It has been nearly 30 years since the first needle exchange program opened in the United States. America has another epidemic now: overdose deaths from opioids, heroin and fentanyl. A thousand people died of overdose in the city last year — three times the number who were killed in homicides. Nationally, drug overdose has passed firearms and car accidents as the leading cause of injury deaths. Yet there is a potent weapon that we’re ignoring: the supervised injection room. According to a report by the London-based group Harm Reduction International, 90 supervised injection sites exist around the world.