The dollar-for-dollar tariffs went into effect as scheduled, alongside a $7.5 billion aid package for the industries hit hardest.

Canada's counter-tariffs on U.S. goods took effect at 12:01 a.m. on September 8, as scheduled, applying rates of 15%, 25% or 50% across roughly $27.6 billion in American imports. The measures cover more than 700 tariff lines, with steel and aluminum products facing the steepest 50% surcharge, dairy and appliances at 25%, and electronics facing the lightest hit at 15%.

What actually landed

The government confirmed the new measures stack alongside, rather than replace, Canada's existing counter-tariffs on U.S. autos from the earlier round of the trade dispute. Goods already in transit to Canada on September 8 were exempted from the new rates, giving importers who'd already shipped some breathing room, but anything ordered or shipped after that date is subject to the full new schedule.

Alongside the tariffs, Ottawa rolled out a roughly $7.5 billion aid package aimed at industries most exposed to the trade escalation — a signal that the government expects the standoff to extend rather than resolve quickly, and is trying to cushion the domestic cost of its own retaliatory measures rather than betting on a fast return to negotiations.

What it means now that it's live

For businesses that spent the run-up to September 8 pulling forward U.S. orders or lining up alternate suppliers, the calculus is now permanent rather than provisional — there's no indicated end date for either set of measures. If you haven't yet checked your supply chain against the government's full tariff-item list, that's still the first practical step, since the categories affected are broader than the six headline sectors suggest, running to over 700 individual tariff lines covering everything from cosmetics to sporting goods.