Document jynQEXy0MYXVNvjz73vXDe7p

FILE NAME: Asbestos in Plastics (AIP) DATE: 1975 Dec DOC#: AIP004 DOCUMENT DESCRIPTION: Trade Journal Article - Handling Asbestos: Chrysotile Asbestos in Plastics JOURNAL OF PAINT TECHNOLOGY - . Asbestos C h ry s o tile / *j" T'^&fy'k- A s b e s to s in P l a s t i c s _ ,' *.-4i** r-\laV>ftitl'/Sfci'.; * * sH. *s r f z i V. Ms.iw''*-?tsi f5. -4 Asbestos has received .great deal-of attention and publicity in recent years especially after it was designated a "target health hazard" by OSHA and a "hazardous air pollutant" by the EPA. Many of the articles on asbestos by the press have been emotionally oriented or distorted and, in some cases stories have been sensationalized, based on obvious misinterpretation of facts'. The use of half-truths or unsubstantiated statements has led to general con fusion and the unfair castigation of asbestos and products containing asbestos. The purpose of this paper is to put the matter of asbestos use and asbestos hazards into a logical and practical perspective. In this paper, the different types of asbestos and their many uses are discussed, along with government' regulations controlling the use of asbestos. .The health hazards associated with asbestos, both occupational and environmental, and some industrial experience with air sampling and dust control^measures are also covered.'. . in {*}'CJiCi 3 *!"***: u ' --'sli *,?xr " *] *'"'*--*'* cT--*..'. - KEY WORDS: Asbestos; Plastics; Air pollution; .Toxicology.^ ,, vC-`w < .. , t" ' ' VJV/tV ^ floor tile and in phenolic_m olding compounds. I t is abo used in other plastics such as polypropylene, poly ester, nylon, m elam ine, epoxy, ribcone, and v in y l Asbestos provides a valuable function in such products as . b rak e linings, d u tc h facings, electrical: ^components, autom otive partspiunu--. *ture, boats, sealants,' coatings,'adheriv es,and m astics. T he most im portant - functions of asbestos in plastics are re inforcem ent, dimensional -stability, h e a t resistance, flow control, and gen- , eral-puipose filling. Most of d ie func tions a re su p p lied : b y ' short-fiber chrysotile - asbestos' fiber,* although What is A sbestos? Asbestos is a commercial or generic ten n used to describe six naturally occurring "ashestiform" m inerals d u t are fibrous, hydrated m etal silicates. T he fix varieties are divided in to tw o classes--serpentine . and am phibole-- biased on their crystal structure. Chrysotile is the only m em ber of th e serpentine class, w hile the am phiboles include croddolite, am osite, anthophyllite, trem olite, and actinolite. Chrysotile is by far the m ost-used variety and accounts for over 95Z of U.S. consumption, as noted in Table 1. C roddolite, also known as b lu e as bestos, is im ported from South Africa. Because of its high m echanical strength and good resistance to ad d s and alkalis, it is used to reinforce a lim ited variety of plastics w here its pronounced color is not objectionable. Amosite. also im ported from South Africa, is used prim arily in therm al insulation. Although there are some deposits of anthophylHte in th e U.S., m ost of it is im ported horn Finland. longer chrysotile fibers and other as bestos varieties are sometimes re quired for particular properties. I t is used prim arily as a filler fo r- . polypropylene and in insulating m a Why Use Chrysotile? terials., A com parison o f th e four - ' Among the several advantages of '.