A study of a sample of chest radiographs from the Health and Safety Executive’s survey of asbestos workers. Final report on HSE contract 1/MS/126/553/79S/126/553/79

Objectives: Results are reported of a study of nearly 6 000 chest radiographs from more than 3 600 British workers who were occupationally exposed to asbestos for some time at least in the interval between 1 January 1971 to early 1978. The radiographs were a sample of those collected in 1971 and after as part of the Health and Safety Executive’s Survey of Asbestos Workers; 45% of the material studied was from individuals who had been exposed to asbestos already before 1971. The main objectives of the work were to estimate the prevalence of Various radiological signs of asbestos-related disease in workers who had not been occupationally exposed to asbestos before the introduction in 1971 of the Government’s (1969) Asbestos Regulations, and to compare the incidence and progression of the radiological signs in this group with the experience of others who had been exposed before 1971.Sampling plan: A computer tape identifying 26 471 individuals who had taken part in the surveys was used to generate requests for radiographs from the factories where the surveys had been conducted. Attention was restricted to 24 429 persons whose recorded occupational histories indicated employment in not more than one of 10 “”industry sectors”” into which all asbestos-related jobs had been classified. The requests to the factories were for all films from persons first exposed to asbestos after 1971 who had been surveyed since then on at least two occasions. Additionally, all available post-1971 films were requested from random samples of individuals, stratified by industry sector, as follows: 15% of those with no exposure before 1971 and for whom only one film was available; 41% of those with some known exposure before 1971 and for whom three or more post-1971 films were available; and 10% of those with some known exposure before 1971 and for whom only one or two post-1971 films were available. “”