The men who died from carbon monoxide poisoning at an eastern Kentucky coal mine Saturday were using the exact air pack model as the Sago Mine disaster victims, even though the lone survivor had questioned the reliability of the devices about a month ago, according to the Associated Press.

Holly McCoy, spokeswoman for the Kentucky Office of Mine Safety and Licensing, said the self-contained self-rescuers, or SCSRs, used were the exact models the Sago miners were using: CSE SR-100.

Based on preliminary tests, a coroner said Sunday that three of the five Kentucky miners who died in a Harlan County mine Saturday survived the initial blast but succumbed to carbon monoxide. A sixth miner made it out alive.

David Dye, acting administrator of the U.S. Mine Safety and Health Administration (MSHA), said in a statement Monday that the air pack of Kentucky's survivor had worked properly.

"Rescue workers who encountered the survivor during his escape independently corroborated that the survivor was using his SCSR when they encountered him," Dye said.

Randal McCloy Jr., the lone survivor of the Sago disaster that killed 12 miners in January, said in a letter to the victims' families last month that at least four of his crew's air packs had failed, forcing the men to share what little oxygen they had as the mine filed with smoke and carbon monoxide.

A U.S. Senate panel last week approved a bill that would require miners to have at least two hours of oxygen available instead of one as required under the current policy. It also would require mine operators to store extra oxygen packs along escape routes.

Saturday’s explosion was the deadliest mining incident in Kentucky since 1989, when ten miners died in a western Kentucky mine blast, state officials said. The national death toll from coal mining accidents this year is 31, with ten of them in Kentucky.