
\b\ During periods of startup and shutdown, for emission limits stated in terms of pounds of pollutant per ton
  of feed, you are subject to the work practice standards specified in Sec.   63.602(f).
\c\ Beginning on August 19, 2016, you must include oxidation reactors in superphosphoric acid process lines when
  determining compliance with the total fluorides limit.

                   Table 3 to Subpart AA of Part 63--Monitoring Equipment Operating Parameters
----------------------------------------------------------------------------------------------------------------
                                                                  And you must monitor .
           You must . . .                      If . . .                     . .                  And . . .
----------------------------------------------------------------------------------------------------------------
                                            Absorbers (Wet Scrubbers)
----------------------------------------------------------------------------------------------------------------
Install a continuous parameter       Your absorber is designed    Influent liquid flow..
 monitoring system (CPMS) for         and operated with pressure
 liquid flow at the inlet of the      drops of 5 inches of water
 absorber.                            column or more; and you
                                      choose to monitor only the
                                      influent liquid flow,
                                      rather than the liquid-to-
                                      gas ratio.
Install CPMS for liquid and gas      Your absorber is designed    Liquid-to-gas ratio as  You must measure the
 flow at the inlet of the absorber.   and operated with pressure   determined by           gas stream by:
                                      drops of 5 inches of water   dividing the influent  Measuring the gas
                                      column or less; or.          liquid flow rate by     stream flow at the
                                     Your absorber is designed     the inlet gas flow      absorber inlet; or
                                      and operated with pressure   rate. The units of     Using the design
                                      drops of 5 inches of water   measure must be         blower capacity, with
                                      column or more, and you      consistent with those   appropriate
                                      choose to monitor the        used to calculate       adjustments for
                                      liquid-to-gas ratio,         this ratio during the   pressure drop.
                                      rather than only the         performance test.
                                      influent liquid flow, and
                                      you want the ability to
                                      lower liquid flow with
                                      changes in gas flow.
Install CPMS for pressure at the     Your absorber is designed    Pressure drop through   You may measure the
 gas stream inlet and outlet of the   and operated with pressure   the absorber.           pressure of the inlet
 absorber.                            drops of 5 inches of water                           gas using amperage on
                                      column or more.                                      the blower if a
                                                                                           correlation between
                                                                                           pressure and amperage
                                                                                           is established
----------------------------------------------------------------------------------------------------------------
                                                Sorbent Injection
----------------------------------------------------------------------------------------------------------------
Install a CPMS for flow rate.......  ...........................  Sorbent injection rate
Install a CPMS for flow rate.......  ...........................  Sorbent injection
                                                                   carrier gas flow rate.
----------------------------------------------------------------------------------------------------------------
                                         Wet Electrostatic Precipitators
----------------------------------------------------------------------------------------------------------------
Install secondary voltage meter....  You control mercury or       Secondary voltage.....
                                      metal HAP (particulate
                                      matter) using an
                                      electrostatic precipitator.
----------------------------------------------------------------------------------------------------------------

 Table 4 to Subpart AA of Part 63--Operating Parameters, Operating Limits and Data Monitoring, Recordkeeping and
                                             Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                                               And you must monitor, record, and demonstrate
                                                           continuous compliance using these minimum frequencies
  For the operating parameter    You must establish the                            . . .
     applicable to you, as         following operating   -------------------------------------------------------
  specified in Table 3 . . .           limit . . .                                               Data averaging
                                                           Data measurement   Data  recording      period for
                                                                                                   compliance
----------------------------------------------------------------------------------------------------------------
                                            Absorbers (Wet Scrubbers)
----------------------------------------------------------------------------------------------------------------
Influent liquid flow..........  Minimum inlet liquid      Continuous.......  Every 15 minutes.  Daily.
                                 flow.
Influent liquid flow rate and   Minimum influent liquid-  Continuous.......  Every 15 minutes.  Daily.
 gas stream flow rate.           to-gas ratio.

[[Page 50447]]

 
Pressure drop.................  Pressure drop range.....  Continuous.......  Every 15 minutes.  Daily.
----------------------------------------------------------------------------------------------------------------
                                                Sorbent Injection
----------------------------------------------------------------------------------------------------------------
Sorbent injection rate........  Minimum injection rate..  Continuous.......  Every 15 minutes.  Daily.
Sorbent injection carrier gas   Minimum carrier gas flow  Continuous.......  Every 15 minutes.  Daily.
 flow rate.                      rate.
----------------------------------------------------------------------------------------------------------------
                                                 Fabric Filters
----------------------------------------------------------------------------------------------------------------
Alarm time....................  Maximum alarm time is     Continuous.......  Each date and      Maximum alarm
                                 not established on a                         time of alarm      time specified
                                 site-specific basis but                      start and stop.    in Sec.
                                 is specified in Sec.                                            63.605(f)(9).
                                 63.605(f)(9).
----------------------------------------------------------------------------------------------------------------
                                         Wet Electrostatic Precipitator
----------------------------------------------------------------------------------------------------------------
Secondary voltage.............  Secondary voltage range.  Continuous.......  Every 15 minutes.  Daily.
----------------------------------------------------------------------------------------------------------------

     Table 5 to Subpart AA of Part 63--Calibration and Quality Control Requirements for Continuous Parameter
                                            Monitoring System (CPMS)
----------------------------------------------------------------------------------------------------------------
                                                        Your accuracy requirements       And your calibration
         If you monitor this parameter . . .                     are . . .              requirements are . . .
----------------------------------------------------------------------------------------------------------------
Temperature..........................................  1 percent over    Performance evaluation
                                                        the normal range of           annually and following any
                                                        temperature measured or 2.8   period of more than 24
                                                        degrees Celsius (5 degrees    hours throughout which the
                                                        Fahrenheit), whichever is     temperature exceeded the
                                                        greater, for non-cryogenic    maximum rated temperature
                                                        temperature ranges.           of the sensor, or the data
                                                       2.5 percent over   recorder was off scale.
                                                        the normal range of          Visual inspections and
                                                        temperature measured or 2.8   checks of CPMS operation
                                                        degrees Celsius (5 degrees    every 3 months, unless the
                                                        Fahrenheit), whichever is     CPMS has a redundant
                                                        greater, for cryogenic        temperature sensor.
                                                        temperature ranges.          Selection of a
                                                                                      representative measurement
                                                                                      location.
Flow Rate............................................  5 percent over    Performance evaluation
                                                        the normal range of flow      annually and following any
                                                        measured or 1.9 liters per    period of more than 24
                                                        minute (0.5 gallons per       hours throughout which the
                                                        minute), whichever is         flow rate exceeded the
                                                        greater, for liquid flow      maximum rated flow rate of
                                                        rate.                         the sensor, or the data
                                                       5 percent over     recorder was off scale.
                                                        the normal range of flow     Checks of all mechanical
                                                        measured or 280 liters per    connections for leakage
                                                        minute (10 cubic feet per     monthly.
                                                        minute), whichever is        Visual inspections and
                                                        greater, for gas flow rate.   checks of CPMS operation
                                                       5 percent over     every 3 months, unless the
                                                        the normal range measured     CPMS has a redundant flow
                                                        for mass flow rate.           sensor.
                                                                                     Selection of a
                                                                                      representative measurement
                                                                                      location where swirling
                                                                                      flow or abnormal velocity
                                                                                      distributions due to
                                                                                      upstream and downstream
                                                                                      disturbances at the point
                                                                                      of measurement are
                                                                                      minimized.
Pressure.............................................  5 percent over    Checks for obstructions
                                                        the normal range measured     (e.g., pressure tap
                                                        or 0.12 kilopascals (0.5      pluggage) at least once
                                                        inches of water column),      each process operating
                                                        whichever is greater.         day.
                                                                                     Performance evaluation
                                                                                      annually and following any
                                                                                      period of more than 24
                                                                                      hours throughout which the
                                                                                      pressure exceeded the
                                                                                      maximum rated pressure of
                                                                                      the sensor, or the data
                                                                                      recorder was off scale.
                                                                                     Checks of all mechanical
                                                                                      connections for leakage
                                                                                      monthly. Visual inspection
                                                                                      of all components for
                                                                                      integrity, oxidation and
                                                                                      galvanic corrosion every 3
                                                                                      months, unless the CPMS
                                                                                      has a redundant pressure
                                                                                      sensor.
                                                                                     Selection of a
                                                                                      representative measurement
                                                                                      location that minimizes or
                                                                                      eliminates pulsating
                                                                                      pressure, vibration, and
                                                                                      internal and external
                                                                                      corrosion.

