Document mbJqJDpej7dVLyk54XEN1kmq4

1317 b Approximate milligrams of particulate per cubic meter of air * As sampled by method that does not collect vapors h According to analytically determined com* position 1 For control of general room air, biologic monitoung is essential for personnel control * 1968 Revision 1968 Addition Substance 4 Asbestos 12 fibers/mt > 5/i in length1' , or 2 mppef*' * Cnstobalite Use one-halt the value calcu lated from the count or mass formulae for quartz * Quartz (1) TLV for respirable dust in mg/rrr* 10 mg/cu mm Per cent Respirable Quartz + 2 (2) Total dust respirable and non respirable 30 mg/cu m Per cent Quartz + 2 * Tridymite Use one-half the value calcu lated from formulae for quartz 1 As determined b> the membrane filter method at 430 g-phase contrast magnification k As counted b> the standard nnpinger, light field count technique " Both concentration and per cent quartz for the application of this limit are to be determined from the fraction passing a si7e-sdcctor with the following characteristics Aerodynamic Diameter-/* (unit density sphere) *2 25 35 $0 10 Per cent passing selector 90 75 50 25 0 * 1968 Revision Appendix A A' Benzidine Because of high incidence of bladder tumors in man, any exposure, including skin, is extremely hazardous A3 /3-Naphthylamine Because of the ex tremely high incidence of bladder tu mors in workers handling this compound and the inability to control exposures 0-naphthylamine has been prohibited by the State of Pennsylvania from manu facture, use and other activities that in volve human contact A9 N-Nitrosodimethylamine Because of extremely high toxicity and presumed carcinogenic potential ofthiscompound, contact by any route should not be per mitted A* Polytetrafluoroethylene decomposi tion products Thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products con taining carbon, fluorine and oxygen Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluonde to provide an index of exposure No TLV is lecommended pending determination of the toxicity of the products, hut air concentrations should he minimal A9 fi Propiolactone Because of high acute toxicity and demonstrated skin tumor production in animals, contact by any route should be avoided A Gasoline and/or Petroleum Distillates The composition of these materials varies greatly and thus a single TLV for all types of these materials is no longer applicable In general, the aromatic hydrocarbon content will determine what TLV applies Consequently the content of benzene, othei aromatics and additives should be determined to airive at the appropriate TLV (Elkins, etal A I HAJ 24,99,1963) * trade Names Algoflon, Fluon. Halon Teflon, 1 etran Appendix B B 1 THRESHOLD LIMIT VALUES FOR MIXTURES .When two nr more hazardous substances are present, their combined effect, rather than that of either individually, should be given pnmaiy consideration In the ab sence of inlonnation to the contrary, the effects ol the different hazards should he considered as additive That is, if the sum ol the following fractions, C| C* T +T`+ Cn Tn exceeds unity, then the threshold limit of the mixture should be considered as being exceeded C, indicates the observed atmos pheric concentration, and T, the corre sponding threshold limit, (See Example 3A a) Exceptions to the above rule may be