If you were hurt at work in California, the clock started running the moment it happened. California's workers' compensation system has hard deadlines — miss even one of them and you can lose your right to benefits permanently, no matter how serious your injury is. Insurance carriers know these dates better than most injured workers do. That's not an accident.
We've recovered over $150,000,000 for injured workers across Southern California. The cases we've seen fall apart before they even begin almost always trace back to one of the five deadlines below. Read every one.
Here are the 5 deadlines that can kill your California workers' comp claim:
- 30 days to report your injury to your employer (Cal. Lab. Code §5400)
- One year to file your formal workers' comp claim (Cal. Lab. Code §5405)
- Discovery rule for cumulative trauma — the clock starts at awareness, not at exposure (Cal. Lab. Code §5412)
- 30 days to request Independent Medical Review after a treatment denial (Cal. Lab. Code §4610)
- Five years to reopen for new and further disability (Cal. Lab. Code §5410)
If any of these are running right now, call (818) 794-9947. A free case review costs you nothing. Waiting could cost you everything.
1. 30 Days to Report Your Injury to Your Employer
Under California Labor Code §5400, you have 30 days from the date of your injury to notify your employer in writing — miss that window and you could lose your right to benefits entirely.
This is the deadline most injured workers don't know exists. You might assume your supervisor saw the accident, or that HR already knows, or that it's obvious. None of that is enough. Cal. Lab. Code §5400 requires written notice to your employer within 30 days of the injury date. Verbal reports and bystander witnesses do not satisfy the requirement.
What counts as proper notice? The notice must identify the time, place, nature, and cause of the injury. You can deliver it to your supervisor, employer, or the employer's workers' comp insurance carrier. Written — meaning email, text with a timestamp, or a completed DWC Form DWC 1 (the Workers' Compensation Claim Form) — is your safest path. Your employer is legally required to provide that form to you within one working day after learning of your injury under Cal. Lab. Code §5401, but don't wait for them to hand it to you.
What happens if you miss it? Missing the 30-day window does not automatically kill your claim — there are limited exceptions for cases where the employer had actual knowledge of the injury — but it gives the insurer a powerful argument to deny your benefits. Courts have enforced this bar against injured workers who delayed notification even by a few weeks.
For cumulative trauma injuries (repetitive stress, hearing loss, carpal tunnel), the 30-day clock runs from the date you knew or should have known the injury was work-related — not from when you first started feeling pain. More on how that rule works in item 3.
Practical takeaway: Report your injury in writing the same day it happens, or the next business day at the latest. If you're reading this and more than a week has passed without written notice, call us today at (818) 794-9947 — the window is closing.
2. One Year to File Your Workers' Comp Claim
California Labor Code §5405 gives injured workers one year from the date of injury to file a formal workers' comp claim with the Workers' Compensation Appeals Board.
One year sounds like a long time. It isn't. Between treating your injury, managing your household on reduced income, and navigating an employer who may suddenly be acting differently toward you, months disappear fast. And unlike the 30-day notice requirement, missing this statute of limitations is almost always fatal to your claim. The WCAB has very little power to resurrect a claim filed after Cal. Lab. Code §5405 expires.
What "filing" means here: Filing means submitting the DWC Form DWC 1 to your employer or their insurer, which triggers the formal claim. The insurer then has 90 days to accept or deny the claim under Cal. Lab. Code §5402. If they don't act within those 90 days, liability is presumed — a significant protection that only applies if you've filed in the first place.
Important tolling exceptions: The one-year clock can be paused ("tolled") in certain situations:
- If your employer provided benefits (medical care, temporary disability payments) after the injury, the clock may pause for the period during which those benefits were being paid — this is one of the most commonly misunderstood tolling rules.
- If you were a minor at the time of injury.
- If a psychiatric injury prevented you from filing.
Tolling rules are fact-specific. Do not assume they apply to you without talking to a workers' comp attorney.
The one-year trap: Many workers file the DWC 1 with their employer promptly but then don't pursue the claim further when the employer says "we'll handle it" — and then discover at month 13 or 14 that no formal proceeding was ever opened with the WCAB. "We'll handle it" is not a filing. Always confirm in writing that a claim has been formally opened.
Practical takeaway: File your DWC 1 immediately after reporting your injury. If you're within a few months of the one-year mark and haven't yet formally filed, call (818) 794-9947 today. We handle workers' compensation cases across Southern California and can tell you exactly where you stand.
3. The Discovery Rule for Cumulative Trauma Injuries
For cumulative trauma injuries — like carpal tunnel or chronic back pain from repetitive work — the one-year clock starts on the date you first knew or reasonably should have known the condition was work-related, under California Labor Code §5412.
Not every work injury happens in a single moment. Repetitive stress injuries, hearing loss, lung disease, carpal tunnel syndrome, and chronic back conditions caused by years of physical labor don't come with a single "injury date." That created a problem for injured workers under the standard one-year rule: when does the clock start for a condition that built up over years?
