Around 161,000 tonnes of blue asbestos was mined from Wittenoom by 7,000 mostly immigrant labourers before the mine closed in 1966. The mineral, also known as crocidolite, is the most fatal variety of asbestos, and Australia's National Health and Medical Research Council estimates that the final death toll among mine workers operation will rise to 2,000, on a par with Bhopal and Chernobyl in the first rank of industrial disasters.