WASHINGTON - The Environmental Protection Agency has concluded that carbon dioxide and five other greenhouse gases are a danger to public health and welfare. It is the first step to regulating pollution linked to climate change.

Congressional sources told The Associated Press that EPA will announce its proposed finding today and begin a comment period before issuing a final ruling. The EPA also will say tailpipe emissions from motor vehicles contribute to climate change. The officials spoke on condition of anonymity because the finding hasn't been announced.

The action was prompted by a Supreme Court ruling two years that said greenhouse gases are pollutants under the Clean Air Act and must be regulated if found to be a human health danger.