Document kDv95jQbR5rG72QJpR7a16doE

1 j oonalo d. )HAASE. M 0. J THOMAS M.. <CLIFFORD. M.O. PETER Y. LEON A ROSC N. M O. SILVER BAY CLINIC. Lto. so outer onive SILVER BAY. MINNESOTA 35614 PHONE: (218) Z2G-443I July IT, 1973 KfUtiVcO JUL2C 1973 E. f. F. j Mr. Edvard T. Fride 1200 Alvorth Building . Duluth, Minnesota 55'202 J Deal* Mr. Fride: I have had an opportunity to review the letter from Doctor Roy E. Albert to Joseph Padgett of the Environmental Protection Agency. I have also reviewed the enclosed draft report by Philip M. Cook. Fa.D. entitled "Assessment of Potential Environmental Health Har-rd Associated with Airborne Mineral Fibers Emitted During Taconita Ore Processing". My field of interest is clinical medicine. For the past 21 years I have also served a: medical consultant for Reserve Mining Company at Silver Bay, Minnesota. I hava race ar xhaustive review of the literature concerning asbestos and I have attended multiple symposia concerning this problem. My comments will largely be directed to the draft report of Doctor Philip Cool-: in :c that I feel some of his statements are either inaccurate or incomplete. Doctor Cook states that since little or no epidemiological or animal study data evisto which can be applied specifically to each occurrance, this assessment often depend.- nr. comparison of physical and chemical properties to asbestos on comparison of airborr.: fiber concentrations to concentrations associated with asbestos disease. However, .. case of Reserve Mining Company, many studies have been conducted which pertain to -. potential carcogenifiity of particulate emissions. In 1976 Smith et al (l) pub11 . conclusions of a Hamster Ingestion Study using Reserve Mining Cc_.pany tailings. t unable to show any evidence of carcinogenicity due to the feeding of tailings. ' : r ; Harrington (2) con'.ueted an epidemiologic survey utilising 2~;0 senior c.v.puoyees of Reserve Mining Company. These individuals were people who aver . ASARCO ALV 0002662 2- - experience with the company. They concluded that the 3CO individuals chewed no x-ray or respiratory abnormalities in excess of the general population. Confirming evidence of this thesis was added to by McDonald et al (3) in 1977, who did an epidemiologic study of gold miners exposed to cummir.gtonite-grur.arite fragments. Again no excess of lung cance vas found among these miners. The entire Reserve Mining Company work force is folio-wed annually by chest x-ray and physical examination. Since the beginning of the Reserve Mining Company operation Doctor Leonard Bristol (h) of the Trudeau Institute has followed all of these x-rays. He has found no evidence of asbestosis in any members of the entire mining group in the past 2? years. In a special study in 1975, Doctor Russell Morgan (5) of John Hopkins University vas asked to express his independent opinion concerning x-rays of employees of Reserve Mining Company who has over 15 years mining experience. Doctor Morgan reviewed approximately 960 employee x-rays and found no evidence of asbestosis. Recently the National Cancer Society (6) did a study in Duluth, Minnesota and has express ed the opinion that there has been no increase in pulmonary or GI cancer when compared t' the TJ. S. population. The Minnesota State Department of Health (7) developed a survey utilising death statistics and has found no increase in pulmonary or GI cancers in resi dents living in the area of the western arm of Lake Superior when compared to the Minnesota population. Furthermore, each employee of Reserve Mining Company is examined annually. After 21 years of such physical examination, during which time I personally have probably examined every senior hourly employee, I have found no evidence of asbestosis such as basal rales or finger clubbing. The conclusion is that studies pertaining to animals and more importantly to humans exposed to Reserves particulate environment have demonstrated no relatablc adverse health effects. Doctor Cook quotes a study of underground.miners in a gold mine with grunerite fibers as having demonstrated a three fold excess of respiratory cancer mortality. He neglected to $ point out that that study (o) contained several serious flaws. First of all the group chosen for the survey was n small select group. Second, the number of respiratory cancers tallied in the survey actually were not all within the respiratory system, Finollv. there ASARCO ALV 0002663 was no evidence for asbestosis in these miners presented by the author and it is a vilely understood fact that increased lung cancer in asbestos exposure occurs only in the pre sence of asbestosis. Doctor Cook states that animal experiments cannot provide absolute effect fibersize relationship since asbestos samples of uniform fiber size have not been prepared. This statement is not correct. In 1976 Wright and Kuschner (9) prepared crocidolite and fluoranphibole fibers