Short answer: Do not transport solid carbon dioxide in stowed baggage unless the carrier explicitly permits it. Most major airlines and international rules limit the net quantity to 2.5 kg (5.5 lb) per passenger, require packaging that allows venting, mandatory marking with “UN 1845” plus net mass, and declaration at check‑in.
Packing instructions: Use an insulated inner container for temperature control and a robust outer container that is not airtight so sublimated gas can escape; never seal the package. Affix a hazardous‑materials label reading “Carbon dioxide, solid, UN 1845” and write the exact net weight on the outer surface. Maintain documentation (DGR reference or airline form) accessible at the point of acceptance.
Regulatory overview: International baseline rules come from the IATA Dangerous Goods Regulations; national aviation authorities (FAA, EASA, etc.) and individual carriers may enforce stricter limits or full prohibitions for items carried in the aircraft hold. US Transportation Security Administration guidance allows limited quantities under labeling and packaging requirements, but carrier policies govern final acceptance.
Actionable checklist: 1) Verify the carrier’s policy before travel; 2) Confirm national entry/exit rules for hazardous materials; 3) Limit net mass to 2.5 kg (5.5 lb) per passenger unless a specific approval is granted; 4) Pack in vented, insulated containers with “UN 1845” marking and net weight visible; 5) Declare the shipment at check‑in and retain paperwork; 6) When feasible and permitted, opt for cabin carriage under carrier approval to simplify handling and monitoring.
Which airlines and countries allow solid carbon dioxide in stowed baggage and what are the per-passenger weight limits?
Short answer: most regulators and large carriers permit solid CO₂ in stowed bags at a maximum of 2.5 kg (5.5 lb) per passenger, provided the container allows gas venting, the article is declared and labeled, and any carrier-specific approval is obtained.
Major carriers – common practice and examples
United States: TSA guidance limits to 2.5 kg (5.5 lb) per passenger; major US airlines (American, Delta, United, Southwest, Alaska, JetBlue) follow that limit but require release-vent containers and declaration at check-in. Canada: Transport Canada/IATA-aligned rules – Air Canada and WestJet typically accept up to 2.5 kg with similar packaging and notice requirements. Europe: national aviation authorities and flag carriers (Lufthansa, Air France–KLM, IAG carriers such as British Airways and Iberia) generally accept up to 2.5 kg subject to airline approval and labeling; some low-cost carriers (examples include certain short-haul operators) may forbid carriage or require prior authorization. Middle East / Gulf: Emirates, Qatar Airways, Etihad normally permit up to 2.5 kg after prior notification and with vented packaging. Australia / New Zealand: major carriers (Qantas, Air New Zealand) usually follow the 2.5 kg standard but require airline acceptance and declaration.
Country and regulator notes
International standard: IATA dangerous-goods provisions and many national regulators allow up to 2.5 kg (5.5 lb) per passenger for passenger baggage without full dangerous-goods paperwork. Exceptions and tighter limits occur; some airlines set lower allowances (e.g., 1–2 kg) or ban solid CO₂ entirely on specific routes, especially to/from regional or remote airports. Always check the carrier’s dangerous-goods or special-items page and obtain written approval when required; if the carrier demands advance acceptance, present the item for screening and declaration at departure.
How to package, vent and secure solid carbon dioxide for hold baggage to comply with IATA and airline rules
Packaging and venting
Use a rigid, insulated inner container (expanded polystyrene cooler or purpose-made thermal box) placed inside a firm outer container or suitcase. Inner container must not be airtight: leave the inner lid slightly ajar or provide vents so sublimated gas escapes to the aircraft hold. Drill 6–10 mm ventilation holes in the outer container (at least two opposite sides) or keep zipper gaps unobstructed; never seal with airtight tape or use vacuum-sealed packs.
Limit net mass per passenger to the IATA passenger limit of 2.5 kg (5.5 lb) of solid carbon dioxide unless an airline permit for larger quantities has been obtained. Mark the outer surface with “UN 1845, Carbon dioxide, solid” and the net mass in kilograms (example: “Net mass: 2.5 kg”). Place absorbent padding beneath the inner container to capture condensation from temperature differences.
Securing, labeling and declaration
Stabilize the inner container so it cannot shift: surround with clothes or soft goods and secure with straps or packing inserts. Keep all flammable goods, aerosol cans and lithium batteries separated from the carbon dioxide package. Present the bag at the airline desk for declaration and inspection; staff may require relocation of the package, additional labels, or refusal if packaging is inadequate.
Required markings: “UN 1845” plus the proper shipping name “Carbon dioxide, solid” and the net mass in kilograms on the outside of the bag or box. Add a visible name and contact telephone number. For larger consignments, follow airline-specific paperwork and cargo acceptance procedures under IATA Dangerous Goods Regulations.
For additional odor control or passive filtration of expelled gas near the outer vent, consider adding an activated-carbon filter element; instructions available at how to make a carbon air scrubber.
