Document B8dvx4BMBn6GJxJ4kG8DBaQDE

FILE NAME: Owens Illinois (OWILL) DATE: 1939 DOC#: OWILL111 DOCUMENT DESCRIPTION: Presentation from the 28th NSC - Occupational Disease Control t 726 ( !S(h N ational S a fe ty C ongress If# T Tanning Industry: Srr Leather IiiduM riei T anning Sertion: See Meat_ Packing, Tanning amt leath er Industrie* Section. Taylor, F. J . : Problem* in Marine Safely, 343-345. Taylor, V. II,: Problem* in Starting Oil Field Cas Engines, 537-539. Tea (He Industry: A Rag of Safety Trick* (I-augh- hn>, 683-686, Fitting the Safety Program to the P lant Need* (M cIntosh), 680-683, Textile Section: Minute*. 677-691 <>fftcera, 677 678.^ Thomas, J. I : State of Pennsylvania*!! Aid in Coal Mining Safety, 463-467. TlioniiMon, Or. L. M-: First Aid for Q uarry Worker*, 269-271, Tools: Means of Preventing Picaroon or Wood Hook rnjurirs to Feet or !.*&*, 524-525. Procedure to Re Followed In Inspecting Me chanic** Tool*. 523*524 Safely in the |L e of Kdge Tool* (Ktncli), 704- 707. Training Employees: See Education of Workmen. Trespassing: See Railroad*. u I Mil, A * lT*e and Alnt*r of Circular Saws and Their Relation to Safety, 69R-703. 1Mlrich, \V\ and Heydrn, r.. B : Refinery ConNtrurtion Problem*, 543-546. l \ S Government: See Federal Departments. V Van l>uen, IV.' Transatlantic Flying, 236-238. V*|or*: See (ia*es. Vickery, Com. II. I. : Safety Feature* Provided on American Merchant Vessel*. 378*381. Visual Education: Visual Education a* Applied to Safety (Mill*), l|"M32. Vocational Education: Educational Problems in Manufacturing Plant* (Rust), 533*537. Vnuachen, Hr. If. A.: Man's Usefulness and I.imitation* from a Physical Stand]>oint H is Pro|*er Ilaccnient, 181-186. w Waeache, Rear Admiral K. R.: Safety of Life at Sea. 356*358. Warmer, R, 1L: Merchandising Safety, 199*202. W arner, U P,, Jr.: Effective Safety Work in Heavy Industry, 267-268. I Washing Facilities: To What Extent Are the In-1 dustries Providing Washing Facilities, 143-144.1 Weimer, R. M.: Falls and Their Prevention, 630*] 633. Welch, D. U : Handling of Materials, 627-630. Welding: Does an Exhaust System from Elec*,, trical Welding Affect the Type of Weld!, 142-143. J Eye Protection and Weldfe** .529. Meta! Fumes, 62*64. >* _ _ Qualifications of WeflT " 546-549. Safety in Electric Wc Safety in Gas Wefdim 203-208. Welding and Cutting Session: 203-22j . Wheelnclc, C, W .: Air Conditioning and Its Re lation to Fire Control, 43-49. Whitney, W .: Safety--A Formula for Human and Industrial Progress, 262-264. Safety--the Answer to a Challenge, 412*414. Williams, R .: Wood Stickers, Molders amt Match ers, 707*709. Wilson. J. C.: Safety Chins, 709-713. Wilson, L H .: The Safe Handling of Beverages, 329-330. Wood Hooks: See Tools. Wood Preservatives: Health Hazards in the Woodworking Industry (Sayers). 697-698. Wood Products Industry: Health Hazard* in the Woodworking Industry (Sayers), 694*698, Safety Chips (Wilson), 709-713. Safety in the U*e of Edge Tools (Finch), 704- U v and Abuse of Circular Saws and Their Re lation to Safety (U hl), 698 703. Wood Shatters (Gibson), 703-704. Wood Stickers, Molders and Matcher*. (Wil liam*), 707-709. Wood Product* Section: Minutes. 693-7J3. Officer*. 693-6*14. __ z Zimmer, V. A.: What Training Should a Factory Inspector Receive? 73:74. Zocrb. A. S.: Safety Training of Undergraduate Chemical Student*, 292-294, 296-298. CO A li NATIONAL SAFEIS CONGRESS ATLANTIC CITY OCTOBER 16-20, 1939 NATIONAL SAFETY COUNCIL, INC. Copyright. J*3f, Nation! Safaty Council. Inc. Printarf In U. S. A. I 132 8th National Safety ( onyrcss f ( quality of the negative produced with the proper choice of fmr grained film, makes it poscihle to make enlargements of any desiraItic m zc. By the use of auxiliary lenses, copies can be made of photographs draw ings, manuscripts, or other fiat material. The scope of the miniature camera is almost unlimited for those who desire to collect and prepare material for group presenta tion. Practically anything that can l>c pho tographed can lie readily transformed into a slid e or strip film for projection. One other outstanding advantage of the miniature is the use of 35 mm color film which costs in that si2e an average of $2.50 per roll of 18 exposures including processing, an average of 14 cent; per frame. There are two types of color film now available. ally consisting of a sound unit operating in conjunction with a strip film projector. The projector may or may not be auto matically synchronized to the sound record. In some cases combinations of the fore going are available. The opaque projector usually incorporates a slide unit and the strip film projector may be readily adapted for 2 x 2 inch glass slides. In selecting a projector, the basic govern ing factors are : 1. The material to be presented. Pictures, slides or strip films. 2. The size of the audience or the size of the average room in which it is to be used. 3. Portability. 4. Ventilation of lamp housing and sub ject matter. Both of these color films are available in larger sizes blit the cost is prohibitive for non-commercial use tior arc they so readily adaptable to inexpensive projection. Over the past year or so. 1 have about come to the conclusion that two cameras offer the ideal outfit. The second camera should he of the type having ground glass fnctiMng and adapted to the use of cut film and film pack. Outstanding examples of this type camera are easily procurable. l.et'-s take a look at the projector problem. \s with the camera, the heart of the pro jector ts its optical system. Here again it is necessary to rely upon the integrity and reputation of the manufacturer. Projectors belong in one of four separate classes, depending upon design: 1. The opaque projector--designed to pro ject pictures, pages of hooks, drawings, etc. by reflection. In general these are less ef ficient. watt for watt, than other types of projectors. Hence the illuminating system must he more powerful to offset light loss hv reflection. 2. The standard slide projector for either 3*4 x 4 inch or 2 x 2 inch slides 3. The strip or slide film projector for t5 mm film. 4 The sound-strip film projector Hsu- A combination of items 1 and 2 usually defines the size and type projector neces sary. Tn most cases a combination unit is desirable in the interest of greater flexibil ity. It may also be necessary to procure two lenses of different focal length for the projector particularly if a variety of j room sizes may be encountered. The shorter the distance between the projector and the, screen, the shorter the focal length of the, projection lens. For the average projector,! a variety of projection lenses are usually available. The question of portability is more or less self explanatory and is governed almMj entirely by the local situation. Too much the way of durability and projection power should not be sacrificed to portability. 1 believe that the power of a projector lanf should not be reduced below 200 watts. Speaking of power, tny preference is fas a projector using a projector bulb of fiM 500 to 750 watts. A size larger than tl requires a special power circuit which Mg not be available where needed. Tn projectM using projection bulbs larger than 300 wan some means of forced draft ventilatiM must be included. Otherwise damage toi slides or pictures being projected is ahw4 inevitable. Then too, the bulb itself M) be damaged by excessive heat ADJOURNMENT } Occupational Disease Control THURSDAY MORNING SESSION O c to b e r 19, 1939 The session planned for the discussion of problems in industrial occupational disease control was called to order by A. S. Johnson, Assistant to the Manager, Engineering Department, American Mu tual Liability Insurance Company, Bos ton, Mass., who presided. The problems were presented as a panel discussion, and Chairman Johnson introduced the mem bers of the panel, as follows: Roy S. Bonsib, Chief Safety Inspector, [ Standard Oil Company of New Jersey, ifork City* Srren A. Cook, Division of Industrial me and Engineering Research, i General Accident & Liability Ince Company, Chicago. their health. On the left base is the medi cal side. They arc the group employed to carry out the medical part of industrial management's responsibility. And on the lower right is the third base of this tri angle where we find the engineers or in dustrial hygienists, who have to develop