A federal appeals court has ruled that the Bush administration doesn't have to speed up a decision on whether greenhouse gases blamed for global warming threaten public health.

The U.S. Court of Appeals for the District of Columbia denied a petition by numerous states and environmental groups that asked the court to order the Environmental Protection Agency to make that determination within 60 days.

Such a finding is a necessary first step to begin regulating carbon dioxide and other greenhouse gases from motor vehicle tailpipes and from the smokestacks of refineries, power plants and factories. The Supreme Court a year ago ruled that the EPA has the authority to regulate greenhouse gases under the Clean Air Act, a step Bush has repeatedly refused to take.