The League of Conservation Voters is up with its second television ad hammering former Rep. Bob Schaffer (R), who is running for Senate against Rep. Mark Udall (D).

In the 30-second spot, which is running statewide on broadcast television, the LCV takes aim at Schaffer for his ties to the oil and gas industry and for campaign contributions he has accepted from political action committees associated with the energy sector.

“When you look at Bob Schaffer’s résumé, one thing comes through: oil,” opens the ad’s voice-over. “In Congress, Bob Schaffer voted to give $13 billion in tax breaks to gas and Big Oil.”

The National Republican Senatorial Committee accused the LCV of mischaracterizing Schaffer’s record to score political points.

“The ads are nothing more than character assassination from outside liberal groups trying to decide for voters who they should elect,” NRSC spokeswoman Rebecca Fisher said.

Schaffer and Udall are running for the seat being vacated by Sen. Wayne Allard (R), who is retiring.