Ventilation fans pulled smoke toward a train full of trapped passengers in the Jan. 12 Metro incident that left one woman dead and sent more than 80 passengers to the hospital, the National Transportation Safety Board has determined as part of its ongoing investigation. As a result, NTSB issued its first urgent safety recommendation today in the incident’s aftermath, aimed at preventing these ventilation issues.
Ventilation fans can be set to two different modes: one that brings in fresh air from the outside, and one that pulls air from tunnels and stations to the outside. Typically, the fans act in tandem, allowing fresh air to replace the air inside the stations and tunnels. After a Yellow Line train stopped south of the L’Enfant Plaza station on Jan. 12, Metro activated the under-platform fans in exhaust mode, which brought smoke from the electrical arcing event on the third rail toward the train. At the same time, the other set of fans was also in exhaust mode, so no fresh air was able to enter and facilitate the removal of smoke. Additionally, the train operator failed to shut off the train ventilation system that brings air into the train from outside, and so smoke filled the train.
Acting NTSB Chairman Christopher Hart presented these findings to a meeting of regional leaders today at the Metropolitan Washington Council of Governments. NTSB’s investigation is ongoing, but the agency issues urgent safety recommendations when it discovers a problem that could cause further issues if not addressed immediately. It did so today, providing guidelines on safer ventilation procedures.
MWCOG board members questioned Metro officials sharply at the hearing. Jack Requa, interim general manager of the Washington Metropolitan Area Transit Authority, which runs Metro, testified, “On a monthly basis we have checked all of the fans in the system.” Metro appears not to have been aware of any problems with the ventilation fans around L’Enfant Plaza. Hart stated that two of the four fans in the shaft by the incident location had blown circuit breakers, although it was unclear if the problem was caused by the incident or predated it.
NTSB is conducting a deliberate and sometimes secretive investigation, leading to a two-day public hearing in June. Hart emphasized multiple times to MWCOG, “It’s very important that the [involved] parties don’t go to the media with any information,” given that “partial information can be very misleading.” MWCOG members expressed concern that NTSB is not holding a hearing until June. Hart said the agency had to interview several dozen witnesses, review video from more than 100 cameras, and investigate materials from the incident site before holding the hearing.
“We need to gather quite a bit of information to have a meaningful hearing,” Hart said, adding that “transparency is a very important part of our process.”
Metro has been playing safety catch-up for years. According to WMATA Chairman Mortimer Downey, NTSB issued 29 safety recommendations to Metro stemming from the 2009 Red Line crash that killed nine people and earlier incidents. Metro has completed 25 of them, and is working on the remaining four.
Metro and D.C. fire officials have sniped at one another over responsibility for a breakdown in radio communications in the L’Enfant tunnel. That dispute continued today, as Requa testified, “Jurisdictions are responsible for their own testing.” D.C. fire officials had blamed Metro for not fixing radio communications after a warning that they weren’t working, while Metro countered that the fire department had encrypted the communications without informing Metro.
The immediate cause of the smoke incident is clear, says Hart: It came from electrical arcing, defined as sparking or smoke on the electrified third rail. “We’re not trying to figure out what happened,” Hart explained. “We’ve known that for a long time. That was arcing. We want to find out why.”
Metro has experienced arcing about once a month, according to a 2013 Metro report. Questioned by Montgomery County Councilmember Roger Berliner about the frequency of arcing incidents, Downey responded with an answer that seemed to sum up many of Metro’s problems.
“They are a symptom,” he said, “of an aging system.”
Photo via NTSB