The California Department of Toxic Substances Control (DTSC), within the California Environmental Protection Agency, has the responsibility of managing the State's hazardous waste program to protect public health and the environment. The duties of the Human and Ecological Risk Division (HERD), formerly the Office of Scientific Affairs, include providing scientific assistance in the areas of toxicology, risk and environmental assessment, training, and guidance.
Part of this assistance and guidance is the preparation of regulations, scientific guidance documents, and recommended procedures for use by regional staff, local governmental agencies, or responsible parties and their contractors in the characterization and mitigation of hazardous waste sites and permitted facilities (also referred to as hazardous substances release sites; toxic waste sites; treatment, storage, disposal facilities).
The U.S. Environmental Protection Agency (US EPA) has published a manual that provides detailed instructions for performing human health risk assessments (Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A), Interim Final (EPA/540/1-89/002, December 1989 (HHEM)).
In addition, the US EPA Office of Solid Waste and Emergency Response (OSWER) issues directives from time to time which clarify or provide further guidance. Multimedia human health risk assessments prepared for sites or facilities over which DTSC has jurisdiction must conform to the guidance in the HHEM and OSWER directives.
This DTSC guidance manual supplements the HHEM and OSWER directives by providing recommendations on specific technical or scientific issues that may be encountered when preparing multimedia risk assessment reports for submittal and review by the DTSC.
Supplemental Guidance files are divided by chapter and may be downloaded individually. Chapters three and four have been replaced and are available in the CalTOX download area at this site as documentation for that program. Chapter six is no longer relevant and has been withdrawn from the manual. The chapter designations are maintained to minimize conflict with prior releases of the manual.