Document 0Jd37651Rr5ZozNQrLaVZzjJO

THE DISCOVERY COMPANY UNION CARBIDE CORPORATION MINING & METALS DIVISION P.O. BOX S79 NIAGARA FALLS, N. Y. 14302 TEL: 716-278 3376 December 2, 1975 Mr. D. Varacallo, Jr. Journal of Coatings Technology 1315 Walnut Street Suite 830 Philadelphia, PA 19107 Dear Mr. Varacallo: Enclosed is the proof which you sent to me for conments, which are marked in red. Very truly yours, Marketing Manager JLM:dal Enclosure t \ r s r* /-*i O U JO1, Mon., bee been M M M . b..i on ofwou. it Author's Proofs Handling Asbestos Handling Asbestos Chrysotile Asbestos in Plastics John L. Myers Union Carbide Corporation* Asbestos has received a great deal of attention and publicity in recent years, especially after it was designated a "target health hazard" by OSMA and a "hazardous air pollutant" by the EPA. Many of the articles on asbestos by the press have been emotionally oriented or distorted and, in some cases. \Stories have been sensationalized, based on obvious misinformation of facts. ; The use of half-truths or unsubstantiated statements has-led to general con fusion and the unfair castigation of asbestos and products containing asbestos. The purpose of this paper is to put the matter of asbestos use and asbestos hazards into a logical and practical perspective. In this paper, the different types of asbestos and their many uses are discussed, along with government regulations controlling the use of asbestos. The health hazards associated with asbestos, both occupational and environmental, and some industrial experience with air sampling and dust control measures are also covered. ; , i ,acB / i C ^ ~> H U' U U U / "3 JOHN L. MYERS. Marketing Manager tor tne Calidria Asbestos Group in Union Carbide's Mining- rnj Metals Div., received his Cj.S. Degree in Chemical Engineering from Purdue University in 1951. Joining Union Carbide that same year, tie served in the diihioiun end th<-cnotieet-~'op`.. rations until lCfc6. when he became a Research Engineer in the asbestos group. He was promoted to his present position in 1S70. t i i f.' O ^ OoU< e 385 JPT (Dec) .... Gal 1 0 'fl'Cj/ V' dtJL*jJ I'e'UuJLjl <r/ji/7y 01 Amm '/6jI aNJua.Vn*rFne.mMarHrnMmni3i,iIcSUdIrS.m7amSint. aitrhtbMcCel*ttlaiUlaslirtnSHaCin*.u. IrraNSiioMa*aijriaiturva.'t (Mjlialn... Falb. I > *y What is Asbestos? __ S<3a- pT<M*^rVo Asbestos is a commercial or generic term used to describe six naturally occurring "asbostifumi" minerals tliat are fibrous, hydrated metal silicates. The six varieties are divided into two classes--serpentine and amphibole-- based on their crystal structure. Clirysotile is the only member of the serpentine class, wliilc die amphiboles include crocidolite, amosite, anthophyllite, tremolite, and actinolite. Chrysotilc is by far the most-used variety and accounts for over 952 of U.S. consumption, as noted in Table 1. Crocidolite, also known as blue as bestos, is imported from South Africa. Because of its high mechanical strength and good resistance to acids and alkalis, it is used to reinforce a limited variety of plastics where its pronounced color is not objectionable. Amosite,- also imported from South Africa, is used primarily in thermal insulation. Although there are some deposits of anthopliyllite in the U.S., most of it is imported from Finland. It ps) used primarily as a filler for polypropylene and in insulating ma terials. A comparison of the four varieties of asbestos which are of com mercial importance is presented in Table 2. It should be noted that there are significant differences between f~A< chrysctile and'amphiboles with reg.TnF to chemical composition and certain physical properties. Where is Asbestos Used and Why? Asbestos has served mankind for more than 100 years in a broad vari ety of applications. The general areas in which asbestos is used in the U.S. are shown in Table 3. based on infor mation from as'liestos producers and consumption surveys, it is estimated that the plastics industry uses about 332 of the S00,l)00 tons consumed an nually, which makes it (ho largest single user of asbestos fiber. The largest uses of asbestos bv the plastics industry are in vinyl-aslwstos floor tile and in phenolic molding compounds. It is also used in other plastics such as polypropylene. pnl\ester, nylon, melamine. cpo\y. sili cone, and vinyl. Asbestos provides a valuable function in sneb products as brake linings, clutch facings, electrical components, automotive parts. Iiimiture, boats, sealants, coatings, adhe sives and mastics. The most important functions of asbestos in plasties are re inforcement. dimensional stahilitv. fietSC icey -- /4-S t&rVTO z> hiSALTH Plastic^ pOLtuTloAf "XcK^ccco 6y SA F^Ty tA& <3.ia4/tc 'jilly Hi1/#7<o , o p J Ia U O O erai-putpoae ailing. Most ot the tunc* lions arc supplied by sltor;-fil>cr cltrysotile ast>cstos filler, although longer chrysotile fibers and other as bestos varieties are sometimes re quired for particular properties. Why Use Chrysotile?. Among flic several advantages of chrysotile. which set it apart from the amphibole minerals and account for its widespread and increasing us age. are world-wide availability, me chanical strength, flexibility, positive surface charge, low iron content, soft ness, and low refractive index. It is conservatively estimated that chryso tile asbestos is used in over 3,000 ap plications and, in most of these appli cations, it is an essential ingredient for which no replacement is readily available. The information in Tabic 1 shows that the use of chrysotile asbestos and its share of the total market are stead ily increasing. This is due partly to technical advances permitting the broader use of chrysotile in plastics and the general decline in the use of asbestos in certain fireproofing and in sulating materials. In addition, there is increasing evidence that crocidolite and amosite are more hazardous to human health than chrysotile.1 Since 1970, the use of crocidolite in britain has been restricted after a panel of experts "concluded there was suffi cient evidence to suggest other types of fibre should be substituted for crocidolite wherever possible."