The existence of a detailed report documenting how chemical weapons were used by the Imperial Japanese Army in China has been confirmed for the first time, a Japanese historian said Sunday.

The official report, compiled by a frontline poison gas battalion posted in northern China, recorded that the unit used munitions containing a blister agent and a sternutatory agent in 1939 during the Second Sino-Japanese War, according to historian Seiya Matsuno.

The blister agent inflamed the skin and mucous membranes, and the sternutatory agent caused extreme pain in the respiratory system.