How to Label a Package with UN1845 Dry Ice – 2025 Guía

Properly labeling packages containing dry ice (UN1845) is essential for safety, compliance and efficiency in cold‑chain logistics. La Asociación Internacional de Transporte Aéreo (IATA) y los EE. UU.. Departamento de Transporte (PUNTO) require that packages allow carbon‑dioxide gas to vent to prevent ruptures. Además, each package must display the proper shipping name (Dry ice or Carbon dioxide, sólido), el número de la ONU (Y 1845), una clase 9 etiqueta de peligro, the net weight in kilograms and the shipper and consignee addresses. This guide will walk you through each element of a compliant label and highlight the latest 2025 tendencias.

• Why correct labeling matters for UN1845 dry‑ice packages – understand the risks of CO₂ build‑up and the legal consequences of improper markingfedex.com.

• What information must appear on the label – including the proper shipping name, Número de la ONU, net weight and hazard symbol.

• Cómo dimensionar, position and print labels – discover label dimensions, minimum text heights and placement rules.

• Mode‑specific requirements for air, ground and postal services – learn how weight limits and documentation differ between IATA, USPS and DOT guidelines.

• Common mistakes and best practices for durable, legible labels – avoid frequent errors such as writing inside the hazard diamond or failing to vent packagesshipmercury.com.

• Emergente 2025 trends in dry‑ice logistics – from digital acceptance checklists to sustainable packaging and IoT trackingtrackonomy.ai.

Why does proper labeling matter for UN1845 dry‑ice shipments?

Dry ice is hazardous if mishandled

hielo seco (dióxido de carbono sólido) sublimates to gas at −78.5 °C. If it is enclosed in a sealed container or thick metal drum, gas pressure can build up and rupture the packagingfedex.com. This risk is why regulations require vented packaging for all dry‑ice shipmentsecfr.gov. In confined spaces such as aircraft holds, carbon‑dioxide accumulation can displace oxygen and pose asphyxiation hazardshazmatuniversity.com. Proper labeling warns handlers of these hazards and ensures that packages are stowed and ventilated correctly.

Regulatory compliance avoids fines and delays

Dry ice is classified as a Class 9 “miscellaneous dangerous good” under the UN model regulations and IATA Dangerous Goods Regulations. Failing to label packages with the UN number, hazard class and net weight may result in rejection by carriers or regulatory finesfedex.com. Some carriers, como FedEx, require packages to pass a detailed acceptance checklist that checks for UN 1845 marcas, proper shipping names, net weight and Class 9 etiquetasfedex.com. Non‑compliant shipments may be embargoed or returned to the shipperfedex.com. Correct labeling therefore protects your shipment from costly delays and ensures the safety of logistics personnel.

Labeling communicates critical information

Clear labels tell handlers the nature of the contents, the weight of dry ice and any special handling needs. This information helps carriers arrange for proper ventilation and track the quantity of hazardous material loaded on an aircraftdess.uccs.edu. In an emergency, responders can quickly identify the hazardous substance and consult safety procedures. Proper labeling is not only a legal obligation but a way to protect your product and everyone who handles it.

What information must appear on a UN1845 dry‑ice label?

A compliant label contains six core elements. Each element is mandated by IATA, USPS or DOT regulations and must be durable, legible and affixed on the package (not on a pouch)fedex.com.

Additional documentation on the air waybill

When dry ice is used as a refrigerant for non‑dangerous goods, a Shipper’s Declaration is not required. Sin embargo, the air waybill or electronic equivalent must include the UN number, nombre de envío adecuado, number of packages and net weight of dry icedess.uccs.edulion.com. Por ejemplo, the entry might read:

Failing to include this information on the air waybill can lead to rejection at the acceptance pointdess.uccs.edu.

Cómo dimensionar, position and print UN1845 labels

Label size and text height

Regulations specify the minimum size of the hazard diamond and the text height for UN numbers:

• Clase 9 etiqueta de peligro: Must be at least 100 mm × 100 milímetros (cuadrado) and placed on a vertical sidetempcontrolpack.com.

• UN number text height: 12 mm for packages over 30 kilos; 6 mm for packages 5–30 kg; adequate size for packages under 5 kilosfedex.com.

• OVERPACK marking: If an overpack hides inner labels, the word “OVERPACK” must appear in letters at least 12 mm hightempcontrolpack.com.

These dimensions are common failure points in carrier acceptance checks, so measure your labels before printingtempcontrolpack.com.

Placement rules

1. Same surface requirement: The proper shipping name and UN 1845 should be on the same surface of the package as the Class 9 hazard label when space allowsshipmercury.com.

