Document 1yjzwB878JOxRJzvZoDybY5EK

FILE NAME: Maryland Casualty Company (MCC) DATE: 1965 Jan 27 DOC#: MCC002 DOCUMENT DESCRIPTION: Letter to MCC Medical Director from Univ of MD School of Medicine with Recommendations RE Zonolite UNIVERSITY OF MARYLAND SCHOOL o r MKdCJNK OIVIUOM rod rULMONAKY DUKASES lAUWOU 1. MASYkAMS January 27, 1965 R obert F . Chenowith, M. D. M odical D irector M aryland Casualty Company B altim ore, M aryland 21203 D ear D octor Chenowith: We have com pleted our review of the group of record of the em ployees of the G race Company who are a sso cia ted w ith the ZO NO UTE operation in north* w estern Montana. I have chosen to approach this from the point o f view that the G race C om pany i s d e sir o u s of m ain tain in g th is o p e r a tio n w h ile a s s u r in g befo th e m s e lv e s * and their em ployees of the sm a llest p ossib le r isk of health hazard from the develop m ent of pulm onary a sb esto sis. You w ill find enclosed the origin al reco rd s plus: 1. A brief su m m a ry o f the lite r a tu r e . 2. An analysis of the health reco rd s. 3. An outline for an epidem iological study of the effects of this industrial hazard. I would sum m arize our thoughts and recom m endations in the-follow ing . .w a y . I h a v e aotBShg but the h ig h e st r e s p e c t fo r D r. N e lso n in undertakingt h i s , study w hile carrying on a busy p ra ctice. However: he su ffers from a lack, of etjTHpmsne ah u petrsonnsi need eh t o - p e n o r m am a d eq u a re e v a iu su u n r w h ile m a n y o f th e r e c o r d s a re u n sa tisfa c to r y , a p lu s 20% x - r a y in c id e n c e o f p u lm o n a ry infiltrate plus som e confirm atory ph ysiologic evidence would suggest that this plant has an im portant health problem . T his is p articu larly so, a s resp iratory function te s ts of the type he perform ed a re aim ed p r im a r ily at elicitin g o b stru ctiv e airw & yd isease while pulm onary a sb e sto sis is p rim arily a fib ro sis or r estrictiv e d ise a se . In other w ords, should m ore sen sitiv e te s ts , i. e . , diffusing capacity, lung com pliance, work of breathing, a r te ria l blood g a ses and ventilation at r e st and e x e r c is e , and total lung volu m es and airw ay conductance be applied T w ould * n o t be su rp rised by a doubling of th is in cid en ce of d is e a se . A second point to note is that in any group of w orkers such as this w here a m ajority are cigarette s m o k e r s one can ex p ect to find a p r e v a le n c e o f 20% o r g r e a te r o f o b s tr u c tiv e p u u n t !ff? E X H IB IT A Century of Democratic Opportunity in ffirh tr r 03039 Robert 7 , Cher.owilr., M. D. -2 - airw y d is e a s e on the b a s is o sm ok in g w hen s e n s it iv e t e s t s and q u e stio n n a ir e s are u tilized . The com pany cannot be held r esp o n sib le for th is d isc a so . In addition a 5-15% prevalen ce of asthm a can be exp ected in the adult population. T herefore, if the company plans to evaluate th is health problem , it shouldn't be done without the assu ran ce of a conqplete ep id em iologic and p h ysiologic w ork-up and som e care m ust be taken that in the selectio n of resp iratory function te sts one is not caught in the frequent trap of assu m in g that a few sop h isticated te s ts offer an a ssu ran ce that in the future individual w o rk ers won't be studied, p o ssib ly for legal reason s, with com plete testin g w hich w ill rev ea l d efects not previou sly shown. T h is.exact circum stance has occu rred in M aryland and I can a ssu re you that the defendants lost such c a se s , no doubt in part from th eir unwitting, failu re to obtain com plete testing in a com plete study plan at the ou tset. I would recom m end to you that a com plete epidem iologic and p h ysiologic study be done in K alispell in the near future, follow ed by the