MORTALITY EXPERIENCE OF ONTARIO GLASS FIBRE WORKERS—EXTENDED FOLLOW-UP

A historical prospective mortality study was conducted at an insulating wool plant in Ontario, Canada, covering 2557 men who had worked for at least 90 days and were employed between 1955 and 1977. Our previous record described mortality between 1955 and 1977 and this paper extends the follow-up to the end of 1984; 157 deaths were found in the 97% of men traced. Mortality was compared by the person-years method with that of the Ontario population. Overall mortality was below that expected (Standardized Mortality Ratio, SMR=84). Cancer deaths were slightly raised, owing entirely to an excess in lung cancer. The 21 deaths from this cause give a significantly high SMR of 176. All but two of these cases occurred among ‘plant-only’ employees. However, the interpretation of these data remains difficult because the SMRs by length of exposure and time since first worked were not consistent with a causal relationship.