ARSENIC was the main cause of a high number of people contracting lung cancer after working at a notorious tin smelting works in East Yorkshire, a report has revealed.
The study says the chemical was the "principal occupational factor" behind the fact that workers at Capper Pass were 50 per cent more likely to contract lung cancer.
Another factor was the higher-than-average proportion of smokers in the workforce at the plant at Melton, west of Hull, which closed in 1991 amid a storm of accusations about health and safety.
Principal author of the study, Prof Steve Jones, said they examined the relationship between lung cancer mortality and estimates of exposure to substances at Capper Pass, including arsenic – which occurs in copper ores as well as process residues from other substances handled by the plant – cadmium and polonium-210. Estimation of exposure was based on personnel record cards and a database of 20,000 results from air quality measurements in all the major areas of the plant by staff and the Health and Safety Executive.
A summary of the report, a follow-up to a study into lung cancer at the plant overseen by the late Sir Richard Doll, and commissioned by Capper Pass' former owners Rio Tinto, adds: "Occupational exposure to arsenic accounts for about half of the excess mortality in lung cancer that we found in our original study.
"The remainder of the excess may reflect a difference between the baseline incidence of lung cancer in the cohort and that in the population of England and Wales as a whole. The most likely cause of any such difference would be a greater proportion of smokers in the cohort as compared to the average proportion of smokers in the cohort as compared to the average proportion in England and Wales."
Prof Jones confirmed yesterday that the most likely explanation for the excess was arsenic exposure.
Campaigners were not satisfied. Retired health visitor Rilba Jones said: "It doesn't explain the whole picture and what happened downwind of the chimney."
Interim payments have been made to the relatives of 29 workers who had lung cancer.