At any installation where the normal flow of product may be stopped other than by the hose nozzle valve such as at pre-pay stations, the system must include listed equipment with a feature that causes or requires the closing of the hose nozzle valve before product flow can be resumed or before the hose nozzle valve can be replaced in its normal position in the dispenser; or the hose nozzle valve must not be equipped with a latch-open device.
Okla. Admin. Code § 165:26-2-93