NANJING, China — High on a hill above an abandoned brickyard, a poisonous legacy of war lingers in this placid city.
In February 2000, a road construction team digging on Yellow Beard Mountain stumbled on a stash of chemical weapons left by Japanese forces when they pulled out of China at the end of World War II.
Unbeknown to the residents who went about life in its shadow, about 20,000 metal canisters lay buried atop the hill, full of toxic substances still capable of inducing vomiting in victims, damaging lung tissue and, in extreme instances, causing a painful death by suffocation from excess fluid in the lungs.
More than half a century since the munitions were stowed away, work finally wrapped up this month on unearthing and moving them to a special storage site. Eventually, technicians are to neutralize the harmful agents inside.
The size of the cache, experts say, is enough to put Yellow Beard Mountain near the top of the list of places around the world, including sites in England and France, where abandoned chemical weapons have been recovered and disarmed in recent times.
More startling is the fact that the stockpile in Nanjing represents just a tiny fraction of the chemical arms in China left behind by the retreating Japanese army.
The Japanese government, which is bound by international treaty to render harmless the abandoned ordnance, estimates that 700,000 of its chemical munitions are scattered across China; Beijing puts the figure at 2 million.
Either way, China is now home to the world's largest chemical weapons cleanup campaign at a time of new global scrutiny of unconventional warfare and its consequences.
The process of destroying the arms is extremely delicate and shows the challenge that could lie ahead for the U.S. and its allies if Osama bin Laden turns out to have amassed an arsenal of chemical weapons and if U.S.-led forces succeed in getting their hands on it.
The difficulty of the decommissioning project in China is compounded by the leftover weapons' age, condition, mixed content and sheer quantity.
"This is something that has been done before, but not on that scale," said Abu Talib, a chemical weapons expert in the United States. "Most of the chemical weapons around the world, you're talking [in the] hundreds and thousands--not such a huge pile."
Talib works at Mitretek Systems in Falls Church, Va., an organization being consulted by Tokyo in its effort to purge China of one of the more embarrassing, and threatening, reminders of Japan's brutal military occupation of parts of the country in the 1930s and '40s.
Beijing says the weapons have continued to injure and kill since the end of World War II, harming as many as 2,000 Chinese and damaging the environment. Eighteen alleged postwar victims are finally to get a hearing in a Tokyo court in February or March after years of filing suit for compensation.
Japan's agreement to clean up the arms also came after years of contention and negotiation hampered by Tokyo's long refusal to acknowledge formally that such munitions were used, despite the discovery of so many left behind.
Most of the weapons found so far were in the northeast, in what was the puppet state of Manchukuo under the Japanese imperial regime.
Sometime after the war, the Chinese military rounded up all the abandoned weapons it could find--some of the locations were contained in Japanese records--and selected a remote, mountainous area, Haerbaling in Jilin province, to serve as a repository.
"Because of financial and technical reasons, we weren't able to destroy them, so we collected them all together and buried them," said Ge Guangbiao, deputy director of the Chinese government agency overseeing the cleanup project. "This was the only thing we could do."
Shells, Canisters and Drums Fill Pits
In two large pits, Chinese soldiers interred a vast stockpile of munitions: 670,000 artillery and mortar shells, smoke canisters, huge drums of chemicals, perhaps some bombs.
Their payloads were designed to disable and, possibly, kill the enemy, and to control crowds. In addition to numerous vomiting agents, there was a potentially lethal "mustard gas" compound that inflamed and blistered victims' eyes, lungs and skin, and an agent that induced tearing and coughing and made breathing difficult--and that in high doses could also inflict death by suffocation.
The chemicals are not as deadly as the nerve agents found in other parts of the world--just a dab of those can be fatal within minutes--but they are nonetheless hazardous to both humans and the environment.
Few people live in Haerbaling, a forested area near the meandering Songhua River. During fine weather, says someone who has visited the site, it seems "an ideal place for a picnic" but for the fences and the occasional soldier guarding what is considered military property, off limits to civilians.