Document ymjnGd6GbjDXzJvGyRq73zV6E

A STUDY OF THE HEALTH HAZARDS associated with THE DISTRIBUTION AND USE OF ETHYL GASOLINE - by - Robert A. Kehoe, M. D., Frederick Thamann, Karl Y. Kitzmiller, M.D., R. L. Crudgington, M.D., Dillard F. Machle, M.D., Lester Sanders, Jacob Cholak. April 1928 From The Eichberg Laboratory of Physiology, University of Cincinnati, Cincinnati, Ohio. (Printed in U.S.A.) X INTRODUCTION The Committee appointed by the Surgeon General of the United States Public Health Service in 1925, to examine into the possible public health hazards associated with the distribution and use of gpsoline con taining tetraethyl lead, recommended, in their report of January, 1926, that further investigations be made.'*' As it appeared, from their in vestigation, that there was no evidence of immediate danger to the public health, it was thought that these necessarily extensive studies should not be repeated at present, at public expense, but that they should be continued at the expense of the industry most concerned, subject, how ever, to the supervision of the Public Health Service. The following study was undertaken in the Eichberg Laboratory of Physiology, in the University of Cincinnati, at the expense of the Ethyl Gasoline Corporation. The selection of subjects, and the general methods employed, were planned in conference with representatives of the Public Health Service. The work proceeded under their observation, but, except for suggestions, without their aid. All of the original data was submitted to the Public Health Service, and the following report was pre pared with its co-operation. U. S. Public Health Service: Public Health Bulletin No. 163, 1926, p. 110. 2. II SELECTION OF SUBJECTS Table 1 indicates the numbers and the classification of subjects which have been utilized in the present study. Special attention was given to the selection of control subjects. An analysis of the data obtained previously indicated the advisability of increasing the number and diversifying the types of these. It has been shown by this laboratory2 and b y the United States Public Health Service 3 that industrial employees in general in this country are exposed to lead compounds to such an extent as to cause th6 regular excretion of lead in urine and faeces. It becomes important to determine in what degree this is due to industrial exposures, unrecognized and unrecorded by the subjects and examiners, and in what degree it is due to the existence of lead on the surface of the earth, in food materials, in wrater, etc., in such a manner as to gain entrance into the average individual with no industrial experience. It might be argued that the general occurrence of lead in city streets, and on the earth's surface is due to the effects of the use of leaded gasoline, and that it represents a recent development. Evidence to 4 the contrary is available in the form of data obtained prior to the wide distribution of Ethyl Gasoline, from a city (Columbus, Ohio), in which leaded gasoline had never been distributed. In order to obtain further information on these matters by approaching them from different angles two groups of subjects were selected. One of these was a class of seventy-one students writh essentially no industrial experience, the other a group of ^ Robert A Kehoe and Graham Edgar: J.A.M.A. 87, 1926, pp. 2081-2084 ^ U.S.Public Health Service: Public Health Bulletin No. 163,1926, p,107. * Robert A. Kehoe and Graham Edgar: Loc. Cit, 3 forty-two tank wagon drivers who had been handling gasoline for a number of years, without recognizable lead exposure, in a community in which Ethyl Gasoline had never been used. Unfortunately, for our purpose, the latter group refused their co-operation in providing samples of urine and faeces for analysis, after having agreed to do so, and after having pre sented themselves for examination. This event occurred so late in the progress of the work that it was impossible to.replace them with another group. Data are available on them in every respect except that of lead excretion, however, and are found to be of some valxie. The medical students came from various parts of the United States and their daily occupation and their manner of living exclude the likeli hood of their exposure for any appreciable period of time, to influences produced by the distribution of Ethyl Gasoline. Only three of those who drive cars had ever used Ethyl Gasoline, and their histories, with few ex ceptions (indicated in the tables of individual findings) showed a remark able freedom from exposures to lead. Seventy-two filling station attendants who had not handled or been exposed to Ethyl Gasoline were selected, with care to obtain as com plete correspondence to the test group as vra.s possible, in age, social status, and locality of occupation. No control group of garage mechanics was obtained. With the increasing distribution of Ethyl Gasoline., it has become practically im possible to secure a group of garage workers, for such an investigation, with positive assurance that they have not handled cars using Ethyl Gaso line. Therefore, the data on the control group of mechanics, listed as A4, have been taken entirely from the work done in the winter of 1926. There is evidence that the analytical results obtained in 1926 are not 4 strictly comparable to those obtained in 1927, but the variation in this case is not large enough to invalidate the comparison, for reasons which will appear later. There are three groups of persons who experience all of the means of exposure to the hypothetical hazards associated with the use and distribution of Ethyl Gasoline, and to a degree which greatly exceeds that with which the general public is concerned. These listed in the order of decreasing intensity of their exposure are, (l) garage mechanics who work on cars which utilize Ethyl Gasoline, (2) tank wagon and other bulk handlers of Ethyl Gasoline, and (3) filling station attendants who dis pense Ethyl Gasoline. The thirty-five garage mechanics, making up group B2, who have been working on cars using Ethyl Gasoline exclusively, were obtained after a careful search in all parts of the country in which Ethyl Gasoline has been used over significant periods of time. Ten of them have been employ ed in a public service garage in Dayton, Ohio, in which Ethyl Gasoline has been the exclusive fuel since 1923. The others were found in garages own ed by oil companies. Without doubt the number of mechanics who come in contact with a variable number of cars using Ethyl Gasoline has steadily increased, but the number of men who work exclusively on cars which con sume Ethyl Gasoline, is still small. They are to be found only in indus trial garages which employ a fleet of cars in their business and who use Ethyl Gasoline exclusively as motor fuel. The past year has added to this group a considerable number of those who have had a significant per iod of exposure. All who could be found were used as subjects. A number of these have been under observation over a period of more than four years. Furthermore the severity of the conditions of exposure has been all that 5 could be required for the sake of the problem at issue. During the months of December to March in which these men were studied, the ventilation of' the garages in which they were employed was at its worst, on account of inclement weather. Opportunity was afforded to appreciate the degree of exposure to exhaust gases occasioned by driving in and out, as well as the testing of a large number of cars in an enclosed space with no acces sory ventilation. In addition to exposure of this type, great enough to produce frequent but apparently not permanent symptoms from carbon monox ide absorption in this group of subjects, there has been regular exposure to whatever hazards result from the general care and repair of a large number of cars. The seventy-seven filling station men and the fifty-two bulk and tank wagon handlers of Ethyl Gasoline were selected because of the severity of their exposure to Ethyl Gasoline, and also because of the de sirability of maintaining the continuity of observations made in previous years on the same individuals. \ * \ra\ There is a great variation in the sV rity of the conditions of \. exposure to Ethyl Gasoline in different parts of the United States. This fuel has been marketed and used continuously in considerable quantity in certain districts for a period of five years. In other areas its continu ous use has been for much shorter periods and, in some cases, less than a year las elapsed since its introduction to use. Furthermore, variations in gasolines from different sources, and in various parts of the country, bring about a wide range of concentrations of tetraethyl lead required to bring the gasoline to a certain minimal anti-knock standard. There is by no means a strict uniformity in the lead content of the Ethyl Gasoline of a certain district, but there is a general tendency for a given district 6 to market gasoline obtained from a certain group of crude oils, for purely commercial reasons, which naturally tends to delimit the range of tetra ethyl lead concentration Dayton and Cincinnati, Ohio, were the points at which Ethyl Gaso line first appeared, and here during the first years of its use, the con centration of tetraethyl lead in the gasoline was at the highest level that has been used commercially, being approximately 1 part in 1300. The distribution spread into middle western and southern United States at an earlier date than elsewhere. The desirability of this region as a source of subjects is heightened by the fact that here the concentration of tetra ethyl lead in the gasoline still remains somewhat higher than is generally found in other parts of the country. Table 2 shows the length of time during which Ethyl Gasoline has been distributed in various large cities, illustrative of the districts lying in their vicinity. The period of discontinuance described in the table refers to the period of voluntary withdrawal of the product from the market by its distributors, during the progress of the investigation con ducted by the United States Public Health Service. During this period there were two areas in which the use and distribution of Ethyl Gasoline suffered no interruption. One of these was the region in which the in vestigation was carried on, Dayton and Cincinnati and vicinity, the other being in Savannah and Atlanta and vicinity. This Table also shows the range of tetraethyl lead concentration in the Ethyl Gasoline which has been distributed in various localities during the past year. Table 3 shows the distribution of the selected subjects accord- 5 U.S.Public Health Service, Public Health Bulletin No. 163, 1926, p. V. 7 ing to their locality. It will he seen that these subjects represent the persons whose exposure has been the most severe, from every point of view. In &ct, many of these subjects have experienced such a degree of exposure to tetraethyl lead, in addition to Ethyl