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REPORT ON A N INDUSTRIAL HYGIENE SURVEY OS* E A S T E R N A IR L IN E S H A NG AR, MIAM I, FL O R ID A A su rvey of working conditions and person n el in a large hangar of a co m m ercial air transportation se r v ic e , located in M iam i, F lorid a, was ca rried out to determ ine w hether hazards or potential hazards to health ex isted in rela tio n to the u se o f aviation g a so lin e that contains up to 4 .5 m l. of tetraeth yl lead per A m erican gallon and in connection with the operations concerned with the m aintenance, fu eling, rep airing and overhauling of a ircra ft engines and fu el tanks. D escription of Subjects and O ccupations The subjects of this survey num bered 199 workm en and com prised two m ajor groups which w ere c la ssifie d in the follow ing m anner: I. E xposed Group (121) A . M otor Shop The m echanics engaged in overhauling aircraft engines carry on th eir a ctiv ities at a ll tim es in sid e la rg e, clean adequately ventilated and w ell ligh ted sh op s, with the exception of th o se o f th e engine testin g group, who m ay be req uired to w ork ou tsid e th e hangar for sh ort p eriod s in testin g ^ engines. The m ajor work inside the hangar con sists of disassem bling en- g in es, rem oving cow ling a c c e sso r ie s and tubing, cleaning engine p a rts, m aking n e c essa ry rep a irs, reassem b lin g engine parts and a c c e s so r ie s. and in stallin g the engine on te st stands. N9607 The individuals of th is group m ay com e in contact with resid u es of 2. The te st group have additional exposure to dust from the p rop eller b last, and to variable concentrations of fum es from the com bustion of gasoline and oil. B . M aintenance D epartm ent 1. Engine S ervice M echanics 2 . Line Crew 3. A ircra ft M aintenance Crew 4. Truck D rivers With th e excep tion of the tru ck d r iv e r s , who w ork in sid e and o u tsid e under a ll of the w eather conditions of the M iam i a rea , and are exposed to gasolin e and its products of com bustion when driving trucks from the hangar to the runways to d eliv er fuel and oil to airp lan es, th ese groups work in sid e and outsid e and a r e exposed to shop d irt, g r e a se , o il and g a so lin e, and to the vapors of g asolin e, o il, paint solven ts and solven t clea n ers. They are required to m ake n e c essa ry rep a irs, rep lacem ents of p a rts, and adjustm ents on en gin es, to change en gin es, if n e c e ssa r y , and to te st engines. The lin es and m aintenance crew s are a lso subjected to n oise and vibration in testin g en gin es, and they are ca lled upon frequently to m ake m inor rep a irs to fuel lin es and tanks and to r e se a l breaks in the lining of fu el tan k s. In ca rry in g out th is la tter job , the tank p la tes are rem oved , and after ventilating the tank fo r ten m inutes by m eans of an a ir blow er, gasolin e resid u es are mopped up from the bottom of the tank, and the rep air and sealing of the lining are com pleted. The sealin g operation requires the use of solvents such as m ethyl ethyl ketone, m ethyl acetate, 3. m eth ylen e chloride and v a r so l, as w ell a s "Stabond, " a sea lin g com pound. It is u su a lly n e c e ssa r y lo r a w orkm en to sta y in the tank fo r periods ranging from 10 to 30 m in u tes a t a tim e , and se v e r a l such e n tr ie s m ay be m a d e du rin g th e c o u r s e o f th e day* s w o rk . C. Plane Overhaul Shops R ep a ir of Wing Tanks M em bers of a group of fou r m echanics are rotated in th is w ork, each w orking one w eek in ev ery m onth. Tank en tires for each workman usually range from 1 to 3 per 8-hour w orking day and total about 