When it comes to vaping, some teens are too smart for their own good.

They’ve become experts at hiding their habit, yet are often ignorant about the long-term effects.

“We’re very concerned,” said Paige McGowan, program coordinator for the Tobacco, Vaping and Marijuana Prevention Program at the Spokane Regional Health District.

Noting that teenage brains are still developing, McGowan said “there’s not enough research and we don’t know the long-term effects.”

Marketed to adult smokers as a method to quit smoking, Juul and other brands contain varying amounts of nicotine.

Nicotine can affect learning, memory and attention in the teenage brain, but there’s little research on how e-cigarette vapor affects lungs, which do not fully mature until the 20s.

They also contain flavorings such as diacetyl, a chemical linked to lung disease; cancer-causing chemicals such as formaldehyde; and heavy metals such tin, nickel and lead.

The amount of nicotine ingested depends on the product. For example, data published by Juul Labs indicates that in its standard five percent nicotine strength pods, 10 puffs are equivalent to one cigarette.

However, e-cigarette vapor lacks the harshness of traditional cigarettes, which makes it easier to pick up the habit.