Lawmakers are pushing the U.S. Food and Drug Administration to act quickly to ban flavored e-cigarettes to combat a surge in teen vaping. Meanwhile, research this week found that flavored e-cigs hooked teens on tobacco more than non-flavored varieties.

The Trump administration last month vowed to clear the market of unauthorized non-tobacco-flavored e-cigarettes but has yet to enact a ban. It’s unclear how quickly flavored e-cigs and vaping products will be pulled from stores once the ban is in place or how regulators will crack down on violators.

“Each day that flavors are on the market is another day for kids to pick up their first e-cigarette and start a lifetime of nicotine addiction,” wrote Rep. Raja Krishnamoorthi, chair of the House Committee on Oversight and Reform’s Subcommittee on Economic and Consumer Policy, in a letter urging the acting FDA chief to ban flavored vaping products.

Krishnamoorthi said delaying the ban “jeopardizes the health of children.”

On Thursday, the U.S. Centers for Disease Control and Prevention released new numbers on vaping-related injuries showing that the number of injuries has soared to 1,604, and 34 people have died. 

A study published this week in the Journal of the American Medical Association found that flavored e-cigarettes acted as a gateway to future tobacco use among young and inexperienced users. Researchers found that 71.9% of teens who began using tobacco had first tried flavored e-cigs. In contrast, teens who tried non-flavored vaping products were less likely to become tobacco users.

The results aren't surprising. The latest National Youth Tobacco Survey showed the vast majority of youths favor fruit and menthol or mint flavors. Between 2017 and 2018, e-cigarette use surged 78% among high school students and 48% among middle school students.

Ahead of the FDA’s expected ban on flavored e-cigarettes, JUUL last week announced it would end sales of its non-tobacco, non-menthol-based flavors. JUUL is the e-cigarette market leader, accounting for 64% of e-cigarette sales in retail stores, as the Wall Street Journal reported. The company, which is under investigation by the FDA, the Federal Trade Commission and federal prosecutors in California, has been blamed for improperly marketing to teens and spurring the rise in underage vaping. 

Anti-tobacco organizations suggest JUUL will continue to target teens with its products. “JUUL deceptively claims it will only be selling menthol versions in the U.S. and never mentions that it has simply re-categorized the popular mint flavor as menthol,” said Matthew L. Myers, president for the Campaign for Tobacco-Free Kids, in a statement.

JUUL has agreed to stop selling the flavors mango, fruit, creme and cucumber, per its announcement.