 Mike Phillips, WDEL Delaware's News Radio. The Maryland Fire Marshal's Office investigating the cause of an overnight fire at Captain Zach's Crab Shack south of Elkton. Firefighters from Singerley and Newark responded to the fire just before 4 a.m. Fire officials say Sarge's market was not damaged, but crews remained on the scene for several hours while a 500-pound propane tank was allowed to burn off. At this point, investigators say there's no sign the fire was intentionally set.