Document mpvJr91oJZpQvkXEdQ7jQ0K4g

FILE NAME: Avondale (AVD) DATE: 19 DOC#: AVD DOCUMENT DESCRIPTION:WDZWEt /,ZZZZWZyZ ZWZ/ZW^ZE^ MD-006136 -~~ ~ .~itt ASBESTOS EXPOSUU AND PUIMONARY X-RAY ClfANGES TO PIPE COVERERS AND INSUIATOB.S AT PUGET SOUND NA.VAL SHIPYARD* J C. A. MANGOLD, I.. ll. BECJCErr, D .J. BISSM!R Indu1trial Hyaiene Divt1ion Puget Sound Naval Shipyard Brrton, WHhingtou August 1968 '\ i I )___., '---" * The opinions expressed in this paper are those of the authors and do not necessarily reflect those of the Department of the Navy, the Department of Defense, or any other official agency. Reference to a company or a product name does not imply approval or recommendation of the product to th exclusion of others that may be auitable. Thi paper for presentation at the annual meeting of the Pacific ~orthwest Section of the A.-nerican Indu1trial Hygiene Association at Richland, ~ashington on October ) 3 - 4, 1968. '-----" j ABSTRACT. A 2-1/2 year comparison of chest X-rays of 6571 production workers and 420 clerical workers at Puget Sound Naval Shipyard show that Pipe Coverers and Insulators handling asbestos have 21.21. diagnosed pulmonary abnormalities as a group compared to the next highest incidence of 3,57. for boilermakers. with some asbestos and silica exposure, and less than 11. for clerical workers, with no knot.m asbestos exposure. Exposure patterns suggest that the current TLV of 5 mg/M3 for asbestos may be too high. l. INTRODUCTION. Numerous authors describe many case of asbestosis and the increased risk of lung cancer for insulation workers vith regular exposure to asbestos or asbestos-containing materials (l,2,3,4,5,12,13,14). Fleischer (1) found few cases in l946'ofasbestosis among insulation Yorkers in Eastern Navy Shipyards and minimized the potential hazard because dust levels were below the threshold limit value. Asbestos exposures to insulation workers during ship overhaul at Long Beach Naval Shipyard were evaluated in 1965 by Mar~ (4) shoving asbeatosis remain.a a serious occupational disease at Naval shipyards. Nearly all of ) Marr' work was done with the Bausch and Lomb Dust Counter. Balzer (7,8) reported in 1968 that insulation workers in the San Francisco Bay area were exposed to overall environmental dust counts near the threshold limit value; however, definite radiologic lung changes were observed in the asbestos union population. Approximately 251. of the men with over 20 years work experience a.nd a 451. time weighted exposure displayed radiologic lung changes. His studies however, did not include Naval shipyards. Cooper (6) and Balzer (7.8) point out that the midget impinger sampling used in determining dust concentrations includes ~11 dust, and the asbestos dust that'is counted is mainly grains although some fibers are included. Lynch and Ayers (9) have suggested that the 5 mppcf threshold limit value is no longer a good measure of asbestos exposure, because short asbestos fibers are largely below the resolving power of light field microscopy. Cralley et al (14) has suggested that asbestos fibers act as ~arriers for carcinogenic metals or other substances. 2. STUDY BASIS. At Puget Sound Naval Shipyard, a 2-1/2 year study was begun in 1965 to compare the chest X-ray findings and the environ::ient of 104 insulation workers vith 6S71 production and 420 clerical workers. Asbestos exposures have been periodically evaluated by midgec ic?inger J sampling and counted by light field microscopy since 1956 (10,11). Toe same methods were used in this study to compare data collected over the past 12 years. 1 3. COMPARATIVE REVIEW OF CHEST X-RAYS, Most X-ray evaluations ware based on severitl revieva over the 2-.l/2 year study period. Those workers who were exposed to lung hazardous conditions received semi-annual 14 x 17 inch chest X-rays, all others received annual 70 mni chest X-rays. l'hysicians listed the X-ray findings a.s "fibrotic changes," or "pulmonary abnormalities." Table I shows tbe distribution of diagnosed pulmonary fibrosis, or other abnormality for each trade category. Because the insulators had the highest incidence (21.21.) compared to all other trades, the work history was investigated. Table II compares the age, employment, and first pulmonary abnormalities for 22 insulation workers. Table III summarizes the only case diagnosed as asbestosis reported during the study. T.ible IV shovs the distribution of pulmonary findings compared to the years exposed. No cases of lung cancer were reported in the study group. 4. Ei"VIRONMENTAL REVIEW. Airborne samples wr colle~ted and counted according to the method &~opted by the National Conference of Governmental Induatrial Hygienists in 1942 (10,11). Partiele size distributions ) were calculated for 2oi of the samples. The geometric mean diameter did not exceed 2.3 microns by the light tield method for any sample. Many asbestos fibers were probably below the limit of resolution of the microscope (1 micron) (9). Th number of fibers observed were related to the type of material. The materials described in Tabla V are used by ne&rly all insulators at Puget Sound Naval Shipyard. Th asbestos products are similar to tho$e used by union employees in the San Francisco Bay area (7,8) and Long Beach Naval Shi~yard (4). Thoroughly wetting amosite or other asbestos ~terials was found to reduce airborne particulate levels by one-half to two-thirds compared to dry handlina techniques. Wetting amosite or magnesia block before ripout of old insulation aboard ship is not practical because the adhesive and paint coating is water resistant. Installation or ripout of asbstos insulation aboatd ship produces high concentrations of airoorne asbestos dust. Adequate ventilation and wet handling techniques in the fabrication shop keep the dust levels ~ell below the n.v. Table VI shows th estimated time weighted axpoure to asbescos determined from work schedules and fie~d sampling. The exposure patterns for each insulation job on new ship construction, overhaul, and prefabrication are estimated in Tables VII, VIII, and IX. Graph A shows a typical sawing op@r~tion wh@ra A~eAssive @xposurQs oeeur !or brier ?