Ontario's Occupational Health and Safety Act (OHSA): What Every Employer Needs to Know

What Is the Occupational Health and Safety Act (OHSA)?

What the OHSA Is and What It Sets Out to Do

The OHSA is Ontario's primary legislation governing workplace health and safety. It establishes the minimum standards that employers, supervisors, and workers must meet to protect people from injury and illness on the job. The Act is built on a foundational concept known as the Internal Responsibility System (IRS): the idea that everyone in a workplace, from ownership to frontline workers, shares responsibility for health and safety.

The OHSA is administered and enforced by the MLITSD, which has broad authority to inspect workplaces, issue orders, and prosecute violations. Inspectors can enter any provincially regulated workplace at any time without advance notice.

Who the OHSA Applies To

Almost every worker, supervisor, employer, constructor, and equipment supplier operating in an Ontario provincially regulated workplace falls under the OHSA. The Act covers a wide range of industries and settings such as manufacturing facilities, construction projects, warehouses, and mining sites among them. Constructors and workplace owners carry specific OHSA duties on top of standard employer obligations, which is particularly relevant for organizations operating in construction and project-based industries.

The Two Exceptions That Catch Employers Off Guard

• Federally regulated employers are not covered. Banks, telecommunications companies, airlines, and interprovincial transport all fall under the Canada Labour Code, not the OHSA. If your organization operates in one of these spaces and also has an Ontario operation, you may have dual obligations under both federal and provincial regimes.
• The private residence exception. Work performed in a private residence by the owner or occupant is excluded from the OHSA. However, remote workers performing work in their own homes are covered under a recent legislative amendment. This distinction catches many employers off guard because if your employees work from home, your OHSA obligations follow them there.

How the OHSA Distributes Responsibility Across Your Organization

Employer Obligations Under the OHSA

Ontario law requires employers to take every reasonable precaution in the circumstances to protect workers. Courts and MLITSD inspectors interpret this broadly. A foreseeable hazard that went unaddressed is the employer's legal exposure. The general duty clause is not a vague aspiration, it is the legal standard against which your organization will be measured following any incident.

Core employer obligations under the OHSA include:

• Instruct, inform, and supervise workers to protect their health and safety.
• Appoint competent supervisors. The Act defines "competent" as qualified by knowledge, training, and experience, familiar with the relevant legislation, and aware of workplace hazards. Assigning a title without providing the underlying training does not meet this standard.
• Inform workers of known or foreseeable hazards before they are exposed to them, and train them on the safe handling of equipment, substances, and tools.
• Prepare and post a written OHS policy, reviewed annually, once 6 or more workers are regularly employed.
• Maintain a prevention program that implements the OHS policy in the specific context of the workplace.
• Share OHS report results with the JHSC or health and safety representative.
• Maintain washroom cleaning records, including the two most recent cleanings. This is a new requirement effective January 1, 2026, and it is already on MLITSD inspection checklists.

Each of these obligations becomes a point of legal exposure in the event of an incident. Compliance documentation is what separates a recoverable situation from a prosecutable one.

Supervisor Obligations and Personal Liability

Supervisors are personally liable under the OHSA. The legal and financial exposure does not stay at the corporate level, it follows the individual. This surprises many business owners who assume the company absorbs all risk.

Core supervisor duties include: ensuring workers use required protective devices and equipment; informing workers of hazards in the workplace; and taking every reasonable precaution for worker protection.

A supervisor who fails to comply with the OHSA can be fined up to $500,000 personally. That figure makes the business case for supervisor training straightforward.

Worker Obligations Under the OHSA

Workers are active participants in workplace safety under the law and not passive beneficiaries. They carry enforceable obligations:

• Comply with the Act and its regulations.
• Use or wear required protective devices and equipment as directed.
• Report missing or defective equipment to their employer or supervisor.
• Report any hazard or OHSA contravention they become aware of.
• Refrain from operating equipment or working in a manner that could endanger any worker.

The employer takeaway: when workers have been properly trained on their duties and that training is documented, it builds a layer of shared accountability that holds up under regulatory and legal scrutiny.

JHSC or Health and Safety Representative: What Your Business Is Required to Have

Workforce Thresholds and Required Structures

Ontario law ties the required internal health and safety structure to your workforce size. The table below outlines what is required at each threshold:

Workforce Size	What the Law Requires
1–5 workers	No JHSC or HSR required (unless a designated substance regulation applies)
6–19 regularly employed workers*	Health and Safety Representative (HSR) — selected by workers, not appointed by management
20–49 workers	Joint Health and Safety Committee (JHSC) — minimum 2 members: 1 worker rep, 1 management rep
50+ workers	JHSC — minimum 4 members; at least half must be non-management worker reps
300+ workers	Additional policy-level JHSC required
Construction projects (3+ months, 20+ workers)	JHSC required

*"Regularly employed" includes full-time, part-time, and seasonal workers expected to work for 3 or more months. If your organization is growing quickly, build the required structure before you cross the threshold. Inspectors look at worker counts, not stated hiring intentions.

