Personnel shall be thoroughly instructed and be adequately trained in the operation and use of the carbon monoxide chamber. Carbon monoxide shall be administered in the following manner:
Adult animals, over sixteen (16) weeks of age, to be euthanized, shall be left in the chamber for a minimum of twenty (20) minutes after the carbon monoxide is administered. No animal so euthanized shall be removed until five (5) minutes after cessation of respiratory movements. The animal's body shall not be disposed of until death has been confirmed.
Okla. Stat. tit. 4, § 503