Document OJ193RaYQLpE14DZ9Oe7anZ7e

September 2 , 1 9 ^9 Mr. . 0 . Jones ...- . Ethyl Corporation Chrysler Building New York (1 7 ) New York Dear Ollie: ' I have just had a rather brief conversation with Dr. Kehoe and he has told me something of your efforts to find tank repair crews which would be desirable for study in order to further our small tank survey. Since the nature of my work requires a certain amount of time budgeting, it'would be helpful to me if I were to be advised as to your progress in locating these crews. In fact, if I could anticipate the improbability of arrangements being made before the first part of October, I could occupy the next thirty days to best advantage by getting some of the field work done. If the field work is started, however, it would be most economic not to interrupt by returning to get the tank work under way again. I should like to confirm some concepts which I am sure you recognize and which I believe Dr. Kehoe outlined while in New York. It will suit our purposes best to work with crews which (1 ) operate with the least adherence to principles of safety5 (2) have operated in the past with the least contact with our Safety Engineers; (3 ) operate in the most accessible territory to Cincinnati; and (l}.) which have the most consistent schedule of small tank repair. Before any definite arrangements are made to work with any of the tank repair companies, I should like to have all available Information about the company and Its scheduled work and discuss it with you. The last advice I had from Tank Cleaners, Incorporated of Jacksonville, led me to believe that they might regain the contract which they previously had and might go ahead with the work which we had expected to follow during the past August. I have made no effort to determine what their status is at present, since I think there should not be too many sources of inquiry. I do hope that you * *^ w.*n 1 ^r *wJ,**&**,^* < *** ^j ^K|'J, ^-*T- *"'t>*, vV "*%*.&>4$.^*4* (*** -**,* *-- ^ f* _ *v,4. .* :. Kr. E. 0 Jones ,,- (2) > September 2,*-19^9 Vv%^- -4 are inquiring into the possibility of working with them, because their previously scheduled work appeared to be most desirable from our point of view. . Please then keep me advised so that I may budget my time to best advantage. ,, ,, . ' ,, "' Cordially yours, i^r i*. LWSsvr /'h,' cc - Dr. R. A. Kehoe 5'*-,'"../ i~fe,i.;,>$ "' - Lester W.^anders, K.>. PRELIMINARY REPORT ON SMALL TANK STUDY This study has been undertaken in an effort to determine the level of lead exposure and level of lead absorption occurring in men continually engaged in the cleaning and repair of petroleum products storage tanks of a capacity of one thousand bbls or less. The results will be used to evaluate the necessity for supervision of such activity. The general plan of the study follows. Tank cleaning crews have been chosen whose total working time is spent in the work mentioned above. The crews currently involved are those of the Mid West Construction Company of Indianapolis. Crews of the Phillips Construction Company and Standard Oil Company will be used later if arrangements can be made. Only one crew, which is composed of from // three to four men, can be followed at one time becauseofthe geo graphical distribution of crews and limitation of time of one in dividual and the inability to assign additional men to the job. Each crew is studied for four weeks. A physician makes a preliminary physical examination of each crew member and therafter makes an examination once weekly for four weeks.Eachman is asked to pass a urine sample in the morning and eveningof eachday for the purpose of lead analysis of the urine. A safety engineer is assigned to and follows each crew from job to job. The safety engineer is assigned the responsibility of recording the specific activity of each crew man throughout the working day/ of analyzing the tank air before cleaning, immediately after cleaning, after blowing and after completion of work, and at any other time which may appear to him to be an advantageous time for 0006779 N 7677.01 2- A t sampling. He also records In-tank and outside temperatures, vind conditions and air humidities. He has been instructed to allow the men to do their work with no interference or instruction (unless there Is reason to believe that immediate hazard exists), because it Is necessary to evaluate exposure and absorption under conditions as they exist in the absence of supervision. At this time one crew has been followed for four weeks and a second crew will have been followed for four weeks on November 3 rd. Data on ten leaded gasoline storage tanks In nine Michigan towns were obtained while studying the first crew and data on five similar tanks located in five Illinois towns have been received at this time from the study of the tanks of the second crew. The lead content of the tank air at the time men have worked in the tanks without protection has ranged from a low of approximately 3.0 milli grams per 10 cubic meters (8 micrograms per cubic foot) to a high of 14 mg per 10 cubic meters ( 4 0 micrograms per cubic foot). The approxi mate arithmetic average of the lead content of the air during the time men worked in these tanks without protection was 8 mg. per 10 cubic meters. Relatively few of the analytical results have been obtained on the urines. Those which have been obtained indicate clearly an increased lead absorption and there is a trend toward correlation between time spent in the tanks and lead content of urine. The urine of the four men (first crew) on whom results have been obtained show arithmetic averages of 0.117, 0.112, 0.072 and 0 . 1 6 1 mg. of lead per liter respectively and ranged from a low of 0.03 with urine of low specific gravity to a high of 0 . 