skip to content

Facilities Management

Physical Plant • University of Maine at Fort Kent • 23 University Drive, Fort Kent, ME 04743

 Dry Ice: The Cold Facts

September 26, 2021
Posted by: Jason Guerrette

It’s the “smoke” drifting across a stage or the packet in a shipment of perishable food items. Dry ice is frozen carbon dioxide (CO2) and sublimes or goes from a solid to a gas without becoming a liquid. One pound of dry ice will sublime to produce 8.8 ft3 of CO2 gas. In a typical cooler, dry ice will sublime at a rate of 1-2%/hr. When left at room temperature it sublimes at a much faster rate. A 2 pound block of dry ice left at room temperature may sublime completely in as little as 15 minutes, and pellets even faster.

photo of a beaker on a scale with a chemical creating fog around the beaker

OSHA limits CO2 8 hr. exposure to 5000 ppm or 0.5%. Levels approaching 4% are dangerous. This means that as little as 5 pounds of dry ice left over the weekend in a walk-in cooler with no air circulation could potentially raise the CO2 to a hazardous level by the start of work on a Monday morning! If dry ice has been in a closed space, open doors and allow adequate ventilation before entering the space. CO2 is heavier than air and will accumulate in low spaces. Do not enter closed storage areas that have contained dry ice before airing out completely. Warning signs for CO2 exposure include rapid breathing, and blue lips or fingernails. Any of these mean it’s time to get to fresh air!

Do not store dry ice in airtight containers. The sublimation of dry ice to CO2 gas will cause an airtight container to expand or possibly explode.

Dry ice is extremely cold at -109.3°F. Contact with bare skin can cause frostbite. Always handle dry ice with care. Wear protective clothing, and insulated gloves whenever touching it, and use tongs if possible.

What Went Wrong?

One woman died and another was in critical condition after the car they were driving filled with CO2 when coolers in the back seat containing dry ice leaked.

Three people died in a swimming pool that dry ice was thrown into for theatrical effect. The CO2 quickly overcame those that were in the pool at the time.

Summary Tips

  • Store in ventilated area
  • Do not use in confined spaces or unventilated rooms
  • Do not store in sealed containers
  • Avoid contact with skin

Questions?

If you have any further questions or need assistance with safe handling of dry ice, please don’t hesitate to contact Safety Management at 581-4055 or email us at sem@maine.edu.