Document XO9EKgkMmMZZbDZ3nroXZeQGR

Threshold Limit Values of Airborne Contaminants AND INTENDED CHANGES Adopted By ACGIH For 1970 FMSI-0067 FMSI 02914 T Copyright 1970, by American Conference of Governmental Industrial Hygienists. The American Conference of Governmental Industrial Hygienists will welcome requests for permission to re publish or reprint these Threshold Limit Values. Requests for such permission should be directed to the SecretaryTreasurer, 1014 Broadway, Cincinnati, Ohio 45202. Price Each 1--49 Copies ................................................. 50 -- 999 Copies ............................................. 1000 -- 4999 Copies ....................................... 5000 or more Copies ..................................... 50? 40? 30? 15? Documentation of Threshold Limit Values. A separate companion piece to the TLVs is issued by ACG1H under this title. This publication gives the pertinent scientific information and data with reference to literature sources that were used to base each limit. Each documentation also contains a statement defining the type of response against which the limit is safeguarding the worker. For a better understanding of the TLVs it is essential that the Documentation be consulted when the TLVs are being used. Information concerning the availability of copies of the Documentation of Threshold Limit Values should be directed to the Secretary-Treasurer. PREFACE THRESHOLD LIMIT VALUES FOR 1970 Threshold limit values refer to airborne concentrations of substances and represent conditions under which it is be lieved that nearly all workers may be repeatedly exposed day after day without adverse effect. Because of wide varia tion in individual susceptibility, however, a small percentage of workers may experience discomfort from some substances at concentrations at or below the threshold limit, a smaller percentage may be affected more seriously by aggravation of a pre-existing condition or by development of an occupa tional illness. Simple tests are now available (J. Occup. Med. 9, 537, 1967; Ann. N.Y. Acad. Sci., 151 Art. 2, p. 968, 1968) that may be used to detect those individuals hypersusceptible to a variety of industrial chemicals (respiratory irritants, hemolytic chemicals, organic isocyanates, carbon disul fide). These tests may be used to screen out by appropriate job placement the hyperreactive worker and thus in effect improve this "coverage" of the TLVs. Threshold limit values refer to time-weighted concentra tions for a 7 or 8-hour workday and 40-hour workweek. They should be used as guides in the control of health hazards and should not be used as fine lines between safe and dangerous concentrations. (Exceptions are the substances listed in Appendices A and E and those substances designated with a "C" or Ceiling value. Appendix C.) Time-weighted avqgggjp>>ermit excursions above thp limit provided they are cdmpensatecf by equivalent excur sions below the limit during the workday. In some instances it may be permissible to calculate the average concentration for a workweek rather than for a workday. The degree of permissible excursion is related to the magnitude of the threshold limit value of a particular substance as given in Appendix C. The relationship between threshold limit and permissible excursion is a rule of thumb and in certain cases may not apply. The amount by which threshold limits may be exceeded for short periods without injury to health depends upon a number of factors such as the nature of the contaminant, whether very high concentrations - even for short periods - produce acute poisoning, whether the ef fects are cumulative, the frequency with which high con centrations occur, and the duration of such periods. All factors must be taken into consideration in arriving at de cision as to whether a hazardous condition exists. 1 FMSI 02916 Threshold limits are based on the best available informa tion from industrial experience, from experimental 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 may be a guiding factor for some, where as reasonable freedom from irritation, narcosis, nuisance or other forms of stress may form the basis 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 impairment. There is increasing evidence that physical irritation may initiate, promote or accelerate physical impairment through interaction with other chemical or biologic agents. In spite of the fact that serious injury is not believed likely as a result of exposure to the threshold limit concen trations, the best practice is to maintain concentrations of all atmospheric contaminants as low as is practical. These limits are intended for use in the practice of in dustrial hygiene and should be interpreted and applied only by a person trained in this discipline. They are not intended for use, or for modification for use, (1) as a relative index of hazard or toxicity, (2) in the evaluation or control of community air pollution or air pollution nuisances, (3) in estimating the toxic potential of continuous uninterrupted exposures, (4) as proof or disproof of an existing disease or physical conditions, or (5) for adoption by countries whose working conditions differ from those in the United States of America and where substances and processes differ. Ceiling vs Time-Weighted Average Limits. Although the time-weighted average concentration provides the most satisfactory, practical way of monitoring airborne agents for compliance with the limits, there are certain substances for which it is inappropriate. In the latter group are sub stances which are predominantly fast acting and whose threshold limit is more appropriately based on this particu lar response. Substances with this type 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 brief 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 complete cycle of operations or throughout the work shift. Whereas the ceiling limit places a definite boundary which concentrations should not be permitted to exceed, the timeweighted average limit requires an explicit limit to the ex cursions that are permissible above the listed values. The magnitude of these excursions may be pegged to the magni tude of the threshold 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 for a "C" listing. "Skin" Notation. Listed substances followed by the de signation "Skin" refer to the potential contribution to the over-all exposure by the cutaneous route including mucous membranes and eye, either by airborne, or more particu larly, by direct contact with the substance. Vehicles can alter skin absorption. This attention-calling designation is intended to suggest appropriate measures for the preven tion of cutaneous absorption so that the threshold limit is not invalidated. Mixtures. Special consideration should be given also to the application of the TLVs in assessing the health hazards which may be associated with exposure to mixtures of two or more substances. A brief discussion of basic considerations involved in developing threshold limit values for mixtures, and methods for their development, amplified by specific examples are given in Appendix B. Nuisance Dusts. In contrast to fibrogenic dusts which cause scar tissue to be formed in lungs when inhaled in ex cessive amounts, so-called "nuisance" dusts have a long history of little adverse effect on lungs and do not produce significant organic disease or toxic effect when exposures are kept under reasonable control. The nuisance dusts have also been called (biologically) "inert" dusts, but the latter term is inappropriate to the extent that there is no dust which does not evoke some cellular response in the lung when inhaled in sufficient amount. However, the lung-tissue re action caused by inhalation of nuisance dusts has the follow ing characteristics: 1) The architecture of the air spaces remains intact. 