Okla. Stat. tit. 18, § 18-592
Fire departments for unincorporated areas - Incorporation
The authority of persons associated together to become
incorporated as a charitable corporation for the purpose of
providing either a volunteer or full-time fire department for an
unincorporated area or place is hereby ratified and confirmed. Such
a corporate fire department shall have authority to provide fire
protective service both to its members and to nonmembers, either
within or without the unincorporated area wherein it is situated.