Short answer: Liquid carbon dioxide (CO₂) decontamination is a specialized cleaning process that uses carbon dioxide held under pressure in liquid form to treat contaminated protective equipment. The system brings the cleaning medium into contact with the gear to help remove targeted contaminants. The process, equipment, and demonstrated results vary, so fire departments should evaluate the specific technology, supporting tests, and applicable PPE-care requirements before choosing a provider.
A fire is out. The crew is back at the station. The gear comes off, the apparatus gets checked, and everyone starts thinking about the next call.
But the work of managing contamination is not necessarily finished when the emergency ends.
Firefighter turnout gear can carry substances from smoke, burning materials, and other incident exposures. Routine washing is an essential part of equipment care, but departments may also need to consider whether additional cleaning processes are appropriate for their gear and exposure profile.
Liquid CO₂ decontamination is one option attracting attention in the fire service. Understanding how it works, what the technology can offer, and where its limitations lie helps department leaders make informed decisions.
What is liquid CO₂ decontamination?
Liquid CO₂ decontamination uses carbon dioxide maintained in a liquid state under pressure as a cleaning medium.
Carbon dioxide is familiar as a gas at ordinary room conditions. Under the right pressure and temperature, however, it can exist as a liquid and be used in specialized cleaning equipment.
In these systems, the liquid CO₂ is brought into contact with the items being treated. The process is designed to help dislodge or dissolve targeted contaminants and carry them away from the material being cleaned.
Unlike conventional water-based laundering, the cleaning medium is carbon dioxide rather than a water-and-detergent mixture. The process takes place inside specialized equipment designed to control pressure, circulation, and other operating conditions.
Cool Clean Technologies manufactures liquid CO₂ cleaning systems, including equipment intended for firefighter protective gear. Its technology overview explains the basic cleaning process and how the system manages CO₂ during treatment. Learn more about liquid CO₂ cleaning technology from Cool Clean.
How does the CO₂ cleaning process work?
The details depend on the particular machine and treatment process, but several basic steps help explain the technology.
1. Gear is prepared for treatment
Before equipment enters a specialized cleaning system, the service provider must identify what is being treated and determine whether the items are appropriate for that process.
Firefighter PPE includes different materials, layers, closures, and components. A coat, pair of pants, hood, and gloves may have different care considerations.
The provider should follow the equipment manufacturer’s instructions and the applicable requirements for inspection, cleaning, and maintenance. The condition of the gear and the nature of its contamination may also affect the service selected.
2. CO₂ is maintained in liquid form
The machine controls pressure and temperature to keep carbon dioxide in the state required by its cleaning process.
That controlled environment allows the equipment to use liquid CO₂ as its cleaning medium. The machine is specifically engineered to operate under those conditions; this is not a process that can be replicated with ordinary carbon dioxide containers or improvised equipment.
3. The cleaning medium contacts the gear
The system circulates or otherwise moves liquid CO₂ through the treatment chamber, bringing it into contact with the materials being cleaned.
Cool Clean describes the low viscosity and surface tension of liquid CO₂ as properties that help its systems move through complex spaces and between layers of material. The degree to which a particular process reaches contaminants within a garment depends on the equipment design, operating conditions, garment construction, and treatment method.
That distinction matters for firefighter PPE. Protective ensembles contain multiple layers with different functions, and the presence of a cleaning medium around a garment does not, by itself, prove that every contaminant has been removed.
4. The process removes targeted contamination
During treatment, the cleaning process is designed to separate targeted contaminants from the material and carry them away.
The outcome depends on the substances involved and the process used. Results for one contaminant cannot automatically be applied to another, and performance data from one system should not be treated as proof of the performance of every liquid CO₂ machine.
This is why departments should look for testing that identifies the contaminants evaluated, the equipment and process used, and the measured results.
5. The CO₂ is recovered or released according to the system design
Many industrial liquid CO₂ cleaning systems use a closed-loop design that recovers and reuses the carbon dioxide. At the end of a treatment cycle, the machine manages the CO₂ according to its engineered process.
Cool Clean describes its liquid CO₂ cleaning technology as a closed-loop process that recaptures and reuses CO₂. Exact operating and recovery arrangements depend on the equipment.
The treated gear must still be handled, inspected, and returned to service in accordance with applicable procedures. A completed cleaning cycle does not replace any required inspection, maintenance, or other PPE-care steps.
Why use liquid CO₂ for firefighter gear?
The potential value of liquid CO₂ decontamination comes from the properties of the cleaning medium and the capabilities of the specific system.
An alternative to water-based cleaning
Liquid CO₂ systems use a different cleaning medium from traditional water-based extractors. That gives departments another option to evaluate when considering how to address contamination on protective equipment.
The distinction is especially relevant when a department wants to understand how different processes perform against particular substances. The right comparison depends on actual test results, not simply whether a process uses water or CO₂.
Potential to address contaminants within layered garments
Firefighter turnout gear is designed with multiple layers that serve different protective functions. Contaminants may remain on surfaces or within materials after an incident.
Liquid CO₂ system manufacturers describe the properties of the medium as helping it move between layers of protective clothing. However, departments should look for evidence demonstrating performance on relevant materials and contaminants rather than assume that a process reaches or removes everything within a garment.
Different equipment and service configurations
Liquid CO₂ technology is not a single, universal process. Systems can differ in design, operating method, and intended application.
