Is Dry Ice Considered a Hazardous Material? Safety and Shipping Rules
Yes. In the United States, dry ice is generally classified as a hazardous material when it is transported commercially because it can release carbon dioxide gas as it warms. It is identified as UN 1845, Carbon dioxide, solid, and belongs to Hazard Class 9. That classification does not mean dry ice is always prohibited: it can be shipped when applicable packaging, marking, ventilation, and carrier requirements are followed. For everyday users, the main risks are pressure buildup, cold burns, and dangerous carbon dioxide concentrations in poorly ventilated spaces.
Why Dry Ice Is Considered a Hazardous Material
Dry ice is the solid form of carbon dioxide (CO2). At normal atmospheric pressure, it does not melt into a liquid. Instead, it sublimates, changing directly from a solid into gas. As a result, dry ice in a package continually produces carbon dioxide that needs a safe way to escape.
That gas creates two central hazards. First, if it cannot escape, pressure can build inside a sealed container and cause it to rupture or burst. Second, carbon dioxide can displace oxygen in the air. In a small, enclosed area, enough carbon dioxide can cause headache, dizziness, breathing difficulty, loss of consciousness, or death.
Dry ice is also extremely cold: its temperature is about −109.3°F (−78.5°C). Direct contact can injure skin in a way similar to a cold burn or frostbite. These properties explain why transportation rules treat it as a regulated material, even though it is commonly used to keep food, samples, and other products cold.
How U.S. Regulations Classify Dry Ice
The U.S. Department of Transportation (DOT) regulates hazardous materials transported in commerce under the Hazardous Materials Regulations (HMR), found in Title 49 of the Code of Federal Regulations. Under these rules, dry ice is listed as UN 1845, Carbon dioxide, solid, with a Hazard Class 9 designation. Class 9 covers miscellaneous hazardous materials that present a transportation hazard but do not fit the other main hazard classes.
The specific U.S. packaging provision for dry ice is 49 CFR § 173.217. The rules recognize that dry ice needs packaging capable of releasing gas, rather than a hermetic seal that traps sublimating carbon dioxide. Additional requirements depend on how and where it is shipped. Air transportation may involve stricter or more detailed requirements than a ground shipment, and carriers can impose their own conditions.
The legal distinction matters: a person using dry ice at home is not automatically subject to every commercial shipping requirement. However, the risks remain, and anyone offering dry ice for transport—or arranging a shipment that contains it—should check the rules for the specific transportation mode and carrier.
Shipping Dry Ice: What to Know
Dry ice can be shipped in the United States, but it must be prepared for the conditions of transport. A package needs to let carbon dioxide escape while protecting its contents and remaining strong enough for handling. Never put dry ice in an airtight container, such as a tightly sealed jar, bottle, or cooler that cannot vent. Pressure may rise as the dry ice sublimates.
Transportation rules and carrier instructions can require details such as the proper shipping name, identification number, hazard label, net weight of dry ice, and shipper or recipient information. Air shipments commonly require specific package markings and a Class 9 hazard label. The amount of dry ice allowed can also vary by aircraft type, shipment, and carrier policy. Requirements may differ for dry ice used as a refrigerant versus dry ice shipped as the product itself.
For a shipment, the shipper should confirm the current requirements with the carrier before packing. The carrier can explain whether the package needs a dry-ice declaration, a specific label, or advance approval. A shipment that meets a general packaging rule may still be rejected if it does not meet the carrier’s operational requirements.
Common Shipping Checks
- Use packaging that can vent: Gas must be able to escape without allowing the contents to spill or become damaged.
- Check the mode of transport: Ground, air, and international shipments can have different rules.
- Verify labels and markings: Confirm the proper name, UN number, dry-ice net mass, and any required hazard label with the carrier.
- Follow quantity limits: Limits may depend on the route, aircraft, package, and carrier.
- Check for other hazardous contents: Dry ice combined with biological samples, chemicals, or other regulated goods may trigger additional requirements.