2) Collagen (scar tissue) is not formed to a significant extent. 3) The tissue reaction is potentially re versible. Excessive concentrations of nuisance dusts in the work room air may seriously reduce visibility (iron oxide), may cause unpleasant deposits in the eyes, ears and nasal pass ages (Portland Cement dust), or cause injury to the skin or mucous membranes by chemical or mechanical action per se or by the rigorous skin cleansing procedures necessary for their removal. 3 FMSI 02918 A threshold limit of 10mg/M3, or 30 mppcf, of total dust < 1% Si02, whichever is less, is recommended for sub stances in these categories and for which no specific thres hold limits have been assigned. This limit, for a normal workday, does not apply to brief exposures at higher concen trations. 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. Some "inert" particulates are given in Appendix D. Simple Asphyxiants - "Inert" Gases or Vapors. A number of gases and vapors, when present in high concentrations in air, act primarily as simple asphyxiants without other signi ficant physiologic effects. A TLV may not be recommended for each simple asphyxiant because the limiting factor is the available oxygen. The minimal oxygen content should be 18 percent by volume under normal atmospheric pressure (equivalent to a partial pressure, p02 of 135 mm Hg). Atmos pheres deficient in 02 do not provide adequate warning and most simple asphyxiants are ordorless. Several simple asphyxiants present an explosion hazard. Account should be taken of this factor in limiting the concentration of the asphyxiant. Specific examples are listed in Appendix E. Physical Factors. It is recognized that such physical factors as heat, ultraviolet and ionizing radiation, humidity, abnormal pressure (altitude) and the like may place added stress on the body so that the effects from exposure at a threshold limit may be altered. Most of 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 to moderate deviations from normal environments, the safety factors of most substances are not of such a magnitude as to take care of gross devia tions. For example, continuous work at temperatures above 90F or over-time extending the workweek more than 25%, might be considered gross deviations. In such instances judgment must be exercised in the proper adjustments of the threshold limit values. "Notice of Intent." At the beginning of each year, proposed actions of the Committee for the forthcoming year are issued in the form of a "Notice of Intent." This Notice provides not only an opportunity for comment, but solicits suggestions of substances to be added to the list. The suggestions should be accompanied by substantiating evidence. The list of Intended Changes follows the Adopted Values in the TLV booklet. As Legislative Code. The Conference recognizes that the TLVs may be adopted in legislative codes and regulations. If so used, the intent of the concepts contained in the Preface 4 FMSI 02919 should be maintained and provisions should be made to keep the list current. These values are reviewed annually by the Committee on Threshold Limits for revision or additions, as further information becomes available. Reprint Permission. This publication may be reprinted provided that written permission is obtained from the Secre tary-Treasurer of the Conference and that it be published in its entirety. 5 FMSI 02920 Subftancc ADOPTED VALUES {In Alphabetical Order) ppm') m,,g,/Mu3 b)' Abate ..................................................... Acetaldehyde ........................................ Acetic acid............................................ Acetic anhydride.................................. Acetone................................................. Acetonitrile .......................................... Acetylene................................................ Acetylene dichloride, see 1, 2- Dichloroethylene............................... Acetylene tetrabromide....................... Acrolein ................................................ Acrylamide-Skin .................................. Acrylonitrile-Skin................................. Aldrin-Skin............................................ Allyl alcohol-Skin................................ Allyl chloride........................................ **C Allyl glycidyl ether (AGE)................... Allyl propyl disulfide........................... Alundum (AI2O3) .................................. 2-Aminoethanol, see Ethanolamine ... 2-Aminopyridine.................................. ** Ammonia................................................ Ammonium sulfamate (Ammate).......... n-Amyl acetate .................................... sec-Amyl acetate ................................. Aniline-Skin.......................................... Anisidlne (o, p-isomers)-Skin ., Antimony & compounds (as Sb) ANTU (alpha naphthyl thiourea) Argon .................................................... Arsenic & Compounds (as As).............. Arsine................................................... Azinphos-methyl-Skin........................... Barium (soluble compounds)................ C Benzene (benzol)-Skin ......................... Benzidine-Skin...................................... p-Benzoquincme, see Quinone.............. Benzoyl peroxide............... Benzyl chloride.................................... Beryllium.............................................. Biphenyl, see Diphenyl ....................... Bisphenol A, see Diglycidyl ether .... Boron oxide .......................................... Boron tribromide ................................. C Boron trifluoride ................................. Bromine................................................. * Bromine pentafluoride ................. .. Bromoform-Skin.................................. Butadiene (1, 3-butadiene)................... Butanethioi, see Butyl mercaptan .... 2-Butanone ............................................ 2-Butaxy ethanol (Butyl Cellosolve) - Skin ........... Butyl acetate (n-butyl acetate)............ -- 200 10 5 1,000 40 E -- 1 0.1 -- 20 -- 2 1 10 2 -- -- 0.5 50 -- 100 125 5 E - 0.05 -- -- 25 -- -- -- 1 -- -- 1 1 0.1 0.1 0.5 1,000 -- 200 50 150 IS 360 25 20 2,400 70 -- -- 14 0.25 0.3 45 0.25 S 3 45 12 D -- 2 35 15 525 650 19 0.5 0.5 0.3 0.5 0.2 0.2 0.5 80 Al 5 5 0.002 15 10 3 0.7 0.7 5 2,200 590 240 710 a) Parts of vapor or gas per million parts of contaminated air by volume at 25C and 760 mm. Hg pressure. b) Approximate milligrams of particulate per cubic meter of air. *+ See Notice of Intended Changes Capital letters refer to Appendices. 6 FMSI 02921 Substance ppm*^ sec-Butyl acetate ................................. 200 tert-Butyl acetate................................. Butyl alcohol .............................. sec-Butyl alcohol ................................ 200 100 150 tert-Butyl alcohol................................. 