D.C. firefighters had to resort to cellphones after their radios stopped working during the rescue of passengers aboard a stranded train in a smoke-filled tunnel in downtown Washington on Monday, and Metro officials had known for at least four days prior that emergency radios were not working properly in the tunnels.

The full scope of the chaos that D.C. firefighters faced during the worst Metro calamity in six years — they were blinded by smoke and hamstrung by faulty equipment, with no way to communicate and no warning from Metro about the severity of the situation they were entering — came into fuller view Saturday with the release of the District’s first accounting of its response.

For Metro riders and countless others unsettled by the tragedy, the report was the latest in a series of piecemeal and exasperating explanations of why scores of passengers waited at least 30 minutes to be rescued from the train. The incident Monday afternoon near L’Enfant Plaza Metro station ended with the hospitalization of 84 passengers and the death of Carol Glover, 61, a federal contractor and grandmother from Alexandria, Va.

In the realm of assigning responsibility, however, the report appeared to mark a tipping point, addressing some of the biggest questions regarding firefighters’ response time and raising new ones about Metro’s earnestness in following the “safety culture” Metro officials pledged after the fatal 2009 Red Line disaster that killed eight passengers and a train operator .

The District’s report, based largely on accounts from firefighters and 911 call logs, revealed that despite hundreds of millions of dollars in upgrades and new training and safety protocols at the transit agency, a critical piece of infrastructure — emergency communications — remains a significant problem.

As D.C. firefighters dispatched trucks and ambulances — and later, as they descended into L’Enfant Plaza station — first responders were not told by Metro for 20 minutes that a train filled with passengers was stranded in a tunnel, the city’s report said.

Once firefighters were in the station, they were informed of that fact by an officer in the Metro Transit Police, but the first rescue crew could not radio to a battalion chief aboveground for backup.

Had either of two emergency calls placed minutes earlier by Metro, which focused on smoke in the Metro station, also mentioned the possibility of a train with passengers, city fire protocol would have called for a greater response, with at least 25 firefighters descending to the tracks.

As it was, there were just five firefighters, and one had to hold back to try to get a radio signal.

Asked Saturday whether Metro’s operator, the Washington Metropolitan Area Transit Authority, was at fault in Glover’s death, D.C. Mayor Muriel E. Bowser (D) said it was premature to draw a conclusion.

But Bowser called more forcefully than at any point since the incident for Metro to match the District in releasing a full accounting of its actions.

“My job is to find out what happened to ensure that we have a top-down review from our end. We demand that Metro does exactly the same thing from their end,” Bowser said outside a movie screening hours after her office released the report Saturday. “There is a lot to learn from this incident, and we would just compound the tragedy if we did not take those lessons and make improvements.”

Since the incident, Metro officials have cited the ongoing investigation by the National Transportation Safety Board as the reason for their refusal to respond to questions about the event.

Metro spokesman Dan Stessel Saturday repeated that explanation, saying the transit agency would not address the District’s findings: “As a party to the NTSB investigation, federal regulations mandate that all information flow through NTSB. This ensures that the investigation speaks with one voice, that being the independent agency conducting the investigation. We continue to give our full cooperation to the NTSB, including providing interviews, access, documents, data and recordings.”

Tom Downs, whose term as Metro board chairman ends Thursday, and Mortimer Downey, the incoming chairman, did not return calls seeking comment. 

The agency did, however, buy a full-page advertisement scheduled to run in Sunday’s editions of The Washington Post titled “A Letter to Our Riders.”

“We apologize to all Metro riders, and particularly to the family of Carol Glover and those injured or impacted by the events of Monday afternoon,” the letter begins.

“We also want to thank those first responders and passengers who came to the aid of our riders. The incident that occurred on the Yellow Line outside L’Enfant Plaza was harrowing for the passengers aboard that smoke-filled train, and caused a major service disruption for thousands of others. We know that we have to redouble our efforts to learn from this and take every step necessary to make sure it doesn’t happen again.”

The letter, signed by Downs and interim General Manager Jack Requa, promises an “absolute commitment” to a full accounting of the tragedy. It ends: “Your safety, and your trust in Metro to deliver safe and reliable service, is paramount to us.”

D.C. Fire Lt. Stephen Kuhn, head of the first group of rescuers who reached the train Monday, said in an interview Saturday that it was only the calm behavior of the trapped passengers that kept Monday’s death toll from increasing.

He said about 100 people exited the train in the smoky tunnel, stepping down about three feet and onto a 22-inch-wide ledge, before reinforcements arrived to help with the evacuation.

“There was no pushing, no shoving. It was absolutely the most incredible thing I’ve ever seen,” said Kuhn, a 29-year veteran. “If we had active fire and heat, that would have been really bad.”

Kuhn said that when he and his team entered the Metro station believing the problem involved smoke there, protocol dictated that they descend to the track platform and stay near the base of the elevator.

But Kuhn said the team was stunned that the entire station was empty of passengers who by that time had had 13 minutes from the first Metro emergency call to evacuate. Kuhn described an eerie scene as the team began searching for the problem. They encountered a group of Metro Transit Police officers near the end of the platform who told them about the disabled train — a little more than a football field’s length away, but invisible in the smoke-filled tunnel.

Kuhn said he tried to relay the news, but when he pressed a button on his radio, it did not make the chirping sound that indicates an open line. Instead, it “honked out,” he said, using the lingo for an abrasive sound that warns that the radio is out of range for reception.

The problem repeated persisted, and Kuhn said he asked the police officers, one of whom appeared to be on a cellphone call with Metro command, to relay a request for power to the tracks to be cut. The officer said the power had been cut. Four firefighters began walking along a catwalk on the side of the tunnel, with Kuhn instructing one member to hold back and try to get a radio transmission through to the battalion chief outside.

The first team reached the train and was about 10 minutes into the rescue before reinforcements arrived, according to the report.

Metro had been warned four days earlier that D.C. firefighters’ radios were not working in that exact spot.

Firefighters were dispatched to the station at L’Enfant Plaza on Jan. 7, and a supervisor wrote in an e-mail to Metro the next morning that firefighters were unable to get 800-megahertz radio coverage “anywhere in the station.”

A Metro employee, whose name is redacted in the District’s report, wrote back five hours later to say that the subway operator had been “troubleshooting” radio problems in tunnels the previous day and might have had emergency radio bands to L’Enfant Plaza’s station turned off at the time firefighters were dispatched. The employee said Metro was “having trouble with the tunnel areas which we are troubleshooting,” but he seemed to discount the idea that there could be a widespread problem in all of L’Enfant Plaza. “The stations seem fine,” he wrote.

The D.C. fire official, whose name also is redacted, wrote back within minutes, asking Metro to inform the fire department when such maintenance would affect firefighters’ radios.

Kuhn said in a written statement published in the District’s report that firefighters also had trouble extracting passengers once they reached the train.

The first door they came across had no latch for emergency workers to pull. The team asked passengers to open the door by following the emergency instructions inside. But firefighters quickly realized that that would not work and used a special key they carry to open Metro train doors.

For passengers to open doors on four of the six train cars would have required them to remove two screws from above the door, the report said. That system was flagged by the NTSB as a concern after the fatal 2009 crash on the Red Line, and a Metro corrective plan at the time called for all of the doors to be retrofitted with exterior releases for rescuers. According to the Metro plan, all of the doors should have been fixed by last April.

Paul Duggan and Lena H. Sun contributed to this report.