Emission Guidelines and Compliance Times for Municipal Solid Waste Landfills

Federal RegisterAug 29, 2016

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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.

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: (919) 541-3154; fax number: (919) 541-0246; email address:

ward.hillary@epa.gov.

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

Carbon dioxide

e 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

Cubic meters

Mg Megagram

Mg/yr Megagram per year

mph Miles per hour

MSW Municipal solid waste

mtCO

e 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

2.5

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-CH

Social cost of methane

SC-CO

Social cost of carbon dioxide

SEM Surface emissions monitoring

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,

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,

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).

Executive Office of the President, “The President's Climate Action Plan” June 2013.

https://www.whitehouse.gov/sites/default/files/image/president27sclimateactionplan.pdf.

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.

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

that they have issued.

“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.”

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.

See Trujillo

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

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.”).

American Trucking Ass'n

Atchison, Topeka & Santa Fe Ry.,

387 U.S. 397, 416 (1967).

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.

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.

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.”).

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,

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.

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.

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

), 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

) 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 (mtCO

e)) 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 CO

, 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 (PM

2.5

) 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 CO

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-CH

) and the average social cost of CO

(SC-CO

), each at a 3-percent discount rate, results in an estimate of about $440 million in 2025 (2012$).

The SC-CH

and SC-CO

are the monetary values of impacts associated with marginal changes in methane and CO

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 PM

2.5

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-CH

at a 3 percent discount rate, average SC-CO

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

Category

NAICS

Examples of affected facilities

Industry: Air and water resource and solid waste management

924110

Solid waste landfills.

Industry: Refuse systems—solid waste landfills

562212

Solid waste landfills.

State, local, and tribal government agencies

924110

Administration of air and water resource and solid waste management programs.

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.”

Methane is a potent greenhouse gas (GHG) that is 28-36 times greater than carbon dioxide (CO

) and has an atmospheric life of about 12 years.

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.

Executive Office of the President, “The President's Climate Action Plan” June 2013.

https://www.whitehouse.gov/sites/default/files/image/president27sclimateactionplan.pdf.

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.

The “Climate Action Plan: Strategy to Reduce Methane Emissions”

(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.

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.

The EPA recognized the climate benefits associated with reducing methane emissions from landfills nearly 25 years ago. The 1991 NSPS Background Information Document

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).

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.

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

(compared to an observed increase in methane concentrations of about 80 ppb over those 20 years).

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.

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 CO

, 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 (CO

e)).

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 CO

e. 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.

Total U.S. methane emissions were 731 teragrams (Tg) CO

e 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.

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 PM

2.5

and ozone formation. As documented in previous analyses (U.S. EPA, 2006

, 2010

, and 2014

), exposure to PM

2.5

and ozone is associated with significant public health effects. PM

2.5

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.

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).

Nearly 30 organic HAP have been identified in uncontrolled LFG, including benzene, toluene, ethyl benzene, and vinyl chloride.

Benzene is a known human carcinogen.

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.

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.

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.

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.

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.

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.

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 CO

, 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 CO

20 21

According to the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report, methane is the second leading long-lived climate forcer after CO

globally.

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.

As previously noted, this rulemaking uses the AR4 100-year GWP value for methane (25), rather than AR5, for CO

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.

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

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).

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.

“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”).

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).

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

EPA

, 684 F. 3d 102, 116-26 (D.C. Cir. 2012).

“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, CO

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.”

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.”

USGCRP, Third National Climate Assessment, p. 221.

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.

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.”

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 °C to 4.8 °C (4.7 to 8.6 °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 °C (1.8 °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.

National Research Council, Understanding Earth's Deep Past, p. 138.

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 °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 °C (1.5 °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 °C (5.4 °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.

Concentrations today are likely higher than they have been for at least the past 800,000 years.

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.

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.

Ed Dlugokencky, NOAA/ESRL (

www.esrl.noaa.gov/gmd/ccgg/trends_ch4/

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.

Blunden, J., and D. S. Arndt, Eds., 2015: State of the Climate in 2014. Bull. Amer. Meteor. Soc., 96 (7), S1-S267.

http://www.ncdc.noaa.gov/sotc/global/201513.

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.”

