EPA Says Toxic Chemicals Pose Added Cancer Risk

The first nationwide study of 32 common toxic chemicals shows that for 20 million Americans--many of them living in the Los Angeles and San Francisco Bay areas--the pollutants pose a cancer risk 100 times greater than what the Environmental Protection Agency usually considers acceptable.

The data released Friday suggest that 200 million Americans face a 1 in 100,000 lifetime risk of developing cancer from these pollutants, while the risk posed to residents of Los Angeles and the Bay Area was as high as 1 in 5,000.

“This should not be viewed as a major cause of alarm,” Jeff Holmstead, an EPA assistant administrator, said of the agency’s study. “The average cancer risk to someone in the United States is roughly 1 in 3.”

So these toxins represent “a very small portion of the overall cancer risk,” he said.

EPA pollution-reduction programs typically target sources that cause cancer risks of between 1 in a million and 100 in a million, Holmstead said.

Cars, trucks and other mobile sources of pollution emit about half of these toxic contaminants, the most dangerous of which include benzene, formaldehyde, acetaldehide and butadiene. Most of the rest comes from natural sources, such as forest fires, or from industrial facilities.

But environmentalists urged the EPA to consider the data a call to action.

“Many millions of people are exposed to levels of cancer-causing chemicals in the air they breathe at levels far higher than EPA considers acceptable,” said Frank O’Donnell, executive director of Clean Air Trust, an environmental group that tracks air policy.

“The study adds urgency to EPA’s efforts to address the problem of toxic air pollution head-on,” said Emily Figdor, a clean air advocate for U.S. Public Interest Research Group, an environmental group. “This is a long overlooked public health problem.”

In particular, O’Donnell said, the data underline the need for the agency to regulate the emissions of vehicles that don’t operate on the highways, such as construction equipment, which spew a disproportionately large amount of pollutants into the air.

Numerous studies since the 1980s have linked chemicals in California air pollution to cancer and other heath hazards. Voters approved Proposition 65 in 1986 requiring manufacturers of products containing toxic chemicals to notify people whenever they were being exposed.

In a comprehensive study in Southern California three years ago, air quality officials found that toxic air pollution posed an excessive cancer risk for millions of people in the Los Angeles region. For every million residents, about 1,200 to 1,400 were at risk of contracting cancer from hazardous air pollutants, ranking dirty air as one of the most dangerous environmental health hazards.

Communities such as Pico Rivera, Huntington Park and San Pedro had some of the highest levels of air toxins, although toxic air pollution is worse--and the risk greater--typically along major freeways, including the Santa Ana Freeway between downtown Los Angeles and Orange County and along the Long Beach Freeway.

The study found that diesel exhaust from buses and trucks constituted about 71% of the hazard; other vehicles accounted for about 20% of the harmful emissions; and refineries and factories made up the balance. Toxic air pollutants are chemicals that not only make the sky dirty but can cause cancer, reproductive damage and neurological impairment.

Holmstead said the EPA study shows that on-road and off-road vehicles contributed roughly equal amounts to the cancer risk.

The data used in the study were collected by states in 1996, and EPA officials said new regulations implemented as a result of the 1990 Clean Air Act amendments should be reducing emissions of these toxic chemicals.

Nonetheless, Holmstead said the study represents an “extraordinarily ambitious analytical effort” and said the EPA would attempt to release new data every three years.

The assessment does not include results for dioxins, compounds that contribute significantly to cancer risks.

Despite the study’s limitations, EPA officials said the data would help them decide which sources of air pollution should be targeted for greater reductions.

“That is a very powerful tool for us,” said Bill Wehurm, an EPA attorney. “It can help show us where we can get the most bang for the buck; where emissions reductions are going to make the greatest benefit.”

Holmstead said it was too early to say which sources of pollution would face tighter regulations as a result of this data.

Holmstead also stressed that when the EPA estimates cancer risks, it uses the high end of a range of risk at a given exposure level.

The data also assessed non-cancer health risks posed by the pollutants.

Many of them cause adverse effects in humans or animals by irritating the lining of the respiratory system, the study said.

For nearly the entire U.S. population, the so-called hazard index for respiratory effects exceeded 1, which indicates a potential may exist for adverse health effects. For 20 million Americans, including those in the L.A. and Bay areas, this hazard index exceeded 10.

EPA researchers spent years working on the study, and the data it contained were complicated. EPA posted the information on its Web site late Friday without prior notice and did not hold a news conference to explain it.

“It does create the appearance that they were trying to bury the information,” O’Donnell said.

The Bush administration wants to give industry more leeway in how it cleans up its air emissions. It has unveiled a plan to reduce emissions of three major pollutants from power plants with a trading system that would give polluters financial incentives to cut emissions.

Environmentalists have criticized the plan, saying it would not be as effective at cleaning up the air as an aggressive application of current air pollution laws.

The administration also has been criticized for reversing a campaign pledge to cut power plant emissions of carbon dioxide, which most scientists agree is the major man-made contributor to global warming.

EPA officials said the health risk posed by the toxics covered in the new study pales compared to the risk caused by emissions of sulfur dioxides and nitrogen oxides, a large proportion of which come from power plants and vehicles. The fine particulates cause thousands of early deaths from heart disease and lung disease.

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Times staff writer Gary Polakovic in Los Angeles contributed to this report.