More than two decades ago, research from the 3M company showed the U.S. Environmental Protection Agency, or EPA, that sewage sludge, the raw material used for fertilizer, carried toxic “forever chemicals.” Since then, Rolf Halden, a professor in the School of Sustainable Engineering and the Built Environment, part of the Fulton Schools, and a leading researcher of contamination in biosolids, met with EPA officials multiple times to warn that his research drew the same conclusion. These sludge materials continued to be used, including by farmers for growing crops. Over the years, however, more concerns were raised about unheeded warnings of the health and environmental dangers. Research by Halden and others eventually helped to lead to wastewater testing to help track the problem and make the case for more precautions.