Document E3BGVRV2OKmjwvv8B2G7vz0

A. E. ALPINE SENIOR EXECUTIVE VICE PRESIDENTGENERAL MANAGER CEMENT ASBESTOS PRODUCTS CO. January 11, 1977 TO: Bruce Klomfas Circulate to Gerald Fox v C------- :----------------- ) A. E. Alpine CAPCO JEN 0002331 6 January 1977 Memorandum For: MEMBERS Subject: Statement in Response to Inquiries with Regard to NI03H Report to 05HA on Health Effects of Occupational Exposure to Asbestos. The attached statement, prepared following initial analysis and comment by the members of the Executive Committee,the Association's medical advisor and others, is forwarded for information and appropriate use. The statement is being used in response to queries addressed to the Association. Effect of the NTOSH document, forwarded to members by memorandum dated December 21, is not known at this time and will probably not be known until after the change of Administration. Current news stories reqardinq problems with asbestos in ceiling materials and continuing inquiries into the asbestos-health issue both in the United States and abroad may hasten public hearinq on the proposed re vision to theOSHA standard for exposure to asbestos dust in the workplace. . A letter to Dr. Corn, Assistant Secretary of Labor (OSHA), with regard to the NIOSH document, is being prepared. Executive Director RHM-.v Enclosure CAPCO JEN 0002332 ASBESTOS INFORMATION ASSOCIATION WORTH AMCHtCA 1635 K Street, N.W., Washington, D.C. 20006 (202) 223-4885 6 January 1977 Statement Regarding NJOSII Document: to OSHA Dated December 1976 "Re-examination and Up-date of Information on the Health Effects of Occuoational Exocsure to Asbestos" == t From preliminary review of the NIOSH document, "Re examination and Update of Information on the Health Effects of Occupational Exposure to Asbestos," dated December 1976 and transmitted to the Department of Labor December 15, the follow ing comments are made: . Studies cited in the NIOSH document do not define the levels of airborne asbestos dust to which individuals were exposed. The level's of exposure were most probably much higher than those now being experienced in the workplace. There is no evidence to support the proposition that the present OSHA standard for occupational exposure to asbestos-- viz 2 f/cc of air longer than 5 microns in an eight-hour time-weighted average with a ceiling limitation against any exposure in excels of 10 f/cc is not safe for exposed popu lations. . Contrary to the NIOSH statement, state of the art and practical considerations rule out sampling and analytical n.Aor.n .JEN 0002333 rated by the presence of a chrysotile fiber in the digest of GI tissue of a rat given taconite tailings, and the pres ence of a fiber consistent with either amosite or taconite tailings in the di gest of mesenteric tissue of a control rat), it is noteworthy that following the administration of a single large dose (400 mg) of either amosite or taconite, no evidence of trans migration of fibers was observed in 16 of the IS rats gsvaged. ,,,e Oleomargarine Feeding The results of this portion of the in vestigation indicate that if trans migration of mineral fibers from the GI tract occurs at all, it must be a rare event since only five fibers con sistent with those ingested were found in the digests of mesentery of three rats and four such fibers were found in the lung digests of two other rats (Table 1). Other fibers (five in all) found in the digests of mesenteric tissue of three rats probably repre sented contaminations-sucli as the chrysotile fiber in the digest of the rat fed amosite. The importance of the nine fibers (Table 1) found in the tissue digests of five of the 37 rats fed or gavaged with mineral fibers must be evaluated in the perspective of the billions on billions of fibers that had been in troduced into the GI tract of these animals. If transmigration of fibers through the GI wall were a fact, one would logically expect more than one to three fibers out of many billions to accomplish this feat, and this phe nomenon should be demonstrable in more than five out of 37 rats. The dose of asbestos ingested by the rats is equivalent to a consumption of 1.1 to 2.5 kg asbestos by a 75-kg man in six days, and double this amount in terms of taconite tailings. The impor tance of the nine fibers found is re duced to a negligible level by the finding in four rats of five fibers that are obvious contaminants, thus point ing to a very high probability that the nine fibers in question are also con taminants. As indicated previously, all fibers were ultramicroscopic in di mensions, and could have been de rived from the air of the laboratory, as well as from the unfdtered water and the technique used (weighing, of the tissues) in the preparation of the study samples. Butter Feeding Tiie failure to detect penetration of the GI mucosa or transmigration of optically visible fibers in this study is important since asbestos fibers in this size range are known to be patho genic, and there is a growing body of evidence to indicate that asbestos fi bers in the submicronic size range are not pathogenic.