Employees at Juul Labs got some awkward news last week: no more vaping in the office.

Juul is a hot and richly-valued startup that sells e-cigarettes. Spun out of Pax Labs in July 2017, Juul shot to success with sleek devices and fruit-flavored nicotine pods. Juul raised money at a $15 billion valuation over the summer and is reportedly nearing a $12.8 billion deal (subscription) with Marlboro maker Altria Group that would put Juul’s value at $38 billion. That would leapfrog the valuation of private technology company Airbnb, which last raised money at a mark of $31 billion.

The e-cig company’s products have hooked teens and alarmed US regulators. A recent survey found the number of high school seniors who reported vaping nicotine in the past 30 days has nearly doubled in the course of a single year, to 21% in 2018 from 11% in 2017. The survey specifically called out Juul for its rapid spread among adolescents.

But back to the office rules.

On Dec. 11, Juul chief executive Kevin Burns emailed US employees to let them know they could no longer use Juul products at work, effective immediately, the Wall Street Journal reported (subscription). Burns said the San Francisco-based company had received an inquiry from the city about vaping in its office. Using e-cigarettes in California workplaces has been illegal since June 2016.

“It may feel nonsensical to prohibit at-work use of the very products we work hard to create and promote,” Burns wrote in the email. “But the bottom line is we need to comply with legal requirements the same as any company.”

Juul has about 1,500 employees, according to the Journal. Those in San Francisco were invited to take their vaping outside to a tent, which is being constructed specifically for that purpose. Juul also has offices in cities including Chicago, Dallas, Los Angeles, and New York. The new rule bans vaping in all US locations except for spaces Juul rents in four unspecified states, the Journal reported.

“[R]est assured that we are committed to exploring options for team members who desire to vape while at work,” Burns said in the email.