NIH News Advisory
National Institute of
Environmental Health Sciences

Friday, May 2, 1997

Bill Grigg, NIEHS
(919) 541-2605
Sandy Lange, NTP
(919) 541-0530

NTP Proposes 15 Drugs, Dyes and Other Chemicals
for Carcinogen Listing

The National Toxicology Program has announced its intent to list 15 substances -- including drugs, diesel combustion products, a solvent and a dye -- as known or likely human carcinogens in the Eighth Biennial Report on Carcinogens, a report from the Secretary of Health and Human Services to Congress.

Large numbers of Americans have been exposed to the substances—one of the criteria for their listing. But some, such as the laxative ingredient Danthron, were removed from the market as early as the 1980s when initial tests leading up to this report were completed. Others—including several cancer drugs and the organ transplant drug Cyclosporin—have remained on the market because their potential benefits outweigh their risk. Listings in the report are intended as statements of fact, not a recommendation for a ban or other specific action -- though regulatory agencies may sometimes follow-through with such an action.

In the eighth report, NTP is proposing two substances as known human carcinogens. One is Cyclosporin. The second is Theotepa, a cancer drug previously listed as a likely human carcinogen, or "Reasonably anticipated to be a human carcinogen."

The 13 remaining agents, substances or mixtures are being proposed to be added as reasonably anticipated to be human carcinogens.

The FR Notice is on pages 23469 and 23470, Volume 62, Number 83. It can be accessed from the Federal Register Online via GPO Access []

Comments may be sent through May 30 to the National Toxicology Program, Biennial Report on Carcinogens, WC-05, P.O. Box 12233, Research Triangle Park, NC 27709.

The NTP, which is headquartered at the National Institute of Environmental Health Sciences, an institute of the National Institutes of Health, also invites the public to nominate chemicals for testing that may be carcinogenic and that large numbers of Americans are exposed to. Nominations can be sent to the same address.

The list of proposed chemicals follows.

Agents, Substances or Mixtures proposed for listing in the Eighth Biennial Report on Carcinogens

PROPOSED to be listed as known human carcinogens

CYCLOSPORIN, an Immunosuppressive agent.

THIOTEPA, used to treat lymphomas and tumors such as breast and ovary. It has also been used at high doses in combination chemotherapy with cyclophosphamide in patients with refractory malignancies treated with autologous bone transplantation.

PROPOSED to be listed as reasonably anticipated to be a human carcinogen

AZACITIDINE, used to treat acute leukemia.

p-CHLORO-o-TOLUIDINE and its HC1 salt, Used to produce azo dyes for cotton, silk acetate and nylon and as intermediate in production of Pigment Red 7 and Pigment Yellow 49. Also an impurity in and metabolite of the pesticide chlordimeform.

CHLOROZOTOCIN, used to treat cancers of the stomach, large intestine, pancreas and lung; melanoma; and multiple myeloma.

DANTHRON, used as a laxative and as an intermediate in the manufacture of dyes.

1,6-DINITROPYRENE. Not used deliberately, but detected in ambient atmospheric samples and as a constituent of diesel exhaust.

1,8-DINITROPYRENE. Same as above.

DISPERSE BLUE 1, used as an anthraquinone-based dyestuff in hair colors and in coloring fabrics, plastics

FURAN, used as an intermediate in the synthesis and production of other organic compounds.

o-NITROANISOLE, used as a precursor in the synthesis of o-anisidine which is used in the manufacture of over 100 azo dyes.

6-NITROCHRYSENE. Not used commercially, but detected in ambient atmospheric samples.

1-NITROPYRENE. Not used commercially, detected in ambient atmospheric samples and as a constituent of diesel and gasoline engine exhaust.

4-NITROPYRENE. Not used commercially, detected in ambient atmospheric samples.

1,2,3-TRICHLOROPROPANE, used as a polymer crosslinking agent, paint and varnish remover, solvent and degreasing agent. It has been found as an impurity in certain nematicides and soil fumigants and has been detected in drinking and ground water in various parts of the United States

The substances have been through two outside reviews and one internal review.