for an injury shall be determined by the law in effect at the time of injury ..." 85 0.8.2001 § 3.6(F). The Oklahoma Supreme Court recently summarized the rules governing whether an amended statute can apply retroactively to a worker's compensation claim: The right to compensation and the. obligation to pay such benefits becomes vested and fixed by law at the time of the claimant's injury. Such rights cannot be affected by after-enacted legislation. The statutes in force on the date of injury form a part of the contract and determine the rights and obligations of the parties. No subsequent amendment can operate retrospectively to affect in any way the substantive rights and obligations which are fixed. CNA Ins. Co., ¶ 14, 148 P.8d at 877 (internal citations omitted & emphasis added) (<HOLDING>); see also Sudbury v. Deterding, 2001 OK 10, 19
recognizing that state courts may be able to limit the retroactive effect of their declarations of state law holding immunity from liability is not jurisdictional holding that the basis of liability is negligence and not injury recognizing that substantial change is a defense to a products liability claim holding change of law from apportionment of liability to sole liability of current insurer affected substantive rights of parties and could not be given retroactive effect