The 50% additional duties that the United States imposed on certain Canadian goods under section 338 of the Tariff Act of 1930 came into force at 12:01 a.m. eastern time on Saturday, August 22, 2026. They had been scheduled for August 19. On August 18, Proclamation 11056 suspended them for three days, moving the effective date in each of the three July 20 proclamations (motor vehicles, dairy and alcoholic beverages) to August 22 and directing U.S. Customs and Border Protection to suspend collection and refund anything collected in the interim. The proclamation gave the reason: senior officials advised that Canada had “expressed a commitment to remove the discriminations” at issue and that the status of negotiations justified a short pause. The negotiations concluded on Friday, August 21 without an agreement, and the duties applied as rescheduled the next morning.
What is covered
The three proclamations are titled by sector, but their scope is the list of HTSUS subheadings in Annex II of each, which is broader than the sector names suggest. The Department of Finance Canada describes the U.S. action as a 50% tariff on approximately $27.6 billion of Canadian goods. The duty is additional to any other duty that applies, and it attaches to goods entered for consumption, or withdrawn from warehouse for consumption, on or after the effective time. The proclamations contain no exemption for goods that qualify as originating under CUSMA: a Canadian product that has crossed duty-free under the agreement for six years pays the 50% if its subheading is in Annex II. The only carve-outs are articles already subject to Section 232 duties and civil aircraft covered by the WTO aircraft agreement. Section 338 caps additional duties at 50% ad valorem, and it also allows the President to suspend, revoke, supplement or amend a proclamation whenever the public interest requires, which is the mechanism used for the three-day pause and which remains available.
Practical impact for exporters: any shipment entered into the U.S. from August 22 onward should be checked against the Annex II subheadings, not against a product description, and a valid CUSMA certification does not change the answer. Exporters who shipped during August 19 to 21 and paid the duty are entitled to a refund under the proclamation, processed through CBP’s standard refund procedures; confirm with your U.S. broker that the entries have been flagged.
What comes next on the Canadian side
The Prime Minister said on August 22 that Canada would respond with counter-tariffs matching the U.S. measures, to take effect on September 8, 2026, concentrated in sectors such as steel, dairy, appliances, agricultural equipment, pulp and paper and electronics. We will publish the details once the Department of Finance releases the product list and the CBSA issues its customs notice.
Read Proclamation 11056 in the Federal Register · Motor vehicles proclamation (July 20) · Dairy proclamation · Alcoholic beverages proclamation
