"In total, there were 10,514 injections and 33 opioid-involved overdoses over 5 years, all of which were reversed by naloxone administered by trained staff (Table 1). No person who overdosed was transferred to an outside medical institution, and there were no deaths. The number of overdoses increased over the years of operation, due partially to the number of injections increasing over the same period of time (Fig. S1 in the Supplementary Appendix). The types of drugs used at the site changed over the 5 years of operation, with a steady increase in the proportion of injections involving the combination of opioids and stimulants, from 5% in 2014 to 60% in 2019 (Fig. S2).

"Although this evaluation was limited to one city and one site that is unsanctioned, and therefore the findings cannot be generalized, our results suggest that implementing sanctioned safe consumption sites in the United States could reduce mortality from opioid-involved overdose. Sanctioning sites could allow persons to link to other medical and social services, including treatment for substance use, and facilitate rigorous evaluation of their implementation and effect on reducing problems such as public injection of drugs and improperly discarded syringes."

Source

Kral, Alex H., Lambdin, Barrot H., Wenger, Lynn D., Davidson, Pete J. Evaluation of an Unsanctioned Safe Consumption Site in the United States. New England Journal of Medicine. July 8, 2020. 10.1056/NEJMc2015435.