Document R0yq0GjkvRd3wEnzkpJa4nYE

i 1 1 \ ii i i I ARD 002702 Chapter II TOXICITY AND THRESHOLD LIMITS l. Protective Mechanisms II. Degrees of Toxicity III. Human Variabilities IV. Routes of Entry A. Inhalation 1. Work vs Breathing Rate 2. Altitude vs Breathing Rate 3. C02 vs Breathing Rate 4. Other Chemicals vs Breathing Rate 5. Fate of Inhaled Materials a. Gases and Vapors of High Solubility b. Gases and Vapors of Low Solubility c. Gases and Vapors of Intermediate Solubility d. Aerosols 6. Toxic Responses 7. Interpretation of Atmospheric Analyses a. Broad Line Between Safe and Harmful b. Short Duration Exposures c. Threshold Limit Values B. Ingestion C. Skin Absorption V. Dermatitis A. Causes of Dermatitis B. Symptoms of Dermatitis ARD 002703 Aluminum Company of America INDUSTRIAL HYGIENE HANDBOOK Chapter 11 Toxicity and Threshold Limits Bodily Protective Mechanisms In his daily life man is subjected to a host of environmental stresses which would ser iously threaten his existence were it not for the various protective mechanisms of his body. These protective mechanisms are quite effective; in fact man has much more natural protection against extraneous chemicals than have vegetation and materials of construction. In spite of this natural capacity for handling considerable stress, man's capacity to protect himself can be exceeded. When this happens the health of his body is impaired. Degrees of Toxicity Stresses may take the form of physical, chemical, biological or emotional insults. If the excessive insult is chemical, poisoning or intoxication results. The toxicity of a chemical, though, is a relative property. For example, sodium chloride is an essential requirement of the body. When deficient in this salt the body experiences a serious impairment of its functions. On the other hand, the ingestion of too much salt leads to intoxication. At certain levels, then, sodium chloride is toxic. It follows that the degree of toxicity of any material is judged by the dose required to exceed the capacity of the body defense mechanisms. Human Variabilities The biological variabilities characteristic of the human species have caused much con fusion in those charged with the responsibility for determining the maximum concentration levels of potentially toxic chemicals that man can safely tolerate. But men, like all other living things, generally respond in a similar pattern to any given toxic material. These usual reactions are known as normal responses. When the response is outside of that normally expected, the affected indivi dual is'said to be either sensitive or resistant to the material in question. In industry, the factor of sensitivity is most commonly associated with the susceptibility of an individual to dermatitis and, somewhat less frequently, to irritation of the eyes and upper respiratory tract. Inhalation There are many routes of entry of chemicals into the body. Those of importance in indus trial hygiene are inhalation, ingestion and skin absorption. Of these, inhalation is by far the most important. The primary function of the respiratory tract is to provide an exchange between the body organs and its gaseous environment. The structure of the respiratory organs is unique in that it provides a shield against environmental, biological and chemical stresses during this exchange. This is accomplished in part by the ciliary cells maintaining a fresh mucous lining in both the upper and lower respiratory tract. Inhaled foreign material is captured in the lining by impingement or dissolution. Displaced mucous containing the entrapped foreign material is swept into the throat through ciliary activity and then either expectorated or, as is more generally the case, swallowed. However, the capture of toxic material in the mucous lining can also have deleterious effects. Captured material may be absorbed directly or may cause irritation or may impair the ciliary activity, resulting in a predisposition to respiratory infection. 2-1 ARD 002704 Work vs. Breathing Rate Of all factors influencing the breathing rate of man, work is the most important. This is illustrated in Table 2.1. The table shows that as a man works harder, his breathing rate accelerates and his total air intake increases. It is easy to see that the greater the air intake, the greater will be the amounts of airborne contaminants taken into his system. In order to establish maximum safe limits of atmospheric concentrations (or threshold limits) for many of the contaminants to which a man is exposed, it is necessary to know his total requirement for air while on the job. During an eight-hour work day, the average employee breathes about-ten cubic meters of-air. This represents a work load comparable to walking at a rate of two to four miles per hour. Table 2.1 Oxygen Consumption and Volume of Breathing by Man Oxygen consumed at 0 C. and 760 mm pressure, liters per minute__________ Air breathed at 20 C., liters per minute Resting in bed 0.24 6 Sitting 0.30 7 Standing 0.36 8 Walking 2 m.p.h. 0.65 14 Walking 4 m.p.h. 1.20 26 Slow run 2.00 43 Maximum exertion 3.00-4.00 65-100 SOURCE: Henderson and Haggard Noxious Gases and the Principles of Respiration Influencing Their Action, Fbinhold Pub. Corp. New York, N.Y., 1943 Altitude vs. Breathing Rate At high altitudes, the body must compensate for the decreased oxygen content of air by more rapid breathing. At high altitudes a man will inhale more than the usual 10 mJ in 8 hours. Since the threshold limits are based on this volume of inspired air, it should be realized that a threshold limit in high altitude environments would necessarily be somewhat lower. This factor, however, is unimportant in the areas where Alcoa plants are located and may be ignored. CO2 vs. Breaching Race Since the carbon dioxide content of the blood is very influential in regulating the rate of breathing, it would appear then that the presence of carbon dioxide in air would also affect the breathing rate. However, stimulation of the breathing rate from a practical standpoint does not occur until the carbon dioxide content of the inhaled air exceeds about 2% (20,000 ppm). Such a high level is very unlikely under most conditions. 2-2 ARD 002705 Other Chemicals vs. Breathing Rate Some chemicals, notably carbon monoxide and certain nitroaromatic compounds, are able to combine with blood hemoglobin in such a way that the affected hemoglobin is unable to transport oxygen. The body attempts to compensate for this oxygen deficiency by an increase in the breathing rate. If atmospheric levels of these substances are held within the threshold limit (assuming the portal of entry to be inhalation), their effect on the rate of respiration is generally small. Gases and Vapors of High Solubility The fate of inhaled substances depends primarily on their physical characteristics, i.e., particle size, solubility and atmospheric concentration. Gases and vapors of high solubility such as hydrochloric, hydrofluoric and acetic acids, and the lower alcohols, aldehydes and ketones are largely removed by dissolving in the mucous of the upper respiratory tract. Some absorption may occur directly in the upper respiratory tract but, for the most part, the material is collected by the mucous and swallowed. Thus, to all intent and purpose, it has the same toxic action as if it were ingested. On the other hand, if the concentrations of non-irritating, soluble gases and vapors are sufficiently heavy, they may penetrate deeply. Heavy concentrations of irritants produce a throat spasm. Gases and Vapors of Low Solubility Gases and vapors of low solubility such as chlorinated and aliphatic hydrocarbons, the higher alcohols, hydrogen sulfide, oxides of nitrogen, ozone, mercury vapor, etc., readily reach the alveolar sacs of the lungs. They may be absorbed at this point and enter the blood stream or react with the tissue at the point of contact to produce an edema. The specific action of the inhaled material depends upon its toxic properties. Gases and Vapors of Intermediate Solubility Gases and vapors of intermediate solubility such as sulfur dioxide, chlorine and certain organic solvents, tend to be removed all along the respiratory tract. Thus, they may enter the body through the lungs and the digestive tract. Aerosols Aerosols (dusts, mists and fumes) above ten microns will be largely removed in the nasal passages and the back of the throat. A substantial part of the particulates between one and ten microns will also be removed in the upper respiratory tract but a significant portion will go beyond to be removed in the trachea and bronchial passages. Some, especially those in the low micron range, will gain access to the alveoli. In contrast, only a small portion of inhaled submicron particles will be removed in either the upper respiratory tract or the tracheal-bronchial area. Most of the submicron particles readily reach the alveolar sacs and of these, about 30% are retained in the alveoli. The remainder are exhaled with the expired air. Toxic Responses The toxicity of inhaled chemicals may be classified in many ways, i.e., in relation to the toxic mechanism involved, the response of the body, the dosage required to produce poisoning, the physical properties of the agents, etc. For industrial hygiene purposes, though, the most useful means of classification is according to the response of the body to toxic agents as described by Dr. H. F. Smyth, Jr. (1) 1. Chronic Toxicity - The most dangerous effect of some substances is a progressive systemic in fury, increasing in severity with continuing inhalation. Benzene, carbon disulphide, carbon 2-3 ARD 002706 tetrachloride and lead are the most familiar examples...Close medical supervision is required for the safe use of these substances. The standard for chronic toxic substances should refer to the time-weighted average concentration throughout a working day. Brief peaks of a few times a standard have no significance save as they increase the average. 2. Acute Toxicity - Some substances do not produce injury progressing with repeated inhalation. Such systemic injury as they may cause takes place as a result of one excessive inhalation or not at all. Familiar examples are carbon monoxide and hydrogen cyanide... 3. Narcosis - The most dangerous effect of some substances is narcosis, which becomes anesthesia in its extreme stage. At a rather low concentration, they induce accidents by impairing judgment and delaying reaction time. Familiar examples are ethyl alcohol, ethyl ether and gasoline... 4. Irritation The most dangerous effect of some substances is irritation. Eye, nose and throat are irritated at a low concentration, the bronchi at a higher concentration, and fatal lung edema may be the result of inhaling an extreme concentration. The aldehydes, halogens and acids, are familiar examples. Highly odorous substances may also be considered in this category... 5. Asphyxiation - Some substances are inert in the body and can injure only by asphyxias at ex tremely high concentrations, excluding the oxygen of the atmosphere. Familiar examples are the fluorochloro refrigerants... 6. Fume Fever - The most important effect of some substances is a transient influenza-like a con dition known as fume fever. A familiar example is zinc oxide fume... 7. Allergy - Some substances are known to sensitize an appreciable portion of exposed workmen. They may produce distressing and menacing asthma-like attacks when a sensitized person inhales a low concentration. Examples are ethylenediamine, and diisocyanates. At this time, there is no rational experimental basis far defining a concentration which will not sensitize a susceptible person, or one to which most previously sensitized workmen will respond... Interpretation of Analyses Considerable care and study is required for the proper interpretation of the results of atmospheric tests for hazardous materials. Not only must the toxic nature of the material and the atmospheric levels found be taken into account but aiso the length of the employee's exposure to the toxic materials and the methods used to collect and analyze the air sample. The latter are particularly important in relation to respiratory irritants since most sampling techniques give an integrated average concentration over the sampling period. Thus, no information is furnished about the peak levels. In many instances, peak levels causing intense respiratory irritation may exist for short periods of time whereas the sample taken over a cycle of operation shows an average concen tration well below the threshold limit. Obviously to interpret these results as proof of safe and satisfactory conditions is erroneous unless some method is devised to record the momentary peaks. In such instances more weight must be given to the degree of physiologic irritation experienced than to the concentration figure as determined by an integrated sample. Broad Line Between Safe and Harmful There is often the temptation to use threshold limit values to sharply differentiate be tween safe and unsafe atmospheric levels. Threshold limit values cannot be used for this purpose. 