Originally Posted by
cyccommute
I know that there's no oxygen down there. Still, you should be able to hold your breath for a couple of minutes and it takes a couple more for you to suffocate so that's 3 to 4 minutes total to root around for your phone. You'd think they would come up for air before it got that critical.
And it's not like you would have to go in head first to try and find it. It would be bad enough to stick your arm in there without having to go for the whole body experience!
I work alongside OSHA on similar situations: construction workers losing items in toilets, inadequately ventilated manholes, vaults, etc. It isn't that you can't hold your breath, it's that you are breathing in carbon-monoxide and sulfurous gases that will kill you before you know it. I'm not saying it's a guarantee you'll die, but most people who die didn't think it was going to happen to them.
Of course you might be able to do it with your arm, but my feeling is that most of the times those things are too deep to just reach down into.