The Colorado Air Quality Control Commission has approved a new regulation aimed at reducing methane emissions from municipal solid waste landfills. The move is part of the state’s broader effort to reach net-zero greenhouse gas emissions by 2050.
Michael Ogletree, senior director of Colorado’s air quality programs, stated, “Colorado prides itself on sustainable regulations, and this progress reflects the extensive collaboration and commitment of our partners in advancing state climate goals. This new standard will significantly reduce methane emissions using proven technologies and climate-smart practices. Strong actions like this help address climate change while protecting our environment, public health, and state economy.”
The newly adopted Regulation 31 introduces emission control and monitoring requirements for up to 32 out of Colorado’s 82 municipal solid waste landfills. These include both active and closed sites that meet certain thresholds for waste volume or methane output. Currently, 11 large landfills in the state are already regulated under similar federal rules, which have led to lower greenhouse gas emissions over the past five years.
The regulation requires more landfills than federal standards to install gas collection systems due to a stricter emissions threshold. Closed landfills with combustion devices must add biofilters when those devices are removed. The rule also increases methane monitoring through methods such as satellite imaging and plane sensors, allowing landfill operators to use approved alternative technologies for periodic checks. Additionally, it phases out open flares in favor of enclosed ones that can be performance tested.
According to estimates from the Air Pollution Control Division at the Colorado Department of Public Health and Environment (CDPHE), these measures could reduce up to 12.53 million metric tons of carbon dioxide equivalent by 2050—comparable to eliminating the emissions from burning nearly 1.41 billion gallons of gasoline.
This regulation builds on previous rulemaking in October 2024 that expanded greenhouse gas reporting requirements for state landfills. Data collected through these efforts will help track reductions in methane over time as Regulation 31 is implemented.
Development of the rule involved input from community members, environmental organizations, industry representatives, and technical experts throughout more than a year-long process. The CDPHE held meetings with stakeholders between August 2024 and November 2025 before final adoption at a December hearing. Ongoing engagement with stakeholders is planned during implementation.
For further details about landfill methane reduction efforts in Colorado or participation opportunities related to air quality policy development, information is available on the division’s website.
