QUANG TRI PROVINCE, Vietnam - Though the war in Vietnam ended nearly 40 years ago, dangerous relics of the conflict still remain. CBS News recently followed demolition experts from Project Renew as they searched -- and found -- leftover bombs.

America dropped three times as many bombs in Vietnam as it did in World War II. Some estimates suggest as many as 10 percent didn't explode -- and are still waiting to kill.

One of our guides, Duong Tam, showed us how dangerous it can be. During the search we came across a bomb that Tam said was armed.

"If anyone picks it up, it can set it off," Tam cautioned.

Chuck Searcy, founder of Project Renew. Left, Searcy in 2015. Right, Searcy during Vietnam. CBS News

Chuck Searcy founded Project Renew in 2001 shortly after he came back to Vietnam to still the anger of an idealistic young soldier in Saigon who had volunteered for the Army, specialized in military intelligence, and then turned against the war.

"I feel a responsibility to try to deal with the consequences of war that we left here, that the Vietnamese are still facing today," said Searcy.

The million dollars Searcy raises in grants and gifts helps Project Renew destroy 7,000 objects a year. No one knows how many more years, or decades, it will take to clean up Vietnam.

"I think Vietnam will never be ordinance free," said Searcy. "But what is realistic, what is an achievable goal, is making Vietnam safe."

Examples of bombs unearthed in Vietnam by Project Renew Project Renew

Before demolition, nearby residents are warned away. Even the cows are evacuated. And then -- as it may for years to come -- Vietnam's countryside echoes with the sound of a long-ago war.