Risk assessments at contaminated sites

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency provides risk assessment support and toxicological consultation to state and local government on human health and ecological risks associated with exposures to environmental contaminants at sites undergoing regulatory or voluntary cleanup.

As part of its efforts related to contaminated sites, OEHHA developed child-specific health guidance values for assessing risk at proposed or existing California school sites, and soil and soil-gas screening levels (also known as California Human Health Screening Levels or CHHSLs).

Fact Sheets for Contaminated Sites

• Cancer Risk and Noncancer Hazard Index
• Trichloroethylene (TCE) in Indoor Air
• Tetrachloroethylene (PCE) in Indoor Air: English | Spanish | Simplified Chinese | Vietnamese | Korean

Child-Specific Reference Doses

Child-specific reference doses are numerical health guidance values developed by the OEHHA pursuant to Health and Safety Code Sections 901(f) and 901(g)

California Human Health Screening Levels (CHHSLs)

For informational purposes only. CHHSLs have not been updated since 2010. For chemical-specific screening levels for use in assessing contaminated sites, please refer to HHRA Note 3 (DTSC HERO)

California Human Health Screening Levels (CHHSLs) are concentrations of chemicals in soil or soil gas below thresholds of concern for risk to human health—that is, an excess lifetime cancer risk of one-in-a-million (10^-6) and a hazard quotient of 1 for non-cancer health effects.

Additional resources for risk assessments at contaminates sites:

• Department of Toxic Substances Control: Human and Ecological Risk Office
  State guidance and resources for assessing human health and ecological risks
• State Water Resources Control Board: Vapor Intrusion
  Basic information and guidance documents on vapor intrusion
• Geotracker
  The State Water Resources Control Board’s data management system for tracking cleanup, permitting, enforcement, and investigation efforts at sites with contamination in the soil or groundwater
• The US Environmental Protection Agency’s Superfund Risk Assessment and Risk Assessment Guidance for Superfund (RAGS)
  National guidance, tools and databases useful for preparing human health and ecological risk assessments