30 en tries per m onth. The procedure for this job m ay be d escribed b riefly as follow s: The m anhole s tr e s s plates are rem oved from the w ings, and the tanks are a ired fo r 12 to 14 hours by m ean s of an a ir h o se and fan . A fter th is in terval a forem an en ters the tank to m op up resid u al gasolin e and check for rep a irs. M echanics then clean the lining su rfa ces at the site of dam age with solven ts } and apply appropriate sealin g com pounds. Continuous a ir flow from a blow er and fan is m aintained w hile the m en are working in the tank. A p o sitiv e -p re ssu re type of h ose m ask is available for u se in any unusual situation or em ergency. It is not used routinely because vapors are not p resen t ord in arily after the tank has been drained and aired . In addition to the opportunity fo r exp osu re to vapors from g a so lin e , s o lv e n ts and s e a l e r s , th e r e e x is t s a ls o th e p o s s ib ilit y of cu ta n eo u s and resp ira to ry exp osu re to dust arising; from the pow dery d ep osits on the sid es and bottom of the tank. This sed im en t is p artially rem oved by w iping the su rfaces with a dam p cloth , but b eca u se o f the projecting stru ts, KE 4. th ese su rfaces are difficult to clean thoroughly in this m anner. T h e s e w o r k m e n w e r e p la c e d in a ''S p e c ia lly E x p o se d G roup" in th e ta b u la tio n o f the data in o r d e r to d eterm in e m o re r e a d ily w hether g r e a te r opportunity for exposure to lead existed under th ese conditions. II. C ontrol Group (78) A . Plane Overhaul Departm ent 1. Sh eet M etal W orkers 2. A ircraft A c ce sso r y M echanics 3. W elders 4. diggers T hese m en work in sid e and outsid e under a ll w eather conditions and a re ex p o sed to d u st in the a tm o sp h ere and to va p o rs fro m paint paint so lv e n ts and cleaning flu id s. They are required to m anufacture new p arts, m aintain and repair structural p arts, heating and ventilating sy ste m s, and to in stall w ings, controls and rudder pedals. B . M otor Shop 1. E lectricians 2. M achine Shop M echanics Both of th ese groups w ork in sid e at a ll tim es in w ell lighted and w ell ventilated shops. The electricia n s are required to rem ove, rep air and in sta ll electrica l appliances on the engine mount a ssem b ly . They a re subject to e lec tr ic shock in carrying out testing procedures. The shop m echanics a re exposed to dust and d irt. They are required to operate punch p r e sse s, lathes and other m achine tools in the m anufacture and rep air of m etal parts and equipm ent. ,, ...... METHOD OF SURVEY The data of a com prehensive clin ical study of each workm an w ere r e c o r d e d on fo r m s d e ta ile d in F ig u r e s 1 2 and 3. The h isto ry {Figure 1) included the u su al m ed ica l inform ation* as w ell as a detailed occupational h isto ry , sp ecia l em ph asis being placed on the d eter m ination of the nature and degree of exposure to lead in any m anner, and the tim e at which such exposure had occu rred . The p h ysical exam ination w as d etailed and d ealt with a ll of the sy ste m s of the body (F igure 2). V isual te s ts w ere m ade with the K eystone instrum en t. O ther exam inations included X -ray of the ch est, electrocard iogram and com prehensive laboratory in vestigation s (F igure 3), including sero lo g ic ex a m in a tio n o th e b lood *, e r y th r o c y te , le u c o c y te and d iffe r e n tia l blood co u n ts, hem oglobin estim ation {Spencer hem oglobinom eter), enum eration of the eryth rocytes containing basophilic granules (stippling), and u rin a ly sis. The lead content of the sam p les of blood and urine was determ ined. E xtensive experience over a num ber of years has dem onstrated the reliab ility and sig n ifica n ce of the r esu lts of a proced ure by w hich sm a ll (40 to 200 m i .) or "spot" sa m p les of urine are co llected in ch em ica lly clean b ottles with latex caps and analysed for th eir lead content. Standards have been established, on the b a sis of th is exp erien ce, for determ ining the norm al range of values and for c la ssify in g variou s groups of ind ividu als with r e sp e c t to the extent of th eir lead absorption. (This can be done for the individual only on the b a sis of the % analytical inform ation obtainable from a su fficien t num ber of sam p les of sm a ll volum e.) The sign ifican ce of the le v e ls of concentration of lead in the blood has a lso been defined with referen ce to the range of norm al valu es and of th ose a sso cia ted with varying d e g r ee s of exp osu re to lea d , including th o se which rep resen t hazardous exp osu re. The p r e c ise point of differentiation betw een the h igh est concentration in the blood of an individual which is safe ( i.e . unattended by any likelihood of hia developing any sig n s of lead intoxication) and the lo w est which is dangerous ( i.e . a sso cia ted w ith a low incid en ce of m ild intoxication) cannot be fixed with absolute certain ty, if for no other reason than that th ere is an an alytical err o r in trin sic in a ll m ethods of a n a ly sis, which cre a te s a narrow range rather than a point fo r the th resh old valu e. On the b a sis of the analytical m ethods em ployed in th is L aboratory, this range can b est be d escrib ed as 0 .0 7 5 m g. to 0 .0 3 5 m g . of lead per 100 gram s of whole blood. Since th is is w ell beyond the range of the resu lts encountered, it need not be referred to again, except a s a point fo r referen ce. The findings on duplicate sam p les of blood are m ost u sefu l in conjunction with th ose obtained on sam p les of urine. F rom the exam ination of th ese com bined data on ind i viduals and groups of m en, it is p o ssib le to recogn ize the occu rren ce of occupational lead exposure on the part of the individual o r w ithin the group, ana to app raise its sign ifican ce without question. In th e r e la tiv e ly few in s ta n c e s in w hich a b n o r m a litie s w e r e en co u n tered in the su b jective and ob jective fin din gs, lab oratory data, electro ca rd io g ra m s, or X -ra y film s of the ch est, the c lin ica i a sp ects of the c a se w ere d iscu ssed with the individual workm an for the purpose o f giving helpful advice fo r the sp ecific ailm ent, a s w ell as for utilizing the inform ation as part of the o v er a ll investigation. On the com pletion of a ll of the exam inations, the data w ere tabulated and r ev ie w e d . Eac^ c a se w as studied a s a u n it, and the v a rio u s groups w ere 7, are record ed in Table 3. T ables 4 and 5 illu stra te the range of concentration of lead in sam ples of blood and urine for both the exposed and control groups of w ork ers. S tatistical evaluation does not reveal any significan t difference betw een th ese groups, and indicates that the exposed w orkers have not absorbed am ounts of lead that have approached or exceeded the upper lim its of safety. Table 6 show s the values for lead in the blood and urine of individuals without ex p o su re, as w ell a s of groups of m an su b jected to v ariou s edtncerairations of lead in th eir workihg^environm ent, taken from reports of previous in v estig a tio n s. It d e m o n str a te s the s im ila r ity b etw een the ex p o su re of m e c h a n ic s, m ain ten a n ce workers and repairm en of a com m ercial airlin e and that of fillin g station attendants and autom otive m ech an ics. Exam ination of th ese data in th eir en tirety failed to d isc lo se any analytical evidence of h ygienically significant lead absorption of any relevant clin ica l evidence of such absorption. aamma vy This com prehensive investigation of the likelihood of hazardous exposure in r e la tio n to th e u s e of a v ia tio n g a s o lin e that co n ta in s up to 4 . 