By THE ALASKA STORY
Aug. 24, 2026 – A pilot flying over Cook Inlet on Monday afternoon spotted what appeared to be a five-mile-long oil sheen near an inactive offshore platform, triggering a multi-agency response as officials work to identify the source.
The sheen was reported at approximately 2 pm Monday, Aug. 24, about five miles south of Tyonek on the west side of Cook Inlet, according to media reports.
The pilot reportedly flies the route regularly and notified the Alaska Department of Environmental Conservation after seeing the unusual discoloration on the water.
The US Coast Guard, Alaska Response Corp. and the Alaska Department of Fish and Game were among the organizations said to be involved Monday evening.
The source of the sheen had not been determined. Officials were investigating whether it could have come from an offshore installation, an underwater pipeline, a vessel, or another source.
The reported sheen was observed near the inactive Spark platform, which has not produced oil or gas for decades. The unmanned structure, built originally by Marathon Oil, is maintained in what the industry calls “lighthouse mode,” meaning it remains standing but is not used for active production.
