Cancer risk in carbon electrode workers: an overview of epidemiological evidence

Carbon or graphite electrode manufacturing may lead to exposure to polycyclic aromatic hydrocarbons, some of which are considered human carcinogens. To provide comprehensive evidence on cancer risk, we have considered five cohort studies from the USA, France, Sweden and Italy, including about 6,500 workers and 80,000 man-years at risk. In two studies providing data on incidence, 52 incident cases of all neoplasms were reported versus 56.28 expected, corresponding to a standardized incidence ratio (SIR) of 0.92. There were nine cases of lung cancer (SIR=0.91) and three of urinary cancers (SIR=0.81). Four studies gave data on mortality. Overall, 853 deaths were observed versus 1,065.2 expected, corresponding to a standardized mortality ratio (SMR) of 0.80 (95% confidence interval, CI, 0.75-0.86). There were 269 deaths from all neoplasms, versus 292.1 expected (SMR=0.92, 95% CI 0.81-1.04), 82 deaths from respiratory cancers versus 95.8 expected (SMR=0.86), and 15 deaths from bladder and urinary cancers versus 12.7 expected (SMR=1.18). None of these estimates were significant, and for none of the other cancer sites there was evidence of excess risk. Thus, epidemiological data allow excluding any appreciable risk of cancer--in particular of the respiratory and the urinary tract--in carbon electrode workers.