Olympia, WA – Yesterday, May 13, the Washington State Department of Ecology published its final Landfill Methane Emissions rule, a set of updated regulations mandated by House Bill 1663 and designed to reduce methane emissions from municipal solid waste landfills. The final rule means that Washington joins a growing list of states, including Oregon, California, and Maryland, in enacting landfill emissions standards stronger than the federal regulations set by the U.S. EPA for how landfills operators must monitor, capture, and control methane. Ecology estimates the new regulation will cut landfill methane emission by about 1.6 million metric tons of carbon dioxide equivalent of methane from escaping into the atmosphere every year, based on 20-year climate impacts for methane — a 38 percent reduction from reported emissions.

“The goal of this legislation we passed in 2022 was to advance a livable and thriving future for generations of Washingtonians to come,” said State Representative Davina Duerr, chief author of HB 1663. “The Department of Ecology has been a great partner, from refining the legislation to rulemaking. This is a big step forward in slashing harmful methane emissions and meeting our state’s ambitious climate goals.”

Notable improvements from federal landfill emissions standards include:

Lower thresholds for the installation of gas collection and control systems, surface emissions monitoring and technology performance requirements;

Stronger operational standards for landfill gas collection and control systems, such as requirements that more methane be destroyed efficiently before being released into the atmosphere and the development of a design plan;

Require gas component leak detection and repair;

Modest improvements to emissions monitoring practices, such as a requirement that manual surface emissions monitoring be conducted via a tighter walking pattern

“Ecology’s final rule is an important step forward, and will meaningfully reduce methane emissions,” said Heather Trim, Executive Director of Zero Waste Washington. “This rule is yet another way that Washington continues to lead on climate. We look forward to advancing even more solutions that will advance improvements to the existing waste management system, including diverting the waste in the first place.”

In December, a group of environmental and public interest advocates released a letter to Ecology raising concerns with the draft rule language for not adequately embracing available technologies and practices to monitor and control landfill methane. The letter noted repeated instances of Washington landfills exceeding the federal limit for methane emissions, evidence of inadequate landfill management standards in need of major improvements.

The final rule fails to include some improvements that advocates suggested. There is no mandate that gas collection systems be installed early enough to capture gas that is generated quickly. EPA's recent research found food waste is decaying quicker than gas collection systems have been required.

Also missing in the rule are requirements that landfill operators use available remote sensing technology to monitor methane emissions. Instead, Washington will continue to rely on human-based monitoring, while even the White House, in its national monitoring strategy, acknowledges that on-ground surface emissions measurements alone are insufficient.

EPA has the authority to make both changes at the federal level through its Clean Air Act landfill regulations, which the agency is required to review by this August.

“Landfill pollution is an urgent climate and public health crisis, and I’m glad to see Washington take action to put in place more effective standards for landfills than the federal government,” said Katherine Blauvelt, circular economy director at Industrious Labs. “Now, we need federal regulators at the EPA to close the remaining gaps by implementing common-sense solutions such as requiring more advanced and comprehensive monitoring and earlier installation of gas collection pipes. Reducing methane is the most impactful thing we can do to slow climate change right now, and landfills are an enormous, but untapped, opportunity to do exactly that.”

Landfills are the largest source of industrial methane in Washington, emitting methane equivalent to an estimated 4.2 million metric tons of carbon dioxide (based on 20-year global warming impact), equal to 1 million cars on the road for a year. Mounting evidence shows that methane releases from landfills across the nation may be worse than had been previously thought. Recent studies published in Science and Atmospheric Chemistry and Physics reveal that landfill gas emission estimates, which are based on modeling, are set too low.  In addition to methane, landfills can leak leachate and other toxic pollutants harmful to the health of nearby communities, including carcinogens like benzene and toluene.

Other states are strengthening their landfill emissions regulations. In Michigan, landfills are required to monitor for water build up in wells and conduct monitoring for methane exceedances within just 180 days of waste being placed. The California Air Resource Board (CARB) is considering updates to its 2010 Landfill Methane Rule, with Colorado also poised to improve state regulations.

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