JHSC Structure, Powers, and Certification Requirements

The JHSC is a documented internal mechanism for identifying hazards, investigating incidents, and demonstrating due diligence. When functioning properly, it is an operational asset, an early-warning system that surfaces risk before it materializes into an incident.

Core JHSC powers and functions include:

• Identifying workplace hazards through regular inspections and worker input.
• Conducting monthly workplace inspections by a designated member on a rotating basis.
• Investigating critical injuries and work refusals.
• Making written recommendations to the employer, who must respond in writing within 21 days.
• For certified members only: issuing a stop-work direction in conditions that present an immediate danger to workers.

There is a certification requirement that At least 2 JHSC members must complete Ministry-approved Part 1 (3-day) and sector-specific Part 2 training. Certification obtained after March 2016 expires every 3 years and requires a 1-day refresher. Running an uncertified committee is a compliance gap that inspectors will identify.

Remember to post JHSC member names and work locations visibly in the workplace because this is one of the first things an inspector checks and hold meetings at minimum every 3 months, in person or virtually. Minutes must be kept and made available.

Health and Safety Representative: Role, Selection, and Training

A Health and Safety Representative (HSR) is required for workplaces with 6 to 19 regularly employed workers. The HSR must be selected by non-management workers since the employer cannot appoint the HSR. This is a common compliance error in smaller operations.

The HSR holds most of the same investigative and advisory powers as a JHSC: conducting workplace inspections, identifying hazards, and making recommendations to the employer. The key distinction is that an HSR cannot independently issue a stop-work direction.

A one-day foundational training course is available and gets the HSR operationally ready quickly. Low time investment, significant compliance value. The employer is legally required to cooperate with the HSR. Failure to do so is a direct violation of the Act.

Required Policies, Programs, and Training Records Under the OHSA

OHS Policy and Prevention Program

Ontario employers with 6 or more regularly employed workers must maintain a written OHS policy, reviewed annually, signed, and posted visibly in the workplace.

The prevention program is the policy's operational counterpart. The policy states the employer's commitment to health and safety; the program documents how that commitment is implemented in your specific workplace (hazard controls, emergency procedures, inspection schedules, and assigned responsibilities). There is no universal template because it must reflect your actual operation.

Ontario's free Safety Plan Builder tool can help smaller employers build a customized program without starting from scratch. At 5 or more employees, all health and safety policies, including the OHS, violence, and harassment policies, must be posted or made available in a readily accessible electronic format, such as a dedicated intranet page workers are directed to.

Workplace Violence and Harassment Policies

All Ontario employers, regardless of size, must have both a workplace violence policy and a workplace harassment policy. This is one of the most common OHSA compliance gaps across all business sizes. Both policies must be reviewed at least annually. At 6 or more workers, both must be in writing and posted visibly in the workplace.

The workplace violence program must include: a risk assessment specific to the employer's workplace type, layout, and work conditions; controls based on that assessment; a protocol for workers to summon immediate assistance when needed; and a process for reporting and investigating incidents. Risk assessment results must be shared with the JHSC or HSR.

The workplace harassment program must include: a reporting process with an alternate path if the alleged harasser is the employer or supervisor; investigation procedures with assigned responsibility; confidentiality provisions; and a written process for communicating findings and corrective actions to both parties involved. A sample workplace harassment policy is available on the MLITSD website and can be adapted for most workplaces quickly.

Having policies on paper is not compliance by itself. Workers and supervisors must be trained on the content. An inspector will ask for evidence of that training.

Mandatory Training Requirements

In Ontario, if you cannot demonstrate that training happened, it is treated as though it did not happen. Training records are not administrative overhead, they are your legal defense.

Required training at a glance:

• Worker Health and Safety Awareness Training: all workers must complete the 1-hour eCourse (O. Reg. 297/13, in force since July 1, 2014).
• Supervisor Health and Safety Awareness Training: all supervisors must complete their own separate 1-hour eCourse.
• JHSC Certification (Part 1 and sector-specific Part 2): mandatory for at least 2 JHSC members, through a Ministry-approved trainer; refresher required every 3 years.
• Working at Heights: required before any worker uses fall protection on a construction project.
• Sector and Hazard-Specific Training: required by applicable regulations, for example, WHMIS for any workplace handling controlled products, or noise awareness training where O. Reg. 381/15 applies.

