Document 3JvRML2MVQ0EReOa0wJxxDQ0x

MINNEAPOLIS DIVISION OF PUBLIC HEALTH PUBLIC HEALTH CENTER - 250 SOUTH FOURTH ST. KARL R. LUNDBBtG, M.O. WRG 001936 March 9, 1961 Occupational Health field Headquarter* U. S. Public Health Service lOlIi Broadway Cincinnati 2, Ohio Dear Sir*i m.ATTENTION i DOHRKAN H. BIERS --. I an writing you at this tine for further Information on rerad.cullt*. I her* on my files a letter dated May the 27th, 1955, vhioh was addressed to me and signed by Melvin M. Udel, Assistant Surgeon, Clinical Services. This sea in reply to my letter inquiring about the clinical effedts of ranaleullte. At that time we had a ease of pneumoconiosis ehloh was thought to be related to a hoary exposure to reneiculite dust. We hare recently had another oase of siadlar pneumoooniosis reported to us. This workman has also been exposed to D reraieullte dust of a long period of time. The reraioulitB is being produced for us* as insulation. Although the workmen involved are in two separate companies, they use the asms source of raw product idileh is the sooolite brand. I wonder if you oan supply ms with more recent information in regard to tbs effects of veraioulit* dust, and was outlined in Dr. Udel's letter of May the 27th, 1955. Through his letter and further artlales which I have at hand I have the following referenoes relating to this subject. 1) Dreeseen, W. C.j Dalle Tails* J. M.j Edwards, T. I.j Sayers, R. R.j Eason, H. F.j and Trios, M. 7.j "Pneumoconiosis Among Kioa and Pegmatite Workers", Public Health Bulletin, Re. 250, D.S.P.H.S. 19i0. 2) Vestal, T. 7.) Winstead, J. A.j and Joliet, Paul V.j "Pneumoooniosis Among Mica and Pegmatite Workers", Industrial Medicine, Vol. 12, No. 1, page 11, January 19U3* 3) Harihara, C. R.j Oupta, M. M.j and Moniker, I. S.j "Notes on Mica Dust Inhalation", A. M. A. Archives of Industrial Hygiene and Occupational Medicine, Vol. 8, Vo. 6, December l953 peg" 531. " U) Parade, A.] "Silicatosis Caused by Sepiolite", Mad. Sogur. Trab., 2t ll-lli. January - March 195U, (abstracted in IndustrialHygiene Digest, Vol. 19, No. li, page 30, April 1955.) 5) Patty, Vol. 1 (Second Revised Edition) 1956, peg* 361, item 3 bottom of page. 6) Vorwald, Arthur J.j "Diffuse Fibrogenic Pneumoconiosis", Industrial Med. ^ Surg., Vol. 29* August I960, pp. 353 ~ 35& Vie are proceeding to raake a such more detailed Investigation of both of these cases of oneuntoconiosis and hope to have additional information which we will be glad to share with you. Very truly yours. W. E. Park, K 0,, Chief Occupational Health service VffiP/gjk DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Dr. W. E. Park, Chief Occupational Health Service Division of Public Health 250 South Fourth Street Minneapolis, Minnesota Dear Dr. Park: Your letter of March 9, 1961, a request for recent literature on the biologic effects of vemdculite, has been referred to me for reply. I am sorry to say that new information on this subject published during the past five years is quite limited. A need for further study of the relationships between the silicates and pulmonary disease certainly exists. Enclosed are three abstracts copied^ from the Industrial Hygiene Digest that were not included in your list of references. Another article that is old but relative to the subject is also mentioned. Johnstone and Miller in their new book "Occupational Diseases and Industrial Medicine," W. B. Saunders Company, Philadelphia, I960, classify various pulmonary responses to industrial dusts. Mica is broken down in this manner: Mica Physical Characteristics Chemical Formula Tissue Response Possible Entity Muscovite Crystalline (sericite) K2O.3AI2O3 6Si022H20 Foreign Body Minor silicate Reaction pneumoconiosis Biotite Crystalline Venniculi.te Plates H2K(Mg, Fe)^ Foreign Body 3Al(SiO]4)3 Reaction Varied hydrated Foreign Body silicates Reaction Minor silicate pneumoconiosis Minor silicate pneumoconiosis Under their section on Minor