Responders to Cook Inlet oil sheen shift to ‘monitoring’ status

U.S. Coast Guard personnel conduct aerial survey of the North Trading Bay sheen location and the inactive Spark platform on Wednesday, Aug. 26, 2026 in Cook Inlet, Alaska.
U.S. Coast Guard personnel conduct aerial survey of the North Trading Bay sheen location and the inactive Spark platform on Wednesday, Aug. 26, 2026 in Cook Inlet, Alaska. (Chief Petty Officer Christopher/U.S. Coast Guard)

Agencies responding to an oily sheen reported in Cook Inlet earlier this week are switching from response to monitoring mode. A joint command announced the transition Thursday after going several days without seeing any sheen in the area.

The command includes the Alaska Department of Environmental Conservation, the U.S. Coast Guard and Hilcorp Alaska, which owns a decommissioned oil platform near where the sheen was seen.

On Tuesday, the state said Hilcorp would inspect and test pipes and hoses in the area, and repressurize shut-in lines – a common practice in oil spill responses. The state said the oil response ship would remain in the area while that testing happened.

In the Thursday update, the command says crews conducted grid searches, flyovers and surface monitors and did not see any oil. Hilcorp also investigated its Spark Platform, which was decommissioned in the 1990s, and did not find a potential source of the sheen.

The command says it will continue investigating the source and nature of the initial sheen reported Monday, with flyovers continuing as appropriate.

The state says a pilot flying over the area Monday reported seeing a mileslong sheen in north Trading Bay, about 30 miles northwest of Kenai. The U.S. Coast Guard responded along with Hilcorp and an oil response ship deployed by the Alaska Response Corporation.

KDLL - Kenai

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