The League of Conservation Voters named U.S. Sen. Elizabeth Dole to its "Dirty Dozen."

The advocacy group tracks members of Congress on its scorecard of votes on environmental issues, but it periodically issues a list of what it considers the 12 worst.

"Senator Dole's record proves that she's working in the best interests of Exxon-Mobil, not the people of Raleigh-Durham," said political director Tony Massaro in a statement.

The group has given Dole a lifetime rating of four percent on its environmental scorecard for votes against incentives for renewable energy and for tax breaks for oil companies.  

In 2006, the League of Conservation Voters named then U.S. Rep. Charles Taylor to the "Dirty Dozen" and spent money advertising against him. Taylor lost the election.

Massaro would not say if the league will spend money on Dole's race.