In a precedent-setting move, U.S. federal officials signed an agreement yesterday ceding control of the cleanup of Idaho’s highly polluted Coeur d’Alene Basin to state, local, and tribal officials. For more than a century, mining waste from the Silver Valley washed down the Coeur d’Alene River into Lake Coeur d’Alene and the Spokane River, and from there into Lake Roosevelt, where fish have shown elevated levels of mercury and other toxins. The cleanup of the area, one of the nation’s largest Superfund sites, has long been a contentious issue, with locals fearing that extensive U.S. EPA involvement would create negative publicity and harm the local economy. The transfer of authority could mitigate that problem, but environmentalists view the move with suspicion because the same state officials who downplayed the need for a cleanup in the past will now decide how to proceed. Many residents of Washington state, which is also affected by the pollution, have criticized the transfer of authority as well.