Ontario Critical Injury & Incident Reporting Tool

TL;DR

In Ontario, an injury is a critical injury under O. Reg. 420/21 if it places life in jeopardy, produces unconsciousness, causes substantial blood loss, fractures a leg or arm (not a finger or toe), amputates a leg, arm, hand or foot, burns a major portion of the body, or causes loss of sight in an eye. A critical injury or a workplace death must be reported to the Ministry of Labour immediately by phone at 1-877-202-0008 (24/7) under OHSA s. 51(1); the scene must be preserved under s. 51(2); a written report goes to a Director within 48 hours (contents prescribed by O. Reg. 420/21 s. 3); and WSIB Form 7 is filed within 3 business days. A disabling but non-critical injury is a 4-day written notice under s. 52(1).

Critical Injury Reporting in Ontario — What the Supervisor Needs to Know Right Now

You have been on site when the radio goes quiet and then someone starts yelling. The next sixty minutes determine whether your company gets through this by the book or spends the next two years in MOL enforcement. This is the reporting landscape from someone who has stood in that circle of hard hats waiting for the inspector.

What counts as a critical injury in Ontario? The seven O. Reg. 420/21 criteria

Ontario Regulation 420/21 under the Occupational Health and Safety Act — in force July 1, 2021, and the regulation that revoked the old R.R.O. 1990 Reg. 834 — defines "critical injury" as an injury of a serious nature that meets any one of seven conditions. The list is short and absolute — there is no room for interpretation. A critical injury is one that: (1) places life in jeopardy, (2) produces unconsciousness, (3) results in substantial loss of blood, (4) involves the fracture of a leg or arm but not a finger or toe, (5) involves the amputation of a leg, arm, hand, or foot, (6) consists of burns to a major portion of the body, or (7) causes the loss of sight in an eye. Notice what is not on the list. A broken finger is not a critical injury. A laceration that bleeds but does not produce "substantial" blood loss is not critical. A concussion where the worker never loses consciousness may not be critical — though if life is in jeopardy it still qualifies under criterion one. When you are standing on site trying to make the call, the safe move is always to report. You cannot get in trouble for over-reporting. You can absolutely get in trouble for under-reporting. If any one of the seven applies, the injury is critical and OHSA section 51 kicks in immediately.

Who do you have to notify after a critical injury, and how fast?

Section 51(1) of the OHSA is direct. When a person is killed or critically injured at a workplace, the constructor (if any) and the employer must notify an inspector immediately by telephone or other direct means. That phone number is 1-877-202-0008 — the Ministry of Labour, Immigration, Training and Skills Development Health and Safety Contact Centre. It operates 24 hours a day, 7 days a week, including statutory holidays. "Immediately" means as soon as the scene is safe and emergency services have been contacted. Not at the end of the shift. Not the next morning. Not after you talk to your lawyer. Immediately. The same section requires you to also notify the joint health and safety committee (JHSC) or health and safety representative, and the trade union if one exists, immediately. These are separate from the MOL call — do not assume one notification covers the others. The practical sequence on site is: call 911 if needed, stabilize the scene, call MOL at the number above, then notify your JHSC member and union steward. A written report must follow within 48 hours to a MOL Director. That report must contain prescribed information including names, time, location, description of what happened, and the nature of the injuries. Assign someone to start writing it within the first hour while details are fresh.

What can you touch after a workplace critical injury? (Scene preservation)

This is the rule that trips people up the most. Under OHSA section 51(2), when a person is killed or critically injured at a workplace, no person shall interfere with, disturb, destroy, alter, or carry away any wreckage, article, or thing at the scene of or connected with the occurrence until an MOL inspector gives permission. The only three exceptions are narrow and specific: (a) saving life or relieving human suffering, (b) maintaining an essential public utility service or a public transportation system, and (c) preventing unnecessary damage to equipment or other property. That means you do not clean up the blood. You do not move the ladder. You do not coil the rope. You do not pick up tools. You do not power-wash the area. You rope it off and you wait. The inspector needs to see the scene exactly as it was. Photographs help, but they do not replace the physical scene. If you moved something to save a life — that is fine, that is exception (a). Document exactly what you moved and why. When the inspector arrives, walk them through it. The biggest enforcement action I have seen on a construction site was not for the fall itself — it was for disturbing the scene before the inspector arrived. The company argued they were "preventing damage." The inspector did not agree. Preserve the scene.

What must the 48-hour written report contain?

After the immediate phone call to MOL, OHSA section 51(1) requires the employer to send a written report within 48 hours to a Director of the Ministry of Labour. The regulations prescribe the information this report must contain: the name and address of the employer, the nature of the occurrence, the time and place of the occurrence, the name and address of each person involved, a description of the machinery or equipment involved, the nature of the injuries, the name and address of each witness, the name and address of the physician or surgeon who attended the injured person, and the steps taken to prevent a recurrence. This is not a casual email. It is a formal document that may be used in a prosecution or inquest. Get your facts straight, have someone review it, and keep a copy. The 48-hour clock starts from the time of the occurrence, not from when you finished the phone call. If the incident happens Friday afternoon, the written report is due by Sunday afternoon. Weekends do not extend the deadline. For non-critical injuries under section 52, the written notice deadline is 4 days, and it goes to the JHSC/H&S rep, the trade union, and a MOL Director if an inspector requires it.

