State and federal officials are investigating the source of a small weekend oil spill in the Kennebec River in Clinton that observers said covered up to a mile of shoreline.
The Maine Department of Environmental Protection notified federal officials Sunday about the spill, according to a report obtained by the Bangor Daily News. The spill involved an industrial-grade lubricant called No. 6 oil, sources said. State officials are working with their federal counterparts to determine the source and size of the spill, a DEP spokesperson said Thursday.
The spill occurred downstream of Sappi’s Somerset Mill in Skowhegan. A spokesperson said the mill is cooperating with federal and state officials as they investigate the source.
“Maine DEP has indicated it is evaluating multiple potential sources in the broader area, and we support a thorough, fact-based process,” Sappi spokesperson April Jones said. “The Kennebec River matters deeply to this community and to us.”
Recent oil spills in Maine rivers include 75 gallons of heating oil in Kenduskeag Stream in Bangor in November 2025, heating oil in the Presumpscot River in Westbrook in November 2024 and a 1,680-gallon biodiesel spill in the Androscoggin River and Jepson Creek in Lewiston in February 2024.
Clinton resident Cathy Sioch reported the spill to the DEP after she went to work on her garden, which abuts the river, she said in an interview. The water looked as if black candle wax had dripped all over the surface. When she touched the substance, it felt like used car oil, she said. The oil dripped off branches carried by the spill and pooled between rocks, she said.
“The water level was down, which is why I noticed it,” she said of the small beach on her property. “We got the worst of it.”
Part of the area is marshy, and a pair of Canadian geese have nested there every year for the past seven years, she said. Sioch noticed that the male goose had some oil on the tips of his feathers but appeared to be OK. First responders from the DEP, the Coast Guard, the Maine Department of Inland Fisheries and Wildlife, and the Maine Warden Service cleaned up the scene quickly, Sioch said.
“It’s concerning considering there’s so much wildlife here, including otters,” she said.