Environmental, Health and Safety Services

Hydrofluoric Acid

Health Hazards

Eye and skin exposure

Hydrofluoric acid (HF) is corrosive and readily destroys tissue. Exposure of the eyes may result in blindness or permanent eye damage. HF readily penetrates human skin, allowing it to destroy soft tissues and decalcify bone. Chemical burns from HF are typically very painful and slow to heal. Skin exposure to highly concentrated HF (approximately 50% or greater) immediately results in serious and painful destruction of tissue.  Death can result from burns involving less than 2.5% of the skin surface.
HF at lower concentrations may not produce pain or burning sensations until hours after the exposure. A victim may suffer severe delayed tissue damage without noticing appreciable pain.  Every skin, eye, or tissue contact with HF should receive immediate first aid and medical evaluation, even if the injury appears minor or no pain is felt.

Inhalation of HF vapor

Inhaling HF vapors can seriously damage the lungs. Delayed reactions such as pulmonary edema may not be apparent for hours after the initial exposure. Airborne concentrations of 10 to 15 ppm will irritate the eyes, skin, and respiratory tract.  Airborne concentrations of 30 ppm are considered immediately dangerous to life and health (IDLH) and may have irreversible health effects. At airborne concentrations above 50 ppm, even brief exposure may be fatal.

Information and Training

Employee Information and Training

HF is a colorless liquid with a strong irritating odor at low concentrations (3 ppm). Employees who handle HF must receive documented training on the hazards of HF and what to do in the event of an exposure or a spill. A Material Safety Data Sheet (MSDS) on HF should always be kept in the immediate work area where HF is used.

Engineering Controls

Ventilation

HF should be used with adequate ventilation to minimize inhalation of vapor. Concentrations greater than 5% should always be handled inside a properly functioning chemical fume hood.

Personal Protective Equipment

Eye Protection

Always use chemical splash goggles together with a face shield when handling concentrated HF. Due to HF’s highly corrosive nature, safety glasses with side shields do not provide adequate eye protection.

Body Protection

Wear a laboratory coat with a chemical splash apron made out of natural rubber, neoprene, or other suitable material.  Consult the MSDS for appropriate protective material.

Gloves

Consult the manufacturer’s glove selection guide in conjunction with the MSDS when selecting a glove for HF. If you have any questions about which glove to choose, contact EHS.  If gloves become contaminated with HF, remove them immediately, thoroughly wash your hands, and check your hands for any sign of contamination. Contaminated gloves must be disposed of as hazardous waste.

First Aid and Emergency Procedures (also refer to MSDS)

Eye exposure

Immediately irrigate eyes at eyewash for at least 15 minutes with copious quantities of water keeping eyelids apart and away from eyeballs. Do not apply calcium gluconate gel to eyes. In all cases of eye exposure seek prompt medical attention.

Skin Exposure

Immediately wash affected area of skin at sink if a small area of hand or forearm has been contaminated or at a drench shower if upper arms, torso, or legs are contaminated. Remove all contaminated clothing and place in hood or plastic bag.   If calcium gluconate gel is readily available, limit rinsing to 5 minutes and apply calcium gluconate gel.  Reapply calcium gluconate gel into affected area of skin every 15 minutes.  Every lab area using concentrated HF must have a ready supply of fresh calcium gluconate gel.  In all cases of skin exposure seek prompt medical attention.

  • Note: Calcium gluconate gel is a topical antidote for HF skin exposure. It works by combining with HF to form insoluble calcium fluoride, thus preventing the extraction of calcium from tissues and bones. Keep calcium gluconate gel nearby whenever you’re working with HF. Calcium gluconate has a limited shelf life and should be stored in a refrigerator if possible and replaced with a fresh supply after its expiration date has passed. Use disposable gloves to apply calcium gluconate gel.

Ingestion

Drink large amounts of water to dilute. Do not induce vomiting. Several glasses of milk or several ounces of milk of magnesia may be given for their soothing effect. In all cases of ingestion seek prompt medical attention.

Inhalation:

Move victim to fresh air.  Exposure to HF by inhalation is particularly dangerous.  In all cases of overexposure through inhalation seek prompt medical attention.

Handling and Storage

Safe Work Practices

Never work alone when using concentrated solutions of HF. Wash hands thoroughly after handling HF and practice good clean-up habits.

HF Spills

If HF is spilled outside a chemical hood:

  • Evacuate the area.
  • Close the doors.
  • Post the area with a sign to prevent others from entering.
  • Call 911 to notify EHS. 

Small spills of HF inside a chemical fume hood can be cleaned up by laboratory staff if they have the correct equipment, understand the hazards, and are confident in their ability to clean up the spill safely and dispose of the waste properly. Lime soda, ash, sodium bicarbonate, or a spill absorbent specified for HF should be used for clean up. Organic spill kits that contain Floor-Dri, kitty litter, or sand should not be used because HF is a powerful oxidizer and HF reacts with silica to produce silicon tetrafluoride, a toxic gas.

Storage

Store all HF and HF waste in labeled chemically compatible containers (e.g. polyethylene or Teflon). Glass, metal, and ceramic containers are not compatible with HF. HF should never be stored with incompatible chemicals such as ammonia or other alkaline materials. Store all acids and corrosive materials below eye level.

Waste

HF waste should be placed in a chemically compatible container with a sealed lid, clearly labeled, and properly disposed of through EHS.