and prepare for the operating group the controls of occupational disease, as far as engineering is concerned with controlling them. Now, there is a strong tie between the medical and the engineering phases through that base line of the triangle. What we hope to do in discussing each topic is to develop that tie, which we will call the balance of opinion between the medical phases developed by the doctors on my left, and the engineering phases de veloped by the engineers on my right. I would like to ask this panel a ques tion. For a great many years occupational hazards have been studied in one indus try or another. Would this panel feel, let us say, sanguine that any industrial enter prise is now ready, by employing proper personnel, by searching out the answers wherever they may be found, to solve an occupational disease problem if they have one. and by the proper solution maintain the safety and health of the employees? Put another way, are we still groping in the dark on some of these hazards by reason of conflict of opinion, conflict of experimental data and theoretical expres sion by folks who find the theoretical haz ard in exposure because it is suggested in the book? Will Dr. E. <L Cranch talk briefly along this line of suggestion? DR. CRANCH: This question is a broad one: Is any industry satisfied that it is in a position to solve an occupational disease on the basis of present informa tion? I would say, absolutely yes, for the majority of occupational disease problems are sufficiently understood to adopt effi cient measures for control. A. G. Cranrh, Industrial Toxicology 133 rtment, Union Carbide Company, York City. Leonard Crcenburg, Executive Dir, Division of Industrial Hygiene, York State Department of Labor, } \M 28th National Safety Congress CHAIRMAN JOHNSON: Frequently l hear it said, "Well, why should I do anything about this until you folks come to terms on whether l ought to have two parts |ier million or two thousand parts per million?0 Let us develop this farther and ask the opinion of Dr. E. C. Mriter, on thr engineering side. arsenic and benzol. The chief reason, it seems to me. why we still continue to have poisonings in industry is because the employer and the worker do not realize the gravity of these hazards and do not take the problem seriously enough to in stitute the necessary and proper means of prevention. I>R. M1TKR: I agree with Or. Cranch that there is enough known to solve these occupational disease hazards, if some employers are not willing to do anything at all until all possible informa tion is available, I would say that they are never going to start. In solving these occupational disease problems, we have a progressive solution. In the same way that the 1940 automobile could not have been built in 1920, just so are we progressing in all the branches of engineering, ventilation, ventilation equip ment, and respiratory protective devices, and so I think adequate information is available. A Basis for Truth CHAIRMAN JO H N SO N : l think we have a balance of opinion there. If you have an occupational disease hazard, there is enough knowledge stored somewhere in the hooks and brains to tackle it or solve it in progressive fashion. Rut we are clut tered up, I think, by a lot of crack-brained notions. I have read any quantity of liter ature in which somebody has ventured the opinion that because such and such ma terials are used, we must have a hazard that is just about ready to kill off the population of the plant. Do we know enough about the hazards and control of benzol, silicosis, arsenic, phosphorus, radium, x-ray, and so forth, to sort out the truth and build upon solid fact an effective safety program? Will Dr. Leonard Greenburg develop that for a couple of minutes? DR, GREENBURG: It seems to me that there is a definite body of evidence which is available on the more important occupational poisons and for the more important occupational diseases, that makes it possible to prevent and control these poisonings and these hazards with a great deal of certainty. That holds for substances such as car bon monoxide and lead and chromium and CHAIRMAN JOHN SON : Now l atn going to switch to the engineering side and ask the same question. Let us visual ize an industrial enterprise that is fearful that has a notion that some exposure is a serious one, and wants to know if there is anything from an industrial engineering standpoint that will make it impossible nr difficult to devise the proper instruments to measure the quantity of exposure, whether it be dust, gas or fume. I am going to turn that over to Warr Cook, MR. COOK: Today we have more methods available for finding out how much of the injurious materials a man if being exposed to than we have ever had in the past. Formerly it was a very labori ous procedure in most cases to analyze the atmosphere inhaled by the worker. Today in connection with more and more of the injurious materials, we are having placed in our hands and are having de* velopcd methods which will quickly tel us how much of the injurious material w in the atmosphere breathed by the worker. We have devices which will determine the concentration of carbon monoxidt' merely by reading a gauge. Similar equip ment is being developed for other injuri ous materials. For vapors, about the but device is the Innerperometer. and we hog we will be able to get equipment of ttria kind manufactured in this country onel these days, Hut at the present time it b . rather difficult to obtain. Tracticalty all of the injurious materidb' in industrial atmospheres can be deH*; mined. Some of the methods are m eti simple than others, but methods are behff; simplified all of the time so the safety gineer in the plant can avail himself el these methods. * CHAIRMAN JOHN SO N : Now I m going to ask Roy Bonsib a rather cririMI question. In cases of doubt, where fttf! has to be balanced with knowledge. wedlj hr think it advisable to attempt to (trig a hazard in a plant without tedmM Occupational Disease Control /1 135 measurement? That is, by visual observa tion. Or does he feel that it is beyond alt question desirable to have the survey made technically by industrial hygienists or by men trained to sample properly with proper instruments ? MR. BONSIB: 1 think the greatest trouble in industry today is that there has been too much guess work. In deal ing with insidious problems such as the new substances and some of the old sub stances which have been introduced, it is pretty hard to hang your hat on every thing, and the average executive today wants to know exactly what is what, and you cannot know that without concrete evidence. You have got to get definite in formation and data. When once you know the facts, which can only be obtained through technical means and by experienced people, you can give them something definite on which they can base definite conclusions and on which you can base your preventive measures. CHAIRMAN JO H N SO N : Now I feel assured that we can discuss some detailed problems. We have our base. W e are in agreement that there is no ordinary occu pational disease hazard that cannot be | aped with, that there is sufficient evi; dente to sort fact from fancy, that there Varc instruments sufficient in quantity and kind for proper engineering analysis, and dat there is no need of guessing. , Let us start now an occupational disauc control program. We have Plant X. ; the management at the top says, "Find ; ^ hazard, if any. Control it, if need be. I am setting up a medical department; I am vetting up engineering occupational bpnistf. I want you fellows to work out : ft fmgram so that my operating dopartan t can install the necessary safeguards, ataarver they may he, and assure me that ; te a will be no emergence of disability by ifse exposures/* BHie Medical Program build first the mediraf half of am. Of what docs it generally . 