Document 5zgj5wQeanp663p9Gz5rXeGe

FILE NAME: WR Grace (WRG) DATE: August 8 & 9, 1956 DOC#: WRG287 DOCUMENT DESCRIPTION: 1956 Montana State Board of Health report Industrial Hygiene study of Zonolite Company ( :o:e /uta state xjar:o o? health !C'l-:.nR.> fontana DXVISftX OF DISEASE CONTROL nv-'i'ii-ca &; n,m7-i/iL h x g i e s s i m e OF TIE 20:j o u t e e a s w OF . L-IITi',, j'DrTdli G -Vf X9;E Conducted benjaain Fe l/ake Industrial Jugions Engineer Division of Diaeasa Control p'sivibut ion;.. This report is ccnfidoniiol V end in not Por distribution eeoopt to tho rannagehonfc of tko Zonolite Ctopany, o V On August oth and 9th, 1956,, au industx'ial hygiono study was taacln of tho Zouolito Company of Libby, Montana, to dotomino if any of tho components of the operation of this company x;qto detrimental to tho health of tho employees. Th study v.'a3 made aftor a discussion of industrial hygiene principles with Mr* R* A. Bloich, Division Manager, and Mr. D, T,ovlck, As8istaut Managor. Mr. 1/ alter Baker, Assistant Plant Manager, and Mr, Ted Wright, Repairman,, acted an guides for the study. Tho present ctudy involved tho ocuduohion of an ongin-';uri:<; investigation to evaluate the working environment and by malting a determination of vh onvironcontal factor's which might have c bearing on health. Considoraticn ves also given to tho ventilation end ether protective mrenuros already in uno for the centre! of aunt and other te:cie materials. The ampies collected varo ainjlyzcd and counted in accordance with accepted practica generally recommended by tho U. 3. Public Hoalth Sorvieo, tho American Conference of Qovorrcr.ontol Industrial Hygienists, and ether official agencies. Samples collected for duot counts wore counted a few hours after they were collected and were analyzed for fi-co silica in the lb, S<> Public Health Service Laboratory in Cincinnati, Chic, P .- v ij'M m o f 0' ~r:.`t ie n y The description of the operations of this company have boon adoqcatoly discussed in previous reports. but, in general, they constitute an opon cut ul.o, a transfer point from tho mini, to tho mill, and various milling and sluing operations done ur. five floors of tho company*a mill, a short diutanc, iron the nine. Thu eporatirn, in general,, w; chat of reducing in aion tho vo:mizuiii,o u..u which is mined in the open cut nlno to various graded sizes which aro beat for the product which is ultimately an insulation material. In grading and sicing, various vibrating screens aro employed to obtain tho sizes necessary tuid to reduce the amount of extraneous material, from the ora. In tho mining operations, approximately 17 man aro employed per shift and, oine tho operation Is almost vmolly outdoor v/ork, no sample1 for dust concen trations were collected in this area. At the transfox' point from tho nine to the mill, one nan lux employed and, although there is corns dustiness, it was not felt to bo significant and no camples wero collected at this point. In tho mill pro]>er, operations aro divided into wot mill and dry mill production. In tho wot mill, dustiness is quito low; however, in tho dry 111 tho dust from tho various sizing and grinding operations is quito high, as noted in the Table 1 Tho approximate population in the-plant at tho bln of this ctudy vras 100 workers, aa against 34 werkeru in 1944, when the last study of tho plant was coda, The population of tho plant a few days before tho study was considerably higher but, duo to a reduction in the demand fox* the product, one shift was laid off. . Sample Ho. . 1 2 3 4 c J TABLE I LUSr CONCENTRATI 0N3 Hi TILE A ll ?/>cetJen nlll ]\ riiH $fch flo o r Dry m ill 4th flo o r Description General a i r cample General cir Sample General air sample Ccin.cntration In miraf n, 6 17.9 51.8 Percent Frog S ilic a Hot dotonoised 1.8 (rafter sample) Not determined Dry m ill 3rd f lo o r Dry Dili ' :i f l e e r General air aample General air sample 28,7 !S3 1.0 ^ (rafter cample) XITiO/-4vj Q-5.*^.j4c-/rC-^I---IL?ii--.