The Supreme Court ruled Monday against the Obama administration's attempt to limit power plant emissions of mercury and other hazardous air pollutants, but it may only be a temporary setback for regulators.
The justices split 5-4 along ideological lines to rule that the Environmental Protection Agency did not properly take costs into account when it first decided to regulate the toxic emissions from coal- and oil-fired plants.
The EPA did factor in costs at a later stage, when it wrote standards that are expected to reduce the toxic emissions by 90 percent. But the court said that was too late.
Maryland power plants already have slashed their mercury emissions to...