Office of Environmental Health Hazard Assessment
Office of Governor Edmund G. Brown Jr.

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The Executive Office provides the direction and leadership necessary to plan, develop and administer programs and activities in OEHHA. Other functions provided by the executive office include legal support to various programs, legislative analysis and liaison, and communication and public information support.


The Administration Services Division carries out the various administrative task necessary to support the Office, including contracts and business services, human resources, fiscal services, and information technology.


Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986, was enacted as a ballot initiative in November 1986. The Proposition was intended by its authors to protect California citizens and the State's drinking water sources from chemicals known to cause cancer, birth defects or other reproductive harm, and to inform citizens about exposures to such chemicals.

Proposition 65 requires the Governor to publish, at least annually, a list of chemicals known to the state to cause cancer or reproductive toxicity. As of May 31, 2002, 742 chemicals have been listed: 475 carcinogens and 267 reproductive toxicants. The requirements imposed by Proposition 65 on persons doing business in California apply to chemicals that appear on the list. OEHHA is the lead agency for Proposition 65 implementation.

Integrated Risk Assessment Branch

The focus of the Integrated Risk Assessment Branch (IRAB) is to assess human and ecological health risk from exposure to chemicals contaminating California sites or facilities. The Branch has worked on a multimedia risk assessment process, based on existing methods and procedures, which can be used by the California Environmental Protection Agency (Cal/EPA) Boards, Departments and Office. Using this methodology, IRAB is developing a multimedia analysis process for helping the Air Resources Board evaluate new fuels proposed for use in California. IRAB is also developing guidance to be used by the Department of Toxic Substances Control (DTSC) for assessing health risks at existing or future school sites that may be contaminated with hazardous chemicals. IRAB staff are also working closely with DTSC on development of guidance for the assessment and remediation of structures used as clandestine drug laboratories. IRAB staff provide consultative services to the Regional Water Quality Control Boards (RWQCB) on health risks from exposure to hazardous materials at contaminated sites for which RWQCB staff are overseeing cleanups. IRAB staff provide similar consultative services to the Integrated Waste Management Board and provide input on a number of Board projects. In addition to these projects, IRAB hosts the Cal/EPA Environmental Protection Indicators for California Program, where all the Cal/EPA boards and departments, the Resources Agency and other state agencies provide input towards developing and maintain measures of environmental health. This compliments another IRAB activity, the Emerging Environmental Challenges Program, whose goal is to stimulate Cal/EPA Departments and Office into thinking proactively about future problems and solutions. IRAB is a participating member of the California Environmental Education Interagency Network, a consortium of state departments, boards, and commissions concerned with environmental education. To comply with Education Code 32064, IRAB develops a list of art and crafts materials "which cannot be purchased or ordered" for use in kindergarten and grades one through six. IRAB also participates in the Cal/EPA California/Baja California Border Coordinator Program to address human and environmental health issues along our common border.


The Reproductive and Cancer Hazard Assessment Branch (RCHAB) provides scientific support for all risk assessment programs within OEHHA with respect to developmental and reproductive toxicity, cancer, and ecological risks. RCHAB provides scientific support in the implementation of Proposition 65: in evaluating and listing chemicals as causing cancer or reproductive toxicity; in conducting dose-response assessments and developing safe harbor levels for listed chemicals; and in developing an annual list of chemicals in need of future testing. RCHAB develops guidelines for conducting human health and ecotoxicological risk assessments and develops risk assessment guidance for assessing the cancer risks associated with early in life exposures to carcinogens. RCHAB characterizes human and environmental health risks of complex mixtures associated with gasoline use in California.

The Cancer Toxicology and Epidemiology Unit within OEHHA's Reproductive and Cancer Hazard Assessment Branch researches and assesses the scientific literature to elucidate the health effects from early in life exposures to carcinogens. From these assessments, the team develops risk models that account for pre-and post-natal exposures and children's cancer guidelines that are protective of children's health (Health and Safety Code, Section 901).

