Steroidal estrogens, wood dust and more than a dozen other substances have been added to the government's official list of materials that can cause cancer.
Studies released this year by the National Cancer Institute and others have linked long-term estrogen use to breast and ovarian cancer, raising concerns among women who use the hormone.
A federal advisory panel recommended the hormone be listed as a cancer agent two years ago, and the National Institute of Environmental Health Sciences made it official this week with the publication of its biennial report on carcinogens.
The report, listing substances that are known or reasonably anticipated to cause a cancer risk, was sent to Congress and released by the Department of Health and Human Services.
While the expert panel recommended that the group of hormones known as steroidal estrogens be listed as cancer risks, members observed that they have benefits as well as dangers. The substances are used in hormone replacement therapy and oral contraceptives.
The panel did not suggest banning estrogens but said officially linking them with cancer could make it more probable that physicians would discuss both risks and benefits when discussing options with their patients.
The 10th annual cancer report brings to 228 the number of substances linked to cancer.
While the new report lists steroidal estrogens as "known human carcinogens," some of the individual steroidal estrogens had been listed as "reasonably anticipated carcinogens" in past editions.
Also newly listed as known causes of cancer in humans are broad-spectrum ultraviolet radiation - whether generated by the sun or by artificial sources - and wood dust.
The report, issued every two years, is required by Congress to help keep the public informed about substances or exposure circumstances that are known or are reasonably anticipated to cause human cancers. It does not determine how great the risk is or any balancing benefits from the substances.
Added to the list were of known carcinogens were: Steroidal estrogens, a group of related hormones that control sex and growth characteristics and are commonly used in estrogen replacement therapy to treat symptoms of menopause and in oral contraceptives. Broad spectrum ultraviolet radiation produced by the sun and by artificial sources, such as sun lamps or tanning beds, in medical diagnosis and treatment procedures, and in industry for promoting polymerization reactions. Wood dust created when machines and tools cut, shape and finish wood. Wood dust is particularly prevalent in sawmills, furniture manufacture and cabinet making. Nickel compounds used in many industrial applications as catalysts and in batteries, pigments and ceramics. Beryllium and beryllium compounds inhaled in dust by miners and also exposed to ceramics workers, missile technicians, nuclear reactor workers, electric and electronic equipment workers and jewelers.
Twelve substances or groups of substances are newly listed as "reasonably anticipated to be human carcinogens." These include: IQ, or 2-amino-3-methylimidazo 1/84,5-f 3/8quinoline, and other compounds formed during cooking at high temperatures of such foods as meats and eggs and also found in cigarette smoke.2,2-bis-(Bromomethyl)-1,3-propanediol, a flame-retardant chemical used to make some polyester resins and rigid polyurethane foam. Ultraviolet A, ultraviolet B and ultraviolet C radiation, which have shown a relationship to skin cancer. Chloramphenicol, an antibiotic with restricted use in the United States because it can cause fatal blood disorders. The listing is based on a report showing increased incidence of leukemia after use of the drug. 2,3-Dibromo-1-propanol, a chemical used as an intermediate in the production of flame retardants, insecticides, and pharmaceuticals. Dyes metabolized to 3,3'-dimethoxybenzidine, that have been used to color leather, paper, plastic, rubber and textiles. Dyes metabolized to 3,3'-demethylbenzidine that have been used in printing textiles, in color photography and as biological stains. Methyleugenol, which occurs naturally in oils, herbs and spices and is used in smaller amounts in its natural or synthetic form in flavors, insect attractants, anesthetics and sunscreens. Metallic nickel, used mainly in alloys with most exposures by inhalation or skin contact in the workplace. Metallic nickel is not contained in the nickel coin. Styrene7,8-oxide, used in producing reinforced plastics and as a chemical intermediate for cosmetics, surface coatings, agricultural and biological chemicals. Vinyl bromide, which has been used in polymers, in making fabrics for clothes and home furnishings, as well as in leather and metal products, drugs and fumigants. Vinyl fluoride, which is used in making polyvinyl fluoride and related weather-resistant fluoropolymers.
By Randolph E. Schmid
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