He said there were a dozen overdoses in 40 minutes on the green on Wednesday morning.
"Throughout the day [Wednesday] it was extremely busy, we had six or seven people at the same time, kind of put a little bit of stress, not only on emergency services personnel, EMS personnel, but throughout the entire city", said Rick Fontana, New Haven Office of Emergency Operations.
The Rev. Luk De Volder, rector of the historic Trinity Church on the Green, told the paper there were ambulances on the Green on Monday night as well. He said the Green has become "a place of despair" and "no longer an attraction for families or economic development".
"The Police Department is aware of a high number of patients that were treated since last night, including as many as six now".
New Haven police said they'll provide more details during a news conference at 1 p.m. Stream it here. Some individuals who were released from the hospital needed to be treated a second time for an additional apparent overdose, Fontana said.
A suspect is in custody after over 40 individuals overdosed in a CT park on a drug suspected of being laced with an opioid, police say.
A doctor at one hospital says some patients tested positive for the powerful opioid fentanyl, but it appears most of the overdoses were caused by a potent batch of straight "K2" synthetic marijuana.
Three arrests have been made in the case, Hartman said, but officials can not say for certain if all three arrested or just one of them are directly responsible for the overdoses.
Officials described a hectic scene as emergency crews worked to respond to all of the overdose reports.
"Do not come down to the Green and purchase this K2", New Haven Police Chief Anthony Campbell warned, according to WABC-TV.
Dr. Kathryn Hawk, an emergency physician at Yale New Haven Hospital, told the New Haven Register on Wednesday that the Drug Enforcement Administration had "confirmed the presence of fentanyl in some of the overdose cases".
Emergency responders spent several hours today working to treat the victims and transport them to the hospital.
Synthetic opiates like fentanyl, which is 30-50 times more potent than heroin, are extremely unsafe. The DEA also says there were no additives in the K2.
Synthetic marijuana, called "spice" and other names, usually is plant material sprayed with chemicals or other substances.
The Town of Hamden wants to remind people who use any street drugs can, and may, result in death or serious medical complications.