0. A. Sander? NDER: I am glad you empha- to a particular occupational hazard is as necessary as is the exact determination of a hazard by engineering methods. The appearance or the findings in any group of workers exposed to a particular dust, or what have you, gives an accurate picture of the hazard which has existed over a period of years. That picture is one which the engineers cannot give you, because their dust counts or other deter minations may be only temporary or may vary from day to day. It may have changed considerably in the past few years; the hazard may have been for example, ten times as great two years before as it was on the day the dust counts were made. So no*occupational disease control is ade quate without initial examination of all employees. CHAIRMAN JOHNSON: Or. Sander has developed the need for the medical examination as a survey question to deter mine whether conditions as they have ex isted have produced any pathology in the men. Let us assume that, and install our program of control. Or. Grecnburg, what do von feel about the need for periodicity in the examination program? DR. GRKENRURG: That would largely depend on what particular hazards were present in the plant itself. In certain cases it would be desirable to examine workers very frequently, perhaps even as often as once a month; and in other in stances it might be very satisfactory to examine them once a year* depending on just what particular substances the work ers were exposed to in their daily occupa tion and how satisfactory the technical means of control were. For example, in the case of benzol, it might be satisfactory to examine workers every three months. I believe in the case of tetraethyl lead, the du Pont Company examines its employees about once a month, though I am not quite sure about that. In the case of sand blasters, it might be desirable to examine them and x-ray them every six months; whereas in the case of foundrymen it might be perfectly satisfactory if the men are engaged in ordinary foundry work to examine them once a year and x-ray them once a year or once every year and a half. It would he largely a question of judg ment. depending on the particular occu- ( 130 2Xth National Safety t ongress pation and the particular substances em ployed. CHAIRMAN JOHN SO N : I would like to ask Hr. ilrcriibttrg to amplify just one point If the survey about which Dr. Sander spoke discloses no specific occu pational disease hazard as having caused any pathology--and that is the situation that obtains in most plants--hut still there may be some moderate exposures to this or to that and the management wants to be perfectly sure* how often as a general thing should those men come up for re examination? Understand, this survey has disclosed no pathology, no damage, nothing you can put your teeth in or hang your hat on as indicating a great need for engineering changes in current methods of control. consider carefully the opinion expressed there. You will observe that he has placed the burden upon his own profes sion, by careful discussion, of course, with the management that is to pay the bill; but the decision must rest with the doc tor upon the evidence as presented by the conditions of the plant and the employees themselves. There is no cook book formula which says you must put employees through the mill at standard intervals. But the making of medical examinations is another thing. It always presents problems, because men frequently are frightened when they know they are being examined to see if there is anything the matter with them, not just being examined to see if they are all right. They are always fearful that some dire calamity may overtake Re-examination Periods DR. GREENBURG: That would largely depend on whether there were any hazardous materials being used in the plant. If the condition of the men at the time of the initial examination was quite negative and no hazardous material is be ing used in the plant, I should say the de cision as to whether or not you arc going to have physical examinations is largely them soon. It is a real personnel prob lem, one that has to be handled with judgment. 1 am going to ask Dr. Cranch if, in his long experience of examining a great many employees for operating exposures that might not be hazardous, he has al ways been able to keep those employees calm uiul collected and quiet and quite content with what things were found. an open one, and a matter of wide judg DR. CRANCH: Physical examination ment. programs for occupational disease con I'or example, in the case of a depart ment store's employees, where young women act as salesladies, under ordinary conditions, it might not be necessary or desirable to give them physical examina tions more, than once in five years, per haps not even then. If. on the other hand, the physical ex aminations were quite negative* and vet toxic materia1* are Heine employed, the decision would depend on how toxic those materials are and what the analysis of the plant atmosphere shows. trol can hardly be divorced from a physi cal examination program aimed at general health conservation. Where it is possible to have a medical service, where the physi cian is in daily contact with the man. physical examination presents far fewer difficulties than where it is done only for the sake of occupational disease control If an outside physican com es in to ex. amine certain gTOups of men at intervals nt from one m onth to tw o year*, me logically Have a rig h t to expect that there may be som ething going wrong xridi those who arc called in frequently, 4 It seems to me that the answer to the that leads to considerable nervousness m question is a matter of judgment which their part as to w hat will be found. must be based on a comparison of the relative hazards of the exposure as com pared with the cost and desirability of continuing intensive physical examination, and only by knowing the detailed facts can one arrive at a sound decision in a particular given instance. There is a matter of psychology m! practice in carrying out such a program 4 examinations. It is much simpler. whvN it is possible to arrange it, to have rea ably frequent examinations for gened health conservation, and these examitt tions, then, will be included in the rtfd l CHAIRMAN JOHN SON : 1 think procedure and help to determine ihe fifed that it is very important for you all to of an occupational disease exposure. ) Occupational Disease Control 137 As Dr. Grccnhurg said, we do not at tempt as a rule a routine examination at a fixed interval of a year, we will say. The periodicity of our re-examination is determined largely by several factors: first, the possible exposure to occupational disease hazards; second, what we notice in connection with that man's health as the days go by. Our supervisory force is usually in structed to send in any man who seems a little under the weather, who does not seem to be doing well, who seems to be slipping a little. From their recommenda tions often we pick up cases that certainly require examination which otherwise would easily have been overlooked. Another thing which we have to remem ber is that many symptoms are common not only to occupational disease expo sures incident to life in general; and the medical program for the control of occu pational disease is therefore extremely important in that the contact must be es tablished with the men to determine what changes are going on and what is their origin. CHAIRMAN JOHN SO N : The im portant point to me is that you cannot drag in a physician from the outside who is a total stranger to your problem, merely because he is an expert toxicologist or ex pert something else, and ask him to set up a medical examination or control program for about a week, and then depart. Hire him to consult with your own physician, but let your own physician so fold the occupational disease program in to the general health conservation pro gram, that the findings of the one serve to augment and support the findings of the other. Xow I am going to talk to the engineers, *4 assume that a survey has been made fc which we have discovered a hazard ^Rciently dangerous so that, in the docW%opinion, something ought to be done Amt it. I am not assuming that it has flMtio far as to kill men, but it has manik M itself either in moderate early symp m or some actual demonstrable pak h (y in a few. I wint to ask this group of engineers tifcl they want the medical men to tell Am which they may use to utmost adM p in their own work in connection with surveying to locate and find the hazard that they want to control. W ill Willis Hazard discuss that one? MR. 1IA/CARD: It seems to me th at the most important thing that the doctor can tell the engineer is what his findings are from the physical examination. T hat more or less determines how serious