Colorado air regulators will hold a three-day hearing April 15-17 on new rules designed to slash emissions of toxic pollutants known to cause cancer and other serious health problems, especially in neighborhoods already burdened by dirty air.

The pollutants — benzene, hexavalent chromium, ethylene oxide, formaldehyde and hydrogen sulfide — come from industrial sources like oil refineries and factories, according to state air-quality officials.

State computer modeling shows some Denver area low-income communities face higher lifetime cancer risks from these chemicals. Near the Suncor refinery in Commerce City, residents already suffer higher rates of breathing problems, heart disease and early death, according to community health studies and state data.

The Air Quality Control Commission is considering the changes because a 2022 state law ordered officials to reduce these toxins and focus first on the hardest-hit neighborhoods.

The proposed rules would:

• Require tighter leak checks at oil refineries to cut benzene.
• Set new limits on engines and turbines to reduce formaldehyde.
• Ban uncontrolled chrome plating that releases hexavalent chromium.
• Limit hydrogen sulfide near homes and schools in high-risk zones.

Local governments, including Denver, and environmental groups say the rules are a good start to protect public health in communities that have dealt with extra pollution for years.

The Local Government Coalition said Coloradans deserve a strong priority toxic air contaminants framework to continually work toward reductions in exposure to chemicals that cause public health issues.

Industry groups, including oil and gas companies, utilities and the Colorado Chamber of Commerce, argue the rules go too far, cost too much and overlap with existing federal requirements. They want narrower rules, more flexibility on deadlines and fewer new paperwork burdens.

The hearing will be held both in person and on Zoom. Public-comment slots are already full. The commission is expected to vote on final rules at the end of the hearing. The agenda and sign-up links can be found here.

The five pollutants were chosen after years of state studies showing they drive most of the cancer risk from air toxins in Colorado. Officials must review the rules again by 2030.

All documents and position statements are posted online at the Colorado Department of Public Health and Environment’s air-quality website.