* The fact that no can cer of the GI tract or mesothelium de veloped after long-term exposure of the GI mucosa to large numbers of as bestos fibers is highly significant Long-Term ad Libitum Feeding of Asbestos in Butter The lack of success in the third lab oratory using optical as well as elec tron microscopy in finding evidence of penetration of asbestos fibers after one and three months of ingestion of these mineral fibers respectively, adds weight to the importance of these negative findings in the other two laboratories. GENERAL COMMENTS The method of digestion used in this investigation by one laboratory is faulted by the possibility of chance contamination that may he difficult to evaluate and thereby give rise to false-positive results. The possibility of false-negative results also exists. For instance, fibers may be lost by in complete digestion of the tissue, by incomplete sedimentation during cen trifugation, and by being covered with partially digested material on the electron microscope grid. How ever, in view of the ratio of the amount of tissue examined by the di gestion method as compared with that examined by the electron micro scope section method (many thou sands to one), the chance of a nega tive result with the former when the latter is positive would appear to be negligible. Although transmigration of large objects such as bullets from one por tion of the body to another has been documented, this transmigration is concerned with foreign materials that had already achieved penetra tion into the body interstitium. The penetratiou of inhaled dust particles through the alveolar membrane and the subsequent lymphatic transport to satellite nodes has been recognized and studied experimentally for more than a century but the mechanism by which this penetration takes place is still unknown. Drinker and Field'* did determine that particles may pene trate the alveolar membrane and ap pear in the lymphatic fluid within minutes after their insulation into the lung of a dog. This rapid pene tration of the alveolar membrane by Table 1.--Tabulation of Fibers Found in Oigests of Tissues* Fibers Found Contaminating Fibers (Chrysotile and Others) Tissue Digest Mesentery Lung or kidney Total Dust Amosite 7 rats Taconito tailings 10 rats Control (no dust) 4 rats Amosite 10 rats Taconite tailings 10 rats Control (no dust) 7 rats 43 rats No. Week.Raft * No. 2 2 wk 2 5 wk 1 wk (chrysotile) 1 1 wit 2wk (chrysotile) GI tract 2 1 2 wk (lung) 3 2/7 wk savage (lung) (kidney) 9S * Electron microscopic examination, t Week-rat refers to the animal killed at specified time. Arch Environ Heallh/Vof 29. Oec 1974 Ingested Mineral Fibers/Gross et al 345 CAPCO JEN 0002334. Type* of Tumor Mesothelioma Carcinoma Sarcoma Lymphoma No. of animals Table 2.--Tabulation of Tumors Found in Rats Fed Asbestos 'Chrysotile, 10 mg 0 2 (breast) 0 0 31 Expvrir Crocidolite, Smg 0 0 0 0 33 Crocidolite, 10 mg 0 0 0 1 (axillary nodes) 34 Control 0 3 (breast) 1 (thigh) 1 - 24 NWCipe Crocidolite, 10 mg 0 0 0 Q 35 Experiment 3 Crocidolite, 10 mg 0 0 0 0 26 Control 0 0 0 0 24 particles was confirmed by Ham burger and Robertson" using a dif ferent technique. There are, however, important dif ferences between the alveolar mem brane that protects the lung interstitium from intrusion by foreign material and the GI mucosa that, among other functions, also performs a similar guard duty. Whereas the al veolar membrane is largely composed of thin squamous cells, the intestinal mucosa is composed not only of mu cin-covered tall columnar epithelium but also by a substantial tunica propria mucosae. The GI mucosa con stitutes. therefore, a barrier against the intrusion of foreign materials that is many times more formidable than the alveolar membrane. Penetration of the alveolar mem brane, as an accomplished fact, is best demonstrated by the presence of en larged, discolored, and often stonyhard satellite lymph nodes. No such involvement of mesenteric lymph nodes has been described in coal min ers or silicotic hard-rock miners even though they had ingested during their lifetime many times the amount of dust than finally remained stored in their lungs and satellite nodes. Consideration should be given to the fact that the dust stored in the lungs is estimated to represent only 1% to 2Tc of the dust that had been inhaled and, after clearance from the lungs, swallowed. If penetration of finely divided for eign particles