2-4 ARD 002707 Although they represent those concentrations according to the best available information which are believed to be safe for repeated 8-hour daily exposures, they cannot provide a fine line between safe and dangerous levels. The normal biological variation in the response of individuals to toxic agents precludes this. , To illustrate how it is intended that the threshold limits be used, assume that the aver age exposure for a group of employees to lead fume is found to be 0.22 mg/m3. One would not ordi narily recommend costly local exhaust systems to reduce the exposure to 0.20 mg/m3, the threshold limit value for lead. Instead, a return visit should be made to the location, and if the results of the second study are essentially the same as before, recommendations should be made to observe these workmen clinically at four to six month intervals for evidence of lead absorption. If blood and urine values were above normal levels, then control measures would be indicated. On the other hand, if weighted exposures were above 0.50 mg/m^ during the first study, control measures would have been recommended immediately and without hesitation. In other words, a few milligrams or parts per million below the threshold limit value does not necessarily mean the environment is safe nor would a dangerous situation exist with certainty if the threshold limit is exceeded slightly. A great deal of judgment is necessary in determining the exact cut-off point above which control measures should be instituted. It must be emphasized again that the threshold limits are designed to serve as guides only. ' Short Duration Exposures Another important aspect of the threshold limit values is that they refer to a weighted average concentration for an 8-hour work shift exposure rather than a maximum concentration that cannot be exceeded even momentarily. For example, the threshold limit for lead is 0.2 mg. per cubic meter of air for an 8-hour period. Accordingly, a level of 0.4 mg. per cubic.meter would be permissible for four hours, 0.8 for two hours. There is obviously a limit, though, to which the weighted average exposure principle can be applied. The following general rules apply for brief exposures: concentrations of respiratory irritants should not substantially exceed the threshold value; concentrations of substances producing narcosis should seldom exceed three times the threshold value; concentrations of substances causing asphyxiation, fume fever or allergy should not substantially exceed the threshold limit value; and concentrations of substances causing acute and chronic poisoning should not exceed the threshold limit value by a factor of more than eight. Threshold Limit Values Tables 2.2-2.9 list most of the commonly used toxic chemicals. These tables show the threshold limit values for both long and short time exposures. The 8-hour weighted averages re ferred to in Tables 2.2-2.9 are calculated as mentioned above. Ingestion Although, in industry, ingestion is generally secondary to inhalation as a portal of entry for toxic material it is, nevertheless, important. In areas where highly toxic materials are involved, carelessness and poor hygienic practices can lead to the ingestion of significant quantities of the material and are to be avoided. The skin should always be kept clean of highly toxic materials to prevent the transfer of them from hand to mouth. Care should be taken to eliminate the possibility of contaminating lunches, tobacco, and chewing gum, etc. Storing and eating of lunches in areas where highly toxic materials are processed should be prohibited. 2-5 ARD 002708 # Threshold Limit Values of Airborne Contaminants AND INTENDED CHANGES Adopted By AC6IH For 1970 PREFACE THRESHOLD LIMIT VALUES FOR 1970 Threshold limit values refer to airborne concentrations of substances and represent conditions under which it is be lieved that nearly all workers may be repeatedly exposed day after day without adverse effect. Because of wide varia tion in individual susceptibility, however, a small percentage of workers may experience discomfort from some substances at concentrations at or below the threshold limit, a smaller percentage may be affected more seriously by aggravation of a pre-existing condition or by development of an occupa tional illness. Simple tests are now available (J. Occup. Med. 9, 537, 1967; Ann. N.Y. Acad. Sci., 151 Art. 2, p. 968, 1968) that may be used to detect those individuals hypersusceptible to a variety of industrial chemicals (respiratory irritants, hemolytic chemicals, organic Isocyanates, carbon disul fide). These tests may be used to screen out by appropriate Job placement the hyperreactive worker and thus in effect improve this "coverage" of the TLVs. Threshold limit values refer to time-weighted concentra tions for a 7 or 8-hour workday and 40-hour workweek. They should be used as guides in the control of health hazards and should not be used as fine lines between safe and dangerous concentrations. (Exceptions are the substances listed in Appendices A and E and those substances designated with a "C" or Ceiling value, Appendix C.) Time-weighted averages permit excursions above thp limit provided they are compensated by equivalent excur sions below the limit during the workday. In some instances it may be permissible to calculate the average concentration for a workweek rather than for a workday. The degree of permissible excursion is related to the magnitude of the threshold limit value of a particular substance as given in Appendix C. The relationship between threshold limit and permissible excursion is a rule of thumb and in certain cases may not apply. The amount by which threshold limits may be exceeded for short periods without injury to health depends upon a number of factors such as the nature of the contaminant, whether very high concentrations - even for short periods - produce acute poisoning, whether the ef fects are cumulative, the frequency with which high con centrations occur, and the duration of such periods. All factors must be taken into consideration in arriving at de cision as to whether a hazardous condition exists. Threshold limits are based on the best available informa tion from industrial experience, from experimental human and animal studies, and, when possible, from a combination of the three. The basis on which the values are established may differ from substance to substance; protection against impairment of health may be a guiding factor for some, where as reasonable freedom from irritation, narcosis, nuisance or oilier forms of stress may form the basis for others. The committee holds to the opinion that limits based on physical irritation should be considered no less binding than those based On physical impairment. There Is increasing evidence that physical irritation may initiate, promote or accelerate physical Impairment through interaction with other chemical or biologic agents. In spite of the fact that serious injury is not believed likely as a result of exposure to the threshold limit concen trations, the best practice la to maintain concentrations of all atmospheric contaminants as low as is practical. These limits are Intended (or use in the practice of in dustrial hygiene and should be interpreted and applied only by a person trained in this discipline. They are not intended for use, or (or modification for use, (1) as a relative index of hazard or toxicity, (2) in the evaluation or control of community air pollution or air pollution nuisances, (3) in estimating the toxic potential of continuous uninterrupted exposures, (4) as proof or disproof of an existing disease or physical conditions, or (5) for adoption by countries whose working conditions differ from those in the United States of America and where substances and processes differ. Ceiling vs Time-Weighted Average Limits. Although the time-weighted average concentration provides the most satisfactory, practical way of monitoring airborne agents for compliance with the limits, there are certain substances for which it is inappropriate. In the latter group are sub stances which are predominantly fast acting and whose threshold limit is more appropriately based on this particu lar response. Substances with this type of response are best controlled by a celling "C" limit that should not be exceeded. It is implicit In these definitions that the manner of sampling to determine compliance with the UmitB for each group must differ; a single brief sample, that is applicable to a "C" limit, is not appropriate to the time-weighted limit; here, a sufficient number of samples are needed to permit a time-weighted average concentration throughout a complete cycle of operations or throughout the work shift. Reprinted with permi ion from the American Conference of Governmental Industri il Hygienists. ii i. ARD 002709 Whereas the ceiling limit places a definite boundary which concentrations should not be permitted to exceed, the timeweighted average limit requires an explicit limit to the ex cursions that are permissible above the listed values. The magnitude of these excursions may be pegged to the magni tude of the threshold limit by an appropriate factor shown in Appendix C. It should be noted that the same factors are used by the Committee in making a judgment whether to include or exclude a substance for a "C" listing. "Skin" Notation. Listed substances followed by the de signation "Skin" refer to the potential contribution to the over-all exposure by the cutaneous route including mucous membranes and eye, either by airborne, or more particu larly, by direct contact with the substance. Vehicles can alter skin absorption. This attention-calling designation is intended to suggest appropriate measures for the preven tion of cutaneous absorption so that the threshold limit is not invalidated. Mixtures. Special consideration should be given also to the application of the TLVs in assessing the health hazards which may be associated with exposure to mixtures of two or more substances. A brief discussion of basic considerations involved in developing threshold limit values for mixtures, and methods for their development, amplified by specific examples are given in Appendix D. Nuisance Dusts, in contrast to fibrogenic dusts which cause scar tissue to be formed in lungs when inhaled in ex cessive amounts, so-called "nuisance" dusts have a long history of little adverse effect on lungs and do not produce significant organic disease or toxic effect when exposures are kept under reasonable control. The nuisance dusts have also been called (biologically) "inert" dusts, but the latter term is inappropriate to the extent that there is no dust which does not evoke some cellular response in the lung when inhaled in sufficient amount. However, the lung-tissue re action caused by Inhalation of nuisance dusts has the follow ing characteristics: 1) The architecture of the air spaces remains intact. 2) Collagen (scar tissue) is not formed to a significant extent. 