A recent study published in the latest edition of the medical journal Pediatrics has found that more than a quarter of all high school students who are using e-cigarettes are taking the habit a step further. The practice is known as “dripping,” by which the liquids used for vaping are literally dripped directly on to hot surfaces (such as steam radiators and electric stove burners). The reason: “dripping” produces heavier vapors, more intense flavors and increases the effects of the product.

The study involved over 7,000 high school students from across the state of Connecticut. Of those, nearly 1,100 were regular “vapers.” 26% of e-cigarette users – primarily white males – reported using e-cigarettes for the purpose of dripping.

While this is the first time that dripping has been actively studied using scientific methods, the practice has been around for a few years, according to blog entries among the e-cigarette user community and online groups. However, it is not known if the number of e-cigarette users who engage in dripping is on the rise or has remained consistent.

It could very well be more hazardous to one’s health than normal e-cigarette smoking.  Another study, published last year in Nicotine and Tobacco Research, found that dripping produced greater amounts of “volatile aldehyde emissions” (i.e., formaldehyde, a substance used in embalming fluid) than with the conventional use of e-cigarettes – or even regular tobacco cigarettes. Volatile organic compounds (VOCs) – including aldehyde emissions – are a common product of cooking oils that are overheated. Regular exposure to VOCs can have harmful effects on the respiratory system, reducing lung function and may even increase the risk of lung cancer.

Although there are still questions about the short and long-term effects of “vaping,” it is known that many of the chemicals used to make e-liquids – such as propylene glycol and glycerin – can produce toxic and even carcinogenic gases when heated to high temperature levels. Those e-liquids also contain artificial flavorings, and while these may be considered “non-toxic” when ingested normally, very little is known about what happens to the respiratory system when these vapors are inhaled on a regular basis – particularly at elevated temperatures.

Dr. Suchitra Krishnan-Sarin, a professor of psychiatry at the Yale University School of Medicine, recommends that parents should strongly discourage their children from using e-cigarettes altogether. Despite laws across the country prohibiting the sale of e-cigarettes and vaping products to minors, many young people skirt the law by ordering online. Parents should be especially vigilant when it comes to dripping if their teenage children are already using e-cigarettes and warn them about the possible health dangers.