--... t Dry mill let floor G eneral air sample 83.0 (rafter aant; Hotel Ccupooito ai::' eun'lo all floors provided free silica determination of l.o.4' Maximum allowable Garment rations . Silicas : Dust High Medium ~ (above 50^ froa SpOo) (5 to 50% free SjO - - Low *(below freo 5^02) - / - 5 mppcf 20 mppcf 50 mppcf (nuisance, no free silica -50 mppcf lailllcna of particles per cubic foot of air. ConcentratIona The concentrations of dust in the air, an determined in table I s vary consid erably from a low of 11.6 to a high of 83 mppof. These concentrations in relation to free silica are not excessive, although the concentratlong on th fourth, second and first floor were at or above the maximum allowable concentration even for a nuisance dust with no free allien. On the basis of tho asbestos consent, no state ment can be-made, uinco at this time the asbestos content of the dust has not been determined. Howevgr, from visual observation and from information g.iinsd at tho plant, a small percentage incrocs in the asbestos content of the material being processed produces several times creator* concentration of dugt in tho air. Tho maximum allowable concentration for asbestos is 5 mppcf, and when tho concentra tion of asbestos in tho dust samples collected has beau determined, further com ments on tho concentrations will bo made. At this timo, however, and on tho basis of the concentration cf asbestos found in the dust, which varies from the company's records from 8 to 21^, It would appear that the maximum concentration of dust in the air should not be greater than 25 to 30 mppcf. Toxicity A review of the literature indicates that voraiculitc or tho dust from tfyia material is not especially toxic and io generally included only as a nuisance uat. Fiowcver, the asbestos dust in the dust in tho all* is of considerable to:d.~ cI'd,and iu a footer in tho consideration of reducing dustiness in this plant* According to Drinker raid Hatch^, tho pathologic changes produced by csbcs- tea are not like theso cf silicosis. Tho asbestos fibor group about tho nock of the email air cacs In the lungs, and stimulate tho formation of a diffuse fibrosis. There is no definite migration or transportation of tho duat particles to the lymph nodes and no formation of tho fibrio nodules* Aa tho fibrosis inoreases, tho reduction in lung gio^ cousco a serious decrease in lung capacity, or difficulty i.n..b.r.e.a.t.hing. L~a -A Guggcst1ed' t'`hat' en'larged* heart.s..n.o.t.e.d..frequent`"ly i`n t``ho cases of secondary aofccotcoia nay bo tho result of tho increased woric with tho he resulting from thin cenditions It takes moro work to pump the blood through the: asbesto!ic than tin-. nomai lurig( odr:.~\ Allowab'iu Concentrutions In tho study of on environment .from the standpoint of exposure to harmful matorlain, tho uso of uaicimun allowable concentrationa la helpful. luudcun allowable con-;-rivalids in defined aa that concentration of any lumaful material in a working atmd3phoro below which a worker* health will not bo affected adversely* kodnun all.caablo concentrations have been established upon many of tho common in dustrial poisons and they havo been based on tho results of correlated engineering and nodical studies in industries using theoo materials. Maximum allowable concen trations now in uso rs a criteria for the protection for the health of tho workars are subject to change as additional information io accumulated* Tho concentrations used in this study aro those recommended by the U. 3. Public Health Sarvice, tho American Conforenco of Governmental Industrial Hygionioto and tho American Industrial Hygiene Association* All maximum allowable concentrations recorded or for- pro longed exposures or the.