The story unfolds between 2012 and 2014, when the Ministère des Transports du Québec ("Ministry") entered into a contract with Couillard Construction Limited ("Couillard") for the extension of Highway A-5 in Outaouais. Couillard, as general contractor, subcontracts with Dyfotech Inc. ("Dyfotech") to excavate the rock, which it will do by drilling and blasting.
Unfortunately, the blasting works contaminated the artesian wells of several local residents and they had to be provided with bottled water, which the Ministry undertook to do.
Who is liable for this situation? The Ministry, Couillard or Dyfotech?
To answer this question, we need to examine the facts in a little more detail as well as the positions of the parties.
What is important to remember is that the Ministry held Couillard responsible for the actions of Dyfotech.
On the other hand, Couillard held the Ministry liable for the harm suffered by the residents because the Ministry was allegedly in possession of information about the specific risks posed by ammonium nitrate and sodium perchlorate contained in some of the explosives, which leaked into the water table and contaminated the artesian wells in the area.
The General Conditions
The Ministry's then current 2011 General Conditions did not prohibit the use of explosives containing perchlorates (This has changed, and is now prohibited as of 2015). And, crucially, there were environmental reports produced prior to the start of the works that should have alerted the Ministry to the specific risks of contamination of artesian wells in the area.
The Environmental Reports
A first report, dated 2009, came from the Ministry's geotechnical department and recommended that precautions be taken during blasting works near the wells. A second report, completed in 2010, recommended that certain wells deemed to be at risk be subject to environmental monitoring, particularly with respect to nitrites and nitrates.
A third report was prepared by the federal authorities since the project was to take place in part in the National Capital Region of Canada. This report, produced by Transport Canada, contained a review of the environmental impacts of the project. Already, an analysis of water from several wells revealed that several water potability criteria were not met and that rock cuts could increase the risk of water contamination.
These reports were not shared with the general contractor.
The Client's Duty to Inform or Advise the General Contractor
Should the Ministry have shared these reports with the general contractor, and by extension with the subcontractor? The Superior Court answered yes.1 It reviewed the concept of the principal's duty to inform or inquire, a principle recognized in the Supreme Court of Canada's decision in Bank of Montreal v. Bail Ltée2, and summarized the principles as follows:
 This duty to inform arises from the duty of good faith set out in articles 7 and 1375 C.C.Q. and generally covers the following obligations:
a) not to mislead his co-contractor;
b) Not to provide false information;
c) not to provide ambiguous or contradictory information; and
d) Not to provide incomplete information.
The Superior Court concluded that it was incumbent upon the Ministry to be more transparent in its bidding documents by describing with sufficient care and precision the issues already identified to allow prospective bidders to know exactly what was expected of them.
The Attorney General's action against Couillard was therefore dismissed and the Court granted in part Couillard's counterclaim against the Attorney General.
There was no appeal.
1. Couillard Construction limitée c. Procureur général du Québec, 2023 QCCS 252
2. 1992 CanLII 71 (SCC),  2 SCR 554
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