They say no deaths have been reported so far, but at least six victims were near death. The patients were taken to area hospitals for overdose-related respiratory illnesses, Officer David Hartman said.
Drugs, particularly fentanyl, are now deadlier in the U.S. than either HIV, vehicle crashes or guns, the report said.
The overdoses were concentrated on the New Haven Green but because it's now dark the incident is beginning to branch out to different parts of the city, where more people are being found, police said.
"Two individuals had life-threatening symptoms, and the others had non-life-threatening symptoms", he said.
A new report estimated a record 72,000 Americans died a year ago from drug overdoses, a rise of around 10 percent, the Centres for Disease Control said on Wednesday. "Whatever they're putting in it, people are dropping", Driffin told The New Haven Independent.
Campbell said it appears one of three suspects who were arrested was giving the drug away for free in an effort to get people hooked. Chief Mark Vendetto, New Haven Fire Department. The danger lies in the drug's unpredictability and its tendency to be cut with potent opioids or in some cases an anticoagulant used in rat poison.
The mass overdose began Tuesday night and forced police to continue monitoring the Green late into Wednesday night.
They're also hoping to deter others from coming here and trying to find the toxic K2.
Emergency responders treated most of the victims with naloxone, which reverses the effects of the drug. Some individuals who were released from the hospital needed to be treated a second time for an additional apparent overdose, Fontana said.
As Fire Chief John Alston Jr. spoke to reporters in New Haven, Connecticut, about a spate of drug overdoses on Wednesday, he heard shouting coming from behind him.
"It's a synthetic, a man-made product so you never know what they're putting in it", said Asst. The state Department of Public Health and the Department of Mental Health and Addiction Services have been assisting New Haven officials throughout the day.
Most of the overdoses occurred on the New Haven Green, a downtown park adjacent to Yale.
In a warning last month signed by top federal officials, the Food and Drug Administration said synthetic marijuana has become particularly risky because some producers have been adding brodifacoum - a long-acting anticoagulant thought to extend the drug-induced "high".
"I think this is a lot more than we have normally seen".
New Haven Mayor Toni Harp said the state has pledge to help the Elm City.