[Federal Register Volume 81, Number 167 (Monday, August 29, 2016)]
[Rules and Regulations]
[Pages 59275-59330]
[FR Doc No: 2016-17700]

Vol. 81

Monday,

No. 167

August 29, 2016

Part II

 Environmental Protection Agency

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40 CFR Part 60

Emission Guidelines and Compliance Times for Municipal Solid Waste
Landfills; Final Rule

Federal Register / Vol. 81 , No. 167 / Monday, August 29, 2016 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2014-0451; FRL-9949-55-OAR]
RIN 2060-AS23

Emission Guidelines and Compliance Times for Municipal Solid
Waste Landfills

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing a new
subpart that updates the Emission Guidelines and Compliance Times for
Municipal Solid Waste Landfills (Emission Guidelines). The EPA reviewed
the landfills Emission Guidelines based on changes in the landfills
industry since the Emission Guidelines were promulgated in 1996. The
EPA's review of the Emission Guidelines for municipal solid waste (MSW)
landfills considered landfills that accepted waste after November 8,
1987, and commenced construction, reconstruction, or modification on or
before July 17, 2014. Based on this review, the EPA has determined that
it is appropriate to revise the Emission Guidelines to reflect changes
to the population of landfills and the results of an analysis of the
timing and methods for reducing emissions. This action will achieve
additional reductions in emissions of landfill gas and its components,
including methane, by lowering the emissions threshold at which a
landfill must install controls. This action also incorporates new data
and information received in response to an advanced notice of proposed
rulemaking and a proposed rulemaking and addresses other regulatory
issues including surface emissions monitoring, wellhead monitoring, and
the definition of landfill gas treatment system.
    The revised Emission Guidelines, once implemented through revised
state plans or a revised federal plan, will reduce emissions of
landfill gas, which contains both nonmethane organic compounds and
methane. Landfills are a significant source of methane, which is a
potent greenhouse gas pollutant. These avoided emissions will improve
air quality and reduce the potential for public health and welfare
effects associated with exposure to landfill gas emissions.

DATES: This final rule is effective on October 28, 2016.
    The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 28, 2016.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2014-0451. All documents in the docket are
listed in the http://www.regulations.gov index. Although listed in the
index, some information is not publicly available, e.g., 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 electronically through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: For information concerning this final
rule, contact Ms. Hillary Ward, Fuels and Incineration Group, Sector
Policies and Programs Division, Office of Air Quality Planning and
Standards (E143-05), Environmental Protection Agency, Research Triangle
Park, NC 27711; telephone number:<PHONE_NUMBER>; fax number: (919)
541-0246; email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Acronyms and Abbreviations. The following acronyms and
abbreviations are used in this document.

ANPRM Advance notice of proposed rulemaking
ANSI American National Standards Institute
BMP Best management practice
Btu British thermal unit
CAA Clean Air Act
CBI Confidential business information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CO2 Carbon dioxide
CO2e Carbon dioxide equivalent
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
FID Flame ionization detector
GCCS Gas collection and control system
GHG Greenhouse gas
GHGRP Greenhouse Gas Reporting Program
GWP Global warming potential
HAP Hazardous air pollutant
HOV Higher operating value
IAMS Integrated assessment models
ICR Information collection request
IPCC Intergovernmental Panel on Climate Change
IWG Interagency working group
LFG Landfill gas
LFGCost Landfill Gas Energy Cost Model
m\3\ Cubic meters
Mg Megagram
Mg/yr Megagram per year
mph Miles per hour
MSW Municipal solid waste
mtCO2e Metric tons of carbon dioxide equivalent
MW Megawatt
MWh Megawatt hour
NAICS North American Industry Classification System
NESHAP National Emission Standards for Hazardous Air Pollutants
NMOC Nonmethane organic compound
NRC National Research Council
NSPS New source performance standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PM Particulate matter
PM2.5 Fine particulate matter
ppm Parts per million
ppmvd Parts per million by dry volume
RCRA Resource Conservation and Recovery Act
RD&D Research, development, and demonstration
RFA Regulatory Flexibility Act
SBAR Small Business Advocacy Review
SC-CH4 Social cost of methane
SC-CO2 Social cost of carbon dioxide
SEM Surface emissions monitoring
SO2 Sulfur dioxide
SSM Startup, shutdown, and malfunction
Tg Teragram
TIP Tribal implementation plan
TTN Technology Transfer Network
U.S. United States
USGCRP U.S. Global Change Research Program
VCS Voluntary consensus standard
VOC Volatile organic compound
    Organization of This Document. The following outline is provided to
aid in locating information in this preamble.

I. Executive Summary
    A. Purpose of Regulatory Action
    B. Summary of Major Provisions
    C. Costs and Benefits
II. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related
information?
III. Background
    A. Landfill Gas Emissions and Climate Change
    B. What are the public health and welfare effects of landfill
gas emissions?
    C. What is the EPA's authority for reviewing the Emission
Guidelines?
    D. What is the purpose and scope of this action?
    E. How would the changes in applicability affect sources
currently subject to subparts Cc and WWW?
IV. Summary of the Final Emission Guidelines
    A. What are the control requirements?
    B. What are the monitoring, recordkeeping, and reporting
requirements?
    C. Startup, Shutdown, and Malfunction Provisions
V. Summary of Significant Changes Since Proposal
    A. Changes to Monitoring, Recordkeeping, and Reporting
    B. Tier 4
    C. Changes to Address Closed or Non-Productive Areas
    D. Startup, Shutdown, and Malfunction Provisions

    E. Other Corrections and Clarifications
VI. Rationale for Significant Changes Since Proposal
    A. Changes to Monitoring, Recordkeeping, and Reporting
    B. Tier 4
    C. Changes to Address Closed or Non-Productive Areas
    D. Startup, Shutdown, and Malfunction Provisions
    E. Other Corrections and Clarifications
VII. Impacts of This Final Rule
    A. What are the air quality impacts?
    B. What are the water quality and solid waste impacts?
    C. What are the secondary air impacts?
    D. What are the energy impacts?
    E. What are the cost impacts?
    F. What are the economic impacts?
    G. What are the benefits?
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (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 that 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 (CRA)

I. Executive Summary

A. Purpose of Regulatory Action

    This action finalizes changes to the MSW landfills Emission
Guidelines resulting from the EPA's review of the Emission Guidelines
under Clean Air Act (CAA) section 111. The EPA's review identified a
number of advances in technology and operating practices for reducing
emissions of landfill gas (LFG) and the final changes are based on our
evaluation of those advances and our understanding of LFG emissions.
The resulting changes to the Emission Guidelines will achieve
additional reductions in emissions of LFG and its components, including
methane. This final rule is consistent with the President's 2013
Climate Action Plan,\1\ which directs federal agencies to focus on
``assessing current emissions data, addressing data gaps, identifying
technologies and best practices for reducing emissions, and identifying
existing authorities and incentive-based opportunities to reduce
methane emissions.'' The final rule is also consistent with the
President's Methane Strategy,\2\ which directs the EPA's regulatory and
voluntary programs to continue to pursue emission reductions through
regulatory updates and to encourage LFG energy recovery through
voluntary programs. These directives are discussed in detail in section
III.A of this preamble. This regulatory action also resolves or
clarifies several implementation issues that were previously addressed
in amendments proposed on May 23, 2002 (67 FR 36475) and September 8,
2006 (71 FR 53271).
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    \1\ Executive Office of the President, ``The President's Climate
Action Plan'' June 2013. https://www.whitehouse.gov/sites/default/files/image/president27sclimateactionplan.pdf.
    \2\ Executive Office of the President, ``Climate Action Plan
Strategy to Reduce Methane, March 2014. https://www.whitehouse.gov/sites/default/files/strategy_to_reduce_methane_emissions_2014-03-28_final.pdf.
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1. Need for Regulatory Action
    The EPA reviewed the Emission Guidelines to determine the potential
for achieving additional reductions in emissions of LFG. Significant
changes have occurred in the landfill industry over time, including
changes to the size and number of existing landfills, industry
practices, and gas control methods and technologies. Based on the EPA's
review, we are finalizing changes to the Emission Guidelines. The
changes will achieve additional emission reductions of LFG and its
components (including methane), which will reduce air pollution and the
resulting harm to public health and welfare. Landfills are a
significant source of methane, a potent greenhouse gas, for which there
are cost-effective means of reduction, so this rule is an important
element of the United States' work to reduce emissions that are
contributing to climate change. In addition, the changes provide more
effective options for demonstrating compliance, and provide
clarification of several implementation issues raised during the
amendments proposed in 2002 and 2006. Additional information supporting
the EPA's decision to review the Emission Guidelines can be found in
Section I.A. of the Emission Guidelines proposal (80 FR 52100, August
27, 2015).
2. Legal Authority
    The EPA is not statutorily obligated to conduct a review of the
Emission Guidelines, but has the discretion to do so when circumstances
indicate that it is appropriate. The EPA determined that it was
appropriate to review the Emission Guidelines based on changes in the
landfill industry and changes in operation of landfills, including the
size, trends in gas collection and control system installations, and
age of landfills since the Emission Guidelines were promulgated in
1996. The EPA compiled new information on landfills through data
collection efforts for a statutorily mandated review of the existing
new source performance standards (NSPS) (40 CFR part 60, subpart WWW),
public comments received on the NSPS proposal (79 FR 41796, July 17,
2014), public comments received on the Advance Notice of Proposed
Rulemaking (ANPRM) (79 FR 41772, July 17, 2014), and public comments
received on the Emission Guidelines proposal (80 FR 52100, August 27,
2015) for use in reviewing the Emission Guidelines. This information
allowed the EPA to assess current practices, emissions, and the
potential for additional emission reductions.
    The EPA interprets CAA section 111(d) as providing discretionary
authority to update emission guidelines, and by extension to require
states to update standards of performance, in appropriate
circumstances. The EPA believes this is the best, and perhaps only,
permissible interpretation of the CAA. It is consistent with the gap
filling nature of section 111(d), the general purposes of the CAA to
protect and enhance air quality. Moreover, this is supported because
Congress's grant of authority to issue regulations carries with it the
authority to amend or update regulations \3\ that they have issued.\4\
``Regulatory agencies do not establish rules of conduct to last
forever; they are supposed, within the limits of the law and of fair
and prudent administration, to adapt their rules and practices to the
Nation's needs in a volatile, changing economy. They are neither
required nor supposed to regulate the present and the future within the
inflexible limits of yesterday.'' \5\
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    \3\ Congress has provided the Agency with broad authority to
issue regulations ``as necessary to carry out [her] functions
under'' the Act. This broad grant of authority further supports the
reasonableness of EPA's interpretation.
    \4\ See Trujillo v. General Electric Co., 621 F.2d 1084, 1086
(10th Cir. 1980) (``Administrative agencies have an inherent
authority to reconsider their own decisions, since the power to
decide in the first instance carries with it the power to
reconsider.'') (citing Albertson v. FCC, 182 F.2d 397, 399 (D.C.
Cir. 1950)). See 621 F.2d at 1088 (``The authority to reconsider may
result in some instances, as it did here, in a totally new and
different determination.'').
    \5\ American Trucking Ass'n v. Atchison, Topeka & Santa Fe Ry.,
387 U.S. 397, 416 (1967).
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    To interpret the CAA otherwise would mean that Congress intended to