Gasoline, as to disqualify them for use in a careful study of the influence of Ethyl Gasoline exposure alone, Such exposure came about in the following ways. When Ethyl Gaso line was first marketed, the concentrated fluid, Ethyl Fluid,- (approximate ly 60% tetraethyl lead) was distributed in small metal containers, which were attached, in a small measuring device, to gasoline hose lines at each filling station. Such cans had to be opened, placed in position, and re moved when empty, for reshipment to the consignor. This method of dis tribution was of comparatively short duration, but a large number of the filling station attendants (all those whose exposure exceeds three years) who make up the test subjects, have had from three months to a year of such exposure. In the case of the earliest tank wagon handlers of Ethyl Gaso line, there was the same type of exposure, by reason of the employment of a * now obsolete method of mixing Ethyl Fluid with tank wagon lots of gasoline. In a few cases this exposure was very severe indeed. It will be seen in the data of this study, as well as in those of previous years, that this exposure was significant, and may not be disregarded.. Nevertheless, these subjects have been included in recognition of their importance as examples of the effects of very much more severe conditions of exposure, than those in existence at present. The control group, C, consists of one hundred and twenty-two per sons obtained from industries with recognized lead dust hazards. These subjects have been studied during the past few months, both for the purposes of the present investigation, and in order to obtain data of general impor- KF 0018100 8 tance in connection with other problems under study in this laboratory. The subjects represent all degrees of intensity of lead exposure. There were no cases of marked lead poisoning among these men at the time of the examinations, and there.had been no history of lead poisoning in the plants in which they are employed, in the past few months. Such cases, though infrequent, do occur from time to time. Chemical analyses were made on only a portion of this large group, although the entire group was used for clinical data. 9 III METHODS OF STUDY 1. Collection of General Information: Experience had demonstrated the necessity for great care in ob taining detailed histories which would indicate the- existence or non-exis tence of previous or present exposures to lead on the part of all subjects. For this reason special care was taken in formulating questions and in tabulating the results of such questioning. Important industrial lead ex posures known to the examiners were made the subject of leading questions. The time of occurrence and the duration of such exposure, when found, was recorded, in order that accurate estimation of its significance might be made. One of the physicians (W.F.M.) was assigned to this portion of the work in order that the data might be uniform This examiner gave each sub ject a number, and entered this number, without the name, on the other examination blanks, and then assigned the subjects, without their histories, to the other examiners, who thus had no knowledge of the content of these histories . The same examiner carefully sought out the existence of symptoms, first in a general way, in order to avoid suggestion, and then by means of a series of leading questions, to stimulate the recollection of minor or past indispositions. It is difficult to estimate the importance of brief ly recorded information obtained in response to leading questions, but the are recorded on the supposition that the variations in response equal12e each other in several sufficiently large groups of subjects. Differ ences between any two groups of subjects arrived at on this basis must not taken too seri'ously, however, for one cannot fail to notice general 10 tendencies in certain of the groups, which indicate the necessity for con servatism in the interpretation of the results. Thus the men employed in an industry with a lead dust exposure generally minimize their symptoms in face of the possibility of unemployment, while young medical students are alert to the slightest subjective symptoms and are inclined to magnify them. As a general thing, the men 'who handle Ethyl Gasoline are not ap prehensive, in spite of the frequency with which their attention has been called to the possible dangers of their occupation. An occasional individual in this group, however, demonstrates some anxiety, which is very much heightened by the development of any type of illness or discom fort. A certain proportion of these men cannot fail to be impressed by the possibilities for injury to themselves, in the case of an occupation which is so rigorously investigated. On the other hand, the average handler of ordinary gasoline, and even the average garage mechanic who has no exposure to Ethyl Gasoline, scoffs at the idea that there is anything in his occupation which can cause*him any injury. The work of observing and recording the objective findings was subdivided among the three remaining physicians, one (R.L.C.) carrying out eye, ear, nose, mouth, throat, nervous system and skin examinations, one (K.V.K.) recording chest and abdominal abnormalities, and one (L. S.) carrying on the laboratory procedures. To a very large extent the findings were recorded in uniform terms, and so far as possible in quantitative term Unusual variations from the normal were referred to the entire group. Careful consideration of each case of recognized abnormality was given in such a way as to arrive at a conclusion on the clinical condition as a whole. Four cards were provided for the collection of data, essentially 11 like those used in the investigation reported in Public Health Bulletin No. 163. The observations in this case also were not limited to the sub ject matter of the cards. The cards are reproduced herewith, on pages 12, 13, 14 and 15 of this study. Tests of muscle strength were made on a number of subjects by means of an apparatus which is a slight modification of that described by J. P, Leake, and used by him and his associates in the investigation, re ported in Public Health Bulletin No. 163, pages 18 and 19. The data as obtained are recorded in the tables of individual findings. Nothing of consequence is demonstrated by them. It is probable that, if used more extensively in the study of persons exposed to lead dusts, Group C, a larger number of examples of wrist weakness might have been detected by it since some such conditions were recognized without it. No such cases of neuritic origin were found among the subjects in Groups A and B, though there were two examples of unilateral wrist abnormality due to previous cone injury. In our hands, there -was not such uniformity of results in successive tests of the same individual as to justify conclusions based on slight deviations from an average "normal" standard. Tests of vision were made at twenty foot distance, using Snellen card, the data on each eye being recorded, with a statement as to the use of glasses and their adequacy in correcting the error. The comparative dimensions of the visual field 'were tested by a rough method which con sisted in having the subject focus on an object directly in front of him, while another object was moved in along various axes. It is realized that this method is subject to criticism. It cannot yield reliable information of the existence of slight contractions of the visual field, and there is large opportunity for erroneous conclusions, as a result of uncorrected 12 HISTORY SHEET Ho. 1 Number Examiner's Initials Date Name Age Race Color Birthplace Marital Ages Children Miscarriages Date Stage Residence Other places lived in, with dates Place of Employment Type of work (exact description of nature and conditions) Length of Present employment and previous employment at same work Previous Occupations Dates Previous Lead Hazards Dates Painting Plumbing Carriage, Auto or Car Type Casting Smelting or Refining "Treating" Refineries . Storage Eat.Mfg. or Rep. Lead Burning Printing or Lithog. Mining Foil, Solder, Babbit Mfg. Previous Lead Hazards Dates Brass Founding Soldering Enameling Paint Mfg. Pottery Glass Polishing Cut Glass White Lead Rubber Garage Telephone or Telegraph Rep. Automobile Owner Gasoline Used Previous Illnesses with dates Repair Work Tbc, Malaria Rheumatism Tonsilitis Frequent Colds Lues. Gc. Convulsions Scarlet Diph Heart Disease Typhoid Asthma Significant Family History Remarks: K E 0018105 HISTORY SHEET (Continued) No; Number Examiner's Initials Sle ep Hours in Bed Dreams Restful Consumption (Milk per day (Cream (Water (Tea (Coffe e (Alcohol Date Disturbed Sorrel Movements -encency to Constipation xeeth Brushing Usual Weight General Health When Best Weight Frequency Cathartics Last Trip to Dentist Hour Recent Loss of Weight -aate of Tiring Headaches Recent Change Eye Trouble Taste in Mouth rains m Joints Character i . ' u scalar Strength Pains in Belly Appetite Character digestive Disturbances Skzn Infection or Eruption Polyuria Uervousness Nocturia 0>,her Complaints 'Uscle Strength (` ight Wrist Extensor Right Wrist Flexor Left 'Wrist Extensor Left Wrist Flexor 1 Time Swelling of Joint3 Cramps in Muscles Frequency Different Meals Nausea or Vomiting General Frequency General Weakness Hands Right or left handed 2 3 Average 14 PHYSICAL EXAMINATION SHEET No. 3 Number Seneral Appearance Nutrition Pulse Examiner's Initials Date Posture Mu scu 1ature Height Color of Skin (exact) Slood Pressure (Seated) Sclera Condition of Skin G-lands Condition of Skin of Hands Romberg Tremors Weight Glasses Eyes Muscles Nose Tongue Teeth (exact condition) Vision Pupils R 15/ L 15/ Near Sighted Sx 2Q Par Sighted Regularity- Ears Throat Audition Abnormalities Tonsils Gums \Cleanliness) Lead Line (Exact appearance Heart Apex Rate After 25 Hops 2 minutes after Pyorrhoea location) R . C .3. R.S.D. Lungs: K.i. _ r . L. Chest Diagnosis S. E. - R. L. L.L.B. - R, L. Abdomen Liver Rectum Spleen Gentalia Kidneys Reflexes biceps Triceps Abdominal Tendon Jerks Sensations Upper Extremities Lower Extremities Special Remarks and General Diagnosis Painful Tactile Thermal Kinesthetic 0018107 15 l a b o r a t o r y spiest No. 4 Number urinalysis: Quantity _. Examiner *s Initials Date Reaction (Methyl Red) Albumin (Heller's) Sugar (Fehlingis) Heat and Acetic Acetone (I'litroprusside) MicroscoDic 3 lood White Count Red Count Haemoglobin (Dare) Differential (100 cells) Poly. Neutrophiles Poly. Eosinophiles Poly. Easophiles Lymphocytes Endothelial Large Monenuclear irans ib ional Abnormal Stippling (Per 50 fields) Polychromasia -analytical Examination accurate Statement of Hours Required for Collection o f : Urine Faeces Constipation FAECES Vt dish dried faeces m dish f ash v/t dish 7irt . Pried faeces Yit ash Diarrhoea URINE Volume Cathartic (type) Lead Hgs. Mgs./gram of aah Analysis No. Lead Mgs. Mgs/Liter Analysis No. 16 refractive errors, as well as misunderstanding and non-cooperation