Authorities say more than 30 people have overdosed from suspected synthetic marijuana at or near a CT city park.
Officials said most of the overdoses happened on the New Haven Green throughout the day on Wednesday.
Three overdoses took place on Tuesday night, with dozens of others happening on Wednesday.
K2 is a synthetic cannabinoid related to marijuana that is frequently laced with other drugs, said Dr.
NEW HAVEN, Conn. The number of overdose victims linked to a suspected bad batch of synthetic marijuana has risen to 76 in New Haven, Connecticut, as officials try to determine exactly what sickened people.
Police say there haven't been any deaths linked to the overdoses, although two people were hospitalized in critical condition.
While the drug tested by the Drug Enforcement Administration was straight K2, some tested at Yale New Haven Hospital showed traces of fentanyl.
Police reportedly made one arrest Wednesday, though the charges were not clear.More news: Trump 'cites Russian Federation probe' after ending ex-CIA head's security access
Campbell said New Haven provides an array of services to people addicted to drugs, many of whom come from other towns where such treatment programs aren't available.
"Another person down on the green", Amy Hudak, a reporter for WTNH tweeted from the scene.
"This is a problem that's not going away", New Haven Fire Chief John Alston Jr. said, according to WVIT.
Police and fire officials said the K2 was potentially laced with some type of opioid. Responding personnel found individuals suffering from "a multitude of signs and symptoms ranging from vomiting, hallucinating, high blood pressure, shallow breathing, semi-conscious and unconscious states", he said in an email.
The mass overdose came as the US Centers for Disease Control and Prevention (CDC) released provisional figures showing 70,689 people died from drug abuse a year ago. The additives boost the high, but can create a unsafe, sometimes deadly cocktail.
"Today New Haven was on the front lines of a coast-to-coast struggle to combat the public health menace of illicit distribution and use of what appear to be tainted street drugs", said New Haven Mayor Toni Harp in a statement.
The fire department gave the affected individuals naloxone, a drug used to treat narcotic overdoses in emergencies, but those doses were reportedly ineffective.
The overdoses follow a similar outbreak at the same park on July 4, when more than a dozen people were treated. So far, there have been few scientific studies of the effects of synthetic cannabinoids on the human brain, but researchers do know that some of them bind more strongly than marijuana to the cell receptors affected by THC, and can produce much stronger effects.