High Explosive (movie, 1943)

Mike Douglas (Barry Sullivan), owner of a nitroglycerin concern hires his old friend "Buzz" Mitchell (Chester Morris), a race-driver of midget-auto cars who has been banned from racing, to go to work hauling nitro. "Buzz" makes a play for Connie Baker (Jean Parker), Mike's secretary and girlfriend, and also for Doris Lynch (Barbara Lynn), fiancée of Connie's younger brother, Jimmy ('Rand Brooks'), and gets Jimmy to replace him on a dangerous nitro haul and Jimmy, of course, has an accident and gets killed. But "Buzz" finds a way to redeem himself. The hard way.