California Office of Environmental Health Hazard Assessment

California Office of Environmental Health Hazard Assessment

Logo of OEHHA
Agency overview
Headquarters	Cal/EPA Building, Sacramento, California United States
Employees	120 staff
Annual budget	$17.5 mil total; $8.3 mil general fund
Agency executive	Kris Thayer, PhD, Director
Parent agency	California Environmental Protection Agency
Website	http://www.oehha.ca.gov

The Office of Environmental Health Hazard Assessment, commonly referred to as OEHHA (pronounced oh-EEE-ha), is a specialized department within the cabinet-level California Environmental Protection Agency (CalEPA). OEHHA is the lead state agency for the assessment of health risks posed by environmental contaminants.

As the scientific adviser within CalEPA, OEHHA's work assists decision makers within CalEPA, the California Department of Public Health, and other agencies and non-governmental organizations (see below). This includes assessing health and environmental risks from:

• Carcinogens
• Reproductive toxins
• Air pollutants
• Pesticides
• Chemical contaminants in food and water
• Chemical exposures in the workplace
• Climate change in California

OEHHA's current director is Dr. Kris Thayer, who was appointed by Governor Gavin Newsom on April 29, 2025. Previously, Dr. Lauren Zeise directed OEHHA from 2015 until 2024.

Goals and responsibilities

OEHHA's goals as a governmental agency include:

• Improve the quality of the public's health and the environment.
• Advance the science for the evaluation of risks posed to the public health and environment, and provide risk assessment leadership for the State of California.
• Provide high quality information about environmental health hazards to the public.

Scientific responsibilities

OEHHA assesses the risk of environmental chemicals based on health considerations alone. In contrast, risk managers consider economic and technical feasibility as factors in their decisions. This separation is essential to prevent undue political influence on the evaluation of health risks. These factors are and should remain explicitly excluded from the assessment of risk. OEHHA plays a critical and unique role that allows for the separation of risk assessment and hazard evaluation from risk management with primary goal of protecting public health and the environment.

OEHHA's Top Ten

OEHHA' most recognizable contributions to public and environmental health are:

1. OEHHA's groundbreaking work that showed that chromium in drinking water causes cancer; this issue was publicized in the movie Erin Brockovich.
2. OEHHA's research was critical in passing legislation to ban toxic phthalates from children's toys in California.
3. OEHHA was the first agency to identify second-hand tobacco smoke as a causal factor in breast cancer in young women.
4. California's ban on two widely used toxic flame retardants was supported by OEHHA's research. The California ban led to these chemicals being phased out in the United States.
5. In the face of strong opposition, OEHHA was the first government agency to establish that diesel exhaust causes cancer and induces asthma in children. OEHHA's work has led to stringent new controls on this widespread pollutant.
6. OEHHA has compiled the most comprehensive list in the world of chemicals that cause cancer, infertility, birth defects (known as the Proposition 65 list). Governments throughout the world rely on this list to regulate toxic chemicals. Manufacturers of consumer products use the list to design safer consumer products.
7. With OEHHA's ongoing support, the California Attorney General has led the way in removing lead from consumer product' including venetian blinds, children's toys and jewelry, tableware, water faucets and ceramics. Other California success stories include reducing the use of toxic pesticides in flea collars and no-pest strips and removal of a cancer-causing chemical from office supplies.
8. OEHHA maintains a list of hazardous arts and crafts supplies that contain toxic substances which pose health dangers to children. California elementary schools are prohibited from purchasing these materials. OEHHA also provides advice on the selection and use of safer art supplies.
9. OEHHA's research contributed to the phase-out of a toxic gasoline additive (MTBE) that contaminated groundwater throughout California.
10. California was the first state to regulate a rocket fuel component which widely contaminates drinking water and produce including lettuce. OEHHA's research provided the basis for this drinking water standard.

Traditional roles

OEHHA's work products cover a variety of environmental media. Traditionally OEHHA has focused on four primary areas:

Air pollution

• Health-based air quality standards for pollutants associated with smog
• Health effects assessments for toxic air contaminants
• List of toxic air contaminants that disproportionately impact children
• Indoor air guidelines for green building

Water pollution

• Fish consumption advisories including warnings for pregnant women and children
• Health protective levels for contaminants found in drinking water

Proposition 65: Carcinogens and Reproductive Toxicants

Main article: California Proposition 65 (1986)

• Maintain Proposition 65 list of chemicals known to be carcinogens and reproductive toxicants
• Health-based assessments of safe levels for Proposition 65 carcinogens and reproductive toxicants

Multimedia risk assessment

• Assess human and ecological health risk from exposure to chemicals contaminating California sites or facilities
• Multimedia evaluation of the health effects of fuels

More recently

In recent years OEHHA has taken on new mandates to address emerging environmental issues of particular concern to the California public:

• Biomonitoring – Evaluation of priority chemicals for Biomonitoring in California
• Green Chemistry – Identification of key hazards of chemicals for implementation of green chemistry laws
• Occupational health – Advice on health-based occupational exposure limits
• Dry Cleaning – Research on safer alternative methods for dry cleaning
• Environmental Justice
• Cumulative Impacts
• Emergency response for release of hazardous chemicals
• Evaluation of contamination from oil spills
• Evaluation of chemical sprays used to control invasive species
• Child-specific health-based reference doses used to evaluate toxic chemicals found at school sites
• Climate change – Identification of health effects
• Involved in the light brown apple moth controversy: Issued report on the complaints of adverse health effects after aerial spraying in Monterey and Santa Cruz.

