EPA Underestimates Greenhouse Gas Emissions from US Landfills by at Least 25 Percent

Environmental Groups File Notice of Intent to Sue EPA Over Undercounting of Greenhouse Gases from Waste Dumps

. — Three environmental groups today announced their intention to sue EPA for failing to update its methods for estimating emissions of greenhouse gases and other air pollutants from landfills across the U.S., despite the agency’s conclusion in 2008 that the current methods underestimate emissions by at least 25 percent.

The Environmental Integrity Project, Chesapeake Climate Action Network, and Sierra Club filed their notice of intent to sue EPA under the Clean Air Act, which requires the agency to review and, if necessary, revise its emissions calculation methods every three years.

According to EPA’s estimates for 2019, the rotting of discarded food and other household waste at municipal waste landfills emitted about 4.38 million tons of methane – a potent greenhouse gas that is 86 times more powerful at warming the climate than carbon dioxide over a 20-year period. Based on the agency’s current estimation methods, landfills are responsible for about 15 percent of human-caused methane emissions in the U.S., second only to the natural gas and agricultural industries.

“When it comes to pollution, it’s very difficult to manage what you can’t measure,” said Ryan Maher, Attorney for the Environmental Integrity Project. “EPA needs to fix how it estimates emissions from this massive source of methane and other air pollutants–not only to help us understand the full extent of the landfills problem, but also to make sure that we’re holding polluters accountable and regulating these facilities properly.”

Jane Williams, Chair of the Sierra Club’s National Clean Air Team, said:  “In environmental justice communities that host landfills, their emissions are often the largest source of local air pollution. Landfills emit not only methane, but also nitrogen oxides and volatile organic compounds – and this legal action will help inform the public about how much of these pollutants they are being exposed to.”

Anne Havemann, General Counsel with the Chesapeake Climate Action Network, said: “The world’s leading scientists recently concluded that climate change poses a ‘code red for humanity. Among the easiest and most consequential actions we can take is to limit methane emissions from large sources such as landfills. EPA must update its methods so that regulators can fully understand and better regulate the climate and other air pollutants coming from landfills.”

There are as many as 2,000 municipal waste landfills operating in the U.S. today, and an additional 3,200 that have closed since 1980 but may still produce gas. Currently, an estimated 850 of these landfills are subject to EPA regulations that require emission controls, such as the burning or converting into energy of the methane produced by the decay of household waste.

However, this number of regulated landfills will likely increase—requiring more landfills with pollution control systems — if the current methods are revised and updated to reflect increased emissions estimates.  This is because EPA regulations require landfill gas collection and control systems only for the larger sources of emissions.

Back in 2008, EPA last evaluated its methods for estimating emissions from municipal waste landfills. This assessment culminated in a conclusion that the existing EPA equations and values should be revised, partly because they underestimate emissions of methane and other air pollutants from landfills by at least 25 percent. The agency recognized that the current methods failed to account for the well-established fact that gas collection systems at landfills do not collect gas produced by the landfill with 100 percent efficiency, but instead collect about 75 percent of the gas that is generated or less.

EPA released a draft of its updated methods to the public for comment in May 2009. However, it failed to take further action and the updated methods were neither finalized nor implemented.

The environmental groups are urging EPA to update and revise its emissions methods for estimating greenhouse gases and other air pollutants (including volatile organic compounds and carbon monoxide) from landfills, using the 2008 EPA assessment as an example of why the current methods are inaccurate.  Very few landfills actually measure how much methane rises from trash heaps, so formulas and estimates are used by EPA and the states as a substitute.

The environmental organizations are also challenging EPA’s failure to develop methods for estimating nitrous oxide emissions from landfills. While landfills emit only small amounts of nitrous oxide, it is even more potent than methane as a greenhouse gas, with a warming effect that is 298 times greater than that of carbon dioxide.

For a copy of the notice of intent to sue EPA, click here.  Under the federal Clean Air Act, plaintiffs are required to file a notice of intent to sue at least 60 days before they file a lawsuit.

In June 2021, the Environmental Integrity Project released a report that concluded that Maryland had been underestimating the amount of greenhouse gases released by its municipal waste landfills by a factor of four – and that annual emissions were about 51,500 tons per year, not 12,500 tons. The Maryland Department of the Environment responded by correcting its estimation methods and updating its greenhouse gas inventory with a much larger total.

The Environmental Integrity Project is a 19-year-old nonprofit organization, based in Washington D.C. and Austin, Texas, that is dedicated to enforcing environmental laws and strengthening policies to protect public health and the environment.

The Sierra Club’s mission is to explore, enjoy, and protect the wild places of the earth; to practice and promote the responsible use of the earth’s ecosystems and resources; to educate and enlist humanity to protect and restore the quality of the natural and human environment; and to use all lawful means to carry out these objectives.

The Chesapeake Climate Action Network is the largest and oldest grassroots organization dedicated exclusively to fighting for bold and just solutions to climate change in the Chesapeake region of Maryland, Virginia, and Washington, DC.