in the subjects. However, it is unlikely that perimetric tests, carried out ac curately, would yield sufficient information to justify the expenditure of time. No noteworthy differences in the groups were found with respect to visual acuity or extent of visual field. Other central and peripheral nervous system reactions were test ed in each subject. Reflexes were systematically examined, tremors of all kinds and locations were noted, and the tactile, thermal, painful, and kinaesthetic sensibilities were investigated, with special reference to the skin of the hands and forearms. A fresh specimen of urine was obtained from each subject and ex amined at once. It was tested for its reaction, using a standard quantity of Methyl Red. This indicator was selected because its sensitivity to acid is sufficiently low to demonstrate urinary acidities which are on or over the border line of abnormality. Albumin was tested for by the nitric acid ring method and by the heat and acetic method in each case. Fehling's test was used for the determination of the presence of sugar, and the nitroprusside test for acetone bodies. Microscopic study of the urine was carried out only when indicated by the existence of chemical abnormalities. Erythrocytes were counted in only a few instances in 'which anemias were suspected by reason of other observations. There is no basisfor believing that valuable information could be obtained by counting the erythrocytes in the case of each subject. However, determination of tho haemoglobin of the blood was made on each subject. The Dare instrument was used for this purpose, the some instrument being used throughout the study. The readings were all made by the same individual (L. S.). 17 Leucocyte counts v,rere made on a few subjects in which this infor mation was desired for purposes of differential diagnosis These instances had no relationship to the primary problem. 2. Procedures of Specific Significance: Special care has been taken in the collection of the following three sets of data These data are objective, and they are quantitative, within sufficiently accurate limits. They are capable of being secured by uniform methods from all the subjects, and though they are variable as a result of processes which are not understood, yet they are more specifically related to the problem of lead absorption than are any others at our com mand . (a) Determination of basophilic stippling of the erythrocytes. Three blood smears were made from the blood of each subject. These were all made by one of us (L.S.) with as great uniformity of thick ness and distribution of erythrocytes as possible. Each smear was number ed and returned to the laboratory for examination. No fixative was employ- ed. They were inspected and the best ones of uniform thickness were select ed for examination. Staining was done by a method which has been in use in this laboratory for more thr year, - a method devised by R. L. Ware of exa Pennsgrove, New Jersey. The solution is prepared as follows: Methylene Blue 1.5 gms. 1% Sol.AlgiSO^g.KgSO^ in 509o aqueous CH^OH 0,5 cc 1% Sol. NaOH in Ch3OH 0.2 cc CH3OK 100.0 cc The smears were immersed in this stain for four seconds, and were 0018110 18 washed rapidly with 0.025% aqueous Sodium Bicarbonate solution. It is im portant for uniformity and clarity of staining to dry the smears very rapid ly. For this reason they were dried in a strong air current. The resulting stain is brilliant. The erythrocytes are stained a pale green and are sharply defined. The nuclei of neutrophilic polymorphonuclear leucocytes are deep blue. The criterion of the satisfactory quality of the stain is the relation existing between the pale green translucent appearance of the erythrocytes and the depth of the nuclear staining. As is the case with all blood stains, some little experience is necessary to obtain the best results with this stain. In our hands a large measure of uniformity of staining has been obtained, and the ease with which stippling is demonstrated has been gratifying. The basophilic granules are very dark blue in a pale green field. Foreign particles are readily recognized as such. All of the examinations fcr stippling were made by one of us (L.S.), whose experience and training in this work qualified him especially. A Zeiss microscope with lenses selected for their sharp definition, was used, a magnification of 900 diameters being employed. Fifty fields were examin ed with care to give close scrutiny to every erythrocyte in the entire field. In our opinion the examination of every cell in that number of fields is far more effective than the examination of the central portion of a great many more fields. Despite care both in making uniform smears, and in choosing the fields of most nearly uniform distribution of erythrocytes for observation, considerable variation in the number of erythrocytes per field occurs. The number per field averages about 250. Thus the examination of fifty fields implies a study of approximately 12,500 erythrocytes. No erythrocyte was counted as stippled unless three or more granules were present, and except as the examiner was entirely certain that true stippling existed. In some cases it became necessary to stain and examine more than one blood film to establish the facts. (b) Determination of Lead Content of Faeces (c) Determination of Lead Content of Urine The desirability of determining the lead content of both urine and faeces of all the subjects was indicated by the following considera tions. It has been found that the variability of results obtained in the analysis of faeces is greater than those in the case of the urine. This is not remarkable, in view of the opportunities for purely accidental contamination of food materials with lead from many sources. As an example of this we have found lead shot in samples obtained during the hunting season. Furthermore, the faecal excretion, as represented by a single ssimple, is not an adequate measure of the magnitude of the lead concent of an individual, because of the daily variation In the activity of the alimentary tract and the organs physiologically associated vd.th it. Perhaps such sampling errors are rendered insignificant in the study of a sufficiently large group of subjects. However, the faecal excretion does not represent only lead which has been absorbed, but rather that which has entered the alimentary tract from all sources, both external and internal. The chief value in the study of faecal excretion of lead is found in its ability to give evidence of the magnitude of present exposure to lead in the form of particulate matter which has been deposited in the mouth and nasopharynx, provided it can be ascertained with reasonable assurance that the quantity entering the alimentary tract from the outside is significant ly greater than that being secreted into it from the tissues- Thus, in 20 industries with a definite lead dust exposure, as in our Group C, faecal excretion of lead may be regarded as a measure of the existing exposure. Urinary excretion of lead is not subject to the same dangers of misinterpretation, nor are the sampling errors as great in studying it, as in the case of faecal excretion. It is undoubtedly a better criterion of lead absorption. Before such results may be accepted as an adequate meas ure of the magnitude of prolonged slight exposure to lead compounds, it must be determined whether or not the quantity of lead so excreted is de pendent, normally, upon the total quantity of lead in the tissues as a whole. In as much as this point is of great importance in the present problem, every attempt has been made to collect data from various sources, 'which would serve to demonstrate the facts in the case of the human sub ject. This is one reason for our study of a large number of subjects known to be exposed, in greatly varying degree, to lead dusts. Each subject under study was given a stoppered gallon glass jug for the collection of his urine, and a quart mason jar with a glass top for the collection of his faeces. An assistant devoted his time to sup plying these and to the delivery of them to the subject's home or place of occupation, and to the subsequent collection of them. When it was pos sible, the containers were delivered to the subject's home in order to min imize the opportunities for external contamination. Where this was im possible, for various reasons, the containers were enclosed in paper bags or.d scaled so as to avoid contamination until they should be taken home, l-'.is -.-/as especially necessary in the case of workers in plants in which 'here v,-ere lead dusts. Each subject was carefully instructed as to how to *vcid the contamination cf the contents of the container. Each one was r"quested to supply not less than two liters of urine, and not less than a 0018113 21 single large evacuation of faeces. The containers were cleaned carefully in the laboratory, and were then sealed tightly and shipped by express, or delivered by automobile to and from the laboratory. No preservatives were added to any of the samples. In some cases the samples for analysis -were not obtainable, and in a few instances, containers were destroyed in shipment. Except in the case of Group A-3 previously mentioned, these were matters of little con sequence. For the most part the subjects gave their full co-operation, and provided satisfactory material for analysis. ANALYTICAL METHODS The methods for the analysis of lead in urine and faeces in this laboratory have remained essentially the same since 1S24. It has been recognized throughout that time that, despite the general adequacy of the procedures, opportunity for slight error in the direction of low results has existed. From time to time, various steps of the method have been sub * jected to critical study. The result has been to improve the technique, and to increase the accuracy of the method at the points under study. By this means the number of completely negative analytical results has been diminished, and slightly increasing average results have been obtained. There may yet remain a few points at which the method may be refined, and there is reason for believing that very slight quantities of lead may be lost in the process of ashing the samples. However, any inaccuracies in the present methods are of small magnitude, and are of uniform occurrence. 'J-'he results are still low, if in error at all, and they do not influence the validity of conclusions based upon them in this work. All of the analytical data presented herein were obtained by - k E 0018114 22 methods detailed step by step below. Close attention has been paid to the maintenance of the utmost uniformity in the technique of carrying out the various steps. Analysis of Faeces 1. Collect in quart preserve jars (the glass top variety). 2. Dry in 500 c.c, weighed silica dishes,on a steam plate at 105 C. to constant weight. -- 3. Ash in same dish in electric muffle at a temperature never in excess of 500 C. (controlled by pyrometer). Cool. Weigh ash. 4. Moisten carefully with distilled water. Add 20 c.e. of (1:l) HN0,,, break up the ash with a stirring rod and add enough hot water to bring volume to 50 c.c. . 