Mystery Gas Engulfs Danang, Vietnam Residents

HANOI (Reuters) - Local authorities in central Vietnam said on Monday they were probing an incident in which thousands of local residents had been affected by a mystery cloud, believed to be teargas.

An official with the Danang People's Committee told Reuters hundreds of families were evacuated from the city's central Thanh Khe district last week suffering symptoms including nausea, eye irritation and breathing problems.

Residents in the area, who have since been allowed to return to their homes, told Reuters they began having difficulty breathing around midnight on January 11.

``I thought it was teargas so we put wet towels on our faces to protect ourselves,'' a woman said by phone. ``The police arrived later wearing gas masks and protective suits and began dousing streets.''

The district official said police had arrested -- and were questioning -- two people to determine where the gas had come from.

``We think it was CS-Two gas,'' he said. ``We're assuming it was left from the war.''

CS-Two is a compound used in teargas, which is often used for riot control.

Local newspapers said on Monday that one of the two men they were questioning had been arrested while emptying a chemical tank into the city drains. Several kilos were reported to have been spilled.

While it was not clear whether the chemical was residual from the Vietnam war, which ended in 1975, military equipment, unexploded ordnance and other remnants of the conflict remain strewn across large areas of Vietnam.

Danang was the second most important city in U.S.-backed South Vietnam, and was used as a major supply and military base. It was also the site of protests last year by residents over a land dispute.