The review panel of the National Toxicology Program's Board of Scientific Counselors approved the listing unanimously. This recommendation had already been approved in two earlier scientific reviews, whose findings were made public today. The draft document said, "Human studies have shown that exposure to solar radiation is causally related to skin cancer, and that use of sunlamps or sunbeds is associated with skin and eye cancer."
While sunlight has long been linked to skin cancers, including sometimes-fatal malignant melanoma, today's recommended designation makes clear that sunlamps, tanning booths and other artificial sources of UV light are also hazardous, regardless of the claims of operators. Up to 10 percent of Americans -- mostly young women -- were estimated during today's discussion to have used artificial tanning devices.
The discussion document also said that an estimated half a million welders in the United States are the largest occupational group exposed to artificial ultraviolet radiation. This results from their use of electric arc welding equipment.
Meeting at the headquarters of the National Institute of Environmental Health Sciences and the affiliated National Toxicology Program in Research Triangle Park, N.C., the panel operated under new rules that permit mixes, as well as single chemicals, to be listed in the Report on Carcinogens.
The panel took this first opportunity, under the revised rules, to recommend that smokeless tobacco such as snuff and chewing tobacco, and inhaled tobacco smoke be officially listed as "known" to cause cancer in humans.
Chemicals in tobacco smoke and in tobacco are already listed in the report but the new listing would make clear that tobacco products as a whole, whether chewed or smoked as cigarettes, pipe tobacco and cigars, cause cancer in humans.
No one from industry asked to speak against the designation.
Tomorrow morning the panel takes up a proposal to remove saccharin from the list of "anticipated" human carcinogens. Like all the proposed listings, the de-listing has already been through two scientific reviews. Whereas many of the scientific reviews of other chemicals ended in unanimous or near-unanimous votes, the first scientific review was reported today to have resulted in a 7-3 vote to de-list, and the second a 6-2 vote to de-list. The current review by a special subcommittee of the NTP's Board of Scientific Counselors is the first to be public, and it is influential but not the final word. It makes recommendations to NIEHS/NTP Director Kenneth Olden, Ph.D., who in turn makes recommendations to Health and Human Services Secretary Donna E. Shalala.
Today, the advisors also recommended that:
TETRAFLUORETHYLENE, a chemical used in producing Teflon and other polymers, as well as having been used as a propellant for food product aerosols, be listed as "reasonably anticipated to be a human carcinogen."
CADMIUM and CADMIUM COMPOUNDS, used in batteries, coating and plating, plastic and synthetic products and in alloys, be upgraded from "reasonably anticipated" to "known to be a human carcinogen."
CHLOROPRENE, used as a monomer for neoprene elastomers, industrial rubber products, and as a component of adhesives in food packaging, be listed as reasonably anticipated to be a human carcinogen.
1,3-BUTADIENE, used in making synthetic rubber, be upgraded to be "known to be a human carcinogen."
STRONG INORGANIC ACID MISTS CONTAINING SULFURIC ACID, used to make fertilizers, rayon and other fibers, pigments and colors, explosives, plastics, coal-tar products such as dyes and drugs, storage batteries, detergents, rubber, pulp and paper, cellophane and catalysts. It is also used in refining petroleum, in ore concentration and in removing impurities from iron, steel and other metals to be listed as a known human carcinogen.
TAMOXIFEN, a drug used to reduce the risk of a return of breast cancer, be listed as a known human carcinogen, but with a strong emphasis in the report that its benefits greatly outweigh the risks. (As with many cancer drugs, the labeling already reports animal studies indicating the drug may sometimes cause cancer in animals or humans.)
PHENOLPHTHALEIN, an ingredient in some nonprescription laxatives, as an "anticipated human carcinogen." The research by the National Institute of Environmental Health Sciences on which this recommendation is based recently caused the Food and Drug Administration to question its safety as a nonprescription drug. Drug manufacturers have now abandoned its use.