On September 24, arguments began in Oklahoma v. Tyson, a 2005 lawsuit filed by the Oklahoma Attorney General against poultry companies operating in the Illinois River Basin. The lawsuit alleges violations of federal environmental laws, state and federal public nuisance law, and state statutes regulating pollution of waterways. Oklahoma's legal strategy is unique: the state is bringing the suit under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, more commonly known as the Superfund Law) to target the nonpoint source pollution of water. Success for Oklahoma in this case would signal a serious development in protecting water from nonpoint source pollution.

The defendant companies – 11 poultry producers including Tyson Foods, Cargill Turkey , Peterson Farms, Simmons Foods, and others – contract with large-scale poultry farmers across the basin, which covers 1 million acres between Oklahoma and Arkansas. They provide the farmers with the chicks, feed, and other support while the farmers themselves actually own, operate, and manage the poultry operations. An estimated 1,850 poultry farms operate in the basin, generating nearly 345,000 tons of poultry "litter" each year. The farmers either apply it as fertilizer to their own lands or sell it to other farmers to do the same. Poultry litter includes fecal waste and poultry bedding materials, and contains such bacterial pollutants as E. coli, salmonella, and Campylobacter, as well as such nutrient pollutants as phosphorus, nitrogen, zinc, and copper. 

In opening arguments, Oklahoma Attorney General Drew Edmondson asserted that this poultry litter has caused the fecal bacterial contamination of waterways in the Illinois River Basin. Heavy rainfalls wash the poultry litter into waterways, rendering the water unfit for consumption and human recreation, and causing unreasonable interference with the public's use and enjoyment of the waterways, he said. Oklahoma's lawsuit seeks a number of comprehensive remedies, including a permanent end to the practice of applying litter to the land around the poultry farms, and finding the companies liable for all past and future costs associated with restoring the health of the waterways.  

If the state wins the case, the implications could be hugely significant, not just for the Illinois River Basin but for other waterways polluted by animal waste. For example, poultry operations in the Chesapeake Bay dwarf those in the Illinois River Basin. In 2008 alone, the region produced 1.5 billion pounds of manure. Applied to land, the manure and other components of poultry litter run off into the Chesapeake Bay.  The manure is responsible for 19 percent of the total nitrogen and 26 percent of the total phosphorous in the Bay, and the excess nutrients cause dead zones and other severe ecosystem damage. Perdue and other companies continue to escape liability because they disclaim ownership of the manure, despite owning and providing the chicks, feed, and other supplies to the farmers who grow the chickens under contract with them, and because of the lack of regulation for water pollution from runoff under the Clean Water Act. In a telling interview for PBS's Poisoned Waters documentary, Jim Perdue disingenuously disclaimed ownership of the manure, saying: