The Commission shall have the right to direct the conduct of such investigations as it may reasonably deem necessary to carry out its duties prescribed in this Part, and the Department shall have the right to conduct such investigations, and for this purpose the employees of the Department and agents of the Commission have the right to enter at reasonable times on any property, public or private, for the purpose of investigating the condition, construction, or operation of any dam or associated equipment facility or property, and to require written statements or the filing of reports under oath, with respect to pertinent questions relating to the construction or operation of any dam: Provided, that no person shall be required to disclose any secret formula, processes or methods used in any manufacturing operation or any confidential information concerning business activities carried on by him or under his supervision. No person shall refuse entry or access to any authorized representative of the Commission or Department who requests entry for purposes of inspection, and who presents appropriate credentials, nor shall any person obstruct, hamper or interfere with any such representative while in the process of carrying out his official duties. (1967, c. 1068, s. 15; 1973, c. 1262, s. 23.)