Hydrofluoric acid (HF) is a corrosive and toxic acid that can cause serious burns, blindness and even death.
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
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
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
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.
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.
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
WorkSafe Advisory Service
WorkSafe's advisory service is available between 7:30am and 6:30pm Monday to Friday. If you need more support, you can also contact WorkSafe using the Translating and Interpreting Service (TIS National) or the National Relay Service.