-varieties of asbestos w hich exe at com-. , chrysotile, `which set it ap art' bom m erdal im portance is p resen ted ./in '] ; -the am phibole minerals and aocount Table 2 . I t should b e noted th a t th e re ' are significant differences betw een chrysotile and am phiboles w ith regard to chem ical com position and certain physical properties. . , - for its w idespread and increasing u s age, are w orld-w ide availability] m e chanical strength, flexibility, positive surface charge, low iron content,'.soft ness, and low refractive index. I t is conservatively estim ated th a t chryso- - .. Where is A sbestos , Used and Why? ... . tile asbestos is used in over 3,000 ap , plications and, in most of these appli cations, it is an essential ingredient Asbestos has served mankind for for w h ich 'n o replacem ent is readily more than 100 years in a broad vari available. ' ety of applications. T he genera] areas T he inform ation in Table 1 shows in w hich asbestos is used in th e "U.S. th at d ie use. of chrysotile asbestos and are shown in Table 3. Based on infor mation from asbestos producers and its share of th e total m arket are stead ily increasing. T his is due partly to consum ption surveys, it is estim ated technical advances perm itting die th a t die plastics industry uses about broader use of chrysotile in plastics 33* of th e 800,000 tons consum ed an and die general decline in d ie use of nually, w hich makes it d ie largest asbestos in certain fireproofing and in Fmentcd *t the Golden Gate Society' M in. atement Seminar held in San Fnmcnco, Calif., June 16. 19)5. * Metal Div,, Kiaaan Fall*, N.V. I4S0S. single user of asbestos fib er.. The largest uses of asbestos by die plastics industry are in vinyl-asbestos sulating m aterials. In addition, there b increasing evidence th at croddolite and am osite are m ore hazardous to Vol. 47. No. 611, December 1975 4 s' Year 1967 1968 1969 1970 1971 1972 Table 1--Apparent U.S. Consumption of Asbestos, Tons Total Chrysotil* Amoslt* 720388 686,044(95)* 12358(1.7) . 817368 . 775,711(95) . 20,467(23) 784321 , .V*. 749,708(96)-^; .14318(13) J 728,181 - - 695,770(96) y . r - ^14361 (23) *?- # *-- : '* " 729372( 9 Q ? r i ^ ,-14380(13) (a) lnlormation Bureau of Miner* 1 (b) Pen*: - C roddolite 14317(2.1) 18,965(1.7) 10358(13) . 8386(13) 6,953(0.9) Table 3--Apparent U.S. Consumption of Asbestos By General Use Areas Arm of Um Portent of Coniumption Construction ' 7 Floor tile * ' ..; ' Felt paper - ' . Friction and 40:7, IS^7,f^i:. ........ ' .* Insulation 4 0 ,^ * Textilei ` . * ___ - . -" ..s ,; * .11 V V'*- huuimsnauni uhwea"l"th than chriy-s-o--t-l-le.*J " . 1970, the use of croddolite in Britain Jfl,er im portant 0 0 ^ ' Research on Cancer (a d iv irio n o ffl has been restricted after a panel of experts "concluded there was sum- ' i S c S - f f i S dent evidence to suggest other types S f t i s a s of fibre should be s u b stitu te d ^ croddolite wherever po8sfble."V^` ;; reported th at:. I t seems clear, m en,.. T he e v id e n c e je -1- . V 4 [ ; ; that lung cancer is unc?iran^ "?"^ ' iates t0 conditions of rn^ yersago. asbestos insulation workers who.have What i$ the A sbestos Hazard?./.,, ud _Th. ere i,s evi-de_n_ce^of n o excess -nrslkc . It is readily accepted that asbestos, ' ^ risk .is increased, such in of mesotheliomas from asbestosTate pollution w inch has estod T n jtb e like many other foreign bodies,-oan ^ .rre a re is not g r e a t '^ ^ ^ ^ 1^ ' ^ ^ ^ ' _,a .L U Ju )''n ( lmsa6Ie*ii3 sm o-j cause dkabhng m onaiy fibrosis), '^nato m ines.-T here are report m n e r-r.. ^m ore i cen tly ,:been . a ^ a t e d ^ t h ^ ^ h id d e n a bf,meso&3k)ma - to asbestos. This W e and ;to asbestos' M e so -^ m h ^ ` aha rural are as,.A e ; i bronchogenic carcmoma (lung can- . ;theljom il -n an extrem ely rare oaneer ;:;aaj9ts 0f w hich h ave not been estab-. cer) are the tw o m ost common a s bestos-related diseases. It is im portant to note th at, based on epidemiological data, these diseases , have occurred , prim arily in workers w ith high, long* < of the lining of he chert (pleura) or " , ^foere is no evidence of a risk r the abdominal cavity (peritonema). . .