(a) The commission may refuse to examine any applicant, or if examined, may refuse to certify, after examination, any person who is found to lack any of the minimum qualifications for examination prescribed in the rules and regulations adopted for the position or employment for which he has applied, or who is physically unfit for the performance of the duties of the position to which he seeks employment, or who is illegally using a controlled substance, as defined in section 102 of the Controlled Substances Act (Public Law 91-513, 21 U.S.C. § 802), or who has been guilty of any crime involving moral turpitude, or of infamous or notoriously disgraceful conduct, or who has been dismissed from public service for delinquency or misconduct in office, or who is affiliated with any group whose policies or activities are subversive to the form of government set forth in the Constitutions and laws of the United States and Pennsylvania.

(b) If any applicant or person is aggrieved by refusal of the commission to examine or certify the applicant, or to certify him as eligible after examination, the commission shall, at the request of the applicant, within ten days, appoint a time and place for a public hearing, with or without counsel, at which time the commission shall take testimony and review its refusal to provide examination or certification. The decision of the commission shall be final.