Objective: The authors studied the mortality by lung cancer in telephone linemen exposed to asbestos at low levels during installation of telephone cables.
Methods: Three hundred eight lung cancers deaths were identified in the cohort. Exposure to asbestos and to other occupational carcinogens was assessed using a job-exposure matrix.
Results: The relative risk for lung cancer death associated with an estimated exposure of approximately 2 f/cc-years was 2.1 (95% confidence interval = 1.1–4.0) as compared with workers exposed to less than 0.5 f/cc-years. Mean annual exposure or exposure duration were not clearly related to lung cancer. Adjustment for other occupational lung carcinogens did not change this finding.
Conclusion: The observed mortality by lung cancer associated with asbestos exposure at low levels is higher than the prediction based on linear downward extrapolations from highly exposed occupational cohorts.