The EPA has opened an investigation into whether ExxonMobil understated the possible effects of a worst-case industrial disaster at its Torrance refinery, becoming the latest government agency to probe the company’s regulatory compliance in the wake of last February’s explosion.

Environmental Protection Agency spokeswoman Nahal Mogharabi confirmed that the agency is looking at ExxonMobil’s compliance with a required Risk Management Plan, although she declined to provide more details.

The Los Angeles News Group has learned that the investigation apparently was prompted by an independent analysis performed by the recently formed grass-roots Torrance Refinery Action Alliance, which includes a member of the ExxonMobil Community Advisory Panel.

The analysis shows that in the late 1990s ExxonMobil, in conjunction with Torrance Fire Department officials and City Manager LeRoy Jackson, secretly approved a reduction in the percentage of an additive intended to make extremely dangerous hydrofluoric acid [HF] safer in the event of an accidental release of the chemical.

That potentially lethal chemical, which is known to form a toxic, ground-hugging vapor cloud, was the subject of a protracted legal dispute between the city and ExxonMobil in the 1990s.

The dispute was resolved under court order when ExxonMobil pledged to modify the acid with the use of the additive that supposedly makes HF less likely to form a gas cloud that could travel long distances in the high-density urban neighborhoods surrounding the plant.

But gasoline production problems associated with the use of the additive prompted a reduction of the additive in HF from 30 percent to 10 percent.

Using just 10 percent of the additive means the potential vapor cloud is not significantly reduced in size; in other words, it isn’t much safer than unmodified HF.

Jackson last week acknowledged the reduction occurred, but disputed the 10 percent figure. He was unable to provide what he believed was the correct one.

“I’d have to go back and see what we did in 1999,” he said, although he has yet to provide any additional information.

A majority of City Council members at the time, however, including former Councilwoman Marcia Cribbs, said they were never informed of the change and would not have approved it had they known.

Former councilman and current Torrance Unified School District board President Don Lee — who is also a member of the CAP — said he also had no recollection of the issue coming before the City Council, which is what should have occurred.

“Clearly, the Fire Department knew about it and drank the Kool-Aid,” said Lee, who is concerned over the safety of schoolchildren who could be exposed to deadly levels of HF in an accident. “I’m not real happy about this.

“To find out late that they changed it to 10 percent from 30 percent without any public hearing …. really makes me worried about what’s going on inside the fence.”

Former Mayor Dan Walker, who spearheaded the city’s fight to make the refinery safer, said he found it difficult to believe the lack of disclosure to elected officials and the general public of the actual danger posed by the refinery over a 15-year period.

“I cannot imagine our council accepting the type of (additive) reduction that’s being discussed now,” he said. “LeRoy is about as honest as they come and he would not jeopardize the city, the people in the city or himself by any type of lie.”

Apparently under EPA scrutiny is a subsection of the RMP, known as an Offsite Consequence Analysis, that details a worst-case disaster scenario at a chemical plant usually involving an explosion, fire and/or release of a toxic chemical.

Because of security concerns, details of the deaths and injuries that could occur in such an event are not made readily available to the public, and government officials often use that to justify withholding information.

Jackson, for instance, provided a link to Department of Homeland Security “Chemical-terrorism Vulnerability Information.”

The Web page says such information is “withheld from public disclosure … except in exigent or emergency circumstances.”

Nevertheless, TRAA researcher Sally Hayati uncovered the issue by comparing the Offsite Consequence Analysis of the ExxonMobil Torrance refinery with one produced by Valero’s Wilmington refinery.

Both refineries are similar in the amount of gasoline they produce and both use 10 percent MHF, according to the respective RMP’s, Hayati said. Yet the ExxonMobil worst-case scenario is for an HF release of just 5,200 pounds, while Valero’s is 55,000 pounds.

That huge discrepancy also could translate into the difference between hundreds if not thousands of injuries or deaths.

Ron Koopman, a now-retired expert on HF and hazardous materials who previously conducted ground-breaking experiments on behalf of the gasoline industry during a 30-year career, called Hayati’s research “terrific.”

But he was bemused by the different outcomes.

“It looks like these two refiners have picked two very different consequences for what could be a very similar accident,” he said. “Both of those Offsite Consequence Analyses couldn’t possibly have been using the (EPA-approved) guidelines correctly.”

In a statement, ExxonMobil said it followed procedure.