3 4 with a urine of high specific gravity. The urine results appear to be consistent and there is no With one exception, history and physical examination has revealed no evidence of lead affect. The exception complained fre quently of not feeling well, dreamed excessively, had frequent belly pain, had slight pupillary irregularity and inequality and passed a higher concentration of lead in urine than any other member of his crew. It has become apparent in the short time observations have been made that at least some of these crews operate very earelessly and it is probable that no crew could operate with less regard for possible lead exposure than the first crew observed. Insufficient information has been gained at this time to support any opinion as to the degree of hazard involved in small tank cleaning and repair. A more complete and detailed Interim report will be made at an early date. November 3* 19^8 Lester W. Sanders, M.D. KET 00C67 i This study is being ma /W 77T `JLgr _ ng the lead hazards inherent i ^ u * ^DohnO^huALi. MrtK petroleum products storage barrels or less* which have y id ubsequently for the purpo; ot it is necessary for the safety of workmen, that these tank operations be observed in the future as they have in the past. Scone of Small Tank Maintenance Procedures The Safety Division of the Sales Department of Ethyl Corporation has collected data from the available sources on the numbers of lead-contaminated small tanks involved in repair jobs per year in the United States and Canada and also data on the numbers of men involved in this work and the proportion of time spent at this work. *The term small tank as it is used in the text refers to any petroleum products storage tank of a capacity of 1,000 barrels or less and does not refer to a leaded tank unless 3 0 designated. N 7677.02 2 The number of pertinent small tank jobs was already on record because a system has been in operation for a number cf years which required the reporting of all entries into tanks ?;hich had contained loaded gasoline. This notification of tank entry has been accomplished by searching out all individuals in the oil industry who are immediately responsible for the maintenance of storage tanks. These individuals are referred to as "authority men" and a close contact is maintained with them and they are continually reminded cf their responsibility. The close contact and the intimate relationship which has been maintained with these men, rather than compulsion, are the determining factors in the accuracy of the data compiled. There is reason to believe that the data are reasonably correct and valid for the purpose. A copy of the report of the Safety Division is attached. Our own knowledge of the T-D Construction Company shows 3; .- - that their reporting of full time men, as defined in the report, is not correct. These men are engaged regularly in small tank work but not on ''leaded" small tanks. Since our data reveal that only about one-third of all small tanks repaired are leaded tanks, we must presume that the three men employed by this company work on leaded tanks only onethird of their time, in spite of the report made for this company and in spite of the fact that, while under observation, 10 of 18 tanks repaired were leaded, 7 not leaded and one undetermined. The report on Petroleum Systems Incorporated is contradictory, and further Investigation reveals that they have no full-time men by definition and that only 1 per cent of the time of their 12 to 60 employees is spent at small tank work (note from Dollahan, May 2 9 1 9 5 0 ), We have knowledge of one contracting company (one crew of this company was included in this survey) which was not K 0006784 -k- Included In the Safety Division^survey. They employ from If? to 27 men, they repair about 900 small tanks per year and the men spend full time on small tank work. It is estimated that one third of the tanka entered are leaded tanks. The report of the Safety Division will be modified only to the extent of excluding the men reported as full-time men from this category and placing them in the part-time category and also of including the one operating organization which we surveyed ourselves. We have knowledge of 7 tank repair organizations which are not included in the Safety Division's survey, but we have no knowledge of the scope of their work and they do not appear in the report. There were also 2 7 organizations that reported a total of 110 men employed at small tank work who are not Included in the Safety Division's report because none of these men were reported as spending more than 10 per cent of their time at small tank work. K y* ,a a r-f*-- t~0 J 0 0 i 6'0 * -5- The Safety Division's survey Includes the reports of 8 l5 agencies. The addition of one agency surveyed by us makes a total of 8l6 reports. The Safety Division's survey reports an average of 1550 tanks per year for the years I9I4-5 # and 1 9 U-7 (The immediate previous years were excluded as abnormal years because of the war and I9I5.8 and X9li_9 were excluded because of some of the notifications for those years were made to a competing company.) The agency surveyed by us reported 9 tanks repaired per year, one- third of which were leaded tanks. This br-ings the total up to 1850 leaded tanks per year. The adjusted number of men who spend any considerable amount of time in small tank repair is 110 after the addition of the one previously unreported company and the exclusion,, because of correction, of the one company that originally reported 12 to 60 full time men. These 1 1 0 men spend an average of 3 per cent of their time working on leaded small storage tanks. K 0006786 -6- It is recognized that all men involved in small tank work have not been included, nor has the total number of tanks, but there is reason to believe that the report includes the great majority of men and tanks. If the 1 1 0 men not included in the report of the Safety Division are included and surmise made as to the unreported agencies, it is believed reasonable to presume that no more than 2$0 to 300 men spend any considerable time at this kind of work, and, because of the nature of the work, that no one is employed who spends more than one-third of his working time at the repair of leaded small tanks. There are usually about ? tanks at each bulk plant and, of the 7* 2 are used for the storage of leaded product. Scope of this Survey Of the presumed 2 5 0 to 3 0 0 men employed at small tank repair only 18 have been studied. The predominant /< 0006787 7- reason no more men have been found is because the majority of either contracting or oil companies are not consistently engaged in small tank work and in order to study maximal exposure it is necessary to observe these men during a period of consistent small tank work. Th fact that only 300 men are engaged with any consistency at all in small tank work and that all efforts proved futile to produce more than 18 men in almost 2 years is not -without significance in the