Formaldehyde, a preservative used in labs and mortuaries, and styrene, the chemical used to make styrofoam cups and food containers, were among six chemicals that were added today to the U.S. health department's list of chemicals that are known to cause cancer or could raise the risk of cancer.
Formaldehyde, which is also used in the manufacturing of household products, and aristolochic acids, which are present in some plant species, were classified by government scientists as known carcinogens, according to the National Institute of Environmental Health Sciences (NIEHS) report. Certain herbal medicines and botanic foods may contain aristalochic acids as a contaminant.
Styrene, riddelliine (found in certain plant species), captafol (a pesticide), cobalt-tungsten carbide (a metal in powder or hard form), certain kinds of inhalable glass wool fibers (used for insulation) and o-nitrotoluene (used in the production of dyes and chemicals) were classified as substances that can reasonably be anticipated to be human carcinogens, the NIEHS said.
People are usually exposed to styrene by working in a manufacturing environment, as the chemical is used to make plastics and rubber for insulation, car parts, pipes, food containers and carpet backing, according to the report. Smokers are also exposed to styrene because the chemical is present in cigarette smoke. The chemical can also leach out from styrofoam containers, but the levels that are released are very low, the report said.
Some studies have shown that styrene increases the risk of leukemia and lymphoma in humans, and lung cancer in mice, according to the report.
"Reducing exposure to cancer-causing agents is something we all want, and the Report on Carcinogens provides important information on substances that pose a cancer risk," said Linda Birnbaum, director of both the NIEHS and the National Toxicology Program, in a press release.
The Report on Carcinogens now includes 240 items. Some known carcinogens in the report include arsenic, asbestos, mustard gas, certain strains of the human papillomavirus, solar radiation, tobacco smoke and wood dust. "Reasonably anticipated" human carcinogens include chloroform, progesterone and diesel exhaust.