Mortality of men employed in the British steel industry: a prospective study. Final report on CEC Contract 6244-008/8/108

Progress is reported on a continuing prospective study of mortality in the British steel industry. The inception date for the follow-up is August 196?, and all the men involved had been working in the industry for at least four and a half years previously.A provisional description of the cohort being studied shows that the 88 000 men concerned had been employed at 61 steel works in Britain. Nearly a third of them came from eight steel works in Wales, and seven per cent were from 15 works in Scotland. Two works, in South Humberside and Lancashire, provide nearly one tenth of the data.Some occupational history information, referring to jobs before 1972/73, is available for nearly half of the identified cohort, but these data are incomplete. They have been verified and up-dated to 1976 only for men who had been employed at coke oven departments inAbout 73 per cent of the men were still employed at the works concerned during the period when the data were collected (1972/73) Records of interviews, conducted by Works medical staff, are available for 24 000 of them (38 percent). These records include answers to questions on respiratory symptoms and smoking habits as well as previous occupations.An analysis of jobs being done by more than half of the men still employed at the time the data were collected shows that 38 percent were then craftsmen, skilled or semi-skilled, or labourers. Hot rolling mill operators accounted for 13 percent of the group; eight percent were working in steel melting shops; and five percent were on blast furnaces. Cold reduction mill operatives and ancillary workers accounted for another eight percent.Follow-up of the cohort is maintained through the National Health Service Central Register for all men who have left the industry, and by periodic interrogations of the Steel Corporation’s pensions computer files for the remainder. Copies of death certificates are obtained for all who die. At least 8 000 deaths were recorded in approximately 10 years, to 1977.Statistical analyses of these results will take place as part of the second phase of the project and on the basis of up-dated and verified files describing the cohort.A detailed study has been made of mortality, over a nine-year period, in a sub-group consisting of 2 760 men who had worked for at least 19 months at any of 14 coke oven.departments. Special procedures were used to verify and up-date the occupational history records for these men up to 1976. The regionally-adjusted Standardised Mortality Ratio (SMR) was 90 percent for deaths from all causes and 126 percent for deaths attributed to lung cancer. Comparisons with published statistics for industrial workers in England and Wales show similar unexpectedly high proportional lung cancer mortality: the SMR’s were 83 and 104 percent for all causes and lung cancer respectively. These results are similar to those found in an independent parallel study of 4 000 men who had been employed in 1967 at 13 coke works controlled by the National Coal Board. In both investigations there were statistically significant variations in mortality patterns between works, which were not explicable in terms of differential smoking habits as recorded for more than a third of the men concerned.Lung cancer mortality in a sub-group whose occupational history records referred to specific ovens jobs prior to 1967 was no higher than that found among men with no history of work on the ovens. The Coal Board study gave the same result. However, sub-division of the steel industry’s “”ovens work”” group showed that men who had spent five years or more on the ovens had about 20 percent higher lung cancer mortality than all the coke workers considered.The results are compared with American reports. It is concluded that an occupationally related lung cancer hazard has been demonstrated for British coke workers at some plants but that the excess risk is considerably less than that found in the USA. The continuing work, based on longer follow-up periods, may help to explain the reasons for the difference observed. “”