For example, they stated:

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 °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 °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 °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 °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 °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 °F to 9.7 °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 °F in the past 60 years. Warming in the winter has been even greater, rising by an average of 6 °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 °F in the northernmost parts of Alaska, by 8 to 10 °F in the interior, and by 6 to 8 °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 °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 °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 °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 °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 °F in the Southern Plains and more than 95 °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 °F by 2055 and 4.7 °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.

Almost half of the global annual mean ozone increase since preindustrial times is believed to be due to anthropogenic methane.

Projections of future emissions also indicate that methane is likely to be a key contributor to ozone concentrations in the future.

Unlike nitrogen oxide (NO

) 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.

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.

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/.

Ibid.

West, J.J., Fiore, A.M. 2005. “Management of tropospheric ozone by reducing methane emissions.”

Environ. Sci. Technol.

39:4685-4691.

Anenberg, S.C., et al. 2009. “Intercontinental impacts of ozone pollution on human mortality,”

Environ. Sci. & Technol.

43: 6482-6487.

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.

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.

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).

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

, 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

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 practices to maximize gas collection. Two commenters from state agencies agreed with removing the operational standards, and agreed with retaining monthly monitoring of temperature and nitrogen/oxygen and retaining the corresponding monitoring data.

Several commenters suggested that certain monitoring data should be reported on a semi-annual basis so that agencies can identify or prevent fires. For example, state agency commenters suggested that the EPA require semi-annual reporting of wellhead readings above 5 percent oxygen and 130 degrees Fahrenheit, which was supported by supplemental comments received from the industry and industry trade organizations. One commenter also suggested reporting of any subsurface fire. One regional agency wanted the results to be reported if temperature exceeds 150 °F and also suggested reporting any methane to carbon dioxide ratio less than 1.

Commenters that supported removal of the operational standards for temperature and nitrogen/oxygen also contended that the nitrogen/oxygen and temperature wellheads parameters are poor indicators of landfill fires or inhibited decomposition and that landfill owners or operators already have their own incentive to prevent landfill fires. Commenters added that expanding the LFG collection system by drilling new wells may introduce more air into the landfill, which can exacerbate a fire and actually increase oxygen content. Commenters (0451-0178, 0451-0167, 0215-0191, 0215-0121) that favored retaining the operational standards for temperature and nitrogen/oxygen contend that temperature and nitrogen/oxygen data are essential to inform regulators of the presence of the potential for a landfill fire.

Response:

After carefully considering public comments and available data, the EPA is removing the operational standards (

i.e.,

the requirement to meet operating limits) for nitrogen/oxygen, but not temperature. Landfill owners or operators must continue to monitor nitrogen/oxygen on a monthly basis, however, to ensure that the GCCS is well maintained and operated, collects the most LFG, and minimizes losses of LFG through the surface of the landfill. Landfill owners or operators must maintain records of this monthly monitoring and make these records available to the Administrator upon request. The EPA is requiring monthly monitoring and recordkeeping for these wellhead monitoring parameters (

i.e.,

oxygen, nitrogen, temperature, and pressure), since these are key indicators that are already being monitored by landfill owner or operators to determine how well the landfill is being operated, including the capturing and destroying landfill gas, promoting efficient anaerobic decomposition and/or preventing landfill fires.

Because of concerns regarding fire hazards, the EPA is retaining the operational standard for temperature. Landfill owners or operators must electronically submit, as part of their annual report, all readings that show LFG temperatures greater than 55 degrees Celsius (131 degrees Fahrenheit), and document the root cause and corrective action taken to correct for this exceedance, as discussed in section VI.A.2 of this preamble. While several commenters supported removing the temperature parameter, other commenters were concerned with fire risks if the parameter was removed. In addition, given the EPA experience with consent decrees and other enforcement actions involving elevated temperature values, the EPA has decided to retain temperature as an operating standard in the final rule. This overall approach will reduce the number of requests for higher operating values and alternative timeliness for nitrogen/oxygen parameters. In addition, note that regulatory agencies can request data records of oxygen, nitrogen, or temperature monitoring, as measured on a monthly basis, at any time.