5. Digest on hot plate. 6. Filter into a 600 c.c. beaker. 7. Wash residue thoroughly, alternately with hot (l:l) Hi'TOg and hot water, adding washings to filtrate in (6). Dis card residue. 3. Evaporate the solution to dryness on steam plate. 9. Dissolve the residue in.(l:l) HC1 . 10. Divide the HC1 solution into 2 equal portions, the follow ing procedure being for a single portion in a 600 c.c. beaker. 11. The portion of the sample in a 600 c.c. beaker was dilut ed to approximately 300 c.c. This solution was neutral ized with 25%, NaOH, added drop by drop with constant stirring, until a slight permanent turbidity was obtain ed. The solution should be cool and should not become appreciably warm when neutralized. A few drops of a watery solution of methyl orange (l/2$) are added, a faint pink to methyl orange should persist. If it is alkaline though slightly turbid (1:2) HC1 should be added to a faint pink reaction to methyl orange. 12. Precipitate by passing H ?S gas for one hour. * Allow to stand over night. ~ 13. Filter on a 12.5 cm. vThatman ^40 Filter paper, transferr ing the settled precipitate to the paper and washing K 0018115 23 with freshly prepared water to which has been added 0.1$ of its volume of HC1, Dissolve the ppt. off the paper using hot (l:l) HC1 into the beaker in which the sulphide precipitation was made, 10 drops of concentrated HNOg being added to the HC1 to dissolve any CuS and prevent loss of lead by occlusion; wash down the sides of the beaker and gassing tube with the same acid. vTash the paper well with hot water. Digest with the acid till all the HgS has been driven off. Dilute to 300 c.c. with cold Yrater. Neutralize after adding 4 drops of a watery methyl orange solution ( %), by adding 25$ NaOH till just alkaline; then (1:2) HC1 till the faintest pink appears. Cool. Precipitate by passing HgS gas through the solution for one hour. Stand overnight. Filter as before, washing more thoroughly with acid HgS water. Wash the precipitate off the paper, using hot (l:l) HNOg, into the beaker in which the sulphide precipitation was made. Yfash well with hot water. Wash down the sides of the beaker and the inside and outside of the gassing tube, using hot (1:1) HNOg following by hot v;ater. Remove the gassing tube. Evaporate the solution to small volume and transfer to a 100 c.c. beaker. * Add 1 c.c. of HgSO^ (sp.gr. 1.84) and evaporate to fumes of H 2S04 . Cool. Take up in 30 c.c. of a mixture of 10 c.c. 95$ Ethyl al cohol (C.P.) and 20 c.c. water. Stand overnight. Filter on a 7 cm. Munktell #1-F filter paper. Washing the beaker and the paper thoroughly using a solution con taining 1 c.c. HgSO^ (sp.gr. 1.84) to 10 c.c. Ethyl alco hol (C.P.) and 20 c.c. water. Dissolve the ppt. off the paper into a 600 c.c. beaker using 10 c.c. hot 10$ ammonium acetate, followed by hot water. It is well to wash the beaker first and decant the solution through the filter. Dilute the filtrate to 300 c.c. using cold water, add 2 drops HNOg (sp. gr. 1.42). Neutralize after adding 4 drops of a solution of methyl red in 50$ alcohol, by add ing 25$ NaOH to alkalinity, then (l;2) HC1 to faint pink; then 1 c.c. of (1:2) HC1 is added in excess. Cool. !$ 24 26. Precipitate by passing HgS gas through the solution for one hour. Stand overnight. 27. Filter as before washing with extreme thoroughness. 28. Dissolve the sulphides from the paper with hot (l:l) IINO3, catching the solution and washings in the beaker in which the sulphide precipitation was made. 29. Wash the paper thoroughly with hot water, and Y/ash the sides of the beaker and the inside and outside of the gass ing tube with hot (liljHKOg followed by hot water. Remove the gassing tube. 30. Evaporate the solution to small volume, 1 to 2 c.c. and transfer it to 150 c.c. beaker. 31. Dilute to 80 c.c. with cold water. Neutralize, after add ing 4 drops of an aqueous solution of phenolphthalein (g% in 1% NaOH): using 25%0 NaOh free from iron and aluminium. The solution is made alkaline. An excess of 5 drops of 25%, NaOh are added. (When neutralized with 5% Acetic acid this will supply enough sodium acetate to repress the H* ion cone, due to the presence of slight amounts of mineral acid). 32. Acidify with 5% acetic acid till pink color just disap pears, and add 2 c.c, of 5% acetic acid in excess. 33. Bring to a boil and precipitate as chromate by adding 1 c.c. of 1%, KgCrO^ solution. 34. Place on a steam bath 1 hour and stand in a warm place at least 60 G. overnight. 35. Filter on a 7 cm. Munktell No. 1-F Filter paper. 36. Wash beaker carefully with hot water and the paper very thoroughly with hot water to remove all possible traces of soluble chromate. 37. Dissolve the ppt. from the paper, into a 250 c.c. Mohr flask containing 100 c.c. water, using 15 c.c. cold (1:2) HC1, followed by cold water. Wash the beaker and rod and decant through the paper. 38. In a 250 c.c. Mohr flask prepare a standard containing suf ficient KgCrgOy solution to be equivalent to 0.30 mgs. lead, pptd as PbCrO^. Add 100 c.c. water and 15 c.c. cold (1:2) HC1. 39. To each of the samples and the standard add 2 c.c. of a 1% solution of s. diphenyl carbazide in glacial acetic acid. KE 0018117 25 Dilute to 250 c.c. and mix thoroughly. 40. Estimate the lead in the samples by comparing the intensity of the pink color using a Duboscq colorimeter Analysis of Urine 1. Collect in gallon jugs 2. Measure the volume in c.c. and add 40 c.c.ammonia v,liter (sp.gr. 0.S0) for each liter of urine. 3. Allow to stand 24 hours. 4. Filter on a fluted pap<r, washing the jug several times with cold distilled water. 5. V/ash the jug with hot HC1 (10% by vol.) followed by hot water. Place the washings in a 250 c.c. beaker and evapor ate to dryness. 6 . Place the paper containing the precipitate in a 90 c.c. silica dish and transfer the residue in the 250 c.c. beaker, see (5). Evaporate to dryness. 7. Ash in same dish in an electric muffle at 500 C. (Con trolled by pyrometer). Cool. 8. Moisten carefully with distilled water. Add 20 c.c. of (1:1) HNO3 breaking up the ash with a stirring rod and add enough hot water to bring volume to 50 c.c. 9. Digest on hot plate. 10. Filter into a 600 cc. beaker. 11. 'Vash residue thoroughly, alternately with hot (l:l) HMO3 and hot water, adding washings to filtrate in (19). Dis card residue. 12. Evaporate the solution to dryness on steam plate. 13. Dissolve the residue in (l:l) HC1. 14. Divide the HC1 solution into 2 equal portions. From this point follow the analytical procedure for lead in fecal specimens starting at Mo. IS in the outline of the previous method. H * 0018118 3. Methods of Consideration of Data: The results of the clinical examination of each subject were gone ever while he was still available, in order to arrive at an opinion as to his condition. It was felt that the finding of a single positive result re lated to the problem at issue, would be of much greater importance than an overwhelmingly large mass of negative data. Furthermore, the generosity and courtesy of most of the subjects, in yielding themselves for observation, justified every effort on our part to give them suitable medical advice, v.-here this could be done without interference with the responsibility of plant or company physicians. Thus, subjects with early pulmonary tuberculo sis, diabetes, nephritis and heart disease, as well as certain other less important conditions, were found, and were given advice or put into the hands of physicians who would care for them. After all the examinations were completed, the data were care fully tabulated and studied. Each case was studied as a unit, in which his tory, physical examination and laboratory findings were considered. Then the groups were compared with each other in order to discover, if possible, any significant variations. This was done by statistical methods. For each group the frequency distributions of various factors of general impor tance, and of special significance to the problem of lead poisoning, were plotted. The mean values for these factors were calculated from the fre quency distributions, and comparison of these mean values was made. Where significant variations were found in the groups, attempt was made to find out the probable cause of the variation, by studying the effect of the re moval of one or more known variables, and by determinations of the presence or absence of correlation between the variants. * 001819 27 IV RESULTS AHD DISCUSSION 1. Results of General Clinical Study: ; A classification of the one hundred and sixty-four subjects ex posed to Ethyl Gasoline, on the basis of the period of continuous, present exposure, has been made in Table 4. Here it will be seen that a little more than half of the group have had two or more years of exposure, while a little less than half have had three or more years. The greater number of those who have been handling Ethyl Gasoline for three years or more, have had significant exposure to concentrated Ethyl Fluid* A further num ber of these subjects have had some significant degree of exposure to lead compounds unrelated to Ethyl Gasoline. These facts are illustrated in Table 5, in v,hich all of the test and control subjects are classified in accordance with their degree of exposure to lead other than to Ethyl Gaso line. There are three subjects in control Group A-2 (numbers 137, 147 and 172), mho have had exposure both to Etjiyl Fluid and to Ethyl Gasoline, as a result of their employment previous to this year, by a company vdiich is distributing Ethyl Gasoline. These were eliminated in the comparisons made in the following pages. Three of the medical students had driven cars in which Ethyl Gasoline was used as fuel occasionally. These were not eliminat ed for the reason that none of the findings in their cases were of any significance. These are listed in Table 5 as having had doubtful (+) lead exposure. . The factor of sources of lead absorption, other than that which might be occasioned by Ethyl Gasoline, in the case of Groups A and 3, as illustrated in Table 5, is seen to be important. The medics.l student group K 0018120 alone is practically free from this variable. Of the remaining one hundred and forty-nine control subjects only forty-five have failed to give evidence of lead exposure in their histories, ivhile forty others have had so little exposure that it may be regarded as probably insignificant. In the test group only twenty-nine give completely negative histories, and only twenty- two more give insignificant histories of exposure to lead other -than to ! Ethyl Gasoline. The proportion of negative or insignificant histories in this group is reduced somewhat below that in the control group by reason of seventy-three certainly or probably significant cases of exposure to con centrated Ethyl Fluid. A large number of persons in Group C (persons exposed to lead