[[Page 50448]]

 
Sorbent Injection Rate...............................  5 percent over    Performance evaluation
                                                        the normal range measured.    annually.
                                                                                     Visual inspections and
                                                                                      checks of CPMS operation
                                                                                      every 3 months, unless the
                                                                                      CPMS has a redundant
                                                                                      sensor.
                                                                                     Select a representative
                                                                                      measurement location that
                                                                                      provides measurement of
                                                                                      total sorbent injection.
Secondary voltage....................................  1kV.............  ...........................
----------------------------------------------------------------------------------------------------------------

 Appendix A to Subpart AA of Part 63--Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart
                                                       AA
----------------------------------------------------------------------------------------------------------------
          40 CFR citation                  Requirement           Applies to subpart AA            Comment
----------------------------------------------------------------------------------------------------------------
Sec.   63.1(a)(1) through (4)......  General Applicability..  Yes.......................  None.
Sec.   63.1(a)(5)..................  .......................  No........................  [Reserved].
Sec.   63.1(a)(6)..................  Contact information....  Yes.......................  None.
Sec.   63.1(a)(7)-(9)..............  .......................  No........................  [Reserved].
Sec.   63.1(a)(10) through (12)....  Time periods...........  Yes.......................  None.
Sec.   63.1(b).....................  Initial Applicability    Yes.......................  None.
                                      Determination.
Sec.   63.1(c)(1)..................  Applicability After      Yes.......................  None.
                                      Standard Established.
Sec.   63.1(c)(2)..................  Permits................  Yes.......................  Some plants may be
                                                                                           area sources.
Sec.   63.1(c)(3)-(4)..............  .......................  No........................  [Reserved].
Sec.   63.1(c)(5)..................  Area to Major source     Yes.......................  None.
                                      change.
Sec.   63.1(d).....................  .......................  No........................  [Reserved].
Sec.   63.1(e).....................  Applicability of Permit  Yes.......................  None.
                                      Program.
Sec.   63.2........................  Definitions............  Yes.......................  Additional definitions
                                                                                           in Sec.   63.601.
Sec.   63.3........................  Units and Abbreviations  Yes.......................  None.
Sec.   63.4(a)(1) and (2)..........  Prohibited Activities..  Yes.......................  None.
Sec.   63.4(a)(3) through (5)......  .......................  No........................  [Reserved].
Sec.   63.4(b) and (c).............  Circumvention/           Yes.......................  None.
                                      Fragmentation.
Sec.   63.5(a).....................  Construction/            Yes.......................  None.
                                      Reconstruction
                                      Applicability.
Sec.   63.5(b)(1)..................  Existing, New,           Yes.......................  None.
                                      Reconstructed Sources
                                      Requirements.
Sec.   63.5(b)(2)..................  .......................  No........................  [Reserved].
Sec.   63.5(b)(3), (4), and (6)....  Construction/            Yes.......................  None.
                                      Reconstruction
                                      approval and
                                      notification.
Sec.   63.5(b)(5)..................  .......................  No........................  [Reserved].
Sec.   63.5(c).....................  .......................  No........................  [Reserved].
Sec.   63.5(d).....................  Application for          Yes.......................  None.
                                      Approval of
                                      Construction/
                                      Reconstruction.
Sec.   63.5(e).....................  Approval of              Yes.......................  None.
                                      Construction/
                                      Reconstruction.
Sec.   63.5(f).....................  Approval of              Yes.......................  None.
                                      Construction/
                                      Reconstruction Based
                                      on State Review.
Sec.   63.6(a).....................  Compliance with          Yes.......................  None.
                                      Standards and
                                      Maintenance
                                      Applicability.
Sec.   63.6(b)(1) through (5)......  New and Reconstructed    Yes.......................  See also Sec.
                                      Sources Dates.                                       63.602.
Sec.   63.6(b)(6)..................  .......................  No........................  [Reserved].
Sec.   63.6(b)(7)..................  Area to major source     Yes.......................  None.
                                      change.
Sec.   63.6(c)(1)and (2)...........  Existing Sources Dates.  Yes.......................  Sec.   63.602
                                                                                           specifies dates.
Sec.   63.6(c)(3) and (4)..........  .......................  No........................  [Reserved].
Sec.   63.6(c)(5)..................  Area to major source     Yes.......................  None.
                                      change.
Sec.   63.6(d).....................  .......................  No........................  [Reserved].
Sec.   63.6(e)(1)(i) and (ii)......  Operation & Maintenance  No........................  See Sec.   63.608(b)
                                      Requirements.                                        for general duty
                                                                                           requirement.
Sec.   63.6(e)(iii)................  .......................  Yes.......................  None.
Sec.   63.6(e)(2)..................  .......................  No........................  [Reserved].
Sec.   63.6(e)(3)..................  Startup, Shutdown, and   No........................  None.
                                      Malfunction Plan.
Sec.   63.6(f).....................  Compliance with          No........................  See general duty at
                                      Emission Standards.                                  Sec.   63.608(b).
Sec.   63.6(g).....................  Alternative Standard...  Yes.......................  None.
Sec.   63.6(h).....................  Compliance with Opacity/ No........................  Subpart AA does not
                                      VE Standards.                                        include VE/opacity
                                                                                           standards.
Sec.   63.6(i)(1) through (14).....  Extension of Compliance  Yes.......................  None.
Sec.   63.6(i)(15).................  .......................  No........................  [Reserved].
Sec.   63.6(i)(16).................  .......................  Yes.......................  None.
Sec.   63.6(j).....................  Exemption from           Yes.......................  None.
                                      Compliance.
Sec.   63.7(a).....................  Performance Test         Yes.......................  None.
                                      Requirements
                                      Applicability.

[[Page 50449]]

 
Sec.   63.7(b).....................  Notification...........  Yes.......................  None.
Sec.   63.7(c).....................  Quality Assurance/Test   Yes.......................  None.
                                      Plan.
Sec.   63.7(d).....................  Testing Facilities.....  Yes.......................  None.
Sec.   63.7(e)(1)..................  Conduct of Tests;        No........................  Sec.   63.606
                                      startup, shutdown, and                               specifies additional
                                      malfunction provisions.                              requirements.
Sec.   63.7(e)(2) through (4)......  Conduct of Tests.......  Yes.......................  Sec.   63.606
                                                                                           specifies additional
                                                                                           requirements.
Sec.   63.7(f).....................  Alternative Test Method  Yes.......................  None.
Sec.   63.7(g).....................  Data Analysis..........  Yes.......................  None.
Sec.   63.7(h).....................  Waiver of Tests........  Yes.......................  None.
Sec.   63.8(a).....................  Monitoring Requirements  Yes.......................  None.
                                      Applicability.
Sec.   63.8(b).....................  Conduct of Monitoring..  Yes.......................  None.
Sec.   63.8(c)(1)(i)...............  General duty to          No........................  See 63.608(b) for
                                      minimize emissions and                               general duty
                                      CMS operation.                                       requirement.
Sec.   63.8(c)(1)(ii)..............  .......................  Yes.......................  None.
Sec.   63.8(c)(1)(iii).............  Requirement to develop   No........................  None.
                                      SSM Plan for CMS.
Sec.   63.8(c)(2) through (4)......  CMS Operation/           Yes.......................  None.
                                      Maintenance.
Sec.   63.8(c)(5)..................  COMS Operation.........  No........................  Subpart AA does not
                                                                                           require COMS.
Sec.   63.8(c)(6) through (8)......  CMS requirements.......  Yes.......................  None.
Sec.   63.8(d)(1) and (2)..........  Quality Control........  Yes.......................  None.
Sec.   63.8(d)(3)..................  Written procedure for    No........................  See Sec.   63.608 for
                                      CMS.                                                 requirement.
Sec.   63.8(e).....................  CMS Performance          Yes.......................  None.
                                      Evaluation.
Sec.   63.8(f)(1) through (5)......  Alternative Monitoring   Yes.......................  None.
                                      Method.
Sec.   63.8(f)(6)..................  Alternative to RATA      Yes.......................  None.
                                      Test.
Sec.   63.8(g)(1)..................  Data Reduction.........  Yes.......................  None.
Sec.   63.8(g)(2)..................  .......................  Yes.......................  None.
Sec.   63.8(g)(3) through (5)......  .......................  Yes.......................  None.
Sec.   63.9(a).....................  Notification             Yes.......................  None.
                                      Requirements
                                      Applicability.
Sec.   63.9(b).....................  Initial Notifications..  Yes.......................  None.
Sec.   63.9(c).....................  Request for Compliance   Yes.......................  None.
                                      Extension.
Sec.   63.9(d).....................  New Source Notification  Yes.......................  None.
                                      for Special Compliance
                                      Requirements.
Sec.   63.9(e).....................  Notification of          Yes.......................  None.
                                      Performance Test.
Sec.   63.9(f).....................  Notification of VE/      No........................  Subpart AA does not
                                      Opacity Test.                                        include VE/opacity
                                                                                           standards.
Sec.   63.9(g).....................  Additional CMS           Yes.......................  Subpart AA does not
                                      Notifications.                                       require CMS
                                                                                           performance
                                                                                           evaluation, COMS, or
                                                                                           CEMS.
Sec.   63.9(h)(1) through (3)......  Notification of          Yes.......................  None.
                                      Compliance Status.
Sec.   63.9(h)(4)..................  .......................  No........................  [Reserved].
Sec.   63.9(h)(5) and (6)..........  .......................  Yes.......................  None.
Sec.   63.9(i).....................  Adjustment of Deadlines  Yes.......................  None.
Sec.   63.9(j).....................  Change in Previous       Yes.......................  None.
                                      Information.
Sec.   63.10(a)....................  Recordkeeping/Reporting- Yes.......................  None.
                                      Applicability.
Sec.   63.10(b)(1).................  General Recordkeeping    Yes.......................  None.
                                      Requirements.
Sec.   63.10(b)(2)(i)..............  Startup or shutdown      No........................  None.
                                      duration.
Sec.   63.10(b)(2)(ii).............  Malfunction............  No........................  See Sec.   63.607 for
                                                                                           recordkeeping and
                                                                                           reporting
                                                                                           requirement.
Sec.   63.10(b)(2)(iii)............  Maintenance records....  Yes.......................  None.
Sec.   63.10(b)(2)(iv) and (v).....  Startup, shutdown,       No........................  None.
                                      malfunction actions.
Sec.   63.10(b)(2)(vi) through       General Recordkeeping    Yes.......................  None.
 (xiv).                               Requirements.
Sec.   63.10(b)(3).................  General Recordkeeping    Yes.......................  None.
                                      Requirements.
Sec.   63.10(c)(1).................  Additional CMS           Yes.......................  None.
                                      Recordkeeping.
Sec.   63.10(c)(2) through (4).....  .......................  No........................  [Reserved].
Sec.   63.10(c)(5).................  .......................  Yes.......................  None.
Sec.   63.10(c)(6).................  .......................  Yes.......................  None.
Sec.   63.10(c)(7) and (8).........  .......................  Yes.......................  None.
Sec.   63.10(c)(9).................  .......................  No........................  [Reserved].
Sec.   63.10(c)(10) through (13)...  .......................  Yes.......................  None.
Sec.   63.10(c)(14)................  .......................  Yes.......................  None.
Sec.   63.10(c)(15)................  Startup Shutdown         No........................  None.
                                      Malfunction Plan
                                      Provisions.
Sec.   63.10(d)(1).................  General Reporting        Yes.......................  None.
                                      Requirements.
Sec.   63.10(d)(2).................  Performance Test         Yes.......................  None.
                                      Results.
Sec.   63.10(d)(3).................  Opacity or VE            No........................  Subpart AA does not
                                      Observations.                                        include VE/opacity
                                                                                           standards.
Sec.   63.10(d)(4).................  Progress Reports.......  Yes.......................  None.
Sec.   63.10(d)(5).................  Startup, Shutdown, and   No........................  See Sec.   63.607 for
                                      Malfunction Reports.                                 reporting of excess
                                                                                           emissions.

