Dry ice, the solid form of carbon dioxide (\(\text{CO}_2\)), is a substance sought for its extreme cold and unique properties. With a surface temperature of approximately -109.3 degrees Fahrenheit (-78.5 degrees Celsius), it is significantly colder than regular water ice. Its primary function is sublimation, the process where it transitions directly from a solid state into a gas, bypassing the liquid phase entirely. This characteristic makes it highly effective for deep-freezing items, shipping perishable goods, or creating dense fog effects without leaving a wet residue. People often seek it out for emergency refrigeration during power outages or for specialized applications requiring sustained, ultra-low temperatures.
Common Retail Locations
The most accessible places for the general public to purchase dry ice are typically major retail chains and large general merchandise stores. Many national grocery store chains stock dry ice in blocks or pellets. This availability, however, is not universal across all branches and frequently depends on regional demand or seasonal needs. Customers should call ahead to confirm current stock and purchasing limits.
Large big-box stores and some hardware retailers may also carry dry ice, especially those that offer shipping services or cater to seasonal activities. At these consumer locations, dry ice is usually sold in smaller quantities, such as five-to-ten-pound blocks, suitable for temporary cooling needs. These retail suppliers generally offer the product in pre-packaged forms, sometimes wrapped in paper or placed in a bag to provide a minimal layer of insulation.
Pricing at these locations is typically per pound and is often slightly higher per unit than what is found at bulk industrial suppliers. Consumers should plan to purchase their dry ice as close to the time of use as possible, as even in an insulated container, it will sublimate at a rate of five to ten pounds every 24 hours.
Specialized and Bulk Suppliers
When larger volumes are required, specialized suppliers offer a more robust and consistent source of dry ice. Industrial gas companies are primary providers, offering the product in forms like blocks, pellets, or high-density “rice” for specialized cleaning applications. These companies often cater to commercial clients but will sell to the public, typically requiring a minimum purchase amount larger than retail quantities.
Dedicated ice supply companies, which may also deal in water ice, are another option. Certain medical or research supply distributors, who utilize dry ice for shipping biological samples, may also provide the product. Customers purchasing from these industrial sources may find better per-pound pricing for bulk orders, but they should be prepared to provide their own appropriate, insulated container for transport.
Safe Acquisition and Transportation
Acquiring and transporting dry ice requires careful adherence to specific safety protocols due to its extreme cold and gaseous nature. Direct contact with the solid material must be avoided, as its temperature of nearly -110 degrees Fahrenheit can cause severe frostbite within seconds; insulated gloves, oven mitts, or tongs must be used for all handling. The gas it releases, carbon dioxide, is heavier than air and can accumulate in low-lying, enclosed spaces, displacing oxygen and posing a risk of suffocation.
When transporting dry ice in a vehicle, ensure proper ventilation by opening windows or setting the air conditioning to draw in fresh air from outside. The product should be kept in the trunk or a separate compartment away from passengers, and the air conditioning system should never be set to recirculate cabin air.
Dry ice must be stored in an insulated container, such as a Styrofoam cooler, but the container must never be airtight. Sublimation causes the solid to release a large volume of \(\text{CO}_2\) gas, and if the container is sealed, the rapidly expanding gas will create pressure that could cause the vessel to rupture or explode. The container must be able to vent the gas safely, which is why a cooler with a loosely fitting lid or one with a dedicated vent is the only acceptable method for storage and transport. Following these guidelines ensures that the acquisition process remains safe for the individual and for others nearby.