Who is responsible: owners, prime contractors, employers, supervisors and workers

On a Monday morning in March, a drywall worker employed by Pinecrest Interiors Ltd. stepped backwards off the edge of an unguarded floor opening on level 5 of Cottonwood Place and fell 3.4 m (11 ft) to the floor below. He broke his wrist and two ribs. The opening had been cut for a mechanical shaft the previous Friday by Keystone Mechanical Ltd.. The guardrail around it had been removed by a Highline Scaffold Ltd. crew moving material on Saturday and never put back. The drywall foreman had not walked the floor before sending his crew up, and nobody from Tallgrass had been on level 5 since Thursday.

Four employers had a hand in that opening. When the a safety and health officer from the Branch arrived that afternoon, the first question was not 'whose worker fell?' but 'who was responsible for the hazard, and what did each of them do about it?' This course is about the answer to that question on a construction project: the legal duties of each party, and the safety program a general contractor builds to meet them.

Earlier courses in this track followed the hazards themselves: site organization in HSE-370, concrete and masonry in HSE-371, demolition in HSE-372, traffic control in HSE-373 and steel erection in HSE-374. CON-355 looks at safety leadership from the supervisor's chair. HSE-375 steps back and looks at the legal frame that holds all of that together, and at how Tallgrass turns those duties into a working program on Cottonwood Place.

A construction site is a shared workplace

A factory usually has one employer, one set of managers and one safety program. A construction site is different. At the peak of Cottonwood Place, about 140 workers from 18 different employers were on site on a typical day: Tallgrass's own carpenters and labourers, the excavation and shoring crew, the formwork, rebar and concrete trades, electricians, plumbers and sheet metal workers, the elevator installers, the roofers, the glaziers, the drywallers and painters, plus delivery drivers, inspectors and the owner's representatives. Each employer brings its own supervisors and its own way of working, and their work overlaps in space and time. A hazard created by one trade, like the shaft opening, often injures a worker from another.

The law deals with this in two ways. It gives every party a duty for the things it controls, and it puts one party in charge of coordinating everyone. The details differ between Manitoba and the United States, but the logic is the same.

The legal frame in Manitoba

In Manitoba, the main law is The Workplace Safety and Health Act, together with the Workplace Safety and Health Regulation (Man. Reg. 217/2006). The Act sets out general duties for employers, workers, supervisors, owners, contractors, prime contractors, suppliers and self-employed persons. The regulation sets out the detailed technical rules: fall protection, excavations, cranes, scaffolds, hazardous substances and so on. The Workplace Safety and Health Branch of the provincial government enforces both. Workers compensation is a separate system, run by the Workers Compensation Board of Manitoba (WCB), and its prevention arm, SAFE Work Manitoba, promotes safety programs and certification. Manitoba amended the Act in 2025, adding psychological safety to its objectives, requiring a competent person to carry out required risk assessments, and requiring improvement and stop work orders to be posted for at least seven days.

The owner

The owner of Cottonwood Place is Cottonwood Place Developments Ltd.. Under section 7.2 of the Act, an owner must ensure, so far as is reasonably practicable, that the land and premises it controls are provided and maintained without risk to anyone's safety and health, must cooperate with others who have duties under the Act, and must comply with the Act and regulations. In practice the owner's most important duties come before construction starts: telling the contractor about hazards it knows of on the site, such as buried services, contaminated soil or asbestos in an existing building, and choosing a competent contractor. Under section 7 of the Act, the owner is also the prime contractor unless it contracts with someone else to take on that role, which is what Cottonwood Place Developments did with Tallgrass.

The prime contractor

Under section 7(1) of the Act, a construction project site where more than one employer or self-employed person works at the same time must have a prime contractor. The prime contractor is the person who contracts with the owner to be prime contractor; if there is no such contract, the owner is the prime contractor (section 7(2)). Tallgrass's contract with Cottonwood Place Developments names it as prime contractor for the whole site from mobilization to handover. Under section 7(3), the prime contractor must ensure, so far as is reasonably practicable, that every person working on the project complies with the Act and the regulations; must coordinate, organize and oversee the work at the site and conduct its own activities so that no person is exposed to risks; must cooperate with others who have duties under the Act; and must comply with the Act and regulations itself. Under section 7.4(8), where two or more employers with safety and health programs are on the site, the prime contractor must coordinate those programs.

