Murray Energy called the ozone rule “exorbitantly expensive, illegal, and job-killing.” The rule, which was published in the Federal Register on Monday, decreases the limit for ozone emissions from 75 parts per billion to 70 parts per billion.

“This ozone rule is yet another illegal and destructive action aimed at killing these jobs,” said Robert Murray, chairman, president, and chief executive officer of Murray Energy. We have the law, science, economics, cold hard energy facts, and the Constitution on our side. We will continue to fight to preserve our jobs and livelihoods, and we will prevail in our litigation.”