An oil spill discovered in the Kennebec River in Clinton in late April came from the Skowhegan paper mill up the river, the U.S. Coast Guard found.
The paper mill’s management initially denied that the oil belonged to it, according to emails obtained by the Bangor Daily News between the mill’s management and regulators. But a mill spokesperson confirmed Wednesday that it is aware the oil has the same “chemical signature” as the fuel oil used at its Somerset Mill and has cooperated fully with regulators.
“No one wants oil in the Kennebec, including us,” Sappi spokesperson April Jones said.
The spill occurred on the weekend of April 26, when the Maine Department of Environmental Protection notified federal officials about it, as first reported by the BDN. The almost 2-mile spill involved an industrial-grade lubricant called No. 6 oil and was originally estimated at about 2,000 gallons, although measuring the total spill volume has been challenging, according to DEP spokesperson David Madore. The investigation is ongoing.
“The DEP is currently collaborating with the Environmental Protection Agency to assess potential enforcement actions related to the discharge into the river,” Madore said.
Clinton resident Cathy Sioch reported the spill to the DEP after she went to work in her garden, which abuts the river, she said in an interview at the time. 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.
Even though Sappi officials continued to deny any link to their mill directly after the spill, a forensic analysis by the U.S. Coast Guard matched the No. 6 oil at the Clinton spill to oil at the mill.
“All oil has its own fingerprint, so to speak, of where it’s been, how it’s made, where it comes from,” said Lt. Cmdr. Blake Maurer of the Coast Guard.
There were two oil leaks on the Sappi campus within a couple weeks of the oil being discovered in Clinton. The company reported an incident on April 16 that involved 2,000 gallons of oil spilled from a tank into its retention pond. On April 22 it reported another spill on its campus caused by spraying No. 6 oil from the cleanup of a wood chip pile. The third report came from Sioch on April 26.
In an April 23 email to the DEP, Sappi’s senior process engineer, Ross Nason, denied that the Clinton spill was related to the earlier spills at the mill.
“We have found no evidence of a discharge of oil to a Maine waterway,” he wrote to the DEP.
But by early May the Coast Guard had identified Sappi as the source of the Kennebec River spill and notified the DEP. Agencies have not said how many gallons of oil were spilled.
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.
Lori Valigra reports on the environment for the BDN’s Maine Focus investigative team. Email her at lvaligra@bangordailynews.com. Support for this reporting is provided by the Unity Foundation, a fund at the Maine Community Foundation and donations by BDN readers.