Nearly 8,000 gallons of ‘slop oil’ spilled at onshore Hilcorp facility near Cook Inlet

An aerial view of an oil production facilities shows a series of buildings near the Cook Inlet waters
An aerial view of Hilcorp’s Trading Bay production facility, where the oil spill occurred. (Screenshot of report by the Alaska Department of Environmental Conservation)

Oil and gas company Hilcorp is cleaning up an oil spill on the western side of the Cook Inlet, about 20 miles northwest of Kenai.

That’s according to a report Wednesday from the Alaska Department of Environmental Conservation.

The state says nearly 8,000 gallons of “slop oil” leaked out of an underground line at Hilcorp’s onshore Trading Bay production facility. 

Slop oil is about 80 percent crude and 20 percent water, said the state’s report. It needs to go through additional treatment before it’s sold.

The oil mix was being moved between tanks when it leaked out of the underground line. It pooled in and on top of the soil, but did not go into Cook Inlet waters, according to Crystal Smith, central region manager for the environmental conservation department.

An operator first noticed the leak Tuesday afternoon. 

In a statement Wednesday, Hilcorp spokesman Luke Miller said the underground line was “immediately isolated” and the spilled oil remained within a tank containment wall.

Nine Hilcorp employees on site recovered about 630 gallons of the spilled oil Tuesday, according to the state’s report. More workers were headed to the area to help with clean-up. Also, Hilcorp said, environmental specialists were traveling to the scene.

By Wednesday, the state said it had not received any reports of impacts to wildlife. The Hilcorp facility is located near the Trading Bay State Game Refuge and the Redoubt Bay Critical Habitat Area.

The cause of the leak remains under investigation, the state says. 

RELATED: State regulatory commission gives final approval for BP-Hilcorp deal

Reach reporter Tegan Hanlon at or 907-550-8447.

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