DONG HA, Vietnam (AP) -- Nguyen Xuan Thiet knew the copper band around the base of the American bomb left over from the Vietnam War could fetch him up to a dollar at the scrap yard. So he clasped the projectile between his bare feet, and began banging with a chisel to pry out the precious metal.
It was nearly the final act of his life. The bomb exploded, tearing both legs off below the knees and four fingers. Only the quick work of a friend -- who lashed tourniquets around his limbs, hurled him on the back of a motorbike and sped to a hospital -- saved his life.
On Aug. 15, 1973, the United States flew its final bombing mission over Southeast Asia, ending the country's direct military involvement in the war. Forty years later, victims are still falling in one of the grimmest legacies of the conflict. Last year alone, there were at least 500 casualties in Vietnam, Laos and Cambodia from unexploded bombs and other ordnance, according to activists and government databases.
The most heavily contaminated province in Vietnam is Quang Tri, where fighting between U.S. and Vietnamese forces was at its fiercest. The region is now one of the poorest in the country. The prices of steel and copper are continually rising, maintaining incentives for collectors even as much of the lightly buried scrap has already been harvested.
"Unexploded ordnance is a resource; we have to exploit it," said Thiet who after the accident in late 2011 had prosthetic limbs fitted courtesy of an American charity funded mostly by the U.S government. "If I hadn't lost my legs, I would still go out to collect scrap metal."
Collecting scrap is not illegal in Vietnam, but handling unexploded ordnance is. Many collectors say they now leave dangerous items in the field and concentrate on the tons of other war remnants like exploded bomb casing, machinery and vehicles. Scrap metal dealers also say they refuse live munitions.
Yet it is clear there are people prepared to defuse unexploded bombs to harvest and sell their casings as well as their explosives, which are used in the fishing and mining industry. Neatly sawn projectiles and other bomb parts are easy to find in roadside scrap yards.
"There are people who do that, but they keep it quiet," said Nguyen Van Binh, a scrapyard owner who recently paid $4,000 for a large haul of war scrap from across the border in Laos, including 500-pound bomb casings and mounds of bomb fragments.
Most collectors are aware of the dangers, none more so than Nguyen Thi Tam. Her husband was killed dismantling a bomb 21 years ago, leaving her to bring up four children alone. Desperately poor, the 48-year-old has little choice but to continue with his trade.
One recent morning saw her shoulder a cheap metal detector and a hoe and cycle to a former battlefield dotted with grave stones of local villagers and clumps of wild pineapple. She passed the detector quickly over the sandy soil until her headphones began to squeal.
Without pausing, she hacked away the grass with the hoe, and then used a bare foot to swish away the dirt to reveal a projectile and the fuse of a rocket-propelled grenade. She left those where they were, and carried on working, pocketing several bomb fragments to take to the dealer.
"A bowl of blood for a bowl of rice," she said, explaining the tradeoff she is willing to make for what earns her $5 on a good day. "I know very well it is dangerous, but I must go on."
The United States dropped 7.8 million tons of munitions over Vietnam as it tried to bomb the impoverished nation into submission, more than it unleashed in World War II on Germany and Japan combined. It also fired off as much ordnance again from land and sea. An estimated 800,000 tons failed to detonate, contaminating around 20 percent of its land.
More than 100,000 people have killed or injured since 1975, the government says. But it doesn't give out detailed information publicly and many casualties go unrecorded. Curious children picking up small cluster munitions make up a significant percentage of those killed or injured.
"In summer time, the kids come out in groups to play," said Chi Hong Tran from Clear Path International, a mostly US-government funded charity that pays for medical and other expenses of those who fall victim. "When a bomb goes off, it takes everyone with them."