Japan's toxic past resurfaces.

Chemical weapons stored by the Japanese army at the end of World War II pose greater health risks than previously thought, according to a recent report by Japan's Ministry of the Environment. The study found chemical weapon stockpiles or damage caused by shells at 81 locations around the country's shoreline, compared with 8 locations noted in a 1973 government report. In all, states the new report, 138 locations had at some point been the site for the manufacture/storage, disposal, discovery, or other issue related to poison gas shells.

Wartime Japan produced an estimated 7,000 tons of chemical weapons, according to the Associated Press (AP). After the war, the military buried over 3,800 tons at locations around the island's shores, according to the 1973 survey. At that time, officials said they knew of no other chemical stockpiles. Many documents on the military's use of chemical weapons were destroyed after the war ended.

The new study reviewed data obtained from various government ministries, local and regional agencies throughout the country, and reports from the general public in an effort to update the 1973 survey. A summary of the recent report noted that the 138 sites named in the report included 114 locations on land as well as 29 at sea (5 locations fell under both categories).

The main chemicals found were mustard gas and an arsenic-based blistering agent called lewisite. Both cause respiratory irritation, vomiting, and skin blisters. Other chemicals were found as well: chlorodiphenyl (which can cause liver damage and irritate the eyes and skin), chloroacetophenone (tear gas), phosgene (a colorless gas that can cause weakness lasting weeks or months), hydrogen cyanide (a colorless gas with a slight almond-like odor that at low-level exposures can cause breathing difficulties, heart pains, vomiting, and headache), and trichloroarsine (which affects respiration and can cause cancer). The report stated that the current understanding of the health effects of these chemical weapons is inadequate.

The report named four sites in the cities of Hiratsuka, Samukawa, Kamisu, and Narashino, all near Tokyo, that require immediate action to protect Japan's residents, and listed other sites where further research is needed before remediation can begin. "We have to take appropriate measures," said chief cabinet secretary Yasuo Fukuda when the study was released, according to a 28 November 2003 AP report. He added that government agencies would respond quickly, but offered no details.

The report's November 2003 release followed months of speculation and several incidents where the chemicals contaminated soil and water. In September 2002, in Samukawa, a road construction crew struck a buried cache of bottles containing mustard gas and lewisite near a residential area. The crew reported sore throats and blisters on their arms and legs. In April 2003, another cache was discovered in Kamisu, after a local physician treated a woman and her child for arsenic poisoning. Over a dozen residents reported similar problems. Officials found arsenic in local wells at concentrations 450 times the government safety standard, according to a May 2003 report by U.S. Water News Online. During the war, Kamisu housed a military airfield and laboratory.

In the new report, Kamisu is listed as a "disposal" and "other" site, while Samukawa is listed under the categories of "manufacture/storage," "disposal/remains," and "discovery/possible damage." At the sites in Narashino and Hiratsuka, environmental studies and procedures to ensure safety during land-use changes are needed, the report concluded. It noted 16 cases in other regions where reliable reports confirmed the presence of weapons presence, but without specific locations.

Some Japanese groups have sought to open records that might contain more information. Yoshiaki Yoshimi, a professor at Chuo University, told the Kyodo News on 23 March 2004 that the country's Defense Agency still has thousands of documents on the wartime military that have not been released. He urged that these be disclosed to avert further disasters.

The weapons legacy has also become an international issue with China, where Japanese forces buried an estimated 700,000 chemical warheads in the northeast, according to Keiichi Tsuneishi, a professor of history at Kanagawa University. Under a 1997 treaty, Japan must safely dispose of these chemicals. After a Chinese construction worker was killed when his crew unearthed canisters of mustard gas on 4 August 2003, Japan agreed to pay US$2.7 million in compensation, The China Daily reported in October. Beijing has pressed Japan to accelerate the cleanup efforts throughout China.