Using e-cigarettes, or vaping, is considered a healthier alternative to smoking tobacco, but credible evidence suggests that these battery-operated devices have harmful and unknown effects.

According to the American Lung Association, using flavored e-cigs can cause a rare, life-threatening and irreversible lung condition called bronchiolitis obliterans.

Also known as “popcorn lung,” the disorder causes inflammation in the smallest airways in the lungs that leads to scarring and narrowing of both the lung’s airways and tissues. Symptoms include a dry cough, wheezing, shortness of breath and unexplained fatigue that leads to difficulty breathing.

The word popcorn alludes to the organic chemical compound diacetyl, which was once commonly used to give foods, like popcorn, a buttery flavor. (Once popcorn makers learned of diacetyl’s dangerous effects, they ceased using it.)

Recent findings showed that 39 out of 51 flavored e-cigarettes tested contained diacetyl and that the chemical is found primarily in strongly flavored varieties, including vanilla, caramel and coconut.

Although popcorn lung is incurable, its symptoms can be managed or even reduced. But why court problems? Just avoid vaping altogether.