Tank vehicle and tank car loading and unloading facilities must be separated from aboveground tanks, warehouses, other plant buildings or the nearest line of adjoining property that can be built upon by a distance of at least 25 ft (7.6 m) for Class I liquids and at least 15 ft (4.6 m) for Class II and Class III liquids, measured from the nearest fill spout or transfer connection.
Okla. Admin. Code § 165:26-14-63