Why Is Hydrofluoric Acid So Dangerous?

Just before 9 a.m. on February 18, 2015, the city of Torrance, California, came just feet from calamity. An explosion rocked the 750-acre ExxonMobil refinery, injuring 2 workers and scattering debris around the facility and the nearby community.

As dramatic as it was, however, it could have been much worse.

The blast originated inside the fluid catalytic cracking (FCC) unit’s electrostatic precipitator—a pollution control device that routinely generates internal sparks. Investigators from the U.S. Chemical Safety Board (CSB) later found that hydrocarbons had backflowed into the precipitator and ignited because the refinery was operating the FCC unit in an improvised “Safe Park” standby mode without pre-defined pressure limits or reliable safeguards.

The explosion hurled an 80,000-pound chunk of steel into the air. It landed mere feet from storage vessels holding thousands of gallons of modified hydrofluoric acid (HF), a highly toxic chemical that can be lethal at concentrations as low as 30 ppm. Had the debris ruptured those tanks, Torrance and neighboring communities could have faced a release of hydrofluoric acid vapor capable of causing mass injuries or deaths.

According to the CSB’s final report, refinery management reused a deviation procedure drafted for a 2012 maintenance job without re-evaluating the hazards. Critical equipment—already beyond its predicted safe operating life—was left in service, and no instrumentation was in place to detect flammable gases flowing toward the precipitator. In short, layer after layer of process-safety protections had been stripped away.

Hydrofluoric Acid: What It Is & Where It’s Used

Hydrofluoric acid is a water-based solution of hydrogen fluoride gas. Unlike most mineral acids, hydrofluoric acid is highly volatile and readily penetrates skin, where it binds aggressively with calcium and magnesium deep in tissue and bone. Because of this unique chemistry, even small splashes can cause excruciating “latent” burns that worsen for hours and lead to systemic toxicity, cardiac arrest, or death if calcium-based antidotes are not administered immediately.

Hydrofluoric acid’s ability to dissolve silica makes it invaluable to industry—but the very property that etches glass also dissolves human bone.

Hydrofluoric acid is used in the alkylation units of refineries to produce alkylate, a blending component that helps gasoline burn cleaner. Specifically, hydrofluoric acid is used as a catalyst in the production of this substance. More than a third of the refineries in the United States use hydrofluoric acid as a catalyst. Hydrofluoric acid isn’t just used during gas production, it’s also used to produce refrigerants, herbicides, aluminum, pharmaceuticals, fluorescent light bulbs, and plastics. Hundreds of industrial sites across the country store or process significant hydrofluoric acid inventories, placing surrounding communities on the front line of potential disasters from chemical spills, chemical plant explosions, chemical fires, and more.

When hydrofluoric acid is released under pressure, it can flash into a dense, ground-hugging vapor cloud. That cloud does not disperse upward like typical refinery flares; instead, it rolls along the surface, corroding steel, concrete, and organic tissue alike. Workers caught in the plume can suffer deep tissue burns through protective clothing, and residents blocks away may experience respiratory failure, eye damage, or fatal systemic poisoning.

Because hydrofluoric acid vapor is colorless and its irritation can be delayed, people may not realize they have been exposed until irreversible injury has already begun, making rigorous containment, real-time detection, and emergency response plans absolutely critical.

What Does Hydrofluoric Acid Do to People?

Hydrofluoric acid is far more dangerous than most industrial acids because once it contacts the body, it behaves like a chemical and biological weapon rolled into one. The acid rapidly penetrates skin, fat, and even bone, releasing fluoride ions that bind with calcium and magnesium deep in tissue. This process can trigger severe burns, excruciating pain, muscle failure, and potentially fatal cardiac arrest—even from a splash no larger than a quarter. Unlike other acids that cause immediate surface damage, HF burns may take minutes or hours to become painful, allowing serious internal injury to progress unnoticed.

If hydrofluoric acid is inhaled as mist or vapor, it attacks the respiratory tract, causing throat swelling, pulmonary edema, and irreversible lung damage. Ingesting even a small volume can lead to catastrophic organ failure as fluoride ions circulate through the bloodstream, stripping calcium from the heart, kidneys, and nervous system.

