As a result of dry ice in a sample container causing an explosion at a pathology lab, WorkSafe has issued a reminder to employers about the requirements for the transport, storage and handling of dry ice.
The dry ice had been placed inside a sealed container with a specimen for transport to the pathology lab when the carbon dioxide gas produced by the dry ice caused a rapid increase of pressure and the container exploded. No injuries resulted from this incident, but damage did occur to a ceiling tile and to a pipe under a sink. After the incident the area required decontamination.
When dry ice (solid carbon dioxide) is exposed to room temperatures it transitions from a solid state to a gas state. During this sublimation process the dry ice is converted into carbon dioxide (CO2) gas, with 1kg of dry ice expanding to 760 litres of CO2. If dry ice is stored in a sealed container, as the temperature increases so does the pressure inside the container until a failure of the container occurs. Failure of the container may result in injuries from fragmentation or pressure waves.
Carbon dioxide is a dangerous gas – it is colourless and relatively odourless, and as it is heavier than air it can pool in low areas and accumulate in confined spaces. Exposure to CO2 can cause dizziness, headaches, breathing difficulties, loss of consciousness or death by asphyxiation. Skin contact can result in frostbite and cold burns.
Dry ice should be stored in insulated containers like Styrofoam or thick plastic to slow down sublimation. Never use airtight containers, as the expanding CO₂ gas will cause pressure buildup and potentially explode. Containers should have vented lids to allow gas to escape. When transporting specimens, dry ice must be placed outside of the airtight specimen container and inside ventilated packaging, such as a polystyrene box with visible venting holes. Dry ice must always be stored in a well-ventilated place.
Always use insulated or cryogenic gloves when handling dry ice, and ensure gloves are loose-fitting for quick removal in emergencies. Tongs can also be used to move pieces safely. Eye protection, such as safety glasses with side shields or a full face shield, is recommended to prevent injury from fragments or chips. Wear long-sleeved shirts and trousers to protect exposed skin from accidental contact.
WorkSafe offers guidance to employers in workplaces where dry ice is used:
- Follow the guidance of the Dangerous Goods Act and Regulations and the Code of practice: The storage and handling of dangerous goods when handling dry ice.
- Use transparent soft packaging for the specimen where possible (e.g. bio-pouches) to enable visual checks and reduce projectile risk.
- Prior to dispatch ensure dry ice is easily identifiable with the correct dangerous goods labels and dangerous good documentation attached. (see infographic below)
- Ensure safety data sheets are up to date and available to employees, contactors and emergency services personnel.
- Store dry ice receptacles in a dry well-ventilated area away from areas of heavy pedestrian traffic, emergency exits and protected from impact.
- Provide appropriate personal protective equipment for employees working with dry ice including gloves and eye protection.
- Provide adequate information, instruction and training in relation to the hazards associated with dry ice and its safe use, handling and storage.
- Have policies and procedures for working with dry ice including what to do if you suspect a container has become pressurised, such as segregating, evacuating and initiating emergency responses.
- Ensure emergency management procedures are in place for areas where dry ice may be in use including spill containment and first aid processes.
Read more: Working with dry ice | WorkSafe Victoria