Fentanyl Is Creeping Into the Mainstream Drug Supply

None of the nine wealthy 20-somethings who were rushed to Manhattan emergency rooms by ambulance one night in November 2019 meant to use opioids. They all thought they were using cocaine, until seven of them passed out within minutes of the first bump.

All of them needed hits of naloxone, the overdose reversal drug, on the way to the hospital. Two were so far gone that they needed three.

The partiers were part of five groups who didn’t know each other, but several had the same contact’s number in their...