Document YG6JkRew72JwLjEMgaoJp3aKk

Threshold Limit Values for Chemical Substances and Physical Agents in the Workroom Environment with Intended Changes for 1979 511904 0131 Copyright 1979 by American Conference of Govern mental Industrial Hygienists. This book is fully protected by copyright and no part of it may be reproduced in any form, by print, photo print, microfilm, or any other means without written per mission from the American Conference of Governmental Industrial Hygienists, P.O. Box 1937, Cincinnati, Ohio 45201. PRICE EACH 1-49................................................................. $2.00 50-199............................................................. 1.75 200-999........................................................... 1.50 1000-4999....................................................... 1.25 5000 or more.................................................... 1.00 Documentation of the Threshold Limit Values for Sub stances in Workroom Air.9 A separate companion piece to the Chemical TLVs is issued by ACGIH 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 con tains 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 Docu mentation be consulted when the TLVs are being used. Information concerning the availability of copies of the Documentation of the Threshold Limit Values for Substances in Workroom Air should be directed to the Publications Office, ACGIH (third edition, fourth printing, 1978, $20.00). TLVs Threshold Limit Values for Chemical Substances in Workroom Air Adopted by ACGIH for 1979 511904 0132 1979 TLV AIRBORNE CONTAMINANTS COMMITTEE Hervey B. Elkins, Ph.D., Retired, Chairman Charles E. Adkins, OSHA Mary 0. Amdur, Ph.D., Massachusetts Institute of Tech nology Hector P. Blejer, M.D., Honorary Paul E. Caplan, P.E., M.P.H., NIOSH James W. Hammond, University of Texas John W. Knauber, M.P.H., Pennsylvania Dept, of Envi ronmental Resources Jesse Lieberman, P.E., USN Trent R. Lewis, Ph.D., NIOSH Keith R. Long, Ph.D., University of Iowa Frederick T. McDermott, Michigan Dept, of Public Health Floyd A. Madsen, OSHA Walter W. Melvin, Jr., M.D., Sc.D., Colorado State Uni versity Leonard 0. Pagnotto, Massachusetts Dept, of Labor & Industry, Secretary Ronald S. Ratney, OSHA Meier Schneider, P.E., C.I.H., City of Los Angeles Richard D. Stewart, M.O., Medical College of Wisconsin Vera F. Thomas, Ph.D., University of Miami William D. Wagner, NIOSH Elizabeth K. Weisburger, Ph.D., National Cancer Insti tute CONSULTANTS Paul Gross, M.D. E. Mastromatteo, M.D. James F. Morgan Marshall Steinberg, Ph. D. Theodore R. Torkelson, Sc.D. Ralph C. Wands Mitchell R. Zavon, M.D. Any comments or questions regarding these limits should be addressed to: Executive Secretary American Conference of Governmental Industrial Hygienists P.O. Box 1937 Cincinnati OH 45201: (513) 941-0178 TABLE OF CONTENTS Chemical Substances Page Preface............................................................... Threshold Limit Values and Short Term Exposure Limits............................................................ Radioactivity...................................................... Mineral Dusts............................................ Nuisance Particulates.......................................... Notice of Intended Changes.................................. Appendices A. Carcinogens.............................................. 8. Substances of Variable Composition........... C. Mixtures: Calculation of TLVs..................... D. Excursions Time-Weighted Average......................... Peak Concentrations.............................. E. Nuisance Particulates................................ F. Asphyxiants.............................................. G. Conversion of Particle Count to Mass.......... 2 9 31 32 33 34 38 45 46 50 51 52 52 52 Physical Agents Preface............................................................... Threshold Limit Values Heat Stress..................................................... Ionizing Radiation........................................... Lasers............................................................ Microwaves.................................................... Noise.............................................................. Impulsive or Impact Noise............................... Ultraviolet Radiation......................................... Notice of Intended Changes.................................. Notice of Intent: Light and Near-Infrared Radiation...................... Airborne Upper Sonic and Acoustic Radiation..... Agents Under Study......................................... 57 58 67 67 82 83 84 86 89 90 93 94 1 511904 PREFACE CHEMICAL CONTAMINANTS Threshold limit values refer to airborne concentra tions of substances and represent conditions under which it is believed that nearly all workers may be re peatedly exposed day after day without adverse ef fect Because of wide variation in individual suscepti bility, however, a small percentage of workers may experience discomfort from some substances at con centrations at or below the threshold limit; a smaller percentage may be affected more seriously by aggra vation of a pre-existing condition or by development of an occupational illness. Tests are available (J. Occup. Med. IS: 564, 1973; Ann. N.Y. Acad. Sci., 151, Art. 2: 968, 1968) that may be used to detect those individuals hypersusceptible to a variety of industrial chemicals (respiratory irri tants, hemolytic chemicals, organic isocyanates, car bon disulfide). Three categories of Threshold Limit Values (TLVs) are specified herein, as follows: a) Threshold Limit Value-Time Weighted Average (TLV-TWA) -- the time-weighted average concentra tion for a normal 8-hour workday or 40-hour work week, to which nearly all workers may be repeatedly exposed, day after day, without adverse effect b) Threshold Limit Value-Short Term Exposure Limit (TLV-STEL) -- the maximal concentration to which workers can be exposed for a period up to 15 minutes continuously without suffering from 1) irrita tion, 2) chronic or irreversible tissue change, or 3) narcosis of sufficient degree to increase accident proneness, impair self-rescue, or materially reduce work efficiency, provided that no more than four ex cursions per day are permitted, with at least 60 min utes between exposure periods, and provided that the daily TLV-TWA also is not exceeded. The STEL should be considered a maximal allowable concentra tion. or ceiling, not to be exceeded at any time during the 15-minute excursion period. STELs are based on one or more of the following criteria: (1) Adopted TLVs including those with a "C" or "ceiling" limit. (2) TWA-TLV Excursion Factors listed in Appendix 0. (3) Pennsylvania Short-Term Limits for Exposure to Air borne Contaminants (Penna. Dept, of Hlth., Chapter 4, 2 Art. 432, Rev. Jan. 25, 1968). (4) OSHA Occupational Safety and Health Standards. 40 FR 23073, May 28, 1975. (5) NIOSH criteria for recommended standards for occupational exposure to specific substances. The TWA-STEL should not be used as engineering design criterion or considered as an emergency expo sure level (EEL). c) Threshold Limit Value-Ceiling (TLV-C) --the concentration that should not be exceeded even in stantaneously. For some substances, e.g., irritant gases, only one category, the TLV-Ceiling, may be relevant. For other substances, either two or three categories may be rel evant, depending upon their physiologic action. It is important to observe that if any one of these three TLVs is exceeded, a potential hazard from that sub stance is presumed to exist. The TLV-TWA should be used as guides in the control of health hazards and should not be used as fine lines between safe and dangerous concentra tions. Time-weighted averages permit excursions above the limit provided they are compensated by equiva lent excursions 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 re lated to the magnitude of the threshold limit value of a particular substance as given in Appendix D. 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 concentra tions-- even for short periods --produce acute poi soning, whether the effects are cumulative, the fre quency with which high concentrations occur, and the duration of such periods. All-factors must be taken into consideration in arriving at a decision as to whether a hazardous condition exists. Threshold limits are based on the best available information from industrial experience, from experi mental human and animal studies, and. when possi ble, from a combination of the three. The basis on which the values are established may differ from sub stance to substance; protection against impairment of health may be a guiding factor for some, whereas reasonable freedom from irritation, narcosis, nui sance or other forms of stress may form the basis for others. 3 511904 0134 The amount and nature of the information avail able for establishing a TLV varies from substance to substance; consequently, the precision of the esti mated TLV is also subject to variation and the latest Documentation should be consulted in order to assess the extent of the data available for a given sub stance. 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. There is increasing evidence that physical irri tation may initiate, promote or accelerate physical im pairment through interaction with other chemical or biologic agents. In spite of the fact that serious injury is not be lieved likely as a result of exposure to the threshold limit concentrations, 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 industrial hygiene and should be interpreted and ap plied 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 nui sances. (3) in estimating the toxic potential of contin uous, uninterrupted exposures or other extended work periods, (4) as proof or disproof of an existing disease or physical condition, 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. Al though the time-weighted average concentration pro vides the most satisfactory, practical way of monitor ing airborne agents for compliance with the limits, there are certain substances for which it is inappro priate. In the latter group are substances which are predominantly fast acting and whose threshold limit is more appropriately based on this particular re sponse. 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 noncompliance 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 suffi cient number of samples are needed to permit a timeweighted average concentration throughout a com plete cycle of operations or throughout the work shift. 4 Whereas the ceiling limit places a definite bounda ry which concentrations should not be permitted to exceed, the time-weighted average limit requires an explicit limit to the excursions that are permissible above the listed values. The magnitude of these ex cursions may be pegged to the magnitude of the threshold limit by an appropriate factor shown in Ap pendix D. It should be noted that the same-factors are used by the Committee in determining the magnitude of the value of the STELs, or whether to include or exclude a substance for a "C" listing. "Skin" Notation. Listed substances followed by the designation "Skin" refer to the potential contribu tion to the overall exposure by the cutaneous route including mucous membranes and eye, either by air borne, or more particularly, by direct contact with the substance. Vehicles can alter skin absorption. This at tention-calling designation is intended to suggest ap propriate measures for the prevention of cutaneous absorption so that the threshold limit is not invalid ated. Mixtures. Special consideration should be given also to the application of the TLVs in assessing the health hazards which may be associated with expo sure to mixtures of two or more substances. A brief discussion of basic considerations involved in devel oping threshold limit values for mixtures, and meth ods for their development, amplified by specific ex amples are given in Appendix C. Nuisance Particulates. In contrast to fibrogenic dusts which cause scar tissue to be formed in lungs when inhaled in excessive amounts, so-called "nui sance" dusts have a long history of little adverse ef fect 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. Howev er, the lung-tissue reaction caused by inhalation of nuisance dusts has the following 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 reversible. Excessive concentrations of nuisance dusts in the workroom air may seriously reduce visibility, may cause unpleasant deposits in the eyes, ears and nasal passages (Portland Cement dust), or cause injury to the skin or mucous membranes by chemical or ms- 5 511904 0135 chanical action per se or by the rigorous skin cleans ing procedures necessary for their removal. A threshold limit of 10 mg/m3, or 30 mppcf, of total dust < 1% quartz, or, 5 mg/m3 respirable dust is rec ommended for substances in these categories and for which no specific threshold limits have been as signed. This limit for a normal workday, does not apply to brief exposures at higher concentrations. Neither does it apply to those substances which may cause physiologic impairment at lower concentra tions but for which a threshold limit has not yet been adopted. Some nuisance particulates are given in Ap pendix E. Simple Asphyxiants -- "Inert" Gases or Vapors. A number of gases and vapors, when present in high concentrations in air, act primarily as simple asphyx iants without other significant physiologic effects. A TLV may not be recommended for each simple as phyxiant because the limiting factor is the available oxygen. The minimal oxygen content should be 18 percent by volume under normal atmospheric pres sure (equivalent to a partial pressure, p02 of 135 mm Hg). Atmospheres deficient in 02 do not provide ade quate warning and most simple asphyxiants are odorless. Several simple asphyxiants present an ex plosion hazard. Account should be taken of this fac tor in limiting the concentration of the asphyxiant. Specific examples are listed in Appendix F. Physical Factors. It is recognized that such physi cal factors as heat, ultraviolet and ionizing radiation, humidity, abnormal pressure (altitude) and the like may place added stress on the body so that the ef fects from exposure at a threshold limit may be al tered. 