allow existing sources to operate forever without any consideration of
the need for updated controls simply because, at some point in the
distant past, the EPA had previously required these sources to be
regulated. The EPA's interpretation is consistent with the gap filling
nature of section 111(d), whereas the opposite interpretation would
undermine it. By its terms, section 111(d) was designed to address
emissions from existing sources of non-national ambient air quality
standards (NAAQS), non-CAA section 112 hazardous air pollutants.\6\ A
one-off approach would mean that the EPA would be unable to address the
threats from these sources even as we improve our understanding of the
danger presented by the pollutant at issue or new or improved control
options become available. Indeed, this lack of authority would exist
even in cases such as the instant one where some affected sources had
not yet been required to invest in emission controls.
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    \6\ CAA subsection 111(d)(1)(A)(i), provides that regulation
under CAA section 111(d) is intended to cover pollutants that are
not regulated under either the criteria pollutant/NAAQS provisions
or section 112 of the CAA. Thus, section 111(d) is designed to
regulate pollutants from existing sources that fall in the gap not
covered by the criteria pollutant provisions or the hazardous air
pollutant provisions. This gap-filling purpose can be seen in the
early legislative history of the CAA. As originally enacted in the
1970 CAA, the precursor to CAA section 111 (which was originally
section 114) was described as covering pollutants that would not be
controlled by the criteria pollutant provisions or the hazardous air
pollutant provisions. See S. Committee Rep. to accompany S. 4358
(Sept. 17, 1970), 1970 CAA Legis. Hist. at 420 (``It should be noted
that the emission standards for pollutants which cannot be
considered hazardous (as defined in section 115 [which later became
section 112]) could be established under section 114 [later, section
111]. Thus, there should be no gaps in control activities pertaining
to stationary source emissions that pose any significant danger to
public health or welfare.''); Statement by S. Muskie, S. Debate on
S. 4358 (Sept. 21, 1970), 1970 CAA Legis. Hist. at 227 (``[T]he bill
[in section 114] provides the Secretary with the authority to set
emission standards for selected pollutants which cannot be
controlled through the ambient air quality standards and which are
not hazardous substances.'').
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    The overall structure of the CAA also supports EPA's
interpretation. The primary goal of the CAA is: ``[T]o protect and
enhance the Nation's air resources so as to promote the public health
and welfare and the productive capacity of its population.'' CAA
section 101(b)(1), 42 U.S.C. 7401(b)(1). The CAA goes about this in a
number of ways. Under section 111 the chosen approach is through the
identification of the best system of emission reduction available to
reduce emissions to the atmosphere which takes into account the cost of
achieving such reductions and any nonair quality health and
environmental impact and energy requirements. These systems change over
time. Where such changes have the effect of substantially reducing
harmful air emissions, it would be illogical that the EPA would be
precluded from requiring existing sources to update their controls in
recognition of those changes, particularly when those sources may
continue to operate for decades. Similarly, if, after a rule was
finalized, factual information were to arise revealing that the initial
standards were too stringent to be met, it would be illogical that EPA
would be precluded from revising the standards accordingly. Had
Congress intended to preclude the EPA from updating the emission
guidelines to reflect changes, it would surely have specifically said
so, something it did not do.
    The fact that the EPA has the authority to update the emission
guidelines does not, however, mean that it is unconstrained in
exercising that authority. Rather, the decision whether to update a
particular set of emission guidelines must be made on a rule-specific
basis after considering the same factors the EPA considered in
establishing those guidelines, including the level of reductions
achievable and the cost of achieving those reductions, and, as
appropriate, taking into account controls sources installed to comply
with the initial emission guidelines. The EPA has determined that it is
appropriate to update the emission guidelines for municipal solid waste
(MSW) landfills. The EPA's final rule is not a requirement to install
new and different control equipment (compared to the existing rule),
but rather to install the same basic controls, i.e., a well-designed
and well-operated landfill gas collection and control system, on an
accelerated basis. While this will result in some additional cost, the
EPA believes that cost is fully justified given the substantial
reduction in emissions of landfill gas and its constituent components,
including methane, that will result. As indicated in the final rule,
lowering the threshold above which landfill owners/operators must
install a gas collection and control system from 50 Mg of non-methane
organic compounds (NMOC) per year to 34 Mg/year will result in an
additional reduction in NMOC emissions of 1,810 Mg/yr and a concomitant
reduction in methane emissions of 0.285 million Mg/yr. In these
circumstances, the EPA believes that it not only has the legal
authority to update the emission guidelines, but that doing so
imminently reasonable.

B. Summary of Major Provisions

    The final Emission Guidelines apply to landfills that accepted
waste after November 8, 1987,\7\ and that commenced construction,
reconstruction, or modification on or before July 17, 2014 (the date of
publication of proposed revisions to the landfills NSPS, 40 CFR part
60, subpart XXX). The final rule provisions are described below.
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    \7\ This date in 1987 is the date on which permit programs were
established under the Hazardous and Solid Waste Amendments of the
Resource, Conservation and Recovery Act (RCRA) which amended the
Solid Waste Disposal Act (SWDA), 42 U.S.C. 6901-6992k. This date was
also selected as the regulatory cutoff in the Emission Guidelines
for landfills no longer receiving wastes because the EPA judged
states would be able to identify active facilities as of this date.
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    Thresholds for Installing Controls. The final Emission Guidelines
retain the current design capacity thresholds of 2.5 million megagrams
(Mg) and 2.5 million cubic meters (m\3\), but reduce the nonmethane
organic compounds (NMOC) emission threshold for the installation and
removal of a gas collection and control system (GCCS) from 50 Mg/yr to
34 Mg/yr for landfills that are not closed as of September 27, 2017. (A
megagram is also known as a metric ton, which is equal to 1.1 U.S.
short tons or about 2,205 pounds.) An MSW landfill that exceeds the
design capacity thresholds must install and start up a GCCS within 30
months after LFG emissions reach or exceed an NMOC level of 34 Mg/yr.
Consistent with the existing Emission Guidelines, the owner or operator
of a landfill may control the gas by routing it to a non-enclosed
flare, an enclosed combustion device, or a treatment system that
processes the collected gas for subsequent sale or beneficial use.
    Emission Threshold Determination. The EPA is finalizing an
alternative site-specific emission threshold determination methodology
for when a landfill must install and operate a GCCS. This alternative
methodology, referred to as ``Tier 4,'' is based on surface emissions
monitoring (SEM) and demonstrates whether or not surface emissions are
below a specific threshold. The Tier 4 SEM demonstration allows
landfills that exceed the threshold using modeled NMOC emission rates
using Tier 1 or 2 to demonstrate that actual site-specific surface
methane emissions are below a specific threshold. A landfill that can
demonstrate that surface emissions are below 500 parts per million
(ppm) for four consecutive quarters does not trigger the requirement to
install a GCCS even if Tier 1, 2, or 3 calculations

indicate that the 34 Mg/yr threshold has been exceeded. Landfills that
have calculated NMOC emissions of 50 Mg/yr or greater are not eligible
for the Tier 4 emission threshold determination in order to prevent
conflicting requirements between subpart Cf and the landfills NESHAP
(40 CFR part 63, subpart AAAA). Many landfills that are subject to
subpart Cf will also be subject to the landfills NESHAP. The landfills
NESHAP requires landfills that exceed the size threshold (2.5 million
Mg and 2.5 million m\3\) and exceed the NMOC emissions threshold (50
Mg/yr) to install and operate a GCCS.
    Closed Landfill Subcategory. Because closed landfills do not
produce as much LFG as an active landfill, the EPA is finalizing a
separate subcategory for landfills that close on or before September
27, 2017. Landfills in this subcategory will continue to be subject to
an NMOC emission threshold of 50 Mg/yr for determining when controls
must be installed or can be removed.
    Low LFG Producing Areas. The EPA is also finalizing criteria for
determining when it is appropriate to cap or remove all or a portion of
the GCCS. The final criteria for capping or removing all or a portion
of the GCCS are: (1) The landfill is closed, (2) the GCCS has operated
for at least 15 years or the landfill owner or operator can demonstrate
that the GCCS will be unable to operate for 15 years due to declining
gas flows, and (3) the calculated NMOC emission rate at the landfill is
less than 34 Mg/yr on three successive test dates. The final rule does
not contain a GCCS removal criterion based on surface emissions
monitoring.
    Landfill Gas Treatment. In the final Emission Guidelines, the EPA
has addressed two issues related to LFG treatment. First, the EPA is
clarifying that the use of treated LFG is not limited to use as a fuel
for a stationary combustion device but may be used for other beneficial
uses such as vehicle fuel, production of high-British thermal unit
(Btu) gas for pipeline injection, or use as a raw material in a
chemical manufacturing process. Second, the EPA is finalizing a
definition of treated landfill gas that applies to LFG processed in a
treatment system meeting the requirements in 40 CFR part 60, subpart
Cf, and defining treatment system as a system that filters, de-waters,
and compresses LFG for sale or beneficial use. The definition of
treatment system allows the level of treatment to be tailored to the
type and design of the specific combustion equipment or the other
beneficial use such as vehicle fuel, production of high-Btu gas for
pipeline injection, or use as a raw material in a chemical
manufacturing process in which the LFG is used. Owners or operators
must develop a site-specific treatment system monitoring plan that
includes monitoring parameters addressing all three elements of
treatment (filtration, de-watering, and compression) to ensure the
treatment system is operating properly for the intended end use of the
treated LFG. They also must keep records that demonstrate that such
parameters effectively monitor filtration, de-watering, and compression
system performance necessary for the end use of the treated LFG.
    Wellhead Operational Standards. The EPA is finalizing changes to
certain operational standards (i.e., the requirement to meet specific
operating limits) for nitrogen/oxygen level at the wellheads. Landfill
owners or operators are not required to take corrective action based on
exceedances of specified operational standards for nitrogen/oxygen
levels at wellheads, but they must continue to monitor and maintain
records of nitrogen/oxygen levels on a monthly basis in order to inform
any necessary adjustments to the GCCS and must maintain records of
monthly readings. The operational standard, corrective action, and
corresponding recordkeeping and reporting remain for temperature and
maintaining negative pressure at the wellhead.
    Surface Monitoring. The EPA is finalizing a requirement to monitor
all surface penetrations at existing landfills. In final 40 CFR part
60, subpart Cf, landfills must conduct SEM at all cover penetrations
and openings within the area of the landfill where waste has been
placed and a gas collection system is required to be in place and
operating according to the operational standards in final 40 CFR part
60, subpart Cf. Specifically, landfill owners or operators must conduct
surface monitoring on a quarterly basis at the specified intervals and
where visual observations indicate elevated concentrations of LFG, such
as distressed vegetation and cracks or seeps in the cover and all cover
penetrations.
    Startup, Shutdown, and Malfunction. The EPA is finalizing a
requirement that standards of performance in the Emission Guidelines
apply at all times, including periods of startup, shutdown, and
malfunction (SSM). The EPA is also finalizing an alternative standard
during SSM events: In the event the collection or control system is not
operating, the gas mover system must be shut down and all valves in the
collection and control system contributing to venting of the gas to the
atmosphere must be closed within 1 hour of the collection or control
system not operating.
    Other Clarifications. The EPA is finalizing a number of
clarifications to address several issues that have been raised by
landfill owners or operators during implementation of the current NSPS
and Emission Guidelines. These clarifications include adding criteria
for when an affected source must update its design plan and clarifying
when landfill owners or operators must submit requests to extend the
timeline for taking corrective action. The EPA is also updating several
definitions in the Emission Guidelines. In addition, while the EPA is
not mandating organics diversion, we are finalizing two specific
compliance flexibilities in the Emission Guidelines to encourage wider
adoption of organics diversion and GCCS best management practices
(BMPs) for emission reductions at landfills. These compliance
flexibilities are discussed in section V.A.1 and VI.A.1 (wellhead
monitoring) and section V.B and section VI.B (Tier 4 emission threshold
determination) of this preamble.

C. Costs and Benefits

    The final Emission Guidelines are expected to significantly reduce
emissions of LFG and its components, which include methane, volatile
organic compounds (VOC), and hazardous air pollutants (HAP). Landfills
are a significant source of methane emissions, and in 2014, landfills
represented the third largest source of human-related methane emissions
in the U.S. This rulemaking applies to existing landfills that
commenced construction, modification, or reconstruction on or before
July 17, 2014 and accepted waste after 1987. The EPA estimates 1,851
existing landfills that accepted waste after 1987 and opened prior to
2014.
    To comply with the emission limits in the final rule, MSW landfill
owners or operators are expected to install the least-cost control for
collecting, and treating or combusting LFG. The annualized net cost for
the final Emission Guidelines is estimated to be $54.1 million (2012$)
in 2025, when using a 7 percent discount rate. The annualized costs
represent the costs compared to no changes to the current Emission
Guidelines (i.e., baseline) and include $92.6 million to install and
operate a GCCS, as well as $0.76 million to complete the corresponding
testing and monitoring. These control costs are offset by $39.3 million
in revenue from electricity sales, which is incorporated into the net
control costs for certain landfills that are expected to generate
revenue by using the LFG to produce electricity.