institution of w hatever dust control m easures are deem ed n ecessary and a repeat of the testing procedure in two - three y ea rs. In addition, a m atched, con trol group of w orkers not exposed to a sb esto s be studied, p ossibly from another G race Co. operation, eg. D avidson C hem ical, etc. Such a study would be co stly as it would involve m oving a team of in vestigators and equipment to K a lisp ell on two O ccasions plus the study of a control group. However, it has been m y experience that the cost of such a study v ery seldom exceed s the size of one law suit resu ltin g from in d u strially acquired d isab ility. It is p ossib le that the D iv. of O ccupational Health, U. S. P .H .S . would support such a study. It is undoubtedly an ticlim atic to note that w e have the p erson n el and experience to do such a study and I w ill be speaking to the Montana A cadem y of .G eneral P ractice this June. Should you have any further qu estion s, I w ould be happy to attem pt to A n sw er them*. S in ce r ely , -la-*7.k*-<uSj WILLIAM S. S P IC E R ,/jR ., M. D. Head, D ivision for Pulm onary D isea ses W SS:skh E n clo su re ASBESTOSIS STUDY T he fo llo w in g i s a. c u r s o r y a n a ly s is o f 140 s u b je c ts , 136 o f w h ich w ork in a s a sb esto sis plant. Four subjects are city em ployees. The inform ation available co n sists of nam e, age, height, w eight, vitalor spirom etry, chest film report, and brief work history. M ethods: Spirom etry w as obtained w ith the vitalo retracing s w ere exam ined-for technical accu racy and for- subjects cooperation and exerted effort. T hejvital capacitiesA w ere expressed as % of predicted norm al vital capacity. T hese axe classified : S = satisfactor E = exceeded 5. 0 liter s w hich is the m axim um capacity of the vitalor, and U - un satisfactory . (FEVi) The forced expired volum es in 1 second^are exp ressed a s % of predicted norm al for 1 second. T h ese and the m axim um expiratory flow r a tes (MEFR) w ere categorized: 1 = good, 2 = fair, and 3 = com pletely unsatisfactory record. The ch est film rep orts w ere graded accordin g to the a sb e sto sis cla ssifica tio n u sed by W illiam s and H ugh-Jones (1). Each lung w as divided into thirds and each a rea graded 0 -3 fo r no, slig h t, m ediu m , -and heavy m ottlin g (grading 0 -1 8 for no to e<rhr<. i u. R esults: %t uj v i R adiological Changes com patible w ith asb estosis a-Ktl n r f -f m * vt-- *--*.;* d urecrc (2-i/iW) w e r e p r e s e n t in 20. 6%Aof th e p lan t w o r k e r s: 39% (18 su b je c ts) of th e s e h a d -p le u r a l r e a c tio n , p r e su m a b ly fr o m a sb e sto sis as no case of pleural reaction w as reported in the absence of evidence of a s b e s to s is on x -r a y . The s e v e r ity of a s b e s to s is . . -pears to be r e la te d to the total duration of w ork and to the duration of w ork in the m ill (table 2). The x -r a y grading sy ste m of 0 -1 8 would c la s s ify 26 of the 28 w o rk ers w ith a s b e s to s is a s having m in im al d iso ssa (grada 1-6), 2 a* having m od erately advaacad d isease (grada 7- 12). and none as having far advanced d isea se (grada 13 -1 8 ). Sp irom etry. V ital cap acities w are co n sid ered satisfactory for an alysis in 35% of c a s e s ( 4 9 /f iO ) . T8% (25 c a s e s ) o f the r e c o r d s e x c e e d e d 5. 0 lit e r s w h ile 47% (66 r e c o r d s ) w e r e c o n s id e r e d subm axim & l fo r v a r io u s r e a s o n s . T h e r e fo r e , 65% of th e v ita l ca p a cities could not be u sed in the a n a ly sis. 60% ($ 4 r e c o r d s ) o f th e F E V ^ q" w e r e e ith e r good o r fa ir and c o n s id e r e d s a tis fa c to r y fo r a n a ly s is . T he o th er 40% w e r e e x c lu d e d fr o m the study. 