* f What is the Asbestos Hazard? It is readily accepted that asbestos, like many other foreign liodics, can cause disabling lung damage (pul monary fibrosis), commonly referred to as asbestosis. This disease and bronchogenic carcinoma (lung can cer) are the two most common as bestos-related diseases. It is important to note that, based on epidemiological data, these diseases have occurred primarily in workers with high, long term exposures to asbestos dust. It is cf further interest that one noted re searcher has reported that neither of these diseases is peculiarly related to or caused solely by the inhalation of asliestos filler.' Another important con sideration is the, relation between cigarette smoking and lung cancer, as reported by Dr. E. C. Hammond and Dr. I. J. Sclikofl.* In this study, they reported tltat: "It seems elear, then, that lung cancer is uncommon among aslK'stos insulation workers who have no histcry of cigarette smoking and that if the risk is increased, such in crease is not great." 585 TPJ (t>cc) Cal 2 A third disease, mesothelioma, has more recently hcen associated with persons exposed to asbestos. Meso thelioma is an extremely rare cancer of the lining of the chest (pleura) or the abdominal cavity (peritoneum). In contrast to the lung diseases, there is some evidence that mesothelioma ran occur after brief exposures to relatively high fiber levels. According to the 33-memlicr Ad visory Committee on Asliestos Can cers of the International Agency for Kesearch on Cancer (a division of the World Health Organization): "There is evidence of an association of meso- Ihclial tumors with air pollution in the neighliorhood of crocidolite mines and of factories using mixtures of as bestos filler types. The evidence re lates to c inditions of many years ago. There is evidence of no excess risk of mesotheliomas from asbestos air pollution which has existed--in--the--- O neighliorhood of chrysftile and amo- site mines. There are reported differ ences c n incidence of mesothelioma between urban and rural areas, the causes of which have not been estab lished. There is no evidence of a risk to the general public at present"* The same body quoted aliove has also concluded that there is, at pres ent, no evidence of lung damage by asliestos to the general public; anil such evidence as there is docs not in dicate any risk of cancer resulting from asbestos fibers present in water, beverages, food, or in the iftrds used for the administration of dnf * While there seems to he general agreement that the public is not in any present danger from asliestos, it is also reccgnized that excessive, long term occupational exposure can cause serious health problems. Also, if man made emissions are not controlled, then environmental contamination could approach harmful levels. During the past two years, significant legislation has been enacted by the Federal government to reduce and control occupational exposure to as bestos fillers and to minimize filler emissions to the environment. Addi tional standards or regulations have hcen proposed or enacted by many states and local governments. Summary of OSHA Regulations The William-Steiger Occupational Safely and Health Act of 1970 beTlmic effective on April 28, 1971, with the fullc.wing Congressional purpose: "To assure so far as possible every working man anil woman in the na tion safe and healthful ivqrk.'Dg con ditions and to preserve our humalniT- resources." The Act established the C* 0OW fU? Occupational .'lately and Health Ail- ministration (OSIIA) within the De partment of Lain*, which has re sponsibility for administration and enforcement. Research and related functions arc handled by the Depart ment of Health. Education and Wel fare (1IEW) through the National Institute of Occupational Safely and Health (NIOSH). Five million em ployers and 60 million of the nation s 80 million workers arc covered by OSHA. Specifically excluded from coverage are government employees and operations which arc protected under other federal health and safety laws. In a news release issued January 4. 1972, OSHA announced a Target Health Hazards Program aimed at improving health factors associated with working conditions. The follow ing five substances were designated to be the focus of initial and con certed efforts by OSIIA and NIOSH: asbestos, cotton dust, silica, lead, and carbon monoxide. At the present time, new standards have been established only for asbes- toj/ although, of the 8,000 toxic sub- "sfances cn the NIOSH list, only 500 are covered by standards and many of those need updating. The new Standard for Exposure to Asbestos Dust was published in the Federal Rciitetcr, Vol. 37, No. 110, on June 7, 1972. The basic exposure standard is an 8-hr time weighted average (TWA) of five fibers, longer than 5 micrometers, per cubic centimeter of air. The TWA limit is to lie reduced to two fillers per cubic centimeter on July 1, 1976. A peak concentration of 10 fibers per cubic