Summer Safety Tips for Hand Sanitizer


A person presses a hand sanitizer pump
With summer temperatures reaching 100 degrees or higher, Dr. Mihaela Stefan, professor of chemistry and biochemistry and of bioengineering at The University of Texas at Dallas, said hand sanitizer bottles should not be left in hot cars.
Alcohol, the active ingredient in hand sanitizers, evaporates quickly in air, and as it does so, the concentration of alcohol in the product decreases.
“After hand sanitizer has been in a hot vehicle for some time, the sanitizer could lose its effectiveness and, in very extreme situations, could be dangerous,” she said. “As the concentration of alcohol decreases, so does the sanitizer’s efficiency in killing germs.”
Stefan, who is the Eugene McDermott Professor in the School of Natural Sciences and Mathematics, said that while conditions vary, it could take two weeks or longer before the alcohol level is reduced. Even then, she said, using more sanitizer than usual could still be lethal to germs.
“Even though a sanitizer with slightly reduced alcohol content can still work if you use enough, you’re still better off using sanitizers with 60% to 70% alcohol content that has not been exposed to the heat,” she said.
Stefan has several safety tips about hand sanitizer:

  • During the heat of summer, do not leave hand-sanitizer bottles in the car. Exposure to high temperatures could make them less effective.
  • Keep your hand sanitizers nearby, preferably at room temperature.
  • Watch out for supposed hand sanitizers that have little or no alcohol content. Such sanitizers will not be effective against COVID-19.
  • Use hand sanitizer from reputable manufacturers. The Food and Drug Administration has issued warnings about so-called sanitizers that are not safe.
  • There is the possibility that alcohol-based hand sanitizers, when in a hot car, could cause a build-up of alcohol vapors. Although very unlikely, if there is static electricity or a flame from a cigarette lighter, alcohol vapors could be ignited.
  • Use hand sanitizer even when your hands are not visibly dirty. After using it, don’t wipe off the excess; let your hands air dry.
  • The best way to kill germs is through the regular use of soap and water.

–Phil Roth