California Air Resources Board

What you need to know: The California Air Resources Board approved updates to its Landfill Methane Regulation to enable quicker detection and repair of methane leaks at landfills, improved monitoring and reporting, public data transparency and stronger action for recurring issues. Advanced technologies, like satellite monitoring, are a key to improved methane emissions reduction in the state.  

SACRAMENTO – Working to reduce harmful emissions across all sources, the California Air Resources Board (CARB) today approved updates to its Landfill Methane Regulation (LMR) that will enable quicker detection and repair of methane leaks at landfills, improve monitoring and reporting, and facilitate stronger action for recurring issues. Methane, generated from the breakdown of waste, is a potent greenhouse gas, and landfills are the second largest source of methane in the state. 

Findings from research and the development of new technologies provided opportunities to update the regulation to improve the collection and control of methane emissions at California’s 188 landfills subject to the LMR.  

“This is another example of California’s leadership in reducing emissions and harmful climate-warming pollutants across all sources. With these updates, California will be able to more efficiently and effectively monitor methane sources to detect and remedy leaks quickly,” said CARB Chair Lauren Sanchez. “Regardless of what’s happening in Washington, CARB will press ahead on our mission following the science and using the latest research and technology to protect Californians from climate change and harmful air pollution.” 

Updates include a greater role for the use of advanced technology including satellite imaging to detect methane leaks across the landfill, and other methods suited to monitoring the active area of a landfill and other areas that are unsafe to access by foot. Emissions reductions will also come from improved gas collection system performance; more frequent monitoring and quicker resolution when a leak is detected; stronger action for recurring issues and improved reporting for enhanced transparency and oversight. The LMR updates will also reduce co-pollutants like toxic air contaminants, volatile organic compounds and odorous compounds.  

Amendments will apply to active, inactive and closed landfills operated by both public and private entities.  

In addition to CARB, landfills are regulated by federal, state, and local agencies. The LMR allows cooperative agreements between CARB and the air districts, which allow the air districts to implement and enforce the regulation and assess fees to cover costs. Currently, 22 local air districts are implementing and enforcing the LMR. 

Why it matters 

In California, municipal solid waste landfills are the second-largest source of methane emissions. Methane is produced during the break-down of organic waste in the absence of oxygen. It is a powerful greenhouse gas with a global warming potential at least 25 times that of carbon dioxide over a 100-year period. Scientists estimate that methane is responsible for up to 25% of climate change. As a short-lived climate pollutant, methane has a relatively short atmospheric lifetime of seven to 12 years. Taking action to reduce methane emissions will rapidly reduce concentrations in the atmosphere, slowing the pace of temperature rise in this decade.  

How we got here 

The LMR was first adopted in 2010 in response to the state’s Global Warming Solutions Act to reduce methane emissions from municipal solid waste landfills. The LMR requires owners and operators to install and optimally operate landfill gas collection and control systems to minimize emissions, monitor surface methane concentration and other performance parameters, repair emission exceedances and other performance issues, conduct source testing of combustion devices used to destroy methane, keep records of these actions and data, and report compliance information to CARB and local air districts.