Although Nucor has excelled in its work practices, until a few years ago, it was far from a role model in environmentalism. A dozen years ago, Nucor paid the largest environmental settlement by a steel company in the United States for allegedly failing to control the emission of toxic chemicals in several U.S. states. It was also identified as the 14th highest contributor to air pollution in the United States. Nucor responded to these concerns by hiring environmental staff and introducing new technologies, with the result that its emissions and energy use have fallen dramatically. For example, the company's new ultra-thin cast strip process consumes 85 percent less energy than a conventional mill with a 75 percent reduction in greenhouse gas emissions.