Landfills are subject to 40 CFR part 60, subpart A. These provisions require landfill owners or operators, to the extent practicable, to maintain and operate any affected facility including associated air pollution control equipment in a manner consistent with good air pollution control practice for minimizing emissions. Due to the extreme environmental consequences of a subsurface landfill fire, these provisions obligate landfill owners or operators to take all practical steps necessary to avoid landfill fires. While this action removes requirements to meet operational standards for nitrogen/oxygen at wellheads and to make corrective actions, landfill owners or operators must continue all due diligence to ensure that the GCCS is not overdrawn, thereby creating a flammable subsurface environment.

Because the corrective action requirements for certain parameters have been retained, the EPA is reaffirming its provisions for HOVs. The HOV provisions were originally enacted to address variations in temperature between landfills and between wells. With a sufficient demonstration (

i.e.

, supporting data showing the elevated parameter does not cause fires or significantly inhibit anaerobic decomposition by killing methanogens), an HOV may be established for temperature, nitrogen, or oxygen at a particular well. The EPA encourages regulatory authorities review requests for HOVs in a timely manner and to make use of these mechanisms where

appropriate.

States may also consider HOVs when developing state plans.

The EPA asserts the importance of case specific HOV requests and approvals. However, to address concerns from HOV request reviewers and those submitting requests, an example of regulatory guidance for HOV demonstrations can be found at

http://www.epa.ohio.gov/portals/34/document/guidance/gd_1002.pdf.

2. Corrective Action

In a 1998

Federal Register

notice (63 FR 32748, June 16, 1998), the EPA amended the wellhead monitoring provisions of 40 CFR part 60, subpart WWW, to allow an alternative timeline for correcting wellhead exceedances to be submitted to the Administrator for approval. The rule change made the wellhead monitoring provisions consistent with the SEM provisions, which allow an alternative remedy and corresponding timeline for correcting an exceedance to be submitted to the Administrator for approval. The EPA noted in the 1998 preamble that any timeline extending more than 120 days must be approved by the regulating agency. Since 1998, questions have been raised about the timing of correcting wellhead exceedances and whether a landfill needs agency approval for corrective action timelines that exceed 15 calendar days but are less than the 120 days allowed for expanding the GCCS.

In the 2015 Emission Guidelines proposal, the EPA clarified its intent and outlined a corresponding timeline for correcting positive pressure at a wellhead. The EPA proposed that a landfill must submit an alternative corrective action timeline request to the Administrator for approval if the landfill cannot restore negative pressure within 15 calendar days of the initial failure to maintain negative pressure and the landfill is unable to (or does not plan to) expand the gas collection system within 120 days of the initial exceedance. The EPA explained in the preamble that it did not specify a schedule in the proposed rule language by when a landfill would need to submit alternative timeline requests because the EPA determined that investigating and determining the appropriate corrective action, as well as the schedule for implementing corrective action, would be site specific and depend on the reason for the exceedance (80 FR 52126). In addition, the EPA requested comment (80 FR 52126) on an alternative timeline that extends the requirement for notification from 15 days to as soon as practicable, but no later than 60 days from when an exceedance is identified. In the 2014 ANPRM, the EPA had requested comment on the same approach, as well as whether 60 days is the appropriate time to make necessary repairs.

Comment:

The EPA received comments on the proposed changes, including the time allowed for corrective action and for submitting alternative timeline requests for approval by the Administrator. Regarding the timeframe for submitting a request, several state agencies recommended extending the 15-day timeline for a request to be submitted and indicated that 15 days is not sufficient time to evaluate the problem and plan for corrective action, which may often involve construction activities. There were varied opinions from the state agencies on what length of time beyond 15 days is appropriate. Two agencies supported an extension to as soon as practicable but no later than 60 days, other agencies specified that the request should be submitted within 30 days from the initial exceedance.

Industry representatives from private and publicly owned landfills as well as waste industry consultants opposed the requirement to submit a request for an alternative corrective action timeline within 15 days. The commenters were concerned that 15 days is not enough time to assess the appropriate solution across miles of interconnected piping. In addition, the commenters were concerned that a 15-day time period would increase the paperwork for both the landfill and the reviewing regulatory agency. One commenter indicated that while many repairs can be completed within 60 days, some repairs, especially in cold weather climates, may take longer. One industry commenter suggested that a timeframe of 90 days to complete any adjustments or repairs is appropriate. If the corrections could not be made within 90 days, the commenter stated that the landfill would be prepared to have the system expanded within 120 days.

