Here was an enemy known to possess a well developed chemical warfare organisational structure and ample chemical weapons and defensive equipment. Samples of their chemical weapons and protective equipment were captured in Papua New Guinea and brought back to Australia for analysis. From 1937 onwards the Japanese had also recently used these chemical (and biological) weapons against the Chinese in China. They had also spurned the only international control of such weapons, the Geneva Protocol of 1925. The Protocol banned the use of asphyxiating, poisonous or other gases in time of war. Although the initial use of chemical weapons was prohibited, the law did not prevent a nation either manufacturing or importing such weapons and thus reserving a capability for retaliatory strikes. Japan refused to sign the document.

With such a ruthless enemy at the doorstep Australia saw a deterrent chemical warfare stock as a key component of a defensive strategy to prevent their use. Although a signatory to the Geneva Protocol of 1925, Australia could justifiably import chemical weapons for the purpose of a retaliatory strike.