LCV, which ranks lawmakers’ voting records on the environment, gives Allen a 1 percent lifetime score on its national environmental scorecard.
“George Allen has spent his time out of office working for his favorite oil executives and now he’s trying to return to the U.S. Senate to make all their legislative dreams come true,” Navin Nayak, senior vice president of campaigns at LCV, said in a statement.
“We’ve seen this movie before and know how it ends: as Senator, George Allen can only be counted on to champion special interests, not the public interest.”
LCV and Sierra Club have the environmental movement's biggest political operations. Allen's placement on the "Dirty Dozen" list signals that LCV hopes to keep a Democrat in the seat in a year that’s expected to see GOP gains.
Virginia is a battleground state that President Obama won in 2008, but that Republicans see as a place to gain a Senate seat and swing back into the GOP column in the 2012 presidential race. The Cook Political Report calls the Virginia Senate race a "toss-up."
LCV has placed 12 lawmakers whom the group says have the worst environmental record on its yearly list. Allen is the first lawmaker LCV has placed on the list this year.
—Ben Geman contributed.
This post was updated at 2:20 p.m.