ExxonMobil Corp., hounded by regulatory investigations into its safety record since a February explosion tore through the company’s Torrance refinery, confirmed Wednesday it has sold the crippled plant for $537.5 million to independent refiner PBF Energy.

“The sale results from a strategic assessment of the site and how it fits with our refining portfolio,” Jerry Wascom, president of ExxonMobil Refining & Supply Co., said in a statement.“ExxonMobil regularly adjusts its portfolio through investment, restructuring or divestment consistent with overall global and regional business strategies.”

The announcement Wednesday afternoon comes a year to the day after industry sources confirmed to the Daily Breeze that the refinery was on the block. That would-be buyer turned out to be New Jersey-based PBF, which will become the fifth largest independent refiner in the United States once the sale of the Torrance refinery closes.

ExxonMobil’s 700 employees, including about 600 at the 750-acre refinery itself, were informed of the sale shortly after 1 p.m. All were offered jobs with PBF.

Another 700 contract workers also are expected to continue working at the refinery.

“Along with the refinery, we’ll be acquiring the pipelines, the terminal that supports the refinery operations,” said Jeffrey Dill, president of PBF’s newly formed subsidiary, PBF Energy Western Region LLC. “We expect the acquisition to close in the first half of next year.”

With acquisition of the 155,000-barrel-a-day refinery, PBF will increase its refining capacity to 900,000 barrels a day. The company owns refineries in Ohio, New Jersey and Delaware, and is buying another in Louisiana.

The Torrance refinery currently is operating at less than 20 percent of capacity, but the sale is contingent upon the plant being completely repaired before it closes escrow.

Among the assets PBF acquires are a 171-mile pipeline that delivers oil from the Bakersfield area to the refinery as well as terminals in Anaheim and Vernon, which also has a lubricants distribution center. Pipelines to the ports of Long Beach and Los Angeles and another that delivers jet fuel to Los Angeles International Airport also were included in the deal.

The refinery has crude and product storage facilities with a capacity of about 8.6 million barrels.

“Southern California is a very attractive market and we are excited to become a supplier in the region,” said PBF Executive Chairman Tom O’Malley. “PBF’s management team has extensive experience operating in California and we are entering at a very attractive purchase price for the Torrance refinery.”

It’s unclear whether ExxonMobil is still planning to fire up an outdated piece of pollution control equipment to increase gasoline production while it rebuilds the one installed just a few years ago but ripped apart in the Feb. 18 blast.

“As far as I know, they still have the option of pursuing that interim measure with the AQMD,” Dill said.

Some critics have suggested the sale is an attempt by ExxonMobil to avoid accountability for the explosion. Dill said that won’t happen.

“They will still be responsible for the matters that relate to that incident,” he said. “We know we have to earn the right to be in the communities that host us and we look forward to doing that in Torrance.

“Our focus — and it’s really our sole focus — is running the refinery safely and reliably,” he added. “We’re looking forward to giving the refinery a fresh start.”

Still, the company has no plans to stop using hydrofluoric acid in the refining process. Critics, including a recently formed grass-roots group, contend the toxic and potentially deadly vapor that can form after an accidental release should no longer be used at the refinery.

“That’s an integral part of the Torrance refinery,” Dill said. “We try to be as transparent as we can.”

In a CBS News broadcast Wednesday night, the recently appointed head of the U.S. Chemical Board, Vanessa Sutherland, said the ExxonMobil explosion could have been “catastrophic.”

The force of the blast sent an 80,000-pound piece of equipment flying more than 100 feet. It landed just yards from a vessel containing HF; if it had ruptured, thousands of injuries or deaths could have occurred, CBS said.

“If I were in the community, I absolutely would be concerned,” Sutherland said.

Nonprofit group Consumer Watchdog estimates the gasoline price spike after the explosion cost Californians at least $6 million more than they would have paid otherwise.

It issued a statement Wednesday urging federal and state investigators to ensure evidence from the explosion is not destroyed during the transfer of ownership.

In a recent letter written to Gov. Jerry Brown and other top government officials, Consumer Watchdog alleged ExxonMobil had covered up key evidence and was preventing a witness from talking to state investigators looking into the cause of the explosion. Cal/OSHA has issued 19 health and safety violations against ExxonMobil, contending it deliberately failed to fix a piece of equipment that led to the explosion.

“If Exxon can’t keep gas flowing to the state and keep our neighborhoods safe, it shouldn’t be able to avoid accountability for the explosion that took place in February,” said Jamie Court, president of Consumer Watchdog.

South Bay Rep. Ted Lieu has previously said the Justice Department may have to step in to compel ExxonMobil to comply with subpoenas for explosion-related information sought by U.S. Chemical Safety Board investigators.

“Until the refinery sale is finalized in 2016, I will continue to hold ExxonMobil accountable for the ongoing refinery safety and pollution concerns and do all that I can to ensure their cooperation with state and federal regulators,” he said.

Consumer Watchdog welcomed the new entrant into the California market, believing it could benefit consumers through increased competition. Just two companies — Chevron and Tesoro — control 54 percent of the state’s refining capacity.

Torrance Mayor Pat Furey had a similar view.

“While one company may be moving on, we are gaining a new entrant to the California market,” he said in a statement. “I’m encouraged to see a new company embrace a tremendous opportunity to invest in business and manufacturing in our great state.”

The refinery began operating in 1929.

Mobil operated the plant for almost three decades before it merged with Exxon in 1999. It is the only refinery in California owned by ExxonMobil.

The union representing workers at the plant also welcomed the ownership change.

“We do look forward to having a positive relationship with PBF,” said David W. Campbell, secretary-treasurer with United Steelworkers Local 675 in Carson. “We have dealt with them in the past and we have found them to be very pragmatic business people.”

The deal was announced after stock markets had closed for the day.

ExxonMobil stock rose $1.29 Wednesday to finish the day at $74.25. PBF stock was up $1.28 to $29.50 in after-hours trading.“