BAC GIANG - At first, Dinh Thi Bac thought the blast came from a blown tyre as someone drove past her scrap metal shop.
She looked outside and saw the air thick with smoke, and when it cleared a little she saw all the blood.
One woman lay badly hurt, bleeding and riddled with metal pellets in a corner.
Another ran, wounded, towards the road and collapsed where motorcycles are now parked a few metres away, Bac recalls.
"I was told that she died just a few hundred metres from here, on the way to hospital," Bac said.
More than 35 years after American warplanes dropped their last bombs on this area of northern Vietnam, they have killed again.
Nguyen Thi Van, 39, died and her co-worker, Nguyen Thi Lien, 33, was badly wounded when a cluster bomblet which they unknowingly collected exploded, local officials said.
The bomblet was among beer cans and other scrap metal the collectors wanted to sell and were weighing on a small green scale outside the village junk shop run by Bac, 26, and her husband Pham Van Trung, the officials said.
This was the first time in 30 years that anyone had been killed by unexploded ordnance (UXO) in this area, commune police chief Tran Xuan Dan said.
In comparison, Quang Tri province and other parts of central Vietnam have a much bigger UXO problem.
Quang Tri recorded more than 2,600 fatalities from bombs and other ordnance between the end of the Vietnam War in 1975 and December last year, according to Project Renew, which has spent years trying to protect Quang Tri residents from UXOs.
But Van's death in northern Bac Giang province, about 60 kilometres (37 miles) from Hanoi, emphasises the extent of the problem which all of Vietnam faces.
"I don't think there's any province in the country that is not affected to some extent by UXO contamination," says Chuck Searcy, country representative for the Vietnam Veterans Memorial Fund, which sponsors Project Renew.
Cluster bombs explode in mid-air to randomly scatter hundreds of small bomblets, many of which fail to explode and can lie dormant for decades until someone disturbs them.
The bomblet that killed Van was filled with metal pellets that penetrated her brain, said Nguyen Nhu Thang, chairman of the local commune's People's Committee.
Many other pellets tore into her co-worker Lien's legs. Some hit her in the face. She declined to comment when AFP found her sitting on her bed eating lunch at a district military hospital.
Dinh Thi Ha, 28, was luckier.
"I didn't know that I was hit. I was calling people to bring the victims to hospital when I saw that I was bleeding, and then suddenly the baby just cried," she said at her tailor shop beside the scrap metal business run by her sister and brother-in-law.
A pellet hit Ha in the leg and then went into her baby, Le Quynh Anh, who is just a few months old.
"The doctor had some difficulty getting the pellet out," Anh's mother said, showing two pea-sized marks that look like bruises on either side of the child's lower back.
Other than those marks, baby Anh, wearing a cute yellow hat, appears happy and physically normal.
"She is a bit sensitive to big sounds now," her grandmother Ninh Thi Hien, 51, said after the family shows off the pellet which they keep in a child's plastic purse.
The tile roof in front of the shops has been repaired but still carries about 10 pea-sized holes from the pellets that shot through it.
Ha said she never imagined that, three decades after the war, she and her baby would be hurt in this way.
Searcy called them victims of a weapon with almost no legitimate military application.
"For a baby to be injured by this, that's unspeakable. That's an unspeakable crime against humanity," he said at his Hanoi office.
But it was probably only a matter of time before someone got hurt in this commune of red soil and rice paddies, where more than 9,000 people live.
"There are still quite a lot of cluster bombs in this area," Thang said, adding that the women who delivered the scrap had no idea of the danger it posed.
Area residents report bomb discoveries several times a year, officials said.
Large bombs will be dealt with by higher-level authorities but the commune itself can take care of cluster bomblets by burying them with two kilograms (4.4 pounds) of salt in a hole, Thang said.
"After one month, it will be OK," Thang said.
Searcy, who served in army intelligence, reacted with shock when told of the commune's solution.
"Salt will not corrode," he said, adding local authorities put themselves at risk by moving the bomblets.
The incident in Bac Giang reinforces the need for a nationwide awareness campaign about bomb safety, Searcy said.
As part of its work in Quang Tri, Project Renew conducts a comprehensive education programme that uses everything from billboards, posters, radio and television to art contests and cultural events.
There is a free hotline, and people are taught to report things that look dangerous, Searcy said.
"It's now becoming institutionalised. It's a community practice so the whole community is sort of involved in the effort, but that doesn't exist in a place like Bac Giang province. Net yet anyway."
While northern Vietnam was bombed only from the air, Quang Tri and other areas of then South Vietnam were hit by everything from airborne bombs to artillery and sea-based weapons, accounting for the higher concentration of UXOs there.
Bac Giang would not need a public education programme as extensive as Quang Tri's, but some public awareness along with training for local officials might help keep people out of danger, Searcy said.
"One of the things that I hope can be implemented in Vietnam very soon, maybe this year, would be a national awareness programme about safety, even in areas such as Bac Giang where there are very few" incidents, he said.
Searcy is optimistic because of the Oslo Convention on Cluster Munitions which prohibits their use, production, transfer and stockpiling. The treaty entitles signatories to financial and other assistance for destroying the bombs and making local residents aware of their danger.
"We hold that the anti-cluster bomb treaty needs widespread participation," Foreign Ministry spokesman Le Dung said. "At present, Vietnam is considering participation in this treaty."
Countries began signing the Convention in December and Searcy said he expects Vietnam will soon adopt it, a move that could make "substantial resources" available against UXOs for the first time since the war.
He is hopeful that, in the future, fewer innocent people like Van will die because of left-over bombs.
"I think that we're entering into a period where Vietnam may be able to look at a decade of tremendous progress in cleaning it up."