Although Australia has never produced chemical weapons, it did stockpile chemical weapons sourced from the United States and Britain. Chemical weapons known to have been stockpiled included mustard gas, phosgene, lewisite, adamsite and CN gas. Some of the stockpiled weapons in the form of mortar and artillery shells, aerial bombs and bulk agents were sent to New Guinea for potential use against Japanese tunnel complexes. No actual use of the weapons was made although there were many trials using 'live' chemical weapons (such as shown in the adjacent picture). After World War II, the chemical weapons were disposed of by burning, venting (for phosgene) or by dumping at sea. Some 21,030 tons of chemical weapons were dumped in the seas off Australia near Brisbane, Sydney and Melbourne. This has been covered in a Defence report by Geoff Plunkett. A complete history of Australia's involvement with chemical weapons – titled Chemical Warfare in Australia – has been published in book form by the Army History Unit (Defence Department) in 2013 (2nd Edn) Again it is authored by Geoff Plunkett . A stockpile of 1,000 pound phosgene bombs was discovered at Embi Airfield, Papua in 1970 and disposed of by Australian Army personnel, and, up to 1990, drums of mustard gas were still being discovered in the bush where they had been tested. Another stockpile of chemical weapons was discovered at Maxwelton, Queensland in 1989. Australia signed the Chemical Weapons Convention in January 1993 and ratified it with the Chemical Weapons (Prohibition) Act in 1994. Nuclear weapons Australia does not currently have nuclear weapons and has never had its own nuclear weapons, although several federal governments have investigated the idea and conducted research into the question. Australia investigated acquiring tactical nuclear weapons from the United Kingdom or the United States as early as 1956 when Athol Townley, Minister for Air, wrote to Philip McBride, Minister for Defence, recommending the acquisition of tactical nuclear weapons to arm Australia's English Electric Canberra bombers and CAC Sabre fighters. Air Chief Marshal Frederick Scherger and Minister for Air Athol Townley supported acquiring nuclear weapons, both for international prestige and because of the small size of the country's military. While Scherger's British and American counterparts were encouraging, the Macmillan and Eisenhower governments were not. Prime Minister Robert Menzies' government decided that domestic production would be too difficult due to cost and international politics. Australia hosted British nuclear