News that a Massachusetts man suffered severe burns while using a backyard grill — just after applying sunscreen spray — has raised new fears about sunscreen products. But dermatologists and burn experts called it a freak occurrence caused not by the sunscreen itself, but by the fact that the man was using an aerosol spray near an open flame.  Sunscreen itself is not usually flammable. But like hairsprays, spray deodorants, insecticides, paints and other products that can be sprayed out of a can or bottle, sunscreen can become flammable when used in aerosol form, said Dr. Darrell Rigel, a clinical professor of dermatology at New York University.  The man, Brett Sigworth, suffered severe burns on his chest, ear and back. He reportedly had just sprayed himself with layers of aerosolized Banana Boat sunscreen before walking over to his grill.  Dr. Rigel said that in over three decades of practicing, he had never seen or heard of a similar occurrence. But he called it plausible.  “Most of the sunscreen sprays have some kind of alcohol in them,” he said, “and the alcohol vapors are probably what caused the fire.”  Other chemicals that are used to make aerosols — things like volatile hydrocarbons, propane and dimethyl ether — are also flammable.  Because alcohol typically evaporates very quickly — within a minute or two — there is usually little risk of a fire hazard. But Dr. Rigel said it was likely Mr. Sigworth sprayed himself and then immediately got close to his grill. The bottle Mr. Sigworth used contains a warning label about flammability, similar to those found on hairspray and other aerosol products.  “He was most likely surrounded by alcohol vapors,” Dr. Rigel said. “If you do that with hairspray, the same thing would happen. I suspect even if you sprayed yourself and then lit up a cigarette right away, the match might be a trigger, or the red-hot cigarette might do it too.”  The company that makes the spray, Banana Boat, said it was unaware of any similar incidents but was taking the matter seriously. Mr. Sigworth, for his part, said he has no plans to sue, but wants people to be aware of the risk.  In recent years, the popularity of spray-on sunscreens has risen sharply. But should sunbathers worry this summer that a few spritzes of sunscreen might make them a walking fire hazard?  “People shouldn’t be worried that if they spray sunscreen on they’re going to explode,” Dr. Rigel said. Instead, take precautions, most importantly waiting two minutes after spraying sunscreen before getting anywhere near a grill or open flame, he said, which gives the alcohol enough time to evaporate.  Dr. Karthik Krishnamurthy, a dermatologist at the Montefiore Einstein Center for Cancer Care in New York, said that he and his colleagues had never heard of someone catching fire after applying sunscreen. But the risk of skin cancer is very real, he said, and outweighs any concerns about something that is essentially a rare occurrence.  “Sunscreen has been accused of a lot of things lately, but this has never been one of them,” he said. “The only real risk is with aerosolized spray cans, and it’s only when the spray is being discharged, just like with hairspray. I would encourage people to take it with a grain of salt.”
Sunscreens sprayed from a can, just like hairspray, paints and deodorants, are flammable in the seconds after they have been applied, experts say.