A 2006 law allows people over age 18 to purchase "sharps" without a doctor's prescription. Since then hypodermic needle litter has been a danger to the public in the streets and parking lots and also poses a threat to police during pat-downs according to a Barnstable police spokesperson quoted in a recent Cape Cod Times article. In less than a year there have been two accidental jabbings of police officers during pat-downs there.
As of July 2012, Massachusetts medical waste regulations forbid disposal of needles in household garbage. The Massachusetts Department of Public Health gives suggestions for safe disposal containers and a list of designated locations for sharps disposal here.