In the laboratory, dry ice is commonly used to cool chemical reactions and keep biological shipments cold. With Halloween right around the corner, we can’t forget that dry ice is also used as part of Halloween decorations and displays. Whether you’re using it in the lab, or for Halloween, there are some important safety considerations to keep in mind.
Dry ice is the solid form of carbon dioxide (CO2). It comes as flakes, pellets, or block forms. Dry ice is extremely cold (-109 °F or -79 °C), and unlike ice made from water, dry ice does not melt. Instead, it rapidly changes from a solid to carbon dioxide gas at temperatures above -109°F in a process called sublimation.
Carbon dioxide gas is heavier than air and because of that it can displace oxygen, causing difficulty breathing or even asphyxiation. Dry ice should only be handled and stored in a well-ventilated area. It should never be used or stored in areas that have unventilated or re-circulating atmospheres, such as warm rooms and cold rooms.
Some additional safety recommendations to keep in mind are:
Handling
Avoid contact with skin and eyes! Because dry ice is extremely cold it can cause severe cold burns and frostbite within seconds of direct contact. Never handle dry ice with your bare hands; always wear insulated gloves or use tongs. To protect your eyes and face, safety glasses, goggles, or a face shield should also be worn.
When scooping or collecting dry ice, do not submerge your head into the container. If you develop a headache or are having difficulty breathing, leave the area immediately.
Do not put dry ice in your mouth or otherwise ingest it. If ingested, seek medical attention immediately. If dry ice is accidentally ingested, it can cause severe internal injury. Never put dry ice in beverages to cool them.
It’s also important to remember that dry ice should only be handled by adults. Keep out of the reach of children!
Storage
As mentioned above, dry ice should aways be stored in a well-ventilated area to minimize the buildup of carbon dioxide. Never store dry ice in tightly sealed or airtight containers. If the carbon dioxide gas has nowhere to go due to dry ice releasing the gas so rapidly, it can pressurize the container which could cause it to explode with the possibility of serious injury. Dry Ice should be stored in in a Styrofoam container, insulated cooler, or a special cooler designed for dry ice storage. Do not store it in laboratory or household refrigerators or freezers!
Transport
If dry ice has to be transported in a personal vehicle, it should be transported in a trunk that is completely separate from the main cabin of the car, or in a truck bed.
The package must be secured against movement and protected from damage. Note that the DOT Materials of Trade regulations apply for workplace transportation of dry ice using a personal vehicle.
Disposal
Dry ice should not be disposed of in places such as sinks or toilets as it can damage pipes and other plumbing. To dispose of dry ice, leave the dry ice in an appropriate container (e.g., Styrofoam) with the lid partially on the package in a well-ventilated room; this allows for sublimation. When possible in a lab setting, the package should be placed adjacent to a chemical fume hood until the dry ice is gone. After the dry ice is completely sublimated, the container can be discarded.
For additional information on dry ice safety, please email us at [email protected]. Have a happy and safe Halloween.