through the GI mucosa Rare a common event or even a rela tively unrommon event, over the life time of an individual, the suhmucosa of the GI tract and the mesenteric lymph nodes would be the repositories for a considerable accumulation of a wide variety of materials other than those cleared from the lungs. One need only consider the wide variety of insoluble materials, mostly cellulosic, that are part of many foods. Some, like pepper, can be very irritating when in contact with unprotected tis sue and would cause a severe in flammatory reaction. Furthermore, if penetration of the GI mucosa by par ticulates did occur, the amount of stored material in the intestinal sub mucosa and in mesenteric lymph nodes would increase with age. The fact, however, is that storage of such foreign material has not been seen in either the intestinal wall or the mes enteric nodes. The failure to find fibers by elec tron microscopic examination in sec tions of intestinal wall of rats fed asbestos or taconite tailings is con sonant with the failure to find evi dence of transmigration in the di gests of ocher tissues of these animals. SUMMARY The more important conclusions can be briefly summarized as follows: 1. Twenty-one months of intimate contact of rat GI mucosa with very high concentrations of chrysotile as bestos failed to produce cancer or any other kind of lesion. These results are highly important inasmuch as in ear lier work different modes of asbestos exposure have resulted in cancer pro duction within 16 to 17 months. 2. Twenty-one months of high-dosage-chrysotile feeding of rats re sulted in no evidence of penetration of GI mucosa by the mineral fibers and no incontrovertible proof of transmigration as judged from elec tron microscopic studies. 3. Administration of a single dose of 400 mg of either amosite or taco nite tailings by gavage provided no evidence of transmigration of fibers even though the method of examina tion used was many thousand times more sensitive than the method of ex amining tissue sections. 4. The voluntary intake by rats within six days of 2 to 10 gm of amo site or taconite tailings mixed in oleo margarine likewise provided no evi dence of transmigration of mineral fibers, although a total of nine fibers was found in all of five rats that could have been considered evidence for transmigration, except for the proba bility that they were contaminants. 5. Short-term and long-term feed ing (up to l'A years) of chrysotile and crocidolite by a second laboratory re sulted in no tumor production in the GI tract or mesothelium during the lifetime of the animals. Light micro scopic studies provided no evidence that penetration of tissues by in gested asbestos fibers occurred. 6. A partially completed light mi croscopic and electron microscopic study in a third laboratory has pro vided data that support the results and conclusions of the other two labo ratories with regard to the failure of ingested asbestos fibers to penetrate tissues. 7. The penetration of the pulmo nary alveolar membrane and trans migration of inhaled dust particles are facts readily demonstrable by the presence of enlarged, discolored, min eralized tracheobronchial lymph nodes. In contrast to this, the GI mu cosa, constituting a much more formi- 34S Arch Environ Health/Vol 29. Dec 1974 Ingested Mineral Fibers/Gross et at CAPCO JEN 0002335 dablc barrier, does not permit the penetration of insoluble particulates as is evidenced by the lack of similar involvement of mesenteric lymph nodes in miners who, during their lifetimes, ingest nearly 100 times the amount of dust stored in their lungs and satellite lymph nodes, plus the considerable amount of insoluble par* ticulates in the daily food intake. Nei- ther is evidence of penetration or storage of inhaled or ingested foreign material to be found in the intestinal wall of these miners. 1. Gross P, ct at: Mineral fiber content of hu man lungs A comparison of the counts obtained from the lungs of people of Pittsburgh, Fennayl* vania, with those from the lungs of people of Charleston, South Carolina. Am lud IIyg Atme J, to be published. 2. Langer AM: Discussion in Langer AM, etal: Inorganic fibers, including chrysolite, in lungs of autopsy: Preliminary report, in Walton WH (ed): Inhaled Particle*: III. Unwin Brothers, Limited, The Gresham Press, Old Woking, Sumy, En gland, 1371, vol 2, p G93. 3. Polieard A, quoted by Gordonoff T: Epurv* tion pufmooaire, in Ccmtpf* fienrfut det Jvumtet Franqaitet de Pathologic Milter*. Paris, Cbarbo- References nage de France, Oct 27-28,1960, p 165. 4. Bonser GM, Clayson DB: Feeding of blue asbestos to rats, in the 45th Annual Reports of ffie British Empire Cancer Campaign. 1967, p 242. 