evaluation of the over all picture. It has been possible to study only 18 men because: (1 ) There are only a few organizations whose small tank -work is consistent enough to offer opportunity of study over a sufficient period of time to acquire information based on maximal exposure (2 ) Some agencies are not cooperative and are unwilling for studies to be made; (3) Some Individual workmen will not submit to study; (ij.) In at least one Instance the tank owners would not allow the study to be made. There will be opportunity for further study in the future because there will occur sooner or later the necessary combination of circumstances (an agreeable contracting agency, agreeable working men, agreeable tank owners and a contract covering a sufficient number of consecutive small tanks to produce adequate data and maximum exposure). -8- Evaluation of Exposure Direct Method These small tank workmen usually work in crews composed of three men. Occasionally there are four men to a crew and occasionally only two men. The men were studied Individually during the period of intensive observation of the work of the crew to which they belonged. Time was kept on their various activities throughout each day over a period of approximately day3 and determination of the concentration of lead in the atmosphere of the tanks were made at the time that men were within the tank or as near that time as was practical. * - Working activities were broken down into nine different categories in relationship to the possibility of lead exposure inherent in the various categories. It was presumed that tank cleaning, sludge handling and 0086739 -9 - all other activities within the tank might afford some possibility for lead absorption either by inhalation or skin absorption* It was also presumed that paint burning outside the tank might afford a source of lead for absorption by inhalation* Table 1 shows the job time distribution for each workman for the total period of observation. Our records show that the number of hours spent by any man within a tank during any single day during the course of these observations did not exceed 7 hours, and was usually less than 3 hours, and that the maximum total time spent at tank cleaning (Job #1 ) by any one individual did not exceed 1 hour, 36 minutes* The average time per day per man (including only those who did some tank cleaning) was 6 minutes and the average time per tank per man was 3 minutes. The total time .t spent in all inside work (Jobs 1 , 2 , ij.) (where there is K 0006700 - 10 * a probability of organic lead absorption) including cleaning, repair, miscellaneous inside activities and sludge handling is shown in the table- and is seen not to have exceeded 2 0 hours for any one man during the total period of observation. The remaining presumable source of lead on this job is that of inorganic lead volatilized and dispersed by the paint-burning operation, which is done prior to welding, and, of course, the volatilization of what ever lead which remains after burning by the welding flame during the welding operations. This is an outside operation. Time spent at paint burning is also shown in Table 1 (Job 3 ) and this is seen to occupy considerably more time on most days and over the longer periods of time than does any inside work. The maximum time spent in paint burning by one man on any one day was shown to have been 9*7 hours, and the maximum time for KE" 00C8731 11 - any man over the total period of observation was 1093 hours. No satisfactory determinations were made of the lead content of the utmosphere produced by paint burning because of the difficulties encountered, Men are rigged on the tank in such a manner that a second operator attempting to gather air samples at breathing level would interfere with work. The only opportunities which occurred for obtaining representative samples of this air happened to occur when other conditions were not favorable such as the necessity of obtaining other samples, the occurrence of winds of high velocity, etc, A considerable number of determinations of the concentration of load in the atmosphere of tanks was made and reference to Tables No. 2 , 3 * k, 5 , and 6 'ill show the range of these concentrations. The concentration existent at the time of cleaning operations is more apt to be represented correctly by the determinations made immediately after cleaning than those made before cleaning, - 12 Crews #1 , #2 , and #3 habitually wore air-line masks during all cleaning procedures but Crews $$ and #6 wore no masks at any time* The average concentration of lead in the atmosphere of tanks immediately after being cleaned by Crews #1 , #2 , and #3 * is seen to be 7 8 mg. per 10 cu. m. of air. The range of lead concentration is seen to be from 0.7 to li^.l r.;g. per 10 cu. m. of air. In the case of the tanks entered by Crews # 5 and #6, the average concentration of lead immediately after cleaning, is seen to be 37 mg. and the range from 0 to 22.6 mg..* After cleaning, the tanks are blown or aired for various periods, and the concentration of lead in the atmosphere of the tanks after this ventilation is listed in the tables as HLater.w Both inside and outside Since Crew #i{. worked for only a few days on leaded tanks, the data on these tanks are not tabulated. KE 03C67S3 13 - repair work Is done after this ventilation, and it appears, from tlae observations made in thi3 survey, that masks are never worn at this time by any of the tank repairmen. Presumably, under vmusual- conditions, they are used, this being dene at the discretion of the worker. Following the ventilation, as might be expected, the concentration of lead within the tank is subject to fairly wide variation. The average con centration is seen to be 1^.3 mg. per 10 cu. m. and the range to be from nil to II4..I mg. per 10 cu. m. The repair work on the inside of the tank, while being the least frequent inside work, is likely, nevertheless, to Involve a longer period of exposure than that associated with any other type of work, and moreover, during this period, it is the exceptional practice to control respiratory exposure by the use of masks. 000679.4 Ili. - Sludge handling has been classed in a specific category of jobs, since it might be a source of lead absorption, particularly through skin contact. .' 