In Harrison v. Workmen's Comp. Appeals Bd. (1974) 44 Cal.App.3d 197, the issue was whether the five-year limitation applied to a pending case in which the injury had occurred prior to the effective date of the 1973 amendment. The court recognized that applying the amendment retrospectively might substantially affect the rights and liabilities of the employers who came within the five-year period. Nevertheless, the court concluded that the Legislature intended the amendment to apply retrospectively, and accordingly, the court affirmed the board's order dismissing those insurance carriers which had not provided insurance within five years prior to the date of injury.