Techniques for tracing past employees. An example from an asbestos factory.

During the past 20 years there has been increasing concern about the long-term effects of occupational exposure to a wide range of substances. Different techniques have been developed to assist in the retrospective study of whole populations exposed to such hazards. Doll (1952) used a gas company's pension records to identify an occupational risk of lung cancer; he also (Doll, 1955) used the personnel records of an asbestos factory to identify the risk of lung cancer among its male workers. Case and Bidstrup (1956) measured the mortality rate of 723 chromate workers who had been clinically surveyed. Case, Hosker, Macdonald, and Pearson (1954) obtained nominal rolls of workers employed in 21 firms in the dyestuffs industry and used hospital records and death registers to establish the incidence of bladder tumour. In the United States, Mancuso (1959) and Mancuso and Coulter (1963) have used a method of tracing an industrial population which is quite independent of local factory records. The Bureau ofOld Age and Survivors Insurance (BOASI), a department of the Federal Government, keeps records of nearly all employed persons in order to administer social security benefits. The record of the worker can be related to the employer. By using BOASI records they obtained data relating to those employed at a certain asbestos factory in 1938 and 1939 and studied the mortality of these cohorts. In this paper it will be shown how the national registers and local records can assist in tracing the fate of past employees at an asbestos factory. It is hoped to determine the mortality rates from various diseases and study the influence of length of exposure, of exposure to different types of asbestos, and of different jobs. The techniques used can be applied in tracing any industrial population.