Malignant Mesothelioma in Australia (1945–1995)

Abstract

In Australia, more chrysotile than amphibole asbestos was mined until 1939. With the commencement of mining at Wittenoom, Western Australia in 1937, crocidolite dominated production, until final closure in 1966. New South Wales, the first State to mine asbestos, also produced the largest tonnages of chrysotile (until 1983) as well as smaller quantities of amphibole (until 1949). With the closing of the crocidolite mine at Wittenoom in 1966, Australian asbestos production and exports declined. Imports of chrysotile also started to decline. The main sources of raw asbestos imports were Canada (chrysotile) and South Africa (crocidolite and amosite). In addition to imports of asbestos fibre, Australia also imported many manufactured asbestos products, including asbestos cement articles, asbestos yarn, cord and fabric, asbestos joint and millboard, asbestos friction materials and gaskets. The main sources of supply were the United Kingdom, U.S.A., Federal Republic of Germany and Japan. In Australia over 60% of all production and 90% of all consumption of asbestos fibre was used by the asbestos cement manufacturing industry. From about 1940 to the late 1960s all three types of asbestos were used in this industry, crocidolite then being phased out. Much of this industry output remains in service today in the form of fibro houses and water and sewerage piping. By 1954 Australia was number four in the Western world in gross consumption of asbestos cement products, after U.S.A., U.K. and France, and clearly first on a per capita basis. From World War II to 1954, 70 000 asbestos cement houses were built in the state of New South Wales alone (52% of all houses built). In Australia as a whole, until the 1960s, 25% of all new housing was clad in asbestos cement. Exposures in the past were very high in some industries and jobs [e.g. 25 million particles per cubic foot (150 fibres ml) in asbestos pulverisors and disintegrators in the asbestos cement industry; up to 600 fibres ml in baggers at Wittenoom]. Australia still imports about 2000 tonnes a year of chrysotile fibre and about $A13.5m worth of asbestos products a year, over half as friction material but also fabricated yarn, fabric, jointing, gaskets, millboard and asbestos cement products. Handling of asbestos in place and removal operations are subject to a strict National Code of Practice. A series of regulations adopted in the late 1970s and early 1980s by the various states now impose exposure limits of 0.1 fibre mP 1 for crocidolite, amosite and mixtures and 0.1-1.0 fibre ml for chrysotile (TWA 8 h membrane filter method light microscopy, WHO fibres).