If you weren’t looking, you’d miss it: a silver van the size of an ice cream truck parked at North and California and emblazoned with the words Chicago Recovery Alliance. Step inside, and you’ll find a whirl of activity: volunteers drawing blood for hepatitis C tests, hazmat bins being filled with used syringes, opiate users stocking up on needles, cookers, alcohol swabs, even bike inner tubes to tie off with. At the center of it all is CRA’s director, Dan Bigg. “Are you thinking about treatment? Have you overdosed since the last time you were here? Do you need naloxone?” he asks as he checks in a stick-thin Puerto Rican man.

For Bigg, that last question is direst. Naloxone, which reverses an overdose, is at the heart of CRA’s mission to curb drug fatalities. The group handed out more than 100,000 vial kits this year (up from 25,000 in 2015) and is on pace to reverse 4,000 overdoses in 2017 (about one in seven are fatal). That’s thanks to $600,000 in local and federal government funding, one of Barack Obama’s last initiatives before leaving office.

It’s good timing, given Chicago’s surge in synthetic opioids, like fentanyl, which are difficult to mix and thus much deadlier than heroin. Cook County saw 266 deaths involving fentanyl in the second half of 2016, up from just 87 in the same period of 2015. Explains Bigg: “The demand for opiates has become so huge that the market can no longer meet it. So people go to the lab.”

CRA began primarily as a needle exchange to combat AIDS. But after cofounder John Szyler died of an overdose in 1996, Bigg expanded the group’s efforts to encompass other ways to reduce harm for addicts. That means distributing naloxone and needles, testing for diseases, even teaching users to inject more safely. Such practices have at times landed Bigg in the crosshairs of abstinence advocates, who believe access to naloxone promotes riskier drug use. “But that’s like saying condoms promote sex,” Bigg counters. “Our goal is just to provide techniques to avoid overdose.”

His white whale? A law that would allow him to administer pharmaceutical heroin as treatment—a pillar of public health in Switzerland. “The drug cartels,” he says, “are a lot more scared of me than they are of the police.”