Dry ice is the solid form of carbon dioxide, existing at an extremely cold temperature of approximately -109.3°F (-78.5°C). This substance does not melt into a liquid but instead turns directly into a gas, a process known as sublimation. This unique property makes it a powerful cooling agent that leaves no liquid residue, making it ideal for shipping frozen goods or creating special effects.
Locating Retail and Specialty Suppliers
The search for dry ice typically begins with general retail locations, which offer the product in smaller, consumer-friendly quantities. Many major grocery chains and large retail stores often stock dry ice in their freezer sections, especially for seasonal uses or emergency refrigeration. It is always advisable to call a store ahead of time to confirm their current supply, as inventory can be limited.
Specialty suppliers are the better option for those needing larger volumes or specialized forms of dry ice, such as pellets or blocks. These businesses include industrial gas distributors and welding supply companies. These suppliers are more likely to have bulk quantities available and can provide fresh product. They are also equipped to handle custom orders and often provide detailed safety instructions.
Essential Safety and Handling Procedures
Handling dry ice presents two primary physical hazards: an extreme thermal hazard and a respiratory hazard. The temperature is cold enough to cause severe frostbite or “cold burns” on contact with bare skin. Use thick, insulated gloves, such as leather or neoprene, or use tongs to move the material.
The second major risk is asphyxiation, which occurs as the dry ice sublimates into carbon dioxide gas. Since carbon dioxide is heavier than air, it tends to sink and accumulate in low-lying, unventilated areas like basements or car cabins. Dry ice must only be used and stored in locations with adequate ventilation to allow the gas to safely dissipate.
Proper Storage and Transportation
The proper storage of dry ice is designed to slow the natural sublimation process while preventing a pressure explosion. It should be kept in an insulated container, such as a styrofoam cooler, to minimize heat transfer from the environment. However, this container must never be airtight, as the continuous conversion of solid CO2 to gas generates significant pressure. A single pound of dry ice produces about 250 liters of carbon dioxide gas, which can cause a sealed container to burst.
When transporting dry ice in a vehicle, a cooler that allows for venting should be placed in the trunk or a cargo area separate from the passengers. If the material must be transported inside the main cab, it is crucial to maintain fresh air circulation by keeping the windows open or ensuring the ventilation system is drawing in outside air. Depending on the insulation and ambient temperature, dry ice typically sublimates at a rate of 5 to 10% every 24 hours.
Safe Disposal Methods
The only safe way to dispose of dry ice is to allow it to fully sublimate into the atmosphere. This process should be carried out in a well-ventilated area, preferably outdoors, where the carbon dioxide gas can disperse safely. If outdoor disposal is not possible, an open garage or a room with open windows and doors can work.
Never dispose of dry ice by placing it down a sink, toilet, or drain. The extreme cold can damage plumbing components, and rapid gas expansion in a sealed pipe can lead to blockages. The material should also not be thrown into the trash, as sublimation could cause a sealed garbage can to build up dangerous pressure.