Environmental Tobacco Smoke: Background

This page updated November 30, 2010

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What is ETS?

Environmental tobacco smoke (ETS), also known as second-hand smoke, is a complex mixture of chemicals generated during the burning and smoking of tobacco products (cigarettes, pipe tobacco, cigars, etc.).  Researchers have identified over 4,000 individual constituents in ETS, many of which are known or suspected human carcinogens and toxic agents: benzene, 1,3-butadiene, polycyclic aromatic hydrocarbons, N-nitrosamines, nicotine, and particulate matter are just some of the toxic chemicals released during the burning of tobacco products.

What is a Toxic Air Contaminant?

A Toxic Air Contaminant (TAC) is an air pollutant "which may cause or contribute to an increase in mortality or in serious illness, or which may pose a present or potential hazard to human health." This definition is provided in the California Health and Safety Code (39655). California law requires the Air Resources Board (ARB) to identify potential TACs and thoroughly investigate possible exposure and adverse health effects. The Toxic Air Contaminant Identification and Control Act (AB 1807, Tanner 1983) created the TAC Program. ETS was entered into the identification process in 2001.

What steps did the ARB take to identify ETS as a TAC?

Numerous health studies have associated exposure to ETS with a variety of serious illnesses affecting children and adults. These associations were reviewed and summarized by the Cal/EPA Office of Environmental Health Hazard Assessment (OEHHA), first in 1997 and then again in 2005. The 2005 health effects summary became part of the ETS TAC identification report. A thorough public process was followed during the ETS TAC identification phase, assuring accountability and public input.  Public workshops were conducted to allow for direct exchanges of information between interested parties.  The final report includes a record of the public comments and the agency's responses.  The findings in the health effects and exposure reports done during the TAC identification phase were reviewed by the State's Scientific Review Panel. There was overwhelming evidence that many Californians were exposed to ETS and that these exposures could result in thousands of cases of illness or premature death. ETS was formally identified as a TAC at the Board meeting on January 26, 2006.

What are the health effects associated with ETS?

Developmental effects such as low birth weight, Sudden Infant Death Syndrome (SIDS), and pre-term delivery have been causally associated with ETS. These effects led to the decision by OEHHA to place ETS on the list of chemicals known to cause reproductive toxicity. Children can be affected by ETS exposure with increased numbers of acute lower respiratory tract infections (e.g., bronchitis and pneumonia), chronic respiratory symptoms, asthma induction and exacerbation, and middle ear infections. These effects, and the potential for ETS to have a disproportionate effect on children, led to the listing of ETS as an SB25 compound. SB25 compounds are air pollutants known to the state to have effects on children that may make them especially vulnerable to illness. Asthma indcution and exacerbation may also affect adults, and adults may experience eye and nasal irritation as a result of exposure to ETS. The potential arcinogenic effects of ETS exposure are: lung cancer, nasal sinus cancer, and breast cancer in younger (primarily premenopausal) women. Cardiovascular effects of ETS exposure are: heart disease mortality, acute and chronic coronary heart disease, and altered vascular properties. The Executive Summary of the ETS Staff Report lists OEHHA's estimates of the health effects that could be expected in California based on the prevalence of ETS exposure in the State.