Safety ·
CNESST details fatal roof-opening fall at Montreal-area site
By Workvado / Litequo LLC · Published · Updated
A findings release issued Oct. 22 describes how snow and an unsecured opening contributed to a worker’s fatal 8.7-metre fall in 2025.
Quebec’s workplace-safety commission published its investigation findings on Oct. 22 into a fatal fall at a construction site where Installation MB was working. The death occurred on Nov. 13, 2025; the new event is the release of the regulator’s findings, not a recent injury. CNESST says the worker fell 8.7 metres through an unsecured opening in the roof of a former boiler building. Pomerleau was the project’s general contractor, according to the commission.
The morning work involved preparing a protective floor over a glazed roof surface. Snow had accumulated, making the surface slippery. The worker and a supervisor were moving a plywood panel when the worker stepped backward onto rigid polyurethane insulation covering an opening of about 48 by 48 centimetres. The insulation gave way, and the worker fell to the concrete floor inside the building. CNESST says two openings were present in the lower roof. Concrete edges and insulation panels made them appear to be solid structural bases; snow further blended the surface. The plans used for the project did not identify an opening at the fall location.
The investigation says an inspection from inside the building could have revealed two square forms in the slab with different characteristics and allowed the team to determine their function before roof work began. The commission identified the fall through the opening and deficient management of the fall hazard as its two causes. That finding points to a coordination problem that can arise when temporary work begins on an existing building whose drawings do not match field conditions: crews may encounter concealed or undocumented openings after access and material handling are already underway.
CNESST states that where workers face a fall of more than three metres, employers must install guardrails; when that is impossible, they must use a suitable fall-protection measure in the prevention hierarchy and maintain it for the entire exposure. Openings must also be adequately secured. Its broader prevention process calls for identifying, analysing, correcting and controlling hazards. The agency plans to circulate the findings to employer and worker associations, relevant partners and the education ministry for use in affected schools.
For contractors, the useful operational implication is to treat roof preparation as a distinct hazard-control phase. Before moving plywood, glazing protection, insulation or other material across an unfamiliar roof, the supervisor can compare drawings with a physical inspection, check the underside where accessible, mark confirmed openings and establish a rated cover or guardrail that cannot be displaced by routine handling. Snow cover changes visibility, not the structural capacity of a cover. A patch of insulation or plywood should not be assumed to be a fall-protection system unless it has been assessed and secured for that purpose.
This case also shows why hazard communication has to reach every person entering the work zone. The employer, project coordinator and property owner may hold different pieces of building information; a pre-task briefing and documented walk-through can expose gaps before a crew starts moving materials. The commission’s public summary does not provide a detailed design review, identify the original purpose of the roof openings or describe all site procedures. Contractors should therefore use the findings as a prompt to verify their own site conditions and applicable rules, rather than infer that the exact sequence or remedy transfers unchanged to another project.
The report’s central lesson is concrete: a small, visually disguised roof opening can create a fatal fall path when snow and material handling obscure it. A written fall-protection plan is only effective when its controls are installed, maintained and understood at the point of work. On renovation and retrofit projects, contractors should make verification of roof openings part of mobilization and repeat it when weather or work sequencing changes what crews can see.
- Findings release
- October 22, 2026
- Incident date
- November 13, 2025
- Fall distance
- 8.7 m
- Roof opening
- Approximately 48 cm × 48 cm
Sources
- Décès d’un monteur vitrier d’Installation MB : la CNESST dévoile les conclusions de son enquête, CNESST, read October 27, 2026
- Investigation report EN004497, CNESST, read October 27, 2026
- Fall protection for falls over 3 metres, CNESST, read October 27, 2026