Document 37Q4Lj6RN9eQJKZ04NMZjDOXE

( WlSATJi STATE BOARD CP HEALTH Adjoin, Montana DI7ZSIEJ CP DISEASE CCITBCL EXHIBIT WRG-8 A BSPQBT OH AH 2HDUSTSIAL HXGHiaS STUDT CP THE ZCCQUIE CCHPANT CP . ixrar, HOBTAKi August 8-9# 1956' Conducted brt I Benjanin P. Hake Industrial It'giene Engineer Division of Disease Control Distribution? This report, is confidential and is not for distribution except to the aanageoest of the Zenolit 3 Coapany. tv ( /\ V On August 8th end 9th, 1956, an industrial hygiene study vis Bade of th Zonollie Company of Libby, Montana, to determine If any of th* components of th* operation of this ectspary were detrimental to th* health of th* oploya Th* study was after a discussion of industrial hygiene principles vith Hr. R. A. Dleieh, Division Manager, and Mr. D. Lortck, Assistant Manager. JL V alter Baker, Assistant Plant Manager, and Mr. Ted Wright, Sepal man, ac'-ed as guides for the atudy. The present study involved the conduction of an engineering investigatic to evaluate the wording environment and by making a datermination of the enri cental factors which might have a bearing on health. Consideration was also given to the ventilation and other protective measures already is use for th* eontrol of dust and other toxic materials. The samples collected were analyzed and counted in accordance with accepted practice generally recorraanded by the U. S. Public Health Sarrice, the American Conference of Govermaantal Industrial Hygienists, and other affix agencies. Sarpicollected for dust counts were* counted a few hours after th vere eolleeted and were analysed'for free silica in the U. S. Public Health Service Laboratory in Cincinnati, Ohio. Pescri'Ptlon of Operations The description of th* operations of this company have been adequately discussed in previous reports, but,In general,they constitute sa open cut mine, a transfer point from the mine to the mill, and various milling and sizing operations dons on five floors of the company's mill, a abort distance from the sins. Th* operation, in general, la that of reducing'in also the vermiculite ore which is mined In the open cut mine to various graded sizes which are beat for the produet vhleh Is ultimately an insulatiorfmaterial. In grading and sizing, various vibrating screens are employed to obtain the sizes necessary and to reduce the amount of extraneous material from the ore. In the mining operations, approximately 17 men are employed per shift and, sixes the operation is almost wholly outdoor work, no sample-? fer dust concen trations-were collected in this area. At the transfer point from the n. to the mill, one man is employed and, although there is same dustiness, it was not felt to be significant and no samples were collected at this point. In the mill proper, operations are divided into wet mill and dry mill production. In the wet mill, dustiness is quite low; however, in the dry the dust from the various sizing and grinding operations is quite high, as noted In ths Table 1* cc Th. *r-rc=i=*u population in the-plant at the time of this study m 1 vorkers afasSat ^CCvr^rs in 19U, when the last study of the jtot wm SS! 4h?p^ulstion cf the plant a f* day* before thertu^ vae coneidernl higher but, due to a reduction in the demand for the product, one shirt was - off. Sample No. 1 2 3 4 5 6 TAKES I RTS? COBSJffRATIKB IN TKZ AS Location Description Concentration Pe. in sooef* Preiw Vet gd.ll General air sample. 11.6 Bot dt Dry sill 5th floor - General air Sample 17.9 1. (rafts Dry mill 4th floor Dry mill 3rd floor General air sample *-- General air sample 51.8 28.7 Bot ds 1.1 (rafts: Dry cdll 2nd floor General air sample 48.3 Hot del Dry mill 1st floor General air sample 83.0 1*2 (rafter Note: Composite air staple all floors provided free siliea determination of Maxims allowable concentration! Silica: High - (abort 50 free SiCb) ** 5 nppef Medina - (5 to 50% free S^O^J - 20 mppcf lot - (below 5* free S^CJfc) - 50 Bppaf Dust (nuisance, no free eilica - 50 appcf millions of particles per cubic foot of air. ConcentratIona The concentrations of duet In - - - air, as determined in table I, rarr eonai erably from a low of U.6 to a higr. -u 83 mppof. These concentrations in relatJ to free siliea are not excessive, although the concentrations on the fourth, sec and first floor were at or above the carlsm allowable concentration even far a nuisance dust with no free alllea. the basis of the asbestos content, no sti nent oan be Bade,* aince at this ties asbestos content of the dust baa not b determined. However, from visual observation and from'Informalion gained at the -2- 1 \ c jlant. a r--VE percentage increase in the asbestos content of the material p^eessad produeee several times greater concentration of &ist in the air. allowable concentration for asbestos it 5 eppef, and when the caw tion of asbestos in the dust carries collected baa been determined, furth* osnta on the concentrations will be made. At this time, however, and