Commuters are demanding information after an electrical malfunction filled a Washington subway tunnel with smoke, forcing hundreds to evacuate and sending dozens to the hospital.

Was the train's evacuation Monday afternoon unnecessarily delayed? Were passengers given the right information? And what caused the death of a female passenger? Authorities in the nation's capital had no immediate answers Tuesday.

At a news conference, DC Mayor Muriel Bowser declined to give details on how quickly the fire department responded, beyond saying firefighters got to the scene in their "customary" timeframe. City officials also declined to make the fire chief or the head of the city's 911 center available to answer questions.

Bowser said her administration is reviewing the response and will release its findings next week.

"We will find out what happened, get to the bottom of what happened and commit to fixing it," said Bowser, who took office a week-and-a-half ago.

Metro board chairman Tom Downs apologized to riders who were injured, frightened or inconvenienced. He said the investigation "will be a thorough process that often takes time." Metro service, which had been affected Tuesday by the incident, was expected to operate normally Wednesday.

The malfunction happened about 3:30 p.m. Monday near L'Enfant Plaza, one of the subway's busiest stations. The stop is near the Smithsonian's National Air and Space Museum and many federal office buildings, including the headquarters of the National Transportation Safety Board, which is leading the investigation.

A six-car subway train had just pulled out from the station when it ground to a halt and foul-smelling smoke began filling the tunnel and the cars. NTSB investigator Michael Flanigon said the smoke started when something came into contact with the high-voltage third rail and caused an electrical arc.

In the fear and chaos that followed, riders prayed but also helped one another, performing CPR on an unconscious woman and offering an inhaler to a man curled in a fetal position on the train's floor. Some waited for rescuers as instructed; others opened the doors of the train and made their way to safety through the darkness on their own.

Andrew Litwin, 21, a University of Texas student visiting the Washington area, said some passengers yelled, "We're going to die here!"

The woman who died was identified Tuesday as 61-year-old Carol Glover of Alexandria, Virginia. She was the first fatality on Washington's Metro system since a 2009 crash killed nine people. Glover was an analyst for DKW Communications, an IT company that does work for the government, and was working on a contract with the U.S. Department of Agriculture at the time of her death, said her supervisor Cliff Andrews.

The Metrorail system, which connects Washington with the Maryland and Virginia suburbs, carries an average of 721,000 passengers each weekday. Smoke and fire are not unusual on the subway system, which opened in 1976 and still uses some original rail cars. Metro's most recent safety reports showed 86 incidents of smoke or fire in 2013 and 85 through the first eight months of 2014.

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Dishneau reported from Hagerstown, Maryland. Associated Press Writer Ben Nuckols in Washington also contributed to this report.