the hazard is; it often isolates it to certain in dividuals in the plant, and that points the way to places that should come under en gineering control in that regard. CHAIRMAN JOHNSON: Perhaps you have already visualized what I am leading to. 1 want Mr. Bonsib to develop thpt a little farther. Here we have the medical examination installed to disclose what is wrong, if anything. I want him to develop the engineering control method. What fact and what data does he need to go aImut his business? Engineering Control MR. BONSIB: Since the amount of damage to the human mechanism depends upon the exposure and the concentration, the engineer should know the maximum allowable concentration to which he would have to maintain the working atmosphere or the working condition, and as an en gineer that is something that the medical profession must give so that the engineer will have something to which to work. 1 think the answer to the question, then, is that it is very essentia! that the thresh old or maximum allowable concentration permissible be known. CHAIRMAN JOHNSON: I do not think we will quarrel about that. I am certain no engineering group will stick out its neck far enough to define for the medical profession what constitutes the safe threshold limit. It is not quite the answer to the question I had in mind, however. For a great many years, you know, the medical profession has been conducting its work successfully in industry, main taining the greatest degree of confidence between the employees and the doctor through the fact that the doctor never revealed what was the matter with the man if there was anything wrong. He grades the men in a general way--employ able, or employable subject to medical 138 2Sth National S a fety Congress nervier, or employable in limited expo much dust. 11 had been shown tha t sures. gypsum dust itself docs not cause silicosis I think ( have Mown o|en a question or injury to the lungs. Where there is here: Can the doctor inform the engineer silica sand, we look for that injury to the of a sufficient number of facts al*out the lungs and the development of fibrosis and hazard to which these men have leen ex silicosis where the exposure is high and posed without weakening that professional continued over a long period of time. confidence which he has established in Consequently, where about half of the the workmen whom he is examining? material used in this operation was silica W hat f want this group of engineers to sand, t was the guess of the engineer that develop is: Can they use adequately mass here was a condition which had to be con information, or information about the trolled effectively to keep the dust concen group, without having to know that Mike tration down to very low levels.* Oarnbrowski is about one month from T o everyone's surprise, the x-ray exami emerging with a disability* Will you de nations of workers who had been exposed velop that. \fr. Hazard? to these operations for a number of years, MK. HAZARD: I t seems to me it is showed that there was no development of entirely possible for the engineer to use fibrosis. the medica! results in a purely statistical Further engineering data was collected, manner. Hr does not have to know who and it was found that two things hap is sick or whether it is Mike Dambrowski pened. In the first place, the grain size' or somebody else. It is extremely impor of the sand was rather uniformly large tant that hr know the number of people and well washed. There was no abrasive who are showing the same ailment and action to produce a great number of fine the number of people who are working in particles. In the air itself, the concentra the department or the plant as a whole. tion of free silica was not SO per cent, or MR. HONS IB: 1 do not see how you ownheatorit twwaos pinerthceenmt.ainFminaatlelyri,all,abbourtatoonrlyy ckannowprwotheactt iatgiasingsotinsgomtoedthoi;nganudnlIesdso ynoout examination showed that where you get see how you can provide necessary pro qguetartgzypdsuusmt fdaullsint gs, eottrlinwgheoruet yoofu thweoualidr teexctteivnet ymoeuashuarvees two igthooount kthneomw.inYg otuo wmhuastt fairly rapidly, the quartz dust settled out know the threshold limit to which the sub mquoarretz raanpdidglyy;psaunmd sethtteledcoomutbienvaetnionmooref sfutamneceoor r dtuhset, misatecraiuasl,inwg htehtehetrroitubilse.gaIsf. rapidly than cither one alone, due to the vou do not know what the toxic limit is, efaracttiothnast wthiethgtyhpesusmilicdaudstuscta, uasnedd aygogulohmad tshicakt iosr. thhoewammouucnht itthetakheusmtoanmmakeechpaenoipsmle large groups of particles which caused this can stand, making due allowance for the more rapid settling. idiosyncrasies of the susceptible. 1 do not Now. the data obtained through the how the engineer can provide the medical examination and the x-ray was ryacr* * hat gave the hint that the cost and the ! **- r a ^ ' a " :va4 tenets the " c t r d ar that opera`vr. -as rsr a ar-*a* a* i* *v:M rormalf 'rtttr* i -<* ****-:--' 7 z'r -- ni* v T**- x:~Tt ~rr*:z*~~ v* \ y v iHiq w o m e th itv - n.*c*t at In oiIict ***' t 'zr<~r~ he must reduce that concentration to the CHAIRMAN JO H N S O N : 1 think point below which it wilt not make any- illustration hinds together these various one sick,and the length of exposure neces points. sary to which that person must be ex I have watched that particular study posed. veloped with a great deal of interest, H * MR. COOK: An instance might be cited where other factors than threshold limits have been utilized. For example, in the gypsum industry, in certain plants for a fact, the engineers did not know.tf did not have to know, anything about tkfl men as individuals; the doctor kept ik l in his files completely. < there is what is known as a sanded plaster Now let us summarize for just a mm manufacturing operation where there is ment. to see where we have arrived. Wfc Occupafiottai disease Control ) 139 have the doctors and the engineers as the two bases of our triangle. Our panel feels sanguine that hazards can be controlled. We know enough, there is enough knowl edge in the aggregate to control them. We say that the need for a medical pro gram is as vital as the need for an en gineering program; that the doctor ought to be the plant doctor, augmented by such specialists as he needs to employ to coun sel with him; that they have a certain amount of factual information that they must turn over to the hygienist or en gineer for his use as a check for his per formances, and that the medical crowd should tell the engineering crowd how low the hazard must he taken to consider it reasonably safe; that the engineers are perfectly willing and able to tackle the hazard in some fashion if they know those things; and the periodicity of the exami nation to find out whether the engineers did a job or not depends upon the condi tions as the doctor finds the record written in the men themselves. Of course, the engineers are going t continue to use the instruments of survey to check their own results. Now 1 am going down to our printed program and explore some of the <juostious suggested there. The panel will dis cuss phases of exhaust systems. Are there in the engineering catalogues, data de scribing machinery of one kind or another to make it possible for the engineer to design an exhaust system if he wants it, or thinks he needs it? Are there enough high grade, glorified vacuum cleaners on the market to pick one out of the catalogue amt install it in the plant, and expect it toproduce results? Dr. Meiter, wilt you develop your thoughts on present market conditions of tottor-made exhaust systems as against fiiKcring design of exhaust systems to ft the individual plant circumstances*? Exhaust Systems Oft. MEITER: In my opinion, there is M available ready-made exhaust ventila t e equipment. The assumption that you elect from a catalogue and ventilate JMr problems has been a great drawback M * progress of this work. I f that 1 mean this: Oftentimes a conM will have, say, a local tin worker. Upp call him in and he, without know ing what the' requirements are of the State Code, without knowing the limits to which the gas, dust or fume has to be exhausted, immediately sets about and de signs a hood. Then, without even knowing how much air can he handled by that hood, he looks into the classified section of the