@riods. 2 Although dust r~spirators have been required for installation or ripout of asbestos a.board ship since 1956 1 this survey found that 761. of the insulation workers did not use dust respirators. Over 50'7. did not possess respirators which are readily available at tool rooms. 5, DISCUSSION, The exposure patterns of insulators at Puget Sound Naval Shipyard are intermittent, largely chronic low level, but include brief acute high level episodes during sawing or overhaul of ships when olJ insulation is ripped out without pre-wetting the material. Individual exposure patterns vary widely within work groups because of high mobility, individual work patterns, variety of job assignments, and the use of many different materials. Tile insulators have a comparatively light exposure when compared to asbestos miners or fabric manufacturers, yet ~fter about 10 years of exposure chest X-rays begin to reveal increased diffuse markings. Change of job status, termination, or removal from the hazardous duty list may obscure the past occupational history of- insulation workers. There is a need to develop a uniform classification for reading and identifying such X-rays taken of insulation workers (14) and to rnGintain their occupational history. Iheindividual habits of workmen appear to play a large part in their exposure patterns. So~ workmeu wear their respirators, while others will not. Most iruulatioft vorkar1 were aware that exposure to asbestos, even at lov concentrations, is hazardoua. The attitude prev~ils that the hazards are unavoidable and must be accepted as part of the trade. Total dust counts are believed to be important because some of the grains are actually particles from the asbestos fibers or the parent rock in the asbestos vein. They are in fact crystallographieally indistinguishable from fibrous asbestos (9). Binders, metals from processing (14) and surface absorption may play yet another role . Until these uncertainities are resolved, the fines associated with asbestos products should not be treated as inert material. Th 2l.2t diagnosed lung abnormalities found.in insulation workers compared with 251 (7,8) found in union insulation workers in the San Francisco Bay area. The 3.51. occurrence of pulmonary abnormalities among boilermakers with marginal exposures to asbestos and silica may be partially due to asbestos. 6. CONCLUSIONS. A 2-1/2 year comparison of chest X-rays of 6571 production workers and 420 clP.rical workers at Puget Sound Naval Shipyard showed that 104 insulators handling asbestos have 21.2~ diagnosed pulmonary abnormalities compared to the next highest incidence of 3.57. for boilermakers with some asbestos and ~ilica exposure, and less than 11. for elerical workers with no known asbestos exposure. ) l Only one case of asbestosis was diagnosed since July 1965 when the study was begun. Exposure patterns and the high inciden~e of lung abnormalities that the current threshold limit value of 5 mg/M3 for asbestos too high. Lung abnormalities of insulators are first evident after about exposure and pr~gress until retirement or termination. suggest may be ,~ l0;years Insulation workers handle asbestos materials between 70 907. of the work shift. The exposure to asbestos dust is intermittent, although brief episodes at concentrations considerably above the TLV do occur during sawing or ripout. The total airborne particle count ranges about 5 mppcf for about 501. of the work day. The asbestos content of the materiala ranges from 15 to 95X. The work day has periods of inactivity, time between job changes, and time for material ac1uisitions, which reduce the actual exposure to about 6 hours. A high incidence of lung abnonialitias would not be expected accordin1 to time weighted exposures compared to the present TLV. This is contrary to the 21.2t pulmonary abnormalities amon1 insulators shown in Tabl I. Possible explanations are: a. The pulmonary abnormalities are the result of intenaitcene peak exposures throughout each work day for more than 10 years. The time weighted exposure estimates are low and do not reflect the true ex~osure. b. The threshold limit value has been set too high. c. Methods of evalua~ion do not properly access the exposure pattern. The 21.2t pulmonary abnormalities found among insulation workers at Puget Sound Naval Shipyard compare to 2S't found in union insulation workers in the San Francisco Bay area (8). If woTkina coaditiolUI remain the 1.me1 abo~t 2oi of the inaulation workers at Puget Sound Naval Shipyard can be expected to have some pu~~onary abnormalities distinguishable by chest X-rays after 15 years in the trade (Table IV). J 4 REFERENCES (l) Fleis~her, W.E.; Viles, F.J.; Glade, R.t.; and Drinker, P,: A Health Survey of Pipe Covering Operations in Constructing Naval Vessels, Journal of Industrial Hygiene & Toxicology 28:9 (January) 1946 (2) Selikoff, t.J.; Churg, J., and Hammond, E.C.: Asbestos Exposure and Neoplasia, Journal of American Medical Association 188:22 (April) 1964 (3) Keane, W.T., and Zavon, M.R.: Occupational Hazards of Pip~ Insulators, Archives of Environmental Health 13:171 (August) 1966 (4) Marr, W.T.: Asbestos Exposure During Naval Vessel Overhaul, American Industrial Hygiene Association Journal 2S:264, 1964 (S) Selikoff, I.J.; Churg, J., and Hamnond, !,C,: The Occurrence of Asbestosis Among Insulation Vorkers in the United States Nev York Academy Sci. 132:139 (December) 1965 (6) Cooper, W.C.: Asbestos as a Hazard to Health, Archives of Enviroamental Health 1S: 28~ ( September) 1967 (7) Balzer, J.L.: The Work Environment of Insulating Workers, American Industrial Hygiene Association Journal, Vol. 29, No. J (May, June) 1968 (8) Balzer, J.L.: The Industrial Hygiene for Insulation Yorkers, Journal of Occupational Medicine, Vol. 10, No. 1 (Janua.