This, the tenth edition of the report, was forwarded to Congress and released to the public today by the Department of Health and Human Services. It was prepared by the National Toxicology Program, an arm of the HHS located at the National Institute of Environmental Health Sciences, one of the National Institutes of Health. The reports are published every two years after lengthy study and scientific reviews by three successive expert panels of government and non-government scientists.

In a statement releasing the report, HHS Secretary Tommy Thompson today thanked "the hundreds of scientists who have contributed to this report through their original research or their careful reviews of these important studies. The public is well served by this dispassionate report that helps all of us ensure that the American public is made aware of potential cancer hazards."

The tenth report newly lists the group of hormones known as steroidal estrogens as "known human carcinogens." A number of the individual steroidal estrogens were already listed as "reasonably anticipated carcinogens" in past editions, but this is the first report to so list all these hormones, as a group. As with all the other medications listed, the "Report on Carcinogens" does not address or attempt to balance potential benefits of use of these products.

Also newly listed as "known" causes of cancer in humans are broad spectrum ultraviolet radiation, whether generated by the sun or by artificial sources; wood dust created in cutting and shaping wood; nickel compounds and beryllium and its compounds commonly used in industry. Beryllium and beryllium compounds are not new to the list but was previously listed as "reasonably anticipated to be a human carcinogen."

The report is mandated by Congress as a way for the government to help keep the public informed about substances or exposure circumstances that are "known" or are "reasonably anticipated" to cause human cancers. The report also identifies current regulations concerning these listings in an attempt to address how exposures have been reduced.

The report makes a distinction between "known" human carcinogens, where there is sufficient evidence from human studies and "reasonably anticipated" human carcinogens, where there is either limited evidence of carcinogenicity from human studies and/or sufficient evidence of carcinogenicity from experimental animal studies.

The report does not assess the magnitude of the carcinogenic risk, nor does it address any potential benefits of listed substances such as certain pharmaceuticals. Listing in the report does not establish that such substance presents a risk to persons in their daily lives. Such formal risk assessments are the responsibility of Federal, State, and local health regulatory agencies.

NEWLY LISTED AS KNOWN HUMAN CARCINOGENS ARE:

STEROIDAL ESTROGENS. These are 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. The report cites data from human epidemiology studies that show an association between estrogen replacement therapy and a consistent increase in the risk of endometrial cancer (cancer of the endometrial lining of the uterus) and a less consistent increase in the risk of breast cancer.