New York City is preparing two supervised injection sites—also known as overdose prevention centers—to begin operating as soon as Tuesday. The two facilities, located in East Harlem and Washington Heights, will allow medical personnel to monitor people using drugs like heroin. Clean needles, naloxone, and addiction treatment services will also be available to users, who will bring their own drugs. The centers are the first government-sanctioned spaces for injected drug usage in the country.

The city’s health commissioner, Dr. David A. Chokshi, said the re-organization of the sites, already operating as needle exchange centers, was an attempt to battle a wave of recent overdose deaths. “Every four hours, someone dies of a drug overdose in New York City,” he told The New York Times. “We feel a deep conviction and also sense of urgency in opening overdose prevention centers.” Opponents have argued the sites are magnets for abuse and drug dealers but they’ve been successful in reducing overdoses in Australia and Canada. “After exhaustive study, we know the right path forward to protect the most vulnerable people in our city,” Mayor Bill de Blasio said in a statement. “And we will not hesitate to take it.”