Ibaraki Gov. Masaru Hashimoto asked the national government Wednesday to help deal with a contaminated well in the town of Kamisu.
The well's water is suspectof containing chemical compounds derived from organic arsenicals produced by the Imperial Japanese Navy for use as poison gas.
An investigation was launched by the prefectural government after a local woman and her child complained of numbness in their limbs. Levels of arsenic 450 times above government standards were detected in water drawn from the well used by the family.
During a meeting with Environment Minister Shunichi Suzuki at the ministry, Hashimoto asked the national government for its cooperation in further investigations, and Suzuki expressed his support, officials said.
Prefectural officials believe the water was contaminated by poison gas chemicals abandoned by the Imperial navy after World War II. The navy had a chemical laboratory in the area.
A prefectural government committee concluded it is likely the chemical compound was the kind used to produce sneeze gas, which induces sneezing and vomiting to disrupt the fighting capability of enemy soldiers.
The Kamisu woman and her child developed their symptoms in August and have since been treated at a hospital in Tsukuba, Ibaraki Prefecture.
The prefectural government announced the results of the local contamination probe March 20, three days after prefectural health authorities received a request from the Tsukuba hospital to investigate.