Organizational structure

OEHHA has three main divisions and offices:

• Division of Scientific Programs
• Administrative Services Division
• Office of External and Legislative Affairs
• Office of the Chief Council
• Office of External and Legislative Affairs

The Division of Scientific Programs is composed of four scientific branches that correspond to the scientific duties:

• Air and Site Assessment and Climate Indicators Branch
• Community and Environmental Epidemiology Research Branch
• Pesticide and Environmental Toxicology Branch
• Reproductive and Cancer Hazard Assessment Branch

Employee composition

OEHHA's scientific responsibilities are fulfilled by a highly educated and trained professional staff of about 120 individuals. The staff include toxicologists, epidemiologists, biostatisticians and physicians; many have international reputations in their scientific fields. In fiscal year 2007–2008 OEHHA was budgeted for approximately $17.5 million or 1/500th of 1% the state General Fund; $8 million is from the general fund.

Who uses OEHHA's science?

State agency users of information on issues of environmental and public health include:

• All six boards and departments within Cal/EPA
• California Department of Public Health
• California Department of Food and Agriculture
• California Office of Emergency Services
• California Department of Fish and Game
• California Department of Justice
• Federal agencies
• Scientific community including non-governmental organizations (NGOs)
• Industries in a range of disciplines
• General public

History

OEHHA was established in its current form by Governor Pete Wilson on July 17, 1991 with the creation of Cal/EPA. OEHHA originated in the 1950s for air epidemiology in the Department of Public Health and developed over time with increased public awareness of the environment. OEHHA is the smallest of the six boards, departments and offices within Cal/EPA. OEHHA has no regulatory authority but remains the risk assessment and scientific arm of Cal/EPA and provides health-protective scientific guidance for Cal/EPA. Additionally, OEHHA is the lead agency for Proposition 65 implementation, a ballot measure approved in 1986, titled The Safe Drinking Water and Toxic Enforcement Act of 1986. The highly experienced team of experts is well respected in the scientific community and has been built up over more than twenty years. The quality and depth of OEHHA's commitment to public health, the environment and sound science is illustrated by the scientific quality of the risk assessments produced.

OEHHA is headquartered in the Cal/EPA building in Sacramento and has an office in the Oakland Elihu Harris State Building. Before the state building was built, the Oakland office used to be located across from the University of California, Berkeley; OEHHA has maintained academic ties with this institution.

Attempted closure

In May 2009, Governor Arnold Schwarzenegger proposed to "eliminate and transfer the functions" of OEHHA (and other agencies) as part his May Revise for the 2009–2010 budget. Details about the transfer of functions including mandates, funding, staff resources, and new head agency are limited. Elimination of OEHHA would have had a small impact on the budget problems because of several reasons: (1) OEHHA's budget is very small (1/500th of 1% of the General Fund, or 1/50,000th) compared to the state deficit; $8.3 million of OEHHA's budget is general fund (2) about half of OEHHA's budget is funded by special funds (e.g. Proposition 65, Biomonitoring) (3) state mandates that transfer to other agencies or departments will still require funding.

Press

On June 2, 2009 articles and editorials/opinions were published in the Los Angeles Times, Sacramento Bee, California Progress Report, SFGate and others that speak to the importance of OEHHA and further explain how cutting OEHHA would not save a significant source of funding. These articles coincide with the California Budget Conference Committee hearings on the afternoon of June 2, 2009.

Budget Conference Committee Hearing

On June 2, 2009 the Budget Conference Committee convened a hearing for public comment on the Governor's budget proposal. The hearing is archived on video, the testimony on behalf of OEHHA begins at 3:49:11 The supporters of OEHHA proposed and alternative to keep OEHHA intact and save $8.3 million, OEHHA's general fund budget. The proposal includes alternative funding sources and also expands OEHHA with the addition of Department Pesticide Regulation's risk assessment activities, Department of Toxic Substances Control's hazard evaluation functions, and lead roles in the children's health initiative and the Cal/EPA portion of the biomonitoring program. The main argument against the Governor's proposal is that the science performed in OEHHA should be independent of policy decisions made by the other boards and departments of Cal/EPA.

Senate Environmental Quality Committee Hearing

On June 10, 2009, The Senate Environmental Quality Committee voted to recommend that OEHHA be kept intact and expanded with the addition of California Department Pesticide Regulation's risk assessment activities, California Department of Toxic Substances Control's hazard evaluation functions, and lead roles in the children's health initiative and the Cal/EPA portion of the biomonitoring program. The recommendation will be forwarded to the Budget Conference Committee. The vote was 3-2. Senator Ashburn voted against the expansion recommendation but also said, "The expertise that resides in OEHHA ought not to be dissipated throughout state government as the Governor proposes."

External links

• Oehha.ca.gov: Official California Office of Environmental Health Hazard Assessment website
• Oehha.ca.gov: "About the California OEHHA—Office of Environmental Health Hazard Assessment"