Embattled e-cigarette manufacturer Juul announced its CEO, Kevin Burns, left the company in an unexpected staff shakeup Wednesday morning. He will be replaced by K.C. Crosthwaite, an official at the tobacco giant Altria Group, which owns a 35% stake in Juul.

Crosthwaite oversaw Altria’s expansion into the business of creating smoking alternatives, including the vaping device IQOS from Philip Morris, approved by the Food and Drug Administration in April.