by synthetic grovth. These fibers then of dimensions suitable for experiment were then administered to guinea pigs by intratracheal instillation. The net result of this experiment vas that fibers over 10 microns in length consistently produced lung fibrosis. Fibers under 10 microns in length consistently produced little or no re action. In 1972, Stanton and Wrench (10) issued a report concerning mesothelioma induct ion using chrysotile and fibrous glass and came to the same conclusion, that is that shorter fibers produce less reaction. Morgan (ll) concludes that there is an accumulating body of evidence which shows that the fibrogenic activity of asbestos is associated with a long, rather than a short fiber. In a 1977 report to the Society of Occupational and Enviror_-.a-.ta Health, Doctor J. M. G. Davis (12) concludes that the long fiber theory of asbestos patho genesis, especially carcinogenicity, does at the present time appear to be correct. The statement is made that pulmonary tissues of asbestos workers contain many more-short fibers than long with an even shorter fiber Gize distribution in pleural tissue. To support his thesis he quota the paper by Bignon and Sebastien (13). However, at the meeting in Washington, D. C. of the Society of Occupational and Environmental Health where Doctor Sebastien presented his report verbally, he made it a point to state that fibers as long as 2G0 microns have been found in human lung tissue. Consequently, fibers of carcinogen!: site are found in tissues. . octor Cook states that the environmental cgcncics animal tests are being coni', Reserve Mining Company nmphibolc fibers which are representative of fibers four samples from Silver Bay. Tills statement is not true. The fiber s used in that ASARCO ALV 0002664 . It - collected in an area adjacent to the mining pit at Babbitt, Minnesota* They represent a' atypical long fiber sample which is not in the mining area and which will never be included in the mining area. A letter written by Mr. Matthew 3anovetz(N, )the executive vice-president of Reserve Mining Company, addressed to Doctor Laleda D. Palekar details the above infor mation and raises serious objection to the conduct of a test using such an atypical fiber. Doctor Cook states that given the chemical, crystolographic and morphological similarity of Reserve Mining Conpeny amphibole fibers to amosite fibers it is most likely that inhal ation exposure to high concentration of these fibers would produce asbestos disease. How ever, it has been ascertained from the various laboratories around the world that the par ticles present in the tailings and in the air in the pelletizer of Reserve Mining Company average less than 3 microns in length and less than 1 micron in diameter. An electron microscope study done by Doctor Peters at Arthur D. Little Laboratories, established thao 9S.t3;i of these fragments were below 5 microns in length. All of the particulates were found to be below 10 microns in length. As stated before, it is the consensus of the scientific community that the short fiber is not fibrotic or carcinogenic in nature and therefore it would appear to me that it is not likely that inhalation of these fibers will produce asbestos disease. Doctor Cook stated that the Harrington and Clark study (2) as showing negative effects in employees in over 20 years experience with Reserve Mining Company. He further states that these studies cannot be extended to conclude that increased rick of lung cancer or meso thelioma is absent. He docs however forget to point that increased risk of lung cancer in asbestos workers occur only in the presence of interstitial fibrosis. These workers, as well cs the individuals who did the x-ray studies detailed above, have found no increase in interstitial fibrosis in Reserve Mining Company employees. Without that finding it is necessary to conclude that there will be no increase risk of lung cancer. Doctor Cook states that the average amphibole fiber concentration in Silver Bay, Minnesota is approximately 125,OCX) fibers per cubic meter for the years 197^> 1975 1976. This corresponds to a fiber concentration of 0.125 fibers per cubic sentimctcr. The present ASARCO ALV 0002665 -5- fiber emission standard for asbestos industry is less than 2 fibers per cubic centimeter over 5 microns long. Therefore the concentrations in the Silver 3ay community are l/lo that of the present asbestos fiber standard. Furthermore, when actual sizing of the fiber is done it will be found that over 98$ of the fibers present in the community air are less than 5 microns in length. Therefore the air eenphibole fiber concentration in the Silver 3a community is probably greater than 2,000 times lover than the present asbestos standard. He does acknowledge that stack emission controls are being installed but expresses a con cern about fugitive dust from the on-land tailings basin vhich will