Montreal's regional transit agency says it will fix more than a dozen cracks that have opened up in the Laval metro tunnels, but assured passengers that the fissures are not a danger.

Jean-Pierre Normand, a project manager at the metropolitan transport agency, told CTV's Catherine Sheriffs that concrete will be injected into the cracks within six months.

The AMT confirmed Monday that at least 17 cracks have opened up in the tunnels of the new metro network. Found in the Henri Bourassa and de la Concorde stations, all are more than six feet long and about one millimetre wide.

"We're talking about fine cracks. We're talking about one millimeter width, so there's nothing to worry about as far as structural soundness is concerned," said Normand.

2007 recommendations

The cracks have not been repaired despite an engineer's recommendation back in November 2007, just seven months after the Laval network opened to the public. The AMT has so far spent $750,000 on repairing cracks to the Laval metro system.

Engineer Frederic Legeron of the firm Tecsult submitted a written note that said the cracks needed to be repaired to ensure the long-term stability of the tunnels, one of which runs under Riviere-des-Prairies.

Cracks were expected

The AMT agrees with the assessment, but said that 14 other engineers examined the tunnels and concluded that the cracks are due to normal shrinkage and are not dangerous.

Structural engineer Hellen Christodoulou agrees.

"With concrete you always have shrinkage, cracks, and some hairline cracks are quite often normal," she said.

The AMT said it expected the cracks due to water evaporation and fluctuating temperatures, and included a clause in the construction contract requiring the builders to repair cracks when they occurred.

The concern, said Christodoulou, is why it's been left untouched for two years.

"These questions should not be, and it's a matter of our system, I think, failing the public," she said.

The AMT owns the Laval metro system and is currently negotiating with the Montreal Transit Corporation to complete a transfer of ownership.