"Did our dad have to die?" Peggy Cohen wanted to know as mine safety regulators opened an emotional public hearing on questions still surrounding the January disaster that left 12 men dying deep inside the Sago Mine.

Families of the deceased miners held framed photographs of their lost husbands, sons and brothers as they challenged state and federal regulators to improve safety in the nation's mines to spare others the anguish they have lived through.

"We assure you, Mr. Politicians, that we're not going to let this rest. We know in our hearts that this can be corrected. It needs to be done immediately, it needs to be done now. And it's on you," said John Groves, whose brother Jerry was among the 11 men who survived the explosion, but slowly died from carbon monoxide poisoning while waiting to be rescued.

"If another accident happens without safety changes, you are responsible," Groves said looking at officials from the federal Mine Safety and Health Administration and West Virginia's Office of Miners' Health Safety and Training.

It was only the second time MSHA has allowed families to testify at a public hearing, said J. Davitt McAteer, a former MSHA director who is chairing the session.

The families want to know whether lightning caused the blast inside the mine. They also want to know how the false news spread that 12 men were alive and why it took MSHA 11 hours after the explosion before allowing rescue teams to begin search for the trapped crew.

Only one miner, Randal McCloy Jr., was carried out of the mine alive more than 41 hours after the explosion. McCloy was not expected to participate at the hearings and has not yet been interviewed by state and federal investigators.

In a letter to the victims' families last week, McCloy said 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.

Afternoon testimony centered on the mine's safety record in the year before the accident and whether state and federal officials had appropriately enforced regulations.

Kevin Stricklin, MSHA's district manager, defended the federal agency's enforcement efforts and explained how MSHA and mine owner International Coal Group had been working to make the mine safer since ICG took over.

"I do think the mine did seem to be improving in the fourth quarter of 2005," Stricklin said. "It wasn't a perfect mine, but we were working to make a better mine than what it was."

Mine superintendent Jeff Toler, whose uncle Martin Toler was one of the 12 miners who died, said ICG was upgrading escapeways and equipment and implementing new performance programs involving employees.

Jeff Toler said he started underground when the first reports of smoke came from a mining crew that was able to escape from the mine.

"I regret that mine traditions forced us to exit that day," he told the families. "I relive this nightmare in my mind many times over, every day. Only in my mind, we save them every time."

The explosion occurred as crews were preparing to resume production after the New Year's holiday. Two miners entered the mine before the crews entered to check for problems.

One of them, fireboss Terry Helms, is believed to have died in the explosion. The second escaped, but has told federal and state investigators that his inspection report has been lost.

That doesn't sit well with Debbie Hamner, widow of George "Junior" Hamner and the families' representative on the hearing panel. She said another miner recalls Helms reporting "two small violations, but he can't remember what they were."

"My husband's dead, so there's no small violations to me," Hamner said. "This explosion, I believe, was preventable, and I don't call this an accident. I call this a disaster."

State and federal investigators have not determined what caused the explosion and will press ICG to explain why it believes a powerful lightning strike triggered methane gas in a sealed off section of the mine.

The investigation is looking at whether the seal was built properly and if a federal standard that requires them to withstand a force of 20 pounds per square inch is sufficient. A force of 20 psi is equivalent to a 90 to 100 mph wind.

ICG is expected to discuss its internal investigation on Wednesday, but company President Ben Hatfield said Tuesday that none of the 200 citations issued against the mine last year played a part in the explosion.

Regarding the miscommunication, Hatfield said the initial report received at the command center at 11:46 p.m. was 12 miners had survived. It wasn't until 45 minutes later when a rescue crew arrived at a fresh air station that the truth was learned.

"In short, we learned the information was probably not as hoped, but we didn't know for sure," he said. "We frankly didn't know what message to deliver to the families."

But in the end, the families say the hearings are about 12 men who "died doing what they were trained to do."

"They tried to escape, and when they couldn't escape, they went back where they knew they had air, and they barricaded themselves the way they were taught," said Pam Campbell, whose brother-in-law Marty Bennett died. "And as they shared rescuers amongst them, they beat on roof bolts and nobody listened. They waited for blasts from the surface, and those blasts never came."