3) The tissue reaction is potentially re versible. Excessive concentrations of nuisance dusts in the work room air may seriously reduce visibility (iron oxide), may cause unpleasant deposits in the eyes, ears and nasal pass ages (Portland Cement dust), or cause injury to the skin or mucous membranes by chemical or mechanical action per se or by the rigorous skip cleansing procedures necessary for their removal. A threshold limit of lOmg/M^, or 30 mppcf, of total dust < 1% S1O2, whichever is less, is recommended for sub stances in these categories and for which no specific thres hold limits have been assigned. This limit, for a normal workday, does not apply to brief exposures at higher concen trations. Neither does it apply to those substances which may cause physiologic impairment at lower concentrations but for which a threshold limit has not yet been adopted. Some "inert" particulates are given in Appendix D. Simple Asphyxiants - "Inert" Gases or Vapors, A number of gases and vapors, when present in high concentrations in air, act primarily as simple asphyxiants without other signi ficant physiologic effects. A TLV may not be recommended for each simple asphyxiant because the limiting factor is the available oxygen. The minimal oxygen content should be 18 percent by volume under normal atmospheric pressure (equivalent to a partial pressure, p02 of 135 mm Hg). Atmos pheres deficient In 03 do not provide adequate warning and most simple asphyxiants are ordorless. Several simple asphyxiants present an explosion hazard. Account should be taken of this factor In limiting the concentration of the asphyxiant. Specific examples are listed in Appendix E. Physical Factors. It is recognized that such physical factors as heat, ultraviolet and ionizing radiation, humidity, abnormal pressure (altitude) and the like may place added stress on the body so that the effects from exposure at a threshold limit may be altered. Most of these stresses act adversely to increase the toxic response of a substance. Although most threshold limits have built-in safety factors to guard against adverse effects to moderate deviations from normal environments, the safety factors of most substances are not of such a magnitude as to take care of gross devia tions. For example, continuous work at temperatures above 00F or over-time extending the workweek more than 25%, might be considered gross deviations. In such Instances Judgment must be exercised in the proper adjustments of the threshold limit values. "Notlce of Intent." At the beginning of each year, proposed actions of the Committee for the forthcoming year are issued in the form of a "Notice of Intent." This Notice provides not only an opportunity for comment, but solicits suggestions of substances to be added to the list. The suggestions should be accompanied by substantiating evidence. The list of Intended 1 Changes follows the Adopted Values in the TLV booklet. As Legislative Code. The Conference recognizes that the TLVs may be adopted in legislative codes and regulations. If so used, the intent of the concepts contained in the Preface should be maintained and provisions should be made to keep the list current. These values are reviewed annually by the Committee on Threshold Limits for revision or additions, as further information becomes available. Reprint Permission. This publication may be reprinted provided that written permission is obtained from the Secre tary-Treasurer of the Conference and that it be published in its entirety. ARD 002711 6ub*teace ADOPTED VALUES (In Alphabatlcal Order) fp"** Abate ............................................................... , Acetaldehyde ................................................. Acetic acid..................................................... . Acetic anhydride.........................................., Acetone.............. ........................................... .. Acetonitrile ................................................... . Acetylene.......................................................... , Acetylene dlchlorlde, eee 1, 3- Dlchlorocthylens..................................... , Acetylene tetrabromide............................ Acrolein .......................................................... , Acrylamide-Skin........................................... Acrylonltrtle.-Sktn......................................... Aldrln-Skln..................................................... . Allyl alcohoi-Skin......................................... Ally 1 chloride................................................. , I Allyl glycidyl ether (AGE)....................... , Allyl propyl disulfide................................ , Alundum (AI2O3).........................................., 2-Amlnoethanol, eee Ethanolamlne ..., 2-Amlnopyrldlne.........................................., ' Ammonia.......................................................... , Ammonium suUamate (Ammate)............, n-Amyl acetate ............................................ . ec-Amyl acetate ........................................, Anlllne-Skln................................................... , Anlsldlne (o, p>leomers)-Skln................ , Antimony & compounds (as Sb).............. . ANTU (alpha naphthyl thiourea)............, Argon ..............................................................., Arsenic 4 Compounds (as As)................ , Arsine................................................ .............. Azlnphos-methyl-Skin............... Barium (soluble compounds)................., ' Benzene (benzol)-Skln .............................. Benzldlne-Skln..............................................., p-Bcnzoqulnone, ees Qulnone................. Benzoyl peroxide.......................... ............... , Benzyl chloride................... ........................ , Beryllium........................................................ , Biphenyl, see Diphenyl ............................ Dlaphenol A, eee Dlglycldyl ether ...., Boron oxide ................... ............................... , Boron tribromide ........................................ Boron trifluoride ........................................ Bromine............................................................. Bromine pcnla/luorlde ............................ Bromoforra-Skln.......................................... Butadiene (1, 3-butadiene)........................ Dutanclhiol, eee Butyl mercaptan ...., 2-Butanone...................................................... 2-Butoxy ethanol (Butyl Celloeolve) - Skin ............................................................... Butyl acetate (n-butyl acetate) .............. . __ 200 10 ft 1,000 40 E -1 0.1 -ao 2 1 10 2 --0.6 50 -100 125 ft ---E -0.0ft .. 25 .. --- 1 .. --- 1 1 0.1 0.1 o.s 1,000 -200 50 160 15 360 . 25 20 3,400 70 "* -14 0.2ft 0.) 45 0.2ft ft 3 45 12 D -- 2 35 15 625 650 19 0.5 O.S 0.3 -0.6 0.2 0.2 0.5 60 A> -- 5 5 0.002 -- -15 10 3 0.7 0.7 6 2, 200 -690 240 710 Part* of vapor or sad par million parts of containlimed air by volume at 1SC and 100 mm. Kg prassurt. Approaimats milligram* of parttcuUU par oifale m*tsr of air. ** S Notice of Intended Chinpi Capital Utiero refer to Appeodlcee. Sebilintt scc-Butyl acetate ........................................ tert'Butyl acetate........................................ Butyl alcohol ..................................... .. sec*Duty 1 alcohol ........................................ tert-Dutyl alcohol........................................ C Butylamlne-Skin .......................................... C tert-Butyl chromate (as C1O3) - Skin . n-Butyl glycidyl ether (BGE)................... * Butyl mercaptan .......................................... p-tert-Butyltoluene..................................... Cadmium (Metal dust and soluble salts) *C Cadmium oxide fume (as Cd) ........ Calcium carbonate ..................................... Calcium arsenate ........................................ Calcium oxide ............................................... 44 Camphor (Synthetic)................................... Carbaryl (Sevln ) ................................... Carbon black ................................................. Carbon dioxide............................................... Carbon dlBuUlde-Skin................................. Carbon monoxide..................... .................... Carbon tetrachloride-Skin........................ Cellulose (paper fiber)............................... Chlordane-Sktn ............................................ Chlorinated camphene-Sktn ..................... Chlorinated diphenyl oxide ..................... * Chlorine .......................................................... . Chlorine dioxide .......................................... C Chlorine trifluoride ................................... C Chloroacetaldehyde ................................... <-ChloroacetopheHone (phcnacyl- chlorlde)............ .. Chlorobenzene (monochlorobenzene) .. 0-Chlorobenzylldene maloiionltrile (OCBM)........................................................ Chlorobromomethane ................................. 2-Chloro-l, 3-butadiene, see Chloroprene ............................................... Chlorodiphenyl (42% Chlorine) - Skin . Chlorodlphenyl (54% Chlorine) - Skin . 1-Chloro, 2, 3-epoxypropane, see Eplchlorhydrin.......................................... 2-Chloroethanol, see Ethylene chlorohydrin .......................................... Chloroethylenc, see Vinyl chorlde ... C Chloroform (trichloromcthane) ............ 1-Chloro-l-nitropropane.......................... Chloropicrln ................................................. Chloroprene (2-chloro-l, 3-txitadiene) -Skin ............................................................. Chromic acid and chromates (as Cr03) Chromium, sol. chromic, chromous salts as Cr................................................. Metal & insol. salts............................... Coal tar pitch volatiles (benzene soluble fraction) anthracene, BaP, phenanUirene, acridine, chrysene, pyrene) ........................................................ * 1970 Addition Motlci of InUndid Cbangca ppm4* 200 200 100 150 100 5 ,,,, 50 0.5 10 __ " 2 __ __ ,000 20 50 10 -__ __ 1 0.1 0.1 1 0.05 75 0.05 200 so 20 0.1 25 __ "" 950 950 300 450 300 15 0.1 270 1.5 60 0.2 0.1 D 5 -- 5 3.5 9,000 60 55 65 D 0.5 0.5 0.5 3 0.3 0.4 3 0.3 350 0.4 1,050 1 0.5 240 100 0.7 90 0.1 0.5 1 0.2 V. Subtltiut Cobalt, metal fume li dust ...................... Copper fume.................................................... Dusts and Mists.................................... .... Corundum (AI2O3)................................. .. Colton dust (raw)........................................... Crag1?' herbicide ......................................... Creaul (alt isomers) - Skin...................... Crotonaldehyde ............................................. Cumene-Skin ........................................... Cyanide (as CN)-Skin.................................. * Cyanogen ............................................................ Cyclohexane .................................... ................ Cyclohexanone ................................................ Cyclohexene ............................... ..................... Cyclopentadiene............................................. 2, 4-D................................................................ DDT-SKui ......................................................... DDV P, see Diclilorvon.............. Decaborane-Skin .. . ........................ .... Demeton-Skin ........................................ Dlacetunc alcohol(4-hydroxy- 4-niHhy l-2-pentanone).......................... 1. 2-Diaminoethane, see Ethylene- diamine ........................ ... Diazomethune ................................................ Dlboram.*............................................................ C 1, 2-Dibromuethane (ethylene dibronmle)-Skln ...................................... Otbutyl phosphate ......................................... DibutyljjhUiaijte ........................................... C Dtchlor)acetylene......................................... C o-Dichlornbenzene ......... ........................ p-Dichloubenzene .............. ....................... Dichlorodifluoromethane.......................... 1, 3-l)ichloro-5, 5-dimethyi hydantoin 1, 1-Dichloroethanc.................................... 1, 2-Dichluroethane ..................... ............. 1, 2-DlchluroeUiylene ............................... C Dtchloroethyl elher-Skin.......................... Dichioromethane, see Methylene- chloride ......................................................... DuhloronionoiluoromcUiane................. .. C 1, l-Dichlnru-l-nitroeUiane................... 1, 2-Dlchloroprop.ine, see Propvleneduhlortde ...................................... Dull lorotetrufluoroe thane........................ Dlchtorvos (DDVP)-Skln .......................... Dieldrtn-Skin................................. .. DleUiylamlne ............................................. I)it-thy laniino ethanol-Skin................. 'C Diethyleue trtamlnc-Skln ........................... Diethylellicr, see Ethyl ether Dllluorodibroinomethane .......................... C Dlglycldyl ether (DOE)............................... Ddiydroxybenzene, see Hydroqulnone . Dnsobutyl ketone........................................... Dlisopropylamlne-Skin ................... ppm4) .. ------ 5 2 50 -10 300 50 50 300 75 .. 0.05 so -0.2 0.1 25 1 -0.1 50 75 1,000 -100 50 200 15 .1,000 10 -1,000 __ __ 25 10 10 .. 100 0.6 -- 60ft |910 Addition Sea Nod lea ol Inlandad Changes -*/>> 0.1 0.1 1 D 1 15 22 6 245 5 -1,050 200 200 1,015 200 10 1 ... 0.3 0.1 240 .. 