ADJ14466153 · October 21, 2025

The WCJ found no injury AOE/COE due to lack of medical expert opinion and less than credible testimony, but the Appeals Board found the record insufficiently developed and remanded for further medical discovery and expert opinion.

From the decision · page 1Applicant seeks reconsideration of the Findings and Order (F&O) issued by a workers' compensation administrative law judge (WCJ) on June 3, 2022, wherein the WCJ found that while employed by defendant on June 17, 2020 as a machinist, applicant did not sustain injury arising out of and in the course of employment (AOE/COE) to his back, bilateral hips, bilateral legs, and bilateral feet.

Applicant and defendant's HR manager both testified that applicant requested work accommodations which were denied.

Favours neutral

This testimony, although applicant was found less than credible, was not fully discredited and is relevant to the injury claim.

From the decision · page 3Applicant testified that after the alleged injury he told Wendy (human resource manager) he was injured on the floor and was told "We don't know if we can accommodate you." (MOH March 22, 2022, page 5, lines 24 to 25; See Exhibit 16, Deposition of the applicant, June 30, 2021, page 36, lines 3 to 15.)

There was no medical expert opinion in the record addressing causation of the alleged injury.

Favours neutral

The lack of expert medical evidence prevented a finding of injury AOE/COE and required remand for further medical discovery.

From the decision · page 5In the June 2, 2022, order, the WCJ finds applicant did not sustain injury AOE/COE and in the accompanying opinion on decision concludes "[a]pplicant has numerous medical issues, however, none of which are industrially related." In the Report, the WCJ states "the record is void of medical evidence supporting Applicant's contention he sustained injury arising out of and in the course of employment" and therefore applicant failed to meet his burden of proving injury pursuant to Labor Code Section 3202.5. (Report, p. 3.)

Applicant had pre-existing medical conditions including chronic low back pain and peripheral neuropathy before employment with defendant.

Favours neutral

This pre-existing condition required expert medical opinion to determine causation of the alleged injury.

From the decision · page 2Prior to the alleged injury applicant was seen as early as September 24, 2019, at Kaiser for chronic low back pain and peripheral neuropathy. (Exhibit 1, Kaiser Report, September 24, 2019, page 4.)

Lab. Code, 3600(a)

An employee bears the burden of proving injury AOE/COE by a preponderance of the evidence.

The Board applied this standard to assess the burden of proof on the applicant.

From the decision · page 4B. Section 3600(a) provides liability for injuries sustained "arising out of and in the course of the employment." An employer is liable for workers' compensation benefits "without regard to negligence." (Lab. Code, § 3600(a).) An employee bears the burden of proving injury AOE/COE by a preponderance of the evidence. (South Coast Framing, Inc. v. Workers' Comp. Appeals Bd. (Clark) (2015) 61 Cal.4th 291, 297-298, [80 Cal.Comp.Cases 489]; Lab. Code, § 3600(a), 3202.5.) Whether an employee's injury arose out of and in the course of employment is generally a question of fact to be determined in light of the particular circumstances of the case. (Wright v. Beverly Fabrics (2002) 95 Cal.App.4th 346, 353 [67 Cal.Comp.Cases 51].)

South Coast Framing, Inc. v. Workers' Comp. Appeals Bd. (Clark) (2015) 61 Cal.4th 291

Medical evidence that industrial injury was reasonably probable constitutes substantial evidence for a finding of injury AOE/COE.

The Board noted that reasonable probability of industrial injury is sufficient for causation.

From the decision · page 5For the purpose of meeting the causation requirement in a workers' compensation injury claim, it is sufficient if the work is a contributing cause of the injury. (South Coast Framing, Inc. (Clark), supra, at pp. 298-299.) "The applicant in a workers' compensation proceeding has the burden of proving industrial causation by a `reasonable probability.' (citation) That burden manifestly does not require the applicant to prove causation by scientific certainty." (Rosas v. Workers' Comp. Appeals Bd. (1993) 16 Cal.App.4th 1692, 1700-1701 [58 Cal.Comp.Cases 313].) Medical evidence that industrial injury was reasonably probable, although not certain, constitutes substantial evidence for a finding of injury AOE/COE. (McAllister v. Workers' Comp. Appeals Bd. (1968) 69 Cal.2d 408, 417 [33 Cal.Comp.Cases 660].)

Peter Kiewit Sons v. Industrial Acc. Com. (1965) 234 Cal.App.2d 831

Expert medical opinion is essential to sustain a finding of injury when the issue is exclusively medical.

The Board emphasized the necessity of expert medical opinion for injury determination.

From the decision · page 5Although the factual issue of the occurrence of the alleged incident is a determination for the WCJ, the issue of injury is a medical determination, which requires expert medical opinion. As the Court of Appeal explained in Peter Kiewit Sons v. Industrial Acc. Com. (1965) 234 Cal.App.2d 831, 838 [30 Cal.Comp.Cases 188]: "Where an issue is exclusively a matter of scientific medical knowledge, expert evidence is essential to sustain a [WCAB] finding; lay testimony or opinion in support of such a finding does not measure up to the standard of substantial evidence. Expert testimony is necessary where the truth is occult and can be found only by resorting to the sciences."

Applicant's testimony was found less than credible by the WCJ but was not fully discredited; both applicant and HR manager testified about denied work accommodation requests.

From the decision · page 7The WCJ's decision was in part "based on Applicant's less than credible testimony". In workers' compensation proceedings, a WCJ's credibility determinations are "entitled to great weight because of the [WCJ's] `opportunity to observe the demeanor of the witnesses and weigh their statements in connection with their manner on the stand....' [Citation.]" (Garza v. Workmen's Comp. App. Bd. (1970) 3 Cal.3d 312, 318-319 [35 Cal.Comp.Cases 500].)