The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency provides toxicological consultation to state and local government on possible human health and ecological risks associated with exposures to environmental contaminants at sites undergoing regulatory or voluntary cleanup.
OEHHA also develops certain health-based criteria for use at contaminated sites, specifically children-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).
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. CHHSLs were developed by OEHHA on behalf of the California Environmental Protection Agency, pursuant to Health and Safety Code Section 57008.
State law (Health and Safety Code Section 901(f)) requires OEHHA, in consultation with the appropriate entities within the California Environmental Protection Agency, to identify those chemical contaminants commonly found at school sites and determined by OEHHA to be of greatest concern based on child-specific physiological sensitivities. OEHHA is also required (Health and Safety Code Section 901(g)) to evaluate and publish, as appropriate, numerical health guidance values for these chemical contaminants. OEHHA has developed child-specific reference doses (chRDs) as numerical health guidance values for non-cancer endpoints for chemicals.