Industry commenters raised the issue that the timeline for corrective action for surface exceedances in the current subpart WWW regulations, 40 CFR 60.755(c)(4)(v), allows 120 days to install a new well or other collection device or submit an alternative timeline for another corrective action. These commenters also indicated that the 1998 NSPS amendments modified the corrective action for wellhead parameter exceedances to be consistent with the timeframe allowed for correcting surface exceedances (63 FR 32748, June 16, 1998). The commenters also noted that the 1998 amendments recognized that installation of a new well may not always be the appropriate corrective action for remedying a wellhead exceedance.

Despite the 1998 rule amendments, several of these industry commenters note that interpretation and implementation of the 1998 amendments to 40 CFR 60.755(a)(3) have been inconsistent, with some agencies only requiring the landfill owner or operator to submit requests if the corrective action will take longer than 120 days. Other states have taken the position that any exceedances that cannot be resolved within 15 days must automatically result in a requirement to expand the GCCS. One commenter referenced determinations that required landfills to submit an alternative timeline request within 15 days. One commenter indicated that the original rule never anticipated notification and a request for an alternative compliance timeline within 15 days, while another commenter indicated that the state of Texas requires landfills to submit alternative timelines only if the corrective action requires more than 120 days to complete.

In consideration of the 1998 final rule notice, industry commenters recommended that EPA require landfill owners or operators to submit an alternative timeline request for approval as soon as practicable and only in circumstances in which a system expansion or alternative corrective action will require more than 120 days to complete. One of the commenters (Republic 0451-0176) suggested that this approach was consistent with the Petroleum Refineries NSPS (40 CFR part 60, subpart Ja). The commenter noted that while the Landfills NSPS requires special approval to avoid the default corrective action of expanding the GCCS, the Refineries NSPS requires a root cause analysis to identify the appropriate corrective action, without specifying a default approach. The Refineries NSPS requires a root cause analysis and a corrective action analysis for exceedances and requires the facility to implement the corrective action within 45 days. If the corrective action cannot be completed in 45 days, the refinery must document and record all corrective actions completed to date. For actions not fully completed by day 45, they must develop an implementation schedule, as soon as practicable, for beginning and completing all corrective action.

One commenter provided some ideas for landfills to demonstrate good faith effort to comply with the 120-day corrective action schedule. They suggested the rules clarify that the landfill owner or operator is required to submit a notification to the agency that

identifies and describes the diagnosis performed, the results of the diagnosis, identifies the corrective measure or alternative remedy to be implemented and reason(s) why system expansion is not appropriate to correct the exceedance. Under such an approach, corrective measures other than expansion that take 0-60 days to complete from the initial exceedance would not require any notification or approval but they would be documented in the annual compliance report. For corrective actions other than expansion that take longer than 60 days but less than 120 days to complete, the landfill owner or operator would notify the regulatory agency by day 75 from the date of the initial exceedance. This would allow 45 days for the agency to review and comment, and such notification would not require agency approval so as not to delay the site from proceeding with and completing the corrective action, as long as the corrective actions are completed within the 120-day timeframe.

Industry commenters indicated that the timeline for corrective action is affected by other regulations. Two of these commenters noted that any corrective action that involves disturbing the final landfill cover could delay diagnosing the problem. All of these commenters also noted that a 60-day timeframe is problematic for landfills affected by the Asbestos NESHAP (40 CFR part 61, subpart M), which requires a 45-day notification prior to disturbing areas that may have asbestos containing material.

Response:

The EPA is retaining the corrective action requirements for temperature in addition to negative pressure. The EPA recognizes the importance of temperature as a critical indicator of landfill fires and its effect on methanogens. Further removal of the corrective action requirements for temperature could have the unintended consequence of improper operation of a GCCS which could lead to a subsurface fire. Due to the importance of this parameter, e-reporting requirements for excessive temperature have also been established to better assess landfill fires.

