Two attendees compete in the biggest vape cloud competition at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. According to new research provided to Reuters, youngsters say that performing tricks is one of the top two reasons they began using e-cigs. (Photo by David Becker/Reuters)

Miraj Patel of Florida, blows vapor inside a bubble at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Miraj Patel of Florida, blows a bubble of vapor at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Angel Huezo, right, creates jellyfish-like figurines as he exhales at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Monique Agra samples flavored vape juices at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

T-shirts on display at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. New research provided to Reuters has found that performing tricks is one of the top two reasons young users say they consider the devices cool. (Photo by David Becker/Reuters)

Jerred Marsh (R) samples flavored vape juice from Nancy Reyes at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Attendees compete in the biggest vape cloud competition at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Bodie Hultz with Vape Affliction, uses a trash can to create rings of vapor at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Angel Huezo (L) blows a plume of vapor through a vapor ring created by Bodie Hultz at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Joe Rodriguez exhales a plume of vapor at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

An attendee adds vape juice to his electronic cigarette at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. (Photo by David Becker/Reuters)

Annie Young (L) and Dan Leano smoke e-cigs at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. According to new research provided to Reuters, youngsters say that the flavors of the vaping liquids, and the “ability to do tricks” are the top two reasons they consider electronic vaping devices cool. (Photo by David Becker/Reuters)