E-cigarettes are trendy among high school students and young adults, and the research overwhelmingly indicates that they're probably healthier than traditional cigarettes (in part because they produce far fewer toxic, cancer-causing chemicals). What's not to love, right?

But while vaping in itself may be safer overall than smoking "combustible" cigarettes, there's one unlikely side effect you probably hadn't thought of—and it could result in an unexpected (and painful) hospital visit.

University of Arizona trauma surgeons have noticed a rise in the number of burn injuries as a result of lithium-ion battery failure in e-cigarettes and vapes. Their research, which investigates the surprising safety hazard of the battery-powered alternative to tobacco products, can be found in a new study published in the May 2017 issue of the journal Burns.

About a year and a half ago, Dr. Gary Vercruysse, a burn surgeon at the Banner–University Medical Center in Tucson, treated a 58-year-old man with nasty burns on his left thigh. Weeks later, Vercruysse saw a similar burn injury, and then another, prompting him to figure out why all of these patients had such similar cases. "They all told me basically the same thing: They had an electronic cigarette in their pocket, then they started feeling a lot of heat in their pocket and then they couldn't get their pants off or get the device out of their pocket quickly enough," Vercruysse wrote in a press release from the university published on EurekAlert.

But why do e-cigs overheat, and sometimes even ignite, in the first place? It all comes down to what the study describes as "thermal runaway," which happens when the battery becomes damaged, causing its internal temperature to rise uncontrollably and even combust.  

"I think in general the public thinks that e-cigarettes are somehow better for you than tobacco cigarettes," says Dr. Vercruyssel. "But they still deliver nicotine, which isn't good for you, and this particular product has a defect where the battery can malfunction." So instead of continuing to vape, which has been shown to actually decrease your chances of quitting smoking, take a stab at dropping the habit altogether—research shows you'll be happier and richer as a result.