The need to rely on temperature in addition to pressure is also illustrated in the report titled Subsurface Heating Events at Solid Waste and Construction and Demolition Debris Landfills: Best Management Practices at

http://www.epa.state.oh.us/Portals/34/document/guidance/gd_1009.pdf

After carefully considering the comments received and evaluating the available data, the EPA is finalizing corrective action requirements that generally give owners or operators 60 days to investigate and determine the appropriate corrective action and then implement that action. The EPA has retained the requirements for temperature and positive pressure, in that if positive pressure or temperature exceedances exist, action must be initiated to correct the exceedances within 5 calendar days. This requirement has been retained to ensure the landfill takes prompt action to ensure the GCCS remains well-operated. The EPA recognizes, however, that the appropriate corrective action, as well as a schedule to implement it, is site-specific and depends on the reason for the exceedance. Therefore, for corrective action that takes longer than 60 days after the initial exceedance to implement, the EPA is providing flexibility for the landfill to determine the appropriate course of action based on a root cause analysis. Specifically, if the owner or operator cannot achieve negative pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit) at the GCCS wellhead within 15 days, then the owner or operator must conduct a root cause analysis and correct the exceedance as soon as practicable, but no later than 60 days after positive pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit) was first measured. An implementation schedule is required for exceedances that will take longer than 60 days to correct. A root cause analysis is an assessment conducted through a process of investigation to determine the primary cause, and any other contributing cause(s), of positive pressure at a wellhead or temperature above 55 degrees Celsius (131 degrees Fahrenheit). The root cause analysis and documentation of the corrective action taken to restore negative pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit) must be kept on site as a record, but they do not have to be submitted or approved.

If negative pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit) cannot be achieved within 60 days, then the owner or operator must develop an implementation schedule to complete the corrective action(s) as soon as practicable, but no more than 120 days following the positive pressure or temperature reading. The owner or operator must also notify the Administrator within 75 days. The implementation schedule, root cause analysis, and documentation of the corrective action taken to restore negative pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit) must be submitted in the facility's next annual report, but these items do not have to be approved.

If the exceedance cannot be corrected (or is not expected to be corrected) within 120 days, then the owner or operator must submit the root cause analysis, plan for corrective action to restore negative pressure or temperature of 55 degrees Celsius (131 degrees Fahrenheit), and the corresponding implementation timeline to the Administrator. The Administrator must approve the plan for corrective action and the corresponding timeline. The owner or operator must submit the proposed corrective action and timeline to the Administrator for approval as soon as practicable but no later than 75 days after the initial exceedance. Requiring approval by the Administrator for corrective action timelines that extend beyond 120 days is consistent with the corrective action timeline for surface emissions in 40 CFR 60.36f(c)(4)(v). This approach also prevents the landfill owner or operator from delaying submittals for corrective action requests until day 120. Once the negative pressure has been restored, the facility must document the corrective actions taken in the facility's next annual report.

For corrective action required to address positive pressure or temperature, the owner or operator must keep a record of the root cause analysis conducted, including a description of the recommended corrective action(s); the date for corrective action(s) already completed following the positive pressure reading and; and for action(s) not already completed within 60 days of the initial positive pressure reading, a schedule for implementation, including proposed commencement and completion dates. For corrective actions taking longer than 60 days to correct the exceedance, the owner or operator would also include in the annual report the root cause analysis, recommended corrective action(s), date corrective actions were completed, and schedule for implementing corrective actions. The owner or operator must also notify the Administrator within 75 days. For corrective actions taking longer than 120 days to correct the exceedance, the owner or operator would include, in a separate notification submitted to the Administrator for approval as soon as practicable, but no later than 75 days after the initial positive pressure or elevated temperature reading, the root cause analysis, recommended corrective action(s), date corrective actions taken to date were completed, and proposed schedule for implementing corrective actions.

3. 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 (

i.e.,

landfills that recirculate leachate or add liquids). Commenters differed on whether the EPA should require separate thresholds or different lag times for landfills that recirculate leachate or add liquids. (The lag time is the time period between when the landfill exceeds the emission rate threshold and when controls are required to be installed and started up.)

