HYDROFLUORIC ACID (HF)

SYNONYMS
Fluoric acid.
GENERAL PRECAUTIONS
Very hazardous substance, handle with extreme care. Use a fume hood.
Wear protective clothing at all times.
Avoid skin and eye contact.
Avoid inhalation.
CHARACTERISTICS
Clear, colourless liquid with a highly corrosive, irritating, white vapour.
HEALTH HAZARD DATA
A liquid which gives off acrid fumes. Both the liquid and the vapour are extremely corrosive and toxic. Exposure to high concentrations can be fatal. Injuries from dilute acid and vapour may not become apparent for several hours. Concentrations of 10ppm are intolerable to breath. 25ppm can produce severe injuries with 50ppm causing death. Acute eye exposure is severely irritating, a splash causing severe burns with blindness resulting if treatment is not rapid. Skin contact causes severe burns and it is rapidly absorbed through the skin. Pain may not be immediate with dilute solutions. Inhalation is extremely irritating to the respiratory tract and high exposure can be fatal. Ingestion causes severe irritation and burning with damage to the mouth, oesophagus and stomach.
TREATMENTS Skin ­ immediately drench with large amounts of water, do not wait to remove clothing but remove under the safety shower. Wash until all evidence of the chemical has been removed (approximately 15 minutes). Massage calcium gluconate gel into affected parts until pain subsides, then seek immediate medical attention. Calcium gluconate is available from any pharmaceutical outlet and should be part of your laboratory first aid kit if hydrofluoric acid is handled in your laboratory.
Eyes ­ immediately wash the affected eye with large amounts of water until all evidence of the chemical has been removed, then apply calcium gluconate eye drops. Seek immediate medical attention. Calcium gluconate eye drops are available from any pharmaceutical outlet and should be part of your laboratory first aid kit if hydrofluoric acid is handled in your laboratory.
Inhalation ­ remove from the area of exposure to fresh air. If breathing has ceased apply artificial respiration. If breathing is laboured give oxygen. Seek immediate medical attention.
Ingestion ­ wash the mouth with water and give milk and give milk of magnesia or milk to drink. Do not induce vomiting. Seek immediate medical attention.
INCOMPATIBILITY
Hydrofluoric acid is incompatible with all materials containing silica and will react vigorously with neutralising agents. Heating produces toxic fumes of fluorine.
STORAGE
Store in a cool, dry, well ventilated area that is secure.
HANDLING
Use a fume hood that will keep levels of exposure below the recommended threshold, ie. 3ppm. If exposure is expected to exceed this level then a respiratory is recommended. Concentrations above 10ppm are intolerable to breath, a self­contained breathing apparatus is recommended. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves (PVC), a full face shield plus safety goggles and a face mask as a minimum standard. In addition a PVC apron, leggings and boots will provide added protection.
DISPOSAL
WEAR:
Rubber gloves, laboratory coat and self contained breathing apparatus. have a body shield available.
SPILLS:
Cover the contaminated surface with sodium bicarbonate or soda ash-slaked lime mixture (50/50). Mix, and add water if necessary to form a slurry. scoop up the slurry and discharge to the sewer with a large excess of water.. wash the spill site with a soda ash solution.
PACKAGE LOTS:
Add slowly to a large volume of an agitated solution of soda ash and slaked lime until the solution is neutral. Discharge to the sewer with a large excess of water.
ENVIRONMENT:

BACK to the top of the Glossary Contents List
BACK to the top of the Chemical Contents List

REFERENCES