Okla. Stat. tit. 56, § 56-176.1: Investigation or study involving custody, placement or

adoption of children - Fee.

If the district court requests or orders the Department of Human

Services to perform any investigation or study involving the

custody, placement, adoption, or other pertinent matter, with regard

to a child or children with whom the Department is not otherwise

involved, the Department may charge a reasonable sliding scale fee,

subject to standards promulgated by the Commission for Human

Services. The court shall specify the party or parties responsible

for payment of such a fee. Failure to obey the order to pay the fee

may be punished as contempt. The Department may also recover the

fee as is provided by law for the recovery of a debt. The

investigation, or study filed with the court, is subject to the

sovereign immunity of the state and its employees.