What cannot be extinguished with a carbon dioxide fire extinguisher: a complete list of prohibitions and alternatives

Why are carbon dioxide fire extinguishers not universal?

Carbon dioxide fire extinguishers (Op-amp) are some of the most common in cars, offices and home garages. They are valued for their compactness, absence of traces after extinguishing and high efficiency against electrical appliances. However CO₂ (carbon dioxide) It does not work with all types of fires - in some cases it is not only useless, but also deadly.

The problem is the chemical properties of carbon dioxide. It extinguishes the fire by displacing oxygen and cooling the combustion zone to −78°C. But there are materials that, when in contact with CO₂, react to release toxic gases, explode, or continue to burn in an oxygen-free environment. For example, alkali metals (lithium, sodium) ignite even more strongly when exposed to carbon dioxide, and some organic compounds decompose to form phosgene, a chemical warfare agent.

In this article we will analyze 5 fire categories, where a carbon dioxide fire extinguisher will lead to tragedy, and we will tell you what extinguishing agents to use instead. The information is critical for car owners (where OCs are often stored in the trunk), workshops and garages with chemical reagents.

1. Alkali and alkaline earth metals: why CO₂ will increase fire

Lithium, sodium, potassium, magnesium and their alloys - these metals are actively used in electric vehicle batteries (Li-ion, LiPo), pyrotechnics and some industrial processes. When burned, they react with carbon dioxide according to the formula:

4Na + 3CO₂ → 2Na₂CO₃ + C (carbon)
2Mg + CO₂ → 2MgO + C

As a result, it stands out pure carbon (soot), which heats up to +2000°C and supports combustion, and also produces caustic carbonates. For example, when extinguishing a lithium battery with a carbon dioxide fire extinguisher, the flame may increase 2–3 times due to thermal decomposition of CO₂.

• 🔋 Lithium-ion batteries (in power tools, laptops, electric cars)
• 🧪 Sodium (in laboratories, some types of lamps)
• 🔥 Magnesium alloys (in aviation, racing cars)
• 💥 Potassium (in pyrotechnics, fertilizers)

⚠️ Attention: If your electric vehicle battery catches fire (Tesla, Nissan Leaf), never use an op-amp - this will lead to thermal runaway (uncontrolled heating up to +1000°C). Instead use sand, special fire blankets or Class D dry powder extinguishers.

2. Organic nitrates and peroxides: risk of phosgene poisoning

Connections to groups –NO₂ (nitrates) and –O–O– (peroxides) are widely used in the paint industry, fuel additives and even in some auto chemicals (for example, carburetor cleaners). On contact with CO₂ they decompose, releasing:

• 💀 Phosgene (COCl₂) - a gas used as a chemical weapon in the First World War. 0.005% in the air is enough to be lethal.
• 🧪 Nitric acid (HNO₃) - Causes chemical burns to the lungs.
• 🔥 Self-igniting vapors - can ignite without a fire source.

Example: if a can of water caught fire in the garage nitro paint or benzoyl peroxide (used in body repair), carbon dioxide fire extinguisher converts fire into chemical attack. In such cases you need Class B dry powder fire extinguishers or foam compositions.

Substance	Where is it found?	How to extinguish instead of CO₂
Nitrofiber	Varnishes, paints, celluloid	ABC powder, water (fine stream)
Hydrogen peroxide	Bleach, rocket fuel	Foam, sand
Nitroglycerin	Explosives, drugs	Evacuation only + emergency call

3. Class A Combustible Solids: When CO₂ Is Useless

Carbon dioxide fire extinguishers not intended for extinguishing ordinary hard materials: wood, paper, fabric, rubber. Reason - low cooling capacity CO₂. The gas evaporates quickly, not having time to reduce the combustion temperature below the ignition point.

For example, if you try to extinguish the op-amp burning wooden shelf in the garage, the flame will go out for 5–10 seconds (due to the displacement of oxygen), but then resume with renewed vigor. Moreover, when extinguishing synthetic fabrics (e.g. car covers) CO₂ can contribute melting and release of toxic gases.

• 🌲 Wood, chipboard, plywood - require cooling with water or foam.
• 🧵 Fabrics, upholstery - extinguish with powder or water fire extinguishers.
• 🚗 Rubber (tires, seals) - use more efficiently BC powder.

⚠️ Attention: If the seat upholstery in a car catches fire, a carbon dioxide fire extinguisher will only will slow down fire, but will not put it out. Use Class A dry powder fire extinguisher or water (if there is no electrical wiring nearby).

