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Greenhouse Gas Emissions and Energy Management for Manufacturing in Colorado


The Colorado Air Quality Control Commission passed a regulation for a Greenhouse Gas Emissions and Energy Management for Manufacturers In Colorado (GEMM) on October 22, 2021. The rule was effective starting December 15, 2021. This rule will help Colorado achieve the economy-wide goals to reduce 2025 greenhouse gas (GHG) emissions by at least 26%, 2030 GHG emissions by at least 50%, and 2050 GHG by at least 90% compared to Colorado's GHG emissions total in 2005. 

The GEMM rule requires facilities that show through an audit process they are using GHG Best Available Control Technologies and Energy Best Management Practices to achieve an additional 5% reduction in their GHG emissions.

The rule requirements apply to four facilities in Colorado: 

  1. EVRAZ Steel Mill in Pueblo
  2. Holcim-Portland Plant in Florence
  3. GCC Rio Grande in Pueblo 
  4. Cemex Construction Materials South in Lyons 



Facilities subject to the GEMM 1 rule were required to submit a GHG Best Available Emissions Control Technology and Energy BMP Audit Plan by December 31, 2022 to the Division for review, describing which GHG emitting equipment would be audited and who would be on the audit team. After the audits were completed, the facilities submitted an Audit Report to the Division for review. After its review, the Division issued determinations in 2023 to indicate each source's compliance status and the Commission approved those determinations. 


Audit Reports, Plans, and Related Documents

GCC Rio Grande





Past Determination Public Meeting Recordings






GEMM Rule Information:

The final rule publication can be downloaded HERE and the GEMM Rule starts on page 209. 


If you have questions, please email, with GEMM in the subject line.

A related rule to address an additional 18 industrial sources of GHG emissions in Colorado was recently adopted by the Air Quality Control Commission. Learn more about the GEMM Phase 2 rule here.


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