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 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 from 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. 


BAECT Determination Public Meeting

The Division will host a virtual public meeting from 10:00 am to 12:00 p.m. on April 13th about its determinations of greenhouse gas best available emission control technology (BAECT) and energy best management practices for EVRAZ, Cemex, and Holcim under the GEMM rule. 

REGISTER HERE (you will receive a Zoom link after you register)


Audit Reports, Plans, and Summaries


Resubmitted GCC Report      GCC Audit Plan Documents     

Division BAECT Determination document 

The Division held a public meeting on its determination of the GCC Rio Grande facility on Thursday, February 9th from 10:00 a.m. to 11:00 a.m. via Zoom. (Recording)

The Division's determination was presented to the AQCC during the February 16th meeting, and approved by the commissioners. A recording of the meeting is available on the AQCC page here



EVRAZ Audit Report               EVRAZ Audit Plan Documents    

Supplemental Information to Audit Report



Cemex Audit Report              Cemex Audit Plan Documents

Supplemental Information to Audit Report



Holcim Audit Report              Holcim Audit Plan Documents

Supplemental Information to Audit Report





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.

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.


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