Using hydrofluoric acid in the workplace

The risks

Depending on the concentration, exposure to HF can cause death. The main cause of death is from the fluoride in HF entering the bloodstream, trapping calcium and magnesium and quickly damaging the heart, muscles and nervous system.

Skin contact with concentrated solutions of HF can cause severe burns and death. Diluted solutions can also penetrate the skin without an immediate burning sensation, so workers may not be aware they’ve had contact with the acid. Once HF enters the body, it continues causing damage even after washed off.

Eye contact with HF can quickly cause blindness or permanent eye damage.

Exposure through inhalation would not be a risk unless spraying HF or handling concentrated fuming HF greater than or equal to 40%.

Reducing risks in the workplace

The risks associated with handling HF products can be eliminated or reduced in the following ways.

Eliminating the use of HF

• outsource the work to someone who has the right controls and equipment to use HF
• using an abrasive blasting or mechanical cleaning technique

Using safer products

• using safer chemical or a milder acid
• using less concentrated HF
• buying HF in ready-to-use concentrations to avoid handling the concentrate
• buying HF in smaller containers that are easier to handle

Separating employees from HF and any potential splashing

• using a winch to slowly lower and raise items from a distance in large tank dipping operations
• using splash barriers if needed
• keeping unnecessary people away from the work area

Using safer methods or processes

• using an automated dispensing and diluting system that takes the HF directly from a drum to minimise the potential for contact.
• preparing HF in situ in the tank at the required concentration by using a fluoride salt and a different  acid
• using a mechanical devise to support the container while pouring
• fitting a pouring device to the container to minimise any splashing
• using safer application techniques to prevent splashes or contact

Engineering controls

• Providing appropriate mechanical ventilation when spraying HF solutions or using fuming HF greater than 40%

Following safe work practices

• cleaning more frequently with a milder chemical to prevent build up
• rinsing parts that have been in contact with HF to prevent skin contact
• when diluting HF, always add acid to water, never water to acid
• do not work alone when handling HF solutions greater than 10% HF

Good housekeeping practices

• placing lids or caps on tanks and containers of HF
• cleaning the work area regularly
• cleaning up spills immediately
• displaying signs warning of the presence and hazards of HF

Personal hygiene

To prevent getting HF on your skin or food, wash hands and face regularly at the end of each task, before eating, drinking and smoking, and before going to the toilet

Personal protective equipment (PPE)

Using appropriate PPE such as:

• nitrile or natural rubber gloves
• PVC apron
• face shield or eye protection
• respirator with an acid-gas filter when spraying HF or handling HF greater than or equal to 40%

Also ensure PPE is thoroughly cleaned with water after use and checked for any damage such as holes in gloves.

Information, instruction and training

• current safety data sheet (SDS) is available
• label tanks and containers of decanted HF products to identify contents
• train employees on how to use HF safely

First aid and emergency facilities

Employers need to ensure:

• there are documented emergency and first aid procedures
• calcium gluconate gel (antidote) is available, stored below 25°C and within the expiry date
• plumbed-in eye wash and shower equipment is close to where HF is used, particularly for HF concentrations equal to or greater than 1%
• first aiders are trained to deal with HF incidents.
• local hospitals and clinics are informed and equipped to treat HF exposure

What to do after contact with HF

Skin and eye contact with HF is an emergency that needs to be treated immediately to minimise the risk of serious health effects and loss of sight.

Eye contact

• flush the eyes for at least 15 minutes using a plumbed-in eye wash
• seek medical advice or attention

Note: An eye wash bottle should only be used as an interim flushing solution until the worker can reach a plumbed in eye wash.

Skin contact

• immediately remove any contaminated clothes and wash the affected area for at least 15 minutes
• apply calcium gluconate gel antidote to the affected skin area
• seek medical advice or attention

Note: Hose down heavily contaminated clothing or place in a trough of water with at least one heaped tablespoon full of sodium bicarbonate (baking soda) to neutralise it.

Storing hydrofluoric acid

When storing HF, ensure it is:

• out of direct sunlight in a well-ventilated, cool, dry area
• stored at or near ground level on corrosion-resistant surfaces
• well-marked so it cannot be confused with other acids with similar sounding name such as hydrochloric
• separated from solvents and other acids such as alkalis, flammable liquids, pool chlorine to prevent a fire, chemical reaction or explosion
• bunded to contain any spills or use a pallet bund

Disposing of hydrofluoric acid

• avoid stockpiling HF and dispose of any HF correctly when it’s not needed
• do not tip waste down the drain
• label waste containers to identify HF waste and the approximate concentration or concentration range