Two rusty barrels discovered in Mondulkiri province this week have been identified as 1970s-era chemical bombs, officials said yesterday.

Heng Ratana, director general of the Cambodian Mine Action Centre (CMAC), said that a team of experts had inspected the barrels, which were found near O’Raing district’s Andoung Kraloeng village, and could “now confirm, based on the inspection, they are bombs containing CS, or tear gas”.

Ratana said that there was “no sufficient evidence to confirm which country they were used by” but said they dated from around 1969 to the early 1970s.

CS was one of a number of chemicals known to have been used by the US during its war with Vietnam.

Chey Son, a secretary at the National Defense Authority of Chemical Weapons, said the barrels “hold chemicals from the US’s war with the region”.

“We have banned people from the [surrounding] area, and we and CMAC are waiting for technical [support] and sponsorship from another country. And we are working with US [for this]. If we get this, we can clean it,” he said.

According to CMAC’s Ratana, known effects of CS include itching and respiratory problems.

When similar weapons were found in 2010 and 2012, he said, people in the surrounding areas reported that the toxins were making them unwell.

“We need to work out procedures to remove the barrels as soon as possible to ensure safety,” he said.

Villager Bil Vanty said that he and others living in the area had experienced health problems. “We wondered why we were itching and getting headaches when we walked near the pond where we found the barrel. After that, we were too scared to walk there.”