U.S. Customs and Border Protection (CBP) recently issued guidance via the Cargo Systems Messaging Service (CSMS) on filing entries for imports from Canada subject to duties under Section 338 of the Tariff Act of 1930 (Section 338). We previously covered President Trump’s imposition and subsequent modification of these Section 338 tariffs here, here, and here.

Specifically, on September 11, 2026, CBP clarified which classifications under the Harmonized Tariff Schedule of the United States (HTSUS) are subject to Section 338 duties as of September 15, 2026. A complete list of those HTSUS classifications can be found here.

Per the CSMS, the following HTSUS classifications corresponding to HTSUS 9903.03.12 and 9903.03.14 are no longer subject to Section 338 duties:

• For HTSUS 9903.03.12: 2208.30.60 and 2208.70.00.
• For HTSUS 9903.03.14: 2501.00.00, 2523.29.00, 2940.00.60, 4803.00.40, 4818.90.00, 7801.10.00, 8537.10.91, and 9507.10.00.

Finally, the CSMS clarified that, as of September 15, 2026, only goods subject to HTSUS 9903.03.13 are eligible to claim HTSUS 9903.03.15, which provides for a 0% duty rate under Section 338 and applies to the following articles:

• Articles of aluminum, of steel or of copper or derivative aluminum or steel articles; passenger vehicles (sedans, sport utility vehicles, crossover utility vehicles, minivans and cargo vans) and light trucks; parts of passenger vehicles (sedans, sport utility vehicles, crossover utility vehicles, minivans and cargo vans) and light trucks; medium- and heavy duty vehicles; parts of medium- and heavy duty vehicles; wood products; semiconductor articles; and patented pharmaceutical articles, as provided in subdivision (c) of U.S. note 51.

The Husch Blackwell International Trade and Supply Chain team will continue to monitor and provide updates on this investigation as they become available. If you have company specific questions or concerns, please contact your Husch Blackwell attorney.