The alarm(s!) were going off for 14 hours! They were reset at least 4 times. How did no one think, "Oh, there might be a CO leak! I better investigate"?

The only correct thing to do when you hear a CO alarm is to evacuate and get someone with the tools to deal with the problem to help (usually the fire department).

Poor guy. I hope the other victims recover.

The person who turned the alarm off needs to be held accountable

There's stupid, and then there's *criminally stupid. I hope they throw the book at whoever was responsible...