The U.S. government will impose new federal rules to reduce the risk of leaks at natural gas storage facilities in the wake of 2015's massive methane leak at California's Aliso Canyon, a task force said on Oct. 18.

Operators should phase out "single point of failure" designs, which hindered the ability to swiftly control and repair the leak at Aliso Canyon, the task force said, giving a total of 44 recommendations.

SoCalGas, owned by California's Sempra Energy, shut Aliso Canyon in October 2015 due to a massive methane leak that was not plugged until February. Aliso Canyon is the biggest of its four storage fields and supplies gas to homes and businesses in Southern California, including power plants and refineries. The months-long gas leak forced thousands of Los Angeles residents from their homes and was the largest known accidental methane release in U.S. history.

To avoid future pipe failures, the task force recommended storage facilities upgrade their wells to include a two-pipe design with a casing pipe cemented to the rock wall surrounding the well with another pipe inside the casing pipe. The gas would move through the middle pipe, so if there was a leak, it would be contained within the casing pipe.

The task force recommended using a phased approach, which would likely take years to implement, to get storage operators to upgrade wells to include the two-pipe design.

The U.S. Department of Transportation expects to publish new rules for the industry by the end of the year, said Marie-Therese Dominguez, administrator of the department's Pipeline and Hazardous Materials Safety Administration. She co-chaired the task force along with Franklin Orr, under-secretary for science and energy at the U.S. Department of Energy.

Dominguez could not estimate the cost of the new rules, but said that would be part of the review.

The task force said there were 12 storage facilities that potentially could affect 2 gigawatts or more of power generation capacity, including Aliso Canyon. Five of the facilities are located in Mississippi; three are in Louisiana; two are in California; one is in Michigan and one is in New York.

For these and other facilities, the task force called for better coordination between electric grid operators, storage providers and others.