Toxicity fluorocarbons

In the absence of air, TEE disproportionates violently to give carbon and carbon tetrafluoride the same amount of energy is generated as in black powder explosions. This type of decomposition is initiated thermally and equipment hot spots must be avoided. The flammability limits of TEE are 14—43% it bums when mixed with air and forms explosive mixtures with air and oxygen. It can be stored in steel cylinders under controlled conditions inhibited with a suitable stabilizer. The oxygen content of the vapor phase should not exceed 10 ppm. Although TEE is nontoxic, it may be contaminated by highly toxic fluorocarbon compounds. 

Health and Safety Factors. Fluorocarbons containing bromine or iodine are more toxic than the corresponding chloro compounds. When the ratio of the fluorine to other halogens is high, the toxicity can be quite low, especially for bromofluorocarbons. Perfluoro-l-bromooctane [423-55-2] has an LD q of greater than 64 mL/kg when adininistered into the gastrointestinal tract, and has Htde effect when instilled into the lungs (49). Other examples are included in Table 7. 

In general, under normal handling conditions, the fluorocarbon elastomers have been found to be low in toxicity and irritation potential. Specific toxicological, health, and safe handling procedures are provided by the manufacturer of each fluorocarbon elastomer product upon request. 

Polytetrafluoroethylene decomposition products thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products containing carbon, fluorine and oxygen. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentration should be minimal. (Trade names Algoflon, Fluon, Teflon, Tetran.)... 

In contrast to the toxicity of these fluorinated oxygen and nitrogen-containing compounds, the products from trifluorinated methyl ketones and amines are reported to have low acute toxicities 62). The fluorocarbons are insoluble in water, alcohol, and hydrocarbons 38). 

Finally, it may be noted that the fluorocarbons (CJFj,), which have great stability, are in general non-toxic. 

The lower members, e.g. CF4 and C2F6, are colourless, odourless gases of very low toxicity. By comparison with the fluoro-acetates they may be said in general to be non-toxic. This is understandable, particularly with regard to the simple saturated fluorocarbons, as they do not contain the FCH2CO group and are not likely to give rise to it in the animal body. Recently,... 

Fagan DG, Forrest JB, Enhoming G, et al. 1977. Acute pulmonary toxicity of a commercial fluorocarbon-lipid aerosol. Histopathology 1 209-223. 

Sakata M, Kazama H, Miki A, et al Acute toxicity of Fluorocarbon-22 Toxic symptoms, lethal concentration and its fate in rabbit and mouse. Toxicol Appl Pharmacol 59 64-70, 1981... 

Trochimowicz HJ et al Ninety-day inhalation toxicity studies on two fluorocarbons. Toxicol Appl Pharmacol 41 299 (abst), 1977... 

Clayton JW Jr The toxicity of fluorocarbons with special reference to chemical constitution. J Occup Med 4 262-273, 1962... 

Trochimowicz HJ, Rusch GM, Chiu T, et al Chronic inhalation toxicity/carcinogenicity study in rats exposed to fluorocarbon 113 (FC-113). Fundam Appl Toxicol 11 68-75, 1988... 

Nonfluorine CFC substitutes have been considered, but few are fully satisfactory. For example, we could go back 50 years to the use of anhydrous ammonia as a refrigerant, but NH3 is as toxic now as it ever was. Cyclopentane could be used as a foam-blowing agent, but it is less effective than HCFC-141b and besides would contribute to the volatile organic compound load in the troposphere, which is the root cause of ozone pollution (Section 8.3.2). On the other hand, supercritical CO2 is emerging as an alternative to CFCs in various steps in the preparation of fluorocarbon polymers (Section 8.1.3). 

Several authors have attempted to constitute rules for rating the toxicity of fluorocarbons with reference to their chemical constitution and to predict the risk for human beings.21,22 However, no general reliable conclusions can be drawn. 

Table 12. Toxicities of Various Hydro-/Ch1oro-/Fluorocarbons... 

Fluorinated polymers are by nature inert and nontoxic materials. A certain toxicity may however be incorporated from additives added, e.g. perfluorooctanoic acid or traces of monomers. In addition, toxic organo-fluorine compounds may be generated from these polymers by high temperature decomposition.6-64- 16-118 Biological effects of fluorocarbon fibers have been described.119 Toxicities of polychlorotrifluoroethylenc oils (hydraulic fluids) have also been discussed.202... 

Alternative Fluorocarbon Acceptability Study (AFEAS) and Alternative Fluorocarbon Toxicity Testing (PA FT), Program Administrator, The West Tower, Suite 400,1333 H Street N.W., Washington, DC 20005, U.S.A. 

Chemical Hazards. Chemical manufacturers and employees contend with various hazards inherent in production of even commonplace materials. For example, some catalysts used in the manufacture of polyethylene (see Olefin polymers) ignite when exposed to air or explode if allowed to become too warm the basic ingredient in fluorocarbon polymers, eg, Teflon (see Fluorine compounds, organic), can become violendy self-reactive if overheated or contaminated with caustic substances (45,46) one of the raw materials for the manufacture of acrylic fibers (see Fibers, acrylic) is the highly toxic hydrogen cyanide (see Cyanides). 

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