SUPERVISOR SAFETY RESPONSIBILITIES UNDER ONTARIO'S OHSA

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If you supervise workers on a construction site in Ontario, the law holds you personally responsible for their safety. Not your company. You. The Occupational Health and Safety Act (OHSA) imposes specific duties on supervisors that carry real consequences — including personal fines and even jail time — when things go wrong.

Many supervisors do not fully understand the scope of their legal obligations. This article breaks down exactly what the OHSA requires, what happens when supervisors fall short, and how to protect yourself through due diligence.

Who Is a Supervisor Under the OHSA?

The OHSA defines a supervisor in section 1(1) as a person who has charge of a workplace or authority over a worker. That definition is deliberately broad. You do not need the word "supervisor" in your job title. If you direct, oversee, or have authority over other workers on a job site, the OHSA considers you a supervisor.

This includes:

• Foremen and site superintendents: The most obvious supervisors on a construction project.
• Lead hands and crew leaders: Even if your title is informal, if you are directing others' work, you are a supervisor under the Act.
• Project managers on site: When you are present on a construction project and exercising authority over workers, the OHSA's supervisor duties apply to you.
• Anyone temporarily in charge: If the regular supervisor leaves and puts you in charge — even for an afternoon — you are the supervisor for that period and you carry all the legal duties that come with it.

Courts have consistently interpreted the definition broadly. If you are exercising supervisory functions, you are a supervisor. The label on your hard hat does not matter.

Section 27: Your Legal Duties

Section 27 of the OHSA spells out the specific duties of a supervisor. Every one of these is a legal obligation, not a guideline. Failing to meet any of them can result in charges against you personally.

• Ensure workers use prescribed protective equipment (s. 27(1)(a)): You must make sure every worker under your supervision is wearing the required PPE — hard hat, safety boots, harness, high-vis, eye protection, whatever the work demands. If a worker is not wearing their harness and they fall, you are the one who will be asked why.
• Advise workers of hazards (s. 27(2)(a)): You are required to inform workers of any actual or potential hazards in the workplace that you are aware of. This is not about writing a generic hazard assessment once. It means communicating specific hazards to specific workers as conditions change throughout the day.
• Provide written instructions on measures and procedures (s. 27(2)(b)): Where required by regulation, you must give workers written instructions about safety measures and procedures to be followed. On construction projects, this includes fall protection plans, rescue plans, and confined space procedures.
• Take every precaution reasonable in the circumstances (s. 27(2)(c)): This is the catch-all duty, and it is the most powerful. Even if no specific regulation covers a particular hazard, you must still take every reasonable precaution to protect your workers. This duty has been used to prosecute supervisors in situations where no specific safety rule was broken but a foreseeable hazard was not addressed.

As a supervisor, "I didn't know" is not a defence. Section 27 of the OHSA holds you personally liable for ensuring workers follow the Act and regulations. If a worker is injured because you failed to enforce a safety requirement you knew about — or should have known about — you can face personal fines and even jail time.

Competent Supervision

The OHSA and Reg. 213/91 require that supervision on construction projects be "competent." Under the Act, a competent person is defined as someone who is qualified because of their knowledge, training, and experience to organize the work and is familiar with the OHSA, the regulations, and any hazards associated with the work.

In practice, this means:

• You must understand the work: You cannot supervise an activity you do not understand. If your crew is doing formwork at height and you have never been trained on fall protection systems, you are not a competent supervisor for that work.
• You must know the regulations: Saying "I did not know that was a requirement" is not a defence. Competent supervision means knowing what the law requires for the work being performed.
• You must be present and active: Competent supervision is not passive. Being on site but in a trailer while workers are doing dangerous work without oversight is not competent supervision. You must be actively ensuring compliance.

Required Training for Supervisors

Since July 1, 2014, all supervisors in Ontario are required to complete the Supervisor Health and Safety Awareness Training program. This is a mandatory requirement under Ontario Regulation 297/13 (for construction) and O. Reg. 297/13. The training covers the OHSA, the duties of workplace parties, workers' rights, and common hazards.