-to exposures for an ight-heur working dey In the evaluation of tho worker*o exposure to any harmful material, cog nizance of the amount of tins apant by tho worker in tho contaminated atmosphere should bo token* For this reason an attempt was mado to determino tho amount of time a worker spent on all his jobs whore they were not continuous. Weighted average exposures mors nearly represent a workers actual exposure over an eight-hour day than (l Drinker, P., id Hatch, T.s Industrial Dust, licGraw-Hill Book Co, Hew York, 1954 (2) Lanza, A J., licConnoll, IA J. and Fohnol, J. W. i Effects of the Inhalation of asbestos dust on tho lungo of anbcjto3 viorkers, Public Health Reports, 50:1 of 1935* -3- - ...................................... ( does a s in g le sample r e s u lt roproconting on exposure f o r a ahort portion o f an hour 1/*'1w /'k & concentration o f pictorial x hours expose b lig h te d Av< x y hourn worked Conclusions and Rxcormr.andntlonn Frora obaeraations undo at tho t i r o o f tho study it. would appear th at t'. o . exhaust mechanism f o r a llo y in g duot gcr-xxvtcd by tho vario u s v ib ra tin g machines and other moving parte, in tho d ry m ill* in p a r t ic u la r , ims w e ll designed o r ig in a lly but uudoi* tho handicap to which t a l c cuuiauat mechanical i s su b jected :!.t cannot and c x ..j net ilr w lie u pixxcvOgg, The fo jic a d i;g c r ; c o v e rs ! reason;; wl;y the d u stin ess in the d ry m ill in heavy and vi\y the exhaust mechanism, as designed, do-ss not fu n c tio n 3 1. fa s t v ib ra te .; ;X x c jt ccriakvcounly o f f tlio r a f t e r s which have bccc:s.v loaded and arc continual ly leaded with dust gone-rating from many sources 2 Rubber cconoctcra between tho v ib ra tin g screen s and the feed spouts ore not t ig h t , nos- a re th ey replaced when they v ib ra to o f f o r they aro worn out* 3 Rubber- ccnnoetcru between tho v ib ra tin g scree n end tho exhaust ducts a rc e it h e r broken^ m issin g, o r a rc not placed on tho ducts* 4' Sxhcisfc from occ.o o f tho v ib ra to rs io in s u ffic ie n t to co n tro l tho duet generated,isvie-i, in a l l p ro b d a lltty , la earned by an o ver-lo ad o f t.ho system frcci other p o rtic s; c.-f tho plant v 5* Panes arc o f f 1x5.17 c.i tiro vibrators, making the exhaust mechanism pro vided in e ffe c t iv e a i d ,! ;, e f f e c t . a w in g i t ;;!io ily in o p e ra tive duo to tho la r g e le v a from which the adiwuwt ire.-,;; 6* There ere nary holes in conveyor pipes in ouch places as stop gates, connections to vibrating so ree ra , axdi. dosens of other points where holes have boon cut Into tho pipes at r.:vales lo c a tio n s , or whore the pipes have broken by vibration o r worn through by filetion. cf tho moving ore# 7 Hoods ever uary of the vibrators aro broken, have not been replaced or arc ineffective* It t;suld appear that canvas or a resilient typo cover over the vibrators would bo more effective than rigid typo hoods which have boon provided 8, lls rrj o f tho transfer p o in ts from one b o lt to another are not exhausted and contribute a g re a t deal o f dust to tho atmosphere* 9 lay of tho dead ends in the exhaust system uoro loft open permitting a large volume of air to bo drawn in through openings where no control vas nsccstary, thereby reducing tho central velocity in volumes of air at mors) critical points. 10. In many locations it was obvious th at the dust c o lle c tio n mechanism was f u l l of d ir t o r dust and could not bo expected to fu n c tio n s a t i s f a c t o r i l y because o f many of tho reasons already mentioned* 11 Many of tho elevator housings and screw conveyor housings aro open in ( several places where holes have boon cub for varlouo reasons and th housing mat rial removed and net replaced. These elevator housings and sere.; conveyor housings $r particular offendoro in production of dust* 12. It was noted daring thin'study that holes woro being cut in tho exhaust ducts at randan without any pecvicua calculation aa to the volme of air required., or the reduction of air volume to other locations. Tho junctions wore often left exceedingly rough inoreeoing tho iricbiomil insistence in tho collection pipa. 13. In goes of tho locations, particularly on tho vibrating eoreorc on tho ton floor, it