Cal. Lab. Code §5412 answers that question. For cumulative trauma injuries, the statute of limitations begins to run on the later of two dates: (1) the date your exposure ended, or (2) the date you first suffered disability AND knew or reasonably should have known that the disability was work-related.
What "knew or should have known" actually means: Courts look at when you had a diagnosis that connected your condition to your work, or when a physician told you that your job duties were causing or aggravating your condition. If a doctor told you in March 2024 that your wrist pain was caused by your assembly-line job, your §5412 clock likely started in March 2024 — not the first day you felt pain.
Why this matters for construction workers, warehouse workers, and drivers: These are the three occupations we see cumulative trauma claims from most often. A construction laborer with chronic knee damage from years of kneeling, a warehouse picker with a degenerative shoulder condition from repetitive overhead lifting, a delivery driver with a lumbar disc condition from years of vibration and loading — all of these can qualify under §5412, even if the worker has been off that job for months.
The 30-day notice rule applies here too: Under §5400, the 30-day employer-notification clock also runs from the §5412 discovery date for cumulative injuries. So if your doctor connected your shoulder to your work in March, you have 30 days from March to notify your employer — not 30 days from your last day on the job.
Practical takeaway: If you've been diagnosed with a repetitive stress condition or an occupational disease and a doctor has told you it's related to your work, your deadlines are running from that conversation. Read more in our post on the 30-day reporting rule, then call (818) 794-9947 to confirm your specific timeline.
4. Tight Windows to Appeal a Treatment Denial
If your doctor requests treatment and the insurer issues a Utilization Review denial, you have 30 days to request Independent Medical Review — miss that deadline and the denial is final under California Labor Code §4610.
Your claim is open, liability is admitted, and your treating physician has requested surgery, physical therapy, or a specific medication. Then you get a letter: denied. This is a Utilization Review (UR) denial — and it comes with one of the tightest appeal windows in all of California workers' comp.
Under Cal. Lab. Code §4610, the insurer's Utilization Review organization must issue a decision within specific timeframes after receiving a treatment request:
- Prospective or concurrent reviews: decision within five business days (or 72 hours for urgent cases)
- Retrospective reviews: decision within 30 days
Once the UR denial issues, the injured worker has 30 days to request Independent Medical Review (IMR) through the DIR. IMR is handled by a state-contracted independent physician who reviews whether the denial was appropriate under evidence-based medicine guidelines. If the IMR reviewer overturns the denial, the insurer must authorize the treatment.
Why this deadline is especially dangerous: Most injured workers don't read UR denial letters carefully. The letters are dense. The 30-day IMR request window is often buried in the fine print. We've seen workers miss the window by as little as two or three days — and the WCAB has no authority to extend it. The denial becomes final and binding.
What happens if you miss the IMR window: You can still file a Petition for Reconsideration with the WCAB in limited circumstances, and in some cases your treating physician can submit a new treatment request that restarts the UR process. But you've lost time, possibly months of authorized treatment, and you've given the insurer leverage.
For expedited review requests: If your treating physician documents that your condition is urgent, you can request expedited UR. The insurer must respond within 72 hours. If the insurer fails to meet the UR timeframe, the treatment may be deemed approved by operation of law — a powerful protection, but only if you know to invoke it.
Practical takeaway: Read every UR denial letter the day it arrives. Calendar the 30-day IMR deadline immediately. If you've received a treatment denial and you're not sure what to do, call (818) 794-9947 or visit our page on denied workers' comp claims. We fight these denials regularly.
5. Five Years to Reopen for New and Further Disability
California Labor Code §5410 gives injured workers five years from the date of injury to petition to reopen a case if the disability has worsened — after that, the right is permanently gone.
You settled your workers' comp case. You signed a Compromise & Release (C&R) or a Stipulation with Request for Award. You thought you were done. Then, two years later, the injury gets worse — the back pain becomes debilitating, the knee you thought was healed needs surgery, the partial hearing loss becomes profound. Can you go back?
Sometimes. Cal. Lab. Code §5410 gives workers the right to petition the WCAB to reopen a case for "new and further disability" within five years of the date of injury. This is not a do-over — it's a recognition that some injuries progress in ways that weren't fully known at settlement.
Critical distinction — C&R vs. Stipulation: This right applies primarily to cases resolved by Stipulation with Request for Award. A Compromise & Release, by contrast, is a full and final settlement that typically closes ALL future medical and indemnity claims — including the right to reopen. Before you sign a C&R, you must understand that you are giving up §5410 rights. A Stipulation with Award preserves those rights (subject to the five-year window). This is one of the most consequential decisions in a workers' comp case, and it is exactly the kind of choice no injured worker should make without an attorney.
What "new and further disability" means: The worsening must be objectively documented — usually through a new medical evaluation showing that your permanent disability rating has increased, or that you now need medical treatment you didn't need at the time of settlement. A general statement from your doctor that "you're feeling worse" is not sufficient.