62% (87 r e c o r d s ) o f th e M EFR*s w e r e e ith e r good o r fa ir and c o n sid e r e d s a tis fa c to r y fo r a n a ly s is . T h e o th er 38% w e r e e x c lu d e d fr o m th e study. The relationship s among spirom etry, x -r a y evidence of a sb esto sis and w ork h istory are seen in T ab les 1 and 2. It app ears that the FVC and M EFR values in th ose without a sb e sto sis on x -r a y are sligh tly b elow norm al. This is probably a r esu lt of subm axim al effort on the part of the su b jects. The FEV^ in th is sam e c group is within norm al lim its. R elative d ifferen ces betw een the different groups suggest m ild d ecrea ses in the v ita l aapacity, FEV1 and M EFR in those with a sb esto sis The FEV1 m ay be w orse in the m ill w orkers. No definite changes in spirom etry are - r scen with in creasin g grade of a sb esto sis how ever, the number of ca se In each group is sm all. D iscussion: T h is stu d y in d ic a te s a 20% in c id e n c e o f a s b e s t o s i s in w o r k e r s stu d ied . Crude spirom etry suggests that this group of affected w orkers have m ild restrictive and obstructive ven tilatory insufficiency. The 4 city em p loyees studied revealed no d efin ite trend. No ev id en ce is p re s e n t to in d icate th at th ey have b een affected by asb estosis. 1. W illia m s, R. and P . H ugh-Jones. The R ad iological D iagn osis of A sb e sto sis. Thorax, 15:103, I960. 1 7 82. 0 (2)* 7 0 .7 (7), 232 t y . 2 8 7 6 .0 (1) 66. 5 (4) 275 (3) 3 5 85. 7 (3) 8 3 .0 (3) 190 (3). A 3 8 4. 0 (2)- 9 2 .5 (2): 225 (3) 5 2 75. <T( 1) ----- (0) -- (0) 1 8 6 .0 (1). 77. 0 (1) 140 (1) 7 1 6 4 .0 (1) 4 8 . 0 (1); -----(0) 8 1 7 9 .0 (1) 8 8 .0 (1) 200 (1) T otal 28 m ea n s 8 0 .7 (12) 74. 1 (19) 222 (14) M ean all w orkers # V alues in parenthesis indicate no. of record s. 134. 1 160.2 156.8 ~ 150. 3 2 1 3 .0 189.0 189.0 8 1 .0 155.0 1 0 1 .5 * ' s r'l s. ! 'M,, *1,, 2 PLAINTIFFS EXHIBIT STUDY OF THE EFFECTS OF AS INDUSTRIAL HAZARD IN INDUSTRY: I . E valuacin of C u rren t and P ast Hazards A- Review of causes o f deach of: em ployees who d ie d w hile employed em ployees who d ie d a f t e r re tire m e n t em ployees who d ie d a f t e r changed jo b s I d e a lly , would lik e to.know: age a t deach le n g th and type of occupation in th is p a r tic u la r in d u stry previous or la te r occupations and th e ir, d u ra tio n known m ed ical c o n d itio n s p r io r to d e a th ( h o s p i t a l & m edical c a u se - and c o n trib u tin g causes o f d eath (d eath c e r t i f i c a t e ) records) B. Review of reaso n s fo r: p. re, m a,tu re r e tir e m e n t() m th.e i.n d,u s try job changes ) J as a whole and by d iv isio n s w ith in th e in d u s try r e la te d to exposure C. E v a lu a tio n o f p re s e n t h e a lth s t a t u s o f c u r r e n t employees and com p a r is o n o f t h e i r h e a lth s ta tu s w ith t h a t o f s im ila r men n o t exposed to a s b e sto s . The c o n tro l group would have to be c a re fu lly chosen to allow sim ilar p ro b ab ility of illn e s s and/or degeneration fo r a l l ocher reasons except exposure to a s b e sto s . Demographic, h is to r ic a l, personal h a b its , socio-econom ic and m edical care fa c to rs would have to be considered. Measurements o f p re se n t h e a lth s ta tu s used f o r com parison would in clu d e : m edical h is to r y o f m orbidity* 3esh^*^wytiaitiaiffa$8fB8^fl9S8RrP ex am in atio n , anfl o&j'fettlve m easures of body function. I I . E valuation of E ffects of Control 1. Change in incidence 2. Reduction in progresssion of d ise ase . (a ) An o b je c tiv e d e f i n i t i o n o f ab n o rm ality would have to be d e fin e d . (b) Jhe prevalence of th is abnorm ality would be determ ined. (c) An e s tim a te would be made of th e median tim e o f exposure in th o se who show th is ab n o rm ality . (d) The p rev alen ce would be re-d eterm in ed a f t e r a tim e approxim ately ; equal to the median time for development of