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 sub stances are not of such a magnitude as to take care of gross deviations. For example, continuous work at temperatures above 90F, or overtime extending the workweek more than 25%, might be considered gross deviations. In such instances judgment must be exer cised in the proper adjustments of the Threshold Limit Values. Biologic Limit Values (BLVs). Other means exist and may be necessary for monitoring worker expo sure other than reliance on the Threshold Limit Val ues for industrial air, namely, the Biologic Limit Val ues. These values represent limiting amounts of 6 substances (or their effects) to which the worker may be exposed without hazard to health or well-being as determined in his tissues and fluids or in his exhaled breath. The biologic measurements on which the BLVs are based can furnish two kinds of information useful in the control of worker exposure: (1) measure of the individual worker's over-all exposure: (2) mea sure of the worker's individual and characteristic re sponse. Measurements of response furnish a superior estimate of the physiologic status of the worker, and may be made of (a) changes in amount of some criti cal biochemical constituent, (b) changes in activity of a critical enzyme, (c) changes in some physiologic function. Measurement of exposure may be made by (1) determining in blood, urine, hair, nails, in body tis sues and fluids, the amount of substance to which the worker was exposed: (2) determination of the amount of the metabolite(s) of the substance in tissues and fluids; (3) determination of the amount of the sub stance in the exhaled breath. The biologic limits may be used as an adjunct to the TLVs for air, or in place of them. The BLVs, and their associated procedures for determining compliance with them, should thus be regarded as an effective means of providing health surveillance of the worker. Unlisted Substances. Many substances present or handled in industrial processes do not appear on the TLV list. In a number of instances the material is rare ly present as a particulate, vapor or other airborne contaminant, and a TLV is not necessary. In other cases sufficient information to warrant development of a TLV, even on a tentative basis, is not available to the Committee. Other substances, of low toxicity, could be included in Appendix E pertaining to nui sance particulates. This list (as well as Appendix F) is not meant to be all inclusive; the substances serve only as examples. In addition there are some substances of not in considerable toxicity, which have been omitted pri marily because only a limited number of workers (e.g., employees of a single plant) are known to have potential exposure to possibly harmful concentra tions. "Notice ot Intent." At the beginning of each year, proposed actions of the Committee for the forthcom ing year are issued in the form of a "Notice of Intend ed Changes." This Notice provides not only an oppor tunity for comment, but solicits suggestions of substances to be added to the list. The suggestions should be accompanied by substantiating evidence. 7 511904 The list of Intended Changes follows the Adopted Val ues in the TLV booklet. Values listed in parenthesis in the "Adopted" list are to be used during the period in which a proposed change for that Value is listed in the Notice of Intended Changes. Legal Status. The Threshold Limit Values, as is sued by ACGIH. are recommendations and should be used as guidelines for good practices. Wherever these values (of whatever year) have been used or in cluded by reference in Federal and/or State statutes and registers, the TLVs do have the force and effects of law. Reprint Permission. This book is fully protected by copyright and no part of it may be reproduced in any form, by print, photoprint, microfilm or any other means without written permission from the American Conference of Governmental Industrial Hygienists. Inc., P.O. Box 1937, Cincinnati, OH 4S201. 8 A00PTE0 VALUES TENTATIVE VALUES Substance TWA STEL ppm"' mg/m1'1 ppm"1 mg/m*' Abate....................... _ Acetaldehyde.............. Acetic acid................. 100 10 C Acetic anhydride.......... 5 " Acetone .................... (1,000) Acetonitrile................. 40 Acetylene................... F Acetylene dichloride, see 10 180 150 25 15 20 (2,400) (1.250) 70 60 -- 20 270 37 (3,000) 105 1,2-Dichloroethylene . Acetylene tetrabromide... Acrolein.................... Aciylamide -- Skin...... " Acrylonitrile -- Skin..... Aldrin -- Skin............. Ally! alcohol -- Skin.... Allyl chloride............... Ally! glycidyl ether (AGE) --Skin.......... Allyl propyl disulfide..... * Aluminum metal and oxide..................... Aluminum pyro powders. Aluminum welding fumes Aluminum, soluble salts. * Aluminum, alkyls (NOC)* Alundum*.................. 4-Aminodi phenyl -- Skin 2-Aminoethanol, see Ethanolamine........... 2-Aminopyridine.......... 3-Amino 1, 2, 4-triazole. Ammonia........... Ammonium 200 1 0.1 -- (20) -- 2 1 5 2 _ _ -- _ _ -- -- 3 0.5 A2 25 790 250 1,000 15 1.5 20 0.25 0.3 0.8 0.3 0.6 (45) (30) (65) 0.25 0.75 54 10 32 6 22 10 12 3 44 18 10 5 5 2 _ _ _ _ 20 _ _ 2 E _ 20 Alb -- Alb a6 22 A2 18 35 15 4 27 chloride-fume.......... Ammonium sulfamate (Ammate)............... n-Amyl acetate............ sec-Amyl acetate.......... " Aniline -- Skin............ Anisidine (o-. -- _ 100 125 (5) 10 -- 10 _ 530 150 670 150 (19) -- 20 20 800 800 p-isomers) --Skin.... 0.1 0.5 Capital letters refer to Appendices. Footnotes {a thru f) see Page 31 "See Notices of intended Changes. *1979 Addition 9 511904 0137 Substance ADOPTED TENTATIVE VAIUES_________ VALUES TWA STEL ppm*1 mg/m1*1 ppm*> mg/m1*1 '" Antimony & Compounds (as Sb).................. -- (0.5) -- -- Antimony trioxide. handling and use (as Sb)........................ -- 0.5 -- _ ** Antimony trioxide production (asSb).... -- (0.5, A2) -- -- ANTU (a-Naphthyl thiourea) ................ -- 0.3 -- 0.9 Argon....................... F -- F F "Arsenic & compounds (as As) .................. -- (0.5) -- -- " Arsenic trioxide production (as As).... -- (Ala) -- -- Arsine...................... 0.05 0.2 -- -- "Asbestos (allforms)..... -- (Ala) -- (Ala) Asphalt (petroleum) fumes.................... -- 5-- 10 Atrazine.................... -- 10 -- -- Azinphos-methyl -- Skin -- 0.2 -- 0.6 Barium (soluble compounds), as Ba.... Baygon (propoxur)...... -- -- 0.5 -- 0.5 -- _ 2 * Benomyi.................... 0.8 10 1.3 15 Benzene .................... 10, A2 30. A2 -- -- Benzidine production --Skin.... -- Alb _ Alb p-Benzoqumone, see Quinon'e................. Benzoyl peroxide.......... 0.1 -- 0.4 0.3 5-- 2 -- Benzo(ajpyrene ........... -- A2 -- A2 Benzyl chloride............ 1 5-- -- Beryllium................... -- 0.002, A2 -- -- Biphenyl.................... 0.2 1.5 0.6 4 Bismuth telluride.......... -- 10 -- 20 Bismuth tellunde. Se-doped................ -- 5-- 1C Borates, tetra. sodium salts. Anhydrous .............. -- 1-- -- Decahydrate............ -- 5-- -- Capital letters refer to Appendices. Footnotes (a thru f) see Page 31 "See Notice of Intended Changes '1979 Addition 10 Substance Pentahydrate........... Boron oxide................ Boron tribromide.......... C Boron tnfluoride.......... * Bromacil................... Bromine.................... Bromine pentafluoride.... Bromochloromethane/ chlorobromomethane . Bromoform -- Skin..... Butadiene (1, 3-butadiene)............ " Butane....................... Butanethiol, see Butyl mercaptan.............. 2-Butanone................ " 2-Butoxyethanol (Butyl Cellosolve) -- Skin.... n-Butyl acetate............ sec-Butyl acetate.......... tert-Butyl acetate.......... Butyl acrylate.............. C n-Butyl alcohol -- Skin.. " sec-Butyl alcohol......... tert-Butyl alcohol.......... C Butylamine -- Skin...... C tert-Butyl chromate (as CrOs) -- Skin.......... " n-Butyl glycidyl ether (BGE).................... n-Butyl lactate............. Butyl mercaptan........... p-tert-Butyltoluene....... Cadmium, dust & salts (as Cd).................. C Cadmium oxide fume (as Cd)........................ " Cadmium oxide production (as Cd).... Calcium carbonate/ marble.................. Calcium arsenate (as As) CapHal letters refer to Appendices. *1979 Addition "See Notice of Intended Changes. ADOPTEO VALUES TWA ppm*' mg/m1*' 1 _ 10 1 10 13 1 10 0.1 0.7 0.1 0.7 200 1,050 0.5 5 1.000 2,200 (600) (1.430) 0.5 1.5 200 590 (50) (240) 150 710 200 950 200 950 10 55 50 150 (150) (450) 100 300 5 15 _ 0.1 (50) (270) 5 25 0.5 1.5 10 60 _ 0.05 -- 0.05 _ (A2) -- _ E 1 TENTATIVE VALUES STEL ppm*1 mg/m1*' __ 20 3 30 2 20 0.3 2 0.3 2 250 1,300 1.250 (750) __ 300 (150) 200 250 250 _ -- 150 2.750 (1.780) _ 885 (720) 950 1.190 1,190 _ 450 _ __ _ __ __ 20 120 0.2 __ __ _ _ 20 11 511904 0138 Substance Calcium cyanamide...... Calcium hydroxide....... Calcium oxide............. Camphor, synthetic...... Caprolactam Oust..................... Vapor.................... Captafol (Difolatan) -- Skin... Captan....................... Carbaryl (Sevin*)........ Carbofuian (Furadan).. Carbon black.............. Carbon dioxide............ " Carbon disulfide -- Skin Carbon monoxide......... Carbon tetrabromide.... ** Carbon tetrachloride -- Skin.. Carbonyl chloride (Phosgene)............. ** Carbonyl fluoride.......... Catechol (Pyrocatechol).. Cellulose (paperfiber).... Cesium hydroxide........ Chlordane -- Skin....... Chlorinated camphene -- Skin.... Chlorinated diphenyl oxide..................... Chlorine.................... Chlorine dioxide........... C Chlorine trifluoride....... C Chloroacetaldehyde...... a-Chloroacetophenone (Phenacyl chloride).... Chlorobenzene (Monochlorobenzene). o-Chlorobenzylidene malonoitrile -- Skin... Chlorobromomethane/ Bromochloromethane . ADOPTED VALUES TWA ppm> 0.5 _ _ 5 2 2 12 TENTATIVE VALUES STEL ppm-1 _ --_ 1 _ 3 18 13 5 20 10 40 -- -- -- -- _ 5,000 (20) 50 0.1 0.1 -- 5-- 5-- 0.1 _ 3.5 _ 9.000 15,000 (60) (30) 55 400 1.4 0.3 -- 15 10 _ 7 18.000 (90) 440 4 (10) (65) (20) (130) 0.1 0.4 _ (5) (15) _ 5 20 -- -- E -- - -- -- 2 0.5 _ _ _ _ -- 20 _ 2 -- 0.5 _ 1 _ 0.5 _ 2 1 33 9 0.1 0.1 1 0.3 0.4 0_.3 3_ 0_.9 _ 0.05 0.3 _ _ 75 350 -- 0.05 0.4 _ -- _ 200 1,050 250 1,300 Capital letters refer to Appendices. *'$ee Notice of Intended Changes. 12 Substance 2-Chloro-1,3-butadiene, see Chloroprene -- Skin...................... Chlorodifluoromethane. Chlorodiphenyl (42% Chlorine) -- Skin..... Chlorodiphenyl (54% Chlorine) -- Skin..... 1-Chloro, 2, 3-epoxy-propane (Epichlorttydrin) -- Skin....................... C 2-Chloroethanol (Ethylene chlorohydrin) -- Skin. " Chloroethylene (Vinyl chloride)................ Chloroform (Trichloromethane).... bis-Chloromethyl ether... " 1-Chloro-l-nitropropane. .Chloropicrin............... * 0-Chloroprene -- Skin .. Chlorpyrifos (Oursban*) -- Skin... o-Chlorostyrene........... o-Chlorotoiuene -- Skin. 2-Chloro- 6-(trichloromettyl pyridine (N-Serve*)... " Chromates, certain insoluble forms....... ' Chromic acid and Chromates, (as Cr).... Chromite ore processing (chromate), as Cr..... Chromium, Sol. chromic, chromous salts (as Cr)............ Clopidol (Coyden*)..... Coal tar pitch volatiles ADOPTEO VALUES TWA ppm'" mg/mJ 25 90 1,000 3,500 --1 -- 0.5 5 20 1 (Ale) 10, A2 0.001 (20) 0.1 (25) -- 50 50 3 -- 50, A2 Ala (100) 0.7 (90) 0.2 285 250 -- 10 -- (0.05,Ala) -- (0.05) -- 0.05, Ala -- 0.5 -- 10 TENTATIVE VALUES STEL ppm'" mg/m1 35 125 1,250 4,375 --2 --1 10 40 __ (Ale) _ --_ _ Ala ---- 0.3 2 (35) (135) -- 0.6 75 430 75 375 _ 20 -- (Ala) ---- ---- ---- -- 20 Capital letters refer to Appendices. Footnotes (a thru f) see Page 3t. "See Notice ot Intended Changes. 13 511904 0139 Substance (See Particulate polycyclic aromatic hydrocarbons)......... * Cobalt metal, dust and lume (as Co)........... Copper fume............... Ousts & Mists (as Cu) Corundum (AIjOj)......... Cotton dust, raw......... Crag herbicide........... Cresol, all isomers -- Skin...... Crotonaldehyde........... Crufornate................ Cumene -- Skin......... Cyanamide................. Cyanides, as CN -- Skin Cyanogen .................. Cyclohexane............... Cyclohexanol.............. ' Cyclohexanone............ Cyclohexene............... Cyclohexylamine -- Skin Cyclopentadiene........... 2. 4-0 (2, 4-Diphenoxy- acetic acid)............. DDT (Dichlorodiphenyltrichloroethane)....... DOVP, see Dichlorvos -- Skin...................... Decaborane -- Skin..... Demeton* -- Skin...... Diacetone alcohol (4-hydroxy-4-methyl2-pentanone)........... 1. 2-Diaminoethane, see Ethylenediamine....... Oiazinon -- Skin......... Oiazomethane............. Diborane................... ADOPTED VALUES TWA ppm"' mg/m*41 0.2,Ala (0.1) -- 0.2 --1 --E -- 0.2*' -- 10 5 22 26 _5 50 245 -- _ 2 5 10 20 300 1,050 50 200 (50) (200) 300 1,015 10 40 75 200 10 1 0.1 1 0.05 0.3 0.01 0.1 50 240 10 _ 25 0.1 0.2 0.4 0.1 0.1 TENTATIVE VALUES STEL ppm*1 mg/m3*' Ala __ _2 _E _ 0.6 20 _6 18 20 75 365 _ __ 3_75 1,3_00 _ __ __ 150 400 20 3 0.3 3 0.15 0.9 0.03 0.3 75 360 _ 0.3 -- __ Capita! letters refer to Appendices. "See Notice of Intended Changes k| Seep. 33. 14 ADOPTED VALUES TWA Substanceppm"1 mg/m341 " 1.2-Dibromoethane (Ethylene dibromide) -- Skin.................. Dibrom................... 2-n-Dibutylaminoethanol (20) -- -- Skin.................. 2 Dibutyl phosphate....... Dibutyl phthalate.......... 1 -- C Dichloracetylene.......... 0.1 C o-Oichlorobenzene....... 50 p-Dichlorobenzene....... OlchlorobenzkJine -- 75 Skin...................... -- Dichlorodifluoromethane. 1,000 1,3-Dichloro-5, 5-dimethyl hydantoin.. -- 1,1-Dichloroethane..... 200 ** 1, 2-Dichloroethane..... 1, 2-Oichloroethylene .... Dichloroethyl ether -- (50) 200 Skin...................... 5 " Dichloromethane, see Methylene chloride .... (200) '* Dichloromonofluoro- methane................. (1.000) C 1,1-Dichloro-1- nitroethane.............. 10 1, 2-Dichloropropane. see Propylene dichloride............... 75 Dichlorotetrafluoro- ethane ................... 1,000 Dichlorvos (DOVP) -- Skin.................. 0.1 Dicrotophos (Bidrin) -- Skin...................... _ Oicyclopentadiene........ Dicyclopentadienyl iron.. 5 -- Dieldrin -- Skin........... _ ** Diethylamine............... Diethylaminoethanol -- (25) Skin....................... 10 (155) 3 14 5 5 0.4 300 450 A2 4,950 0.2 810 (200) 790 30 (700) (4,200) 60 350 7,000 1 0.25 30 10 0.25 (75) 50 TENTATIVE VALUES STEL ppm-1 mg/m3*' (30) 4 2 _ __ 110 _ 1,250 _ 250 (75) 250 10 (250) -- (230) 6 28 10 10 _ 675 A2 6,200 0.4 1,010 (300) 1.000 60 (870) -- -- 110 510 1,250 8,750 0.3 3 __ __ -- 20 0.75 -- apftal letters refer to Appendixes 'See Notice of Intended Changes. 15 511904 0140 Substance ADOPTED VALUES TWA ppm"' mg/m1*' TENTATIVE VALUES STEL ppm" mg/m1*' Diethylene triamine -- Skin...................... 1 Diethyl ether, see Ethyl ether..................... 400 Diethyl phthalate.......... -- Difluorodibromomethane. 100 *C Diglycidyl ether (DGE).... (0.5) Dihydroxybenzene. see Hydroquinone.......... Dirsobutyl ketone......... 25 Diisopropylamine -- Skin...................... 5 Dimethoxymethane, see Methylal................. 1,000 Dimethyl acetamide -- Skin...................... 10 ' Dimethyl carbamyl chloride................. A2 Dimethylamine............ 10 Dimethylaminobenzene, see Xylidene --Skin.. 5 Oimethylaniline (N, N-Dimethylaniline) -- Skin...................... 5 Dimethylbenzene. see Xylene -- Skin........ Dimethyl-1, 100 2-dibromo-2-dichloroethyl phosphate, see Dibrom.................. Dimethylformamide -- Skin...................... 10 2, 6-Dimethyl-4-heptanone, see Diisobutyl ketone.. 25 1. 1-Dimethylhydrazine -- Skin.................. Dimethylphthalate........ 0.5 -- C Dimethyl sulfate -- Skin. 0.1. A2 Dinitrobenzene (all isomers) -- Skin...... 0.15 Dimtro-o-cresol -- Skin . -- 4 1.200 5 860 (3) 2 150 20 3,100 35 A2 18 25 25 435 3 30 150 1 5 0.5, A2 1 0.2 _ 500 -- 150 -- -- 1,250 15 -- 10 10 150 20 1 -- -- 0.5 -- _ 1,500 10 1,2_90 4 3.875 50 _ 50 50 650 6 60 2 10 -- 3 0.6 capital letters reterto Appendices. Footnotes (a ttrnj f)see Page 31 *1979 Addition "See Notice of Intended changes. 16 Substance AOOPTED VALUES TWA ppm*' mg/m1*' TENTATIVE VALUES STEL ppm" mg/m1*' 3. 5-Dinitro-o-toluamide (Zoalene*).............. Oinitrotoluene -- Skin ... Dioxane, tech, grade -- Skin...................... Dioxathion (Oelnav*) -- Skin....................... Diphenyl, see Biphenyl... Diphenylamine............ Diphenylmethane diisocyanate, see Methylene bisphenyl isocyanate (MDI)...... Dipropylene glycol methyl ether -- Skin .. Diquat...................... Di-sec, octyl phthalate (Oi-2-ethylhexylphthalate)............... Disulfiram.................. Disyston -- Skin......... 2, 6-Ditert. butyl-p-cresol.......... Diuron...................... Oyfonate................... Emety...................... Endosultan (Thiodan) -- Skin.................. Endrin -- Skin............ ' Epichlorhydrin -- Skin... EPN -- Skin............... 1. 2-Epoxypropane, see Propylene oxide....... 