"Is Toyota a wolf in sheep's clothing?"

That's the suggestion of a stinging national ad campaign against Toyota Motor Corp., launched today by a San Francisco-based environmental group. The ad is to run in Mother Jones online today and be printed soon in full-page ads in the New York Times and other publications.

Created by the Bluewater Network, a nonprofit organization that fights for clean air and water, the ads against Toyota are thought to be the first ever to attack a Japanese automaker on its environmental record in the United States.

Bluewater says Toyota's hybrids aren't as efficient as their nonhybrid versions and questions why the automaker is fighting tougher standards on fuel economy and emissions. They also note that while Toyota's overall fuel economy is the best in the industry, it is worse than it was 20 years ago, according to the U.S. Environmental Protection Agency.

Toyota spokeswoman Nancy Hubbell said the automaker is disappointed by the campaign. "Toyota is definitely the environmental leader, and we're extremely surprised," she said.

Bluewater is the same environmental group that launched a personal ad campaign against Ford Motor Co. last year, portraying Ford Chairman and Chief Executive Officer Bill Ford as Pinocchio and challenging the automaker's record on environmental issues.

Those ads, according to Bluewater, were largely a consequence of Ford portraying himself as an environmentalist, making promises and not keeping them.

Now, Bluewater is taking on Toyota.

"We don't enjoy playing the truth squad," Danielle Fugere, director of climate change at Bluewater, said. "But when the auto industry misleads the public, whether intentionally or not, someone's got to set the record straight."

The ads against Toyota are likely to be heralded by Detroit automakers, which have been crying foul for years now over Toyota's seemingly bulletproof image with consumers as the environmentally friendly automaker.

Toyota makes one-third of the hybrid gasoline-electric vehicles sold in the United States and has consequently benefited from Earth-friendly buzz — even getting A-list celebrities to arrive at the Academy Awards in hybrid Prius compact cars as an environmentally conscious fashion statement.

But Bluewater's ads, which were obtained by the Free Press last week, show Toyota CEO Katsuaki Watanabe in the foreground and a man wearing a wolf head in the background. The ads list a series of concerns about Toyota.

Foremost, the group questions why Toyota's newest hybrids don't get much better fuel economy than their nonhybrid versions.

The hybrid version of the Highlander got only 20.6 miles per gallon in a week-long test drive this year on a range of driving conditions by Free Press auto critic Mark Phelan. The EPA rating shows the vehicle gets 33 mpg city/28 mpg highway in federal tests. The nonhybrid Highlander, meanwhile, was rated 19 mpg city/25 mpg highway by the EPA -much closer to the actual results in the hybrid.

Other journalists have found similar results, Bluewater notes in its ad, calling the Highlander and Lexus RX 400h "gas guzzlers with no better fuel economy than their nonhybrid versions."

The ad continues. "If this is the precedent for Toyota's future hybrids, that will be bad news for global warming and our dependence on foreign oil."

Hubbell of Toyota defended the company's hybrid vehicles, saying they are more efficient than their gasoline counterparts.

What's more, she said they are 80 percent cleaner in emissions.

Bluewater also asks why Toyota is working with other automakers to resist federal efforts to raise national fuel mileage standards and suing to block California's proposed regulations to reduce smog and greenhouse gas pollution.

Hubbell said Toyota is lobbying for regulations that are "rational and national," to avoid a patchwork system of standards "that would be a nightmare" for manufacturers to comply with.

The ads also note that the average fuel mileage of Toyota vehicles is worse today than it was 20 years ago, according to the environmental agency's 2005 Fuel Economy Trends report. In 2005, Toyota's fleet averaged 27.5 miles per gallon, the highest among manufacturers. But the company performed better in 1985, with its fleet averaging 30.0 miles per gallon, the report shows.

While Toyota has a stable of fuel-efficient cars, including the hybrid Prius, it also makes the Land Cruiser SUV (17 mpg on the highway); Sequoia SUV (18 mpg); 4Runner SUV (21 mpg), and Tundra Double Cab (18 mpg). Those vehicles have helped lower Toyota's overall fuel economy.

"Toyota has a lot of explaining to do," Bluewater's ads say. "We thought Toyota cared about the environment. ... Is this the same company that brought us the hybrid Prius, claiming to be an environmental leader?"

The ads provide Toyota's telephone number and encourage consumers to call and ask Toyota to "build more fuel-efficient cars and end Toyota's opposition to critical U.S. environmental policies."