Colorado Adopts Health-Protective Benchmarks for Priority Air Toxics

Strategic Insights -

The Colorado Air Quality Control Commission has adopted health-protective benchmarks for five priority air toxics, meeting a legislative mandate and providing science-based guidance for evaluating exposure. The benchmarks identify levels of pollutants below which adverse health effects are not expected to occur, including for children, older Coloradans, and people with existing health conditions. The new standards are based on continuous lifetime exposure with a margin of safety, considering both cancer and non-cancer risks. The Commission consulted a technical working group and evaluated how other states developed similar benchmark values.

Key Takeaways:

  • The Colorado Air Quality Control Commission has adopted health-protective benchmarks for benzene, ethylene oxide, formaldehyde, hexavalent chromium compounds, and hydrogen sulfide.
  • The benchmarks meet a requirement of the state's Public Protections from Toxic Air Contaminants Act (HB 22-1244) and give Colorado a science-based foundation for evaluating long-term exposure to priority air toxics.
  • The benchmarks consider both cancer and non-cancer risks, and are based on continuous lifetime exposure with a margin of safety.
  • The Air Pollution Control Division consulted a technical working group and evaluated how other states developed similar benchmark values.
  • The Air Pollution Control Division is seeking feedback on a related report exploring whether a permitting program could use these benchmarks to calculate risks and require actions to reduce exposure.
  • The Air Quality Control Commission will review the benchmarks and may identify additional priority air toxics every five years.
  • The new standards will be submitted to the Colorado General Assembly in December 2025, as required under HB 22-1244.

Statistics:

  • 5 priority air toxics have been identified, including benzene, ethylene oxide, formaldehyde, hexavalent chromium compounds, and hydrogen sulfide.
  • The benchmarks are based on continuous lifetime exposure with a margin of safety.
  • The Air Pollution Control Division consulted a technical working group and evaluated how other states developed similar benchmark values.
  • The report exploring a permitting program is open for feedback until October 2, 2025.

Sources:

  • Colorado Department of Public Health and Environment, Benchmarks fulfill legislative mandate and provide science-based guidance for evaluating exposure
  • Public Protections from Toxic Air Contaminants Act (HB 22-1244)