Document ExOpEEzLL0x25a4xwQJ9DBrGN

38--Industrial Toxicology tinent or from the United States, although in both areas there have been several exten sive investigations of this question Teflon resms are available m two types the TFE resm (tetrafluoroethylene polymer) and the FEP resm (fluonnated ethylenepropylene polymer) Both are physiologically inert The products of pyrolysis of Teflon below 392 F are nonhazardous, but above this temperature, several fluorocarbon gases, hy drogen fluonde, and a sublimate are formed These do not appear to be toxicologically sig nificant until about 482 F At 716 F, small amounts of toxic gases, which have caused death by pulmonary edema in experimental animals, are evolved The only known difficulty in human exposure has occurred when Teflon resins are processed at 644-725 F At these temperatures, a condi tion somewhat like metal fume fever is ex hibited, but recovery is rapid, usually m 48 hours or less All operations that can lead to the pyrolysis of Teflon resins should therefore be prohibited, particularly smoking where the tobacco may be contaminated with Teflon dusts Tellurium is found as a trace element in various minerals and is used m small amounts m a number of industries, especially the glass industry It increases the machinabihty of some metals and improves the toughness of rubber hose and cable and the hardness of lead In man, the absorption of even a very small amount of tellurium m any form is imme diately followed by the production of a gar licky odor in the breath and the sweat, due to the elimination of minute amounts of tellurium as methyl tellunde This elimination is likely to continue for weeks or months Hydrogen tellunde, a poison gas similar to arsine and hydrogen selenide, destroys the red corpuscles It is believed to be more toxic than either, but is not so often encountered in industry In an investigation of workmen in a foundry who had been exposed to 0 1 to 10 mg of tellunum per 10 cu m of air, a large per centage of the men showed the garlic odor of the breath and sweat and also complained of dryness of the mouth and a metallic taste 1172 Men with the highest exposures, who also had the highest rate of tellunum excretion, showed drowsiness starting in the early afternoon and later becoming more severe Complaints of appetite loss and nausea at these relatively low exposures were less common TEPP (tetraethyl pyrophosphate) is the ac tive ingredient in an insecticide mixture that goes by the same name Since the estimated fatal dose for a human being is approximately 600 mg taken orally, it is in the class of highly toxic matenals In its use, toxic dust respirators or supplied air respirators and protective clothing which will completely prevent skin contact should be worn Anyone with a severe headache or a feeling of tightness or constriction m the chest should leave or be removed immediately 1.1.2.2- Tetrabromoethane (acetylene tetrabromide) is a high-boiling, heavy, yellowish liquid used as an indicator liquid in gages and for separating minerals by density Its low vapor pressure at room temperature makes it safer to handle than might be ex pected The LDm for rabbits and guinea pigs is about 0 4 gm per kg of body weight Ex posure to the vapor causes respiratory irrita tion and damage of the liver appearing a few days after a single acute exposure 1.1.2.2- Tetrachloroethane (acetylene tet rachloride) is an excellent solvent for a num ber of paints and lacquers It is also a very dangerous compound since inhalation of it at a concentration that is barely perceptible by odor can lead to extensive liver damage Tetrachloroethylene (perchloroethylene) is a chlorinated solvent used primarily for de greasing It is Similar in its properties to trichloroethylene except that its boiling point is slightly above that of water so that boiling degreasers containing it automaticallv keep themselves dry without loss of solvent Its most important toxic effect is depression of the central nervous system In experimen tal exposures of human subjects, those exposed to concentrations greater than 200 ppm promptly suffered central nervous system symptoms, while those exposed to about 100 ppm did not