centimeter is not to be exceeded at any time. All of the fiber concentrations are those to which an employee may be ex posed without protective clothing and equipment. The first basic require ment of the new standard is monitor ing to determine whether or not fiber concentrations are in excess of the exposure limits. Some asbestos sup pliers provide a monitoring service to customers, and a similar service may he obtained from state health depart ment officials, insurance carriers, or private consultants. The law requires that monitoring be repeated as nec essary to ensure that employees arc not exposed to levels in excess cf the exposure limits. , J8D JFT (IVc) ----------------------- Cal S Improper interpretation of the reg ulations has created many miscon ceptions about equipment and pro cedures needed to properly use asbestos, if exposure limits are not exceeded, there are no further com pliance requirements except for med ical examinations. Medical examina tions are required for all employees in any occupation exposed to airborne concentrations of asbestos fillers. The examinations are relatively simple and should cost no more than $50 per year, per employee. Respirators and special clothing are required in the construction trade fer the spray application of insulation and fireproofing materials, and for the removal of such materials. This spe cial protection is not required for any other use of asbestos unless exposure I'mils are exceeded. This is also true for ether items such as specially equipped tools, change rooms, clothes laundering, and waste disposal. Res pirators arc not a substitute for en gineering controls, but the law allows their use while controls arc being implemented, in special situations where controls are not feasible or adequate, in emergencies, and for in frequent short-term job assignments. Caution labels are required on prod ucts containing asbestos except where the fibers have been modified by a bonding agent or ether material to prevent dusting during any normal subsequent use or handling, besides raw asbestos fiber, products which require package labeling could in clude: dry acoustical spray products and joint cements, unsaturated roof ing felt and textiles, and some in sulating products made without ade quate binders. The labeling cf a prod uct does not prohibit its use. It should be noted here that in at least 902 of the products containing as bestos, the fibers are solidly locked into the product thereby presenting little danger of dust generation dur ing normal use and handling of the product.* EPA Standards Whereas OSHA is responsible for the protection of the worker, the Envimnmcntal Protection Agency (EPA) is charged with improving the en vironment to which the general public is exposed. On March 31. 1971, as bestos, along with beryllium ami mercury", was identified as a "hazard ous a:r pollutant" by the Administra tor of the EPA. National Emission Standards for asbestos were then ptil>lished by EPA in the Federal Regis ter, Vol. 38, No. 6G, April G, 1973. Although no numerical emission stan dards were established, operating cri teria arc prescribed to prevent or limit asbestos emissions to the nnl- f s o C\ o A ^U OJ J dards were established, operating cri teria are prescril>vd to prevent or limit aslwstos emissions to the nnt-- <1* sidc air from asbestos(fniE^ roadways, certain manufacturing operations, building demolition, and the sprav-on application of materials used to in sulate cr fireproof equipment and machinery. The law -further requires that spray-on materials used to in sulate or fireproof buildings, struc tures, pipes, and conduits shall con tain less than IX asbestos on a dry- S k odd weight basis. This vsTwTT)signific-antly reduce emissions to which the gen eral public may l>e exposed, especially in large urban areas. ". . . the Administrator (of EPA) has determined that, in order to pro vide an ample margin of safety to protect the public health from as bestos, it is necessary to control emis sions from major man-made sources cf asbestos emissions into the atmos phere, Irut that it is not necessary to prohibit all emissions. "In this determination, the Admin istrator has relied on the National Academy of Sciences' report on as bestos, which concludes: "Asbestos is too important in our technology and economy for its essential use to! be stopped. But, because cf the known serious effects of uncontrolled inha lation of asbestos minerals in indus try, and uncertainty as to the shape and character of the dose-response curve in man, it would be highly im prudent to permit additional con tamination of the public environment with asbestos. Continued use at min imal risk to the public requires that the major sources of man-made as bestos emission into the atmosphere be defined and controlled.' What is Industry Doing? The Asbestos Information Associa tion/North America reports that, dur ing the past 30 years, the asliestos in dustry has spent millions of dollars to improve mining, milling, and manufac turing methods.* The establishment of safer working conditions lias -been a prime target and this work continues unabated and in close association with government agencies -and independent medical researchers.