Document Ozj7530GqKN3xONkM3wdQMGov

executive ornces Keasbey & Mattisox Gompaxy MANUrACTUOCWS 01 A*0tS1O3 AMO MA0NC3IA MOOUCtS SlMCC IS*} Ambleb , Pennsylvania January 18, 1940 KfrM Ho. 1722 ciy W. V>. F. Shepherd, Esq. Turner & Newall Ltd. Spotland, Rochdale Dear Hr. Shepherd: During the course of the past three years the Keasbey & Matt,icon Company, along v?ith most of the other firms >in the asbestos industry in the U.S.A., have been financing research work on asbestosis carried out at the Saranac Labora tory by Dr. Leroy U. Gardner, and in order that T.& N. may also have the benefits of the work v.'hich is being done, I have pleasure in handing you herevdth photostat copies of Dr. Gardner's recent report and the photographs relating there / to. I a3i also sending copies of these to Mr. 0. C.: Smith at Thetford Mines. em: ck Att. KEASBEY & MATTISCN COMPANY PLAINTIFFS EXHIBIT [Af\A^t3 PLAINTIFF'S EXHIBIT Jumrn ( o- (.>" \1l0 060 06 00045 >r U The original purpose of these experiments was to r^produce in animals an advanced stage of asbestosla whose Pifogresa could be followed anatomically and in x-ray films. Tl|i ere were two major objectives - one, to establish a better c correlation between the various shadows seen in x-rays and the P4 thological changes in the lungs, and the other to determine in how far associated Infection was responsible for the severer knifestations of the disease. Upon the basis of previous experience with pure free 8 ilica, it was thought that the reaction to Inhaled asbestos W'cpld develop most rapidly if the inhaled fibres were exceedingiy fine. Accordingly Canadian chrysotilc was ground in a steel b;411 mill until practically all of the material was reduced to 2 microns or less in maximum diameter. Ihis ground fibre was placed in a hopper and churned t<j> liberate dust in the atmosphere of an 8x8x8 foot animal room. It has not been previously reported to the sponsors of the experiments and in fact the writer was until recently unaware that one volume of unground fibre was being added to every three volumes of the very fine asbestos to facilitate agitation of the notorial in the hopper. Thus there has been a li; ited amount of long fibre asbestos liberated in the atmosphere however the quantity is comparatively snull S3 the paddle, moving freely in the hopper, does not fracture much of the coarse fibre, '.he average concentration of fine asbostoa dust inside the animal cages ranged about the wall of this room has been 145 million particles per .cubic foot of air. (It should be noted that this f:.gure is 29 times that set by the U.S.Public health Service ns the maximal rcrnis3able concentration of asbestos dust in industry). Exposed to this concentration for 0 hours a day, 6 diiys a week*were 80 guinen pif3, 8 rabbits, 20 white rats and 17 cats. Peginning with the fifth month of the exposure, sample guinea pirs were sacrificed at intervals. The last group was hilled on Sept. 25,1939, thirty months after starting the ex posure. As shewn in figure 1, there is barely enough change in a thin microscopic section to be visible on magnification of 2 0? 3 diameters. Still higher magnifications (not reprod-'ced here) jveal that the reaction is not-fibrous in character, but moro cf the nature of a chronic inflammation. 060 06 00209 F'igures 2A and 3A show tho less advanced chances after etc; osurcs of 12 and 20 months' res; ectively. Figure 213 demonstrates fpr comparison the very much greater reaction obtained after a 12 months asbestos exposure in a previously reported experiment, I that instance the uvera-e a trios, heric dust. concentration was o ily about one-third that in the present experiment, but the bre was longer in that case. This exrerionce seemed to der.onstrato that, contrary to the behavior of quartz, asbestos -iust would not become more irritatin' as the size of the ; articles decreased. lliis conclusion could not be maintained, however, until it wae jr-ved that tnc ; articular lot of asbestos was ca. ble of ; roducin.