5 ml. of te tr a e th y l 30 * lead com pound per A m erica n gallon to tetraeth yl lead an d /or its degradation 05 products on the part of m echanics and m aintenance crew s engaged in servicin g O and repairing airplan es, aircraft fuel tanks and engines com p rises a survey of 121 te s t and 78 con trol w o rk ers, and iai^s to d is c lo s e the o ccu rren ce of s ig n i fica n t exp osu re to lead . On the b a sis of th ese findings th ere is no ind ication 3. that m aintenance crew s and airplane m echanics have an opportunity for the absorption of sign ifican t am ounts of lead eith er through contact with aviation gasolin e or from exposure to the sedim ent or resid u es of aviation fu el that h ave b een d ep o sited on engine p arts and on the lin in g o fu el tanks. P rom The K ettering L aboratory in the D epartm ent of P reven tive M edicine and Industrial H ealth, C ollege of M edicine, U n iversity of C incinnati, C incinnati, Ohio ' Survey by: M edical E xam inations Howard K. Edwards, M, D. M edical Departm ent E astern A ir Lines M iam i, F lorid a John Lauer, M .D . Lu. . ochradin, hf.L# K. V. K itzm iller, M. D. T echnical A ssista n ce C lara Keenan Dan D uvall A nalytical Data Jacob Cholak S ta tistica l Study E stelle M ergard Report by: K. V. K itam iller, M .D . A pproved: Robert A . Kehoe, M. D. Kj r 00Go030 Table 1 D istribution of Subjects A ccording to Subjective A bnorm alities Subjective A bnorm alities specially Exposed E x p o s e< G roup Group Number P er Cent dumber P er Cent 109 12 Control Group N um ber |Per Cent 78 W eakness 1 0 .9 D row siness Insom nia ;2 1 .8 D isturbing D ream s j1 0 .9 Headache .M , Ye r t ig o , M, Indigestion A norexia j{jj 9 L 8 .3 jj 1 :4 3 .7 9 8*3 2 16.7 2 16.7 3 3.8 15 1 9 .2 2 2.6 M etallic T aste ' Abdom inal Pain ]1 0 .9 2 2 .6 N ausea |{ 1 0 .9 2 2.6 Vom iting D iarrhea C onstipation 8 7 .3 s . 7 .7 Table 1 (Continued) D istribution of Subjects A ccording to Subjective A bnorm alities Subjective A bnorm alities Specially Exposed E xposed Group Group . Number *er Cent Number P e r Cent 109 12 Control Group N u m b er lp er C ent 78 R ecent W eight L oss M uscle W eakness M uscle T rem or M uscle Cram ps Painful E xtrem ities Num bness T in g lin g L oss of Sensation A bdom inal Pain Chest Pain D ysp nea Joint Pains C old s, Sinus* Masai A llerg y 1 j1 j 2 2 , J 20 0. 9 0 .9 1 .8 1 .8 1 .8 18. 3 1 8. 3 4 33.4 1 1.3 1 1.3 3 3.8 6 7.7 19 2 4 .4 K ^ 0 u if Oij Table 2 D istrib u tion o f Subjects A ccordin g to O bjective A b n orm alities 1' O bjective A bnorm alities j E xposed Group Specially Exposed j Group Number .P er Cent Num ber p e r Cent 109 12 | Control Group dumber p er Cent 78 l P allor A nxious E xpression '.Veight L o s s e f 1 1 0 .9 0. 9 1 | 8.3 1 L 8 * 3....... .......... 1 1. 3 Tem p, E lev. (Above 9 9 .6 * F . } 5 j 4 .6 4 5. 1 Tem p. Dep. (Below 9 7 .4 *F. ) T achycardia (100) B radycardia (60) 3 2 .8 ; 7 6 .4 7 6.4 2 2.6 3 10* 3 1 1.3 G. E. Tract 1 1.3 .Lead L ine Extensor W eakness 1 1.3 Sensory D isturbance C ardiac L esion 1 0 .9 1 1 .3 Pulm onary L esion He rnia 1 0 .9 t 1.3 ^,1 Pk \pji \bJ r\$. ^.1 ,,v3--i -i Table 2 (Continued) D istribution of Subjects A ccording to O bjective A bnorm alities O bjective A bnorm alities Specially Exposed Exposec Group Group Number P er Cent Num ber P er Cent ~ 109 ~ 72 Control Group Number P er Cent 78 Spine .Lesion 1 1.3 Lymph Adenopathy 9 8. 