Mortalities of workers at the Nitro plant with exposure to 2-mercaptobenzothialzole.
OBJECTIVE
An update of a study of workers exposed to 2-mercaptobenzothiazole (MBT) at a rubber chemicals plant in Nitro, West Virginia is reported. The earlier study found high rates of lung cancer, prostate cancer, and bladder cancer in these workers who also had potential exposure to 4-aminobiphenyl (PAB), a potent bladder carcinogen.


METHODS
This cohort mortality study examines the mortalities of 1059 full time white male production workers employed at the plant from 1955 to 1977. A detailed exposure assessment was done on the 600 workers with exposure to MBT. Nine years of additional follow up to the previous study are added.


RESULTS
It was found that MBT workers have expected rates of lung (standardised mortality ratio (SMR) = 1.0 95% confidence interval (95% CI) 0.7 to 1.5) and prostate (SMR = 0.9, 95% CI 0.2 to 2.3) cancer. There was an excess of bladder cancer among MBT workers who had definite exposure to PAB (SMR = 27.1, 95% CI 11.7 to 53.4), and MBT workers with potential exposure to PAB (SMR = 4.3, 95% CI 1.4 to 10.0). However, there were no deaths from bladder cancer among workers with no exposure to PAB (SMR = 0.0, 95% CI 0.0 to 24.7), although there were only 0.2 deaths expected.


CONCLUSIONS
The potential confounding of exposure to an unknown portion of PAB in the MBT workers makes it impossible to evaluate risk of bladder cancer in this population at this time. However, exposure to MBT does not seem to increase the risk of most cancers including cancers of the lung and prostate.
Collins
J J
JJ
j.collins@Solutia.com
Strauss
M E
ME
Riordan
S G
SG
D000368:Aged; D000611:Aminobiphenyl Compounds / Q000009:adverse effects*; D002423:Cause of Death; D002617:Chemical Industry; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000139:chemically induced / Q000401:mortality; D008297:Male; D009369:Neoplasms / Q000139:chemically induced / Q000401:mortality*; D009784:Occupational Diseases / Q000139:chemically induced / Q000401:mortality*; D016273:Occupational Exposure / Q000009:adverse effects*; D011471:Prostatic Neoplasms / Q000139:chemically induced / Q000401:mortality; D012408:Rubber / Q000009:adverse effects; D013438:Sulfhydryl Compounds / Q000009:adverse effects*; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000401:mortality; D014903:West Virginia / Q000453:epidemiology
D000611:Aminobiphenyl Compounds; D013438:Sulfhydryl Compounds; D012408:Rubber