Rhode Island, which has one of the highest rates of child lead poisoning in the nation, is suing some of the biggest names in U.S. manufacturing, including DuPont Co., the nation's No. 1 chemical company, and Sherwin-Williams Co., the No. 1 paint maker. Other defendants include Atlantic Richfield, which was acquired by BP Plc, Cytec Industries, NL Industries Inc. and a unit of ConAgra Foods.