-ry) 1968 (9) Lynch, J., and Ayer, R,; Measurement of Asbestos Exposure, Journal of Occupational Medicine, Vol. 10, No. l (January) 1968 (10) U.S. Public Health Service Publication, #614, 'Ihe Industrial Envirotui:ent It' Evaluation and Control - Counting and Sizing Airborne Dust, 1966 (11) Standard Procedure for Sampling and Counting Dusts, adopted by the Sch annual meting of the National Conference of AGCIR, American Industrial Hygiene Association Journal (Nov-Dec) 1967 (12) Kleinlidd, M., et &l "Mortality Experience in a Group of Asbestos Workers, Archives of Environmental Health," lS:177-180, (August) 1967 (lJ) Tabershaw, I.R., Asbestos as an Environmental Hazard, Journal of Occupational Medicine, Vol. 10, No. 1 (January) 1968 {14) Cralley, L.J.,. et al Research on Health Effects of Asbestosis, Journal of Occupational Medicine, Vol. 10, No. l (January) 1968 5 ' ).....__.. INCIDENCE OF DIAGNOSED PULMONARY FIBROSIS TRADE TOTAL WORKING FORCE WORKERS WITH PULMONARY FIBROSIS OR OTHER ABNOR..'-'AL X-RAY FI~'DINGS NUMBER PERCENT Shipfitters 890 6 71. Sheetmetal Workers 489 6 l.21. Forge Worker 32 Welden 998 ll l.17. Inside Machinists 536 Outside Machiniats 490 Boilermakers 115 Electrician 574 ) Pipe Coverers & Insulator 104 ----- Pipefittera 765 Shipwrights & Joiners 228 l .21. -. 4 3.St - 22 2l.2t 6 8-Z. Electronics Workers 280 Painters Riggers 263 4 1.51. 664 l . lt Temporary Services 143 1 .71. Control Group (clerical workers) 420 l .Z't ) August 1968 . TABLE I ,) - ---- ) '--- ) ..__, !1PLO'iEZ: 1 2 3 4 s 6 7 8 9 10 ll 12 13 14 lS 16 17 18 19 20 21 22 AGE WHEN HIRED 22 22 18 27 26 39 31 30 25 28 41 36 - 4,5 35 49 38 54 31 57 47 22 August 1968 INTERVAL BETWEEN EMl'LOYMENT AND FIRST XRAY I~'DICAIIONS OF LUNG ABNORMALITY YEAR .!!illQ 1933 1933 1936 1939 1941 1941 1942 1944 194, 1947 1947 19.51 19.52 1952 1953 1960 - 19S& 1961 1961 1961 1963 1965 CHEST CONDITION 1st NOTED 1959 1954 1958 1963 1947 1953 1961 1951 1963 1965 1964 1963 1962 1958 1962 1960 1960 1966 1961 1962 1965 1966 INTERVAL BETWEEN EMPLOYMENT A.ND 1st X-RAY ABNORMALITIES 26 years 21 22 24 6 l2 19 7 18 18 17 12 10 6 9 - 2 s l 2 1 TABLE II .. YEARS IN PC&I TRADE AT PSNS (,WHERE KNOWN) JJ 33 30 27 25 2.5 17 22 21 20 20 15 ll 6 8 s 5 5 3 l ----- EMPLOYEE NUMBER 7: CASE HISTORY ~ 1942-52 OCCUPATIONAL HISTORY PC&I at PSNS PROBABLE ASBESTOS EXPOSURE unknown CLINICAL HISTORY X-ray: negat:i'II 1952-60 1960 PC&I maintenance work, apartment houses PC&I ac PSNS * intermittent, les than 5 mppcf lesa than 5 mppcf Xray: negativ 1961 PC&I at PSNS leH than 5 mppcf Pulmonary abnor ities 1st noted X-ray 1967 disability retirement Asbestos found lung during sur 1967 compensation awarded for disability dua to ubeatoaia ) * S mppcf i1 the current recommna.ded thrhold limit value for asbestos ) August 1968 TABLE III ( \__, YEARS AT PSNS 0-5 6-10 11-15 16-20 21-25 25+ NUMBER OF WORKERS 25 28 11 20 1 7 All[:USt l968 (0 (0 DISTRIBtrrION OF LUNG ABNORMALITIES AMONG PIPE COVERERS AND INSULATORS INCIDENCE OF DIAGNOSED PULHONARY FIBROSIS OR OTHER ABNORMAL X-RAY PllH>lNGS MEDIAN AGE 37 47 43 48 51 56 ~ . HUMBER WITH PULMONARY CHANGES 2 s 1 4 4 . 6 PERCENr OF INCIDENCE BY GROUP 8'% 18'L 9'% 20'% 57'%. 901 PERCENT OF INCIDENCE BY TOTAL PC&I YORK FORCE 2% 5~ n. 441 41 61 AGGREGATE = 21.67. TABU~ IV - INSTJI.ATION MATERJ;.AL AND US! A.t.'iOSITE Use: Piping, fittings, machinery units and large or irregular surfaces Composition: Long fiber asbestos 95?. MAGNESIA BLOCK INSULATION Use: Tanks, boilers, valves and pip 8.S"t Long fiber aabestoa AS!ESTOS CEMENT U: Finishing &nd insulating. used aver bare metal or inaulacion and aa . filler Composition: Johna-Manville #301 Asbestos (Cryaotile) Portland Cement l7'Z Clay 33'%. Mineral wool 20'%. Diatomaceou earth l.S: One-Cota Nodulated fiber and Albesto (Crysocila) less than soi Portland Cement less than 30'%. Oiatomaceou1 earth less than 201. Clay Calcium sulfate or nitrate leas than 301. less than Sl ) Or;:a.nies trace August 1968 TABLE V INSULATION MATERIAI. AND USE (Cont'd) UNI:BESTOS Use: Piping up to 30 inches in diameter, very little is used ac this time Composition: Finely ground asbestos fiber Waterproof adhesive ASBESTOS CLOTH Uaa: Final coat or lagging on piping, valvea, taiika, fittings, and machinery installations Compoaition: There are three weights ran11Ds from l.25 to 2.4 lb/~ j 80~ to 95~ Crysotil or Amoaite ubestoa fiber with cotton fiber FI:BERGtASS Use: Many types such bate,, sheets, molded piece and felt are available for different applicationa auc:h u veut ducts, piping and valve Compoeition: Fibrowa glaa, with binder Use: Refrigeration and air conditiozuq pipiq Compoaition: Vegetable product RUBBER U~: Refrigeration and air conditioning piping, replaces cork in 1110at application Compoaitiou: Foam rubber ) August 1968 TABLE V (Cont'd) AVERAGE TIMEWEIGHTED EXPOSURE TO INSUL\TION MATERIALS* OPERATION AND 1-fATnlAL ,Installation Amo1ita in,tallatiou Magnesia block insulation cutting and iMtalling Abe1t0 Cloth cutting, glueiq am fitting Asbestos Cement mixing Fibersl, Rubber, and Cork . PERCENT OF TIME EXPOS?.:D NEW SHIP CONSTRUCTION SHIP OVERHAUL lO"L 11'7. 39'4 351 151. l"L 1'1 lll R.ipOut ) Amoit Masnesia block izusulation, Amoaite, axul 'Um.beto Fiberglua, R.ubber, mill Cork Prefabrication in Shoe Magneei& block inaulation, .\moait and Abetoa Cloth _Fiberalua, Rubber, and Cork 177. 51. Percent of time Exposed 50%. 25% * Baaed 011 6 hour work day. ) August 1968 TABLE Vt (G t '"- Material~~ _Qe.eration Amosite; Installation Magnesia block insulation: cutting and installing Asbestos cloth: cutting, glueing and fittins Mixing asbestos cement Fiberglass, rubber and cork HEW SHIP CONSTRUCTION Airborne Dust Concentration in Breathing Zone (Hlllion Particles per Cubic Foot) llange Average 2.6 to 8.9 .S.6 2.4 to ll.3 6.1 3.1 to 4.6 11.5 to 82.8 --- 3.6 47.5 . --- August 1968 TABLE VII C,_J Percent of Time Exposed (Average) Based on a 6 hour daI 10% 39% 20"l 17. or less 30% - - ( \ C.__1 (0 ------ SHIP OVUHAUL Material ~~....Qe,eration INSTALUTION .Asbestoa clothi cutting, glueing and fitting Airborne Dust cou.centration in Breathing Zone (Million Prticlea per Cubic Poot) Range Average 2.8 to 5.7 4.l Magnesia block insulation: cutting and installing 3.5 to 40.5 16.7 Araosite Fibcrgla&s 1 - and cork Jt.IPOU'f rubber Amosite 2.6 to 8.9 4.5 --- -:. --- . 