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Vaccine storage: A firefighter’s guide to dry ice handling and hazards

As departments are tasked with moving, packing and unpacking the vaccines, firefighters must be mindful of carbon dioxide dangers


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As if firefighters haven’t had to learn enough new information during the pandemic, they must now also become experts the ins and outs of vaccine handling, transport and storage. Within the chain of custody that leads to vaccine distribution, many fire departments are tasked with moving, packing and unpacking the vaccines, plus storing them at or below freezing.

Most firefighters are familiar with freezing cold, hyper- and hypothermic reactions, as well as the signs and symptoms of frostbite. But it is this new realm vaccine-level cold that opens first responders to make mistakes, underestimate the penalty for lackadaisical behavior, and put lives in danger. History requires a more aware approach of working with hazards.

[Read next: Sizing-up the COVID-19 vaccine: Firefighters, researchers separate fact from fiction]

Vaccines require dry ice storage

All vaccines require storage at low temperatures in energy-dependent freezers or room coolers, but the first vaccine issued from Pfizer-BioNTech requires extremely low temps. Specifically, that vaccine requires storage at temperatures of -74 degrees C or colder to maintain its efficacy. The next-generation vaccines, while not as severe with their ultra-cold temperature requirement, must still be stored in a cold environment.

Dry ice is the preferred tool to use in transport and in storage of the COVID-19 vaccines. This is where firefighters are exposed to risk. A chest freezer may use up to 50 pounds of dry ice per day when placed on top of product, whether food or vaccines.

Carbon dioxide is colorless and odorless in low amounts. In high concentrations, carbon dioxide is known to have a sharp acidic odor. When compressed under extreme pressure, it converts into a solid state known as dry ice. If you saw a pound of ice and a pound of dry ice, the dry ice cube would be half the size. CO2 in its solid state is always below -78.5 to -109.3 degrees C.

Dry ice is nothing more than carbon dioxide in solid form. While dry ice may look like ordinary ice, a few seconds of contact with bare skin can result in severe frostbite. Carbon dioxide gas is released directly by dry ice in an “off-gassing” atmospheric process.

The IAFC has identified vaccine distribution, and dry ice in particular, as cause for hazard management – and for good reason. By utilizing dry ice to ensure a viable vaccine for the nation, firefighters are now exposed to this product in greater quantities every day. While the amounts used in transport and storage may be understood as a solid, the real danger is in the conversion of dry ice to carbon dioxide gas. As dry ice “melts,” it converts directly to gas, and therein lays the danger. It has now gone from acrogenic to asphyxiant.

Storage of dry ice requires a cool environment with ventilation, as carbon dioxide is constantly off-gassing proportional to temperature. This creates increased pressure over time, especially in confined spaces – trailer, box or even vials containers. Imagine stacking multiple coolers of vaccine packed in dry ice while blocking any vent holes in a closed freezer. In perfect proportion, carbon dioxide can explode.

Much like carbon monoxide, carbon dioxide displaces oxygen very quickly. In a confined space, an unsuspecting firefighter can be rendered unconscious in minutes. Specifically, in an atmosphere of 21% oxygen (normal circumstances), this would be a 5% reduction in the oxygen percentage of the air that is being breathed. A few minutes at 2% reduction (19% oxygen), you’ll have a headache. When you are at 15% or 16% oxygen in air, then you’re facing a carbon dioxide emergency.

Exposure to concentrated levels of carbon dioxide gas can result in headache, dizziness, difficulty breathing and in extreme cases – convulsion, coma and death. Chronic exposure can cause personality disorders and loss of vision.

Proper handling, plus hazard mitigation

When firefighters must work around dry ice in a well-ventilated area, they should wear gloves, long sleeves and eye protection.

Direct contact with skin is met by removing contaminated clothing, immersing the affected area in warm water and transporting victims to medical facilities. Mucus membranes are extremely sensitive to off-gassing regardless of the amount, and require immediate flushing with water before transport.

If exposure limits are expected to be high, SCBA are required. For physical exposure, gloves, eye protection along with bunkers is acceptable. Level B Tyvek or a similar suit assembly works well as well, but remember, in perfect proportion, carbon dioxide can explode given an ignition source.

In situations where a breach occurs, firefighters must respond to the hazard accordingly. An accurate size-up that considers the amount of product, ventilation opportunities, victims and location is essential for successful resolution of a carbon dioxide emergency. Regardless of the size of the breach, treat dry ice as a hazardous material, maintaining standard protocols for a contaminate.

The mitigation goal for carbon dioxide is to coordinate with command to disperse carbon dioxide safely and effectively while preserving vaccine.

An acronym for dry ice situations

Here’s an acronym for these situations: IVECSNR, with an ironic mnemonic to help – I’VE ConSistently Not Remembered. It stands for: Isolation, Ventilation, Evacuation, Containment, Stabilization, Neutralization and Removal.

  • Isolation: Determine product, amount and ambient temperatures.
  • Ventilation: Visualize a pattern of off-gassing dispersal.
  • Evacuation: Remove potential victims and secure area.
  • Containment: Assess structural integrity and any breeches in containers – focus on salvage.
  • Stabilization: Begin control of material and environment, including vaccine vials accountability and viability.
  • Neutralization: Solve the toxic dispersal challenge, protect the vaccine and provide a safe environment.
  • Removal: Allow for ventilation to completely disperse the off-gassing of carbon dioxide while the vaccine is being relocated.


International Association of Fire Chiefs Hazardous Materials Committee White Paper on Dry Ice (Carbon Dioxide) Response – Nov. 23, 2020

Virginia State Fire Marshal Garrett Dyer and the Virginia Department of Fire Programs’ work: VDFP Cautions Against the Mishandling of Dry Ice Used for Shipping and Storing COVID-19 Vaccines.

Note: The Hazardous Material Information System has a rating scale of 0-4. For carbon dioxide, Health has a risk factor of 3, while Flammability and Physical Hazards are rated at 0. While some disagree with the ratings or their classification, the NFPA numbers align with health and flammability ratings while deeming it stable as a reactant.

Editor’s Note: Has your department be tasked with vaccine storage? Did you feel prepared for the task? Share you experience in the comments below.

Jim Spell spent 33 years as a professional firefighter with Vail (Colorado) Fire & Emergency Services, the last 20 years as a captain. He helped create the first student/resident fire science program west of the continental divide, formed the first countywide hazmat response unit and was on the original Colorado Governor’s Safety Committee. As founder of HAZPRO Consulting, LLC, Spell advised businesses on subjects ranging from hazard analysis and safety response to personnel development and organization. His writing won six IAFF Media Awards. Many of Spell’s articles are available by podcast at His last book was titled “Boot Basics: A Firefighter’s Guide to the Service.” Spell passed away in April 2024 after a short battle with cancer. His last four articles detailed his cancer journey.