K2 can cause extreme anxiety, confusion, paranoia, hallucinations, rapid heart rate, vomiting, fainting, kidney failure and reduced blood supply to the heart. Victims were lying on the sidewalk, shaking and leaning against trees and fire hydrants. They were even sleeping in the street. They were taken to Woodhull and Wyckohoff hospitals. It was an apparent mass drug overdose despite warnings from police and health officials about the dangers of using K2. “No Smoking K2” signs were placed in the streets. The Health Department monitored emergency rooms across the city. The city cracked down on the drug last year, making it a crime to sell K2. Residents have even posted warning signs reading.