Kentucky State Police are still investigating the cause of the Stanford explosion that killed former state trooper Shannon Corman on Tuesday.
Corman, who was a federally licensed firearms dealer, was mixing a large amount of black powder in a garage behind his home on Oak Street when the explosion occurred, police said.
"At this point, we believe there might have been some mishandling of the black powder," state Trooper Chris Lanham said. "We do not have the cause of the ignition source. Probably, we will never know."
Static electricity and electrical outlets are being investigated as ignition sources, Lanham said. Several electric space heaters were recovered from the scene, but there was no indication they had been on, he said.
James Greenwood, 57, who was helping mix the black powder, and Corman's wife, Louise Corman, 75, were injured and taken by helicopter to University of Kentucky Hospital. Greenwood was in critical condition Friday morning. Louise Corman had improved from serious to fair condition.
"We're hoping, if we can talk to them, that can shed more light on, if (the heaters) were being used," Lanham said.
Shannon Corman, 80, retired from the police force in 1982.
He owned a gun shop in Stanford at one time and was known to custom-mix black powder for hunters.
"He was very experienced with handling those materials," Lanham said.