“We submitted our most recent Risk Management Plan (RMP) Worst-Case Scenario (WCS) description to the U.S. Environmental Protection Agency (EPA) in August 2014 that includes information regarding MHF,” spokeswoman Gesuina Paras said via email. “Our RMP WCS is calculated based on methodology defined by EPA.

“If and when EPA carries out inspections as part of their regulatory oversight, we fully cooperate with the agency,” she added. “Regarding the (court-ordered) consent decree with the city, any changes to the initially court-approved terms are governed and must be approved by the court.”

Paras did not address whether the city and company had violated that court order or whether the court had signed off on the reduction in the additive in HF used at the plant.

The company routinely claims it complies with regulatory agencies, something lawmakers and environmental critics have repeatedly said is not the case.

Experts concur that it’s unclear just how much safer MHF is over unmodified acid anyway; Koopman said there has never been a rigorous academic peer review of the chemical because of its proprietary nature.

The combination of the unknowns associated with dangerous MHF, its use in the highly populated South Bay, inadequate regulatory oversight and the safety record of ExxonMobil troubles experts and federal officials.

ExxonMobil is under investigation by the U.S. Chemical Safety Board, Cal/OSHA and now the EPA as well as possibly the Department of Justice for “wilful” violations of environmental laws and regulations and failing to comply with government subpoenas trying to get to the bottom of the multinational corporation’s safety record.

The company also is reportedly believed to have hidden what it knew about climate change and attempted to profit from it, outraging the environmental community and legislators like South Bay Rep. Ted Lieu. Lieu, Rep. Maxine Waters and other lawmakers have repeatedly called for a federal criminal investigation into the company and its top executives.

Given ExxonMobil’s safety record, the thought of the refinery using a potentially lethal chemical concerns activists like Jim Tarr, president of Rolling Hills Estates-based Stone Lions Environmental Corp. Tarr, who has almost four decades of experience evaluating toxic chemical and air pollution exposure, said he brought Hayati’s research to the attention of EPA officials, prompting the investigation.

“The greatest gift the community could receive from ExxonMobil would be the complete elimination of the use of HF, MHF or any other form of HF at the Torrance refinery,” Tarr said. “The next greatest gift would be for ExxonMobil to share the technical details of the MHF system at the refinery with community members, so that the truth of the matter with respect to the lethal risk to the community created by the use of MHF could be known.”

That’s unlikely to occur.

Hayati and Lee said they questioned refinery manager Brian Ablett about the reduction of the additive in the MHF used by the refinery at a recent CAP meeting and didn’t get an answer.

That kind of non-response does not engender a great amount of confidence among experts.

Neither does apparent regulatory paralysis.

For instance, the U.S. Chemical Safety Board that oversees the industry is in a state of disarray and largely unable to function, said Jeff Ruch, executive director of a nonprofit called Public Employees for Environmental Responsibility.

“Given the subsequent implosion at CSB, there is no current movement to address, let alone avert, these potential disaster scenarios,” he said. “As a result, the federal government lacks any realistic way to check even massive risks to the community.”

Yet ExxonMobil is still allowed to operate.

Last week, the California Division of Occupational Safety and Health lifted an order prohibiting the use of the crippled fluid catalytic cracking unit and electrostatic precipitator that exploded in February, Reuters news service reported.

The blast literally rocked the community, showered neighborhoods with insulation debris and sent gasoline prices soaring in the state.

In its wake Cal-OSHA cited ExxonMobil 19 times for deliberately failing to fix equipment over almost a decade the company knew could cause a life-threatening explosion and levied more than $500,000 in fines.

Yet the Nov. 24 action by Cal-OSHA clears the way for ExxonMobil to repair the damaged equipment and restart full-scale gasoline production. That’s a condition of the pending $530 million sale of the property to independent refiner PBF Energy.

Cal-OSHA’s decision also comes before a Dec. 7 prehearing teleconference in which ExxonMobil is appealing the citations.

Neglected safety issues and lack of regulatory oversight are themes Koopman and other industry critics say they have seen before.

“Why the hell are they still here and why hasn’t the government played a more effective role as a regulator in order to rein in an industry which we know is motivated primarily by profit and only secondarily by safety?” Koopman said. “The reason the government hasn’t been able to do that is because there hasn’t been enough money for those parts of government that do that regulating.

“The same hazards exist, the same risk exists, it hasn’t been fixed and it needs to be fixed.”