Mass Casualty Incidents | News | Slideshow

D.C. Subway MCI

01 / 12

Metro Station Smoke

A woman coughs hard as she and another woman walk past an evacuation of people from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) A woman coughs hard as she and another woman walk past an evacuation of people from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

02 / 12

Metro Station Smoke

A man with a tie that says "Police Line Do Not Cross" waits in a triage line after being evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) A man with a tie that says "Police Line Do Not Cross" waits in a triage line after being evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

03 / 12

Metro Station Smoke

Metro Transit Police officers secure the entrance to L’Enfant Plaza Station in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Manuel Balce Ceneta) Metro Transit Police officers secure the entrance to L’Enfant Plaza Station in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Manuel Balce Ceneta)

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Metro Station Smoke

Metro Transit Police officers, secure the entrance to L’Enfant Plaza Station in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. (AP Photo/Manuel Balce Ceneta) Metro Transit Police officers, secure the entrance to L’Enfant Plaza Station in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. (AP Photo/Manuel Balce Ceneta)

05 / 12

Metro Station Smoke

An FBI Medic, center, helps people onto a bus after they were evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) An FBI Medic, center, helps people onto a bus after they were evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

06 / 12

Metro Station Smoke

A couple holds hands as the man coughs while speaking with a firefighter after people were evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) A couple holds hands as the man coughs while speaking with a firefighter after people were evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

07 / 12

Metro Station Smoke

A woman is transported in a wheelchair onto an ambulance bus as people are evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) A woman is transported in a wheelchair onto an ambulance bus as people are evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

08 / 12

Metro Station Smoke

Coughing people are sorted for triage needs after being evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) Coughing people are sorted for triage needs after being evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

09 / 12

Metro Station Smoke

A firefighter attends people on a bus to assess triage needs after people were evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) A firefighter attends people on a bus to assess triage needs after people were evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

10 / 12

Metro Station Smoke

Coughing people are taken onto a bus as they are evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) Coughing people are taken onto a bus as they are evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

11 / 12

Metro Station Smoke

Reynaldo Hernandez holds a cloth over his smoke covered face as he coughs deeply after being evacuated from a smoke filled metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) Reynaldo Hernandez holds a cloth over his smoke covered face as he coughs deeply after being evacuated from a smoke filled metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)

12 / 12

Metro Station Smoke

A firefighter sets up a triage area as people are evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin) A firefighter sets up a triage area as people are evacuated from a smoke filled Metro subway tunnel in Washington, Monday, Jan. 12, 2015. Metro officials say one of the busiest stations in downtown Washington has been evacuated because of smoke. Authorities say the source of the smoke is unknown. (AP Photo/Jacquelyn Martin)