Hydrofluoric acid is one of the most dangerous Acid Injuries of acids to come in contact with. In an aqueous solution, it is a colorless and fuming liquid with a strong and irritating smell. It is highly corrosive and usually comes in concentrations of 46 percent and 53 percent. It can be diluted to much less concentrated solutions or concentrated to above 70 percent.
The most unique property of hydrofluoric acid or HF is that it attacks glass, etching it. It can dissolve stone and silica so it must be kept in wax, lead, or plastic bottles. It has an extremely caustic effect on any kind of organic tissue. The industrial uses of HF include frosting, etching and polishing glass, removing sand from castings made of metal and for etching silicon wafers in industrial processes, such as the manufacturing of semiconductors.
When one sustains burns to either the eye or the skin from high strength hydrofluoric acid, the burns are extremely painful and severe. Eye burns happen with splashes when the acid is used in industry or a laboratory. Gloves with holes in them or a spill can result in severe skin burns. Burns to the face can happen with splash-like injuries. The burns are more severe if the acid is highly concentrated and if the length of exposure is long. Workers have to avoid inhaling its vapors, because exposure to the airways can be devastating.
Contact with the skin is particularly corrosive. There is marked tissue destruction as the HF ions penetrate the skin. They soon reach the deep tissues of the soft tissue, resulting in tenosynovitis, tendinitis, and decalcification of bone. Destruction of bone is particularly painful and it takes a long time to neutralize this acid, once it has penetrated the skin. Doctors say that even mild exposure to HF can cause a serious burn. If the burn is from HF at concentrations of less than 20 percent, there is pain and redness that doesn’t show up for about twenty-four hours. The burns are often made worse because there is an automatic delay in washing of the wound or proper irrigation.
If the injury is due to HF burns of 20-50 percent, the pain and redness takes about 1-8 hours to show up. If the concentration of HF is fifty percent or more, the symptoms and tissue destruction shows up immediately. The different symptoms include only erythema, central blanching along with peripheral erythema, ulceration, blue-gray discoloration and necrosis of tissue.
The possibility of excess fluorine in the system, called fluorosis, can happen with bigger burns as well. Eye contact can happen with vapor transmission of HF through the fumes or from splash injuries. It can result in loss of sight that is permanent or sometimes temporary. Historically speaking, the treatment of these burns has been to apply a paste of magnesium oxide but this isn’t used much today. Now Benzalkonium chloride solution is used for the management of hydrofluoric burns. It is also used as an iced solution to decrease the lymphatic spread of HF.