Matthew Chase had just filled up the gas tank of a 32-foot powerboat at the Ashley Marina in Charleston, South Carolina, at about 9:45 on Memorial Day morning. Chase, who works at Ashley, one of the most popular stops for boat owners cruising on the ICW nearby, said, “I stepped back like we always do, standard procedure, and then he went to start the boat and it must have sparked something and it blew up.” Chase was worried that the boat fire could set off a larger fire at the fuel dock, “so I ran pretty far away.” The two…