Styrene Cancer Warning Upheld

Styrene, a chemical found in many consumer products, should at least be listed as a “reasonably anticipated” human carcinogen in the federal “Report on Carcinogens,” the National Research Council says in a new report.

The chemical industry has fought for years to keep styrene out of the “Report on Carcinogens,” which the National Toxicology Program compiles. NTP first listed styrene—which is found in plastic packaging, food containers, and other consumer goods—as a reasonably anticipated human carcinogen in 2011. Release of that report had been delayed four years because of opposition from industry groups.

The Styrene Information & Research Center (SIRC), which represents manufacturers of styrene, sued the federal government in 2011 to have the listing removed. It lost the case. But SIRC successfully lobbied Congress to add to a 2012 appropriations bill a provision mandating that NRC review the styrene listing.

The NRC report, released last week, goes beyond the government’s assessment of styrene as a reasonably anticipated human carcinogen. The report says styrene could be listed as a “known” human carcinogen if greater consideration is given to data from toxicity tests on human tissue or cells.

Environmental advocacy groups are welcoming the report. They say NRC seems to be urging the government to rely more on data from tests that don’t involve laboratory animals, such as high-throughput cellular assays, to strengthen the classification of cancer-causing chemicals. “This is a big deal” because government agencies are grappling with how to use that type of data to inform risk assessments, says Jennifer Sass, a senior scientist with the Natural Resources Defense Council.

Industry groups, meanwhile, continue to claim that products containing styrene are safe.

“Consumers are not at risk from products made from styrene,” says Jack Snyder, executive director of SIRC. NTP agrees human exposure to styrene from consumer products is likely minimal. Other sources of exposure to the substance include cigarette smoke and vehicle exhaust. The biggest exposure, according to NTP, is to workers who process the chemical.