A vape pen startup that's been taking over America made a splash last week with news that it was raising $1.2 billion for an overseas expansion. The company, Juul Labs, is moving quickly toward that goal, having closed on $650 million of its new funding round. The financing would value the company at $15 billion. Still, concerns about the startup's leading product — a trendy, high-nicotine vape pen known as a Juul — worry scientists and public health researchers. A vape pen startup that's taking over America is speeding toward its ambitious goal of raising $1.2 billion.