Almost as soon as the young man crouching on a trash-strewed street in Brooklyn pulled out a crumpled dollar bill from his pocket and emptied its contents of dried leaves into a wrapper, he had company. A half-dozen disheveled men and women walked swiftly to where the young man was rolling a cigarette of a synthetic drug known as K2 to wait for a chance to share.
The drug has been the source of an alarming and sudden surge in overdoses — over three days this week, 130 people across New York City were treated in hospital emergency rooms after overdosing on K2, almost equaling the total for the entire month of June, according to the city’s health department. About one-fourth of the overdoses, 33, took place on Tuesday along the border of Bedford-Stuyvesant and Bushwick, the same Brooklyn neighborhoods where, despite a heightened presence of police officers, people were again openly smoking the drug on Thursday.
In response to the overdoses, the city is sending a health alert to emergency rooms and other health care providers warning about the drug. The outbreak comes after officials this spring lauded what they described as a successful campaign to severely curb the prevalence of K2.
On Thursday, Gov. Andrew M. Cuomo announced that the State Police would step up enforcement against the drug and aggressively go after merchants who illegally sell it.
The same day, just steps from where people were using the drug, clusters of police officers patrolled beneath the elevated subway tracks along a stretch where, the day before, five bodegas had been raided. K2 is typically sold by convenience stores, though the raids did not turn up any.
Milling among the police were people — some of whom wore hospital socks or medical identification bands around their wrists — who said they had overdosed and woken up in Woodhull Medical and Mental Health Center this week. Every so often, they asked passers-by for K2.
“I blacked out. I woke up and I was listening to the machines, at Woodhull. They said, ‘You passed out; you overdosed on K2,’” said Ditrell Barnes, 30, a day after he had been found unconscious by emergency workers near Myrtle Avenue, where he now stood, peeling the gauze over the marks an IV insertion had left on his right arm. Every so often he interrupted himself to ask people on the street if they had “sticks” or cigarettes of Spice, as the drug is sometimes called.
“I would just rather have more of it, than less of it,” he said. “It’s like food for me. It’s like produce. It’s like something for my brain.” He added that without it, he now feels “this empty void — it’s like I need that nutrition.”
Health and law enforcement officials have attributed the recent overdoses, including those on Tuesday, to a bad batch of the product, rather than on an overall rise in the use of the drug.
K2 is “wholly man-made, made by persons unknown, assembled by persons unknown, under unknown conditions in unknown places,” said Robert Messner, the Police Department’s assistant deputy commissioner for civil enforcement, during a news briefing at the Police Academy in Queens.
A chemical is typically sprayed over leaves, giving it the appearance of marijuana, but, Mr. Messner said, it is closer to more virulent drugs such as bath salts.
Users say the effect of a good high is clarity and euphoria, and a bad high can cause hallucinations or uncontrollable rages. Some users become stupefied, earning them the derisive term “zombies.”
“The users of K2 are literally playing Russian roulette with their bodies,” Mr. Messner added. “They have no idea what chemicals are in that package or at what concentration.”
Police Commissioner William J. Bratton, who was also at the academy, pledged a renewed focus on K2 and noted that much of the drug’s activity in the city appeared to be happening near methadone clinics. Most sales occur at bodegas, Mr. Bratton said, adding that it was tantamount to store owners’ “poisoning their customers.”
“We have enough problems in the city of New York,” he added, “trying to deal with the mentally ill, the drug addicted, trying to keep neighborhoods safe, without the greed that drives this.”
Despite the recent increase, K2-related emergency room visits have abated since a peak last summer, when in July 2015 there were about 1,200 emergency room visits related to the drug, according to the health department. There were 10 deaths in 2015 linked to K2, nine of which involved other substances. A spokesman for the department, Christopher R. Miller, said he was not aware of any K2-related deaths this year.
A campaign of raids and arrests, as well as new city legislation that banned more forms of the synthetic drug and threatened businesses and owners who sold the substance with closings, fines and jail time, contributed to what had appeared to be a dip in K2 use. The 140 emergency room cases related to the drug in June had been the lowest monthly total in more than a year, Mr. Miller said.
But underneath the elevated subway tracks on Thursday, brightly colored foil squares of K2 brands with names like Mr. Happy and Green Giant littered the pavement. Hand-painted signs saying “No K2” hung on the fence of a community garden.
Some residents in the neighborhood said the area had been flooded with users since the weather started to warm — in some cases, they recounted seeing people, apparently high, rip off their clothes and run screaming into traffic.
They were puzzled by the city’s numbers showing a drop in emergency room visits.
“If it went down, how could it spike within a day or two?” Jennifer Williamson said as she sat on a bench on Broadway, while nearby a man wearing hospital socks slept. “It never went down.”
On the Brooklyn streets where the majority of the overdoses took place this week, at least one man was rethinking his use of K2. As he tried to sell a phone to passers-by, the man, who asked that his name not be used because of his drug use, said that a few hours earlier, when a friend had asked him for some K2, he had given him a bag of marijuana instead, telling the friend it was safer.