Document b52G7d6B7K7XmjNEN46kKMm3Z

In la n d S te e l Company - r nmmomtmcmTimm oor vwams momf mmwemms*t.mastmm*mA&mwso&exM&mrtexDcA&mo p tm l ait * An inspection of plant operations made in. the company of Dr. Kamer sad various members of the technical and production staff of the plant provided a fairly coisprehehslv grasp of the problems under consideration* Detailed study of the data obtained by the analysis of the air of worloqooma and elsewhere oyer tbs period of the past year has served to fill out the picture further. For the purpose of aakiag the present interpretation of the situation these analytical results have been accepted at their face Talus* It met be pointed out, hoveror, that since these are the only quantitative data available, and since conclusions of far-reaching importance must b based upon then, it is neither vise nor safe to accept their accuracy without proof* For this reason I shall subse quently suggest the means of testing their validity* Certain General flonatderatlona the Significance of the. Analysis of Air for lead Content Shs - estimation of the. significance of occupa tional lead exposure by determining the lead content of the air is based on the' generally accepted principle that load poisoning ' in industry decor* largely'.''a* the result of the inhalation of:. .' dangerous quantities of partl.otd.ate lead which are present in., the atmosphere of workrooms* It has been observed, that if the concentration of lead particles in the atmosphere does not exceed certain levels* cases of poisoning either do-'not occur or are bo mild as to be of little or nor consequence. By reason of variations KE 0 013 3 8 7 in the methods of collecting analysing air samples, and because of variation .in such factors a the type of load compound and its degree of dispersion in the air* and because of many associated Mmp&tiomX enadltionn such as proveiiimg temperatures* length of the writing day.*, and steadiness of onploymont* the threshold Hilton for* dangerous load closure have boon m% at different levels by different. hygienic workers. At present it can bo said -that the general concensus of opinion, as veil as contain official and ccsii-.offloi.al agencies, favor a pemissaiblc concentration soievwhere between 1 milligram and 2 milligrams of finely particulate load per 10 cubic no tora of air4 Ky ^crienoe ban Indicated, that the higher figure* l.o. 3 2 mg/10 M - is a safe one* regardless of the type and subdivision of the lead compound* provided general hygienic conditions are maintained In a satisfactory state in industrial plants, and provided medical supervision serves to eliminate the. definitely unfit worker from the plant-population. jfode of Estimating the glimlflcanoe of Lead Exposure. . Hi provisional character of the statement . above suggests that air analyses as. the solo method of evaluating occupational load closure leave something to be desired. Such* unfortunately, is - fee ease* She difficulties' of sampling the air of workrooms arc considerable* in that variability and periodicity in the operations.,; changes in, plant equipment and ventilation* and .shifting weather conditions introduce many factors which met be checked! - the methods of analysis of samples mot be of the utmost precision*''and such precision is not easily obtained round industrial plants with contaminated atmosphere* , KH* 0013388 >* jJ ** Add to these technical difficulties the fact that the load absorption of workmen underj*; given sot of atmospheric conditions is determined by the length of their working hem** in a specific area and by the character of their respiration during that period, 'The rate of pulmonary ventilation Varies from 5. liters per admit* to 25 liters per minute* A,c* from 8*# cubic metaro to 12 cubic meter*. por'd hour Morhing day* dependent upon the degree of exertion required by the occupation, Add the additional variable that relatively course particles never roach the lung tissue but arc trapped in the upper- rcsplmtory. tract and arc subsequently swallowed (and partly absorbed in the alimentary tract), while finely divided pariiolois may bo so. email as to behave like a gas end so be breathed, out Ih large part after once having been inhaled, Tax1 the problem can be seen to become a complex one, with not wholly pradietable results, In addition to the00 considerations* which can be covered by introducing a large factor of safety into the level accepted as permissible (m soma ,. have don by urging the adoption of the concentration of X sag/10 -VL9 'ac'the'safe level}* there is the problem of organic disease among;-. . .the workmen as- a factor in. susceptibility to- lead exposure, Xt is . well, known that general vascular dlccacc* end especially liver disease arc important footer* In succcptiMlity to lead poisoning,. . .while"-certain other types of illness are m difficult to differen tiate clinically from the effects of lead absorption m to provide cases which must be handled, m though they were load poisoning* If once the. .pocolMlity- of lead intoxication be recognised or believed to be present* ' There is always the problem of deciding which condition la responsible for illness or disability* and Kir 001.3389 h -* when tills decision ha bees sals* "the other la likely to be regarded as eoatributx>ry. Adjuncts to Air Analyses It mat be Apparent* thenfore*, that some additional measures of hygienics control' mat be exorcised* not only to avoid hazardous lead exposure* but to obtain more or lea continual proof that such exposure is being currently avoided. This can bo don in the opinion of the writer only by means of regular- and adequate medical supervision of workman. Such supervision mat, (1) exclude the physically unfit, i.e. those to whom the lead exposure of the occupation will probably be hazardous: (2) mahe.