4 observations have been made, it is regarded as Since the relatively unimportant, because of the small volume of sludge handled on these jobs and the short period of time involved in its handling, in spite of the fact that, on the whole, it is handled fairly carelessly and, in most instances, inadequate protection for the skin is used. If the probability of a rapidly developed Inorganic lead intoxication is to be estimated, the maximum length of exposure within the tank to the maximum lead con centrations found in all of the tanks observed will have 'SI to be considered. Our records show that the maximum C3 C5 time spent In any one day within any of the observed O U tanks was a little over 7 hours. The maximum concentration of lead is seen to be II4..I mg. per 10 cu. m.* Since 15 maximum time approached a full working day occasionally, we can presume that a full working day might occasionally be spent at work within the tank, and that the respiratory volume during such a day would be 10 cu. m. The work is not particularly hard, so that the respiratory volume of air per day, in all probability, would not exceed this amount. The figure for the concentration then, as given, becomes the absolute amount entering the air passages, and would certainly have to be regarded as insufficient in itself, to produce intoxication. The dosage of llj.,1 mg. might be regarded roughly as not more than l/ 5 0 of a dangerous single dose of lead. The next question for consideration is that of the frequency of occurrence of such periods of maximal exposure, this question bringing in its train the matter of the total period of months or years during which accumulation of lead in the tissues can take place. The maximum time spent by any workman within a tank during the period of the 16 - observations (30 days) was a little more than 20 hours (Table 1 ). Here again, if the maximum concentrations found were to exist during the entire maximum working time, and even if the total number of hours of work and exposure during the 30-day period were to be put in on consecutive days, the dosage would still be too small to produce immediate illness, the dose being roughly (within our admittedly incomplete knowledge of the human response) about l/2p of a dangerous dose of organic lead. It appears that there Is really no opportunity for the development of acute intoxication since various hypothetical combinations of extreme and unlikely conditions would seem to be incapable of Inducing such an intoxication. The concentration of lead in the atmosphere of these tanks is in many instances, far In excess of that - 17 - which Is regarded as safe for dally long-term exposure. Therefore, it will be necessary to consider the probabilities for the absorption of lead in excess of that amount which under normal circumstances is excreted and therefore safe. The average time spent within the contaminated atmosphere, and the average extent of the contamination of the air with lead should be helpful in arriving at some judgment as to the possibilities for long-term accumulation of lead. The average time spent within the tank per man per day for the purpose of cleaning is shown (Table 1 ) to be about $ minutes, excluding those men who did no tank cleaning, and the average time per day spent within the tank for all purposes and including time spent at sludge handling (because the sludge handler spends 3 ome time over the manhole and therefore is exposed to the tank atmosphere and also may subject his skin to contact with the sludge) J1 0 0 0 0 < 9 k) 18 - is shown to be less than yo minutes. The range of lead concentrations in the atmosphere of the tanks at the time that men are most likely to be within the tank is so great (varying from 0 to 22 mg. per 10 cu. m.), that the highest value which has been found to have occurred in these tanks cn more than one analysis will be used to evaluate probable average absorption, recognizing that the result will be grossly exaggerated on the high side. Using the average time spent v/ithin the tank and the maximum atmospheric concentration of lead of lip*1 mg. per 10 cu. m . , the total average daily amount of load which could be absorbed, assuming that the respiratory volume during 30 minutes is 300 L., would be 0.l\2y rag* On the basis of the observed lead concentration in the respired air and the duration of the period over which such air is breathed, it seems reasonably certain that there would be neither rapid absorption of sufficient K' 00G6799 - 19 - quantities of lead to produce an intoxication, nor significant accumulation of lead in the body over a long period of time, if the tank atmosphere is the only source of lead. It should be pointed out that all sorts of irregularities occur during work of this type. Pew contracting companies and still fewer oil companies engage consistently in work on small tanks. So far as is known, only one contracting company and one oil company employ crews for the exclusive purpose of repairing small tanks. Most of the work is sporadic. Only about l/ 3 of all tanks repaired have been used for the storage of leaded product. While almost all of the small tank3 are cleaned there are relatively few which undergo inside repair work. There are inevitable interruptions in the work, such as days spent at travel from one point to another, periods of bad weather which 0006*00 20 - prevent work, and, in the instance of 3 crews of one company, one week out of every four which is taken off to offset the twenty-one days of work without respite. On the whole, hygienic working methods are not good. In many instances, air-lino respiratory equipment is not kept clean nor In good condition. Clothing and gloves are v;orn day after day without cleaning or replacement. Daily bathing facilities are frequently not available. The concentrt ions of lead in the atmosphere of tanks is frequently considerably beyond the maximum allowable concentration. The cleaning methods are not very good, and it i3 questionable if many of the tanks should be declared free from lead hazard after cleaning. For these reasons, an estimate of the possible exposure of an Individual based on the most extreme conditions observed, is not to be regarded as an excess of caution. - 21 Indirect Measurement of Exposure It is neither irrelevant nor wholly without signi ficance to point out that all available knowledge would point to the total lack of occurrence of illnesses or fatalities due to load intoxication in men who have