Colorado proposes new rules to curb landfill methane emissions

The Colorado Department of Public Health and Environment (CDPHE) will propose a rule to the Air Quality Control Commission this year to reduce methane pollution from municipal solid waste (MSW) landfills. If approved, the rulemaking hearing will be held later in 2025. 

According to the state agency, MSW landfills are significant sources of methane. Colorado identified reducing methane pollution from landfills as a near-term action to reduce greenhouse gas emissions in the state’s Greenhouse Gas Pollution Reduction Roadmap 2.0.

In October 2024, the Colorado Air Quality Control Commission adopted changes to the state’s greenhouse gas reporting requirements that apply to municipal solid waste landfills. These updates to Regulation 22, Part A support the new landfill methane reduction requirements the division plans to propose in 2025. 

The rule expands greenhouse emissions reporting requirements for several air pollution sources across the state, including MSW landfills. More than 30 landfills that did not previously report their greenhouse gas emissions must begin reporting their emissions by March 31.

The new proposed methane reduction rule requirements would apply to MSW landfills based on the amount of waste currently in a landfill. The proposal will consider measures such as:

• a lower methane emissions threshold for requiring landfills to install gas collection and control systems (GCCS), and requiring GCCS to be installed sooner than federal requirements;
• methane monitoring requirements, including options to use alternative monitoring technologies and remote monitoring to identify large emission sources; and
• phasing out open flares to require enclosed flares for methane emissions control.

Public information meetings will be held Jan. 11 from 11 a.m. to 1 p.m. and Feb. 26 from 6-8 p.m. Interested parties can also send written comments on the landfill methane rule proposal to climatechange@state.co.us. Use the subject line, “Landfill Methane Reduction.”