dusts) may be seen to have had a degree of exposure to lead, which is quite out of proportion to that shown by the other groups. This group illus trates all degrees of exposure however, and forty-one cases have had a de gree of exposure which is regarded as roughly comparable to that shown by a large number of the test and control groups. ' Table 6 gives the distribution of subjects as to age. Table 7 shows a comparison of the distributions of the various subjects according to their marital state, the number to whom living chil dren have been born and the number in whose families miscarriages have oc curred within a comparable period of time. The last three years was ar bitrarily selected as the time period, because it is only during this per iod of time that the factor of Ethyl Gasoline exposure was operative in the greater proportion of the test groups. Except -for the usual low in cidence of married persons in Group A-l, the groups are similar as to the proportion of married persons. There is nothing significant in the other compari sons. KE 0018121 29 In Tables 8 and 3 may be seen the results of the tabulation of the subjective and objective variations from the normal for all groups of subjects. Vfhen corresponding test and control groups are compared certain numerically significant differences appear. In the main the differences are not sufficient to be of clinical significance* In Table 8, the fre quency of occurrence of headache in both test and control garage mechanics is a familiar expression of carbon monoxide absorption. The occurrence of "recent loss of weight" recorded in the test filling station group and in the medical student group is due to illnesses bearing no relationship to lead and not in existence at the time of examination, or to customary sea sonal variations. Under "digestive disturbances" have been listed all periodic at tacks of gastro-intestinal discomfort or illness, abdominal cramps, peri odic or single attacks of diarrhoea, nausea, eructations, flatulency and symptoms of hyperacidity. No quantitative differentiation of these symp toms is represented in the data, nd no indication as to the time and fre quency of their occurrence is given. Except in the group exposed to lead dusts, where typical histories of previous occurrence of lead colic were given by a few subjects, no individual described symptoms in the least sug gestive of lead poisoning. Two of the tank wagon handlers of Ethyl Gaso line described symptoms characteristic of gastric or duodenal ulcer* One of these was subsequently diagnosed as such. For the most part, the symp toms referable to the gastro-intestinal tract were of such a sort as to be completely ignored in the usual examination. Under "metallic taste" were listed all examples of bad taste in the mouth which were described as sweet or sour or metallic, whether present at the time of examination or of occasional occurrence. Their evidence was 30 not significantly different in test and control groups* Furthermore, as usually described, these bear no weight in the diagnosis of lead poisoning. The numbness and tingling of the hands which is recorded as hav ing occurred in gasoline handlers, is of a different quality and signifi cance than that occurring in lead workers. The lead workers showed signs of muscular weakness and atrophy, while the gasoline handlers showed no such signs. Some degree of numbness and tingling of the hands is not infre quent in persons whose hands are frequently wet with gasoline of any kind. Usually, this appears to be the result of irritation of cutaneous nerve endings, though both peripheral nerve trunks and the central nervous sys tem as well are occasionally affected. There were no cases of the latter type in the subjects in this study* On the whole, the occurrence of symptoms of lead intoxication in the lead workers was surprisingly low. This may have been due in part to a degree of concealment. Frcbably a more important cause was to be found in the fact that both plants in vhich observations were made had been in oper ation for only a short time before these studies began, there having been a large diminution in their activities during a slack season of approximately two months. A critical study of Table 9, discloses even less material of sig nificance than can be found in a study of symptoms (Table 8), except in Group C. Here ten subjects show a definite pallor, (a large number were negroes in whom this factor was difficult to observe), while twenty show sensory disturbances, several of which were of a type presumably related to lead absorption. There were three examples of weakness of extensor muscles in this group, definitely related to lead. One of these was an old case of drop wrist. There was only one gingival lead line to' be 31 found in the group. In general their condition was remarkably good, con sidering the degree of exposure experienced by some of them The occurrence of hyperacidity of the urine was significantly higher in this group than in any other in spite of their lower age incidence and a low incidence of acute colds. However, the high incidence of urinary hyperacidity in test filling station attendants, and both test and control tank wagon handlers of gasoline correlates roughly with the incidence of acute colds, as evi denced by temperature elevations. It is in further correspondence with their higher age incidence and the associated occurrence of cardio-vascular abnormalities. The frequency of occurrence of urinary hyperacidity in both the test and control garage mechanics may be due to a degree of carbon monoxide absorption. The one lead line seen in test group B-2 (Garage Mechanics) occurr ed in a man with a significant history of exposure to lead* His total ex posure to Ethyl Gasoline took place over a period of 1.3 years. There is scant reason for relating the finding to Ethyl Gasoline. The study of symptoms and physical signs in their relation to any type of illness by the method represented in the preparation of Tables 8 and 9, is obviously unsatisfactory. It has been done in this case with a full appreciation of its inadequacy, for the purpose of representing the groups as individual entities, and to set forth some of the data in a form in which they may be seen. It is of much greater value to consider the manner in which symptoms and signs group themselves in individual subjects. By this means it has been possible in most cases to arrive at a satisfactory ex planation of the nature of the condition which has given rise to a number of related abnormalities. In each group of subjects, however, there are occasional individuals who show indefinite or slight variations from the . K 0018124 32 normal for which there is no apparent explanation. Special attention has been devoted to the study of these cases, vdth the following results: (l) They occur in approximately equal proportions in the control and test groups. (2) The severity of symptoms and the degree of physical abnor mality are not significantly variable in control and test groups. (3) There is no relationship between duration or intensity of exposure to Ethyl Gaso line, and the occurrence of abnormalities. (4) There is no apparent asso ciation of either symptoms or signs with the quantity of lead excretion in the urine or faeces. These facts exclude the likelihood that Ethyl Gaso line exposure is a causal factor in the occurrence of abnormalities in the test groups. In the entire group of persons exposed to Ethyl Gasoline there is no single case which combines symptoms, physical signs, and laboratory findings in such a m y as to give a suggestive clinical picture of intoxi cation due to lead absorption. This is true, likewise, in the case of the control subjects, with the exception of those who have been exposed to lead dusts. In the latter group there are several cases who have described characteristic attacks of lead intoxication* In a number of cases these attacks have recurred in slight or moderate severity, from time to time, and have been relieved by temporary'freedom from exposure and the use of saline cathartics. A large proportion of such subjects demonstrated physi cal evidences of the occurrence of intoxication, in the form of pallor, tremors, extensor weakness of one or both wrists, relatively large numbers of stippled erythrocytes, and relatively high lead excretion* Several, on the contrary, showed no evidence of continuing or residual effects, at the time of their examination. There is one subject in the test group, whose case merits special 33 consideration, for the reason that there is justification for a suspicion that lead absorption has been a factor in his condition* This man, sub ject No. 544, is now a tank wagon handler of Ethyl Gasoline. He is a negro, thirty-five years of age, and married. Two children have been born in the past three years, and no miscarriages have occurred. There are no suggestive physical signs of lead intoxication, nor is there any stippling, anemia or excretory evidence of unusual lead absorption. The history sup plies the only material of note. During a period of approximately one year, prior to 1926, this subject was exposed to tetraethyl lead, in mix ing Ethyl Fluid with gasoline in tank wagon lots, by a method now obsolete. He had almost daily opportunity to inhale and to absorb through his skin significant quantities of tetraethyl lead. There is not a strict coinci dence in the onset of symptoms and the period of exposure, but due allow ance must be made for the factor of memory. The subject stated that he has not been in good health for a period which he estimated at five years, During the early part of this period he lost weight, which he has not re gained. He has suffered from sleeplessness, and is frequently disturbed by dreams when asleep. He has headaches frequently, fatigues easily and often has joint and muscle pains. In addition to these things he complains of the sensation of "ants crawling over him." These are not symptoms of sufficient specificity to be diagnostic, but the character of the nervous system symptoms is suggestive when the selective localization of tetraethyl lead in the nervous system (when absorbed in comparatively large amounts), is considered. A diagnosis cannot be made in this case with any assurance, for meningeal or cerebral irritation from any cause may be productive of such symptoms. In any event, this case is not related to the present rroblem of the hazards of Ethyl Gasoline as now handled and marketed. It 0018126 merely serves to illustrate the complication which must be dealt with in the consideration of such tests subjects as have had significant exposure to concentrated Ethyl Fluid, as well as to Ethyl Gasoline. 