- ^ ^ general public a tip K a e n t^ fo s ' In contrast to the lung iseaaes,-there..':,.. 'V , .V_^_ v -. , is some evidence diet m e s o fte W - T t e ifT p S can occur after brief exposures 4o Iso concluded that mere is. at prw- - term exposures to aibestos dust. I t is of fu rth er interest th at one noted .re searcher has reported th a t neither of these diseases is peculiarly related to - According to the 33-member Ad- visory Com m ittee on Asbestos Can- 1 -iC - ** * t ;- '*** SiuJDc.hReuvn.id, ie"nc_"e_av_suet--h--e--r.-e--is* doeswnu-o tum,u - , dioate any risk of cancer resulting from asbestos fibers present in w ater. - Formula Table 2-- Comparative Data for Asbestos Minerals T ' / * - i. -- rkrwotti* Croeidolite Amolte AntHophyllit* 3Mg02Si03'2Hi0 No,O F*,0 . 1.5M905.5FeO 7M o0 8SIO.*H0 .V ..*.* 8SiO, H,0 BSiOi'HtO 3Cnca. ^->Jr* Composition % SiO, Mgo .... FeO .. 4 . F e.O . ' A1,0^ H ,0 ............ CaO ' .. N a,0 ` *"'' . CaO+Na-O " Crystal! . .. . Color . - Texture . Flexibility Hardness, roohs Fiber diameter, A Tensile, mp*i . . . . Surface charge . Resistance to add Resistance to alkali '87--44 ' , 89-44 0--6 ' '. ,70 -5 ` ' 0 -2 . ..,, 12-15 _ _ "0--5 ,4 - - *' ",* ,`'" . Fine fibers Cray green Soft silky very good 234 180.300 800 Positive Poor . Good .14, 49-58'*' r *49-58 o -sr 18-20 -- 84-44' 17-20 . ' ' m> **- . 2 -9 2--5 . -- 4 -8 . 7.,---)2.AS.18-,' , --- i:-"rv; o 8 : Brittle fibers Blue , 'I Harsh ; . Good , ; ; 4 600-900 , . 600 , - N egative../ Good Cood .. ... . Prismatic Gray/brown Harsh .. 534 G o o d -. - 600-900 .200 . , Negative . Cood Fair . .. ., 86-58 28-434 T. 3-12 0 -2 Prismatic Gray Harsh Poor . 53-6 . 600-900 .,< 4 ' "'S** Negative-. Very good Good -- -- Mod Fbato Sncrdopedia 97. and EnnctepedU ^ Cbe- Tech Vol. S. beverages, food, or in the fluids vA ^ ' for A e adm m istratitm m . v W hile there seems *o b e g eieral ' agreem ent th a t e public is motj n : cany present danger from asbestos, it is also recognized th a t excessive,Toog- term occupational exposure can cause -serious health problem s. A h o .Ifm n - m ade emissions are not controlied, * e ri ` environm ental cxmtamsnaboo could could approach harm ful levels. D uring rite p ast two years, significant legislation has been.enaC ted by the Federal government to reduce and control occupational exposure to as bestos fibers and to m fariim fiber emissions to die enviromnenV Addi tional standards or regulations have been proposed ,o r enacted by* massy states an d local governm ents.*-^ ' . r is tf /i'j ''/ Summary of OSHA Regulations i'!' T & ^ W fllfam -Striger Occv^abonal Safety and H ealth Act of 1970 b e came effective on A pril 28,1971. w ith the follow ing Congressional purpose: Im proper inteipretation of die reg EPA Standards "To assure so far as possible every ulations has created m any miscon W hereas OSHA is responsible for working man and woman in the na ceptions about equipm ent and pro the protection of the worker, the En tion safe and healthful w orking con cedures needed to properly use vironm ental Protection Agency (EPA) ditions and to preserve our hum an asbestos. If exposure lim its are not is charged w ith improving the en resources." The Act established the exceeded, -there are no further com vironm ent to which the general public O ccupational Safety and H ealth Ad pliance requirem ents except fo r med- is exposed. On March 31, 1971, as- m inistration (OSHA) w ithin the D e- ical examinations. M edical exam ina ` bestos, along w ith beryllium an d p artn e r of L abor, w hich has re- tions arc required fo r all employees . ' m ercury, was identified a s . T n a u d - ' sponsibifity' fo r adm inistration .and in any occupation exposed to.atibm e ,v ' oils ir pollutant" by fi Admdnistra- T enforcem ent Research and ~rela ted . am centrations of asbestos flte ts./Ilie / lo r .o f th e E P A ..'N ational E m ission,.. functions are handled by d ie D epart-;: examinations a re relatively sim ple and />".Standards for asbestos w ere then pub- ' m ent of H ealth, E ducation and W ei-'' " shoMur*l,*d:, *c<os*tn,om morJei t t>Ath`an $5 Va 0a .i t pe.