When carbon dioxide is in its solid form it is known as dry ice, and primarily is used in commercial refrigeration applications where conventional methods of cooling are not possible, such as in the transportation of perishable goods, or in scientific or industrial applications. It is an advantageous method of cooling in comparison to regular (water) ice as it reaches significantly lower temperatures when in its solid state, and leaves no residue (as regular ice would produce water) because it undergoes sublimation – the chemical process of a solid transforming to a gas without first becoming a liquid.
Because dry ice can reach such low temperatures, it becomes very dangerous to handle without proper protection. If touched directly for more than a very brief moment, dry ice can cause cellular damage (frostbite) similar to that of a burn, and if significant enough, should be medically treated in the same fashion. Also, because it sublimates into such large amounts of carbon dioxide gas, there is a risk of accumulating too much of the gas in the blood. For this reason dry ice packs should only be handled in open, ventilated areas. Protective leather gloves are often worn to create a barrier between the ice and skin. Alternatively, a thick cloth may be used. Long pants and close-toed shoes are needed to protect your lower extremities in the event the ice is dropped. Transportation of it requires a semi-open container to allow for any buildup of gas to escape. Tongs are ideal instruments to use to pick up blocks of dry ice, and pieces of it can be broken off with a chisel and mallet. Excess material can be disposed of simply by pouring warm water over it.
Other handling considerations include using solid surfaces such as a wooden cutting block for placement, as dry ice can destroy the adhering agent in tile or laminated materials. When transporting it in a vehicle, roll down the windows if placed in the interior of a car or truck. Placing dry ice in direct contact with perishable foods may cause burns to the items. Lastly, never ingest dry ice as is sometimes done with mixed drinks, as it can harm the esophagus