2. Results of Statistical Study, The frequency distributions of age, systolic blood pressure, pulse pressure, haemoglobin determinations, number of stippled erythrocytes per fifty fields, lead in faeces both in milligrams per one hundred grams dry weight, and in milligrams per gram of ash, and lead in urine in milli grams per liter, have been worked out for the various groups in their en tirety. Groups A-2 and A-3 have been combined in these teb les for two rea sons. They are both made up of gasoline handlers who have no appreciable lead exposure as a primary result of their occupations. They are therefore suitable for combination as .a control group showing the influence of ordi nary gasoline as compared with Ethyl Gasoline. Further, the data on lead excretion are not available in the case of A-3, for reasons previously ex plained, and this group is of little'value, therefore, considered alone. It is vrorth 'while only in as much as it adds to the data on the symptomatic or physical effects of handling gasoline. It is .to be remembered that the data on lead excretion in this combined group are derived from the study of A-2 only. The test subjects comparable to these found in Groups B-l and 3-3 have been handled both separately, in order to observe any differences which might be due to their varying exposure to Ethyl Gasoline, and in combination, in order to make comparison with the combined Groups A-2 and A-3. In calculating the mean values for lead excretion in both urine ;d faeces, a few extremely high results in the A and B groups have been 0018127 35 ignored, although they are recorded in the distribution tables. These re sults are either unreliable because of the extremely small size of the original sample submitted, or they are so abnormal in their occurrence as to be under the suspicion of having resulted from contamination of the sample in the process of collection. They occur in approximately equal numbers in the A and B groups, so that their elimination has no appreciable effect upon the results, except to decrease the probable error of the mean values. A comparison of the mean values of the above factors for the various groups is made in Table 10. The mean age in Groups A-l, A-4 and C is significantly lower than that in the other groups. The mean systolic blood pressure of Groups A-2 + A-3, B1 and B3 is significantly high. This variation is associated with the age differences in the various groups. The mean pulse pressure of Groups A-2 A-3 and B3 correspond to their high systolic pressure, thus indicating the probability of the occurrence of vascular disease in a significant number of subjects in these groups, an interpretation borne out by the clinical records in other ways It is of significance that the pulse pressure in Group C is significantly high des pite the lack of high systolic pressure. The lowering of the mean dias tolic pressure is sufficiently familiar in lead intoxication to require no comment. The heightening of the mean systolic pressure in Group B-l \vithout a corresponding heightening of systolic pressure in Group B-l without a corresponding heightening of the mean pulse pressure, does not yield itself to other than hypothetical interpretation. The differences in mean haemoglobin readings are not significant, nor is there any correlation of haemoglobin reading and age. In the en tire group of subjects there are only a few haemoglobin readings low enough to be of clinical significance. 36 The results of the comparison of the mean values of factors more specifically related to lead absorption are noteworthy. It is especially important that Group C differentiates itself from all the other groups in all three of these items. The differentiation is most striking in the matter of stippling of erythrocytes. It is almost as great in the matter of lead excretion in the faeces, and less sharp but significant in the case of urinary excretion of lead. This is illustrated graphically in Chart No. 1. It is a matter of interest that the medical student group also differentiates itself from the test groups and the other control groups as well. The differentiation is slight and not significantly great in all cases. However, in every case the mean values of stippling, lead in urine and lead in faeces is lower than in the other groups. The chief importance of this in the present study lies in the fact that it indicates the probable accuracy of the history taken with regard to the signifi cance of previous lead exposure on the part of test and control groups. Cf. Table 11. In order to compare control subjects with test subjects in the absence of the variable of lead exposure other than to Ethyl Gasoline, all persons who gave significant histories of other lead exposure were elimin ated. Frequency distributions on haemoglobin, stippling, lead in faeces and lead in urine were made including only such subjects as gave completely negative or probably insignificant histories. The garage mechanics in both test and control groups gave very little history of exposure to lead other than that occasioned by their occupation, but because of that fac tor, they were regarded as unsuitable for inclusion in the present compar ison. Table 11 shows the mean values of the above items, taken from a KE- 0018129 37 study of forty-seven handlers of Ethyl Gasodine, and eighty-nine handlers of ordinary gasoline. The mean value of the faecal lead excretion of Group 51 * B3 has been obtained after the elimination of two very high results. These results were 1.36 mg. and 1.50 mg. per gram of ash. The actual quantities of lead found in these two samples were 5.10 mg. and 4.20 mg. Such amounts of lead are not found in faeces except^ in the case of persons who are exposed to large quantities of lead dust. Persons ex creting these quantities of lead in their faeces usually show a corre spondingly large urinary excretion, and evidences of lead absorption in their blood. These two individuals, Subjects Nos. 317 and 318, showed very slight quantities of lead in their urine, 0.01 mg. and 0,03 mg. re spectively, and no clinical evidences of lead absorption. The lead al most certainly gained entrance into their specimens as the result of ex ternal contamination.. With these two eliminated the difference between the mean of test and control group is negligible. A comparison of the mean values for lead excretion in the urine and faeces, with the corresponding means for the entire groups as represented in Table 10, demonstrates the significance of the other sources of lead exposure. Thus, with other lead exposures eliminated, these groups are now indistinguishable, not only from each other, but also from Group A-l, not only as to lead excretion but also as to stippling. The subjects in Groups B-2 and B-3, selected for study because of the absence of histories of exposure to lead compounds other than that in Ethyl Gasoline have had a wide variation in the periods of their expos ure. Assuming that stippling of erythrocytes and the excretion of lead in the urine and faeces vary with the magnitude of absorption of lead com pounds, there should be some degree of correlation between length of expos - K E 0018130 ure to Ethyl G-asoline and the quantity of stippling and lead excretion, provided exposure to Ethyl Gasoline brings about a significant degree of exposure to lead. Investigation has been made of the validity of this original assumption, and of the occurrence or non-occurrence of the above correlation. Table 12 shows a comparison of the "correlation constants" of stippling, lead in faeces, and lead in urine in relation to periods of exposure to Ethyl Gasoline, together with similar constants obtained from the study of a group made up of Group C, plus a number of cases selected from Group A-2 and A-3, whose histories are sufficiently definite as to type and degree of their lead exposure. This entire group has been care fully studied in order to classify lead exposure into definite magnitudes, based upon the intensity, duration, and time of occurrence (i.e., 'whether present or past or how far in past) of exposure to lead compounds* Despite the errors which are unavoidable in such a classification and despite the inadequacy of the number of subjects 'which represent certain magnitudes of exposure, there is a very, definite relationship between the degree of exposure to lead and the magnitude of stippling and lead excre tion in the faeces. On the other hand, there is no relationship between the period of exposure to Ethyl Gasoline and the magnitude of stippling, lead excretion in faeces, or lead excretion in urine. The investigation for this year has included a number of subjects on whom observations have been made in the past. It was regarded as worth while to compare the findings on this group in 1926-2 7 with those of the pre.sent year. Ac cordingly the data on these cases is included in the tables of individual findings, of the present study. In addition, the frequency distributions of haemoglobin readings, stippling of the erythrocytes per 50 fields, and the unit lead content of the urine and faeces, were studied for the two 39 years. Comparison of the histories and clinical findings on identical subjects for the two years showed a striking uniformity in the information obtained* There was no case in which slight variations from the normal had become significantly intensified by the elapse of a year. Table 13 shows a comparison of the mean values of the more im portant factors studied. There is a significant difference between the corresponding means for the two years in every item except that of stippling. This latter item is the one in which there was the greatest uniformity in the methods of study for the two years and it probably represents the facts more reliably than do the other comparisons. The method for studying stippling in the subjects was as nearly identical for the two years as can be accomplished by the use of the same kind of stain, the same technique of staining, and the same methods of examinations in the hands of the same examiner, ihe difference in the haemoglobin means is sufficiently small to be of no clinical significance, and is within the limits of the varia tion of two Dare instruments. The comparatively large differences in the mean lead content of the faeces and urine for the two years would seem to indicate that this group of individuals, as a whole, is excreting more lead at the time these samples were obtained than they were a year ago. For reasons pointed out in preceding paragraphs, this is not a valid conclusion* These differences are rather an expression of the increased sensitivity of the methods of analysis for lead in urine and faeces, brought about by a critical study of these methods within the past year. A study of the data shows a strik ing variation in the occurrence of negative or very low results in the data of 1926-27 as compared to those of 1927-28. It is at this point that increased analytical accuracy should show itself most strikingly. The relative importance of slightly low results when dealing with larger total quantities of lead, is obviously less. Thus when the mean values of lead excretion in faeces and urine are calculated after the elimination of all results lower than 0.029 milligrams, the differences in these factors for the two years are reduced to insignificance. Therefore, there is no evi dence that the additional year of exposure has influenced the lead absorp tion of this group of subjects. Tables 14 to 21 inclusive show the distribution of subjects in all groups according to the occurrence of stippled red cells, and lead in urine and faeces. These tables set forth the data from which the means have been calculated for the various groups. Tables 22 and 23 show the data from which the correlation con stants of Table 12 have been calculated. The original data from which the other tables have been prepared is tc be found in the final tables of individual findings. 