Document MMXZ1vg8VDKrkY1ZJMNDR1rML

Surgeon General H. S. Cunning, United States Public Health Service, Hashington, D. C. January 17. 1926. D e a r ;S i r : The committee appointed by you at the request ox" the confer ence held in Washington May 2 0 , 1 3 2 5 , was directed to present to yon "if possible by January first next, a statement as to the health hazards involved in the retail distribution and general use of tetr?.-ethyl lead gasoline motor fuel". As soon as practicable after its appointment, the committee met in your office for organization and for discussion of the procedure to be followed in carrying out its instructions. The msnbers of the committee familiarized themselves, as far as possible, by conferences and by reading, with the existing data bearing upon tlie subject and upon lead poisoning in general. They had access to xko stenographic report (See Public Health Bulletin ITo. 1 5 3 ) of the ad dresses and discussions which took placo at the conference of May 2 0 , and subsequently they made a personal examination of the plant at Deep Water, 11. J. for the manufacture of tetra-cthyl lead, and of one of the stations ax which the ethyl fluid is mixed with gasoline. Ethyl gasoline was first placed on sale February 1 , I923, and its sale was voluntarily discontinued May 5 > 3 9 2 5 , about 3 ^0 ,0 0 0 , 0 0 0 gal lons of ethyl gasoline being distributed during this period. Serious cases of poisoning occurred among men handling load tetra-ethyl and ethyl fluid in the States of New Jersey and Ohio. As far as the committee is aware these accidents had all occurred in connection with the manufacture ana blending of concentrated tetra-ethyl lead, arid threw no direct light upon the problem specifically laid before us -- that of the retail distri Taution and. general use of ethyl gasoline. The valuable experiments re ported by the U. S. Bureau of Mines and by investigators at Columbia Uni versity and others yielded important results, but we felt that the crucial test of the situation must bo derived from actual experience in the use of ethyl gasoline under practical conditions of operation. It was therefore decided that the committee should make a direct investigation of the question submitted to them, planning the work on as extensive a scale as was possible in the time allowed. Fortunately this mode of approach was made feasible by the fact that ethyl gasoline has been in constant use as a motor fuel in certain parts of Ohio for several years; and although the production and distribution of tetra-ethyl load and ethyl fluid had been suspended by the voluntary action of the manufacturers, pend '* ing the present investigation, it was known that in the region indicated, a /' ) supply of ethyl fluid was still in the hands of certain consumers and would / be continued in use. We were thus presented with an opportunity of .studying a fairly large group of individuals who had been using and handling ethyl gasoline and of comparing the findings upon them with the examination of a similar group employing gasoline free from lead. In several conferences, the committee, with the assistance of Surgeon General Gumming and Surgeon L. B. Thompson, U. S. Public Health Service, in charge of the section of Industrial Hygiene and Sanitation, for mulated a general plan of investigation. The actual conduct of the work was entrusted to Doctor J. P. Leake, Surgeon, U. S. Public Health Service, who at once organized a corps of workers and began observations upon certain groups of individuals in Dayton and Cincinnati. The committee desires to express its appreciation of the cordial cooperation extended to this group of observers by both the employers and workers in the garages selected for the investigations. After all the preliminary arrangements had been com pleted, the work was pushed with great vigor during the autumnmonths, and on December 1 3 , Doctor Leake presented to the committee a fullreport of tie results of his study. The Committee wishes to express its great satisfac tion with the promptness, energy and ability with which these investiga tions were carried out. The general character and scope of the work may be summarized briefly as follows: Two hundred and fifty-two individuals were studied. They were all adult males, and fall into five groups. 1 . Group A, a control group, consisted of thirty-six men who were employees of the City of Dayton. Their duty was to drive cars during the working day. In these cars the gaso line used contained no lead. The cars were housed in the municipal garage, which in the report is designated as the Dayton Control Garage. 