Retrospective determination of the cumulative asbestos fibre dust dose ("fibre years") of employees

Status:

completed 12/1996

Aims:

Asbestos is carcinogenic in man. The inhalation of asbestos fibres may lead not only to asbestosis, but also to lung cancer, laryngeal cancer, or a pleural mesothelioma. Owing to its wide range of applications, asbestos was used in over 3,000 different products up to 1980. From the mid-1960s up until the end of the 1970s, the Federal Republic of Germany imported an average of 170,000 tonnes of asbestos each year (German Democratic Republic: up to 70,000 tonnes per year). Increasingly strict bans on manufacture and use from the end of the 1970s onwards and the ensuing increased use of asbestos substitutes resulted in the consumption of asbestos in the Federal Republic of Germany dropping to its current effectively zero levels. Despite this satisfying development, cases of cancer due to asbestos continue to occur, as its latent period lies between 10 and a maximum of 60 years. Studies have demonstrated a link between the inhaled asbestos fibre dose (dose in "fibre years" = fibre concentration x duration of impact) and the risk of lung cancer. Up until 1992, such cases of lung cancer were recognized as being due to asbestos and corresponding compensation made when they were accompanied by asbestosis or disease of the pleura attributable to asbestos dust. An amendment to the German Occupational Diseases Ordinance has added a third alternative for compensation for asbestos-induced lung cancer, namely in cases where an asbestos fibre dose of at least 25 fibre years can be demonstrated. This alternative is dependent upon the availability of adequate, reliable exposure data for the widest possible range of activities involving contact with asbestos. A uniform investigation principle and corresponding procedures must also be in place. A working group involving a number of BGs (Institutions for statutory accident insurance and prevention) is to collect, survey, assess and provide suitable exposure data and to draw up a concept for calculation of the asbestos fibre dose of employees.

Activities/Methods:

The "Fibre years" working group set up by the German Federation of the BGs is to obtain exposure data in conjunction with individual BGs, and to draw up a concept for investigation. A total of around 27,000 data records in the "DOK-MEGA" database of the BG Institute for Occupational Safety (BIA), which documents measurement data on exposure to hazardous substances at the workplace, were surveyed, supplemented by a literature survey, and evaluated. An inventory of asbestos exposure data classified by occupational activity was created from the available information. Detailed instructions were formulated for retrospective investigation of the asbestos fibre dose.

Results:

The concept for investigation and calculation of the asbestos fibre dose of employees and the body of data processed by the project can be found in the Report on Occupational Diseases entitled "Fibre years". Application of the report guarantees that a clear and consistent procedure is followed for fibre-year calculations. As no hard exposure data are available in the majority of cases and the work situations can no longer be reproduced, the inventory of exposure data is of particular importance. The available documentation is updated continuously by the "Fibre years" working group. The "Fibre years" Report on Occupational Diseases is now in its forth edition (1/2007) (BGIA Project 2061 "Revision of the "fibre years" report (cumulative asbestos fibre dose)).

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