Hilcorp has reported another spill this week.
The Alaska Department of Environmental Conservation confirmed the spill happened Monday on the Steelhead platform the company operates in the Trading Bay oil field in Cook Inlet.
DEC spokesperson Candice Bressler said 200 gallons of an oil-based drilling mud was released from the platform, of which, 2 gallons ended up in Cook Inlet.
The cause of the spill is still under investigation, and Bressler says DEC is working the company to review safety protocols.
Hilcorp owns 15 of the 17 drilling platforms in the Inlet.
Routine tests were performed on Steelhead in June to make sure blowout valves were working properly.
A natural gas pipeline running from the platform was the source of a subsea gas leak earlier this year.
