Colorado Moves to Regulate Cancer-Causing Air Toxins

State regulators propose new rules to cut emissions of industrial chemicals linked to serious illnesses

Mar. 28, 2026 at 4:20pm

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Colorado's Air Quality Control Commission is set to hold a three-day public hearing from April 15-17, 2026 to consider a sweeping package of new rules aimed at reducing emissions of five priority toxic air contaminants: benzene, ethylene oxide, formaldehyde, hexavalent chromium, and hydrogen sulfide. The proposed Regulation 30 rules would establish health-based standards and impose specific pollution controls on sources ranging from large refineries to smaller manufacturers, with the goal of protecting communities that have long borne the brunt of toxic air pollution.

Why it matters

State studies and local activists say certain lower-income neighborhoods in the Denver area face higher lifetime cancer risks due to exposure to these industrial chemicals. The new rules are designed to carry out a 2022 law requiring the state to identify and regulate priority toxic air contaminants, addressing long-standing community concerns about the health impacts of pollution from sources like the Suncor refinery in Commerce City.

The details

The proposed Regulation 30 rules would set health-based standards and impose specific pollution controls on five priority toxic air contaminants. For example, refineries would face tighter leak-detection requirements to reduce benzene emissions, while uncontrolled chrome-plating operations that release hexavalent chromium would be banned. The rules also aim to cut formaldehyde from certain engines and turbines, and cap hydrogen sulfide levels in identified high-risk zones near homes and schools.

  • The Air Quality Control Commission has scheduled a public rulemaking hearing for April 15-17, 2026 to consider the proposed Regulation 30 rules.
  • The rules are designed to carry out parts of the 2022 Public Protections From Toxic Air Contaminants law, which required the state to identify priority toxic air contaminants and adopt controls on a strict timetable.

The players

Colorado Department of Public Health and Environment

The state agency that oversees the Air Quality Control Commission and has proposed the Regulation 30 rules to regulate priority toxic air contaminants.

Air Quality Control Commission

The state regulatory body that will hold the public hearing and vote on adopting the proposed Regulation 30 rules.

Suncor

A refinery in Commerce City, Colorado that has been the subject of community concerns about elevated health issues linked to industrial emissions.

U.S. Environmental Protection Agency

The federal agency that has raised objections to portions of Suncor's air permits in recent years, underscoring local worries about refinery pollution.

Industry groups

Including oil and gas trade associations, utilities, and the Colorado Chamber of Commerce, who argue the proposed Regulation 30 rules go too far and are overly broad, expensive, and duplicative of existing federal standards.

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What they’re saying

“We must act now to protect the health of our communities that have borne the brunt of toxic air pollution for far too long.”

— Local official

“The proposed rules are overly broad, too expensive, and overlap with existing federal standards. We need more flexible timelines and less paperwork.”

— Industry representative

What’s next

If the Air Quality Control Commission adopts the new Regulation 30 rules, regulators will still have to revisit them on a multiyear review cycle, as required by the original statute. Implementing the rules will also involve updates to permits and on-the-ground monitoring that could take months or even years to fully roll out.

The takeaway

This rulemaking process highlights the ongoing tensions between public health concerns, environmental justice, and industry pushback as Colorado works to address long-standing issues of toxic air pollution in vulnerable communities. The outcome could set an important precedent for how states balance these competing priorities when it comes to regulating industrial emissions.