OIL AND GAS FIELDS Within this area covered by larger scale charts/data, certain fixed structures, pipelines and cables have been omitted due to their complexity and frequent change. The appropriate larger scale data should be used within this area. Production platforms and associated structures, including tanker moorings, storage tankers and platforms on pipelines, generally exhibit Mo(U) lights, aircraft obstruction lights and audible fog signals. Unauthorised navigation is prohibited within 500 metres of all such structures, including storage tankers which can swing about their moorings. Tankers manoeuvring in the vicinity of platforms and moorings should be given a wide berth. Other uncharted structures, both lit and unlit and submerged installations, some marked by buoys, may exist. Additionally, and in accordance with Saudi Seaports Authority Notices to Mariners, the majority of oil and gas field features have been omitted within the Saudi Arabian oilfields.