Monitoring of aromatic amine exposures in workers at a chemical plant with a known bladder cancer excess - response.
J Natl Cancer Inst 1997 May; 89(10):735-736
We have published responses in this Journal to earlier letters regarding our study of excess bladder cancers in a chemical-manufacturing plant. To summarize our earlier responses, o-toluidine, which has induced bladder tumors in rats, is used in quantities of 7.2 million pounds per year in the manufacture of an antioxidant at the plant. 4-Aminobiphenyl, which Dr. Freudenthal and Mr. Anderson claim is the cause of the bladder cancers, was present at less than 1 part per million in three of nine current bulk samples of process chemicals used at that plant. Furthermore, average levels of adducts to 4-aminobiphenyl do not differ between workers employed in the department where the antioxidant is manufactured and unexposed control subjects. We believe that 4-aminobiphenyl levels in the past would not be orders of magnitude greater than what they are currently. Therefore, the weight of the evidence favors o-toluidine as the major etiologic agent in the bladder cancer excess. Freudenthal and Anderson state, "There is documentation that workers were exposed in the 1950s and early 1960s to diphenylamine. Diphenylamine often contains 4-aminophenyl," However, as we have stated before, our review of historical plant records indicated that diphenylamine was an additive to a product that was manufactured intermittently from 1972 to 1985. Freudenthal and Anderson incorrectly quote Donald Sherman, M.D., Corporate Medical Director for the affected plant, when they state that he informed NIOSH that 4-aminobiphenyl was present in the plant from 1957 to mid-1966. What Dr. Sherman did say in a letter dated May 23, 1996 to NIOSH was, "We postulate that something else occurred in the Niagara Falls plant process between start-up in 1957 and the mid- 1960s that was responsible for the bladder cancers in our workers. We believe that the probable cause was 4-aminobiphenyl, created in the early process at levels which initiated the cancers but were later reduced by operational changes in the '60s and '70s. We cannot state that conclusively, as there are no exposure data from that period, but we believe it to be a more plausible hypothesis."
Amines; Aromatic-hydrocarbons; Bladder-cancer; Bladder-disorders; Urogenital-system-disorders; Endocrine-system-disorders; Chemical-properties; Animal-studies; Antioxidants; Laboratory-animals
Elizabeth M. Ward, Ph.D., Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, Robert Taft Laboratory, 4676 Columbia Parkway, Cincinnati, Ohio 45226
95-53-4; 92-67-1; 122-39-4
Journal of the National Cancer Institute