When is WSIB Form 7 due after a workplace injury?

Separate from the OHSA reporting obligations, the Workplace Safety and Insurance Act requires the employer to file a WSIB Form 7 (Employer's Report of Injury/Disease) within 3 business days of learning of any workplace injury or illness that causes a worker to require health care or to miss time from work. Business days means Monday through Friday excluding statutory holidays — so a Friday afternoon injury gives you until the following Wednesday. You can file Form 7 online through the WSIB employer portal at wsib.ca. The Form 7 is about the claim, not the investigation. It asks for the worker's information, the date and time of injury, the body part affected, how it happened, and the worker's earnings. Failure to file on time can result in penalties from the WSIB — and if a worker files a Form 6 (worker's report) before the employer files the Form 7, that raises questions the WSIB will follow up on. File early. Even if you are still investigating, file what you know and amend later. The WSIB Form 7 and the OHSA written report serve different purposes and go to different agencies. You need both.

Do you have to report a near-miss in Ontario?

The OHSA does not require you to report a near-miss — an event where no one was injured but easily could have been. A scaffold plank that slips but lands where nobody was standing. A load that swings but misses the worker by a foot. A trench wall that shows signs of failure but nobody is in it yet. None of these trigger section 51 or section 52. But the smartest site supervisors track every single one. Near-misses are leading indicators — they tell you where the next real injury is going to come from before it happens. The CSA Z1000-14 standard on occupational health and safety management recommends formal hazard identification and reporting processes that include near-misses. A five-minute debrief at the toolbox talk, a quick entry in the site log, a photo of the condition — that is all it takes. Sites that track near-misses and act on them have lower critical injury rates. Period. The other practical reason to document near-misses: if a real injury does happen later in the same area or from the same hazard, your near-miss records show the MOL inspector that you were aware of the risk and taking steps. That is the difference between a company that gets orders and a company that gets charges. Track the near-misses.

What are the penalties for not reporting?

According to OHSA s. 66, as amended in force October 26, 2023, failing to notify is an offence carrying maximum fines of up to $500,000 and/or 12 months in jail for an individual, up to $1,500,000 for a director or officer, and up to $2,000,000 for a corporation — per offence. Those are the highest corporate OHS fines in Canada. The lesson from twenty years on Ontario sites is simple: the report is free, the fine is not. When in doubt, phone it in. If you manage crews and want the incident details, timesheets, and job records in one place so the 48-hour report and Form 7 write themselves, ToolFluency's Ontario contractor tools keep the paper trail ready before the inspector asks for it.

About Ontario Critical Injury & Incident Reporting Tool

In Ontario, a workplace injury is a 'critical injury' under O. Reg. 420/21 if it places life in jeopardy, produces unconsciousness, causes substantial loss of blood, involves the fracture of a leg or arm (but not a finger or toe), the amputation of a leg, arm, hand or foot, burns to a major portion of the body, or loss of sight in an eye. A critical injury or a workplace death triggers immediate phone notification to the Ministry of Labour under OHSA s. 51(1) at 1-877-202-0008, plus a written report within 48 hours.

By the ToolFluency team · Updated September 2026

Free OHSA critical injury reporting decision tool. Answer 3 questions about a workplace incident and get your exact reporting obligations — who to call, when, scene preservation rules, written report deadlines, and WSIB Form 7 timeline. Covers O. Reg. 420/21 critical injury criteria, OHSA sections 51-52, and WSIB employer reporting.

How to use

Pick the tile that matches what happened: worker death, injury, illness or exposure, or near-miss. For an injury, the wizard then asks whether it meets any of the seven O. Reg. 420/21 critical-injury criteria (life in jeopardy, unconsciousness, substantial blood loss, fracture of an arm or leg but not a finger or toe, amputation of a leg, arm, hand or foot, burns to a major portion of the body, or loss of sight in an eye).
Answer whether the worker is disabled from regular duties or returned to work the same shift. That decides whether you fall under OHSA s. 51 (critical or fatal), s. 52(1) (disabling injury), or a first-aid record only. OHSA s. 51 notification applies to every Ontario workplace regardless of the number of workers.
On a construction project, identify both the constructor and the employer. Both carry parallel s. 51(1) duties to notify an MOL inspector, the joint health and safety committee or health and safety representative, and the trade union. On a multi-employer site, a missed constructor notification is a common citation even when the employer has called.
Read the verdict: Critical injury, Reportable, or Record only. The tool lists who to call and by when: the MOL inspector at 1-877-202-0008 (24/7) immediately for criticals and fatalities under s. 51(1), a written report to a Director within 48 hours (contents prescribed by O. Reg. 420/21 s. 3), and the 4-day s. 52(1) written notice for a disabling injury.
Apply the scene-preservation rule under OHSA s. 51(2) before anything is moved: touch nothing except to save life or relieve human suffering, maintain an essential public utility or public transportation system, or prevent unnecessary damage to equipment or property. Photograph everything from several angles and time-stamp witness statements while the scene stays untouched.
Confirm the parallel WSIB Form 7 deadline: 3 business days from learning the worker needed health care beyond first aid, missed time beyond the day of injury, or earned less than regular pay. File through the employer portal at wsib.ca. A late Form 7 triggers WSIB penalties and experience-rating impact independent of the OHSA file.
Print the incident summary: the classification, who must be notified and by when, the scene-preservation duty, and the checklist of details to document now (names, time, place, machinery, injuries, witnesses, attending physician, steps to prevent recurrence) for your 48-hour written report and Form 7.

