An environmental group has accused a major farm cooperative of violating the Clean Water Act by discharging pollutants at a grain elevator in Washington.

The Spokane Riverkeeper nonprofit has filed a federal complaint against the Minnesota-based CHS cooperative, alleging its facility in Rockford, Wash., has released stormwater containing excessive levels of copper, zinc and turbidity into a nearby creek.

“Discharges from Rockford Elevator’s facility contribute to the ecological impacts that result from the pollution of these waters and to Spokane Riverkeeper’s and its members’ injuries resulting therefrom,” the complaint said.

Tom Ryan, global director of corporate communications for CHS, said the cooperative is aware of the complaint and is reviewing its allegations.

“We are committed to environmental stewardship and operating our facilities following all state and federal guidelines,” he said.

Aside from operating a grain and bean elevator, the Rockford facility also sells fertilizers and pesticides at the 10-acre site, which has a stormwater collection and conveyance system covered by a Clean Water Act permit, according to the lawsuit.

The facility hasn’t complied with water quality standards or properly implemented best management practices, a pollution prevention plan or corrective actions as required under the permit, the complaint said. The plaintiff also accuses the facility of repeatedly not collecting or analyzing water samples.

“Rockford Elevator’s violations were avoidable had Rockford Elevator been diligent in overseeing facility operations and maintenance,” the complaint said. “Rockford Elevator has benefited economically as a consequence of its violations and its failure to implement stormwater management improvements at the facility.”

The plaintiff alleges that the facility’s violations “are ongoing or are reasonably likely to continue to occur” and it should face a “significant penalty” to ensure the problems stop. The lawsuit seeks an order declaring that the elevator has violated its Clean Water Act permit and an injunction against future violations.

The complaint also seeks an order requiring the facility to implement an adequate stormwater pollution prevention plan and to turn over relevant regulatory documents to Spokane Riverkeeper for three years.

The lawsuit argues the facility should be subjected to civil penalties of $37,500 to $56,460 per day of violation, depending on when they occurred, and ordered to pay the plaintiff’s litigation expenses.