is obvious that a great d e a l o f product I s hoing withdrawn through tho exhaust system by virtue o f too each a i r being drawn through tho cyuten* I t Jus quit probable that the reason for this pick-up of product io bccvxso o f tl.a imbalance created for th various reasons previously noted* 14* In summary, tho foregoing pointo aro illustrative of v;hab would bo poor policy in mattors of maintenance end operation of this plant* Tho follcuing recamaondatices aro based on tho observations presented and on tho basis of tho dust counts, ellicR content, and cashestoo content of tho dust. It will bs recog nised that the following recommendations oro particularly broad and non-specificj until cuch a tic# aa th general over-all maintenance and repair of existing dust work, both in tho exhaust system and tho oro feed pipes have been sufficiently repaired, no specific racoonsndaticiis appear to bo justified. General reeo tiona are as follcwci I . That a l l o f tho unnecessary openings in tho ontix-o e-ihsnct cyst-e;.-., bet!, in the wet and dry :d.Us bo c lc sc d p ro p erly and a- program o f d iscrim in ato ry cutting o f pipes bo initiated. A H access dcors, corners, otc., should bo provided with t ig h t seals and, o f great p r a c t ic a l importanco, aro no designed that they aro e a s i l y closed and cecurcd by quick-lcdclng d e v ice s in ploco of tho usual bolts end nuts* Access doors should bo attached by hinges to avoid tho frequent dcaago which occur.; when ordinarily manhole plates aro removed for inspection and maintenance work. An objectivo in designing tho access chould bo to recko it difficult . 2 , That all of tho unnecessary openings in all of tho ore transport d u c t s ' and in all the elevator housings and screw conveyors bo tightly and ccmplctoly closed and that all tho broken portions of tho system of the plant be adequately repaired. . 3 That all of tho covers on tho backs of the vibrators bo replaced and made or; air tight os possible end that tho hoods over tho vibrators be repaired and replaced with a typo material that will nob disintograt subject to vibration. 4. That p.11 of the exhaust ventilation' duct work bo exoialndd foot by foot, and all holes plugged and unnecessary openings, particularly at aaad ends, be adequately closed and tho entire system be cleaned of dust which has deposited in any portion of any of th exhaust pipes. 5 That all of tho transfer points and points xtharo oro is boing deposited into open containers be adequately enclosed and provided vd.th exhaust ventilation. 6 That a system of vacuum cleaning or other cleaning of tho rafters In th entire mill bo instituted after the other measures have boon adequately ( ( accomplished act that tho dust load contributed by that dust falling off raftoro will be eliminated. Full recognition should ba given to tho fact that direct control measures alone aro usually not enough to insuro oafa working conditions. The roothod of operations, proper maintenance of equipment end of housekeeping are equally essential to maintain healtliful conditions* 7. That until such time as the repair and maintenance of both the exhaust &nd ore convoying systems havo boon complete, all tho man in tho dry mill bo provided with and required to near an adequate respirator,, os Indicated in tho eecasparylng lint, 0. That tho operators of tho spray pointing equipment bo provided with & respirator approved by the Bureau of I-LLnes for ouch operation as indicated in tho enclosed pamphlet* '9* That it ba initiated as a policy of tho company t o bo particularly discriminating in tho provisions for any holes or outlet to bo cut in any exhaust ventilation duct or any ore conveying duct or apparatus and that, if any ventilation must bo provided for any process, the quantity of ventilation required ba adequately determined before any exhaust capacity is taken fren aviating lines and that the result of such capacity will be ascertained on ell subsequent units when such capacity has boon involved.