Okla. Stat. tit. 19, § 19-1220: Tax exemption

Districts formed hereunder shall be exempt from all excise taxes

and, further, shall be exempt from payment of assessments in any

general or special taxing district levied upon the property of the

district, whether real, personal, or mixed. Any and all securities

and evidences of indebtedness issued by a district created pursuant

to the Ambulance Service Districts Act and the income interest and

capital gains thereon shall not be subject to the income tax laws of

this state and persons owning or holding the securities and

evidences of indebtedness or their heirs, devisees, successors, or

assigns shall not be required to pay to the State of Oklahoma income

tax upon the profits and capital gains upon the securities and

evidences of indebtedness.