2 . Group 3 , a test group, consisted of seventy-seven men who / wire employees of a public service corporation in Dayton, 7and whose duties were similar to those of Group A. The cars that they drove, however, used ethyl gasoline, and this fuel had been in' constant use in this service since July, 1 9 2 3 - The garage in which these cars were housed is desig nated as the Dayton Test Garage. 3 - Group C, a control group, consisted of twenty-one men. These wore employed as garage workers in the Dayton Control Garage or in a similar control garage in Cincinnati, or as gasoline fillers at service stations or on trucks delivering gasoline in Dayton and the-adjoining region. In none of these garages, service stations, or trucks was gasoline containing lead used or handled. U. Group D, a test group, consisted of fifty-seven men. These were employed as garage workers in the Dayton Test Garage or in a similar test garage in Cincinnati, or as gasoline fillers at service stations, wholesale gasoline plants, or on trucks delivering gasoline in Dayton, Cincinnati, and vicinity. The duties of these men were similar to those of Group C except that ethyl gasoline was handled in the garages, stations, and trucks. 5. Group E, a control group, consisted of sixty-one men employed in two industrial plants of entirely different character from the foregoing in which there was known to be a serious exposure to lead dust. Numerous cases of lead poisoning had occurred . in these plants. This group was selected to serve for what nii^ht be called a positive control or check in regard to the validity of the clinical and analytical methods used in the study ox the individuals of Groups A, B, C, and D. Methods used: Zach individual was subjected to a careful clinical examination, and in addition, smears were made from his blood and a specimen of his feces was collected. The blood smears and the fecal specimens were sent to Wash ington to be examined by trained experts for stippling of the red cells and for content in lead. The examination of the feces for load was made by chemists who had been especially trained in the technique of the method. The blood examinations were made by a group of skilled observers, and were arranged so that the counts in each case were checked by several workers. The clinical examination was conducted by four physicians. The first of those took a careful industrial history of each subject, and assigned to him a certain number. These numbers were taken at random. Thereafter -his individual was recorded by his number, and none of those making the subsequent examinations or the laboratory tests know whether or not the iniividual had been exposed to ethyl gasoline; nor, in fact, did any ex aminer, except the ono who took the industrial history, know to which group tile individual belonged. After talcing the industrial history, other examiners made a thorough medical examination, including a medical history, hemoglobin extimation, red-cell count, blood pressure records, visual acuity tests, urine examina tions, etc.; and finally a determination, by a special method devised for the occasion, of the muscular strength of the extensor and flexor muscles of the forearm. ubilo all of the examinations wore made with as uch care as possible, special attention was given to three methods which, it was hoped, would yield quantitative data of an objective character. These were, first, the determination of the amount of lead in the feces,as an idex of lead in gestion or absorption; second, the estimation of the numberofstippled red cells, which, in the absence of other causes,night also be considered as an index of lead absorption; third, measurements of the strength of the extensor muscles of the forearm, as an index of lead poisoning. The two first methods yielded results ox positive value, but the last was practically negative so far as the present investigation is concerned. When all the data had been collected, they were submitted to study and statistical analysis by Doctor Leake and his collaborators, and the results were presented to the committee in the form of a detailed report '* containing a description of the methods used'', tabular summaries of results, ) and protocols of the findings for each individual studied. This report / will be published in full by the Public Health Service. So^ far as the clinical examinations are concerned, it may be said that they failed to give any decisive indication of lead poisoning among the chauffeurs or workers in garages in which ethyl gasoline was used as a motor fuel (Groups B and D). ' The median time of potential exposure among these men approximated two years, and this negative result, therefore, holds good only for a period of this duration. It should be added that in Group S, comprising workers in industrial plants in which there was a known and serious exposure to lead dust, definite clinical symptoms of lead poisoning were revealed, although Footnote: Tho only injury "observed was acute irritation of the eyes in^a few cases, due to getting gasoline into the eyes. This occurred both with ordinary gasoline and with ethyl gasoline but was perhaps more severe in one case due to the latter. This case is mentioned specifically in the full report. these workers had been exposed for shorter periods of time. More significant results were obtained from the analysis of the feces and from the microscopic examination of the blood smears. These results are presented in condensed form in the accompanying graphs, and tables. (Graphs 1 to U and Tables A, 3 , C and D.) Graph 1 and Table A represent the amount of lead found in the feces of the individuals of Groups A, 3 , C, D, and E. The figures along the abscissa of the graph give the amount of lead in milligrams per gram of ash of the fcccs, from 0 . 1 mgm. to 3 mgm. The ordinates represent percent ages of the workers in each group. It will bo soon that in Groups A and 3 , representing drivers of cars, one using gasoline without lead and the other the ethyl gasoline, the amount of lead in the feces was practically idonti- * cal. yhe exposure of these men was mainly to the exhaust gas from the Rotors/, and it would appear that in Group 3 , using the ethyl gasoline, there was no positive indication of increased absorption of load. The fact that in Group A, some lead was also found in the feces, shows that these men 'were exposed to load from some other undetermined source. In this connection it is to be noted that twenty examinations wore made in Washing ton by the same methods of the feces of ten of the workers in the Hygienic Laboratory of the U. S. Public Health Service. These workers had had no Inown exposures to lead but their feces showed at each examination small amounts of lead ranging from 0.0^7 mgm. to 0.290 mgm. per gram of ash of the feces. In what might be called normal feces, therefore, lead may bo present, from, accidental exposures of one kind or another, in concentrations not differing materially from those found in Groups A and 3 . In Group C, representing the garage workers and gasoline handlers not exposed to ethyl gasoline, there is an indication of a slightly greater ex cretion of lead. In the control garages and repair shops, as will be shown later, there was a perceptible amount of lead in the dust upon the floors and benches. In Group D, representing the garage workers and gasoline handlers using ethyl gasoline, there is a still further increase in the amount of lead excreted, although the number who showed excretion of as much as 0.3 mgn. per gram of ash is small (15 per cent). It seems probable that this increase was due to the 'use of ethyl gasoline, since subdivision of this group into two classes, those with a lesser exposure to ethyl gasoline, as regards time and intensity, 31 & 2, and those with a greater exposure, Dp end 4 , indicates that in the latter there was greater excretion, as is shown in Grap 2 and Tabic B. In Group E, as would be expected, there is evidence of much greater ingestion or absorption. Over SO per cent showed more than 0 . 3 mgm. of load for each gram of ash of the feces, and in some cases the lead was present in concentrations as great as 3 mgms. per gram of ash. Graph 3 (see Table C) gives curves indicating the number of stippled cells found in the blood of the workers in Groups A, 3 , C, D, and E. The ' .bscissa in this case represents the number of definitely stippled cells per 100,000; the curves are plotted for the valves 1 to 2 per 100,000, 3 to 6, 7 to 20, 21 to 100. . Hero again the results for Groups A and 3 are practically identical. In each group a small number, twelve per cent, showed definite stippling. ho examinations of persons who are neither drivers of cars nor garage / workers are available, carried out by the samo observers using the same method. It is not possible to say whether the slight degree of stippling observed with Groups A and 3 possesses any significance, but it seems to be clear that the members of Group 3 , exposed to the exhaust gases from engines using ethyl gasoline, showed no noticeable increase in stippling as compared with Group A. In Group C there is a distinct increase in the percentage of workers showing stippling, and this increase is more marked in the workers of Group D. These results, therefore, corroborate the findings from the analysis of the feces in suggesting a beginning storage of lead in these two groups. That the greater indicated storage in Group D is connected with the use of ethyl gasoline seems to be borne out by the curves shown in Graph 9-, (Table D ) , in which the curves are plotted for the two classes of D referred to abovo, the workers with the greater exposure showing a very slight increase in the percentage of those exhibiting definite