Part of that effort was a self-described “blitz” that sent FDA officials into retail establishments to uncover illegal sales of e-cigarettes to minors. While that operation officially began April 6, Gottlieb said the agency has issued warning letters to 40 retail locations since March of this year. More than half of those were convenience stores, with five branded 7-Eleven, four Circle K, three Cumberland Farms and one Sheetz, according to an FDA document.

“Protecting our nation’s youth from the dangers of tobacco products is among the most important responsibilities of the [FDA]—and it’s an obligation I take personally,” Gottlieb said in a statement April 24. “We recognize that if the FDA is to end the tragic cycle of successive generations of nicotine and tobacco addiction, we must take every opportunity to disrupt that process where it starts: youth access to and use of tobacco products.”