text: Cigarette-smoking teenagers hit a new low last year as youngsters turn to e-cigarettes instead, a study has revealed. Around two million high school students admitted to buying vaporizers in 2014 - more than triple the 660,000 recorded the year before. But smoking of traditional cigarettes plummeted to about nine per cent. On the rise: Around two million high school students now admit to buying e-cigarettes . The CDC report, released on Thursday, is based on a national survey of about 22,000 students at middle schools and high schools, both public and private. Tom Frieden, CDC director, remarked that the results are 'alarming' and 'shocking'. 'What's most surprising is how in­cred­ibly rapid the use of products other than cigarettes has increased,' Frieden said in an interview quoted by The Washington Post. 'It is subjecting another generation of our children to an addictive substance.' E-cigarettes typically deliver nicotine, propylene glycol, glycerin and flavorings through inhaled vapor. They have been on sale in the United States since 2006, but this is the first year that the Centers for Disease Control has measured their use. It follows a government-funded study released in December which found similar trends, leading experts to warn of a potential 'epidemic of teen tobacco use'. 'The concern is that e-cigarette advertising is recruiting intermediate risk adolescents to nicotine use- kids who would not otherwise have started smoking,' said James Sargent, of Dartmouth Hitchcock's Norris Cotton Cancer Center in a paper published  in the journal Pediatrics. There are currently more than 400 brands of 'e-cigs' available. E-cigs contain far fewer cancer-causing and other toxic substances than cigarettes, however their long-term effects on health and nicotine dependence are unknown. The popularity of e-cigarettes, which typically deliver nicotine, propylene glycol, glycerin and flavorings through inhaled vapor, has increased in the past five years. 'These are kids who might go on to smoke cigarettes, which are much better at delivering nicotine than e-cigarettes. 'If this pattern of use is adopted by adolescents in the continental U.S., we could be in for an epidemic of teen tobacco use in this country that could greatly reduce the overall benefits to public health of e-cigarettes.' Researchers have been critical of the fact that packaging and marketing of e-cigarettes is not regulated, and that manufacturers' opportunities to target adolescents are wide open, absent FDA regulation of these products. There are currently more than 400 brands of 'e-cigs' available in the US. E-cigs contain far fewer cancer-causing and other toxic substances than cigarettes, however their long-term effects on health and nicotine dependence are unknown. The CDC study also revealed that about nine per cent of teenagers surveyed said they had tried hookahs.
target: Two million high school students admitted to using e-cigarettes in 2014 .
  That is an increase of 13 per cent from the 660,000 recorded in 2013 .
  Traditional cigarette use has plummeted by 9 per cent, CDC study shows .
  Experts warn e-cigarette marketing is not regulated .