1.0 to 1.1 4.4 Magnesia block insulation and asbestos cloth 2.6 to 6.8 s.o Asbestos cloth and - unlhci::tos F lbcn_.}ass ruhi.,- 2.8 to 17.4 6,7 Percent of Time Exposed (Average) Based on a 6 hour daI_ 151 351 111 131. 41 17t 171 - ( ', '-----' (\___) (0 Haterial~~~<L__Qe_eratlon Magnesia block insulation Amosite Asbestos- cloth Fiberglass, rubber and cork PREFABRICATION IN SHOP Airborne Dust Concentration in Breathing Zone (Killion Particles per Cubic Foot) Range Average 1.1 to l.l 1.2 (cutting) .32 (glueing) 2.4 (cutting) .39 to .41 .07 to .1 .l to .15 .4 (sewing) .09 (glueing) .ll (pinning and marking) Percent of Time Exposed (Average) Baaed on a 6 hour day 671 --- --- llt :: August 1968 TABLE IX - ( '''------ ( , \__,- u l- o .~) LL U 1-2 m:1 ::> 0 OU a: W bJ 0.. _. _.U} l.) i..=. u : W I': <i - I:!. lo-:: .,.J <{ ~ n. 1- 0 -e~.> l- ~ .J _J --C GRAPH A RELIEF SAWING A-ND HANDLING MAGNESIA BLOCl< INSULATION CONTAINING 8r LI) 15% ASBESTOS FIBER (\) 85% MAGNESIUM CARBO NAT~ 0 N \ 10 - I I I \ \ I I \ I 1. B ND SAW RELIEF \ 0 - 1 I D HANDLING \ I I : c~ REMO VAL OF. BLOC!( I C') Ffl OU CO)( ES AND ,~~I - STJ\Cl(lrJG 2.9 30.I ~ 5 /o~IAI ,fI;) 0L740----I ----2l,--o--3 '--.4-4~~4 ~I --5=--~6-----7 ----8---- nn SELECTED ~ E S R!UTXD TO ASBESTOS SXFOSUR!S OF COVER.DS AND INSULATORS l. Fleischer, et al, A Halth Sw:vey of Pipe Covering Operations in conatructing Naval Veesela, J. Indult Hyg & Tox 28. 9 January 1946 ea An ezcellent referenc: that shOVII hov littl the xposw:e patterns and tr.Se thod have changed. Th authors cone luded that the number of dialno1acl ubest01l refleeted the hazards, which hu inc bea found not to be trua. Moet PC&I personnel do not file daJ.ma. 2. Marr. tl.T., A1be1to1 !xpoeure During Nnal VeHel Overhaul, AIRA J 25:264 May 1964 Marr' wrk bettar reflect the apoaun pattenw and th potential hazm:d from a1beto apc,a:rea. 3. Selikoff, l.J., et al, Akta bpoure &Del Neopl&aia. JAMA April. 6 1964 wa SelU:off' article augpaull that a high rat of cancer ta abe tou. related ) 4. Baber, J. IAray, Indus:r1:tj JIYsina for luulation Vorkar, J Occup Med, Vol 10 11 1 Januay 196 --.....,., 'Ih.1 tJuiveraity of California naarchar fouul iza the union insulators aJ,od th saa rate of pulmoaary abaormaliti u found at PSNS. 5. Se likoff, I .:r., et al, Aabeato !zpoaure Smok:ln5 apl Neopluia, JAMA April 18 Vol 204 12. 1961 Salikof! UnW ~ldna to high rat11 of c:ancar amns .ubeatos workers. 6. c.A. Mangold. ll.l.. -.ct:~, D.J. JeHr, ubaat,o !!e=- am Pulmggrz x-ray ctiau to Pipe CDftrff pd IaaulataTt at Pupt Souacl Naval Shipyard. tnduat:r1&1 BJgina- Dinaiaa, PSRS, Auauat 1918 .ubeto vorbtt at PS1'S haw m ..,.rap of 211 pulmnary abnarmaU. ties. c:capancl to all othaz work groui-. the pereentqe of pulmonary aba:ormaUti ~ b:, year in the ti-ad are: (1) 15 to 20 yrs--201; (2) 20 to 25 yra--57'%; 2.5 yrs + -90'%. - r I ' t~ r-s,, ,-'<:> .~ .__::, r I { 1 a -- t: ~~ <..c ..-... d. .. -.a.: ,...-----.~ .:~ ' I N Fl:BJ!t'MY OT nas entitled, "Asbestos n:.u Cooper. m a paper as a Huard ic Health,"1 co!'l"'.Jnent~ as follov;s; "We often try to emphasue that par. of t.he challenge o! our field is that it JS at the forefront of meweine and technology wher'll env1ronment.al haurds can f.:rst ~ de-tected m V;PW r.tr lh.- -,.-...,~... , ;.._,,o ~a.,a~_-.;- nf MVf'Wl..._l_1't,-- .. n~ f}u~ '-uoJM opportur..:ues to study populations ;t r.:sk.. But Asbestos as an Envicoomental Hazard when the relatioruihlps are aetua.U~ SUS!)l!eted and gradually e-st:1.bllshed. very i-eal and p::.ictical con sequences become- app;.ren:. So the Sp@:ula~ons, call them fancies if you will, that are pa..--t of the normal processes of developing new knowledge m other fields become menacmg :am: are misused and misunderstood." You have heard today that in industries 1.JS'.ln!l :,c'bocto :u: " b:,sie rn:,tori..al. tha~ i.i: mi,,ing, mill- ing, fabrication and i.nst.al.iauon. that a ttlatton- sh.p ha~ ~en estabhsne-i he\we~n asbestos JRVING R TABER.S!{AW. '.\-1.D. exposure :ind fibrosis of the lung. lung aneer. and possibly with an increase m the incidence of me,othelioma and ga.stromte5tmal m.al:gnanc1es, The incidence and Sl!'ver:t:;: of the p..t!.I!'lona.ry fibrosis 1as~stosi.s) are apparently dependent on dose. This dose-response relauonshlp ir. asbestoi1 worker~ will probably be proven in b:ne to be ~- . tgrausetroailsnotefsotrintahletrnaecotplCasoinac0ernt.hheolwunegv.epr lehau.~rabaenedn expressed that asbestos in ambient all' may con .r.-, . - .._ ...... ,. \ -~.r-.r,~ st~tute a real threat to t.li.e imtu:e pubh1: and not Just to those occupat10Mlly exposed, Th!S gr-ave impi1cstJon is sununarLZed in an article by Thomson,' who raises the- Q\.lestioo of "whether a small amount of asbestos 1n :he lung bases or in the adjacent pleura or pe-moneum is ,m ,.ff,.c-t1\.'e rarrmogPn or ro<arrmogPr. m hu mans. if ,tis presel\t thi!>M for 30 yea,:s or mol'e.'' Thts concem u; reiterated by Sehkoff and h,s co- workers in :a leng->..hy editorial with th<? ~tat!! ment: "T'.1e neoplasms now encountered associated bot. w1t:1 md1.1Strv and environment are consequent upon ihha,ation of asbestos associated with the h:rnited asbest<:>s production of some 30 yea.--s ago. The neoolasrns assoctated with turrent u+.ilization and exposure to asbe~os wi!i not be ev1 C.S.R,, DIC. danced until 1990." If thlS is true. 1t changes the order of magnitude of the hazard and places as"l,es:os in the forefront of public health problems. !t l.S to this allegation that I wish to address myself. A good deal of the ~;(':~~C)~~t~\?l \}~ ~~JAi IO S:1 l Or. Tub,:r.J..,.w " P,afuwr of Occ-.1.p<tt10Mt M~ict'W!, Scl\ool of P11blic H,c!th, Un,tr,.,...,_t11 of C:itifom"', Berk.,ley. P-u,.,.c,,d at the E!euentn A.,,ntl.4! Mt'tfag of the We.rt- ...,. J'Mlwi""4! J-1e4ltl> Co<1f<trNice, Son F..._~e.,, St;>= b...- 2j 11M JO, 1,o1. 32 PLAIN'11ff EXHIBIJ i.nform;at1on on which fais potential threat is pos tulated is m !he realm of "speculation" and 1t is not always possible to separate the "fact' from the ~9,e 1lohe1nc No.