The five-year clock is absolute: Unlike the one-year statute of limitations, there are virtually no tolling exceptions to the five-year §5410 window. California courts have consistently enforced it as a hard cutoff. If your injury date was January 1, 2021, and you don't file a petition to reopen by January 1, 2026, that right is gone.
Practical takeaway: If your condition has worsened and you settled by Stipulation, check your injury date today. If you're within the five-year window, call (818) 794-9947 and ask for a free case evaluation. We'll review your prior award and tell you whether a reopening petition makes sense. You can also start with our free case evaluation quiz.
What Happens If You Miss a Deadline?
Missing a workers' comp deadline in California rarely comes with a warning. The insurance carrier won't call to remind you. Your employer won't flag it. The WCAB won't send a notice. The consequence — a permanently barred claim, a final treatment denial, a closed case that can't be reopened — arrives quietly, often months after the deadline passed.
In our experience, workers who miss deadlines fall into two groups: those who didn't know the deadline existed, and those who were told "don't worry, we'll handle it" by someone who didn't. Neither group deserved to lose their benefits.
If you're worried you may have missed a deadline, don't assume the worst before speaking to an attorney. Some deadlines have tolling exceptions. Some facts change the calculus. The only way to know for certain is to have an attorney review the specific dates in your case.
Call (818) 794-9947 for a free consultation. No fee unless we win.
Frequently Asked Questions
How long do I have to file a workers' comp claim in California?
Under Cal. Lab. Code §5405, you have one year from the date of injury to file a formal workers' comp claim. For cumulative trauma injuries, the one-year clock runs from the date you knew or should have known your condition was work-related, under Cal. Lab. Code §5412. Missing this deadline almost always permanently bars your claim.
What happens if I miss the 30-day reporting deadline?
Missing the 30-day employer-notification requirement under Cal. Lab. Code §5400 gives the insurer a strong basis to deny your claim. Courts have upheld denials based on late notice. Limited exceptions exist when the employer had actual prior knowledge of the injury. If you've missed this window, contact a workers' comp attorney immediately to assess whether any exceptions apply to your case.
Can I reopen a closed workers' comp case?
Yes — but only under specific conditions and within a hard deadline. Cal. Lab. Code §5410 allows you to petition the WCAB to reopen a case for new and further disability within five years of the date of injury. This right typically applies to cases settled by Stipulation with Request for Award. Cases resolved by Compromise & Release (C&R) generally cannot be reopened. After five years from the injury date, the right is permanently extinguished.
What is the deadline to appeal a denied treatment request?
Once your insurer issues a Utilization Review (UR) denial under Cal. Lab. Code §4610, you have 30 days to request Independent Medical Review (IMR) through the California Department of Industrial Relations. Miss that 30-day window and the denial becomes final. This is one of the most commonly missed deadlines in active workers' comp cases.
Does the one-year filing deadline apply to repetitive stress injuries?
Yes, but the clock runs differently. For cumulative trauma injuries — carpal tunnel, chronic back conditions, hearing loss, and similar conditions — Cal. Lab. Code §5412 sets the start date as the later of: (1) the date exposure ended, or (2) the date you suffered disability and first knew or reasonably should have known the condition was work-related. A formal diagnosis connecting your condition to your job duties typically triggers this clock.
Does my employer's workers' comp insurance carrier have to respond within a certain time?
Yes. Under Cal. Lab. Code §5402, the insurer has 90 days after receiving your claim form to accept or deny the claim. During those 90 days, the insurer must authorize up to $10,000 in medical treatment. If the insurer fails to deny your claim within 90 days, liability is presumed by operation of law.
What if my employer told me not to file a workers' comp claim?
Discouraging an employee from filing a workers' comp claim is illegal under California law. If your employer pressured you not to file and the deadline has now passed, that conduct may be relevant to tolling arguments or to a separate retaliation claim under Cal. Lab. Code §132a. Call (818) 794-9947 to discuss your specific facts.
Should I hire a workers' comp attorney to track these deadlines?
Yes. California's workers' comp system has multiple overlapping deadlines — some as short as 30 days — and the insurance carrier's adjusters track every one of them. Workers represented by attorneys consistently recover more than those without representation, and a missed deadline is irreversible. Nordanyan Law handles workers' compensation cases across Southern California on a contingency basis — no fee unless we win. Schedule a free consultation or call (818) 794-9947 today.
Every deadline above represents a hard stop built into the California workers' comp system. Insurance carriers depend on injured workers not knowing these dates. We depend on making sure you do.
If your injury is recent, your clock is running. If your case is already open, there may be appeal and reopening windows you haven't yet acted on. Either way, a 15-minute call with our team costs you nothing and could protect everything.
Call (818) 794-9947 for a free consultation. No fee unless we win. Available in English and Spanish.
Reviewed by Minas Nordanyan, CA Bar #296806. Last reviewed June 2026.