A major leak detected almost a year ago at the Aliso Canyon natural gas storage facility has resulted in significant volatility in Southern California’s summer gas prices compared to the U.S. benchmark.

The U.S. Energy Information Administration (EIA) attributes the unstable pricing to restrictions on the use of Southern California Gas Co.’s facility following detection of a well failure and leak in late October 2015. The restrictions lowered working gas stock at Aliso to about 15 billion cubic feet (Bcf); its capacity is 86.2 Bcf.

Prices at the Southern California SoCal Citygate hub, which serves the greater Los Angeles area, have veered from a low of $2.32 per million British thermal units (MMBtu) on June 10 to a high of $3.65/MMBtu on July 22 in the June-to-August period.