Investigation of cancer incidence and mortality at a Scottish semiconductor manufacturing facility

Background We became aware of concern about cancer at a Scottish semiconductor manufacturing facility in 1998. Aim To compare cancer experience among current and former workers at the facility, with an appropriate comparison population, making use of any readily available exposure information. Method We obtained personnel and employment episode information from four sources within the company. Workers were flagged for death and cancer registrations at the National Health Service Central Register in Edinburgh. We constructed standardized registration and mortality ratios (SRRs and SMRs), using Scotland as the comparison, with and without an adjustment for deprivation. Results The main mortality analysis included 4388 workers, with a mean length of follow-up of 12.5 years. Overall mortality was substantially below that expected for men, and for women was slightly below expected. Total cancer registrations were close to expected levels for men and women. Four cancers produced noteworthy findings: malignant neoplasm of the trachea, bronchus and lung in women--deprivation adjusted SRR [95% confidence interval (CI), number of cases] 273 (136-488, 11 cases); malignant neoplasm of the stomach in women--adjusted SRR 438 (90-1281, three cases); and malignant neoplasm of the female breast--adjusted SRR 134 (82-206, 20 cases). The unadjusted SMR for male brain cancer was 401 (83-1172, three cases) and there was an additional non-fatal case. Conclusion These findings, particularly those relating to lung cancer, though inconclusive, point to the possibility of a work-related risk of cancer that justifies further investigation.