The Environmental Protection Agency must take cost into account when determining whether to regulate toxic air pollutants emitted from power plants, the US Supreme Court ruled on Monday. In a 5-to-4 decision, the high court said the agency improperly streamlined the regulation process required under the Clean Air Act when it decided to consider only public health hazards in making the initial decision to restrict power plant emissions. EPA’s rule set new standards for emissions of mercury and other toxic substances from some 600 oil- and coal-fired electric power plants mostly in the upper Midwest and the South.
