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i Threshold Limit Values For 1964 VJ t --*-? . . a ,0v Adopted ot the 26th Annuo! Meeting of ihe American Conference of Governmental Indus* trio! Hygienists, Philadelphia, Pennsylvcnio, April 25 - 28, 1964 6 }\ i Copyright 1954, by American Conference of Governmental Industrial Hygienists. The American Conference of Governmental Industrial Hygienists vrilt welcome requests for permission to republish or reprint these Threshold Limit Values. Requests for such permission should be directed to the Secretary-Treasurer, 1014 Broad way. Cincinnati 2, Ohio. Reprints may be purchased from the SecretaryTreasurer, 1014 Broadway, Cincinnati 2, Ohio. THRESHOLD LIMIT VALUES FOR 1964 Adopted ot the 2$:S Annuol '.'eefi.15 of the Amefiecn Conference of Governnecfol Hdusfrlot Hygienists Philodelphio, Po., April 25-23, 1964 The threshold limit values refer lo air-borne con centrations of substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed, day after day. without adverse effect. Because of wide variation in individual sus ceptibility, exposure of an occasional individual at ot even below the threshold limit may not prevent dis comfort, aggravation of a pre-existing condition, ot occupational illness. Threshold limits should be used as guides in Ihe control of health hazards and should not be regarded as fine lines between safe and dangerous concen trations. Exceptions are the substances given in Appendix A and certain of the substances given a "C" listing. The values not given a WC" listing re fer to time-weighted average concentrations for a normal workday. The amount by which these concen trations may be exceeded for short periods without injury to health depends upon a number of factors such as the natufe of the contaminant, whether very high concentrations even for short periods produce acute poisoning, whether the effects are cumulative, the frequency with which high concentrations occur, and the duration of such periods. AH must be taken into consideration in arriving at a decision as lo whether a hazardous situation exists. Enlightened industrial hygiene practice inclines toward controlling exposures below the limit rather than maintenance at the limit. Threshold limits are based on the best available information from industrial experience, from experi mental human and animal studies, and when possible, from a combination of the three. The basis on which the values are established may differ from substance to substance; protection against impairment of health V 'A; C m 1\ - *>st 4^ nay be the guiding factor for some, whereas reason able freedom from irritation, narcosis, nuisance of other forms of stress may dominate the Oasis for others. The Committee holds to the opinion that limits based on physical irritation should be considered no less binding than those based on physical impair ment; growing bodies of evidence indicate that physi cal irritation may promote and accelerate physical impairment. On what basis a limit is developed is giver, separately for each listed substance in "Docu mentation of Threshold Limit Values," a publication of the Threshold Limits Committee of the ACG1H. Ceiling vs Time-Weighted Average Limits. Al though the time-weighted average concentration pro vides the most satisfactory, practical way of moni toring air-borne agents for compliance with the limits, there are certain substances for which it is inap propriate. in the tatter group are substances which are predominantly fast acting and whose threshold limit is more appropiately based on this particular response. Substances with this hype of response are best controlled by a ceiling "C" limit that should not be exceeded. It is implicit in these definitions that the manner of sampling to determine compliance with the limits for each group must differ: a single grab sample, that is applicable to a "C" limit, is not appropriate to the time-weighted limit; here, a sufficient number of samples are needed to permit a time-weighted average concentration throughout a a complete cycle of operations or throughout the work shift. Whereas the ceiling limit places a definite bound ary which concentrations should not be permitted to exceed, the time-weighted average limit requires an explicit limit to the excorsions that are permissible above the listed value. The magnitude of these ex cursions may be pegged to the magnitude of the thres hold limit by an appropriate factor shown in Appendix C. It should be noted that the same factors are used by the Committee in making a judgment whether to include or exclude a substance tor a "C" listing. "Skin" Notation. Listed substances followed by the designation "Skin" refer to the potential con- 2 V ts'* -. . tribution to the over-ell exposure by the cutaneous route including mucous membranes and eye. This attention-calling cessation rs intended to suggest appropriate measures tor the prevention ol cutaneous absorption so th3t the threshold limit is