    Installation of a GCCS to comply with the 34 Mg/yr NMOC emissions
threshold at open landfills would achieve reductions of 1,810 Mg/yr
NMOC and 285,000 metric tons methane (about 7.1 million metric tons of
carbon dioxide equivalent (mtCO2e)) beyond the baseline in
year 2025. In addition, the final rule is expected to result in the net
reduction of an additional 277,000 Mg CO2, due to reduced
demand for electricity from the grid as landfills generate electricity
from LFG. The NMOC portion of LFG can contain a variety of air
pollutants, including VOC and various organic HAP. VOC emissions are
precursors to both fine particulate matter (PM2.5) and ozone
formation. These pollutants, along with methane, are associated with
substantial health effects, welfare effects, and climate effects. The
EPA expects that the reduced emissions will result in improvements in
air quality and lessen the potential for health effects associated with
exposure to air pollution related emissions, and result in climate
benefits due to reductions of the methane component of LFG.
    The EPA estimates that the final rule's estimated methane emission
reductions and secondary CO2 emission reductions in the year
2025 would yield global monetized climate benefits of $200 million to
approximately $1.2 billion, depending on the discount rate. Using the
average social cost of methane (SC-CH4) and the average
social cost of CO2 (SC-CO2), each at a 3-percent
discount rate, results in an estimate of about $440 million in 2025
(2012$).
    The SC-CH4 and SC-CO2 are the monetary values
of impacts associated with marginal changes in methane and
CO2 emissions, respectively, in a given year. It includes a
wide range of anticipated climate impacts, such as net changes in
agricultural productivity, property damage from increased flood risk,
and changes in energy system costs, such as reduced costs for heating
and increased costs for air conditioning.
    With the data available, we are not able to provide health benefit
estimates for the reduction in exposure to HAP, ozone, and
PM2.5 for this rule. This is not to imply that there are no
such benefits of the rule; rather, it is a reflection of the
difficulties in modeling the direct and indirect impacts of the
reductions in emissions for this sector with the data currently
available.
    Based on the monetized benefits and costs, the annual net benefits
of the final guidelines are estimated to be $390 million ($2012) in
2025, based on the average SC-CH4 at a 3 percent discount
rate, average SC-CO2 at a 3 percent discount rate, and costs
at a 7 percent discount rate.

II. General Information

A. Does this action apply to me?

    This final rule addresses existing MSW landfills, i.e., landfills
accepting waste after 1987 and on which construction was commenced on
or before July 17, 2014, and associated solid waste management
programs. Potentially affected categories include those listed in Table
1 of this preamble.

                       Table 1--Regulated Entities
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                                                    Examples of affected
             Category                   NAICS a          facilities
------------------------------------------------------------------------
Industry: Air and water resource            924110  Solid waste
 and solid waste management.                         landfills.
Industry: Refuse systems--solid             562212  Solid waste
 waste landfills.                                    landfills.
State, local, and tribal                    924110  Administration of
 government agencies.                                air and water
                                                     resource and solid
                                                     waste management
                                                     programs.
------------------------------------------------------------------------
a North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by the new
subpart. To determine whether your facility would be regulated by this
action, you should carefully examine the applicability criteria in
final 40 CFR 60.32f of subpart Cf. If you have any questions regarding
the applicability of the final subpart to a particular entity, contact
the person listed in the preceding FOR FURTHER INFORMATION CONTACT
section.

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 action is available through EPA's Technology Transfer Network
(TTN) Web site, a forum for information and technology exchange in
various areas of air pollution control. Following signature by the EPA
Administrator, the EPA will post a copy of this action at http://www.epa.gov/ttnatw01/landfill/landflpg.html. Following publication in
the Federal Register, the EPA will post the Federal Register version of
this final rule and technical documents at this same Web site.

III. Background

    The Emission Guidelines for MSW landfills were promulgated on March
12, 1996, and subsequently amended on June 16, 1998, February 24, 1999,
and April 10, 2000, to make technical corrections and clarifications.
Amendments were proposed on May 23, 2002, and September 8, 2006, to
address implementation issues, but those amendments were never
finalized. On July 17, 2014, the EPA issued an ANPRM for the MSW
landfills Emission Guidelines (79 FR 41772). The purpose of that action
was to request public input on controls and practices that could
further reduce emissions from existing MSW landfills and to evaluate
that input to determine if changes to the Emission Guidelines were
appropriate. On July 17, 2014, the EPA issued a concurrent proposal for
revised NSPS for new MSW landfills (79 FR 41796). On August 27, 2015
(80 FR 52100), the EPA proposed a review of the Emission Guidelines to
build on progress to date to (1) Achieve additional reductions in
emissions of LFG and its components, (2) account for changes in the
landfill industry and changes in operation of the landfills, including
the size, trends in GCCS installations, and age of landfills, as
reflected in new data, (3) provide new options for demonstrating
compliance, and (4) to complete efforts regarding unresolved
implementation issues. The EPA considered information it received in
response to the ANPRM (79 FR 41772) and Notice of Proposed Rulemaking
(80 FR 52100) for existing landfills in evaluating these final Emission
Guidelines. We are also finalizing some of the amendments proposed on
May 23, 2002, and September 8, 2006 to improve implementation of the
Emission Guidelines. The respective frameworks of NSPS and Emission
Guidelines have been similar since they were first promulgated in 1996
(e.g., size threshold, emission threshold, monitoring requirements,
etc). In response to public comments, which include implementation
concerns

associated with the potential for different approaches and requirements
between revised final rules, the EPA is finalizing similar requirements
for the NSPS and Emission Guidelines.

A. Landfill Gas Emissions and Climate Change

    In June 2013, President Obama issued a Climate Action Plan that
directed federal agencies to focus on ``assessing current emissions
data, addressing data gaps, identifying technologies and best practices
for reducing emissions, and identifying existing authorities and
incentive-based opportunities to reduce methane emissions.'' \8\
Methane is a potent greenhouse gas (GHG) that is 28-36 times greater
than carbon dioxide (CO2) and has an atmospheric life of
about 12 years.\9\ Because of methane's potency as a GHG and its
atmospheric life, reducing methane emissions is one of the best ways to
achieve near-term beneficial impact in mitigating global climate
change.
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    \8\ Executive Office of the President, ``The President's Climate
Action Plan'' June 2013. https://www.whitehouse.gov/sites/default/files/image/president27sclimateactionplan.pdf.
    \9\ The IPCC updates GWP estimates with each new assessment
report, and in the latest assessment report, AR5, the latest
estimate of the methane GWP ranged from 28-36, compared to a GWP of
25 in AR4. The impacts analysis in this final rule is based on the
100-year GWP from AR4 (25) instead of AR5 to be consistent with and
comparable to key Agency emission quantification programs such as
the Inventory of Greenhouse Gas Emissions and Sinks (GHG Inventory),
and the GHGRP.
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    The ``Climate Action Plan: Strategy to Reduce Methane Emissions''
\10\ (the Methane Strategy) was released in March 2014. The strategy
recognized the methane reductions achieved through the EPA's regulatory
and voluntary programs to date. It also directed the EPA to continue to
pursue emission reductions through regulatory updates and to encourage
LFG energy recovery through voluntary programs.
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    \10\ Executive Office of the President, ``Climate Action Plan
Strategy to Reduce Methane, March 2014. https://www.whitehouse.gov/sites/default/files/strategy_to_reduce_methane_emissions_2014-03-28_final.pdf.
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    The EPA recognized the climate benefits associated with reducing
methane emissions from landfills nearly 25 years ago. The 1991 NSPS
Background Information Document \11\ asserted that the reduction of
methane emissions from MSW landfills was one of many options available
to reduce global warming. The NSPS for MSW landfills, promulgated in
1996, also recognized the climate co-benefits of controlling methane
(61 FR 9917, March 12, 1996).
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    \11\ Air Emissions from Municipal Solid Waste Landfills-
Background Information for Proposed Standards and Guidelines, U.S.
EPA (EPA-450/3-90-011a) (NTIS PB 91-197061) page 2-15.
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    A recent study assessed EPA regulations and voluntary programs over
the period 1993-2013 and found that they were responsible for the
reduction of about 130 million metric tons of methane emissions (equal
to about 18 percent of the total U.S. methane emissions over that time
period), leading to a reduction in atmospheric concentrations of
methane of about 28 parts per billion in 2013 \12\ (compared to an
observed increase in methane concentrations of about 80 ppb over those
20 years).
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    \12\ Melvin, A.M.; Sarofim, M.C.; Crimmins, A.R., ``Climate
benefits of U.S. EPA programs and policies that reduced methane
emissions 1993-2013'', Environmental Science & Technology, 2016, in
press. http://pubs.acs.org/doi/pdf/10.1021/acs.est.6b00367. DOI
10.1021/acs.est.6b00367.
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    The review and final revision of the MSW landfills Emission
Guidelines capitalizes on additional opportunities to achieve methane
reductions while acknowledging historical agency perspectives and
research on climate, a charge from the President's Climate Action Plan,
the Methane Strategy, and improvements in the science surrounding GHG
emissions.
    LFG is a collection of air pollutants, including methane and NMOC.
LFG is typically composed of 50-percent methane, 50-percent
CO2, and less than 1-percent NMOC by volume. The NMOC
portion of LFG can contain various organic HAP and VOC. When the
Emission Guidelines and NSPS were promulgated in 1996, NMOC was
selected as a surrogate for MSW LFG emissions because NMOC contains the
air pollutants that at that time were of most concern due to their
adverse effects on public health and welfare. Today, methane's effects
on climate change are also considered important. In 2014, methane
emissions from MSW landfills represented 18.2 percent of total U.S.
methane emissions and 1.9 percent of total U.S. GHG emissions (in
carbon dioxide equivalent (CO2e)).\13\ In 2014, MSW
landfills continued to be the third largest source of human-related
methane emissions in the U.S., releasing an estimated 133.1 million
metric tons of CO2e. For these reasons and because
additional emissions reductions can be achieved at a reasonable cost,
the EPA is finalizing changes to the Emission Guidelines that are based
on reducing the NMOC and methane components of LFG.
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    \13\ Total U.S. methane emissions were 731 teragrams (Tg)
CO2e and total U.S. GHG emissions were 6,870.5 Tg in
2014. A teragram is equal to 1 million Mg. (A megagram is also known
as a metric ton, which is equal to 1.1 U.S. short tons or about
2,205 pounds.) U.S. EPA ``Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990-2014.'' Table ES-2. Available at http://www.epa.gov/climatechange/ghgemissions/usinventoryreport.html.
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B. What are the public health and welfare effects of landfill gas
emissions?

1. Public Health Effects of VOC and Various Organic HAP
    VOC emissions are precursors to both PM2.5 and ozone
formation. As documented in previous analyses (U.S. EPA, 2006 \14\,
2010 \15\, and 2014 \16\), exposure to PM2.5 and ozone is
associated with significant public health effects. PM2.5 is
associated with health effects, including premature mortality for
adults and infants, cardiovascular morbidity such as heart attacks, and
respiratory morbidity such as asthma attacks, acute bronchitis,
hospital admissions and emergency room visits, work loss days,
restricted activity days and respiratory symptoms, as well as welfare
impacts such as visibility impairment.\17\ Ozone is associated with
public health effects, including hospital and emergency department
visits, school loss days and premature mortality, as well as ecological
effects (e.g., injury to vegetation and climate change).\18\ Nearly 30
organic HAP have been identified in uncontrolled LFG, including
benzene, toluene, ethyl benzene, and vinyl chloride.\19\ Benzene is a
known human carcinogen.
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    \14\ U.S. EPA. RIA. National Ambient Air Quality Standards for
Particulate Matter, Chapter 5. Office of Air Quality Planning and
Standards, Research Triangle Park, NC. October 2006. Available on
the Internet at http://www.epa.gov/ttn/ecas/regdata/RIAs/Chapter%205-Benefits.pdf.
    \15\ U.S. EPA. RIA. National Ambient Air Quality Standards for
Ozone. Office of Air Quality Planning and Standards, Research
Triangle Park, NC. January 2010. Available on the Internet at http://www.epa.gov/ttn/ecas/regdata/RIAs/s1-supplemental_analysis_full.pdf.
    \16\ U.S. EPA. RIA. National Ambient Air Quality Standards for
Ozone. Office of Air Quality Planning and Standards, Research
Triangle Park, NC. December 2014. Available on the Internet at
http://www.epa.gov/ttnecas1/regdata/RIAs/20141125ria.pdf.
    \17\ U.S. EPA. Integrated Science Assessment for Particulate
Matter (Final Report). EPA-600-R-08-139F. National Center for
Environmental Assessment--RTP Division. December 2009. Available at
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546.
    \18\ U.S. EPA. Air Quality Criteria for Ozone and Related
Photochemical Oxidants (Final). EPA/600/R-05/004aF-cF. Washington,
DC: U.S. EPA. February 2006. Available on the Internet at http://cfpub.epa.gov/ncea/CFM/recordisplay.cfm?deid=149923.
    \19\ U.S. EPA. 1998. Office of Air and Radiation, Office of Air
Quality Planning and Standards. ``Compilation of Air Pollutant
Emission Factors, Fifth Edition, Volume I: Stationary Point and Area
Sources, Chapter 2: Solid Waste Disposal, Section 2.4: Municipal
Solid Waste Landfills''. Available at: http://www.epa.gov/ttn/chief/ap42/ch02/final/c02s04.pdf.