carried out work on small tanks. Urinary samples were collected once daily from the men of some of the crews under observation and twice daily from others. The samples were small, being a portion of a single voiding, and were of a volume of 100 c.c. or less. The concentrtions of lead in such samples from the same Individual are subject bo fairly wide variation but sufficient numbers of results on the urine of each man are available to indicate the true excretory level and to yield a stabile mean value. On tne average, [.1 samples per man were collected from 18 men. Actually, 71)4 samples were obtained, a few 0006302 - 22 - samples being missed, and additional numbers being obtained, in some instances. The mean concentrations of lead in the urine of each man, of the men of each crew, and of all of the men studied, are shown in Table 7 * The mean concentration of lead in 714}- samples of the urine of the 18 men is 0.108 mg. per liter. There i3 little question about the validity and significance of this mean value. It exceeds the lead concentration found in the urine of normal unexposed people (0 . 0 3 mg. per liter), and Is high enough to indicate clearly that these men are working In an environment which is responsible for some accumulation of lead. The level of lead excretion of some of the crews approaches the threshold of hazardous lead absorption. The mean values for the urine of the crews range from a low of 0 . 0 7 9 to a high of O.llj.7 mg. per liter, the high values being those of crews No. 3 , 5 and 2 (0 .1 2 3 , 0 1 3 2 arid O.llj.7 mg. per liter). The 0006803 - 23 - individual samples of 8 men reached levels of 0.20 mg. per liter or higher from time to time, and there were only v f she 18 men whose urinary lead did not at any time reach a concentration of 0.20 mg. per liter of urine. The urine of a few of these men reached lead levels which are consistent with the onset of lead intoxication, but only one maintained such levels consistently enough to indicate that these concentrtions truly represented the overflow of absorbed lead. Values as high as 0 . 3 0 were not infrequent, and the lead concentration in the urine of one subject exceeded 0.15 mg. per liter consistently for llj. days and attained a maximum of 0.50 mg. per liter. There were statistical differences in the mean urinary lead values of some of the crew3 , but by inspection no correlation between any of the job categories and lead levels can be seen either by individual or collective (crew) records. 21}. -- Several of the individual records are worthy of note. One man was seen before he started on the small tank job and before he had had any discoverable exposure to lead. The foreman of this crew was asked to keep this man out of the tanks and on outside paint-burning jobs as consistently as possible. This man worked for 3 weeks under observation at paint burning (predominantly), outside welding and miscellaneous work, then spent 3 t ime weeks in the shop primarily at oad/jobs of maintenance, and then was under observation for an additional 3 weeks while back at paint burning and other outside work on the tanks again. There apparently was a gradual increase in the rate of the urinary lead excretion during the period. The concentration of lead in the urine of the man, when first seen, was 0.07 mg. per liter, and that in the blood was 0 . 0 3 mg. per 100 g. The mean concentration 0306805 - 25 - of lead in urine for the first 3 weeks * period was 0.067 mg* per liter. No blood sample v;as obtained at ,, the end of the first period of observation. The mean concentration of lead in urine at the end of the second period was 0.13l{. rng. per liter and that in the blood was 0 . 0 5 mg. per 100 g. It appears then that lead was being absorbed on the job, even though no inside tank Yiork was done and the only apparent source of lead absorption was that of the volatilized paint. Another subject, who during 3 weeks of observation, spent 11? hours in burning paint, showed the mean concentration of 0.22 mg. lead per liter of urine. Over a period of 10 days, this man excreted lead in the urine at a high concentration, reaching that of 0.50 mg. per liter several times toward the end of the period of observation. Only one blood sample was obtained from this man. Thi3 was obtained at the beginning of the period of observation and showed at that time a 26 - concentration of 0 .0 ^ mg. per 1 0 0 g. A urine sample was not obtained at the time the blood sample was obtained, A v/eek later, when urine samples were obtained, they showed concentrations ranging from 0.03 to 0.15 for the first 3+ days. Since the low blood level was obtained some ll| days before the urinary lead began to rise it should not be considered in relation to the urinary concentrations. This man also had the second largest number of stippled erythrocytes (1,100 per million) observed in the blood of any of the men. ' The man who spent the maximal time (2 0 .ij. hours) working within the tank showed the lowest mean urinary lead concentration (0.063 mg. per liter), and the twice daily samples were so consistent that a con centration of 0.11 v/as never exceeded. The last four men appearing in Table 1 are also of some interest. It will be seen that Nos. 1 5 and K 00 0 6 nI 27 - 16 spent, respectively, 55*3 and l}-5.6 hours on work presumed to be the specific jobs involving lead exposure. The mean concentrations of lead in urine (0.132 and 0.113), as well as the cbncentrations of lead in blood (four samples for one and three for the other) are indicative of a definite exposure to lead. On the other hand men Nos. 17 and 1 8 , who spent more time within the tank than did No. l6, but much less time at paint burning than either Nos. 1 5 or 1 6 , did not show clear evidence of occupational exposure to lead in the lead content of their urine (0.063 and 0.057 mg. per liter) and blood (range 0 . 0 3 to 0 . 0 6 and O.oij. to 0 . 