3 V aricose V eins 4 i 3 3 .7 2 .8 1 1.3 3 3.8 Abnorm al R eflexes Skin L esion N ose and Throat F in d in g s 5 2.3 iO 9 .2 2 .6 2 2.6 Renal C olic (Stone) Psychopathic P e r so n a lity 1 0 .9 : ! 1 O' o A nxiety State P rostatitis 2 1.8 2- i . 8 V aricocele H em orrhoids Bell* 3 P a lsy (R esidual) 4 3.7 2 1.8 1 0. 9 1 [ 1 l t 1. 3 I S 1. 3 wn o' o>'d'' Table 3 C om parison of the Mean V alues of V arious A ttributes of the Groups E xposed Group (109) S p ecially E xposed Group (12) ; Contr C lassification. P er Cent M ean, P . E. , St. Dev. P er Cent Mean, P .E ., St. D ev. P er Cen of Group of Group of Group A g e ................ . E ryth rocytes 7^ 106/m r n . 3 TE\ H em oglob in o ^Spencer} g . /100 c. c. L eu co cy tes 103/m m . 3 cc or 100 100 100 ;o0 !. 34.372 0.674 " 10.438 5099.082 26.173 405.128 16,255 0.056 * 0.865 6701.834 129.735 2008.150' AGO .100 100 100 32.667 1.319 x 6.774 5075.000 65.125 334.477 16 .1 2 5 0. 098 0.505 6708.334 378.009 X 1941.415 100 100 100 100 Table 4 C oncentration of Lead in U rine of M en Em ployed by a C om m ercial A irlin e Lead Mg. /L . F requencies of O ccurrence of Q uantities of Lead Indicated E xp osed Group Sp ecially E xposed Group Control Group 0 .0 2 - 0. 029 23 4 0 .0 3 - 039 0.04 - 0.049 20 )1 i 1 0.05 - e.0 5 9 ! 19 1 0.06 - 0 .0 6 9 0.07 - 0.079 \ 1 0.0 3 - 0.039 }. 1 3 6 1 ! 1 2 i | i 1 < 0 .0 9 - 0.099 0 .10 - 3. 109 0.11 - 0. 119 . .............. '_________ j._________ 0............... ............... I 5i 0 T0 0.12 - 0.129 0 1 0 .1 3 - 0. 139 o o T o ta l M ean 107 0 .0 5 2 i xZ 0 .0 5 5 | Probable E rror 0.002 0.006 Standard D eviation 0. 024 j 0. 030 34 16 3 9 6 3 3 ] 49. 0 0 l rK.-- *f n</ . cV- a w"* i: 0.002 0.023 'E 0 0 Go 0 y b Tabla 5 C on cen tration o L ead in B lood of M en E m p loyed by a C o m m e r cia l A ir lin e Lead jj .F r e q u e n c ie s o f O c c u r r e n c e o f Q u a n titie s o f L ea d In d ica ted Mg. /1 00 g. W hole Blood E xposed Group S p ecia lly E xposed Group C ontrol Group 0.020 - 0.024 12 0 12 0. 025 - 0 .0 2 9 i________ i . ________1 0 .0 3 0 - C. 034 1 vi 0.035 - 0.039 1 24 26 2 2 J*9 3 16 ! is 0.040 - 0.044 i 1 0.045 - 0.049 ! 0.050 - 0.054 I it 0.055 - 0.059 I ' " 1 7 8 1 " J............ _1 3 "----- ------- ------ 1 1 ! .r ' i 0j 15 5 8 0 0.060 - 0.064 S 0' ' T o ta l M ean i 109 ?................... 1' I 0.036 ! Probable Erro 1 i Standard D eviation a 0 .0 0 1 0 .0 0 9 0 0. 038 0 .0 0 1 0 .0 0 7 j1 1 ________ 7 8 ............. ! 0.037 i j .001 1 0.009 , \/MJ Table 6 t . ,\r ?'y.f a` - i-" V-U- ' TX'm.'-' ' \ ^ .. 5LW - The C oncentration of Lead in the Urine and B lood of Groups of P erson s W ithout Known E xposure to Lead and of O thers Subjected to V arious D egrees and Types of A ctual and Suspected E xposure to Lead U rin e Mg. /L . No occupational exposure 0.01 - 0.08 Garage M echanics 0.04 - 0.10 Paint M anufacture 0.08 - 0.12 W hite L ead M anufacture (H azardous) 0.14 - 0.18 Lead Sm elting (Hazardous) 0.18 - 0.22 O ccupational Exposure R esulting in C ases of Lead Poisoning 0.24 - 0.96 M ean V alues G a ra g e M e c h a n ic s ~ 1943 (12) *" 0. 058 G arage M ech an ics - 1949 (8) 0.072 G arage M echanics - 1949 (12) 0.106 F illin g Station Attendants and W arehousem en - 1949 (52) 0.073 Engine M echanics, M aintenance Men, Overhaul and R epair M en C om m ercial A irline E xposed Group (109) 0.052 S p ecially E xposed Group (12) 0.055 C ontrol Group (78) 0.042 B lo o d M g. / 100 Cm, 0.01 - 0.06 0.039 0.04 0.08 0. 15 0 . 1 5 - 0. 30 M ean V alues 0. 043 0. 035 0.051 0.041 0.036 0.037 0.037 f 0 0 u Aa * (S