A timeline of the fatal Metro smoke incident and the subsequent investigation.
Jan. 12: An arcing third rail shortly after 3 p.m. filled a tunnel and the L'Enfant Plaza station with smoke. A woman on a train that stopped in the tunnel died of respiratory failure due to smoke exposure. Dozens of others were hospitalized.
Jan. 13: Mayor Muriel Bowser announces there were radio communication problems inside the tunnel during the emergency response.
Jan. 15: City Administrator Richard Young releases a preliminary timeline on the emergency response to the incident.
Jan. 16: The NTSB releases its preliminary report, which finds the arcing third rail continue to be supplied with power for 30 minutes after smoke in the tunnel was reported.
Jan. 21: Members of the National Capital Delegation, Congress members who represent Washington and its Maryland and Virginia suburbs, met with leaders from the NTSB and the Washington Metropolitan Area Transit Authority about the investigation into the tragedy.
Jan. 23: Testing in the Metro system found nine locations where radios failed.
Jan. 24: A report released by D.C.'s Homeland Security and Emergency Management Agency says radio encryption issues did not play a direct role in communication difficulties experienced during the incident.
Jan. 31: Follow-up radio testing found one location, in the tunnel between Benning Road and Capitol Heights, where radios failed again.
Feb. 2: Testing in Montgomery County finds an issue with radio coverage at the Wheaton Station. The issue is fixed and no issues are found at 11 other stations in the county.
Feb. 4: D.C. says the radio failure in the tunnel between Benning Road and Capitol Heights is fixed.
Feb. 4: The U.S. Department of Transportation announces it will conduct a safety management inspection of the Washington Metropolitan Area Transit Authority beginning March 2.
Feb. 5: D.C. Council holds a hearing examining how prepared the city is for emergencies on the subway system.
Feb. 11: In a letter to interim General Manager Jack Requa, NTSB said Metro should assess its ventilation system, write a procedure for tunnel ventilation and establish ongoing ventilation training for control center staff and emergency responders. The letter offered more details about how the ventilation system failed. Metro and the NTSB briefed the Council of Governments on the investigation.
Feb 17: Documents show that Metro drafted paperwork to improve its outdated computer software that handles smoke emergencies months before the Jan. 12 incident at L’Enfant Plaza, the Washington Post reported. Metro responded saying that “WMATA is working to improve training and operating procedures."
March 24: New evidence from D.C.’s Homeland Security and Emergency Management Agency reveals water leaking onto electrical equipment created smoke in L’Enfant Plaza incident.
April 7: Loudoun County fire officials build a small model section of Metrorail tracks to train firefighters to respond to future emergencies on the tracks.
April 8: Federal government creates Metro Safety Commission to oversee safety issues at Metro. The new commission will have the power to require Metro to implement its guidelines and policies.
June 8: NTSB issues a safety recommendation regarding smoke incidents after an inspection revealed that some power cable connections in Metro’s tunnels are not installed to specifications. The electrical connections to rails were improperly constructed and installed which allowed moisture and contaminants to get in and potentially cause short-circuiting, smoke and fire.
June 17: FTA releases report finding 90 safety issues — 77 on the rail side and 13 on the bus side.