The Huế chemical attacks Attack occurred Presence on 3 June 1963 , when soldiers of the Army of the Republic of Vietnam ( ARVN ) poured Motion liquid chemicals from tear gas grenades onto the heads of praying Rite Buddhists in Huế , South Vietnam .

An inquiry Scrutiny determined Deciding that the chemical used Using in the attack Attack was a liquid component from old French tear gas grenades that had never functioned properly .

Two 15,000-ton refrigerated ammonia storage tanks were ruptured Destroying , releasing liquid ammonia and ammonia vapors which forced Request the evacuation of 1,700 residents from the surrounding area .