Cleveland-Cliffs will indefinitely idle the cold-rolled and coated steel operations at its Stelco plant in Hamilton, Ontario, putting up to 500 workers at risk, in the latest fallout from US steel tariffs.

The company announced on September 28 that the wind-down begins October 9, with production concentrated at its Lake Erie Works in Nanticoke. The union estimates about 350 Hamilton jobs will go.

Cliffs blames US tariffs of up to 50% on Canadian steel imposed since June 2025, which it says crushed demand — down about 25% in the second quarter versus the 2024 average, and 10% in Canada. CEO Lourenco Goncalves insisted the decision was about market conditions, not money.

The announcement drew a furious response in Ottawa. Prime Minister Mark Carney accused the company of “betraying” workers and threatened legal action over binding five-year job commitments made when Cliffs acquired Stelco for C$3.4 billion in 2024. Industry Minister Mélanie Joly said the government would “use every lever” to defend the jobs.

The clash sets up a major test of whether Ottawa can enforce investment pledges from foreign buyers.