For example, Cool Clean offers multiple CO₂ system configurations, including systems with different water-use requirements. The appropriate configuration and service process must be evaluated against the applicable PPE-care requirements.
What does the testing show?
One of the most important questions for any department considering advanced decontamination is whether the process has demonstrated the performance being claimed.
Emergency Technical Decon (ETD) publishes results from testing of its Liquid CO₂+ process. Its reported findings include removal of 84% of tested per- and polyfluoroalkyl substances (PFAS), 99.9% of tested semivolatile organic compounds (SVOCs), 99.8% of tested heavy metals, and 99.9999% of tested biological contaminants.
These are provider-specific results for the contaminants and process tested. They should not be generalized to every liquid CO₂ system, every contaminant, or every set of operating conditions. Review ETD’s published testing and study results.
For department leaders, the useful questions go beyond a single percentage:
- Which specific substances were tested?
- What gear materials and treatment conditions were used?
- How were the results measured?
- Who conducted or verified the testing?
- What limitations did the testing identify?
- Does the evidence apply to the service being proposed for your department?
A credible evaluation connects the performance claim to the actual test. It also recognizes that removing a contaminant from gear is not the same as proving a reduction in an individual’s long-term disease risk.
Does liquid CO₂ replace traditional turnout gear washing?
Not automatically. Routine cleaning remains an essential part of firefighter PPE care, and departments must continue to follow applicable standards and manufacturer instructions.
The National Fire Protection Association’s (NFPA) 2025 edition of NFPA 1850 addresses the selection, care, and maintenance of protective ensembles for structural and proximity firefighting and self-contained breathing apparatus. It consolidates the previous NFPA 1851 and NFPA 1852 standards. The 2025 edition also addresses cleaning verification and specialized cleaning processes.
Departments should evaluate a particular liquid CO₂ system and service process against the requirements that apply to their equipment. A technology label alone does not establish compliance.
To understand how these approaches compare in practice, read Article 4: Traditional Washing vs. Liquid CO₂ Decontamination for Firefighter Gear.
How can departments evaluate a liquid CO₂ provider?
Before selecting a provider, fire chiefs and PPE officers should evaluate both technical qualifications and practical service delivery.
Consider these questions:
- Equipment certification: Does the provider use equipment that meets the program’s required certification and qualification criteria?
- Process evidence: Can the provider document the process used and supply relevant performance testing?
- PPE compatibility: Is the service appropriate for the specific gear and its manufacturer instructions?
- Inspection and maintenance: Can the provider support required inspections and identify equipment that needs further attention?
- Logistics: What are the costs, transportation requirements, turnaround times, and reporting arrangements?
- Standards: Can the provider explain how its process fits within applicable PPE-care requirements?
Afterburn’s provider qualification model is based on equipment certification and performance, not simply on a brand name. Departments should confirm that the specific equipment and service meet the program’s current requirements.
What if advanced decontamination is outside your budget?
A department can understand the potential value of an additional cleaning option and still struggle to pay for it.
That is particularly relevant for departments managing limited operating budgets, long transportation distances, or competing equipment and staffing needs. The challenge is not necessarily a lack of interest in gear care. It may be a lack of access to a service that fits the department’s financial and operational circumstances.
The Afterburn Foundation helps qualifying fire departments access advanced PPE decontamination when cost stands in the way. Afterburn raises philanthropic funding and connects qualifying departments with qualified independent service providers. It does not manufacture equipment or operate a cleaning facility.
Its annual sponsorship model is straightforward:
$500. One firefighter. One year.
A $500 sponsorship provides one firefighter with one year of funded access to qualifying advanced PPE decontamination services. The standard annual service model is designed around two advanced CO₂ decontamination cycles and one annual advanced inspection, with flexibility to fund services according to actual need.
Funding is pooled, allowing services and costs to vary according to equipment, exposure, geography, and logistics. The sponsorship is a commitment to annual access, not a guarantee that every firefighter will receive an identical package of services.
Frequently asked questions
What is liquid CO₂ decontamination?
It is a specialized cleaning process that uses carbon dioxide maintained in liquid form under pressure to treat contaminated equipment. The specific process and its performance depend on the system and contaminants involved.
How does liquid CO₂ remove contaminants from firefighter gear?
The system brings liquid CO₂ into contact with the gear to help separate targeted contaminants from the material and carry them away. The results depend on the equipment, treatment process, contaminant, and supporting evidence.
Is liquid CO₂ decontamination better than water washing?
Neither method should be declared universally superior without specifying the contaminant, equipment, and process being evaluated. Routine washing remains essential, while advanced CO₂ decontamination provides another option for departments to assess using relevant performance testing.
Does liquid CO₂ decontamination prevent firefighter cancer?
No. A cleaning process should not be represented as preventing cancer. Testing may demonstrate reductions in particular contaminants, but that does not establish that the process prevents cancer or eliminates occupational exposure risks.
Can a fire department receive funding for liquid CO₂ decontamination?
The Afterburn Foundation helps qualifying departments access advanced PPE decontamination when cost is a barrier. Departments can apply for funding to have their needs evaluated.
Better decontamination shouldn’t depend on your department’s budget.
Afterburn helps qualifying fire departments access advanced PPE decontamination when cost stands in the way.
Help another department get access: Sponsor a Firefighter