0.4 0.1 190 5 5 0.4 300 450 4,950 0.2 400 200 790 90 4, 200 00 7,000 1 0.25 75 50 42 __ 660 2.6 __ 290 20 ARD 002712 Swbdancc . Dlinethoxy methane, see Methylal .... Dimethyl acctamlde-Skln .......................... Dlmethylamlne............................................... Dlmelhylamlnobenzene, see Xylldene . Dlincthylanlllne (N-dlmethylantllne)- Skln ............................................................. Dlmethylbenzens, see Xylene ........ Dimethyl 1, 2-dlbromo-2, 2-dl- chloroethyl phosphate, (Dlbrora) ... Dlmethyliormamlde-Skln ........................ 2, 6-Dlmothylheptanone, see Dllsobutyl ketone .................................. 1, 1-Dlmelhylhydrazlne-Skln................. Dlmethylphthalate ........................................ Dlmethylsulfate-Skln ................................. Dlnltrobenzene (all lsomers)-Skln .... Dlnltro-o-creaol-Sktn ............................... Dlnltrotolucne-Skin .................................... Dloxane (Dlcthylene dloxlde)-Skln .... Diphenyl .......................................................... Diphenyl amine ............................................. Dlphenylmethane dllaocyanate (aea Methylene blsphenyl laocyanate (MDI)............................................................. Dlpropylene glycol methyl ether-Skln . Dl-aec, octyl phthalate (DI-2- ethylhexylphthalate)................................. Emery ............................................................... * Endosullan (Thlodan )-Skln .............. Endrln-Skln ................................................. .. Eplchlorhydrln-Skln ................................... EPN-SkLn ........................................................ 1, 2-Epoxypropane, aee Propylene- oxide ............................................................. 2, 3-Epoxy-l-propanol, aee Clycldol . Ethane ............................................................... Ethanethlol, aee Ethylmercaptan.......... Eihanolamlnc................................................. 2-Elhoxyethanol-Skln................................. 2-Ethoxyethy)acctate ICeltosolve acctate)-Skln ............................................. Ethyl acetate ................................................. Ethyl acrylate-Skln ...................................... Ethyl alcohol (ethanol)............................... Ethyiamine ...................................................... Ethyl eec-amyl ketone (5-methyl- 3-hcpMnone) ............................................. Ethyl benzene ............................................. Ethyl bromide ............................................... Ethyl butyl ketone (3-Heptanone).......... Ethyl chloride ............................................... Ethyl ether...................................................... Ethyl formate ;................... ............. .. Ethyl mercaptan .......................................... Ethyl silicate................................................. Ethylene ............................................... .. Ethylene chlorohydrln-fikln...................... ,pna! 10 10 5 .. 10 .. 0.6 1 __ 100 0.3 100 __ .. .. 5 E 3 200 100 400 25 1,000 10 ` 25 100 200 50 1,000 400 100 0.5 100 E 5 1870 Addition See Notice ol Intended Cbaajee 35 18 __ 25 3 30 __ 1 5 5 1 0.2 1.5 380 1 10 -600 5 D 0.1 0.1 18 0.5 __ __ __ _. 6 740 540 1.400 100 1,900 18 130 435 890 230 2,600 1,200 300 1 850 -16 SubUxnce Ethylenediamute ........................................ . Ethylene dibromide, see 1, 2- DibrumuethaiH* ...................................... . Ethylene dichluride, see 1, 2- Diehlorocthaiie ................................. , C Ethylene glycol duiilrate and/or Ntlroglycertn-Skm ............................... . Ethylene glycol monomethyi ether acetate, see Methyl cellosolve acetate ...................................................... Ethylene imine-Sktn................................. . Ethylene oxide ............................................. . Ethylidinc chloride, see 1, 1-Dichloroethane .......................................... , N-Ethyimorptioline-Skin ........................ . Ferbam ........................................................... . Ferrovanadium dust................................. , .Fibrous glass ............................................. . Fluoride (as F) ........................................... Fluorine ........................................................ . Fluorotrlchloromethane ..................... . *C Formaldehyde .......................................... .. . Formic acid................................................. . FurluraJ-Skin............................................... . Furfuryl alcohol ........................................ . Gasoline ....................................................... . Glycerine mist............................................ . Glycidol (2, 3-Epoxy-l-propanol) ... . Glycol monoetfiyl ether, see 2- Ethoxyethanol.......................................... . Graphite, (Synthetic)................................. . Guthiun, see Azinphosmethyl ...... . Gypsum........................................................ .. . Hafnium.............. ........................................... . Helium ............................................................. . Heptachlnr-Skin.......................................... . Heptane (n-heptane) ................................. . Ilexachloroetiiane-Skin............................ . Hexachloronaphthalene-Skln................. . Hexane (n-hexane)...................................... . 2-Hexanone .................................................... . Hexone (Methyl l6obutyl ketone)............ . sec-Hexyl acetate...................................... . Hydrazine-Skin .......................................... . Hydrogen ........................................................ . Hydrogen bromide..................... ................ . C Hydrogen chloride...................................... . Hydrogen cyamde-Skin............................ . Hydrogen fluoride...................................... . Hydrogen peroxide ................... .. , Hydrogen sclenide..................... ................ . Hydrogen sulfide........................................ . Hydroquinone............................................... indene ............................................................. . ppB> 10 -- .. 0.2d> -- 0.5 50 -- 20 ---- 0.1 1,000 5 5 5 50 --50 -----E -500 1 -500 too 100 50 1 E 3 5 10 3 l 0.05 10 10 25 __ __ -- ._ 1 90 __ 94 15 1 D 2.5 0.2 5,600 6 9 20 200 A3 1) 150 -D -D 0.5 -0.5 2,000 10 0.2 1, 800 410 410 300 1.3 -10 7 11 2 1.4 0.2 15 2 45 d) An atmospheric concentration id not more Uaa 0.02 ppm, or poraonal protection may be Mceeaary to avoid bcadadM, 1870 Addition See Notice ol Intended Change VI lubtlilM liuiium and compounds, as In................. C Iodine .................................................................. Iron oxide fume ............................................. Iron salts, soluble, as Fe........................ Isoamyl acetate ............................................. Iso.tmyl alcohol ............................................. Lsubutyl acetate ............................................. Isobutyl alcohol............................................. isophurone ............ .......................................... Isopropyl acetate ........................................... Isopropyl alcohol ........................................... Isopropyl.umne ............................... Isopropytether .......................... .. Isopropyl glycldyl ether (1GE) ............... Kaolin ................................................................ Ketene ................................................................ Lead..................................................................... Lead arsenate ............................................... Limestone......................................................... Lindane-Skin ................................................. Lithium hydride................... ......................... L. P. O. (Liquified petroleum gas) .... Magnesite ......................................................... Magnesium oxide lume............................... M.ilathion-Skin ............ ................................ Maleic anhydride.......................................... C Manganese and compounds, as Mn ,... Marble................................................................ * Mei rui y-Skm.................................................. Mejt ui y (oiganir rumpounds)-Skln . . . Mesityl oxide .................................................. Methane ........................................................... Methane! Innl, see Methyl mercaptan.. Melhoxyr hlor ............................................. 2-Mi.ihox; ethanol, see Methyl relic .solve...................................................... Methyl acetate............................................... Methyl acetylene (piopyne)........................ Melhvl ,u etylene-propadiene mixture (MAPP)........................................................... Methyl acrylate-Skln.................................... Melhylai (dimelhoxymeihane) ................. Methyl alcohol (methanol) ........................ Metliytamtne .................................................. Methyl amyl alcohol, see Methyl isobutyl carbmol........................................ Methyl isoamyl ketone............................... Methyl (n-amyl) ketone (2-Heptanone). C Methyl bronude-Skin.................................... Methyl butyl ketone, see 2-Hexanone . Methyl rellusolve-Skln............................... Methyl cellosnlve acetate-Skln.............. *C Methyl ctilorlde ............................................. Methyl chloroform........................................ Methylcyclohexane........................................ Methylcyclohexanol................. .................... ppmB> .. 0.1 .. . 100 too 150 too 25 250 400 5 SQ0 so .. 0.5 .. -.. -- 000 -- 0.35 --- -- 25 E - 200 000 ,000 10 ,000 200 10 100 100 20 ,, 25 25 100 350 500 100 0.1 1 10 525 360 700 300 140 950 980 12 2,100 240 D 0.9 0.2 0.15 D 0.5 0.025 1,600 D 15 15 1 5 D 0.1 0.01 100 ** IS 610 1,650 1,800 35 3,100 260 12 475 465 80 60 120 210 1,900 2,000 470 1870 Addition * See Notice oI Intended Chanfe* ARD 002713 ppm** o-Melhylo clnhexanonc-8kin................... Mtihyl rlhjI ketone (MEK), see 2-Duianont* ................................................. Methyl formate ............................................ Methyl iodide - Skin................................... Methyl isobulyl carbmol-SkJn .............. ' Methyl isobulyl ketone, see llexone ... Methyl isocyanate - Skin.......................... * Methyl mercaptan....................................... Methyl methacrylate................................... Methyl propyl ketone, see 2-Pentanone C Methyl silirate.............................................. C u Methyl styrene.......................................... C Methylene btaphenyl isocyanate (MOI). Methylene chloride (dichloromethane). Molybdenum (soluble compounds).......... (Insoluble compounds) ... Monomethyl aniline-Skln.......................... C Monomethyl hydrazlne-Skln..................... Morplioline-Skin....................... .................... Naphtha (coal tar) ........................................ Naphthalene'...................................................... p -Naphthylamine ........................................ Neon.................................................................. Nickel carUmyl ............................................ Nickel, metal and soluble empds, as Nl Nu oUne-Skin......... ...................................... Nitric add........................................................ Nit i tc oxide..................................................... j>- Nitruamlinc-Sktn................ .................... Nit robi'iucm'-Skin........................................ p-Nllruihlorobenzene-Skln ................... Nitroclhane............................ :....................... Nitrogen............................................................ Nitrogen dioxide............................................ Nitrogen trifluoride ................................... Nitroglycerin-Skin........................................ Nitromethane................................................. -1-Nitropropane .............................................. 2-NItropropane............................................... N-Nitrosodimethylamine (dimethyl- nltrosoamine)-Skln................................. Nltrololuenc-Skln..................... .. NUrotrlchloromethane, see Chloroplcrin.............................................. Nitrous oxide................................................. Ociachloronaphthalene-Skin ............ * Octane................................................................. * Oil mist, particulate................................... * Oil mist, vapor ..................... Osmium tetroxide................................. .. Oxalic acid...................................................... * Oxygen difluoride.......................................... Oione................................................................. Paraquat-Skin................................. ................ 100 100 5 25 0.02 o.s 100 5 100 0.02 500 .. 2 0.2 20 100 10 -E 0.001 --2 25 1 1 -100 E 5 10 0.2 100 25 25 __ 5 E -400 __ 0 AS --- 0.05 0.1 -- h) A* templed by method lhal doc* not collect vapor. I) According to analytically determined composition. * 1910 Addition * See Notice of Intended Change* 400 250 28 100 0.05 1 410 30 4B0 0.2 1,740 5 15 9 0.35 70 400 50 A* .. 0. 007 1 0.5 5 30 6 5 1 310 .. 9 29 2 250 90 90 A* 30 0.1 1,900 5h 0.002 1 0.1 0.2 0* 5 Subtiaorc Parathiun-Skin............................................... Pcntaborane .................................................... Pentachloronaphthaiene-Skln ................. Pentachlorophenol-Skin............................ Pentaerythrltol............................................... Pentane................................. ........................... 2-Pentanone .................................................... Perchloroethylene........................................ Perchloromelhyl mercaptan................... Perchloryl fluoride...................................... * Petroleum Distillates (naphtha)............ Phenol-Skin...................................................... p-Phenylene diamine-Skin........................ Phenyl ether (vapor)................................... Phenyl ether- Diphenyl mixture (vapor) Phenylcthylene, see Styrene................... Phenyl glycidyl ether (PGE)................... Phenylhydraiine-Skin ................................. Phosdrin (Mevinphos llM-Skln................. Phosgene (carbonyl chloride)................. Phosphine........................................................... Phosphoric acid............................................. Phosphorus (yellow).................................... Phosphorus pcntachloride........................ Phosphorus pentasuliide .......................... Phosphorus trichloride ............................. Pidhailc anhydride ................... .... Picric acid-Skin ........................................ pival "*'(2-Pivalyl-l, 3-indandlone) ... Plaster of Paris ................... Platinum (Soluble Salts) as Pt.............. .. Polytetra/luoroethylene decomposition products................................. ....................... Propane................................. ........................... (i Propiolactone............................................. Propargyl alcohol-Skin ............................ n-Propyl acetate ........................................... Propyl alcohol............................................... n-Prupyl nitrate ................................... .. Projiylene dichloride .......................... Propylene Inune-Skln................................. Propylene oxide............................................. Propyne, see Methylacetylene............... Pyrethrum ...................................................... Pyridine ........................................................... Qulnone............................................................. RDX-Skm ......................................................... Rhodium, Metal fume and dusts, as Rh Soluble salts............................................... Runnel........................................ .. Rotenone (commercial) ............................. Rouge .................................................................. Selenium compounds (as Se)................... Selenium hexafluoride ............................... Silicon carbide............................................... 1) According to analytically determined composition. Capital Utters rslsr to Appsndlcea. I#70 Addition ** See Notice ol Intended Changes .. --0.005 --_ - 500 200 100 0.1 3 0 A3 --5 1 1 10 -5 0.1 -0- .3 -* 0.5 --2 -- -- _ E - 1 200 200 25 75 2 100 5 ---.---.0.1 ----- .0. .05 1,/M1 b| 0. 1 0.01 0.5 O.S L) 1,500 700 670 0.6 .1.3.5 19 0.1 7 7 60 22 0. 1 0.4 0.4 1 0.1 1 1 3 12 0.1 0.1 D 0.002 A2 Al 840 500 110 350 5 240 5 15 0.4 1.5 0.1 0.001 10 5 D 0.2 0.4 D bubiiMict Silver, metal and soluble compounds . Sodium flooroaretate (1080)-Sktn.......... Sodium hydroxide ......................................... Stibme................................................................. 0.1 Starch .......................................................... .. Stoddard solvent ........................ 200 Strychnine.................................................... .. 'C Styrene monomer (ptienylethylene) ... 100 Sucrose........................ Sulfur dioxide.................................... ............. Sulfur hexafluoride........................ .. S 1,000 Sulfuric acid..................................................... Sulfur monochloride................. Sulfur peutafluorlde ........................ .. Sulfuryl fluoride ........................................... 1 0.025 5 Systox, see Demeton .............. .. 2, 4, ST............................................................ Tantalum.................................................... .. TEDP-Skui ....................................................... Teflon " decomposition products.......... Tellurium ................................................. .. Tellurium hexafluoride ............................. 0. 02 TEPP-Skui ....................................................... C Terphenyls ....................................................... ), I, 1, 2-TetrachIoro-2, 2-dl(luorocthune ................................................ 500 1, 1, 2, 2-Tctrachlom-1, 2-dl- (luorocthajic................................................ 500 1, 1, 2, 2-I elrachloroeUione-Skln ... 5 TctrachloroeUiylene, see Per- chloroethylcne ............................... Teirarhlnromcthane, see Carbon tetrachloride ............................................. -- Tetrachloronaphthalene-Skin ................. - Tetraethyl lead (as Pb)-Skln .................... -- Telrahydnduran ........................................... 200 Teiramethyl lead (as Pb)-Skln ............ -- Tetramethyl succiuomtrile-Skln .......... 0.5 Tetnuntroincthane ...................................... 1 Telryl (2, 4, 6-truiilrophenyl- methylnitramlnel'Skin ........................ -- Thallium (soluble compounds)-Skin as T) Ibtram ....................................................... Tin (inorganic empds, except Snllg amJ SnC>2) ..................................................... Tin (organic empds).................................... '' Tin oxide ......................................................... ** Titanium dioxide........................................... -- Toluene (toluol) ............................................. 200 C Tolucne-2. 4-diisocyanate ...................... 0.02 o-Toluidme-Skin ............................... 5 Toxaphene, see Chlorinated camphene.............. - Tributyl phosphate ................... - 1, 1, 1-TrtchloroeUiane, see Methyl chloroform.............................. - 1, 1, 2-Trlchloroethane-Skln .............. 10 0.0| 0.05 2 0.5 D 1,150 0.15 0420 U 8,000 I 6 0.25 20 10 5 0.2 A2 0.1 0.2 0.05 4, 170 4, 170 35 0.100 )> 590 0.150 1> 3 1.5 0.1 5 2 0.1 D I) 750 0. 14 22 5 45 |) t or control oI gensrsl room air. Moioglc monitoring la saaantial lor paraounsl cunliol. , 1070 Addition Sec Notice ol Intended Changes vn . ARD 002714 SabxiMC Trichloroethylene........................................ Trichloronu'Uianc, see Chloroform .. TricliloronaphUialene-Skin ........... 1, 2, 3-Trlchloropropane........................ *0 -- 50 I, 1, 2-Trtchloro I, 2, 2-trilluoroeth.uic ......................... Triethylanilne ............................................... Trifluoromonobroinomethane................. 1,000 25 1,000 Trnnethyl benzene ...................................... 2, 4, 6-Truulrupficnol, see Plcric acid '2, 4, 6-TrinitrophenylmeUiylnitramine, 25 -- see Telryl................................................... Trlnilrotoluene-Skln ................................... Trlorihocresyl phosphate ........................ Trtphenyl phosphate.................................... Tungsten (i compounds, as W Soluble............ ........................................... .. Insoluble ..................................................... Turpentine ...................................................... Uramum (natural) sol. & Ineol. compounds as U........................................ C Vanadium (V2O5 dust) ............................... (V20&fume) ............................. Vinyl benzene, see Styrene...................... C Vinyl chloride ............................................... Vmylcyanidc, see Acrylonitrile............ Vuiyl toluene ........................... . -~~ "** "" 100 " *-- -- 500 100 Warfarin........................................................... Xylene (xylol)................................................. Xylldine-Skui...................... Yttrium ............................................................. Zinc chloride fume ...................................... Zinc oxide fume............ ................................ Zirconium compounds (as Zr) .............. ~~ 100 5 "" ~~ -- 535 5 300 7,600 100 6,100 120 1.5 0.1 2 1 5 560 0.2 0.5 1,300 480 0.1 435 25 1 1 5 5 Radioactivity: For permissible concentrations of radioisotopes in air, see" U.S. Department of Commerce, National Bureau of Standards, Handbook 69, "Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure," June 5, 1959. Also, see U.S. Department of Commerce National Bureau of Standards, Handbook 59, "Permissible Dose from External Sources of Ionizing Radiation/* September 24, 1954, and addendum of April 15, 1958. 1970 Addition See Notice of Intended Change* MINERAL OUSTS Subuiate SILICA Crystalline Quartz, Threshold Limit calculated Irom the formula .......................................... 250 " %SlC>2.S Cristobalite "" " Amorphous, including natural dialomaceous earth ...................................... 20 SILICATES (less than 1% crystalline silica) * Asbestos, all types ............................................ Mica........................................................................ Portland Cement .............................. Soapstone ..................................... Talc (non-asbesttform)................................... Talc (fibrous), use asbestos limit...... Tremolile, see asbestos .......................................... 20 50 20 20 -- - 5 Graphite (natural) ............................................................. 15 +* "Inert" or Nuisance Particulates 50 (or 15 mg/M3 whichever is the see Appendix D smaller) of total dust < 1% Sl02 Conversion factors mppcf x 95.9 - million particles per cubic meter particles per c. c. ) Million* of particle* per cubic loot of air, baaed on impinger sample* ruuaU by light-field technic*. 1 I) The percentage ol crystalline eillca In Uie formula, le Uie amount dclermint from airborne eamplee, except In tfcoae Inalanc** In which other methods hit been shown to be applicable. ** See Notice of Intended Changes for Mlnersl Dusts. NOTICE OF INTENDED CHANGES (for 1970) These substances, with their corresponding values, com prise those for which either a limit lias 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 (or a period of at least two years. During this time, the previously Adopted Limit will remain in effect. If, after two years no evidence comes to light that questions the appropriateness of the values herein, the values will be placed in the "Adopted** list. Documentation is available for each of these substances. Subunrc ppm 2-Aretylamlnufluorene-Skln.................... . Ally) gJyctdyl ether...................................... 4-Aminodiphcnyl-Sklr*.................................. . Ammorua ............................................................ Ammonium chlnilde lume ........................ 5 -js Bulyl lactate..................................................... Camphor (synthetic)....................................... Di.winon-Sklti.................................................. 2-N Dibulyljnnnu ethanol-Skin............... Dirtikorobi-nzl dine-Skin................................ Diethylenc tnamlne-Skln........................... 4-1)1 mothy I amlnoazobenzene ................... Fibrous gl:i:s .................................................. C Formaldehyde.................................................. Iron pentjrarbonyl......................................... gr Men ury (Alkyl compounds) -Skin .... M thy I chloride................................................ Methyl 2-ryanoacrylate................................ Melhylcylopentadienyl manganese tricarbonyl (as Mn).................................. Methyl deineton-Skln.................................... Methyl parathion-Skin.................................. Phenollilazlne-Skin......................................... Rosin Core Solder, pyrolysisproducts 1 2 __ 2 -1 g) - - ' 2 0.01 -JOO 2 0.1 - --- Styrene................................................................ CSubllltslns (Proteolyticenzymes)........... 100 -- Vanadium (V205 hime) as V Vinyl acetate................................................. Vinyl chloride.............................................. * Wood dust (non allergenic) 10 200 mg/M* A1 2i> 16 ID 5 5 A D 3 0.06 0.01 210 a 0.2 0.5 0.2 5 0. 1 (as alde hyde) 420 0.0003 (as I00`t pure crystal line enxjrcns) 0.05 30 710 5 ! iterUfliLf0TM5 excePt alk>1)- -0-05 "'^m3 Capital letter* refer to Appendices l) < 6-7 m Diameter. No TLV for coars* flbroua glaa* baa 7el been aet. vi i i. NOTICE OF INTENDED CHANGES (Corn'd) MINERAL OUSTS ivfiaanu ILY + Asbenlot (All type*) Coal duet (bituminous) CrUtobkllte 'Inert* or Nuisance Particuletee Quarts . Silica, (used Trtdymtu 5 flbere/ml > 5m In length*) 2 mg/m3 (respirable duel)*01)2 Use one-hall (he value calculated from the count or mass formulae for quarts, 10 mg/M3 or 90 mppcf (whichever Is the smaller) of total duet < 1% 6102") TLV In mppcf; 900 %SlOa*10 TLV for respirable duet in mg/m* 10 mg/M3p^ __ % Respirable quarts 2 TLV for "total dust", respirable and nonresplrablet 30 mg/M3 % quarts 3 Use quarts formulae Use one-half the value calculated from formulae for quarts. * 1910 Revision or Addition k) As determined by the membrane filter method el 430 X magnification phase conlreet Illumination. Concentration# > 5 (Ibera/ml, but not to exceed 10, may be permitted for 19-mlnute periods each hour up 10 five time* daily. ml "Respirable" duet at defined by the British Medical Research Council Criteria (I) and aa sampled by a device producing equivalent reeulte (2), (1) Hatch, T.C. and Cross, P., Pulmonary Deposition and Rententlon of inhaled Aerosols, p. 149. Academic Press, New York, New York, 1994. (2) Interim Guide for Respirable Mase Sampling, AlHA Aerosol Techno* logy Committee, AOU J. 31, 2, 1910, P- 1*3. i) Thla automatically reduces all parUculats substances in Adopted Usl with TLV of 16 mg/M* to 10 mg/M*. p) Both concentration and per cent quarts for Uit application of thla limit are to be determined from the fraction passing t siss-eelector with Uw following char acteristics: Aerodynamic Diameter (i| (unit density sphere) 1| l.ft t.l 4.0 10 % peering eelector 90 14 40 14 0 > 33 O APPENDIX A Al Because of the high incidence of cancer, either In man or in animals, no exposure or contact by any route, respiratory, oral or skin should be permitted for the compounds: 2-Acetylaminofluorene 4-Amlnodiphenyl Benzidine & its salts Dichlorobenzidine 4-Dimethylaminoazobenzene beta-Naphthylamine 4-Nitrodiphenyl N-Nitroaodimethylamine beta-Propiolactone Because of the extremely high incidence of bladder tumors in workers handling beta-naphthylamine and the potential carcinogenic activity of the other compounds, the State of Pennsylvania prohibits the manufacture, use and other activities that involve human exposure without express approval by the Department of Health. A2 Polytetrafluoroethylene* decomposition products. Thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products containing carbon, fluorine and oxygen. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recom mended pending determination of the toxicity of the products, but air concentrations should be minimal. A3 Gasoline and/or Petroleum Distillates. The composi tion of these materials varies greatly and thus a single TLV for all types of these materials Is no longer applicable. In general, the aromatic hydrocarbon con tent will determine what TLV applies. Consequently the content of benzene, other aromatics and additives should be determined to arrive at the appropriate TLV (Elkins, et al. A.I.H.A.J. 24, 96, 1963). * Trade Namaa: AlgolIon, Fluoti, Halun, Teflon, Tetran APPENDIX B B.l THRESHOLD LIMIT VALUES FOR MIXTURES When two or more hazardous substances are present, their combined effect, ratiier than that of either individually, should be given primary consideration. In the absence of -vj ix. U) information to the contrary, the effects of the different hazards should be considered as additive. That is, If the sum of the following fractions, Cl C2 c,, Tl T2 Tn exceeds unity, then the threshold limit of the mixture should be considered as being exceeded. Ci indicates the observed atmospheric concentration, and Tj the corresponding thres hold limit, (See Example lA.a.). Exceptions to the above rule may be made when there is good reason to believe that the chief effects of the different harmful substances are not in fact additive, but independent as when purely local effects on different organs of the body are produced by the various components of the mixture. In such cases the threshold limit ordinarily is exceeded only when at least one member of the serles/^1 C2 etc.i *1 itself has a value exceeding unity, (See Example lA.b.). Antagonistic action or potentiation may occur with some combinations of atmospheric contaminants. Such cases at present must be determined individually. Potentiating or antagonistic agents are not necessarily harmful by them selves. Potentiating effects of exposure to such agents by routes other than that of inhalation is also possible, e.g. Imbibed alcohol and Inhaled narcotic (trichloroethylene). Potentiation is characteristically exhibited at high con centrations, less probably at low. When a given operation or process characteristically emits a number of harmful dusts, fumes, vapors or gases, it will frequently be only feasible to attempt to evaluate the hazard by measurement of a single substance. In such cases, the threshold limit used for this substance should be reduced by a suitable factor, the magnitude of which will depend on the number, toxicity and relative quantity of the other contaminants ordinarily present. Examples of processes which are typically associated with two or more harmful atmospheric contaminants are welding, automobile repair, blasting, painting, lacquering, certain foundry operations, diesel exhausts, etc., (Example 2.) THRESHOLD LIMIT VALUES FOR MIXTURES EXAMPLES 1A. General case, where air Is analyzed for each component A, Additive effects, (note: It Is essential that the atmosphere be analyzed both qualitatively and quantitatively for each component present, In order to evaluate compliance or noncompllance with this calculated TLV.) Cl C2 . C3 TT TI" TT *i Example No. 1: Air contains S ppm of carbon tetrachloride (TLV 10 ppm) 20 ppm of ethylene dlchlorlde (TLV = 50 ppm) and 10 ppm of ethylene dlbromlde (TLV 25 ppm) Atmospheric concentration of mixture 5 20 + 10 * 35 ppm of mixture 5 20 10 25 + 20 + 20 , ,, 10 +50+ 25 ' 50 ' Threshold Limit is exceeded. Furthermore, the TLV of this mixture may be calculated by reducing the total fraction to 1,0; l.e, TLV of mixture 27 ppm Example No, 2: Air contains 200 ppm of hexane (TLV 500 ppm) 100 ppm of methylene chloride (TLV * 500 ppm) and 20 ppm of per chlorethylene (TLV 100 ppm) Atmospheric concentration of mixture 200 100 + 20 320 ppm of mixture 200 100 20 200 + 100 100 100 . . m * m * m m -0-8*----------------- ms------------------ Threshold Limit Is n$ exceeded. The TLV of this mixture 320 * onr *400 ppm XB. Special case when the source of contaminant is a liquid mixture and the atmospheric composition is assumed to be similar to that of the original material; e.g. on a time weighted average exposure basis, all of Uie liquid (solvent) mixture eventually evaporates. a. Additive effects (approximate solution) 1. The percent composition (by weight) of the liquid mixture is known, the TLVs of the constituents must be listed in mg/M^. (NOTE: In order to evaluate compliance with this TLV, field sampling instruments should be calibrated, in the laboratory, for response to this specific quantitative and qualitative air-vapor mixture, and also to fractional con centrations o( this mixture, e.g.. l/2 the TLV; 1/10 the TLV; 2 X the TLV; 10 X the TLV; etc.) TLV of mixture = la ----------------------------.----- lb Jc_ In TLVa + TLVb + TLVc *......... TLVn Example No. 1: Liquid solvent contains (by weight) 50% heptane (TLV = 2000 mg/M^) 30% methylene chloride (TLV = 1740 mg/M^) 20% per chlorethylene (TLV = 670 mg/M^) TLV of mixture jfT5"0""0 " . 00025+. 00017+. 0003 2000*174(J+670 1 = 1390 mg/M3 .00072 Of this mixture: 50% or 695 mg/M^ is heptane, 30% or 417 mg/M^ is methylene chloride and . 20% or 276 mg/M^ is perchlorethylene These values can be converted to ppm as follows: heptane: 2000 nig/M^ = 500 ppm 1 mg/M^ = 0.25 ppm 695 nig/M^ = 174 ppm methylene chloride: 1740 mg/M^ = 500 ppm 1 mg/M;j = 0. 267 ppm 417 mg/M* = 119 ppm perchlorethylene: 670 nig/M^ = 100 ppm 1 mg/M^ = 0.15 ppm 276 mg/M^ = 42 ppm The TLV of tliis mixture = 174 + 110 + 42 335 ppm. lB.b. General Exact Solution for Mixtures of N Components With Additive Effects and Different Vapor Pressures, (1) C2 Ti + T2 +.......... Cn . Tn = * (2) Ci + Cz +.......... + Cn = T; (2.1) CL C2 T + ~T + fn T 1. By the Law of Partial Pressures, (3) Ci = apt, and by Raoult's Law, H) Pi = FiPi- Combine (3) and (4) to obtain (5) C! = aF,pi. Combining (1), (2, 1) and (5), we obtain (6) f + ^2P2 + FlPl F2P2 "TT" + "Ta-- + and solving for T, (6.1) FlPiQ * F2p2 *......... F,Pi0 F2p2 Ti + T2 *........ * FnPn FnpnO + Tn or |=. n Fjpj <8.2) _ i = 1 T" l 1-1 F'lPl0 TT ARD 002716 x. T - Threshold Limit Value in ppm. C = Vapor concentration in ppm. p = Vapor pressure of component In solution. p = Vapor pressure of pure component. F = Mol fraction of component In solution, a - A constant of proportionality. Subscripts 1, 2, . . . n relate the above quantities to components 1, 2f . . . n, respectively. Subscript i refers to an arbitrary component from 1 to n< Absence of subscript relates the quantity to the mix ture. lB.c. Solution to be applied when there is a reservoir of the solvent mixture whose composition does not change appreciably by evaporation. Exact Arithmetic Solution of Specific Mixture Mol. Density TLV pat wt. 25C Mol fraction in half-andhalf solution by volume Trichloro ethylene (1) 131.4 1.46g/ml 100 73mm Hg 0.527 Methylchloroform (2) 133.42 1.33g/ml 350 125mm Hg 0.473 FlPl = (0.527) (73) = 38.2 _o F2P2 (0.473) (125) * 59.2 TLV .38. 2 59.2 _ (97.4) (350) = i9L4)_43501 177 30.2 59JS " 133.0 + 59.2 193.0 " l"0(T + 350 TLV > 177 ppm (Note difference in TLV when account is taken of vapor pressure and mol fraction in comparison with above sample where such account is not taken.) 