23 states, multiple coal companies ask Supreme Court to halt Biden rule to restrict pollution

Twenty-three Republican-led states and at least two coal companies are asking the Supreme Court to halt a Biden administration rule that seeks to limit power plants’ emissions of mercury and other toxic metals. 

The rule in question tightens emissions limits for toxic substances such as lead and arsenic by 67 percent. For some coal plants with historically looser mercury controls, the rule tightens mercury limits by 70 percent. 

Exposure to substances regulated under the rule...