This training is available free of charge through the Ontario Ministry of Labour, Immigration, Training and Skills Development website. It takes approximately 3 to 4 hours to complete and results in a certificate of completion that must be kept on record.

In addition to the awareness training, construction supervisors must also hold any trade-specific certifications relevant to the work they oversee. If your crew is working at heights, you should hold a valid WAH certificate yourself. If they are handling hazardous materials, you need WHMIS training.

Personal Liability

This is the part that gets many supervisors' attention. Under the OHSA, a supervisor can be charged and convicted as an individual — separate from and in addition to any charges against the employer. Your company's legal department cannot shield you. Your employer's insurance does not cover your personal fines.

The maximum penalties for an individual convicted under the OHSA are:

• Fine: Up to $100,000 for a first offence. Additional convictions can carry higher fines.
• Imprisonment: Up to 12 months in jail.
• Both: A court can impose both a fine and imprisonment.

In cases where a worker is killed or critically injured and the supervisor's failure to meet their duties contributed to the incident, Criminal Code charges (criminal negligence causing death or bodily harm) are also possible under the Westray amendments (Bill C-45). These carry penalties of up to life imprisonment.

Real Prosecution Examples

Ontario courts prosecute supervisors regularly. These are not theoretical risks:

• Supervisor fined for fall protection failure: In multiple Ontario cases, supervisors have been personally fined $20,000 to $50,000 after workers fell from heights because fall protection was not in use. In these cases, the supervisor was on site and either knew or should have known that workers were not tied off.
• Supervisor charged after worker fatality: Following a fatal fall on a Toronto construction project, both the employer and the on-site supervisor were charged under the OHSA. The supervisor faced personal fines after the court found they failed to ensure fall protection was in use as required by Reg. 213/91, s. 26.
• Supervisor convicted for failing to advise of hazard: A supervisor was convicted for failing to inform workers about a known excavation hazard. The supervisor was aware of unstable soil conditions but did not communicate the risk or take steps to protect the workers in the trench.

In every one of these cases, the defence of "I told them to be safe" was not enough. The court looked at what the supervisor actually did — or failed to do — to ensure compliance.

The Due Diligence Defence

Due diligence is the primary defence available to supervisors charged under the OHSA. It means demonstrating that you took every precaution that was reasonable in the circumstances to prevent the violation or incident.

To establish due diligence, you generally need to show:

• You had a system in place: Written safety procedures, fall protection plans, toolbox talks, and documented hazard assessments show that you proactively addressed hazards — not just reacted after something went wrong.
• You actively enforced compliance: Having a rule is not enough. You must demonstrate that you regularly checked compliance, corrected non-compliance, and disciplined repeat offenders. If a worker was consistently not wearing their harness and you never addressed it, your due diligence defence collapses.
• You were trained and competent: Holding current certifications and having completed the mandatory Supervisor Health and Safety Awareness training demonstrates your commitment to understanding your responsibilities.
• You documented everything: Keep records of toolbox talks, safety inspections, training completions, corrective actions, and disciplinary measures. In court, if it is not documented, it did not happen.

Practical Steps to Protect Yourself

Knowing the law is the first step. Here is how to put it into practice every day:

• Start every shift with a safety talk: A five-minute toolbox talk that addresses the specific hazards of that day's work. Document who attended and what was discussed.
• Walk the site regularly: Do not stay in the trailer. Physically inspect the work areas, check that fall protection is in use, verify guardrails are in place, and confirm workers have the right PPE.
• Correct immediately: When you see a violation, address it on the spot. Document the conversation and any corrective action. If a worker repeatedly violates safety rules, escalate through your company's discipline process and document every step.
• Keep your own training current: Complete the Supervisor Health and Safety Awareness training if you have not already. Hold a valid WAH certificate. Take any additional training relevant to the work your crew performs.
• Know when to stop work: If conditions are unsafe and cannot be corrected immediately, stop the work. You have the authority and the obligation to do so. No schedule is worth a worker's life or your personal criminal liability.

The OHSA does not expect perfection. It expects that you took every reasonable precaution. Build safety into your daily routine, document what you do, and act on hazards immediately. That is what keeps your workers safe and keeps you on the right side of the law.