19 U.S.C. § 81o: Residents of zone

No person shall be allowed to reside within the zone except Federal, State, or municipal officers or agents whose resident presence is deemed necessary by the Board. The Board shall prescribe rules and regulations regarding employees and other persons entering and leaving the zone. All rules and regulations concerning the protection of the revenue shall be approved by the Secretary of the Treasury. The Board may at any time order the exclusion from the zone of any goods or process of treatment that in its judgment is detrimental to the public interest, health, or safety. No retail trade shall be conducted within the zone except under permits issued by the grantee and approved by the Board. Such permittees shall sell no goods except such domestic or duty-paid or duty-free goods as are brought into the zone from customs territory. Tangible personal property imported from outside the United States and held in a zone for the purpose of storage, sale, exhibition, repackaging, assembly, distribution, sorting, grading, cleaning, mixing, display, manufacturing, or processing, and tangible personal property produced in the United States and held in a zone for exportation, either in its original form or as altered by any of the above processes, shall be exempt from State and local ad valorem taxation.