Hydrofluoric Acid

Brown University Environmental Health & Safety Brown University Environmental Health and Safety 401.863.3353

Outline

      Introduction to Hydrofluoric Acid (HF) Uses Properties Health Hazards Good Work Practices  HF Storage and Compatibility   Equipment Personal Protective Equipment (PPE) Spills/First Aid Brown University Environmental Health and Safety 401.863.3353

Introduction

     Hydrofluoric acid is a strong, inorganic acid with special chemical properties that make it particularly hazardous to laboratory researchers. Highly corrosive Very reactive Incompatible with many materials Exposure to HF can result in burns and even death Brown University Environmental Health and Safety 401.863.3353

Introduction

 Synthesis of HF CaF 2 + H 2 SO 4 2HF + CaSO 4 (Fluorospar) (Gypsum)  HF is then isolated by distillation.

Brown University Environmental Health and Safety 401.863.3353

Uses of HF

Fluorocarbon Production Aluminum Production Refinery Alkylation Glass Etching Purification of Quartz Purification of Uranium Rare Metal Processing Drug & Dye Production Semiconductor Etching Laboratory Experimentation Brown University Environmental Health and Safety 401.863.3353

Mineral Identification Fertilizer Production Tanning Leather Metal Cleaning Metal Pickling Insecticide Production Propellants & Solvents Fabric Rust Stain Removal

Properties of HF

   Clear, colorless, noncombustible, highly corrosive liquid Highly reactive with the following  Glass  Ceramics    Concrete Rubber Metals Although noncombustible, in reacting with metals can produce H 2 which is extremely flammable Brown University Environmental Health and Safety 401.863.3353

Properties of HF

Anhydrous HF 70% HF 49% HF

Produces dense vapor Produces dense vapor Normally nonfuming Sharp, pungent odor Sharp, pungent odor Boiling Point: 19.5

°C 66 °C Irritating odor 106 °C Least corrosive to metals More corrosive to metals than anhydrous HF Most corrosive to metals Brown University Environmental Health and Safety 401.863.3353

Health Hazards

There are two main concerns when it comes to exposure to hydrofluoric acid  HF is extremely corrosive to body tissues.

 HF is extremely toxic when it enters the body.

Brown University Environmental Health and Safety 401.863.3353

Health Hazards Cont.

 Corrosivity  Greater than 50% HF  Immediate, severe, deep-seated, slow-healing burns  Deep tissue layer destruction  20-50% HF  Onset of pain may take up to eight hours  0-20% HF  Onset of pain may take up to 24 hours Hydrofluoric acid burns to finger tips Brown University Environmental Health and Safety 401.863.3353

Severe thigh burn after exposure to HF

Health Hazards Cont.

 Toxicity  The fluoride ions readily penetrate tissues and can rapidly reach toxic levels.

 Fluoride ions bind calcium in body tissue. This can result in several conditions:  abnormal mineral storage/utilization     enzyme inhibition blood clotting defects metabolic pathway interruption abnormal function  hypocalcemia Brown University Environmental Health and Safety 401.863.3353

Brown University Environmental Health and Safety 401.863.3353

Health Hazards Cont.

 The extent of the exposure is a factor of the concentration, the duration and the surface area affected.

 10 mL of 70% HF is enough to bind all of the calcium ions in the bloodstream!

 Any inhalation or ingestion is of a concern.

So, how can you prevent an HF exposure?

Brown University Environmental Health and Safety 401.863.3353

Good Work Practices

 HF Storage and Compatibility  HF should always be stored in polyethylene or Teflon containers (this includes secondary containers and waste as well).

 HF should be separated from alkalis, metals, oxidizers, cyanides, reducing materials and sulfides. Brown University Environmental Health and Safety 401.863.3353

Good Work Practices

 Equipment Requirements  Always work with HF in a fume hood.

 Know the location of the nearest eyewash and emergency shower. Brown University Environmental Health and Safety 401.863.3353

Good Work Practices

 Equipment Requirements Cont.  Have calcium gluconate gel available in the event of an exposure (be sure to check the expiration date before use).  Be sure to wear the appropriate personal protective equipment (PPE).

Brown University Environmental Health and Safety 401.863.3353

Good Work Practices

 Appropriate PPE for HF Handling   Splash goggles Heavy duty nitrile over disposable nitrile  Lab coat  Face shield (if pouring)  MSDS should be in work area. Brown University Environmental Health and Safety 401.863.3353

Spills

 In the event of a spill, notify those in the area and leave immediately, closing the door behind you.

 Call Public Safety at 863-4111 to notify them of a hydro

fluoric

acid spill.  Ensure the Public Safety understands that it is a hydrofluoric and not a hydrochloric acid spill.

 Do not attempt to clean up the spill yourself, regardless of the amount. Brown University Environmental Health and Safety 401.863.3353

First Aid

  Using a gloved hand, apply calcium gluconate gel to the exposed area.

 In the event that you are exposed to HF, flush the affected area with water for five minutes.

Notify your supervisor and seek medical attention immediately.  Provide Emergency Medical Services and/or the doctor with the MSDS. Brown University Environmental Health and Safety 401.863.3353

First Aid

 Within 48 hours after seeking medical attention, fill out the Laboratory Accident Report form and the Injury Report form.

 Return or fax the Laboratory Accident Report form to EHS (863-7676).

 Return or fax the Injury Report form to Insurance and Risk (863-1566). Both forms can be found at http://www.brown.edu/Administration/EHS/lab/index.htm

Brown University Environmental Health and Safety 401.863.3353

Summary

    Know the hazards of working with HF.

Take the proper precautions when working with HF.

Treat any exposure to HF very seriously.

Contact the Chemical Hygiene Officer (863-1737) or the Laboratory Safety Specialist (863-7697) with any additional questions.

Brown University Environmental Health and Safety 401.863.3353