As farmers and ag retailers prepare for another growing season by applying the proper crop nutrients to their fields, they will see the issue of fertilizer runoff in the Midwest heating up thanks to a new lawsuit.

A lawsuit has been filed against the Environmental Protection Agency for not doing enough to keep fertilizer pollution out of waterways. The Iowa Environmental Council has joined other groups in suing the EPA over its inability to set numerical limits on nitrogen and phosphorus in waterways under the Clean Water Act.

The current lawsuit stems from EPA’s rejection of a petition filed by the groups in 2008. The groups say the rejection of their petition was a violation of federal administrative rules and was arbitrary, the Des Moines Register reported.

“This is a massive, multi-state problem, but the EPA has not accepted its responsibility for leadership on this issue, and state responses—including in Iowa—have languished as a result,” Marian Riggs Gelb, executive director of the Iowa Environmental Council, told the Des Moines Register. “In addition to the Gulf dead zone, excessive amounts of nitrogen and phosphorus from farm runoff and sewage treatment plants wreak havoc here in Iowa as well, threatening drinking water, recreation in our lakes and rivers, and aquatic life here and downstream.”

The issue stems from a later issue in 1998 when EPA called on states to adopt specific limits on nitrogen and phosphorus pollution. EPA had threatened to enact its own limits if states had not complied by 2003. According to the Iowa Environmental Council, one of the groups suing the EPA today, all Mississippi River states failed to enact their own limits. EPA later set flexible deadlines for states if they showed they were working to reduce pollution.

A factor that helped kick off the lawsuit was Iowa stopping a couple of its efforts to reduce the pollution. In addition, EPA changed its calendar deadlines for setting nitrogen and phosphorus limits in streams.

Groups listed as plaintiffs include Environmental Law & Policy Center, Missouri Coalition for the Environment, Sierra Club, Waterkeeper Alliance, Tennessee Clean Water Network, Minnesota Center for Environmental Advocacy, Kentucky Waterways Alliance, Prairie Rivers Network and Gulf Restoration Network.