Published: · Reviewed by Koray Korkut, Fire Department Director
Cooking fires are the number one cause of home fires in the United States. And the most common cooking fire call we respond to is a grease fire on the stove — almost always because someone panicked and did exactly the wrong thing. I have been on these calls. The kitchen goes from a pan fire that could have been smothered with a lid in five seconds to a fully involved kitchen because someone's instinct was to grab water. This piece explains what actually happens inside a grease fire, what you should do in the first ten seconds, and what will make it dramatically worse.
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Why You Must NEVER Put Water on a Grease Fire
Water on a grease fire does not extinguish it. It causes an explosion. Here is the physics of why, because understanding it makes it impossible to forget.
Cooking oil on fire is burning at around 600°F (315°C). Water boils at 212°F (100°C). When water hits oil at 600°F, it does not mix with the oil — it instantly vaporizes. That vaporization is the problem. Water expands approximately 1,700 times in volume when it turns to steam. In a fraction of a second, a small amount of water turns into a large amount of steam, and that steam expansion happens underneath and throughout the burning oil. The steam blast propels burning oil droplets in every direction — upward, outward, onto nearby surfaces, onto you. What was a pan fire becomes a fireball in the space of a heartbeat.
This is not a theoretical risk. It happens every single time. Even a small amount of water — a splash from a wet spoon, condensation from a frozen item — can cause a significant flare-up on a burning grease pan. The rule is absolute: no water, ever, on a burning grease fire.
Never put water on a grease fire. Never put a wet towel on a grease fire. Never put a frozen item into a burning pan. Never spray water from a distance thinking it will cool the oil. All of these cause the same steam explosion with the same result.
What To Do — Step by Step
You have seconds before a pan fire grows beyond what one person can handle. Here is the correct sequence, in order.
If you can safely reach the burner knob without putting your arm over the fire — turn it off. Removing the heat source is the most important first action. Do not skip this to grab a lid or an extinguisher first. No heat means the oil stops getting hotter and the fire becomes easier to control.
A tight-fitting metal lid cuts off the oxygen supply to the fire. Approach from the side, slide the lid horizontally over the pan, and set it down. Do not drop it from above — the impact can splash burning oil. Do not use a glass lid — extreme heat can shatter glass. Once the lid is on, leave it. Do not lift it to check. The fire needs the lid to stay on until the pan cools.
Baking soda (sodium bicarbonate) releases CO2 when heated and can smother a small grease fire. It takes a significant amount — not a pinch, but essentially dumping the entire box. A large cookie sheet or baking tray slid over the pan works the same way as a lid. Do not use flour (it is flammable and explodes similarly to water), baking powder, or any other powder you are not certain is baking soda.
Moving a burning pan of grease is one of the most common ways people get seriously burned and spread the fire. The oil sloshes, the fire follows, burning oil hits the floor or adjacent surfaces. Leave the pan exactly where it is. The stove is a contained area. The floor, the cabinet, and the wall are not.
If the fire does not go out within 10-15 seconds of the lid going on, or if it spread beyond the pan before you could cover it — get out. Close the kitchen door behind you to slow the fire's spread. Alert others in the home. Call 911 from outside. Do not go back in.
✓ DO
- Turn off the burner first
- Slide a metal lid over the pan from the side
- Use baking soda if no lid is available
- Use a Class K or ABC extinguisher if trained
- Get out and call 911 if it spreads
- Close the kitchen door when you leave
- Stay low if there is smoke
✗ DO NOT
- Put water on it — ever
- Use a wet cloth or towel
- Put a frozen item in the pan
- Move the burning pan
- Use flour or baking powder
- Use a glass lid
- Open the oven if the fire is inside it
- Re-enter after evacuating
Which Fire Extinguisher Works on a Grease Fire
Not all fire extinguishers work the same way on grease fires, and using the wrong type can make things worse.
| Extinguisher Type | Works on Grease? | Why / Why Not |
|---|---|---|
| Class K (wet chemical) | ✅ Yes — best option | Wet chemical agent reacts with hot oil (saponification) to form a soapy blanket that seals the fuel surface and prevents re-ignition. Designed specifically for cooking fires. |
| ABC dry chemical | ⚠️ Works but with risks | Can knock down the fire but the pressure blast can also splash burning oil and spread the fire. The powder makes a mess and does not prevent re-ignition as reliably. Better than nothing, worse than Class K. |
| CO2 extinguisher | ⚠️ Partial — use carefully | Can displace oxygen and knock down flames but the high-pressure discharge can scatter burning oil. Does not cool the oil — re-ignition risk is high once the CO2 disperses. |
| Water extinguisher | ❌ No — dangerous | Same explosion risk as pouring water. Never use a water extinguisher on a grease fire. |
| Halon / clean agent | ⚠️ Limited | Works on the fire but does not cool the oil. Re-ignition risk without continued application. |
If you have a kitchen, buy a Class K extinguisher and mount it on the wall near the exit — not next to the stove. You want to be able to reach it without walking toward the fire. A typical residential Class K extinguisher costs $30–50. That is cheap compared to a kitchen fire.
How to use an extinguisher on a grease fire: Stand back 6-8 feet. Use the PASS technique — Pull the pin, Aim at the base of the fire (not the flames), Squeeze the handle, Sweep side to side. With a Class K extinguisher, apply the agent in a gentle sweeping motion — you do not want to blast the oil the way a high-pressure dry chemical extinguisher might. After the fire appears out, watch for re-ignition for at least 15 minutes before turning away.
