You have probably seen e-cigarettes showing up more frequently, but how can you be sure everybody is actually just vaporizing nicotine? According to a report from USA Today, a new study has shown that high school students are increasingly using handheld vaporizers, or e-cigarettes, to inhale marijuana at a steadily increasing rate.

The study found that roughly 27 percent of high school students have reported using an e-cigarette to smoke marijuana. The students most likely to use the device to inhale cannabis were male and on the younger end of the spectrum.

E-cigarettes are widely advertised as an alternative to traditional cigarettes, and contain a heating element that vaporizes solutions that contain nicotine. Now, as more people adopt their use, teens are figuring out that it’s relatively easy to switch out the nicotine with marijuana and smoke out in the open.

Vaporized marijuana lacks the characteristic scent of the plant when burned, and researchers believe that it is much easier to conceal pot use with the devices.

The survey, carried out by researchers from Yale, questioned nearly 4,000 Connecticut students. The results were published in the Monday issue of Pediatrics.

The study is the first of its kind, and did not examine any of the health implications of using e-cigarettes to vaporize marijuana. Many studies have shown that pot use can be damaging to the developing brain, in addition to studies that have demonstrated a sharp uptick in e-cigarette use among teens in recent years.