Water is the most dangerous thing you can put on a grease fire. When water hits burning oil, it instantly vaporizes and expands to roughly 1,700 times its original volume, launching flaming oil in every direction. But water isn’t the only kitchen item that will make a grease fire worse. Several things that seem like they’d help, including common fire extinguishers, can turn a small stovetop flame into a kitchen-wide disaster.
Why Water Causes an Explosion
Cooking oil burns at temperatures well above water’s boiling point. When even a small amount of water contacts that superheated oil, it doesn’t slowly simmer. It flash-converts to steam, expanding to 1,600 to 1,700 times its liquid volume in an instant. That rapid expansion throws burning oil out of the pan and into the air as a fine mist, which ignites on contact with the flames. The result is a fireball that can reach the ceiling and spread to cabinets, walls, and curtains within seconds.
This is why you should never carry a burning pan to the sink. The instinct makes sense: sinks are where you put water on things. But the combination of sloshing hot oil (which can spill onto your hands and clothes) and the temptation to turn on the faucet makes this one of the most common ways small grease fires become serious burn injuries.
Wet Towels and Damp Cloths
A damp towel or cloth might seem like a reasonable substitute for a lid, but it introduces the same problem as pouring water directly. The moisture trapped in the fabric hits the burning oil and vaporizes, potentially splashing flaming grease out of the pan. Fire services in the UK have issued specific warnings against this after responding to kitchen fires caused by damp tea towels placed over burning oil. If a towel is completely dry, it could theoretically smother a very small flame, but the risk of it catching fire or containing hidden moisture makes it an unreliable choice.
Flour, Sugar, and Baking Powder
Flour is one of the most dangerous things you can throw on a grease fire. It’s made of complex carbohydrates, which are essentially sugar molecules. When flour particles become suspended in the air above a flame, they mix with oxygen and can detonate. This is the same mechanism behind flour mill explosions. Tossing a handful of flour at a burning pan creates exactly that scenario: a cloud of fine, flammable particles meeting an open flame.
Granulated sugar melts and caramelizes when it hits high heat, turning into a sticky, burning liquid that spreads the fire rather than putting it out. Powdered sugar is even worse. Its fine particles behave like flour, combusting or exploding when they contact the flames. Baking powder, despite containing some baking soda, also includes starch and other compounds that make it unreliable and potentially flammable in this situation.
Baking soda (pure sodium bicarbonate) is a different story. It releases carbon dioxide when heated, which can smother a small grease fire. But “small” is the key word. You need a large quantity to be effective, and if the fire has grown beyond the pan, baking soda won’t cut it. Salt works similarly in large amounts but has the same limitation. Neither should be your first choice over a lid.
The Wrong Fire Extinguisher
This one surprises most people. A standard household fire extinguisher can make a grease fire worse if it isn’t rated for cooking oil fires. Grease fires fall into a specific category called Class K (or Class F in some countries), and only extinguishers rated for that class are safe to use on them.
A CO2 extinguisher, for example, will cool the top layer of oil but won’t penetrate below the surface. The oil underneath retains enough heat to reignite once the CO2 dissipates. The force of the gas can also blow burning oil out of the pan, spreading the fire to new areas. Other common extinguisher types that use pressurized water are obviously dangerous for the same reasons water itself is dangerous.
Class K extinguishers work through a chemical reaction with the cooking oil. The discharge is acidic, and when it meets the basic (high pH) cooking grease, it creates a soapy film that sits on top of the oil and smothers the fire. This process, called saponification, is specifically designed for the temperatures and fuel type involved in kitchen grease fires. If you keep a fire extinguisher near your stove, check the label to confirm it covers Class K fires.
Never Move the Pan
Picking up a flaming pan and trying to carry it outside or to the sink is one of the most common causes of serious burn injuries in kitchen fires. Burning oil sloshes easily, and even a small stumble can send it onto your hands, arms, or the floor. Once flaming grease hits the ground, it spreads across the surface and is nearly impossible to control. The safest approach is to leave the pan exactly where it is.
What Actually Works
The single most effective tool for a stovetop grease fire is already in your kitchen: a lid. Slide a metal lid over the pan to cut off the fire’s oxygen supply, then turn off the burner. Don’t lift the lid to check. The oil inside stays dangerously hot for a long time, and exposing it to air can reignite the flame. Leave the lid in place until the pan has cooled completely.
If the fire has spread beyond the pan, or if you don’t have a lid that fits, don’t try to fight it. Get everyone out of the house, close the kitchen door behind you to slow the fire’s spread, and call emergency services from outside. Cooking fires grow fast. The National Fire Protection Association recommends that if there’s any doubt about whether you can safely contain the fire, your only job is to get out.
Keeping a lid within reach while you cook is the simplest precaution you can take. It costs nothing, requires no training, and handles the most common grease fire scenario in seconds.