California Labor Codes 5402 1080
§ Knowledge of injury; Limitation on medical liability
(a) Knowledge of an injury, obtained from any source, on the part of an employer, his or her managing agent, superintendent, foreman, or other person in authority, or knowledge of the assertion of a claim of injury sufficient to afford opportunity to the employer to make an investigation into the facts, is equivalent to service under Section 5400.
(b) If liability is not rejected within 90 days after the date the claim form is filed under Section 5401, the injury shall be presumed compensable under this division. The presumption of this subdivision is rebuttable only by evidence discovered subsequent to the 90-day period.
(c) Within one working day after an employee files a claim form under Section 5401, the employer shall authorize the provision of all treatment, consistent with Section 5307.27 or the American College of Occupational and Environmental Medicine's Occupational Medicine Practice Guidelines, for the alleged injury and shall continue to provide the treatment until the date that liability for the claim is accepted or rejected. Until the date the claim is accepted or rejected, liability for medical treatment shall be limited to ten thousand dollars ($10,000).
(d) Treatment provided under subdivision (c) shall not give rise to a presumption of liability on the part of the employer.