Executive Summary: Key Legal and Evidentiary Issues

• Employer was accused of failing to shore trench walls on a construction site in accordance with safety regulations.

• CNESST inspector relied solely on visual observations and photos, without precise measurements of slope angles.

• Employer claimed exemption from shoring requirement due to trench slopes being less than 45° from 1.2 m above the bottom.

• Discrepancy in credibility and reliability of testimony between CNESST inspector and employer's foreman influenced the court’s findings.

• Reports from engineers supported the safety and conformity of the excavation method used.

• Court found no danger of landslide and accepted the employer’s evidence as satisfying the legal exception to the shoring rule.

Facts and procedural background

On March 7, 2023, a CNESST inspector, Paul Dupont, visited a construction site in Montréal, part of the "Les cours Pointe-St-Charles" project. The site was operated by Excavation J.P.M. 2012 Inc. During the inspection, the inspector observed a trench with a worker nearby and noted that the trench walls lacked shoring materials, which he believed posed a risk of collapse. Based on his visual evaluation of the trench slope angles, Mr. Dupont ordered an immediate halt to the work.

The trench included a northern wall with multiple slope angles, some of which appeared near-vertical and not supported. The inspector did not use any measurement tools, instead relying on his experience to judge the compliance of the slopes. The company foreman, Steve Hamelin, explained that the excavation was in progress and no workers were yet inside the trench. He stated that an engineer had verbally approved the method used—1.2 meters vertical at 90° followed by a slope of 45°—and a written attestation followed the next day.

The CNESST prosecuted the employer for failing to shore the trench walls per article 3.15.3 of the Code de sécurité pour les travaux de construction. The employer claimed an exemption under the same provision, arguing the trench slope was below 45° from less than 1.2 m above the bottom and posed no landslide risk.

Tribunal's assessment and findings

The Tribunal focused on two key issues: whether the trench slope met the required angle to qualify for exemption and whether there was any actual risk of a landslide. It reviewed photographs submitted by both parties. The Tribunal found the CNESST’s images unreliable due to visual distortion, while the employer’s photographs, which included measured angles (22.5°, 32.8°, and 38.4°), were credible and clear.

Credibility played a major role. The Tribunal viewed Mr. Hamelin’s testimony as candid and consistent, while Mr. Dupont’s responses during cross-examination were evasive and affected his reliability. The court emphasized that while the legal burden to prove compliance lies with the employer, the CNESST's failure to use simple measurement tools weakened its case.

Two reports—one geotechnical and one from an engineer—were admitted as physical evidence. Although not treated as expert evidence, they supported the employer’s position that the chosen method was safe. The Tribunal concluded that the excavation method used complied with both the Code and the LSST, and that the trench did not present a danger of collapse.

Final outcome

The Tribunal found that Excavation J.P.M. 2012 Inc. had demonstrated, on the balance of probabilities, that the trench slopes were less than 45° starting from less than 1.2 m above the bottom and posed no risk of landslide. As a result, the company met the exception to the shoring requirement, and the court acquitted the employer of the infraction.