the abnorm ality used as the c rite rio n of change. I"* PLAINTIFF'S The in cid en ce would be c a lc u la te d . Kri E X H IB IT LITERATURE SUMMARY Although wo appreciate that the industrial ph ysician is w ell aware of the m ed ical problem s a sso cia ted with pulm onary a sb e sto sis, it would se e m proper to inform ally sum m arize som e of the m edical literatu re p a rticu la rly a s it r e la te s to the c a se in que stion. A. Pathology P ath ologic studies fa ll into two c a te g o r ie s. The f ir s t, w hich m ake up the m ajority, are those which are concerned with the autopsy reports from humans who have pulm onary a sb e sto sis and/or who have been exp osed to a sb e sto s inhalation. The second group are experim ental anim al stud ies. Both types of stu d ies have certain in ad eq u acies. The human studies suffer from the fact that they rep resen t only the end stage of the d ise a se and they do not give insight into the ea rly develop m en tal p r o c e s s e s . The an im al ^ stu d ies, on the other hand, do not n e c e ssa r ily p a r a lle l the human findings w hile they do give som e insigh t into the developm ent of the d ise a se . Sum m arizing both togeth er we can point fir s tly to the obvious discrep an cy b etw een the actu al w eight of s ilic a te s found in the lungs of asb estos w orkers at autopsy and the sev e r ity o f the d ise a se T h is sim p ly illu stra tes that not a ll individuals respond to the sam e d eg ree nor on the other hand 'a'rif s TIff S iS S S l o f two ty p es: 1} a nodular d evelop m en t in the s m a ll b r o n c h io lo e s; and 2) a fib r o s in g le s io n w hich can lead to the sca rrin g and o b litera tio n of a lv e o lo -c a p illa r y a r e a s . E ven in the B ritish populations w here the incidence of cen trilob u lar em physem a and ch ron ic b ron ch itis are high the a sb esto sis w orkers dem onstrate v ery little evidence o f em ph ysem a although occa sio n a l bullae and cen trilobu lar changes are found. In at le a s t ) one rep ort, far advanced c a se s w ill tend to show a high incid en ce of b r o n c h ie c ta sis. The other c la ss ic a l c h a r a c te r istic s of the d isea se are the m arked p leu ral changes and the developm ent of both pleu ral and lung m align an cies. There i s no sim ple way co m easure p ro g re s s io n o f d is e a s e as a r e s u l t of che momentum from i n i c i a l d is e a s e development* As ch ere is no echl-~ c a l way co scudy exposed and unexposed defrzm ra*cases co ev a lu a c e che v a r ia c i n in d is e a s a 'Tdeveloptnenc, c h is method o f e v a lu a c i n w i l l be moscly su b je c tiv e and noc as v a lu a b le as c a lc u la c i n of in cid en ce ra c e s ac scaced in te rv a ls a fte r concrol is in iciaeed . IN THE COMMUNITY: I. M ortality Comparison- of age and sex s p e c if ic d eath r a te s from a l l and s p e c if ic causes w ith chose of che United S ta te s as a whole and w ith ocher s im ila r communicies noc exposed co asb esco s. I I . M orbidity (a) A nalysis of d iag n o sis fo r which s o c ia l s e c u rity is given b e fo re age of re tire m e n t. Exam ination of a sample of re c ip ie n ts to v e rify o r add diagnoses. (b) Search fo r morbidicy data c o lle c te d by the N ational H ealth Survey. (c ) E x ecu tio n of a m o rb id ity su rv ey among a sam ple o f che p o p u la tio n to compare e ith e r w ith the r e s u lts of th e N atio n al M orbidity Survey o r a su rv ey among a s e le c te d c o n t r o l p o p u la tio n . (d) Comparison of diagnoses o f age s p e c ific h o s p ita l adm issions w ith published data o r w ith a s p e c ia lly c o lle c te d c o n tro l sample. To e v a lu a c e th e e f f e c t s o f c o n t r o l o r rem oval o f any h a z a rd -- some o r a l l --an aly ses would have to be re p e a te d a f t e r a sta t& T in te r