4. Flammable liquids with a flash point below 0°C

Gasoline, acetone, alcohols and other flammable liquids (class B) can be extinguished with carbon dioxide, but only if their flash point is above 0°C. The fact is that CO₂ cools the combustion zone to −78°C, but if the liquid is already heated above its ignition temperature, it will evaporate and burn again.

Critical examples:

• ⛽ Ethers (flash point −45°C) - used in starting fluids for diesel engines.
• 🧴 Acetone (−20°C) - solvent for paints.
• 🔥 Carbon disulfide (−30°C) - in laboratories and viscose production.

In such cases, CO₂ is only splashes liquid, increasing the fire area. Work more efficiently:

• Foam (isolates the surface from oxygen).
• BC Powder (interrupts the combustion chain reaction).
• Special formulations (for example, "Trilon-B" for alkali metals).

Try covering the fire with a thick cloth (if the area is < 0.5 m²)|

Use a Class B dry powder fire extinguisher|

Do not direct the CO₂ stream at the surface of the liquid - only at the edge of the fireplace|

In case of large fires, evacuate and call the Ministry of Emergency Situations -->

5. High voltage electrical equipment (>1000 V)

Although carbon dioxide fire extinguishers are approved for extinguishing electrical installations up to 1000 V, at higher voltages (for example, in electric vehicle charging stations or industrial transformers) CO₂ becomes a current conductor. This is due to:

• 🔌 Gas ionization in an electric field.
• 💥 Risk of arc flash when the jet comes into contact with live parts.
• ⚡ Insulation damage due to sudden cooling.

For equipment over 1000 V use:

• Class E Powder Fire Extinguishers (for example, "PSB-4").
• SF6 gas (SF₆) - in industrial installations.
• Sand or fire blankets - for small fires.

What happens if you extinguish a 6000 V CO₂ transformer?

The carbon dioxide jet is ionized, creating conducting channel for electricity. This may lead to:

1) Short circuit with plasma release.

2) Fire extinguisher cylinder explosion due to overheating.

3) Electric shock man holding a fire extinguisher.

How to replace a carbon dioxide fire extinguisher: table of alternatives

If you store hazardous materials in your garage, workshop, or vehicle, replace or supplement the OC with other extinguishing agents. Below - optimal options for each case:

Fire type	Prohibited fire extinguisher	Recommended Replacement	Model example
Alkali metals (Li, Na, K)	OU, water, foam	Powder Class D	OP-4(D)
Nitrates, peroxides	OU, water	Powder ABC or foam	OP-5(ABC), OVP-5
Wood, fabrics (class A)	Op-amp	Water or foam	OV-5, OVP-10
Esters, carbon disulfide	Op-amp	Powder BC or foam	OP-4(BC)
Electrical equipment >1000 V	OU, water	Powder E or SF6 gas	OPS-6

✅ Electrical appliances up to 1000 V (computers, household appliances).

✅ Flammable liquids with a flash point >0°C (oils, diesel).

✅ Small fires of class B (gasoline, kerosene) - when used correctly (stream along the edge of the flame).-->

FAQ: Frequently asked questions about extinguishing with carbon dioxide fire extinguishers

Is it possible to extinguish a car battery with a carbon dioxide fire extinguisher?

❌ Noif this lithium-ion or lithium polymer battery (in hybrids, electric cars). CO₂ will increase combustion. For lead-acid batteries (regular starter) Op-amp is suitable, but more efficient powder class D.

Why can't you extinguish a person with carbon dioxide?

⚠️ The CO₂ jet has a temperature of −78°C and can cause frostbite of the skin and mucous membranes. In addition, there is a high risk carbon dioxide poisoning in a closed space (garage, car interior). To extinguish clothes, use fire extinguishing blankets or water.

What are the dangers of extinguishing CO₂ plastic?

🔥 Most plastics (polyethylene, polypropylene) release toxic gases (cyanide, chlorine). Carbon dioxide does not cool the material sufficiently, and after extinguishing the plastic may smolder and spontaneously combust. Use Class A powder fire extinguishers.

Is it possible to use an op-amp to extinguish gas (methane, propane)?

⚠️ Technically you can, but only if gas source is blocked. CO₂ does not completely extinguish a gas flame; it only extinguishes it temporarily. If there is a gas leak, the fire will restart. Optimal: close the valve + use a powder fire extinguisher.

How often should you check the carbon dioxide fire extinguisher in your car?

📅 According to GOST R 51057-2001, the OS check is carried out:

• 1 time per quarter — external inspection (integrity, pressure gauge).
• 1 time per 5 years - recharge.

There must be a fire extinguisher in the car secured in an accessible place (not in the trunk!) and have a valid seal.