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2. Climate Impacts of Methane Emissions
    In addition to the improvements in air quality and resulting
benefits to human health and the non-climate welfare effects discussed
above, reducing emissions from landfills is expected to result in
climate co-benefits due to reductions of the methane component of LFG.
Methane is a potent GHG with a global warming potential (GWP) 28-36
times greater than CO2, which accounts for methane's
stronger absorption of infrared radiation per ton in the atmosphere,
but also its shorter lifetime (on the order of 12 years compared to
centuries or millennia for CO2).20 21 According
to the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment
Report, methane is the second leading long-lived climate forcer after
CO2 globally.\22\
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    \20\ IPCC, 2013: Climate Change 2013: The Physical Science
Basis. Contribution of Working Group I to the Fifth Assessment
Report of the Intergovernmental Panel on Climate Change [Stocker,
T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A.
Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA.
    \21\ As previously noted, this rulemaking uses the AR4 100-year
GWP value for methane (25), rather than AR5, for CO2
equivalency calculations to be consistent with and comparable to key
Agency emission quantification programs such as the Inventory of
Greenhouse Gas Emissions and Sinks (GHG Inventory), and the GHGRP.
    \22\ IPCC, 2013: Climate Change 2013: The Physical Science
Basis. Contribution of Working Group I to the Fifth Assessment
Report of the Intergovernmental Panel on Climate Change [Stocker,
T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A.
Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA.
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    Methane is also a precursor to ground-level ozone, which can cause
a number of harmful effects on public health and the environment.
Additionally, ozone is a short-lived climate forcer that contributes to
global warming.
    In 2009, based on a large body of robust and compelling scientific
evidence, the EPA Administrator issued an Endangerment Finding under
CAA section 202(a)(1).\23\ In the Endangerment Finding, the
Administrator found that the current, elevated concentrations of GHGs
in the atmosphere--already at levels unprecedented in human history--
may reasonably be anticipated to endanger public health and welfare of
current and future generations in the U.S. We summarize these adverse
effects on public health and welfare briefly here.
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    \23\ ``Endangerment and Cause or Contribute Findings for
Greenhouse Gases Under Section 202(a) of the Clean Air Act,'' 74 FR
66496 (Dec. 15, 2009) (``Endangerment Finding'').
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3. Public Health Impacts Detailed in the 2009 Endangerment Finding
    The 2009 Endangerment Finding documented that climate change caused
by human emissions of GHGs threatens the health of Americans. By
raising average temperatures, climate change increases the likelihood
of heat waves, which are associated with increased deaths and
illnesses. While climate change also increases the likelihood of
reductions in cold-related mortality, evidence indicates that the
increases in heat mortality will be larger than the decreases in cold
mortality in the United States. Compared to a future without climate
change, climate change is expected to increase ozone pollution over
broad areas of the U.S., including in the largest metropolitan areas
with the worst ozone problems, and thereby increase the risk of
morbidity and mortality. Climate change is also expected to cause more
intense hurricanes and more frequent and intense storms of other types
and heavy precipitation, with impacts on other areas of public health,
such as the potential for increased deaths, injuries, infectious and
waterborne diseases, and stress-related disorders. Children, the
elderly, and the poor are among the most vulnerable to these climate-
related health effects.
4. Public Welfare Impacts Detailed in the 2009 Endangerment Finding
    The 2009 Endangerment Finding documented that climate change
impacts touch nearly every aspect of public welfare. Among the multiple
threats caused by human emissions of GHGs, climate changes are expected
to place large areas of the country at serious risk of reduced water
supplies, increased water pollution, and increased occurrence of
extreme events such as floods and droughts. Coastal areas are expected
to face a multitude of increased risks, particularly from rising sea
level and increases in the severity of storms. These communities face
storm and flooding damage to property, or even loss of land due to
inundation, erosion, wetland submergence and habitat loss.
    Impacts of climate change on public welfare also include threats to
social and ecosystem services. Climate change is expected to result in
an increase in peak electricity demand. Extreme weather from climate
change threatens energy, transportation, and water resource
infrastructure. Climate change may also exacerbate ongoing
environmental pressures in certain settlements, particularly in Alaskan
indigenous communities, and is very likely to fundamentally rearrange
U.S. ecosystems over the 21st century. Though some benefits may balance
adverse effects on agriculture and forestry in the next few decades,
the body of evidence points towards increasing risks of net adverse
impacts on U.S. food production, agriculture and forest productivity as
temperature continues to rise. These impacts are global and may
exacerbate problems outside the U.S. that raise humanitarian, trade,
and national security issues for the U.S.
5. New Scientific Assessments
    In 2009, based on a large body of robust and compelling scientific
evidence, the EPA Administrator issued the Endangerment Finding under
CAA section 202(a)(1).\24\ In the Endangerment Finding, the
Administrator found that the current, elevated concentrations of GHGs
in the atmosphere--already at levels unprecedented in human history--
may reasonably be anticipated to endanger public health and welfare of
current and future generations in the U.S. The D.C. Circuit later
upheld the Endangerment Finding from all challenges. Coalition for
Responsible Regulation v. EPA, 684 F. 3d 102, 116-26 (D.C. Cir. 2012).
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    \24\ ``Endangerment and Cause or Contribute Findings for
Greenhouse Gases Under Section 202(a) of the Clean Air Act,'' 74 FR
66496 (Dec. 15, 2009) (``Endangerment Finding'').
---------------------------------------------------------------------------

    Since the administrative record concerning the Endangerment Finding
closed following the EPA's 2010 Reconsideration Denial, the climate has
continued to change, with new records being set for a number of climate
indicators such as global average surface temperatures, Arctic sea ice
retreat, CO2 concentrations, and sea level rise.
Additionally, a number of major scientific assessments have been
released that improve understanding of the climate system and
strengthen the case that GHGs endanger public health and welfare both
for current and future generations. These assessments, from the
Intergovernmental Panel on Climate Change (IPCC), the U.S. Global
Change Research Program (USGCRP), and the National Research Council
(NRC), include: IPCC's 2012 Special Report on Managing the Risks of
Extreme Events and Disasters to Advance Climate Change Adaptation
(SREX) and the 2013-2014 Fifth Assessment Report (AR5), the USGCRP's
2014 National Climate Assessment, Climate Change Impacts in the United
States (NCA3), and the NRC's 2010 Ocean Acidification: A National
Strategy to Meet the Challenges of a Changing

Ocean (Ocean Acidification), 2011 Report on Climate Stabilization
Targets: Emissions, Concentrations, and Impacts over Decades to
Millennia (Climate Stabilization Targets), 2011 National Security
Implications for U.S. Naval Forces (National Security Implications),
2011 Understanding Earth's Deep Past: Lessons for Our Climate Future
(Understanding Earth's Deep Past), 2012 Sea Level Rise for the Coasts
of California, Oregon, and Washington: Past, Present, and Future, 2012
Climate and Social Stress: Implications for Security Analysis (Climate
and Social Stress), and 2013 Abrupt Impacts of Climate Change (Abrupt
Impacts) assessments.
    The conclusions of the recent scientific assessments confirm and
strengthen the science that supported the 2009 Endangerment Finding.
The NCA3 indicates that climate change ``threatens human health and
well-being in many ways, including impacts from increased extreme
weather events, wildfire, decreased air quality, threats to mental
health, and illnesses transmitted by food, water, and disease-carriers
such as mosquitoes and ticks.'' \25\ Most recently, the USGCRP released
a new assessment, ``The Impacts of Climate Change on Human Health in
the United States: A Scientific Assessment'' (also known as the USGCRP
Climate and Health Assessment). This assessment finds that ``climate
change impacts endanger our health'' and that in the United States we
have ``observed climate-related increases in our exposure to elevated
temperatures; more frequent, severe, or longer lasting extreme events;
diseases transmitted through food, water, or disease vectors such as
ticks and mosquitoes; and stresses to mental health and well-being.''
The assessment determines that ``[e]very American is vulnerable to the
health impacts associated with climate change.'' Climate warming will
also likely ``make it harder for any given regulatory approach to
reduce ground-level ozone pollution'', and, unless offset by reductions
of ozone precursors, it is likely that ``climate-driven increases in
ozone will cause premature deaths, hospital visits, lost school days,
and acute respiratory symptoms.'' \26\
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    \25\ USGCRP, Third National Climate Assessment, p. 221.
    \26\ See also Kleeman, M.J., S.-H. Chen, and R.A. Harley. 2010.
Climate change impact on air quality in California: Report to the
California Air Resources Board. http://www.arb.ca.gov/research/apr/past/04-349.pdf.
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    Assessments state that certain populations are particularly
vulnerable to climate change. The USGCRP Climate and Health Assessment
assesses several disproportionately vulnerable populations, including
those with low income, some communities of color, immigrant groups,
indigenous peoples, pregnant women, vulnerable occupational groups,
persons with disabilities, and persons with preexisting or chronic
medical conditions. The Climate and Health Assessment also concludes
that children's unique physiology and developing bodies contribute to
making them particularly vulnerable to climate change. Children also
have unique behaviors and exposure pathways that could increase their
exposure to environmental stressors, like contaminants in dust or
extreme heat events. Impacts from climate change on children are likely
from heat waves, air pollution, infectious and waterborne illnesses,
disruptions in food safety and security, and mental health effects
resulting from extreme weather events. For example, climate change can
disrupt food safety and security by significantly reducing food
quality, availability and access. Children are more susceptible to this
disruption because nutrition is important during critical windows of
development and growth. Older people are at much higher risk of
mortality during extreme heat events and pre-existing health conditions
also make older adults susceptible to cardiac and respiratory impacts
of air pollution and to more severe consequences from infectious and
waterborne diseases. Limited mobility among older adults can also
increase health risks associated with extreme weather and floods.
    The new assessments also confirm and strengthen the science that
supported the 2009 Endangerment Finding. The NRC assessment
Understanding Earth's Deep Past stated that ``[b]y the end of this
century, without a reduction in emissions, atmospheric CO2 is projected
to increase to levels that Earth has not experienced for more than 30
million years.'' In fact, that assessment stated that ``the magnitude
and rate of the present GHG increase place the climate system in what
could be one of the most severe increases in radiative forcing of the
global climate system in Earth history.'' \27\ Because of these
unprecedented changes in atmospheric concentrations, several
assessments state that we may be approaching critical, poorly
understood thresholds. The NRC Abrupt Impacts report analyzed the
potential for abrupt climate change in the physical climate system and
abrupt impacts of ongoing changes that, when thresholds are crossed,
could cause abrupt impacts for society and ecosystems. The report
considered destabilization of the West Antarctic Ice Sheet (which could
cause 3-4 m of potential sea level rise) as an abrupt climate impact
with unknown but probably low probability of occurring this century.
The report categorized a decrease in ocean oxygen content (with
attendant threats to aerobic marine life); increase in intensity,
frequency, and duration of heat waves; and increase in frequency and
intensity of extreme precipitation events (droughts, floods,
hurricanes, and major storms) as climate impacts with moderate risk of
an abrupt change within this century. The NRC Abrupt Impacts report
also analyzed the threat of rapid state changes in ecosystems and
species extinctions as examples of an irreversible impact that is
expected to be exacerbated by climate change. Species at most risk
include those whose migration potential is limited, whether because
they live on mountaintops or fragmented habitats with barriers to
movement, or because climatic conditions are changing more rapidly than
the species can move or adapt. While some of these abrupt impacts may
be of low or moderate probability in this century, the probability for
a significant change in many of these processes after 2100 was judged
to be higher, with severe impacts likely should the abrupt change
occur. Future temperature changes will be influenced by what emissions
path the world follows. In its high emission scenario, the IPCC AR5
projects that global temperatures by the end of the century will likely
be 2.6 [deg]C to 4.8 [deg]C (4.7 to 8.6 [deg]F) warmer than today.
There is very high confidence that temperatures on land and in the
Arctic will warm even faster than the global average. However,
according to the NCA3, significant reductions in emissions would lead
to noticeably less future warming beyond mid-century, and therefore
less impact to public health and welfare. According to the NCA3,
regions closer to the poles are projected to receive more
precipitation, while the dry subtropics expand (colloquially, this has
been summarized as wet areas getting wet and dry regions getting
drier), while ``[t]he widespread trend of increasing heavy downpours is
expected to continue, with precipitation becoming less frequent but
more intense.'' Meanwhile, the NRC Climate Stabilization Targets
assessment found that the area burned by wildfire in parts of western
North America is expected to grow by 2 to 4 times for 1 [deg]C (1.8
[deg]F) of warming. The NCA also found that

