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Teflon resins are available m two types the TFE resin (tetrafluoroethylene poly mer) and the FEP resin (fluonnated ethy lene-propylene polymer) Both are physio logically inert The products of pyrolysis of Teflon below 392 F (200 C) are nonhazardous, but above this temperature, several fluorocarbon gases, hydrogen fluoride, and a sublimate are formed These do not appear to be toxicologically significant until about 482 F (250 C) At 716 F (380 C), small amounts of toxic gases, which have caused death bv pulmon ary edema in experimental animals, are evolved The only known difficulty in hu man exposure has occurred when Teflon res ins are processed at 644-725 F (340-380 C) At these temperatures, a condition somewhat like metal fume fever is exhibited, but re covery is rapid, usually in 48 hours or less All operations that can lead to the pyrolysis of Teflon resins should therefore be pro hibited, particularly smoking where the to bacco may be contaminated with Teflon dusts See Hygienic Guide Tellurium is found as a trace element in various minerals and is used in small amounts in a number of industries, especially the glass industry It increases the machinability of some metals and improves the tough ness of rubber hose and cable and the hard ness of lead In man, the absorption of even a very small amount of tellurium m any form is immedi ately followed by the production of a garlicky 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 selemde, destroys the red corpuscles It is believed to be more toxic than either, but is not so often encoun tered 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 percent age of the men showed the garlic odor of the breath and sweat and also complained of dryness of the mouth and a metallic taste Men with the highest exposures, who also had the highest rate of tellurium excretion. showed drowsiness starting in the early after noon and later becoming more severe Com plaints of loss of appetite and nausea at these relatively low exposures were less common See Hygienic Guide TEPP (tetraethyl pyrophosphate) is the active ingredient in an insecticide mixture that goes by the same name Since the esti mated fatal dose for a human being is ap proximately 600 mg taken orally, it is m the class of highly toxic materials 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 in the chest should be removed immediately from the exposure 1.1.2.2- Tetrabromoethane (acetylene tetrabromide) is a high-boiling, heavy, yellow ish liquid used as an indicator liquid in gauges and for separating minerals by density Its low vapor pressure at room temperature makes it safer to handle than might be ex pected The LDjo for rabbits and guinea pigs is about 0 4 gm per kg of body weight Exposure to the vapor causes respiratory irritation 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 m its properties to trichloroethylene except that its boiling point is slightly above that of water so that boiling degreasers containing it automatically keep themselves dry without loss of solvent Its most important toxic effect is depression of the central nervous system In experi mental exposures of human subjects, those exposed to concentrations greater than 200 ppm promptly suffered central nervous sys tem symptoms, while those exposed to about 100 ppm did not See Hygienic Guide Tetraethyl lead--see Lead Also see Hygenic Guide 1375