~ SOA5504  I I I Tne data which lead to tills speeulatlon is most- ly epidemiologic in ~ac~r. T'oere i WltKiYivocal evidence that fibrosis of the lung {asbestosis) oecurs in asbestos workers. Pleuritls JS a frequent S&Q.1.uila of asbestos exposure and a i:a.re malig- nancy of the pleun, mesotheliom:a, shoWll 11 :remarkable increase in asbest05 workers and in individuals living near asbestos-produclll.i! mines and ,.;1,...,,:;r-~4!$. ~~;:i~asm.s of tbfl' ;u.ng oc~u.r mere frequently m uxlividuaJs who have as~stosis or who are occupatlon:i.!.l}' t!Xposed to asbestos. These findings, per se, would not lead tc the sweepmg speculations made by Thonuon. Seli.~off and others were 1t not for the add1t1onal finding that a large :percl!n';.age of tndivicluals over the en- tire world show ''asbestos bodies" lll their lu.!1gs at autopsy even though most h;:ive h1td no known occupational exposure to asbestos /Table l\. Smee '"asbestos bodles'' att specmc for past exposu.re to asbestos or s1..-nilar fibers. the speculation that all of us are ~!'lde~ :rome increased threat of hmg car.cer due to the presence of ambient .u.bertos is v:ilid. Assessmer.t of the magnr~ude of thJ.S threat JS th,- ~cial question The dynamics of the situation wul not pernnt us to w.a1t unttl 1990 for a defin1- t1ve 1mswer Fon:es such as the lllcreased u~e of a!lbestos products and ::he general soih..,g of ambient air m our 1ndustrutl technological society demand that we make some Judgment now If we can11ot make tlus determ1."1at1on. we must du-e-:1 out research mto those channels which will be most likely to givP u_~ early and definitive proof Epidem1olo1ncal studies are of prune unportanee and tn fact pre-Jent the most convincing evidence that ashf!'stos may be dangerous to the working population, but the likelihood o! pTovmg that ther11 i.s an mc:re.ued r.rsk to the public from asbestos 1n ambient au-. by wrug ep1demiolog1c; methods. 1s very small Even ii all the factors which coulc influence 1t.s evaluation are knov.:n and a prospec- ~1ve study devised to demonstrate an effect by 1990, any ronclUJ1ions from such a study wouid be subject to severe doubt because of the ma:ny T,A.ILE ! Jll11r,a,llt9 o4 A1,i.t-+o1 Bodiac ~n Lun9 Smrs - ... O""!iO"" "01""'$0 11 Cow,..~ ta Webrttr Meivl'ffl&n A"l,Jve,I .~ ~. C~o.e, & ... ~be't/"le..., J !4'63J I 1VtJ51 t!QO'S\ \l~lf.j\ 1,91)1,1 11r;;t,o1 119b6 C40fl ;0"""t' v,,,m P, .51n,,.cl ..\ohorncnbvrt; F,.,la.rd 0 '-'O"''@t1' S!!!t- ~,b .. <: ~ce r r , Zo "'ct 41,0~~ J?.2~. .5,,7goO~~o:, ,so~~ I'. t!..'01'St<;;,J"I' VP'i111tli:+d tu+oo1y MU. "1.. ,c:lt >cc--101"\$ J\QdOo<:: rot-" C.:iooe-" w c:ar~ ,.,:)uo~ J.-il!'e,'...._~a('" 4'"'C )"ec..,!&,-t,011, Arc+i fJ111...-1,o,-. !$~p1("rr:,e-,) 1Qb' ~i e ..,_.,:~r,: +c, ~H' 1S 2j. vuiables which eould. not be controlled satisfactorily. For 1,.istance, it would be almost unpo$Sible to sele(t a pr-ope, cohort which could be followed over the ma.."lY year.;: the sel~cnon of rr.atc.11ed controls wocld be almost insurmountable; the tn ere:u:mg use of asbestoi: and th~ diffttenees in composition and possible tx!)Osure in various lo- ,._:)1;., ~~~ .:-:..1 ~.c c,,n!-'~'" ,.u-:--_: :...~t:~cwced. Oy co.carc.i.-iogen.s m our envi.onrnent :unhe:r becloud the i.ssues and make lt very 1.Ullikely tilat an eqUl'>ocal lrn.5V,er could ever be forthcom:.r.g ir~m this t}'J)f' o: evidence alone. T'.ne experunental approach car. pro\'IOe only tentative a:--..swer-s since it has been deni.o~strated t.11at. while asbestos will produce u:ritation. pfaques and rnalign;incies in serous cav1t1es, :t 1S relat1vely :n.ert u a."l over-a:l UT1tant to biolog1c mate:nals Furthermore. the translation of effeet from any spe1::,e:. of animals w m.m J.S di.'nrn;.t .it bes~ and IS made even more q'JeStionable by marked vananoru.: m resi,.iratot-y tract re-spor.se by different anl1Tlal species. The ammal selected must most nearly resemble the human !u.."lg lll order :or the experiments to be :neenmdul. D1f ficulti- i.s evidencec. for mst.ance m :he fact 1:hat some- anu:nals. e g. the eat and the gumea pig. will pro,;luce fibrosis and rela.tl',dy few .isbestos bod,es. and others such as the mouse will prodt.:.::e relanvely few asbestos bo<hes but no fibrosis This is probably related to the vanat1ons m the evolution of alveolar macrophages whicr. Collet et al.~ have demonstrated to ciiffer among h:.imans, cats. rabbits, and guinea pigs Exposure factors are not completely understood. Asbestos Is said to be indestructible. but the term is a relatwe one.: high heat. chemic:il~ a."\d. body fluids produce changes in its physical and chemical proper:ies in ume There 1s undoubtecily a difference m effec! from a heavy. brief ,:,:r con:mt<ous eicposure as occurs :n J!'lciustry to a sustilmeci minor exposure which ma) occur from ambient :ur polh:tlon. ~hkoF.'- has 1~1>:rated many times tha! there 1s an i.ncreasmg use of asbestos (Table !I) and sur.ru.ses that we are pr..-sently seeing :ur.g malignancies ''consequer.t cJon mhala'tlon of asbestos 1133oc:ated w1th ~he h:mted asoE-stos of so"!le 30 vears ago .. The L"Ylphcat:on IS clear that u this r;lat1onsh1p (tons of asbestos produced to incidence of !ung malignancy) s.s true. the :multiiold increase m its use has started an up. ward trend which will be refected for the next 30 years and more This extrapola.tior. is ur.wa~ranted. Increased product.Ion cannot be equate-d with u:c:reased hazard. especially m a subs~ance like 981105 MA.RRosJ 33 2652  Asbestos Jt,:uard-Envt,.onm.rnt TA&L!; II World ~~~e+;on ol ;,_,,,HtQ, VEAR 1880 ,ooi: 1no 1~30 fQ50 1%~ 10" ~ -------~ - - - - - - ~- ...~ .... .,._d<!CPIC' te""' "I .. ..,ora S.0..1"ts '10 rCNS 500 l,\Y.lC ;?00.000 so.ooc I JOOOOC 2 30000C ; ::; ::,c~ 35<0000 l MQ()(X) a5bestos v:hich is used for the most part in produru wlueh are unlikely to become attborne. The largest amou."lt-<Jr:e can o:tly guess at the percentagt>--goes into asbestos procluct.s wh.kh, once applied do not disintegrate. s1.1ch as build- ing materiais and floor tile. A f.ur est..i..