Okla. Stat. tit. 17, § 342

A. Jurisdiction is conferred upon the Corporation Commission, and the same is authorized and empowered, to prescribe and promulgate rules and specifications for safety and quality with reference to regulated substances as it may deem proper from time to time. The Corporation Commission shall prescribe rules governing the test for octane rating on motor fuels and prescribe the rating. B. All specifications as may be prescribed and promulgated by the Corporation Commission shall be accepted as statutory enactments and shall be received as prima facie evidence by any court of competent jurisdiction within the State of Oklahoma.