Three workers were trapped in Ottawa's light rail transit tunnel near Waller Street and Laurier Avenue on Thursday after some concrete came loose and fell.

The three workers were in a 'safe zone' about 200 metres from the tunnel's entrance for about an hour. One suffered minor injuries and was taken to hospital; the others were unharmed.

While police initially called the incident a "tunnel collapse," Mayor Jim Watson later said at the scene that it was not a tunnel collapse; rather, workers were spraying concrete in a part of the tunnel and some rebar came loose and fell down.

In a statement, city transportation chief John Manconi said some reinforcing steel came loose when workers were applying concrete to the wall of the tunnel. The steel was resting on the workers' lift, so they needed help lowering it safely.


The Ministry of Labour has been called in to investigate; they were due on site around 7:30 p.m. There will be no work in the tunnel until the ministry gives the all-clear.

Ottawa Fire Services said just before 5:30 p.m. that the three workers had emerged from the tunnel and one had minor injuries.

Emergency crews rushed to the scene near the University of Ottawa around 4:30 p.m. on Thursday, Nov. 10, 2016. More than 30 vehicles flooded to the scene, including fire, police, paramedic and Hazmat crews.

The site where emergency crews gathered is near the spot that an eight-metre-wide sinkhole opened up when the road collapsed in Feb. 2014. A city study showed that collapse was likely due to LRT construction.

However, Manconi said the incident "did not occur near the sink hole."

The road was closed for emergency personnel response. The road has been reopened to all traffic.

Laurier Avenue was closed from Nicholas to King Edward Thursday afternoon. It reopened shortly after 6 p.m.