Hibiscus is pleased to introduce Beccy Ricketts as this month’s guest blog contributor. Beccy has been working in the transport industry for more than 25 years, starting her career in the Irish Freight market. In 2002, she set up her own light haulage transport company, ADR Express, specialising in the carriage of dangerous goods, servicing the commercial industry and public sectors. Initially focused on transporting dangerous goods within the UK, the company has since expanded to provide worldwide services.
Dry ice may seem harmless, but its extreme cold and release of carbon dioxide gas create serious transport risks. In this article Beccy explains why correct marking, labelling, ventilation and documentation are essential across road, sea and air transport.
A Cold Start
“To start my swim this winter, I had to break the ice…”
There is nothing quite like the sharp sting of 1.7 °C water biting at your skin as you push aside a crust of ice to begin an open‑water swim. This winter, which was my entry into the lake — a silent, black surface rimmed with frozen plates that cracked as I waded forward.
Cold‑water swimmers learn quickly that winter water demands respect, preparation, and an understanding of what lies unseen beneath the surface. That mindset aligns closely with the world of dangerous goods compliance, especially when working with something as deceptively simple as dry ice (UN1845).
The Hidden Hazards of Dry Ice
Dry ice appears straightforward: an odourless, flavourless, non‑flammable, residue free refrigerant. But in transport, it behaves in ways that demand careful control and – critically – clear identification. As dry ice warms, it sublimates directly into carbon dioxide gas. Even relatively small quantities can release enough gas to significantly displace oxygen in enclosed spaces, creating an invisible asphyxiation hazard. Combined with its extreme temperature of around –78 °C, which can cause severe cold burns, and the risk of pressure build-up in sealed packaging, dry ice presents hazards that are not always immediately obvious.
This is precisely why marking and labelling are not administrative formalities – they are core safety controls.
Across all modes of transport, dry ice carries the same classification: UN1845 – Carbon dioxide, solid (dry ice), Class 9.
However, how this information must be communicated through marking and documentation varies by mode – and those differences matter.
Under ADR, dry ice is not regulated in the same way as many dangerous goods. This sometimes leads to the false assumption that it requires minimal attention. In reality, marking remains one of the most important safeguards.
Packaging must withstand very low temperatures and allow the release of carbon dioxide gas so pressure cannot build up.
Why Marking and Labelling Matter
Just as importantly, packages must be clearly marked with “DRY ICE”, “CARBON DIOXIDE, SOLID”, or the proper shipping name of the cooled goods followed by “AS COOLANT” or “AS CONDITIONER”.
These markings serve a vital purpose: they alert drivers, warehouse staff, emergency responders, and anyone opening the load space to the presence of gas- generating substance that can quickly create an oxygen-deficient atmosphere.
Transporting Dry Ice by Road
If a vehicle or container is not mechanically ventilated or physically separated from the driver’s compartment, ventilation becomes essential. Where load spaces are not fully ventilated prior to departure, the transport document must include the UN number, the proper shipping name, and a note indicating that the dry ice is being used as a coolant or conditioner.
In short, even where ADR obligations are reduced, identification and communication cannot be.
Transporting Dry Ice by Sea
At sea, the IMDG Code follows similar principles but places even greater emphasis on clear external identification. Cargo holds and containers on board ships are often confined environments where carbon dioxide can accumulate unnoticed. Dry ice-cooled consignments must be packed in materials suitable for extreme cold, marked with the correct proper shipping name and clearly identifiable as containing dry ice, even when the dry ice itself is not the main cargo.
Correct marking ensures that ship crews understand ventilation requirements and do not unknowingly enter a space where oxygen levels have been displaced. In a maritime environment, where access can be limited and response times extended, clear marking is one of the simplest and most effective risk controls available.
Transporting Dry Ice by Air
Air transport applies the greatest level of scrutiny – and for good reason. Under IATA Packing Instruction 954, packaging must not only allow the release of carbon dioxide but also must be precisely and consistently marked. Each package containing dry ice must display the proper shipping name, the UN number, and – importantly – the net weight of dry ice in each package.
This weight declaration is critical. It allows operators to calculate the total amount of carbon dioxide that could be released during the flight. Overpacks must show the total net weight of dry ice contained therein.
Even where a Shipper’s Declaration is not required the Air Waybill must still include the number of packages, the proper shipping name, the UN number and the new quantity of dry ice per package.
In aviation, marking is not just about identification – it is about enabling aircraft-level safety decisions.
Why Clear Identification Is More Important Than Ever
Why does marking matter more than ever? Dry ice is widely used across pharmaceuticals, medical diagnostics, food logistics, and temperature-sensitive supply chains. Its familiarity can lead to complacency. But when dry ice is poorly marked or inadequately described, its hazards remain hidden until conditions become dangerous.
Clear, accurate marking and labelling warn of invisible risks, trigger ventilation and handling precautions, support emergency response and enable compliance across multiple transport modes.
Respect the Hazard
Much like stepping onto winter ice, safety depends on knowing exactly what you are dealing with before you move forward.
Both winter swimming and dangerous goods handling rely on the same principles:
• Know the environment
• Respect the hazard
• Prepare properly
• Act with discipline
Marking and labelling are how communication happens in transport. They are not box-ticking exercises – they are the equivalent of checking the ice before you take the plunge.
Safety is not about eliminating risk. It is about making sure everyone can see it, understand it, and manage it with confidence.
