EPA’s limits on industrial emissions of greenhouse gases, include carbon dioxide are illegal and must be thrown out, opponents told federal judges in Washington on Wednesday.  A three-judge panel of the U.S. Court of Appeals this week considered challenges to the agency’s rules determining which polluters are covered and when states and industries must comply with regulations curtailing the use of greenhouse gases.

EPA crossed the line from statutory interpretation to statutory revision, Peter Keisler, a lawyer for the national Association of Manufacturers, told the judges.  He said EPA violated the law when the agency raised emissions thresholds far above what Congress called for. Corporations, business groups including the U.S. Chamber of Commerce, and states led by Texas and Virginia are seeking to stop the agency through more than 60 lawsuits.  Some argue that the agency relied on biased data from outside scientists.

The panel of judges heard arguments this week on the agency’s finding that greenhouse gases are pollutants that endanger human health.  They also heard arguments against a 2010 rule on motor vehicle emissions that opponents said improperly sets greenhouse-gas standards for stationary sources, such as steel mills and power plants.

The court considered challenges to EPA’s “tailoring rule,” which limits the businesses covered by carbon regulation. The agency aims to phase in industrial polluters covered by the carbon rules through 2016, arguing in court filings that the tailoring rule is acceptable under the Clean Air Act and necessary to avoid states being overrun with permit request.

In 2007, the Supreme Court ruled that EPA had authority to regulate greenhouse gases such as carbon dioxide and methane under the Clean Air Act, if the agency declared them a public danger.  EPA issued an “endangerment finding” in December 2009, clearing the way for regulations of emissions from power plants, factories, and other sources linked to global climate change.