A gasoline fire requires a Class B fire extinguisher. Class B covers all flammable and combustible liquids, including gasoline, kerosene, oil, and grease. The most widely available option is a dry chemical extinguisher, which you’ll find at most hardware stores labeled as “ABC” (meaning it handles multiple fire classes) or “BC.” Both work on gasoline fires.
Why Class B Is the Right Rating
Fire extinguishers are classified by the type of fuel they’re designed to fight. Class A covers ordinary combustibles like wood and paper. Class B covers flammable liquids and gases. Class C covers electrical fires. Gasoline falls squarely into Class B, and using the wrong type of extinguisher on a liquid fuel fire can be ineffective or dangerous. A Class A water-based extinguisher, for example, can spread burning gasoline rather than put it out.
The number before the “B” on the label tells you the size of fire the extinguisher can handle. That rating is based on standardized tests using heptane, one of the main components of gasoline. A 10-B rated extinguisher, for instance, has been proven to extinguish a fire consisting of 31 gallons of heptane in a 25-square-foot steel pan. For a home garage or vehicle, a 10-B or 20-B rating is typically sufficient. Larger workshops or fuel storage areas call for higher ratings.
Dry Chemical vs. CO2 Extinguishers
Two main types of extinguishers carry a Class B rating: dry chemical and carbon dioxide (CO2). They work differently, and each has trade-offs worth knowing about.
Dry chemical extinguishers are the most common and the most practical for home use. They discharge a fine powder that coats the fuel, separating it from oxygen while also interrupting the chemical chain reaction that sustains combustion. This makes them highly effective at knocking down a gasoline fire quickly. The main downside is residue. The powder left behind is corrosive, especially to metal surfaces, and needs to be cleaned up promptly. Multipurpose (ABC) dry chemical extinguishers use a compound that also softens and sticks to hot surfaces, giving it an advantage if the fire has spread to nearby materials like wood or fabric.
CO2 extinguishers work by displacing oxygen around the fire with a cloud of gas and snow. Their big advantage is that they leave zero residue, which matters in environments with sensitive equipment like server rooms or workshops with electronics. The disadvantage is limited range: CO2 only reaches about 3 to 8 feet from the nozzle, meaning you need to get closer to the fire. Wind or strong air currents can blow the gas cloud away before it does its job, making CO2 a poor choice for outdoor use. For a gasoline spill in a driveway or near a vehicle, a dry chemical extinguisher is the better pick.
What to Look for When Buying
For most people, an ABC-rated dry chemical extinguisher is the smartest all-purpose choice. It handles gasoline (Class B), wood and paper (Class A), and electrical fires (Class C) in a single unit. Look for at least a 2-A:10-B:C rating on the label. This is the standard size sold for home and garage use, typically in a 5-pound canister.
If you keep gasoline cans in a garage, work on vehicles, or store fuel for lawn equipment, consider mounting a dedicated extinguisher within reach of those areas. Gasoline fires grow fast, and the seconds it takes to run to another room can make the difference between a manageable fire and one that’s out of control.
How to Use It: The PASS Method
Every portable fire extinguisher works the same way, following four steps known as PASS:
- Pull the pin. A small pin near the handle prevents accidental discharge. Yank it out.
- Aim the nozzle low, at the base of the fire. Spraying into the flames above the fuel does nothing. The goal is to cut off the burning liquid from its oxygen supply at the surface.
- Squeeze the handle slowly and evenly. A controlled discharge is more effective than emptying the canister in a burst.
- Sweep the nozzle side to side across the base of the fire, covering the full width of the burning area.
With a gasoline fire specifically, aim at the leading edge of the flames and sweep backward across the pool of fuel. Stand far enough back that the heat is tolerable but close enough for the agent to reach. Most dry chemical extinguishers have an effective range of 10 to 20 feet.
What Not to Use on a Gasoline Fire
Water is the biggest mistake. Gasoline floats on water, so pouring water on a gasoline fire spreads the burning fuel across a wider area. This can turn a small, contained fire into something much more dangerous in seconds.
Class A extinguishers that use pressurized water pose the same risk. Class D extinguishers, designed for combustible metals, are also ineffective on liquid fuel fires. If you’re unsure what type you have, check the label: the classes are clearly printed on every extinguisher, often with color-coded geometric symbols. Class B is marked with a red square.
Cleaning Up After Discharge
If you use a dry chemical extinguisher, the corrosive powder residue needs to be cleaned up quickly, especially from metal surfaces like engine parts, tools, or vehicle bodies. Start by vacuuming or sweeping loose powder. For residue that’s stuck on, spray a 50/50 mix of isopropyl alcohol and warm water, let it sit for several minutes, then wipe it away with a damp cloth. Finish with a soap-and-water wash and dry the area thoroughly.
The neutralizing step depends on the specific chemical agent. For sodium bicarbonate or potassium bicarbonate residue, a solution of hot water with a small amount of vinegar does the job. For mono ammonium phosphate residue (common in ABC extinguishers), a paste of baking soda and hot water works instead. In either case, wipe down with a damp rag after a few minutes, then do a final soap-and-water rinse. The faster you clean, the less risk of corrosion damage to metal surfaces.