“From 1928 until its closure in 1986, the site [Homesbush Bay] was used for the manufacture of a wide range of highly toxic chemicals, including timber preservatives, herbicides, pesticides and plastics. For the latter half of its operating life, the site was owned by union Carbide Australia ltd... From 1949 until 1976, the site was used to manufacture the herbicides 2,4,5-t and 2,4-D, the ingredients for Agent Orange that was used as a defoliant in the Vietnam War. As a result of both chemical manufacturing and the use of contaminated fill for reclamation, soil and groundwater on the site were highly contaminated by various chemicals, including dioxins... While the heavily contaminated former union Carbide site has been extensively remediated, dioxins from the site have spread throughout the sediments at the bottom of Sydney Harbour... Dioxins from the contaminated sediments enter the marine food chain and are accumulated in fish, prawns and other organisms. the only practicable means to ‘remove' the contaminants from the marine food chain is to allow other, clean sediments to cover the contaminants. For much of the harbour, this process will take decades. Fishing bans have been in place around Homebush Bay since 1989, and were extended to parts of the Parramatta river in 1990.”