100 C Butylamlne-Skin ................................... 5 C tert-Butyl chromate (as C1O3) - Skin . n-Butyl glycidyl ether (BGE)............. -- 50 * Butyl mercaptan .................................. p-tert-Butyltoluene............................... 0,5 10 Cadmium (Metal dust and soluble salts) -- *C Cadmium oxide fume (as Cd) ............. -- Calcium carbonate ............................... -- Calcium arsenate ................................ Calcium oxide ...................................... -- -- ** Camphor (Synthetic) ............................. 2 Carbary1 (Sevin ) ............................. - Carbon black ........................................ -- Carbon dioxide...................................... 5,000 Carbon disullide-Skin........................... 20 Carbon monoxide.................................. 50 Carbon tetrachloride-Skin................... Cellulose (paper fiber)......................... 10 -- Chlordane-Skin ................................... -- Chlorinated camphene-Skin................. -- Chlorinated diphenyl oxide ................. * Chlorine ................................................ Chlorine dioxide ................................... -1 0.1 C Chlorine trifluoride ............................. 0.1 C Chloroacetaldehyde ............................. 1 -Chloroacetophenone (phenacylchloride)............................................ 0.05 Chlorobenzene (monochlorobenzene).. 75 0-Chlorobenzylidene malononitrile (OCBM).............................................. 0.05 Chlorobromomethane ........................... 200 2-Chloro-l, 3-butadiene, see Chloroprene......................... -- Chlorodiphenyl (42% Chlorine} - Skin . -- Chlorodiphenyl (54% Chlorine) - Skin . -- 1- Chloro, 2, 3-epoxypropane, see Epichlorhydrin.................................. -- 2-Chloroethanol, see Ethylene chlorohydrln .................................... Chloroethylene, see Vinyl choride ... C Chloroform (trichloromethane) .......... 1-Chloro-l-nitropropane..................... " -- 50 20 Chloropicrln ........................................ Chloroprene (2-chloro-l, 3-butadiene) 0.1 -Skin .................................................. 25 Chromic acid and chromates (as CrOs) Chromium, sol. chromic, chromous -- salts as Cr ..................................... Metal & insol. salts......................... -- -- Coal tar pitch volatiles (benzene soluble fraction) anthracene, BaP, phenanthrene, acridine, chrysene, pyrene) .............................................. -- * 1970 Addition ** See Notice of Intended Changes mg/M^ ^ 950 950 300 450 300 15 0.1 270 1.5 50 0.2 0.1 D 1 5 -- 5 3.5 9,000 60 55 65 D 0.5 >5 0.5 3 0.3 0.4 3 0.3 350 0.4 1,050 -- 1 5 -- -- 240 10O 90 0.1 5 l 0.2* ** 7 FMSI 02922 Substance ppm*) Cobalt, metal fume & dust ................. Copper fume.......................................... Dusts and Mists................................ Corundum (AI2O3)................................ Cotton dust (raw).................................. Crag herbicide ................................ Cresol (all isomers) - Skin................. Crotonaldehyde .................................... -- _ -- _ 5 2 Cumene-Skin ........................................ 50 Cyanide (as CN)-Skin........................... * Cyanogen ................................................ Cyclohexane.......................................... Cyclohexanol ........................................ 10 300 50 Cyclohexanone...................................... Cyclohexene.......................................... Cyclopentadiene .................................... 50 300 75 2, 4-D................................................... DDT-Skin .............................................. -- DDVP, see Dichlorvos......................... Decaborane-Sktn ................................... 0.05 Demeton -Skin ................................. -- Diacetone alcohol (4-hydroxy4-methyl-2-pentanone)..................... 50 1, 2-Diaminoethane, see Ethylene- diamine .............................................. Diazomethane ...................................... Diborane ................................................ 0.2 0.1 C 1, 2-Dibromoethane (ethylene dlbromide)-Skin ............................... Dibutyl phosphate ................................ Dibutylphthalate ..................... .. *C Dichloroacetylene................................. C o-Dichlorobenzene ............................... p-Dichlorobenzene ............................... 25 1 _ 0.1 50 75 Dichlorodifluoromethane..................... 1, 3-Dichloro-5, 5-dimethyl hydantoin 1, 1-Dichloroethane............................. 1, 2-Dichloroethane............................. 1, 2-Dichloroethylene ......................... C Dichloroethyl ether-Skin..................... Dichloromethane, see Methylene- chloride .............................................. Dichloromonofluo.'omethane................. C 1, 1-Dichloro-l-nitroethane ................ 1,000 _ 100 50 200 15 _ 1,000 10 1, 2-Dlchloropropane, see Propylenedichloride ............................... _ Dichlorotetrafluoroethane................... Dichlorvos (DDVP)-Skin ..................... Dieldrin-Skin........................................ 1, OOO __ Diethylamine ........................................ 25 Diethylamino ethanol-Skin................... 10 **C Diethylene triamine-Skin..................... Diethylether, see Ethyl ether.............. _10 Difluorodibromomethane..................... 100 C Diglycidyl ether (DGE)......................... 0.5 Dihydroxybenzene, see Hydroquinone . Diisobutyl ketone.................................. 50 Diisopropylamlne-Skin..................... . * 5 1970 Ad<Ution * See Notice of Intended Changes 0.1 0.1 1 D 1 15 22 6 245 5 -- 1,050 200 200 1,015 200 10 1 0.3 0.1 240 0.4 0.1 190 5 5 0.4 300 450 4,950 0.2 400 200 790 90 4,200 60 -- 7,000 1 0.2S 75 50 42 -860 2.8 290 20 8 FMSI 02923 IT Subflutcc ppm** Dimethaxymethane, see Methylal .... Dimethyl acetamide-Skin..................... Dtmethylamine......................... ............. 10 10 Dimethylaminobenzene, see Xylidene . Dlmethylaniline (N-dimethylaniline)- Skin ................................................... 5 Dimethylbenzene, see Xylene............. Dimethyl X, 2-dibromo-2, 2-di- chloroethyl phosphate, (Dibrom) ... Dimethylformamlde-Skin ................... 10 2,6-Dimethylheptanone, see DUsobutyl ketone ............................. 1, 1-Dimethylhydrazine-Skin.............. 0.5 Dimethylphthalate................................. Dimethylsulfate-Skin .......................... 1 Dinitrobenzene (all isomers)-Skin .... Dinitro-o-cresol-Skin ......................... Dinitrotoluene-Skln ............................. Dioxane (Diethylene dioxide)-Skin .... 100 Diphenyl ................................................ Diphenyl amine ..................... .............. 0.2 Dlphenylmethane diisocyanate (see Methylene bisphenyl isocyanate (MDI).................................................. Dipropylene glycol methyl ether-Skin . 100 Di-sec, octyl phthalate (Dl-2- ethylhexylphthalate)........................... Emery .................................................... * Endosulfan (Thiodan )-Skin ............ Endrin-Skin .......................................... Eplchlorhydrin-Skin............................. 5 EPN-Skin .............................................. ec-.