The only survivor of a January coal mine blast in West Virginia reveals more details of the desperate struggle of the dozen trapped men.
Randal McCloy says at least four of their air packs didn't work.
He says he and his co-worker shared the functioning air packs even as they pounded away with a sledgehammer in hopes of signaling rescuers.
The revelation was part of a letter McCloy wrote to the family members of the 12 men who died.
Mine owner International Coal Group says all the packs were within their manufacturer's suggested life.
The Ashland based company also says the devices are thoroughly inspected every 90 days by a trained person and are visually checked each day by the wearer.