on t: of the concentration of asbestos found in the dust, which varies fres the c records from 6 to 22%, it would appear that the naxlsani concentration of di - thf air ahould not be greater than 25 to 50 mppcf Toxicity A review of the literature indicates that vsraiculite or th# duet fr material is not eepecially trade end is generally Included only me a miisan. dust* However, the asbestos dust in the dust in the air Is of considerable city, ard is a factor in tbs consideration of reducing dustiness in this pit According to Drinker and Hateh(^), the pathologic changes produced by tea are not like these of ailicosis* The asbestos fiber group about the nec the small air sacs in the lungs, aid stimulate the formation of s diffuse fi Thera is no definite migration or transportation-of the dust particles to th lyrph nodes and no formation of the fihrie nodules. As the fibrosis laoreas reduction in Lag area.eauses a seriate decrease in lung capacity, or dlffia la breathing. Lenta'12' suggested that enlarged hearts noted frequently la tl eases of secondary aabsstoais may bo the result of the increased work with U resulting from condition. Zt takes more work to poop the blood through ssbestotie than through the normal lung. foxinua A"nawbT Concentrations In the study of an envirotxaent from the standpoint of exposure to harm: materials, the use of maaiaai allowable coneantratinns is helpful. Marina allowable concentrations is defined as that concentretion of any harmful mate: in a working atmosphere below idiieh a worker's health will not bo affsated Adi Hudass allowable concentrations have been .established upon mazy of the eouoor dustrlal poisons snd they hare been based an the results of oorralsted engine* end medical studies in industries using these materials. Maximus allowable co trations oat in use as a criteria for the protection for the health of the wor are subject to ehange as additional information is accumulated. The eccooentrs used in this study are those recommended by tbs U. 2. Public Health Service, t American Conference of Goveniaental Industrial Hygienists snd the American Lid Hygiene Association. All naairma allw/able concentrations recorded are for pr longed exposures or those exposures for an eight-hear working day. In the evaluation of the worker's exposure to any harmful material, cog ninance of the amount of time spent by the worker in the contaminated atonephe should be taken. For this reason an attempt was made to deteralno the amount a worker spent on all his jobs where they wars not continuous. Weighted avers exposures more nearly represent a wcr~-rs actual exposure over an eight-hour d (1) Drinker, P., and Hatch, T.i Industrial Dust, `McGraw-Hill Book Co, New Tor (2) Lanta, A. J., McConnell, V. J."*w.T Pahnel, J. K.i Effects of the lnhalatio asbestos dust an the lungs of cc- itoe workers, "Public Health Reports", 5 -3 ( A** a single sample result representing an S33cure for a short portion c: A a day* concentration of eaterlol x hours a-ll*. Weighted Average* hours woriced Conc^iona and Hacocgendaticna Froa obsersztlesis Bade at the tias of the study it would appear that tsiEZ3t mechanism for allaying dust generated by the various vibrating g*cn: and othsr soring parts in the dry nil!, in particular, was well designed or: but under the handicap to which this exhaust nechnnlan is subjected It cannc dees not function properly. The follMing are several reasons why tbs dust! the dry sill is heavy and why the exhaust mechanise, as designed, does not f 1. Oust vibrates alaMt eontinuously off the rafters idiieh bars been loaded and era continually loaded with dust generating frea many sources. 2. Rubber connectors between the vibrating screens and the feed spout are sot ti^it, nor are they replaced when they vibrate off or they are worn c 3. Rubber- eenneetors lotwser the vibrating screen and the exhaust due are either broken. Biasing, or are not placed on the duota. 4. fidiaast fra some of the vibrators is Insufficient to control the < genarahed,whieh, in all probability, is caused by as over-load of the system fre other portions of the plant. 5. Backs are off asny of the vibrators, making the cduust menhenlsm * ided ineffective and, in effect, asking it wholly inoperative due to the largs fra which the exhaust draws. 6. There are easy holes in conveyor pipes in such places as stop gstas; connections to vibrating screens, and dozens of other points where holes have i cut into the pipes at xandoo locations, or idtere.tho pipes have broken by vlbn or wore through by friction of the coving ore. 7. Roods over many of the vibrators are broken, hove not been replaced are ineffective. It would appear that canvas or a resilient type cover over th vibrators would be acre effective than rigid type hoods which have been provide 8. Kmy of the transfer points fra one belt to another are not exhaust and contribute a great deal of dust to ths atmoephere. 