[[Page 50450]]

 
Sec.   63.10(e)(1) and (2).........  Additional CMS Reports.  Yes.......................  None.
Sec.   63.10(e)(3).................  Excess Emissions/CMS     Yes.......................  None.
                                      Performance Reports.
Sec.   63.10(e)(4).................  COMS Data Reports......  No........................  Subpart AA does not
                                                                                           require COMS.
Sec.   63.10(f)....................  Recordkeeping/Reporting  Yes.......................  None.
                                      Waiver.
Sec.   63.11.......................  Control Device and Work  Yes.......................  None.
                                      Practice Requirements.
Sec.   63.12.......................  State Authority and      Yes.......................  None.
                                      Delegations.
Sec.   63.13.......................  Addresses..............  Yes.......................  None.
Sec.   63.14.......................  Incorporation by         Yes.......................  None.
                                      Reference.
Sec.   63.15.......................  Information              Yes.......................  None.
                                      Availability/
                                      Confidentiality.
Sec.   63.16.......................  Performance Track        No........................  Terminated.
                                      Provisions.
----------------------------------------------------------------------------------------------------------------

0
21. Part 63 is amended by revising subpart BB to read as follows:

Subpart BB--National Emission Standards for Hazardous Air 
Pollutants from Phosphate Fertilizers Production Plants

Sec.
63.620 Applicability.
63.621 Definitions.
63.622 Standards and compliance dates.
63.623 [Reserved]
63.624 [Reserved]
63.625 Operating and monitoring requirements.
63.626 Performance tests and compliance provisions.
63.627 Notification, recordkeeping, and reporting requirements.
63.628 General requirements and applicability of general provisions 
of this part.
63.629 Miscellaneous requirements.
63.630 [Reserved]
63.631 Exemption from new source performance standards.
63.632 Implementation and enforcement.
Table 1 to Subpart BB of Part 63--Existing Source Emission Limits
Table 2 to Subpart BB of Part 63--New Source Emission Limits
Table 3 to Subpart BB of Part 63--Monitoring Equipment Operating 
Parameters
Table 4 to Subpart BB of Part 63--Operating Parameters, Operating 
Limits and Data Monitoring, Recordkeeping and Compliance Frequencies
Table 5 to Subpart BB of Part 63--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring Systems (CPMS)
Appendix A to Subpart BB of Part 63--Applicability of General 
Provisions (40 CFR part 63, subpart A) to Subpart BB

Sec.  63.620  Applicability.

    (a) Except as provided in paragraphs (c) and (d) of this section, 
you are subject to the requirements of this subpart if you own or 
operate a phosphate fertilizer production plant that is a major source 
as defined in Sec.  63.2. You must comply with the emission 
limitations, work practice standards, and operating parameter 
requirements specified in this subpart at all times.
    (b) The requirements of this subpart apply to emissions of 
hazardous air pollutants (HAP) emitted from the following affected 
sources at a phosphate fertilizer production plant:
    (1) Each phosphate fertilizer process line (e.g., diammonium and/or 
monoammonium phosphate process line).
    (2) Each granular triple superphosphate process line.
    (3) Each granular triple superphosphate storage building.
    (4) Evaporative cooling tower.
    (c) The requirements of this subpart do not apply to a phosphate 
fertilizer production plant that is an area source as defined in Sec.  
63.2.
    (d) The provisions of this subpart do not apply to research and 
development facilities as defined in Sec.  63.621.

Sec.  63.621  Definitions.

    Terms used in this subpart are defined in Sec.  63.2 of the Clean 
Air Act and in this section as follows:
    Diammonium and/or monoammonium phosphate process line means any 
process line manufacturing granular diammonium and/or monoammonium 
phosphate by reacting ammonia with phosphoric acid that has been 
derived from or manufactured by reacting phosphate rock and acid. A 
diammonium and/or monoammonium phosphate process line includes: 
Reactors, granulators, dryers, coolers, screens, and mills.
    Equivalent P2O5 feed means the quantity of 
phosphorus, expressed as phosphorus pentoxide 
(P2O5), fed to the process.
    Equivalent P2O5 stored means the quantity of 
phosphorus, expressed as phosphorus pentoxide, being cured or stored in 
the affected facility.
    Evaporative cooling tower means an open-water, re-circulating 
device that uses fans or natural draft to draw or force ambient air 
through the device to remove heat from process water by direct contact.
    Exceedance means a departure from an indicator range established 
for monitoring under this subpart, consistent with any averaging period 
specified for averaging the results of the monitoring.
    Existing source depends on the date that construction or 
reconstruction of an affected source commenced. A phosphate fertilizer 
process line (e.g., diammonium and/or monoammonium phosphate process 
line), granular triple superphosphate process line, or granular triple 
superphosphate storage is an existing source if construction or 
reconstruction of the affected source commenced on or before December 
27, 1996.
    Fresh granular triple superphosphate means granular triple 
superphosphate produced within the preceding 72 hours.
    Granular triple superphosphate process line means any process line, 
not including storage buildings, that manufactures granular triple 
superphosphate by reacting phosphate rock with phosphoric acid. A 
granular triple superphosphate process line includes: mixers, curing 
belts (dens), reactors, granulators, dryers, coolers, screens, and 
mills.
    Granular triple superphosphate storage building means any building 
curing or storing fresh granular triple superphosphate. A granular 
triple superphosphate storage building includes: storage or curing 
buildings, conveyors, elevators, screens, and mills.
    New source depends on the date that construction or reconstruction 
of an affected source commences. A phosphate fertilizer process line 
(e.g., diammonium and/or monoammonium

[[Page 50451]]

phosphate process line), granular triple superphosphate process line, 
or granular triple superphosphate storage is a new source if 
construction or reconstruction of the affected source commenced after 
December 27, 1996.
    Phosphate fertilizer process line means any process line that 
manufactures a granular phosphate fertilizer by reacting phosphoric 
acid with ammonia. A phosphate fertilizer process line includes: 
reactors, granulators, dryers, coolers, screens, and mills.
    Phosphate fertilizer production plant means any production plant 
that manufactures a granular phosphate fertilizer by reacting 
phosphoric acid with ammonia.
    Research and development facility means research or laboratory 
operations whose primary purpose is to conduct research and development 
into new processes and products, where the operations are under the 
close supervision of technically trained personnel, and where the 
facility is not engaged in the manufacture of products for commercial 
sale in commerce or other off-site distribution, except in a de minimis 
manner.
    Shutdown commences when feed materials cease to be added to an 
affected source and ends when the affected source is deactivated, 
regardless of whether feed material is present in the affected source.
    Startup commences when any feed material is first introduced into 
an affected source and ends when feed material is fully loaded into the 
affected source.
    Total fluorides means elemental fluorine and all fluoride 
compounds, including the HAP hydrogen fluoride, as measured by 
reference methods specified in 40 CFR part 60, appendix A, Method 13 A 
or B, or by equivalent or alternative methods approved by the 
Administrator pursuant to Sec.  63.7(f).

Sec.  63.622  Standards and compliance dates.

    (a) On and after the dates specified in paragraphs (a)(1) through 
(3) of this section, for each phosphate fertilizer process line (e.g., 
diammonium and/or monoammonium phosphate process line), granular triple 
superphosphate process line, and granular triple superphosphate storage 
building, you must comply with the emission limits as specified in 
paragraphs (a)(1) through (3) of this section. If a process line 
contains more than one emission point, you must sum the emissions from 
all emission points in a process line to determine compliance with the 
specified emission limits.
    (1) For each existing phosphate fertilizer process line (e.g., 
diammonium and/or monoammonium phosphate process line), granular triple 
superphosphate process line, and granular triple superphosphate storage 
building that commenced construction or reconstruction on or before 
December 27, 1996, you must comply with the emission limits specified 
in Table 1 to this subpart beginning on June 10, 2002.
    (2) For each new phosphate fertilizer process line (e.g., 
diammonium and/or monoammonium phosphate process line), granular triple 
superphosphate process line, and granular triple superphosphate storage 
building that commences construction or reconstruction after December 
27, 1996 and on or before August 19, 2015, you must comply with the 
emission limits specified in Table 2 to this subpart beginning on June 
10, 1999 or at startup, whichever is later.
    (3) For each new phosphate fertilizer process line (e.g., 
diammonium and/or monoammonium phosphate process line), granular triple 
superphosphate process line, and granular triple superphosphate storage 
building that commences construction or reconstruction after August 19, 
2015, you must comply with the emission limits specified in Table 2 to 
this subpart immediately upon startup.
    (b) Beginning on June 10, 2002, you must not ship fresh granular 
triple superphosphate from your existing granular triple superphosphate 
storage building that commenced construction or reconstruction on or 
before December 27, 1996. Beginning on June 10, 1999 or at startup, 
whichever is later, you must not ship fresh granular triple 
superphosphate from your new granular triple superphosphate storage 
building that commences construction or reconstruction after December 
27, 1996.
    (c) Beginning on August 19, 2015, you must not introduce into any 
evaporative cooling tower any liquid effluent from any absorber 
installed to control emissions from process equipment.
    (d) Beginning on August 19, 2015, during periods of startup and 
shutdown (as defined in Sec.  63.621), you must comply with the work 
practice specified in this paragraph in lieu of the emission limits 
specified in paragraph (a) of this section. During periods of startup 
and shutdown, you must operate any control device(s) being used at the 
affected source, monitor the operating parameters specified in Table 3 
of this subpart, and comply with the operating limits specified in 
Table 4 of this subpart.