How to declare and label solid carbon dioxide at check-in: exact wording and documentation staff will expect
Speak clearly at the counter: “Solid carbon dioxide (UN 1845); NET WT X.X kg; packed in a vented rigid container; personal use.”
If staff request a shorter statement for the boarding pass tag or system entry, provide: “UN 1845 – CARBON DIOXIDE, SOLID – NET WT X.X kg – Limited Quantity (passenger aircraft)”.
Exact label text to print and attach to the outside of the bag (use uppercase, durable adhesive):
UN 1845 – CARBON DIOXIDE, SOLID – NET WT ___ kg
PASSENGER AIRCRAFT – LIMITED QUANTITY (only when allowed by airline; if transport is by cargo-only service the agent will instruct alternate marking).
Required information staff will expect on a written passenger declaration form (provide one copy to agent and keep one): name; booking reference; flight number; origin/destination; proper shipping name exactly as “Carbon Dioxide, Solid (UN 1845)”; net weight in kg to one decimal place; number and type of containers (e.g., “1 vented styrofoam box”); certification phrase and signature such as “I declare that the contents are: Carbon Dioxide, Solid (UN 1845); net wt ___ kg; packaged as required by IATA PI 954; for carriage on passenger aircraft.” Add date and passenger signature; agent initials and stamp when accepted.
If multiple inner containers exist, list both total and per-container weights exactly: “Total NET WT 3.0 kg (Container A 1.5 kg; Container B 1.5 kg)”. Use kilograms; do not convert to pounds alone.
If declared amount exceeds the airline’s per-passenger limit or the flight type requires it, staff will request a “Shipper’s Declaration for Dangerous Goods” and airline DG office approval before acceptance.
Label placement and appearance expected by staff: print on white, weatherproof adhesive; font large enough to scan at a glance; attach to the main external panel near the handle or zipper and next to the airline bag tag; include passenger name and booking reference on the same label when requested.
Carry a printed copy of the signed declaration inside the bag and present both copies at check-in. Agents will verify net weight, ventilation of the container, and that the label matches the written declaration before accepting the bag.
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What airport inspections to expect and what to do if solid CO2 causes leaks, odor or pressure in hold baggage
Declare solid CO2 at check-in; expect staff to perform visual inspection, X‑ray screening and possible manual opening in a ventilated area.
- Typical airport checks
- Counter staff: verification of declaration, weight check, visual signs of frost or wetness on outer fabric.
- Security X‑ray: identification of insulated containers, compressed canisters or dense blocks; flagged items may be selected for secondary search.
- Explosive/chemical trace detection (ETD): swab testing of external surfaces if suspicious residue observed.
- Manual secondary inspection: agent will open the bag in a controlled space (behind screen or in a designated inspection room) with PPE if frost or pressure signs exist.
- Operations/fire crew: if significant venting or pressure bulge threatens safety, fire/operations staff may be called to assess and segregate the item from other goods.
- What inspectors look for
- Blocked vents or sealed plastic bags that trap CO2 gas and cause inflation.
- Frost accumulation, pooling liquid from condensed moisture, or strong scent coming from frozen contents (solid CO2 itself is odorless; any smell usually originates from frozen food or packaging).
- Damaged containers, leaking canisters, or signs of recent movement that could rupture a sealed container in transit.
- Immediate steps when leaks, odor or pressure detected
- Move the bag to an open, ventilated space away from passenger flow; keep non‑essential personnel clear.
- Ask staff to open zippers slowly while standing upwind; avoid sudden rupture of sealed compartments that may eject contents.
- Isolate and remove frozen carbon dioxide into an approved vented container or airline-provided bin. Do not place sealed plastic or airtight bags over sublimating material.
- Use thick gloves and eye protection when handling pellets/blocks; avoid skin contact to prevent cold burns.
- When pressure has caused bag distortion or zipper failure
- Do not apply sharp tools directly to the bulging area; request airport staff with appropriate tools and training to make a controlled opening.
- If container rupture has scattered pellets, staff will sweep and collect fragments for safe disposal in a ventilated zone.
- Keep electronic devices and combustible materials away from the immediate area until fragments sublimate.
- If a strong odor is present
- Assume odor originates from frozen merchandise, chemical spills or contaminated packaging; treat as potential contamination until cleared.
- Request agents to separate affected items and, if necessary, label them as hazardous waste for disposal or re‑packaging per airline/airport procedures.
- Health and emergency indicators
- Exposure symptoms: headache, dizziness, shortness of breath, loss of coordination. Any passenger displaying these signs should be moved to fresh air and assessed by medical personnel.
- Severe exposure: call emergency services and notify airport operations about possible asphyxiation hazard in confined zones.
- Paperwork and follow-up
- Request an incident report from the airline and security; retain a copy of the bag tag and any handling notes for claims or regulatory follow-up.
- If airline refuses carriage after inspection, arrange ground disposal or transfer to a service approved to handle sublimating solid CO2; airport operations can advise on permitted options.
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