Five workers died on Tuesday after they were trapped deep underground at a hydroelectric plant near Georgetown, Colorado, amid a chemical fire, power company Xcel Energy Inc said.
The five outside contractors were putting on an epoxy coating to an underground pipeline in preventive maintenance at the Cabin Creek Station when the fire broke out.
Tim Taylor, president of Public Service Co. of Colorado, an Xcel Energy company, announced the deaths and his condolences. "Certainly, we'll be working closely with the authorities to investigate what happened," he said in a statement.
After the fire, the workers climbed a safe distance from the blaze and were communicating with plant operators by radio, Xcel said. Spokesman Tom Henley said he did not know how long the men had been in contact after the fire broke out or how long they were waiting to be rescued.
Four other workers were able to leave the pipeline alive.
Firefighters from the Clear Creek County Fire Authority battled the blaze and it was eventually extinguished, Henley said. The plant was shut down for routine maintenance at the time, the company said.
The pipeline is between 1,500 and 2,000 feet (460 and 610 meters) below ground and carries water from a reservoir to power turbines inside the plant.
The power station, west of Denver, has two turbines and a generating capacity of 324 megawatts.