begin operation in IScO Hovever, extensive engineering changes have been made to contain fugitive dust from the tailings basin. Such changes have been approved by the Polution Control Agency of the State of Minnesota. Doctor Cook states that the dose response equation for human inhaled fiber exposure is not veil established and the existence of an exposure threshold, below vhich increased cancer risk is zero, is unknown. Hovever, McDonald et al (15) in his Quebec study cn chrysozile miners indicates that there is an exposure threshold for increased cancer risk. Friedrich: (lo) in 1977 pointed out that the fiber burden in so called normal human lungs is a trem endous quantity. The fiber burden in asbestotic lungs is tvo orders of magnatude greater than that in so called normal human lungs. The correlary to this is that although the fiber burden in so called normal lungs is a tremendous quantity, yet without the presence of as'oestosis excess lung cancers do not develop. These findings are further confirmed in animal studies vhich were conducted by Smith et al (17 & 18) and Stanton 2c Wrench vi0) vhich show progressive reduction in cancer or fibrosis development with reduction i:i Joses of asbestos. J.M.C. Davis (12) in 1977 confirmed these findings using chrysotilc, an.o:\te and chrysotolite. In summary then, Doctor Cook's draft report of June 1, 1973 does not fully tumma-: - . . .'resent state of knowledge concerning taconitc ns an asbestos cr.r.ser hs. :ard. Th.so : great body of evidence regarding the effective fiber length on the induct ion of i; genic cancer. ASARCO ALV 0002666 Respectfully submitted, . />. r^rf/ v. '"< ci-c'-ev ^V_ -X Donald D. Haase, MD Silver Boy Clinic Ltd., Silver Bay, Minnesota 55olb DDH/nj < ASARCO ALV 0002667 BIBLIOGRAPHY 1. Smith, W. E. "Biological Effects of Drinking Water with and without addition of various minerals." Personal report to Reserve Mining Company, 1575 .2 Clark, Terrence C. and Harrington, Vernon A. "Taconite Dust Exposure and Respirat Abnormalities," presented to St. Mary's Hospital Staff, July, 1977- 3 McDonald, J. C., Gibbs, G. W., Liddell, F.D.K., and McDonald, A. D. "Mortality a; long exposure to Cuminingtonite-Grunerite," presented at the American Thoracic Soc Annual Meeting in San Francisco, June 17th, 1977* 4. Bristol, Leonard J. "Personal Communication to the Author." 5 Morgan, Russell H. "Personal Communication to Mr. Maclay R. Hyde." 6. Masson, Thomas J., McKay, Frank W., Miller, Robert V. "aA-s' bestos-Like Fibers in Duluth Water Supply, Relation to Cancer Mortality." JAMA, May 20, 1?7-. 7. Sigurdson, Eunice E., Mandel, Jack., McHugh, Richard., Levy,3arry S., Jarger, Kile Knorr, Robert., Laudon, Zmaline and Pearson, John. "Incidence of Gastrointestinal and Lung Cancer in Residents of Duluth, Two Harbors, Beaver Bay, and Silver Bay 15 1974." presented to the Duluth Medical and Lay Community March 21, 1977* .8 Gillan, J. D., Dement, J. M., Ler.en, R. A., Wagoner, J. K. Archer, 7. E., and H. P. Mortality patterns among hard rock gold miners exposed to an asbestifo mineral. Ann. H.Y. Acad. Sci.. 271, 336-344 (1976). 9 Wright, G. W. and Kuschner, M. "The Influence of Varying Lengths of Glass and Asbestos Fibers on Tissue Response in Guinea Pigs." Unpublished report. .10 Stanton, Mearl F. and WrencSr, Constance. "Mechanisms of Mesothelioma Induction vv Asbestos and Fibrous Glass." Journel national Cancer Institute 4S: 797-321,1572. .11 Morgan, A. "Fibre Dimensions: Their Significance in the Deposition and Clearance Inhaled Fibrous Dusts." presented at the Society for Occupational and Environment? Health, Washington, D. C. 1977* .12 Davis, J.M.G. "Current Concepts in Asbestos Fibre Pathogenicity." presente Society for Occupational and Environmental Health, Washington, D. C. 1977. 13. Bignon, J., Sebastien, P., Gaudicher, A., and Bonnaud, G. Measurement of asbestos retention in humans related to health effects. U. S. Bureau of Standards M.:.e*ing 0 Asgestos, Gaithersburg, Maryland (1977) 14. Banovetz Letter to Doctor Palekar See enclosed copy. 15. .McDonald, J. Corbett, McDonald, Alison D., Gibbs, Graham W., Sicmiatycki, J Roooitcr, Charles E. "Mortality in the Chrycotile Asbestos Mines and Mills Quebec." Archives of Environmental Health, Volume 22, June 1971. t 15. Friedrichs, K. H. "Morphological Aspects of 'various Fiber Collective ct the Soci ety of Occupational and Environmental .Health Symposium, Wn so 1977. ASARCO ALV 0002668 -217. Smith, Wn. E., Hubert, D. D., Miller, L., Badollet, M.S., and Chur3, J. "Test s 1. . Threshold Levels of Carcinogenicity of Asbestos." Internationale Konfcrenz ue ser die biologischen Wirlcungen des Asbestes. Dresden 1963, Pp 317IS. Smith, William E. "Experimental Studies on Biological Effects of Tremolite Ta1c on Hamster." Presented at the Symposium on Talc Dust Hazards, U. S. Bureau of Mi ne s, Washington, D. C. May 8, 1973* * ASARCO ALV 0002669