Hilcorp estimates leak at 3 gallons of crude; unified command stands down

An underwater pipeline that sprung a leak in Alaska's Cook Inlet, an area known for diverse marine life, probably dumped less than three gallons of crude oil into the ocean, the pipeline's owner said Monday.

The spill between two production platforms owned by Hilcorp Alaska LLC was spotted Saturday. Cook Inlet stretches 180 miles from the Gulf of Alaska to Anchorage and is home to an endangered population of beluga whales.

Hilcorp by Sunday had removed all oil from the 8-inch diameter pipeline.

Cook Inlet is also habitat for humpback whales, the western population of Steller sea lions and northern sea otters. Harbor seals, killer whales and porpoise use the inlet.

The Kenai Peninsula makes up the eastern side of the inlet and draws thousands of anglers every summer seeking halibut in the inlet or salmon in ocean water and streams.

The spill volume was estimated from the size of sheens that were seen, said company spokeswoman Lori Nelson in an emailed response to questions. The sheens dissipated, Nelson said.

In three flyovers Sunday and a final one Monday morning, no additional sheens were spotted from the air.

Hilcorp, the Coast Guard and state environmental authorities over the weekend formed a unified command in response to the spill that was suspended Monday, said Candice Bressler, spokeswoman for the Alaska Department of Environmental Conservation.

The leak's cause was unknown.

The leak is the second in Cook Inlet this year for Hilcorp Alaska, a subsidiary of Houston-based Hilcorp.

In an unrelated incident, processed natural gas continues to spew into the inlet from an underwater pipeline that supplies four other production platforms.

The platforms burn natural gas for power. That leak was discovered in February and company officials estimate it has been leaking since mid-December.

Hilcorp says the gas leak will be repaired after floating ice no longer poses a threat to divers who would perform repairs.

The oil leak was discovered Saturday, April 1, when workers on the Anna Platform "felt an impact," according to the DEC. They spotted an oil sheen and bubbling in the water near one of the platform's legs.

The suspected leaking line connects Anna Platform with Bruce Platform in 75 feet of water.

The 1.6-mile line has a capacity of 19,362 gallons and was full. Hilcorp Alaska shut down the platform and lowered pressure in the pipeline to zero.

Overflights spotted six sheens. The largest was 10-by-12 feet.

Bressler said Hilcorp used a polyurethane "pig," a device inserted into the pipe, to push remaining crude oil toward the Bruce Platform. It was processed and moved to a tank farm.

Hilcorp has detected no harm to wildlife, Nelson said.

Story from Sunday, April 2

(AP) — Alaska officials say an oil leak has been discovered in the Cook Inlet and a major oil and gas producer has shut down two of its platforms there.

The Alaska Department of Environmental Conservation says Hilcorp Alaska LLC workers first noticed an oil sheen and bubbling from underwater near the company's Anna platform at about noon Saturday.

The spill is on the west side of Cook Inlet, to the southwest of Anchorage.

Officials say leak is from a underwater pipeline that is carrying more than 19,000 gallons of crude oil. It's not clear how much oil is spilling into the inlet.

Hilcorp lowered the pressure in the line and has hired a diving contractor to investigate the leak.

"It has been less than a week since Hilcorp agreed to temporarily shut down oil and gas production as part of its response to a leaking gas supply line," Gov. Bill Walker said in a Sunday statement from his office. "Now, Hilcorp has reported a seperate leaking oil line — which is significantly more harmful than natural gas. I am deeply concerned about the potential impact to the environment. The oil line has been shut in. Our (DEC) Spill Prevention and Response team has immediately responded, and is keeping me apprised of developments."

Natural gas has been leaking from another Hilcorp pipeline in the Cook Inlet since mid-December.

Updated: 
04/03/2017 - 4:02pm

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