CBP provided final guidance on September 8, 2026 modifications to Section 338 additional duties on certain Canadian goods.

A Section 338 measure is a U.S. trade action authorized under Section 338 of the Tariff Act of 1930. It can impose additional duties on imported goods from a specified country when the legal requirements for that action are met. The extra charge is generally applied in addition to the normal tariff and other applicable import fees.

These measures typically affect importers, customs brokers, and sellers bringing covered goods into the United States from the named country. Whether a shipment is covered depends on factors such as the product’s Harmonized Tariff Schedule of the United States (HTSUS) classification, country of origin, entry or withdrawal timing, and any exclusions or special instructions in the official measure. CBP guidance explains how to report and administer the measure, but the importer remains responsible for accurate entry information and duty payment.

What to check

• Confirm the product’s HTSUS classification, using the complete tariff provision rather than relying only on a product description or commercial invoice.
• Verify the product’s country of origin under U.S. origin rules; the shipping country and the origin country are not always the same.
• Check the official Section 338 measure and CBP guidance for the covered tariff provisions, exclusions, reporting instructions, and effective-entry rules.
• Ask your customs broker or trade counsel to review treatment when the product is substantially transformed, assembled in multiple countries, or potentially covered by more than one additional duty.
• Keep supporting records, including product specifications, manufacturing details, origin documentation, classification analysis, and entry calculations.