Hydrofluoric Acid
Hydrofluoric acid (HF) is a weak acid in the chemical sense but a terrible one for people. It penetrates skin, attacks deep tissue and bone, and the fluoride that enters the body can disturb the heart and kill. Pain can be delayed for hours, so an exposure may be missed.
- Industrial
- Cleaning & Car Wash
- Oil & Gas
Where it is found
- Wheel and aluminum brighteners, rust removers and some heavy-duty cleaners (including products with ammonium bifluoride). See Car Washes.
- Glass etching, semiconductor manufacturing and metal pickling.
- Petroleum refining (alkylation units) and chemical plants.
- Laboratories.
Why it is so dangerous
- HF passes through skin quickly. The fluoride ion binds calcium and magnesium in the body.
- A small burn of a few percent of body area can lead to life-threatening low calcium, heart rhythm problems and death.
- Low concentrations may cause no immediate pain; severe pain develops later.
- Vapors and mists can burn the eyes, throat and lungs.
Preventing exposure
- Substitute safer products when possible. Read the label and SDS to identify HF or fluoride ingredients. See Safety Data Sheets.
- Use chemical-resistant gloves (neoprene or butyl, with outer and inner pairs), apron, boots and splash goggles with a face shield. Check the SDS and glove chart. See Chemical Protective Clothing.
- Use in ventilated areas. Do not mix with other chemicals.
- Train workers on first aid and keep 2.5 percent calcium gluconate gel within reach where HF is used.
- Have an eyewash and safety shower close, tested regularly. See Eyewash & Showers.
- Store in plastic (not glass) containers designed for HF, away from incompatibles. See Chemical Storage.
If exposed
- Get away from the source. Flush with water for at least 5 minutes (skin) or 15 minutes (eyes) while removing contaminated clothing.
- Apply calcium gluconate gel to the skin after rinsing, as trained, wearing gloves. Keep applying.
- Call 911 and go to the hospital for any significant exposure, even if there is little pain. Tell medical staff it is hydrofluoric acid and bring the SDS.
- For inhalation, move to fresh air and get oxygen from trained staff.
- Do not wait for pain.
Standards & references
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