The Washington County Coroner’s office was dispatched to 11,057 Coal Ford Road north of Okawville at 7:24 PM on Friday.  50-year old David Martin of Addieville was at his father-in-law’s auto repair shop at this address working on a small pickup truck.  Martin appeared to have jacked the truck up and was lying underneath the vehicle working on the undercarriage when for some reason, the jack slipped and the vehicle fell onto him.  Martin was last seen around 4:30 PM and was discovered by his father-in-law at approximately 6:45 PM, when he failed to answer his cellular phone.  Martin was pronounced dead at the scene at 7:47 PM by Washington County Coroner Mark Styninger.  Cause of death was determined by Coroner Styninger to be asphyxiation due to chest trauma and the manner of death was accidental.  No autopsy was performed.  Agencies responding to the scene included the Addieville Fire Department, the Washington County Ambulance Service, the Washington County Sheriff’s Department and the Washington County Coroner.