What is the difference between the California Workers' Compensation Board and the California Civil Court?

Third and more fundamentally, what we are talking about here is subject matter jurisdiction. The only point of jurisdictional concurrency between the WCAB and civil courts is jurisdiction to determine jurisdiction. Once determined, jurisdiction is exclusive, not concurrent, and civil courts have no power to grant relief in matters concerning the workers' compensation remedy. (See Scott v. Industrial Acc. Com. (1956) 46 Cal.2d 76, 82-83.) Finally, subject matter jurisdiction cannot be conferred by waiver, consent or estoppel upon a tribunal otherwise lacking such jurisdiction. (Summers v. Superior Court (1959) 53 Cal.2d 295, 298.)

E. Section 5300 Vests Exclusive Jurisdiction in the WCAB Over This Dispute