2. 3-Epoxy-1-propanol, see Glycidol............. Ethane ...................... Ethanethiol. see Ethyl mercaptan.............. Ethanolamine.............. Ethion (Nialate) -- Skin ' 2-Ethoxyethanol -- Skin. 2-Ethoxyethyl acetate (Cellosolve acetate) -- -- -- (50) 0.2 -- 0.02 100 -- -- -- _ -- -- -- -- (5) -- 100 50 F 0.5 3 -- (100) 5-- 1.5 -- (180) __ 0.2 _ 1.5 -0.6 10 -- 0.2 600 150 0.5 -- 5 2-- 0.1 -- 10 _ 10 -- 0.1 -- E-- 0.1 _ 0.1 -- (20) (10) 0.5 -- 240 150 150 75 --F 12 86 0.4 -- (370) (150) 10 5 _ _ 4 20 900 1 10 5 0.3 20 -- -- 20 0.3 0.3 () 2 360 225 -- 3 15 -- (560) Capital letters refer to Appendices "See Notice of Intended Changes. 17 511904 0141 Substance Skin...................... Ethyl acetate............... "Ethyl acrylate --Skin.... Ethyl alcohol (Ethanol)... Ethylamine................. Ethyl amyl ketone (5-Methyl-3heptanone).............. Ethyl benzene.............. Ethyl bromide............. Ethylbutyl ketone (3-Heptanone).......... Ethyl chloride.............. Ethyl ether ................. Ethyl formate.............. Ethyl mercaptan........... ' Ethyl sillicate.............. Ethylene .................... C Ethylene chlorohydrin -- Skin...................... Ethylenediamine........... " Ethylene dibromide, see 1,2-Dibromoethane... " Ethylene dichloride, see 1. 2-Oichloroethane... Ethylene glycol, Particulate.............. " Vapor.................... "C Ethylene glycol dinitrate and/or Nitroglycerin -- Skin.................. Ethylene glycol monomethyl ether acetate (Methyl cellosoive acetate) -- Skin...................... " Ethylene oxide............ Ethylemmme -- Skin.... Ethylidene chloride, see 1, 1-Dichloroethane ... C Ethylidene norbornene ... ADOPTED VALUES TWA ppm01 mg/m1*' (100) 400 (25) 1,000 10 (540) 1,400 (100) 1,900 18 25 130 100 435 200 890 50 230 1,000 2,600 400 1,200 100 300 0.5 1 10 85 F-- 13 10 25 (20) (155) (50) (200) -- 10 (100) (250) (0.2) (2) 25 120 (50) (90) 0.5 1 200 810 5 25 TENTATIVE VALUES STEL ppm"1 mg/mjS' (150) (810) ---- _ " __ 125 545 250 1,110 75 1,250 500 150 2 30 F _ -- (30) 345 3,250 1,500 450 3 255 -- _ -- (230) (75) (300) 20 (125) (325) 35 170 (75) (135) 250 1,010 ---- Capital letters refer to Appendices. Footnotes (a thru I) see Page 31. '1979 Addition "See Notice of Interned Changes 18 ADOPTED VALUES TWA Substanceppm"1 wg/mJ>l n-Ethylmorptioline -- Skin...................... Fensulfothion (Dasanit).. Ferbam..................... Ferrovanadium dust..... Fluoride (as F)............. Fluorine.................... Fluorotrichloromethane .. C Formaldehyde............. Formamide................. Formic acid................ " Furfural -- Skin........... Furfuryl alcohol -- Skin . Gasoline.................... Germanium tetrahydride. Glass, fibrous*' or dust.. 'C Glutaraldehyde............ Glycerin mist.............. " Glycidol (2, 3-Epoxy- 1-propanol)............. Glycol monoethyl ether, see 2-Ethoxyethanol -- Skin.................. Graphite (Synthetic)..... Guthion, see Azinphos-methyl -- Skin....................... Gypsum.................... Hafnium.................... Helium...................... Heptachlor -- Skin...... Heptane (n-Heptane).... Hexachlorocyclopenta- diene..................... Hexachloroethane -- Skin...................... Hexachloronaphthalene -- Skin.................. Hexafluoroacetone....... " Hexane (n-hexane)....... Hexamethyl phosphoramide -- 20 -- -- _ -- 1 1,000 2 20 5 (5) 5 -- 0.2 -- 0.2 -- (50) 100 " -- -- -- F -- 400 0.01 1 -- 0.1 (100) 95 0.1 10 1 2.5 2 5,600 3 30 9 (20) 20 82 0.6 10 0.7 E (150) 370 E 0.2 E 0_.5 0.5 1,600 0.1 10 0.2 0.7 (360) TENTATIVE VALUES STEL ppm"' mg/mJ>l _ -- _ _ _ 2 1,250 -- 30 _ (15) 10 _ 0.6 _ -- -- (75) _ _ 20 0_.3 4 7,000 -- 45 _ (60) 40 B2 1.8 _ -- E (225) 150 560 ' _ 0.6 -- _ F 20 1_.5 --2 500 2.000 0.03 0.3 3 30 _ 0.6 0.3 2 (125) (450) Capital letters refer to Appendices. '1979 Addition "See Notice of Intended Changes. 19 511904 0142 Substanceppm-1 mg/m1*' AOOPTEO VALUES TWA ppm*1 mg/m*' TENTATIVE VALUES STEL Skin...................... 2-Hexanone, see Methyl A2 A2 -- -- butyl ketone -- Skin .. 25 100 40 165 * Hexone (Methyl isobutyl ketone) --Skin....... (100) sec-Hexyl acetate......... 50 ; Hexylene glycol........... 25 Hydrazine -- Skin........ 0.1, A2 Hydrogen .................. F Hydrogenated terphenyls 0.5 Hydrogen bromide........ 3 (410) 300 125 0.1, A_2 5 10 (125) _-- _F _ (510) __ _ _ ' Hydrogen chloride........ ' Hydrogen cyanide -- 5 7-- -- Skin...................... (10) Hydrogen fluoride (as F). 3 (11) (15) 2 (16) Hydrogen peroxide...... Hydrogen selenide (as Se)........................ 1 0.05 1.5 2 0.2 _ 3 _ Hydrogen sulfide.......... Hydroquinone............. Indene...................... 10 -- 10 15 15 2 45 15 27 4 70 Indium & Compounds (as In) ................... 1 Iodine..................... -- 0.1 0.1 _ 1_ 0.3 Iodoform................... 0.6 10 1 20 Iron oxide fume (Fe203, as Fe).................... Iron pentacarbonyl (as 83 5-- 10 Fe)..... :................. Iron satts, soluble (as Fe)....................... Isoamyl acetate........... Isoamyl alcohol........... 0.01 _ 100 100 0.08 -- 1_ 525 125 360 125 -- 2 655 450 Isobutyl acetate........... Isobutyl alcohol.......... 150 50 700 187 150 75 875 225 Isophorone................ 5 25 -- Isophorone diisocyanate -- Skin.. 0.01 0.09 _ _ Isopropyl acetate......... Isopropyl alcohol -- Skin 250 400 950 310 1,185 980 500 1,225 Isopropylamine............ 5 12 10 24 Isopropyl ether............ 250 1.050 310 1.320 ii letters refer to Appendices. > Notice of Intended Changes. 20 Substance Isopropyl glycidyl ether (IGE)..................... Kaolin....................... Ketene...................... Lead, inorg., fumes & dusts (as Pb)........... Lead arsenate (as Pb).... Lead chromate (as Cr)... Limestone.................. Lindane -- Skin........... Lithium hydride.......... L.P.G. (Liquified petroleum gas)........ Magnesite.................. Magnesium oxide fume (as Mg).................. Malathion -- Skin....... Maleic anhydride.......... 1 Manganese & Compounds (as Mn).. ' Manganese fume (as Mn)...................... Manganese cyclopentadienyl tricarbonyl (as Mn) -- Skin...................... Manganese Tetroxide.... Marble/calcium carbonate............... Mercury (Alkyl compounds) -- Skin, (as Hg).................. Mercury (All forms except alkyl), as Hg ... Mesityl oxide.............. Methane.................... Methanethiol, see Methyl mercaptan.............. Methomyl (Lannate) -- Skin...................... Methoxychlor.............. ADOPTED VALUES TWA ppm"1 mg/m1*1 TENTATIVE VALUES STEL ppm"' mg/m*' 50 240 75 _ E-- 0.5 0.9 1.5 0.15 -- 0.15 -- 0.05, A2 -- _ E0.5 _ 0.025 _ _ ___ 1.000 -- _ -- 0.25 1.800 1,250 E_ 10 10 -- 1_ 5 _1 360 20 3 0.45 0.45 20 1.5 2,250 20 _ _ 3 0.1 -- 1_ E 0.001 (25) F 0.5 -- 0.01 0.003 0.05 (100) _ F 1 2.5 10 -- 03 _ 20 0 03 0.1_5 _ -- Capital letters refer to Appendices. *1979 Addition. "See Notices of Intended Changes. 21 511904 0143 ADOPTED TENTATIVE VALUES_________ VALUES TWA STEL Substance____________ ppm"1 mQ/m3*1 ppm-' 2-Methoxyethanol -- Skin (Methyl cellosolve).............. Methyl acetate............. Methyl acetylene (propyne) ............... Methyl acetylene-propadiene mixture (MAPP)....... Methyl acrylate -- Skin.. Methylacrylonitrile -- Skin...................... Methylal (dimethoxymethane).. Methyl alcohol (methanol) -- Skin.... Methylamme............... Methyl amyl alcohol, see Methyl isobutyl carbinol -- Skin...... Methyl 2-cyanoacrylate .. " Methyl n-amyl ketone (2-Heptanone).......... " Methyl bromide -- Skin . " Methyl butyl ketone, see 2-Hexanone --Skin... Methyl cellosolve -- Skin see 2-Methoxyethanol. Methyl cellosolve acetate -- Skin, see Ethylene glycol monomethyl ether acetate............ " Methyl chloride........... Methyl chloroform (1,1, 1-Trichloroethane).... Methylcyclohexane...... Methylcyclohexanol...... o-Methycyclohexanone -- Skin.................. Methylcyclopentadienyl manganese tricarbonyl (as Mn) -- Skin....... 25 200 1,000 1,000 10 1 1,000 200 10 25 2 (100) (15) (25) 25 25 (100) 350 400 50 50 0.1 80 35 610 250 1,650 1,250 1,800 1,250 35 -- 32 3,100 1.250 260 250 12 100 40 84 (465) (150) (60) (100) (40) 80 35 120 (210) 1,900 1.600 235 230 35 (125) 450 500 75 75 0.2 0.3 120 760 2,040 2,250 -- 6 3,875 310 "* 160 16 (710) (165) 120 170 (260) 2,380 2,000 350 345 0.6 Capital letters refers to Appendices. **See Notice of Intended Changes. 22 ADOPTED VALUES TWA Substance ppm"' _Methyl demeton -- Skin 0.5 C Methylene bisphenyl isocyanate (MDI)...... 0.02 0.2 ** Methylene chloride (dichloromethane).... (200) (700) 4,4'-Methylene bis (2-chloraniline) -- Skin...................... 0.02, A2 _ C Methylene bis (4-cyclo- hexylisocyanate)...... 0.01 0.11 Methyl ethyl ketone (MEK). see 2-Butanone............. C Methyl ethyl ketone 200 590 peroxide................. Methyl formate........... 0.2 100 1.5 250 **Methyl iodide --Skin.... Methyl isoamyl ketone... (5) 100 (28) 475 Methyl isobutyl carbinol -- Skin............... Methyl isobutyl ketone. 25 100 see Hexone --Skin ... 100 410 Methyl isocyanate -- Skin................... 0.02 Methyl mercaptan........ 0.5 0.05 1 Methyl methaciylate..... Methyl parathion -- Skin Methyl propyl ketone, 100 _ 410 0.2 see 2-Pentanone...... "C Methyl silicate............. "C a-Methyl styrene.......... Molybdenum (as Mo) 200 (5) (100) 700 (30) (480) Soluble compounds ... Insoluble compounds. -- _ 5 10 Monocrotophos (Azodrin)........... Monomethyl aniline -- -- 0,25 Skin..................... C Monomethyl hydrazine 2 9 -- Skin.................. 0.2 0.35 Morpholine -- Skin...... 20 70 Naphthalene.............. 10 50 TENTATIVE VALUES STEL ppm"1 1.5 __ (250) (870) A2 _ _ 300 885 __ 150 375 (10) (56) 150 710 40 165 125 510 _ _ __ 125 510 0.6 2_50 875 __ __ 10 20 __ 4 18 __ 30 105 15 75 Capital letters refer to Appendices. "See Notice of Intended Changes 23 511904 0144 Substanceppm` mgim1*' ADOPTEO VALUES TWA ppm"' mg/m1*1 TENTATIVE VALUES STEL /3-Naphthylamine......... -- Neon........................ F Nickel carbonyl (asNI)... 0.05 Nickel metal............... -- Nickel, soluble compounds (as Ni).... Nickel sulfide roasting, fume & dust (as Ni)... Nicotine -- Skin.......... _ Nitric acid.................. 2 Nitric oxide................ 25 p-Nitroaniline -- Skin.... 1 Nitrobenzene -- Skin.... 1 p-Nitrochlorobenzene -- Skin...................... 4-Nitrodiphenyl............ -- Nitroethane................ 100 Nitrogen dioxide......... (5) Nitrogen trifluoride...... 10 Nitroglycerin -- Skin.... (0.2) Nitromethane.............. 100 1-Nitropropane............ (25) 2-Nitropropane............ (25) n-Nitrosodimethylamine (dimethylnitrosoamine) -- Skin.................. Nitrotoluene -- Skin..... 5 Nitrotrichloromethane, see Chloropicrin....... 0.1 Nonane..................... 200 Octachloronaphthalene -- Skin.................. Octane...................... 300 Oil mist, mineral......... -- Osmium tetroxide (as Os)....................... 0.0002 Oxalic acid................. -- Oxygen difluoride......... 0.05 Ozone....................... Paraffin wax fume....... 0_.1 Paraquat, respirable sizes..................... Alb -- 0.35 1 0.1 1. Ala 0.5 5 30 6 5 1 Alb 310 (9) 30 (2) 250 (90) (90) -- F -- -- _ 4 35 2 2 -- 150 -- 15 _ 150 (35) -- A2 30 10 0.7 0.3 1.050 250 0.1 1,450 5'1 3_75 0.002 1 0.000_6 0.1 0.15 0.2 2 0_.3 0.1 A_lb _ _ 0.3 1.5 10 45 12 10 2 Alb 465 -- 45 _ 375 (135) A2 60 2 1,300 0.3 1,800 10 0.006 2 0.3 0.6 6 Capital letters refer to Appendices Footnotes (a thru f| see Page 31 "See Notice of Intended Changes. 24 Substance Paratfiion -- Skin........ Particulate polycyclic aromatic hydrocarbons (PPAH), as benzene solubles... Pentaborane............... Pentachloronaphthalene . Pentachlorophenol -- Skin...................... Pentaerythritol............. Pentane.................... 2-Pentanone ............... Perchloroethylene -- Skin...................... Perchloromethyl mercaptan.............. Perchloiyl fluoride....... Phenol -- Skin............ Phenothiazine -- Skin.... * n-Phenyl-betanaphthylamine.......... p-Phenylene diamine -- Skin...................... Phenyl ether (vapor)..... " Phenyl ether-Oiphenyl mixture (vapor)....... Phenylethyiene, see Styrene, monomer.... Phenyl glycidyl ether (PSE).................... Phenyl mercaptan........ Phenylhydrazine -- Skin. C Phenylphosphine......... Phorate (Thimet*) -- Skin...................... Phosdrin (Mevinphos) -- Skin.................. Phosgene (carbonyl chloride)................ Phosphine................. Phosphoric acid........... Capital letters refer lo Appendices. Footnotes (a thru f) see Page 31. *1 a79 Addition. "See Notice of Intended Changes ADOPTED VALUES TWA ppm"' mg/m1*' __ 0.1 0.2, Ala 0.005 0.01 __ 0.5 0.5 --E 600 1,800 200 700 100 670 0.1 0.6 3 14 5 19 __ 5 A2 A2 0.1 17 (D (7) 100 420 10 60 05 2 5 20 0.05 0.25 0.05 0.01 0.1 0.1 0.4 0.3 0.4 --1 TENTATIVE VALUES STEL ppm*1 mQ/m>*' _ 0.3 0.015 -- 750 250 150 Ala 0.03 2 1.5 20 2.250 875 1.000 6 26 10 38 10 2 14 (2) (14) 125 525 15 90 __ 10 45 __ 0.2 0.03 0.3 11 --3 25 511904 0145 ADOPTED VALUES TWA Substanceppm"1 mg/m1*1 Phosphorus (yellow).... Phosphorus pentachloride........... Phosphorus pentasulflde Phosphorus trichloride... Phthalic anhydride....... m-Phthalodinitrile......... Picloram (Tordon)..... Picric acid -- Skin....... Pival (2-Pivalyl-l. 3- indandione)............. Plaster of Paris............ Platinum (Soluble salts) as Pt..................... Polychtorobiphenyls, see Chlorodiphenyls -- Skin....................... Polytetrafluoroethylene decomposition products................ C Potassium hydroxide.... Propane .................... " /3-Propiolactone........... Propargyl alcohol -- Skin...................... n-Propyl acetate.......... Propyl alcohol --Skin... n-Propyl nitrate........... Prowlene.................. Propylene dichloride (1, 2-0 ichloropro pane).... **C Propylene glycol dinitrate -- Skin.................. Propylene glycol monomethyl ether.... Propylene imine -- Skin. " Propylene oxide........... Propyne, see Methyl acetylene................ Pyrethrum................. Pyridine.................... Quinone.................... RDX -- Skin............... -- -- 0.5 1 _ -- _ _ -- -- F -- 1 200 200 25 F 75 (0.2) 100 2 (100) 1.000 -- 5 0.1 -- 0.1 (1) 1 3 6 5 10 0.1 0.1 E 0.002 81 2 -- (A2) 2 840 500 105 -- 350 (*) 360 5 (240) 1,650 5 15 0.4 1.5 Capital letters refer to Appendices. "See notice of intended changes TENTATIVE VALUES STEL ppm*' mg/m1*' -- 0.3 (3) --3 ---- 4 _ _24 -- 20 _ 0.3 _ 0.3 20 -- _ F -- 3 250 250 40 F 110 -- 150 _ (150) 1.250 -- 10 0.3 -- 61 _ _ (A2) 6 1.050 625 470 -- 510 -- 540 _ (360) 2.040 10 30 2 3 26 Substance Resorcinol................. Rhodium, Metal fume and dusts (as Rh)..... Soluble salts (as Rh).. Ronnel...................... Rosin core solder pyrolysis products (as formaldehyde).......... Rotenone (commercial).. Rouge ...................... Rubber solvent (Naphtha)............... Selenium compounds (as Se)....................... Selenium hexafluoride, (as Se) .................. Sevin (see Carbaryl).... Silane (see Silicon tetrahydride)............ Silicon...................... Silicon carbide............ Silicon tetrahydride (Silane).................. ' Silver, metal and soluble compounds, as Ag .... : Sodium azide.............. Sodium fluoroacetate (1080) --Skin........ : Sodium hydroxide....... Starch ...................... Stibine...................... Stoddard solvent.......... Strychnine................. Styrene, monomer (Phenylethylene)...... Subtilisins (Proteolytic enzymes as 100% pure crystalline enzyme)................. Sucrose .................... Sulfur dioxide............. Sulfur hexafluoride...... Sulfuric acid............... Capital letters refer to Appendices. "See Notice of Intended Changes. AOOPTEO VALUES TWA ppm*1 mg/m1*' 10 45 -- 0.1 -- 0.001 10 -- -- -- 400 -- 0.05 -- 0.5 -- -- 0.5 -- 0.1 -- -- -- 0.1 100 -- (100) 0.1 5 E 1,600 0.2 0.2 5 0.7 E E 0.7 (001) 0.3 0.05 2 E 0.5 575 0.15 (420) -- 0.00006"' --E (5) (13) 1.000 6,000 --1 TENTATIVE VALUES STEL ppm*' mg/m1*' 20 90 -- 0.3 -- 0.003 _ 0.3 _ 10 -- 20 ---- ---- __ -- 10 _1 1.5 20 -- 20 1 1.5 _ (0.03) ---- _ _ 0.15 -- _ 20 0.3 1.5 125 720 -- 0.45 (125) (525) -- _ -- 1,250 -- -- 20 -- 7.500 -- 27 511904 0146 ADOPTED VALUES TWA Substanceppm' mg/m3*" Sulfur monochloride..... Sulfur pentafluorlde..... Sulfur tetrafluoride....... Sulfuryl fluoride.......... Systox, see Demeton -- Skin.................. 2, 4. 5-T ................... Tantalum................... TEOP -- Skin.............. Teflon decomposition products................ Tellurium & compounds (as Te)................... Tellurium hexafluoride. as Te..................... TEPP --Skin.............. "C Terphenyls................. 1. 1, 1, 2-Tetrachloro-2, 2-difluoroethane...... 1.1,2, 2-Tetrachloro-1, 2-difluoroethane...... 1, 1.2, 2-Tetrachloroethane -- Skin.................. Tetrachloroethylene, see Perchloroethylene -- Skin...................... Tetrachloromethane, see Carbon tetrachloride -- Skin.................. Tetrachioronaphthalene.. Tetraethyl lead (as Pb) -- Skin.................. Tetrahydrofuran.......... Tetramethyl lead (as Pb) -- Skin.................. Tetramethyl succinonitrile -- Skin . Tetranitromethane....... Tetiyl (2, 4, 6-trinitrophenylmethylnitramine) -- Skin..................... i 0.025 0.1 5 0.01 -- _ -- -- -- 0.02 0.004 (D 500 500 5 100 10 -- -- 200 -- 0.5 1 6 0.25 0.4 20 0.1 10 5 0.2 B1 0.1 0.2 0.05 (9) 4,170 4,170 35 670 65 2 0.100'' 590 0.150" 3 8 1.5 Capital letters refer to Appendices. 'See Notice of Intended Changes. TENTATIVE VALUES STEL ppm*' mg/m3*' 3 0.075 0.3 10 18 0.75 1- 40 0.03 0.3 -- _ 20 10 -- 0.6 -- B1 ---- --_ 0.01 0.2 ---- 625 5,210 625 5,210 10 70 150 1.000 20 130 --4 -- 0.3 250 735 -- 0.5 29 3.0 28 Substance ADOPTED TENTATIVE VALUES_________ VALUES TWA STEL _________ ppm01 mg/m3*' ppm1" mg/nt3*' Thallium, soluble compounds (as Tl) -- Skin...................... 4,4 -Thiobis (6-tert. -- butyl-m-cresol)......... _ Thiogtycolic acid.......... 1 Thiram................... Tin, inorganic compounds, except SnH and Sn02 (as Sn) Tin, organic compounds (as Sn) -- Skin........ Tin oxide (as Sn).......... Titanium dioxide (as Ti).. -- _ _ _ Toluene (toluol) -- Skin . 100 ! Toluene-2, 4-diisocyanate (TDI)... (0.02) o-Toluidine................. 5 Toxaphene, see Chlorinated camphene -- Skin.................. -- ' Tributyl phosphate....... -- 1, 2, 4-Trichlorobenzene 5 1,1,1-Trichloroethane, see Methyl chloroform 350 1,1, 2-Trichloroethane -- Skin.................. 10 Trichloroethylene........ (100) Trichloromethane, see Chloroform............. 10, A2 Trichloronaphthalene.... -- 1, 2, 3-Trichloropropane 50 1, 1, 2-Trichloro 1,2, 2-trifluoroethane...... 1,000 Triethylamme.............. 25 Tricyclohexyltin hydroxide (Plictran). -- Trifluoromonobromo- methane................. 1,000 Trimethyl benzene.... 25 Trimethyl phosphite..... 0.5 0.1 -- 10 5 ___ _ 5-- 2 0.1 E E 375 (0.14) 22 -- ___ _ 150 _ 10 0.5 _ (5) _ 40 -- 1.900 450 45 (535) 50, A2 5 300 20 (150) _ _ 75 7.600 1.250 100 40 5-- 6,100 1,200 125 35 2.6 -- 20 10 4 0.2 20 20 560 _ 44 2.0 (5) 2.380 90 (800) _ 10 450 9.500 160 10 7,300 170 Capital letters refer to Appendices '1979 Addition. "See Notice ot Intended Changes. 29 511904 0147 Substance ADOPTED VALUES TWA ppm"1 mg/m1*' TENTATIVE VALUES STEL ppm" mg/m1" 2, 4. 6-Trimtrophenol, see Picric ack) -- Skin 2, 4,6-Trinitrophenyl- methylnitramine, see Tetryl -- Skin.......... C 2, 4, 6-Trinitrotoluene (TNT).................... Triorthocresyl phosphate Triphenyl phosphate..... Tungsten & compounds, as W Soluble............... Insoluble............. Turpentine................. Uranium (natural) soluble & insoluble compounds, as U..... ' Vanadium (V2 Os), as V Oust..................... C Fume.................... Valeraldehyde............. Vinyl acetate............... ** Vinyl benzene, see Styrene.................. " Vinyl bromide............. ** Vinyl chloride.............. Vinyl cyanide, see Acrylonitrile -- Skin... Vinyl cyclohexene dioxide.................. Vinylidene chloride...... " Vinyl toluene............... VM&P Naphtha.......... Warfarin.................... Welding fumes (NOC)t.. ' Wood dust (nonallergenic)......... Xylene (0-. m-, p-isomers) -- Skin .... C m-Xylene a, a '-diamine. Xylidene -- Skin.......... _ -- -- -- 100 _ -- 50 10 (100) (250) (Ale) (20) 10 10 (100) 300 -- -- _ 100 -- 5 0.1 1.5 0.5 0.1 3 1 5 560 0.2 (0.5) (0.05) 175 30 (420) (1.100) -- (45) 60 40 (480) 1,350 0.1 5, B3 (5) 435 0.1 25 _ -- -- -- 150 _ -- -- 20 (125) -- (Ale) (30) _ 20 (150) 400 -- -- _ 150 -- 10 0.3 3.0 0.3. 6 3 10 840 0.6 (1.5) -- -- 60 (525) -- -- (65) _ 80 (720) 1,800 0.3 B3 (10) 655 -- 50 Capital letters refer lo Appendices. '1978 Addition. "See Nonce ol Intended Changes. 30 ADOPTED TENTATIVE VALUES_________ VALUES TWA STEL Substanceppm*1 mg/rn1*' ppm-' mg/m^' Yttrium..................... Zinc chloride fume....... Zinc chromate (as Cr).... Zinc oxide fume........... Zinc stearate............... Zirconium compounds (as Zr)................... --i --1 -- 0.05, A2 --5 --e _ _ -- _ -- 3 2 -- 10 20 -- 5--10 a) Parts of vapor or gas per million parts of contami nated air by volume at 25C and 760 mm. Hg. pres sure. b) Approximate milligrams of substance per cubic meter of air. d) < 7 Jim in diameter. e) As sampled by method that does not collect vapor. f) For control of general room air, biologic monitoring is essential for personnel control. Radioactivity: The Committee accepts the philosophy and recommendations of the National Council on Radia tion Protection and Measurements (NCRP) for the ioniz ing radiation TLV. The NCRP is charted by Congress to, in part, collect, analyze, develop and disseminate infor mation and recommendations about protection against radiation and about radiation measurements, quantities and units, including development of basic concepts in these areas. NCRP Report No. 39 (reference 1) provides basic philosophy and concepts leading to protection cri teria established in the same report. Other NCRP reports address specific areas of radiation protection and, col lectively, provide an excellent basis for establishing a sound program for radiation control. The Committee recommends the listed references as substantative docu mentation of a sound basis for ionizing radiation protec tion. The Committee also strongly recommends that all exposures to ionizing radiations be kept low as reason ably achievable within the stated guidance. References: 1. "Basic Radiation Protection Criteria," NCRP Report No. 39, issued January 15, 1971. 31 511904 0148 2. Maximum Permissible Body Burdens and Maximum Permissible Concentrations ol Radionuclides in Air and in Water for Occupational Exposure," US Department of Commerce, National Bureau of Standards Handbook 69, issued June 5. 1959, with Addendum 1 issued August 1963. Available as NCRP Report No. 22. The above documents, as well as information on nu merous other NCRP Reports addressing specific sub jects in ionizing radiation protection are available from:-5 NCRP Publications, PO Box 30175, Washington, DC ' 20014. Substance SIUCA, S1O2 Crystalline Quartz Cristobalite . T ridymite Silica, fused Tripoli ' 'Amorphous.. MINERAL OUSTS TLV in mppcf1": 3001" % quartz +10 TLV for respirable dust mg/m3: 10 mg/m3l> in % Respirable quartz +2 TLV for "total dust," respirable and nonrespirable: 30 mg/m3 % quartz +3 Use one-half the value calculated from the count or mass formulae for quartz, Use one-half the value calculated from formulae for quartz. Use quartz formulae. Use respirable"1 mass quartz for mula ........................... (20 mppcf1") SILICATES (< f% quartz)* * 'Asbestos, all forms Mica Mineral wool fiber (5 fibers/cc > 5^m in length'1; Ala) 20 mppcf 10 mg/m3 **See Nonce ol intended Changes. 32 Perlite Portland Cement Soapstone Talc (nonasbestiform) "Talc (fibrous), use Asbestos limit. "Tremolite, see Asbestos. 30 mppcf 30 mppcf 20 mppcf 20 mppcf COAL DUST 2 mg/m3 (respirable dust fraction < 5% quartz). If >5% quartz, use respirable mass formula. NUISANCE PARTICULATES (see Appendix E) 30 mppcf or 10 mg/m3" of total dust < 1 % quartz, or, 5 mg/m3 respirable dust. Conversion factors: mppcf x 35.3 = Million particles per cubic meter = particles per cc g) Millions of particles per cubic foot of air, based on impinger samples counted by light-field technics. h) The percentage of quartz in the formula is the amount determined from airborne samples, except in those instances in which other methods have been shown to be applicable. i) Both concentration and percent quartz for the appli cation of this limit are to be determined from the fraction passing a size-selector with the following characteristics: Aerodynamic Diameter (/xm) (unit density sphere) =e 2 2.5 3.5 5.0 10 % passing selector 90 75 50 25 0 j) containing <1% quartz; if quartz content > 1%, use formulae for quartz. k) Lint-free dust as measured by the vertical-elutriator, cotton-dust sampler described in the Transactions of "See Notice of Intended Changes. 33 511904 0149 the National Conference on Cotton Dust, J. R. Lynch, pg. 33. May 2,1970. l) As determined by the membrane filter method at 40Q-450X magnification (4 mm objective) phase con trast illumination. m) Based on "high volume" sampling. n) "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 Deposi tion and Retention of Inhaled Aerosols, p. 149. Academic Press, New York, New York, 1964. (2) Interim Guide for Respirable Mass Sampling, AIHA Aerosol Technology Committee, AHIA J. 31:2,1970, p. 133. NOTICE OF INTENDED CHANGES (for 1979) These substances, with their corresponding values, comprise those for which either a limit has been pro posed for the first time, or for which a change in the "Adopted" listing has been proposed. In both cases, the proposed limits should be considered trial limits that will remain in the listing for a period of at least two years. If, after two years no evidence comes to light that ques tions the appropriateness of the values herein, the val ues will be reconsidered for the "Adopted" list. Docu mentation is available for each of these substances. 34 Substance t Acetone.................... Acetylsalicylic acid (Aspirin)................. t Acrylic Acid................ Acrylonitrile................ Aniline and homologues -- Skin.................. Antimony, soluble salts (as Sb).................. Antimony trioxide production.............. Arsenic (soluble), as As . Arsenic trioxide production.............. Baytex ....................... t Butane....................... 12-Butoxyenthanol (Butyl Cellosolve)-Skin....... t sec-Butyl alcohol.......... + n-Butyl glyctdyl ether (BGE).................... o-sec Butylphenol -- Skin....................... Cadmium oxide production.............. Carbon disulfide........... t Carbon tetrachloride -- Skin....................... t Carbonyl fluoride.......... Chloroacetyl chloride.... Chloromethyl methyl ether..................... t t-Chloro-1-nitropropane. t Chloropentafluoroethane. 0-Chloroprene -- Skin... + Chromium metal.......... + Chromium (II) compounds (as Cr).... t Chromium (III) compounds (as Cr).... + Chromium (VI) compounds (as Cr) Water soluble Cr VI compounds............. TWA pptr' mg/m1*' 750 1780 5 10 30 Alb Alb 2 10 2 --, A2 -- 0.2 --. A2 -- 0.1 800 1900 25 120 100 305 25 135 5 --. A2 10 30 5. A2 30. A2 25 0.05 0.2 Alb Alb 2 10 1000 6320 10 45 _ 0.5 0.5 0.5 0.05 STEL ppmal mg/mJ#l 1000 2375 __ __ 5 20 --_ _ 0.3 _ 75 360 150 455 __ 20 125 5 15 __ __ __ __ __ Capital tetters refer to Appendices. *1979 Revision or Addition. 35 511904 0150 Substance Certain water insoluble Cr VI compounds..... + Chrysene................... Cobalt metal, dust & fume (as Co)........... C Cyanogen chloride....... t Cyclohexanone............ + Cyclopentane.............. Dalapon.................... 1, 2-Dibromoethane -- Skin...................... 1, 2-Dichloroethane..... Dichloromonofluoro- methane................. 11. 1-Dichloro-1- nitroethane.............. Dichloropropene.......... Diethanolamine............ t Oiethylamine............... t Diethyl ketone............. + Digtycidyl ether (DGE).... t Oioxane, tech, grade -- Skin....................... t Dipropyl ketone........... Divinyl benzene........... Epictilorhydrin --Skin... + 2-Ethoxyethanol -- Skin. 12-Ethoxyethyl acetate (Cellosolve acetate) -- Skin...................... t Ethyl acrylate -- Skin .... Ethylene dibromide, see 1. 2-Dibromoethane... Ethylene dichloride, see 1. 2-Oichloroethane ... tC Ethylene glycol, vapor.... t Ethylene glycol dinitrate.. t Ethylene oxide............. t Furfural -- Skin.......... + Glycidol (2, 3-Epoxy1-propanol)............. Hexachlorobutadiene.... + Hexane (n-hexane)....... (other Isomers)....... t Hexone (Methyl isobutyl ketone) -- Skin....... Capita' letters refer to Appendices 1979 Add-on TWA ppm"" mg/m1"' -- 0.05. Ala A2 A2 -- 0.05 0.3 0.6 25 100 600 1.720 1-- Alb Alb 10 40 10 40 2 10 15 3 15 10 30 200 705 0.1 0.5 25 90 50 235 10 50 2 10 50 185 50 270 5 20 Alb Alb 10 40 50 125 0.02 0.2 10 20 28 25 75 A2 A2 25 90 500 1.800 50 205 36 STEL ppm"1 mg/m'41 ---- ---- -- 0.1 _-- 100 400 900 2,580 ---- _ 15 60 ---- 10 60 10 50 _-- 25 75 ---- ---- 100 360 ---- ---- 5 20 100 370 100 540 25 100 ---- 15 60 ---- 0.04 0.4 ---- ---- 100 300 ---- 100 350 ---- 75 300 Substance TWA ppnt"1 mg/m*4' C Hydrogen cyanide -- Skin....................... 10 2-Hydroxypropyl acrylate -- Skin.................. 0.5 * Isopropoxyethanol........ 25 n-lsopropylaniline -- Skin....................... 2 t Mesityl oxide.............. 15 + Methacrylic acid........... 20 t Methyl n-amyl ketone (2-Heptanone).......... 50 + Methyl bromide -- Skin . 5 t Methyl n-butyl ketone.... 5 + Methyl chloride............ 50 Methylene chloride (dichloromethane).... 100 4, 4-Methylene dianiline. 0.1 + Methyl iodide -- Skin.... 2. A2 t Methyl isopropyl ketone . 200 + Methyl silicate............. 1 + a-Methyl styrene.......... 50 + Nitrogen dioxide......... 3 + Nitroglycerin............... 0.02 + 1-Nitropropane............ 15 C 2-Nitropropane............ 25. A2 t Phenyl ether -- Diphenyl mixture (vapor)....... 0.5 Phosphorous pentachloride........... 0.1 t Platinum metal............ -- t /3-Propiolactone........... 0.5, A2 Propionic acid............. 10 + Propylene glycol dinitrate 0.02 t Propylene oxide........... 20 Silver, metal............... -- t Silver, soluble compounds (as Ag)... -- Sodium bisulfite........... -- Sodium metabisulfite.... -- + Styrene, monomer (phenylethylene)...... 50 Sulfur dioxide............. 2 C Terphenyls................. 0.5 Tetrasodium pyrophosphate......... -- 10 3 105 10 60 70 235 20 20 105 360 0.8 10. A2 705 6 240 6 0.2 55 90. A2 4 1 1 1.5. A2 30 0.2 50 0.1 0.01 5 5 215 5 5 5 STEL ppm"' mg/m14' --_ ---- 75 320 5 20 ' 25 100 --_ 100 465 15 60 ---- 100 205 500 1,700 0.5 4 5 30 ---- 5 30 100 485 5 10 0.04 0.4 25 90 ---- 28 ---- __ 13 15 45 0.04 0.4 ---- --_ ---- --_ --_ 100 425 5 15 -- ___ ---- Capital letters refer to Appendices. +1979 Addition. 37 511904 0151 Substance t Toluene-2, 4-diisocyanate (TDI)... + Tributyl phospate........ Trichloroacetic acid...... t Trichloroethylene........ t Trimellitic anhydride..... t Vanadium (V2 Os), as V, dust & fume............ Vinyl bromide............. Vinyl chloride.............. + Vinyl toluene............... + Wood dust, hard wood (as in furniture making)................. TWA ppnr*1 tng/m^' 0.005 0.2 -- 50 0.005 0.04 2.5 1 270 0.04 -- 5. A2 5. Ala 50 0.05 20, A2 10. Ala 240 --1 STEl ppm*1 mg/m1*' 0.02 0.4 -- 150 -- -- -- -- 100 0.15 5 -- 805 -- -- -- -- 485 ---- NOTICE OF INTENOEO CHANGES MINERAL OUSTS Substance Asbestos Amosite............. Chrysotile........... Crocidolite.......... T remolite........... Other forms....... Diatomaceous earth, natural .............. Silica, amorphous... Talc (fibrous) TLV 0.5 fiber/cc, Ala 2 fibers/cc, Ala 0.2 fiber/cc, Ala 0.5 fiber/cc, Ala 2 fibers/cc, Ala 1.5 mg/m3, Respirable dust 6 mg/m3, Total dust (all sampled sizes) 3 mg/m3, Respirable dust (< 5 /tm) 0.5 fiber/cc APPENOIX A CARCINOGENS The Committee lists below those substances in in dustrial use that have proven carcinogenic in man, or have induced cancer in animals under appropriate exper imental conditions. Present listing of those substances carcinogenic for man takes two forms: Those for which +1979 Addition 38 a TLV has been assigned (la) and those for which envi ronmental conditions have not been sufficiently defined to assign a TLV (1b). Ala. Human Carcinogens. Substances, or substances associated with industrial processes, recognized to have carcinogenic or cocarcinogenic potential, with an assigned TLV: "Arsenic trioxide production "Asbestos, all forms' bis (Chloromethyl) ether Chromite ore processing (chromate) Nickel sulfide roasting, fume & dust Particulate Polycyclic Aromatic Hydrocarbons (PPAH) Vinyl chloride TLV (AS2O3, 0.05 mg/m3 as As) (SO2, C 5.0 ppm) (SbaOa, 0.5 mg/m3 (as Sb)) (5 fibers/cc, >5 in length) 0.001 ppm 0.05 mg/m3 (as Cr) 1.0 mg/m3 (as Ni) 0.2 mg/m3, as benzene solubles 5 ppm Alb. Human Carcinogens. Substances, or substances associated with industrial processes, recognized to have carcinogenic potential without an assigned TLV: Acrylonitrile 4-Aminodiphenyl (p-Xenylamine) Benzidine production Chloromethyl methyt ether 1. 2-Dibromoethane (Ethylene dibromide) /3-Naphthylamine 4-Nitrodiphenyl Cigarette smoking tan enhance the incidence ot respiratory cancers from this or others ot these sudstances or processes. "See Notice ot Intended Changes 39 511904 0152 For the substances in 1b, no exposure or contact by any route -- respiratory, skin or oral, as de tected by the most sensitive methods -- shall be permitted. The worker should be properly equipped to insure virtually no contact with the carcinogen. A2. Industrial Substances Suspect of Carcinogenic Po tential lor MAN. Chemical substances or sub stances associated with industrial processes, which are suspect of inducing cancer, based on either (1) limited epidemiologic evidence, exclusive of clinical reports of single cases, or (2) demon stration of carcinogenesis in one or more animal species by appropriate methods. 3-Amino 1,2, 4-triazole Antimony trioxide production* Benzene Benz(a)pyrene Beryllium 'Cadmium oxide production Chloroform Chromates of lead and zinc (as Cr) 3, 3 '-Dichlorobenzidine Dimethylcarbamyl chloride 1.1-Dimethyl hydrazine Dimethyl sulfate -- Skin Epichl.orhy drin Hexachlorobutadiene Hexamethyl phosphoramide -- Skin Hydrazine Lead chromate 4, 4 -Methylene bis (2-chloroaniline) -- Skin Monomethyl hydrazine ) 2-Nitropropane n-Nitrosodimethylamine i-Phenyl-beta-naphthylamine Propane sultone beta-Propiolactone Vinyl cyclohexene dioxide Zinc chromate (as Cr) (0.5 mg/m3) 10 ppm -- 2.0 /ig/m3 (0.05 mg/m3) 10 ppm 0.05 mg/m3 -- -- 0.5 ppm 0.1 ppm 5 ppm -- _ 0.1 ppm 0.05 mg/m3 0.02 ppm 0.2 ppm 25 ppm -- -- -- -- 10 ppm 0.05 mg/m3 jarette smoking can enhance the incidence of respiratory cancers this or others of these substances or processes. 40 For the above, worker exposure by all routes should be carefully controlled to levels consistent with the animal and human experience data (see Documentation), including those substances with a listed TLV. THE COMMITTEE GUIOEUNES FOR CLASSIFICATION OF EXPERIMENTAL ANIMAL CARCINOGENS The following, guidelines are offered in the present state of knowledge as an aid in classifying sub stances in the occupational environment found to be carcinogenic in experimental animals. A need was felt by the Threshold Limits Committee for such a classification in order to take the first step in developing an appropriate TLV for occupational exposure. Determination of Approximate Threshold of Re sponse Requirement. In order to determine in which category to classify an experimental carcin ogen for the purpose of assigning an industrial air limit (TLV), an approximate threshold of neoplastic response must be determined. Because of practi cal experimental difficulties, a precisely defined threshold cannot be attained. For the purposes of standard-setting, this is of little moment, as an ap propriate risk, or safety, factor can be applied to the approximate threshold, the magnitude of which is dependent on the degree of potency of the car cinogenic response. To obtain the best 'practical' threshold of neoplas tic response, dosage decrements should be less than logarithmic. This becomes particularly impor tant at levels greater than 10 ppm (or correspond ing mg/m3). Accordingly, after a range-finding de termination has been made by logarithmic decreases, two additional dosage levels are re quired within the levels of "effect" and "no effect" to approximate the true threshold of neoplastic re sponse. The second step should attempt to establish a me tabolic relationship between animal and man for the particular substance found carcinogenic in an imals. If the metabolic pathways are found compa- 41 511904 0153 rable, the substance should be classed highly sus pect as a carcinogen for man. If no such relation is found, the substance should remain listed as an experimental animal carcinogen until evidence to the contrary is found. Proposed Classification of Experimental Animal Carcinogens. Substances occurring in the occupa tional environment found carcinogenic for animals may be grouped into three classes, those of high, intermediate and low potency. In evaluating the in cidence of animal cancers, significant incidence of cancer is defined as a neoplastic response which represents, in the judgment of the Committee, a significant excess of cancers above that occurring in negative controls. EXCEPTIONS: No substance is to be considered an occupational carcinogen of any practical signifi cance which reacts by the respiratory route at or above 1000 mg/m3 for the mouse, 2000 mg/m3 for the rat; by the dermal route, at or above 1500 mg/kg for the mouse. 3000 mg/kg for the rat; by the gastrointestinal route at or above 500 mg/kg/d for a lifetime, equivalent to about 100 g T.D. for the rat, lOg T.D. for the mouse. These dosage limitations exclude such substances as dioxane and trichlorethylene from consideration as carcinogens. Examples: Dioxane -- rats, hepatocellular and nasal tumors from 1015 mg/kg/d, oral Trichloroethylene -- female mice, tumors (30/98 @ 900 mg/kg/d), oral Industrial Substances of High Carcinogenic Po tency in Experimental Animals. 1. A substance to qualify as a carcinogen of high potency must fulfill one of the three following conditions in two animal species; la. Respiratory. Elicit cancer from (1) dosages below 1 mg/m3 (or equivalent ppm) via the respiratory tract in 6- 7-hour daily repeated inhalation exposures throughout lifetime; or (2) from a single intratracheally admin- 42 istered dose not exceeding 1 mg of parti culate, or liquid, per 100 ml or less of an imal minute respiratory volume; Examples: bis-Chloromethyl ether, malign ant tumors, rats, @ 0.47 mg/m3 (0.1 ppm) in 2 years; Hexamethyl phosphoramide, nasal squamous cell carcino ma, rats, @ 0.05 ppm, in 13 months OR lb. Dermal. Elicit cancer within 20 weeks by skin-painting, twice weekly at 2 mg/kg body weight or less per application for a total dose equal to or less than 1.5 mg, in a biologically inert vehicle; Examples: 7, 12-Dimethylbenz(a)anthra cene -- skin tumors @ 0.120.8 mg T.D. in four weeks Benzo(a)pyrene, mice 12 /ig. 3X/wk for 18 mos. T.D. 2.6 mg, 90.9% skin tumors OR lc. Gastrointestinal. Elicit cancer by daily in take via the gastrointestinal tract, within six months, with a six-month holding period, at a dosage below 1 mg/kg body weight per day; total dose, rat, 50 mg; mouse, s 3.5 mg; Examples: 7, 12-Oimethylbenz(a)anthra cene -- mammary tumors from 10 mg IX 3-Methylcholanthrene -- Tumors @ 3 sites from 8 mg in 89 weeks Benzo(a)pyrene. mice, 3.9% leukemias, from 30 mg T.D. 198 days 2. Elicit cancer by all three routes in at least two animal species at dose levels prescribed for high or intermediate potency. 43 511904 0154 Industrial Substances of Intermediate Carcinogenic Potency in Experimental Animals. To qualify as a carcinogen of intermediate potency, a substance should elicit cancer, in two animal spe cies at dosages intermediate between those de scribed in A3a and A3c by two routes of adminis tration. Example: Carbamic add ethyl ester Dermal, mammary tumors, mice, 100%, 63 weeks, 500-1400 mg T.D. Gastrointestinal, various type tumors, mice 42 weeks, 320 mg T.D. Gastrointestinal, various type tumors, rats, 60 weeks, 110-930 mg T.D. Industrial Substances of Low Carcinogenic Potency in Experimental Animals. To qualify as a carcinogen of low potency, a sub stance should elicit cancer in one animal species by any one of three routes of administration at the following prescribed dosages and conditions: la. Respiratory. Elicit cancer from (1) dosages greater than 10 mg/m3 (or equivalent ppm) via the respiratory tract in 6- 7-hour, daily re peated inhalation exposures, for 12 months' exposure and 12 months' observation period: or (2) from intratracheally administered dos ages totaling more than 10 mg of particulate or liquid per 100 ml or more of animal minute respiratory volume; Examples: Beryl (beryllium aluminum silicate) malig. lung tumors, rats, @ 15 mg/m3 @ 17 months Benzidine, var. tumors, rats, 10-20 mg/m3 @ > 13 mos. OR lb. Dermal. Elicit cancer by skin-painting of mice in twice weekly dosages of > 10 mg/kg body weight in a biologically inert vehicle for at least 75 weeks, i.e., ^ 1,5g T.D. Examples: Shale tar, mouse, 0.1 ml x 50 = 5g T.D. 59/60 skin tumors 44 Arsenic trioxide, man, dose un known, but estimated to be high 1c. Gastrointestinal. Elicit cancer from daily oral dosages of 50 mg/kg/day or greater during the lifetime ofthe animal. APPENDIX B SUBSTANCES OF VARIABLE COMPOSITION B1 Polytetrafluoroethylene* decomposition products. Thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products con taining carbon, fluorine and oxygen. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxi city of the products, but air concentrations should be minimal. 82 Gasoline. The composition of gasoline varies greatly and thus a single TLV for all types of these materials is no longer applicable. In general, the aromatic hy drocarbon content will determine what TLV applies. Consequently the content of benzene, other aromat ics and additives should be determined to arrive at the appropriate TLV (Elkins, et al. A.I.H.A.J. 24:99, 1963); Runion, ibid. 36. 338,1975). B3 Welding Fumes -- Total Particulate (NOC)" TLV, 5 mg/m3 Welding fumes cannot be classified simply. The com position and quantity of both are dependent on the alloy being welded and the process and electrodes used. Reli able analysis of fumes cannot be made without consider ing the nature of the welding process and system being examined; reactive metals and alloys such as aluminum and titanium are arc-welded in a protective, inert atmo sphere such as argon. These arcs create relatively little fume, but an intense radiation which can produce ozone. Similar processes are used to arc-weld steels, also creating a relatively low level of fumes. Ferrous alloys also are arc-welded in oxidizing environments which generate considerable fume, and can produce carbon 'Trade Names: Algoflon. Fluon, Halon, Teflon. Telran. '' Not otnerwise classified (NOC) 45 511904 0155 monoxide instead of ozone. Such fumes generally are composed of discreet particles of amorphous slags con taining iron, manganese, silicon and other metallic con stituents depending on the alloy system involved. Chro mium and nickel compounds are found in fumes when stainless steels are arc-welded. Some coated and fluxcored electrodes are formulated with fluorides and the fumes associated with them can contain significantly more fluorides than oxides. Because of the above fac tors, arc-welding fumes frequently must be tested for individual constituents which are likely to be present to determine whether specific TLV's are exceeded. Conclu sions based on total fume concentration are generally adequate if no toxic elements are present in welding rod, metal, or metal coating and conditions are not conducive to the formation of toxic gases. Most welding, even with primitive ventilation, does not produce exposures inside the welding helmet above 5 mg/m3. That which does, should be controlled. APPENDIX C MIXTURES C.1 THRESHOLD LIMIT VALUES FOR MIXTURES When two or more hazardous substances are pres ent, their combined effect, rather than that of either indi vidually, should be given primary consideration. In the absence of information to the contrary, the effects of the different hazards should be considered as additive. That is, if the sum of the following fractions, exceeds unity, then the threshold limit of the mixture should be considered as being exceeded. Ci indicates the observed atmospheric concentration, and Ti the cor responding threshold limit (See Example lA.a. and 1 A.c.). Exceptions to the above rule may be made when there is a 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 compo nents of the mixture. In such cases the threshold limit ordinarily is exceeded only when at least one member of 46 the series + or + -y? etc.^ itself has a value exceeding unity (See Example 1 A.c.). Synergistic action or potentiation may occur with some combinations of atmospheric contaminants. Such cases at present must be determined individually. Poten tiating or synergistic agents are not necessarily harmful 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 exhi bited at high concentrations, 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 sub stance. 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, lacquer ing, certain foundry operations, diesel exhausts, etc. C.1A Examples of THRESHOLD LIMIT VALUES FOR MIXTURES The following formulae apply only when the compo nents in a mixture have similar toxicologic effects; they should not be used for mixtures with widely differing reactivities, e.g. hydrogen cyanide & sulfur dioxide. In such case the formula for Independent Effects (lA.c.) should be used. lA.a. General case, where air is analyzed for each com ponent: 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.) 47 511904 0156 Example No. 1A.a.: Air contains 400 ppm of acetone (TLV = 1000 ppm) 150 ppm of secbutyl acetate (TLV = 200 ppm) and 100 ppm of 2-butanone (TLV = 200 ppm) Atmospheric concentration of mix ture = 400 + 150 + 100 = 650 ppm of mixture 400 150 100 1000 + 200 + -stt- = 0.4 + 0.75 + 0.5 = 1.65 Threshold Limit Is exceeded. lA.b. 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 mate rial; e.g. on a time-weighted average exposure basis, all of the liquid (solvent) mixture eventually evaporates. 