Container Seal

What it means

CBP's CTPAT security criteria require shipments that can be sealed to be secured immediately after loading, by the shipper or the packer acting for the shipper, with a high-security seal that "meets or exceeds the most current International Organization for Standardization (ISO) 17712 standard."^[1] The seal number is recorded on the shipping documents.

ISO 17712 sets uniform procedures for classifying, accepting and withdrawing mechanical freight container seals. The edition in force is ISO 17712:2013, which ISO last reviewed and confirmed in 2023.^[2]

CTPAT teaches a four-step check, VVTT: view the seal and locking mechanisms, verify the seal number against the documents, tug the seal, and twist and turn a bolt seal to be sure it does not unscrew. For discrepancies it says to keep altered or tampered seals, investigate, and report compromised seals to CBP as applicable.^[1]

Seal classes and seal types

ISO 17712 rates seals by strength in three classes: I (indicative), S (security) and H (high security). CTPAT accepts only H class. A seal's class has to be confirmed by an independent test laboratory accredited to ISO/IEC 17025, the seal maker's security practices are audited against the standard's Annex A, and the seal must show tell-tale evidence when someone tries to defeat it after it is closed.^[3]

• Bolt seal. A bolt pushed through the door hasp and locked into a barrel. CTPAT recommends fitting it with the barrel facing up, above the hasp, and the VVTT twist step is written for bolt seals.^[1]
• Cable seal. A cable wrapped around the base of the door locking bars and pulled through a locking body. CTPAT says all slack must be removed and the check confirms the cable is taut and does not slip in the body.^[1]
• Both count. CTPAT accepts qualifying cable and bolt seals alike; what matters is the H class certification. Members that buy seals keep a copy of the laboratory test certificate as proof.^[1]

Where the seal goes and where the number is recorded

CTPAT places the seal on the secure cam position when the door has one, instead of the right door handle, at the bottom of the center-most locking bar of the right-hand door. Without a secure cam, the seal can go on the center-most left-hand locking handle of the right door.^[1]

The number then travels with the paperwork. CBP guidance asks shippers to print the seal number electronically on the bill of lading or other shipping documents, and to send it to the consignee before the box leaves.^[4] For ocean imports, the seal numbers for all seals on a container are among the data the vessel carrier's cargo declaration must give CBP.^[5] At Port Newark, PNCT reminds shippers to fit an ISO 17712:2013 high-security seal to every full container and to record the seal number accurately on the shipping instructions before the box comes to the terminal.^[6]

Who handles the seal along the way

• Shipper or packer. Keeps seals in secure storage with access limited to authorized staff, logs them on receipt and on issue, and has a trained, designated person apply the seal with a second person witnessing.^[4]
• Trucker. On pickup, and after any stop, checks that the seal is intact and that the number matches the shipping documents.^[1]
• Customs. CBP or a foreign customs authority may cut the seal to examine the cargo. A new seal goes on, and the replacement number has to be recorded; the driver tells dispatch who broke the seal and the new number.^[1]
• Receiver. Under CBP's recommended procedures for importers, runs the VVTT check with a witness before cutting the seal, then keeps cut seals in a separate container that others cannot get into until they are destroyed.^[7]

Why it matters

Under shipper load and count terms nobody else counted the freight, so an intact seal with a matching number is the receiver's evidence that the doors stayed closed between the shipper's dock and its own. That is why the seal is checked and photographed before it is cut, and why the number should be on the bill of lading before the box reaches the port. A dock that is unloading a container needs the expected seal number with the delivery appointment, or there is nothing to verify at the door.

Example

A receiver checks the bolt seal on an arriving container: it is intact, the number matches the bill of lading, and it does not turn when twisted. The number and a photo are logged before the seal is cut.

Common confusions

• Seal number vs. container number. The container number identifies the box itself. The seal number identifies one seal, and it changes whenever a seal is cut and replaced.
• A new seal number is not always a problem. After a customs exam the box carries a replacement seal; CTPAT expects the carrier to notify the shipper, broker and importer of the change, and the shipper to note the new number in its seal log.^[1] A mismatch with no recorded reason is a different matter: see what to do when a seal is broken or does not match.
• Intact seal, damaged freight. A good seal shows the doors stayed closed. It says nothing about how the load was packed or braced, so damage found inside is handled as a freight damage claim, with the seal photos as part of the record.
• Seal vs. lock. A seal is a one-time device made to show tampering, not to be opened and closed again. Once cut, CBP's recommended procedures put it in a secured container for destruction.^[7]

Frequently asked questions