2. Vertical orientation: Affix the hazard label on a vertical side; avoid placing it on the top or bottom where it can be obscuredfedex.com.

3. No overlap: Labels must not cover or obscure other required markingsfedex.com.

4. Direct application: Self‑adhesive labels must be attached directly to the package; do not place them inside plastic pouches or under shrink wrapfedex.com.

Printing and materials

For cold‑chain shipments, choose durable materials and adhesives that withstand sub‑zero temperatures:

• Use freezer‑ or cryo‑rated adhesives that remain sticky at −78.5 °C. Resin or wax‑resin thermal transfer ribbons provide moisture and abrasion resistance.

• Apply labels to dry, unfrosted surfaces to avoid edge lift; use a label backer on textured corrugate for better adhesiontempcontrolpack.com.

• Avoid ordinary office labels; they may curl or fall off when exposed to condensation during thaw cycles.

Paso: Building a compliant UN1845 label

Follow this process each time you prepare a package with dry ice:

1. Pesar el hielo seco: Use a calibrated scale to determine the net weight. Record the weight in kilogramsshipmercury.com.

2. Print the core text: On the label, print “Dry ice” or “Carbon dioxide, solid” and the UN number “UN 1845.” Ensure the UN text height meets size requirementsairseacontainers.com.

3. Add the net weight: Write the net weight (p.ej., “5 kg”) outside the hazard diamond. Hacer no write the weight inside the diamond borderfedex.com.

4. Ajuste la clase 9 etiqueta: Apply a 100 mm × 100 mm hazard label on a vertical side of the packagetempcontrolpack.com.

5. Mark shipper and consignee addresses: Use durable ink or a printed shipping label to mark the names and addresses on the packagefedex.com.

6. Aventar el paquete: Confirm that your packaging allows CO₂ to vent—do not seal all seams or place dry ice in sealed bagsfedex.com.

7. Complete the air waybill (Si corresponde): In the “Nature and Quantity of Goods” field, enter “UN1845, hielo seco, X packages × Y kg”dess.uccs.edu.

8. Check for overpacks: If you place multiple packages in an overpack and inner labels are not visible, mark “OVERPACK” in ≥12 mm letters and show the total net weight of dry ice on the overpacktempcontrolpack.com.

9. Inspect before shipping: Use an acceptance checklist similar to FedEx’s to verify that all markings and labels are present and legiblefedex.com.

Mode‑specific labeling requirements

Different transport modes impose additional restrictions and documentation. Understanding these differences will help you avoid surprises at the shipping counter.

Carga aérea (Aquí/icao)

• Weight limits: Instrucción de embalaje de IATA 954 allows up to 200 kg of dry ice per package for passenger and cargo aircrafthazmatuniversity.com. Operators may impose lower limits—some carriers cap packages at 68 kilostempcontrolpack.com.

• Ventilación: Packages must be designed and constructed to allow CO₂ releasedess.uccs.edu. Shippers must arrange with the carrier to ensure ventilation procedures are followeddess.uccs.edu.

• Documentación: When a Shipper’s Declaration is not required, the air waybill must list UN 1845, the proper shipping name, number of packages and net weightdess.uccs.edu.

• Declaration required with dangerous goods: If dry ice is used to refrigerate dangerous goods, a Shipper’s Declaration is mandatoryhazmatuniversity.com.

• Operator variations: Check each airline’s operator variations (p.ej., AM‑09, AS‑11) to confirm venting procedures and weight limitsdess.uccs.edu.

USPS domestic mail

The United States Postal Service permits dry ice in domestic mail under strict conditions. Para transporte aéreo, mailpieces may contain no more than 5 libras (≈2.27 kg) de hielo secope.usps.com. For surface mail, packages may exceed 5 libras, but international mail is prohibitedpe.usps.com. Each mailpiece must be clearly marked on the address side with the contents being cooled and the net weight of the dry icepe.usps.com. Air‑transport mail must bear a Class 9 label and be marked “Carbon Dioxide Solid, UN1845” or “Dry Ice, UN1845”pe.usps.com. Surface‑transport mail must show “Surface Mail Only” along with the proper shipping name and UN numberpe.usps.com.

Ground transport (DOT/49 CFR)

En los Estados Unidos, dry ice is not regulated as hazardous by road or rail when used as a refrigerant, provided packages are vented and marked appropriately. The net mass of dry ice must be marked on the outside of the packageecfr.gov. Dry ice in quantities not exceeding 2.5 kilos (5.5 lb) por paquete is excepted from other requirements if the package is vented and marked with the proper name and net weightecfr.gov. When used for diagnostic or treatment purposes (p.ej., especímenes médicos), dry ice is excepted from shipping paper requirements provided the package is vented and marked accordinglyecfr.gov.