Comments:

Commenters supported more environmentally protective requirements for wet landfills and asserted that wet landfills produce more methane but actually collect less. Commenters said that the EPA should shorten the lag time for installing controls for these landfills. Other commenters opposed separate requirements for wet landfills and contended that additional requirements for wet landfills would achieve minimal emission reductions and would result in a significant additional burden for landfills that recirculate leachate. One commenter said that the EPA should focus on potential emission reductions at landfills that recirculate leachate.

Commenters also differed on what methane generation rate (k-value) should be used in the landfill Emission Guidelines for wet landfills. One commenter indicated that they have previously provided several studies on k-values for wet landfills to EPA and urged the EPA to update the emission factors for wet landfills based on this literature prior to adjusting the control requirements at landfills recirculating leachate or adding other liquids. Another commenter asked the EPA to use higher, more representative k-values, or perhaps a sensitivity analysis for a range of k-values to estimate the impacts of controlling emissions from wet landfills in the landfills Emission Guidelines.

Response:

Based on the diverse nature of the feedback provided and several other outstanding EPA actions affecting the control requirements and emission factors for wet landfills, the EPA is not creating separate emission threshold or lag time requirements for wet landfills in this action. Instead, the EPA believes it is appropriate to further assess emissions from wet landfills prior to taking additional action on control requirements or changes to the k-values. As a result, the EPA is finalizing additional electronic reporting requirements for wet landfills with a design capacity of 2.5 million Mg or greater to inform potential future action on wet landfills. The final rule is limiting reporting of these additional data to wet landfills that meet the current size threshold of 2.5 million Mg of design capacity to be consistent with the universe of landfills that are affected by the rule.

Specifically, the final Emission Guidelines require annual electronic reporting of the volume of leachate recirculated (gallons per year) and the volume of other liquids added (gallons per year), as well as the surface area over which the leachate is recirculated (or sprayed), and the surface area (acres) over which any liquids are applied. The quantity of leachate recirculated or liquids added should be based on company records or engineering estimates. The initial report will collect historical data for the 10 years preceding the initial annual reporting year, to the extent the data are available in on-site records, along with data corresponding to the initial reporting year. After the initial report, the other annual electronic reports will include only the quantities of leachate recirculated and/or added liquid and their corresponding surface areas for each the subsequent reporting year. The EPA believes many landfills, especially those operating with a Research, Development, and Demonstration (RD&D) permit, already keep records and may submit reports containing quantities of liquids added. So, the effort to track these additional data is expected to be minimal. RD&D permits are issued through Resource Conservation and Recovery Act (RCRA) subtitle D, part 258 regulations for MSW landfills. The EPA is also aware of some state rules that require reporting of leachate or added liquids outside of the Clean Air Act reporting requirements. Consolidating these data in an electronic format in a central repository can help inform how leachate or added liquids affect LFG generation and collection whether air emission standards should be adjusted for wet landfills.

The EPA is also requiring the landfill to report the total waste disposed (Mg) in the area with recirculated leachate and/or added liquids, as well as the annual waste acceptance rates (Mg/yr) in those same areas. Recognizing that the waste quantities may be tracked at the scale house entry to the landfill and not the specific cell where the liquids are added, the EPA is allowing the landfill to report data based on on-site records or engineering estimates.

The EPA is exempting landfills in the closed landfill subcategory from this wet landfill report recognizing that this information would be difficult to obtain from this subcategory of landfills, these landfills are unlikely to still be adding liquids if closed, and also because the gas generation from these landfills is on the downward side of their gas generation curve. In addition, for similar reasons the EPA is allowing owners or operators of landfills to discontinue annual reporting of the wet landfill report after the landfill has submitted its closure report.

The EPA is also aware of annual LFG collected and annual LFG generation data electronically reported to 40 CFR part 98, subpart HH, of the GHGRP and therefore the EPA is not requesting reporting of these data in this rule to avoid duplicative requests. However, the EPA may link the wet landfill practices data collected under the landfills NSPS with the annual gas collected data under subpart HH in order to inform how liquids addition affects LFG emissions. Similarly, the EPA understands that precipitation may affect gas generation. However, since precipitation data are readily available through the National Weather Service, the EPA is not requiring reporting of this parameter. Instead, the EPA will use existing electronic data already available to link up with data collected under this final rule. These additional data will be used to assess the appropriateness of potential future action on wet areas of landfills.