``[e]xtrapolation of the present observed trend suggests an essentially
ice-free Arctic in summer before mid-century.'' Retreating snow and
ice, and emissions of carbon dioxide and methane released from thawing
permafrost, are very likely to amplify future warming.
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    \27\ National Research Council, Understanding Earth's Deep Past,
p. 138.
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    Since the 2009 Endangerment Finding, the IPCC AR5, the USGCRP NCA3,
and three of the new NRC assessments provide estimates of projected
global average sea level rise. These estimates, while not always
directly comparable as they assume different emissions scenarios and
baselines, are at least 40 percent larger than, and in some cases more
than twice as large as, the projected rise estimated in the IPCC AR4
assessment, which was referred to in the 2009 Endangerment Finding. The
NRC Sea Level Rise assessment projects a global average sea level rise
of 0.5 to 1.4 meters by 2100. The NRC National Security Implications
assessment suggests that ``the Department of the Navy should expect
roughly 0.4 to 2 meters global average sea-level rise by 2100.'' The
NRC Climate Stabilization Targets assessment states that a global
average temperature increase of 3 [deg]C will lead to a global average
sea level rise of 0.5 to 1 meter by 2100. These NRC and IPCC
assessments continue to recognize and characterize the uncertainty
inherent in accounting for melting ice sheets in sea level rise
projections.
    In addition to future impacts, the NCA3 emphasizes that climate
change driven by human emissions of GHGs is already happening now and
it is happening in the U.S. According to the IPCC AR5 and the NCA3,
there are a number of climate-related changes that have been observed
recently, and these changes are projected to accelerate in the future:
     The planet warmed about 0.85 [deg]C (1.5 [deg]F) from 1880
to 2012. It is extremely likely (>95 percent probability) that human
influence was the dominant cause of the observed warming since the mid-
20th century, and likely (>66 percent probability) that human influence
has more than doubled the probability of occurrence of heat waves in
some locations. In the Northern Hemisphere, the last 30 years were
likely the warmest 30 year period of the last 1400 years.
     Global sea levels rose 0.19 m (7.5 inches) from 1901 to
2010. Contributing to this rise was the warming of the oceans and
melting of land ice. It is likely that 275 gigatons per year of ice
melted from land glaciers (not including ice sheets) since 1993, and
that the rate of loss of ice from the Greenland and Antarctic ice
sheets increased substantially in recent years, to 215 gigatons per
year and 147 gigatons per year respectively since 2002. For context,
360 gigatons of ice melt is sufficient to cause global sea levels to
rise 1 mm.
     Annual mean Arctic sea ice has been declining at 3.5 to
4.1 percent per decade, and Northern Hemisphere snow cover extent has
decreased at about 1.6 percent per decade for March and 11.7 percent
per decade for June.
     Permafrost temperatures have increased in most regions
since the 1980s, by up to 3 [deg]C (5.4 [deg]F) in parts of Northern
Alaska.
     Winter storm frequency and intensity have both increased
in the Northern Hemisphere. The NCA3 states that the increases in the
severity or frequency of some types of extreme weather and climate
events in recent decades can affect energy production and delivery,
causing supply disruptions, and compromise other essential
infrastructure such as water and transportation systems.
    In addition to the changes documented in the assessment literature,
there have been other climate milestones of note. According to the
National Oceanic and Atmospheric Administration (NOAA), methane
concentrations in 2014 were about 1,823 parts per billion, 150 percent
higher than concentrations were in 1750. After a few years of nearly
stable concentrations from 1999 to 2006, methane concentrations have
resumed increasing at about 5 parts per billion per year.\28\
Concentrations today are likely higher than they have been for at least
the past 800,000 years.\29\ Arctic sea ice has continued to decline,
with September of 2012 marking the record low in terms of Arctic sea
ice extent, 40 percent below the 1979-2000 median. Sea level has
continued to rise at a rate of 3.2 mm per year (1.3 inches/decade)
since satellite observations started in 1993, more than twice the
average rate of rise in the 20th century prior to 1993.\30\ And 2015
was the warmest year globally in the modern global surface temperature
record, going back to 1880, breaking the record previously held by
2014; this now means that the last 15 years have been 15 of the 16
warmest years on record.\31\
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    \28\ Ed Dlugokencky, NOAA/ESRL (www.esrl.noaa.gov/gmd/ccgg/trends_ch4/).
    \29\ U.S. Environmental Protection Agency. 2014. Climate change
indicators in the United States, 2014. Third edition. EPA 430-R-14-
004. www.epa.gov/climatechange/indicators.
    \30\ Blunden, J., and D. S. Arndt, Eds., 2015: State of the
Climate in 2014. Bull. Amer. Meteor. Soc., 96 (7), S1-S267.
    \31\ http://www.ncdc.noaa.gov/sotc/global/201513.
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    These assessments and observed changes raise concerns that reducing
emissions of GHGs across the globe is necessary in order to avoid the
worst impacts of climate change, and underscore the urgency of reducing
emissions now. In 2011 the NRC Committee on America's Climate Choices
listed a number of reasons ``why it is imprudent to delay actions that
at least begin the process of substantially reducing emissions.'' \32\
For example, they stated:
---------------------------------------------------------------------------

    \32\ NRC, 2011: America's Climate Choices, The National
Academies Press, p. 2.
---------------------------------------------------------------------------

     The faster emissions are reduced, the lower the risks
posed by climate change. Delays in reducing emissions could commit the
planet to a wide range of adverse impacts, especially if the
sensitivity of the climate to GHGs is on the higher end of the
estimated range.
     Waiting for unacceptable impacts to occur before taking
action is imprudent because the effects of GHG emissions do not fully
manifest themselves for decades and, once manifested, many of these
changes will persist for hundreds or even thousands of years.
     In the committee's judgment, the risks associated with
maintaining business as usual are a much greater concern than the risks
associated with engaging in strong response efforts.

Overview of Climate Change Impacts in the United States

    The NCA3 assessed the climate impacts in eight regions of the U.S.,
noting that changes in physical climate parameters such as
temperatures, precipitation, and sea ice retreat were already having
impacts on forests, water supplies, ecosystems, flooding, heat waves,
and air quality. The U.S. average temperatures have similarly increased
by 1.3 to 1.9 degrees F since 1895, with most of that increase
occurring since 1970, and the most recent decade was the U.S.'s hottest
as well as the world's hottest. Moreover, the NCA3 found that future
warming is projected to be much larger than recent observed variations
in temperature, with 2 to 4 degrees F warming expected in most areas of
the U.S. over the next few decades, and up to 10 degrees F possible by
the end of the century assuming continued increases in emissions.
Extreme heat events will continue to become more common, and extreme
cold less common. Additionally, precipitation is considered likely to
increase in the northern states, decrease in the southern states, and
with the heaviest precipitation events projected to increase
everywhere.

    In the Northeast, temperatures increased almost 2[emsp14][deg]F
from 1895 to 2011, precipitation increased by about 5 inches (10
percent), and sea level rise of about a foot has led to an increase in
coastal flooding. In the future, if emissions continue to increase, the
Northeast is projected to experience 4.5 to 10[emsp14][deg]F of warming
by the 2080s. This is expected to lead to more heat waves, coastal and
river flooding, and intense precipitation events. Sea levels in the
Northeast are expected to increase faster than the global average
because of subsidence, and models suggest changing ocean currents may
further increase the rate of sea level rise.
    In the Southeast, average annual temperature during the last
century cycled between warm and cool periods. A warm peak occurred
during the 1930s and 1940s followed by a cool period and temperatures
then increased again from 1970 to the present by an average of
2[emsp14][deg]F. Louisiana has already lost 1,880 square miles of land
in the last 80 years due to sea level rise and other contributing
factors. The Southeast is exceptionally vulnerable to sea level rise,
extreme heat events, hurricanes, and decreased water availability.
Major risks of further warming include significant increases in the
number of hot days (95[emsp14][deg]F or above) and decreases in
freezing events, as well as exacerbated ground level ozone in urban
areas. Projections suggest that there may be fewer hurricanes in the
Atlantic in the future, but they will be more intense, with more
Category 4 and 5 storms. The NCA identified New Orleans, Miami, Tampa,
Charleston, and Virginia Beach as cities at particular risk of
flooding.
    In the Northwest, temperatures increased by about 1.3[emsp14][deg]F
between 1895 and 2011. Snowpack in the Northwest is an important
freshwater source for the region. More precipitation falling as rain
instead of snow has reduced the snowpack, and warmer springs have
corresponded to earlier snowpack melting and reduced stream flows
during summer months. Drier conditions have increased the extent of
wildfires in the region. Average annual temperatures are projected to
increase by 3.3[emsp14][deg]F to 9.7[emsp14][deg]F by the end of the
century (depending on future global GHG emissions), with the greatest
warming is expected during the summer. Continued increases in global
GHG emissions are projected to result in up to a 30 percent decrease in
summer precipitation. Warmer waters are expected to increase disease
and mortality in important fish species, including Chinook and sockeye
salmon.
    In Alaska, temperatures have changed faster than anywhere else in
the U.S. Annual temperatures increased by about 3[emsp14][deg]F in the
past 60 years. Warming in the winter has been even greater, rising by
an average of 6[emsp14][deg]F. Glaciers in Alaska are melting at some
of the fastest rates on Earth. Permafrost soils are also warming and
beginning to thaw. Drier conditions had already contributed to more
large wildfires in the 10 years prior to the NCA3 than in any previous
decade since the 1940s, when recordkeeping began, and subsequent years
have seen even more wildfires. By the end of this century, continued
increases in GHG emissions are expected to increase temperatures by 10
to 12[emsp14][deg]F in the northernmost parts of Alaska, by 8 to
10[emsp14][deg]F in the interior, and by 6 to 8[emsp14][deg]F across
the rest of the state. These increases will exacerbate ongoing arctic
sea ice loss, glacial melt, permafrost thaw and increased wildfire, and
threaten humans, ecosystems, and infrastructure.
    In the Southwest, temperatures are now about 2[emsp14][deg]F higher
than the past century, and are already the warmest that region has
experienced in at least 600 years. The NCA notes that there is evidence
that climate-change induced warming on top of recent drought has
influenced tree mortality, wildfire frequency and area, and forest
insect outbreaks. At the time of publication of the NCA, even before
the last 2 years of extreme drought in California, tree ring data was
already indicating that the region might be experiencing its driest
period in 800 years. The Southwest is projected to warm an additional
5.5 to 9.5[emsp14][deg]F over the next century if emissions continue to
increase. Winter snowpack in the Southwest is projected to decline
(consistent with recent record lows), reducing the reliability of
surface water supplies for cities, agriculture, cooling for power
plants, and ecosystems. Sea level rise along the California coast is
projected to worsen coastal erosion, increase flooding risk for coastal
highways, bridges, and low-lying airports, and pose a threat to
groundwater supplies in coastal cities. Also, ``[t]he combination of a
longer frost-free season, less frequent cold air outbreaks, and more
frequent heat waves accelerates crop ripening and maturity, reduces
yields of corn, tree fruit, and wine grapes, stresses livestock, and
increases agricultural water consumption.'' Increased drought, higher
temperatures, and bark beetle outbreaks are likely to contribute to
continued increases in wildfires.
    The rate of warming in the Midwest has markedly accelerated over
the past few decades. Temperatures rose by more than 1.5[emsp14][deg]F
from 1900 to 2010, but between 1980 and 2010 the rate of warming was
three times faster than from 1900 through 2010. Precipitation generally
increased over the last century, with much of the increase driven by
intensification of the heaviest rainfalls. Several types of extreme
weather events in the Midwest (e.g., heat waves and flooding) have
already increased in frequency and/or intensity due to climate change.
In the future, if emissions continue increasing, the Midwest is
expected to experience 5.6 to 8.5[emsp14][deg]F of warming by the
2080s, leading to more heat waves. Specific vulnerabilities highlighted
by the NCA include long-term decreases in agricultural productivity,
changes in the composition of the region's forests, increased public
health threats from heat waves and degraded air and water quality,
negative impacts on transportation and other infrastructure associated
with extreme rainfall events and flooding, and risks to the Great Lakes
including shifts in invasive species, increases in harmful algal
blooms, and declining beach health.
    High temperatures (more than 100[emsp14][deg]F in the Southern
Plains and more than 95[emsp14][deg]F in the Northern Plains) are
projected to occur much more frequently by mid-century. Increases in
extreme heat will increase heat stress for residents, energy demand for
air conditioning, and water losses. In Hawaii, other Pacific islands,
and the Caribbean, rising air and ocean temperatures, shifting rainfall
patterns, changing frequencies and intensities of storms and drought,
decreasing base flow in streams, rising sea levels, and changing ocean
chemistry will affect ecosystems on land and in the oceans, as well as
local communities, livelihoods, and cultures. Low islands are
particularly at risk.
    In Hawaii and the Pacific islands, ``[w]armer oceans are leading to
increased coral bleaching events and disease outbreaks in coral reefs,
as well as changed distribution patterns of tuna fisheries. Ocean
acidification will reduce coral growth and health. Warming and
acidification, combined with existing stresses, will strongly affect
coral reef fish communities.'' For Hawaii and the Pacific islands,
future sea surface temperatures are projected to increase
2.3[emsp14][deg]F by 2055 and 4.7[emsp14][deg]F by 2090 under a
scenario that assumes continued increases in emissions.
    Methane Specific Impacts. Methane is also a precursor to ground-
level ozone, which can cause a number of harmful effects on health and
the environment. Additionally, ozone is a short-lived climate forcer
that contributes to global

warming. In remote areas, methane is an important precursor to
tropospheric ozone formation.\33\ Almost half of the global annual mean
ozone increase since preindustrial times is believed to be due to
anthropogenic methane.\34\ Projections of future emissions also
indicate that methane is likely to be a key contributor to ozone
concentrations in the future.\35\ Unlike nitrogen oxide
(NOX) and VOC, which affect ozone concentrations regionally
and at hourly time scales, methane emissions affect ozone
concentrations globally and on decadal time scales given methane's
relatively long atmospheric lifetime compared to these other ozone
precursors.\36\ Reducing methane emissions, therefore, may contribute
to efforts to reduce global background ozone concentrations that
contribute to the incidence of ozone-related health
effects.37 38 39 These benefits are global and occur in both
urban and rural areas.
---------------------------------------------------------------------------