-nate mlght be tha~ some 10 to 15% 0 the asbestos in the ap- proximately 3.000 end-products eonta1m.ng this mrneral. e.g. braite lim."lg and asbestos textiles, :nay by deter!oranon. weatherrr g. he.-itmg, etc., become airborne. However. there are no studies of asbestos concentratior-.s in ambier.t au-. Ind1- catiom that asbes,cs may be carrnid conSlderable distances L'1 the ::iirsu-eam' ate based upon: (1) Analysis of deposits on the surface of the earth, snow. etc.. (2) e,:iclence that s1gn:dicant n=bers o: ~ople w:t:1 mesothehcrna worked or h\e<i near asbestos m.nes or plants: and (3) evidence that a 5ignmca11t population has asbestos bodies m their l11ngs at autopsy. But as yet the t,i:,e. :amou11t .and particle size of ambient au-borne as~stos has not lent itself :c ,ysternatlc cle~ect1on and :r.lenufica tion. It sho'.lld also ~ borne in m1.nd that asbestos deposits have mmeral outcrops and her.ce ~ere ,s a strong poss1b1ht, that asbestos in ambient air may be a r:atural phenomenon and not onlv a result of mcreaseci ~-:du.stria! activity. Chn1eal ~xper1ence mdica~es that the appear- ~nre of a;bestos,s (pulmonary :'ib:?'JSls) 15 dose- dependent. Cluldren have died of asbestosis and cor pulmonale after a few years of an overwhelm :ng expo.sure "within large shipping bags. tram pling down fii:nfy amosm asbestos which all day :cmg came ea.sc,adUlg d<)W!'. Qver their heads. "8 Slms-Cremer" gives li..'l average in one factory l!l South Afm:a of 6 years a: work ~fore asbestosis w-as mamfest. Jaeob and A.nspach,10 U'i Dresden, determined an over-all average of 30 yeill'5 before the as'oest.osis became llisabllng. X-i:ay changes are induced in most cases after 20 years' employment as an U"..Sul:ator (Selikofi, ?- 147). One of our cases showed evidence of the fibrotic process on lung biopsy some 22 yMrs after a heavy expo.nirP of less than 2 years' durauon. 34 TMl.!111 Worl:n Cl?Qttt !o Ailmli,. i~ ~ IJr,t+lld Si.+.! (1u3 c ,.. of "'~vf,ct,.........t>o+. ef c:;.,..,,,,.,.,, l ~AW 11.oowc~ UA'li,;J...C-:V~l"l& ",/0, WOR~E'<S A1i,e,01 ?redv-:ts ll~oll 951~ A>bo,.,.os P-.ot,o, ~~d,,..("t,1 {f~.63: lt.fi-4 .A.s01troa M,,.e$ &- -..ii'is -4~1 <;,11"1...,.,.... -~C .:., ... UA'J1JC.(:1.H?t~ T,~~:;~:;-; "'t .... ,,&. .. ,""' W-;:,,wkll!!J-"'$ :l~b .. , ,sooo 'While long latency ~ usua: ,'ld progrl!SS!on of !.h<t fibrotic: process may continue long afte:- the exposure has ceased. thl!?'e ls little information forthcoming regarding qua.-iutative data on the O.OS@e wb.ich each indivtdual was eicposecl to Lung ciea:ra:1ce studle3 indicate 1. marked difieien~e m the effE>Ct.s of short, heavy dust expost.tres as co:n pued to minor, low exposures. Heavy dJ.St inhalation mcites ru, acute fi.munatorv reaction and stasis tr. the respiratorr bronchiole and ad;ommg alveolar ducts and may provide a nidus for a con ;muing effect. That asbestos>S, i.e. the pneumoconio.sis. doe!l not presen~ a maior problem for- the future is most ly <iue to the f;.ct t.i.at the occu:pat1onal population a~ r1Sk, wh.irh is difficult to deternune exactly, ,s still quite small and can MV!!t reach large numoers (Table lll) Whtle me:n~rs of tht- coI'.strucbon industry, for example plasterers and s<>me automobil~ work et-s. e.g. brake repa1rmen, may have greater ex. posures than insulators working directly with asbestos products. it is s.rle to say tMt the kinds of exposure expedeneed in indU$try will never affect.any SJ.Zable group m the general or working population. The threat f:om asbestos, ht>wever, L.es in tts poss1ble assoc1;ition with lung cancer: and the ex pect.atlon tbat ".here will be no L"1crease in the morta11ty from this disease among e,i;posec workers is not so ~"l.gume Cancer of tht> 1ung occurs more frequently in those with occupationill ex J)OSUI'e, whether or not they develop fibroSIS, and ,his evidence is am;)ly subst.mtiated (Tab:e IV) Two aspects a:re not known. the pathogenic factors and the dose oi asbestos whlch produce this m- crea.sd susceptibili-:y. We dct.not know whether asbestos has preperties of primacy carci.nogenicity or whether its effect is entirely synergist:c. That other factors mu5t Potentiate the asbestos """ posu..e ha:; been postulated by Sellkoff and Hllr:l mond11 who show that a.tbestos insulators who smoke have about 90 times the incidence of lung 981105 1J RJIJ.r.rry 1958 Volume 10 No. l nAR 08 2653  TMLE IV En-1d.,,,wo1G9ie S+ud)11 ~ Ai.b.k+o-w bpotrJr nd Ft.AC~ AVTHO~ YEI\RS NO W'T..._ FOLlOWeO Ll:NG CANCE~ uo,toc' Doi, 31 l;/l~ K1t.t1eo""" aea""'!. Ou&O-~ .B"11J!'I & ! li'/6:7 ...,.1,1 ... 01;~,,vv4,ua Wi,""<.H~ & lloln9 c.. nc+ ... COM. PA~'SON Cb1001ctod .:..o.S e,oa-z11d - ~C h.le..,, Ye-~ .!, 1' .J!' ..1ev ~.,.;o,n,~ >e,o" ~ S,A = ~ ._J,J ... $ ....:. ,. .. a Ov11.>+ l w. J,c~b & i\f'!H:ia::., ; .. t,-r 1r.* ote:"li.~ 7,J 2"/286 "S.'2~S o~,.... , IC,/-'' oe-a~~ ~,.rr EC t,fi~"t\ -c.~ e1:,\~~ee --2.8 ie-x0.e::oc::' :, ~ tt'C~~,.~(- - 1I o e-rb-te-e "Aoi,oecd "Qn" v,/ C1ert Cooee-..-..,C'es:-i 0.5 ~ M0ta-rc te ~.e,.aot-i=-ac- e!t"r! S01;~ule',-... A~r:.". :"lvrcr. t..;,u!+. !5:28S 'Ser-otw,mber} 1Q6f~ mahgnan<::y of smoken who are not e:x:J)Osi'd 10 asbestos, Th" mPr.al eomple,r5 :n the a$h<-sto~ fibers (n:cke:. cl-.rorniu.'!l. etc.). benzp~'l"ene and others carl'inog.,nic ;,gents: absotb(d on the "SIX'~tos, allergic response wluch produces :iltered un:muni~-. and the inCl'eased O\.U'den from urban populattons or smoking a:rn now postulated to be the major co-factors which make as~stos carcmogcn1e.1~ A dose too srnal.i to produce fibrom. 1.e. asbestosis, ma~. nevertheless lead to 11.:.ng cancer. A dose large enougb to p:roduce asbestosis may cause mahgmmcy if the worker does not die first frorr. htS pneumoconi<lsi.s. Rowever. many men, after a lifetrme of work witll a.s~rtos productl\~cIB.cally Ul5\Uators-show no evidence of an}' unto ward pu:r.-ionary pathology. Agam. Jn all of these. the amount of asbestos inhaled is unknown. When ~ do5e is known to be related to thf' incidence ar,d severity 1rl a disease (and it grossly ap'Pllars to be the case :.r. asbestoSlS), it is safor tQ p,;1stulate that a non-threshold reiat1ons.liip exist.