Sec.  63.623  [Reserved]

Sec.  63.624  [Reserved]

Sec.  63.625  Operating and monitoring requirements.

    (a) For each phosphate fertilizer process line (e.g., diammonium 
and/or monoammonium phosphate process line), or granular triple 
superphosphate process line subject to the provisions of this subpart, 
you must comply with the monitoring requirements specified in 
paragraphs (a)(1) and (2) of this section.
    (1) Install, calibrate, maintain, and operate a continuous 
monitoring system (CMS) according to your site-specific monitoring plan 
specified in Sec.  63.628(c). The CMS must have an accuracy of 5 percent over its operating range and must determine and 
permanently record the mass flow of phosphorus-bearing material fed to 
the process.
    (2) Maintain a daily record of equivalent 
P2O5 feed. Calculate the equivalent 
P2O5 feed by determining the total mass rate in 
metric ton/hour of phosphorus bearing feed using the procedures 
specified in Sec.  63.626(f)(3).
    (b) For each granular triple superphosphate storage building 
subject to the provisions of this subpart, you must maintain an 
accurate record of the mass of granular triple superphosphate in 
storage to permit the determination of the amount of equivalent 
P2O5 stored.
    (c) For each granular triple superphosphate storage building 
subject to the provisions of this subpart, you must comply with the 
requirements specified in paragraphs (c)(1) and (2) of this section.
    (1) Maintain a daily record of total equivalent 
P2O5 stored by multiplying the percentage 
P2O5 content, as determined by Sec.  
63.626(f)(3)(ii), by the total mass of granular triple superphosphate 
stored as specified in paragraph (b) of this section.
    (2) Develop for approval by the Administrator a site-specific 
methodology including sufficient recordkeeping for the purposes of 
demonstrating compliance with Sec.  63.622(b).
    (d) If you use a control device(s) to comply with the emission 
limits specified in Table 1 or 2 of this subpart, you must install a 
continuous parameter monitoring system (CPMS) and comply with the 
requirements specified in paragraphs (d)(1) through (4) of this 
section.
    (1) You must monitor the operating parameter(s) applicable to the 
control device that you use as specified in Table 3 to this subpart and 
establish the applicable limit or range for the operating parameter 
limit as specified in

[[Page 50452]]

paragraphs (d)(1)(i) and (ii) of this section, as applicable.
    (i) Except as specified in paragraph (d)(1)(ii) of this section, 
determine the value(s) as the arithmetic average of operating parameter 
measurements recorded during the three test runs conducted for the most 
recent performance test.
    (ii) If you use an absorber to comply with the emission limits in 
Table 1 or 2 to this subpart and you monitor pressure drop across the 
absorber, you must establish allowable ranges using the methodology 
specified in paragraphs (d)(1)(ii)(A) and (B) of this section.
    (A) The allowable range for the daily averages of the pressure drop 
across each absorber is 20 percent of the baseline average 
value determined in paragraph (d)(1)(i) of this section. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (B) As an alternative to paragraph (d)(1)(ii)(A) of this section, 
you may establish allowable ranges for the daily averages of the 
pressure drop across an absorber for the purpose of assuring compliance 
with this subpart using the procedures described in this paragraph. You 
must establish the allowable ranges based on the baseline average 
values recorded during previous performance tests or the results of 
performance tests conducted specifically for the purposes of this 
paragraph. You must conduct all performance tests using the methods 
specified in Sec.  63.626. You must certify that the control devices 
and processes have not been modified since the date of the performance 
test from which you obtained the data used to establish the allowable 
ranges. When a source using the methodology of this paragraph is 
retested, you must determine new allowable ranges of baseline average 
values unless the retest indicates no change in the operating 
parameters outside the previously established ranges.
    (2) You must monitor, record, and demonstrate continuous compliance 
using the minimum frequencies specified in Table 4 to this subpart.
    (3) You must comply with the calibration and quality control 
requirements that are applicable to the operating parameter(s) you 
monitor as specified in Table 5 to this subpart.
    (4) If you use a fabric filter system to comply with the emission 
limits specified in Table 1 or 2 to this subpart, the system must meet 
the requirements for fabric filters specified in paragraph (e) of this 
section.
    (e) Beginning August 19, 2016, if you use a fabric filter system to 
comply with the emission limits specified in Table 1 or 2 to this 
subpart, then the fabric filter must be equipped with a bag leak 
detection system that is installed, calibrated, maintained and 
continuously operated according to the requirements in paragraphs 
(e)(1) through (10) of this section.
    (1) Install a bag leak detection sensor(s) in a position(s) that 
will be representative of the relative or absolute particulate matter 
loadings for each exhaust stack, roof vent, or compartment (e.g., for a 
positive-pressure fabric filter) of the fabric filter.
    (2) Use a bag leak detection system certified by the manufacturer 
to be capable of detecting particulate matter emissions at 
concentrations of 1 milligram per actual cubic meter (0.00044 grains 
per actual cubic feet) or less.
    (3) Use a bag leak detection system equipped with a device to 
continuously record the output signal from the system sensor.
    (4) Use a bag leak detection system equipped with a system that 
will trigger an alarm when an increase in relative particulate material 
emissions over a preset level is detected. The alarm must be located 
such that the alert is observed readily by plant operating personnel.
    (5) Install a bag leak detection system in each compartment or cell 
for positive-pressure fabric filter systems that do not duct all 
compartments or cells to a common stack. Install a bag leak detector 
downstream of the fabric filter if a negative-pressure or induced-air 
filter is used. If multiple bag leak detectors are required, the 
system's instrumentation and alarm may be shared among detectors.
    (6) Calibration of the bag leak detection system must, at a 
minimum, consist of establishing the baseline output level by adjusting 
the range and the averaging period of the device and establishing the 
alarm set points and the alarm delay time.
    (7) After initial adjustment, you must not adjust the sensitivity 
or range, averaging period, alarm set points or alarm delay time, 
except as established in your site-specific monitoring plan required in 
Sec.  63.628(c). In no event may the sensitivity be increased more than 
100 percent or decreased by more than 50 percent over a 365-day period 
unless such adjustment follows a complete inspection of the fabric 
filter system that demonstrates that the system is in good operating 
condition.
    (8) Operate and maintain each fabric filter and bag leak detection 
system such that the alarm does not sound more than 5 percent of the 
operating time during a 6-month period. If the alarm sounds more than 5 
percent of the operating time during a 6-month period, it is considered 
an operating parameter exceedance. Calculate the alarm time (i.e., time 
that the alarm sounds) as specified in paragraphs (e)(8)(i) through 
(iii) of this section.
    (i) If inspection of the fabric filter demonstrates that corrective 
action is not required, the alarm duration is not counted in the alarm 
time calculation.
    (ii) If corrective action is required, each alarm time is counted 
as a minimum of 1 hour.
    (iii) If it takes longer than 1 hour to initiate corrective action, 
each alarm time (i.e., time that the alarm sounds) is counted as the 
actual amount of time taken by you to initiate corrective action.
    (9) If the alarm on a bag leak detection system is triggered, you 
must initiate procedures within 1 hour of an alarm to identify the 
cause of the alarm and then initiate corrective action, as specified in 
Sec.  63.628(d)(2), no later than 48 hours after an alarm. Failure to 
take these actions within the prescribed time periods is considered a 
violation.
    (10) Retain records of any bag leak detection system alarm, 
including the date, time, duration, and the percent of the total 
operating time during each 6-month period that the alarm triggers, with 
a brief explanation of the cause of the alarm, the corrective action 
taken, and the schedule and duration of the corrective action.

Sec.  63.626  Performance tests and compliance provisions.

    (a) You must conduct an initial performance test to demonstrate 
compliance with the emission limits specified in Tables 1 and 2 to this 
subpart, within 180 days of the applicable compliance date specified in 
Sec.  63.622.
    (b) After you conduct the initial performance test specified in 
paragraph (a) of this section, you must conduct a performance test once 
per calendar year.
    (c) For affected sources (as defined in Sec.  63.620) that have not 
operated since the previous annual performance test was conducted and 
more than 1 year has passed since the previous performance test, you 
must conduct a performance test no later than 180 days after the re-
start of the affected source

[[Page 50453]]

according to the applicable provisions in Sec.  63.7(a)(2).
    (d)(1) You must conduct the performance tests specified in this 
section at representative (normal) conditions for the process. 
Representative (normal) conditions means those conditions that:
    (i) Represent the range of combined process and control measure 
conditions under which the facility expects to operate (regardless of 
the frequency of the conditions); and
    (ii) Are likely to most challenge the emissions control measures of 
the facility with regard to meeting the applicable emission standards, 
but without creating an unsafe condition.
    (2) Operations during startup, shutdown, and malfunction do not 
constitute representative (normal) operating conditions for purposes of 
conducting a performance test. You must record the process information 
that is necessary to document the operating conditions during the test 
and include in such record an explanation to support that such 
conditions represent representative (normal) conditions. Upon request, 
you must make available to the Administrator such records as may be 
necessary to determine the conditions of performance tests.
    (e) In conducting all performance tests, you must use as reference 
methods and procedures the test methods in 40 CFR part 60, appendix A, 
or other methods and procedures as specified in this section, except as 
provided in Sec.  63.7(f).
    (f) For each phosphate fertilizer process line (e.g., diammonium 
and/or monoammonium phosphate process line), and granular triple 
superphosphate process line, you must determine compliance with the 
applicable total fluorides standards specified in Tables 1 and 2 to 
this subpart as specified in paragraphs (f)(1) through (3) of this 
section.
    (1) Compute the emission rate (E) of total fluorides for each run 
using Equation BB-1:
[GRAPHIC] [TIFF OMITTED] TR19AU15.003

Where:

E = Emission rate of total fluorides, gram/metric ton (pound/ton) of 
equivalent P2O5 feed.
Ci = Concentration of total fluorides from emission point ``i,'' 
milligram/dry standard cubic meter (milligram/dry standard cubic 
feet).
Qi = Volumetric flow rate of effluent gas from emission point ``i,'' 
dry standard cubic meter/hour (dry standard cubic feet/hour).
N = Number of emission points associated with the affected facility.
P = Equivalent P2O5 feed rate, metric ton/hour 
(ton/hour).
K = Conversion factor, 1000 milligram/gram (453,600 milligram/
pound).

