If, in the opinion of the planning director, the proposed use may cause the emission of dangerous or objectionable noise, odors, lights, dust, smoke or vibrations, the planning director with the consent of the applicant, may refer the application for investigation and report to one or more expert consultants qualified to advise as to whether a proposed use will conform to the applicable performance standards. Such consultant or consultants shall report in writing to the planning director and a copy of such report shall be furnished to the applicant. The applicant shall be required to pay the fee for service of said consultant(s). (Prior gen. code § 8-95.4)