OTTAWA / WASHINGTON — Canada’s retaliatory tariffs on U.S. products take effect at 12:01 a.m. Eastern Time on Tuesday, Sept. 8, 2026, deepening a trade war between the longtime allies after negotiations broke down last month, according to the Government of Canada’s Finance Department list and reporting by ABC News on Monday.

Ottawa is matching U.S. Section 338 and related duties dollar for dollar: counter-tariffs of 15%, 25%, and 50% on products covering about C$27.6 billion in imports from the United States, with individual rates tied to the matching U.S. levy on the same goods. Targeted sectors include steel, dairy, appliances, agricultural equipment, pulp and paper, and electronics. The measures apply only to U.S.-origin goods; cargo already in transit to Canada when the surtax begins is exempt, Finance Canada said.

ABC News reported Monday that the Canadian package targets hundreds of U.S. products — from aluminum foil and raincoats to cheese — amounting to nearly 6% of annual U.S. exports to Canada on 2025 Census Bureau figures. Border-state lawmakers, including Republican Sen. Susan Collins of Maine, have warned the dispute will hit local businesses and consumers.

President Donald Trump has repeatedly threatened escalation if Canadian tariffs proceed. On Monday afternoon he posted on Truth Social that Canada-based aerospace manufacturer Bombardier should be barred from U.S. sales unless it builds in America: “NO MORE SELLING BOMBARDIER IN THE UNITED STATES!” He claimed more than half of Bombardier’s revenue comes from U.S. buyers and accused Ottawa of blocking Gulfstream and U.S. banks — rhetoric that arrives as the midnight counter-tariff clock runs down.

Late last month Trump also vowed to raise tariffs from 25% to 50% on Canadian cars and auto parts beginning in January, and wrote that Canada is among “the worst Nations in the World to deal with.” Prime Minister Mark Carney has said Canada will match U.S. tariffs “dollar for dollar, rate for rate,” and last week rebuked Washington’s meme-and-shade diplomacy: “When the Americans stop doing memes, stop throwing shade and stop trying to be tough, and start being serious about having those discussions, we can have those discussions.”

In the first half of 2026 the U.S. exported about $175.8 billion in goods to Canada — roughly 14% of all U.S. exports — the Census Bureau figures cited by ABC show. Tit-for-tat duties still cover only a slice of that trade for now, but each round raises the cost of crossing a border that used to be treated as a shared supply chain, not a scoreboard.

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