telephone book and calls up the fan company. The fail company has a salesman, but he is not in, so the office girl looks up the technical data, and the company ships the fan. When this ventilating system is finally installed, the sheet metal worker says, "Well, the sheet metal work portion of it is all right, and that is all I guarantee." Then the fan coifipany, on the other hand, says that the fan delivers a certain volume of air at the speed shown in their catalogue, so they wash their hands of it. And finally, when the whole thing is in, it does not work and a job has been poorly done. So the point I wish to make is that ventilation, no matter how simple, requires technical knowledge and technical instru ments to determine when the system is really working. CHAIRMAN JOHNSON: t think Dr. Meiter has put his finger on a very critical point When I speak about engineering control. I mean engineering control, and l do not mean tinsmith control. Let me illustrate. Sander talked about the metal fume fever, zinc shakes. Visualize, if you will, the problem of a shipyard building de stroyers for the United States Navy of galvanized sheet plate, with a great deal of electrical welding work to he done in confined spaces, in the little tanks and cells of which the ship is constructed. There is a plant set up in the field, you might say, lying for nearly a year at its fitting-out basin, a little plant about 325 feet long and 30 feet wide, 25 to 30 feet molded depth and heaven only knows how many tanks in it (they get down to pretty small shies) with welding to be done in most. In those confined spaces welding, steam-fitting and electrical work must be done. Can you imagine a tailor-made ven tilating system being used there? Now let us go to the next question, pro tective creams and lotions. Let us have clearly in mind that a cream or a lotion is smeared f i n the skin for a purpose, and i 4M 2Hth National Saf et y ( on</res.\ uvually the purpose is to prevent the moderate amounts of something or other from coming into contact with the skin. These creams and lotions are of two kinds, those that arc water soluble for use in oily exposures, and those which arc oil soluble for use in aqueous exposures. This use of cream, I declare arbitrarily, as Chairman of this party, is not in lieu of any other control. These creams are used because controls cannot he made absolute, and because there arc sensitive skins to he taken care of. Dr. ( ranch, would you tike to discuss the effectiveness and the use of creams, from the viewpoint of the doctor who has a cock-eyed purchasing agent who buys an oil soluble when lie wants a water soluble, and vice versa? Protective Creams and Lotions means of a patch test or by actual experi ence in the use of the cream. In that case, some other means of protection must be adopted, or the man assigned to other work. 'The great proportion of creams now on the market appear to be reasonably free from any irritants or substances that are particularly likely to bring about an al lergic reaction. The main thing is to select the one designed for the type of protec tion required. These creams, we have found, are often considerably abused. Men seem to think, in many places, that the cream has to he applied in a coating that by its mechanical thickness to the naked eye wilt protect the skin. I have seen a man put on a quarter of a pound where half an inch Mpice'/ed out of a tube would probably have answered the purpose. I>K. C liA K tT I: I think you have In that rase, they often run into other started something. Protective creams cer diHirnltics. Many of these creams which tainly have a field in the protection of protect from oil substances, arc creams skin from various irritant substances. I which have a soap base; the men are simply would put far ahead of the use of protec running around in a soap poultice, and tive creams, however, good personal they work up an irritation which is as hygiene ami thorough cleanliness on the great or in some cases greater than that part of the worker. Where that is ob which would have resulted from the ex tained. the question of protective creams , posure they sought to prevent. is of lesser importance: sometimes negam i* importance. In the oily cream preparations which protect from water soluble substances, There are certain exposures, however, they offer ns very queer mixtures. Lano- whrre no amour.t of personal hvgiene or- line ax a base, l think, is the thing of <-Wa-V-- w ** - to zr'fr'-t from po*- choice for that type of protection, rather M* harm *1* * t Vta^e a vlare t'-jn a petrolatum. It works a little fur w*- t~e tm* clast*-. ther into the -kin. I beH*\r. ard will pro- V*- 1-i--o v *-1 -i* -- ert in a more th ' rough manner than the *tt~ 'a* ?rer>atavor* which you VnTnarv m the conoidration and *ek<- s-mear over the variate ar.d are more i'n oi any cream, o course, is the nature ra-d> rubbed off and fail in their prow- of *>* *r#- H ( '.n an oily sub- Mr kiaiK -*r ijt- a via^*-r -1uM* \iirtbf r thin:; to con-ider U. that tb* ream w hich will fo rm a <oatm g over th<- Iasi word has certainly not been said vkm and resist th e penetration of the o ih naiff'ftal !>roU-me rreamx; they are in the proem of rather rapid development. I belie** ,\nd. on the other hand, if it is a water there are commercially available muq soluhle substance from which we must suitable type* of protective creams, aad have protection, we must have an oily on tbe other band, they can be made ha^r in the protective cream. for a specific purpose very satisfactory The first consideration, then, is that the cream itself shall not contain an irritant. That incidentally opens up the whole field cm tbe advice of your physician. Yon a get a very satisfactory cream that can I produced in bulk for your own use. of allergv. There are many people sen sitive to certain of the common ingredients used in many of these protective coatings. The\ can probably only he discovered by Respiratory Protection CHAIRMAN JO H N S O N : We continue uith the discussion of rtpfc Occupational I disease ( nnfrtt! ) 141 tory protection. In connection with the examination of thousands of foundrymen, Dr. Sander has explored the opera tions which they conduct so that he knows what they alt mean. He of course has found that some of the men arc pro tected by exhaust systems, and some of the men are protected by personal body protection, either filters or the airline type of respiration. I interpret respiratory protection to mean the kind of respiratory protection that yon stick onto the man. Of course, it is at! respiratory protection, but I wonder if Dr. Sander would like to discuss whether or not he has found by the actual examination of men that the satisfactory type of respirator has been found which wilt actually protect the men. DR. SANDFR: Beginning will* sand blasters, undoubtedly the modern air hel met affords almost 100 per cent protection for the prevention of silicosis, provided the helmet is kept in good working condition, and provided the air pressure coming into the helmet is satisfactory. In the observation of about 300 sand blasters in a seven-year period I have yet to see the first one develop silicosis who had worker! only with the modern hel met. Also, I have seen no so-called firststage cases develop a second stage sili cosis during that interval. A first-stage case has been kept at work; he has not hfen shifted. We feel that a sand blaster with a modern helmet is breathing less dust than anyone else in the foundry as a matter of bet. and there is certainly no point in Hting him out onto the floor, removing fit piece of respiratory protection and ting him more dust than he K getting thu and blasting job. A* far as the other foundry operations It concerned, of course it is always adfcabk to exhaust when possible. There It a few occupations that cannot l>e exiNMtd satisfactorily. One of these is M chipping, and where sand chipping MMbe done, it is advisable for the chip|Bto wear the filter respirators. HowMar.tvru there it is advisable to try some 0m method of cleaning the casting if I n h alt that is feasible--for instance. mAStir with high pressure combined Miff and sand, and so forth. *Vkh ordinary stand grinding, there t< no need of respiratory protection, provided an exhaust system is used and is in proper working condition. The exhaust ventilation