During the later part of World War I, it was proposed to make Avonmouth the UK centre of production of dichloroethyl sulphide, also known as mustard gas. However, its production was against the Hague Conventions of 1899 and 1907, which explicitly forbade the use of "poison or poisoned weapons" in warfare. Under the cover of the Official Secrets Act, the Ministry of Munitions under its then Minister Winston Churchill nationalised many small smelting works under the new National Smelting Company (NSC). Before the outbreak of WW1, much of Britain's zinc had originated in Australia, but had been smelted in Germany. The NSC was therefore publicly commissioned to build a new zinc smelting works and sulphuric acid plant at Merebank, Avonmouth.