- fibrosis in the lunra of guinea lifs. The only v/ay to b3 certain of this point was to try another inhalation ejq eriment aa previous experience had shovm that injection tests are not a;pilcable to asbestos dust as they are with quartz. Accordingly, in the fall of 1G3G another dust room was taken over for an experiment with uncround asbestos of the same let. After acme ex; erinentation a suitable dust, containing a high ] reportion ofihirly Ion," fibres was secured by affixing both, to "the sides of the dust hopper and to the rotating paddles r. series of steel wire brushes, -he sheering action of the o; losing sets of wires broke the asbestos into lorgths that could be inhaled. Inside the cages tho average atmos) heric concentration of fibres tk.nt could be expected to be inhaled irto the lungs was 37.5 trillion ; articles t er cubic foot of air. On Lite same C hour daily schedule 100 guinea ; igs, 20 white r.l co and G cats v:erc ex; osed in this room. T e guinea ; igs move beer, sacrificed at intervals, the last -roup boihg. killed on Povembcr 5, 1030, one year after startin'- the ex; osuros. As shown in figure 513 there is much r ore reaction to tl.e long fibres than to the finely ground : r.terl.al from, the same lot., even t.hou-h the concentration in tl.e air was only abet one-fourth as great. Higher magnifications show that ike longer fibres aro beginning to cause fibrosis lather than the chronic inf 1 amotion produced by the fine raterlal. To learn more than could be inferred from mere in spection of microscopic sections about the quantities of dust inhaled Into the lun"S, representative ;roportions have been subjected to chemical analysis. For the fine material these lusts were not started until the 12th renth of exposure,when it came to be a-predated that the anticipated fibrosis was not developing. In the long fibro ex;, eriment they were made earlier but only a few of them will be reported hero ns they have no basis of comparison. In the following figures it will be noted V x to > X 060 06 0021 that in neither aeries is the t/el-ht of Inhaled material sufficient to affect the per cent of ash very much. Magnesium silicate cannot, of course, be determined as such and the amount of available tissue in each lung precluded determination of both magnesium and silica. There fore only the latter was done. It is to be understood that in the table the S102 values are merely an index of the relative amounts of asbestos -.resent in the different lungs. The values shovm by the figures*for 1 month's exposure to long fibre as bestos begin to aji roxl: ate those for a normal guinea pig. It will be ncted that 3 or in some cases 2 animals' lungs were analysed after each interval of exposure. The results for each is given to indicate the degree of individual variation. Table w\ (n - i vw* 060 06 0021 Period Expose 1 1 mo. 8 mo. j.2 mo 15 mo Long Fibre Asbestos Dry Lung Tissue Ash Ash % S102 % S102 4.35 0.04 1.10 4.33 0.09 2.11 4.37 0.04 0.93 4.72 0.10 2.21 4.92 0.09 1.90 4.34 0.07 1.58 4.87 0.25 5.20 5.02 0.20 4.09 5.16 0.31 5.99 20 mo. 4 mo 30 mo. Short Fibre Anbestos Dry Lunp: Tissue A^h % Ash % SI 02 %S 5.fc2 4.58 5.16 5.00 4.76 4.95 5 .86 6.34 5.42 5.50 5.35 6 .55 0.51 0.46 0.54 0.49 0.43 0.53 0.85 0.90 0.78 0.78 0.96 1.27 10 10 10 9 9. 10. 14, 14. 14, 14, . 17. 19. 060 06 0021 -`t- The above figures prove th-at with both long and short fibre dusts significant quantities are entering the lungs. The comparisons at the 12 monthinterval indicate that more short fibre enters the lung than long. This of course t/ould be ex pected in view of the more ready penetration of the fine dust and the fact that its average concentration in the air was four tires as great. The proof now seems conclusive that grinding asbestos to tills degree of fineness destroys its capacity to irritate the lungs. 1. It has been shown that long fibre asbestos will produce significant changes in guinea pigs lungs within a period of one year. 2. it has been shown that on grinding sane of the same lot tf asbestos it is no longer capable of causing the same effect in 30 months. 3. It has been proved by chemical analysis that the failure to react is not due to failure of the fine material to penetrate into the lungs. 