for swing grinders is a little more difficult, but it has 1>een accomplished. There are very few swing grinders in Wisconsin that arc exhausted, however. It has been our ex perience that swing grinders have not de veloped as much silicosis as was at first believed, and the reason probably is that by the time they get the castings there is no more molding sand on them. It has all l>ecn removed first in the grinding wheels with all the artificial abrasive, so the oniy silica the swing grinder is breathing is generally plant dust- Mnlders and core makers need no spe cial respiratory protection, in my opinion. A molder just could not do the job very well if he were required to wear a respira tor from morning until night. I do not think I would depend on a respirator for the protection of the man with the tuberculous scar. I would rather move hint to some other job, or move his job somewhere else, or localize his job in a separate room and ventilate it. I see no reason why we should worry about a sand blaster today, even with a tuberculous scar. We feel they are not going to develop silicosis, and therefore we think that what little dust there maj be will have no effect on such a tuber culous scar. We have not permitted sand blasters with tuberculous scars to continue working on that job, but I think we should permit them to do so today, knowing that the hazard of sand blasting ts controlled provided, of course, the equipment is kept in working condition. CHAIRMAN JOHNSON: That dis sertation answers beautifully the question if respiratory protection as far as it ap plies to the foundry, and I think direct analogy will carry that opinion over into almost any other exposure that you choose to carry it into, In order to play absolutely fair with everyone in the audience, I am going to start on the questions that have come to me. and there are quite a number. Here is the first question; Assuming that the development of adequate engin- ( 142 J*Sth N ational S a fe ty ( oacross coring and medual departments is essen tial to properly control dust hazards, how can the smaller plants, those having IDO or 200 employees, cope with this prob lem ami determine whether or not they have a hazardous dust condition or any other occupational disease condition? It would he impossible in many eases for these small plants to set up elaborate and expensive control departments. To lead the answer in a definite direc tion, 1 am going to suggest that perhaps the answer lies in the recent development in almost every industrial state, divisions f on opaliitiiaf disease h>gieue. cither in the Department of Labor or the Depart ment *>f Health. I am sure Dr. Leonard (reenburg vumld like to answer that question. The Small Plant Problem DR. GREKNIUJRG: There are two tilings that the smaller plant may do; one is to make nsc of its insurance company to the fullest extent; and the second is to make use of such facilities as the state has at its disposal, either the Department of Labor or the Department of Health. In approximately 30 states in the Union, there are divisions of industrial hygiene in either the Department of Labor or the Department of Health, and in a few cases in both, and they are always prepared and eager to help the smaller plant, particu larly with such problems as this. Many of the insurance companies have developed divisions of hygiene and have experts on their staff who are also pre pared and able to render service along these lines. It seems to me that the big gest problem is to get the small plant management to recognize that the stum bling block is management itself. Once that recognition has been achieved, it is a relatively simple thing to obtain prac tically free service from cither of these two organizations in an effort to really do constructive preventive work. CHAIRMAN JOHNSON; Let me add one thought to that answer. I am familiar with mo*t of those divisions. In none of them is there anybody carrying a big stick to browbeat or to hammer into shape the mall plants that want help. They are already giving help in an advisory fashion. There has been frar, at times, that you c o u ld mu let a state man into the plant without expecting him to change a recom mendation into ait order overnight. 1 have not seen that in this treatment of the occu pational disease problem. I am not telling you that it docs not exist; l say I have not seen k. 1 have here a question for our engineers. Yesterday they were talking about weld ing metal and fume fever, and so forth. Here is the question: Does an exhaust system from electrical welding affect the type of weld? As I view this qtiextkm, it means this: When you weld with an electric welding process using a coated electrode, the flux ing of the coating produces an umbrella or tent over the weld arc itself and thereby excludes the air from the arc and prevents oxidation of the steel which is being cast into the hole being filled up. and prevents oxidation of any of the material or metal that is in the fused state. Now the question is, if you stick a heavy exhaust there and pull away that vapor which provides the protection, do you ruin your weld? Is the control for health at the expense of the weld, or would it be better to forget that and limit the time of the welding? Docs anybody here want to answer that? MR. BONSIB: I think that if you have general ventilation there would be very little danger of destroying that umbrella that Mr. Johnson has mentioned. Of course, it is advisable to remove those fumes as near the source of origin as pos sible, You have to get within eight inches, and not more than that, to really get effi cient results, and being that close you do not require more than 100 or 200 lineal feet per million. I do not think there is enough cooling action to do damage. As a matter of fact some tests wc were interested in making seemed to indicate that there was no dam age done. However, you conic where the damage would he done if you exceed that but I do not think you need to exceed 100 or 20(1 lineal feet per million. If you have general ample ventilation, then you do not have any danger, in my opinion. CHAIRMAN JOHN SON ; That seems to he a logical conclusion. It is certainly an opinion based upon observation of that O rm 1'aiional Pistuisc i'ottfroi ) 143 sort of problem. The ext question is: "Is there enough silica in the average fire brick to affect workers seriously?" In other words, if we explore clay for its refractory property on the one hand, and its plasticity on the other, is there a descending order of silicosis hazard from the fire brick on the one side, down through plastic china clay or paper clay on the other? Mr, Hazard, the questioner wants you to talk about the amount of hazard in the fire clay, and for want of a better defini tion let us leave out the <Canister brick which is a brick the sand of which we know to be pretty close to 100 per cent silica. MR. HAZARD: I think this is really a medical question. But there are certain fire bricks which are very high in silica, and certain others which have practically none or a negligible amount in them. You have a range there from what might be called a dangerous condition, down to one where you are practically sure no danger exists. It seems to me that if you had a fire brick with very high silica content, with the chipping and knocking of the brick layer against the brick, it might stir up considerable dust and might be a silicosis hazard, but I would like to hear the medi cal side on that question. CHAIRMAN JOHNSON: Will either of the doctors discuss the inherent toxicity of the fire clays as they are normally handled in the manufacture of brick? DR. GREEN BURG: It seems to me the Chairman ought to tell us what the percentage of free silica is in the fire clay. He has talked around the question, but he has not told us the crux of the whole problem. CHAIRMAN JOHNSON: The prob lem seems to me to he related to the potion that maybe these mixtures are so mixed that other things beside the silica produce an alleviating or an ameliorat ing effect to prevent what silica there is fromcausing silicosis. Clays do not seem to produce silicosis. It is the dry-pan grinding of all kinds of things that produces enormous quantities of dust some of which contain silica, and 1 cannot remember at this moment just what the amount of silica is in the ordinary run of fire clays; hut I am not giving the medical answer. It is my thought, that the hazard produced in the clay products is not an inherent one, but one thrown in by violent agitation due to dry grinding operations. Let us go on to another interesting ques tion: "To what extent are the industries with which this panel are familiar pro viding washing facilities, and what are the advantages of washing in showers, and so forth, accruing to the employees on the one hand, and the employer on the other, and how is the thing paid for?'