0 6 5 mg. per 1 0 0 g.). These four men are the only men of the entire group who con sistently did not use airline masks. In fact, no masks were In their possession. While, In general, the atmospheric lead concentrations to which these men were exposed were not as high as those to which some of the other men were exposed, these four men by coincidence worked on leaded Kf 0006S08 tanka with greater consistency than any of the others, and in some of the tanks repaired by men Nos. 15 - 19 the highest concentration of atmospheric lead found in any of these tanks occurred. Subject No. 19 spent 1/2 hour in a tank without mask in the morning when the lead concentration in the air was somewhere between 5*6 and 8 .1}. mg. per 10 cu. m., and during the afternoon of ' the same day spent l/ 2 hour in a tank characterized by 2 2 .6 mg. of load per 10 cu. m., the highest con centration found. This man was one of those who refused to cooperate in the investigation, and nothing i3 known of his response to this exposure other than the fact that he failed to develop symptoms of illness so far as could be established by the casual observation of u layman* This man's fellow worker, on v/hom adequate information was obtained, did not enter this tank. - 29 - State of Health of the Workmen Enough men have been examined to provide data for statistical analyses of the lead concentration in urine only. Inspection shows that before this study was started the subjects had spent from nil* to 6 years on the job, their mean period of time on this job being almost 2l months. The group can be broken down further into 7 men who have spent from nil to 12 months on the job and 11 men who have spent from 2 to 6 years on the job. All subjects had been welders before their present employment for from 2 to 16 years, and all but two gave no history of previous lead exposure excepting that involved in general welding. One had worked previously as a painter and one as an electrician. Again by inspection, these two groups do not differentiate themselves by occurrence of symptoms, *One man was examined before he started on this job. K & 0006310 - 30 - the presence of physical signs, level of hemoglobin, occurrence of stippled erythrocytes, or lead content of their urine or blood. It is therefore presumed that men at this work reach higher lead levels in urine and blood fairly quickly and then excrete variable amounts of lead but remain usually at a higher level than that of imexposed persons. Further, the group as a whole does not differentiate itself from any other non-specialized group by the above factors, excepting by the concentrations of lead in urine and blood. The occurrence of symptoms in 18 men (the 18th man was never seen because of his absence when visits were made) is shown below. . Insomnia - 1 Excessive Dreaming - 1 Headache - 3 Fatigability - 1 Anorexia - 1 Breakfast Anorexia - 3 Abdominal Pain - 6 Irritability - Nil Weakness - 1 Myalgia - 3 * Vertigo - Nil Anxious Expression - 1? Constipation - Ij. Diarrhea - 3 Metallic Taste - Nil Vomiting - 1 Nausea - 3 Use of Cathartics - I4. Lassitude - Nil Arthralgia - 5 Impotence - Nil KE" 000.331 31 - The occurrence of physical signs ia shown in the follow ing table. Tremor - 2 Pallor - Nil Diminished Reflexes - 2 Increased Reflexes - 3 Lead Line - Nil Extensor Weakness - Nil Malnutrition - Nil Abdominal Tenderness - 1 Temperature, pulse rate, blood pressure, hemoglobin, and stippled erythrocyte ranges are shownibelow (Table 8 ). The incidence of symptoms might appear to be high, but many of the recorded symptoms are clearly the result of disturbances other than those produced by lead, and others are only very questionably the result of lead absorption. The single occurrence of excessive dreaming occurred in a subject whose clinical picture most closely simulated the picture of organic-lead intoxication. This man will be discussed later. The occurrence of headache in three of thirteen subjects does not appear to bo excessive and one of these instances occurred as a single isolated attack. The other two were chronic, repeated attacks, which could conceivably be related to industrial exposure. The single - 32 - occurrence of fatigability occurred in the subject to be discussed later. The single occurrence of anorexia was due to minor acute illness (food poisoning). Breakfast anorexia occurred in 3 subjects, but in 2 instances was habitual and apparently not related to work, and in the third instance occurred only in very hot weather. Abdominal pain occurred in five subjects, but in two instances the pain was clearly associated with an acute enteric disturbance associated with diarrhea and characterized by a typical course. One instance wa3 associated with flatulence of long-standing and was not suggestive of the abdominal pain of lead intoxication. Pain, in one instance, was high epigastric pain such as is associated with ulcer. Two instances of abdominal pain cannot be clearly differentiated from pain produced by lead, but were not typical. None of the four instances of constipation was the obstinate type usually associated with lead intoxication. Of the four instances of vomiting or nausea, - 33 - one was rather clearly the result of habitual drinking, one was associated with exposure to gasoline vapors and quickly cleared, but the other two could have been associated with working environment. The two occurrences of tremor were not marked. Of the four recorded instances of -weight loss, the greatest was lo pounds, this being almost certainly recorded in error. One loss of six pounds could be associated with shift from relatively easy to hard 'work. Two of the losses could be attributed either to the hard v/ork and long hours on this job or to lead absorption. The high incidence of arthralgia was attributed to the cramped position in which these men work. The men themselves believed this to be the cause, and observation tends to confirm this opinion. The minimum systolic blood pressures do appear to be low for this group. The mean frequency of occurrence of stippling in the peripheral erythrocytes of this group is not  3k - different from that of any random non-exposed group; the only two results which require comment are these of subjects #7 and 16. These results of l k and 22 per 50 fields (1,120 and l,?6o per million erythrocytes), respectively, were associated with relatively high urinary lead, and in subject 16 with some increase in blood lead. There is no good reason to believe that the stippling in these two subjects is not a response to lead absorption. There was only one subject who presented a combination of symptoms which suggested the effects of absorbed lead. This man was obviously not in the best of health, but this fact was deduced from facial expression and subjective symptoms rather than physical findings, and the subject believed that all symptoms had