4. It has been shown that about one-fourth the atmospheric concentration of long asbestos fibres has much greater effect upon the lungs than a concentration 145 million per cubic foot of exceedingly fine particles^ Tliis evidence strongly suggests that the irritation from asbestos is not chemical but mechanical in nature. Attempts to prove this hypothesis have taken various directions. It. has been shown in a series of injection experiments that r.o fibrosis results when asbestos is injected into other organs of the .body than the lungs. Chemically active quartz, however, causes fibrosis v/herever it comes in contact with connective tissue cells. It has been shown that, in animals, asbestesis docs not ['ogress after cessation of exposure, ghe reverse is true in the cisc of chemically active quartz. The smooth covering deposited u; on the surface of an asbestos fibre that forms the asbestosis body after two months contact with the tissues would tend to nLnimize mechanical injury. It seemed probable that the lungs rat", er than the other organs should be mechanically injured by asbestos because the lungs move rapidly and constantly. To test this theory the lungs of four dogs were injected with a heavy suspension of long fibre abest03. ry means of a tube in the wind pipe, material was care fully introduced in both lungs. Then one lung was collapsed by V 060 06 00213 -5' cauterizing the Inside of Its 'stem bronchus with silver nitrate so that*lTTno longer moved In respiration. Thus we had what was thought to be effective doses of asbestos In either lung but only one would move to produoe the mechanical Injury and resultant fibrosis. The animals survived their treatment with no apparent 111 effect. A month ago two of the dogs were.killed on the first anniversary of their injection. In each case one lung was well collapsed and there were asbestos fibres on each side. Hovfever, there was neither fibrosis nor asbestosis bodies in either lung of both animals. Apparently we were misled by a report in the literature that dogs were susceptible to the action of asbestos. The result was disappointing but the method of attack seems reasonable if it can be applied in guinea pigs. V.'e are now trying to overcome the technical difficulties in volved in working with suah a small animal. The matter of species susceptibility is a puzzling feature which need not be discussed here. Hone of. the rats, rabbits or cats exposed to the short fibre asbestos have re acted. The 6 cats, now exposed to long fibre dust for 13 months, are being kept in the dust room until their exposure reaches two years before comparative x-ray and anatomic studies are begun. The guinea pig/ continues to be a reliable animal with which to experiment. While the experiments have demonstrated that it is not possible to accelerate the rate of reaction in the body, and the anticipated results have not been realized, it la felt that the effort has been extremely profitable. As pointed out in a previous report to the sponsors, they have shown the innocuousness of finely ground asbestos, which is of real practical significance. They probably explain the lack of asbestosis in the mills at Thetford. They may help to define the hazard in- other plants where very finely ground material rather than fibres constitute the major element in the dust. They serve as a guide to engineers who must control the hazard in plants,indicating that their efforts must be directed parti cularly .toward the fibrous material in the air. In view of the probability of fulfilling the original purpose of these experiments, it is hoped that the sponsors nay agree to renew their appropriation for another year. For the past 12 months the Laboratory hae assumed the obligation of operating a second dust^room for the asbestosis work.' The ex pense is somewhat over V5000. In addition it has carried on various collateral injection experiments, such as those upon the dogs and others not mentioned in this report. It has secured an appropriation for an inhalation experiment upon the Vo- *' 3-0) 060 06 00214 the effect of glass wool, which nay prove a useful control to the mechanical theory of the action of asbestos. It is hoped that you may find these accomplishments sufficiently valuable to be willing to continue the work. Respectfully submitted. Leroy U. Gardner, !'.D. lo - mSKHCifflB 2- (j) 060 06 00215