Employers must keep training records and make them available to workers within 6 months of their leaving employment. Missing training records are among the most common triggers for Ministry of Labour compliance orders, and the easiest compliance gap to close proactively.

Worker Rights Under the OHSA and What They Mean for Your Operation

Right to Know: Hazard Information, Training, and Protective Equipment

Workers have a legal right to know about every hazard they face: physical, chemical, biological, ergonomic, and psychosocial. The operational implication is direct: onboarding a worker into a hazardous role without first training them on those specific hazards is not an oversight, it is an OHSA violation.

Practically, this means that safety data sheets (SDS) must be accessible for any controlled product; safe work procedures must be documented and communicated; and protective devices must be provided and demonstrated, not simply handed over. WHMIS requirements tie directly into this right for any facility handling chemicals or hazardous materials.

Proper hazard communication is also the employer's first line of legal defense in the event of an incident.

Right to Participate: Committees, Representatives, and Safety Concerns

Workers have the right to help identify and resolve health and safety concerns. Their formal channel is the JHSC or HSR, but any worker can raise a concern informally at any time. Workers who identify a hazard or OHSA contravention have a statutory duty to report it to their employer or supervisor. When workplace culture supports this, it functions as an internal early-warning system.

JHSC worker members have the right to accompany Ministry inspectors during workplace visits. Ensure your JHSC members are aware of this and prepared to engage professionally when it occurs. The employer must respond in writing to JHSC recommendations within 21 days since non-response is itself a violation.

Right to Refuse Unsafe Work: The Process and the Employer's Obligations

The right to refuse unsafe work is the provision that most frequently creates operational disruption when employers do not know the process. The refusal itself is not the problem. Mishandling the process is.

A worker can refuse work when they have reasonable grounds to believe that equipment, physical conditions, or the risk of workplace violence is likely to endanger themselves or another worker. The process unfolds in two stages:

Stage 1 — Internal Resolution

1. The worker notifies the employer or supervisor of the refusal and the stated reason.
2. The worker remains in a safe place nearby and stays available (this time is paid).
3. The employer or supervisor investigates in the presence of the worker and the HSR or JHSC worker member.
4. If the concern is resolved to the worker's satisfaction: the worker returns to work.

Stage 2 — If Stage 1 Does Not Resolve the Issue

1. The worker continues to refuse; either party may contact MLITSD at 1-877-202-0008.
2. A Ministry inspector investigates in the presence of the worker, a management representative, and the HSR or JHSC worker member.
3. The inspector issues a written decision; if modifications are ordered, the worker returns to work.

Two errors that significantly compound the situation:

• Reassigning refused work to another worker without first informing that worker, in writing and in the presence of the HSR or JHSC member, that the work was refused and the reason why. This is a direct violation.
• Disciplining, threatening, or penalizing the worker for refusing. This constitutes an unlawful reprisal under Section 50 of the OHSA and opens the employer to a separate formal complaint.

Note: certain healthcare workers and teachers have a more limited right to refuse when doing so would directly endanger another person's life or safety.

Hazard Management, Incident Reporting, and Sector-Specific Regulations

Hazard Identification and Control Obligations

Employers have a proactive duty to identify and control hazards, not a reactive one. The hierarchy of controls applies: engineering controls first (redesigning the process, enclosing the hazard, substituting the material), followed by administrative controls (safe work procedures, job rotation, scheduling), with personal protective equipment (PPE) as the last resort, never the default response.

If a known hazard exists in a facility and the only control in place is distributing PPE, the employer is not in compliance and carries significant exposure in the event of an incident. Workers and supervisors must be informed about hazards before exposure, JHSC and HSR must receive OHS report results, and reports of defective or missing protective equipment must be acted on, documented, and tracked to close-out.

Critical Injury and Fatality Reporting Requirements

Certain incidents require immediate notification to the Ministry:

• Critical injuries as defined under Regulation 834: fractures, amputations, loss of sight, severe burns, internal hemorrhaging, unconsciousness.
• Explosions, fires, or floods that caused or had the potential to cause bodily harm.
• Fatalities.

After notification: do not disturb the scene except to assist the injured worker or prevent further injury. Disturbing the scene before an inspector clears it is a separate violation. Notify the JHSC or HSR as well. The Ministry's 24/7 line (1-877-202-0008) should be posted visibly in the workplace before an incident occurs.

Noise Regulation (O. Reg. 381/15): What It Adds for Industrial and Construction Employers

Ontario's noise regulation is a concrete example of how OHSA regulations layer sector-specific obligations on top of the Act's general duties. O. Reg. 381/15 applies to all OHSA-covered workplaces and sets a maximum occupational noise exposure limit of 85 dBA (Lex,8).