0018133 V CONCLUSIONS The detailed study of one hundred and sixty-four persons who have experienced industrial exposure to the possible lead hazards associat ed with the distribution and use of Ethyl Gasoline, fails to show any evi dence for the existence of such hazards. The exposure of sixty-nine of these individuals has continued over a period of from three to five years, and practically all persons in the United States, who have had the most intense and most prolonged exposure, are included in the group studied. . It would be expected that there would be some individuals in a group of this size who would be unusually susceptible to 3.ead compounds, but there is no evidence of the occurrence of an isolated case of lead intoxication in the group. The industrial exposures herein considered are much more continuous and intense than those to which ordinary drivers of motor cars, or the general public, are subjected. The relative importance of the time element in lead poisoning is undoubtedly great. For this reason, evidence as to whether lead is being absorbed, as a result of exposure to Ethyl Gasoline, must be regarded as more significant than the absence of the occurrence of lead poisoning, up to the present. Our comparisons of groups of individuals with varying lead exposure, support the belief that the amount of stippling of the erythro cytes, and quantity of excretion of lead may be regarded as criteria of the magnitude of lead absorption. The data of this study give no evidence that persons who are exposed to Ethyl Gasoline have absorbed appreciable quantities of lead, as a result of such exposure. April 13, 1928. K 0018134 42 VI TABLES K 0018135 3 TABLE 1 Group Sub-Group Control ]_ 2 3 1 Description of Group Not Exposed to Ethyl Gasoline Medical Students Filling Station Attendants Tank '.Tagon and Bulk Handlers Garage Mechanics (Studied 1926) p Test T OU* 3 Exposed to Ethyl Gasoline Filling Station Attendants Garage Mechanics Tank Tiagon and Bulk Handlers C Control Exposed to Lead Dusts in Lead Trades limber of Subjects 220 71 72 42 35 164 77 35 52 122 HE 0018136 TABLE 2 PERIOD OF DISTRIBUTION OF ETHYL GASOLINE AND TETRAETHYL LEAD CONTENT IN VARIOUS AMERICAN CITIES. Locality Intro duction Interval of Discontinuance Present Period of Continuous Distribu. Present Range of Tetraethyl Lead Content By Volume, 1 Part in Dayton, Ohio * Feb. 1923 None 5 years 5400 to 2100 Cincinnati, Ohio * Apr. 1923 None 4.5 years 5400 to 2100 7-fneeling V.r. V a . Summer 1923 May 1925-Summer 1926 1.5 years 5400 to 3150 Chicago, 111. * Autumn 1923 May 1925-June 1926 1.5 years 2100 to 1510 Detroit, Mich. * Autumn 1923 May 1925-Jvme 1926 1,5 years 2100 to 1510 Pittsburgh, pa. Autumn 1923 May 1925-Aug. 1326 1.5 years 2520 to 1890 St. Louis, Mo. Spring 1924 May 1925-Summer 1926 1.5 years 2520 to 1890 Kansas City, Mo. Spring 1924 May 1925-Summer 1926 1.5 years 2520 to 1890 Baltimore, Md. Spring 1*24 May 1925-Summer 1926 1.5 years 5400 to 2230 'Mashington, D .C . Spring 1924 May 1925-Summer 1926 1.5 years 5400 to 2230 San Antonio, Tex. Spring 1S24 May 1925-Summer 1926 1.5 years 2230 to 1890 Sa-.'annah, Ga. * Autumn 1924 None 3,5 years 2520 to 18S0 Atlanta, Ga, * Autumn 1924 None 3.5 years 2520 to 1890 Cleveland, Ohio Summer 1926 None 1.5 years 5400 to 252C Philadelphia, Pa, Summer 1926 None 1.5 years 3780 to 2520 Boston, Mass. Summer 1926 None 1.5 years 4730 to 2230 San Francisco,Cal. Summer 1927 None 0.5 years 15140 to 5400 Los Angeles, Cal. Summer 1927 None 0 5 years 5400 and over Spokane, '.Cash. Summer 1927 None 0.5 years 3780 to 2100 * Subjects selected for study. TABLE 3. DISTRIBUTION OF SUBJECTS ACCORDING TO LOCALITY Locality Type of Subject Cincinnati, Ohio Dayton, Ohio Columbus, Ohio Chicago, 111. Detroit, Mich. Atlanta, Birmingham and Savannah, Ga. New York City Viashington, D. C. Medical Students Filling Station Attendants Filling Station Attendants Garage Mechanics Tank Yiagon and Bulk Handlers Filling Station Attendants Filling Station Attendants Garage Mechanics Tank Yiagon and Bulk Handlers Garage Mechanics Tank Yiagon and Bulk Handlers Filling Station Attendants Garage Mechanics Tank Yiagon and Bulk Handlers Tank Yiagon and Bulk Handlers Garage Mechanics (1926) TOTALS Exposed to Ethyl Gasoline B Not Exposed to Ethyl Gasoline A None 24 24 10 8 None 15 12 12 11 17 14 U0/ 15 None None 71 None 36 None None 36 None None None None None None None N one 42 35 164 220 46 TABLE NO. 4 DISTRIBUTION OF SUBJECTS ACCORDING TO PERIOD OF EXPOSURE TO ETHYL GASOLINE. Group B-l Filling Station Attendants 3-2 Garage Mechanics 3-3 Tank YJagon and Bulk Handlers I oo - Time in Years to Nearest Decimal 0.5 1.0 1.5- 2,0 2.5- 3.0 3.5 ALL 0.9 1.4 1.9 2,4 2.9 3,4 4.04- YEARS F'ERCENTAGE DISTRIBUTION 0 1 4 21 12 0 11 11 26 34 3 26 33 088 100 100 3 8 6 33 9 4 11 21 100 DISTRIBUTION OF PERSONS 3-1 rilling Station Atte ndants 0 1 3 16 9 2 20 26 3-2 Garage Mechanics 0 4 4 9 12 0 3 3 3-3 Tank Yagon and Bulk Handlers 4 4 3 17 5 2 6 11 77 35 ::52 47 table 5 DISTRIBUTION OF SUBJECTS ACCORDING TO EXPOSURE TO LEAD OTHER THAN ETHYL GASOLINE. <D oc S *H 44 .9 O P V H $4 P 4-> d0) CO 0 u P O 4-5d 4- Jh 01 P H Cl o 4041HCOrO?HH d P-4 U cfl p nd 0 P 4-3 eu: 05 A C1D- U v0 <15 H o /U* .1i pu O 44>40-53 a0 Ud 0> 03 u o od *r4 H rH u 03 d O rH P COP P f=- d eu. od rH O U P 4-3 01 d P d to oCl ,H ou p 01 03 P 4-3 03 03 C-i 03 d 03 r4 p> ou>CaO> +P0d33 <13 d <D 03 03 O PP to d O P 4-> 01 Cij P u o 03 C4 Ci > CD 00 u > M 0 d o 4-3 0d 01 03 *4 P W) os tA >> fH 40-3 c3 d 4-3 0 f-i 0d 0 t do 0 >0 0 C4 rH o*4 COP P 0 t * "9 4 4 4 " 44444 444*i4H PERCENTAGE DISTRIBUTION A-l Students 64.8 29.6 5.6 0 0 0 0 A-2 Fill.Sta. Att. 38.9 36.1 20.8 4.2 0 0 0 5-1 Fill.Sta.Att. 22.1 18.2 20.8 38,9 0 0 0 A-4' Garage Mech. 0 8.6 77.2 14.2 0 0 0 3-2 Garage Mech. 0 11.4 77.2 11.4 0 0 0 A-3 Tank '.'.'agon & 59.5 23,8 14.3 2.4 0 0 0 Bulk Handlers 7u> _ \7j ditto 23.1 7.7 17V3 44.2 7.7 0 Ur persons Exposed 0 to Lead Dusts 0 0 4.1 32.0 33.6 8.2 7.4 B Persons Exposed To Ethyl Gas. 17.7 13.4 31.7 34.8 2.4 0 0 t Cl Persons Not Exp. to Ethyl Gas. 45.0 27.3 23.6 -4.1 0 0 0 0 0 0 0 0 0 0 9.0 0 0 0 100 0 100 0 100 0 100 0 100 0 100 0 100 5.7 100 0 100 0 100 DISTRIBUTION OF PERSONS A-l Students 46 21 4 0 0 0 0 A-2 Fill.Sta.Att, 28 26 15 3 0 0 0 B-l Fill.Sta.Att. 17 14 16 30 0 0 0 A-4 Garage Mech. 3-2 Garage Mech. 0 3 27 5 0 0 0 0 4 27 /t 0 0 0 A-3 Tank '"agon & Bulk Handlers 25 10 6 1 0 0 0 3-3 ditto 12 4 9 23 4 0 0 C Persons Exposed to Lead Dusts 0 0 5 39 41 10 9 3 Persons Exposed to Ethyl Gas. 29 22 52 57 4 0 - 0 A persons Not Exp. to Ethyl Gas. 99 60 52 9 0 0 0 0 0 0 0 0 0 0 11 0 0 0 71 0 72 0 77 0 35 0 35 0 42 0 52 7 122 0 164 0 220 48 TABLE 6 DISTRIBUTION OF SUBJECTS AS TO AGE Age in Years - ALL 15- 20- 25- SO 35- 40- 45- 50- 55- 60- 65- 70- YEARS 19 24 29 IL. 39 44 49 54 59 64 69 74 PERCENTAGE DISTRIBUTION A-l Medical Stud. 15 72 13 100 A-2 & A-3 Fill.Sta. Att. & Bulk Gas.Handlers 1 16 20 14 10 11 9 9 4 4 3 100 A-4 Garage Mech. 'control) 6 6 34 34 6 11 3 100 B-l Fill.Sta.Att. 8 26 12 9 14 4 5 10 5 4 3 100 3-2 Garage Mech. (test) 14 14 26 17 14 11 3 100 5-3 Bulk Gas.Handl. 8 19 15 21 10 13 6 4 4 100 C Persons Exposed to Lead Dust 7 25 23 11 12 7 7 s 1 1 1 100 DISTRIBUTION OF PERSONS A-l Medical Stud. 11 51 9 71 A-2 & A-3-Fill.Sta. Att. & Bulk Gas.Handlers 1 18 23 16 11 13 10 10 5 4 3 114 A-4 Garage Mech. (control) 2 2 12 12 2 4 1 35 B-l Fill.Sta.Att. 6 20 9 7 11 3 4 8 4 3 2 77 B-2 Garage Mech. (test) 5 596 54 1 35 3-3 Bulk Gas.Handl, 4 10 8 11 5 7 3 2 2 52 C Persons Exposed to Lead Dust 9 30 28 14 15 8 8 7 1 1 1 122 TABLE 7 DISTRIBUTION OF SUBJECTS ACCORDING TO MARITAL STATE, AND OCCURRENCE OF BIRTH AND MISCARRIAGES DURING LAST THREE YEARS PERIOD. Persons Married Persons to whom Children Born Persons in whose Family Miscarriage has Occurred GROUP' TOTAL NO. A-l Medical Students A-2 Filling Station Attendants B-l ditto A-4 Garage Mechanics B-2 ditto A-3 Tank Wagon and Bulk Handlers B-3 ditto C Persons Exposed to Lead Dusts B Persons Exposed to Ethyl Gas. 7 Persons Not Exposed to Ethyl Gas. 5.6 75.0 81.8 62.9 82.9 76.3 88.5 55.6 84.1 50.9 PERCENTAGE DISTRIBUTION .\ 00 8.3 2.8 11.7 1.3 17.1 2.9 22.9 5.7 33.3 2.4 19.2 0 18.0 3,3 16.5 1.8 16.4 1.8 A-l Medical Students 4 A-2 Filling Station Attendants 54 B-l ditto 63 A-4 Garage Mechanics 22 B-2 ditto 29 A-3 Tank Wagon and Bulk Handlers 32 B-3 ditto 46 C Persons Exposed to Lead Dusts 80 B Persons Exposed to Ethyl Gas. 138 A Persons Not Exposed to Ethyl Gas. 112 DISTRIBUTION OF PERSONS 00 62 91 61 82 14 1 10 0 22 4 27 3 36 4 71 72 77 35 35 42 52 122 164 220 0018142 50 TABLE 8 DISTRIBUTION OP SUBJECTS ACCORDING TO SUBJECTIVE ABNORMALITIES. d CD rO Jh P< 4- Q) WO PH rH CO ..-- I H O -P H W -P (3 rt oo p< -- ... CO O 5 H 4-a a> fes <D O 0) o Pi I ^ 33 o -u S3 rH CD Cfl O a> S.h O rH O flS Ph ... ap> 5o . *H 4-3 c6 0) >o , rH o rH 0) d r-4 -p n3 d CO d -p d a> 4 W si -- ! '-- 1 -P CO H *H od a> co rH & aB co co Sb ok 1.1 III CO <oD <D >d rH rO +> fH W 0> -p CO PH PH d rH K CD O ' -- to a) CO CO oCQ *d W d <D c3 W rH d 3 <oH -oP $3 &H -- " PERCENTAGE DISTRIBUTION A-l Medical Students 4.2 36.6 9.9 2.8 12.7 21.2 pill. Sta. Att. B-l Exposed A-2 Not Exposed 3.9 24.7 7.8 7.8 5.2 24.7 2.9 27.6 1.4 4.3 17.4 24.6 1.4 1.4 2.8 1.4 Nil / 2.6 7.8 16.9 5.2 1.3 10.1 2.9 11.6 7.3 7.3 Garage Mechanics 3-2 Exposed A-4 Not Exposed 2.8 22.6 Nil 5.7 25.8 14.3 2,8 Nil 57.2 2.8 14.3 51.5 2.8 Nil 22.7 8.6 Nil 22.8 - 5.7 11.4 - Tank Wagon A Bulk 3-3 Exposed 3.8 23.2 3.8 11.6 17.3 21.2 A-3 Not Exposed 13.5 5.8 11.6 9.6 3.8 C Persons Exposed to Lead Dusts 2.5 9.8 0.8 0.8 5.7 13.1 3,3 4.1 7.4 3.3 2,5 DISTRIBUTION OF PERSONS A-l Medical Students 3 26 7 2 9 15 4? 1 1 2 Fill. Sta. Att. 3-1 Exposed 3 19 6 6 4 19 1? 2 6 13 A-2 Not Exposed C 19 1 3 12 17 4? 7 2 8 Garage Mechanics B-2 Exposed A-4 Not Exposed 1 2 8 None 1 None 13 .3? 1 None .9 9 5 1 5 18 None 8 - 2 Tank Wagon & Bulk 3-3 Exposed A-3 Not Exposed 2 2 12 4 2 6 9 11 7? 7 3 6 2 None' 5 7 7? None None 10 C Persons Exposed to Lead Dusts 3 12 1 1 7 16 22? 4 5 9 1 None 71 4 1 77 5 5 69 3 35 4 - 35 5 2 52 2 2 42 4 3 122  Undernu1 trition Tachycardiai 100) [Bradycardia (60) Temp.Elevation(96.8) Terap .Depre s sion (97.6) Pallor jA.denopathy Tremor Nose-t-ThroatLesions Pyorrhoea Lead Line Cardiac Lesions Pulmonary Lesions Abdominal Lesions Pelvic [Lesions Table 9 DISTRIBUTION OF SUBJECTS ACCORDING TO OBJECTIVE ABNORMALITIES w CO <D b H i t H t U H r-i W M t <D H t aX < O K 05 t *H O fH r4 4-> t fi Z uj A-l Med. Stu, 9.9 7.0 Fill.Sta.Att B-l Exposed 16.9 19.5 A-2 Not Expos. 