>r .>..: lished b y EPA in die Federal Regie- fare (H EW ) throutfi th e N ational?* ' ' 1^ e` ' ter, Vi. .38, No. 66, A pril 6, 1973. - In stitu te of Occupational Safety and ` Respirators an d sp e c ia l. clothing A lthough no num erical emission sten- - H ealth (N IO SH ). Five million em are required in d ie construction trade _ dards w ere established, -operating eri ployers and 60 million of th e nations for d ie spray application of insulation " terra 'a r e prescribed,; to prevent ' or - . 80 million workers are covered by .and fireproofing m aterials, an d fo rth e lim it asbestos emissions to -the out- ; OSHA. Specifically occluded from 'rem oval of such m aterials. T his spe- side air from asbestos mills,' roadways, - coverage are government employees d a l protection is -not required for any certain m anufacturing operations, and operations which are protected other use asbestos unless exposure building dem olition, a n d th e spray-on under other federal health and safety, lim its a re exceeded. T his is also true application o f m aterials used to i n - r laws. In a news release issued January fo r Jo d ier Item s such as specially sitiate o r fireproof equipm ent an d 4, 1972, OSHA announced a T arg et- equipped tools, change room s, clothes m achinery. The law fu rth er requires . H ealth H azards Program .aim ed a t - laundering,'and .w aste disposal., Res^ th a t spray-on m aterials 'u sed -to in-;, im proving health factors associated >;<"pintora a re n o t a su b stitu te fo r en^ ^ su late or fireproof buddings, struc w ith w orking conditions. T he follow- -1 gioeeriiig ^controls, b u t the Jtrw.allows / tures, pipes,ind conduits shall -com . ing five substances w ere designated their .use w hile controls ^aire T jeing ta in less th an asbestos p it-a d ry - to be d ie focus of initial a n d co n -' im plem ented, in ` p e d a l. situations . w eight basis. This should significantly oerted efforts by OSHA an d N IO SH : w here controls -ar . not /feasib le or reduce emferioins^to -which die gen-, asbestos, cotton dust, silioa, lead, a n d adequate, in em ergencies, and forin eral p u b lic m ay be'exposed, especially carbon m onoxide: ":. ' . *=> . frequent short-term . job. assignm ents. in large urban areas, ?. " - -, A t die p resen t tim e, new standards have been established only for ades- Caution, labels a re required on prod- : th e Administrator (o f EPA) nets containing asbestos except w here has determ ined that, in order to p ro tos, although, of die 8,000 toxic sub ..tiie fibers have been modified by a vide an am ple m argin of safety to stances on th e NIOSH list, only 500 bonding agent o r other m aterial to protect d ie public health from as are covered by standards and m any prevent dusting during any normal bestos, f t is necessary to control em is of those need updating. The new subsequent use or handling. Besides sions from major man-made sources Standard for Exposure to Asbestos D ust was published in d ie Federa1 Register, V o l 37, No. 110, on June 7, raw asbestos fiber, products which require package labeling could in clude: dry acoustical spray products of asbestos missions into d ie atmos phere, b u t th a t it is.n o t necessary to prohibit all emissions.',i --S-y' v 1972. T he basic exposure standard is and joint cem ents, unsaturated roof- . "In th is determ ination,"die Admin- an 