The Democratic Senatorial Campaign Committee continued its onslaught against Sen. Elizabeth Dole (R-N.C.) on Monday, releasing its next installment in a $6 million-plus television blitz that is now hitting the lawmaker on rising energy costs.

“She voted for billions in tax breaks for Big Oil,” the narrator says in the 30-second ad. Dole voted “against funding for alternative energy like wind and solar … [and] even tried to eliminate mileage standards.”

“On gas prices, she’s part of the problem,” the ad closes.

Dole, who skipped last week’s Republican National Convention in St. Paul, Minn., is locked in a surprisingly competitive race with state Sen. Kay Hagan (D), whose bid was recently embraced by DSCC Chairman Charles Schumer (N.Y.).

As the DSCC ad went up on the air Monday, Dole’s campaign accused Hagan of backtracking on her support for federal legislation that would trump North Carolina’s right-to-work laws.

“It’s bad enough that Kay Hagan is in the tank for big labor, which is her largest campaign contributor — trying to hide her true colors from North Carolinians is inexcusable,” Dole spokesman Dan McLagan said in a statement on Monday. “Trying to sneak into office as a Trojan horse for her big labor backers is a slap in the face to voters.”