I lost a school buddy that way as well--he was on a hunting trip and
sleeping in his truck (with cap). Never woke up--18 years old.

Randy Moe wrote:
> In 1971 at a Midwest mud buggy event we woke up with a dead man in the
> van next to us. He was using an unventilated catalytic  heater. His
> son and the dog survived. I threw mine out that day.