Originally Posted by emalvick

All I am saying is there is ventilation above the toilet seats, but not necessarily below them. I work in a broad environments where there are more than just port-a-potties (CO, Methane, Sulferous gases, etc), and they all are heavier than oxygen and can lower the amount of oxygen. The key thing is that if the oxygen concentration drops below the right level, it can cause problems.

It's just worth being cautious and not stick your head in below the toilet seat. I tend to ride in places where the toilets are vaulted toilets not port-a-potties, and I would not be able to reach things. I only encounter port-a-potties in races, so yes I probably could reach a phone in that environment, but most toilets I encounter I couldn't.

Anyway, enough of that. I only wanted to note that there is a legitimate risk of death, and as long as someone is aware of it, they will improve their chance of survival and could perhaps retrieve a lost item. It's better to be cautious than to assume it isn't going to kill you at all. Look up information about confined space deaths. They happen, mostly because people think it can't happen to them. It can, and it does.