In a stunning move that relieved and surprised local activists, the region’s air pollution watchdog plans to seek a ban on a highly toxic acid used at oil refineries in Torrance and Wilmington, the Daily Breeze has learned.

Susan Nakamura, acting assistant deputy executive officer with the South Coast Air Quality Management District [AQMD], said a series of safety “mishaps” that have plagued the PBF Energy-owned refinery in Torrance, coupled with new information about community risks associated with the use of supposedly safer modified hydrofluoric acid, prompted what’s dubbed Rule 1410.

A massive explosion on Feb. 18, 2015, that almost caused a “catastrophic” release of thousands of pounds of the potentially lethal acid literally shook the community and focused renewed attention on the dangers of HF.

The acid can create a ground-hugging toxic cloud that could kill or injure thousands.

Since the blast, the refinery has experienced a string of safety issues.

Those include more flaring incidents than usual that have sent thick plumes of black smoke billowing across the city, several plant shutdowns caused by electrical grid issues and at least one HF leak.

In November, a fire occurred in or near the alkylation unit, where thousands of gallons of acid is stored, although city officials downplayed the severity of the incident.

Safety Mishaps Cited

“Based on different mishaps at the Torrance Refinery, our agency has decided it wants to look at a rule phasing out hydrofluoric acid,” Nakamura said. “You put it all together and there’s overall concern about the safety of the refinery.”

Nakamura noted that the proposal was based, in part, on technical analyses performed by a six-member scientific advisory panel formed under the auspices of the Torrance Refinery Action Alliance.

That grass-roots group, organized in the wake of the 2015 explosion, has lobbied for an HF ban.

Simultaneously, the group, led by its president, retired scientist Sally Hayati, began investigating claims that an additive to the hydrofluoric acid designed to inhibit cloud formation conferred an additional safety margin over unmodified acid.

An analysis found that, contrary to public claims of a supposedly independent study city officials conducted in the 1990s in response to HF concerns in the community, the level of additive in use was so low that in practice it would do little to prevent formation of a dangerous cloud of toxic vapor.

Modified Acid a Fraud?

“They’re basically admitting that modified HF isn’t exactly what it was pretending to be, without saying it in so many words,” Hayati said. “MHF is, in fact, a fraud and the safety claims made for modified hydrofluoric acid by 1990 are fraudulent. They’re meant to deceive the public into continuing to accept the existence of MHF at the refinery.”

Torrance officials have never publicly acknowledged that the city quietly signed off on a court order allowing a reduction in additive from 30 percent to 10 percent — and an increased risk to the community — because in higher concentrations it interfered with gasoline production.

The refinery, which employs hundreds of workers, has long been an important source of tax revenue for the city.

Safety Systems Flawed?

Even worse, vaunted safety systems in place at the refinery are based on the higher concentrations of additive so the “claims on these barriers are not technically sound,” said Jim Eninger, a retired TRW engineer who worked with hydrofluoric acid during his career and is a member of the TRAA advisory panel.

“Modified hydrofluoric acid is very effective as a public relations element,” he said. “It’s very ineffective as a safety measure. What started out as a silver bullet ended up as a hail Mary pass that didn’t work.”

Nakamura said the work of Hayati and the TRAA has raised sufficient questions about the safety of MHF to warrant a closer look by the agency at safety claims surrounding it.

That makes it at least the second government agency to do so.

The Environmental Protection Agency announced in December 2015 that it had opened an investigation into whether the refinery’s risk management plan understates the number of deaths and injuries that could occur under a worst-case-disaster scenario.

The EPA said officials began looking into the issue after TRAA alerted them to apparent unexplained discrepancies in the risk management plans for the two refineries.

The two South Bay refineries are the only ones in the state that use HF.

PBF officials were not immediately available to comment Tuesday. Officials with the Valero Wilmington Refinery did not respond to a message.

But Torrance Mayor Pat Furey — who has repeatedly said the city must place its trust in the hands of regulatory agencies when it comes to refinery safety — applauded the responsiveness of the AQMD.

“It appears the AQMD recognizes the concerns of many of our residents and are addressing those concerns,” he said via email. “For that, I am pleased.”

The proposed rule is among several the agency is contemplating that were quietly published on its website last month as required by state law.

Other proposed rules included tighter control of emissions from refinery flares and new requirements for fence-line air monitoring near refineries.

The agency said in October — after a series of flaring incidents at the Torrance refinery — it intended to pursue the latter two rules.

But the proposed HF ban is a surprise because PBF Energy has pushed back against using a different process to manufacture high-octane fuel, questioning the commercial viability of possible alternatives.

An AQMD study last year said switching to an alternative technology in Torrance would cost more than $100 million, a figure PBF challenged as too low.

Multiple state and federal agencies are investigating safety issues at the refinery.

ExxonMobil, the refinery’s previous owner until PBF acquired it last year, was fined hundreds of thousands of dollars for safety violations caused by what regulators charged was a deliberate failure to make repairs despite knowing that could cause a life-threatening explosion.

The agency is expected to take most of the year to formulate any HF ban. It could take a couple of years after that to phase out its use at local refineries, but TRAA hopes that occurs by Jan. 1, 2020.

“We feel they should accelerate the (rule-making) process because of all the deception involved,” Hayati said. “For years, the South Bay thought we had eliminated the danger of hydrofluoric acid when all along HF has always been there. We nearly paid for that on Feb. 18, 2015, with our lives.”