Document QMMeDykrvVZzL2x3bGpZgq247

FILE NAME: Exxon (EXX) DATE: 1951 Nov 30 DOC#: EXX012 DOCUMENT DESCRIPTION: Internal Report - Asbestos Dust - with Cover Letter c v ESSO L A B O R A T O R I E S S T A N D A R D OIL D E V E L O P M E N T C O M P A N Y J w /* -/* -* / MEDICAL RESEARCH DIVISION WOMCWT K. K C K A ftO T. H C f i , MO.tDM.C TO R N . OVt.MMCCTWO RO.MMICOKUSC,TBKM.LL.CKMVO.KtC.MC M___C_T_IO N P. O . BOX 51. LINDEN. N. J. December 14. 1951 Xr. 7. 8. Tenable Medical Department Ziso Standard Oil Company Louisiana Division Baton Bougs, La. Sear Tredt At the tine of onr infornai nesting in Pittsburgh, yon reguested that ve apply you with information on the collection and counting of asbestos dust. Trank Chorch haa prepared sons material on this subject and ve hare obtained a copy of Public Health Service Bulletin Bo. 24l, "A Study of Asbeatoeis in the Aebeatos Sextile Industry". Shis material is attached for your information. Vary truly yours, ViAa l s H. V. HBSDRICKS HVB/hp Zndi (l) 3YC Memorandum U / 3O/5I (2) PBS Bulletin Bo. 241 cct Dr. C. M. Barry Dr. E. Eanaen Dr. L. J. Bade EM00315 3 I A8BIST0S DUST CHgflSTBTt _ -V. t Asbestos is the class acne for several different fibrous minerals, but commercial asbestos Is mainly chrysotile. Chrysotile is the fibrous fora ' of serpentine and is & hydrous magnesium silicate, 5VgO.2SLO2. 2B2Q, or HgjSi^H^Op, containing bb.l per cent of eanbined silica, ^30 per cent of magnesia, and 12.9 per cent of vater. Other types of asbestos often contain silicates of iron, calcium, and aluminum, as well as magnesium. Chrysotile represents approximately 95% of the asbestos used in this country. Other less common silicates which een appear in fibrous form include! Anthophyllite (Amoelte) - (Hg.reJpSigO^iQH^ Trenalite - CapHg^SipO^)(OH)? Actinolite - iTeoolite in which Te has replaced He in amounts greater than 2$ Hornblende - C a ^ i H g . F e 11)/* ( A l . T e ^ . T O ^ S i ^ ( O . O B f e Enstntite - KgSiOj * Aogirite - KaTel n Si206 Jadeite - Ha A1 8 1 ^ 5 Vollastonite - CaSlOj Spidote - Ca2 (Al,Fe)^ (S10^)j (OH) SiUisanito - AlgSiO^ r. ,, Ccmortierite - AlaBSi^O^iCH) <. . .* .* TOXIC ITT 1 . V-..V - : T" ' i T l . .'*> ' ' The hletologleal findings, particularly of early asbestosis, does *."*4 I . 1 . not indicate e chemical injury. Gardner, as a result of studies at Saranac Imb oratory, made the following statement! 1 EH003154 I t - 2 * w * have q o m to the conclusion that iribaled asbestos fiber* are r.r irritating, not because they art Billcatet hat because they ere stiff fiber* | which nechanlcally Irritate the lane* like the free ellicas, these eincrcls ' / will not stimulate fibroblast* in any part of the bofiyj only those in the lungs are effected. It was inferred that these organs were affected because the move ments of respiration are so auch acre rapid and continuous than those of other iscera. Then it was discovered that if asbestos was ground very finely- so that few of the fibers were longer than 2 sicrons in length, the Irritating property of the asbestos was practically destroyed Inhalation experiments with such fine ehryaotile asbestos were cerried cut over a period of several years, fio fibrosis has developed in spite of the fact that an average ataospherlc concentration of 125 allllon particles per euble feet of air has been maintained. In contrast in a previously reported experiment, one-third this concentration of long-fiber asbestos dost produced well narked fibrosis after about two yenrs.* Only those silicates which are fibrous in structure have been defi nitely Identified as pulmonary Irritants. Serpentine vhich has the some ehecical composition as ehrysotlls asbestos does not cause a pulmonary fibrosis and is considered as being physiologically Inert. Tale, a hydrous aagnesiua silicate, and dlatomaceous earth, particularly calcined earth, have some clinical indica tions of having pathological significance other than benign, non-specific pneu- aoconiosis. The finding of asbestos bodies in the sputum is of considerable *" ** ' ' ^ ` . diagnostic importance. The identification of asbestos bodies In sputun can be _ done by the procedure given in Industrial Dust*, first edition, Drinker and Batch, pp. 165-166. \I , ix v... , English experience hod indicated a chenical pathogenesis for ashes- 1 t>0 03155 3 toslc. This la *t direct vnrlanoe with e^erienec in this coontry end could poe- eibly he partially accounted, for hy a difference in chenienl or physical eonposl- tlon of the asbestos. Shis variance. however, indicates a need for further study of the pathogenesis. . M/uTItSI-T ALLOWABLE COKCafTBATiaHl , She MAC of asbestos dost is 5 Billion particles per cubic foot of air, of a site fron 2 sicrons long up. Because of the l a v i s h experience, it is also advisable to hold the total count to 10 Billion particles per cubic foot of air, of a else from 5 nicrons down, COLTCTIOT OT ACT SAKPia . A Creenburg-Ssith or uldget isplnger flack is used with 2 isopro pyl alcohol as a collecting nediun. The standard scmllng rate of 1 e.f.n. ar O.lc.f.a., respectively, 1 used. s cocnniKo sa?:pl3 i The counting technique Is the light field sethod, as specified. In either "The Detemlnation and Control of Industrial Bast", Public Health Bulletin fZ17, pp. W M # , or ^Poisons, Hatards, Solvents", second edition, K. B. Jacobs, pp. lW*-lh7, with the following exception!- `TVo sinultaneoua counts ore Bade -- total particles $ Bierons and less'end asbestos fibers 2 Elcrons and larger. Great care Bust be exercised to obtain a good focus and a good light contrast during counting. Seae asbestos fibers art extrenely thin and consequently, hard to see and easily "burned out". ~ 11/30/51 EM003156 7. V, Church