not in* validated. Mixtures. Special consideration should be given also to the application of these values in assessing the health hazards which nay be associated with exposure to mixtures of two or more substances. A brief discussion of basic considerations involved in de- veloping threshold limit values lor mixtures, and methods tor their development, amplified by specific examples are given in Appendix B. "Inert" or Nuisance Particulates. A number of dusts or particulates that occur irt the working en- vironment ordinarily produce no specific effects upon prolonged inhalation. Some insoluble substances are classed as inert (e.g. iron and steel dusts, cement, bentonile, silicon carbide, titan.urn dioxide, cel- lulose): others may be soluble (starch, soluble oils, calcium carbonate' but are of such a tow order of activity lhal in concentrations ordinarily encountered do not cause physiologic impairment; still others may be rapidly eliminated or destroyed by the body (veg etable oils, glycerine, sucrose). In the case of the insoluble substances, there may be some accumula tion in the respiratory passages. In the case of the soluble substances, this accumulation will ordinar- ily be temporary but may interfere to some extent v/ith respiratory processes. Hence, it is desirable to control Ihe concentrations of such particulates in the air breathed by any individual, in keeping with good industrial hygiene practice. * A threshold limit of . or 50 mpocf, which ever is less, is recommended for substances in these categories and for which no specific threshold limits have-been assigned. This limit, for a normal work day, does not apply* to brief exposures at higher concentrations. Neither does it apply to those substances which may cause physiologic impairment at lower concentrations but for which a threshold limit has not yet been adopted. Physical Factors. It is recognized that such phy- sical factors as heat, ultraviolet and ionizing radia- `3 ' ; c * , f ~ l : ; : * * ; ; : 1 1 j r F | { > r.:n. humidity. abnormal pressure and the tike may added stress on the tody so that the effects f::-.?. exposure at a threshold limit may be altered.Vest cf these stresses act adversely to increase the toxic response of a substance. Although most threshold limits have built-in safety factors to guard against adverse effects of moderate deviations from normal environments, the safety factors of most substances are not of such a magnitude as to take zi`= of gross deviations. For example, continuous :.z;\ at temperatures above 9Q'F or over-time, ex tending the work-week more than SO5, might be considered gross deviations. In such instances judg ment must be exercised in the proper adjustments of the threshold limit values. 3 These limits are intended for use in the field of Industrial hygiene and should be interpreted and applied only by persons trained in this field. They re not intended for use. or for modification for use. 11) as a relative index cf toxicity, by making a ratio of tv.o limits, (2) in the evaluation or control of coimunity air pollution or air pollution nuisances. ri> in estimating the toxic potential of continuous uninterrupted exposures, (4) as proof or disproof of an A existing disease of physical condition, or (5) for carte blanche adoption by foreign countries. These values are reviewed annually by the Com mittee cn Threshold limits for revisions or additions, as further information becomes available. * notice of Intent*' At the beginning of each year, proposed actions of the Committee for the forth coming year are issued in the form of a "Notice o; Intent." This Notice provides not only an oppor tunity for comment, but solicits suggestions of sub stances to be'added to the list. The suggestions should be accompanied by substantiating evidence. 3 Legislative Action The Conference does not consider the Threshold Limit Values appropriate natter for adoption in legislative codes and regula tions, and recommends against such use. Reprint Permission. This publication may be re printed provided that written permission is obtained from the Secretary-Treasurer of the Conference and that it be published in its entirety. 4 ,Vv. RECOMMENDED values (In Alphobetical Order) SuSeionce ppm' Acetaldehyde.... . Acetic acid............ 200 10 Acetic anhydride........ 5 Acetone........-..... . Acetonitrile.......... 1.C00 40 Acetylene tetrabromtd 1 Acrolein............................ ............ 0.1 Acrylonitrile - Skin................. ..... 20 Aldrm (), 2. 3. 4, 10. 10- hexachloro-1, 4. 4a. 5, 8. 3 a-hexahydro-1, 4, 5, melhano-naphtrtaiene) Skin.... Allyl alconoi Skm Ally! chloride.......... Allyl filycidyj ether (ACF)....... Allyl propyl disulfide.................. Ammonia . Ammonium $ul(a.-n3ts {Animate),. 2 1 JO 2 50 Amyl acet3te..........._................... Amyl alcohol (isoamyi atcohol?. Aniline - Skin An.meny & compounds fas Sb: AnTU {alpha naphthyl ICO 100 5 thicureat... . Ajsentc & Compounds (as Ast .. AtSine........... ................