Authorities are working to clean up 300,000 gallons of manure that spilled into Silver Creek on the Oneida Reservation Monday. According to a Department of Natural Resources news release, the spill occurred when a valve on a holding structure failed at 1 p.m. Monday at the Phil Robertson farm on Brown County E in Oneida. An estimated 300,000 gallons of manure were released into a grassy waterway and Silver Creek, a tributary of Duck Creek. The farm is not a concentrated animal feeding operation (CAFO), the release said. The spill has killed a number of fish, including minnows and bluegills as far as 3 miles north. It also reached Duck Creek. People are advised to stay away from the affected waterways. Crews from the Oneida Reservation, Outagamie County and the DNR are assisting with cleanup. Oneida Nation staff and the DNR are monitoring water quality.