The e-cigarette industry in the United States is projected to gain over three-billion dollars in sales this year. E-cigarettes were originally marketed to adults as an aid to quit smoking. But the biggest users are teenagers. The US Food and Drug Administration says minors are picking up the habit at an alarming rate. And, as CGTN's Karina Huber reports, the FDA is now cracking down on e-cigarette makers.

The U.S. Food and Drug Administration recently released this graphic video. The video is part of a new public health campaign meant to scare teenagers away from the use of e-cigarettes, which the FDA says has reached epidemic proportions.

SCOTT GOTTLIEB COMMISSIONER, US FOOD & DRUG ADMINISTRATION "I use this word epidemic with great care. E-cigs have become an almost ubiquitous and dangerous trend among teens."

According to the U.S. Centers for Disease Control, e-cigarettes are the most used tobacco product among American teens. More than two million of them - or roughly eleven percent of high schoolers say they have vaped at least once in the last 30 days.

E-cigarettes were originally meant for adults looking for a safer alternative to smoking. Users inhale fewer toxic chemicals but e-cigs often contain higher levels of nicotine.

Health professionals are worried about the impact of nicotine on young growing brains. They are also concerned about the lack of information on other health risks.

DR. NORMAN H. EDELMAN SENIOR ADVISOR, AMERICAN LUNG ASSOCIATION "What the long-term effects are going to be - we don't know because they just haven't been around long enough. Remember it took decades to figure out that ordinary cigarettes cause lung cancer."

SCOTT GOTTLIEB COMMISSIONER, US FOOD & DRUG ADMINISTRATION "The FDA will not tolerate a whole generation of young people becoming addicted to nicotine as a trade-off for enabling adults to have unfettered access to these same products."

The dominant brand among teens is Juul, which has a vaping device that looks like a flash drive. It also sells flavored pods that critics say are meant to appeal to kids.

KARINA HUBER NEW YORK "The FDA recently seized documents related to Juul's marketing practices. It has warned it and other makers and sellers that if they can't keep e-cigarettes out of the hands of minors, some of their products may be pulled off the market."

Edelman thinks the best way to tackle the problem is for regulators to treat e-cigarettes like regular cigarettes.

DR. NORMAN H. EDELMAN SENIOR ADVISOR, AMERICAN LUNG ASSOCIATION "If we taxed e-cigarettes the way we tax ordinary cigarettes, there certainly would be a reduction in utilization of e-cigarettes and it works best in children, teenagers."

Karina Huber, CGTN, New York.