--...........Barium {soluble compounds)...... O.OS C Benzene (benzol) - Skin.............. 25 Benz idine....................-- ......- Benzyl chloride.........--........... Beryllium ............. ----......... Boron oxide .......... ........................ 360 25 20 2 4C0 14 0 25 45 0.2S 3 45 J2 3S 15 525 360 19 0.5 0.3 O.S 0.2 o.r. eo ai S 0.002 15 &f vjpor of l 9tr >: 25 C r-4 7S0 mm H fi.eiv.irf ?:* of \t b/ ieoluni " ijp-rs.ton.T.j'.e mt.tiz'j'fti pi paM'CuijIt P` cub>t rmuef ter < * See Spsefeu s. 5 -'yi-.. ->cr? m *4* Sub>tact ppn** Mp/M*'* C 8oior> trifluoride.... -........-......... 1 Btomme........................................... 0.1 Butadiene {1 3-t>ut3diene)....... 1,.000 2 Butanon* (methyl ethyl ketone)....................................... 200 2-Butoxy ethanol (Butyl Ceilosolve) Skin.................... 50 Butyl acetate (n-butyl acetate).. 200 Butyl atcohol................................. 100 tert. Butyl alcohol...................... ICO C Eutylamine................................_... 5 C teit. Butyl chromate (as Cr03) - Skin......................................... - n- Butyl glycidyt ethef (BGE).... 50 Butyl metcaptan............................ 10 p-tett. Butyltoluene.................... 10 Cadmium oxide fume.................... Calcium aisenate.......................... - Camphoi......................................... - Carbon dioxide.............................. 5,000 Carbon disullide - Skin,.......... . 20 Carbon monoxide.......................... ICO Carbon tetrachloride Skin ........ 10 Chlordane (1, 2, 4, 5, 6, 7, 8, 8*octachloro*3a, 4, 7, 7a. tetrahydro-4, 7-methanoin- dane)........................................... Chlorinated camphene, 60^5..... - - Chlorinated diphenyl oxide....... - Chlorine......................................... 1 Chlorine dioxide............... -......... 0.1 C Chlorine trifluoride...................... 0.1 C Chloroacetaldehyde.................-- 1 Chlorobenzene (monochtorobenzene).......--........ *75 Chlorobromomethsne..... ............ . 200 Chtorodipheny! (42?o chlorine) - SkinChlotodiphenyl (54?e chlorine) - Skin-- C Chloroform (trichioromethane).... 50 1-ChlofO-l-nitropropane............. . 20 Chloiopicrin................................. . 0.1 Chloroprene (2-chloro-l, 3-butadiene)...... . 25 3 0.7 2,200 590 240 950 300 3C0 15 0.1 270 35 oQ O.l 1 2 9,000 0 110 6S 0.5 0.5 0.5 3 0.3 0.4 3 350 1,050 1 0.5 240 too 0.7 90 6 Subsrenc# ppm* Chromic acid and chromates (as Cr03).................................. - 0.1 Cobalt.... .........-......................... . - 0.5 Crag (R) herbicide [__sodium 2-.2,4- dichlorophenoxy) ethanol hydrogen sulfatej ................. - 15 Cresol (all isomers) - Skin......... 5 22 Cyanide (as CN) - Skin............... - 5 Cyclohexane.... ............. .............. . 400 1.400 Cyclohexanol................................ 50 200 Cyclohexanone....... ................... 50 200 Cyclohexene....... .......................... 400 1,350 2,4-D (2,4-dichlorophenoxy acelic acid).............................. DDT| 2,2-bis (p-chlorophenyl) - - jo . 1,1.1-Uichloroelhane_;- Son - 1 DDVP (0, 0-Dimethyl-?, 2-dic'n 5fO- vinyl phosphate).................... - 1 Oecabotane Skin.... ................... 0.05 0.3 Diacelone alcohol (4-hydioxy- 4-meihyI*2-pentanone)............ 50 240 Diborane..................................... . 0.1 0.1 1,2-Dibtomoelhane (ethylene dibromide)................................. 25 190 C o-Dichlorobenzene .................... . 50 300 p-Dichlorobenzene.... ................. . 7S 450 Dichlorodifluoromethane............ .1,000 4,950 1,1-Dichtoioelhane.................... . 100 400 1,2-Dichloroethane . (ethylene dichloride)............ . 50 200 1,2-Dichloroethylene_____ ___ . 200 790 C Oichloroethyl ether..................... - 15 90 Dichloromonofluoromethane..... .1,000 4,200 C 1,1-DiChIoro-l'niiroethane____ . 10 00 Dichloroletrafluoroethane......-- .1,000 7, COO Dieldrin 0,2,3,4,10,10-hexachloro *6,7-epoxy-l, 4, 4a, 5.6,7.3, octahydro-1,4, 5,8-dimethans - naphthalene) * Skin............... .. - 0.25 Oiethylamine....... _.................. .. 25 75 +1964 Addition or deletion of * e* t!964 Revision - see Tentative Value* l *: * ' =: : r ; : ' * ' tv-'? ;..T'vXV''J-"V . . : *a' ; rSJo 0% to-5 & ;voy y &S3 $wbtortC PPm* Difluotodibromomethane--.......... 100 C Digtycidyl ether (DGE)................ 0.5 Di isobutyl ketone......................... 50 Dimethyl acetamide * Skin.......... 10 Oimethylaniline (N-Klimethyl- aniline) * Skin.................. .......... 5 t Dimethylformamide - Skin....... - 1,1-Dimsthylhydrazine Skin -- 0.5 Dimethylsulfate - Skin.......... ...... 1 Dinitrobenzene - Skin................... - Dinitiotoijens Skin.-_________ -- OinitiO-O-cresol - Skin................ - Oioxane (diethylene dioxide)...... ICO Dipiopylene glycol methyl ether Skia................................ 100 End*in (1,2,3,4,10,10- hexa- chloro-S, 7-epoxy-l, 4,4a, 5,6. \8 ga-octahydro l,4-endo-5, 8-dimethanonaphthalene) - Skin . - EPM (O-ethyl O-p-nitrophenyi thionobenzenephosphonate) Skin - Ethyl acetate................. ........ ...... 400 Ethyl acrylate $kin...._............ .. 25 Ethyl alcohol (ethanol)........... ~...l 000 Ethylamine................... ........... . 25 C Ethylbenzene............................ -- 200 Ethyl bromide.......... ...................... 200 Ethyl chloride.... .............. .......... .1,000 Ethyl ether............ .................... 400 Ethyl formate.......................... ...... 100 C Ethyl mercaptan .................... ...... 20 Ethyl silicate.......... --................... 100 Ethylene chlorohydrin - Skin..-- 5 Ethylenediamine_____ --___ _ 10 C Eft; lens glycol dinitrate - Skin 0.2 Ethylene imine - Skin..-- 5 Ethylene oxide:...... .-- 50 2-Ethoxyethanol (Ccllosolve) - Skin____ __ __ 200 2-Ethoxyethanol (Cellosolve)- Skin .................. 200 2-Euhoxyethylacetate (Cellosolve acetate) - Skin .... 100 8S0 2.8 290 35 25 1 5 1 1.5 0.2 360 600 0.1 0.5 1,400 100 1,900 45 870 890 2,600 1,200 300 52 850 16 30 1.2 9 SO 740 740 S40 8 `'4T* - '\JC 5ubionc ppm* Ferbam (ferric dimethyl dithioc3tb3.Tiate) ...................... Fetrovanadium dust ................. .. Fluoride (as F) ........................ .. _ Fluorine ............................ ............. 0.1 Fluorotrichloramethane................ J. 000 C Formaldehyde.............................. Furfural........................................... Furfuty! alcohol............ ............. .. Gasoline......................... ............... Glycidol (2, 3-Epoxy-1 * propanol)..................................... Heptachlor (1, 4. 5, 6. 7. 6, 5 S 50 500 50 8a-hept2ch:oro-3a, 4, 7, 7a-tetrahydro-4, 7- - methanoindans........................... Heptane (n-heptane).................... Hexane (n -hexane)...................... Hexanone (methyl butyl ketone) sec-Hexyl acetate...................... Hexone (methyl isobutyl ketone) 500 500 ICO 50 ICO + Hydrazine - Skin........................... Hydrogen bromide......................... 1 3 C Hydrogen chloride........ ......--...... Hydrogen cyanide-Skin.............. Hydrogen fluoride......................... 5 30 3 Hydrogen peroxide, S03>-............. Hydrogen seleriide......................... t Hydrogen sulfide........................... 1 0.05 _ Hydroquinone................................. C Iodine.......................... .................. Iron oxide fume............................. 0.3 Isophorone............... ........ -......... 25 Isopropylamine............................... 5 Isopropyl glycidyl ether (IGE)..Ketene.____ --...................... ...... f part 50 0.5 Lead arsenate _............................. Lindane (hexachlcrcyelohexane. gamma isomer)............... _......... _ Lithium hydride............................. IS 1 2.5 0.2 5,500 6 20 200 2,000 150 0.5 2,030 1,800 410 29S 410 1.3 10 7 11 2 1.4 0.2 ~ 2 1 15 140 12 240 0.9 0.2 0.15 0.5 0.025 +1964 Addition or delation of **C t)964 Revision * oe Tonrotiv* Volu> 9 ~, - - ; V, : > * V* -f " :"r? *r "t !C H: p 4 's p?m Mg/M*" f. ? ' Magnesium oxide fume............ 15 1 ? r. Maiathion (0,0-dimethyl dithiophosphate of diethyl r r: rercaptosuccinate) - Skin . - IS 2 s 3 Mercury (organic compounds) - Skin............................................. . - 0.01 . 25 100 Metnoxychlar (2, 2-di-p- methaxy-phenyl-1, 1, 1Uichioroethane)........................ . - IS a Metnyl acetate.............................. . 200 Metny! acetylene.......................... .1,000 Methyl acrylate - Skin............... . 10 610 1,650 35 Methylal (dimethoxymethane).....1,000 3,100 Methyl alcohol (methanol).......... 200 2C0 C Methyl bromide - Skin.........-.... . 20 80 .Methyl cellosolve (2-methoxyethanol) Skin....................- . 25 80 Methyl cellosolve acetate (ethylene glycol monomethyl ether acetate) - Skin............. . 25 C Metnyl chloride........................ . 100 120 210 Methyl chloroform (1, 1, 1-tri- chloroethane)........................ . 350 1,900 i Metnylcyclohexane.................- . 500 Metnyicyclohexano!......-............. .. 100 Methylcyclohexanone____ . 100 2,000 470 460 Methyl formate........................ .... .. 100 250 .Methyl isobutyl carbinol f.methyl amyl alcohol)............- 25 f 'Methyl mercaptan.......... . _-- 100 -- C s Methyl styrene.................. ... 100 480 Methylene chloride (dichloromethane)_...... ... 500 Monomethyl aniline -- $kia...._. 2 1,750 9 Molybdenum ( soluble compounds).......... .. --- 5 i (insoluble compounds)-------- .. - IS rl964 Addition o deUtion of **C'* ?1954 Revision - see Tentative Volues Subsione* ppm* Mg/M3** Naphtha (coal tar)..................... . 200 800 Naphtha (petroleum).......... .......... 500 2,000 P - Naphthyiamine___ .................. - A2 Nickel carbonyl............................. 0.001 0.007 Nicotine - Skin............................... 0.5 f Nitric acid ......... ......... ...... ............ p-Nitroaniiine -Skin............... .... 