stippling. The curve for the workers in Group E is of an entirely different character. Over 90 per cent showed distinct stippling, and in most, of these cases ' / the stippling was relatively very abundant. Inquiry into reported cases of injury resulting from the use of ethyl gasoline. . . '^ So far as the committee could ascertain, all the reported cases of fatalities and serious injuries in connection with the use of tetra-ethyl lead have occurred either in the process of manufacture of this substance or in the procedures of blending and ethylizing. It seemed desirable to institute an inquiry in the region where this investigation was made, and where ethyl gasoline had been employed as a motor fuel for the longest time as to possible cases of injury resulting from its use. All the work ers examined were questioned, therefore, in regard to their knowledge of cases of possible injury, and inquiries were made in the Dayton and Cincin nati districts among local health officers, physicians, public health .:ksrs, and labor leaders. The few cl-s.es obtained from this inquiry were -30sigated in detail, but the results were negative, ho positive evidence all be obtained of harmful effects attributable to the use of ethyl gaso- erv?tior.3 uoon the lead in the dust ana air of the garages investigated noon the amount of carbon monoxide. In addition to the examinations made upon the workers themselves, some aon were collected in regard to the amount of lead in the air and dust of .-o garages and work rooms, and also in regard to the concentration of car'u monoxide. These observations were made during October, 1925, and owing : :ha 'unusually cool weather prevailing during that month, the doors and innews wore closed during most of the day. The conditions regarding ventiatior. were these to be expected for winter rather than summer weather. The everal methods employed in this part of the investigation are given in de-3.1 in .the'full report. The findings obtained are summarized in the ac:-mpanying tabular statements for the several garages investigated as well 3 f o r oho industrial plants in which there was a serious exposure to lead asts. This pfert of the investigation was not so extensive as was desired, owing to the shortness of the time allowed, but it is evident from the re sults obtained that some lead was present in the rdr of the garages and work rooms whether the gasoline used contained lead or not; acid in the sweepings of dust from the floors and benches there was a distinct amount of lead pre sent, the figures running from 0 . 3 2 mgns. to 2 2 - 3 1 mgms. per gram of dust, according to the time and place of the gathering of the sample. It would seem probable, therefore, that in all garages in which automobiles are being handled and repaired, the workers are constantly exposed to certain amounts of lead dust, and this fact would tend to emphasize the importance of provid- -ic ing such, rooms with adequate ventilation, and of keeping both the floors and the benches as free as possible from the accumulation of dust. Owing to the incompleteness of the data, it is not possible to say definitely whether the exposure to lead dust was greater in those garages in which ethyl gaso line was used. It is very desirable that these investigations should be continued. rwvN i the basis of this investigation, the committee feels that the fol zing general conclusions are justified: i Drivers of cars using ethyl gasoline as a fuel and in which the concentration of tetraethyl lead was not greater than one part to 1500 parts by volume of gasoline, showed no definite signs of lead absorption after exposures approximating two years. Employees of garages engaged in the handling and repairing^of y automobiles and employees of automobile service stations nay show evidence of lead absorption and storage, as indicated by the lead content of the feces and the appearance of stippled cells in the blood. In garages and stations in which ethyl gasoline was used, the amount of apparent absorption and storage was somewhat increas ed, but the effect was slight in comparison with that shown by workers in other industries when there was a severe lead hazard (Group E) and for the periods of exposures studied was not suffic ient to produce detectible symptoms of lead poisoning. In the regions in which ethyl gasoline lias been used to the greatest extent as a motor fuel for a period of between two and three years, no definite cases have been discovered of recogniz able load poisoning or other disease resulting from the use of ethyl gasoline. g 01729 -II- In view of these conclusions your committee begs to report that in their opinion there are at present no good grounds for prohibiting the use of ethyl gasoline of the composition specified, as a motor fuel, provided