What Is California Labor Code §5402 — the 90-Day Compensability Presumption?

How does the §5402(b) 90-day presumption work in practice?

Once the 90-day clock expires without a denial, the carrier is presumed to have accepted the claim and cannot raise compensability as a defense later.

Under California Labor Code §5402(b), the 90-day clock starts on the date the insurer receives the worker's completed DWC-1 claim form. If the insurer issues neither an acceptance nor a denial by day 90, the injury is presumed compensable. The presumption shifts the burden to the insurer to come forward with evidence discovered after day 90 to overcome it. Pre-existing evidence, medical records, surveillance, witness statements that existed during the 90-day window, cannot rebut the presumption. Related coverage: California workers' comp appeal pillar.

What is the §5402(c) $10,000 immediate-treatment provision?

Section 5402(c) separately requires the carrier to authorize up to $10,000 in immediate medical treatment within one working day of receiving the completed claim form.

Under California Labor Code §5402(c), an insurer must authorize medical treatment under California Labor Code §4600 up to a cumulative cost of $10,000 within one working day of the completed DWC-1, regardless of whether the claim is ultimately accepted or denied. The provision exists to prevent treatment delay during the 90-day investigation window. Treatment authorized under §5402(c) does not extinguish the insurer's right to deny the claim later. Related coverage: California Labor Code §5400 (30-day employer notice rule).

How does §5402 interact with the §5400 30-day notice and §5405 one-year filing deadlines?

Section 5402 interacts with the section 5400 thirty-day worker-notice rule and the section 5405 one-year filing deadline, all three run from different trigger events.

California Labor Code §5400 requires the California worker to give the employer notice of the injury within 30 days, and California Labor Code §5401 requires the employer to provide a DWC-1 claim form within one working day. Once the worker returns the completed DWC-1, the insurer's 90-day decision clock under California Labor Code §5402(b) starts. The one-year statute of limitations under California Labor Code §5405 for filing the application with the WCAB runs on its own track. Lea esta página en español: la regla de 90 días del §5402 (versión en español).

What evidence can the insurer use to rebut the §5402(b) presumption?

The carrier can rebut the section 5402(b) presumption with substantial evidence of non-industrial causation, but must act before the 90-day window closes.

The California Supreme Court held in Rodriguez v. WCAB (1994) that the §5402(b) presumption may be rebutted only by evidence discovered after the 90-day window. Evidence that existed during the 90 days but was not investigated, medical records the insurer never requested, witnesses the insurer never interviewed, cannot rebut the presumption. New evidence developed after day 90 (an admission by the worker, a previously unknown injury cause, surveillance taken after day 90) can rebut it. Statute deep-dive: California Labor Code §5405 (one-year filing deadline).

WCIRB's 2024 data shows that cumulative-trauma claims now represent approximately 18% of all indemnity claims in California (up from 12% in 2015), with the §5500.5 last-year-of-injurious-exposure rule driving most of the multi-employer apportionment volume at WCAB district offices.

Related reading: California pillar guide · §4600 explainer.