Sen. John Edwards, D-N.C., argued strongly against the idea in a letter to EPA Administrator Christine Todd Whitman and indicated he would file legislation to block any potential deal. The New York Times first reported news of the proposed amnesty deal earlier this month, and environmental groups have since distributed copies of the once-confidential agreement that the livestock industries proposed to the EPA. In exchange for what would be unprecedented immunity, the industry would pay for an $11 million program in which federal regulators would monitor pollution levels at about 30 farms. Though the number of farms that would be monitored is small, all producers that sign the deal — potentially thousands of large industrial-style hog and chicken operations — would be granted amnesty for the duration of the multiyear study, as well as for past infractions, Edwards and the environmental groups say. "These actions threaten the quality of life and air for thousands of rural families across America," Edwards wrote to Whitman in a letter released by his office. "It is stunning to me that your agency is contemplating a sweeping grant of amnesty that not only eliminates federal clean air protections, but also takes away the rights of states and communities to protect themselves." Mike Briggs, a spokesman for Edwards, said the senator had not received any response from Whitman EPA officials could not be reached for comment. Lobbyists for the meat producers say that the proposal has been misconstrued in media reports and that it is a good-faith effort by farmers to adhere to clean air laws. "This is not a backroom deal," said John Thorne, a lobbyist for Capitolink, a consulting firm representing the National Pork Producers Council and other industry groups. "You can't negotiate technical, scientific issues in a fish bowl," Thorne said. "The public will have ample opportunity to comment later on." He said that it makes sense to extend some protection to farmers who volunteer to participate and pay for the study of emissions so that the information gained can't be used against them for past infractions. The Clean Air Act had not been applied to factory farms until about four years ago, when the EPA began using estimates of emissions to seek large fines against some of the largest producers. The scientific study proposed by the industry, Thorne said, would resolve the question of whether farms are violating the clean air rules. Critics, however, say the proposal is the latest in a string of efforts by the Bush administration to roll back environmental regulations opposed by industry and pro-business groups. "They're taking giant steps backward," said Joe Rudeck, a senior scientist in Raleigh, N.C., with Environmental Defense, a national environmental group. "If the EPA wants to monitor farms, they should, but the research shouldn't be tied to enforcement concerns." Rudeck also criticized the fact that environmental groups were not invited to participate in the negotiations. The association that represents state and local environmental-enforcement officials was invited to participate but withdrew from the talks in protest and now opposes the deal. Waste in the large lagoons of feces and urine common on industrial hog farms evaporates in hot weather, as does the waste pumped and sprayed onto fields as fertilizer. Environmental groups said that the gases released, including ammonia and nitrogen, rain back down and pollute rivers and ground water. North Carolina's hog population has grown faster than that of any state, swelling from 2.6 million in 1987 to an estimated 10 million hogs today, nearly a 285 percent increase. The hogs are estimated to produce 19 million tons of sewage each year — more than the human population of Charlotte, N.C., would produce in 58 years. Don Reuter, a spokesman for the North Carolina Department of Environment and Natural Resources, said that the agency was not privy to the negotiations between the EPA and the hog industry. He said if the reports are true, the state would likely oppose the deal. "In general, we would oppose any action that would restrict our ability to enforce matters of concern to the state," Reuter said.