What to do next
Read the decision for the actual ground
The letter states why and by when you can contest. Identify which ground applies — événement imprévu et soudain (unforeseen sudden event), relationship to work, or medical sufficiency — because each requires different evidence.
Get medical evidence that addresses that ground
Ask your treating physician to address causation and functional limitation directly, referring to the mechanism of injury. A general note will not move a decision; a report that speaks to the stated ground often will.
Contest within the period on the letter
File the contestation before the stated deadline. Missing it can end your claim regardless of merits. Free assistance is available from union representatives and community groups, and specialised counsel is common in contested files.
Frequently asked questions
Can my employer stop me from claiming?
No. Filing a CNESST claim is your right, and reprisals for exercising it are prohibited. If you face consequences for claiming, that is a separate complaint with its own short deadline.
What if my injury developed gradually?
Occupational disease and repetitive strain claims are recognised but require exposure history and medical opinion linking the condition to the work. They are more evidence-intensive than a single-incident injury.
Do I need a lawyer?
Not required. Advice is most valuable where the employer is contesting, where permanent impairment is in issue, or where a refusal turns on conflicting medical opinion.
Where does a contestation go?
After the CNESST's own review stage, to the Tribunal administratif du travail. The decision letter sets out the route and the period.
This is general information, not legal advice. Laws vary by location and every situation is different — speak with a qualified lawyer about your specific circumstances.