~. F~om a practical ~ta."ldpoint, however. asbestos would bo ar. unusu~l disease agent if it did not have such a threshold. uProof," however, will always be a speculation, as it is for e~a.m:ple m det~munmg the care1nogen1c level of radiation There 1S no way of estimating this threshold level, which at pr'.!sent needs more mdustrui.l hygienE! studies. Our findmgs suppart those of otber mvest1gators who state that pleuritis occurs in abou~ 25% 0 msulation asbestos workers. The incidence of mesothelioma m this groui:, is extremely large, con.~1dering 1he rarity of th-. tumor Seliko.fr re- porting on a S#mes of 124 deaths from neopfasi:i i.n 1nSulators fout1d 10 with mesothehoma. nus mahgnancy has also ~curred in increased incidence in some populations which did not work directly w1t.b. asbestos. lo a very !arge propo!'teon m South Africa and ill a conslcie:-a!,lc number o! t."'le the ~'lCtlm.S of this malignancy lll the united States. environ.i:ne:i.tal exposure 13 :p:;,:stulated as the cause since they b\fed close to asbe!to$ !)lMts i.:sing: espe,;:1ally amc5ite or crocidoLte.'' The evi- ==~ dence is strong th.at the source o! th'l ag,mt w.is 1.rriIIW': 1P,..-;...~~~ -:.-:e a.;~s~..,3 facto.r,}.es or :nines, even :hough man, of 'these mdmciual.s r:hd ~mt ~how an undt>rlying asbestollc fibros,s. How- ever, the a."!lbien: concentration o:- indeed~ spe cm<:: t,,re 1i! nzbestos to which the person ,.,-as exposed and w!uch could be responsible for the disease has never been determined. et:her m the neighborhood or m the workmg enviromnent AIi mcreased i.ncidence o! gastrointestmal :na iignancy is still oeing :nvert1gated. 'liut fr,e stati.-s- tical inference i.,; strol'lg that thi>rP 1~ an mC"reai;ed suscept1b:.J:ty l1l tho~e expoud to asbestos ThtS wtll ;>robably be cla.r1fiPd l''l ~1!ne F.mph,-s!!m;. o, chronic bronchitis. if it does occur as a resul: o! 1nh:il:itron of asbestos di.:st. wouid always be ob- scured by the underlymg pneumocomosu; and the diagnosis of these condmoni would alw.iys be considered a secondary ra:her ~han a primary d~ase. A link and perhaps the by to the p:-oblems he in i.mder,standing th~ role of the "asbestos body'' in the pathogenesis of the different twue ?'e- spo=~. Our experience support:; the statement of Gough:,. "Asbutos Ul au.gnosed hu;tologically by the association of asbestos bodi.es and asbestos Jll:H!n, ,,.-:th fibrn!>iS" However, what the ".;sbe5W5 oQdy" mear.s i."l indi-ndual.s who ap~ent!y have never been exposed to asbes~os .iS not clear. If this can be explal!led. iruerences then could be made with son:-,e certamt~ regarding the potential en- vl!'onrnental haz.ard, :be presence of "asbestos bodies" b tbe lung !S a b1olog:cal indicator of e:rpos-Jre to asbestos V.nethi'!" or nt other mineral fibers ca.n produce an "asbutos body" is not pertment man etNiron- mental sense The lughest eor>centration of min- eral fiber in amb1ent air i.s overwb.elnungly asbestos and hence one can assume that "asbestos bodies are almost enurely dEmved from asbestos fi.bers.'' "Asbestos bodies probablv can be found m every Jung at autopsy if sM.rcil~ for bng and hard enough and an occasion.al one is adventitious and simply mdtates that mineral fibers make up a part of the dust in our environment. 'r:he fibrosis of asbestoslS is nonspe<:1..l'ic and has no s~llll structural charactMistlc.s except for the presence of "asbestos bodies.'' Hence, inter~titW 981105 MARRosJ 2654  Asbestos H=rci-Environment fi:h:rosis. without the p::"eS!!nce of "a:;bestos bodies.. cannot be ea.Ued ubestom. Convers@l~, however. "as~tos bodies" in spu.twn o:- lung U.SS\le with out nbro$is is not asbestO&is but simply an evi" dence of exposure. Phagocytosis by macrophages is e major clea.n:s:ng mechamsm of the lung; they ,...,v,v,1; .,1-,~ ~ff~!",!1~~ !!!!!?~:-.:tl 5bc!" =:--cd.:..:.c:...."'l~ -:.he t~,cal ''asbestos body." No relation.ship has b-ter. established betw~n the numbe:. tyt:ie, ol' size of "asbestos bodies' and the tL.'"!le o: exposure, fiber si.ze. concentration, or form of aSOO$tos Individual:; who show "asbestos bodies., on luni; smears a: autopsy do not 1.1eem to have a.n inmcreased. mc1dence of any specific pulmonary disease. "Asbestos bodies" :nay be found in lung s:mea?s and not :n the cor:relatmg wsue. Cauna e~ ar.u fou.'ld that only 4% of Jun.is showed as~ bestos bodies'' on histolog:cal section, whereas smears c! the same lungs showed "as~stos bod1E>s" l"l 41';c Our findings are suni.lar-iung sn,e,ars i.r. consecutive autopsies without known exposure to asbestos revealed an mcidence oi "as- b..stos bodies" m 45% while search of the matched lung tissue yielded only 3%. This may be a fun: tion of the amount of material a"a:lable for stuc;1y since the !ung s,riea,r represents a much greatfa!r anatomic area than the lung tissue studied m histological s~t1on. Meu:rma."l foimd a c:onsiderablv h:gr-.er correlation of lung smears to lung sec;10!1$ but he used special techniques to demqn strate "asbestos bodies." Our own mterpretatmn l.'> .ha-:. wr.ile the di..'fer ences .L."l amount of material wh1ch is available for stud} may account for some of the d.!spar1tY, ther-e 1s Pv1dPnCP that mine:al fibers are cleansed. th.rough th~ macrophage systerr. and hence found m the alveoli and bronch1al lurn1.'1a but do not P'"'.tPl'" into the inter~litial tis~ue. On;y o\erwhelrnmg exposure or perhaps some other factors which permit fibers to penetrate with for:nauon of int<!rst1tial "asbcstoo bodies" lei.d to lung ma- lignancy, pleuritis and meso6elioma, "Asbfflos bod1e:s" are not ~ frequently i.~ routme his- tologic study of lung pathology. This lS not an oversight by the pathologist S"".nce section~ of lung especially stamed and stud1ed for "asbestos bodies" do not reveal an increa~ed incidence (only about 3%). Oui- present view is that asbestos fiber,;, are phagocy+.ized in the aL--ways and excreted m die sputum. In some ms<..anees the fibers penetrate fae bronchial tree, giving niie to fibrosis. or into the pleura producing pleu.ritis. Co-factors. which are not completely Ul'lderstood at pres4!nt. operating with the .11.Sbestos cause a.n iJltteasfl lJl lung cancer siJSceJ)tibility and il:l the api>e3l'a1.1Ce 0 mesotbe- !Joma. A$ the role of-Ole "asbestos body" become!! clearer and more data becomes available on the dlstr1but1on, type, fiber size. and eoncentratton of aJrb<Jrne asbestos and the role of co-facton. the hf:'.:1 ...