9. Mary .of ths dead ends in ths exhaust system ware left open pernittir a large voluae of air to be drawn in through openings where no control was nsce sary, thereby reducing the control velocity in volumes of air at sore critical pointa. 10. In many locations it was rbvious that the dust collection -- was full of dirt or dust and could -r` be expected to function satisfactorily because of xuury of the reasons alreiv mentioned. 11. Many of the elevator bcujJ.-;* and screw conveyor housings are open i -4-- V- ( several places where holes have been cat for various reasons and the houain; notarial yenoved end not replaced* These elevator hewslngs and screw convey housings are particular offenders in production of dust* 22* It van noted during this study that holes were being cut is the e dusts at raarioa without any previous calculation as to the roXuae of air req or the reduction of cir volirne to other locations* The Junction* were often exceedingly rough inareasing the frictional resistance is the collection pap 13*' In sobs of tbs locations, particularly on the vibrating screens ce top floor, it is obvious that a great deal of product is being withdrawn thre the erhsuwt system by virtue of too such air being dream through the aystea ls quite probable that the reason for this pick-up of product is because of t imbalance created for the various reasons previously noted* 14* In summaxy, the foregoing points are illustrative of what would be poor policy is natters of maintenance and operation of this plant* Ifce folio lecrn mnriatlons are based on ths observations presented asd on the basis of t: dust eounta, silica content, and asbestos eaotaat of the dust* It will bo rec Bleed that the following rwccmsndaticne are particularly broad and non-epecii until such a tins as the general orwr-all maintenance and repair of existing c work, both in the exhaust systam and the era food pipes have been sufficiently repaired, no specific reeaaaendatians appear to be Justified* General reocnae tlons are as followat 1* That all of ths unnecessary openings la the entire exhaust system, ' la the wet and dry Bills be closed properly and a~ program of discriminatory cir of pipes be initiated* All aeeees doors, corners, etc*, should be provided wit tight seals and, of great practical importance, are eo designed that they are closed and secured by quiek-locking devices In place of the usual bolts and nut Aeeees doors shoald be attached by hinges to avoid the frequent damage oc when ordinarily nanhele plates are removed for inspection and aaintananee work* An objective in .designing the access should bo to make it difficult to keep the open. 2* That all of ths unnecessary openings In all of the ore transport duo and In all the elevator housings and aersv conveyors be tightly end completely olosed and that all the broken porticos of the ayatoa of the plant be wlaqustel: repaired* 3* That all of the covers an the backs of the vibrators be replaoed and Bade as air tight as possible and that ths hoods over the vibrators be repaired and replaced with a type material that will not disintegrate subject to vibratii 4* That all of the exhaust ventilation-duet work be foot by fo< end all holes plugged and un&eeessare openings, particularly at *id ends, be adequately closed and the entire eyo'-oa be cleaned of dust which has dspoeited la any portion of any of the exhaust pipes* 5. That all of the transfer mints and points where ore is being -deposit into open containers be adequately jr.cloeed and provided with exhaust ventilati< 6* That a aywtam of vanuurr.'r. Waning or other cleaning of tha rafters in the entire mill be instituted after other measures have been ***?'*% riy 5- acsonplishod 80 that tho dust loci contributed by that duit falling rsfv will bo eliminated. Pull recognition abould bo given to the fact that dime control aSosurea alone are imialuy not enough to insure safe working eonditl Tho nsthod of operations, proper naintonanee of equipaent and of houaeiceepi^ are equally essential to Maintain healthful conditions* 7* That until such tlae as the repair and naintonanee of both the a and ore conveying systoBS hove boon eoeplote, all tho sen is tho dry Bill -oo provided with and required to wear an adequate respirator, as Indicated iz, tb accocpaiying list. 8* That the opsrstors of the spray painting squlpaent be provided wit: a respirator approved by the Bureau aif Hines for sueh operation ss indicated la tbs enclosed psnphlst. 9* That it be initiated as a policy of the eenpeay to be particularly discriminating in the provisions for may boles or outlets to be cut in any exhaust ventilation duet or any ore conveying dust or apparatus and that, if any ventilation oust be provided for any process, the quantity of ventilation required be adequately determined before say exhaust capacity is taken fraa existing lines and that the result of such capacity will be ascertained on all subsequent unite whan sueh capacity has boon involved.