HARRISBURG, Pa. (AP) — The fatal explosion last week at U.S. Steel's Pittsburgh-area coal-processing plant has revived debate about its future just as the iconic American company was emerging from a long period of uncertainty.

The mill, which is part of the recent merger between U.S. Steel and Nippon Steel, has faced scrutiny from federal and local regulators.

The fortunes of steelmaking in the U.S. – along with profits, share prices and steel prices – have been buoyed by years of friendly administrations in Washington that slapped tariffs on foreign imports and bolstered the industry’s anti-competitive trade cases against China.