Originally Posted by Byron Kinnaman
Dry ice (frozen CO2) is non-toxic. The melting dry ice will create pressure inside the ice box, which will vent around the door gasket. Door gaskets are NOT strong enough to hold the pressure back, therefore venting will happen without problems.
Since CO2 in NON-toxic it's not going to hurt you. The biggest concern would be replacing the O2 in the air, which takes a whole lot of CO2. Just to be safe when inside the trailer leave a window open a bit.
Bobbie, if you put a chunk of dry ice in a pop bottle and seal it will explode, no flame, just a bang. Look up explode.
Dry Ice (or rather the resulting gaseous CO2) is not non-toxic. The risk has nothing to do with pressure building up. Dry Ice sublimes, as I am sure you know, into gaseous carbon dioxide. CO2 is heavier than nitrogen or oxygen
, and settles into the trailer. I calculated the amount of gas produced by a pound of CO2. The short-term exposure limit is 1.5%. It doesn't simply suffocate though it can do that, too.
One pound of CO2 would give greater than a 2% concentration in a 13 foot trailer (assuming it was completely empty, dimensions 10x6x6 feet.) More Dry Ice or more stuff in the trailer raises the concentration. 1.5% = 15,000 ppm (OSHA limti is actually only 5000.)
Ventilating has limited effect due to the tendency of CO2 to sink to the floor (leaving the door open would help more but who does that all night?)
Toxicity info: http://www.continentalcarbonic.com/pdf/MSDS_Dry_Ice.pdf