Okla. Stat. tit. 63, § 683.16

No person shall be employed in any capacity in any emergency management organization who advocates or has advocated a change by force or violence in the constitutional form of the government of the United States or in this state or the overthrow of any government in the United States by force or violence, or who has been convicted of or is under indictment or information charging any subversive act against the United States. Each person who is appointed to serve in an organization of emergency management shall, before entering upon employment duties, take the Oklahoma Loyalty Oath, in writing, before a person authorized to administer oaths in this state.