Pneumoconioses they discuss the usual pulmonary response to these silicates as consisting of an elaboration of a fine reticulum of fibers forming a loose mesh.throughout the packed masses of dust cells. These changes are apparently responsible for an accentuation of linear markings and reticulation that is evident on a chest x-ray examination. Dr. W. E. Park, Chief -- 24arch 27, 1961 IJe are very much interested in the results of your pending investi gation of the two men exposed to vermiculite dust. Please do not hesitate to write us again if we can be of further help to you. Sincere1y yours. Edyj L. Gibson, O'Coupaticnal 00 e Section -3- 1. Polican, A.: The action of mica dust on pulmonary tissue. J. Ind. Hyg. 16:160, 193U. 2. Ramaswany, A. S., Venkatish, D. S., and Rama Rao, R.: The nature of lesions caused by asbestos and mica in experimental pneumoconiosis in guinea oigs. J. Indian Inst. Sc. 35, Sect. A., 319, Oct., 1953. (Ind. Hyg. Dig. *18. No. 550, 195k). Guinea pigs were subjected to intratracheal injections of mica and asbestos dusts. Stress is laid on the development, after long periods, of lesions in other organs besides the lungs, especially in the adrenal glands. Mica dust was found to lead to some degree of nodular formation in the lungs, but the asbestos dust set up diffuse fibrosis only. These differences are portrayed in a series of photomicrographs. Mica induced hypertrophy of the adrenal cortex with extensive foairy disintegration of the cortical cells; asbestos induced lesser changes, but small areas of necrosis were occasionally found in the zona fasciculata and zona reticulata. In a theoretical dis cussion the authors attempt to draw a relation between the atomic structure of mica and asbestos and the pathological lesions in the lungs and other organs. Their theory, however, leaves many points unexplained. - Cond. from Bull. I$rg. 3. Gupta, M. N.: Silicosis amongst supervisory staff in mica mining in Bihar. Report No. 8 Govern, of India, Ministry of Labor, Office of the Chief Advisor Factories, New Delhi, India. 6pp,.1955. Ind. Hyg. Digest 21: No. 1U37, 1957. The silicosis hazard among the supervisory staff in mica mining was studied. Nodular and conglomerate silicosis was found in hS-2% of the supervisory staff and was fairly well correlated to the number of years spent in underground work. Pulmonary tuberculosis was found in 19^ of the supervisory staff. li. Health Hazards in Mica Processing, India, Government of: Ministry of Labour. Report No. U. Office of the Chief Advisor Factories, Ministry of Labour and Employment. New Delhi, llpp, 195k. (Ind. flyg. Dig. 23: No. 186, 1959). The production of mica in India increased frcra 6,000 tons in 1939 to nearly 10,000 tons .in 1951 and the industry now employs about 27,000 workers, 16,500 of whom work underground. A recent investigation revealed a high prevalence of silicosis in mica miners. The hazard in mica mining is mainly from free silica and the investigation described in this report was carried out to determine the importance of inhalation of mica dust. Dust measurements taken during the different processing operations were found to exceed the maximum allowable concentration (MAC) for mica of 20 million particles per cubic foot in screening and grinding mica. Chest x-rays of 61 workers, 53 men and eight women were taken; 5 of those studied worked in processing factories and three in mica grinding. Twenty (32.7%) of the x-rays were recorded as showing "linear exaggeration" and Ul (67.3;?) "ground glass" appearances. No x-rays showed nodular silicosis and none were recorded as normal. The self-evident conclusion is drawn that it is desirable to keep "the dust concentration of mica within safe limits". As no nodular case was noted in the 61 vrorkers whose average time intensity factor was 360, equivalent to 18 years exposure to 20 million particles per cubic foot, the suggested MAC is considered reasonable.- Cond. from Bull. Hyg. r