NEW YORK (CBSNewYork) — Mayor Bill de Blasio has signed bills to crack down on the use of synthetic marijuana, also known as K2.

This, as some claim that stepped up NYPD enforcement has not stopped the flow of the dangerous drug on the streets of New York City, CBS2’s Marcia Kramer reported.

It’s not unusual to see people acting out in the area around Lexington Avenue and 125th Street in East Harlem — what officials call the epicenter of the K2 epidemic.

The drug, a dangerous and sometimes poisonous mix of herbs and chemicals, is widely used among the homeless population who congregate there.

“I used to buy K2 here,” said Catherine Turner.

Turner, who lives in a Bronx homeless shelter, said she stopped using K2 after she nearly died. But she said not even an NYPD task force can stop the K2 trade if you know where to go.

“(Kramer: Can you still buy it here?) Yea, over there on the corner they still it. Regular people like me, they sell $2 blunts. And on Third Avenue and 49th Street, and 148th and Bergin Avenue they sell it,” said Turner.

All this as de Blasio signed two bills into law to give the police new tools to stop the use of synthetic marijuana.

The bills bar the manufacture and sale of the drug, and allows the city to revoke the license to sell cigarettes from any store that is caught selling K2.

“Let’s be clear, K2 is a poison. It is a poison that threatens public safety and public health,” said the mayor.

Since January, more than 4,500 people were brought to hospital emergency rooms for K2 poisoning; 1,200 in July alone, Kramer reported.

“There should be no question that this is dangerous stuff and that it has untold health consequences,” said Health Commissioner Dr. Mary Bassett.

Minutes before de Blasio started his news conference, there was an unexpected announcement from Gov. Andrew Cuomo that his office had errected a billboard in the Bronx warning that K2 can kill.

The governor also released a series of dramatic public service announcements.

The rocky relationship between Cuomo and de Blasio is no surprise. The governor has big-footed the mayor on a number of high-profile issues in recent months, including the response to Legionnaires Disease in the Bronx and several gas explosions in the city.

Asked about Cuomo’s K2 initiative, the mayor said he just hear about it, but that it was kindred and welcome, Kramer reported.