In its final days, the Bush administration is poised to exempt poultry farms from reporting how much ammonia and other noxious pollutants they are releasing into the air from the millions of tons of manure their flocks generate, according to Baltimore Sun.

The Environmental Protection Agency (EPA) has asked the federal Office of Management and Budget to give final approval to a rule that would exclude poultry farms from environmental reporting required of other industries. The budget office reviews all proposed federal regulations to see that their benefits justify their costs.

The exemption is being sought by the poultry industry, which argues that farmers should not be saddled with the burden of reporting what it contends are harmless releases of ammonia from their birds' waste.

Ammonia emissions from farms are 'extremely low and pose no risk to human health', according to a statement issued by the National Chicken Council.

However, environmentalists counter that reporting is warranted because far more ammonia is getting into the air from poultry farms than from sewage treatment plants and other industrial sources - which do have to report their emissions.

What is more, ammonia contains nitrogen, one of the main pollutants fouling the Chesapeake Bay.

"Ammonia has the same health impacts, whether it comes from a steel mill or a chicken house," said Ed Hopkins of the Sierra Club.

"We know that some of these facilities' toxic air emissions vastly exceed the health reporting threshold."

An analysis by the Environmental Integrity Project estimates that chicken farms in Maryland release more than 20 million pounds of the noxious chemical annually - more than 50 times what is reported by the state's industrial facilities.

With 295 million chickens raised last year - mainly on the Eastern Shore - Maryland's multimillion-dollar poultry industry had ammonia emissions that were the eighth-highest among poultry-producing states nationwide, according to the Washington-based environmental group.

The Maryland Department of the Environment estimates an even higher output of ammonia from the state's poultry farms and processing plants - 27 million pounds annually, the article continues.

Ammonia is a colourless gas with a strong odor that is contained in animal and human waste. It is widely used as a cleaning agent and in various industrial products, and because it is rich in nitrogen it is a common ingredient in fertilizer.

At high levels in air, it can irritate skin, eyes and throat, cause coughing and burn lungs and bronchial passages. In extreme cases, it can cause death. People with asthma may be more sensitive to breathing it than others, according to the federal Agency for Toxic Substances and Disease Registry.

The reporting rule, proposed by the EPA, is one of dozens of regulations that are pending. Activists contend that the Bush administration is rushing through several 'midnight regulations' affecting the environment before President-elect Barack Obama takes office.

If the rules take effect before Obama's inauguration on 20 January, they cannot be blocked by the incoming Democratic administration, and changing or repealing them could take years.

One such last-minute rule change - issued after getting final approval - eliminates a requirement for federal agencies to consult with independent scientists before approving projects or activities that might harm endangered species of plants and animals.

The poultry industry petitioned the EPA to exempt it from federal 'right to know' laws requiring it to report ammonia and other emissions.

The EPA responded last December with a proposal to exempt all livestock operations, including dairy, hog and cattle farms. The rule was sent to OMB on 24 October for final review and approval.

EPA spokesman Dave Ryan said that the exemption is still under review, and he did not know when or whether it would be cleared for adoption. If published in the Federal Register by 19 December, it would take effect in 30 days, just before Bush leaves office.

"It's a waste of everyone's time, a diversion of valuable resources from potentially life-threatening problems," Richard Lobb of the National Chicken Council said of the reporting requirement.

Farms are not being required to comply with the law, he said, but if they were, all that release 100 or more pounds a day of a hazardous substance would have to report.

The reports are meant to help emergency responders decide whether to dispatch crews to clean up spills and evacuate or treat people for exposure to hazardous substances, says the Baltimore Sun article.

"The typical farmer on the Eastern Shore does not know how much ammonia is being emitted from his house," Mr Lobb said. "To expect him to report and call the fire department is not realistic."

Environmentalists counter that the reporting requirements are not onerous - annual estimates would be acceptable - and that ammonia releases from poultry farms are in need of closer scrutiny, according to the newspaper.

Activists believe that publicly documenting the scope of the pollution would increase pressure to reduce it, either through government regulation or voluntary action.

Michele Merkel, Chesapeake coordinator of the Waterkeeper Alliance, said people who live near chicken houses have complained to her group of noxious odors and breathing problems.

Though the EPA has not set any air-quality standards for ammonia from farms, studies indicate that levels of the gas in the exhaust vents from barns can be higher than the workplace exposure limits set by the US Occupational Safety and Health Administration, according to Eric Schaeffer, a former EPA official who heads the nonprofit Environmental Integrity Project.

Mr Schaeffer said responsibility for filing the reports ought to fall on the poultry companies for which farmers raise chickens under contract.

"The reports themselves are pretty simple," he said. "Companies like Perdue and Allen Foods, they should be doing these."

The EPA launched a study of air pollution from poultry farms last year. Mr Ryan said results would not be available until sometime next year.

But other studies indicate farms are a major source of the gas, experts told Baltimore Sun.

"Agricultural emissions in general are the dominant source of ammonia," said Joseph R. Scudlark, a lab director at the University of Delaware who has studied ammonia emissions from poultry farms on the Delmarva Peninsula.

Ammonia releases contribute to the bay's woes because they add to the estuary's overdose of nutrients. Nitrogen and another fertilizing nutrient, phosphorus, spur vast growths of algae in the bay. As those floating microscopic plants die, sink and decompose on the bottom, they deplete the water of the oxygen that fish need to live.

As much as a third of the nitrogen fouling the water comes from the air, according to Lewis Linker of the EPA's Chesapeake Bay Program. While most of the nitrogen in air comes from coal-burning power plants or vehicle exhaust, about a third is from farms.

But in agricultural areas such as the Eastern Shore, ammonia from farms makes up the majority of nitrogen coming from the air, said Mr Linker. Nitrogen emissions from vehicles and power plants have declined in recent years as air pollution rules have tightened. Farm emissions, which are not regulated, have not changed.

"If we are serious about getting a handle on nitrogen loads to the bay, we need to be concerned about this potentially significant source of nitrogen emissions," said Ms Merkel.

"We're being blamed for everything on the bay, and we don't accept that," responded Mr Lobb of the National Chicken Council.

The Sierra Club's Hopkins said environmental groups met with federal budget officials in November and urged them not to allow the exemption.

"But every indication we've had is they are headed in that direction," he told Baltimore Sun. "We certainly hope they will reconsider."