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, tor response to this specific quantitative and qualitative airvapor mixture, and also to fractional concen trations of this mixture: e.g., 112 the TLV; 1/10 the TLV; 2 x the TLV; 10 x the TLV; etc.) TLV of mixture = 1 f. U TLV,, TLV. TLV, f. ' ' TLV. Example No. 1: Liquid contains (by weight) 50% heptane: TLV = 400 ppm or 1600 mg/m3 1 mg/m3 0.25 ppm 350 ppm or 1900 mg/m3 1 mg/m3 = 0.28 ppm 48 20% perchloroethylene: TLV = 100 ppm or 670 mg/m3 1 mg/m3 = 0.15 ppm TLV of Mixture ^^ 1600 + 1900 + 670 1 0.00031 + 0.00016 + 0.00030 = oW= 1300 m9,m3 of this mixture 50% or (1300) (0.5) = 650 mg/m3 is heptane 30% or (1300) (0.3) = 390 mg/m3 is methyl chloro form 20% or (1300) (0.2) = 260 mg/m3 is perchloroethylene These values can be converted to ppm as follows: heptane: 650 mg/m3 x 0.25 = 162 ppm methyl chloroform: 390 mg/m3 x 0.18 = 70 ppm perchloroethylene: 260 mg/m3 x 0.15 = 39 ppm TLV of mixture = 162 + 70 + 39 = 271 ppm, or 1300 mg/m3 lA.c. Independent effects. Air contains 0.15 mg/m3 of lead (TLV, 0.15) and 0.7 mg/m3 of sulfuric acid (TLV, 1). *Ui=i' 0.15 JLL=o.7 1 Threshold limit is not exceeded. IB. TLV for Mixtures of Mineral Dusts. For mixtures of biologically active mineral dusts the general formula for mixtures may be used. For mixture containing 80% nonasbestiform talc and 20% quartz, the TLV for 100% of the mixture is given by: TLV=jrvir=9mppc< 20 + 2.7 TLV of nonasbestiform talc (pure) = 20 mppcf 49 511904 0157 TLV of quartz (pure) 300 100 + 10 = --300 = 2.7 mppcf 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 ex ample the limit for 20% quartz is 10 mppcf. For another mixture of 25% quartz, 25% amor phous silica and 50% talc: 25% quartz -- TLV (pure) = 2.7 mppcf 25% amorphous silica -- TLV (pure) = mppcf 50% talc TLV (pure) = 20 mppcf TLV = 0.25 2.7 = 8 mppcf 0.5 20 The limit for 25% quartz approximates 9 mppcf. APPENDIX D PERMISSIBLE EXCURSIONS FOR TIME- WEIGHTED AVERAGE (TWA) LIMITS The Excursion TLV Factor in the Table automatically defines 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 nitrobenzene, 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 sub stances with a "C" designation are not subject to the excursion factor and must be kept at or below the TLV ceiling. These limiting excursions are to be considered to provide a "rule-of-thumb" guidance for listed sub stances generally, and may not provide the most appro priate excursion for a particular substance e.g.. the per missible excursion for CO is 400 ppm for 15 minutes. For appropriate excursions for 142 substances con sult Pa. Rules & Regs., Chap. 4, Art. 432, and "Accept able Concentrations," ANSI. 50 Substance Nitrobenzene Carbon tetrachloride Trimethyl benzene Acetone Boron trifluoride Butylamine Max. Cone. Permitted Excursion for short TLV Factor time 13 10 2 25 1.5 1000 1.25 Cl -- C5 -- 2 20 35 1250 1 5 EXCURSION FACTORS For all substances not bearing C notation TLV>0-1 (ppm or mg/m3), TLV> 1-10 " TLV> 10-100 " TLV> 100-1000 " Excursion Factor " " =3 =2 =1.5 = 1.25 The number of times the excursion above the TLV is permitted is governed by conformity with the TimeWeighted Average TLV. INTERPRETATION OF MEASURED PEAK CONCENTRATIONS With increasing use of rapid, direct-reading analytical instruments for airborne contaminants in the work area, the question of interpretation of essentially "instanta neous" peaks arises. Although no general statement can be made covering all occupational substances, the fol lowing guidelines should prove helpful, assuming peak excursions conform to time-weighted average TLV as stated above. The toxicologic importance of momentary peak con centrations depends on whether the substance is fast or slow acting. II slow acting, as for quartz, lead, or car bon monoxide, momentary peaks are of no toxicologic concern provided, of course, they are not astronomic. On the other hand, fast-acting substances that rapidly produce disabling narcosis, e.g., faS. or intolerable irri tation orasphyxiation, NHj, SO2. CO2, or initiate sensitiza tion--the organic isocyanates, even "instantaneous" peaks appreciably above the permissible excursion, should not be permitted, unless information exists to the 51 511904 0158 contrary. Other more specific excursions will be devel oped in the future. APPENDIX E Some Nuisance Particulates" TLV, 30 mppcf or 10mg/m3 of total dust < 1 % quartz, or, 5 mg/m3 respirable dust Alundum Calcium carbonate Calcium silicate Cellulose (paper fiber) Portland Cement Corundum (AI2O3) Emery Glycerin Mist Graphite (synthetic) Gypsum Vegetable oil mists (except castor, cashew nut, or similar irritant oils) Kaolin Limestone Magnesite Marble Mineral Wool Fiber Pentaerythritol Plaster of Paris Silicon Silicon Carbide Starch Sucrose Tin Oxide Titanium Dioxide Zinc Stearate Zinc oxide dust n) When toxic impurities are not present, e.g. quartz < 1%. APPENDIX F Some Simple Asphyxiants'" Acetylene Argon Butane Ethane Ethylene Helium Hydrogen Methane Neon Propane Propylene p) As defined on pg. 6. APPENDIX G Conversion of mppcf to Mass Concentration Calculations for Conversion of Particle Count Concen tration (by Standard Light Field -- Midget Impinger Techniques), in mppcf, to Respirable Mass Concentra tion (by Respirable Sampler) in mg/m3.t f Relationship Between Gravimetric Respirable Oust Concentration and Midget Impinger Number Concentration." by Murray Jacobson and T F Tomb. AlHAj, 28 Nov -Dec 1967. 52 1. In 1967, Jacobsen and Tomb.t derived an empiri cal relationship of 5.6 mppcf to 1 milligram of respirable dust per cubic meter of air, based on 23 sets of samples, mostly coal dust. The follow ing calculation results in an equivalence of 6.37 mppcf to 1 mg/m3 of respirable dust. Thus, an approximate ratio of 6 mppcf to 1 mg/m3 of re spirable dust is suggested for conversion of TLVs from a count to a mass basis when the density and mass median diameter have not been deter mined. 2. Basic assumptions: a) Average density for silica containing dusts ** 2.5 gms/cm3 (2500 mg/cm3). Pulmonary sig nificant dust densities may vary from 1.2 gm/cm3 for coal dust to 3.1 gms/cm3 for Portland Cement. Silica densities vary from 2.2 (amorphous) to 2.3 (cristobalite and tridymite) to 2.5 (alpha-quartz.) gms per cm3. b) The mass median diameter (mmd) of particles collected in midget impinger samplers and counted by the standard light field technique, and collected in a respirable sampler is ap proximately 1.5 /tm or 1.5 x 10'* cm. This assumption is, of course, quite arbitrary since the mmd of all dust clouds is quite variable, depending on many independent parameters, such as source of dust, age of dust cloud, me teorological conditions, etc. 3. Calculation: a) vol. per particle: 4/3 rr r3; r = 0.75 x 10~4 cm = 4/3 *(0.75 x 10*4)3 = 1.77 x 10-,2cm3 b) wt. per particle = vol. x density = 1.77 x 10~12 cm3 x 2.5 x 103 mg/cm3 = 4.425 x 10-9 mg/particle c) 1 particle/ft.3 = 35.5 part./m3 (since 35.5 cu ft = 1 cu m.) 10s part./ft3 = mppcf = 35.5 x 10s part./m3 53 511904 0159 Wt. of 1 mppcf - 35.5 x 10s part./m3 x 4.425 x 10~ mg/part. 1 mppcf = 0.157 mg/m3 or 6.37 mppcf 1 mg/m3 mg/m3. or approximately 6 mpccf = 1 4. Equivalent TLVs in mppcf and mg/m3 (respirable mass) for Mineral Ousts. Substance Silica (SiOs) Amorphous Cristobalite Fused silica Quartz Tridymite Coal Oust Diatomaceous earth, natural Graphite (natural) Mica Mineral wool fiber Nuisance particulates Perlite Portland Cement Soapstone Talc * (nonasbestiform) Tripoli Threshold Limit Value Count Resp. Mass Total Mass* mppcf mg/m3 mg/m3 20 1.5 3 3 1.5 (12) -- 15 20 -- 30 30 30 20 20 (3) (3)** 0.05 0.1 0.1 0.05 2 1.5 (2.5) (3) (5) (5) (5) (5) (3) (3) 0.1 (6) 0.15 0.3 0.3 0.15 (4) _ (5) (6) 10 10 (10) (10) (6) (6) (0.3) TLVs Threshold Limit Values for Physical Agents Adopted by ACGIH for 1979 `Unless otherwise specified, respirable mass is presumed to equal ap proximately 50% of total mass. "All values in parentheses ( ) represent newly calculated values based on equivalence of 6 mppcf t mg/m1 respirable mass and respir able mass 50% total mass. 54 511904 0160 1979 TLV PHYSICAL AGENTS COMMITTEE Herbert H. Jones, Central Missouri State University, Chairman Peter A. Breysse, University of Washington Thomas Cummings, Dept, of Health -- Ontario, Canada Irving H. Davis, Dept, of Health -- Michigan Ronald D. Dobbin, NIOSH LCDR Joseph J. Drozd. USN Dr. Allan P. Heins, OSHA LCDR Richard Johnson, USN LTC. George S. Kush, USAF Edward J. Largent, Retired William E. Murray, NIOSH Dr. Wordie H. Parr, NIOSH David H. Sliney, USAEHA LTC Robert T. Wangemann, USA Thomas K. Wilkinson, USPHS-NIH CONSULTANTS Gerald V. Coles Any comments or questions regarding these limits should be addressed to: Executive Secretary American Conference of Governmental Industrial Hygien ists P.O. Box 1937 Cincinnati, OH 45201: (513) 941-0176 PREFACE PHYSICAL AGENTS These threshold limit values refer to levels of phys ical agents and represent conditions under which it is believed that nearly all workers may be repeatedly ex posed day after day without adverse effect. Because of wide variations in individual susceptibility, expo sure of an occasional individual at, or even below, the threshold limit may not prevent annoyance, aggrava tion of a pre-existing condition, or physiological dam age. These threshold limits are based on the best avail able information from industrial experience, from ex perimental human and animal studies, and when pos sible, from a combination of the three. These limits are intended for use in the practice of industrial hygiene and should be interpreted and ap plied only by a person trained in this discipline. They are not intended for use. or for modification for use. (1) in the evaluation or control of the levels of physi cal agents in the community, (2) as proof or disproof of an existing physical disability, or (3) for adoption by countries whose working conditions differ from those in the United States of America. These values are reviewed annually by the Com mittee on Threshold Limits for Physical Agents for re visions or additions, as further information becomes available. Notice of Intent --At the beginning of each year, proposed actions of the Committee for the forthcom ing year are issued in the form of a "Notice of Intent." This notice provides not only an opportunity for com ment but solicits suggestions of physical agents to be added to the list. The suggestions should be ac companied by substantiating evidence. As Legislative Code -- The Conference recognizes that the Threshold Limit Values may be adopted in legislative codes and regulations. If so used, the in tent of the concepts contained in the Preface should be maintained and provisions should be made to keep the list current. 57 511904 0161 Reprint Permission -- This publication may be printed provided that written permission is obtained from the Executive Secretary of the Conference and that this Preface be published in its entirety along with the Threshold Limit Values. THRESHOLD LIMIT VALUES HEAT STRESS These Threshold Limit Values refer to heat stress conditions under which it is believed that nearly all workers may be repeatedly exposed without adverse health effects. The TLVs shown in Table 1 are based on the assumption that nearly all acclimatized, fully clothed workers with adequate water and salt intake should be able to function effectively under the given working con ditions without exceeding a deep body temperature of 38C (WHO technical report series #412, 1969 Health Factors Involved In Working Under Conditions of Heat Stress; F. N. Oukes-Dobos and A. Henschel: "Develop ment of Permissible Heat Exposure Limits for Occupa tional Work." ASHRAE Journal, Vol. 15: No. 9, Sep tember 1973, pp. 57-62.) Since measurement of deep body temperature is im practical for monitoring the workers' heat load, the mea surement of environmental factors is required which most nearly correlate with deep body temperature and other physiological responses to heat. At the present time Wet Bulb-Globe Temperature Index (WBGT) is the simplest and most suitable technique to measure the en vironmental factors. WBGT values are calculated by the following equations: 1. Outdoors with solar load: WBGT = 0.7WB + 0.2GT + 0.1 DB 2. Indoors or Outdoors with no solar load: WBGT = 0.7W8 + 0.3GT where: WBGT = Wet Bulb-Globe Temperature Index WB = Natural Wet-Bulb Temperature DB = Dry-Bulb Temperature GT = Globe Thermometer Temperature 58 . The determination of WBGT requires the use of a black globe thermometer, a natural (static) wet-bulb thermom eter, and a dry-bulb thermometer. TABLE 1 Permissible Heat Exposure Threshold Limit Values (Values are given in C. WBGT) Work Load Work -- Rest Regimen Light Moderate Heavy Continuous work 30.0 26.7 25.0 75% Work -- 25% Rest, Each hour 30.6 28.0 25.9 50% Work -- 50% Rest, Each hour 31.4 29.4 27.9 25% Work -- 75% Rest, Each hour 32.2 31.1 30.0 Higher heat exposures than shown in Table 1 are per missible if the workers have been undergoing medical surveillance and it has been established that they are more tolerant to work in heat than the average worker. Workers should not be permitted to continue their work when their deep body temperature exceeds 38.0C. EVALUATION AND CONTROL I. Measurement of the Environment The instruments required are a dry-bulb, a natural wet-bulb, a globe thermometer, and a stand. The mea surement of the environmental factors shall be per formed as follows: A. The range of the dry and the natural wet bulb ther mometer shall be -5C to 50C with an accuracy of 0.5C. The dry bulb thermometer must be shielded from the sun and the other radiant surfaces of the envi ronment without restricting the airflow around the bulb. The wick of the natural wet-bulb thermometer shall be 59 511904 0162 kept wet with distilled water for at least 1/2 hour before the temperature reading is made. It is not enough to immerse the other end of the wick into a reservoir of distilled water and wait until the whole wick becomes wet by capillarity. The wick shall be wetted by direct application of water from a syringe 1/2 hour before each reading. The wick shall extend over the bulb of the ther mometer, covering the stem about one additional bulb length. The wick should always be clean and new wicks should be washed before using. B. A globe thermometer, consisting of a 15 cm. (6inch) diameter hollow copper sphere painted on the out side with a matte black finish or equivalent, shall be used. The bulb or sensor of a thermometer (range -5C to 100C with an accuracy of 0.5C) must be fixed in the center of the sphere. The globe thermometer shall be exposed at least 25 minutes before it is read. C. A stand shall be used to suspend the three thermom eters so that they do not restrict free air flow around the bulbs, and the wet-bulb and globe thermometer are not shaded. D. It is permissible to use any other type of temperature sensor that gives identical reading as that of a mercury thermometer under the same conditions. E. The thermometers must be so placed that the read ings are representative of the condition where the men work or rest, respectively. The methodology outlined above is more fully ex plained in the following publications: 1. `Prevention of Heat Casualties in Marine Corps Re cruits, 1955-1960, with Comparative Incidence Rates and Climatic Heat Stresses in other Training Catego ries," by Captain David Minard, MC, USN, Research Re port No. 4, Contract No. MR005.01-0001.01, Naval Medical Research Institute, Bethesda, Maryland, 21 Feb ruary 1961. 2. "Heat Casualties in the Navy and Marine Corps, 1959-1962, with Appendices on the Field Use of the Wet Bulb-Globe Temperature Index," by Captain David Minard, MC, USN, and R. L. O'Brien, HMC, USN. Re search Report No. 7, Contract No. MR 005.01-0001.01, Naval Medical Research Institute, Bethesda, Maryland, 12 March 1964. 