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 strategy to achieve net-zero greenhouse gas emissions by 2050.
Michael Ogletree, senior director of Colorado’s air quality programs, said, “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 stricter emission control measures for up to 32 of Colorado’s 82 municipal solid waste landfills. These sites were selected based on their waste volume and methane output. Eleven of the largest landfills are already regulated under similar federal standards, which have led to reductions in greenhouse gas emissions over the past five years.
Key aspects of Regulation 31 include lowering the threshold for required emission controls compared to federal rules, mandating biofilters at closed landfills when combustion devices are removed, increasing methane monitoring through technologies such as satellite imaging and plane sensors, and phasing out open flares in favor of enclosed systems that allow for performance testing.
In addition to targeting methane—a potent greenhouse gas—the regulation also aims to reduce other pollutants like benzene and hydrogen sulfide commonly released from landfill operations.
According to estimates from the Colorado Department of Public Health and Environment (CDPHE) Air Pollution Control Division, implementation of this standard could cut up to 12.53 million metric tons of carbon dioxide equivalent by 2050. This reduction is comparable to eliminating the carbon dioxide emissions produced by burning nearly 1.41 billion gallons of gasoline.
The development process for Regulation 31 involved more than a year of engagement with community members, environmental organizations, industry representatives, and technical experts. Input was gathered through working groups beginning in August 2024 and community meetings starting December 2024. Additional refinements were made after further discussions during rulemaking hearings between August and November 2025 before final adoption in December.
The CDPHE plans ongoing stakeholder engagement as the new requirements are implemented to ensure compliance and transparency.
For further details about these changes or opportunities for public participation regarding air quality issues in Colorado, visit the division’s landfill methane reductions web page or contact cdphe.commentsapcd@state.co.us.
