A nearly century-old house in the 200-block of Mount Vernon Avenue and most of its contents were destroyed by fire Sunday morning. The Office of the Maryland State Fire Marshal determined that the fire was accidental and originated in the exterior front porch soffit. The occupant had been doing home improvements with a heat gun the day before, Deputy State Fire Marshal Brad Childress said. No one was home when a passerby reported a fire on the roof at 221 Mount Vernon at 5:49 a.m. Sunday Volunteer firefighters battled the fire for about two and a half hours before bringing it under control and were on the scene for more than four hours. Several firefighters were evaluated at the scene for heat exhaustion but were not transported to the hospital, according to a post on the Chestertown Volunteer Fire Company's Facebook page.