-such observation on the- exposed as to determine whether or not they are actually absorbing significant quantities of load; (3} aain.tain ouch records as will prove 1he . adequacy of the supervision* (&) Chech carefully every case of Illness so as to exclude lead as a factor when it la not, by arriving at an. acceptable diagnosis of the actual nature of the . illness. Hot to go Into the details of procedures to accomplish the above purposes, suffice it to say hero that preemptoyaent and periodio physical examinations of a fairly comprehensive type are required, and that blood examinations of a standard type must be made and recorded* In addition, the urinary and fecal lead excretion of at least, a tm representative workmen should be determined at intervals* and,in-cases fcimlating plumbic, study of the lead excretion should be made promptly* Bio above recojamndatlona are predicated, of course, upon the existence of hazardous lead exposure, or upon the existence- of lead exposure which ha not been- proved to be K 0013300 harmless, and which, therefore, raay he under suspicion, In a new Industry, or la a new procedure Involving lead in an old Induetry, lead exposure will usually bo regarded an hazardous for purposes of compensation or litigation, until it has been proved otherwise. Plant Conditions m Observed and Otherwise Demonstrated. On the basis of the observations made, the lead hazards of the plant procedures seem to range themselves In order of decreasing importance as follows; (l) lead exposure during the pouring and cooling of lead heats; (2) lead exposure at the rolling mills* which apparently Is at its worst at the blooming mill, and la less but probably significant at other mills; {5) welding and * scarfing** procedures are both associated with a dangerous production of fume. (It is apparent that the hazards of this type of steel do not end at the site of manufacture but extend Into the general field of use* In 00 far a3 weldingand/ or other high-temperature processes are Involved.) The lead exposure associated with the pouring of ingots is being handled to a very large extent by local ventilation and by the use of hot tops* and "hot topping* materials. The analytical data Indicate, however, that the control Is not wholly adequate, in -that dangerous concentrations of load can be found at times, although perhaps not for long, in the immediate vicinity of the .Ingots, 'Unfortunately, there are no'-data on the extent of the veiltalizatlon'Of. lead during the removal of the "hot tops" and molds and for some time, afterward. The exposure associated with the various rolling procedures, and especially that at the blooming mill, is not under control, in my opinion, and is likely to give considerable diffi culty. The probl^a of control* here is admittedly a difficult eri-O.o 3X -Sone, technically* but acme type of local ventilation would appear to be required. The exposure, which arises from "scarfing** is, 1 think* a serious one* If continued long enough, and that associated with welding belongs in the asm category. * With the single exception of the exposure of pouring the ingots, which can readily be controlled by the im provement of present ventilating facilities, the other operations offer opportunities for exposure that will be difficult to control and that in my opinion will produce lead poisoning among workmen, and would* in fact, have done so, except for the Irregularity and' Infrequency of the operations. It would be -surprising to me if \ workmen who have had the longest and most frequent expo mire in the several types of occupation did not show a distinct elevation in their load excretion,. Hecomenda tiona So far as plant operations arc concerned, the writer believes that the lead exposure can be controlled and kept within oaf limits, (As to the significance of that beyond the confines of the plant* only time and investigation will serve to determine* but the outcome should probably not be left to chance,) Control, within the plant, is an engineering problem, Involving the removal of lead from the plant atmosphere to the extent required for safety, j la general, it would be advisable to remove the lead by collecting it, rather than by merely diluting it. This may or may not be feasible In terms of production costs, but. it may well be found that the collection of the lead fume would reclaim enough metal to pay in considerable part or in whole,, for the equipment required to collect it, HE 0013392 ~7~ ^Saiwref may ba the means of reducing the load exposure, a continual study of conditions should bo carried out so sr as to establish the effectiveness of the measures of control* In view of the Importance of the air analyses in arriving at present conclusions* it is believed that the methods of analysis should be subjected to rigid Chech* so as to eliminate any question ' as to their precision, fills can be done in a variety of ways* and In order to make a start In that direction, it la suggested that a atr*ica of samples of known lead content be prepared in this laboratory and sent to the plant analyst for examination and'report to us* On the basis of the results obtained further Chech may be made no needed. In recognition of the fact that whatever oapoouro has existed over the past year will have loft its record in the form of lead absorbed by exposed workmen, it is recommended that a group of workmen be examined as to their lead oxerstIon./ -Thera are several ways by which this could be dona, each involving a somewhat different amount of work and cost, (1) One means of approach would be to select two or more men whoso-lead exposure has been maximal, sending them to mo In Cincinnati for -complete examination and de termination of the extent of their occupational lead absorption. It would require from 2 to 4 days, dependent upon the initial analytical results, to obtain the desired information* the cost involved in such a study would be the traveling expohee, moderate hotel expense, a nominal examination fee of 10,00 per person to cover the cost of blood examinations etc., and the expense of analyses on the blood, the urine and the feces at $$,00 per analysis, (the actual proportional cost of operation of our analytical, labora tory). (2) A second and better method involves the selection of a & 00.133,93 "-------------------------------------------------- ' ................................... ............______________________________________________________________________ group Of men representative of the wonat exposure believed to exist In_the plant* and the eantslnatlon .of these men on the day Immediately following- the earryinir out of the operations associated with exposure. "These aen might well be given thorough physical examination by the plant physicians, with reports forwarded to me, the examination to Include making duplicate blood smears, one set of which is sent to me for examination, one sot being studied at the plant laboratory by the present methods employed there. At least 10 employees (the moat severely exposed) should collect samples of their feces on the day following their exposure, and samples of their urine over a period sufficient to obtain at least 2 liters of the latter. (Containers for these samples, and instruc tions for their collection will bo provided by me, and in each case the samples met be collected at the homes of the employee rather than at the plant, A successful technique for this type of sampling has been developed in this laboratory.) This method of procedure would serve to determine the general order of magnitude of the actual exposure in the jobs carried out by the men so examined, 'She coat, here, would be the express charges on the shipped con tainers and the camples, the expense of examining the blood smears (determined by the actual coat of a technicianrs time), and the expense of the analyses at #5*00 per analysis, (3) A third method would be valuable m a measure of'the comparative magnitude of the - total lead exposure which has occurred up to the present in the plant operations, It* therefore, would be. an attempt to determine how much load absorption ha taken place among the moat severely exposed men. It would be lean valuable than method #2 as a measure of the actual exposure associated with a typical day *s work* It-, consists in carrying out exactly the same procedures listed above - K .tO i -i .. .. ____________ . ..... .... -: -. . : ml _ in the oaae of nan who have been engaged at this type of work for 3ome months, but at a time some days or, if possible, 2 weeks after a day of actual exposure. (4) A'fourth method would be the careful selection of mm representing all of the types of work that present opportunities for exposure, studying them systematically ' and perhaps repeatedly by clinical and analytical methods both in relation to a. day of exposure and between exposures, so as to obtain comprehensive Information as to the extent of their exposure and their absorption* Such data once collected could be used in comparlaon with subsequent observations to determine the extent of the hazard arising from changes in plant operations or from increases in production* and to check the adequacy of improved measures of control. The cost of this type of study would depend upon the means of doing the clinical work, 1** whether done by plant physicians or by our staff, - the number of blood smears to bo examined, and the nuraberof analyses to bo carried out at the rate indicated above. Obviously the us of my of the methods mentioned above, some combination of them* or a choice among them, may well depend upon a number of/factors, such as cost, convenience, or the- i urgency of obtaining information. Moreover, it would not be possible at this time to divert the efforts of the clinical or technical staff of this laboratory into the immediate accompli shment of such a pro- . gr-aa as is contemplated in; method $4-. in view of the apparent significance of this hygienic problem, however, and in view of our keen professional interest In the significance of various types andmagnitudes of occupational lead exposures, we should feel constrained to carry out such early observations m might b mutually agreed upon as essential. la this connection It would seem to be the better part of wisdom, pending careful check of the adequacy of the air analyses, K F 0 0 .1 3 0 ;); --- ... ... ... .. | mm.................... ................. . :- V- * -> : o>,- ~ 10 - to determine the extent of the actual occupational lead exposure of uorftoen up to the present time* in at least & fm carefully selected instances, lest some actual or alleged case of poisoning should develop before any adequate information had become available. In the present situation, almost any type of illness among the plant personnel' might be called lead poisoning, by physicians. In that case, granting that such a diagnosis might be incorrect, proof of its incorrectness uould be required to absolve the industry from refipanslbility./For this- reason it is believed that cases of illness of any type among the exposed per sonnel should be given complete and'careful clinical study, and that analyses of blood and excreta should be carried out as an aid to differential diagnosis and as proof of the- significance or insignificance of the load exposure._ Arrangement can be made to carry out the analyses involved in this recommendation if it seems desirable that they be done in this laboratory. Signed! Robert X. Ic^hoeV **, D. Director, lettering Laboratory of Applied Physiology College of Medicine University of Cincinnati nr 0013396