Sounds like the five probably died quickly. I remember a dash-cam video from 2000 that showed an LEO driver getting out of his car and walking into a cloud of anhydrous ammonia to check on victims at a vehicle accident scene. He obviously didn’t identify what was leaking into the air from the small trailer. His radio mic was on and he just walked into the cloud, coughed, and keeled over. He didn’t breathe much longer.
Immediate death...................
Actually death from ammonia is very brutal. The ammonia combines with fluid in the lungs making ammonium hydroxide which is very basic with a high PH. It is like breathing fire and it is brutal. Happened to me as a kid and it was a leaking anhydrous ammonia tank. I was in a car and we drove through it quickly. If we had of been on foot it would have killed us.