San Francisco could be one step closer to opening a supervised drug use site after the Board of Supervisors approved the purchase of property for that purpose. Though supervised consumption sites are currently illegal under federal and state law, Mayor London Breed, backed by many supervisors, is pushing to open one.The approved agreement to purchase adjacent properties stated that the buildings would be used to serve people with behavioral health needs, not specifically for a supervised drug consumption site. The Board watered that down even further with a last-minute amendment by Supervisor Matt Haney that added the site wasn’t authorized for “any specific use” and the city “has not committed to a specific use or project on the site.”