One worked died and two others were injured at Montreal renovation site in 2023
A fatal floor collapse at a Montreal‑Nord renovation site has prompted Quebec’s workplace safety regulator to issue a stark warning about demolition work carried out without proper planning, engineering oversight or worker training.
On Sept. 23, 2023, three workers under the authority of an individual identified only as “Monsieur A” were crushed when part of the ground-floor slab gave way during the demolition of two load‑bearing concrete block walls in the basement of a mixed‑use building on boulevard Rolland. One worker was killed on site. Two others sustained serious injuries, one to the lower body and the other to an arm.
The Commission des normes, de l’équité, de la santé et de la sécurité du travail (CNESST) concluded that the incident was driven by two core failures: the demolition of load‑bearing walls supporting precast hollow‑core concrete slabs, and deficient planning of the basement demolition work that exposed workers to crushing hazards.
Informal contractor, vulnerable crew
According to the investigation report, the building’s owner, 9387‑1853 Québec inc. (Chola Empire), was the maître d’œuvre on the construction site, with STS Construction & Rénovation contracted to rebuild the second and third floors after a 2022 fire. Basement demolition and cleanup were handed to “Monsieur A”, an unregistered individual contractor who typically did metal recovery and cleaning work, not construction or demolition.
On the day of the incident, five workers, all recruited by “Monsieur A”, arrived for debris removal, dismantling of partitions and mechanical systems, and general cleanup in the basement. Later that morning, at the request of the owner and/or the general contractor, he agreed to also demolish several concrete block walls that, unbeknownst to the crew, were load‑bearing.
Demolition proceeded using a rented jackhammer and hand tools. No temporary shoring was installed under the ground floor to support the hollow‑core slabs once the basement walls began to come down. The floor remained in place for part of the afternoon, until a critical failure in the slab joints triggered a widespread collapse over the work area.
In an engineering analysis appended to the report, a CNESST engineer writes that as the walls were demolished, “a failure mechanism develops inside the floor,” with the weight of the unsupported slabs transferred through joints that “are not designed to resist” those loads. When the shear and flexural capacity of those joints was exceeded, the floor failed.
Training, PPE and legal duties all missing
The human and organizational factors behind that structural failure are central to CNESST’s findings. None of the five workers held construction competency cards or had specific training in demolition. The investigation notes that the deceased worker and another seriously injured worker were recent immigrants, while a third injured worker was a temporary foreign worker on a closed permit that did not authorize construction work and did not name “Monsieur A” as employer.
Basic protections were also absent. The report states that workers were handling debris with bare hands and that “no worker was wearing gloves, goggles or a safety helmet,” while most lacked safety boots. None had completed the mandatory general construction safety course required by Quebec’s Code de sécurité pour les travaux de construction.
The report is sharply critical of both the maître d’œuvre and “Monsieur A” for failing to recognize their legal roles and obligations. The owner and “Monsieur A” “did not know their respective status as project owner and employer,” and investigators found that “no safe work procedure was developed or applied” and no prevention activities or safety management were in place on the site.
CNESST also underlines regulatory requirements that were ignored, including provisions that demolition of a pre‑stressed concrete slab must follow a procedure established by a qualified engineer, that no structural element likely to collapse may be left unprotected during demolition, and that all demolition work must be under the continuous supervision of a competent foreperson.
In the immediate aftermath, CNESST suspended all work at the site and barred access to the building, required an engineer’s attestation of structural integrity, and demanded a written procedure to secure the premises. Limited demolition and reconstruction were only allowed to resume after engineered shoring was installed and certified, and the ban on work on the upper floors remained in place.
To prevent similar incidents, the regulator is distributing its findings to construction associations, landlord organizations, and agencies working with immigrants and temporary foreign workers. The communiqué stresses that demolition of any building or part of a building “must be rigorously planned and executed,” and that owners and employers must involve an engineer or demolition expert to plan detailed work sequences and safe procedures.
For health and safety professionals, the case underscores a familiar risk profile: informal recruitment, vulnerable workers with little or no training, unclear employer/responsibilities, and structural work undertaken without engineering input or temporary support. The Montreal‑Nord collapse shows how quickly those ingredients can combine into a catastrophic—and preventable—fatality.