    (2) You must use Method 13A or 13B (40 CFR part 60, appendix A) to 
determine the total fluorides concentration (Ci) and the 
volumetric flow rate (Qi) of the effluent gas at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. The sampling volume for each run at each 
emission point must be at least 0.85 dscm (30 dscf). If Method 13B is 
used, the fusion of the filtered material described in Section 7.3.1.2 
and the distillation of suitable aliquots of containers 1 and 2, 
described in section 7.3.3 and 7.3.4 in Method 13 A, may be omitted.
    (3) Compute the equivalent P2O5 feed rate (P) 
using Equation BB-2:
[GRAPHIC] [TIFF OMITTED] TR19AU15.004

Where:

P = P2O5 feed rate, metric ton/hour (ton/
hour).
Mp = Total mass flow rate of phosphorus-bearing feed, 
metric ton/hour (ton/hour).
Rp = P2O5 content, decimal 
fraction.

    (i) Determine the mass flow rate (Mp) of the phosphorus-
bearing feed using the measurement system described in Sec.  63.625(a).
    (ii) Determine the P2O5 content 
(Rp) of the feed using, as appropriate, the following 
methods specified in the Book of Methods Used and Adopted By The 
Association of Florida Phosphate Chemists (incorporated by reference, 
see Sec.  63.14) where applicable:
    (A) Section IX, Methods of Analysis for Phosphate Rock, No. 1 
Preparation of Sample.
    (B) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method A--Volumetric 
Method.
    (C) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method B--Gravimetric 
Quimociac Method.
    (D) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method C--Spectrophotometric Method.
    (E) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A--Volumetric 
Method.
    (F) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B--Gravimetric 
Quimociac Method.
    (G) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method C--
Spectrophotometric Method.
    (g) For each granular triple superphosphate storage building, you 
must determine compliance with the applicable total fluorides standards 
specified in Tables 1 and 2 to this subpart as specified in paragraphs 
(g)(1) through (7) of this section.
    (1) You must conduct performance tests only when the following 
quantities of product are being cured or stored in the facility:
    (i) Total granular triple superphosphate is at least 10 percent of 
the building capacity, and
    (ii) Fresh granular triple superphosphate is at least six percent 
of the total amount of granular triple superphosphate, or
    (iii) If the provision in paragraph (g)(1)(ii) of this section 
exceeds production capabilities for fresh granular triple 
superphosphate, the fresh granular triple superphosphate is equal to at 
least 5 days maximum production.
    (2) Compute the emission rate (E) of total fluorides for each run 
using Equation BB-3:

[[Page 50454]]

[GRAPHIC] [TIFF OMITTED] TR19AU15.005

Where:

E = Emission rate of total fluorides, gram/hour/metric ton (pound/
hour/ton) of equivalent P2O5 stored.
Ci = Concentration of total fluorides from emission point 
``i'', milligram/dry standard cubic meter (milligram/dry standard 
cubic feet).
Qi = Volumetric flow rate of effluent gas from emission 
point ``i'', dry standard cubic meter/hour (dry standard cubic feet/
hour).
N = Number of emission points in the affected facility.
P = Equivalent P2O5 stored, metric tons 
(tons).
K = Conversion factor, 1000 milligram/gram (453,600 milligram/
pound).

    (3) You must use Method 13A or 13B (40 CFR part 60, appendix A) to 
determine the total fluorides concentration (Ci) and the 
volumetric flow rate (Qi) of the effluent gas at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. The sampling volume for each run at each 
emission point must be at least 0.85 dscm (30 dscf). If Method 13B is 
used, the fusion of the filtered material described in Section 7.3.1.2 
and the distillation of suitable aliquots of containers 1 and 2, 
described in section 7.3.3 and 7.3.4 in Method 13A, may be omitted.
    (4) Compute the equivalent P2O5 stored (P) 
using Equation BB-4:
[GRAPHIC] [TIFF OMITTED] TR19AU15.006

Where:

P = P2O5 stored (ton).
Mp = Amount of product in storage, metric ton (ton).
Rp = P2O5 content of product in 
storage, weight fraction.

    (5) Determine the amount of product (Mp) in storage 
using the measurement system described in Sec.  63.625(b) and (c).
    (6) Determine the P2O5 content 
(Rp) of the product stored using, as appropriate, the 
following methods specified in the Book of Methods Used and Adopted By 
The Association of Florida Phosphate Chemists (incorporated by 
reference, see Sec.  63.14) where applicable:
    (i) Section XI, Methods of Analysis For Phosphoric Acid, 
Superphosphate, Triple superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A--Volumetric 
Method.
    (ii) Section XI, Methods of Analysis For Phosphoric Acid, 
Superphosphate, Triple superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B--Gravimetric 
Quimociac Method.
    (iii) Section XI, Methods of Analysis For Phosphoric Acid, 
Superphosphate, Triple superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method C--
Spectrophotometric Method, or,
    (7) Determine the P2O5 content 
(Rp) of the product stored using, as appropriate, the 
following methods specified in the Official Methods of Analysis of AOAC 
International (incorporated by reference, see Sec.  63.14) where 
applicable:
    (i) AOAC Official Method 957.02 Phosphorus (Total) In Fertilizers, 
Preparation of Sample Solution.
    (ii) AOAC Official Method 929.01 Sampling of Solid Fertilizers.
    (iii) AOAC Official Method 929.02 Preparation of Fertilizer Sample.
    (iv) AOAC Official Method 978.01 Phosphorus (Total) in Fertilizers, 
Automated Method.
    (v) AOAC Official Method 969.02 Phosphorus (Total) in Fertilizers, 
Alkalimetric Quinolinium Molybdophosphate Method.
    (vi) AOAC Official Method 962.02 Phosphorus (Total) in Fertilizers, 
Gravimetric Quinolinium Molybdophosphate Method.
    (vii) AOAC Official Method 958.01 Phosphorus (Total) in 
Fertilizers, Spectrophotometric Molybdovanadophosphate Method.
    (h) If you use a CMS, you must conduct a performance evaluation, as 
specified in Sec.  63.8(e), in accordance with your site-specific 
monitoring plan in Sec.  63.628(c). For fabric filters, you must 
conduct a performance evaluation of the bag leak detection system 
consistent with the guidance provided in Office Of Air Quality Planning 
And Standards (OAQPS), Fabric Filter Bag Leak Detection Guidance 
(incorporated by reference, see Sec.  63.14). You must record the 
sensitivity of the bag leak detection system to detecting changes in 
particulate matter emissions, range, averaging period, and alarm set 
points during the performance test.

Sec.  63.627  Notification, recordkeeping, and reporting requirements.

    (a) You must comply with the notification requirements specified in 
Sec.  63.9. During the most recent performance test, if you demonstrate 
compliance with the emission limit while operating your control device 
outside the previously established operating limit, you must establish 
a new operating limit based on that most recent performance test and 
notify the Administrator that the operating limit changed based on data 
collected during the most recent performance test. When a source is 
retested and the performance test results are submitted to the 
Administrator pursuant to paragraph (b)(1) of this section, Sec.  
63.7(g)(1), or Sec.  63.10(d)(2), you must indicate whether the 
operating limit is based on the new performance test or the previously 
established limit. Upon establishment of a new operating limit, you 
must thereafter operate under the new operating limit. If the 
Administrator determines that you did not conduct the compliance test 
in accordance with the applicable requirements or that the operating 
limit established during the performance test does not correspond to 
representative (normal) conditions, you must conduct a new performance 
test and establish a new operating limit.
    (b) You must comply with the reporting and recordkeeping 
requirements in Sec.  63.10 as specified in paragraphs (b)(1) through 
(5) of this section.
    (1) You must comply with the general recordkeeping requirements in 
Sec.  63.10(b)(1); and
    (2) As required by Sec.  63.10(d), you must report the results of 
the initial and subsequent performance tests as part of the 
notification of compliance status required in Sec.  63.9(h). You must 
verify in the performance test reports that the operating limits for 
each process have not changed or provide documentation of revised 
operating limits established according to Sec.  63.625, as applicable. 
In the notification of compliance status, you must also:
    (i) Certify to the Administrator that you have not shipped fresh 
granular triple superphosphate from an affected facility.