60 3. Minard, D.: Prevention of Heat Casualties in Marine Corps Recruits. Military Medicine 126(4)- 261-272 1961. II. Work Load Categories Heat produced by the body and the environmental heat together determine the total heat load. Therefore, if work is to be performed under hot environmental condi tions, the workload category of each job shall be es tablished and the heat exposure limit pertinent to the work load evaluated against the applicable standard in order to protect the worker from exposure beyond the permissible limit. A. The work load category may be established by rank ing each job into light, medium, and heavy categories on the basis of type of operation. Where the work load is ranked into one of said three categories, i.e. (1) light work (up to 200 Kcal/hr or 800 Btu/hr): e.g., sitting or standing to control machines, performing light hand or arm work, (2) moderate work (200-350 Kcal/hr or 800-1400 Btu/hr): e.g., walking about with moderate lifting and pushing, (3) heavy work (350-500 Kcal/hr or 1400-2000 Btu/hr): e.g., pick and shovel work, the permissible heat exposure limit for that work load shall be determined from Table 1. B. The ranking of the job may be performed either by measuring the worker's metabolic rate while performing his job or by estimating his metabolic rate by the use of the scheme shown in Table 2. Tables available in the literature listed below and in other publications as well may also be utilized. When this method is used the per missible heat exposure limit can be determined by Figure 1. 1. Per-Olaf Astrand and Kaare Rodahl: "Textbook of Work Physiology" McGraw-Hill Book Company, New York, San Francisco, 1970. 2. "Ergonomics Guide to Assessment of Metabolic and Cardiac Costs of Physical Work." Amer. Ind. Hyg. Assoc. J. 32: 560, 1971. 3. Energy Requirements for Physical Work. Purdue 61 511904 Farm Cardiac Project. Agricultural Experiment Station. Research Progress Report No. 30,1961. 4. J. V. G. A. Durnin and R. Passmore: "Energy, Work and Leisure." Meinemann Educational Books, Ltd., Lon don, 1967. TABLE 2 Assessment of Work Load Average values of metabolic rate during different ac tivities. A. Body position and movement Sitting Standing Walking Walking up hill Kcal./min. 0.3 0.6 2.0-3.0 add 0.8 per meter (yard) rise B. Type of Work Average Range Kcal./min. Kcal./min. Hand work light heavy Work with one arm light heavy Work with both arms light heavy Work with body light moderate heavy very heavy 0.4 0.9 1.0 1.8 1.5 2.5 3.5 5.0 7.0 9.0 0.2-1.2 0.7-2.5 1.0-3.5 2.5-15.0 Light hand work: writing, hand knitting Heavy hand work: typewriting Heavy work with one arm: hammering in nails (shoe maker, upholsterer) Light work with two arms: filing metal, planing wood, raking of a garden 62 Moderate work with the body: cleaning a floor, beat ing a carpet Heavy work with the body: railroad track laying, dig ging, barking trees Sample Calculation: Using a heavy hand tool on an assembly line A. Walking along 2.0 Kcal./min. B. Intermediate value between heavy work with two arms and light work with the body 3.0 Kcal./min. C. Add for basal metabolism 5.0 Kcal./min. 1.0 Kcal./min. Total 6.0 Kcal./min. Adapted from Lehmann, G. E., A. Muller and H. Spitzer: Der Kalorienbedarf bei gewerblicher Arbeit. Arbeitsphysiol. 14:166,1950. III. Work-Rest Regimen The permissible exposure limits specified in Table 1 and Figure 1 are based on the assumption that the WBGT value of the resting place is the same or very close to that of the work place. Where the WBGT of the work area is different from that of the rest area a timeweighted average value should be used for both environ mental and metabolic heat. When time-weighted average values are used the appropriate curve on Figure 1 is the solid line labeled "continuous." The time-weighted average metabolic rate (M) shall be determined by the equation: Av. M = (Mi) x (ti) + (Ma) x (ta) *-..+ (M,,) x (t,,) (ti) + (ta) + ....+ (t.) Where Mi Ma, M,, are estimated or measured metabolic rates for the various activities of the worker during the total time period, ti, t2. t,, are the elapsed times in min utes spent at the corresponding metabolic rate as deter mined by a time study. The time-weighted average WBGT shall be deter mined by the equation: 63 511904 0104 Av. WBGT = (WBGTi) x (ti) + (WBGTz) x ta + .. . + (WBGT,) x (t,,) (tl) + (t2) + . . . + (t,) where WBGTi, WBGT2, WBGT, are calculated values of WBGT for the various work and rest areas occupied dur ing total time periods, ti, t2, t, are the elapsed times in minutes spent in the corresponding areas which are de termined by a time study. Where exposure to hot envi ronmental conditions is continuous for several hours or the entire work day. the time-weighted averages shall be calculated as hourly time-weighted average i.e., ti + t2 + . .. t, = 60 minutes. Where the exposure is intermit tent, the time-weighted averages shall be calculated as two-hour time-weighted averages, i.e., ti + t2 + . .. t, = 120 minutes. The permissible exposure limits for continuous work are applicable where there is a work-rest regimen of a 5-day work week and an 8-hour work day with a short morning and afternoon break (approximately 15 min utes) and a longer lunch break (approximately 30 min utes). Higher exposure limits are permitted if additional resting time is allowed. All breaks, including unsche duled pauses and administrative or operational waiting periods during work may be counted as rest time when additional rest allowance must be given because of high environmental temperatures. It is a common experience that when the work on a job is self-paced, the workers will spontaneously limit their hourly work load to 30-50% of their maximum physical performance capacity. They do this either by setting an appropriate work speed or by interspersing unscheduled breaks. Thus the daily average of the workers' metabolic rate seldom exceeds 330 kcal/hr. However, within an 8-hour work shift there may be periods where the workers' hourly average metabolic rate will be higher. IV. Water and Salt Supplementation During the hot season or when the worker is exposed to artificially generated heat, drinking water shall be made available to the workers in such a way that they are stimulated to frequently drink small amounts, i.e., one cup every 15-20 minutes (about 150 ml or 1/4 pint). 64 The water shall be kept reasonably cool (10-15C or 50.0-60.0F) and shall be placed close to the work place so that the worker can reach it without abandoning the work area. The workers should be encouraged to salt their food abundantly during the hot season and particularly during hot spells. If the workers are unacclimatized, salted drinking water shall be made available in a concentration of 0.1% (1g NaCI to 1.0 liter or 1 level tablespoon of salt to 15 quarts of water). The added salt shall.be complete ly dissolved before the water is distributed, and the water shall be kept reasonably cool. V. Other Considerations A. Clothing: The permissible heat exposure TLVs are valid for light summer clothing as customarily worn by workers when working under hot environmental condi tions. If special cothing is required for performing a par ticular job and this clothing is heavier or it impedes sweat evaporation or has higher insulation value, the worker's heat tolerance is reduced, and the permissible heat exposure limits indicated in Table 1 and Figure 1 are not applicable. For each job category where special clothing is required, the permissible heat exposure limit shall be established by an expert. B. Acclimatization and Fitness: The recommended heat stress TLVs are valid for acclimated workers who are physically fit. 65 511904 0165 400 <00 1200 1600 2000 BTU/hr Rot* of Work Figure 1 -- Permissible Heat Exposure Threshold Limit Value 66 IONIZING RADIATION The Committee accepts the philosophy and recommen dations of the National Council on Radiation Protection and Measurements (NCRP) for the ionizing radiation TLV. The NCRP is charted by Congress to, in part, col lect, analyze, develop and disseminate information and recommendations about protection against radiation and about radiation measurements, quantities and units, in cluding development of basic concepts in these areas. NCRP Report No. 39 (reference 1) provides basic philos ophy and concepts leading to protection criteria estab lished in the same report. Other NCRP reports address specific areas of radiation protection and, collectively, provide an excellent basis for establishing a sound pro gram for radiation control. The Committee recommends the listed references as substantative documentation of a sound basis for ionizing radiation protection. The com mittee also strongly recommends that all exposures to ionizing radiations be kept as low as reasonably achiev able within the stated guidance. References: 1. "Basic Radiation Protection Criteria," NCRP Report No. 39, issued January 15,1971. 2. Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure," US Department of Commerce, National Bureau of Standards Handbook 69, issued June 5, 1959, with Addendum 1 issued August 1963. Available as NCRP Report No. 22. The above doc uments, as well as information on numerous other NCRP Reports addressing specific subjects in ionizing radiation protection are available from: NCRP Publica tions, PO Box 30175, Washington, DC 20014. LASERS The threshold limit values are for exposure to laser radiation under conditions to which nearly all workers may be exposed without adverse effects. The values should be used as guides in the control of exposures and should not be regarded as fine lines between safe and dangerous levels. They are based on the best avail able information from experimental studies. 67 511904 0166 Limiting Apertures The TLVs expressed as radiant exposure or irradiance in this section may be averaged over an aperture of 1 mm except for TLVs for the eye in the spectral range of 400-1400 nm, which should be averaged over a 7 mm limiting aperture (pupil); and except for all TLVs for wa velengths between 0.1-1 mm where the limiting aper ture is 10 mm. No modification of the TLVs is permitted for pupil sizes less than 7 mm. The TLVs for "extended sources" apply to sources which subtend an angle greater than a (Table 5) which varies with exposure time. This angle is not the beam divergence of the source. Correction Factors A and B (CA and CB) The TLVs for ocular exposure in Tables 3 and 4 are to be used as given for all wavelength ranges. The TLVs for wavelengths between 700 nm and 1049 nm are to be increased by a uniformly extrapolated factor {CA) as shown in Figure 2. Between 1049 nm and 1400 nm, the TLV has been increased by a factor (C,,) of five. For certain exposure times at wavelengths between 550 nm and 700 nm, correction factor (Cs) must be applied. The TLVs for skin exposure are given in Table 6. The TLVs are to be increased by a factor (C*) as shown in Figure 2 for wavelengths between 700 nm and 1400 nm. To aid in the determination of TLVs for exposure dura tions requiring calculations of fractional powers Figures 3, 4, 5 and 6 may be used. Repetitively Pulsed Lasers Since there are few experimental data for multiple pulses, caution must be used in the evaluation of such exposures. The protection standards for irradiance or ra diant exposure in multiple pulse trains have the following limitations: (1) The exposure from any single pulse in the train is limited to the protection standard for a single compara ble pulse. (2) The average irradiance for a group of pulses is limited to the protection standard as given in Tables 3, 4, or 6 of a single pulse of the same duration as the entire pulse group. (3) When the Instantaneous Pulse Repetition Fre quency (PRF) of any pulses within a train exceeds one, 68 the protection standard applicable to each pulse is re duced as shown in Figure 6 for pulse durations less than 10~s second. For pulses of greater duration, the follow ing formula should be followed: Standard fs'ntgle pulse) = \in train / Standard (pulse nr) n where: n = number of pulses in train r = duration of a single pulse in the train Standard (nr) = protection standard of one pulse having a duration equal to nr sec onds. WavoUngth (nm) Figure 2 -- TLV correction factor for x = 700 - 1400 nm* `For X = 700 - 1049 nm, C.( = 10lo"- - TM'1 For x =. 1050 - 1400 nm, CH = 5 69 511904 0167 511904 0168 EXPOSURE DURATION U ) 72 73 5AA904 0'69 EXPOSURE DURATION (S ) 74 75 511904 0170 Figure Sb -- TLVlor intrabeam (direct) viewing ol CWlaser beam (400-1400 nm). TLV CORRECTION FACTOR 314 nm njLSC "tPtTrriON nvsuCNcr. ntr (hi) Figure 6 -- Multiplicative correction factor tor repetitively pulsed lasers having pulse durations less than 10~5 second. TLV for a single pulse of the pulse train is multiplied by the above correction factor. Correction factor for PRF greater than 1000 Hz is 0.06. 2Vl E-- ____________ooooo cn 2f LU O . *o" ac: "3 3u `5 to CO -->CO i>T*- S X ---- E sw " EE cc OQO COM CM CO EEEEEEEEEEEEE ceeecceeceece 222u'3<Ofs-CO>0*-CMCO oaoooooooo*------*-- CMCMCOCOCOCOCOCOCOCOCOCOCO 76 77 511904 0171 TABLE 3 (Cont.) i. C. and T, are the same as in footnote to Table 3. PE?E- E T 7E E. Ut EW >_ _E' re * E r ot u " ,, e T > E -Er = E; '*_ i E-; -E -- io X ( *-- uo < Ui/u)^inxoc>(Oif-"o>or x2 O x , O^ ^ 0 x1 Y T ooxoo , x^oi-^x2-x o - o o" o on 01 0 0i0f.xrt0_o0o0-^200~I mx-0,,I 0,I 0S0"I 0" 0o -cEEEEEEEi I o o 5 s OOrcs.OrOcsCc^iTnO)rc*O-OcNO.rOcO^o*O-^oT--O>'008^'^0o^r^^o^OO,,3.: OOOOOOOO------ oo EEEEEEEEcisE o= o=o=o=o=o=oo= L=n0m0 o= --a. OOOlOlOOOOOOO. 4-- 6 c o> 5 o O0 < cc O. c_.> 8r-~ ---8 7' 7E " Eo St ? .- - E f-Fo w ,, E CO SA-l-e v o a, M Iko s> o 5o CO CO -o CO o- -" -*--7. oO " . CTJ CO *-- cvj w evj oj f-*) o co E- T4 3 ^LU .2i2 . -CJD >w ' <o CxO or- _ X of WCD O a6 co co >" om ^ X UJ O O 1-- ^"Oco'" OIIO Oo Oo *o- ^O^ oi o** nO ol eeeeeeIII c = c= c c =ooo E 0oo0^0ro)o0o0T0rT0T0T0r cc OOOOOOOOOO EcEcEcEcEccEcEcEcEE^ Oco\joO^,oOn,mOu)OimniOorONoO.osOso--.-. 2o &I tr> ^ < cc 78 79 511904 0172 TABLE 5 Limiting Angle to Extended Source Which May Be Used for Applying Extended Source TLVs Exposure Duration(s) Angle a (mrad) * > t^ ^ ^ ^ COmcOCMv--CMCOtOO)^-- CMCMCMCM * <A ooooooooo1 80 CQ < Jr cn 81 X co o' oo o o oooo Ec Ec oo OO : CM V , o 2 03 Ot --5 i-<gc-- A co E E E* u CpD'c 5AA9QA - *) 0 (of X 400-700 nm. see Figure 2 for X 700 to 1400 nm. MICROWAVES These Threshold Limit Values refer to microwave en ergy in the frequency range of 300 MHz to 300 GHz and represent conditions under which it is believed that near ly all workers may be repeatedly exposed without ad verse effect. Under conditions of moderate to severe heat stress, the recommended values may need to be reduced.* Therefore, these values should be used as guides in the control of exposure to microwave energy and should not be regarded as a fine line between safe and dangerous levels. Recommended Values: The Threshold Limit Value for occupational exposure to microwave energy, where power density or field in tensity is known and exposure time is controlled, is as follows: 1. For exposure to continuous wave (CW) sources, the power density level shall not exceed 10 milliwatts per square centimeter (mW/cm2) for continuous expo sure, and the total exposure time shall be limited to an 8-hour workday. This power density is approxi mately equivalent to a free-space electric field strength of 200 volts-per-meter rms (V/m) and a free-space magnetic field strength of 0.5 ampere-permeter rms (A/m). 2. Exposures to CW power density levels greater than 10 mW/cm2 are permissible up to a maximum of 25 mW/cm2 based upon an average energy density of 1 milliwatt-hour per square centimeter (mWh/cm2) averaged over any 0.1 hour period. For example, at 25 mW/cm2, the permissible exposure duration is approximately 2.4 minutes in any 0.1 hour period. 