It shall be unlawful and an offense for any person to use, obstruct or operate in connection with any producing well within the city any crude oil storage tanks except to the extent of two (2) steel tanks for oil storage, not exceeding five hundred (500) barrels' capacity each, and so constructed and maintained to be vapor tight and each surrounded with an earthen fire wall at such distance from the tanks as will under any circumstances hold and retain at least one-half (1/2) times the maximum capacity of such tank. A permittee may use, construct and operate a steel conventional separator, and such other steel tanks and appurtenances as are necessary for treating oil, with each of such facilities to be so constructed and maintained as to be vapor tight. Each oil gas separator shall be equipped with both a regulation pressure relief safety valve and a bursting head. (1991 Code § 14-17)