What Is Dry Ice Marking? Shipping Definition And Core Requirements

Dry Ice Marking A package marking identifying dry ice used as a refrigerant; dangerous-goods rules may require additional information such as the proper shipping name, UN number, and net quantity.

Dry ice (solid carbon dioxide) is commonly used to keep temperature-sensitive goods cold during transport. When a package contains dry ice as a refrigerant, it must carry a clear dry ice marking so handlers, carriers and emergency responders know a hazardous solid is present and what precautions to take.

What The Marking Typically Shows

Markings vary by mode and regulation, but they generally communicate three things: the identity of the substance, its UN number and the net quantity. In practice that looks like a statement of the proper shipping name (for example, "Carbon Dioxide, Solid" or "Dry Ice"), the UN number (UN 1845), and the amount of dry ice in the package expressed as a net weight.

• Proper Shipping Name: Identifies the material so carriers and responders can look up handling and emergency measures.
• UN Number: UN 1845 is the standard identifier for dry ice used in dangerous-goods documentation and placarding.
• Net Quantity: The weight of dry ice in the package (commonly quoted in kilograms for air transport).

Why The Marking Matters

Dry ice sublimates to carbon dioxide gas. In confined spaces—truck trailers, vans, aircraft cargo holds—CO2 can displace oxygen and create an asphyxiation hazard; it can also create pressure build-up in tightly sealed packaging. Markings warn handlers to ventilate, avoid enclosing the package in air-tight containers, and follow carrier-specific loading rules. Accurate markings also ensure compliance with dangerous-goods rules and avoid shipment delays or rejected consignments.

How It Varies By Mode Of Transport

Regulatory frameworks differ for road, air and sea. Air transport (IATA/ICAO) is the most prescriptive and usually requires the net quantity on each package. Maritime transport follows the IMDG Code and requires similar identity and UN information. Domestic highway shipments in the United States fall under DOT/PHMSA rules and may have different marking and documentation thresholds depending on the quantity and whether other dangerous goods are present.

• Air: Carriers require the proper shipping name, UN number and net quantity; airlines may also set limits on per-package amounts and require specific handling statements.
• Sea: IMDG expects the UN number and proper shipping name and will treat dry ice as a Class 9 (miscellaneous) hazard for stowage and segregation.
• Road/Rail: DOT/PHMSA regulations require accurate identification and may impose documentation and driver notification requirements for certain shipments.

Who Is Responsible For Marking

The shipper bears primary responsibility for correctly marking and declaring dry ice on the package and on the transport documents. Carriers verify compliance and may refuse improperly marked or documented shipments. Warehouse and fulfillment teams should train packers to apply markings and record the exact net quantity added to each box.

Practical Example For A Fulfillment Operation

A fulfillment center packing frozen samples adds 3.5 kg of dry ice to a corrugated box and places a label that reads: "Dry Ice (Carbon Dioxide, Solid), UN 1845, Net: 3.5 kg." The packer records the net quantity in the order notes and adds the handling statement required by the carrier. When the driver inspects the pallet, the marking and documentation are visible; the shipment proceeds without delay.

Tips To Stay Compliant

• Train Staff: Ensure packers and shipping clerks know how to calculate and record net quantity and apply the correct label.
• Check Carrier Rules: Airlines and some couriers have additional limits and forms—always consult carrier dangerous-goods guidance before tendering.
• Use Durable Labels: Markings must be legible throughout transit; use weather- and abrasion-resistant labels placed on the same surface as other shipping information.
• Document Accurately: Match the package marking to the transport document and any shipper's declaration to avoid inspection failures.

In short, the Dry Ice Marking is a concise, visible statement on a package that identifies dry ice used as a refrigerant and supplies regulators and carriers with the information they need—most importantly the proper shipping name, UN number and the net quantity—so shipments move safely and compliantly.