Hydrofluoric Acid Exposure: An ICU Nurse's Guide

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Updated July 2026  |  More ICU nursing guides →

Hydrofluoric acid (HF) is the exposure that breaks the rules. It is a relatively weak acid by pH, so a splash may cause little immediate pain — and that false reassurance is exactly the danger. HF is found in rust removers, aluminum brighteners, glass-etching solutions, and semiconductor and industrial settings, and even a modest skin exposure to concentrated HF can be fatal from the systemic electrolyte derangement it causes. The ICU nurse's job is to understand that HF is a metabolic poison, not just a burn, and to anticipate the calcium collapse and the arrhythmia that follows.

Why HF is different from other acids

Most acids injure by their hydrogen ion — a surface burn proportional to pH. HF does that too, but its real weapon is the fluoride ion. Fluoride penetrates deep into tissue and then avidly binds calcium and magnesium, forming insoluble salts. This does two things: it destroys tissue from the inside out (causing the classic deep, disproportionately painful burn that can worsen over hours), and it strips the body of ionized calcium and magnesium, producing systemic hypocalcemia, hypomagnesemia, and hyperkalemia. Concentrated HF (roughly >50%) causes immediate pain; dilute HF may not hurt for hours, and patients underestimate it.

Calcium is the antidote

Because fluoride's toxicity is calcium binding, the treatment is to give it more calcium to bind, sparing the body's own. The route depends on the exposure and is provider-directed: topical calcium gluconate gel for skin, calcium gluconate by nebulizer for inhalation, and IV calcium for systemic hypocalcemia. Painful digital or deep burns may be treated with intra-arterial or Bier-block calcium infusions by specialists. The nurse's contribution is early, aggressive electrolyte monitoring and having calcium ready before the numbers crash.

The arrhythmia that kills

The lethal endpoint of HF poisoning is a calcium- and magnesium-depleted, potassium-elevated myocardium that develops a prolonged QT and slides into torsades de pointes, ventricular fibrillation, or arrest — sometimes with alarmingly little skin injury to explain it. Put every significant HF exposure on continuous cardiac monitoring, draw ionized calcium (not just total), magnesium, and potassium early and often, and treat aggressively before the rhythm changes. Have IV calcium and magnesium at the bedside; cardiac arrest from HF often needs far more calcium than a standard code dose, guided by toxicology.

Decontamination first

Before anything else, remove contaminated clothing and irrigate the exposed skin with copious water, protecting yourself with appropriate PPE so you do not become a second casualty. After irrigation, calcium gluconate gel is applied to skin burns. Persistent or worsening pain after topical therapy signals ongoing deep fluoride activity and the need to escalate the route of calcium — pain is one of your best bedside markers that the antidote is not yet keeping up.

For the electrolyte pieces, see hypocalcemia and calcium repletion and the calcium salts in calcium chloride vs. gluconate; for the rhythm, torsades de pointes. Related toxic-exposure guides: caustic ingestion and spider envenomation.