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Colorado's Proposed Rules for Air Permits in Disproportionately Impacted Communities

Chris Colclasure of Beatty & Wozniak, P.C. provided a comprehensive summary of these proposed rules in a presentation to the Rocky Mountain EHS Peer Group in January 2023.

In an effort to address environmental justice concerns, the Colorado Air Quality Control Commission (AQCC) is revising Regulation No. 3, Stationary Source Permitting, as mandated by HB 21-1266, the Environmental Justice Act. With a hearing scheduled for May 16-19, 2023, the proposed changes to air permitting rules will impact facilities operating in disproportionately impacted (DI) communities. This blog post outlines the key aspects of the proposed rules and their implications for businesses in Colorado.

Identifying Disproportionately Impacted Communities

The AQCC is required to adopt new rules by June 1, 2023, which include identifying DI communities and revisiting the listing at least every three years. Affected pollutants include VOCs, NOx, fine PM, BTEX, and other HAPs identified by the AQCC. The AQCC may set applicability thresholds, and the rules must provide for enhanced modeling and monitoring requirements for new and modified sources of affected pollutants in DI communities.

Requirements Based on EnviroScreen Score

Colorado's EnviroScreen EJ Mapping Tool is used to identify DI communities, and permit application requirements will vary depending on a facility's EnviroScreen score.

New Components of Permit Applications

Starting July 15, 2023, permit applications must include an Environmental Justice (EJ) summary, containing information on emissions of affected pollutants, location within or outside a DI community, EnviroScreen score and data, and EJ considerations. Additionally, sources that commence construction or modify on or after July 15, 2023, in a DI community must apply Reasonably Available Control Technology (RACT) for VOCs, NOx, and fine PM. The APCD also encourages consideration of BTEX.

Enhanced Modeling

For sources new or modified on or after July 15, 2023, in all DI communities, the APCD will require enhanced modeling as appropriate; however, the term "enhanced modeling" remains undefined. Stakeholder meetings have suggested using a more stringent 1-hour NOx emissions rate threshold to trigger modeling, and the Economic Impact Analysis suggests that current modeling requirements may be sufficient.

Enhanced Monitoring

The APCD will include requirements for enhanced monitoring of sources of affected pollutants that commence construction or are modified on or after July 15, 2024. The proposal specifies that facilities with an EnviroScreen score greater than 80% must conduct enhanced monitoring or pay a fee for community monitoring. Those with a score equal to or less than 80% must pay a fee for community monitoring. The APCD will also convene a panel of monitoring experts to develop guidelines, and Title V renewal permits may add monitoring requirements.

Initial Reaction to Proposal

The proposal does not establish or change ambient concentration thresholds and does not prohibit permits. However, it imposes new obligations on facilities and grants broad discretion to the APCD. Consequently, facilities may want to collect data to defend their operations.

AQCC Hearing Timeline and Related Initiatives

The AQCC hearing will take place on May 16-19, 2023. Party status requests were due by early February, with written public comments due by early May. Verbal public comments will be accepted.

These proposed rules are part of a broader initiative by the CDPHE to address air quality and environmental justice issues, including fenceline and community monitoring (HB 21-1189), toxic air contaminants (HB 22-1244), and collaboration between CDPHE, COGCC, and local government monitoring.


The proposed changes to Colorado's air permitting rules will have a significant impact on businesses operating in DI communities. It is essential for companies to understand these new requirements and obligations to ensure compliance and minimize potential risks. Stay informed by attending the upcoming AQCC hearing and participating in the public comment process.


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