3. For repetitively pulsed microwave sources, the average field strength or power density is calculated by multiplying the peak-pulse value by the duty cycle. The duty cycle is equal to the pulse duration in sec onds times the pulse repetition rate in Hertz. Expo sure during an 8-hour workday shall not exceed the `Mumlord. w W . Heal Stress Oue to fl F Radiation.' Proceedings of IEEE. Vol 57. No 2. Feb 1969. pp 171-178 62 following values which are averaged over any 0.1 hour period: Power Density Energy Density Mean Squared Electric Field Strength Mean Squared Magnetic Field Strength 10 mW/cm2 1 mWh/cm2 40,000 \P/m2 0.25 A2/m2 4. Exposure is not permissible in CW or repetitively pulsed fields with an average power density in excess of 25 mW/cm2 or approximate equivalent free-space field strengths of 300 V/m or 0.75 A/m. NOISE These threshold limit values refer to sound pressure levels and durations of exposure that represent condi tions under which it is believed that nearly all workers may be repeatedly exposed without adverse effect on their ability to hear and understand normal speech. The medical profession has defined hearing impairment as an average hearing threshold level in excess of 25 de cibels (ANSI-S3.6-1969) at 500, 1000, and 2000 Hz, and the limits which are given have been established to prevent a hearing loss in excess of this level. The values should be used as guides in the control of noise expo sure and, due to individual susceptibility, should not be regarded as fine lines between safe and dangerous levels. It should be recognized that the application of the TLV for noise will not protect all workers from the ad verse effects of noise exposure. A hearing conservation program with audiometric testing is necessary when workers are exposed to noise at or above the TLV levels. Continuous or Intermittent The sound level shall be determined by a sound level meter, conforming as a minimum to the requirements of the American National Standard Specification for Sound Level Meters, SI.4 (1971) Type S2A, and set to use the A-weighted network with slow meter response. Duration of exposure shall not exceed that shown in Table 7. These values apply to total duration of exposure per working day regardless of whether this is one continu ous exposure or a number of short-term exposures but does not apply to impact or impulsive type of noise. When the daily noise exposure is composed of two or more periods of noise exposure of different levels, 83 511904 0174 their combined effect should be considered, rather than the individual effect of each. If the sum of the following fractions: Ci C; C,, -- +17 + T,, exceeds unity, then, the mixed exposure should be con sidered to exceed the threshold limit value, Ci indicates the total duration of exposure at a specific noise level, and Ti indicates the total duration of exposure permitted at that level. All on-the-job noise exposures of 80 dBA or greater shall be used in the above calculations. Table 7 Threshold Limit Values Duration per day Hours 16 8 4 2 1 1/2 1/4 1/8 Sound Level dBA01 80 85 90 95 100 105 110 115* *No exposure to continuous or intermittent in excess of 115 dBA a) Sound level in decibels as measured on a sound level meter, conforming as a minimum to the require ments of the American National Standard Specifica- ' tion for Sound Level Meters, SI.4 (1971) Type S2A, and set to use the A-weighted network with slow meter response. IMPULSIVE OR IMPACT NOISE It is recommended that exposure to impulsive or im pact noise shall not exceed the limits listed in Table 8 or taken from Figure 7. No exposures in excess of 140 de cibels peak sound pressure level are permitted. Impul sive or impact noise is considered to be those variations in noise levels that involve maxima at intervals of greater 84 than one per second. Where the intervals are less than one second, it should be considered continuous. Sound Level dB" 140 130 120 Table 8 Threshold Limit Values Impulsive or Impact Noise Permitted Number of Impulses or Impacts per day 100 1000 10,000 "Oecibels peak sound pressure level. NUMtCI Of IMPVUCS Ot IMPACTS f OAT (M) Figure 7 -- Threshold Limit Values for Impulse/Impact Noise. 85 511904 0175 ULTRAVIOLET RADIATION* These threshold limit values refer to ultraviolet radia tion in the spectral region between 200 and 400 nm and represent conditions under which it is believed that near ly all workers may be repeatedly exposed without ad verse effect. These values for exposure of the eye or the skin apply to ultraviolet radiation from arcs, gas, and vapor discharges, fluorescent, and incandescent sources, and solar radiation, but do not apply to ultravi olet lasers.* These values do not apply to ultraviolet ra diation exposure of photosensitive individuals or of indi viduals concomitantly exposed to photosensitizing agents (Fitzpatrick, et al., eds., Sunlight and Man, Univ. Tokyo Press, Tokyo, Japan, 1974). These values should be used as guides in the control of exposure to continu ous sources where the exposure duration shall not be less than 0.1 sec. These values should be used as guides in the control of exposure to ultraviolet sources and should not be re garded as a fine line between safe and dangerous levels. Recommended Values: The threshold limit value for occupational exposure to ultraviolet radiation incident upon skin or eye where irradiance values are known and exposure time is con trolled are as follows: 1. For the near ultraviolet spectral region (320 to 400 nm) total irradiance incident upon the unprotected skin or eye should not exceed 1 mw/cm2 for periods greater than 103 seconds (approximately 16 minutes) and for exposure times less than 103 seconds should not exceed one J/cm2. 2. For the actinic ultraviolet spectral region (200 -- 315 nm), radiant exposure incident upon the unprotected skin or eye should not exceed the values given in Table 9 within an 8-hour period. 3. To determine the effective irradiance of a broadband source weighted against the peak of the spectral ef fectiveness curve (270 nm), the following weighting formula should be used: Eeff = 2 E* S,, AX "See Laser TLVs. 86 where: Eeff = effective irradiance relative to a monochromat ic source at 270 nm in W/cm2 (J/s/cm2) E* = spectral irradiance in W/cm2/nm S* = relative spectral effectiveness (unitless) AX = band width in nanometers 4. Permissible exposure time in seconds for exposure to actinic ultraviolet radiation incident upon the un protected skin or eye may be computed by dividing 0.003 J/cm2 by E^/ in W/cm2. The exposure time may also be determined using Table 10 which pro vides exposure times corresponding to effective irradiances in nW/cm2. TABLE 9 Relative Spectral Effectiveness by Wavelength Wavelength (nm) 200 210 220 230 240 250 254 260 270 280 290 300 305 310 315 TLV (mJ/cm2)** 100 40 25 16 10 7.0 6.0 4.6 3.0 3.4 4.7 10 50 200 1000 Relative Spectral Effectiveness Sa 0.03 0.075 0.12 0.19 0.30 0.43 0.5 0.65 1.0 0.88 0.64 0.30 0.06 0.015 0.003 "lm J/cm2 = to-2 J/cm2 87 511904 0176 TABLE 10 Permissible Ultraviolet Exposures Duration of Exposure Per Day Effective Irradiance, E//(/xW/cm^)," 8hrs.................................................. 0.1 4 hrs................................................. 0.2 2hrs.................................................. 0.4 1 hr................................................... 0.8 30 min............................................... 1.7 15 min............................................... 3.3 10 min............................................... 5 5 min................................................. 10 1 min................................................. 50 30 sec................................................ 100 10 sec................................................ 300 1 sec.................................................. 3,000 0.5 sec.............................................. 6,000 0.1 sec...............................................30,000 All the preceding TLV's for ultraviolet energy apply to sources which subtend an angle less than 80. Sources which subtend a greater angle need to be measured only over an angle of 80. = 10"* W/cm2 Figure 8 -- Threshold Limit Values for Ultraviolet Radiation Conditioned (tanned) individuals can tolerate skin ex posure in excess of the TLV without erythemal effects. However, such conditioning may not protect persons against skin cancer. NOTICE OF INTENDED CHANGES (for 1979) These physical agents, with their corresponding val ues, comprise 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. In both cases, the proposed limits should be considered trial limits that will remain in the listing for a period of at least one year. If after one year no evidence comes to light that questions the appropriateness of the values herein the values will be reconsidered for the "Adopted" list. 89 511904 0177 NOTICE OF INTENT TO ESTABLISH THRESHOLD LIMIT VALUES LIGHT ANO NEAR-INFRARED RADIATION These Threshold Limit Values refer to visible and near-infrared radiation in the wavelength range of 400 nm to 1400 nm and represent conditions under which it is believed that nearly all workers may be exposed with out adverse effect. These values should be used as guides in the control of exposure to light and should not be regarded as a fine line between safe and dangerous levels. Recommended Values: The Threshold Limit Value tor occupational exposure to broad-band light and near-infrared radiation for the eye apply to exposure in any eight-hour workday and require knowledge of the spectral radiance (LJ and total irradiance (E) of the source as measured at the posi tion^) of the eye of the worker. Such detailed spectral data of a white light source is generally only required if the luminance of the source exceeds 1 cd cm-2. At lu minances less than this value the TLV would not be ex ceeded. The TLV's are: 1. To protect against retinal thermal injury, the spectral radiance of the lamp weighted against the function R (Table 11) should not exceed: 1400 V, SLR4AAsi/at (1)* where L is in W cm-2 sr' and t is the viewing duration (or pulse duration if the lamp is pulsed) lim ited to 1 /is to 10 s, and a is the angular subtense of the source in radians. If the lamp is oblong, a refers to the longest dimension that can be viewed. For in stance, at a viewing distance r = 100 cm from a tubular lamp of length I = 50 cm, the viewing angle is: a = l/r = 50/100 = 0.5 rad (2) 2. To protect against retinal photochemical injury from chronic blue-light exposure the integrated spectral ra 90 diance of the lamp weighted against the blue-light hazard function B4 (Table 11) should not exceed: 1400 2 L t Bx AA ^ 100 Jem-2sr*'(trio's) (3a) 1400 ^2 L B* AA 10-2 Wcm-2 sr*' (t > 10*s) (3b) For a source radiance L which exceeds 2 mW cm-2 sr' in the blue spectral region, the permissible ex posure duration lMI in seconds is simply: tx= 100Jem*2sr'/L(blue) (4) The latter limits are greater than the maximum per missible exposure limits for 440 nm laser radiation (see Laser TLV) because a 2-3 mm pupil is assumed rather than a 7 mm pupil for the Laser TLV. 3. Infrared Radiation: To avoid possible delayed effects upon the lens of the eye (cataractogenesis), the infra red radiation (A > 770 nm) should be limited to 10 mWcm"2. For an infrared heat lamp or any near-in frared source where a strong visual stimulus is ab sent, the near infrared (770-1400 nm) radiance as viewed by the eye should be limited to: 1400 2o Lx AA = 0.6/a (5)* for extended duration viewing conditions. This limit is based upon a 7 mm pupil diameter. 'Formulae (1) and (2) are empirical and are not. strictly speaking, di mensionally correct. To make the formulae dimensionally correct, one would have to insert a dimensional correction factor k in the right hand numerator in each formula. For formula (1) this would be k, 1 W rad sMutcm* sr). and for formula {a) k, * 1 W rad/fcm* sr). 91 511904 0178 TABLE 11 SPECTRAL WEIGHTING FUNCTIONS FOR ASSESSING RETINAL HAZARDS FROM BROAD -- BAND OPTICAL SOURCES Wavelength (nm) 400 405 410 415 420 425 430 435 440 445 450 455 460 465 470 475 480 485 490 495 500-600 600-700 700-1049 1050-1400 Blue-Light Hazard Function B. 0.10 0.20 0.40 0.80 0.90 0.95 0.98 1.0 1.0 0.97 0.94 0.90 0.80 0.70 0.62 0.55 0.45 0.40 0.22 1Q(U0S.O1-A6>/SO] 0.001 0.001 0.001 Burn Hazard Function R 1.0 2.0 4.0 8.0 9.0 9.5 9.8 10 10 9.7 9.4 9.0 8.0 7.0 6.2 5.5 4.5 4.0 2.2 1.6 1.0 1.0 1Ql<700-*)/$0S| 0.2 AIRBORNE UPPER SONIC AND ULTRASONIC ACOUSTIC RAOIATION These threshold limit values refer to sound pressure levels that represent conditions under which it is be lieved that nearly all workers may be repeatedly exposed without adverse effect. The values listed in Table 15 should be used as guides in the control of noise expo sure and, due to individual susceptibility, should not be regarded as fine lines between safe and dangerous levels. The levels for the third octave bands centered below 20 kHz are below those which cause subjective effects. Those levels for 1/3 octaves above 20 kHz are for prevention of possible hearing losses from subhar monics of these frequencies. TABLE 12 Permissible Ultrasound Exposure Levels Mid-Frequency of Third-Octave Band kHz One-Third Octave -- Band Level in dB reference 0.0002 dynes/cm2 10 80 12.5 80 16 80 20 105 25 110 31.5 115 40 115 50 115 92 93 511904 0179 PHYSICAL AGENTS UNDER STUDY The Physical Agents Committee of ACGIH has exam ined the current literature and has not found sufficient information to propose a TLV. However, these agents will remain under study during the coming year to exam ine new evidence indicating the need and feasibility for establishing a proposed TLV. Comments and sugges tions, accompanied by substantive documentation are solicited and should be forwarded to the Executive Sec retary, ACGIH, Documentation summarizing the current status of the biological effects literature is available on those agents preceded by an asterisk. 1. Radiofrequency Radiation. Specifically, that portion of the spectrum from 10 MHz to 100 MHz. 2. Extremely Low Frequency (ELF) Radiation. Specifical ly, that portion of the spectrum from 0 to 300 Hz. 3. Magnetic Fields. Both pulsed and continuous. 4. Laser Radiation. Specifically ultraviolet radiation for pulsed exposures, and repetitively pulsed light and infrared-A laser ex posures. 5. Ultrasonic Energy. Specifically, acoustic energy at frequencies above 10 kHz. 6. Vibration. Segmental and whole-body. 7. Cold Stress. 8. Pressure Variations. The American Conference of Governmental Industrial Hy gienists was organized in 1938 by a group of govern mental industrial hygienists who desired a medium for the free exchange of ideas, experiences and the promo tion of standards and techniques in industrial health. The Conference is not an official Government Agency. It is an organization devoted to the development of ad ministrative and technical aspects of worker health pro tection. The association has contributed substantially to the development and improvement of official industrial health services to industry and labor. The committees on Industrial Ventilation and Threshold Limit Values are rec ognized throughout the world for their expertise and contributions to industrial hygiene. Membership is limited to professional personnel in gov ernmental agencies or educational institutions engaged in occupational safety and health programs. The more than 2300 members from across the United States and around the world give the organization an international scope. i 94 511904 0180