Shipping with dry ice: the rules, the packout, and the record

Solid carbon dioxide, and why it is dangerous goods

Dry ice does not melt. At normal atmospheric pressure it turns straight from solid to gas, a process called sublimation, at about −78 °C (−109 °F). That is what makes it useful: it holds a payload in the deep-frozen range for as long as some of it is left, and it leaves no liquid behind. It is also what makes it a hazard in transport, in two ways.

Pressure

the gas has to go somewhere. US rules require dry ice going by air or water to be packed in packaging designed to release the carbon dioxide gas, to prevent a buildup of pressure that could rupture the package.

Asphyxiation

carbon dioxide is colorless, odorless, and about one and a half times as dense as air, so it collects in low and closed spaces such as a hold, a trailer, or a cold room. The US workplace exposure limit is 5,000 parts per million (ppm) averaged over a working day, and the US National Institute for Occupational Safety and Health (NIOSH) sets 40,000 ppm as immediately dangerous to life or health. Dry ice also causes frostbite on contact.

WHO's guidance on storage and distribution asks for special care when dry ice and liquid nitrogen are used in shipping containers, both for safety and because of possible adverse effects on the quality of the product.

In the dangerous goods lists, dry ice is UN 1845, with the proper shipping name "Carbon dioxide, solid" or "Dry ice", in Class 9, miscellaneous dangerous goods.

Marking and labeling for air: IATA Packing Instruction 954

Air transport of dangerous goods follows the International Civil Aviation Organization's (ICAO) Technical Instructions. The International Air Transport Association's (IATA) Dangerous Goods Regulations (DGR) incorporate them and add the airlines' own requirements; the 67th edition has applied since 1 January 2026. Dry ice is packed under Packing Instruction 954.

The DGR is sold rather than published, so the requirements below are taken from what IATA publishes for free (its conformity checks job aid and the 2026 addendum) and, where marked, from the US rules for air.

No Shipper's Declaration

IATA lists dry ice among the shipments that do not need a Shipper's Declaration for Dangerous Goods; the air waybill entry above takes its place. If the payload is itself dangerous goods, such as an infectious substance, the payload's own rules apply as well.

Quantity per package

the ICAO Technical Instructions, which the DGR incorporates, allow up to 200 kg of dry ice per package under Packing Instruction 954 on both passenger and cargo aircraft, and the US Hazardous Materials Table sets the same limit. Under the US rules, the limit does not apply to dry ice cooling non-hazardous goods in a unit load device that is identified to the operator and vents. Airlines can be stricter: each files its own operator variations in the DGR, and dry ice is one of the subjects they cover.

Arrangements with the airline

under the US rules for air, the shipper has to make arrangements with the operator for each shipment of dry ice.

In the US: 49 CFR 173.217

In the US, the Pipeline and Hazardous Materials Safety Administration's (PHMSA) Hazardous Materials Regulations set the rules, in Title 49 of the Code of Federal Regulations (CFR). Section 173.217 is the one for dry ice, and the Hazardous Materials Table decides when it applies.

By road or rail

the table marks dry ice with "A" and "W": it is subject to the regulations only when it goes by aircraft or by vessel. A truck or rail shipment of dry ice is outside them, although a carrier can still set rules of its own.

By air

the net mass of dry ice is marked on the outside of the package, or of a unit load device that serves as the packaging. Shipping papers can be replaced by other written documentation that gives the proper shipping name, Class 9, UN 1845, the number of packages, and the net quantity of dry ice in each.

Up to 2.5 kg per package

dry ice of 2.5 kg (5.5 lb) or less per package, used as a refrigerant for the contents of the package, is excepted from all the other requirements, provided the package vents and is marked "Carbon dioxide, solid" or "Dry ice", with the name of the contents being cooled and the net weight of dry ice, or a statement that it is 2.5 kg or less.

For diagnosis or treatment

dry ice cooling material shipped for diagnostic or treatment purposes, such as frozen medical specimens, is excepted from the shipping paper and certification requirements, provided the package vents, the operator has agreed to carry it, and the package is marked as dry ice and as being transported for diagnostic or treatment purposes.

Sizing the packout: how long dry ice lasts

Dry ice is a coolant that runs out. The payload stays cold only while some is left, and it sublimes the whole time, at a rate set by the insulation, the ambient temperature along the route, how much was packed, and how long the shipment takes. No regulation gives a figure for how long dry ice lasts. Carrier and supplier pages quote a number of pounds per day; treat it as a starting point for testing, not a sizing rule, because the duration is a property of a qualified packaging system on a known lane.