- __ 1, 2-Epoxypropane, see Propylene- oxide .................................................. 2, 3-Epoxy-l-propanol, see Glycidol . Ethane.................................................... Ethanethiol, see Ethylmercaptan........ Ethanolamine........................................ 2-Ethoxyethanol-Skin........................... E 3 200 2-Ethoxyethylacetate (Cellosolve acetate)-Skin ..................................... Ethyl acetate ........................................ Ethyl aerylate-Skin............................... Ethyl alcohol (ethanol) ......................... Ethylamine............................................ Ethyl sec-amyl ketone (5-methyl- 3-heptanone) ..................................... Ethyl benzene ...................................... Ethyl bromide ...................................... Ethyl butyl ketone (3-Heptanone)........ Ethyl chloride ...................................... Ethyl ether............................................ Ethyl formate ............................. ...... Ethyl mercaptan ................................... Ethyl silicate........................................ Ethylene ................................................ Ethylene chlorohydrln-Skin................. 100 400 25 1,000 10 25 100 200 50 1,000 400 100 0.5 100 E 5 m*/MSb> 35 18 25 3 30 1 5 5 1 0.2 1.5 360 1 10 600 5 D 0.1 0.1 19 0.5 6 740 540 1,400 100 1,900 18 130 435 890 230 2, 600 1,200 300 1 850 16 1970 Addition See Notice ot Intended Changes 9 FMSI 02924 T Substance ppm** Ethylenediamine ................................ . Ethylene dibromide, see 1, 2- Dibromoethane ................................. Ethylene dichloride, see 1, 2Dichloroethane ..................... ........... C Ethylene glycol dinitrate and/or Nitroglycerin-Skin ........................... Ethylene glycol monomethyl ether acetate, see Methyl cellosolve acetate .............................................. Ethylene imine-Skin............................. Ethylene oxide................................... Ethylidlne chloride, see 1, 1-Di- chloroethane .................................... N-Ethylmorpholine-Skin ..................... Ferbam.................................................. Ferrovanadium dust............................. Fibrous glass ...................................... Fluoride (as F) .................................... Fluorine ................................................ Fluorotrichloromethane ................... **C Formaldehyde ...................................... Formic acid.......................................... Furfural-Skin........................................ Furfuryl alcohol .................................. Gasoline ................................................ Glycerine mist...................................... Glycidol (2, 3-Epoxy-l-propanol) .... Glycol monoethyl ether, see 2- Ethoxyethanol.................................... Graphite, (Synthetic)............................. Guthion, see Azinphosmethyl............ Gypsum................................................. Hafnium.................................................. Helium.................................................... Heptachlor-Skin.................................... Heptane (n-heptane) ............................. Hexachloroethane-Skin......................... Hexachloronaphthalene-Skin................ Hexane (n-hexane)................................. 2-Hexanone............................................ Hexone (Methyl isobutyl ketone)........... sec-Hexyl acetate................................. Hydrazine-Skin .................................... Hydrogen................................................ Hydrogen bromide................................. C Hydrogen chloride................................. Hydrogen cyanide-Skin......................... Hydrogen fluoride................................. Hydrogen peroxide ............................... Hydrogen selenide....................... . Hydrogen sulfide.................................. Hydroquinone........................................ * Indene ................................................... 10 -- -- 0.2<*) -- 0.5 50 -- 20 -- -- -- -- 0.1 1,000 5 5 5 50 -- -- 50 -- -- -- -- -- E -- 500 1 -- 500 100 100 50 1 E 3 5 10 3 1 0.05 10 -- 10 mg/M^ **) 25 -- -- -- -- 1 90 -- 94 15 1 D 2.5 0.2 5,600 6 9 20 200 A3 D 150 -- D -- D 0,5 -- 0.5 2,000 10 0.2 1,800 410 410 300 1.3 -- 10 7 11 2 1.4 0.2 15 2 45 d) An atmospheric concentration of not more than 0.02 ppm, or personal protection may be necessary to avoid headache. * 1970 Addition *' See Notice of Intended Changes 10 FMSI 02925 Subttancc ppmm) Indium and compounds, as In.............. C Iodine..................................................... Iron oxide fume.................................... Iron salts, soluble, as Fe................... Isoamyl acetate.................................... Isoamyl alcohol.................................... Isobutyl acetate.................................... Isobutyl alcohol........................ Isophorone ............................................ Isopropyl acetate................................... Isopropyl alcohol................................... Isopropylamine .................. Isopropylether ....................................... Isopropyl glycidyl ether (IGE) ......... Kaolin ................................................... Ketene.................................................... Lead....................................................... Lead arsenate ...................................... Limestone.............................................. Lindane-Skin ......................................... Lithium hydride.................................... L. P. G. {Liquified petroleum gas) .... Magnesite.............................................. Magnesium oxide fume......................... Malathion-Skin ..................................... Maleic anhydride.................................. C Manganese and compounds, as Mn.... Marble.................................................... ** Mercury-Skin........................................ ** Mercury (organic compounds)-Skin ... Mesityl oxide ........................................ Methane................................................. Methanethiol, see Methyl mercaptan.. Methoxychlor ...................................... 2-M^thoxyethanol, see Methyl cellosolve............................................ Methyl acetate ...................................... Methyl acetylene (propyne)................... Methyl acetylene- propadiene mixture (MAPP)................................................ Methyl acrylate-Skin............................. Methylal (dimethoxymethane) .............. Methyl alcohol (methanol) ................... Methylamine.......................................... Methyl amyl alcohol, see Methyl isobutyl carbinol................................ * Methyl isoamyl ketone......................... Methyl (n- amyl) ketone (2-Heptanone). C Methyl bromide-Sldn............................. Methyl butyl ketone, see 2-Hexanone . Methyl cellosolve-Skin......................... Methyl cellosolve acetate-Skin............ **C Methyl chloride.................................... Methyl chloroform................................ Methylcyclohexane...................... Methylcyclohexanol............................... -- 0.1 -- -- 100 100 150 100 25 250 400 5 500 50 -- 0.5 - -- - -- -- 1,000 -- -- -- 0.25 -- -- -- -- 25 E -- -- -- 200 1,000 1,000 10 1,000 200 10 -100 100 20 -- 25 25 100 350 500 100 mil*Is b> 0.1 1 10 1 525 360 700 300 140 950 980 12 2,100 240 D 0.9 0.2 0.15 D 0.5 0.025 1,800 D 15 15 1 5 D 0.1 0.01 100 15 610 1,650 1,800 35 3,100 260 12 475 465 80 80 120 210 1,900 2,000 470 V1970 Addition * See Notice of Intended Changes 11 FMSI 02926 Substance ppm*) o-Methylcyclohexanone-Skin............... Methyl ethyl ketone (MEK), see 2-Butsuwne........................................ Methyl formate .................................... Methyl iodide - Skin............................. Methyl isobutyl carblnol-Skin ............ Methyl isobutyl ketone, see Hexone... Methyl Isocyanate - Skin..................... Methyl mercaptan................................ Methyl methacrylate............................. Methyl propyl ketone, see 2-Pentanone C Methyl silicate...................................... C a Methyl styrene.................................. C Methylene blsphenyl isocyanate (MDI). Methylene chloride (dlchloromethane). Molybdenum (soluble compounds)........ (insoluble compounds) ... Monomethyl aniline-Skin..................... C Monomethyl hydrazine-Skln................. Morpholine-Skin.................................... Naphtha (coal tar) ................................ Naphthalene............................................ $ -Naphthylamine ................................ Neon....................................................... Nickel carbonyl.................................... Nickel, metal and soluble cmpds, as Ni Nicotine-Skin........................................ Nitric acid.............................................. Nitric oxide............................................ p-NitroaniUne-Skin ............................. Nitrobenzene-Sldn................................ p-Nitrochlorobenzene-Skin ............... Nitroethane............................................ Nitrogen................................................. C Nitrogen dioxide.................................... Nitrogen trifluoride ............................. Nitroglycerin- Skin................................. Nltromethane........................................ 1-Nitropropane...................................... 2-Nitropropane...................................... N-Nitrosodlmethylamlne (dimethyl- nitro0oamine)-Skln........................... Nltrotoluene- Skin.................................. Nltrotrichloromethane, see Chloroplcrln...................................... Nitrous oxide........................................ Octacbloronaphthalene-Skln ................ * Octane..................................................... * Oil mist, particulate............................. * Oil mist, vapor.................................... Osmium tetroxlde................................. Oxalic acid............................................ Oxygen dlfluoride.................................. Ozone ..................................................... Paraquat-Skin........................................ 100 -- 100 5 25 -- 0.02 0.5 100 -- 5 100 0.02 500 -- -- 2 0.2 20 100 10 -- E 0.001 --- 2 25 1 1 -- 100 E 5 10 0.2 100 25 25 -- 5 -- E -- 400 1) A3 -- -- 0.05 0.1 h) As sampled by method that does not collect vapor. i) According to analytically determined composition. - 1970 Addition +* See Notice of Intended Changes 460 -250 26 100 -- 0.05 1 410 -- 30 480 0.2 1,740 5 15 9 0.35 70 400 50 A1 -0.007 1 0.5 5 30 6 5 1 310 -- 9 29 2 250 90 90 Al 30 -- 0.1 1,900 5h -- 0.002 1 0.1 0.2 0.5 12 FMSI 02927 Substance Parathion-Skin...................................... Pentaborane.......................................... Pentachloronaphthalene-Skin .............. Pentachlorophenol-Skin....................... Pentaerythrltol...................................... * Pentane............... 2-Pentanone.......................................... Perchloroethylene................................. Perchloromethyl mercaptan............... Perchloryl fluoride............................... * Petroleum Distillates (naphtha).......... Phenol-Skin............................................ p-Phenylene diamine-Skin................... Phenyl ether (vapor)............................. Phenyl ether-Biphenyl mixture (vapor) Phenylethylene, see Styrene................ Phenyl glycidyl ether (PGE) ................ Phenylhydrazine-Skln........................... Phosdrin (Mevinphos )-Skin.............. Phosgene (carbonyl chloride) .............. Phpsphine................................................ Phosphoric acid..................................... Phosphorus (yellow)............................. Phosphorus pentachloride.................... Phosphorus pentasulfide ..................... Phosphorus trichloride ....................... Phthalic anhydride ............................... Picric acid-Skin ................................... Pival (2-Pivalyl-l, 3-lndandione) ... Plaster oi Paris ................................... Platinum (Soluble Salts) as Pt.............. Polytetrafluoroethylene decomposition products.............................................. Propane.................................................. 0 Propiolactone .................................... Propargyl alcohol-Skin ....................... n-Propyl acetate................................... Propyl alcohol...................................... n-Propyl nitrate ................................... Propylene dichloride ........................... Propylene imlne-Skin........................... Propylene oxide.................................... Propyne, see Methylacetylene............ Pyrethrum ............................................ Pyridine ........................................... Quinone.................................................. RDX-Skin .............................................. Rhodium, Metal fume anddusts, as Rh Soluble salts...................................... Ronnel.................................................... Rotenone (commercial) ....................... Rouge..................................................... Selenium compounds (as Se)................ Selenium hexafluoride ......................... Silicon carbide...................................... -0.005 -- -- -500 200 100 0.1 3 1) A3 5 -- 1 1 -- 10 5 -- 0.1 0.3 -- -- -- -- 0.5 2 -- - E -- 1 200 200 25 75 2 100 -- -- 5 0.1 -- -- -- -- -- -- -- 0.05 -- i) According to analytically datermined composition. Capital letters refer to Appendices. 1970 Addition ** See Notice of Intended Changes mg/MS b> 0.1 0.01 0.5 0.5 D 1,500 700 670 0.8 13.5 19 0.1 7 7 60 22 0.1 0.4 0.4 1 0.1 1 1 3 12 0.1 0.1 D 0.002 A* Al 840 500 110 350 5 240 5 15 0.4 1.5 0.1 0.001 10 5 D 0.2 0.4 D 13 FMSI 02928 IT Substance pproa) Silver, metal and soluble compounds . Sodium fluoroacetate (ld80)-Skin ..... Sodium hydroxide ................................. Stibine................. ................................. Starch ................................................... 0.1 * Stoddard solvent ................. ,............... 200 Strychnine.............................................. **C Styrene monomer (phenylethylene) ... 100 Sucrose .................................................. Sulfur dioxide........................................ 