Okla. Stat. tit. 63, § 124.5

Every person permitted pursuant to the provisions of this division, including those holding federal licenses or permits, shall keep such records as may be required by the State Fire Marshal. Records shall be maintained for a period of not less than five (5) years following the year in which the record is made. All such records shall be open to inspection by the State Fire Marshal and his assistants during normal business hours.