18.9 14.5 Garage Mech. B-2 Exposed 8.6 2.8 A-4 Not Expos. Nil 17.3 Tnk.Wag&Bulk B-3 Exposed 15.4 11.5 A-3 Not Expos. Nil 4.8 C Persons Exp. to Lead Dusts 4.1 8.2 5.6 7.0 4.2 2.6 37.6 2.6 1.5 18.9 Nil 8.6 5.7 Nil Nil 25.8 17.3 3.8 36.6 Nil 4.8 33.4 2.4 5.6 22.2 11.5 - PERCENTAGE DISTRIBUTION 1.4 29.6 Nil 2.8 52.1 2.8 Nil 1.4 1.4 2,6 24.7 1.3 14.3 52.0 57.2 Nil 10.4 6.5 4.4 42.0 2.9 13.0 42.0 59.5 Nil 11.6 13.0 5.7 37.1 Nil 5.7 45.2 68..6 2.8 Nil Nil Nil 40.0 11.4 8.6 40.0 68.6 Nil Nil Nil 3.8 34.6 5.8 7.7 44.3 67.3 Nil 7.7 Nil Nil 40.5 Nil 9.5 33.4 71.4 Nil Nil 4.8 8.2 49.2 3.2 18.0 27.0 53.3 0.8 6.4 1.6 2.8 18.3 Nil 3.9 15.6 6.5 8.7 13.0 2.9 1 2.8 17.3 8.6 Nil 14.3 8.6 3.8 17.3 3.8 7.1 11.9 2.4 0.8 12.3 13.1 1 A-l Med. Stu. 7 Fill.Sta.Att B-l Exposed 13 A-2 Not Exoos. 13 Garage Mech. B-2 Exposed 3 A-4 Not Expos. Nne TnkWag& Bulk B-3 Exposed 8 A-3 Not Expos. None C Persons Exp; to Lead Dusts 5 54 15 2 10 1 13 6 None 62 22 10 7 53 1 29 2 13 None 2 3 2 None 2 9 6 None 19 None 2 14 1 None 27 14 10 - DISTRIBUTION OF PERSONS 21 None 2 - 37 2 None 1 1 2 13 None 19 1 11 40 44 None 8 5 3 12 5 29 2 9 29 41 None 8 o r>o g 2 13 None 2 16 24 1 None None 1 63 14 4 3 14 24 None None None None 5 3 18 3 4 23 35 None 4 None 2 9 2 17 None 4 14 30 None None 2 3 5 1 60 4 22 33 65 1 8 2 1 15 16 TABLE 10 COMPARISON OF MEAN VALUES OF AGE, BLOOD PRESSURE, HAEMOGLOBIN STIPFLING OF ERYTHROCYTES, AND EXCRETION OF LEAD IN FAECES AND URINE 0> A-l Medical Students 22 A-2 & -1-3 Filling Sta. Att. and Bulk Gas Handlers 38 B-l Filling Sta. Att. 40 B-3 Bulk Gas. Handlers 38 B-l & B-3 - A-4 Garage Mechanics (Control) 31 B-2 Garage Mechanics (Test) 35 C Persons Exposed to Lead Dust 32 o *r*4 u pH PO TO CO o m ,roH 0to co u Pi 126 CO 3 gms (!) -P CO ^5 5oou a jyj0W Sop*,cinco S3 COo p,P4 I0 O *H O r-l & *H tf O P + *j ^ O 2 rH CO O pH CS <D ci hWO CO 3 a H CO ,w d o' d o> to <u d up 1-4 <w & P H H fH H CO 2 CO Pk ofe \ 49 90 1,0 1.0 .08 CO o 71 138 55 86 1 7 1.3 ,10 .13 114 137 51 8 8 2,3 2.0 .14 .11 77 136 54 85 2.1 1 . 2 .09 .15 52 -- 87 2,2 1.7 .12 .13 129 130 5a 88 1.4 1.5 ,13 .11 35 133 50 86 2.0 1,7 .14 .13 35 132 55 85 17.0 10.3 .73 .21 122 53 54 TABLE 11 MEAN VALUES AND PROBABLE ERRORS, SHOWING BY COMPARISON TBE SIGNIFICANCE OF DIFFERENCES IN BLOOD AND CHEMICAL FINDINGS FOR CONTROL AND TEST FILLING STATION ATTENDANTS AND BULK HANDLERS OF GASOLINE, EXCEPTING THOSE "WHO HAVE HAD OTHER LEAN EXPOSURE. Stippled erythro cytes Lead in Lead in faeces ' urine No. Mgms./gm.ash Mgms ./liter Persons Control (AN*A3) Test (B1+B3) 1.35 * .12 .074 2 *007 .096 2 *009 1,77 jt .18 .087 2 *009 .085 2 *007 84 47 Differences .42 .22 .012 .011 .010 .012 55 TABLE 12 COMPARISON OF CORRELATIONS OF EXPOSURES TO ETHYL GASOLINE AND LEAD DUSTS, IN BLOOD AND CHEMICAL FINDINGS. Stippling Lead Content of faeoes Lead Content of urine Exposed to Ethyl gas alone Exposed to significant lead dusts alone -.08 t ..10 - .13 * .11 - .11 * .10 *,27 4 .05 .37 * .07 * ,04 .07 H 0018148 56 Year TABLE 13 COMPARISON OF MEAN VALUES OP HAEMOGLOBIN, STIPPLING AND EX CRETION OF LEAD FOR THE YEARS 1926-27 AND 1927-28, OF A GROUP OF 65 FILLING STATION ATTENDANTS, GARAGE MECHANICS, AND TANK WAGON HANDLERS OF ETHYL GASOLINE, ON WHOM OBSERVA TIONS HAVE BEEN REPEATED. Haemo globin Stippling 50 F. Lead in Faeces-Mgs/Gm Ash Excluding 0 - 0.029 All .Results results Lead in Urine - Mgs/Liter Excluding 0 - 0.029 All Results results 1926-27 85.3 0.7 2.39 0,30 0.63 0.005 0.094 0.006 0.075 0.008 0.115 0,011 1927-28 89.0 0.7 1.74 0.15 0.116 0.009 0.126 0.009 0.134 0.012 0.143 0.013 Differ ences 3.6 0.9 0.65 0.33 0.053 0.010 0.031 0.011 0.058 0.015 0.028 0.017 0018149 TABLE 14 PERCENTAGE DISTRIBUTION OF PERSONS /iS TO STIPPLED RED CELLS PER 50 FIELDS Total Under 1 1 2 3 4 5 6 7 8 9 10 - 24 25 - 49 50 - 74 75 and over Medical Student ATM! Fil.sta. Garage Att.and Meehan- Bulk Gas ics Handlers (Control) A-2 & A-3 A-4 Filling Station Attend. B-l Garage Meehan- ics (test) B-2 Bulk Gas Hand lers B-3 100 100 100 100 100 100 82 63 , 63 48 46 48 7 18 17 19 20 21 7 6 6 10 \17 4 1 4 6 11 3 6 11 1 3 13 26132 335 3 2 2 1 2 13 12 13 2 1 Persons exposed to lead dusts C 100 13 8 9 7 2 8 7 3 2 24 7 3 7 0018150 58 TABLE 15 DISTRIBUTION OF FERSONS AS TO STIPPLED RED CELLS PER 50 FIELDS. Medical Student A-l Fil.Sta. Garage Att.and Mechan BulkGas ics Handlrs (Control) A-2 & A-3 A-4 Filling Station Attend. B-l Garage Meehan- ics (Test) B-2 Bulk _ Gas Hand lers B-3 Persons exposed to lead dusts C Total Under 1 1 2 3 4 5 6 7 8 9 10 - 24 25 - 49 50 - 74 75 and over 71 114 35 73 35 \ 58 72 22 35 . 16 5 20 6 .14 7 5 727 6 14281 11 11 2211 314 1 21 11 11 12 * 1 52 122 25 16 11 10 2 11 38 73 1 10 19 1 4 2 1 29 8 4 8 KE" 0018151 TABLE 16 PERCENTAGE DISTRIBUTION OF PERSONS ACCORDING TO LEAD MGS./lOO GM. DRY FAECES. Medical Student A-l Fil.Sta. Garage Att.and Meehan- BulkGas ics Bandirs (Control) A-2 & A-3 A-4 Filling Station Attend. B-l Garage Meehan- ics (Test) B-2* Total 100 100 100 100 100 0 .49 47 28 42 17 6 .50 - .99 20 38 8 24 19 1.00 - .1.49 17 14 19 26 28 1.50 - 1.99 8 8 15 12 16 2.00 - 2.49 2 4 11 9 2.50 - 2.99 2 3 29 3.00 - 3.49 4 23 3.50 - 3.99 2 1 3 4.00 - 4.49 6 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 - 5.49 5.99 6.49 6.99 7.49 7.99 8.49 8.99 9.49 9.99 2 2 1 12 2 2 2 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 - 14.99 19.99 24.99 29.99 34.99 39.99 44.99 49.99 1 2 2 Bulk Gas Handlers B-3 100 5 50 18 14 5 7 2 Persons Exposed to Lead Dusts C 100 ( ( ( ( (40 ( ( ( ( ( ( ( ( (23 ( ( ( ( ( 8 19 4 2 .2 2 0018152 60 TABLE 17 DISTRIBUTION OF PERSONS ACCORDING TO LEAD MGS./ 100 GM. DRY FAECES. Medical Student A-l Fil.Sta. Garage Att.and Meehan- BulkGas ics Handlrs (Control) A-2 & A-3 A-4 Filling Station Attend- ants B-l Garage Meehan- ics (Test) B-2 Total 60 71 26 66 32- 0 .49 28 20 11 - ii 2 .50 - .99 12 27 2 16 6 1.00 - 1.49 10 10 5 . 17 9 1.50 1.99 5 6 4 8 5 2.00 - 2.49 1 3 73 2,50 - 2.99 1 2 13 3.00 - 3.49 111 3.50 - 3.99 1 1 1 4.00 - 4.49 4.50 - 4.99 \2 5.00 5,49 1 5.50 - 5.99 1 6.00 - 6.49 31 6.50 - 6.99 1 7.00 - 7.49 7.50 - 7.99 1 8.00 - 8.49 1 8.50 - 8.99 9.00 - 9.49 9.50 - 9.99 10.00 14.99 15.00 - 19,99 20.00 - 24.99 25.00 - 29.99 30,00 - 34.99 35.00 - 39 99 40.00 - 44.99 45.00 - 49.99 1 1 1 " Bulk Gas Handlers B-3 44 2 22 8 6 2 3 1 Persons exposed to lead dusts C 48 ( ( ( (19 ( ( ( ( ( ( ( ( ( ( (11 ( ( ( ( ( 4 9 2 1 1 .1 K E 0018153 61 TABLE 18 PERCENTAGE DISTRIBUTION OF PERSONS ACCORDING TO LEAD IN FAECES (MGS./gM. ASH) Medical Students A-l Fil.Sta. A t t .and BulkGas Handlrs A-2&A-3 Garage Mechan ics (Control) A-4 Filling Station Attend- ants B-l Garage Meehan- ics (Test) . B-2 Bulk' Gas Handlers B-3 Persons Exposed to Lead Dusts C Total 100 100 100 100 100 100 100 0 - .04 42 41 46 27 9 23 .05 - .09 32 37 23 41 38 43 10 .10 - .14 15 11 4 11 25 18 4 .15 - .19 5 6 8 9 6 11 6 .20 - .24 2 429 .25 - .29 14 3 626 .30 - .34 14 24 .35 - .39 \ 23 8 .40 - .44 2 1 23 4 .45 - .49 6 .50 - .74 2 82 17 .75 - .99 10 1.00 - 1.49 28 1.50 - 1.99 1 2 10 2,00 & Over 4 H E 0018 i54 62 TABLE 19 DISTRIBUTION OF PERSONS ACCORDING TO LEAD IN FAECES (MGS./gM. ASH) Medical Students A-l Fil.Sta, A t t .and BulkGas Handlrs A-2&A-3 Garage Meehan- ics (Control) A-4 Filling Station Attend ants B-l Garage Mechan ics (Test) B-2 Bulk Gas Hand lers B-3 Persons Exposed to Lead Dusts C Total 59 71 26 66 32 . 44 48 0 .04 25 29 12 18 3 10 .05 - .09 19 26 6 27 12 19 .10 .14 9 8 1 ,7 8 8 .15 - .19 3 4 2 6 2 5 .20 - .24 1 113 .25 - .29 11 221 .30 - .34 11 1 .35 - .39 11 .40 - .44 .1 1 11 .45 - .49 .50 .74 1 21 .75 - .99 * 1.00 - 1.49 1 1.50 - 1.99 1 1 2.00 & Over 5 2 3 3 2 4 2 3 8 5 4 5 2  63 TABLE 20 PERCENTAGE DISTRIBUTION OF PERSONS ACCORDING TO MGS LEAD PER LITER 'OF URINE. Medical Students A-l Fil.Sta. Att. and BulkGas Handlrs A-2&A-3 Garage Mechan ics ' (Control) -A-4 . Filling Station Attend ants B-l Garage Mechan ics (Test) - B-2 Bulk Gas Hand lers B-3 Persons Exposed to Lead Lusts G Total 100 100 100 100 100 100 L0'"*' 0 - .02 17 6 31 634 .03 - .05 34 29 15 34 16 26 2 .06 - .08 25 26 19 25 25 22 il LO UJ .09 - .11 15 10 8 "12 28 11 .12 - .14 2 9 19 6 16 13 15 .15 - ,17 .18 - .20 2 2 4 7 3 3 7 15 2 46 .21 - ,23 ^ 2 ,24 - ,26 63 4 1 * r .27 - .29 2 G .30 - .32 .33 .36 .39 .42 .45 - .35 ,38 .41 ,44 .47 1 32 22 22 AX 2 .54 - .56 1 .57 - .59 . 6 6 - .68 2 1 2 o .72 - .74 .84 - , 8 6 1 2 rt .87 - .89 23 .96 - .98 2 1.02 - 1,04 4 1.62 - 1.64 1 KE1 0018156 i V. 64 TABLE 21 DISTRIBUTION OF PERSONS ACCORDING TO MGS OF LEAD PER LITER URINE Medical Students A-l F i l .Sta. Garage Att.and Mechan BulkGas ics Handlrs (Control) A-2&A-3 A-4 Filling Station Attend ants B-l Garage Mechan ics (Test) B-2 Total 65 69 26 65 32 0 - .02 .03 - .05 .06 - .08 .09 - ..11 .12 - .14 .15 - .17 .18 - .20 .21 - .23 .24 - .26 .27 - .29 .30 - .32 .33 - .35 .36 - .38 .39 - ,41 .42 - .47 .54 - .56 ,57 - .59 .66 - .68 ,72 - .74 .84 - *86 .87 - .89 .96 - .98 1.02 - 1,04 1.62 - 1.64 11 22 16 10 1 1 1 1 1 1 4 20 18 7 6 3 5 1 1 1 1 1 84 4 22 5 16 28 54 2 1 '4 1 1 1 1 1 1 1 5 8 9 5 1 1 1 1 Bulk Gas Hand lers B-3 Persons Exposed to Lead Dusts C 46 53 2 12 1 10 6 53 68 38 23 5 7 3 11 11 11 1 1 11 1 KE" 0018157 65 TABLE 22 RELATION BETWEEN LENGTH OF EXPOSURE TO ETHYL GASOLINE, AND BLOOD AND CHEMICAL FINDINGS. Stippled erythrocytes per 50 fields Lead in mgs. per gm. ash of faeces Mgs. lead per liter of urine Exposure to ethyl gasoline (years) Less s UP 1 up It UP 2 up 2g up 3 up than to 1 to li to 2 to 2-g to 3 to 3g TOTAL 0 1 2' 3 4 5 6 7, 8 9/ . TOTAL 2 C 4 STIPPLING 34 3 216 1 2322 12 111 12 1 * 1 5 5. 8 6 4 12 21 10 .3 6 2 1 44 .01-,04 .05-,09 .10-.14 .15-,19 .20-,24 .25-. 29 .30-,34 .35-.39 TOTAL LEAD CONTENT OF FAECES 1 1 4 1 4 11 2 3 2 2 3 2 3 17 3 36 1 12 11 11 1 .1 3 4 3 7 8 3 11 39 .01-,04 .05-,09 .10-.14 .15-.19 .20-.24 .25-.29 .30-,34 .35-,39 .40-,44 TOTAL LEAD CONTENT OF URINE 1 1 1 3 2 2 1 11 1 2 1 2 5 2 4 17 1 22 1 3 9 1 1 13 11 45 11 4 6 9 4 10 42 K 0018158 TABLE 23 RELATION BETWEEN DEGREE OF INTENSITY OF EXPOSURE TO LEAD DUST (POSITIVE CONTROL GROUP)* AND BLOOD AND CHEMICAL FINDINGS. Stippled erythrocytes per 50 fields None 1- 9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100-109 TOTAL Lead in mgs per gm ash of faeces .01- .09 .10- .19 .20- .29 .30- .39 .40- .49 .50- .59 .60- .69 .70- .79 .80- .89 .90- ,99 1.00-1.09 1.10 / TOTAL Mgs Lead per Liter of Urine .01-.09 .10-.19 .20-.29 .30-,39 .40-.49 .50-,59 .60-.69 .70-,79 .80-.89 ; TOTAL Lead Dust Exposure (Degree of Intensity) 1 2 3 _ 4 5 _ 6 7 _ 8 TOTJ STIPPLING 12 1 7 5 - 1 1 1 28 10 2 19 25 5 4 1 1 67 1 1 5 5 2 3 5 1 23 1- 11- - 2- 5 - 11 21 5 1 12 22 11 1 12 2 13 11 2 11 24 5 36 41 9 9 11 6 141 LEAD CONTENT' OF FAECES 12 1 3 1 - - 2 19 8-- 31- 2 14 1- 21 1Q- 5 - 1221--- 6 *4 1 5 1 12 4 113 16 1 12 11 2 11 1 3 11 2 133 2 2 3 14 21 4 16 12 4 3 7 1 68 LEAD 1TONTENT OF URINE 13 - - 4 1 1 2 1 22 5 3 10 . 7 2 2 4 2 35 - - 6 3 3 1 3 1 17 1 11 3 111 3 - 11 2 1l 11 21 4 17 17 7 5 9 4 84 * Includes some persons in Group A. See text.