    \33\ U.S. EPA. 2013. ``Integrated Science Assessment for Ozone
and Related Photochemical Oxidants (Final Report).'' EPA-600-R-10-
076F. National Center for Environmental Assessment--RTP Division.
Available at www.epa.gov/ncea/isa/.
    \34\ Ibid.
    \35\ Ibid.
    \36\ Ibid.
    \37\ West, J.J., Fiore, A.M. 2005. ``Management of tropospheric
ozone by reducing methane emissions.'' Environ. Sci. Technol.
39:4685-4691.
    \38\ Anenberg, S.C., et al. 2009. ``Intercontinental impacts of
ozone pollution on human mortality,'' Environ. Sci. & Technol. 43:
6482-6487.
    \39\ Sarofim, M.C., Waldhoff, S.T., Anenberg, S.C. 2015.
``Valuing the Ozone-Related Health Benefits of Methane Emission
Controls,'' Environ. Resource Econ. DOI 10.1007/s10640-015-9937-6.
---------------------------------------------------------------------------

C. What is the EPA's authority for reviewing the Emission Guidelines?

    The EPA is not statutorily obligated to conduct a review of the
Emission Guidelines, but has the discretionary authority to do so when
circumstances indicate that it is appropriate. The EPA has determined
that it is appropriate to conduct a review of and finalize certain
changes to the Emission Guidelines due to changes in the landfill
industry and changes in operation of the landfills, including the size,
trends in GCCS installations (such as the types of MSW landfills that
have installed gas collection systems), and age of landfills since the
Emission Guidelines were promulgated in 1996 and the opportunities for
significant reductions in methane and other pollutants at reasonable
cost. The EPA compiled new information on MSW landfills through data
collection efforts for a statutorily mandated review of the NSPS,
public comments received on the NSPS proposal, and public comments
received on an ANPRM, as well as a proposed rulemaking for a review of
the Emission Guidelines. This information allowed the EPA to conduct an
assessment of current practices, emissions and potential for additional
emission reductions.

D. What is the purpose and scope of this action?

    The purpose of this action is to (1) Present the results of the
EPA's review of the Emission Guidelines, (2) finalize revisions to the
Emission Guidelines based on that review, and (3) resolve or provide
clarification regarding several implementation issues that were
addressed in prior proposed amendments published on May 23, 2002 (67 FR
36475) and September 8, 2006 (71 FR 53271) as they apply to existing
sources. The final revisions appear in 40 CFR part 60, subpart Cf.\40\
Although the EPA is not required to respond to comments received on the
July 17, 2014, ANPRM (79 FR 41772) for the MSW landfills Emission
Guidelines or comments it received on the concurrent proposal for
revised NSPS for new MSW landfills in this document, the EPA is
summarizing several comments it received to provide a framework and
support the rationale for the final revisions to the Emission
Guidelines.
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    \40\ Rather than merely updating 40 CFR part 60, subpart Cc, the
existing emissions guidelines, the EPA has determined that the most
appropriate way to proceed is to establish a new subpart that
includes both the verbatim restatement of certain provisions in the
existing Emission Guidelines and revisions to, or the addition of,
other provisions.
---------------------------------------------------------------------------

E. How would the changes in applicability affect sources currently
subject to subparts Cc and WWW?

    Landfills currently subject to 40 CFR part 60, subparts Cc and WWW,
are considered ``existing'' with the promulgation of this new subpart
Cf and are ultimately affected by any changes to the Emission
Guidelines resulting from this review. Each MSW landfill for which
construction, modification, or reconstruction commenced on or before
July 17, 2014, the date of proposal of the standard for new landfills
under subpart XXX, is an existing source as of the effective date of
this rule. Under CAA section 111, a source is either new, i.e.,
construction, modification, or reconstruction commenced after a
proposed NSPS is published in the Federal Register (CAA section
111(a)(1)) or existing, i.e., any source other than a new source (CAA
section 111(a)(6)). Because the revised Emission Guidelines apply to
existing sources, any source that is not subject to subpart XXX will be
subject to the revised Emission Guidelines. Any existing MSW landfill
that modifies or reconstructs after July 17, 2014 would become a new
source subject to the NSPS subpart XXX.
    Consistent with the general approach evinced by CAA section 111,
sources currently subject to subpart WWW would need to continue to
comply with the requirements in that rule until they become subject to
more stringent requirements in the revised Emission Guidelines as
implemented through a revised state or federal plan. The current
Emission Guidelines, subpart Cc, refer to subpart WWW for their
substantive requirements. That is, the requirements regarding the
installation and operation of a well-designed and well-operated GCCS
and compliance with the specified emission limits are the same in both
rules. Thus, because the EPA is finalizing its proposal to revise the
Emission Guidelines to increase their stringency, a landfill currently
subject to 40 CFR part 60, subpart WWW, would need to comply with the
more stringent requirements in a revised state plan or federal plan
implementing the revised Emission Guidelines (40 CFR part 60, subpart
Cf). States with designated facilities must develop (or revise) and
submit a state plan to the EPA within 9 months of promulgation of any
revisions to the Emission Guidelines (40 CFR 60.23). Any revisions to
an existing state plan and any newly adopted state plan must be
established following the requirements of 40 CFR part 60, subpart B. To
assist regulatory agencies in preparing state plans, the EPA developed
the document ``Municipal Solid Waste Landfills, Volume 2: Summary of
Requirements for Section 111(d) State Plans for Implementing the
Municipal Solid Waste Landfill Emission Guidelines.'' This volume
describes the elements of a state plan and explains the state plan
development and review process. The requirements include making the
state plan publically available and providing the opportunity for
public discussion. MSW Landfills, Volume 2 is available on the TTN Web
site at https://www3.epa.gov/ttn/atw/landfill/landflpg.html. Note that
MSW Landfills, Volume 2 was written for implementing the 1996 Emission
Guidelines and contains a schedule corresponding to the 1996 Emission
Guidelines. For these 2016 Emission Guidelines, state plans are due May
30, 2017.
    Once the EPA receives a complete state plan or plan revision, and
completes its review of that plan or plan revision, the EPA will
propose the plan or plan revision for approval or disapproval. The EPA
will approve or disapprove the plan or plan revision

according to the schedule in 40 CFR part 60, subpart B. The EPA will
publish notice of state plan approvals or disapprovals in the Federal
Register and will include an explanation of its decision. The EPA also
intends to revise the existing federal plan (40 CFR part 62, subpart
GGG) to incorporate the changes and other requirements adopted in this
final action revising the Emission Guidelines. The revised federal plan
will apply in states that have either never submitted a state plan or
not received approval of any necessary revised state plan until such
time as an initial state plan or revised state plan is approved.
Fifteen states and territories implement the original Emission
Guidelines promulgated at subpart Cc under the Federal Plan (40 CFR
part 62, subpart GGG) The revised federal plan would also apply in
Indian country unless and until replaced by a tribal implementation
plan (TIP).\41\
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    \41\ Indian tribes may, but are not required to, seek approval
for treatment in a manner similar to a state for purposes of
developing a tribal implementation plan implementing the Emission
guidelines. If a tribe obtains such approval and submits a proposed
TIP, the EPA will use the same criteria and follow the same
procedure in approving that plan as it does with state plans. The
federal plan will apply to all affected facilities located in Indian
country unless and until EPA approves an applicable TIP.
---------------------------------------------------------------------------

    Because many of the landfills currently subject to 40 CFR part 60,
subparts Cc and WWW, are closed, the EPA is finalizing provisions to
minimize the burden on these closed landfills while continuing to
protect air quality, as discussed in sections V.C and VI.C of this
preamble.

IV. Summary of the Final Emission Guidelines

A. What are the control requirements?

1. Design Capacity and Emissions Thresholds
    The revised Emission Guidelines retain the current design capacity
thresholds of 2.5 million Mg and 2.5 million m\3\, but reduce the NMOC
emission threshold for the installation and removal of a GCCS from 50
Mg/yr to 34 Mg/yr for landfills that are not closed as of September 27,
2017. An MSW landfill that exceeds the design capacity thresholds must
install and start up a GCCS within 30 months after reporting that LFG
emissions reach or exceed a NMOC level of 34 Mg/yr NMOC. The owner or
operator of a landfill may control the gas by routing it to a non-
enclosed flare, an enclosed combustion device, or a treatment system
that processes the collected gas for subsequent sale or beneficial use.
2. Tier 4
    The current Emission Guidelines (40 CFR part 60, subpart Cc)
provide that owners or operators determine whether the landfill has
exceeded the NMOC emissions threshold using one of three available
modeling procedures, known as Tiers 1, 2, and 3. The EPA is finalizing
in subpart Cf an additional optional methodology based on site-specific
surface methane emissions to determine when a landfill must install and
operate a GCCS. This alternative emission threshold methodology,
referred to as ``Tier 4,'' is based on SEM and demonstrates that
surface methane emissions are below a specific threshold. The Tier 4
SEM demonstration allows certain landfills that exceed modeled NMOC
emission rates using Tier 1 or 2 to demonstrate that site-specific
surface methane emissions are below a surface concentration threshold
(a landfill need not model emissions under Tier 3 before using Tier 4).
A landfill that can demonstrate that surface emissions are below 500
ppm for four consecutive quarters does not trigger the requirement to
install a GCCS even if Tier 1, 2, or 3 calculations indicate that the
34 Mg/yr threshold has been exceeded. Owners or operators continue to
keep detailed records of each quarterly monitoring demonstration and
must submit a Tier 4 surface emissions report annually. If a landfill
measures a surface emissions reading of greater than 500 ppm methane,
the landfill must submit a GCCS design plan and install and operate a
GCCS.
    Tier 4 is based on the results of quarterly site-specific methane
emissions monitoring of the perimeter of the landfill and entire
surface of the landfill along a pattern that traverses the landfill at
30-meter (98-ft) intervals, in addition to monitoring areas where
visual observations may indicate elevated concentrations of LFG, such
as distressed vegetation and cracks or seeps in the cover and all cover
penetrations. If the landfill opts to use Tier 4 for its emission
threshold determination and there is any measured concentration of
methane of 500 ppm or greater from the surface of the landfill, the
owner or operator must install a GCCS, and the landfill cannot go back
to using Tiers 1, 2, or 3 modeling to demonstrate that emissions are
below the NMOC threshold.
    Tier 4 is allowed only if the landfill owner or operator can
demonstrate that NMOC emissions are greater than or equal to 34 Mg/yr,
but less than 50 Mg/yr using Tier 1 or Tier 2. If both Tier 1 and Tier
2 indicate NMOC emissions of 50 Mg/yr or greater, Tier 4 cannot be
used. In addition, a wind barrier must be used for Tier 4 when the
average wind speed exceeds 4 miles per hour (mph)(or 2 meters per
second), or gusts are above 10 mph. Tier 4 measurements cannot be
conducted if the average wind speed exceeds 25 mph. Wind speed must be
measured with an on-site anemometer with a continuous recorder and data
logger for the entire duration of the monitoring event. The average
wind speed must be determined at 5-minute intervals. The gust must be
determined at 3-second intervals. Further, when conducting Tier 4
monitoring, the sampling probe must be held no more than 5 centimeters
above the landfill (e.g., using a mechanical device such as a wheel on
a pole). Tier 4 measurements cannot be conducted if the average wind
speed exceeds 25 mph
    In addition, landfills with a non-regulatory GCCS are allowed to
operate the GCCS during the Tier 4 SEM demonstration, however, the GCCS
must have operated at least 75 percent of the hours during the 12
months leading up to the Tier 4 SEM demonstration.
3. Subcategory of Closed Landfills
    Because many landfills are closed and do not produce as much LFG,
the EPA is finalizing the proposed subcategory for landfills that close
on or before September 27, 2017. Landfills in this subcategory will
continue to be subject to an NMOC emission threshold of 50 Mg/yr for
determining when controls must be installed or can be removed,
consistent with the NMOC thresholds in subparts Cc and WWW of 40 CFR
part 60. These closed landfills would also be exempt from initial
reporting requirements (i.e., initial design capacity, initial NMOC
emission rate, GCCS design plan, initial annual report, closure report,
equipment removal report, and initial performance test report),
provided that the landfill already met these requirements under
subparts Cc or WWW of 40 CFR part 60.
4. Criteria for Removing GCCS
    Landfill emissions increase as waste is added to a landfill, but
decline over time; as waste decays, a landfill produces less and less
methane and other pollutants. In the proposed Emission Guidelines (80
FR 52112), the EPA recognized that many open landfills subject to the
Emission Guidelines contain inactive areas that have experienced
declining LFG flows. Therefore, the EPA is finalizing criteria for
determining when it is appropriate to cap, remove, or decommission a
portion of the GCCS. The criteria for capping, removing, or
decommissioning

