Power was being restored Friday to the White House and thousands of electric customers in downtown Washington, but Metro train traffic remained snarled after a second fire on the tracks near Metro Center.
It wasn't immediately clear whether the fires were being caused by the power outage, though power problems have been blamed in the past for Metro track fires.
The track fire is the fourth major service issue for the train system in the last 10 days, reports the Washington Post.
Metro spokeswoman Taryn McNeil said trains were stopped and the Metro Center station was closed just before 10 a.m. because of a fire on the red line tracks. The first fire was reported about 7:30 a.m. Officials don't know what caused the fires to ignite on the tracks near Metro's major hub, McNeil said.
"We don't want to speculate at this point," McNeil said.
Fire department spokesman Alan Etter said many people complained of breathing difficulties at the Dupont Circle station, where escalators weren't working because the outage. Nine people were treated, including a 50-year-old man who was taken to a hospital because of problems with his implanted defibrillator.
Transit officials said riders should expect major delays of more than an hour through the morning. Free shuttle buses are available at the Gallery Place-Chinatown, Farragut North and Metro Center stations.
The White House was among the buildings affected by Friday's power outage.
"The White House had been running on generator power, and all essential functions were operational," said deputy press secretary Tony Fratto.
Pepco spokesman Bob Dobkin said workers had identified a problem with equipment at an electrical substation in the Chinatown area. By 10 a.m., power was being restored to a large portion of the customers affected. At one point, Pepco was reporting more than 18,000 customers were without power.
The outage also cast the power utility's downtown headquarters into darkness. A backup generator provided power for some lights and phones, Dobkin said.
"We certainly know what our customers are experiencing," he said.
Mary Wallace of Alexandria said she arrived at work at a consulting firm downtown at 9 a.m. and was told the power was off. About half an hour later, she said she was taking it as a sign that she'd get an extra day off.
"Word has it that our office is officially closed. I'm watching someone's bag and as soon as she comes back, I'm out of here," she said.
Brian McDonald, a 27-year-old District of Columbia resident who works for the federal government, said he felt lucky because a lot of federal employees start their day at about 6:30 a.m., but he had arrived at 8:45 a.m. After about an hour of standing outside his office building, he was told he was free to go. Power was restored shortly afterward.
"I'm going to hit the links right now," McDonald said.