Dry ice packed with food or a nonhazardous product does not necessarily make the contents hazardous, but the dry ice itself remains relevant to transportation rules. If the package also contains another regulated substance, the shipper must consider the requirements for both materials.
Dry Ice in Air Travel and Checked Baggage
Passengers may be able to carry dry ice on an aircraft, but the allowance is limited and subject to airline rules and applicable federal requirements. The Federal Aviation Administration (FAA) generally permits up to 5.5 pounds (2.5 kilograms) per person in carry-on or checked baggage when it is used to pack perishables and the baggage is vented. Airline approval is required, and the package must be marked to show it contains dry ice and state the net weight or indicate that it contains 5.5 pounds or less.
Because airlines can set additional conditions, travelers should contact the airline before arriving at the airport. The package must not be airtight, and dry ice should not be packed in a way that prevents carbon dioxide from escaping. Rules for cargo shipments are different from passenger-baggage allowances, so the 5.5-pound limit should not be treated as a general shipping limit.
Dry ice is not the same as an ordinary frozen gel pack for security purposes or baggage handling. Travelers should check current FAA and airline guidance, particularly when carrying dry ice with medication, laboratory specimens, or other items that may have separate restrictions.
Safe Handling and Storage at Home or Work
Safe handling starts with limiting exposure. Use insulated gloves or tongs to pick up dry ice; ordinary thin gloves may not provide enough protection. Keep it away from bare skin, eyes, children, and pets. If it contacts skin, do not rub the area. Seek medical advice for a serious injury or persistent pain, numbness, or skin changes.
Store dry ice in a well-ventilated location and in an insulated container designed to allow gas to escape. Do not store it in a sealed freezer, closet, basement, or other confined space. Do not put it in a beverage or allow anyone to swallow it. In vehicles, keep windows open or ensure there is adequate ventilation, especially when transporting a large quantity or driving for an extended period.
Carbon dioxide is colorless and odorless, so a person may not recognize a dangerous concentration by sight or smell. If someone feels dizzy, confused, short of breath, or unusually tired near dry ice, they should move to fresh air immediately and call emergency services if symptoms are severe. Do not enter a potentially oxygen-deficient area to rescue someone without appropriate training and equipment.
Dry Ice Hazards at a Glance
| Hazard | What Can Happen | Basic Precaution |
|---|---|---|
| Pressure buildup | A sealed package or container can rupture as dry ice produces gas. | Use packaging that allows gas to vent; never seal dry ice in an airtight container. |
| Carbon dioxide exposure | CO2 can displace oxygen and cause serious illness or death in a confined space. | Use and store dry ice in a well-ventilated area. |
| Cold contact | Direct contact can cause cold burns or frostbite. | Use insulated gloves or tongs and avoid touching it with bare skin. |
| Transport noncompliance | A carrier may refuse a package or a shipment may violate applicable rules. | Confirm current DOT, FAA, and carrier requirements before shipping or flying. |
Is Dry Ice Hazardous Waste?
Hazardous material and hazardous waste are different classifications. “Hazardous material” generally refers to transport regulation, while “hazardous waste” is a separate regulatory category concerning discarded materials. Dry ice is not automatically hazardous waste simply because it is regulated for transportation. Disposal practices should still prevent injury and allow the material to dissipate safely.
Small amounts can generally be left to sublimate in a secure, well-ventilated area away from people and animals. Dry ice should not be put in a sink, toilet, trash compactor, or sealed garbage container. Local rules or workplace procedures may require a particular method for larger quantities.
Reliable Sources for Current Requirements
Rules can change, and requirements depend on the shipment. For the governing U.S. transportation provisions, consult the Electronic Code of Federal Regulations, 49 CFR § 173.217. For passenger aircraft guidance, review the FAA PackSafe dry ice page and confirm the airline’s policy. The Occupational Safety and Health Administration (OSHA) carbon dioxide information is a useful workplace reference for exposure hazards.
In practical terms, dry ice is a hazardous material for transportation purposes, but it can be shipped or carried when the applicable rules are met. For everyday safety, the essential precautions are to prevent pressure buildup, provide ventilation, and avoid direct contact.