that its distribution and use are controlled by proper regulations. The committee feels that the formulation of specific regulations in regard to the manufacture, distribution and use of tetraethyl lead, ethyl fluid, and ethyl gasoline for adoption and enforcement by the several States belongs properly to the office of the Surgeon General of the Public Health Service. In an appendix to this report, attention is called to certain suggestions which have been made in the course of the discussions of this committee and which it is believed should be taken into consideration in making such re gulations. * In conclusion wc beg to say that we are conscious of the fact that the conclusions to which we have come^in this report, although based upon most careful and conscientious investigations, arc subject to the criticism that they have been derived from the study of a relatively small number of indi viduals who wore exposed to the effects of ethyl gasoline for a period of _ time comparatively brief when we consider the possibilities in connection with lead poisoning. A more extensive study was not possible on account of the limited time. It remains possible, that if the use of leaded gasolines becomes widespread, conditions may arise very different from those studied by us which would render its use more of a hazard than would appear to be tae case from this investigation. Longer experience may show that even such slight storage of lead as was observed in these studies may lead eventually in susceptible individuals to recognizable lead poisoning or to chronic de generative diseases of a less obvious character. In view of such possibi lities the committee feels that the investigation begun under their direction must not be allowed, to lapse. The respective States would be dependent upon the findings of such investigations for changes in their regulations. 77ith the experience obtained and the exact methods now available, it should be possible to follow closely the outcome of a more extended use of this fuel end to determine whether or not it may constitute a menace to the health of she general public after prolonged use or under conditions not now foreseen. Outside the question of ethyl gasoline it would seen from this investi gation that wherever automobiles are housed together, there is an accumula tion of lead dust which may prove to be a source of danger to the workers involved, in addition to the hazards arising from tho production of carbon monoxide gas. The vast increase in the number of automobiles throughout the country mgjces the study of all such questions a matter of real importance from the standpoint of public health, and the committee urges strongly that a suitable appropriation be requested from Congress for the continuance of these investigations under tho supervision of the Surgeon General of the Public Health Service, and for a study of related problems connected with the use of motor fuels. W. H. Howell, Chairman, ... -A. J. Chesley, David L. Edsall, Heid Hunt, W. S. Leathers, Julius Stieglitz, ' C.-S. A. Winslow ' * TABLE A - PERCENTAGE C? PERSONS WITH MORE THAN ONE TENTH MILLIGRAM o? LEAD PER ORAM OF ASH IN PECES IN THE EXPO SUBS GROUPS A, 3 , C, D AND E. MILLIGRAMS OF LEAD PER GRAM OF ASH r--11O OO O O 1-4 .101 ..300 .3 01 1.000 3.001 & Over A 29 6 - - 3 32 2 - - C l+l 6 - - D 56 13 2- TJ-aIi 15 '49 29 5 7' TABLE 3 - PERCENTAGE OF PERSONS WITH MORE THAN ONE TENTH MILLIGRAM OF LEAD PER GRAM OF ASH IN FECES IN GROUP C AND HALF-GROUPS El- D2 AND D-3-DU. MILLIGRAMS OF LEAD PER GRAM OF ASH .101 .300 .3 0 1 1.000 1.001 9.000 C 1+1 6 - D1 and D2 (1) 3k s- D3 and DU 57 IS k 3.001 & Over - - -- (1 ) D 1 and D2 are the two quarters of exposure group D which had less exposure to ethyl gasoline and ethyl fluid and D3 and Dl+ are the two quarters which had the greater exposure. TA3 LE C - PERCENTAGE 0? PERSONS SHOWING DEFINITE STIPPLING OF DIFFERENT DEGRESS IN EXPOSURE GROUPS A, B, C D AND E. ' STIPPLED CELLS PER 1 0 0 , 0 0 0 RED CELLS 1-2 R- 6 7-20 21 - 100 Over 100 A 6- 3 33 9 3 - -- C 19 5 - -- D 28 9 9 - - E 10 13 13 26 31 (' TA3 LS D - PERCENTAGE OF PERSONS SHOWING DEFINITE STIPPLING . OF DIFFERENT DEGRESS IN GROUP C AND HALF-GROUPS D 1-D2 Aim DVDU. i STIPPLED CELLS PER 1 0 0 , 0 0 0 RED CELLS 1-2 3 - 6 7 - 20 21 - 100 C 19 D1 and D2 (1 ) 28 58 '-"IO - - 23 sind D^r 29 11 8 -- Over 100 - mm (l) D1 and D2 are'the two quarters of exposure group D wnich had less exposure to ethyl gasoline and ethyl fluid and D3 and D+ are the two quarters which had the greater oxposure. s/ r a 6 e cc ,,so u- .'-ai , ah\ / c v s n * ov Ohr Tf.VrH J O F L z o . 4 . ?A, A>* `. Cf = S h /A/ /C C i2 5 g y ^ a , X J A> S J  f i S OQ r> O' _ < V r / >/ " ' 3 a ) 9 ^ / 7c/ cZ/ J- S J O > y Z:7 %C K H J. f C) 5/ 5X> / QA1 J C J ? `O - -V .7 7 ^ 7 --