Examples

Fall from scaffold — fractured femur

Worker fell 4 m, fractured femur, transported to hospital. Verdict: CRITICAL INJURY under O. Reg. 420/21 (fracture of a leg). Action: phone MOL immediately at 1-877-202-0008, preserve the scene under s. 51(2), notify the JHSC worker member and union, send the written report to a Director within 48 hours, and file Form 7 with the WSIB within 3 business days. The scene stays untouched until the MOL inspector arrives.

Cut requiring stitches, no lost time

Worker lacerated a forearm using a saw, 8 stitches at a clinic, returned to modified duty the same day. Verdict: not a critical injury. Form 7 required to the WSIB (health care beyond first aid). The JHSC investigates internally; MOL s. 51 notification is not triggered.

Frequently asked questions

What counts as a 'critical injury' in Ontario?

O. Reg. 420/21 (in force July 1, 2021, replacing R.R.O. 1990 Reg. 834) defines a critical injury as one that places life in jeopardy; produces unconsciousness; results in substantial loss of blood; involves the fracture of a leg or arm but not a finger or toe; involves the amputation of a leg, arm, hand, or foot but not a finger or toe; consists of burns to a major portion of the body; or causes the loss of sight in an eye. Any one of these triggers immediate phone notification to the Ministry of Labour under OHSA s. 51(1).

How fast must the Ministry of Labour be notified after a critical injury or fatality?

OHSA s. 51(1) requires notification 'immediately' by telephone or other direct means, in practice before any cleanup or scene change. The constructor and employer also notify the committee or health and safety representative, the union (if any), and a Director of the Ministry. A written report follows within 48 hours, with the contents prescribed by O. Reg. 420/21 s. 3: nature and circumstances, machinery or equipment involved, witnesses, the attending physician or hospital, and steps taken to prevent a recurrence. The MOL hotline operates 24/7 at 1-877-202-0008.

What does 'preserve the scene' actually require?

OHSA s. 51(2) prohibits any person from interfering with, disturbing, destroying, altering, or carrying away any wreckage, article, or thing at the scene, except to save life or relieve human suffering, maintain an essential public utility or public transportation system, or prevent unnecessary damage to equipment or property. The site stays as-is until an inspector gives permission. Photographs, witness statements, and JHSC member notes can be taken without disturbing physical evidence; under OHSA s. 9(31) the worker members of the committee may designate a member to inspect the scene before it is released.

When is a Form 7 required versus a critical injury notification?

These are two separate obligations. The WSIB Form 7 (Employer's Report of Injury/Disease) goes to the WSIB within 3 business days of learning that a worker required health care beyond first aid, missed time beyond the day of injury, or earned less than regular pay. A critical-injury notification under OHSA s. 51 goes to the MOL immediately for the seven defined critical injuries plus fatalities. A serious incident often requires both: Form 7 to the WSIB for the claim, and OHSA notification to the MOL for the inspection. A late Form 7 exposes the employer to WSIB penalties and adverse experience-rating impact.

Does the JHSC have the right to investigate a critical injury?

Yes. OHSA s. 9(31) lets the worker members of the joint health and safety committee designate one or more members to investigate a case where a worker is killed or critically injured, to inspect the scene (subject to the s. 51(2) preservation rule), and to report findings to a Director and the committee. In a workplace with a health and safety representative instead of a committee, s. 8(14) gives the representative the same inspection right. The employer must provide reasonable assistance, and obstructing this access is itself an OHSA offence.

What happens if we don't report a critical injury?

Failing to notify under OHSA s. 51 is an offence. Under s. 66, as amended and in force October 26, 2023, the maximum fines are up to $500,000 and/or 12 months' imprisonment for an individual, up to $1,500,000 for a director or officer, and up to $2,000,000 for a corporation, per offence. Concealment can also strengthen a Crown case for criminal negligence under Criminal Code s. 217.1. In practice, MOL inspectors learn about unreported critical injuries from hospitals, paramedics, the WSIB Form 7 cross-check, or worker tips, and the consequences are far worse than a timely report.

Is a near-miss reportable to the Ministry of Labour?

Not under OHSA s. 51, which covers actual critical injuries and fatalities. OHSA s. 52(1) still requires written notice within 4 days to the committee or health and safety representative and the union (and to a Director if an inspector requires it) for any incident that disabled a worker from usual work or required medical attention. Where no one is disabled or hurt, there is no statutory MOL report, but internal near-miss tracking is a cornerstone of the Internal Responsibility System and is weighted in WSIB Health and Safety Excellence audits.

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