[[Page 50455]]

    (ii) Certify to the Administrator annually that you have complied 
with the evaporative cooling tower requirements specified in Sec.  
63.622(c).
    (iii) Submit analyses and supporting documentation demonstrating 
conformance with the Office Of Air Quality Planning And Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance (incorporated by 
reference, see Sec.  63.14) and specifications for bag leak detection 
systems as part of the notification of compliance status report.
    (iv) If you elect to demonstrate compliance by following the 
procedures in Sec.  63.625(d)(1)(ii)(B), certify to the Administrator 
annually that the control devices and processes have not been modified 
since the date of the performance test from which you obtained the data 
used to establish the allowable ranges.
    (3) As required by Sec.  63.10(e)(1), you must submit an excess 
emissions report for any exceedance of an emission or operating 
parameter limit if the total duration of the exceedances for the 
reporting period is 1 percent of the total operating time for the 
reporting period or greater. The report must contain the information 
specified in Sec.  63.10 and paragraph (b)(4) of this section. When 
exceedances of an emission limit or operating parameter have not 
occurred, you must include such information in the report. You must 
submit the report semiannually and the report must be delivered or 
postmarked by the 30th day following the end of the calendar half. If 
exceedances are reported, you must submit the excess emissions report 
quarterly until a request to reduce reporting frequency is approved as 
described in Sec.  63.10(e)(3).
    (4) In the event that an affected unit fails to meet an applicable 
standard, record and report the following information for each failure:
    (i) The date, time and duration of the failure.
    (ii) A list of the affected sources or equipment for which a 
failure occurred.
    (iii) An estimate of the volume of each regulated pollutant emitted 
over any emission limit.
    (iv) A description of the method used to estimate the emissions.
    (v) A record of actions taken to minimize emissions in accordance 
with Sec.  63.628(b), and any corrective actions taken to return the 
affected unit to its normal or usual manner of operation.
    (5) You must submit a summary report containing the information 
specified in Sec.  63.10(e)(3)(vi). You must submit the summary report 
semiannually and the report must be delivered or postmarked by the 30th 
day following the end of the calendar half.
    (c) Your records must be in a form suitable and readily available 
for expeditious review. You must keep each record for 5 years following 
the date of each recorded action. You must keep each record on site, or 
accessible from a central location by computer or other means that 
instantly provide access at the site, for at least 2 years after the 
date of each recorded action. You may keep the records off site for the 
remaining 3 years.
    (d) In computing averages to determine compliance with this 
subpart, you must exclude the monitoring data specified in paragraphs 
(d)(1) through (3) of this section.
    (1) Periods of non-operation of the process unit;
    (2) Periods of no flow to a control device; and
    (3) Any monitoring data recorded during continuous parameter 
monitoring system (CPMS) breakdowns, out-of-control periods, repairs, 
maintenance periods, instrument adjustments or checks to maintain 
precision and accuracy, calibration checks, and zero (low-level), mid-
level (if applicable), and high-level adjustments.
    (e) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2) required by this subpart, you must 
submit the results of the performance tests, including any associated 
fuel analyses, following the procedure specified in either paragraph 
(e)(1) or (2) of this section.
    (1) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(http://www.epa.gov/ttn/chief/ert/index.html), you must submit the 
results of the performance test to the EPA via the Compliance and 
Emissions Data Reporting Interface (CEDRI). CEDRI can be accessed 
through the EPA's Central Data Exchange (CDX) (http://cdx.epa.gov/epa_home.asp). Performance test data must be submitted in a file format 
generated through the use of the EPA's ERT. Alternatively, you may 
submit performance test data in an electronic file format consistent 
with the extensible markup language (XML) schema listed on the EPA's 
ERT Web site once the XML schema is available. If you claim that some 
of the performance test information being submitted is confidential 
business information (CBI), you must submit a complete file generated 
through the use of the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT Web site, 
including information claimed to be CBI, on a compact disc, flash 
drive, or other commonly used electronic storage media to the EPA. The 
electronic media must be clearly marked as CBI and mailed to U.S. EPA/
OAPQS/CORE CBI Office, Attention: Group Leader, Measurement Policy 
Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same ERT or 
alternate file with the CBI omitted must be submitted to the EPA via 
the EPA's CDX as described earlier in this paragraph.
    (2) For data collected using test methods that are not supported by 
the EPA's ERT as listed on the EPA's ERT Web site, you must submit the 
results of the performance test to the Administrator at the appropriate 
address listed in Sec.  63.13.

Sec.  63.628  General requirements and applicability of general 
provisions of this part.

    (a) You must comply with the general provisions in subpart A of 
this part as specified in appendix A to this subpart.
    (b) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. The general duty 
to minimize emissions does not require you to make any further efforts 
to reduce emissions if levels required by this standard have been 
achieved. Determination by the Administrator of whether a source is 
operating in compliance with operation and maintenance requirements 
will be based on information available to the Administrator that may 
include, but is not limited to, monitoring results, review of operation 
and maintenance procedures, review of operation and maintenance 
records, and inspection of the source.
    (c) For each CMS used to demonstrate compliance with any applicable 
emission limit, you must develop, and submit to the Administrator for 
approval upon request, a site-specific monitoring plan according to the 
requirements specified in paragraphs (c)(1) through (3) of this 
section. You must submit the site-specific monitoring plan, if 
requested by the Administrator, at least 60 days before the initial 
performance evaluation of the CMS. The requirements of this paragraph 
also apply if a petition is made to the Administrator for alternative 
monitoring parameters under Sec.  63.8(f).
    (1) You must include the information specified in paragraphs 
(c)(1)(i) through (vi) of this section in the site-specific monitoring 
plan.

[[Page 50456]]

    (i) Location of the CMS sampling probe or other interface. You must 
include a justification demonstrating that the sampling probe or other 
interface is at a measurement location relative to each affected 
process unit such that the measurement is representative of control of 
the exhaust emissions (e.g., on or downstream of the last control 
device).
    (ii) Performance and equipment specifications for the sample 
interface, the pollutant concentration or parametric signal analyzer, 
and the data collection and reduction systems.
    (iii) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations).
    (iv) Ongoing operation and maintenance procedures in accordance 
with the general requirements of Sec.  63.8(c)(1)(ii), (c)(3), 
(c)(4)(ii), and Table 4 to this subpart.
    (v) Ongoing data quality assurance procedures in accordance with 
the general requirements of Sec.  63.8(d)(1) and (2) and Table 5 to 
this subpart.
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c), (e)(1), (e)(2)(i).
    (2) You must include a schedule for conducting initial and 
subsequent performance evaluations in the site-specific monitoring 
plan.
    (3) You must keep the site-specific monitoring plan on site for the 
life of the affected source or until the affected source is no longer 
subject to the provisions of this part, to be made available for 
inspection, upon request, by the Administrator. If you revise the site-
specific monitoring plan, you must keep previous (i.e., superseded) 
versions of the plan on site to be made available for inspection, upon 
request, by the Administrator, for a period of 5 years after each 
revision to the plan. You must include the program of corrective action 
required under Sec.  63.8(d)(2) in the plan.
    (d) For each bag leak detection system installed to comply with the 
requirements specified in Sec.  63.625(e), you must include the 
information specified in paragraphs (d)(1) and (2) of this section in 
the site-specific monitoring plan specified in paragraph (c) of this 
section.
    (1) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations), including how the alarm set-point will be 
established.
    (2) A corrective action plan describing corrective actions to be 
taken and the timing of those actions when the bag leak detection alarm 
sounds. Corrective actions may include, but are not limited to, the 
actions specified in paragraphs (d)(2)(i) through (vi) of this section.
    (i) Inspecting the fabric filter for air leaks, torn or broken bags 
or filter media, or any other conditions that may cause an increase in 
regulated material emissions.
    (ii) Sealing off defective bags or filter media.
    (iii) Replacing defective bags or filter media or otherwise 
repairing the control device.
    (iv) Sealing off a defective fabric filter compartment.
    (v) Cleaning the bag leak detection system probe or otherwise 
repairing the bag leak detection system.
    (vi) Shutting down the process controlled by the fabric filter.

Sec.  63.629  Miscellaneous requirements.

    The Administrator retains the authority to approve site-specific 
test plans for uncontrolled granular triple superphosphate storage 
buildings developed pursuant to Sec.  63.7(c)(2)(i).

Sec.  63.630  [Reserved]

Sec.  63.631  Exemption from new source performance standards.

    Any affected source subject to the provisions of this subpart is 
exempted from any otherwise applicable new source performance standard 
contained in 40 CFR part 60, subpart V, subpart W, or subpart X. To be 
exempt, a source must have a current operating permit pursuant to title 
V of the Clean Air Act and the source must be in compliance with all 
requirements of this subpart. For each affected source, this exemption 
is effective upon the date that you demonstrate to the Administrator 
that the requirements of Sec. Sec.  63.625 and 63.626 have been met.

Sec.  63.632  Implementation and enforcement.

    (a) This subpart is implemented and enforced by the U.S. EPA, or a 
delegated authority such as the applicable state, local, or Tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
state, local, or Tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out if 
implementation and enforcement of this subpart is delegated to a state, 
local, or Tribal agency.
    (b) The authorities specified in paragraphs (b)(1) through (5) of 
this section are retained by the Administrator of U.S. EPA and cannot 
be delegated to State, local, or Tribal agencies.
    (1) Approval of alternatives to the requirements in Sec. Sec.  
63.620, 63.622, 63.625, 63.629, and 63.631.
    (2) Approval of requests under Sec. Sec.  63.7(e)(2)(ii) and 63.7 
(f) for alternative requirements or major changes to the test methods 
specified in this subpart, as defined in Sec.  63.90.
    (3) Approval of requests under Sec.  63.8(f) for alternative 
requirements or major changes to the monitoring requirements specified 
in this subpart, as defined in Sec.  63.90.
    (4) Waiver or approval of requests under Sec.  63.10(f) for 
alternative requirements or major changes to the recordkeeping and 
reporting requirements specified in this subpart, as defined in Sec.  
63.90.
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

  Table 1 to Subpart BB of Part 63--Existing Source Emission Limits a b
------------------------------------------------------------------------
                                             You must meet the emission
                                              limits for the specified
 For the following existing sources . . .          pollutant . . .
                                           -----------------------------
                                                   Total fluorides
------------------------------------------------------------------------
Phosphate Fertilizer Process Line (e.g.,    0.060 lb/ton of equivalent
 Diammonium and/or Monoammonium Phosphate    P2O5 feed.
 Process Line).
Granular Triple Superphosphate Process      0.150 lb/ton of equivalent
 Line.                                       P2O5 feed.
GTSP storage building.....................  5.0 x 10-4 lb/hr/ton of
                                             equivalent P2O5 stored.
------------------------------------------------------------------------
\a\ The existing source compliance date is June 10, 2002.
\b\ During periods of startup and shutdown, for emission limits stated
  in terms of pounds of pollutant per ton of feed, you are subject to
  the work practice standards specified in Sec.   63.622(d).

