Jun 2, 2002 4 min read

WASHINGTON (AP) – Toxic chemicals pose an elevated cancer risk to two-thirds of Americans living in nearly every part of the country, says an assessment by the Environmental Protection Agency. A long-awaited study of health risks from 32 toxic chemicals, released Friday, concludes that 200 million people live in areas where the cancer risk from exposure to these substances is higher than what the EPA considers a minimum level of concern.

The assessment, based on 1996 data, found that automobile and truck emissions are a major cause of exposure to the chemicals, with power plants and other industrial sources also involved.

The study, described as a “snapshot” of health risks from air toxins, found that the chemicals can be expected over a lifetime of exposure to cause 10 additional cancers for every 1 million people. These risks can be found across virtually the entire country, said the study, which was reviewed by outside scientists.

“More than 200 million people live in census tracts where the combined upper bound lifetime cancer risk from these (chemical) compounds exceeded 10 in 1 million risk,” s in areas where the risks are even higher – 100 additional lifetime cancers for every 1 million people.

The EPA considers a cancer risk of greater than one in a million or greater as a matter of concern, although those levels do not always trigger regulatory actions.

“The risks are very much in line with what we expected all along,” said Jeffrey Holmstead, head of the EPA’s air office.

He said the risks of cancer from toxic chemical exposure still “are very, very small” compared with overall cancer risks from all sources, and are likely smaller than suggested by the study.

“Since that time (1996), the risks already have been reduced significantly,” he said in an interview late Friday after the study was placed on the EPA’s Web site.

Holmstead said the report was “designed to be a baseline” for further studies on risks posed by air toxins. Another assessment is expected to be issued next year based on more recent data.

But environmentalists said the study’s findings provide clear evidence that tougher measures are needed to reduce releases of toxic chemicals – such as benzene, mercury, formaldehyde and other carcinogens – from automobiles, power plants and industrial sources.

They show “a lifetime cancer risk at least 10 times greater than the level considered acceptable by the EPA,” said Emily Figdor of the U.S. Public Interest Research Group. “These findings are a wake-up call that EPA should take action to reduce this long-overlooked public health threat.”

Among the study’s conclusions is that automobiles and trucks contribute substantially to the public’s exposure to cancer-causing air toxins.

It estimated that 100 million people live in areas where motor vehicles – both on- and off-road – account for an additional lifetime cancer risk of at least 10 in a million.

The study also concluded that toxic chemicals pose a significant health hazard other than cancer to much of the U.S. population, especially problems with respiratory systems.

The report said the assessment should be viewed as a “snapshot” that identifies the greatest health risks from toxic chemicals and identify the areas of most potential concern, but not as an analysis to determine what levels of risks are acceptable or not acceptable.

The authors also cautioned that the risk analysis was subject to limitations “due to gaps in data or in the state of the science for assessing risk.”

In some cases the shortcomings may have understated the risks, the authors suggested. For example, the study did not attempt to assess various dioxin compounds “that may contribute substantially to (cancer) risks,” they wrote.

In addition, the study noted, the EPA is reassessing the health effects of the 32 toxic chemicals that were studied and that the reassessment could show an increase in the overall risks that the chemicals pose.

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On the Net: EPA’s National Air Toxic Assessment: www.epa.gov/ttn/atw

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