Hydrofluoric Acid
Hydrofluoric acid (HF) differs from other acids because it readily penetrates the skin and dissociates into fluoride ions, causing destruction of deep tissue layers, including bone. Pain associated with skin exposure to HF may not occur for 1-24 hours. Unless you can rapidly neutralize the HF and bind the fluoride ions, tissue destruction may continue for days and result in limb loss or death. Hydrofluoric acid vapors are also an inhalation hazard and can cause ocular irritation.
Ensure that non-expired calcium gluconate antidote is on hand before handling HF. Always handle HF in a properly functioning laboratory hood and in an area equipped with an eyewash and safety shower. Never work with HF alone.
Required Personal Protective Equipment
- Goggles
- Face shield (plastic)
- Acid resistant apron
- Long pants and sleeves
- Closed toe shoes
- Gloves: Thin disposable gloves (such as 4, 6, or 8 mil blue nitrile gloves) used in laboratory operations provide a contact barrier only and should be disposed immediately when contamination is suspected. Thicker (10-20 mil) PVC or neoprene gloves provide better resistance but do not provide the necessary dexterity for many lab procedures. Thinner PVC or poly gloves can provide some resistance to HF, but require immediate changing at the first sign of contamination. Do not wear disposable gloves without double gloving because of the potential for exposure through pinholes
In the Event of a Skin or Eye Exposure to HF
- Have someone call 911 immediately, to facilitate arrival of medical assistance.
- Remove all exposed clothing and immediately wash all exposed areas with copious amounts of water from the safety shower or eyewash. Flush exposed eyes for at least 15 minutes, but flush exposed skin for only five minutes, followed by treatment with a calcium source.
- For skin exposures, after flushing for five minutes, apply a gel or slurry of calcium gluconate (preferred) or calcium carbonate directly to the exposed area. Use concentrations between 2.5% and 33%.
Spills
Ensure all areas where HF is used are equipped with proper spill response equipment. You can neutralize small spills (100 mL or less) by covering with magnesium sulfate (dry) and absorbing with spill control pads or other absorbent materials. Add sodium bicarbonate or magnesium oxide to any absorbent and place in a plastic container for disposal. Wash the spill site with a sodium bicarbonate solution. Use 3M’s Universal Sorbent or similar, as it does not react with HF. Do not use spill sorbents that contain silicon, such as vermiculite or sand, as this can produce silicon tetrafluoride, an odorless toxic gas. If the spill is large, in a confined space, or in an area where there is not adequate ventilation, evacuate the room and immediately report the spill to 911.
Contact EHS at 919-962-5507 if you have questions about spill response, or if you do not feel comfortable trying to clean up the spill yourself.