100,000 parts per million is 10%. 500,000 ppm is 50%
So loss of consciousness with 30% within a minute, at 10% would cause loss of consciousness in 5 – 10 minutes. Death has happened with concentration as low as 11%. All this is based on the information in Sober's post. Looks like my crew would have all died in r/l with 35%, and they were still kicking!
Tough guys, these Germans.