A 25-year old Port Huron man was found unresponsive by hospital staff in the bathroom at St. Joseph Mercy Port Huron yesterday morning.  Police suspect the man overdosed on heroin, based on the drug paraphernalia found at the scene according to Port Huron Police.  The man was treated at the hospital and released sometime later in the day.   St. Joseph Mercy Port Huron is located at 2601 Electric Avenue and possible charged are pending in the incident, according to reports.