I was at work today, and this guy named harold who is pretty smart was discussing the safety of CO2 with his coworker. We fill CO2 tanks like those used for grilling (I think)..anyway, he said that unlike compressed air, you cannot get hurt by CO2 rushing out of a broken valve. He said that while air, if compressed enough, can lacerate/cut off a finger. However, he said that CO2 will not do that, no matter how compressed. One key word I heard was vapor pressure. Can someone explain this a little further?