The Colorado Air Quality Control Commission has approved new health benchmarks for five toxic air pollutants: benzene, ethylene oxide, formaldehyde, hexavalent chromium compounds, and hydrogen sulfide. These standards are part of the requirements set by the state’s Public Protections from Toxic Air Contaminants Act (HB 22-1244), which mandates Colorado to establish health-based guidelines for priority air toxics.
The benchmarks define pollutant levels below which adverse health effects are not expected for all populations, including children, older adults, and those with pre-existing conditions. The approach incorporates current scientific research and input from community members as well as industry representatives.
“Colorado is meeting its legislative mandate to establish health benchmarks for priority air toxics,” said Michael Ogletree, Senior Director of State Air Quality Programs. “By using leading science and input from both communities and industry, the state has created public health benchmarks that could help guide future policy conversations while providing clarity today about exposure levels.”
These newly adopted values take into account both cancer and non-cancer risks associated with continuous lifetime exposure to these pollutants. They also include a margin of safety in their calculations. The Air Pollution Control Division consulted a technical working group during the process and considered how other states have developed similar standards.
As outlined by HB 22-1244, the adopted benchmarks will be submitted to the Colorado General Assembly in December 2025. In addition, the Air Pollution Control Division is currently accepting feedback through October 12, 2025 on a report regarding whether a permitting program could use these benchmarks to assess risks and require actions to reduce exposures if such a program is authorized by lawmakers. Both the benchmarks and this report will be presented at the January 2026 SMART Act hearings.
The commission plans to review these standards every five years and may add more substances to its list of priority air toxics in future reviews.
For further information about each pollutant’s health impacts or details on how these benchmarks were calculated, interested parties can consult rulemaking hearing materials or visit Colorado’s priority air toxics web page.
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