San Francisco officials are working to revamp the city's needle exchange program after residents complained about finding used needles in playgrounds and parks, reports the San Francisco Chronicle. Only 65 to 70 percent of the 2.4 million needles doled out by the city reportedly get returned—compared to return rates higher than 90 percent in cities including Portland and Seattle.

City officials hope to combat this problem by setting up a locked, 24-hour drop box in a confidential area and to meet with manufacturers of high-tech retractable syringes, which have needles that withdraw into the syringe barrel after each use.