5 Sulfur hexafluoride............................... 1,000 Sulfuric acid.......................................... Sulfur monochloride............................. 1 Sulfur pentafluoride ............................. Sulfuryl fluoride ................................... Systax, see Demeton ....................... 0.025 5 2, *, 5 T................................................ Tantalum................................................ TEDP-Skln............................................ Teflon decomposition products........ Tellurium.............................................. Tellurium hexafluoride ....................... TEPP-Skin ............................................ 0.02 -- C Terphenyls ............................................ 1 1, 1, 1, 2-Tetrachloro-2, 2-dl- fluoroethane...................................... 500 1, 1, 2, 2-Tetrachloro-l, 2-di- fluoroethane...................................... 1, 1, 2, 2-Tetrachloroethane-Skln ... 500 5 Tetrachloroethylene, see Per- chloroethylene......................... Tetrachloromethane, see Carbon tetrachloride .................................... -- Tetrachloronaphthalene-Skin .............. -- Tetraethyl lead (as Pb)-Skin................ Tetrahydrofuran ................................... -- 200 Tetramethyl lead (as Pb)-Skln .......... -- Tetramethyl succinonitrile-Skin ........ 0.5 Tetranltromethane ............................... Tetryl (2, 4, 6-trinitrophenyl- methylnitramine)-Skin .................. 1 -- Thallium (soluble compounds)-Skin as T1 Thiram ................................................. Tin (inorganic cmpds, except SnH4 and Sn02) .......................................... -- Tin (organic cmpds)..................... -- Tin oxide .............................................. -- Titanium dioxide................................... -- Toluene (toluol).................................... C Toluene-2, 4-dilsocyanate ................. 200 0.02 o-Toluidine-Skin ............................... 5 Toxaphene, see Chlorinated camphene -- Tributyl phosphate ............................... -- 1, 1, 1-Trichloroethane, see Methyl chloroform............................ - 1, 1, 2-Trichloroethane-Skin..... ....... 10 mg/M^ 0.01 0.05 2 0.5 D 1,150 0.15 420 D 13 6,000 1 6 0.25 20 10 5 0.1 0.2 0.05 9 4,170 4,170 35 2 0.100 j) 590 0.150 i) 3 8 1.5 0.1 5 2 0.1 D D 750 0.14 22 5 45 j) For control of general room air, biologic monitoring is essential for personnel control. 1970 Addition * See Notice of Intended Changes 14 FMSI 02929 Substance ppmm) Trichloroethylene................................ 100 Trichlororaethane, jBee Chloroform .. -- Trichloronaphthalene-Skin ................. -- 1, 2, 3-Trichloropropane................... 50 1, 1, 2-Trichloro 1, 2, 2-tri- fluoroethane...................................... 1,000 Triethylamlne ...................................... 25 Trifluoromonobromomethane.............. 1,000 Trimethyl benzene .............................. 25 2, 4, 6-Trinitrophenol, see Picric acid -- 2, 4, 6-Trinltrophenylmethylnitramine, see Tetryl........................ -- Trinitrotoluene-Skin............................. -- Triorthocresyl phosphate ................... -- Triphenyl phosphate............................. -- Tungsten & compounds, as W Soluble................................................ -- Insoluble............................................ -- Turpentine ............................................ 100 Uranium (natural) sol. & insol. compounds as U................................. -- C Vanadium (V2O5 dust) ........................ -- (V 2O5 fume) ....................... -- Vinyl benzene, see Styrene................. **C Vinyl chloride ...................................... -- 500 Vinylcyanide, see Acrylonitrile.......... -- Vinyl toluene ........................................ 100 Warfarin................................................ -- Xylene (xylol)........................................ 100 Xylldine-Skin........................................ 5 Yttrium.................................................. -- Zinc chloride fume............................... -- Zinc oxide fume..................................... -- Zirconium compounds (as Zr) ............ -- mg/M ^ 535 -- 5 300 7,800 100 6,100 120 -- -- 1.5 0.1 3 1 5 560 0.2 0.5 0.1 -- 1,300 -- 480 0.1 435 25 1 1 5 5 Radioactivity: For permissible concentrations of radioisotopes in air, see U.S. Department of Commerce, National Bureau of Standards, Handbook 69, "Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure," June 5, 1959. Also, see U.S. Department of Commerce National Bureau of Standards, Handbook 59, "Permissible Dose from External Sources of Ionizing Radiation," September 24, 1954, and addendum of April 15, 1958. ** 1970 Addition ** See Notice of Intended Changes 15 FMSI 02930 Substance MINERAL DUSTS m.p.p.cXc) SILICA Crystalline ** Quartz, Threshold Limit calculated from the formula .................................. 250 " %sT62+5 ** Cristobalite " " " Amorphous, including natural diatomaceous earth ............................ 20 SILICATES (lesB than 1% crystalline silica) ** Asbestos, all types ................................. Mica........................................................... Portland Cement...................................... Soapstone .................................................. Talc (non-asbestiform)............................. Talc (fibrous), use asbestos limit.......... Tremolite, see asbestos ......................... 5 20 50 20 20 -- -- Graphite (natural) ........................... ** "Inert" or Nuisance Particulates see Appendix D 50 (or 15 mg/M3 whichever is the smaller) of total dust < 1% SIO2 Conversion factors mppc! x 35.3 = million particles per cubic meter - particles per c.c. ^7 />/,' 1. s JTx.At', ) Millions of particles per cubic foot of air, based on lmpinger samples counted by light-field technics. f) The percentage of crystalline silica In the formula is the amount determined from airborne samples, except in those instances in which other methods have been shown to be applicable.** ** See Notice of Intended Changes for Mineral Dusts. 16 FMSI 02931 NOTICE OF INTENDED CHANGES (for 1970) These substances, with their corresponding values, com prise those for which either a limit has been proposed for the first time, or for which a change in the "Adopted" listing has been proposed, hi both cases, the proposed limits should be considered trial limits that will remain inthe listing for a period of at least two years. During this time, the previously Adopted Limit will remain in effect. If, alter two years no evidence comes to light that questions the appropriateness of the values herein, the values will be placed in the "Adopted" list. Documentation is available for each of these substances. Substance ppm 2-Acetylamlnofluorene-Skin.............. + Allyl glycldyl ether............................ 4-Amlnodiphenyl-Skin......................... + Ammonia............................................ + Ammonium chloride fume .................. Asphalt (petroleum) fumes.................. + Butyl lactate....................................... + Camphor (synthetic)............................ + Diazlnon-Skln..................................... + 2-N Dibutylamino ethanol-Skin........... Dichlorobenzidine-Sldn....................... - Diethylene triamine-Skin.................... 4-Dimethylaminoazobenzene.............. Fibrous glass..................................... + C Formaldehyde..................................... + Iron pentacarbonyl.............................. + Mercury (Alkyl compounds) - Skin---+ Mercury (all forma except alkyl)....... + Methyl chloride.................................... Methyl 2-cyanoacrylate....................... + Methylcylopentadienyl manganese tricarbonyl (as Mn)......................... Methyl demeton-Skin........................... Methyl parathion-Skin......................... Phenothiazine-Sldn.................................. + Rosin Core Solder, pyrolysis products -5 -- 25 -- -- 1 2 -- 2 -- I -- g) -- 2 0.01 -- " 100 2 0.1 -- -- -- - Styrene................................................ 100 + C Subttllsins (Proteolytic enzymeB)....... -- + Vanadium (V2O5 Fume) as V Vinyl acetate....................................... + Vinyl chloride..................................... + Wood dust (non allergenic) 10 200 mg/M^ A 2b 18 10 5 5 12 0.1 $ 4 Al D 3 0.08 0.01 0.05 210 0.2 0.5 0.2 5 0.1 (as alde hyde) SO 0.0003 (as 100% pure crystal line en zyme) 0.05 30 770 5 + 1970 Revision or Addition Capital letters refer to Appendices g) < 5-7 M Diameter, No TLV ior coarse fibrous glass has yet been set. 17 FMSI 02932 NOTICE OF INTENDED CHANGES (Confd) MINERAL DUSTS SUBSTANCE TLV + Asbestos (All types) + Coal dust (bituminous) Cristobal!te + 'Inert' or Nuisance Parti culates + Quartz Silica, fused Tridymite 5 libers/ml > 5/i in length11) 2 mg/m3 (respirable dust)m) Use one-half the value calculated from the count or mass formulae for quartz. 10 mg/M3 or 30 mppcf (whichever is the smaller) of total dust < 1% Si2n) 300 TLVinmppcf: "Ssio2+id- TLV for respirable dust in mg/ra3: 10 mg/M3^ % Respirable quartz + 2 TLV for ''total dust", respirable and nonrespirable: 30 mg/M3 % quartz + 3 Use quartz formulae Use one-half the value calculated from formulae for quartz. + 1970 Revision or Addition k) As determined by the membrane lilter method at 430 X magnification phase contrast illumination. Concentrations > 5 fibers/ml, but not to exceed 10, may be permitted for 15-minute periods each hour up to five times daily. m) "Respirable" dust as defined by the British Medical Research Council Criteria (1) and as sampled by a device producing equivalent results (2). (1) Hatch, T.E. and Gross, P., Pulmonary Deposition and Rentention of Inhaled Aerosols, p. 149. Academic Press, New York, New York, 1964, (2) Interim Guide for Respirable Masa Sampling, AIHA Aerosol Techno logy Committee, AIHA J. 31, 2, 1970, p. 133. n) This automatically reduces all particulate substances in Adopted List with TLV of 15 mg/M^ to 10 mg/vfl. p) Both concentration and per cent quartz for the application of this limit are to be determined from the fraction passing a size-selector with the following char acteristics : Aerodynamic Diameter (/4 (unit density sphere) :2 2.5 3.5 5.0 10 % passing selector 90 75 50 25 0 18 FMSI 02933 v APPENDIX A Al Because of the high incidence of cancer, either in man or in animals, no exposure or contact by any route, respiratory, oral or skin should be permitted for the compounds: 2-Acetylaminofluorene 4-Aminodiphenyl Benzidine & its salts Dichlorobenzidine 4-Dimethylaminoazobenzene beta-Naphthylamine 4-Nitrodiphenyl N-Nitrosodimethylamine beta-Propiolactone Because of the extremely high incidence of bladder tumors in workers handling beta-naphthylamine and the potential carcinogenic activity of the other compounds, the State of Pennsylvania prohibits the manufacture, use and other activities that involve human exposure without express approval by the Department of Health. A2 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 recom mended pending determination of the toxicity of the products, but air concentrations should be minimal. A3 Gasoline cnd/or Petroleum Distillates. The composi tion 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 con tent will determine what TLV applies. Consequently the content of benzene, other aromatics and additives should be determined to arrive at the appropriate TLV (Elkins, et al. A.I.H.A.J. 24, 99, 1963). * Trade Names: Algoflon, Fluon, Halon, Teflon, Tetran APPENDIX B B.1 THRESHOLD LIMIT VALUES FOR MIXTURES When two or more hazardous substances are present* their combined effect, rather than that of either individually, should be given primary consideration. In the absence of 19 FMSI 02934 TT information to the contrary, the effects of the different hazards should be considered as additive. That is, if the sum of the following fractions, Ci C2 Cn T1 t2 Tn exceeds unity, then the threshold limit of the mixture should be considered as being exceeded. Ci indicates the observed atmospheric concentration, and Ti the corresponding thres hold limit, (See Example lA.a.). Exceptions to the above rule may be made when there is good reason to believe that the chief effects of the different harmful substances are not in fact additive, but independent as when purely local effects on different organs of the body are produced by the various components of the mixture. In such cases the threshold limit ordinarily is exceeded only when at least one member of the series/C1 Qr c2 etc.l 'T1 r+TjT ' itself has a value exceeding unity, (See Example lA.b.). Antagonistic action or potentiation may occur with some combinations of atmospheric contaminants. Such cases at present must be determined individually. Potentiating or antagonistic agents are not necessarily harmful by them selves. 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 exhibited at high con centrations, less probably at low. When a given operation or process characteristically emits a number of harmful dusts, fumes, vapors or gases, it will frequently be only feasible to attempt to evaluate the hazard by measurement of a single substance. In such cases, the threshold limit used for this substance should be reduced by a suitable factor, the magnitude of which will depend on the number, toxicity and relative quantity of the other contaminants ordinarily present. Examples of processes which are typically associated with two or more harmful atmospheric contaminants are welding, automobile repair, blasting, painting, lacquering, certain foundry operations, diesel exhausts, etc., (Example 2.) 