Substances in Products Many Americans Encounter Daily Added to Government Carcinogen List

June 11, 2011

Americans may be alarmed to find they are suffering exposure to substances in everyday products that the government added to a list of cancer-causing dangers.

The science-based Report on Carcinogens is a congressionally mandated report prepared by the National Toxicology Program for the U.S. Department of Health and Human Services (HHS) that identifies substances and exposure circumstances that are known or reasonably anticipated to cause cancer in humans.

"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, Ph.D., director of both the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program (NTP).

John Bucher, Ph.D., associate director of the NTP added, "This report underscores the critical connection between our nation’s health and what’s in our environment."

The report includes a profile for each substance on the list, which provides information from cancer studies that support the listing, as well as information about potential sources of exposure and current federal regulations to limit exposures.

Some industry organizations are not happy about results in the report.

“It will unfairly scare workers, plant neighbors and could have a chilling effect on the development of new products,” Tom Dobbins of the American Composites Manufacturers Association (ACMA) told The New York Times. “And our companies are primarily small businesses, and this could hurt jobs and local economies.”

The agency added formaldehyde and aristolochic acids to its list of known human carcinogens.

• Formaldehyde moved up from the list from reasonably anticipated human carcinogens where it resided since 1981 to the known carcinogen list this year. While some people may associate formaldehyde with laboratories and funeral homes, manufacturers use formaldehyde in everyday products such as plastics, fabrics, fibers such as those in carpet, paper coatings, composite wood products such as plywood and particleboard, and hair products. Industrial fungicides, germicides and disinfectants often contain formaldehyde.
  Materials that contain formaldehyde can release formaldehyde gas into the air. Exposure generally occurs by inhalation of this gas or by skin contact with liquids containing the chemical.
  Workers at manufacturing facilities may by be at greatest risk of cancer from exposure to formaldehyde. According to the National Cancer Institute, studies show that workers exposed to formaldehyde developed cancers such as nasopharyngeal cancer and leukemia.

• Consumers may suffer exposure to aristolochic acids in dietary supplements and botanical or herbal remedies containing Aristolochia. They have caused high rates of bladder or upper urinary tract cancer among individuals with kidney or renal disease who took the remedies.
  The U.S. Food and Drug Administration (FDA) issued an alert in April advising consumers to avoid use of these supplements due to permanent kidney damage, sometimes resulting in kidney failure that has required kidney dialysis or kidney transplantation.

The agency added captafol, cobalt-tungsten carbide, glass wool fibers, o-Nitrotoluene, riddelliine and styrene to its list of anticipated human carcinogens.

• Captafol is a fungicide used on fruits, vegetables, ornamental plants, grasses and seeds that caused tumors in rats and mice ingesting it in their diet. Although the U.S. banned captafol use in 1999, people exposed prior to that date may still develop related cancers.
• Manufacturers use cobalt-tungsten carbide in powder and metal form for an array of hard metal products including metal dies, tools for cutting and grinding, and other wear resistant products. Sometimes called cemented or sintered carbides, industries such as mining, and oil & gas drilling often use these hard metals in equipment. There is some evidence of industrial workers developing lung cancer associated with cobalt-tungsten carbide.
• Animal studies showed certain glass wool fibers are carcinogenic. The glass wool fibers on the agency’s list are those that are inhalable, highly durable and remain in the lungs for long periods. The most common use for these glass wool fibers is building insulation.
• o-Nitrotoluene is a substance used in the preparation of dyes, including magenta and various sulfur dyes used to color cotton, wool, silk, leather and paper. Some agricultural chemicals, rubber chemicals, pesticides, petrochemicals, pharmaceuticals and explosives also contain o-Nitrotoluene. Animal studies show it causes a variety of tumors in rats and mice.
• Riddelliine is found in certain plants of the genus Senecio, a member of the daisy family commonly called ragwort and groundsel. While Senecio is only eaten or used in herbal remedies outside the U.S., the agency worries that people will ingest riddelliine from eating or drinking herbal medicine or teas, honey, foods contaminated by parts of Senecio plants, or eating products from animals that have fed on the plants. This substance has caused cancers of the lungs, blood vessels and livers of rodents.
• Manufacturers use the synthetic chemical styrene in a wide array of consumer and industrial products, including Styrofoam, rubber, plastic, insulation, fiberglass, pipes, automobile parts, food containers and carpet backing. Workers exposed to styrene have developed lymphohematopoietic cancer and genetic damage in their white blood cells, or lymphocytes.

Anyone can nominate a substance to the National Toxicology Program for the Report on Carcinogens. The NTP conducts a formal evaluation with a public comment period before deciding if the substance deserves inclusion on the list or removal from the list. There are a total of 240 substances currently listed, including 54 listed as known to be a human carcinogen and 186 listed as reasonably anticipated to be a human carcinogen.

“This is a really big deal, because the chemical industry has been fighting tooth-and-nail to prevent these assessments – actually to prevent the whole report – from being finalized,” said Jennifer Sass of the environmental action group Natural Resources Defense Council (NRDC). “It’s been held up for four years by industry interference, but the public has a right to know about the chemical risks that are foisted upon us through air and water pollution, off-gassing from consumer products, inadequate or unenforced regulations, etc.”