Hydrofluoric Acid Awareness Training

1. Hydrofluoric Acid Awareness Training Version Jan 2011

2. Contents Locations within the School of Engineering where the use of HF is permitted. What is HF and why is it harmful? Medical effects of HF exposure. Personal Protective Equipment. First Aid treatment for HF exposure.

3. Permitted Areas of Use Within the School There are only 3 areas within the School that have been designated for the use of HF. These are: SMC Bay 8 and analytical labs Flemin Jenkins AD Cab lab In addition, all work may only be undertaken by competent persons wearing full PPE within a suitable fume cupboard or wet deck.

4. What if Hydrofluoric Acid? Hydrofluoric acid (HF) is a mineral acid, similar to HCl, H2SO4 or HNO3. In the acidic solution there are H+ and F- ions. Like every other mineral acid, HF is corrosive but unlike the other acids, the most significant risk results from the toxicity of the F- ions. HF readily attacks glass so must only be used with the appropriate beakers, i.e. those made from materials such as PFA, PE etc.

5. Medical Effects of HF Exposure HF is a highly corrosive acid which can severely burn skin, eyes, and mucous membranes. The vapours from anhydrous hydrofluoric acid or its concentrated solutions can also burn these tissues. HF is similar to other acids in that the initial extent of a burn depends on the concentration, the temperature, the duration of contact with the acid and the size of the burn. Hydrofluoric acid differs, however, from other acids because the fluoride ion readily penetrates the skin, causing destruction of deep tissue layers. Unlike other acids which are rapidly neutralized, this process may continue for days if left untreated. From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on the SMC wiki and also in the HF burns kit.

6. Medical Effects of HF Exposure Strong acid concentrations (over 50%), and particularly anhydrous HF (AHF or 100% HF), cause immediate, severe, burning pain and a whitish discoloration of the skin often followed by blister formation. Skin exposure to HF vapours can result in similar burns. HF skin burns are usually accompanied by severe, throbbing pain which is thought to be due to irritation of nerve endings by increased levels of potassium ions entering the extracellular space to compensate for the reduced levels of calcium ions, which have been bound to the fluoride. Relief of pain is an important guide to the success of treatment. From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on the SMC wiki and also in the HF burns kit.

7. Medical Effects of HF Exposure The usual initial signs of an HF burn are redness, edema, and blistering. With more concentrated acids, a blanched white area appears. The fluoride ion penetrates the upper layers of the skin. A thick granular exudate may form under blisters due to liquefaction necrosis. In rare (and untreated) cases, there may be penetration to underlying bone with decalcification. HF burns require immediate and specialized first aid and medical treatment differing from the treatment of other chemical burns. If untreated or if improperly treated, permanent damage, disability or death may result. If, however, the burns are promptly and properly recognized and managed, the results of treatment are generally favourable. From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on the SMC wiki and also in the HF burns kit.

8. Personal Protective Equipment (PPE) Our philosophy is create a environment in which we minimise the risk from HF exposure. We have put in place engineering controls (wet decks and fume cupboards), provided training (this presentation and other forms) and finally provided PPE as a last resort. All users of HF must wear PPE and the following are provided in the cleanroom. Full face visor. Protective apron. Chemical resistant gloves.

9. HF Spills A small spill of HF that is contained within the wet deck can be simply washed away with water but make sure that all the HF has been removed. Larger spills or a spill of any amount of HF outside of the wet deck should is significant. In this instance, evacuate the cleanroom by sounding the “smell bell” located outside bay 8. If possible open the wet decks to help extract the area. Contact the technical staff and clean room manager informing them of the details of the incident. Do not re-enter the cleanroom until the spill has been dealt with and the area declared safe.

10. HF First Aid - General All exposure to HF should receive immediate first aid and medical evaluation even if the injury appears minor or no pain is felt. All helpers must wear appropriate PPE to avoid further casualties. Once first aid has been started, get medical assistance by calling 2222 from any University phone. Do not stop first aid treatment until told to do so by a medical professional.

11. HF First Aid – Skin Burns Immediately place the patient under the safety shower and wash off the acid. Speed and thoroughness are paramount. Arrange for immediate medical treatment by Calling 2222 from any University phone. Remove any contaminated clothing but do not stop washing the effected site of the burn with water. After at least 5 minutes of washing under the safety shower, apply calcium gluconate gel and massage into the effected site. Keep applying the gel and massaging the site until told to stop by the medical professionals.

12. HF First Aid – Eye Exposure Immediately begin to gently flush the eye with water. Arrange for immediate medical treatment by Calling 2222 from any university phone. Remove any contact lenses but don’t interrupt the flushing. Hold the eyelids open and away from the eye. Continue to flush with water for at least 15 minutes or told to do so by a medical professional.

13. HF First Aid - Inhalation Immediately evacuate the patient to an area of fresh air. Arrange for immediate medical treatment by Calling 2222 from any university phone. Administer medical oxygen if trained to do so.

14. HF First Aid - Ingestion Have the patient drinking large quantities of milk (preferable) or water to dilute the acid. Arrange for immediate medical treatment by Calling 2222 from any university phone. Do not induce vomiting. Never give anything my mouth to an unconscious patient.

15. First Aid Summary From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on the SMC wiki and also in the HF burns kit.

16. HF Safety Equipment There are safety showers located in or adjacent to all areas in which HF is used. A HF burns kit has been provided. The kit contains: • Nitrile protective gloves. • Calcium gluconate gel • HF MSDS and the Honeywell publication “Medical Treatment for Hydrofluroic Acid Exposure” which should be sent with the patient to hospital. A medical oxygen kit is located in the changing room.

17. Further Training The next step in the training is to go into the cleanroom and look at the facilities and safety systems in place. Finally instruction will be given in the correct usage of the wet decks.

18. Summary • HF should be treated with the utmost respect. • Always assume the HF bench is contaminated and always clean up thoroughly after you use it. • Never work alone with HF. • Avoid overcrowding around the area. • Only use the area if absolutely necessary. • Only use polypropylene beakers and utensils with HF. • Use the Calcium glutamate gel if you suspect any type of contact with HF. • If you use the gel inform and take the tube with you for further applications. • Familiarise yourself with the first aid procedures as you may be called upon to assist at any time.