v a l o f tim e (probably 5 - 1 0 years). > I:AlNiirr i EXHIBIT io f i e o s o & C ?) sum m ary, the prim ary pathologic le sio n is a fib ro sis at the le v e l of the sm a ll lung rad icals and a lv e o lo -c a p illa ry su rfa ces, u su ally w ith m in im al secondary ob stru ctive an d /or em physem atous ch an ges. The fibrosing p r o c e s s see m s to be d irectly related to the takeup of the a sb esto s fib er s in the le s s than 10 m icro n s in length s iz e , by the alveolo m acrophages and fib ro cy tes. There are som e thoughts that the fib r o sis can occu r interm ittently following the cucooesron of exposure due to the lam ination and breakdown o f a sb esto s fib ers which have been en closed in a p ro tein a ceo u s m a te r ia l. B. C linical and-Rudiologic P ictu re in R elation to P ath ologic and Functional Change. The clin ica l picture of these patients is u su ally that of " alveolo-cap illary block" with the additional elem en t that any resp iratory d is e a se w hich would be com m on to the com m unity, i. e ., chronic bronchitis^m ay cause a sign ifican t ov erla y . The c la ss ic a l clin ica l picture of a lv eo lo -ca p illa ry block is that o f a sm a ll lung with minimal* p h y sica l sign s, dyspnea at fir st on e x e r c ise , eventually at r e s t, accom panied by clubbing and ) c y a n o s is w ith r ig h t v e n tr ic u la r s tr a in and e v e n tu a W a ilu r e . It m ay be im p o rta n t**oapo in t out that such patients do not appear to be short o f b reath to the exam in er as e a rly in the d ise a se as do patients with obstructive airw ay d ise a se w here the w ork of breathing utilizing a ccesso ry m uscles of respiration is obvious. T here are considerable discrepan c ie s betw een the x -r a y p ictu re and the c lin ic a l sym p tom s on the offhor hand a n d /o r the resp iratory function tests on the other hana. In g en era l, one m ay say that the p resen ce of an x -ra y lesion strongly suggests a m ore sev ere d ise a se . H ow ever, when one com es to the im portant question of p ro g ressio n of the d ise a se eith er in the p resen ce of continuing exposure or after cessation of exposure the x -ra y b ecom es a le s s valuable tool. * and p h ysiological p rogression is not uncommon in the absence of x -r a y change. C linical Physiologic evidence of d isease has been described in the p re sen c e of negative x -ra y s <md w ould be a n t ic ip a t e d . A g a in , x - r a y , c l i n i c a l , a n d p h y s io lo g ic s e v e r i t y a r e r e l a t e d to the length of exposure how ever, th ere a re m any ex am p les in th e lite ra tu re of cases of-short term exposure, i, e ., 18-24 months with sev ere d ise a se . The p h ysiologic testin g resu lts are what one m ight expect from the pathologic r e su lts. T hese would be sm a ll total lung volum e, an in crea se in com pliance, a reduction in diffusing capacity, with eith er norm al or borderline a r te ria l oxygen tensions at r e st which fa ll on e x e r c ise at le a st during the acute sta g e of the d ise a se , and alveolar hyperventilation. On the other hand, obstructive airw ay d ise a se p lays a very sm a ll p a rt and in th is p a r tic u la r c a s e one should n ote th at t e s t s su c h a s the fo r c e d v ita l capacity and F E V -1 s e c . are aim ed prim arily at determ ining obstructive airw ay d ise a se . It is equally im p ortant to b ea r in m ind that'w ith the high p r e v a len ce o f ch ron ic o b str u c tiv e airw ay d ise a se which is ia the o f this country, probably secondary to cigarette, sm oking, that the identification of such d ise a se by ob jective m ethods such as the m easurem ent of airw ay r esista n c e or conductance and resid u a l volum es would be im portant in spparating its effect from that of a sb esto s. P L A IN T IF F 'S g j EXHIBIT %dA&c^< -viC/o)