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Parents hoping to pry the vapes from their teenagers’ hands now might face an even more uncertain road ahead. Just days after Food and Drug Administration Commissioner Scott Gottlieb reportedly delivered a plan to curtail e-cigarettes’ booming sales to the White House, he announced that he’ll be leaving his role as the head of the agency in April.

Gottlieb’s announcement was unexpected—he had publicly contradicted rumors of his departure as recently as two months ago—and it could be an inflection point for both anti-tobacco advocates and those who see e-cigarettes as an important harm-reduction tool in the fight against smoking. With rates of adolescent e-cigarette use continuing to soar, though, the biggest impact of Gottlieb’s sudden departure could be felt among teens themselves.

In Donald Trump’s administration, Gottlieb’s tenure as the head of the FDA has been something of an anomaly. Because of the commissioner’s professional history as a pharmaceutical consultant, industry watchdogs were initially concerned that he might spurn regulation and make the agency more business-friendly, as Trump’s appointees at the Environmental Protection Agency and Interior Department have done. Instead, Gottlieb has largely done the opposite: He’s been outspoken in his intent to regulate the availability of e-cigarettes, reduce tobacco levels in combustible cigarettes to nonaddictive levels, ameliorate the harms of the opioid epidemic, and lower consumer prices for prescription drugs.

Gottlieb’s measures against teen vaping are some of the FDA’s most high-profile moves since he joined in May 2017. On the heels of recent research indicating that almost 40 percent of American high-school seniors vaped that year, the agency proposed guidelines that would take flavored e-cigarette cartridges out of most brick-and-mortar retailers in America, including convenience stores. Flavored vape products, the agency argued, were especially easy entry points for teen use, and they weren’t necessary in order for e-cigarettes to be used as effective alternatives to combustible cigarettes for adult smokers.

That move was heralded as a step in the right direction by people such as Robert Jackler, a Stanford University professor who researches how e-cigarettes like the ultra-popular Juul are marketed to young people. Gottlieb’s plans to leave the agency worry him. “I hope that his successor shares a similar passion for protecting youth from nicotine addiction,” Jackler said in an emailed statement. “The upward spike in tobacco stocks is a worrisome sign that the industry anticipates relief from regulation.” Indeed, stocks for the tobacco giants Altria and British American Tobacco did inch northward after Gottlieb’s announcement yesterday, although no successor for Gottlieb’s role has been named.

Bonnie Halpern-Felsher, a pediatrics professor and tobacco-use researcher also at Stanford, feels similarly. “I am shocked and saddened by FDA Commissioner Gottlieb’s resignation,” she says. Although she emphasized that little is known about what’s to come at the agency, losing a strong advocate is always cause for concern. “I worry, since he has definitely been leading the way in proposing vaping regulation, recognizing and trying to reduce the youth-vaping epidemic,” Halpern-Felsher says.

Meanwhile, Gregory Conley, the president of the American Vaping Association, criticized Gottlieb’s lack of effort on behalf of small- and medium-size e-cigarette entrepreneurs. “We are hopeful that the next FDA Commissioner will undertake real efforts to repair our country’s broken nicotine regulatory system,” he said in a statement released on Twitter. Some conservatives have been critical of what they see as the current FDA’s overly meddlesome approach to vaping businesses, which they argue drives adult smokers away from alternatives that could save their life.

For Gottlieb’s part, he has continued to be outspoken, even after announcing his departure. In a live interview with The Hill on Facebook earlier today, he emphasized that his decision to leave the FDA was strictly out of a desire to spend more time with his family in Connecticut, and that he intended to put his last few weeks on the job to good use. “I am extremely confident that the policy that was reported on Friday will be out very shortly,” Gottlieb said, referring to rumors late last week that the FDA’s restriction on flavored vape cartridges had been turned over to the White House for final approval.

Gottlieb also said that he and the current administration hope to keep the current FDA team intact, which could help assuage fears that the agency’s perspective on regulation will change radically in the near future. That’s likely good news for those worried about the health of American adolescents: Little is known about what’s actually in vape liquid or what high nicotine concentrations, such as those in Juul cartridges, could mean for very young users’ future well-being.

Although the FDA now takes a strong position on adolescent use of e-cigarettes, among anti-tobacco advocates, the agency has been criticized for being slow to address the growing problem of teen vaping. Juul is by far the most popular vape product among young Americans, and since it came to market in mid-2015, its broad availability has caused a regulatory headache for those trying to curb its appeal. For most of its existence, kids could buy Juuls and their replaceable pods relatively easily from convenience stores and vape shops with lax ID practices, from online retailers, and—maybe most troublingly—from enterprising older classmates who sell them in schools. That broad and relatively easy access, coupled with Juul’s small, easily concealable size, has led millions of kids (many of whom don’t even realize it contains nicotine) into at least casual tobacco use.

Gottlieb also said in his interview with The Hill that he’s optimistic about the conversations he’s had so far about who will take on his position, and that e-cigarettes are an issue that person won’t be able to ignore. “You do not want kids initiating on these,” he says. “If we start seeing tobacco use rates in this country of 40 to 45 percent, and we start seeing combustible use go back up, I think you’re going to have a groundswell of people who are going to demand action.”

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