Hydrogen fluoride exposure

Because the medical treatment of hydrogen fluoride exposure is so specialized and differs from that of other mineral acids exposures, not all physicians may be aware of appropriate... 

Speed in removing the victim from the contaminated atmosphere or removing the vapor or liquid from the skin or eyes is essential. First aid must start immediately in all cases of contact with the particular gas in any form. All affected persons should be referred to a physician, no matter how slight the injury, and the physician should be given a detailed account of the accident As soon as possible, more thorough medical treatment should be administered by a physician, preferably one familiar with hydrogen fluoride exposure treatment [3]. 

Hydrogen fluoride or compounds that can produce it and fluorine-containing oxidizers should be handled with adequate safety equipment and extreme care by weU-trained personnel. Often the effect of skin exposure is not immediately evident, especially when dilute solutions are handled. Pain may develop several hours later. 

Germanium tetrafluoride produces hydrogen fluoride in aqueous acidic solutions. Hydrogen fluoride is toxic and very corrosive. The OSHA permissible exposure limit (17) and the American Conference of Governmental Industrial Hygienists (ACGIH) TLV for fluoride is 2.5 mg/m of air (18). 

Because PTFE resins decompose slowly, they may be heated to a high temperature. The toxicity of the pyrolysis products warrants care where exposure of personnel is likely to occur (120). Above 230°C decomposition rates become measurable (0.0001% per hour). Small amounts of toxic perfiuoroisobutylene have been isolated at 400°C and above free fluorine has never been found. Above 690°C the decomposition products bum but do not support combustion if the heat is removed. Combustion products consist primarily of carbon dioxide, carbon tetrafluoride, and small quantities of toxic and corrosive hydrogen fluoride. The PTFE resins are nonflammable and do not propagate flame. 

The third category for interactions is high dose (III). The effects produced by this level of interaction can be seen by the casual observer. The result of high-dose exposure is destruction or severe injury of the forest system. High-dose conditions are almost always associated with point source emissions. The pollutants most often involved are SO2 and hydrogen fluoride. Historically, the most harmful sources of pollution for surrounding forest ecosystems have been smelters and aluminum reduction plants. 

TABLE 8.5.2 Chapter 8 Exposure Limits for Hydrogen Fluoride... 

TABLE 8.5.3 Predicted Effects on Human Health of Exposure to Various Concentrations of Hydrogen Fluoride ... 

A Caution Hydrogen fluoride and fluorine are dangerous materials. Exposure to them will cause severe, painful, and perhaps fatal injury. Exposure may not be evident for several hours. The procedures described here pose the risk of exposure to hydrogen fluoride and to elemental fluorine and should only be carried out by, or under the direct supervision of, qualified professionals. Qualified first aid treatment and professional medical resources must be established prior to working in the area. Prompt treatment is necessary to reduce the severity of damage from exposure and should be sought immediately following exposure or suspected exposure. Material safety data sheets are available from HF and fluorine suppliers. Their recommendations should be followed scrupulously. 

May cause severe and painful irritation of the eyes, nose, throat, and lungs. Severe exposure can cause accumulation of fluid in the lungs (pulmonary edema). Inhalation toxicity similar to hydrogen chloride and hydrogen fluoride. May cause second or third degree burns upon short contact with skin surfaces. Oral ingestion may result in tissue destruction of the gastrointestinal tract. Decreased blood cholinesterase levels have been reported in animals. 

Human toxicity values have not been established or have not been published. However, based on available information, the Compressed Gas Association has established an LC50 of 260 ppm with an exposure of 1 h, or approximately one-fifth as toxic as hydrogen fluoride. 

Eye exposure, to hydrogen fluoride, 14 18 Eye irritation, in spas/hot tubs, 26 197-198 Eyehners, 7 862 Eye makeup, 7 861-862 Eye shadows, 7 862 Eyewash fountains, 21 849 Eyewear, polycarbonate, 19 809 Eyring equation, 13 407 Eyring transfer matrix technique, 1 32 Ezetimibe (zetia), 5 143—144... 

Ingot casting, 23 266 Ingot production, titanium, 24 857 Inhalation. See also Dust inhalation hydrogen fluoride, 14 17-18 influence on toxicity, 25 211 of PVC dust, 25 676-677 of sodium tetrasulfide, 22 875 studies of, 25 227t of sulfuric acid, 23 794 of toluene, 25 179t of VDC, 25 692-694 Inhalation anesthetics, 11 867-868 Inhalation exposure... 

Repeated exposure to excessive concentrations of hydrogen fluoride over a period of years may result in an increased radiographic density of bone and eventually may cause crippling fluorosis (osteosclerosis due to deposition of fluoride in bone)/ The early signs of increased bone density from fluoride deposition are most apparent in the lumbar spine and pelvis and can be detected by X ray. 

Halton DM et al Toxicity Levels to Humans During Acute Exposure to Hydrogen Fluoride, p 40. Ottawa, Canada, Atomic Energy Control Board, November 28, 1984... 

National Institute for Occupational Safety and Health Criteria for a Recommended Standard.. . Occupational Exposure to Hydrogen Fluoride. DHEW (NIOSH) Pub No 76-143, pp 106-115. Washington, DC, US Government Printing Office, 1976... 

Apparent photosynthetic rates in plants subjected to SO2 or NO exposures with constant pollutant concentrations, as illustrated in Figure 1, characteristically dropped rapidly upon initiation of treatment to new depressed equilibrium levels which could be maintained for several ho irs. Hydrogen fluoride, conversely, caused CO2 uptake rates to decline more gradually during fumigation. Chlorine, O3 and NO2 exposures induced inhibition rate responses which were intermediate between these... 

Conversely, exposure to hydrogen fluoride at 0 °C over short periods of time leads to almost quantitative hydrolysis.[37-39] In aprotic organic solvents, decomposition takes place unless the sulfate hemi-ester is neutralized with strong counterions.[37,381 The results of a detailed study are summarized in Figures 1 and 2t4°l which show the effect of various acids used in peptide chemistry in deprotection and in cleavage from the resin as well as the effect of temperature on the hydrolysis of tyrosine 0-sulfate as a sodium salt. 

Acute symptoms of hydrogen fluoride inhalation may include coughing, choking, chest tightness, fever, chills and cyanosis. Exposure to hydrogen fluoride vapor can result in pul-... 

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