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.

House Bill 1266, passed in July, 2021, requires Colorado's manufacturing sector as a whole to reduce their emissions 20% by 2030, based on 2015 reported emissions, which will be addressed in a second phase of the GEMM rulemaking in 2022 and 2023. 

The rule applies 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 



The facilities subject to GEMM must submit a GHG Best Available Emissions Control Technology and Energy BMP Audit Plan to the Air Division for review, describing which GHG emitting equipment will be audited and who will be on the audit team. The audit plan must comply with requirements as described in the GEMM rule and be approved by the Division prior to the audit. Once the audit is completed, the facilities will submit their Audit Report to the Division for review. As they are submitted, Audit Reports will be made available to the public by using the links below, along with the Audit Plans and associated Division Approvals.

Audit Reports, Plans and Summaries are available using the links below:

EVRAZ Audit Plan Documents    

GCC Audit Plan Documents (Report Summary)

  • APCD's determination of GCC Rio Grande facility greenhouse gas best available emission control technology and energy best management practices under the GEMM rule. Per the requirements of the Air Quality Control Commission's Regulation 22, Part B, Section II.D.2. (Greenhouse Gas Emissions and Energy Management for Manufacturing or GEMM rule), the Air Pollution Control Division invites you to a public meeting. During this meeting, staff will review the Division's determination of Greenhouse Gas Best Available Control Technologies and Energy Best Management Practices for the GCC Rio Grande Cement Facility in Pueblo, Colorado. Public comments to the Air Quality Control Commission about this can be emailed to

Cemex Audit Plan Documents

Holcim Audit Plan Documents

A public comment period will open after the submission of each facility audit report to provide the public a chance to provide feedback on the report recommendations.




GEMM Rule Information:

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

GHG Emissions and Energy Management Audit Program Resources 

GEMM Auditor Selection: APCD Guidance Document 


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


There is currently a rule being developed to address additional industrial sources of greenhouse gas emission in Colorado. Learn more about the GEMM Phase 2 rule here.