~ U.,lllo ~ :,~ ~ :?~!~ ~~ assess ~4lc po-:.ep~ en Vl!"on.-::en-:al. hazard from th.is ub1quttous mineral In SUJ!'.1mary, l! one accepts the a.ss1.1rnpt1ons (:) that asbestos minerals mcrease the risk o: lung cancer in oc:cupatlooal groups, (2) that t.ey lead to a..'1 unusual risk of mesothel.loma of the pleura and ~ritoneum m occupattonal groul)s and those !:Ying nea:- asbestos plants. (3) that such malignancies usu.ally result froi:n expo$\U'l!S 30 to 50 years earlier. (4) that the "asbestos bodies" found m trom 2~ to 50% of lU."'lg irru!&n from routme autopsies ar!' probably due to asbestos ::n mos~ cases, (5) that these ".abestos bodies" mllY result from recent exposures as well as those lnll..'"ly years earlier. (6) that world produc:ion and use of asbestos has increas4!d n-om 500.000 tons to 3.500,000 tons m 30 vears. 1t is .importa."l.t. to consider whether or not ~besto5 is a ma;or threat to public health. One is not yet iustifitd in such a con clusion. m view of 1.e fact that much of the world tonnage goes mto uses that do not lead to air con,ammation; asbestos 1.$ not actually mde sthlct1ble, that the effects are dose-dependent, and that low doses probabl) lead to lower rates and longer latency. Nevertheless, there is need for epidemiolog1c studies directed to groups v.-'ith intermeciate ex posu.res and for evaluation of the beneficial effects of cessation of srnokmg. Another need is for exper=ental and mdustr1al hyg~ne studies to deterntlne the :1-ature and degree of e,cposure. Blolo1:11c studies centered on the meaning of the "asbe~tos nodv" are crucial :o unde:-standtng the c:.uucopailiologic: response. Strict control of In ::lustr:al and neighborhood en~lt'onments is es.sen. 0 ual, but 1~ 1.S premat\ll'e to extrapolate from the effects ot heavy exposures to minor and low level exposures. l!OG C,i::lv p,,ck Be,,kelly, Cal.If. 94708 References: COOPER, W. Cl.Mlt: Asbestos as a. Ea.zard to H:!lallbFact and Specwanon, Arch. EnL'iro,, Helm 15:Z!IS (September) 1967. 2 TlloMSO,:, J o. Asbeitos and the Urban Dwe:Ier, AM N.Y. Acad 50> 132.196 (I>eeem~r) 1965 36 J4nuary 1968 V oluMe 10 No. 1 981105 MARRoeJ 2655 l 3, Sw-xorr. l. ~ ;md H.l.11.1,\0)t'Q, t. C.: A$M$!0!l.s ar.d l'ie<lplas1a, Am J l1hd 4':437-496 (Aprll) l96i'. 4 c.,Rl>Nti, uRoi- t;. Ch1')'$0Uif: llsbestoj ..s an lnd cator of 5<.1\:/Ue Diffu-cn~s 1n Aimnal 'l:IS.'11cs, Am. Rev T1tb..,., 45:762-766 (Jw,e) !~2. no. !! SLt'lS-Clll:1'!!:P. C K Ash.o~ ,.,, So,,:h Afoco~ cmatn Gl!'Ogt.aphm,l E'onVlt'QNI\Cn\.i!l CO!\Sld"a- tlOl1S, An11 N.Y. A.cllc! Sci 132:2!5, (De~tn"I') l96S 10 JJ\tot, G. ant .._.,~.11C11, M Pulmonary N~plw1 Among DroR.lon Asffltos Worken. A"" ri Y Ae<1c!. S. Cow:r, A.. MAR't't?<, J. C.. Noll),IASl>Rt:<t':'. C a.-.d ?otieJ.~. A Rt"h~n:h~s "" l1:vohmo11 dvs Macro ;:hages Alvtoia,res-ll\hal,d PartJcies and V!"'" \ "' ~~ !.::::c-;: ~-1 : ;; i:,a,viet Pf!rg.:11,'\n91 l"'!'l!SS. ?:.d!~ Sn ll2. l36 ID~mber1 196.5 ll Sll.lROn l :. anc HMMO:<O, t C Nc-..spaper Clip- ~J.nf, !;l63 A1~. ~ci,~-! ~2 C.1t.tttrv, !-. : : Y..::tN"-''::: C :i,rd :..v,(!N. .: P.-. Ex C:u~h &. Lor-1; ls:and C1t> 10;7 c. S<W<OTf, l. J . ,he Occl.lrrtl\l:e of Pl<!ural Ca.J~.neat>!I Am~.,~ Asbes10~ lr.rul,tJon Worlc-.rs, A"" ,YY Ac,d So: 132.~51 ..307 (Dece-morn) 196:5 Y.EV~r,us. LA11R!' A:swsto~ Bodies atld Pt~m1-! Plaqu~s .n , F1:1J11.sh Sen~s of At.1.toosy Cases, .Acta Peth t~ Mir;,ob1<>L Seen,!. /Suppl 181) F,nla.nd, 196G :posJr1! tt, ~'leta~s. lT th;- 1\!arJfactu..e o: AsO<t.s:tcs Tex ti1e Procuct.s, Afl< frwi. Hyo Al!'< .' ZS ~52-461 ($~pt OcL: 19&;, !3 Lrrtt!'. JA!<: Mw,STl'IM~s "' Abu,~s Workeu, Me~- Ei.imm Hhh l3til9-ll21 (:i1wember) 1966. l I. Go1,w., J . Difier~ntial Di.agnosss "' the Pathology of AsOfostosis, A11-n. ttr"Y .A.cad Sc: l:?2.:?68 (D.e~rn':>e?) i95 lo CAVNA, I)!I:>l!A, TQ'l'r&N, R. s. and vftOSS, p: AsbesloS .;, S. ScHEnru;, G, W. H.: !liscuss,011, A"" N,Y, Ac4d Sc, Boe,es 2n !il,U't!3'\ Lungs ~t AutGps;, JAMA 192: 371-3,l 132 Z~6 :De=oer) 1365. (:>la)' 3) '.1165, 'fhe Crban En,;i,onrn<:1:lt :S111ural l'e<<.>Urc,_u; have always be..n define<i as tho~e p.ns oi tl-ie natural env:rcmment that h:ive v:i.lue to manktnd because t'-ie demand for them exceeds the lmuted supply. It is m this sense tha: "new" resoL!rces. other t.\an he traci:tlonal ones of agi-1cultura! land, water, and minerals, have increased in value, In tlus light urba.n. lu.1vi. is parucu1arly valuabk Just as W'! hatl to learn tc use agncu.tural land with. special regard for its q_ualitJes and the demands made on Jt, so we w1ll have to change ol.lr view of urban land. Today its use is naphazard and lar,:ely unthmkmi;: We have 'not yet learned to ask ourselves, for example, Nhether we wa.nt \O use a third. a ha:L or two thi!'d.s of our urban land for tr.e movement and storage of cars. :iow much are streets vror~h to U!Y'-u1derground, on the ~urface, aoove ground~ Equally unportant, or possibly even more 1m:,o~.i..."lt. we now have to con cewe ot Ytt another trltltal resource-: :r.e t:urc c:mensJon o: tM c:,:.-1:ie space over the urban I;mci This 1s :.zsed even :nore ha;ihazarcli!,' than the Lane itself. Just on the ho:r:zon 1s a host of problems causi:d by ele:nents compeung for th.ts limited reso1m:e-h1gh-r1se bunc:i.mgs, ,r,terbu1ld1r.g wa]11ways, l'Jghievel and aLr-eush1on highways, and private roobips, This space ove'!: th~ city is an asset that must be conserved, d.evelop.-d, anc:l used with the greatest ~arf!'. Two-{l1m~n.,. ron~l la:1du~e lonn1ng l~ ua:..~~-date. ot1.:nJ. WP urgen~j;-- ..1~ec. 1c learn how to prepare ~hree-d:mens:onal plans. -ro~, "Modo'tilZ\'119 (.,'o/b~r. Dn-~lcpme,tt" b:, H4tvt~ S l'eioff '" Dae,foh.s-s~,,,,,..., 1967, Joufflal of Occ-upetio11,czl Medidno!I 981105 MAR Ros J 37 2656