19 C.F.R. § 146.8
The port director may authorize an operator to break a Customs in-bond seal affixed under § 18.4 of this chapter, or under any Customs order or directive, on any vehicle or intermodal container containing merchandise approved for admission to the zone upon its arrival at the zone; or to affix a Customs in-bond seal to any vehicle or intermodal container of merchandise for which an entry, withdrawal, or other approval document has been obtained for movement in-bond from the zone. The authorized affixing or breaking of that seal will be considered to have been done under Customs supervision. The operator shall report to the port director, upon arrival of the vehicle or container at the zone, any seal found to be broken, missing, or improperly affixed, and hold the vehicle or container and its contents intact pending instructions from the port director. If the operator does not obtain the written concurrence of the carrier as to the condition of the seal or delivering conveyance, the port director shall deem the seal or delivering conveyance to be intact.
19 C.F.R. §146.8