This is not a single snapshot reading, it is the average noise dose a worker absorbs across a full 8-hour shift. A machine that runs at 95 dBA for two hours in an otherwise quiet environment still produces a measurable daily dose that factors into compliance. That distinction is what the regulation is built around, and it is the concept employers in loud industries need to understand before the number means anything actionable.

Ontario's 85 dBA limit is actually more protective than the federal 87 dBA standard. When noise levels at a facility are likely to exceed that threshold, providing hearing protection alone is not sufficient. The hierarchy of controls applies here as well: engineering controls first (quieter equipment, acoustic enclosures, source isolation) then work practice controls, with hearing protection devices as the last resort.

When noise exposure cannot be eliminated, a hearing conservation program is required. It must include audiometric testing (baseline testing on hire, and periodic testing thereafter), provision and maintenance of hearing protection, and a written program. Audiometric records must be retained for the duration of employment plus 10 years. Employers must conduct noise assessments, train workers on hearing protection selection and use, and maintain records of all of the above.

This regulation is particularly relevant in construction, aggregate, mining, and manufacturing environments, where MLITSD has run targeted enforcement campaigns. If the operation is consistently loud, this regulation is on the inspector's checklist.

OHSA Enforcement, Inspections, and the Cost of Non-Compliance in Ontario

How MLITSD Inspections Work

MLITSD inspectors have broad authority: they can enter any provincially regulated workplace at any time without advance notice, inspect all areas, review all records and documents, interview any worker or supervisor privately, and order tests or assessments at the employer's expense.

Inspections are triggered by worker complaints (which can be filed anonymously), reported critical injuries or fatalities, work refusals, proactive Ministry sector enforcement campaigns, or random proactive visits.
When a violation is found, the inspector issues a compliance order specifying what must be corrected and by when. After the fix, the employer submits a notice of compliance and must post the order visibly in the workplace for 14 days.

2025 update: Ontario introduced Administrative Monetary Penalties (AMPs). Inspectors can now issue financial penalties directly on the spot, without requiring court prosecution. The gap between a compliance failure and a financial consequence has shortened significantly. Beyond the direct fine, a Ministry investigation triggers scene preservation (production stops), legal costs, worker downtime, and potential WSIB premium consequences. The total business impact of a serious incident is substantially larger than the fine itself.

Ontario's OHSA Penalty Structure

Ontario's penalty structure is the highest in Canada. The table below frames the exposure at each level of the organization:

Who	Maximum Fine Per Offence	Imprisonment
Corporations	$2,000,000 (as of October 2023, highest in Canada)	N/A
Directors and officers of corporations	$1,500,000	Up to 12 months
Individual employers and supervisors	$500,000	Up to 12 months

Repeat corporate offenders should be aware that a second or subsequent conviction involving worker death or serious injury within a 2-year period triggers a mandatory minimum $500,000 fine. There is no judicial discretion below that floor.

These figures apply per offence. A single incident can produce multiple charges. The cumulative exposure can be significant even for mid-sized operations. The Ministry does not reserve prosecution for large corporations but small business owners and individual supervisors have been fined, and some have served custodial sentences.

The employers who hold up best under scrutiny are those where every level of the organization, from ownership to frontline supervision, understands and acts on their responsibilities under the Act.

The Rules Are Clear. The Next Step Is Yours.

You now have a working map of Ontario's OHSA: who it covers, what it requires, and what it costs to ignore. The question is where to focus first. Here are the six compliance actions that deliver the highest impact relative to effort:

• Confirm that your JHSC or HSR structure matches your current headcount, and verify that required certifications are current and not approaching expiry.
• Put your workplace violence and harassment policies in writing, post them visibly, and train your team on the content (all staff, not just supervisors).
• Close your training gaps and build the habit of maintaining records: worker awareness, supervisor awareness, and JHSC certification are the three most commonly missing.
• Run a genuine hazard assessment of your operation and verify that your controls go beyond PPE distribution. The hierarchy of controls is the legal standard.
• Document your critical incident response process before it is needed: who calls the Ministry, who preserves the scene, who notifies the JHSC, and where the 24/7 line is posted.
• Understand the current penalty structure and reflect it in how your organization treats compliance investment. A $2,000,000 corporate fine reframes the cost of doing nothing.

For industrial, construction, and manufacturing employers, one area that frequently produces compliance gaps is noise and vibration monitoring under O. Reg. 381/15. Soft dB specializes in helping operations teams move from uncertainty about their noise exposure levels to documented assessments, defensible controls records, and a written hearing conservation program that holds up when an MOL inspector walks in. If getting your facility under the 85 dBA threshold with a paper trail to prove it is on your list, that is the conversation to have.

Request a quote from Soft dB and find out what your facility's noise compliance picture actually looks like.

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This document is for informational purposes. Regulatory requirements should be verified against current official sources.