The agency sent a warning letter to the company, saying it violated regulations by touting its vaping products as safer than traditional tobacco cigarettes.
Juul Labs, the dominant e-cigarette company, illegally marketed its vaping products as a less harmful alternative to traditional cigarettes, the Food and Drug Administration said on Monday, casting a deepening shadow over the safety of e-cigarette devices.
The agency issued a warning letter to Juul, saying that the company violated federal regulations because it had not received federal approval to promote and sell its vaping products as a healthier option.
The F.D.A.’s action dealt a setback to the company’s efforts to rebrand itself after public outrage erupted over a surge in teenage vaping.
And it served as a reminder that the health effects of e-cigarettes are not established at a time when more than 400 people have been sickened by vaping-related illnesses. Five deaths have been linked to vaping, and hundreds of people have been hospitalized. Public health investigators have yet to determine a specific cause, but they have cited the use of cannabis and nicotine vaping products as possibilities. No one product or company has been implicated.
The investigation into Juul’s practices preceded this summer’s spate of lung illnesses, and was prompted by concerns that the company’s marketing and sales practices targeted youths. It included a review of congressional testimony from Juul executives, consumers — students and parents — and antismoking activists.