Okla. Stat. tit. 62, § 62-310.8

A. A municipality, county or school district may issue a

blanket purchase order for:

1. Recurring purchases of goods or services if a maximum

authorized amount for all purchases pursuant to a blanket purchase

order is specified in the order and approved by the governing board;

or

2. The repair of county equipment, machinery or vehicles when

the estimated cost of repairs is greater than Five Thousand Dollars

($5,000.00). The maximum authorized amount of a blanket purchase

order may be increased to cover unforeseen expenses. A written

explanation of said increase shall be attached to the blanket

purchase order prior to payment.

B. Blanket purchase orders shall be prepared, filed, and

encumbered in the manner provided for purchase orders and as

authorized by law or regulation, except no written requisition shall

be required for a blanket purchase order. Prior to payment, the

requesting county officer shall verify the blanket purchase order by

signature. Before transacting any purchase pursuant to a blanket

Oklahoma Statutes - Title 62. Public Finance Page 379

purchase order, the order shall be submitted to the governing board

for its approval. After satisfactory delivery of goods or services

pursuant to a blanket purchase order, a vendor's invoice shall be

submitted to and approved by the purchasing officer of a

municipality or a school district or a county purchasing agent and

forwarded for payment. An itemized list of goods or services

purchased pursuant to the blanket purchase order shall be attached

to the vendor's invoice if said invoice does not contain an itemized

list of goods or services purchased pursuant to the blanket purchase

order. Payment of invoices from vendors pursuant to a requisition

and approved blanket purchase order issued pursuant to the

provisions of this section shall be authorized by the encumbering

officer.