Kenneth Olden, Ph.D., Director of NTP and NIEHS, said, "The report identifies public health hazards but does not in-and-of-itself restrict substances. Never-the-less, regulatory agencies and Congress take note and may take action in cases where the substances are not already regulated.
"The report," he continued, "is not necessarily a condemnation, in that some substances such as the newly listed transplant drug cyclosporin have health benefits, when properly used, that can far exceed their potential risk."
Cyclosporin's labeling already calls attention to studies indicating a potential cancer risk. The drug is used to help prevent rejection of a transplanted kidney or other organ by its new host.
A second prescription drug for a life-threatening condition, thiotepa, is also newly listed as a known human carcinogen. It was previously listed as an anticipated human carcinogen.
The Report on Carcinogens is prepared by the National Toxicology Program, which is headquartered at the National Institute of Environmental Health Sciences in Research Triangle Park, N.C. The reports are prepared with the help of NIEHS and NTP-participating agencies -- the National Cancer Institute, the Food and Drug Administration, the National Institute for Occupational Safety and Health, the Environmental Protection Agency, the Agency for Toxic Substances and Disease Registry, the Consumer Product Safety Commission and the Occupational Safety and Health Administration, as well as the NTP's Board of Scientific Counselors.
Newly listed as known human carcinogens:
CYCLOSPORIN, an immunosuppressive drug.
THIOTEPA, a drug used to treat lymphomas and tumors of the 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.
Newly listed as Reasonably Anticipated to be Human Carcinogens:
AZACITIDINE, a drug 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, a drug used to treat cancers of the stomach, large intestine, pancreas and lung; melanoma; and multiple myeloma.
DANTHRON, or dantron, a laxative removed from the market several years ago when tests were published indicating it caused cancer in laboratory animals. It is also an intermediate in the manufacture of dyes.
1,6-DINITROPYRENE. No commercial uses but is detected in ambient atmospheric samples and as a constituent of diesel exhaust.
1,8-DINITROPYRENE. Also in diesel exhaust and air samples.
DISPERSE BLUE 1, used as an anthraquinone-based dyestuff in several semi-permanent hair dyes and also in coloring fabrics and plastics
FURAN, used as a chemical 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 more than 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 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 also been detected in drinking and ground water in various parts of the United States
The newly listed substances have been through three scientific peer reviews, one of which was by a subcommittee of the NTP Board of Scientific Counselors in an open meeting with comment provided from industry and public interest groups and there was a period for public review and comment.
George Lucier, Ph.D., director of the Environmental Toxicology Program at NIEHS, said, "A great many scientists have worked on the studies and reviews that produced this document, which is an important part of our national effort to protect the public from potentially dangerous exposures."
The 8th Report on Carcinogens Summary is accessible now from the NIEHS Environmental Health Information Service at: http://ehis.niehs.nih.gov/ or from the NTP Home Page at http://ntp-server.niehs.nih.gov/
Printed copies of the report in full, or the summary (which contains the same information except for information on related regulations by regulatory health agencies) will be available later. Either can be ordered by contacting the NIEHS Environmental Health Information Service (EHIS) 1-800 315-3010, Attn: Order Processing, P.O. Box 12510, Research Triangle Park, NC 27709-2510, fax number (919) 541-0763, email: firstname.lastname@example.org