Environmentalists gave notice Tuesday of their intent to sue a South Georgia pulp mill they allege has fouled the Altamaha River.

A spokeswoman for the Jesup-based Rayonier Performance Fibers plant did not immediately respond to a request for comment.

Deborah Sheppard, executive director of the Altamaha Riverkeeper group which took the action, said efforts over the years to collaborate with the company have not worked.

“They have simply failed to do what is right for the river,” Sheppard said.

The federal Clean Water Act requires a 60-day notice before the group can formally file a lawsuit. It amounts to a cooling off period, and is meant to give the company time to address the group’s allegations. Sheppard’s group says the company, which is legally allowed to pump treated wastewater into the river, has polluted the river with brown, smelly discharge.

Rayonier, headquartered in Jacksonville, Fla., manages more than 690,000 acres of forest in Georgia, with 850 of its 918 employees in this state working at the Jesup mill.

Its operations were cited earlier this month by the Georgia Water Coalition in the group’s annual Dirty Dozen list of some of the state’s worst polluters.

The Altamaha Riverkeeper is working with the Atlanta-based GreenLaw. The law firm, working with the Ogeechee Riverkeeper, reached what some environmentalists called a historic settlement last week on a similar lawsuit against the King America Finishing plant in East Georgia. King America agreed to pay $6.8 million to help protect the Ogeechee River, including upgrades to the factory’s wastewater discharge system.