Okla. Const. art. IX, § 28

Inspection of books and papers - Examination of officers and agents. The commissioners, or either of them, or such persons as they may employ therefor, shall have the right, at such times as they may deem necessary, to inspect the books and papers of any railroad company or other public service corporation, and to examine, under oath, any officer, agent, or employee of such corporations in relation to the business and affairs of the same. If any railroad company or other public service corporation shall refuse to permit the commissioners, or either of them, or any person authorized thereto, to examine its books and papers, such railroad company or other public service corporation shall, until otherwise provided by law, for each offense, pay to the State of Oklahoma not less than one hundred and twenty-five dollars, nor more than five hundred dollars, for each day it shall so fail or refuse, and the officer or other person so refusing shall be punished as the law shall prescribe.