Updated October 2026 · 6 min read
Under Labor Code §5412, the date of injury for a cumulative trauma (CT) or occupational disease claim is the date you first suffered disability from the condition and either knew, or reasonably should have known, that it was caused by your work. It is not simply the day your symptoms started or the day you quit.
That one date affects nearly every deadline and dollar figure in a CT claim. The one-year limitations period in Labor Code §5405 runs from it. So does the five-year window for temporary disability under §4656 and for reopening under §5410. The year of your date of injury also sets your temporary disability minimum and maximum. For a 2026 date of injury, those are $264.61 and $1,764.11 a week. Employers often try to push the date earlier, to argue that a claim is too late.
This explainer covers what §5412 says, which claims it applies to, how the two-part test works, a hypothetical timeline, common disputes and what to do.
- For cumulative trauma and occupational disease, the date of injury is when you first suffered disability and knew or should have known work caused it (Labor Code §5412).
- Both parts must be present. Symptoms alone or treatment alone generally don’t set the date.
- Knowledge usually comes from a doctor linking the condition to work, not from your own suspicion.
- The §5412 date controls the one-year filing deadline (§5405), the five-year TD and reopening windows (§§4656, 5410) and your benefit rates.
- Specific injuries use the date of the incident instead (§5411).
What Labor Code §5412 says
Section 5412 is one sentence long. The date of injury in cases of occupational diseases or cumulative injuries is the date “upon which the employee first suffered disability therefrom and either knew, or in the exercise of reasonable diligence should have known, that such disability was caused by his present or prior employment.”
In plain English, two things must both be true before the date of injury is fixed:
- Disability. You first suffered disability from the condition.
- Knowledge. You knew, or with reasonable diligence should have known, that the disability came from your current or a past job.
The date of injury is the first date on which both are present. If you had disability but no reason to connect it to work, the date hasn’t arrived yet. The same is true if you suspected work was the cause but hadn’t yet suffered disability.
Who §5412 applies to
Labor Code §3208.1 divides work injuries into two types:
- Specific injuries come from one incident or exposure. Their date of injury is the date of that incident (Labor Code §5411).
- Cumulative injuries come from “repetitive mentally or physically traumatic activities extending over a period of time.” Section 3208.1 says their date of injury “shall be the date determined under Section 5412.”
Section 5412 also covers occupational diseases, such as conditions caused by long-term exposure at work. Common CT claims include repetitive-motion injuries of the hands, wrists and shoulders; back and knee injuries from years of heavy lifting; hearing loss from noise; and some psychiatric injuries from ongoing workplace stress. See our cumulative trauma guide and our page on carpal tunnel and repetitive strain injuries.
| Type of injury | How the date of injury is set | Statute |
|---|---|---|
| Specific (one incident) | The date of the incident or exposure | LC §5411 |
| Cumulative trauma | First disability plus actual or constructive knowledge that work caused it | LC §§3208.1, 5412 |
| Occupational disease | Same two-part test as cumulative trauma | LC §5412 |
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How the two-part test works in practice
What counts as “disability”?
The statute doesn’t define the word here. California courts have generally read “disability” in §5412 to mean a compensable disability, such as time lost from work (temporary disability) or permanent disability. Symptoms alone, or medical treatment alone, usually are not enough.
What counts as “knowledge”?
Courts have generally held that a worker isn’t expected to diagnose themselves. Knowledge usually comes from a doctor telling you that your condition is work-related. A worker with medical training, or a case where the work connection is obvious, may be treated differently. “Should have known” asks what a reasonable person in your position would have understood.
💡 Example (hypothetical): Rosa has worked as a warehouse picker since 2019. Her wrists start aching in 2023, and she sees her own doctor, who calls it tendinitis and doesn’t link it to work. She keeps working without missing time. In February 2026, a hand specialist tells her the condition is caused by repetitive gripping at work and takes her off work for three weeks. Rosa’s §5412 date of injury is likely February 2026, when she first had disability (lost time) and knowledge that work caused it. Her one-year deadline under §5405 would generally run from that date, subject to tolling and later benefits. A workers’ compensation judge decides the date if the parties disagree.
The §5412 date is often later than employers say. We can review your medical and work history for free.
Why the date of injury matters
- Filing deadline. The one-year period in Labor Code §5405 runs from the date of injury, among other dates.
- TD duration. For injuries on or after 2008, temporary disability is capped at 104 weeks within five years of the date of injury. See Labor Code §4656.
- Benefit rates. TD minimums and maximums, and the permanent disability rules, depend on the date of injury.
- Reopening. The five-year window to claim new and further disability under §5410 runs from the date of injury.
Our workers’ comp calculator lets you see how your date of injury affects your weekly TD rate.
Common disputes over the CT date of injury
“You knew years ago.”
The employer may point to old medical records or complaints of pain to argue an earlier date and a missed deadline. The answer usually depends on whether there was disability at that time and whether anyone told you it was work-related.
Treatment vs. disability
Seeing a doctor or taking medication doesn’t necessarily mean you had “disability” under §5412. Lost time from work or a permanent impairment usually matters more.
Multiple employers or jobs
Section 5412 refers to “present or prior employment.” Long careers with several employers can raise disputes about which period of work caused the condition and which insurer is responsible. Those questions are fact-specific.
CT vs. specific injury
Some workers have both a specific injury and a CT injury to the same body part. Each has its own date of injury, and each may need to be claimed separately.
What to do if you have a cumulative trauma injury
- Tell your doctor about your job duties. Describe the repetitive tasks, lifting or exposures in detail so the medical records reflect them.
- Report it to your employer as soon as a doctor connects it to work. Ask for a DWC-1 claim form and file it. See Labor Code §5401.
- Write down key dates. When symptoms started, when you first missed work, and when a doctor first told you it was work-related.
- Keep medical and attendance records. They are the main evidence for the §5412 date.
- Don’t assume you’re too late. If an employer or adjuster says your CT claim is time-barred, get advice before accepting that.
Related Labor Code sections
- §3208.1: defines specific and cumulative injuries. See Labor Code §3208.1.
- §5411: date of injury for specific injuries.
- §5405: one-year deadline to start proceedings.
- §5402: 90-day presumption after you file the claim form.
- §4656 and §5410: five-year windows that also run from the date of injury.
Frequently asked questions
Is my CT date of injury the day I stopped working?
Not necessarily. Under §5412, it is the first date you had disability and knew, or should have known, that work caused it. That can be before or after your last day of work.
My symptoms started years ago. Is my claim too late?
Not automatically. Symptoms alone usually don’t set the date. If you didn’t have disability, or no one connected the condition to work until recently, the date of injury may be much later.
Does seeing a doctor start the clock?
Treatment alone generally isn’t “disability” under §5412. What matters is when disability and knowledge came together.
Who decides the date of injury?
If the parties disagree, a workers’ compensation judge decides it, based on medical records, work history and testimony.
Can I have a CT claim and a specific injury claim at the same time?
Yes. They are different injuries with different dates of injury, even if they affect the same body part.
Does §5412 apply to psychiatric injuries?
Psychiatric injuries caused by ongoing work events can be cumulative injuries, so the §5412 date-of-injury test can apply. Psychiatric claims also have their own requirements under Labor Code §3208.3.
Related guides
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This article provides general information about California law and is not legal advice for any specific situation. Reading it does not create an attorney-client relationship. Past results do not guarantee a similar outcome.
