Hydrofluoric acid tissue destruction

Hydrofluoric acid is highly corrosive to skin and mucous membranes. Even in fairly low concentrations, it causes painful skin burns and severe damage to eyes and the respiratory system. Exposure at higher levels results in destruction of tissues and death. No one in l e.xas City was exposed to more than trace concentrations of hydrofluoric acid. The acid vessel had a capacity of about 850 barrels of which a small fraction was released. 

HF solutions in contact with skin result in marked tissue destruction undissociated FIF readily penetrates skin and deep tissue, where the corrosive fluoride ion can cause necrosis of soft tissues and decalcification of bone the destruction produced is excruciatingly painful.Fluoride ion also attacks enzymes (e.g., of glycolysis) and cell membranes. The process of tissue destruction and neutralization of the hydrofluoric acid is prolonged for days, unlike other acids, which are rapidly neutral-ized. ° Because of the insidious manner of penetration, a relatively mild or minor exposure can cause a serious burn. When skin contact is with solutions of less than 20%, the burn manifests itself by pain and erythema with a... 

The pulmonary toxicity of uranium compounds varies in animals. Reports of pulmonary toxicity in animals after acute-duration exposure to uranium are limited to experiments with uranium hexafluoride. Gasping and severe irritation to the nasal passages were reported after 10 minute exposures at 637 mg U/mg in rats and mice (Spiegl 1949) and nasal hemorrhage in rats after a 5 minute exposure to 54,503 mg/m (Leach et al. 1984). Uranium hexafluoride promptly hydrolyzes on contact with water to uranyl fluoride and hydrofluoric acid. Thus, the animals were potentially exposed to hydrofluoric acid, a potent toxicant to respiratory tract epithelium, which probably contributed to pulmonary tissue destruction (Leach et al. 1984 Spiegl 1949 Stokinger et al. 1953). In addition, exposure to fluoride ions can result in hypocalcemia, hypomagnesemia, pulmonary edema, metabolic acidosis, ventricular arrhythmia, and death (Meditext 1998). 

Toxicity Boron trifluoride (and organic complexes such as Bp3-etherate) are extremely corrosive substances that are destructive to all tissues of the body. Upon contact with moisture in the skin and other tissues, these compounds react to form hydrofluoric acid and fluoroboiic acid, which cause severe burns. Boron trifluoride gas is extremely irritating to the skin, eyes, and mucous membranes. Inhalation of boron trifluoride can cause severe irritation and burning of the respiratory tract, difficulty breathing, and possibly respiratory failure and death. Exposure of the eyes to BF3 can cause severe burns and blindness. This compound is not considered to have adequate warning properties. Boron trifluoride has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans. Chronic exposure to boron trifluoride gas can cause respiratory irritation and damage. 

Weak acids often have a toxic counterion, while few H are released and, consequently, the corrosive damage remains limited. This is particularly the case with hydrofluoric acid whose pK expresses low dissociation (pK=3.2). The importance of skin lesions is related to the association of a superficial destruction of the skin barrier by H+ allowing the fluoride ions (F ) to penetrate tissues and express their severe cytotoxicity (see Sect. 4.1.2.1). 

Another problem unique to hydrofluoric acid bums is delayed symptoms. Concentrations less than 20 percent may not produce symptoms for 24 hours. Symptoms of exposure to concentrations between 20 percent and 50 percent may be delayed for 1 to 8 hours. Concentrations above 50 percent produce immediate burning, pain, and tissue destruction. 

Skin corrosive Causes severe skin burns and eye damage lA, IB, 1C Danger Produces destruction of skin tissue -visible necrosis of epidermis and dermis Sodium hydroxide, potassium hydroxide, sulfuric acid, hydrofluoric acid, nitric acid... 

As with most acids, the initial extent of the burn depends on concentration and duration of contact. Unlike other acids, hydrofluoric acid penetrates the skin, causing destruction of deep tissue layers including bone. This process may continue for days. 

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