New EPA Air Emissions Rules Mean Greater Compliance Burden for Landfill Owners

The United States Environmental Protection Agency (EPA) recently released two rules updating the regulation of air emissions from municipal solid waste landfills. These rules enlarge the potential universe of landfills required to implement emissions controls, provide a new testing method for determining when such controls must be installed, and clarify certain definitions and procedures of the older rules. Landfill owners should be prepared to shoulder a greater compliance burden and remain aware of how these new regulations are being implemented in their respective states.


EPA’s new rules update the Clean Air Act regulations applicable to new and existing landfills that were promulgated in 1996. The rule for existing landfills updates Emission Guidelines that generally become applicable through state implementation plans under section 111(d) of the Clean Air Act. The other rule regulates “new” landfills under the New Source Performance Standards (NSPS) program, specifically, those landfills that commenced construction, reconstruction, or modification after July 17, 2014, under Clean Air Act section 111(b). The rules themselves are nearly identical in substance but may be implemented in a different manner depending on the state. As of August 1, the rules have not yet been published in the Federal Register, so the 60-day time period to challenge them in the D.C. Circuit has not begun to run.

EPA Lowers the Emissions Threshold for When Landfills Must Install Controls

Under the old NSPS and Emission Guidelines, EPA required the installation of controls in the form of a gas collection and control system (GCCS) at any landfill that met both a design capacity threshold and an emissions threshold. The design capacity threshold has not changed with these new rules – it is 2.5 million megagrams by mass and 2.5 million cubic meters by volume. 

The emission threshold has, however, been lowered. The previous threshold was set at 50 Mg/yr of non-methane organic compounds (NMOCs), a surrogate representing overall emissions of landfill gas. The new threshold is set at 34 Mg/yr of NMOCs under both the Emission Guidelines and the NSPS. 

EPA Adopts a New “Tier 4” Surface Emissions Testing Methodology

EPA is also finalizing a new emissions calculation methodology called “Tier 4” for determining when a GCCS needs to be installed at a landfill. Landfills that meet the design capacity threshold are required to calculate their projected NMOC emissions according to methods known as “tiers” within the regulations. Generally, a landfill owner starts at Tier 1, and if emissions are not projected above the emissions threshold under that method, GCCS need not be installed. If the emissions threshold is met or exceeded at Tier 1, the landfill owner may move on to the next tier or elect to install controls. If at the next tier the emissions threshold is not met or exceeded, the landfill owner is not required to install controls. The new Tier 4 method is unique in that, instead of relying on emissions projections of NMOCs like Tiers 1-3, the Tier 4 method will use surface emissions monitoring with a trigger to install controls once a 500 ppm of methane threshold is reached or exceeded. Landfills that exceed the 34 Mg/yr NMOC threshold under the earlier tiers (with an option to skip to Tier 3) will be able to avoid installing GCCS if surface emissions of methane are below 500 ppm for four consecutive quarters using Tier 4. Importantly, landfills with modeled emissions of NMOCs exceeding 50 Mg/yr will not be able to use the Tier 4 methodology under the new rules. 

EPA Creates a Subcategory for “Closed Landfills” and Eases the Burden to Remove, Exclude, and Cease Controls

In an effort to protect certain landfills that are already on the downswing, EPA includes within the final Emission Guidelines a new subcategory for closed landfills. Those landfills that close within thirteen months of the rule’s publication in the Federal Register will remain subject to the more favorable 50 Mg/yr threshold for determining when controls may be removed. These landfills will also be exempt from certain initial reporting requirements. 

EPA further eases some of the burden for removing GCCS from a closed landfill. One of the requirements to qualify for GCCS removal under the old regulations was that the landfill had to have operated the GCCS for 15 years. EPA is now allowing landfills to demonstrate that it would be impossible to operate the GCCS for 15 years due to declining gas flows to satisfy this requirement. A closed landfill owner looking to remove controls must also show that emissions from the landfill do not meet or exceed the 34 Mg/yr NMOC threshold in three successive emissions tests. 

Landfill owners looking to exclude areas from control, or cease control where a GCCS is already installed, may now use actual gas flow data to calculate whether they qualify. Use of actual gas flow data is, however, limited to testing areas that are physically separated, e.g. lined off, from other parts of the landfill. All areas where controls are excluded or have ceased must account for less than one percent of a landfill’s total NMOC emissions. 

EPA Adjusts Startup, Shutdown, and Malfunction Periods Provisions

The previous NSPS contained an exemption from its provisions during periods of startup, shutdown, or malfunction (SSM). This exemption was limited to no longer than five days for collection systems and no longer than one hour for control devices. EPA does away with this provision in the new rules, instead providing that the standards will apply at all times, including SSM periods. EPA reasons that this conclusion is consistent with the opinion of the D.C. Circuit in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) that vacated an EPA created SSM exemption under the general Part 63 regulations promulgated under section 112 of the Clean Air Act. In doing so, EPA rejects industry arguments that Sierra Club does not require this result, that the decision is only applicable to numerical emissions limitations, and that it does not fit well with the standards applicable to landfills. Instead of an SSM exemption, EPA sets forth a work practice standard that will apply during SSM events. This standard requires that the gas mover system be shut down and that all vents associated with the collection and control devices that may release gas to the atmosphere be closed within an hour of the collection or control system ceasing operation.

