Hilcorp Alaska must replace its Cook Inlet pipeline, according to a mandate the U.S. Pipeline and Hazardous Materials Safety Administration issued Tuesday. The company reported a natural gas leak off the coast of Nikiski on April 1.

State and federal agencies are concerned about the leak’s damage to marine life in the Cook Inlet, which is deemed an environmentally sensitive area due to the presence of endangered animals including beluga whales, sea lions, humpback whales, harbor seals, killer whales, sea otters, and porpoises.

The Anchorage Daily News reported the size of the leak to be between 75,000 and 150,000 cubic feet a day, which could fuel close to 400 homes a day during the winter.

The PMSA also stated the life and property risk will likely increase as the ice on the inlet dissipates.

According to the Alaska Department of Environment Conservation, Hilcorp began reducing pressure on the pipeline after the April 1 leak. The PMSA report states it ordered the oil company to replace the pipe within a year after officials continued to report sheen and bubbles on the water’s surface.

The April 1 leak marks the fifth from this pipeline since June 2014, according to the PMSA. Rocks under the surface of the inlet caused four spills, and one in 2019 was caused by corrosion and weld discontinuity.

Upon analyzing risk factors to the pipeline and surrounding environment, the PMSA states the “amended order mandating immediate corrective action is issued expeditiously without prior notice and opportunity for a hearing.”

Reach reporter Camille Botello at camille.botello@soundpublishing.com.