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Hydrofluoric Acid. Brown University Environmental Health & Safety. 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. Introduction.
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Hydrofluoric Acid Brown University Environmental Health & Safety
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
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
Introduction • Synthesis of HF CaF2 + H2SO4 2HF + CaSO4 (Fluorospar) (Gypsum) • HF is then isolated by distillation. 250 °C
Fluorocarbon Production Aluminum Production Refinery Alkylation Glass Etching Purification of Quartz Purification of Uranium Rare Metal Processing Drug & Dye Production Semiconductor Etching Laboratory Experimentation Mineral Identification Fertilizer Production Tanning Leather Metal Cleaning Metal Pickling Insecticide Production Propellants & Solvents Fabric Rust Stain Removal Uses of HF
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 H2 which is extremely flammable
Health Hazards There are two main concerns when it comes to exposure to hydrofluoric acid- • HF is extremely toxic when it enters the body. • HF is extremely corrosive to body tissues.
Health HazardsCont. • 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 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
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?
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.
Good Work Practices • Equipment Requirements • Always work with HF in a fume hood. • Know the location of the nearest eyewash and emergency shower.
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).
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.
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 hydrofluoric 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.
First Aid • In the event that you are exposed to HF, flush the affected area with water for five minutes. • Using a gloved hand, apply calcium gluconate gel to the exposed area. • Notify your supervisor and seek medical attention immediately. • Provide Emergency Medical Services and/or the doctor with the MSDS.
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
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.