For farmers, this stinks: Belching and gaseous cows and hogs could start costing them money if a federal proposal to charge fees for air-polluting animals becomes law.

Farmers so far are turning their noses up at the notion, which is one of several put forward by the Environmental Protection Agency after the U.S. Supreme Court ruled in 2007 that greenhouse gases emitted by belching and flatulence amounts to air pollution.

"This is one of the most ridiculous things the federal government has tried to do," said Alabama Agriculture Commissioner Ron Sparks, an outspoken opponent of the proposal.

It would require farms or ranches with more than 25 dairy cows, 50 beef cattle or 200 hogs to pay an annual fee of about $175 for each dairy cow, $87.50 per head of beef cattle and $20 for each hog.

The executive vice president of the Wyoming Farm Bureau Federation, Ken Hamilton, estimated the fee would cost owners of a modest-sized cattle ranch $30,000 to $40,000 a year. He said he has talked to a number of livestock owners about the proposals, and "all have said if the fees were carried out, it would bankrupt them."

Sparks said Wednesday he's worried the fee could be extended to chickens and other farm animals and cause more meat to be imported.

"We'll let other countries put food on our tables like they are putting gas in our cars. Other countries don't have the health standards we have," Sparks said.

EPA spokesman Nick Butterfield said the fee was proposed for farms with livestock operations that emit more than 100 tons of carbon emissions in a year and fall under federal Clean Air Act provisions.

Butterfield said the EPA has not taken a position on any of the proposals. But farmers from across the country have expressed outrage over the idea, both on Internet sites and in opinions sent to EPA during a public comment period that ended last week.

"It's something that really has a very big potential adverse impact for the livestock industry," said Rick Krause, the senior director of congressional relations for the American Farm Bureau Federation.

The fee would cover the cost of a permit for the livestock operations. While farmers say it would drive them out of business, an organization supporting the proposal hopes it forces the farms and ranches to switch to healthier crops.

"It makes perfect sense if you are looking for ways to cut down on meat consumption and recoup environmental losses," said Bruce Friedrich, a spokesman in Washington for People for the Ethical Treatment of Animals.

"We certainly support making factory farms pay their fair share," he said.

U.S. Rep. Robert Aderholt, a Republican from Haleyville in northwest Alabama, said he has spoken with EPA officials and doesn't believe the cow tax is a serious proposal that will ever be adopted by the agency.

"Who comes up with this kind of stuff?" said Perry Mobley, director of the Alabama Farmers Federation's beef division. "It seems there is an ulterior motive, to destroy livestock farms. This would certainly put them out of business."

Butterfield said the EPA is reviewing the public comments and didn't have a timetable for the next steps.