1 6 Nitrobenzene - Skin....................... 1 5 100 310 C Nitrogen dioxide................ ....... ... s 9 C Nitroglycerin + EGON Skin.... 0.2 2 Nitromethane.............................. ... )C0 250 l-NiUopro?ane.............................. 25 90 2*Niopropane............................. 2$ 50 N Nilrosodimethylamine (Ormethylnitrosamjnej Skin . NitrolOluene - Skin.................... .. A3 S -- 30 Octane.................-..................... 500 Oil mist (mineral)_____-- --. -- 2.350 5 Osmium letroxide................. ...... - 0.002 Ozone............. -.................... .... 0.1 0.2 parathion (O. 0*dicthyl 0*p- nitrophenyl thiophespna'.e- - Skin................... ....................... -- 0.1 Pentaborane......... ....... .............. o.oos 0.01 Pentachloronaphthalene Skin.. - 0.5 pentachlorophenol - Skin.......... - 0.5 Pentane.................................. 1.000 2.950 Pentanone (methyl propyl ketone).............--.......... . 200 700 Perchloroethylene (tetrachloroethylene)..................... 100 Perchloromethyl mercaptan___ . 0.1 C70 o.e perchloryl fluoride................... . 3 13.5 Phenol - Skin____ _____ _ .r 5 19 Phenyl glycidyl ether (PG)...... 50 310 Phenylhydtazine Skin................. $ 22 phosdr in (2 - cartomethoxy -l - methyl vinyl dimethyl phosphate)............ ............ . -- 0.1 1964 Addition ut deletion of "C'* t)964 Revision - see Tentative Values --V feSfe to. * Vv-X &' |>:vT;V- "`ir-': Hit.-; &; >v.;. Vs/ 7Z4 '/Lr |g| m sgg eg Subsiunee ppm* Mg/M1** poos2ene (carbonyl chloride).... _ -- Phosphine....................................... phosphoric 3cid............................. 0.3 - 0.4 1 phosphorus (yellow)..................... - 0.1 Phosphorus pentachloride.......... - 1 Phosphorus pentasulfide............ - 1 Phosphorus trichloride................ Picric acid - Skin......................... 0.5 - 3 0.1 platinum (Soluble Salts).............. - 0.002 Propyl acetate............................ 200 840 Propyl alcohol (isopropyl alcohol)....................................... 400 980 Propyl ether (isopropyl ether).... 500 2,100 n-Propyl nitrate........................... 25 no Psopylene dichloiide (1, 2- dichlotopropane)....................... 75 350 Propylene imine - Skin................ 25 60 Propylene oxide............................. 100 Pyrethrum............................. .......... - 240 5 Pyridine..................................... --. 5 IS Qyinone............................................ Rotenone (commercial)................. Selenium compounds (as Se)..... 0.1 -- - 0.4 5 - Sodium fluoroacetate (1030) Skin............................................ Sodium hydroxide................ ........- -- 0.05 2 Stibme.......................... ........... ....... 0.1 0.5 Stoddard solvent........................... 500 2,900 Strychnine....................................... ; Styrene monomer - 0.15 (phenylethylene)................ ...... 100 Sulfur dioxide................................. s 420 13 Sulfur hexafluoride....................... 1.000 6,000 Sulfuric acid................................... _ 1 Sulim monochiotide...................... 1 6 Sulfur pentafluoride........... ........... 0.025 0.25 Sulfuryt fluoride...... 2, 4, ST (2. 4. 5 S . * 20 fcichlorophenoxyacetic acid).. -- 10 TEDP (tetraethyl dithionopyrophosphateJ-Skin.. _ 0.2 tJ964 Addition or deletion of "C** T1964 Revision see Tentative Valves Substance ppm* Mp`M*`* Teflon iRf decomposition products........... TEPP (tetraethyl pyro A4 phosphate} . Skin............. Tellurium .. . .. 1, ), 2, 2-Tei{3chio:ceth3fie 0.05 0.1 -Skin.............. ...... _ . 5 35 j Tetrahvdrofuian . 200 590 Tetranitrorrethone............... . 1 8 Tetryl (2, 4, 6-trimtrophenyi - methylniuamme) - Skin.... Thallium (soluble compounds) 1.5 - Skin.................................. Thiram (tetraxethyt thiuram 0.1 disulfide'.............................. Titanium dioxide......................... * Toluene (toluol)....................... .. . o-Toiuidme Skin.................. CTolyiene-2, 4-dnsocyanace..... Trichloroethylene .......... ............ . Ttichloronaphtha'.ene-Skin...... . 200 f> ' 0.02 100 _ 5 IS 750 22 o.n 520 r, 1, 2, 3-Tfichlo:cprop2ne........ . 50 1, 1, 2-Ttichloto 1. 2, 2- 300 trifluoroethane......................... ..1.000 Triethylamine................................ . 25 Trifluoiomo.iobromome;h3te....... .1,000 Trinitrotoluene-Skin................... -- Trioithocresyl phosphate.......... . Triphenyl phosphate..................... - Turpentine.................. ................... 100 7,600 100 6,100 1.5 0.) 3 560 Uranium (soluble compounds)... . - ] (insoluble compounds)........... C Vanadium (V 20 s dust)....... ....... - - (V2O 3 fume)............................. - 0.06 0. 25 C. 5 0.1 C Vinyl chloride (chioroethyfene)... 50.0 I.3C0 Vinyl toluene ____ -................... . ICO 430 Warfarin (3 a acetonylbenzyQ"*" hydroxycoumarin).._..... ........... - 0.1 C Xylene (xylol)........................