Equipaje de pasajeros

Los pasajeros pueden llevar a 2.5 kilos (5.5 lb) of dry ice in checked or carry‑on baggage with operator approval. The package must permit CO₂ venting and be marked with the net quantity or the statement “2.5 kg or less”. Always contact the airline for approval before travel.

Overpacks and mixed contents (U3373)

When packages containing dry ice are placed in an overpack and the inner labels are not visible, the overpack must be marked “OVERPACK” in letters ≥12 mm and display the total net weight of the dry ice. If dry ice is shipped with UN3373 Biological Substance Category B, both labels—the UN3373 diamond and the Class 9/UN 1845 label—must appear. A Shipper’s Declaration is not required when dry ice is used only as a refrigerant for UN3373tempcontrolpack.com, but the air waybill must note both items.

Operator‑specific notes (Fedex & Unión Postal Universal)

Carriers like FedEx and UPS publish their own job aids. FedEx 2025 checklist requires packages to be in good condition, marked with the shipper and consignee addresses, Y 1845, the proper shipping name, la clase 9 hazard label and the net weight in kilogramsfedex.com. It also prohibits using FedEx‑branded boxes (except for specific Temp‑Assure packaging) and polystyrene foam coolers unless approvedfedex.com. UPS largely follows IATA rules but may set lower weight limits; always check your carrier’s current guidelinestempcontrolpack.com.

Common mistakes and how to avoid them

Mistakes on dry‑ice labels can lead to rejected shipments. Avoid these pitfalls:

• Writing inside the hazard diamond: Never write the net weight or other text inside the Class 9 diamantefedex.com. Keep the symbol clean so inspectors can see it.

• Using pounds only: Regulations require the net weight in kilograms; pounds may be shown in parentheses.

• Forgetting the overpack label: If inner labels are hidden, mark “OVERPACK” and the total net weight.

• Selecting the wrong hazard label: Dry ice uses the generic Class 9 etiqueta; do not use the lithium battery variant.

• Sealing packages airtight: Venting is mandatory. Never tape all seams or place dry ice in sealed plastic bagsfedex.com.

• Missing addresses: Without shipper and consignee addresses, carriers may reject the packagefedex.com.

Use a checklist to verify each element before dispatch. Carriers often inspect all sides of the package, so mark each face clearly and remove any irrelevant or contradictory labelsfedex.com.

Durable materials and adhesives for cold‑chain labels

Extreme cold can cause ordinary labels to curl or detach. To ensure your labels remain intact:

• Elegir cryogenic adhesives rated for temperatures below −78.5 °C; these adhesives maintain tackiness in freezer conditionstempcontrolpack.com.

• Imprimir con cintas de transferencia térmica de resina o cera -resina to resist moisture and abrasion.

• Apply labels on seco, unfrosted surfaces; moisture can prevent proper adhesion.

• When labeling corrugated boxes, usar un flat label backer to prevent edge lift and ensure the label lies flat.

• Store spare labels in a sealed bag to protect them from condensation before use.

2025 trends and innovations in dry‑ice logistics

The cold‑chain industry is evolving rapidly. Staying informed about new technologies and practices can improve compliance and efficiency.

Sustainable packaging

Environmental concerns and stricter regulations are pushing sustainability to the forefront of cold‑chain logisticstrackonomy.ai. Companies are adopting eco‑friendly materials such as recyclable and biodegradable packagingtrackonomy.ai. Sustainable packaging reduces waste, lowers carbon footprints and may appeal to environmentally conscious customers.

Smart monitoring and IoT sensors

Real‑time temperature monitoring helps maintain product quality and ensure regulatory compliance. Advanced IoT‑enabled tracking devices provide continuous visibility into location, temperature and humiditytrackonomy.ai. These systems allow you to adjust shipping routes, avoid delays and document the temperature history of your package, which can be critical for pharmaceuticals and biologicstrackonomy.ai.

Automation and robotics

Labor shortages and the need for efficiency are driving automation in cold‑chain facilities. Automated storage and retrieval systems and robotic handlers streamline processes, reduce errors and improve throughputtrackonomy.ai. Automation also enhances consistency in temperature control and reduces the risk of human error.trackonomy.ai

Artificial intelligence and predictive analytics

AI helps optimize routes, forecast demand and predict equipment maintenance needstrackonomy.ai. Predictive analytics can foresee potential disruptions and propose alternative routes or shipping methods. For dry‑ice shipments, AI can estimate sublimation rates and recommend the amount of dry ice needed to maintain temperature without exceeding weight limits.