the GCCS are: (1) The landfill is closed, (2) the GCCS has operated for
at least 15 years or the landfill owner or operator can demonstrate
that the GCCS will be unable to operate for 15 years due to declining
gas flows, and (3) the calculated NMOC emission rate at the landfill is
less than 34 Mg/yr on three successive test dates. For landfills in the
closed subcategory, the NMOC emission rate threshold for removing
controls is 50 Mg/yr.
5. Excluding Non-Productive Areas From Control
    The EPA is finalizing a provision that allows the use of actual
flow data when estimating NMOC emissions for the purposes of excluding
low- or non-producing areas of the landfill from control. Owners or
operators of landfills with physically separated, closed areas may
either model NMOC emission rates, or may determine the flow rate of LFG
using actual measurements, to determine NMOC emissions. Using actual
flow measurements yields a more precise measurement of NMOC emissions
for purposes of demonstrating the closed area represents less than 1
percent of the landfills total NMOC emissions. The Emission Guidelines
historically allowed owners or operators to exclude from control areas
that are non-productive. In this final action, the retained the 1
percent criteria level, rather than raising it, to prevent landfills
from excluding areas from control unless emissions were very low. But,
to help owners or operators demonstrate that a non-productive area may
be excluded from control, the final rule allow the owner or operator to
use site-specific flow measurements to determine NMOC emissions.
6. Landfill Gas Treatment
    The EPA is finalizing two provisions related to LFG treatment.
First, the EPA is clarifying that the use of treated LFG is not limited
to use as a fuel for a stationary combustion device but also allows
other beneficial uses such as vehicle fuel, production of high-Btu gas
for pipeline injection, and use as a raw material in a chemical
manufacturing process. Second, the EPA is defining ``treated landfill
gas'' as LFG processed in a treatment system meeting the requirements
in 40 CFR part 60, subpart Cf, and defining ``treatment system'' as a
system that filters, de-waters, and compresses LFG for sale or
beneficial use. Owners or operators must develop a site-specific
treatment system monitoring plan that includes monitoring parameters
addressing all three elements of treatment (filtration, de-watering,
and compression) to ensure the treatment system is operating properly
for each intended end use of the treated LFG. They also must keep
records that demonstrate that such parameters effectively monitor
filtration, de-watering, and compression system performance necessary
for each end use of the treated LFG. The treatment system monitoring
plan must be submitted as part of the landfill's title V permit
application. The permitting authority will review the permit
application, including the treatment system monitoring plan, as part of
the general permitting process. The treatment system monitoring
parameters would be included in the permit as applicable requirements
and thus become enforceable conditions (i.e., the landfill monitors the
treatment system monitoring parameters and maintains them in the
specified range).

B. What are the monitoring, recordkeeping, and reporting requirements?

1. Wellhead Monitoring
    The operational standard, corrective action, and corresponding
recordkeeping and reporting remain for temperature and maintaining
negative pressure at the wellhead. The EPA is removing the operational
standards for nitrogen/oxygen levels at wellheads. Thus, the EPA is
removing the corresponding requirement to take corrective action for
exceedances of nitrogen/oxygen at wellheads. These adjustments to the
wellhead monitoring parameters apply to all landfills. Although
landfill owners or operators are not required to take corrective action
based on exceedances of nitrogen/oxygen levels at wellheads, they are
required to monitor nitrogen/oxygen levels at wellheads on a monthly
basis to inform any necessary adjustments to the GCCS and must maintain
records of all monthly readings. The landfill owner or operator must
make these records available to the Administrator upon request.
2. Surface Monitoring
    The EPA is finalizing the proposed requirement to monitor all
surface penetrations. Landfills must conduct SEM at all cover
penetrations and openings within the area of the landfill where waste
has been placed and a GCCS is required to be in place and operating
according to the operational standards in 40 CFR part 60, subpart Cf.
Specifically, landfill owners or operators must conduct surface
monitoring on a quarterly basis around the perimeter of the collection
area and along a pattern that traverses the landfill at no more than 30
meter intervals, at all cover penetrations, and where visual
observations may indicate the presence of elevated concentrations of
LFG, such as distressed vegetation and cracks or seeps in the cover.
Cover penetrations include wellheads, but do not include items such as
survey stakes, fencing or litter fencing, flags, signs, trees, and
utility poles.
3. Corrective Action
    The owner or operator must measure the LFG temperature at the
wellhead and gauge pressure in the gas collection header applied to
each individual well on a monthly basis. If there is an exceedance
(i.e., LFG temperature of 55 degrees Celsius (131 degrees Fahrenheit)
or positive pressure), the owner or operator must initiate corrective
action within 5 days. If the temperature exceedance or positive
pressure cannot be resolved within 15 days, then the owner or operator
must determine the appropriate corrective action by conducting a root
cause analysis and correct the exceedance as soon as practicable, but
no later than 60 days after the first measurement of the temperature
exceedance or positive pressure. For corrective action that takes
longer than 60 days to fully implement, the owner or operator must also
conduct a corrective action analysis and develop an implementation
schedule for the corrective action that does not exceed 120 days. The
owner or operator must also notify the Administrator of any corrective
action exceeding 60 days within 75 days and also include a description
of the root cause analysis, corrective action analysis and
implementation schedule in the annual report. If corrective action is
expected to take longer than 120 days after the initial exceedance, the
owner or operator must submit the corrective action plan and
corresponding implementation timeline to the Administrator for approval
within 75 days of the first measurement of positive pressure. Owners or
operators must keep records of corrective action analyses. Owners or
operators must include corrective action records in the annual
compliance report for corrective actions that take more than 60 days to
implement.
4. Update and Approval of Design Plan
    The EPA is reaffirming some requirements and revising others to
address design plans. Design plans must continue to be prepared and
approved by a professional engineer. The landfill owner or operator
must then notify the Administrator that the plan is completed and
provide a copy of the

plan's signature page. The Administrator will now have 90 days to make
a decision about whether the plan should be submitted for review. If
the Administrator chooses to review, the approval process continues at
outlined in this section. However, if the Administrator indicates that
submission is not required or doesn't respond within 90 days, the
landfill owner or operator can continue to implement the plan with the
recognition that they are proceeding at their own risk. In the event
that the design plan is required to be modified to obtain approval, the
owner/operator must take any steps necessary to conform any prior
actions to the approved design plan and any failure to do so could
result in an enforcement action.
    The EPA is also finalizing two criteria for when an affected source
must update its design plan and submit it to the Administrator for
approval. A revised design plan must be submitted on the following
timeline: (1) Within 90 days of expanding operations to an area not
covered by the previously approved design plan; and (2) prior to
installing or expanding the gas collection system in a manner other
than the one described in the previous design plan. The final rule
continues to require landfill owners or operators to prepare both an
initial and revised design plan.
5. Electronic Reporting
    The EPA is requiring owners or operators of existing MSW Landfills
to submit electronic copies of certain required performance test
reports, NMOC emission rate reports, annual reports, Tier 4 emission
rate reports, and wet landfilling practices through the EPA's Central
Data Exchange (CDX) using the Compliance and Emissions Data Reporting
Interface (CEDRI). Owners or operators are allowed to maintain
electronic copies of the records in lieu of hardcopies to satisfy
federal recordkeeping requirements.
    The requirement to submit performance test data electronically to
the EPA applies only to those performance tests conducted using test
methods that are supported by the Electronic Reporting Tool (ERT). A
listing of the pollutants and test methods supported by the ERT is
available at: www3.epa.gov/ttn/chief/ert/ert_info.html. When the EPA
adds new methods to the ERT, a notice will be sent out through the
Clearinghouse for Inventories and Emissions Factors (CHIEF) Listserv
(www.epa.gov/air-emissions-inventories/emissions-inventory-listservs)
and a notice of availability will be added to the ERT Web site. You are
encouraged to check the ERT Web site regularly for up-to-date
information on methods supported by the ERT.
    The EPA believes that the electronic submittal of the reports
addressed in this rulemaking will increase the usefulness of the data
contained in those reports, is in keeping with current trends in data
availability, will further assist in the protection of public health
and the environment and will ultimately result in less burden on the
regulated community. Electronic reporting can also eliminate paper-
based, manual processes, thereby saving time and resources, simplifying
data entry, eliminating redundancies, minimizing data reporting errors
and providing data quickly and accurately to the affected facilities,
air agencies, the EPA and the public.
    The EPA Web site that stores the submitted electronic data,
WebFIRE, will be easily accessible to everyone and will provide a user-
friendly interface that any stakeholder could access. By making the
records, data, and reports addressed in this rulemaking readily
available, the EPA, the regulated community, and the public will
benefit when the EPA conducts its CAA-required reviews. As a result of
having reports readily accessible, our ability to carry out
comprehensive reviews will be increased and achieved within a shorter
period of time.
    We anticipate fewer or less substantial information collection
requests (ICRs) in conjunction with prospective CAA-required reviews
may be needed. Under an electronic reporting system, the EPA would have
air emissions and performance test data in hand; we would not have to
collect these data from the regulated industry. The data would provide
useful information on actual emissions, types of controls in place,
locations of facilities, and other data that the EPA uses in conducting
required reviews or future assessments. We expect this to result in a
decrease in time spent by industry to respond to data collection
requests. We also expect the ICRs to contain less extensive stack
testing provisions, as we will already have stack test data
electronically. Reduced testing requirements would be a cost savings to
industry. The EPA should also be able to conduct these required reviews
more quickly. While the regulated community may benefit from a reduced
burden of ICRs, the general public benefits from the agency's ability
to provide these required reviews more quickly, resulting in increased
public health and environmental protection.
    Air agencies could benefit from more streamlined and automated
review of the electronically submitted data. Having reports and
associated data in electronic format will facilitate review through the
use of software ``search'' options, as well as the downloading and
analyzing of data in spreadsheet format. The ability to access and
review air emission report information electronically will assist air
agencies to more quickly and accurately determine compliance with the
applicable regulations, potentially allowing a faster response to
violations which could minimize harmful air emissions. This benefits
both air agencies and the general public.
    For a more thorough discussion of electronic reporting required by
this rule, see the discussion in the proposed NSPS (79 FR 41818) and
the 2015 proposed Emission Guidelines (80 FR 52127). 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, air agencies, and the EPA significant time, money, and effort
while improving the quality of emission inventories and air quality
regulations and enhancing the public's access to this important
information.
6. Landfills Recirculating Leachate or Adding Other Liquids
    In the ANPRM and proposed Emission Guidelines, the EPA solicited
input on whether additional action should be taken to address emissions
from wet landfills. As discussed in section VI.A.3 of this preamble,
there were a wide variety of perspectives provided in the public
comments, and while many commenters supported separate thresholds for
wet landfills, the EPA did not receive sufficient data to support a
separate subcategory for landfills adding leachate or other liquids. In
addition, the EPA has several other pending regulatory actions that
could affect wet landfills. Accordingly, the EPA believes it is
appropriate to further assess emissions from wet landfills prior to
taking additional action. Therefore, the EPA is finalizing electronic
reporting of additional data elements, as discussed in Section V.A.3 of
this preamble, to inform potential action on wet landfills in the
future.

C. Startup, Shutdown, and Malfunction Provisions

    The standards in 40 CFR part 60, subpart Cf, apply at all times,
including periods of startup or shutdown, and periods of malfunction.
The EPA is reaffirming the work practice standard applicable during SSM
events wherein

the landfill owner or operator is required to shut down the gas mover
system and close all valves in the collection and control system
potentially contributing to the venting of the gas to the atmosphere
within 1 hour of the collection or control system not operating. The
landfill owner or operator must also keep records and submit reports of
all periods when the collection and control device is not operating.

