Abstract: A security housing for surrounding a valve attached to a storage tank comprising a pair of hinged clamshell structures (e.g., hollow semi-cylindrical enclosures) that are also pivotally hinged to the storage tank adjacent to an outlet pipe with valve such that the clamshell structure when closed surrounds the valve, yet swings away from the valve to allow access thereto. The security housing is further equipped with an opening which allows manual access to a padlock and padlock eyelets on the interior of the housing. Such a structure is useful to prevent unauthorized access to crude oil stored in the oil field and the like.