Fentanyl has long been one of the most dangerous wares of the underworld cryptocurrency economy—so dangerous, in fact, that even many dark-web markets have banned it. But new research shows that cryptocurrency is playing a different role in that deadly opioid’s supply chain: Chinese chemical producers are accepting cryptocurrency as payment for fentanyl ingredients they’re selling to drug operations that mass-produce the narcotic in countries around the world. And they’re offering it not on the dark web, but in full public view.