MONTREAL - The Quebec government is preparing to sue several engineering companies for $3.4 million over a tunnel collapse last year.

The three engineering firms — CIMA+, Dessau and SNC-Lavalin — have received a lawyer's letter from the provincial government demanding that sum.

Those companies were involved in renovations to the Viger Tunnel, which saw a 25-tonne concrete beam collapse. While the busy downtown tunnel is generally filled with traffic the accident occurred on a weekend morning and nobody was hurt.

The government had announced plans several months ago to seek compensation. Its legal letter was sent last week, on July 27.

The provincial Transport Department says mistakes were committed by those companies and it wants to be refunded for the repair costs.

The July 2011 collapse came amid a wave of problems in Quebec's road network and prompted a renewed debate on infrastructure policy.

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