The only way to significantly reduce phosphorus levels in Oklahoma’s eastern waterways is to ban the use of chicken litter as fertilizer, a soil scientist testified last month in a nearly 20-year lawsuit against Tyson Foods and several other poultry companies. 

“To help reverse the phosphorus pollution in the waters of the (Illinois River Watershed), we have to stop making the problem worse. That means we need to stop the land application of poultry waste,” wrote Gregory Scott, a scientist with the Oklahoma Conservation Commission, in testimony presented by Oklahoma Attorney General Gentner Drummond to a federal court judge. “Nothing else will begin to clean up the problem until the land application of poultry waste stops.”

Decades ago, as industrial poultry production increased in eastern Oklahoma, chicken litter was increasingly used as fertilizer on area crop farms. Rain washed waste into nearby waterways, elevating phosphorus levels that depleted oxygen, turned water cloudy and strained the nearly 20 utility systems that rely on the Illinois River Watershed for drinking water. 

In response, then-Attorney General Drew Edmondson sued several poultry companies in 2005, including Tyson, Cargill, Inc., and Simmons Foods.

A trial was held in 2009, but it wasn’t until 2023 that U.S. District Judge Gregory Frizzell ruled for the state, agreeing that the poultry companies were to blame for the high phosphorus levels. 

Since that ruling, Frizzell said he is weighing pollution-control requirements. The poultry companies argue the case should be dismissed because too much time has passed since the 2009 trial. A hearing was held last month to hear arguments on whether the case and its evidence are still relevant. 

It was at that December hearing that Oklahoma Attorney General Drummond presented multiple witnesses, including Scott, who testified water pollution from chicken litter remains a problem. 

Last year, Drummond asked Frizzell to impose a chicken litter fertilizer limit of 65 pounds of phosphorus per acre, well below the state limit of 300.

But Scott testified a ban would be the only way to get phosphorus rates within state water standards. He also recommended using vegetative buffer strips along water edges and planting more hay in phosphorus-rich areas. 

“Haying grass grown in the IRW and physically removing it from the watershed would help deplete the amount of legacy phosphorus,” Scott wrote, referring to the Illinois River Watershed. “Removing one ton of hay grown in the phosphorus-laden soils of the IRW would remove about 15-20 pounds of phosphorus.” 

Asked about Scott’s recommendation that all land applications of poultry waste be stopped, Drummond’s office said it isn’t an action he’s specifically asking for. 

“The testimony reflects the expert opinion of the witness and not the personal opinion of Attorney General Drummond,” said Leslie Berger, a Drummond spokesperson.

Katie Mendoza, a hydraulic research specialist at Texas A&M, was also presented by Drummond as a witness. She wrote that if all chicken waste fertilizer use were stopped, phosphorus levels would decrease by an average of 5.6% annually. 

Agreeing with Scott, Mendoza said planting hay and using buffer strips could achieve an even faster rate of decline.

“In order to reduce the amount of loading that reaches the rivers and Lake Tenkiller, additional management practices are needed beyond the cessation of poultry waste land application,” Mendoza wrote, referring to the large lake in the Illinois River Watershed. 

During last month’s hearing, poultry company attorneys and witnesses argued that the amount of chicken litter transported out of state has significantly increased. However, at least one of their scientific witnesses acknowledged that the waterways remained impaired based on state standards. 

Governor, ag secretary urge judge to drop case

While Drummond, a Republican, has continued representing the state’s case, other state officials, including the governor, have criticized the lawsuit and warned that court-imposed restrictions could hurt farmers. 

In September, Oklahoma Secretary of Agriculture Blayne Arthur wrote a letter urging Frizzell not to require additional pollution standards. 

“Respectfully, judicial adjustment of standards and requirements applicable to the poultry industry may circumvent the lawmaking process, which is best left to elected legislators and officials in the executive branch,” Arthur wrote in a letter she filed in the case. 

Last year, Oklahoma lawmakers passed a bill shielding poultry companies from future lawsuits over pollution caused by chicken litter waste. 

Gov. Kevin Stitt, a Republican, signed the bill into law, saying he wanted to stop “frivolous lawsuits” like the current one against Tyson and other poultry companies.