Container Seal

A container seal is a numbered, tamper-evident device fixed to the doors of a packed container, so that anyone down the line can see whether the box has been opened since it was loaded. Ocean containers bound for the US normally carry a high-security bolt seal: a steel bolt locked into a barrel, which has to be cut off to open the doors. Each seal carries a unique identification number, and that number travels on the shipping documents.

The US requirement

Under 6 U.S.C. 944, added by the SAFE Port Act and amended in 2007, all containers in transit to the United States had to meet ISO/PAS 17712, the ISO specification for container seals, if DHS had not issued its own rule by April 1, 2008. It had not, so CBP gave notice (CBP Dec. 08-30) that every loaded container, including foreign cargo remaining on board, arriving by vessel at a US port on or after October 15, 2008 must be sealed with an ISO/PAS 17712 seal. CBP treats a container that arrives with no seal, or with a seal that does not meet the standard, as a violation and may assess a civil penalty against the party responsible under 19 U.S.C. 1595a(b). Tanks, open tops and custom-built containers that cannot take such a seal are not subject to the requirement.

ISO 17712 and class H

• Three classes: ISO 17712 grades seals by strength as "I" (indicative), "S" (security) and "H" (high security). CTPAT requires class H, and its security criteria say a high-security seal must be affixed to all loaded containers bound for the US
• Independent testing: the seal's class must be confirmed by a third-party laboratory accredited to ISO/IEC 17025, the maker's security practices audited under the standard's Annex A, and the design shown to leave evidence of tampering
• Proof: CTPAT members that keep seal stock must be able to document, for example with a laboratory test certificate, that their seals meet the current ISO 17712 standard

The seal number on the paperwork

The CTU Code, the international code of practice for packing containers, has the packer fit a seal as soon as packing is complete and report its number to the shipper, who passes it to the carrier. The ocean carrier must transmit the numbers of all seals on each container to CBP in its electronic cargo declaration 24 hours before the cargo is loaded at the foreign port, alongside the bill of lading data (19 CFR 4.7 and 4.7a). Send the seal number with your shipping instructions so the bill and the manifest match what is on the door.

VVTT: checking a seal

The CTPAT minimum security criteria have a trained person fit the seal with a second person witnessing, check it with the VVTT method, and check it again with VVTT before it is cut on arrival:

• View the seal and the container's locking mechanisms
• Verify the seal number against the shipment documents
• Tug on the seal to make sure it is properly affixed
• Twist and turn the seal to make sure it does not unscrew

The same criteria call for a seal log, secure storage of unused seals, and, as applicable, reporting compromised seals to CBP and the appropriate foreign government.

When the seal is cut or does not match

• CBP exam: when officers open a container for a customs examination, they fit an ISO/PAS 17712 high-security bolt seal marked "CBP" with its own serial number and put the removed seal inside the container. A carrier may add its own seal but must not remove the CBP seal, and CBP notifies the carrier, broker or importer of the new number, sometimes by annotating the bill of lading
• At delivery: if the number on the seal differs from the documents, or the seal is damaged or missing, the box may have been opened in transit. The CTU Code says to contact the container operator, and a CBP-marked seal with a new number usually explains the difference

For full-container bookings, see FCL ocean freight.