The Paperwork Reduction Act (PRA) requires each federal agency to obtain OMB approval before undertaking a collection of information directed to 10 or more people. The PRA applies whether a “collection of information is mandatory, voluntary, or required to obtain or retain a benefit.” The EPA believes the additional data on wet landfills will be beneficial for evaluating whether separate thresholds for wet landfills are appropriate when revising future MSW landfill standards. Because the EPA understands that many of the data elements in the wet landfill report, including quantities of leachate or other liquids added and the surface areas over which those liquids are added are tracked at a state level as part of a leachate management or RDD permit, the EPA does not anticipate these data. Additionally, the EPA is allowing landfill owners or operators to report the data elements in the wet landfill monitoring report using either engineering estimates or on-site records to minimize the burden on respondents, depending on the types of records the landfill owner/operator may keep.

This is a new rule and a new collections submitted to OMB under

EPA ICR number 2522.02. This collection is similar to collections for subpart Cc. Thus, many of the line item burden estimates in this ICR estimate are the same as the burdens submitted to OMB under ICR number 1893.06 for the most recent ICR renewal for subpart Cc.

4. Portable Gas Analyzers

Commenters on the proposed NSPS (79 FR 41796) requested that the EPA specify that portable gas composition analyzers are an acceptable alternative to Methods 3A or 3C, and noted that these devices are commonly used in practice to measure wellhead parameters and are calibrated according to the manufacturer's specifications. Currently, approvals of these analyzers are done on a case-by-case basis. Therefore, in the preamble for the proposed revisions of the Emission Guidelines (80 FR 52141), the EPA requested data or information on using a portable gas composition analyzer according to Method 3A for wellhead monitoring. The EPA also requested data on other reference methods used for calibrating these analyzers.

Comment:

Many commenters supported the use of portable gas composition analyzers and requested that the EPA specify that these analyzers may be used as an approved alternative monitoring method for well monitoring. Three state agencies indicated the use of the portable analyzers is common practice. One of these agencies stated that Method 3A and Method 3C are designed to be used in “quasi-CEMS” and/or “laboratory benchtop” situations and most landfill operators are not using this type of equipment to test wellhead LFG; instead, landfill operators are using handheld-size portable analyzers. Another state agency stated that portable gas composition analyzers (

e.g.,

Landtec GEM 2000) are a standard for conducting MSW landfill well monitoring and the analyzers provide additional information on gas composition than what the current Emission Guidelines require, which provides operators with a better understanding of the condition of the landfill. This commenter said that a primary advantage of portable gas composition analyzers, for both landfills and regulators, is that these devices take and record the monitored readings (as well as other information on gas composition that is not required to be monitored in the Emission Guidelines), which can then be downloaded into a spreadsheet and prevent landfills from making data collection mistakes. The commenter suggested that the EPA and state air pollution control agencies would benefit if the EPA were to require landfills to submit, in their semi-annual reports, all of the monitoring data recorded by portable gas composition analyzers.

One commenter stated that most portable gas composition analyzers can be used to measure the oxygen level at the wellhead and can be calibrated according to Method 3A, but are unlikely to be calibrated according to Method 3C (to measure oxygen or nitrogen levels) because such calibration requires the use of gas chromatograph equipment with a thermal conductivity detector and integrator. The commenter said that Method 3A is straightforward and does not specify a particular technology. Several commenters specifically referenced the comments from an equipment manufacturer that provided specific details on how its Landtec GEM Series portable analyzers are able to comply with each specific requirement in Method 3A, including the calibration requirements. Two of these commenters said that portable gas composition analyzers should be allowed in both the Emissions Guidelines and NSPS. Another of these commenters requested that the EPA add language to the rule to recognize that balance gas is commonly used as a surrogate for nitrogen.

With regard to the EPA's request for data on other reference methods used for calibrating portable gas composition analyzers, one commenter suggested that the EPA allow ASTM D6522 as an alternative to Method 3A because an analyzer can easily be calibrated for oxygen alone following ASTM D6522. The commenter stated that although the QA/QC procedures in ASTM D6522 are different from Method 3A, they are just as rigorous as Method 3A. The commenter stated that it has extensive data available showing portable gas composition analyzers are routinely calibrated according to ASTM Method D6522 for measuring NOx, CO, and oxygen during engine testing. This commenter also stated that any analyzer or device must be calibrated according to an EPA approved method and not just manufacturer's specifications.

