KATHARINE SEELYE

Fentanyl is a powerful synthetic painkiller that has been laced into heroin but is increasingly being sold by itself — often without the user’s knowledge. It is up to 50 times more powerful than heroin and up to 100 times more potent than morphine. A tiny bit can be fatal.

While heroin use has climbed among all demographic groups, it has skyrocketed among whites; nearly 90 percent of those who tried heroin for the first time in the last decade were white.