[[Page 50457]]

    Table 2 to Subpart BB of Part 63--New Source Emission Limits a b
------------------------------------------------------------------------
                                             You must meet the emission
                                              limits for the specified
    For the following new sources . . .            pollutant . . .
                                           -----------------------------
                                                   Total fluorides
------------------------------------------------------------------------
Phosphate Fertilizer Process Line (e.g.,    0.0580 lb/ton of equivalent
 Diammonium and/or Monoammonium Phosphate    P2O5 feed.
 Process Line).
Granular Triple Superphosphate Process      0.1230 lb/ton of equivalent
 Line.                                       P2O5 feed.
GTSP storage building.....................  5.0 x 10-4 lb/hr/ton of
                                             equivalent P2O5 stored.
------------------------------------------------------------------------
\a\ The new source compliance dates are based on date of construction or
  reconstruction as specified in Sec.   63.622(a).
\b\ During periods of startup and shutdown, for emission limits stated
  in terms of pounds of pollutant per ton of feed, you are subject to
  the work practice standards specified in Sec.   63.622(d).

                   Table 3 to Subpart BB of Part 63--Monitoring Equipment Operating Parameters
----------------------------------------------------------------------------------------------------------------
                                                                 And you must monitor .
            You must . . .                     If . . .                   . .                   And . . .
----------------------------------------------------------------------------------------------------------------
                                            Absorbers (Wet Scrubbers)
----------------------------------------------------------------------------------------------------------------
Install a continuous parameter         Your absorber is         Influent liquid flow.
 monitoring system (CPMS) for liquid    designed and operated
 flow at the inlet of the absorber..    with pressure drops of
                                        5 inches of water
                                        column or more; and
                                        you choose to monitor
                                        only the influent
                                        liquid flow, rather
                                        than the liquid-to-gas
                                        ratio.
Install CPMS for liquid and gas flow   Your absorber is         Liquid-to-gas ratio as   You must measure the
 at the inlet of the absorber.          designed and operated    determined by dividing   gas stream by:
                                        with pressure drops of   the influent liquid     Measuring the gas
                                        5 inches of water        flow rate by the inlet   stream flow at the
                                        column or less; or.      gas flow rate. The       absorber inlet; or
                                       Your absorber is          units of measure must   Using the design blower
                                        designed and operated    be consistent with       capacity, with
                                        with pressure drops of   those used to            appropriate
                                        5 inches of water        calculate this ratio     adjustments for
                                        column or more, and      during the performance   pressure drop.
                                        you choose to monitor    test.
                                        the liquid-to-gas
                                        ratio, rather than
                                        only the influent
                                        liquid flow, and you
                                        want the ability to
                                        lower liquid flow with
                                        changes in gas flow.
Install CPMS for pressure at the gas   Your absorber is         Pressure drop through    You may measure the
 stream inlet and outlet of the         designed and operated    the absorber.            pressure of the inlet
 absorber.                              with pressure drops of                            gas using amperage on
                                        5 inches of water                                 the blower if a
                                        column or more.                                   correlation between
                                                                                          pressure and amperage
                                                                                          is established.
----------------------------------------------------------------------------------------------------------------

 Table 4 to Subpart BB of Part 63--Operating Parameters, Operating Limits and Data Monitoring, Recordkeeping and
                                             Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                    You must        And you must
                                  establish the   monitor, record,
  For the operating parameter       following      and demonstrate                                         Data
     applicable to you, as       operating limit     continuous     Data measurement   Data recording    averaging
  specified in Table 3 . . .       during your    compliance using                                      period for
                                performance test    these minimum                                       compliance
                                      . . .          frequencies
------------------------------------------------------------------------------------------------------ ------------
                                       Absorbers (Wet Scrubbers)
----------------------------------------------------------------------------------------------------------------
Influent liquid flow..........  Minimum inlet     Continuous......  Every 15 minutes  Daily.
                                 liquid flow.
Influent liquid flow rate and   Minimum influent  Continuous......  Every 15 minutes  Daily.
 gas stream flow rate.           liquid-to-gas
                                 ratio.
Pressure drop.................  Pressure drop     Continuous......  Every 15 minutes  Daily.
                                 range.
----------------------------------------------------------------------------------------------------------------

[[Page 50458]]

    Table 5 to Subpart BB of Part 63--Calibration and Quality Control
     Requirements for Continuous Parameter Monitoring Systems (CPMS)
------------------------------------------------------------------------
                                                    And your calibration
     If you monitor this          Your accuracy     requirements are . .
       parameter . . .        requirements are . .            .
                                        .
------------------------------------------------------------------------
Flow Rate...................   5        Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               flow measured or      period of more than
                               1.9 liters per        24 hours throughout
                               minute (0.5 gallons   which the flow rate
                               per minute),          exceeded the
                               whichever is          maximum rated flow
                               greater, for liquid   rate of the sensor,
                               flow rate..           or the data
                               5         recorder was off
                               percent over the      scale. Checks of
                               normal range of       all mechanical
                               flow measured or 28   connections for
                               liters per minute     leakage monthly.
                               (10 cubic feet per    Visual inspections
                               minute), whichever    and checks of CPMS
                               is greater, for gas   operation every 3
                               flow rate..           months, unless the
                               5         CPMS has a
                               percent over the      redundant flow
                               normal range          sensor.
                               measured for mass    Selection of a
                               flow rate..           representative
                                                     measurement
                                                     location where
                                                     swirling flow or
                                                     abnormal velocity
                                                     distributions due
                                                     to upstream and
                                                     downstream
                                                     disturbances at the
                                                     point of
                                                     measurement are
                                                     minimized.
Pressure....................   5        Checks for
                               percent over the      obstructions (e.g.,
                               normal range          pressure tap
                               measured or 0.12      pluggage) at least
                               kilopascals (0.5      once each process
                               inches of water       operating day.
                               column), whichever   Performance
                               is greater..          evaluation annually
                                                     and following any
                                                     period of more than
                                                     24 hours throughout
                                                     which the pressure
                                                     exceeded the
                                                     maximum rated
                                                     pressure of the
                                                     sensor, or the data
                                                     recorder was off
                                                     scale.
                                                    Checks of all
                                                     mechanical
                                                     connections for
                                                     leakage monthly.
                                                    Visual inspection of
                                                     all components for
                                                     integrity,
                                                     oxidation and
                                                     galvanic corrosion
                                                     every 3 months,
                                                     unless the CPMS has
                                                     a redundant
                                                     pressure sensor.
                                                    Selection of a
                                                     representative
                                                     measurement
                                                     location that
                                                     minimizes or
                                                     eliminates
                                                     pulsating pressure,
                                                     vibration, and
                                                     internal and
                                                     external corrosion.
------------------------------------------------------------------------

Appendix A to Subpart BB of Part 63--Applicability of General 
Provisions (40 CFR Part 63, Subpart A) to Subpart BB

----------------------------------------------------------------------------------------------------------------
           40 CFR citation                   Requirement         Applies to subpart BB           Comment
----------------------------------------------------------------------------------------------------------------
Sec.   63.1(a)(1) through (4)........  General Applicability..  Yes....................  None.
Sec.   63.1(a)(5)....................  .......................  No.....................  [Reserved].
Sec.   63.1(a)(6)....................  Contact information....  Yes....................  None.
Sec.   63.1(a)(7) through (9)........  .......................  No.....................  [Reserved].
Sec.   63.1(a)(10) through (12)......  Time periods...........  Yes....................  None.
Sec.   63.1(b).......................  Initial Applicability    Yes....................  None.
                                        Determination.
Sec.   63.1(c)(1)....................  Applicability After      Yes....................  None.
                                        Standard Established.
Sec.   63.1(c)(2)....................  Permits................  Yes....................  Some plants may be area
                                                                                          sources.
Sec.   63.1(c)(3) through (4)........  .......................  No.....................  [Reserved].
Sec.   63.1(c)(5)....................  Area to Major source     Yes....................  None.
                                        change.
Sec.   63.1(d).......................  .......................  No.....................  [Reserved].
Sec.   63.1(e).......................  Applicability of Permit  Yes....................  None.
                                        Program.
Sec.   63.2..........................  Definitions............  Yes....................  Additional definitions
                                                                                          in Sec.   63.621.
Sec.   63.3..........................  Units and Abbreviations  Yes....................  None.
Sec.   63.4(a)(1) and (2)............  Prohibited Activities..  Yes....................  None.
Sec.   63.4(a)(3) through (5)........  .......................  No.....................  [Reserved].
Sec.   63.4(b) and (c)...............  Circumvention/           Yes....................  None.
                                        Fragmentation.
Sec.   63.5(a).......................  Construction/            Yes....................  None.
                                        Reconstruction
                                        Applicability.
Sec.   63.5(b)(1)....................  Existing, New,           Yes....................  None.
                                        Reconstructed Sources
                                        Requirements.
Sec.   63.5(b)(2)....................  .......................  No.....................  [Reserved].
Sec.   63.5(b)(3), (4), and (6)......  Construction/            Yes....................  None.
                                        Reconstruction
                                        approval and
                                        notification.
Sec.   63.5(b)(5)....................  .......................  No.....................  [Reserved].
Sec.   63.5(c).......................  .......................  No.....................  [Reserved].
Sec.   63.5(d).......................  Application for          Yes....................  None.
                                        Approval of
                                        Construction/
                                        Reconstruction.
Sec.   63.5(e).......................  Approval of              Yes....................  None.
                                        Construction/
                                        Reconstruction.
Sec.   63.5(f).......................  Approval of              Yes....................  None.
                                        Construction/
                                        Reconstruction Based
                                        on State Review.
Sec.   63.6(a).......................  Compliance with          Yes....................  None.
                                        Standards and
                                        Maintenance
                                        Applicability.

