Dry Ice Shipping Regulations: Limits, Labels, and Training

Dry ice shipping regulations classify solid carbon dioxide as a Class 9 hazardous material under United Nations identification number UN1845, and anyone shipping it must follow specific rules on packaging, quantity, marking, and documentation. The core requirements: the container must vent carbon dioxide gas, the outside must be marked with the shipping name and net weight of the dry ice, and packages over 2.5 kilograms trigger the full hazmat framework, including a Class 9 label, shipping papers, and trained personnel. Civil penalties reach $102,348 per violation, so the details are worth getting right the first time.

Why the Rules Exist

Dry ice sublimates directly from solid to carbon dioxide gas at room temperature. Two hazards follow. A sealed container can rupture from the pressure of the expanding gas, and escaping carbon dioxide can displace enough oxygen in a confined space — a truck compartment, a sorting facility, an aircraft cargo hold — to cause suffocation. Federal rules are built around preventing both.

How Dry Ice Is Classified

Under the Department of Transportation’s Hazardous Materials Regulations, dry ice carries the proper shipping name “Carbon dioxide, solid” and is assigned to Class 9 (Miscellaneous Dangerous Goods) with UN1845 as its identification number.¹ Class 9 covers materials that present a transportation hazard but don’t fit the flammable, corrosive, or other named classes. UN1845 is the universal identifier emergency responders and carriers use to recognize the material.

International air shipments also fall under the International Air Transport Association’s Dangerous Goods Regulations, which generally align with federal rules. Cross-border air shipments need to satisfy both.

Packaging Requirements

Venting is the rule everything else builds on. Every container used to ship dry ice by air or water must allow carbon dioxide gas to escape so pressure cannot rupture the package.¹ Airtight or hermetically sealed containers — glass jars, sealed metal cans, certain rigid plastics — are prohibited. Most shippers use expanded polystyrene foam coolers inside corrugated fiberboard boxes, a combination that insulates the contents while venting gas through seams and the foam itself.

The outer packaging must meet the general packaging standards in 49 CFR Part 173, Subpart B, but does not have to meet the performance-tested packaging specifications in Part 178.¹ Practically, the box needs to survive normal handling and hold together after the dry ice fully sublimates and leaves empty space inside.

How Much Dry Ice You Can Ship

Quantity limits depend on the mode of transport and, for air, whether the flight carries passengers.

The 2.5 kg Small-Quantity Exemption

Packages containing 2.5 kilograms (5.5 pounds) or less of dry ice used as a refrigerant are exempt from most hazardous materials requirements. No Class 9 label. No shipping papers. No hazmat training mandate for the person preparing the package.¹ To qualify, the package still has to vent, still has to be marked “Carbon dioxide, solid” or “Dry ice,” still has to name the contents being cooled, and still has to show the net weight of the dry ice (or indicate that it’s 2.5 kg or less). This exemption is why small food and meal-kit shippers can include dry ice without running the full hazmat compliance track.

Air Shipments Over 2.5 kg

Above 2.5 kg per package, the full framework applies: documentation, Class 9 label, trained personnel. The FAA limits passenger-aircraft shipments to 2.5 kg (5.5 pounds) per package.² Cargo-only flights allow up to 200 kg per package under IATA Packing Instruction 954. When dry ice is loaded as a refrigerant inside a unit load device (the large cargo containers airlines use), the standard Hazardous Materials Table quantity limits do not apply, but the shipper must inform the airline in writing of the total dry ice weight inside the device.¹

Ground Shipments

Federal rules in 49 CFR 173.217 focus on air and water. Ground shipments generally do not require a Shipper’s Declaration for Dangerous Goods, though the package still needs proper markings and the carrier still needs to know what it’s handling. Individual ground carriers may impose their own weight limits, so confirm before booking large loads.

Marking and Labeling the Package

Every dry ice package needs clear, durable markings on the outside:

“Dry ice” or “Carbon dioxide, solid” — the proper shipping name.³
The name of the contents being cooled, such as “frozen seafood,” “vaccine,” or “lab specimens.”
The net weight of the dry ice itself, written on the outside of the package. For air shipments, the weight must appear near the Class 9 label.¹

Weigh the dry ice by itself before loading the cooler. The marked figure is the dry ice only, not the packaging or product. Convert to kilograms for any air shipment; IATA requires metric. Five pounds becomes 2.27 kg on the label.

The Class 9 Label

Packages above the 2.5 kg exemption need a Class 9 diamond-shaped label: white background, seven black vertical stripes on the upper half, and the number “9” centered at the bottom.⁴ Place it where tape, strapping, or other labels won’t cover it. Packages that qualify for the small-quantity exemption do not need this label.