5. Smith WR Asbestos, talc end nitrites in re lation to gastric cancer. Am Ind Hyg Attoe J 34:227-228,1973. 6. Gross P, el ah Experimental asoestosis: The development of lung canear in ruts with pulmo nary deposits of chrysolite asbestos dust Arch Environ Health 15JW3-355,1967. 7. Gross P, Harley RA Jr Asbestos-induced intratboraeie tissue reactions. Arch Pathol 964fr>250,1973. 8. Pontefract RD, Cunningham HM: Peae* tration of a&bcstos through the digestive tract of rata. S'ature 243 352-353,1973L 9. Ones P: Is short-fibered asbestos oust a bio logical hazard? Arch Environ Health 25:115-117, 1974. 10. Drinker CK, Field JIE: Lymphatic*. Lymph and Titnue Fluid. Baltimore, WHUarasA WiRcins Co. 1933. 11. HamburgerM. Robertson OH. unpublished experiments quoted by Rooeruoo OH: Phagocy tosis of foreign material in the lung. Phyeid Ret 21:112,1941. MYTHOLOGY / Index of Gods, Etc The Triple Gods The triple gods of hypertension And other osclerosis-- Sir William Osier is Authority for this recension-- The triple gods, I meant to say. Were Bachus, Vulcan, Venus. Sir William's counsel is hygienous And surely non-sclerotic, though it may Be justa nute restrictive; 1 remark The lethal one of these is work. Charon I sing of Charon and his ferry-- The price is right. Short is the flight. But the journey is dismal--very. --Rusticatus Arch Environ Health/Vol 29. Dec 1974 Ingested Mineral Fiber? CAPCO JEN 0002336 Page 2 functions at a 0.1 f/cc level --the standard level recom mended by NIOSII to OSHA -- by phase contrast microscopy at -400 - 450x magnification. Asbestos is a generic ! term used for several fibrous minerals found in many areas of the earth's crust. Chrysotile, a serpentine mineral fiber, is the most common form of as bestos. Because of extraordinary fire and heat resistance, strength and stability and other unusual physical properties along with availability at relatively low cost, asbestos is used in a wide variety of domestic products and industrial applications, in many cases without practicable substitute. In most products wherein asbestos is a vital ingredient, the fibers are bonded \or locked in as with asbestos cement, plastics, millboard and hundreds of other products. The risk of exposure to respirable particles of asbestos from normal use of these products is negligible. Spraying of asbestos for insulating purposes, once a fairly common practice, is prohibited by federal regulation. The absence of proper dust control procedures particularly in the World War II period and before when little was known as to the effect of excessive exposures of asbestos dust on worker's health led to the incidence of asbestos-^related disease following now known latency periods. With the knowledge of risks to health from asbestos dust that-the medical community began to recognize in the 1930s and 1940s, the asbestos industy -- mining, milling and product manufacture -- has spent millions CAPCO JEN 0002337 Page 3 of dollars on medical research and engineering systems for dust control. The asbestos industry continues its extensive efforts to eliminate worker exposure to asbestos dust through engineering controls and disciplined work practices. Concurrently, the tempo of investigation into the many questions surrounding the highly publicized asbestoshealth relationship -- including research and analysis of evidence of asbestosis, lung and GI cancer and the rare disease mesothelioma -- has accelerated in world-wide effort to develop thorough scientific information on which to base sound, unemotional judgment on the issues of asbestos and health. Conformance with the present OSKA regulatory standard, a challenging job, is being accomplished. Comments on the proposed revision to the OSHA standard for occupational exposure to asbestos, from 2 f/cc to 0.5f/cc (29CFR Part 1910), submitted by this Association on behalf of the asbestos industry April 9, 1976 are available for review. The asbestos industry, after in-depth study of medical literature, technical feasibility and economic impact by independent consultants has recommended to OSHA adoption of a permanent standard of 2 f/cc of air time-weighted average, with a peak of 10 f/cc, using the membrane filter test method, phase contrast microscopy at 400-450 x magnification. CAPCO JEN 0002338 Page 4 In its written comment to OSHA on behalf of the 1 asbestos industry the Asbestos Information Association/ North America stated: " Since there is no new evidence to indicate that the 2 f/cc TWA standard adopted in 1972 does not adequately pro tect the health of the working population, it would be grossly inequitable and a denial of due process to lower the standard at this time." This statement continues to reflect the studied opinion of the asbestos industry. R. H. Mereness, Executive Director, AIA/NA CAPCO JEN 0002339