[[Page 50459]]

 
Sec.   63.6(b)(1) through (5)........  New and Reconstructed    Yes....................  See also Sec.   63.622.
                                        Sources Dates.
Sec.   63.6(b)(6)....................  .......................  No.....................  [Reserved].
Sec.   63.6(b)(7)....................  Area to major source     Yes....................  None.
                                        change.
Sec.   63.6(c)(1) and (2)............  Existing Sources Dates.  Yes....................  Sec.   63.622 specifies
                                                                                          dates.
Sec.   63.6(c)(3) and (4)............  .......................  No.....................  [Reserved].
Sec.   63.6(c)(5)....................  Area to major source     Yes....................  None.
                                        change.
Sec.   63.6(d).......................  .......................  No.....................  [Reserved].
Sec.   63.6(e)(1)(i) and (ii)........  Operation & Maintenance  No.....................  See Sec.   63.628(b)
                                        Requirements.                                     for general duty
                                                                                          requirement.
Sec.   63.6(e)(iii)..................  .......................  Yes....................  None.
Sec.   63.6(e)(2)....................  .......................  No.....................  [Reserved].
Sec.   63.6(e)(3)....................  Startup, Shutdown, and   No.....................  None.
                                        Malfunction Plan.
Sec.   63.6(f).......................  Compliance with          No.....................  See general duty at
                                        Emission Standards.                               Sec.   63.628(b).
Sec.   63.6(g).......................  Alternative Standard...  Yes....................  None.
Sec.   63.6(h).......................  Compliance with Opacity/ No.....................  Subpart BB does not
                                        VE Standards.                                     include VE/opacity
                                                                                          standards.
Sec.   63.6(i)(1) through (14).......  Extension of Compliance  Yes....................  None.
Sec.   63.6(i)(15)...................  .......................  No.....................  [Reserved].
Sec.   63.6(i)(16)...................  .......................  Yes....................  None.
Sec.   63.6(j).......................  Exemption from           Yes....................  None.
                                        Compliance.
Sec.   63.7(a).......................  Performance Test         Yes....................  None.
                                        Requirements
                                        Applicability.
Sec.   63.7(b).......................  Notification...........  Yes....................  None.
Sec.   63.7(c).......................  Quality Assurance/Test   Yes....................  None.
                                        Plan.
Sec.   63.7(d).......................  Testing Facilities.....  Yes....................  None.
Sec.   63.7(e)(1)....................  Conduct of Tests;        No.....................  Sec.   63.626 specifies
                                        startup, shutdown and                             additional
                                        malfunction provisions.                           requirements.
Sec.   63.7(e)(2) through (4)........  Conduct of Tests.......  Yes....................  Sec.   63.626 specifies
                                                                                          additional
                                                                                          requirements.
Sec.   63.7(f).......................  Alternative Test Method  Yes....................  None.
Sec.   63.7(g).......................  Data Analysis..........  Yes....................  None.
Sec.   63.7(h).......................  Waiver of Tests........  Yes....................  None.
Sec.   63.8(a).......................  Monitoring Requirements  Yes....................  None.
                                        Applicability.
Sec.   63.8(b).......................  Conduct of Monitoring..  Yes....................  None.
Sec.   63.8(c)(1)(i).................  General duty to          No.....................  See Sec.   63.628(b)
                                        minimize emissions and                            for general duty
                                        CMS operation.                                    requirement.
Sec.   63.8(c)(1)(ii)................  .......................  Yes....................  None.
Sec.   63.8(c)(1)(iii)...............  Requirement to develop   No.....................  None.
                                        SSM Plan for CMS.
Sec.   63.8(c)(2) through (4)........  CMS Operation/           Yes....................  None.
                                        Maintenance.
Sec.   63.8(c)(5)....................  COMS Operation.........  No.....................  Subpart BB does not
                                                                                          require COMS.
Sec.   63.8(c)(6) through (8)........  CMS requirements.......  Yes....................  None.
Sec.   63.8(d)(1) and (2)............  Quality Control........  Yes....................  None.
Sec.   63.8(d)(3)....................  Written procedure for    No.....................  See Sec.   63.628 for
                                        CMS.                                              requirement.
Sec.   63.8(e).......................  CMS Performance          Yes....................  None.
                                        Evaluation.
Sec.   63.8(f)(1) through (5)........  Alternative Monitoring   Yes....................  None.
                                        Method.
Sec.   63.8(f)(6)....................  Alternative to RATA      No.....................  Subpart BB does not
                                        Test.                                             require CEMS.
Sec.   63.8(g)(1)....................  Data Reduction.........  Yes....................  None.
Sec.   63.8(g)(2)....................  .......................  No.....................  Subpart BB does not
                                                                                          require COMS or CEMS.
Sec.   63.8(g)(3) through (5)........  .......................  Yes....................  None.
Sec.   63.9(a).......................  Notification             Yes....................  None.
                                        Requirements
                                        Applicability.
Sec.   63.9(b).......................  Initial Notifications..  Yes....................  None.
Sec.   63.9(c).......................  Request for Compliance   Yes....................  None.
                                        Extension.
Sec.   63.9(d).......................  New Source Notification  Yes....................  None.
                                        for Special Compliance
                                        Requirements.
Sec.   63.9(e).......................  Notification of          Yes....................  None.
                                        Performance Test.
Sec.   63.9(f).......................  Notification of VE/      No.....................  Subpart BB does not
                                        Opacity Test.                                     include VE/opacity
                                                                                          standards.
Sec.   63.9(g).......................  Additional CMS           Yes....................  None.
                                        Notifications.
Sec.   63.9(h)(1) through (3)........  Notification of          Yes....................  None.
                                        Compliance Status.
Sec.   63.9(h)(4)....................  .......................  No.....................  [Reserved].
Sec.   63.9(h)(5) and (6)............  .......................  Yes....................  None.
Sec.   63.9(i).......................  Adjustment of Deadlines  Yes....................  None.
Sec.   63.9(j).......................  Change in Previous       Yes....................  None.
                                        Information.
Sec.   63.10(a)......................  Recordkeeping/Reporting- Yes....................  None.
                                        Applicability.
Sec.   63.10(b)(1)...................  General Recordkeeping    Yes....................  None.
                                        Requirements.
Sec.   63.10(b)(2)(i)................  Startup or shutdown      No.....................  None.
                                        duration.

[[Page 50460]]

 
Sec.   63.10(b)(2)(ii)...............  Malfunction............  No.....................  See Sec.   63.627 for
                                                                                          recordkeeping and
                                                                                          reporting requirement.
Sec.   63.10(b)(2)(iii)..............  Maintenance records....  Yes....................  None.
Sec.   63.10(b)(2)(iv) and (v).......  Startup, shutdown,       No.....................  None.
                                        malfunction actions.
Sec.   63.10(b)(2)(vi) through (xiv).  General Recordkeeping    Yes....................  None.
                                        Requirements.
Sec.   63.10(b)(3)...................  General Recordkeeping    Yes....................  None.
                                        Requirements.
Sec.   63.10(c)(1)...................  Additional CMS           Yes....................  None.
                                        Recordkeeping.
Sec.   63.10(c)(2) through (4).......  .......................  No.....................  [Reserved].
Sec.   63.10(c)(5)...................  .......................  Yes....................  None.
Sec.   63.10(c)(6)...................  .......................  Yes....................  None.
Sec.   63.10(c)(7) and (8)...........  .......................  Yes....................  None.
Sec.   63.10(c)(9)...................  .......................  No.....................  [Reserved].
Sec.   63.10(c)(10) through (13).....  .......................  Yes....................  None.
Sec.   63.10(c)(14)..................  .......................  Yes....................  None.
Sec.   63.10(c)(15)..................  Startup Shutdown         No.....................  None.
                                        Malfunction Plan
                                        Provisions.
Sec.   63.10(d)(1)...................  General Reporting        Yes....................  None.
                                        Requirements.
Sec.   63.10(d)(2)...................  Performance Test         Yes....................  None.
                                        Results.
Sec.   63.10(d)(3)...................  Opacity or VE            No.....................  Subpart BB does not
                                        Observations.                                     include VE/opacity
                                                                                          standards.
Sec.   63.10(d)(4)...................  Progress Reports.......  Yes....................  None.
Sec.   63.10(d)(5)...................  Startup, Shutdown, and   No.....................  See Sec.   63.627 for
                                        Malfunction Reports.                              reporting of excess
                                                                                          emissions.
Sec.   63.10(e)(1) and (2)...........  Additional CMS Reports.  Yes....................  None.
Sec.   63.10(e)(3)...................  Excess Emissions/CMS     Yes....................  None.
                                        Performance Reports.
Sec.   63.10(e)(4)...................  COMS Data Reports......  No.....................  Subpart BB does not
                                                                                          require COMS.
Sec.   63.10(f)......................  Recordkeeping/Reporting  Yes....................  None.
                                        Waiver.
Sec.   63.11.........................  Control Device and Work  Yes....................  None.
                                        Practice Requirements.
Sec.   63.12.........................  State Authority and      Yes....................  None.
                                        Delegations.
Sec.   63.13.........................  Addresses..............  Yes....................  None.
Sec.   63.14.........................  Incorporation by         Yes....................  None.
                                        Reference.
Sec.   63.15.........................  Information              Yes....................  None.
                                        Availability/
                                        Confidentiality.
Sec.   63.16.........................  Performance Track        No.....................  Terminated.
                                        Provisions.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2015-19732 Filed 8-18-15; 8:45 am]
 BILLING CODE 6560-50-P