8-hr tim e weighted average ing f e lt;and textiles, and some in istrato f has relied on die. N ational (TW A ) of five fibers, longer than 5 sulating products m ade w ithout ade- A cadem y f Sciences' -report o n .as- ;, : m icrom eters, p er cubic centim eter of quate binders. T h e labeling of a p ro d -. bestos, w hidi concludes: " Asbestos -is air. T he TWA lim it is to b e reduced u d does n o t prohibit .its -u s e . I t ` too im portant in our technology -and. to tw o fibers p er cubic centim eter on ' should b e noted here .th at in a t least economy fo r its essential use to b e July 1, 1976. A peak concentration of 10 fibers p e r cubic centim eter is not to be exceeded a t any tim e. All of the fiber concentrations are those to which an employee m ay b e ex posed w ithout protective clothing and equipm ent. T he first basic require 90S of the products containing as bestos. die fibers are solidly locked into -the product thereby presenting little danger of dust generation dur ing norm al use and handling of die product* ili--;.-,.- ' '.'.r-;--. stopped. B ut, `because o f th e known serious effects of uncontrolled inha lation of asbestos minerals in indus try , and uncertainty as to the shape an d character of the dose-response curve in m an, it would be highly im- m ent of d ie new standard is m onitor ing to determ ine w hether or not fiber concentrations are in excess of die exposure limits- Some asbestos sup pliers provide a monitoring service to custom ers, and a sim ilar service may b e obtained (ram state health depart m ent officials, insurance carriers, or private consultants. T he k w requires JOHN L. MYERS. Marketing Manager for the Calidria Asbestos Group in Union Carbide's Metals Div., received his B.S. Degree in Chemical Engineering from Purdue University in 1951. Joining Union Carbide that same year, h e served In the Nuclear Division until 1966, w hen he be came a Research Engineer in the asbestos group. He was promoted to his present position in 1970. . . . : th a t m onitoring b e repeated as nec essary to ensure th at employees axe not exposed to levds m excess of die exposure lim its. ... - : Vol. 47. No. 611. December 1975 prudent to perm it additional con tam ination of the public environm ent w ith asbestos. Continued use a t m in imal risk to the public requires that the m ajor sources o f man-m ade as bestos emission into die atm osphere be defined and am tro D ed .* ,^ -,:^ --^ v .;'" -?.*a ** . yWtat is Industry D o in g ? t^ v |t Table 4--Typical Air Sampling Results* . Celling . Type-Plant - Concentration, Or Operation Asbestos F ibers/ >3. .Phenolic com pounding^ Dust-Control Measures Asbestos producers and users are spending a considerable am ount of tim e and money on various dust-con trol measures. Conventional .means to achieve minimum dust levels include: ventilation systems on process local -ventilation'for saws T he Asbestos Inform ation Associa- ' - Gypsum compounds -^T/w e tte d " operation, Irak-proof ;paek- aging,' vacuum clean-up,- m ore care in tkm /N orth America reports that, dur ing die p ast 30 y ean , th e asbestos-in ------ I*"Y "' -* (a) Source: Union V' Carbide Corp,, '-i tram air . '* bag disposal and other asbestos wasted monitoring reporta ~'r~* . ;,v>`. ^ mCv ' handling, arid autom atic bag' openers. - dustry has spent m illions o f dollars to - "Unusual innovations Include: ! pel-' im prove mining, m illing, and m anufac =*- letized asbestos, special packaging, turing methods.* T he establishm ent of if.. and treated products. safer working conditions has been a _ - Only short-fiber duysotile is -avail prim e ta rg e t and this work continues able OSHA level is 10 fibers/oc. 