California Air Resources Board

Background

Dioxins can be emitted from a variety of sources including waste incineration, some chemical manufacturing processes, cars and trucks, and other industrial sources that burn fuel. Dioxins can also be emitted from other sources such as forest fires and residential wood burning. 

Dioxins can be inhaled directly or can contaminate vegetation that are a food source for animals and humans. CARB has identified dioxins as a toxic air contaminant (TAC) and they are listed as hazardous air pollutants by the United States Environmental Protection Agency (U.S. EPA).

In 1990, CARB adopted the Dioxin Airborne Toxic Control Measure for Medical Waste Incinerators  to reduce emissions of dioxins from medical waste incinerators by 99 percent.  At that time, medical waste incinerators were one of the largest known air sources of dioxins in California. As a result of the control measure, the number of medical waste incinerators in the state dropped sharply.

In 2003, CARB approved the Airborne Toxic Control Measure (ATCM) to reduce air emissions of dioxins and other TACs from outdoor residential waste burning. Beginning January 1, 2004, no household trash or garbage can be burned outdoors at residences. More information

Airborne Toxic Control Measure (ATCM) to Reduce Emissions of Dioxins

Health Effects

Studies have shown that exposure to dioxins can cause cancer or other non-cancer health effects. Probable routes of exposure to dioxins are inhalation, ingestion, and skin exposure. A nursing baby may also be exposed to dioxins through its mother's milk. Studies have shown that exposure to dioxins has caused chloracne, liver toxicity, skin rashes, nausea, vomiting, and muscular aches and pains. The immune system also appears to be very sensitive to dioxin toxicity. The Office of Environmental Health Hazard Assessment (OEHHA) has listed dioxin as a compound in which infants and children may be especially susceptible to illness. Additional information on dioxin health effects for children can be found on OEHHA's website.

In addition to the toxicity of dioxins there is concern about dioxins because of the long persistence in the environment and in the body. Emissions into the air can result in deposition onto crops, grass, and feed. These deposited dioxins are either eaten by humans directly or eaten by livestock and become a source of contamination for humans in beef, poultry and dairy products. In addition, subsistence fisherman can have unusually high levels of dioxin. Generally with dioxins, the potential health risk from what you breathe is relatively insignificant compared to the potential risk from the food we eat or soil we incidentally ingest. For this reason, it is appropriate to conduct a multipathway health risk assessment rather than just an inhalation-only health risk assessment. Information on how to conduct health risk assessments can be found on OEHHA's website.

Air Monitoring

In 2002, CARB initiated the California Ambient Dioxin Air Monitoring Program (CADAMP) to collect comprehensive information on the ambient levels of dioxins, furans, biphenhyls, and diphenylethers in populated urban areas. View more detailed information, including the monitored results, and data analysis.

Related Information

U.S. EPA's Reassessment of Dioxins

U.S. EPA: Dioxins and Related Compounds

U.S. EPA: Dioxin Exposure Initiative Publications

CARB: Outdoor Residential Waste Burning

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