The World Health Organization (WHO) asks for exactly that. Insulated passive containers are qualified together with everything packed in them, dry ice included, and the qualification records the packing assembly, how the coolant is conditioned, the minimum and maximum load, where temperature monitors go, and the ambient profile of the route from departure to arrival in the recipient's store. A planned packout follows from it:

1. 1

   Qualify for the lane

   Test the shipper with its dry ice load against the route's real ambient profile and its longest realistic transit, delays included.

2. 2

   Pack to the qualified configuration

   WHO asks for containers packed in the exact specified configuration. Less dry ice, a different shipper, or a heavier payload is a different system.

3. 3

   Plan the replenishment

   If a shipment can outlast its dry ice, decide in advance where it can be re-iced and who does it, so a delay is a task rather than a loss.

4. 4

   Count the weight

   Every kilogram of dry ice is declared on the package and the air waybill and counts toward the per-package limit, so the margin is paid for on every shipment.

What the temperature record has to show

The rule is the same as for a refrigerated product. In the EU's good distribution practice guidelines, it should be possible to demonstrate that the medicines have not been exposed to conditions that may compromise their quality and integrity, and customers can ask for that information. The ranges for frozen and deep-frozen products are in our guide to pharmaceutical transport.

At these temperatures the limit is often a ceiling. The US prescribing information for one approved chimeric antigen receptor T-cell (CAR-T) therapy, a cancer treatment made from a patient's own immune cells, says it is supplied in a liquid nitrogen dry shipper at or below −150 °C and stored at or below −120 °C. A record that answers to a limit like that shows:

The product, not the coolant

a sensor resting on the dry ice reads the dry ice. The reading that matters is where the product is, which is why WHO makes the placement of the monitor part of the qualification.

The whole journey

from packout to receipt, with no gap at the handovers, so a warm hour on a dock or a late re-icing is in the record rather than inferred.

A calibration that covers the range

WHO asks for multiple-use devices to be calibrated against a traceable reference once a year, unless otherwise justified, and for the calibration to show accuracy across the entire range over which the device is used. A calibration at refrigerated temperatures says nothing about a reading at −78 °C.

If the record shows the limit was crossed, it is handled like any other excursion: reported, the product held apart and assessed against its stability data. That process is in our guide to temperature excursions, and what an electronic record has to hold up to, from audit trails to access, in our guide to data integrity for temperature records.

Measuring at −80 °C and below

Dry ice, and liquid nitrogen even more, test a temperature monitor in three places:

The sensor's range

check that the sensor is specified and calibrated below the coldest temperature the payload will see, with calibration points near the temperatures that matter.

The device and its battery

a device's electronics have their own operating range, which can be narrower than the probe's. The datasheet should state both, and say what happens to logging, reporting, and battery life at the edge of each.

The probe

for dry ice and liquid nitrogen the usual answer is an external probe: the probe's tip goes with the product and the device stays outside the coolant, on a cable path that does not compromise the shipper's insulation or its venting.

A device that travels by air with a battery has rules of its own, set out in our guide to pharmaceutical transport. How the device types differ, from single-use devices to ones that report in transit, is in our guide to cold chain monitoring devices.

Going colder: liquid nitrogen dry shippers

Some cell and gene therapies have to stay colder than dry ice can hold them, such as the CAR-T therapy above, shipped at −150 °C or below. They travel in dry shippers: insulated containers whose porous absorbent is charged with liquid nitrogen, so the product sits in cold nitrogen vapor rather than in the liquid.

Liquid nitrogen itself is dangerous goods, UN 1977, a nonflammable gas in Division 2.2. A properly prepared dry shipper is treated differently. IATA lists Special Provision A152, for dry shippers containing refrigerated liquid nitrogen, among the provisions under which a shipment can be not subject to its regulations when the conditions are met. The full conditions are in the DGR. The US equivalent, special provision 346, states the central one: the liquid nitrogen must be fully absorbed in a porous material, and the receptacle must hold no hazardous materials other than the nitrogen.

Free liquid in the shipper puts it back under the dangerous goods rules, so the charging and draining steps in the shipper's instructions are part of compliance, not only of performance. And the provision covers the refrigerant: a payload that is dangerous goods in its own right carries its own requirements.

Dry ice and cryogenic monitoring at Controlant

For dry ice and liquid nitrogen shipments, Controlant's Saga Dry Ice and Saga Cryogenic devices report temperature, location, and light in real time, measured in the payload through the same PR-T80 probe. The probe reads to −95 °C on Saga Dry Ice, calibrated at −80, −40, and 0 °C and accurate to ±1.0 °C, and to −200 °C on Saga Cryogenic, calibrated at −196, −80, −40, and 0 °C. The device itself rides outside the coolant at −20 to +50 °C; between −30 and −20 °C it still logs, with reduced battery life, but stops reporting in real time. Because the device reports on its wake-up interval and the moment the temperature leaves its limits, a re-icing can be arranged while the shipment is still in transit.