California Labor Code Section 5900 - Final Order Definition
A "final order" for purposes of section 5900 includes any order which settles, for purposes of the compensation proceeding, an issue critical to the claim for benefits, whether or not it resolves all the issues in the proceeding or represents a decision on the right to benefits. (Kaiser Foundation Hospitals v. Workers' Comp. Appeals Bd. (1978) 82 Cal. App. 3d 39, 45 [147 Cal. Rptr. 30]; Safeway, supra, 104 Cal. App. 3d 528, 534-535; Rymer v. Hagler (1989) 211 Cal. App. 3d 1171, 1179 [260 Cal. Rptr. 76]; 2 Hanna, Cal. Law of Employee Injuries and Workers' Compensation (2d rev. ed. 1995) 28.04, pp. 28-12 to 28-14.)
"For example, an interim order of the Board or a workers' compensation judge that presents a threshold issue is deemed to be final, and may properly be the subject of a petition for reconsideration.
A threshold issue is an issue that is basic to the establishment of the employee's rights to benefits, such as the territorial jurisdiction of the Board, the existence of the employment relationship, and statute of limitations issues.
Likewise, the term 'final order' includes orders dismissing a party, rejecting an affirmative defense, granting commutation, terminating liability, and determining whether the employer has provided compensation coverage." (2 Hanna, Cal. Law of Employee Injuries and Workers' Compensation, supra, 28.04, pp. 28-12 to 28-13, fns. omitted; see also Kosowski v. Workers' Comp. Appeals Bd., supra, 170 Cal. App. 3d 632, 636, fn. 2; Safeway, supra, 104 Cal. App. 3d at p. 533.)
It follows that interim orders, which do not decide a threshold issue, such as intermediate procedural or evidentiary decisions, are not "final" for purposes of section 5900. (See Safeway, supra, 104 Cal. App. 3d at p. 534; Hughes v. Willig Freight (1981) 46 Cal.Comp.Cases 685, 688.)