Either way, the general contractor does not become responsible for every act of every subcontractor. It is responsible for running the site so that hazards are found and fixed, for coordinating trades whose work affects each other, and for acting when it sees or should see a problem. On level 5, that meant Tallgrass should have had a way to know that an opening had been cut and that its guardrail had come off.

Employers

Every employer on site keeps its full duties to its own workers. Under section 4 of the Act, an employer must ensure, so far as is reasonably practicable, the safety, health and welfare of all its workers: providing safe equipment and systems of work, information, instruction, training and supervision, competent supervisors, and the protective equipment the regulation requires. Employers with 20 or more regularly employed workers at a workplace must have a written workplace safety and health program (section 7.4(1)). Under section 7.1, a contractor that directs the activities of workers of other employers also has duties for those workers.

On level 5, Pinecrest Interiors Ltd. was the exposing employer. Keystone Mechanical Ltd. created the opening and Highline Scaffold Ltd. removed the guardrail. Each owed duties to its own workers and, under the general duties, to anyone affected by its work.

Supervisors

Manitoba's Act gives supervisors their own duties in section 4.1. A supervisor must, so far as is reasonably practicable, take all precautions necessary to protect the safety and health of the workers under their supervision, ensure that those workers comply with the Act and regulations, use and wear required protective equipment themselves, advise workers of all known or reasonably foreseeable risks in the area where they work, cooperate with others who have duties under the Act, and comply with the Act and regulations. A supervisor is any person who has charge of a workplace or authority over a worker: foremen and lead hands count, whatever their job title.

Jordan Pike, the Pinecrest foreman, had sent his crew to level 5 without walking the floor first. That was a supervision failure, whatever else had gone wrong.

Workers

Workers have duties too. Under section 5 of the Act, a worker must take reasonable care to protect their own safety and health and that of others affected by their acts, use the protective equipment and devices required, cooperate with their employer and supervisor, and comply with the Act and regulations. Workers also have three rights that run through Canadian safety law: the right to know about hazards, the right to participate (through committees and representatives) and the right to refuse dangerous work. The 2025 amendments define dangerous work as an imminent risk of serious physical or health injury from a hazard where reasonable controls are not in place.

Self-employed workers and others on site

Self-employed persons on a construction site, such as an independent tile setter, must under the Act protect themselves and others affected by their work and comply with the regulation, and they fall under the prime contractor's coordination. Suppliers must provide equipment that is safe when used as directed, with the information needed to use it safely. Visitors, inspectors and delivery drivers are not workers of Tallgrass, but Tallgrass must still conduct its activities so they are not exposed to risk.

Overlapping duties are the point

Students sometimes ask who is really responsible for a hazard like the open shaft. The honest answer is that several parties were, at once, and that this is deliberate. Overlapping duties mean that if one layer of protection fails, another should catch the problem. The scaffold crew should have replaced the guardrail. The mechanical contractor should have checked its opening before leaving on Friday. Tallgrass should have had a system for openings and a walk of each active floor at the start of each shift. The drywall foreman should have walked the floor. The drywall worker should have looked behind him. Any one of those would have prevented the fall.

Counting how many layers failed

After the incident, Owen Hartley used a short script with the investigation team to list each party's expected control and whether it worked. Seeing all five failures in one place made the point that this was not one person's mistake.

# Layers of protection around the level 5 shaft opening.
layers = [
    ("Mechanical contractor", "check opening guarded before leaving", False),
    ("Scaffold contractor", "replace any guardrail it removes", False),
    ("General contractor", "opening register and daily floor walk", False),
    ("Drywall foreman", "walk the floor before sending the crew", False),
    ("Drywall worker", "look before stepping back", False),
]
failed = [name for name, control, worked in layers if not worked]
print(f"{len(failed)} of {len(layers)} layers failed")
for name, control, worked in layers:
    print(f"- {name}: {control} -> {'worked' if worked else 'FAILED'}")
print("Any single working layer would have prevented the fall.")

5 of 5 layers failed
- Mechanical contractor: check opening guarded before leaving -> FAILED
- Scaffold contractor: replace any guardrail it removes -> FAILED
- General contractor: opening register and daily floor walk -> FAILED
- Drywall foreman: walk the floor before sending the crew -> FAILED
- Drywall worker: look before stepping back -> FAILED
Any single working layer would have prevented the fall.