Aerosol hairspray is extremely flammable. The U.S. Consumer Product Safety Commission classifies products as “extremely flammable” when their flash point is at or below -6.7 °C (20 °F), and most aerosol hairsprays meet that threshold. The risk comes from both the propellants that push the spray out of the can and the solvents that carry the styling ingredients to your hair.
What Makes Hairspray So Flammable
Aerosol hairspray is essentially a cocktail of flammable chemicals under pressure. The propellants, which can make up a huge portion of the formula, are typically dimethyl ether or hydrocarbons. These gases are what create the fine mist when you press the nozzle, and they ignite easily. The solvent base is usually ethanol or isopropyl alcohol, sometimes making up 95% of the non-propellant liquid. Alcohol evaporates fast, which is why hairspray dries quickly on your hair, but it also means a cloud of flammable vapor surrounds you during application.
When you spray hairspray near any ignition source, the result can be dramatic. Regulatory testing actually measures this: a can is placed six inches from a candle flame, the valve is opened fully for 15 to 20 seconds, and testers measure how far the resulting flame jet extends. They also test with the valve partially open to check whether fire can travel back toward the nozzle. Most aerosol hairsprays produce a visible flame projection in these tests, which is why every can carries a flammability warning.
The Risk Doesn’t End When It Dries
Many people assume that once hairspray dries, the danger is over. That’s partly true for the alcohol, which evaporates within seconds. But the story is more complicated when you factor in overspray, the fine mist that lands on your clothes, countertops, and anything else nearby during application.
Research from Boise State University found that hairspray overspray on clothing significantly changes how fabric burns. Polyester exposed to hairspray saw maximum flame temperatures increase by 140%, with burn times rising by 74%. Nylon was even more affected: flame temperatures jumped 178%, and burn times increased 75%. Natural fibers like silk, cotton, and wool showed no change, likely because synthetic fabrics interact differently with the adhesive chemical layer that hairspray deposits on surfaces.
This matters in real-world settings. If you spray your hair and overspray settles on a polyester blouse, then you use a curling iron or stand near a gas stove, that fabric is meaningfully more flammable than it was before. Hair salons, where heated tools and hairspray are used constantly in close proximity, carry a particular risk for both stylists and clients.
Heat Tools and Open Flames
The most common real-world hazard is using hairspray near heat sources. Curling irons, flat irons, and blow dryers all reach temperatures high enough to ignite hairspray vapor or residue. The safest approach is to finish all heat styling before applying hairspray, and to let the spray fully dry before going near any heat source. Never spray hairspray while a curling iron or flat iron is in your hand or near your head.
Open flames are an obvious risk, but people underestimate how far an aerosol spray can carry. A lit candle across a bathroom counter, a gas stove burner in the next room, even a cigarette lighter can ignite the vapor cloud from a fresh spray. The mist travels farther than it looks, especially in enclosed spaces with little air circulation.
Storing Aerosol Cans Safely
The pressurized can itself is a hazard independent of the spray. Aerosol cans left in vehicles on hot days have ruptured violently. Direct sunlight through a car windshield can push interior temperatures well above what the can is designed to handle, and when the pressure inside exceeds the container’s limits, the can bursts. The flammable contents then become an additional fire risk in an already dangerous situation.
Store aerosol hairspray at room temperature, away from direct sunlight, radiators, and any heat-producing appliances. Never puncture or incinerate a can, even if it feels empty. Residual propellant inside can still ignite or cause the can to rupture.
Lower-Risk Alternatives
Pump-spray hairsprays eliminate the propellant issue entirely. Without pressurized gas, there’s no fine aerosol mist and no propellant to ignite. Pump sprays still contain alcohol as a solvent (typically ethanol or isopropanol making up 73 to 85% of the formula), so they’re not completely non-flammable during application. But they produce larger droplets that don’t hang in the air the way aerosol mist does, which significantly reduces the risk of a vapor cloud igniting.
Water-based styling products like mousses, gels, and creams avoid alcohol-based flammability altogether. If you regularly style near heat tools or work in a kitchen with gas burners, switching away from aerosol hairspray is the simplest way to reduce your fire risk. For anyone who prefers the fine, even coverage of an aerosol, the key precaution is timing: spray in a well-ventilated area, away from all heat and flame sources, and wait for it to dry completely before using any heated styling tool.