U.S. Supreme Court justices signaled they are divided over Obama administration rules that would cut emissions from 460 coal-fired power plants in an effort to curb birth defects, heart disease and premature deaths. During arguments Wednesday, justices questioned Environmental Protection Agency controls on mercury and acid gases from the plants owned by Southern Co., American Electric Power Co. and other utilities. Lawyers for power companies and some states said the agency didn’t adequately consider costs before imposing rules estimated to cost $9.6 billion a year. “It’s classic arbitrary and capricious agency action,” Justice Antonin Scalia said, referring to a legal standard the court can use to block an agency rule. The Obama administration says it considered costs in how it set the rules but wasn’t required to do so at the initial stage of deciding whether to issue regulations at all. That argument was questioned by Scalia […]