Is Dry Ice Dangerous?

Dry ice is frozen carbon dioxide. Florida International University safety guidelines say it does not become a liquid but transforms directly into a gas, a process called sublimation, and that it sits at minus 109 degrees Fahrenheit. The CDC says dry ice looks like ice but is a cryogenic material that can cause severe frostbite if it touches skin for more than a few seconds.

Sealed containers can burst. The CDC says not to store dry ice in a tightly sealed container, because as it changes from a frozen state to a gas it may cause an airtight container to expand and potentially explode. Lawrence Berkeley National Laboratory safety staff say dry ice can, will and has on many occasions caused closed containers to explode, even ones where a lid was only loosely applied.

The gas builds up in closed spaces. Florida International University says that if dry ice is transported inside a car or van for more than 15 minutes there should be fresh air, since after 15 minutes without circulating fresh air people may start to feel symptoms such as faster breathing and headaches. The NIOSH Pocket Guide lists carbon dioxide exposure symptoms including headache, dizziness, restlessness, breathing difficulty, sweating, increased heart rate and blood pressure, coma, asphyxia and convulsions, along with frostbite from dry ice. It lists a recommended exposure limit of 5,000 ppm as a time-weighted average and 30,000 ppm as a short-term limit, and an OSHA permissible exposure limit of 5,000 ppm.