A denial letter from the WSIB is not the end of a claim. It is the start of a process with fixed deadlines, and the shortest of them is 30 days.
Workers' compensation in Ontario runs under the Workplace Safety and Insurance Act, 1997. The Act gives you the right to object to almost any decision the Workplace Safety and Insurance Board makes about your claim, and then to appeal to an independent tribunal. What it does not do is wait for you. Here is how the process works, and where people most often lose ground they did not need to lose.
Step one: find the deadline in your letter
Section 120 of the Act sets two objection periods, and which one applies depends on what was decided:
- 30 days for decisions about return to work, re-employment, or work transition. The Act calls work transition labour market re-entry, so look for either phrase in your letter.
- Six months for every other decision, including whether your claim is allowed at all and how much you are paid for lost earnings.
The 30-day category catches people out. A letter saying the Board has found you able to do modified work, or that your employer has offered suitable work, reads like an update. It is a decision, and if you do nothing for a month it stands. Where one letter contains decisions with both time limits, the WSIB applies the six-month limit to the objection, but do not plan around that. Read the deadline printed in the letter and work back from it.
The Board can extend a missed deadline, but it is discretionary. You ask in writing and explain the delay, and if the extension is refused that refusal is itself something you would have to appeal.
Step two: ask for reconsideration, then file an Intent to Object
The WSIB's process starts informally. You can ask the person who made the decision to reconsider it, ideally with new information that answers the reason given for the denial. If that does not change the result, you file an Intent to Object form, or a letter of objection, which the WSIB must receive before the deadline. The decision-maker reviews it first, which the WSIB says generally takes about 14 business days.
If the decision stands, you are sent a copy of your claim file. This is the most underused document in the whole process. Read all of it. The file shows what the Board relied on, what it did not have, and very often a medical report that was never requested or a statement from the employer that was never put to you. Gaps you find here should be filled before the objection goes any further.
Step three: the Appeals Resolution Officer
Once you submit the Appeal readiness form the WSIB sends with your file, the objection goes to an Appeals Resolution Officer. Your employer is given the opportunity to participate, and frequently does. The officer decides whether the objection proceeds as a written review of the file and submissions or as an oral hearing. You can ask for a hearing, but it is the officer's call.
The officer's decision is the Board's final decision. That matters, because it is what starts the clock for the next step.
Step four: appeal to WSIAT
If the Appeals Resolution Officer rules against you, you can appeal to the Workplace Safety and Insurance Appeals Tribunal. WSIAT is separate from the WSIB and is the final level of appeal in the compensation system. Under section 125 of the Act, the notice of appeal must be filed within six months of the final decision. WSIAT can allow more time, but as with the Board's own deadlines that is discretionary, so treat six months as the limit.
A WSIAT appeal is closer to litigation than anything that came before it. The issues are defined, the evidence is assembled into a record, and there is often an oral hearing before a vice-chair or a panel. It is also slower. The Board's internal objection can be measured in months; a tribunal appeal commonly takes longer than that, which is one more reason to get the evidence right the first time.
Why claims are actually lost
Most often, the problem is not that the injury did not happen. It is that the evidence answers a different question from the one the Board decided. Three patterns come up again and again:
- Medical notes that do not address causation. The Board decides whether work caused or significantly contributed to the injury. A family doctor's note that you have a back injury and should rest does not answer that, however sincere it is.
- Pre-existing conditions. A prior injury does not disentitle you, but the Board will ask whether the workplace accident made a real contribution. That needs a medical opinion that deals with the earlier condition directly instead of ignoring it.
- Mental stress claims that run into the exclusion. Since January 1, 2018 the Act covers chronic mental stress as well as traumatic stress. But section 13(5) excludes stress caused by the employer's decisions about your employment, including discipline, changes to your work, and termination. A claim framed around a bad performance review will usually fail. A claim framed around sustained harassment from a co-worker is a different analysis.
What you are claiming for
The most valuable benefit for most workers is loss of earnings: under section 43, 85% of the difference between your net average earnings before the injury and what you earn, or are found able to earn, in suitable available work afterwards. Earnings above an annual ceiling are not counted, and the ceiling that applies is fixed by the year you were injured. For 2026 injuries the WSIB puts it at $121,700; for an earlier injury it is that year's ceiling, indexed each January since, so check the figure for your own injury year. Payments generally continue until the loss ends or you turn 65.
The phrase "able to earn" is where many disputes live. If the Board decides you could do a job paying a certain amount, your benefits are reduced by that amount whether or not you have that job. Challenging that finding usually means challenging the return to work decision that produced it, which brings you back to the 30-day deadline.
Where an injury leaves a permanent impairment, there is also a separate non-economic loss award under section 46, based on the impairment percentage the Board assigns and your age when you were injured. A low rating is objectionable like any other decision.
If your employer is the problem
An employer cannot discourage you from claiming or pressure you to withdraw a claim. Section 22.1 prohibits that, including threats of dismissal or discipline, and since 2025 section 22.2 also prohibits an employer from making false or misleading statements to the Board about a claim. Any agreement to give up your benefits is void under section 16. If you were let go after a workplace injury, the Act's re-employment rules may help, with limits. Under section 41 they apply only where the employer regularly employs 20 or more workers and you had at least one year of continuous employment when injured, so workers at smaller employers are not covered. Where they do apply and you were re-employed and then let go within six months, the employer is presumed to have breached the obligation. But you should ask the WSIB to decide whether the employer complied within three months of the termination; after that the Board is not required to consider the request. A dismissal can also raise a separate claim under employment law.
If someone outside work caused the injury
If you were injured at work by someone who is not protected by the WSIB system, the most common example being a member of the public who hits you while you are driving for work, you may be able to sue as well as claim benefits. Section 30 then requires you to choose one within three months of the accident and tell the Board. The Board can extend that period where it considers it just, but do not count on it. If you do not choose, section 30(6) deems you, absent evidence to the contrary, to have elected not to receive WSIB benefits. Choosing the lawsuit is not always all or nothing: if the judgment comes in below what the benefits would have cost, you can claim benefits for the shortfall, and the same applies to a settlement only if the Board approved it before it was made. Either way, it is a significant decision to make by accident, and it is worth advice before the three months run out.
If you have a decision letter in hand and are not sure which deadline applies, that is a good moment for a free evaluation. You can read more about how I handle these files on the WSIB claims and appeals page.