EPA Expands Surface Emissions Monitoring

Landfills that are required to install a GCCS must monitor surface emissions. Further increasing the compliance burden of both existing and new landfills, EPA finalizes a requirement that surface emissions testing include testing of any surface openings and cover penetrations where waste has been placed and a gas collection system is required to be operating. Although EPA did not define what may be considered a cover penetration or opening within the finalized rules, it did state in the rule preambles that such penetration would include a wellhead, but not things such as stakes or fencing. The requirement further includes monitoring of areas that appear to be subject to elevated levels of landfill gas, such as cover cracks or distressed vegetation.

EPA Reduces Required Corrective Actions and Clarifies Corrective Action Procedures

Wellheads within a GCCS are subject to operational standards which require the monitoring of certain parameters and for corrective action to be taken when exceedances are observed. EPA removes the operational requirements for wellheads related to nitrogen and oxygen, but still requires monitoring of these parameters. Due to confusion regarding the procedures required when taking corrective actions related to the remaining operational requirements for temperature and negative pressure, EPA provides some much-needed clarification. Generally, exceedances of temperature or reading of positive pressure will result in a requirement to take corrective action within five days. If the problem cannot be resolved within fifteen days, then the landfill must conduct a “root cause analysis” to determine the proper means to solve the problem and execute that solution within sixty days. If sixty days is not enough time, then the landfill will have to conduct a “corrective action analysis” and design an implementation schedule not to exceed 120 days. Those taking longer than sixty days but less than 120 will only require notification and a description of the required analyses and schedule. Fixes that are to take longer than 120 days will require the approval of the corrective action plan and timeline by the Administrator of either EPA or the relevant state implementing the standards. Record retention requirements are also applicable to these analyses and corrective actions. 

EPA Refuses to Promulgate Separate Thresholds for “Wet” Landfills

During the rulemaking process, EPA requested information on whether separate thresholds, if any, should apply to wet landfills. While EPA has had some difficulty pinning down what exactly makes a landfill “wet,” it has considered the topic in previous stages of the rulemaking in terms of the precipitation received at the landfill and whether the landfill engages in leachate recirculation or adds liquids to the landfill. EPA expressed concern that such landfills may have the capacity to emit large amounts of landfill gas over a shorter period because wet wastes decompose faster than dry wastes. EPA thus requested input whether a reduced design threshold and shorter timelines to install or expand a GCCS at wet landfills would be appropriate. Environmental groups encouraged EPA to reduce thresholds and to shorten the amount of time allowed to install or expand a GCCS for these “wet” landfills. Industry groups opposed reduced thresholds and shorter GCCS installation or expansion schedules, reasoning that such requirements would have little to no additional environmental benefit, that any effort to further regulate such landfills should be made in tandem with other regulations applicable to certain wet landfills, such as the National Emissions Standards for Hazardous Air Pollutants program provisions applicable to those landfills that add liquids, and that EPA generally lacked sufficient information to impose different requirements on wet landfills.

For purposes of compliance with the new rules, EPA limits its consideration of wet landfills to those that add liquid or engage in leachate recirculation practices. EPA indicates that it does not have sufficient information to impose any stricter thresholds and may, in fact, have other regulatory measures in the making that may affect such landfills. Landfill owners that have employed practices such as recirculating leachate or applying liquids within the past ten years under a Research, Development, and Demonstration permit issued pursuant to the Resource Conservation and Recovery Act will, however, be required to submit certain reports, provided that the landfill meets the design capacity threshold. These reports require information regarding the number of liquids or leachate used and the areas of the landfill to which the liquids are applied or leachate is recirculated, as well as amounts of waste disposed and acceptance rates of these areas. The first of these annual reports will be required to include a historical accounting of liquid use at the landfill going back ten years based on available on-site data. EPA plans on using this data, along with precipitation information from the National Weather Service, to inform what, if any, additional regulatory requirements should be imposed on wet landfills. 

EPA Updates Design Plan Procedures

The Administrator (of either EPA or the relevant state air program) will now have 90 days to act on new and revised gas collection and control system design plans. The final rules, however, place the risk on the landfill if the Administrator does not act within 90 days and the landfill wishes to proceed with the plan. If the Administrator decides that modifications to the plan are required even after the 90-day mark, the landfill will be required to implement such modifications or risk enforcement action. 

EPA Clarifies Landfill Gas Treatment and Provides Monitoring Plan Procedures

In the new rules, EPA defines treated landfill gas as that which is treated in a treatment system, and defines “treatment system” as a “system that filters, de-waters, and compresses landfill gas for sale or beneficial use.” EPA clarifies that the beneficial use for such treated gases is not limited to stationary source combustion devices, but that other beneficial uses such as vehicle fuel, gas for pipeline injection, or for use in chemical manufacturing process may be employed. EPA did not expressly limit the beneficial use of landfill gas to these examples, but they should be used as a guide for what end uses may be deemed acceptable. The final rules also require the creation of a site-specific treatment system monitoring plan (for those implementing this compliance option) that would account for the parameters necessary to ensure that the gas is treated in a manner consistent with its intended end use for each stage of treatment. EPA further does not require that these monitoring plans be submitted for Administrator approval but has expressed through the preambles to the rules that these plans would become enforceable provisions of the landfill’s Title V permit. 


In sum, EPA has increased the stringency of regulatory requirements for landfill owners and operators, while introducing greater flexibility in certain areas of the program. EPA has also given some insight that it may be contemplating different standards for “wet” landfills in future regulations by requiring these entities to submit information expressly for the purpose of informing possible future actions by EPA. Landfill owners will have to pay particular attention to their state’s regulatory docket to see how the Emission Guidelines will be implemented and whether their state is seeking to impose more stringent requirements than those set forth in either of EPA’s rulemakings.