GREENSBORO - William LeCompte sped in a golf cart alongside a windowless steel building nearly twice the length of a football field, packed with 28,000 chickens and monitored by computers that calibrate their food, water, heat, lighting and air.
At the end of the immense, hangar-like structure, he pointed to a vent framing a 4-foot-high fan, whose whirling blades breathed a warm, moist plume of fetid gas into the night sky over Maryland's Eastern Shore. "Smells like money to me," he said as the reek washed over him.
Air pollution from large, indoor animal-feeding operations such as LeCompte's are at the center of a national debate over whether the federal government should treat some farms like factories by demanding exhaust-filtration systems.
LeCompte and other farmers argue that it's "crazy" for the U.S. Environmental Protection Agency to try to aim at chickens the same federal laws - the Clean Air Act and the Superfund law - intended for oil refineries and toxic waste dumps.
But environmentalists argue that farm pollution is the "silent killer" of the Chesapeake Bay and other bodies of water, and that the government should help limit both the runoff of fertilizer from fields and the evaporation of ammonia and sewer gas from manure.
"We are dealing with a major health threat - this is not a benign issue," said William Becker, executive director of the State and Territorial Air Pollution Program Administrators, a Washington nonprofit group.
After the passage of the 1970 federal Clean Air Act, the EPA during much of the 1970s and 1980s did not consider farms to be major enough sources of air pollution to be held subject to the law.
But the size of indoor animal-feeding operations exploded during the 1980s and 1990s. By the end of the 1990s, the agency switched directions and began to file Clean Air Act enforcement actions against large farms in Missouri and Ohio.
Fearing these lawsuits, a "barnyard coalition" of farm lobbyists, as some call themselves, asked the Bush administration for an amnesty deal, said Michele Merkel, a former EPA enforcement attorney who is an environmental activist.
The amnesty agreement announced by the EPA last month will exempt farms from air pollution enforcement for at least four years while researchers conduct a national survey of the problem. After that, the EPA may require air permits for farms and enforce pollution limits, agency officials said.
The agreement offered was exactly what the farm lobby requested, Merkel said, and amounts to a stalling tactic that will halt enforcement for almost a decade.
"In the beginning of the Bush administration, I was told we can't pursue any more Clean Air Act violations against animal-feeding operations, and all water enforcement against them also slowed to a halt," said Merkel. "It was incredibly frustrating, because the EPA staff was asked not to touch an entire industrial sector," said Merkel, who quit in protest in February 2002.
Researchers have long known that livestock in the bay's watershed produce about 44 million tons of manure a year, with much of it being washed by rain from fields into the bay, where it creates "dead zones" in the Chesapeake.
To help discourage the excessive use of fertilizer, the state in 1998 began requiring farms to write nutrient management plans, and about two-thirds have complied. This runoff-control planning system is sometimes criticized as weak, because it lacks teeth (no farmer has ever been fined for failing to submit a plan) and the farmers monitor themselves.
But an effort is under way to address the problem, which is not true with air pollution from chicken houses, environmentalists say.
In an effort to understand this little-recognized part of the problem, Ronald L. Siefert and four other researchers at the universities of Maryland and Delaware recently calculated the extent to which ammonia rising from large indoor animal-feeding businesses contributes to regional air pollution.
The 587 million chickens in 2,100 farms in the Delmarva peninsula emit 20,000 tons of ammonia gas a year, Siefert estimates. That's about 10 percent of all the nitrogen air pollution pouring from cars, factories and other sources in the region.
Ammonia in the atmosphere gets washed by rain into streams and waterways that flow into the Chesapeake Bay, and this form of nitrogen feeds algae that bloom and then quickly die. The process consumes so much oxygen that "dead zones" spread in which fish, crabs and oysters can't breathe, Siefert said. About 27 percent of the nitrogen in the bay drifts down from the atmosphere, and about 38 percent of the bay last summer was a "dead zone," according to the Chesapeake Bay Foundation.