Shipping Papers and Handoff

Shipments over 2.5 kg need documentation traveling with the package. Federal rules give some flexibility: dry ice is exempt from the standard shipping paper requirements in 49 CFR Part 172, Subpart C, provided alternative written documentation lists the proper shipping name, Class 9, UN1845, the number of packages, and the net quantity in each.¹

Air shipments typically require an IATA Shipper’s Declaration for Dangerous Goods certifying that the cargo has been packed, labeled, and declared correctly.⁵ This applies to FedEx, UPS, and other private-carrier air service. For ground transport, a waybill or manifest notation identifying UN1845 and the weight is generally sufficient.

You cannot drop a dry ice package into an unattended collection box. Facilities that accept hazardous materials for air transport must display hazmat restriction notices, and unattended locations like drop boxes are covered by a prohibition on hazardous material deposits.⁶ Hand the package to an authorized agent.

One useful exemption: the 24-hour emergency response telephone number required for most hazmat shipping papers does not apply to shipments made under the proper shipping name “Dry ice.”⁷

USPS Has Its Own Rules

The Postal Service handles dry ice differently from private carriers in several ways. For air services like Priority Mail Express, USPS caps dry ice at 5 pounds per mailpiece, requires a Shipper’s Declaration (prepared in triplicate and affixed to the outside), and requires a Class 9 label.⁸⁹

Surface mail is more relaxed. Ground mailpieces can hold more than 5 pounds of dry ice, and neither a Shipper’s Declaration nor a Class 9 label is required. But the package must be marked “Surface Only” or “Surface Mail Only” alongside “Carbon Dioxide Solid, UN1845” or “Dry Ice, UN1845” on the address side.⁹ Missing the surface-only marking creates a real risk that the piece gets routed to an aircraft it wasn’t prepared for.

USPS also prohibits mailing dry ice to any international, APO, FPO, or DPO address.⁸ Overseas military destinations need a private carrier that accepts hazmat internationally.

Shipping Biological Specimens with Dry Ice

Medical labs and research facilities routinely ship diagnostic specimens, tissue samples, and vaccines packed in dry ice, which combines two rule sets. A Category B infectious substance (UN3373) packed in dry ice must use a triple-packaging system: a leak-proof primary receptacle, a leak-proof secondary container, and a rigid outer box.¹⁰

The dry ice goes outside the secondary packaging but inside the outer box. Interior supports must keep the secondary container in place even after the dry ice is gone, so specimens don’t shift and break during handling. For liquid specimens, absorbent material between the primary receptacle and secondary packaging must be sufficient to absorb the full contents if the primary container fails.

Employee Training

Anyone who packages, marks, labels, or prepares shipping papers for dry ice above the 2.5 kg exemption is a “hazmat employee” under federal law and must be trained. The training covers four areas: general awareness of hazmat regulations, function-specific training for the employee’s actual duties, safety training on emergency response and accident prevention, and security awareness training.¹¹

New employees can perform hazmat duties before finishing training, but only under direct supervision of someone already trained. Training must be completed within 90 days of hire or a change in job duties. Recurrent training is required at least every three years.¹¹

Employers must keep a training record for each hazmat employee: name, most recent completion date, description of training materials, name and address of the trainer, and certification that the employee was trained and tested. Records must be retained for the entire time the person works in a hazmat role and for 90 days after. This is where DOT inspectors most often find violations. The training happened; nobody documented it.

What Noncompliance Costs

A knowing violation of the federal hazardous materials transportation law carries a civil penalty of up to $102,348 per violation.¹² If the violation causes death, serious injury, or substantial property destruction, the maximum rises to $238,809. Each day a continuing violation persists counts as a separate offense. The only minimum penalty, $617, applies specifically to training violations.

Criminal exposure exists too. Willful or reckless violations of the hazardous materials transportation law can bring fines under Title 18 and up to five years in prison. If the violation causes a release that results in death or bodily injury, the maximum doubles to ten years.¹³ Beyond government penalties, carriers can permanently ban shippers who violate hazmat procedures, which for a business dependent on cold-chain logistics can hurt more than the fine.

1
eCFR. 49 CFR 173.217 – Carbon Dioxide, Solid (Dry Ice)
2
FAA. PackSafe – Dry Ice
3
U.S. Department of Transportation. Check the Box for Dry Ice
4
eCFR. 49 CFR 172.446 – CLASS 9 Label
5
IATA. Shipper’s Declaration for Dangerous Goods
6
eCFR. 49 CFR Part 175 – Carriage by Aircraft
7
eCFR. 49 CFR 172.604 – Emergency Response Telephone Number
8
United States Postal Service. Publication 52 – Hazardous, Restricted, and Perishable Mail
9
United States Postal Service. USPS Packaging Instruction 9A – Dry Ice (Carbon Dioxide Solid)
10
IATA. Packing Instruction 650
11
eCFR. 49 CFR 172.704 – Training Requirements
12
eCFR. 49 CFR 107.329 – Maximum Penalties
13
Office of the Law Revision Counsel. 49 USC 5124 – Criminal Penalty