The Marathon Petroleum Texas City Hydrofluoric Acid Leak

On Halloween in 1987, residents of Texas City experienced what many in Torrance only narrowly avoided: an actual hydrofluoric acid release.

At about 5:20 p.m., a crane at the Marathon Petroleum refinery lost control of a 40-ton convection heater. The falling load sheared a three-inch line on an adjacent storage tank and instantly released a pressurized stream of hydrogen fluoride gas. Within minutes, a dense cloud drifted low to the ground across roughly 50 city blocks, forcing the emergency evacuation of more than 3,000 people.

Hospitals soon filled with frightened families. More than 800 residents sought treatment for burning eyes, throat irritation, and breathing difficulties, and more than 30 required overnight admission. First responders, many lacking proper hydrogen fluoride PPE (personal protective equipment), worked through the evening while plant crews improvised a transfer to empty the compromised tank and stop the leak.

No fatalities were recorded, but the incident demonstrated how a hydrofluoric acid release can overwhelm community resources and expose thousands to life-altering health risks.

A Concerning String of Hydrofluoric Acid Incidents in Geismar, LA

Hydrofluoric acid hazards are not limited to refineries, nor are they a thing of the past. Honeywell’s fluorochemicals complex in Geismar, Louisiana—one of the nation’s largest producers of hydrofluoric acid and related intermediates—suffered three serious releases in as many years, prompting repeated deployments by the CSB.

June 7, 2024 – A maintenance contractor was exposed to hydrofluoric acid while servicing process equipment, leaving him hospitalized with severe chemical burns.

January 23, 2023 – A heat exchanger ruptured, causing an explosion that released about 870 pounds of hydrogen fluoride and 1,700 pounds of chlorine. The blast caused about $4 million in property damage at the complex and triggered a site-wide shelter-in-place order as well as the closure of adjacent highways. Local responders credited favorable winds with preventing mass civilian exposure.

October 21, 2021 – A Honeywell employee died after a gasket failed, exposing unprotected areas of his face, neck, and ear to hydrofluoric acid. The CSB’s preliminary findings cited degraded gaskets, insufficient PPE, and gaps in air monitoring.

CSB Chairperson Steve Owens has said that the agency will continue to urge regulators to prioritize inspections of facilities that use hydrogen fluoride products.

What Should You Do If You’re at Risk of Hydrofluoric Acid Exposure?

Both hydrogen fluoride and its liquid form, hydrofluoric acid, can be lethal at surprisingly low concentrations. Quick, informed action can make the difference between a full recovery and permanent injury—or worse.

In the event of a hydrofluoric acid or hydrogen fluoride release:

• Move to clean air. Indoors: Evacuate the building quickly if authorities call for it; hydrofluoric acid vapors can settle and concentrate in enclosed spaces. Outdoors: Leave the release zone and move upwind and uphill, as hydrofluoric acid clouds hug the ground.
• Follow official instructions. Emergency managers may issue shelter-in-place orders if the vapor plume cannot be avoided. Close windows and doors, seal cracks with duct tape or wet towels, and shut off HVAC systems.
• Strip and flush. Remove contaminated clothing—including shoes and jewelry—as rapidly as possible. Rinse exposed skin with copious amounts of water for at least 15 minutes. Hydrogen fluoride can penetrate latex and many fabrics, so cut clothing away rather than pull it over unprotected skin.
• Apply calcium gluconate if available. This topical gel or injectable antidote binds fluoride ions and can limit deep-tissue damage. Use only as directed by medical professionals.
• Seek specialized medical care immediately. Symptoms may be delayed, so do not wait for pain or other symptoms. Tell first responders that hydrogen fluoride or hydrofluoric acid was involved so they can activate appropriate treatment protocols.

If you’ve been exposed to hydrogen fluoride, hydrofluoric acid, or any other substance because of the negligence of a company or person, call Arnold & Itkin now at (855) 705-1863 for help. Our plant and refinery accident attorneys have recovered billions of dollars for people suffering because of the recklessness of others, and we’re ready to fight for you.