E-Cigarette Use Among Teens Tripled in 2014

The number of American teens puffing on e-cigarettes tripled in 2014, making them the most popular tobacco product for high schoolers, data from the Centers for Disease Control show. At the same time, the rate of teens smoking conventional cigarettes declined. Here's the chart, based on data from the National Youth Tobacco Survey:

The CDC estimates that about 2 million high school students use e-cigarettes in the U.S. The devices are also the most prevalent form of tobacco used by middle schoolers. Researchers are still probing the long-term consequences of vaping, which is widely believed to be safer than inhaling tobacco smoke. A paper in the journal Tobacco Control suggests that chemicals in nicotine liquid that are considered safe to eat may be harmful when inhaled into the lungs.