Please remember these safety precautions when using dry ice.
Dry ice temperature is extremely cold at –109.3°F or –78.5°C. Never let dry ice touch your bare skin! Always handle with protective gloves, oven mitt, or towel.
Store dry ice in an insulated container. The thicker the insulation, the slower it will sublimate. Do not store dry ice in a completely airtight container. The sublimation of dry ice to carbon dioxide gas will cause any airtight container to expand or possibly explode. Keep proper air ventilation wherever dry ice is stored. Do not store dry ice in unventilated rooms, cellars, autos, or boat holds. The sublimated carbon dioxide gas will sink to low areas and replace oxygenated air. This could cause suffocation if breathed exclusively. Do not store dry ice in a refrigerator freezer. The extremely cold temperature will cause your thermostat to turn off the freezer.
How to Transport and Store Dry Ice Until Ready to Use
The best container to transport and store dry ice is an ice chest. It will still sublimate five to ten pounds each 24 hours, so plan to pick up the dry ice as close as possible to the time it will be used. Dry ice is very cold so use insulated gloves to handle it.
When finished with the dry ice, unwrap and leave it at room temperature in a well ventilated area. It will sublimate from a solid to a gas. Do not leave dry ice unattended around children.
How to Pack Dry Ice
If the dry ice is placed on top of the food (cold sinks), it will work better. However it is sometimes in the way so many people prefer to keep the dry ice on the bottom of the ice chest for convenience. When packing items in the container fill the empty space with wadded newspaper or other filler. Any "dead air space" will cause the dry ice to sublimate faster. The best storage container is a three-inch thick urethane insulated box. Lining the inside of your ice chest with sheets of Styrofoam will increase the life of dry ice. Dry ice sublimation (changing from a solid to a gas) will vary depending on the temperature, air pressure, and thickness of insulation. The more dry ice you have stored in the container, the longer it will last.
Transporting by Vehicle
Plan to pick up the dry ice as close to the time it is needed as possible. If possible pack insulating items such as sleeping bags around the ice chest. This will stretch the time that the dry ice lasts. If it is transported inside a car or van (not in the trunk) for more than 10 minutes make sure there is fresh air.
Transporting by Airplane
Pick up dry ice as close to departure time as convenient. Carry it in a well-insulated container such as an ice chest or insulated soft pack. If it is transported inside a car or van for more than 10 minutes make sure there is fresh air available. Most airlines will not let you carry more than two kilograms (4.4 pounds) of dry ice on the airplane without special arrangements. Because dry ice will sublimate continuously from the time of purchase, you can confidently declare that there is no more than two kilograms at the time you check in at the airport. Dry ice will sublimate slightly faster due to the lower pressure that the airline maintains during flight. Make plans to refrigerate or add dry ice when arriving at your destination.