The fruity flavors of and odorless smoke emitted by e-cigarettes are not as harmless as users believe. The 10 million adults and teenagers who vape regularly in the U.S. are exposing themselves to various levels of toxic chemicals, according to a new study  by researchers at the University of North Carolina School of Medicine, prompting the U.S. Food and Drug Administration (FDA) to look into regulating the ingredients and flavors in tobacco products, including e-cigarettes.
“While we don’t know exactly what levels of toxins these devices are creating, many of the ingredients in e-cigarettes, when heated and inhaled, create dangerous levels like those found in class-one carcinogens,” said Michael Hernandez, M.D. , a pulmonologist with the Lung Health  Program at South Miami Hospital. “These type of carcinogens cause respiratory illnesses, damage to the lungs and in some cases, cancer. There’s certainly a concern with long-term usage.”
The liquid inside e-cigarettes contains varying high levels of toxic metals, a study led by researchers at Johns Hopkins Bloomberg School of Public Health found. The five types of metals, mainly – cadium, chromium, lead, manganese and nickel – stem from the coil that heats the liquid and turns it into vapor. In aerosol form, these metals can cause serious health conditions, such as neurotoxicity, cardiovascular disease, respiratory disease and lung cancer, researchers say.
One recent research study  by the National Institute of Environmental Health Sciences found the amount of lead in e-liquid is 25 times higher after it’s heated through an e-cigarette.
Vaping Popular With Teens and Adolescents
More than 2 million middle- and high-school students currently use e-cigarettes, according to data from the National Youth Tobacco Survey, released in 2016 by the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). While young people’s use of e-cigarettes exceeds the their use of cigarettes and other tobacco products, vaping is also leading more youth to transition to smoking cigarettes.
In one recent survey, 168,000 adolescents who had never smoked before said they became addicted to e-cigarettes after their first try vaping, Dr. Hernandez says. Another study showed high school students who used e-cigarettes in the last 30 days were seven times more likely to smoke cigarettes six months later, notes the National Institute on Drug Abuse.
“What we do know from the limited data collected so far is that vaping leads to more smoking of regular cigarettes, especially in adolescents,” said Dr. Hernandez, who also leads smoking cessation programs  at South Miami Hospital. “The fruity flavors of e-cigarettes have created a new group of young people addicted to nicotine, and vaping has become a gateway to smoking.”
More than 80 percent of middle- and high-school students who use e-cigarettes said they use them “because they come in flavors I like,” according to a study published in the Journal of the American Medical Association.
The way kids are consuming e-cigarettes could also be increasing the amount of harmful chemicals they are inhaling. A newer device that looks like a USB flash drive, called the “Juul,” is deceiving parents and teachers alike. It’s small and discreet and even charges like a USB in a laptop or other USB port. A big draw for young people is the flavor of the “juice,” or liquid, that fuels the Juul. Mango, cool mint and fruit medley are some of the available flavors enticing to kids.
Despite the devices’ small size, “juuling” delivers a powerful punch. One pod of liquid, which yields about 200 puffs, contains as much nicotine as a pack of cigarettes. The nicotine concentration is about 59 mg/mL, which is more than double that of other vaping products.
“Manufacturers’ claims that e-cigarettes are ‘cleaner’ than cigarettes may possibly hold some truth, but they have other things that are dangerous,” Dr. Hernandez said. “The problem is there’s no long-term health data about e-cigarette use. We really don’t know what levels of carcinogens and metallic these devices are delivering.”