Police and federal workplace safety officials are investigating an industrial accident that killed a Naugatuck man at Sikorsky Memorial Airport in Stratford shortly after 8 a.m. Thursday. According to officials, 57-year-old Antonio Simoes, a worker for Manafort Construction, was in a trench using a gasoline-powered saw to cut a water main when the saw kicked back and caused a fatal cut to the his neck. Simoes was pronounced dead at the scene. Manafort says he had worked for the company since 1996.