Wittenoom is a former mining town and a declared contaminated site, 1,420 kilometres (880 mi) north-north-east of Perth, in the Hamersley Range in the Pilbara region of Western Australia. The declared contaminated site comprises 46,840 hectares (115,700 acres), making it the largest contaminated site in the southern hemisphere, an area nearly 1⁄5 the size of the Chernobyl exclusion zone area. The Government of Western Australia "strongly advises against all travel through Wittenoom and the surrounding areas." The area around Wittenoom was mainly pastoral until the 1930s when mining for blue asbestos began. By 1939, major mining began in Yampire Gorge, which was closed in 1943 when mining began in Wittenoom Gorge. In 1947, a company town was built and, during the 1950s, it was the Pilbara's largest town. The peak population, as recorded by the Australian census conducted on 30 June 1961, was 881 (601 males and 280 females). During the 1950s and early 1960s, Wittenoom was Australia's only supplier of blue asbestos.