Report Alleges Chemical Arms Atrocities by Japan in WWII

Associated Press

Japan operated a secret chemical-weapons factory during World War II, bombed China with poison-gas grenades and tested poison on prisoners of war, including Americans, a new report charges.

The article in the October issue of the Chicago-based Bulletin of the Atomic Scientists also contends the U.S. government knew about Japan’s use of chemical weapons but failed to prosecute Japanese officers at the Tokyo war crimes tribunal in 1946.

The report’s author, Yuki Tanaka, speculated the U.S. government decided against prosecuting because it wanted to learn from Japan’s knowledge of bacteriological warfare.


“The use of chemical weapons (by the Japanese) was covered up by the U.S. government,” Tanaka said Saturday.

Neither the Japanese nor U.S. governments would respond to the report in the Bulletin, a monthly magazine founded in 1945 and supported by scientists concerned about the implications of nuclear weapons development.

Tanaka, a lecturer in Japanese at the University of Adelaide in Australia, drew on newly discovered Japanese war documents, his own interviews and previously published material to piece together the account, said Len Ackland, the Bulletin’s editor.

Tanaka said his research was prompted partly by the Japanese government’s longtime insistence that it never used chemical weapons in World War II.

He said his research showed that Japan built a factory for chemical weapons on Okunoshima, one of dozens of tiny islands in the Inland Sea. To help keep the factory secret, Tanaka contends, the Japanese government erased the island from maps in 1939.

The factory operated from 1929 until the end of World War II, Tanaka said, when it was destroyed at the direction of Allied officers. The plant manufactured chemicals including mustard gas, nausea gas and hydrocyanic acid gas for use against China, the report said.


In one test, Chinese prisoners had to drink a liquid form of a chemical weapon; in another, some of the liquid was dropped in the eyes of a prisoner, Tanaka said.

No Details on Americans

The article gave no details on the tests on Americans.

Atrocities committed during the Japanese invasion of China in 1937 have long been a source of controversy between the two countries.

Chinese army records allege that at least 2,000 Chinese were killed and 35,000 injured by Japanese chemical weapons, Tanaka’s report said.

In his article, Tanaka contends that U.S. Col. Thomas Morrow, a law officer assigned to investigate Japanese war crimes, uncovered evidence of Japan’s use of chemical weapons and wrote two reports about it.

But Tanaka said Morrow “was summoned home abruptly” from Tokyo in the early stages of the war crimes trials, “and the issue was dropped, possibly because the U.S. government was interested in keeping information relating to biological and chemical warfare for its own use.”