Growth in pharmaceutical cold chain

The pharmaceutical sector continues to drive cold‑chain expansion. Gene and cell therapies require ultra‑cold temperatures, increasing the demand for reliable dry‑ice logisticstrackonomy.ai. Ensuring compliant labeling and documentation is crucial in this high‑value sector.

Digital acceptance checklists and eAWB adoption

Carriers are moving toward digital acceptance processes. FedEx 2025 checklist emphasizes electronic records and digital labelsfedex.com. Many carriers accept eAWBs (electronic air waybills) that incorporate the UN 1845 line and net weight automaticallytempcontrolpack.com. Adopting digital documentation reduces paper waste and speeds up acceptance.

FAQ – frequently asked questions

Q1: Do I need a Shipper’s Declaration when shipping dry ice?
If dry ice is used solely as a refrigerant for bienes no expertos, a Shipper’s Declaration is not required. En cambio, include the UN number, nombre de envío adecuado, number of packages and net weight on the air waybilldess.uccs.edu. When shipping with dangerous goods (p.ej., quimicos), you must complete a Shipper’s Declarationhazmatuniversity.com.

Q2: What is the maximum amount of dry ice allowed per package?
Para transporte aéreo, Instrucción de embalaje de IATA 954 permits up to 200 kilos of dry ice per packagehazmatuniversity.com; individual airlines may set lower limits. USPS allows only 5 lb (≈2.27 kg) in air mailpiecespe.usps.com, while passengers may carry up to 2.5 kilos con aprobación de la aerolínea.

Q3: Can I reuse old hazard labels or stick multiple labels on the same package?
Do not reuse labels if they are faded or damaged; all markings must be clear and legible. Remove irrelevant or contradictory labels before shippingfedex.com.

Q4: What happens if I forget to vent the package?
Failure to vent packages can cause pressure build‑up and rupturefedex.com. Carriers may reject sealed packages or return them to the shipperfedex.com.

Q5: Are there alternatives to dry ice?
Sí. Materiales de cambio de fase (PCM) and gel packs are alternatives for moderate temperatures, and some shippers use liquid nitrogen for ultra‑cold conditions. Sin embargo, these require different labeling and handling rules and may not offer the same temperature range as dry ice.

Resumen y recomendaciones

Compliant labeling of UN 1845 dry‑ice packages protects your shipment, ensures safety and prevents costly delays. Remember to:

• Mark packages with “Dry ice” or “Carbon dioxide solid,” “UN 1845,” the net weight (kilos), la clase 9 hazard label and both addressestempcontrolpack.com.

• Use labels with minimum dimensions: 100 mm × 100 mm hazard diamond; UN number text height of 12 milímetros (>30 kilos) o 6 milímetros (>5 kilos)fedex.com.

• Keep labels on the same surface and affix them directly to the package. Do not write inside the hazard diamondfedex.com.

• Vent packages to allow CO₂ to escape and prevent rupturesfedex.com.

• Document the shipment on the air waybill with the UN number, shipping name, number of packages and net weightdess.uccs.edu.

• Mantente actualizado with carrier variations and 2025 trends such as e‑documentation, sustainable packaging and IoT monitoringtrackonomy.ai.

By following these steps and verifying each element, you’ll ensure that your dry‑ice shipments remain safe, compliant and efficient.

Actionable next steps

1. Prepare a label template: Create a reusable template that includes fields for the proper shipping name, Número de la ONU, net weight and addresses. Check that the hazard diamond meets the 100 mm minimum size.

2. Invest in durable materials: Stock cryogenic‑rated labels and thermal transfer ribbons to ensure legibility in sub‑zero conditions.

3. Use digital tools: Adopt electronic air waybills and digital acceptance checklists to streamline documentation.

4. Train your team: Provide hazmat training so employees understand Packing Instruction 954 y variaciones del operadorhazmatuniversity.com.

5. Engage experts: Contact cold‑chain specialists if your shipment involves dangerous goods or international routing.

Acerca de Tempk

Tempk is an innovator in sustainable cold‑chain packaging. We develop insulated containers, reusable ice packs and compliant labels that meet the latest UN1845 and IATA regulations. Our products are designed to allow proper venting of carbon‑dioxide gas and to withstand ultra‑cold temperatures. By combining eco‑friendly materials with smart design, we help shippers maintain product integrity while reducing environmental impact. Si está transportando productos farmacéuticos, food or scientific samples, Tempk offers tailored solutions to keep your cargo safe and compliant.

Ready to upgrade your cold‑chain labeling? Contact us for expert advice and discover how our compliant labels and packaging can simplify your logistics.