- . 200 870 Xyiidine Skin.--__ _________ .. 5 25 +1964 Addition of deletion of **C'* t!964 Revision see Tentative Votues |-it I* ^ <! :*-V .A w v " r; .'.-'Y:-V.7' Sub>ronce ppm* Mg/Mu* TENTATIVE VALUES Yttrium ......................................... -- -- 2iic oxide fume............................. -- 5 Substonce ppm* M'M*** 2itconiufn compounds (as 2r).... - 5 -- SMOatt'vty: fOt permissible concentrations of redio-isotepes *> it. %`t u. S Otpi'tmenl of Commerce. National Bureau of Standards Kjnaaao* 63. ,-M*nmvm Permissible Body jfttf ` Remissible Concentrations of Radi- c*utit-s tn Air and in Water for Occupational Etposure." ijH 5 1953. Also, see U. S. Department of Commerce *ii:ioi"el Bureau of Standards. HanCSoc* 53. "Permissible Dose -.rnal Sources Of ionising Radiation.*' September 24. I?54, era addendum o' April IS. 1958. * Raf* o' vapor or fas per million parts of air by volume a: 25'C a-id 760 mm. H| pressure. Approxmate milligrams of particulate per cu&ie meter o' in i Iru.-bers. See Appedi* A 7I?54 Revision see Tenrorive Veluus ++Anisidme (o. p-iss.7isrs! .. .. ++Ben20yl peioxide..................... Calcium oxide............................. H-Catbatyl (Stvinj (Ri.............. ...... Copper Fume.......................... .. . Ousts & Mists......................... e-tCotton Dust (ra.vi........................ t+Cyclopentadiene.......................... Demeton (Systox) (R)................... *+l. 3-Dichioro-S. S-dimethyl hydantoin.............................. .... 7S o.s 5 & 5 0.1 1.0 1 200 0.1 0.2 rt^- f'.-rw?s;Vr f+Oimethyt 1, 2-dit>romo-2, 2- MINERAL DUSTS s4 Substance m.p.p.c.f.* dichlofoethyl phospnate. (OibiomtiR) ........................ . H-Dimethyiamine............................... 10 3 IS \`&Zl SiUCA Crystalline Quartz, Threshold Limit calculated from the formula.................................. Cristobahte " " ' Amorphous, including natural 250 * &Si02+ 5 + Dimethylfonn.vpids - S>.in . . .. -t-tDi sec. octyl phinaiate (Oi-2- ethylnexyl-phtnalaie)............... Epichlofhydiin........................... .... Ethanolamine................................ . 10 5 3 30 5 19 G d>atomaceous earth ........................... 20 Giaphite .................. ............ ......... . - ISmppcf SILICATES (less than 1% crystalline silica) Asbestos _____ ___ _________________ -- Mica .......................................... Soapstone _____________ ___ _-- Talc ........................................... 5 20 Hafnium........................................ ... . - 0.5 20 e-tHexachloioethane - Skin_______ . 1 Hydiogen Sulfide.......................... . 10 9.7 15 20 ++L. P. C. (Low pressure gas i, '>r'r} Portland Cement ----------------------- 50 (Liquid petroleum gas!............1,000 - "Inert'' or Nuisance Particulates 50 (or 15 mg/m 3 whichever is the smaller) Conversion factors mppcf x 35.3 -- million particles per cubic meter = particles par c.c. H-Maleic anhydride.......................... . - H-Meth3na.......................................... .1.000 Methyl acetylene-propad.ier.e miAtuie, (f/.APPj ................... .1.000 Methylamir.e.................................. . 25 + Methyl mercaptan..................... .. 10 Methyl methacrylate 100 8 - -- 31 20 410 K^y,;. / `v * v,!!,90} ei particles per cubic foot of air, based on tmpinger sample* counted by light-field technics. **T.* percentage of crystalline silica in the formula is the amount determined from air-borne samples, except in those instances in which other methods have been shown to be appiicable. ' C Methylene bis phenylisocyanalei Miners-* v/ool, fibrous glass........ HMonomethyl hydrazine - Skin.... .. Morpholine Skin..... ..... ............. - 0.02 0.2 20 0.2 2 Q35 70 * U Paris of vapor or gas Per million parts of air by volume at 2S*C and 750 mm. Hg pressure * Appro'imate milligrams of pa't'Ci.ia;* per cubic mater of air. *1904 Revision. ++19S4 Additions. 15 mi m m Ife- .V* ' . SvbvOne* M9/M`* Naphthalene.................................... 10 -r-Nickel, metal and soluble compounds.................................. -- rNitric Acid ................................... --p-Nittoch'.orobenzene...TM............ 2 -- v--Nitrogen tfiMuoride....... ............ .. 10 C T-Oxygen difluonde............. ........... --p-Phenylene diamine-Skin........ 0.05 -- -^Phosgene........................-............. 0.1 --rphthalic anhydride............ .......... 2 -r Propane.............................................1,000 ? Propiolactone...................... -- T$eJenium compounds........_...... - -Silver, metal and soluble com pounds....................................... .. -- Tantalum.......................................... -- -1, 1, 1, 2-Tet/achloro-2, 2-difluoroethane................ 500 1, 1, 2, 2-Tetr3ch!oro-l, 2*dtnuo;oethane.............. 500 Tetraethyllead-Skin............ ... -- Tin {inorganic compounds).......... - (organic compounds as Sn) -Skin................... .............. ........ - -Yttrium. ............................... ..... -- 50 1 5 1 29 0.1 0.1 0.4 12 1,800 A5 0.2 0.01 5 4,170 4,170 0.075 2 0.1 1 * ?trti of **po> or (> per million pjrts of air by volume 'i at 2$*C and 760 mm. Hz pressure. ** Approumjle milijrjms o( particulate per cubic meter of a-r. A n.-nbers. See Appendix A -1554 Revisions. --1554 Additions. Appendix A A' Benzidine. Because of high incidence of bladder tumors in man, any exposure, including skin, is extremely hazardous, A1 /o.ffiphthylamine. Because of the extremely high incidence of bladder tumors in workers handling this compound, and the inability to control ex posures, fi-naphthylamine has been prohibited from manufacture, use and other activities that in volve human contact by the State of Pennsylvania. A* N-Nitrasodimetnylamin;. Because of extremely high lonely 'and presumed ca-'c.nojenic potential of this compound, contact b/ an/ route should nol be permitted. _ A* Tellon ^ decomposition products. At least one identi fied component of Teflon decomposition products is extremely icxic. but in the absence of more complete toxicity information and suitable analytic methods, a definite Threshold limit Vatue is not recommended at this t:m; tut au concentrations should be minimal. A* /J-Propiolactone. Because of high acute toxicity and demonstrated skin tumor production in anim3<s. contact by any route should be avoided. Appendix B B. 1 THRESHOLD LIMIT VALUES FOR MIXTURES Y/hen two or more hazardous substances are present, their combined effect, rather than that of either indi vidually. should be given primary consideration, tn the absence of information to the contrary, the effects of the different hazards should be considered as additive. That is. if the sum of Ihe following fractions. b T; Tn exceeds unity, then the threshold UmU of the mixture should be considered as being exceeded. Ciindicates the observed atmospheric concentration, and T the corres ponding threshold limit, (See Example iA.a.). Exceptions to the above rule may be made when there is good reason lo believe that the chief effects of the different harmful substances are net in fact additive, but independent as when purely local effects oa different organs of the body are produced by the various com ponents of the mixture. In such cases the threshold limit ordinarily is exceeded only when at laast one member of the series tC> ct ^ tic.) itself has a value ! T.exceeding unity, (See Example lA.b.1. Antagonistic action or potentiation may occur with some combinations of atmospheric contaminants. Such cases at present must be determined individually. Poten tiating or antagonistic agents are nol necessarily harm ful by themselves. Potentiating effects of exposure to such agents by routes other than that of inhalation Is also possible, e.g. imbibed alcohol and inhaled narcotic (trichloroethylene). Potentiation is characteristically ex hibited at high concentrations, less probably at taw. i.'5-r fi fi pr,'yiV*si;; 'i/tr-r; I -e.-. :$% ssi i-'.-v-jVC When a 6'v'sn operation or process charoclenstica-', emits 3 number of tiorniol dusts, fumes, vjpors 01 gases, it w.n frequently be only feasible to attempt to e.shate the hotard by measurement of a single sub stance. In such cases, the threshold limit used for (ms substance should be reduced by a suitable facto*, the magnitude ol which will depend on the cumber, toxicity and relative quantity of the other contaminants o*<2* canty present Examples of processes wh.ch ae typically associated with two or more harmful atmospheric contaminants are welding, automobile repair, blasting, painting, lacquering, certain foundry operations, diesel exhausts, etc. (Example ?> THRESHOLD LIMIT VALUES FOR MIXTURES EXAMPLES IA General case, where air is analysed for each com ponent. a. ADDJ7JVE EJECTS r T TC, 11 . C.. +- -* _* + c. 1:: 1- + -1 Air contains 5 ppm of carbon tetrachloride (TLV. 10), 20 ppm of ethylene dichforide (TLV.50) and 10 ppm of ethylene dibromide, fiLV. 25). 5 20 10 TO" + IQ" + 2T 65 50~ - 1.3 Threshold limit is exceeded, b. INDEPENDENT EFFECTS Air contains 0.15 mg/mJ of lead (TlV, 0.2) and 0.7 mg/rn1 of sulfuric acid {TLV, 1). -0.7 Threshold limit is not exceeded. IB. Special case when source of contaminant is a mixture and atmospheric composition is assumed similar to that of original material, i.e. vapor pres* sure of each component is the same at the observed temperature. . a ADDITIVE EFFECTS, approximate solution. 1. A mixture of equal parts (!) trichloroethylene (TLV. 100). and (2) methyl chloroform (TLV. 350V 18 c c. C Too ' *3bC " "f c C- T C. Solution applicable to "spot" solvent mixture -sage, where an or nearly an. solvent evaporates. c C 2C ICO ' Tso ^ TT 7C 2C 2C TCO" " 700 ' IT L. - 700 x ~ ^ 155 ppm 16 b Ce^erei Exact Solution for Mixtures of fl Com ponents With Additive Effects and Different Vapor Pressures * `s * (?) C, -- C; -- . -C.-I; (2.11 4. ^ 4. ...-4--i. 0/ the 1W of Partial Pressures, O' C. -- ?* And by Pasulfs Law, <*! Pi - h P,. Combi.