A nested case-control study of brain tumors among employees at a petroleum exploration and extraction research facility.

Work-related exposures potentially associated with a cluster of brain tumors at a petroleum exploration and extraction research facility were evaluated in a nested case-control study. Fifteen cases were identified in the original cohort and 150 matched controls were selected. Odds ratios (ORs) for occupational exposure to petroleum, radiation, solvents, magnetic fields, and work activities were near or below 1.