The Cancer Toxicology and Epidemiology Unit within OEHHA's Reproductive and Cancer Hazard Assessment Branch is also responsible for characterizing the human and environmental health risks of air pollution associated with gasoline use in California. These activities are complementary to those of the Air Resources Board in their on-going efforts to identify and regulate mobile sources of air pollution. This work on the air exposure pathway for gasoline-related air pollutants is a component of the multimedia evaluation of motor vehicle fuels mandated under SB 989.


OEHHA is responsible for conducting health risk assessments of chemical contaminants found in air, including those identified as toxic air contaminants or on the list of chemicals under the Air Toxics Hot Spots Act. Assessments include development of Cancer Potency Factors to assess the cancer risk from carcinogens in air, and development of Reference Exposure Levels to assess noncancer health impacts. OEHHA has developed and updates risk assessment guidance for use in site-specific risk assessments under the Air Toxics Hot Spots program. OEHHA also makes health-based recommendations to the Air Resources Board for Ambient Air Quality Standards. Recent legislation, the Children's Environmental Health Protection Act, requires OEHHA to explicitly consider infants and children in evaluating health risks of air pollutants. OEHHA is evaluating current risk assessment methods for their adequacy to protect children.

OEHHA also conducts epidemiological investigations of the health effects of criteria air pollutants. Such investigations include the health impacts on sensitive subpopulations such as children and the elderly. For example, OEHHA is conducting an evaluation of the impacts of traffic-related pollutants on children. Specifically, the relationship between respiratory health of children and proximity of their schools to heavily traveled roadways including measured exposure to traffic-related pollutants is being analyzed.

OEHHA also evaluates health effects of chemicals commonly found in indoor air, including developing Reference Exposure Levels for use with indoor air exposure scenarios. OEHHA participates in a number of inter-Agency activities designed to evaluate indoor air quality health issues and to move California toward safer indoor air quality.

OEHHA provides health-related assistance to the Air Resources Board, air pollution control districts, local health officers and environmental health officers.


Follow this link to view the PETB group, and friends The Pesticide and Environmental Toxicology Branch (PETB) is composed of four units. The Pesticide and Food Toxicology Unit carries out risk assessment and hazard evaluation activities related to pesticides and other chemical contaminants in food and consumer products. These include evaluating chemical contamination of raw agricultural commodities, processed foods, and environmental media in cases of accidental release. Staff within the program perform activities required by legislation to review risk characterizations prepared by the Department of Pesticide Regulation (DPR) and to evaluate pesticide toxicity data in support of pesticide use and regulation in California.

The activities of the Pesticide Epidemiology Unit involve the following legislatively mandated programs: pesticide illness surveillance, epidemiological and other assistance to local health officers in the event of an outbreak of pesticide poisoning, and joint and mutual responsibility with the Department of Pesticide Regulation (DPR) to develop regulations to protect workers exposed to agriculture pesticides. OEHHA has a mandated membership on the Pesticide Registration Evaluation Committee and is represented on the Worker Safety Regulation Workgroup of DPR. The Unit also provides education and training on the recognition, management, and reporting of pesticide poisoning to health professionals and others, and provides guidelines for medical supervision and cholinesterase monitoring of agricultural pest control workers.

Risk communication activities carried out by the Unit include education for the public and for county health departments on pesticide related health issues. The Water Toxicology Unit performs major risk assessment and hazard evaluation activities relating to chemical contaminants in drinking water. These activities include developing health advisories, action levels, and public health goals for chemical substances in drinking water, and providing toxicological assistance for chemical monitoring activities for the drinking water supply. The program also provides education to the public and other governmental agencies on drinking water contamination and drinking water regulatory standards development.

The Fish and Water Quality Evaluation Unit evaluates chemical contaminants in fish and wildlife and develops fish consumption health advisories. Fish consumption advisories are published in the California Sport Fish Regulations and are part of a public communications program intended to help protect citizens, including sensitive subpopulations, against toxic chemicals. The program also directs studies of chemical contamination in marine fish and shellfish, develops fish sampling designs, and collaborates with other agencies in the mandated Coastal Fish Contamination Program.

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