Q: Will hand sanitizer explode in a hot car?
A: Probably not, but it is possible.
“Sanitizer does have alcohol in it and if exposed to heat, it could have the potential to ignite depending on the alcohol concentration.” said Victoria Fire Chief Tracy Fox. “The higher the concentration of alcohol, the more combustible.”
Any liquids propensity to burn is based on its flash point, which is the temperature at which the liquid gives off enough vapor to ignite in air.
Alcohol-based hand rubs tend to have a flash point in the 60-70 degree F. range, according to a public service announcement from the National Fire Protection Association Journal.
“Consequently, that puts them essentially right at room temperature, which means they don’t need any external heat source to cause them to actually give off those vapors,” said Guy Colona, NFPA’s assistant vice president of chemical engineering. “Once those vapors concentrate in those right proportions of fuel vapors with the oxygen in the air, then the only thing missing in order to make them ignitable is a viable ignition source.”
On a hot summer day, sun magnification of light through the clear plastic of a hand sanitizer bottle could technically cause combustion, but it is unlikely.
Storing hand sanitizer in large quantities does, however, pose a fairly significant fire risk.
During the COVID-19 pandemic, some people are stockpiling more hand sanitizer than usual. You have to have more than 5 gallons of hand sanitizer for the liquids to fall under the requirements of the NFPA 30: Flammable and Combustible Liquids Code.
The code outlines protection measures, including placing them in a flammable liquids cabinet or in an area with an automatic fire sprinkler system.