Response:

The EPA appreciates the commenters providing information regarding the use of portable gas composition analyzers for landfill monitoring. Commenters provided data showing that their portable gas composition analyzers are used to monitor the oxygen level at a wellhead and are capable of meeting the calibration requirements in Method 3A. Therefore, in this action, we are clarifying the use of portable gas composition analyzers with Method 3A. A portable gas composition analyzer may be used to monitor the oxygen level at a wellhead provided that the analyzer is calibrated and meets all QA/QC according to Method 3A. Although we did not receive enough information regarding calibration methods that could be used on a portable gas composition analyzer to monitor the nitrogen level at a wellhead, any portable combustion monitor analyzer that uses gas chromatography and thermal conductivity technology may be used with Method 3C. Other technologies for the measurement of nitrogen may be used in lieu of Method 3C through the administrative alternative test method process outlined in 40 CFR 60.8(b)(2).

Regarding the suggestion to allow ASTM D6522-11 as an alternative to Method 3A, the EPA thanks the commenter for their perspective. As long as all the quality assurance is conducted as required by ASTM D6522-11, then ASTM D6522-11 may be used as an alternative to Method 3A for wellhead monitoring (prior to combustion). Examples of quality assurance required by ASTM D6522-11 include, but are not limited to: analyzers must have a linearity check, interference check, bias check using mid-level gases, stability check, and be calibrated before a test; and a calibration error check and the interference verification must be conducted after the testing has occurred. Due to a different sample matrix typically found in post-combustion gas streams as stated in the applicability of ASTM D6522-11, the interference check must be done on the oxygen measurement with the appropriate gases (

e.g.,

carbon dioxide, VOC mixture, and methane) and concentration ranges. The ASTM D6522-11 method also has calibrations before and calibration checks after testing. According to Methods 3A, 3C, and ASTM D6522-11, the data are valid only when they pass the bias check or zero and upscale calibration error check. The EPA does not believe manufacturers' specifications are rigorous enough to ensure data are of a proper quality.

5. More Precise Location Data

The EPA proposed more specific requirements for reporting the locations where measured methane surface emissions are 500 ppm above background (80 FR 52124). Specifically, the EPA proposed to require landfills to report the latitude and longitude coordinates of each SEM exceedance using an instrument with an accuracy of at least 3 meters. This includes surface methane readings above 500 ppm for landfills conducting quarterly SEM with

GCCS in place, as well as landfills that are conducting Tier 4 SEM to determine the timing of GCCS installation.

Comments:

Several commenters supported and several commenters opposed the EPA's proposed requirement to report the latitude and longitude coordinates of each methane surface emissions exceedance using an instrument with an accuracy of at least 3 meters.

Of those commenters that supported the requirement, one said that making global positioning system (GPS) coordinates of each exceedance available would assist owners or operators in determining the location and timing of exceedances relative to the GCCS components and would also assist in inspections and enforcement. This commenter added that these requirements provided important compliance monitoring assurances as well as important information to landfill owners or operators regarding their GCCS effectiveness. Other supportive commenters argued that all SEM data and GPS coordinates should be recorded, no matter whether there is an exceedance. One of these commenters, a state agency, said that the NSPS and Emission Guidelines have historically required retention of only exceedance data, but GPS data correlated with SEM readings would be an invaluable addition to the monitoring procedure. Another commenter said recording all SEM data (rather than only exceedances) was necessary to show compliance with the monitoring requirement; and by linking the methane readings with positioning data, the time required to process the data would be reduced. Commenters said that by correlating the SEM readings directly with the location of the reading, facilities and their regulators could easily gain a clear picture of how the LFG collection system was functioning and anticipate problems before they arose by tracking trends in the data.

Of the commenters that opposed the requirement that owners or operators of landfills report the latitude and longitude coordinates of each exceedance using an instrument with an accuracy of at least 3 meters, one said it was unclear why coordinate information must be reported, given that it merely adds burden for sites to co

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