Case-control study of brain tumor deaths among employees at a chemical manufacturing plant.

Recent studies have reported an increased risk of death from primary intracranial neoplasms among employees in the petrochemical industry. One of them, a NIOSH/OSHA county-based case-control study, suggested a twofold risk for having ever been employed at the Texas Division of Dow Chemical U.S.A. Using the case-control approach, we compared 24 brain tumor cases among employees at this large, diverse chemical plant in Texas with two sets of age-, race-, and sex-matched controls to determine if a risk could be associated with job assignment in a particular process area, with presumptive exposure to a major process chemical, or with a number of other occupationally related and unrelated variables. Results implicated no specific area or chemical. The only significant findings were an elevated odds for being hired prior to 1950 and a negative correlation with employment greater than 10 years. Further, preliminary calculations of expected deaths from primary intracranial neoplasms among the employee cohort suggested there was no excessive risk.