V. Summary of Significant Changes Since Proposal

A. Changes to Monitoring, Recordkeeping, and Reporting

1. Wellhead Monitoring
    Although the EPA is finalizing the proposed removal of wellhead
operational standards for nitrogen/oxygen, the EPA has decided to
retain the operational standards for temperature. The temperature
standards were considered to be an essential indicator for fires, as
discussed in Section VI.A.1 of this preamble.
2. Corrective Action
    We are revising the procedural requirements for correcting positive
pressure and temperature by allowing owners or operators 60 days to
correct exceedances. If the owner or operator cannot achieve negative
pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit)
by 60 days after the initial exceedance, owners or operators must
conduct a root cause analysis to identify the most appropriate
corrective action, which can include, but is not limited to, expanding
the GCCS. For corrective action that takes longer than 60 days, owners
or operators must develop an implementation schedule to complete the
corrective action as soon as practicable, but no more than 120 days
following the initial positive pressure or temperature reading.
Additionally, owners or operators must keep records of the corrective
action analysis. Owners or operators must submit the corrective action
and corresponding implementation timeline to the Administrator for
approval when implementation of the corrective action is expected to
take longer than 120 days after the initial exceedance.
    This change provides flexibility to owners or operators in
determining the appropriate remedy, as well as the timeline for
implementing the remedy.
3. Landfills Recirculating Leachate or Adding Other Liquids
    The EPA is adding additional electronic reporting requirements for
wet areas of landfills. The additional reporting applies to areas of
the landfill that have recirculated leachate within the last 10 years
and to areas where other liquids were added within the last 10 years.
    The EPA is requiring these landfills to annually report quantities
of liquids added and/or leachate recirculated. The first report will
contain historical quantities, where those data are available in on-
site records. The EPA is also requiring the landfill to report the
surface area over which the liquids are added or the leachate is
recirculated during each reporting year. The EPA is also requiring the
landfill to report the total waste disposed in the area with
recirculated leachate or added liquids as well as the annual waste
acceptance rates in those same areas. As discussed in Section VI.A.3 of
this preamble, this additional electronic reporting for wet landfills
will inform potential future action on wet landfills.
4. Portable Gas Analyzers
    We are allowing the use of portable gas composition analyzers in
conjunction with Method 3A to monitor the oxygen level at a wellhead. A
portable analyzer may be used to monitor the oxygen level at a wellhead
provided that it is calibrated and meets all QA/QC requirements
according to Method 3A. ASTM D6522-11 may be used as an alternative to
Method 3A for wellhead monitoring as long as all the quality assurance
is conducted as required by ASTM D6522-11. To use ASTM D6552-11, the
sample location must be prior to combustion.
    This change allows owners or operators to employ devices that are
commonly used in practice to measure wellhead parameters. This change
also eliminates the need for the landfill owner or operator to request
portable analyzers as an alternative, as well as the need for agency
review or approval of such requests. In addition to providing reliable
results when used properly, portable analyzers have a number of
benefits, including common use, the ability to provide additional
information on gas composition, and the ability to download data to a
spreadsheet for easy access and analysis.
5. More Precise Location Data
    The EPA is finalizing a requirement for landfills to report the
latitude and longitude coordinates of each surface emissions exceedance
(500 ppm methane or greater), as proposed, except the instrument
accuracy must be at least 4 meters instead of 3 meters. This change
will provide a more robust and long-term record of GCCS performance.
Landfill owners or operators and regulators can use locational data to
gain perspective on how the LFG collection system is functioning over
time and owners or operators will be able to track trends in GCCS
performance and cover practices to ensure a well operating system and
minimize emissions.

B. Tier 4

    The EPA is finalizing the use of Tier 4 SEM as an alternative way
of determining when a landfill must install a GCCS; however, in the
final rule, the final Tier 4 emissions threshold determination can be
used only at landfills that have modeled NMOC emissions using Tier 1 or
Tier 2 of greater than or equal to 34 Mg/yr but less than 50 Mg/yr
because the landfills NESHAP (40 CFR part 63, subpart AAAA) requires
landfills that have modeled NMOC emissions of 50 Mg/yr or greater to
install and operate a GCCS irrespective of surface emissions. If both
Tier 1 and Tier 2 indicate NMOC emissions of 50 Mg/yr or greater, Tier
4 cannot be used (a landfill need not model emissions under Tier 3
before using Tier 4). In order to verify that the landfill is eligible
for Tier 4, the EPA is finalizing a provision to require landfill
owners or operators that choose to use Tier 4 to continue to conduct
Tier 1 and Tier 2 NMOC emission rate calculations and report results in
the annual report.
    The EPA is also limiting the use of Tier 4 at landfills with a GCCS
installed. In order for a landfill with an operational GCCS to qualify
for Tier 4, the GCCS must have operated for at least 75 percent of the
12 months prior to initiating Tier 4 testing. The EPA is finalizing
reporting and recordkeeping requirements for the annual operating hours
of destruction devices in order to verify that a landfill with a GCCS
installed and opting for Tier 4 meets the GCCS criteria for having
operated the system.
    In addition, the EPA is finalizing specific requirements for the
use of Tier 4 for emission threshold determinations related to wind
speed. Since accurate measurements can be compromised in even
moderately windy conditions, the EPA is requiring the owner or operator
to use a wind barrier, similar to a funnel or other device, to minimize
surface air turbulence when onsite wind speed exceeds the limits in the
rule. Thus, when a wind barrier is used, the final rule allows the Tier
4 surface emissions demonstration to proceed when the average on-site
wind speed exceeds 4 mph, or gusts exceed 10 mph. Tier 4 measurements
cannot be conducted if the average wind speed exceeds 25

mph. Although we are aware of the use of wind barriers in the field,
the EPA intends to provide additional guidance on their use. In
addition, the owner or operator must take digital photographs of the
instrument setup, including the wind barrier. The photographs must be
time and date-stamped and taken at the first sampling location prior to
sampling and at the last sampling location after sampling at the end of
each sampling day, for the duration of the Tier 4 monitoring
demonstration. The owner or operator must maintain those photographs
per the recordkeeping requirements. Wind speed must be measured with an
on-site anemometer with a continuous recorder and data logger for the
entire duration of the monitoring event. The average wind speed must be
determined at 5-minute intervals. The gust must be determined at 3-
second intervals. Further, when taking surface measurements, the
sampling probe must be held no more than 5 centimeters above the
landfill surface (e.g., using a mechanical device such as a wheel on a
pole).
    The EPA is also finalizing reporting and recordkeeping requirements
to ensure that a GCCS is installed in a timely manner and to improve
the transparency of SEM testing. To ensure that a GCCS is installed in
a timely manner, the EPA is requiring a GCCS to be installed and
operated within 30 months of the most recent NMOC emission rate report
in which the calculated NMOC emission rate equals or exceeds 34 Mg/yr
according to Tier 2, once there is any measured concentration of
methane of 500 ppm or greater from the surface of the landfill. To
improve the transparency of SEM testing, landfill owners or operators
must notify the delegated authority 30 days prior to conducting Tier 4
tests and maintain records of all SEM monitoring data and calibrations.
In addition, landfill owners or operators must take and store digital
photographs of the instrument setup. The photographs must be time and
date-stamped and taken at the first sampling location prior to sampling
and at the last sampling location after sampling at the end of each
sampling day, for the duration of the Tier 4 monitoring demonstration.

C. Changes To Address Closed or Non-Productive Areas

1. Closed Landfill Subcategory
    The closed landfill subcategory is expanded to include those
landfills that close on or before September 27, 2017 which is 13 months
after publication of the final Emission Guidelines. This change gives
landfills that closed or are planning to close time to complete the
steps to reach closure.
2. Criteria for Removing or Decommissioning GCCS
    The GCCS can be capped or removed when a landfill owner or operator
demonstrates that (1) the landfill is closed, (2) the GCCS has operated
for at least 15 years or the landfill owner or operator can demonstrate
that the GCCS will be unable to operate for 15 years due to declining
gas flows, and (3) the calculated NMOC emission rate at the landfill is
less than 34 Mg/yr on three consecutive test dates (50 Mg/yr for the
closed landfill subcategory). The final rule does not contain a GCCS
removal criterion based on SEM.

D. Startup, Shutdown, and Malfunction Provisions

    In the 2015 Emission Guidelines proposal (80 FR 52103), the EPA
clarified that standards apply at all times, including periods of SSM.
The EPA also added requirements to estimate emissions during SSM
events. Consistent with Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir.
2008), the EPA is clarifying that the standards in the Emission
Guidelines, once implemented through an EPA-approved state plan or a
promulgated federal plan, apply at all times. In recognition of the
unique nature of landfill emissions, and consistent with the need for
standards to apply at all times, including during periods of SSM, the
EPA is reaffirming a work practice standard that applies during SSM
events. During such events, owners or operators must shut down the gas
mover system and close within 1 hour all valves in the collection and
control system contributing to the potential venting of the gas to the
atmosphere. The landfill owner or operator must also keep records and
submit reports of all periods when the collection and control device is
not operating.

E. Other Corrections and Clarifications

    The use of EPA Method 25A and Method 18 (on a limited basis, e.g.,
specific compounds like methane) are included in the final rule. Method
25A in conjunction with Method 18 (for methane) or Method 3C can be
used to determine NMOC for the outlet concentrations less than 50 ppm
NMOC as carbon.

VI. Rationale for Significant Changes Since Proposal

    After considering public comments and further analyzing the
available data, the EPA made several changes in this final rule
relative to what we proposed. A complete list of public comments
received on the proposed rule and the responses to them can be viewed
in the document ``Responses to Public Comments on EPA's Standards of
Performance for Municipal Solid Waste Landfills and Emission Guidelines
and Compliance Times for Municipal Solid Waste Landfills: Proposed
Rules'' (hereafter ``Response to Comments document''), which is
available in Docket EPA-HQ-OAR-2014-0451. This section of the preamble
summarizes comments and presents responses to those comments for only
those provisions that have changed since the 2015 proposed Emission
Guidelines.

A. Changes to Monitoring, Recordkeeping, and Reporting

1. Wellhead Monitoring
    In the 2014 proposed NSPS, the EPA requested comment on alternative
wellhead monitoring requirements, including potential exclusion from
the temperature and nitrogen/oxygen monitoring requirements, or a
reduction in the frequency of this monitoring. For example, the EPA
indicated that it could reduce the frequency of wellhead monitoring for
these three parameters (temperature and nitrogen/oxygen) from monthly
to a quarterly or semi-annual schedule. The EPA requested comments on
whether the potential exclusion should apply to a subset of landfills
or landfill areas based on beneficial use of LFG.
    In the 2015 proposed Emission Guidelines, the EPA proposed to
remove the operational standards (i.e., the requirement to meet
operating limits) for temperature and nitrogen/oxygen at the wellheads,
thus removing the corresponding requirement to take corrective action
for exceedances of these parameters. This approach was taken to
eliminate the need for owners or operators to request higher operating
values (HOVs) for these parameters, submit alternative timelines for
corrective action, or expand the GCCS to address exceeding these
wellhead standards. The EPA proposed to maintain the requirement to
monitor nitrogen/oxygen and temperature on a monthly basis, but to
remove the requirement to report exceedances from fluctuations or
variations in these parameters in the annual reports. Instead of annual
reporting, the EPA proposed that landfill owners or operators maintain
the records of this monthly monitoring on site to inform any necessary
adjustments to the GCCS and make these records available to the
Administrator upon request. The EPA proposed to maintain the
requirement to

operate the GCCS at negative pressure and in a manner that collects the
most LFG and minimizes losses of LFG through the surface of the
landfill. The EPA also requested comments on whether it should add a
requirement to monitor wellhead flow rate, or any other wellhead
monitoring parameters, that would help to ensure a well-operated GCCS
(80 FR 52138).
    Comment: Several commenters want the EPA to maintain the wellhead
operational standards, including states, industry consultants, and
environmental organizations, with one environmental organization
stating that these wellhead parameters are the only warning signal for
potential fire hazards. One state stated that the removal of the
operational standards could lead to some landfill owners or operators
not operating the GCCS in an effective manner, thus creating a
potential for increased LFG emissions through the landfill surface.
    Many other commenters supported removing the nitrogen/oxygen and
temperature operational standards, including industry, some states),
and the Small Business Association. Several commenters indicated that a
lack of response to or approval of HOV requests or alternative
timelines for corrective action, despite appropriate justification, is
a significant administrative barrier in the current Emission
Guidelines. These commenters stated that a lack of response to or
approval of HOVs results in owners or operators having to install new
wells to correct for temperature or oxygen exceedances even though such
expansion of the GCCS does not correct the exceedance and may be
contrary to a well-operated GCCS. One commenter stated that removing
the operational standards would alleviate one of the most significant
barriers to installing interim gas collection measures and would
alleviate the corresponding administrative burden of requesting HOVs.
Other commenters stated that removing the operational standards would
not only reduce administrative burden, but would also facilitate early
installation of GCCS and the use of appropriate best management