Rescue teams trekking through a ruined coal mine encountered smoke and had to retreat early Friday for fear of fire and another explosion, the latest gut-wrenching setback in the search for four miners missing since the worst U.S. mine disaster in about two decades killed 25 others.
It was the third time since Monday's explosion at Massey Energy Co.'s Upper Big Branch mine that rescuers had to pull back after making their way about 1,000 feet below the surface and about five miles into the massive coal mine. The previous teams had to scramble back to the surface because of dangerous gases that could set off another explosion or fire.
"We had a long night and we had a difficult night," Gov. Joe Manchin said.
Manchin said there was still a sliver of hope for survivors and rescuers carried with them four extra oxygen packs, just in case. But even before they went back underground, officials had started using words like "recovery" and "bodies" more frequently.
Monday's explosion killed at least 25 miners and four others were missing. There have been no signs since the day of the explosion that the four missing miners survived but authorities and their families are hoping they somehow made it to one of two refuge chambers that are stocked with four days' worth of oxygen, food and water.
The first refuge chamber was found empty and when rescue teams tried to get to the second chamber early Friday, that's where they encountered signs of fire and smoke, and had to retreat before they could determine if any miners were inside. Kevin Stricklin, coal administrator from the Mine Safety & Health Administration, said authorities may have to rely on cameras to check out that second chamber.
Search teams had gotten frustratingly close a day earlier to answers for the families of the missing miners -- just 500 feet from the emergency chambers where any survivors would be -- then were ordered to retreat because of volatile gas.
With the air deemed slightly safer four days after the blast and nitrogen being pumped in from above ground to neutralize explosive methane gas, rescuers went back in just before 2 a.m., navigating rubble strewn with bodies, twisted railroad track, shattered concrete block walls and mounds of dust.
To get so close three times, only to have to rush back to the surface again without completing their mission, has been difficult for the crews.
"It's very emotional for all the rescuers," Stricklin said.
Families were also on edge, said Manchin, who briefed the relatives before the news conference.
"We had to walk in and explain to them that we had a situation that no one wanted, but a situation that had to be dealt with," Manchin said.
Stricklin said rescuers reached a first refuge chamber, stocked with air, food and water, and found it unused. They were on their way to a second chamber when they had to withdraw.
"The thing that is unknown is exactly where this fire is at," Stricklin said.
As the world awaited news from the rescue teams inside the mine, more details emerged about the mine's extensive list of safety violations. Federal regulators issued evacuation orders for all or parts of the Upper Big Branch mine more than 60 times since the start of 2009, according to a report prepared for Democratic Sen. Robert Byrd of West Virginia
In 2007, the mine met all the criteria to be declared by the Mine Safety and Health Administration to have a pattern of violations. This would have allowed for stricter oversight by the federal agency, including the potential shutdown of the mine, but Massey was able to reduce the number of the most serious violations and avoid the declaration.
MSHA has appointed a team of investigators to look into what happened, and President Barack Obama said he has asked federal mine safety officials to report next week on what may have caused the blast. Officials have suggested a buildup of methane may have been to blame.
Massey Energy has been repeatedly cited and fined for problems with the system that vents methane and for allowing combustible dust to build up. CEO Don Blankenship has strongly defended the company's record and disputed accusations from miners that he puts coal profits ahead of safety.
Of the 25 confirmed dead, 18 bodies remain inside. Seven bodies were removed earlier in the week. Two other miners survived, and one of them remains hospitalized.
After rescue teams left the mine because of dangerous levels of poisonous gas, they waited around all day Thursday for another chance to go back in. The third trip was expected to be quicker because they had found a short cut to the search area, and would be able to ride on ATVs instead of trudging on foot after the underground rail cars run out of track. They had also left behind a lot of their gear to pick up on the way. Rather than two or three hours, the most recent trip was expected to take half that time.
For days, crews have been drilling holes into the sides of the mine to ventilate lethal carbon monoxide and highly explosive hydrogen and methane gas. Officials preferred that method to reduce the toxic levels, but realized late Thursday that the nitrogen would be needed.
Regina Lilly was at Arvon's Floral in Whitesville buying a black and yellow ribbon arrangement to hang on her front door in support of the miners. She said she has been in rooms where officials let families know what's happening.
"They want answers; they're not getting answers," she said. "They want their family members brought out of that mine; they haven't got that yet."
Associated Press Writers Allen G. Breed, Greg Bluestein, Tim Huber, Vicki Smith and John Raby and videojournalist Mark Carlson in West Virginia; Mitch Weiss and Mike Baker in North Carolina; Ray Henry in Atlanta; and Sam Hananel in Washington contributed to this report.