2. A mixture of one part of (1) parathion (TLV, 0.1) and two parts of (2) EPN (TLV, 0.5). C1 _2_ , Cm 0.1 0.5 Tra C2 2Cl Ci_ 2C\ 3Ci 0.1 + 0.5 = Tm 7C] iCj_ 0-5 ' ~T~~ Tn> = = 0.21 mg/MO 1C. TLV for Mixtures of Mineral Dusts. For mixtures of biologically active mineral dusts the general formula for mixtures may be used. For a mixture containing 60% talc and 20% quartz, the TLV for 100% of the mixture is given by: TLV =--------- ---------- =B.4 mppcf 0.8 0.2_ 20 + 2.5 Essentially the same result will be obtained if the limit of the more (most) toxic component is used provided the effects are additive. In the above example the limit for 20% quartz is 10 mppcf. For another mixture of 25% quartz, 25% amorphous silica and 50% talc: TLV = -----------------------------------= 7.3 mppcf 0.25 0.25 0.5 2.5 20 20 The limit for 25% quartz approximates 6 mppcf. APPENDIX C PERMISSIBLE EXCURSIONS FOR TIME-WEIGHTED AVERAGE (TWAI LIMITS The Excursion TLV Factor in the Table automatically de fines the magnitude of the permissible excursion above the limit for those substances not given a "C" designation; i.e., the TWA hnuts. Examples in the Table show that nitroben zene, the TLV for which is 1 ppm, should never be allowed to exceed 3 ppm. Similarly, carbon tetrachloride, TLV 10 ppm, should never be allowed to exceed 20 ppm. By contrast, those substances with a "C" designation are not subject to the excursion factor and must be kept below the TLV. These limiting excursions are to be considered to provide a 'rule-of-thumb' guidance for listed substances generally, and may not provide the most appropriate excursion for a particular substance. Efforts are being made to develop such specific excursions, when indicated to be significantly dif ferent from that recommended by the present excursion fac tors. Substance TLV Excursion Factor Max. Cone. Permitted for short time Nitrobenzene Carbon tetrachloride Carbon monoxide Acetone Boron trifluoride Butylamine Styrene monomer 1 ppm 10 ppm 50 ppm 1000 ppm C 1 ppm C 5 ppm C 100 ppm 3 2 1.5 1.25 - 3 ppm 20 ppm 75 ppm 1250 ppm 1 ppm 5 ppm 100 ppm For all substances: TLV =0-1 (ppm or mg/m^), Excursion Factor TLV = 1-10 "" TLV = 10 - 100 ' "" TLV = 100 - 1000 " M" =3 =2 =1.5 = 1.25 BASIS FOH ASSIGNING LIMITING "C" VALUES By definition in the Preface, a listed value bearing a "C" designation refers to a 'ceiling* value that should not be exceeded; all values should fluctuate below the listed value. This, in effect, makes the "C" designation a maximal allow able concentration (MAC). In general, the bases for assign- ARD 002717 xi. lug or not assigning a "C" value rest on whether excursions of concentration above a proposed limit for periods up to 15 minutes may result in a) intolerable irritation, b) chronic, or irreversible tissue change, or c) narcosis of sufficient degree to increase accident proneness, impair self-rescue or materially reduce work efficiency. APPENDIX D Some "Inert" or Nultmce Particulates **1 Alundum (AI2O3) Calcium carbonate Cellulose (paper fiber) Portland Cement Corundum (AI2O3) Emery Glycerine Mist Graplute (synthetic) Gypsum Vegetable oil mists (except castor, cashew nut, or similar irritant oils) Kaolin Limestone Magnesite Marble Pentaerythritol Plaster of Paris Rouge Silicon Carbide Starch Sucrose Tin Oxide Titanium Dioxide q) When toxic impurities are not present, e. g. quartz <1%. APPENDIX E Some Simple Asphyxiants - "Inert" Gases and Vapors Acetylene Argon Ethane Ethylene Helium Hydrogen Methane Neon Nitrogen ' Nitrous Oxide Propane 1970 TLV COMMITTEE MEMBERS Paul E. Caplan Hervey B. Elkins, Ph. D. W. G, Fredrick, Sc. D. Bernard Grabois, P. E. Paul Gross, M. D. Wayland J. Hayes, Jr., M. D. John W. Knauber Harold N. MacFarland, Ph. D. Frederick T. McDermott E. Mastromatteo, M, D. Col. Walter W. Melvin, Jr.,M.D. Ralph G. Smith, Ph. D. Mitchell R. Zavon, M. D. Herbert E. Stokinger, Ph. D., Chairman William D. Wagner, Recording Sec'y Copyright 1970, by American Conference of Governmental Industrial Hygienists. The American Conference of Governmental Industrial Hygienists will welcome requests for permission to re publish or reprint these Threshold Limit Values. Requests for such permission should be directed to the SecretaryTreasurer, 1014 Broadway, Cincinnati, Ohio 45202. Price Each 1 -- 49 Copies ........................................................ 50 -- 999 Copies ................................................... 1000 - 4999 Copies ............................................. 5000 or more Copies ........................................... 50$ 40? 30? 15? Documentation of Threshold Limit Values. A separate companion piece to the TLVs is issued by ACGB1 under this title. This publication gives the pertinent scientific information and data with reference to literature sources that were used to base each limit. Each documentation also contains a statement defining the type of response against which the limit is safeguarding the worker. For a better understanding of the TLVs it is essential that the Documentation be consulted when the TLVs are being used. Information concerning the availability of copies of the Documentation of Threshold ^imit Values should be directed to the Secretary-Treasurer. ARD 002718 XII. Table 2.2 (continued) Radioactivity: For permissible concentrations of radioisotopes in air, see "Maximum Permissible Amounts of Radioisotopes in the Human Dody and Maximum Permissible Concentrations in Air and Water," Handbook 52, U. S. Department of Commerce, National Bureau of Standards, March, 1953. In addition, see "Permissible Dose from External Sources of Ionizing Radiation,'' Handbook 59, U. S. Department of Commerce, National Bureau of Standards, Sept. 24, 1954. D. S. Department of Commerce Handbook 52 has been superseded by Handbook 69, "Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure," subsequent to the presentation of this report. Handbook 59, TJ. S. Department of Commerce, has been revised by addition of addendum, April 15, 1958. Milligrams of dust, fume, or mist per cubic meter of air. Mineral Dusts SUBSTANCE Aluminum oxide Asbestos Dust (nuisance, no free silica) Mica (below 5% free silica) Portland cement Talc MPPCFH 50 5 50 20 50 20 SUBSTANCE Silica high (above 50% free SiOo) medium (5 to 50% free Si02) low (below 5% free SiC^) Silicon carbide Soapstone (below 5% free S1O2) || Millions of particles per cubic foot of air. MPPCF 5 20 50 50 20 TENTATIVE VALUES SUBSTANCE PPM || Allyl glycidyl ether (AGE) 10 Boron trifluoride 1 n-Butyl glycidyl ether (BGE) 50 Butyl mercaptan 10 Chlorine dioxide 0.1 Chloroacet aldehyde 1 Chlorobromomethane 400 Diglycidyl ether (DGE) 10 Dimethyl formamide 20 1,1-Dimethyl hydrazine 0.5 Dipropylene-glycol methyl- ether 100 Approx. Mg. per Cu. M. 45 3 270 35 0.3 3 2,100 55 60 1 600 SUBSTANCE PPM 11 Ethyl mercaptan 250 Furfuryl alcohol 50 Glycidol 50 sec-Hexyl acetate 100 Isopropyl glycidyl ether (IGE) 50 Lithium hydride Methyl mercaptan 50 Perchloromethyl mercaptan 0.1 Phenyl glycidyl ether (PGE) 50 Phosphoric acid n-Propyl nitrate 25 1,2,3-Trichloropropane 50 Approx. Mg. per Cu. M. 640 200 150 590 240 , 25 Mg/nm 100 0.8 310 1 no 300 2-10 ARD 002719 SUBSTANCE PPM|| Triorthocresyl phosphate Yttrium & inorganic compounds Table 2.2 (continued) Approx. Mg. per Cu. M. SUBSTANCE 0.1 Teflon decomposition products 5 Pentaborane (B5H9) PPM!! * * Approx. Ms. per Cu. M. * * j|Parts of vapor or gas per million parts of air by volume. 'Approximate milligrams per cubic meter of air. *Until more data are forthcoming, it is important that atmospheric concentrations of these materials to which workers are exposed must be kept as near 0 as possible. WILLIAM L. BALL H. E. STOKINGER HERVEY B. ELKINS W. H. REINHART W. CLARK COOPER KEITH H. JACOBSON ALLAN L. COLEMAN, Chairman ARD 002720 2-11 Table 2.3 CHEMICALS CAUSING CHRONIC TOXICITY For exposures of less than eight hours duration the eighthour weighted average exposure should not exceed the Threshold Limit Value (refer to text, "Short Duration Ex posures"). Brief exposures should not exceed eight times the Threshold Limit Value. Aldrin (HHDN) - also skin absorption Aniline - also skin absorption Antimony Antu (Alphanapthylthiourea) Arsenic Benzene Beryllium Butyl Cellosolve - also skin absorption Calcium arsenate Carbon disulfide Carbon tetrachloride Cellosolve Cellosolve acetate Chlordane - also skin absorption Chlorinated camphene - also skin absorption Chlorinated diphenyl oxide Chlorodiphenyl Chloroform Chloroprene - also skin absorption Crag (Butoxy polypropylene glycol) - also skin absorption Cresol 2, 4-D (2, 4-Dichlorophenoxy acetic acid) DDT (Dichlorodiphenyl trichloroethane) also skin absorption O-Dichlorobenzene 1, 1-Dichloroethane Dieldrin, skin absorption Difluorodibromomethane Dimethylaniline - also skin absorption Dinitrobenzene - also skin absorption Dinitrotoluene - also skin absorption Dioxane Dipropylene Glycol Methyl Ether Ethylene Dibromide Ethylene Dichloride Fluoride Dust Hydrogen Fluoride Lead Lead arsenate Lindane (Gamma-Benzene Hexachloride) also skin absorption Manganese Mercury Mercury Organic - also skin absorption Methoxychlor (methoxy DDT) Methylal (formal) Methyl Bromide 2-12 ARD 002721 Table 2.3 (continued) Methyl Cellosolve Methyl Cellosolve Acetate Methyl Chloride Methylene Chloride Molybdenum Monomethylaniline - also skin absorption Nicotine - also skin absorption P-Nitroaniline - also skin absorption Nitrobenzene - also skin absorption Nitrotoluene - also skin absorption Paradichlorobenzene Pentachloronaphthalene Phenol - also skin absorption Phenylhydrazine - also skin absorption Prosphine Phosphorus (yellow) Picric acid - also skin absorption Propylene dichloride Pyridine Selenium compounds Tellurium P-Tertiarybutyltoluene Tetrabromoethane (acetylenetetrabromide) Tetrachloroethane Tetryl - also skin absorption Thallium Thiran (tetramethylthiuram disulfide) O-Toluidine - also skin absorption Trichloronaphthalene Trinitrotoluene - also skin absorption Triorthocresyl phosphate - also skin absorption Uranium Warfarin (3-((alpha-acetonylbenzyl))-4-hydroxy coumarin) Yttrium and inorganic compounds Xylidine - also skin absorption ARD 002722 2-13 Table 2.4 CHEMICALS CAUSING ACUTE TOXICITY For exposures of less than eight hours'duration the eight-hour weighted average exposure should not exceed the Threshold Limit Value (refer to text, "Short Duration Exposures"). Brief exposures should not exceed eight times the Threshold Limit Value. Acrylonitrile - also skin absorption Arsine Barium Cadmium oxide Carbon monoxide Cyanide Decaborane Dimethylsuifate - also skin absorption Dinitroorthocresol - also skin absorption EPN (Ethyl paranitro phenylthionubenzene phosphonate) Ethylene chlorohydrin - also skin absorption Ethyleneimine - also skin absorption Ethyl silicate Fluoroacetates HETP Hydrogen cyanide Hydrogen selenide Malathon (0, O-Dimethyldithiophosphate of diethyl mercapto succinate) Nitroethane Nitroglycerine - also skin absorption Nitromethane 2-Nitroporpane Parathion (0, 0-Diethyl paranitrophenylthiophosphate) - also skin absorption Pentaborane Pentachlorophenol - also skin absorption Propyleneimine - also skin absorption Stibine Strychnine TEDP (tetraethyldithionopyrophosphate) TEPP (tetraethylpyrophosphate) Tetranitromethane - also skin absorption 2-14 ARD 002723 Table 2.5 CHEMICALS CAUSING NARCOSIS Brief exposures should not exceed three (3) times the Threshold Limit Value Acetone Amyl Acetate Amyl Alcohol Butadiene Butanone (methyl ethyl ketone) Butyl Acetate Butyl Alcohol Ter-Butyl Alcohol Chlorobenzene Chloro Bromo Methane Cyclohexane Cvclohexanol Cyclohexanone Cyclohexene Cyclopropane Diacetone alcohol 1, 2-Dichloroethylene Diisobutyl ketone Ethyl acetate Ethyl alcohol Ethyl benzene Ethyl chloride E thy 1 ether Ethyl formate Furfuryl alcohol Gasoline Heptane I lexane Hexanone (methyl butyl ketone) llexone (methyl isobutyl ketone) A-liexyl acetate Mesityl oxide Methyl acetate Methyl alcohol Methyl chloroform Methyl cyclohexane Methyl cyclohexanol Methyl cyclohexanone Methyl formate Methylisobutylcarbinol Methyl styrene Naphtha (petroleum) Naphtha (coal tar) Octane Pentane Pentanone (methylpropylketone) Perchloroethylene Propyl acetate Propyl alcohol (isopropanol) Propyl ether Stoddard solvent Styrene monomer Tetrahydrofuran Toluene Trichlorethylene Trichloropropane Tri fluoromonobromome thane Turpentine Vinyl chloride Vinyl toluene Xylene 2-15 ARD 002724 Table 2.6 CHEMICALS CAUSING IRRITATION Brief exposures should not substantially exceed the Threshold Limit Value \cetaldehyde Acetic acid Acetic acid anhydride .Acrolein Ally! alcohol A1 Ivl chloride Allvl glvcidyl ether Allyl propyl disulfide Ammnge (sodium sulfamate) Ammonia Benzyl chloride Boron trifluoride Bromine Butyl amine n-Butyl glycidyl ether Butyl mercaptan Chlorine Chlorine dioxide Chlorine trifluoride Cliloroacetyl aldehyde 1-Chloro-l-nitro propane Chloropicrin Chromates Chromic acid Diborane Dichloroethyl ether - also skin absorption 1, 1-Dichloro-l-nitroethane Diethylamine Diglycidyl ether Dimethyl formamide 1, 1-Dimethyl hydrazine Epichlorhvdrin Ethyl acrylate Ethyla.mine Ethyl bromide Ethyl mercaptan Ethylene oxide Ethyl mercaptan Ferbam (ferric dimethyldithio carbamate) Ferro vanadium dust Fluoride dust Fluorine Formaldehyde F urfural Glvcidol Hydrazine Hydrogen bromide Hydrogen chloride Hydrogen fluoride Hydrogen peroxide Hydrogen selenide Hydrogen sulfide Hydroquinone Iodine Isophorone Isopropylglycidyl ether Isopropvlamine Lithium hydride Methyl acetylene Methyl acrylate Methyl mercaptan Nickel carbonyl Nitric acid Nitrogen dioxide Ozone Pentaborane Perchloromethylmercaptan Phenylglycidyl ether Phosgene Phosphoric acid Phosphorus pentachloride Phosphorus pentasulfide Phosphorus pentasulfide Phosphorus trichloride N-Propyl nitrate Propylene oxide Pyre thrum Quinone Hotenone Sodium hydroxide Sulfur dioxide Sulfuric acid Sulfur monochloride Sulfur pentafluoride Triethylamine Turpentine Vanadium Zirconium 2-16 ARD 002725 Table 2.7 CHEMICALS CAUSING ASPHYXIATION Brief exposures should not exceed the Thres hold Limit Value Carbon dioxide I lit lilurodifluoromethane nichluromonofluoromethane Oichlorotetrafluoroe thane FI uorotrichloromethane Sulfur hexafluoride Table 2.8 CHEMICALS CAUSING FUME FEVER Brief exposures should not substantially exceed the Threshold Limit Value Iron oxide fume Magnesium oxide fume Teflon decomposition products Zinc oxide Diisocyanotoluene Ethylenediamine Table 2.9 CHEMICALS CAUSING ALLERGY Brief exposures should not substantially exceed the Threshold Limit Value ' 2-17 ARD 002726 Skin Absorption The third order of importance by which toxic chemicals enter the body is skin absorp tion. As is usual, the body provides means which tend to prevent this tvpe of intoxication. There are two defense mechanisms of the skin that protect the underlying tissue against the entry of foreign material. One is the keratinized epidermis and the other is the covering, or mantle, of waxes and fatty acids secreted by the sebaceous glands. While these lavers are effective barriers against most water soluble irritants, they are subject to attack by strong acids, alkalis and organic solvents. The protective mantle is not continuous but is broken by skin openings of gland ducts and hair follicles. It can be seen then that these openings provide an avenue whereby certain chem icals, especially the water soluble type, can gain entrance. Likewise, any impairment to the health of the skin can lead to increased absorption of toxic materials. Dermatitis There are many ways whereby chemicals act to alter or remove components in the dermal protective mechanism. These chemicals have been classified according to their action on the skin by Schwartz, Tulipan and Birmingham. (2) 1. Keratin Solvents, such as alkalis and soaps. 