Purpose and Instructions

This standard operating procedure (SOP) template is intended to be used to create a lab specific SOP for aqueous Hydrofluoric Acid (a.k.a. HF) use. This SOP is not considered to be complete until the lab information above is filled out, the protocol/procedure section is updated, and the PI has signed it. All employees who work with hydrofluoric acid must read this SOP and sign this document (on the last page) or your annual lab specific training log to document completion. Records must be kept for 5 years. 

If you have any questions about writing SOPs, chemical safety, hazard assessments, or any other research safety questions, contact your Departmental Safety Officer (DSO) or your HSRM Research Safety Partner ([email protected] or (612) 626-6002). 

Note: this template DOES NOT apply to procedures involving gaseous HF (hydrogen fluoride). If you plan to conduct experiments with gaseous HF, you must contact your HSRM Safety Partner before doing so.

Hazard Identification

Hydrofluoric acid is both corrosive and acutely toxic. Hydrofluoric acid poses health risks from acute and chronic inhalation and dermal exposures. Short-term effects may include severe eye irritation, nose and throat irritation. Contact with skin can cause irritation and severe deep tissue burns which may not be evident for several hours. Long-term exposures may result in damage to the liver and kidneys or bronchitis due to repeated inhalation. Prolonged exposure to high concentrations can increase the risk of developing “Fluorosis”, the deposit of fluoride in the bones and teeth. 

Engineering Controls and Personal Protective Equipment (PPE)

Engineering Controls

• Use of hydrofluoric acid must be conducted in a properly functioning chemical fume hood. The chemical fume hood must be approved and certified within the past 12 months. The certification date can be found on the certification sticker placed on the fume hood by HSRM staff. The fume hood must be labeled to indicate work with HF is performed in the area.

Hygiene Measures 

• Avoid contact with skin, eyes, and clothing. Wash hands before breaks and immediately after handling the product. Remove any contaminated clothing.

Hand Protection

• For brief use of dilute solutions, workers must wear (at a minimum) 8 mil nitrile gloves. When working with strong concentrations (30-70%), workers must wear Butyl or Neoprene gloves. Always consult the manufacturer to ensure that the gloves you plan on using are compatible with the specific chemical being used. 

Eye Protection

• ANSI approved, properly fitting chemical splash goggles are required. A face shield must be worn over safety goggles when working with strong concentrations, large quantities, or there is a possibility of splashes.

Skin and Body Protection 

• Laboratory coats must be worn and buttoned to their full length. Laboratory coat sleeves must be of sufficient length to prevent skin exposure while wearing gloves. Personnel must also wear full-length pants, or equivalent, and close-toed shoes always when occupying the laboratory area. The area of skin between the shoe and ankle must not be exposed. If working with large quantities or there is a possibility of splash, a full body chemical-resistant apron must also be worn.

Special Handling and Storage Requirements 

• Handle in accordance with the requirements established in the protocol section below.
• Fresh antidote gel (2.5% calcium gluconate) must be available and stored at the procedure location prior to any experiment being conducted. Calcium gluconate gels do not have a long shelf life. Check the expiration date on the tube periodically and replace it when necessary.
• Keep containers tightly closed until used.
• HF is a corrosive, inorganic acid and must be stored in a corrosives cabinet and in secondary containment made of a compatible material, such as polyethylene. The cabinet must have warning signs posted outside of it.
• Keep HF away from the following:
  • Glass
  • Ceramics
  • Concrete
  • Most metals
  • Bases and alkaline chemicals
  • Organics
  • Oxidizers
• HF is not compatible with glass and will easily dissolve it. Always store or use in compatible containers, such as those made of polyethylene or Teflon.
• Store only necessary quantities of HF in the lab. It is strongly recommended to order small bottles (500 – 1000 mL) that allow for easy transfer (pouring) to other containers.
• Have a neutralizing agent (base) nearby in case of a small spill. A dedicated HF spill kit is strongly recommended.
• Transport HF in secondary containment equipped with a closing lid.

Spill and Accident Procedures

• If the chemical contacts exposed skin, gently wash with running water and non-abrasive soap. Using appropriate protective gloves, apply a generous amount of 2.5%  calcium gluconate gel to the exposed area and continue applying until medical help arrives. A medical evaluation must take place after any exposure to HF.
• If there is HF exposure to the eye(s), immediately go to an eyewash station and rinse for 15 minutes.
• An HF-specific first aid kit is required for labs working with hydrofluoric acid.
• In the event of a small spill (in the hood), immediately add a neutralizing agent, such calcium carbonate or sodium bicarbonate. After the HF has been neutralized, clean up and dispose of as you would any other hazardous spill.
• Any HF spills outside of the fume hood or of a large quantity should be treated as an emergency. Immediately evacuate the area and ensure others are aware of the spill. If personnel have become exposed and need medical assistance, dial 911. If the spill is outside the fume hood and does not pose a threat to personnel, immediately evacuate the area. Contact HSRM for spill cleanup and decontamination assistance.
• Report any work-related exposure by completing an electronic first report of injury form. This initiates the worker’s compensation process and ensures your consultation will be covered by the University of Minnesota. You will receive an email confirmation with a 9-digit claim number, which must be referenced to schedule the consultation. 

Waste Disposal Procedures

• It is best practice to collect hydrofluoric acid waste in dedicated containers.
• HF can dissolve glass. Collect HF waste in a polyethylene or Teflon container.
• Store HF waste in containers that are properly labeled and in a designated area away from incompatible chemicals (a corrosives cabinet is recommended). Post a warning sign at this designated location.
• More information on hazardous waste procedures and pick-up can be found on the HSRM Regulated Waste website.