'In . able as pellets, b u t this product serves unabated and in close association w ith most cases, th e TWA exposure level -, `_a__f_a_ir p o_r_t_io_n__o_f__th__e_.a_s_b_e_s_to_s__m_,_a_rk__et governm ent agencies an d independent w ould b e w ell below OSHA>stan- r" ^PeHetsm ot only reduce dust during medical researohers^-'w^'t^t? " ' dards. M ost of the data w ere collected ^ `7'conventional handling b u t ih ey -n re- T h e ultim ate goals of the asbestos before -the Installation:* bulk hopper c a rs a n i: industry are: Reduction of work-area dust-control m easures: M onitoring T xariT transferred and used in totally dust to minimum, levels; Protection -enclosed systems,.Barring leaks in A e ' of workers from asbestos-related dis ditions -are caused Try m aterials other-*"- Tsystem,-riust in work,areas is virtually - eases; M aintenance of environm ental ' fhari asbestos.This does riot preclude - " eliminated. T Jsediin t buIk, .usbestosl emissions a t levels low enough to p re -', th e n e e d for controls^ "but "It riould * pellets-also reduce - shipping-boosts,', d u d e public endangerm ent.' .' ' iU i (range their scope end facilitate corn-', ; .-warehouse''.,storage^ end. - ' * pliance w ith governm ent regulations. "handling, -facilitate autom ation, reduce.' Air Sampling. V:-Z-,' In order to com ply w ith OSHA standards and to determ ine th e need for dust control measures, air monitor ing should b e conducted in areas w here asbestos is regularly handled or used. OSHA standards require th at "all determ inations of airborne con centrations of asbestos fibers shall be m ade by the m em brane fiker method a t 400-450X (m agnification) (4 milli m eter objective) w ith phase contrast illum ination."** The eq u ip m en t. for collecting, a ir samples .costs less than $400 and is readily available. A phase contrast microscope can be obtained for as little as $600, or an existing microscope can b e modified for "counting" th e asbestos fibers m com pliance w ith NIOSH criteria.1* . Air samples have been collected and analyzed on a regular basis by the asbestos industry for yean. Ex cept for a few applications w here dust control is an engineering problem , in dustry is finding th at dust levels are already w ithin acceptable standards or- th at minimum changes are nec Because of "b ad press?* asb esto s'is clean-up, an d elim inate b ag handling frequently ordered o u t o f use w ithout .and disposal. T h e pellets-contain ,no . regard to w hether -or rio ta ^ h a z a rd v h in d er and are-friable rinough to b e actually exists /due `to a ir -contamina'- dispersed in dry form .or.h i aqueous ' tion. ~ If acceptable dust levels are or resinous'.systems w ith conventional feasible, th ere ti rio need to replace ' high-shear grinding equipm ent." asbestos a t the expense o f product . Several types of special packaging quality or economic penalty. Gordon are currently available, and suppliers E verett of EPA points out th at in- ~ consider custom er requests for--unus farination on th e biological effects of ual requirem ents. T he floor tile indus asbestos is very lim ited and th at the try can obtain asbestos in plastic bags effects of many substitutes have not w hich can b e added directly to ,the! been investigated a t a. Before as com pounding operation. Asbestos - in . bestos is replaced, it should h e cer bleached paper bags assem bledw ith tain tirat a sa fe r alternative is'av ail- w ater-soluble glue and printed w ith ' a b l e ? * ? w ater-dispersible Jnk: ran .be -added ' ' Obviously there are ' m ore p eo p le, f .directly to paper-m aking finishes x exposed to products containing ashes- acoustical tile formulations. jW j* tos than d iere re to raw asbestos' " ; A lthough "w etted" asbestoses not fibers. As noted previously, more than 90% of th e asbestos used in this -coun try is in