been present before starting this job and that there was no relation between the present job and symptoms. - 35 - This man had been employed on the job for six weeks when first seen, and had worked as a welder for three previous years in a manufacturing plant. He had a mild familial asthma. He had pain frequently in the right lower abdomen and constipation. He dreamed excessively and attributed the dreaming to eating before going to bed. He had arthralgia of the left knee joint, attributed to working position. He had headaches, and tired out easily. He had slightly irregular pupils and they were at times slightly unequal. The mean con centration of load in the urine of this man was O.I36 mg, per liter (33 samples), and the blood lead (2 samples) was O.Olj.5 and 0.055 respectively. The urine lead concentration was in the vicinity of 0 .20 mg. or more per liter on sixteen occasions, and in excess of 0 .2 5 mg. per liter on three occasions, reaching a maximum of 0 .3^ mg. on two occasions. The hemoglobin K 00 C0 310 36 - was not lowered and the examination of four blood films revealed no 3tippled erythrocytes. It is quite unlikely that these symptoms were due to lead absorption. The examiner did not consider them as such on clinical grounds, and, despite the high levels of urinary lead concentration, which may well have been due in part to low water output, lead intoxication has not been found to occur under conditions associated with concentrations of lead in the blood within the range indicated. Conclusions It has been shown that a relatively small group of workmen engage with any regularity in work involving tlie cleaning and repairing of small tanks, and that about half of these men appear to be engaged in the work quite sporadically and are occupied only from 1 to IcTper cent of their time at this work. The K t 00063.17 - 37 - remaining hair spend a greater* proportion of their time in cleaning and repairing small tank3, but over any con siderable time (months) will spend a maximum of about l/3 of their time on the repair of small tanks which have contained leaded gasoline. Analysis of the time spent at jobs which might con stitute an exposure to organic lead and estimation of the probable concentrtion of lead in the atmosphere within tanks to which these men might bo exposed shows that these com bined factors would be expected to induce neither an acute, rapidly developed lead intoxication nor an accumulation of sufficient lead over a long period of time to account for an insidious illness. The concentrations of lead in urine of these men show that, as a group, they are subjected to occupational exposure to lead, since mean concentrations for individuals (with rare exception), for the crews, and for the entire group of men }( 0 o i)h o x 8 exceed those found in the general population Blood samples were not obtained with sufficient frequency to be cf any value in supplementing the urinary findings, but they disclosed a moderate trend upward from normal levels; at least three of the men showed elevations in the blood concentration consistent with those in the Mo correlation can be sho?:n between specific job and lead concentrt ion in either urine or blood, 'out inspection of the individual results and consideration of the time spent at any possible organic lead exposure suggests that paint burning was the largest source cf the lead absorbed by these men. Nothing in the physical findings, symptoms, or laboratory findings (exclusive of lead analytical results) indicates that these men generally are being damaged by the exposure to lead which characterizes their Q0 0 6 8 19 39 - work. One man in the group nay be regarded as a possible exception to the rule, but clinical judgment would not interpret the combination of symptoms and laboratory findings in the one instance as indicative of lead intoxication. Recommendat ions This investigation should be continued as opportunity arises, because it is believed that additional useful material can be found for stud:/ and that closer attention to job-time data and the individual habits of workmen may produce clearer evidence of the source of the lead to which these men are exposed. More frequent blood sampling may also be helpful. ' Additional analytical data on the lead in the atmosphere of 3mall tanks, as a means of detecting maximal conditions of exposure, would augment the available evidence to great advantage. Determinations of the lead concentration in some of the large tanka, especially of those which would appear to be particularly dangerous, would be helpful in comparing the relative hazards of the two classes of tanks. ' 'Chile the experience of this survey is limited, :he evidence gained, e embined with knowledge of experienced contractors as to working factors, ndicates with reasonable certainty that tills work can >rcceed safely without immediate supervision. Cur position must, however, be made clear to both those who are involved in the cleaning and repair of small tanks and also to the competing distributor of anti knock fluid containing tetraethyl lead, before abandonment of supervision is accomplished. It is recommended that all tank repair agencies be informed by personal contact and publication that our position is unchanged, in so far as -recommendations H E 0006321 for the safe conduct of small tank repair nork is :cneerned, and that study has shown that these ocedures are not free from lead hazard, but that the former policy cf attendance at jobs involving entrance into small tanks i.3 being abandoned because under the present regimen of precautions, no significant hazard is believed to exist. K 0 0 0 6 S 22 Table 1 Total Length of Time Spent by Workmen in the Performance of Various Designated Jobs During the period of the Observations. Together With"the Mean Concentrations of Lead In the Urine and Blood of Individual Workmen brieran Hours urr.her At 7T Hours At i-*^>4 '*fv *y*<? \L. it Total Hours l2 f3 ,ij. Lead In Urine Lean Observed Period Lead1 in Blood lean .-if-.;./ioo g. (Dithizone) x h - 2 20.4 18 .0 38.lt 0 .0 63 8- 17-48 9- 15-48 0 .0 45 0 .0 60 r> 1.3 17.1 4.3 21.4 0.121 8- 23-48 9- 8-48 0.05 0 .0 4 J 2.9 94-0 9 6 .9 4- 1.7 6.0 6 .0 -N 1.8 7iuA 7.6 o 1.6 i5.o 15.0 *7 i 0.4 5.6 109.3 lliv.9 8 2 .4 10.2 30.5 I4.O. 7 a 2.5 !i-.6 LJ4..I4. 49 *o 10 1.8 9 22.3 2 7.2 1i 3.7 4.6 34*6 39.2 12 0.4 0 .4 13 o.i*. 