Five people were treated for smoke inhalation after an Orange Line train’s motor overheated during Wednesday evening’s commute at Back Bay Station, causing riders to panic and break windows to escape, officials and witnesses said.
Chris Herring said he was entering the station when he saw people trying to flee the area.
“I noticed a haze coming from the platform and got to the top of the stairs and people were running up,” Herring said in a direct message via Twitter. “[There was] thick smoke on platform. People had to get freed from the train.”
Herring said he then heard a popping sound, and Massachusetts Bay Transportation Authority workers asked everyone to evacuate.
In a statement, the T said the incident occurred just before 4:40 p.m., when the operations center “was called about a report of a propulsion issue on a northbound Orange Line train which had started to depart Back Bay Station which resulted in visible smoke to riders onboard.”
Two minutes later, “some passengers began to self evacuate and were assisted by Transit Officers and the motor person,” the statement said.
The doors on the subway remained closed because the train was moving away from the platform, officials said.
“Doors did not malfunction. The motor person had begun promptly opening doors to allow passengers to evacuate safely, away from (the) live third rail,” the statement said.
The agency addressed the issue of passengers’ chaotic exit from the train.
“Because no announcement had been made on the intercom, some passengers, understandably, began to self-evacuate through windows,” the statement said.
The Boston Fire Department evacuated the station at 4:57 p.m., the T said.
Online posts by people in the station showed a haze of smoke in the air. Many reported on social media that they were frightened. One said in a tweet that the station “filled with smoke” and people were “coughing like crazy.”
At the station, Stan Shen, 22, of Malden said he was on the train when the smoke appeared.
Some passengers had kicked out windows., he said. He exited after someone opened the door from the outside.
During the episode, he said, he saw “no flames, just smoke.”
T officials said five passengers were treated at the station for minor injuries and three were taken to a hospital. None of their injuries was life-threatening, said Transit Police Chief Kenneth Green.
Asked about accounts that passengers had broken windows to escape, Green said, “If people gotta get out, they gotta get out.”
Around 6 p.m., confusion continued to reign among some commuters, who entered the station only to find the Orange Line inaccessible.
“Now, a whole bunch of people are confused,” Meredith Westfall, 53, of Jamaica Plain said outside the station after learning she could not board the train.
The Boston Fire Department allowed Orange Line service to resume at 5:41 p.m. on the southbound side and 6:15 p.m. on the northbound side, the T said.
The T said it will investigate and reiterated that “passenger safety is the top priority” for the agency.
Steve Annear and Andy Rosen of the Globe Staff, and Correspondent Olivia Quintana contributed to this story. Travis Andersen can be reached at firstname.lastname@example.org