HARRISBURG, Pa. (AP) — The fatal explosion last week at U.S. Steel's Pittsburgh-area coal-processing plant has revived debate ...

The air monitor generates a beam of infrared light, shoots it down to that mirror, which causes it to bounce back.

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 p ...