2. Fat Solvents, such as turpentine, petroleum distillates, and volatile hydrocarbon solvents and detergents. 3. Desiccators or Hygroscopic Agents, which tcke the water out of the skin, such as sulphuric acid, powerful alkalis, and calcium oxide. 4. Protein Precipitants, or denaturants such as heavy metal salts, which form albuminates in com bining with the skin. 5. Oxidizers, which by their strong affinity for the hydrogen in water will liberate oxygen. Examples are chlorine gas, peroxide of hydrogen, chromic acid and its salts. 6. Hydrolizers. - Some substances tend to hydrolize when coming in contact with the moisture of the skin, and thus form irritating compounds. An example of this class is hexamethylenetetramine, which on hydrolizing first forms formaldehyde and later goes on to formic acid. 't 7. Keratogenic Agents. - Certain substances act as stimulants to the keratin-forming cells of the skin and are apt to cause acne-like lesions and new growths. Petroleum, coal tar, solid chlorinated hydrocarbons, and their products, are examples of this class. 8. Sensitizers. There is still another group, to which the skin becomes sensitive after exposure for varying lengths of time. These substtnces may be called anaphylactoid in their action. The nitro and nitroso compounds and certain plants and fungi belong to this class. 9. Photosensitizers. - Certain chemicals and plants have a photosensitizing effect on the skin. Worker* exposed to coal tar, petroleum, and many of their derivatives are exceedingly susceptible to dermatitis Solaris and develop marked melanosis. Photosensitivity has been reported from many plants and also for some dyes, expecially the fluorescent dyes. 2-18 ARD 002727 Causes of Dermatitis There are many predisposing causes of dermatitis. Among the foremost are the race, ace, sex and type of skin of the individual, aiso season of the year, preexisting skin diseases and cleanliness. Of all these, cleanliness is bv far the most important single factor in preventing der matitis. Skin cleanliness goes beyond the mere periodic washing of the hands. It includes the over all skin consideration, i.e., daily bathing, wearing clean work clothing, and using protective clothinr:. In fact, most dermatitis results from a combination of soiled clothing which provides a prolonged close skin contact with the dermatitis producing agent and a failure to thoroughly clean the skin at appropriate intervals. The cleansing agent itself may require special attention since many solvent cleaners and even harsh soaps are frequently responsible for dermatitis. Some, of the more impor tant chemicals that cause dermatitis either by direct contact or by sensitization have been listed by Schwartz, Tulipan and Birmingham (2) and are shown in Tables 2.10 and 2.11. Table 2.10 PRINCIPAL PRIMARY IRRITANTS INORGANIC: 1. Acids (including some of their salts) Arsenious Chloroplatinic Chlorosulfonic Chromic Hydriodic Hydrobromic Hydrochloric Hydrofluoric Hydrofluosilic Nitric Perchloric Phosphoric Sulphuric 2. Alkalis Alkaline sulphides Sodium hydrate, carbonate, silicate and metasilicate Potassium hydrate and carbonate Ammonium hydrate and carbonate Barium hydrate and carbonate Calcium oxide, hydrate, carbonate and cyanamide Trisodium phosphate 3. Irritant Elements and Salts Antimony and salts Arsenic and salts Chromium and alkaline chromates Copper sulfate, copper cyanide Mercuric salts Silver nitrate Zinc chloride Elements sodium, potassium and phosphorus burn the skin 2-19 ARD 002728 Table 2.10 (continued) ORGANIC: 1. Organic Acids and Anhydrides Acetic, anhydride, chloracetic (mono, di, tri) Amino naphtliol sulfonic acids (F.H.J. Koch's, Laurent's) Anisic Carbolic Maleic Cresylic Metanilic Formic Oxalic Lactic Salicylic 2. Organic Alkalis Lthanolamines Methylamines 3. Organic Solvents Petroleum solvents Coal tar solvents Chlorinated hydrocarbon solvents Esters Ketones Turpentine Terpenes Carbon bisulfide Alcohols 4. Essential Oils 5. Acne Producers Petroleum oils Cutting oils Pitch Tar Paraffin (impure) Solid chloronaphthalenes Solid chlorobenzols Solid chlorodiphenyls Chlordiphenyloxides Solid chlorophenols 2-20 ARD 002729 Table 2.11 SENSITIZERS 1. Ove Intermediates Aniline and compounds Chlor compounds Nitro compounds Acridine and compounds Naphthalene and compounds Benzidine and compounds Benzanthrone and compounds Naphthylamines 2. Dves Pur and Hair - Paraphenylendiamine Aniline black Paramido phenol Leather - Chrysoidine Bismark brown Nigrosine Amido-azo-toluene Amido-azo-benzene F abric - Crystal and methyl violet Malachite green Auramine Metanil yellow Brilliant indigo, 4 G Erio black Hydron blue Indanthrene violet, R.l lonamine, A.S. Pyrogene violet brown Orange Y Safranine Sulphanthrene pink Rosaniline 3. Photo Developers Metol Paraphenylendi amine I lydroquinone Para-amido-phenol Pyrogallol Bichromates Paraformaldehyde 4. Rubber Accelerators and Anti-oxidants Hexamethylene tetramine Guanidines Mercapto benzo thiazole Tetramethyl tliiuram monosulphide and disulphide Para toluidine Ortho toluidine Tri-ethyl tri-methyl triamine Phenyl beta naphthylamine Monobenzyl ether of hydroquinone (causes leukoderma) ARD 002730 2-21 Table 2.11 (continued) Son ns Containing excess of free alkali Containing perfumes Containing antiseptics 6. Insecticides Creosote Nicotine Tar Pyrethrum liotenone Thiocyanates Organic Phosphates Mercury compounds ) Phenol compounds ) Petroleum distillates ) Arsenic compounds ) Fluorides ) Lime ) ^|sq p j ' 7. Cosmetics Those containing irritant or photosensitizing dyes, essential oils, perfumes and resins 8. Oils Cutting oils (the inhibitor or antiseptic they contain) Coning oils (cellosolves, eugenols) Sulphonated oils Linseed oil Mustard oil - also P.l. Coconut oil Cashew nut oil - also P.l. Tung oil F.ssential oils of plants and flowers 9. Resins Pine rosin Natural - Wood rosin Burgundy Pitch Alkyd Vinyl Synthetic - Acrylic acid resins Phenol formaldehyde Urea formaldehyde Japanese lacquer Dammar Copal Melamine formaldehyde Sulfonamide formaldehyde Chloro-naphthalenes Chlorobenzols Chlorodiphenyls 10. Coal Tar and Its Direct Derivatives Acridine Anthracene Phenanthrene Carbazole Pyridine Fluorene Naphthalene Phenol - also P.l. Cresol - also P.l. Chlorophenols Cumaron Epoxies Polyesters 2-22 A.RD 002731 Table 2.11 (continued) 11. Explosives Trinitrotoluol (TNT) Trinitromethylnitramine (Tetryl) Fulminate of mercury Hexanitrodiphenyl amine Dinitrophenol Dinitrotoluol 12. Plasticizers Propylene stearate Butyl cellosolve stearate Diamyl naphthalene Dibutyl tin laurate Dioctylphthalate Lead styphnate Ammonium nitrate Sodium nitrate Potassium nitrate Picric acid and picrates Sensol Methyl cellosolve oleate Methyl phthalylethylglycolate Phenylsalicylate Stearic acid Triglycol di (2, ethyl butyrate) Symptoms of Dermatitis The task of diagnosing occupational dermatoses lies within the responsibility of the in dustrial physician and the dermatologist. However, an acquaintance with the general symptoms of the dermatoses is important to the industrial hygienist not only in his responsibility for suggesting preventive measures but also in investigating cases of alleged occupational origin. The symptoms have been well described. (2) These (symptoms) depend in large measure on the cause and the clinical type of the lesion. In cases caused by conentrated irritants or by hypersensitivity, where the onset is sudden, the patient first notices itching of the exposed parts. This is followed by an erythema, papules, vesicles, edema, oozing and crusting. The eruption is an acute moist eczema. The inflammation may be arrested at any of these stages, and if due to a chemical usually improves during the week end while away from work. A worker may not develop symptoms for a period of time varying from a few hours to a few days after contact with the offending substances, and in cer tain cases of hypersensitivity it may take years of contact to become sensitized. It is likely that in such a case an established immunity was broken down. Some workers develop only a mild dermatitis, are able to continue working and finally become immune. In others, the dermatitis is so severe that they have to stop working. Workers who suffer a severe attack do not as often develop an immunity as those who suffer a mild attack. Immunity, if developed, generally lasts only a short time, from a week to a month, after discontinuing work, but in a few cases may last for many years. The worker who, after working without any trouble for many years, suddenly becomes sensitized to materials be formerly handled with impunity and reacts with a severe dermatitis never becomes immune. Some dermatologists say that such a worker may even become hypersensitive to many of the ordinary materials of daily life and as a result suffer from a chronic eczema even when be gives up his occupation. Fortunately, this rarely occurs and the author has not encountered it. 2-23 ARD 002732 In cases of exposure to mold irritants over long periods of time the early symptoms are not annoying, hut consist only of a mild irritation followed bv thickening of the skin and loss of elasticity. This later results in cracks and fissures, and the open sores are irritated and kept inflamed by the entrance of more of the causative agents. L leers result and these heal only with difficulty while the patient is working. Such cases present the picture of a chronic fissured eczema Dehydrating agents such as salt, sugar, and low concentrations oj lime and formaldehyde may cause such lesions. Suck cases are not due to allergy but to an exhaustion of the defense meohanism of the skin. Substances like mineral oil, grease, paraffin, chlorinated synthetic waxes, and coal tar pitch can not only cause dermatitis but if allowed to stay in contact with the skin for long periods will block the pores, irritate the epithelium of the skin glands, and cause comedones, acnes and cysts, which may become infected and result in folliculitis and boils. Petroleum, unrefined paraffin, grease, tar, and pitch cause epithelial proliferation which man result in keratoses, papillomata, and epithelioma of the exposed parts. Tar, pitch, soot and petroleum may also cause scrotal concers. Exposure for long periods to certain aniline derivatives such as alphanaphthylamine, betanaphthylamine, and benzidine may cause pipillomata and carcinomata of the bladder. Arsene produces keratosis of the palms and soles when taken internally but the author has never seen these lesions from occupational exposure to arsenic. Occupational mycotic infections such as ringworm of barbers and myciiscs of the hunds and nails of vegetable and fruit canners are not infrequent, but their appearance does not differ from similar infections of non industrial origin and it is often difficult to prove occupational origin. Parasitic deseases induced by acari form only a small group among occupational skin affections. The symptoms do not vary from those found in non-occupational parasitic deseases in any way and they must be identified as occupational by means of other criteria. Bibliography 1. Smyth, H.F., Jr., "Improved Communication - Hygiene Standard for Daily Inhalation," A1HA Quarterly 17, No. 2, 129-185 (June 1956) 2. Schwartz, L., Tulipan, L. and Birmingham, D.J. Occupational Diseases of the Skin, Lea and Febiger, Philadelphia, Pa., 3rd ed., 1957. 2-24 ARD 002733