20 FMSI 02935 THRESHOLD LIMIT VALUES FOR MIXTURES EXAMPLES 1A. General case, where air is analyzed for each component a. Additive effects, (note: It is essential that the atmosphere be analyzed both qualitatively and quantitatively for each component present, in order to evaluate compliance or noncompliance with this calculated TLV.) Cl C2 Tl T2 =1 Example No. 1: Air contains 5 ppm of carbon tetrachloride (TLV = 10 ppm) 20 ppm of ethylene dich loride (TLV = 50 ppm) and 10 ppm of ethylene dibromide (TLV = 25 ppm) Atmospheric concentration of mixture = 5 + 20 + 10 = 35 ppm of mixture 5 20 10 25 +20 + 20 10 +50+ 25 ~ 50 " 1,3 Threshold Limit is exceeded. Furthermore, the TLV of this mixture may be calculated by reducing the total fraction to 1.0; i.e. TLV of mixture = ^3 = 27 ppm Example No. 2: Air contains 200 ppm of hexane (TLV = 500 ppm) 100 ppm of methylene chloride (TLV = 500 ppm) and 20 ppm of perchlorethylene (TLV =100 ppm) Atmospheric concentration of mixture = 200 + 100 + 20 = 320 ppm of mixture 200 100 20 200 + 100 + 100 400 ,, ,, 500 + 500 + 100 ~ 500 = WS " 8 Threshold Limit is not exceeded. The TLV of this mixture 320 ... = 078 = 400 ppm 21 FMSI02936 IB, Special case when the source of contaminant is a liquid mixture and the atmospheric composition is assumed to be similar to that of the original material; e.g. on a time weighted average exposure basis, all of the liquid (solvent) mixture eventually evaporates. a. Additive effects (approximate solution) 1. The percent composition (by weight) of the liquid mixture is known, the TLVs of the constituents must be listed in mg/M3. (NOTE: In order to evaluate compliance with this TLV, field sampling instruments should be calibrated, in the laboratory, for response to this specific quantitative and qualitative air-vapor mixture, and also to fractional con centrations of this mixture; e.g,, 1/2 the TLV; 1/10 the TLV; 2 X the TLV; 10 X the TLV; etc.) TLV of mixture = --;-----------^j---------- fa fb fc TLVa + TLVb + TLVC + TLVn Example No. 1: Liquid solvent contains (by weight) 50% heptane (TLV = 2000 mg/M3) 30% methylene chloride (TLV = 1740 mg/M3) 20% perchlorethylene (TLV = 670 mg/M3) TLV of mixture = -p-g Q;3~q72 = .00025+. 00017+.0003 2000+1740+670 = = 1390 m6/M3 Of this mixture: 50% or 695 mg/M3 is heptane, 30% or 417 mg/M3 is methylene chloride and 20% or 278 mg/M3 is perchlorethylene These values can be converted to ppm as follows: heptane: 2000 mg/M3 = 500 ppm 1 mg/M3 = 0.25 ppm 695 mg/M3 = 174 ppm methylene chloride: 1740 mg/M3 = 500 ppm 1 mg/M3 = 0.287 ppm 417 mg/M3 = 119 ppm 22 FMSI 02937 perchlorethylene: 670 mg/M3 = 100 ppm 1 mg/M3 = 0.15 ppm 278 mg/M3 = 42 ppm The TLV of this mixture = 174 + 119 + 42 = 335 ppm. lB.b. General Exact Solution for Mixtures of N Components With Additive Effects and Different Vapor Pressures. (1) Cl C2 Cn _ , Ti + T2 +........ + Tn ' ' (2) Cl + C2 +......... + Cn = T; (2.1)CI+C1+ . Cn_, By the Law of Partial Pressures, (3) Ci = api, and by Raoult's Law, (4) Px = FiPi- Combine (3) and (4) to obtain (5) Ci=aFlPl. Combining (1), (2,1) and (5), we obtain (6) FlPl f2P2 ip FnPn rj " FlPl f2P2 FnPn +....... + and solving for T, (6.1) FiPi * f2P2 +......... + FnPn T= FlPl f2P2 FnPn Tl + T2 +........ + Tn or = n F^0 (6-2) T i = 1 1 i=n i1 1! Tl 23 FMSI 02938 T = Threshold Limit Value in ppm. C = Vapor concentration in ppm. p = Vapor pressure of component in solution. p = Vapor pressure of pure component. F = Mol fraction of component in solution, a = A constant of proportionality. Subscripts 1, 2, ... n relate the above quantities to components 1, 2, ... n, respectively. Subscript i refers to an arbitrary component from 1 to n. Absence of subscript relates the quantity to the mix ture. IB. c. Solution to be applied when there is a reservoir of the solvent mixture whose composition does not change appreciably by evaporation. Exact Arithmetic Solution of Specific Mixture Mol. Density TLV pat wt. 25C Mol fraction in half-and- half solution by volume Trichloro ethylene (1) 131.4 1.46g/ml 100 73mm Hg Methylchloroform (2) 133.42 1.33g/ml 350 125mmHg FfPi0 = (0.527) (73) = 38.2 F2p2 = (0.473) (125) = 59.2 0.527 0.473 T1V 38,2 + 59.2 _ (97.4) (350) (97.4) (350) _ m " 38,2 59.2 ' 133.8 + 59.2 " 193.0 "W + "350" TLV = 177 ppm (Note difference in TLV when account is taken of vapor pressure and mol fraction in comparison with above sample where such account is not taken.) 2. A mixture of one part of (1) parathion (TLV, 0.1) and two parts of (2) EPN (TLV, 0.5). C1 , c2 _ cm 0.1 0.5 ' Tm C2 = 2Cj 24 FMSI 02939 cm _ 3^i Cl 2Ci 3Ci 0.1 + 0.5 = Tm 7Cj 3Cj ox = 'r^r Tm = --- = 0.21 mg/ 1C. TLV for Mixtures of Mineral Dusts. For mixtures of biologically active mineral dusts the general formula for mixtures may be used. For a mixture containing 80% talc and 20% quartz, the TLV for 100% of the mixture is given by: TLV =----------------- =8.4 mppcf 0.8 0.2 20 + 2.5 Essentially the same result will be obtained if the limit of the more (most) toxic component is used provided the effects are additive. In the above example the limit for 20% quartz is 10 mppcf. For another mixture of 25% quartz, 25% amorphous silica and 50% talc: TLV = -------------- ---------------- =7.3 mppcf 0.25 0.25 0.5 2.5 +20+20 The limit for 25% quartz approximates 8 mppcf. 25 TT FMSI 02940 APPENDIX C PERMISSIBLE EXCURSIONS FOR TIME-WEIGHTED AVERAGE (TWA) LIMITS The Excursion TLV Factor in the Table automatically de fines the magnitude of the permissible excursion above the limit for those substances not given a "C" designation; i.e., the TWA limits. Examples in the Table show that nitroben zene, the TLV for which is 1 ppm, should never be allowed to exceed 3 ppm. Similarly, carbon tetrachloride, TLV 10 ppm, should never be allowed to exceed 20 ppm. By contrast, those substances with a "C" designation are not subject to the excursion factor and must be kept below the TLV. These limiting excursions are to be considered to provide a 'rule-of-thumb' guidance for listed substances generally, and may not provide the most appropriate excursion for a particular substance. Efforts are being made to develop such specific excursions, when indicated to be significantly dif ferent from that recommended by the present excursion fac tors. Substance TLV Excursion Factor Max. Cone. Permitted for short time Nitrobenzene Carbon tetrachloride Carbon monoxide Acetone Boron trifluoride Butylamine Styrene monomer 1 ppm 10 ppm 50 ppm 1000 ppm C 1 ppm C 5 ppm C 100 ppm 3 2 1.5 1.25 - 3 ppm 20 ppm 75 ppm 1250 ppm 1 ppm 5 ppm 100 ppm For all substances: TLV = 0-1 (ppm or mg/m^), Excursion Factor TLV = 1-10 " "" TLV = 10-100 " "" TLV = 100 - 1000 " "" =3 =2 =1.5 =1.25 BASIS FOR ASSIGNING LIMITING "C" VALUES By definition in the Preface, a listed value bearing a "C" designation refers to a 'ceiling' value that should not be exceeded; all values should fluctuate below the listed value. This, in effect, makes the "C" designation a maximal allow able concentration (MAC). In general, the bases for assign- 26 FMSI 02941 ing or not assigning a "C" value rest on whether excursions of concentration above a proposed limit for periods up to 15 minutes may result in a) intolerable irritation, b) chronic, or irreversible tissue change, or c) narcosis of sufficient degree to increase accident proneness, impair self-rescue or materially reduce work efficiency. APPENDIX D Some "Inert" or Nuisance Particulates *ll Alundum (AI2O3) Calcium carbonate Cellulose (paper fiber) Portland Cement Corundum (AI2O3) Emery Glycerine Mist Graphite (synthetic) Gypsum Vegetable oil mists (except castor, cashew nut, or similar irritant oils) Kaolin Limestone Magnesite Marble Pentaerythritol Plaster of Paris Rouge Silicon Carbide Starch Sucrose Tin Oxide Titanium Dioxide q) When toxic impurities are not present, e. g. quartz < 1%. APPENDIX E Some Simple Asphyxiants - "Inert" Gases and Vapors Acetylene Argon Ethane Ethylene Helium Hydrogen Methane Neon Nitrogen Nitrous Oxide Propane 1970 TLV COMMITTEE MEMBERS Paul E. Caplan Hervey B. Elkins, Ph. D. W. G. Fredrick, Sc. D. Bernard Grabois, P. E. Paul Gross, M. D. Wayland J. Hayes, Jr., M. D. John W. Knauber Harold N. MacFarland, Ph. D. Frederick T. McDermott E. Mastromatteo, M. D. Col. WalterW. Melvin, Jr.,M.D. Ralph G. Smith, Ph. D. Mitchell R. Zavon, M. D. Herbert E. Stokinger, Ph. D., Chairman William D. Wagner, Recording Sec'y 27 FMSI 02942