While the headlines and costs of a four-month natural gas storage well leak that ended last month concentrated on nearly 10,000 residents who decided to leave their homes in the upscale Porter Ranch section of the Los Angeles San Fernando Valley, the majority of residents stayed put in the area of the Aliso Canyon underground gas storage field.

Less than a quarter of the Porter Ranch homes were vacated, and Southern California Gas Co. (SoCalGas) underwrote the relocations as well as weatherization and air filtration systems for the majority the families that chose to stay. Cost estimates now are placed at nearly $350 million by the utility as of the end of last month.

Even after the permanent closure and sealing of the leaking well (see Daily GPI, Feb. 18), controversy and criticism are being aimed at Sempra Energy and SoCalGas. Dislodged residents that SoCalGas has been subsidizing want more time and assurances before returning home, and they have won favorable court rulings to get the utility’s extended support.

On Tuesday, SoCalGas CEO Dennis Arriola said the nation’s largest gas-only utility was working to continue to support the surrounding community near the 3,600-acre storage field.

“We are working to re-establish processes to support eligible residents who wish to remain in the temporary relocation program, [but] because the program had been demobilized last week following permanent sealing of the well, this is a challenging task,” said a SoCalGas spokesperson.

According to the latest statistics from SoCalGas, there are about 42,000 households in five affected zip codes near the leak, and 15-20% chose to temporarily relocate. SoCalGas provided air scrubbers to more than 8,200 homes.

The utility also delivered more than 19,000 plug-in air filtration units to about 7,500 homes, and weatherized 8,200 of the homes. “We also offered mileage reimbursement for residents who had to drive extra miles to go to work or take children to school,” said a SoCalGas spokesperson, adding that pet relocation was provided, even when families stayed put.

For relocations, SoCalGas as of Tuesday had mailed more than 15,000 expense reimbursement checks; 3,700 of them last week, the vast majority for meals and lodging.

“The total costs incurred to remediate and stop the leak and to mitigate environmental and local community impacts will be significant and to the extent not covered by insurance, or if there were to be significant delays in receiving insurance recoveries, such costs could have a material adverse effect on SoCalGas’ and Sempra’s cash flows, financial condition and results of operation,” SoCalGas and Sempra said in recent Securities and Exchange Commission filings.

The companies said they expect that insurance will cover the bulk of the charges, including any regulatory or legal fines and penalties.