"A beef industry group has challenged a ruling by U.S. environmental regulators that greenhouse gas emissions endanger human health, saying the move would hurt agriculture.

The ruling earlier this month by the Environmental Protection Agency earlier opens the way for regulation of six heat-trapping gases without new laws passed by Congress.

Livestock farms emit carbon dioxide from the tailpipes of machinery and trucks, while waste from cattle also emits methane, a powerful greenhouse gas.

The National Cattlemen's Beef Association filed a petition in the D.C. Circuit Court of Appeals this week, saying EPA climate regulations would hurt large farms."

Timothy Gardner reports for Reuters December 30, 2009. [2]