products in w hich the asbes tos is "locked in" -or bound -with ce - roent, plastics, o r other binders, so ..th a t there is no release, or a t least no significant release, of fibers in work areas or to the environm ent M aterials or products w ith kxkod-in fibers w ould include: floor tile, polyester generally . available, .most . suppliers are working -with customers to pro vide "dustless" products. W hen justi-. fied by m arket demand, asbestos can be treated w ith w ater, m ineral spirits, , glycol, or other m aterials com patible w ith the application or system. c ; .. * . ;*"*. ^' *:r . z: crvr.i^ . Conclusion r essary to achieve com pliance. Al resins, phenolics. sealants, oatings, Asbestos is one of inJusby*, m an^ though data on many asbestos/plastic brake linings, friction m aterials, ru b raw m aterials w hich, involves a po applications are not available, the ber, roofing compounds, and rein tential hazard_w hen not used w ith summary in Table 4 is typical of our forced plastics. Since an abrading ac reasonable respect and care. Although measurements of dust levels during tion o n some of diese products could all forms o f asbestos are recognized asbestos handling in various types of release asbestos fibers, appropriate as hazardous to health when Inhaled plants and operations. T he dust levels m onitoring an d /o r control measures excessively, there is growing evidence reported are ceiling concentrations, should b e instituted if it is thought th a t croddolite and am osite axe more and it should b e noted th at d ie allow- th a t such action w ould release fibers. hazardous than chrysotile. Fortunate- Jy, the plastics industry uses prim arily chrysotile asbestos and, in m ost prod* ucts, th e fibers are -locked-in to pre vent airborne contam ination. Al though asbestos dust levels are gen erally low er than expected, industry continues to expend large am ounts tim e and m oney to fu rth er im prove th e quality o f th e workplace^ A l though th e general public is n o t cur-; rendy in danger, occupational controls are required to prevent future vironm ental contam ination. " ...... - ~ fc- Chrysotile asbestos and necessary raw m a te ria l,--------- th e nation's safety and economy; and, , __ Vr;`\ w ith proper control, it can h e used * * " safely and in com pliance w ith govern m ent regulations. M edical, scientific,' governm ent, and industrial personnel ................ m ust continue to w ork ckwely V gether to establish reasonable e a q ^ . ^ v '^ '^ r::.-vr J-V--V sure lim its, provide safe -work ' ."sc .-s- >.Yy v.r' ..v 'vi & i datd, (4) Hammond "Relation Risk ated Worker at meeting of the Working Group to Amen Biological Effect of Asbeitot. International Agency for Re- earch on Cancer. Lyon, France (Oct. 4, 1972). (5) 'Report of the Advisory Committee on Asbestos Cancers," Brit. J. In- dustr. MeiL, (6) "Asbestos,' (Oct. 9, (7) "National Hazardous Register, 1979) (8) "Protecting the Asbestos Worker," Booklet No. 101DS7, The Asbestos Information Astoriation/North America, p 5. (9) Selikoff. I. J.. Industr. Medicine, 39, No. 4. 21 (April 1970). (10) "Standard for Exposure to Asbestos Dust," Federal Register, 37, No. 110, 11920 (June 7. 1972). (II) Bayer, S. G., et al, "Equipment and Procedures for Mounting Mflllporc Filters and Counting Asbestos Fibre* by Phase-Contrast Microscopy," Bureau of Occup. Safety and Health, U J. Dept, of Health. Edu ?cation, It Welfare (Feb. 1969). (12) "Asbestos Health Question Per- ilexes Experts," Chem. Eng. News, 8 (Dec. 10, 1979). - (IS) Myers. J. L.. "Caildria Asbestos Pel lets," ASBESTOS (Oct. 1971). Vol. 47, No. 611, December 1975 *" ' :-;s; '<*v --- V" Sjt? . t'str^ Asbestos Information Association North America - ^ 1660 L Street, N .W .-:-> Washington. D. C. 20036 .