DAVID GREENE, HOST:
All right. It is still a mystery in New Haven, Conn. The authorities there say they are still not sure what was in a batch of synthetic marijuana known as K2. It's believed to be responsible for nearly a hundred overdose cases in the city over the last two days. Davis Dunavin from member station WSHU reports.
DAVIS DUNAVIN, BYLINE: The overdoses started late Tuesday night and Wednesday morning in the historic New Haven Green, the city park that lies in the shadow of Yale University. It was just a few at first. By Wednesday morning, police were dealing with as many as nine overdose cases in one hour. Lisa Ostrowski (ph) is one of the regulars who frequent the Green.
LISA OSTROWSKI: Everybody was dropping like flies. Everybody was OD'ing and convulsing and having seizures, and they looked like zombies out here.
DUNAVIN: People got the K2 from someone who walked through the Green that night, handing it out as if it were a free sample. Police say they've arrested several suspects. Seventy-six people were hospitalized in the first 24 hours, and there were more overdoses on the Green throughout the day Thursday. Dr. Sandy Bogucki is with Yale-New Haven Hospital. She says no deaths have been reported from the outbreak and, in fact, some people were hospitalized two or three times from repeatedly smoking the tainted K2 throughout the day.
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SANDY BOGUCKI: The effects did not last long, and they were able to be discharged, in most cases, from the hospital fairly soon, which meant they were able to return to the Green to seek another high.
DUNAVIN: As Bogucki was speaking at a press conference at City Hall Thursday afternoon, emergency workers were responding to more reports of overdoses on the Green across the street. One of the groups working with the homeless population on the New Haven Green is a homeless shelter called Columbus House. Alison Cunningham is their CEO.
ALISON CUNNINGHAM: K2's been around for a while. What was going around yesterday was something different. And it felt surreal to be on the Green yesterday and watch this happening.
DUNAVIN: Investigators still aren't sure what was different about the K2 that hit the New Haven Green starting Tuesday night. I spoke with Dr. Kathryn Hawk via Skype. She's an expert in drug addiction at Yale-New Haven Hospital. She says K2 is part of a large category of chemical compounds that can cause a wide range of effects based on what's in them.
KATHRYN HAWK: Starting with sleepiness or kind of being chilled out, agitation, psychosis, delirium - all these things have sort of been reported in types of synthetic cannabinoids.
DUNAVIN: Hawk says investigators were worried the K2 might have been mixed with the synthetic opioid fentanyl, which has been responsible for tens of thousands of overdose deaths in the country. The DEA didn't find any fentanyl in tests of samples of the drug. But even as investigators have scrambled to solve the mystery, the overdoses have continued.
For NPR News, I'm Davis Dunavin in New Haven, Conn. Transcript provided by NPR, Copyright NPR.