55.3 55.7 4 0.4 0 .4 0 .4 15 5.5 19 .8 35.il- 55.2 16 0 .4 1.9 U-5*6 47.5 1? o.3 4.8 0 4.8 0.102 0 .13 6 0.163 0 .114 0.220 0.081 0.115 0.117 O.I36 0.103 0 .10 0 .0 67 0 .13 2 0 .113 0 .0 63 8-17-48 9-15-48 8- 17-48 9- 15-48 10- 6-48 0 .0 60 0 .0 75 0 .0 5 0 .0 55 0 .0 4 10- 7-48 1-11-4 9 1-11-49 / 0 .0 35 0 .0 6 0 .0 5 1-17-49 3-16 -4 9 1-10 -4 9 3-16-49 1-10-49 3-16-49 2- 8-50 2-2 2 - 5 0 3- 3-50 3-11-50 3- 21-50 4 - 5-5o 4 -12 -50 3 -2 1-50 3- 28-50 4- 5-5o 0 .0 5 0.05 0 .0 3 0 .0 5 0 .0 4 0 .0 4 0 .0 5 0 .0 65 0 .0 7 0 .0 7 0 .0 8 0 .0 65 0 .0 6 0 .0 6 0 .0 3 0 .0 4 Table 1 - Continued '.Workman .umber Pours At H 13 3.3 Hours At k.k Hours At S 2 .0 Total Hours 6 ,1^. Lead in Urine Mean Observed Period bI&./L. Lead in Blood Kean Mg./lOO k . 1 0 itVisone) 0.057 3-21-50 3- 28-50 4-- 5 - 5 0 1.-12 - 5 0 0.065 0.055 0 .0 4. 0 .0 ^ Totals (Hours) Average Time Por Entire Period (Pours) Average Time Per Lay Per Han (Hours) - 2 .0 8 6 O.0 8 3 Total Ti^np 13 1.0 7.2 78 0 .2 9 1 1 ij-95.7 ^1.3 0 8 1.6 5 2 Total 626.7 3 i|..8 l6 1.393 ^Job Identification 1. Tank Cleaning 2. Sludge Handling (Outside Tank) 3. Paint Burning . ij.. Inside Y/elding H E 000(35^4 Table 2 Conditions of Exposure Concentrations of Lead in the Atmosphere Within Storage Tanks Repaired by Crew ??1 Mg. Lead Per 10 Cubic Meters Tank# Identification Before Cleaning During Cleaning or Immediately After Later Buch 6 No Sampling Gob 1A .. o-k... liul 7 Gob IB 0 liul 10.5 31 2 0 n1 5.2 ScH 3 7 7 7 ?en I; llj-.l 12.lt 10 .5 Mus Hdt 2A Cas 2 3 ,$ 3'.6 1.0 7 10 .5 h.2 5.3 l.k 7 Mid 3 10 .5 liul llul Average it.8 10 .0 7.6 *?ank identified by town abbreviation and tank number. Later 2.1 10.5 7 6.5 f! k r o0 Go o o Table 3 Conditions of Exposure Concentrtions of Lead in the Atmosphere Within Storage Tanks Repaired by Crew #2 Kg. Lead Per 10 Cubic lietera Tank* Tdentification Before Cleaning During Cleaning or Immediately After Later Ab 111. 'on Oq B1 Car Tush Tush Tear Bar Sas Or ret Average 1 0.7 Ii 2.8 2 !l.2 2 0.7 3 2.1 * 5.6 h .. .... 3 o . It . . i ..... 2 Ii.2 1 0.5 3B 2.8 ? l.It 2.It lli.l 10.5 II.2 2.8 2.8 10.5 II.2 l.It 7+ 2.8 7.0 0.7 5.7 7.0 5.6 3.5 5.3 7.0 5.3 3.5 6.0 7.0 - _ .1 . 2 .... _ 2.8 5.6 5.2 -:rlank identified by town abbreviation and tank number. Later i Il.i K F ooos^y Table k Conditions of Exposure Concentrations of Lead in the Atmosphere Within Storage Tanks Repaired by Crew #3 Mg. Lead Per 10 Cubic Meters Tank ident ificat ion Before Cle3-iix ng During Cleaning or Issnedlately After Later Later 5art Ind. 1 Muff ks iec 3C !lay 3 r* . 2 .. . IS ,'ar L 10.5 ld.l 2.1 0.7 l.k 10.5 lk. 1 k.2 k.2 5.6 7.0 7.0 2.8 k.2 2.1 5.6 ar 3 Resiilte Questionable .verage 5.0 7.7 _____b d _____ -Tank Identified by town abbreviation and tank number. 2.8 2.1 2.5 Note ; Crew k did not work on any leaded tanks. 00068^7 Tank 5 Conditions of Exposure Concentrations of Lead in the Atmosphere Within Storage Tanks Repaired by Crew #5 Mg. Lead Per 10 Cubic Meters Tank* Identifieatdon Before Cleaning During Cleaning or Immediately After Later Later Later Srrp Fowl Fowl Fowl Fowl -ell 'ell Fall Lit Mel Ros Ros Ala Ala Ala Ala Ala Pitch MidIdle / r\ -P ' S T_ o mm 1 2 1 i 1 3 2 1.1}. 0.? 7 t* . 7 i.i 0.7 0 0 O.ii 0 lu 3 0.7 8.5 0 lu 2 3.Il l.lt o.k 1.1 3.2 l.lj. 0 2.1 1.1 1.1 5.7 22.6 2.8 0 6.1}. lu 2 0.7 0.1}. l.ll7.1 -1.2.. . O.k 0.7 O.k 1.1 8.5 _.. 2.9 0.7 l.h. `0 2.1 1.1 1.1 1.1 0 0 1.8 l.lj. l.l 1.8 ... l.ll-... .. . 1.1 0 0 0 O 8 ki8 Table 5 - Continued Tank [dent ification Before Cleaning During Cleaning or Immediately After Later 3el 4-69.. l4.9 ;Ol -1-1''741,.. . d-3 tel 177!ii-i. 11.3 7.1 2.5 ... 1-k :el I17it del 117k avrs>*a o 2.2 k.2 2.0 -frank identified by tovm abbreviation and tank number. Later Later 7.1 l.k 0.7 1.5 _____h k ___ K & ooaookj CM 1CM fn Table 6 Conditions of Exposure Concentrt ions of Lead in the Atmosphere Within Storage Tanks Repaired by Crew #6 Sag* Lead fer 10 Cubic Meters Date Tank* Identificati on Before Cleaning During Cleaning or Immediately After 3-20 r\*v *'T-v iXX. n C . mmmmrnm. 1 0.7 ' ar 0.7 3-23 El 2 5.3 3-5 3-27 '.Vil 2 ___ 4.3..... 4.3 3-30 ii 2 1.8 5.3 4- 2 .. Gli 4- 4 r.ll An 4 3.5 s. J p g 2.S 2.1 4.3 3.5 4-14 Ar 2 3.5 2.1 4-i6 don 2 4.2 3*5 Average 3.3 3.3 Tank identified by town abbrev iat1on and tank number. Later 1.4 1.8 2.8 . 2.8 1.4 1.1 2.1 2.8 0.4 2.1 . 1.9 K B 0006330 Table 7 Small Tank Survey Individual Results Mg. Lead Per Liter of Urine Crew -/I Pruitt Jenes Allee Ilsuhaus irl #2 % Pruitt's Crew - Results Kean Error 0 .0O2500 + 0 .0 0 2221 0 .120 8 8 2 7 0.005250 -.101795 7 O.ccii.958 0 .1363614.7 0 .0 0 9767 0.1C27lt0 + 0 .00338)4. Crew 772 Sandefur Skeen Jilnite 'illcr 0 in 68 Sat;dofur 5s 0row - Results . 0 .16 2 8 57 + 0 .0 0 6919 O . H 3718 7 0.C03711 0 .220 29)4. + 0 .0 34692 0 .081)^29 t 0 .00)4.189 O.ltoSl i 0.005590 Crew j/3 -.orton *'r*f\v*sn t>tt Paxter #9 J10 ,'11 Baxter's Crew - Results 0 .115 10 5 0 .007)1.0)4. 0.117333 7 0 .00)4.821 0.135517 7 0.005917 0 .12 2 79 1 +. 0 .0 0 3 6 11 -C-row ~!f Ui Irnore Russell Oallirnore '12 13 nk Gilrore's Crew - Results O.O93I4.92 + 0.002751 0 .119 )4.55 T 0 .0 0 6 155 0.07354-8 7 0 .0 0 3235 0 .09)1.556 + 0 .0 0 2563 . Grew 5 Schneider #15 0 .13 2 2 73 + 0 .0 0 76 12 Crev/ 776 Drain Chicks Vogler 16 7717 # 18 Drains 's Crew - Results 0 .113 13 7 + 0 .005)4.6)4. 0.063000 + 0.003083 0 .0 573)4-0 7 0 .0 0 30 32 0 .0 78 951 + 0.0 0 280 7 0 0 c*> /T, CO Ck-> Table 8 Temperature, Pulse Rate, Blood Pressure, Hemoglobin, and 'tippieci ell flanges Subject Number Temperature Pulse Blood Pressure Hemoglobin 1 98.0 - 99.0 76 - 8 i| 118 - 13 6 15.0 - 15.5 32 - 9 ^ 2 98.0 - 9 8 .k 76 - 92 10 0 - 115 15.5 - 16 . 0 7- - 30 3 97.3 - 9 8 .6 6 If - 8I4. 100 - 120 1 5 . 5 - 1 5.5 68 -- 80 b. 9 8 .2 - 9 8 .6 70 - 82 110 - 120 15.5 - 17.0 60 - 80 p 9 8 .0 - 9 8 .6 72 - Gii. 110 - 128 15 . 0 - 15.5 70 - 80 Ur 9 0 .6 - 9 9 .0 72 - 10 0 n!i - 12 5 15 . 0 - 15.5 6k - 70 l 0 - yu.O 66 - 76 10 0 - 112 Ik.5 - 15.75 6k - 75 G uy 9 8 .6 96 lk.o - iii.,5 13 0 1 6 . 5 70 10 93^6 76 12 6 62 16.5 il - ::o physical examination - daily urinary samples obtained. 12 9 8 .2 - 10 0 72 - eli. lilt - 13|j. 15.75 - 16 . 0 6 2 7!). 13 9 8 .0 - 9 9 .k 60 - 92 100 - 110 15.5 - 17.0 6k 714 - Ik 9 8 .0 - 9 8 .6 80 -10 0 100 - 120 15.5 - 16.5 80 - 80 15 9 8 .6 80 125/90 1 5 .0 16 9 8 -I4. 70 116 / 8 0 15.5 17 99.0 70 I I 4.O/ I OO 15.5 18 99.6 10 6 10/100 12.25 Stippled '"""ells 0 1 6 0 0 0 ik 0 0 0 0 1 0 0 22 5 1 K g ' 00fli5832