*? ;3j and to obtain (Si C: Combining ()), (2.1). and (5!, tie obtain (5, Lil - 1M ^.. * I'K _ LM + ?*:. T I T I, ?J and solving tor T, IU, ^^+-+ffr i-- n or 5 (S.2) T -- i -- 1 i--n S 1-1 fiP.* F*,* ~C ;& 19 $5^3 yv-.v- frianiaitttowiiri tLAfciiU.ifw T " Threshold Limit Value in ppm C -- Vapor concentration 1.1 pp.-rt. p = Vapor pressure of component in solution. p* = Vapor pressure oi pure component. F = Mol fraction of component m solution. a = A constant of proportionality Subscripts 1.2. ... n relate the above quantities to components J.2____n. respectively. Subscript i refers to an arbitrary component from 1 to n Absence of subscript relates the quantity to the mixture. Solution to be applied when there is a reservoir of the solvent mixture whose composition does not change appreciably by evaporation. 1113 WB. Exact Arithmetic Solution of Specific Mixture Mol. wt. Density I Tricolor. ethylene (1) 131.4 1.46 g/mt 100 p* at 25*C Mol frac tion in halfand half solu tion by volume 73mm Hg 0.527 Methylchlo* reform 12) 133.42 1.33 g/ml-350 125mm Hg 0.473 Ftpl*-(0.527)(73)- 38.2 Fsp/- (0/73) (125) -59.2 T =38.2 -f- 59.2 = (97.4) (350) =(97.4) (350) = 177 3^2 +5*2 133.8 + 592 193.0 100 350 T-= 177 ppm (Note difference in T.I.V. when account is taken of vapor pressure and mol fraction in comparison with above example where such account is not taken). 20 2. A mixture of one part cf (!) praihion (TLV. 0.1) and two parts cf !2l iPfi (TlV. 0.5) c, -_c, C. -2C. 0.1 1 0.5" " Tni CPJ * 30, JC,_ . 2C^_ 3( 0.1 ^ 0.5 " Tni 7C,_ 3^ *0.5 " Tni Tm = -y_-0.21 mg/m* 1C. T. L. V. for Mixtures of Mineral Dusts. For mixtures of biologically active mineral dusts the general formula for mixtures may be used. With the ex ception of asbestos, pure minerals arc assigned TLVs of 2.5, 20 or 50. - For 3 mixture containing 80s# talc and 20* quartz, the TLV for 1CQ* of the mixture "C" is given by: C 0.8 0.2 TLV" 20 + 2.5 TLV n??cf Essentially the same result wilt be obtained if the limit of the more (most) toxic componet is used provided the effects are additive. In the above example the limit for 20?* quartz is 10 mppef. For another mixture of 259j quartz 25?* amorphous silica and 50V talc: W+Sf*=7'3^c' ' ... %. pV The limit for 25'* quartz approximates 8 mppe*. 21 Appendix C BASES FOR ASSIGNING LlTyllTING "C" VALUES 8y definition in the Preface, a listed value hear ing a "C** designation refers to `ceiling' value that should not be exceeded; all values should fluctuate below the listed value. In general the bases for assigning or not assigning a *'C" value rest on whether excursions of concentration above a proposed limit tor periods up to IS minutes may result in a) intolerable irritation, b) chronic, or irreversible tissue change, pr e) narcosis of sufficient degree to increase accident proneness.impait self lescue o: materially reduce work efficiency. Jn order for the Committee to decide whether a sub stance is a candidate for a "C" listing, some guidelines must be formulated on the permissive fluctuation abave the limit in terms of the seriousness of the response in the categories a, o. c, given above. For this the factors given in the table below have been used by the Committee. For both technical and practical reasons, the factors have been pegged to the concentration in an inverse manner. It will be noted that as the magnitude of the T. L. V. increases a correspondingly decreased range of fluctuation is permitted; not to decrease the factor for T. L. V.'s of increasing magnitude would permit exposures to large absolute quantities, an undesirable condition, a condition that is minimized at low T. L. V.'s. More over, larger factors at the lower T. L. V/s are con sistent with the difficulties rrt analyzing and con trolling trace quantities. T.l.V. RANGE ppm' or ni/itO T*r T.l.V. Fct9r Examples Toluene diisocyanats-T. L. V.. 0.02 ppm. if permitted to rise above 0.06 ppm may result in sensitization in a single sub sequent exposure. "C* listing lecom,mended on category b. T.l.V. Must pj.n' O' rj/rrl Test U.V. Fjjtar 10 r to ICO 1.5 100 v to 1000 1.25 Methyl styrene-T. L. V. 100 if encountered at levels of 150 ppm viitt prove intense ly irritating, *'C'* listing recommended on category a. Methyl chlotolurm-T. L. V. 35Cppm, at 433 ppm for per iods not exceeding 15 min utes is not expected to re suit in untoward effects relating to category c. No "C" risling recommended. * Whichever unit is applicable As staled in the preface, the some factors may t>? used as guides (or reasonable excursions above the limit for substances to which the lime-weighted average applies. Tr.e tine-weighted average implies that each excursion above the limit is compensated by a com patible excursion below tne limit. Harry B. Ashe E. J. Baier Harold N. MdCPaMpnd.Consultant E. Mastromatteo Allan L. Coleman William F Reindoliar Heivey B. Elkins Bernard Gradois Wayfand J Hayes. Jr. Keith Jacobson Russel G. Scovitt Ralph G Smith Mitchell R Zavon Herbert E. Stokinger. Chairman