U.S. President Donald Trump’s heightened tariffs on steel and aluminum coming into his country will “create mass disruption and negative consequences,” Canada’s steel industry warns.

Trump said on Friday that he will double the tariffs on steel and aluminum imports to 50 per cent.

Catherine Cobden, president and CEO of the Canadian Steel Producers Association (CSPA), said the steel industry in Canada and the U.S. were highly integrated and tariffs would hit steel producers on both sides.

“Steel tariffs at this level will create mass disruption and negative consequences across our highly integrated steel supply chains and customers on both sides of the border,” Cobden said in a statement Saturday.

The tariff increase will take effect Wednesday, Trump said in a Truth Social post shortly after he announced the new rate for steel imports at a rally with steelworkers in Pennsylvania.

“Our steel and aluminum industries are coming back like never before. This will be yet another BIG jolt of great news for our wonderful steel and aluminum workers,” Trump wrote.

Cobden said the move “essentially closes the US market to our domestic industry for half of its production.”

“It is vital that the Government of Canada responds immediately to fully re-instate retaliatory steel tariffs to match the American tariffs and to implement as quickly as possible new tariffs at our own borders to stop unfairly traded steel from entering Canada,” she said.

She said a trade war between Canada and the U.S. would “have unrecoverable consequences” on the North American steel industry.

“The new government has already consulted on possible new measures. The time for the Canadian government to act is now,” she said.

Trump announced the increased duties on steel during a rally at U.S. Steel’s Mon Valley Works–Irvin Plant near Pittsburgh Friday evening, where he criticized countries for “dumping” their “garbage” steel products into the U.S. at a lower cost.

“We are going to bring it from 25 per cent to 50 per cent the tariffs on steel into the United States of America, which will even further secure the steel industry in the United States,” Trump told the crowd.

“Nobody is going to get around that.”

In March, Trump put 25 per cent tariffs on steel and aluminum imports to the United States. The president has said his sweeping tariffs will bring manufacturing back to the United States.