title: Cancer mortality and incidence among a cohort of benzidine and dichlorobenzidine dye manufacturing workers.
abstract: BACKGROUND
  Benzidine is classified as a definite human carcinogen and dichlorobenzidine as a probable human carcinogen.
  
  
  METHODS
  A cohort study of 538 workers potentially exposed to benzidine and/or dichlorobenzidine from a single chemical manufacturing facility was conducted. Social Security records were used to identify all employees who worked at the facility from 1960 to 1977. Vital status was determined through 2001 and cancer incidence through 2002.
  
  
  RESULTS
  A total of 22 bladder cancer cases were identified. For three individuals, bladder cancer was the underlying cause of death. Increased standardized mortality ratios (SMRs) were found for all cancer 1.54 (95% CI 1.04-2.19), bladder cancer 8.34 (95% CI 1.72-24.78), and lymphohematopoietic cancer 2.84 (95% CI 1.04-6.18). The standardized incidence ratio (SIR) for bladder cancer was 6.85 (95% CI 4.30-10.4). Only one case of bladder cancer was identified among the workers who were exposed to dichlorobenzidine only. However, an increased risk for lymphohematopoietic cancer was found among these dichlorobenzidine only workers (SMR 6.62 (95% CI 1.37-19.36)).
  
  
  CONCLUSIONS
  This study confirms the high risk of bladder cancer among benzidine exposed workers even years after exposure has ceased, and raises suggestive evidence of increased risk to lymphohematopoietic cancer from exposure to benzidine or dichlorobenzidine.
authors.affiliation: Department of Medicine, Michigan State University, 117 West Fee Hall, East Lansing, Michigan 48824-1316, USA. Rosenman@msu.edu
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Rosenman
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: Reilly
mesh_terms: D000328:Adult; D001560:Benzidines / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D002423:Cause of Death; D002617:Chemical Industry; D015331:Cohort Studies; D004396:Coloring Agents / Q000633:toxicity*; D005260:Female; D019337:Hematologic Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D009784:Occupational Diseases / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000453:epidemiology
chemical_list: D001560:Benzidines; D002273:Carcinogens; D004396:Coloring Agents; C029876:benzidine