Some U.S. steel and aluminum makers are restarting idle mills and boosting capacity to make up for imports that face being priced out of the market if President Donald Trump’s proposed import tariffs take hold.

United States Steel Corp. on Wednesday said it would fire up a blast furnace in Granite City, Ill., and call back 500 workers. Century Aluminum Co. said last week it will restart lines at a smelter in Kentucky that have been curtailed since 2015, doubling its workforce there to 600.

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