Sixteen states have filed a petition June 19 in a federal appeals court, challenging the federal government´s Clean Air Mercury Rule.

The U.S. Environmental Protection Agency Rule would cap and reduce mercury emissions from coal-fired power plants by 70 percent over 2000 levels. In the first phase, the rule would cap annual mercury emissions at 38 tons by 2010. The second-phase cap is 15 tons per year by 2018, when the program is fully implemented.

U.S. coal-fired power plants annually emit about 48 tons of mercury.

But the rule does not go far enough, according to the states filing the petition in the U.S. Court of Appeals for the District of Columbia Circuit. The EPA´s program delays mercury emission cuts and would create hot spots of mercury contamination, according to their complaint.

The states also are challenging a separate rule that removed power plants from the list of pollution sources subject to stringent pollution controls under the Clean Air Act. The states contend that requiring coal-fired plants to comply with the Clean Air Act would reduce mercury emissions deeper and quicker.

The states originally filed the lawsuit last year, but the court put the case on hold in October when the EPA agreed to formally reconsider the rules.

On May 31, the EPA issued its final rule and published it June 9, prompting the states to file their June 19 petition to move forward with the lawsuit.

The states involved in the lawsuit are California, Connecticut, Delaware, Illinois, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Pennsylvania, Rhode Island, Vermont and Wisconsin.