* Well, we know that in some states, washing facilities are required by law in certain types of industries, and in others they are put in. I can visualize the need to develop this question in two ways: one for the con trol of a serious occupational disease ex posure such as lead; and the other, the general industrial hygiene, to get folks to wash on the developed fact that by care ful washing a great many of the dermatitis problems solve themselves. Will Dr. Cranch talk about the pro vision of washing facilities? DR, CRANCH: Washing facilities are most desirable things in any plant, large or small. As the Chairman has said, it is the most important factor in the preven tion of occupational dermatitis, to say nothing of general hygiene to the work men. The vicissitudes of trying to establish any adequate washing facilities in in dustry are great. My first experience occurred over forty years ago as a work man. In that plant there was no water available, although tt was a large plant, and unless you sneaked from the job and went Around to a faucet which was used for sprinkling the front lawn, you had no water available. It was not expected that hands should be washed. A man worked at his job, ate his lunch, worked all day and went home so black as a rule you could not tell his race. Later I became much interested in the development of washing facilities. I re member in one very large plant we put in excellent washing facilities, and it was surprising to see how they were abused even to the point where in some cases we had to discontinue service. In other or- t 144 28th National Safvty Congress ganizations, an attem pt on the pari of the management to furnish good washing facilities met with consistent refusal on the part of the workmen to cooperate with them in the use of these things; even where the workmen were given time out at full pay on company time to wash, ihev would not do it. Kortiinatcly, these conditions have rhanged. and the men themselves now ap preciate those facilities where they arc put in. ami they generally demand them where they arc not put in. I think washing facilities are a most im portant feature in the control of occupa tional diseases, and a number of occupa tional conditions aside from dermatitis. There arc a number of occupations where complete showers are furnished and those facilities arc very largely a measure of prevention of occupational disease; and at the beginning of the day's work the men change to working clothes where previously that was not done. Oil Dermatitis CHAIRMAN JO H N SO N : Here is another question: `'Is it not an accepted fact that nil dermatitis is more of a mechanical break down of the skin than it is a toxic prob lem? How would you overcome the de sire of the employees to use abrasive cleansers on the hands?" Cutting oils and other o ils produce dermatitis, and represent three hazards. One produces a plucking of the hair follicles, which is largely a mechanical thing of nibbing oil and dirt, or what have you, into the skin. Then we have what I think the doctors rail heterothema. which is probably a chemical hunt, an irritation of the ski which is another type of dermatitis. Then there is a third one. which p r o d u c e s Mood poisoning or hnils where the oil has been supporting an infective medium bacteria of some sort. (Tan we solve that oil contact problem by handling the washing of men in a satis factory manner through washing facilities, and the discouragement of the use of harsh abrasive soaps, or doesn't it make any difference? May we have a development of that question from Dr. Greenburg? DR. G R EEN B U R G : In dealing with the whole problem of dermatitis due to the use of cutting oil. you are dealing with several different factors which may produce different types of skin lesions. The cure for alt of these, it seems to me, lies in the use of proper protective oint ment before the men start work in the morning, and the washing up at the end of each shift with the proper type of nonirritating soap. The easiest way to get the men to use a mm-irritating soap is to supply one so they will not purcliase an irritating soap themselves. If you leave it to them, they may purchase one which seems to work rapidly, hut which may have irritating properties. On the other hand, if the management supplies it, they can purchase one of suit able quality which in general may he of a more satisfactory type. The whole problem of oil folliculitis and oil dermatitis can be handled and is handled in many plants on a very satis factory basis, by these simple means, and jso far as l can see does not present any insurmountable difficulties whatsoever. The usual defect in the system seems to be that the plant does not pay any atten tion to the problem until many of the men become infected and many of them have skins which arc more or less ruined . by an accumulation of oil and foreign matter in the pores of the skin. At that time, preventive measures are no longer sufficient. It then becomes *necessary really to cleanse the skin thor oughly and repeatedly so as to once again bring it hack to its normal clean condi tion. CHAIRM AN JO H N SO N : Let us go over to the engineering side and talk on the industrialist who manufactures oils to provide himself a meal ticket and lrie9 to prevent just this hazard from causing trouble. MR. HON SIB: 1 agree with much that the doctor has said about getting good oil in the first place. I think that one of the big causes (and 1 have studied this problem a lot for the reason that you hear many stories of in juries due to cutting oils) is that the oil Occupational Disease Control ) 145 is not kept clean. In the cases we have checked the trouble has been due to the use of dirty oil or using oil over and over again that is filled with small particles of metal These cause small injuries to the skin, and that in turn brings about fur ther damage. So if you keep the oil clean. 1do not think you will have much trouble. I think the practice of men spitting in the oil and using the oil over and over again has caused much more damage than the so-called paraffin acne. CHAIRMAN JOHNSON: The next question is this: "Should employees working in departments subject to occu pational disease hazard be acquainted with and informed of these hazards, or kept in ignorance of them?" I)R. SANDER: Undoubtedly, em ployees should be informed of every hazard to which they are exposed, and they should he informed also of the findings on exami nation. Anyone going to his doctor, for any reason whatsoever, wants to know what was found. In the same*way, an em ployee going to a plant doctor wants to know what was found. He is not paying for (he examination, but that makes no difference, he is still a human being who > interested in his own health and his future years of gainful employment. The practice in Wisconsin with physical examinations has been to give employees a duplicate copy of the report which the employer receives. The Wisconsin Indus trial Commission recently published a declaration of principles on physical ex aminations in industry which everyone in terested in this problem should see. In that it is specifically requested that em ployees liegiven a copy of the report which the employer receives. That is not a complete record or report; d i< merely a statement or lisfing of the important defects. I believe that it is as wrong to give employees complete re ports as it is to give them nothing at all. \ worker is not interested in what his Mood pressure reading was yesterday or * today; he is merely interested in know- whether or not it is significantly high, andthat is all he cares about. CHAIRMAN JOHNSON: Is there anybody else on the panel who would like tadheuss the question? MR. BONSIR: I think you can cause wnrr unrest through fear, by failure to tell the man, than in any