Whenever any portion of an existing underground steel facility is exposed by the operator, a galvanic type anode shall be attached to that facility if consistent with good corrosion control practices. Whenever an operator has knowledge that any portion of a buried pipeline is exposed, the exposed portion must be examined for evidence of external corrosion if the pipe is bare, or if the coating is deteriorated. If external corrosion is found, the operator shall investigate circumferentially and longitudinally beyond the exposed portion (by visual examination, approved indirect method, or both) to determine whether there is additional corrosion, and remedial action must be taken to the extent required by the applicable subdivisions of sections 255.483, 255.485, 255.487, and 255.489 of this Part.