Eleven years after a refinery blast rattled homes across the South Bay, the same controversial chemical at the heart of that near miss is still in use, and Torrance leaders say they have had enough. The target is modified hydrofluoric acid, or MHF, which activists describe as a ground-hugging, flesh-eating vapor that can travel for miles and cause deep tissue and lung damage. The anniversary has ramped up pressure on regulators and refinery owners to swap out MHF-based alkylation units for safer technologies.
In a Facebook reel, Los Angeles County Supervisor Janice Hahn did not mince words, warning that "MHF is simply too dangerous to use" and calling it a "flesh eating, low crawling, toxic vapor cloud." Her remarks came during an 11th anniversary teach in marking the Feb. 18, 2015 explosion, an event the Los Angeles Times revisited this week.
The 2015 Near Miss That Still Haunts Torrance
The U.S. Chemical Safety Board investigation found that debris from the Feb. 18, 2015 blast struck scaffolding near the refinery’s alkylation unit and came dangerously close to a tank holding tens of thousands of pounds of modified hydrofluoric acid. It was a scenario that "could have been far worse," according to the U.S. Chemical Safety Board. Investigators cited multiple process safety management failures and warned that a release of HF or MHF would likely form a dense, ground hugging cloud capable of causing severe burns and respiratory collapse.
Why MHF Terrifies Activists
Hydrofluoric acid, and the "modified" version refineries insist is safer, reacts with moisture to create a low lying vapor that can dissolve tissue and fat and fatally damage lungs, the Natural Resources Defense Council warns. Local regulators point out that only two Southern California refineries, the Torrance plant and Valero’s Wilmington refinery, rely on MHF. Both facilities submitted voluntary safety proffer letters to the South Coast AQMD when the agency reviewed refinery controls in recent years.
Refineries Say They Have Safety Covered
Refinery operators counter that they have layered on barriers, monitoring systems and mitigation measures aimed at reducing both the chances of a release and its fallout. Company representatives and local reporting note that Torrance Refining Company, now owned by PBF Energy, has worked closely with regulators and says it has produced alkylate with HF and MHF for decades without an off site release, according to FOX 11 Los Angeles.
Lawmakers, Lawsuits And A Long Timeline
Advocates are pushing on multiple fronts, from local rulemaking to federal action. Lawmakers have floated proposals that would require refineries to convert away from HF and MHF, a campaign the Los Angeles Times reported, while community groups have filed petitions and lawsuits urging the EPA to reassess HF’s risks, according to the Natural Resources Defense Council. Draft bills and South Coast AQMD deliberations could give refineries years to make the switch if new rules pass, but activists argue that such long timelines leave far too many people living inside modeled hazard zones.
For neighbors who still remember the ash falling and alarms blaring in 2015, the fight over MHF is not abstract. Organizers say they plan to keep up rallies, public records requests and relentless community outreach in an effort to push regulators and lawmakers toward what they see as safer alternatives.