other way. He may iiqaginc he has something, d>i<l he worries and worries, and finally becomes a victim of what is known as autohypnosis, whatever that is. 1 think by relieving his mind and telling him exactly what is what, you lift that worry from him and you ease his mind, all of which makes a better man of him. CHAIRMAN JOHNSON: Now let us tackle another question: "Processing of a certain cellulose product involves over night soaking in a solution of .5 per cent formaldehyde, and subsequently consider able formaldehyde odor is given off during the drying of which those in the vicinity often complain. How much formalde hyde would represent toxic proportions? And how could the quantity present in the air best be determined ?" I>r. Meiter, would you like to tackle that problem? DR. MEITER: In my own experience, formaldehyde is irritating enough so that you would not require refined technical instruments to make determinations, be cause it is very easily noticeable in low concentrations. I think proper engineer ing methods could be devised for elimi nating the fumes without using technical instruments, because it is necessary to keep the fumes down to very low concentration, otherwise a dermatitis may develop and also sore eyes. CHAIRMAN JOHNSON: Docs the medical side of our panel wish to develop that any farther? 1>R. ('RANCH: I think that question illustrates one of the phases where it is not necessary to have engineering help in order to determine whether or not you have reached a point of safety. Formaldehyde vapors are not likely to 1m* toxic, since in a concentrated form it is so irritating that just for comfort some relief would he demanded, so that we need not be particularly concerned about what concentration is obtained. There are a number of chemicals of that sort, where the immediate effects are so irritating that toxic exposure would usually he avoided in the course of ordi nary good practice in handling the ma terial. CHAIRMAN JOHNSON: Warren Cook avs he has another idea. 146 JSfh Nnttonal Saf et y ( on<jrvss MR- COOK: The literature does con* tain sonic information concerning the devclopment of irritative actions, and we are wondering in Connecticut whether the concentrations which wore listed in the literature and the irritative action was as* soctated with a tolerable amount of irrita tion, or whether it was in the higher de grees of irritation. We ran some analyses on some formal dehyde gas in an operation where formal dehyde was being used in the manufacture of synthetic resin. The method we used was the bubbling of the air of the plant through water, with two bubblings in a series, and tested with Shift's reagent, the regular method for the determination of formaldehyde; and we got results that were in the area of the breathing zone of less than 20 parts per million, which is usually suggested as a satisfactory con centration. At one point we ran it up to 90 or 100 parts per million, and at that point I found I could keep my nose there for thirty sec onds before T decided to back away from it. But I do agree with Dr. Cranch and Dr. Mciter that where the irritation does get excessive, then the irritative gas can be taken as the determining factor even though with most of the materials the irritation is not the safe way to determine whether a gas condition is or is not safe. CHAIRMAN JO H N SO N : Here is another question: "Is sulphur dioxide gas in concentra tions as low as 10 parts per million for pro longed exposure considered hazardous to the health ?*' Going to the medical side, will either Dr. Grcrnburg or Dr Cranch tell us if sulphur dioxide in such low concentration represents a hazard for continuous expo sure? DR. GREKNBURG: I cannot say off hand. It is just about on the borderline, I think. CHAIRMAN JO H N SO N : Now. if an employee upon examination shows a very slight increase of lead content above nor mal after sixteen years of exposure, would you change his occupation? I do not know what a "very slight" amount of lead is. 1 think presumably this means a few stipple cells, or some thing like that. If an employee upon ex amination shows a very slight increase of lead content above normal after sixteen years* exposure, would you change his occupation? DR. G R EEN B U R G : I would want to know where he showed it, and how. CHAIRM AN JO H N SO N : If I may answer the question, it seems logical that if there is lead showing up, it came from somewhere, and having explored that yon can determine the engineering phase of the control, and perhaps he can stay on the job after you have controlled the lead fumes. Mr. Cook, won't you answer the follow ing question? "W hat instruments are there on the market which are reasonable in cost for small shops to purchase which can be used to check atmospheres in metal spray work for zinc, iron and other harm ful fumes? Must several instruments be used where many types of metals are sprayed during a working day?" Metal Spraying Equipment MR. C O O K : On metal spraying, there are several angles. No. 1, a booth, a ven tilated booth should be used where pos sible. Secondly, the man should in most : cases be given a positive pressure air supply. Now, assuming that the particular1 operation is one in which the man may be spraying brass, there are various method! using the ventilated booth. Let us assume for the moment that he is provided with no respiratory protection. If a man is spraying zinc and the booth is providing adequate exhaust so there is not much ol a cloud of zinc and he does not get metal fume fever, it is probable that it is not necessary to make any determination for zinc. If during the course of the day the man is spraying some lead ami some cad mium, I would feel very definitely that it would be well to run an electrical pre cipitator sample, analyze the sample, and obtain the electric precipitation for lead.j and also for cadmium which would be a routine chemical procedure, and the con-! centratton of both of those should be kept below the suggested toxic limit in order 1 to assure that you are on the safe side. a I would feel that it would not be neces sa ry to analyze for zinc under those coa- Ocfuf*atianal Disease Control ) U7 ditions. or for other of the metals unless there is some additional one that is par ticularly toxic. Hut particularly where you do have lead or cadmium, the deter mination should be made for those, and based upon those determinations you can get an idea on the basis of the relative duration of spraying of those particular metals what the exposure is. DR. ME IT E R : I agree with Mr. Cook, and I believe the solution of this problem is first, the use of a properly ventilated booth so as to eliminate the exposure to the other workmen in the vicinity. The second item is the use of a positive pressure airline respirator to protect the operator. 1 think that conducting total izing operations all over the shop and without adequate equipment, especially where such metals as lead are sprayed, are going to produce occupational diseases. 1 believe the proper thing to do is to start right with the proper type of equipment, by providing the booth and protecting the man, and you will then *not need the sampling devices. CHAIRMAN JO H N SO N : Then the specific answer to the question seems to be the lead precipitator as the one gadget that will he most useful, and the sample should he analyzed quantitatively in the chemical laboratory. I want to ask the doctor a question in connection with pre-employment medical examinations. The exposure is something that may cause dermatitis. I take it from the question that the problem of allergy arises. Do you recommend patch tests in conjunction with pre-employment exami nations to determine an cmp!oyee`s pos sible allergy to the exposure? DR. CRANC'H: In general, I would say you would hardly he warranted in con ducting patch tests on all applicants for employment. Where we have a known material to which the employee is being exposed that very commonly produces an allergy reaction, it might be advisable to use such a filter. Patch tests are not 100 per cent infallible, and they are not altoether simple. They have to he very care fully given and very carefully interpreted. For that reason, they are not an integral part of an average preliminary agreement upon examination. They might he quite misleading. A D JO U R N M EN T