* The ultimate goals of the asbestos industry arc: Reduction of WT>rk-arca dust to minimum levels; Protection of workers from asbestos-related dis eases; Maintenance of environmental emissions at levels low enough to pre clude public endangennent. r. > r\ 385 JPT (Dec) .... ......... Cat 4 Air Sampling . In order to comply with OSIIA standards and to determine the need for dust control measures, air monitor ing should be conducted in areas where asbestos is regularly handled or used. OSHA standards require that "all determinations of airltome con centrations of asbestos fillers shall Ik* made by the membrane filter method at 400-450.X (magnification) (4 milli., . t* itieTei objective) with phase contrast illumination."10 The equipment for collecting air samples costs less than $400 and is readily available A phase contrast microscope can be obtained for as little as $600, or an existing microscope can be modified for "counting" the asbestos fibers in com pliance with NIOSII criteria." Air samples have been collected and analyzed on a regular basis by the asbestos industry for years. Ex cept for a few applications where dust control is an engineering problem, industry is finding that dust levels are '7 already within acceptable standards or that minimum changes are nec essary to achieve compliance. Al though data on many asbcstos/plastic applications are not available, the summary in Table 4 is typical of our measurements of dust levels during asbestos handling in various types of plants and operations. Tire dust levels reported are ceiling concentrations, and it should be noted that the allow able OSIIA level is 10 fibers/cc. In most cases, the TWA exposure level would be well below OSIIA stan dards. Most of the data were collected before the installation of any special dust-control measures-. Monitoring of ten shows that obviously dusty con ditions are caused hv materials other than asbestos. This docs not preclude the need for controls, but it could change their scope and facilitate com pliance with government regulations, because of "bad press." asbestos is frequently ordered out of use without regard to whether or not a hazard actually exists due to air contamina tion. If acceptable dust levels arc feasible, there is no need to replace asbestos at the expense of product quality or economic penally. Cordon Kvcrctt of MPA points out that inf rotation on the biological effects of asltcstos is very limited and that the effects of many substitutes have not been investigated at all. before as bestos is replaced, it should Ik* cer tain that a safer alternative is avail able." Obviously (here arc inure people exposed to products containing aslics(ns than there arc to raw asliestos filters. As notisl previously, more than 90S of the asliestos used in this conn* try is in products in which the asliestos is "locked in" or Iround with ce ment. plastics, or other hinders, so that there is no release, nr at least no significant release, of fillers in work areas or to the environment. Materials or products with locked-in filters would include: fiocr tile, polyester resins, phenolics, sealants, coatings, brake linings, friction materials, ruliher, roofing compounds, and rein forced plastics. Since an abrading ac tion cm some of these products could release asliestos fillers, appropriate monitoring and/or control measures should lie instituted if it is thought that such action wuuld release filters. Dust-Control Measures 'Asbestos producers and users arc spending a considerable amount of time and money on various dust-con trol measures. Conventional means to achieve minimum dust levels include: filtered ventilation systems on pmcess equipment, local ventilation for saws and similar tools, conversion to a "wetted" operation, leak-proof pack aging, vacuum clean-up, more care in bag disposal and other asbestos waste handling, and automatic bag openers. Unusual innovations include: pel letized asbestos, special packaging, and treated products. Only short-fiber chrysotile is avail able as pellets, but this product serves a KTr^Jortion of the asbestos market. Pellets not only reduce dust during conventional handling but they are also available in bulk hopper cars and can be transferred and used iu totally enclosed systems, barring leaks in the system, dust in work areas is virtually eliminated. Used in bulk, asbestos pellets also reduce shipping costs, eliminate warehouse storage and handling, facilitate automation, reduce . clean-up, and eliminate bag handling and disposal. The pellets inntain no binder and are friable enough to lie dispersed in dry form or in aqueous or resinous systems with conveulioiial high-shcar grinding equipment,'3 S85 JIT (T>cr) Cal 5 Several iypes of special packaging are currently available /and sunnlicnL consider customer requests for unus ual requirements. Tlie floor tile indus try can obtain aslicstos in plastic bags which can !>e added directly to the compounding operation. Aslicstcs in bleached paper bags assembled with water-soluble glue and printed with water-dispersible ink can lie added directly to paper-making (finisHc^ or acoustical tile formulations! Water proof bags are available to pennil slurrying of the aslie.stns in the bug. Wider use ef shrink-filming is being offered to reduce dust during bag handling, transportation, and storage. Although "wetted" asl>estos is not generally available, most suppliers are working with customers to pro vide "dustless" products. When justi fied by market demand, asl>estos can be treated with water, mineral spirits, glycnl, or other materials compatible with the application or system. Conclusion Aslicstos is one of industry's many raw materials which involves a po tential hazard when not used with reasonable respect and rare. Although all forms rf asbestos arc recognized as hazardous to health when inhaled excessively, there is growing evidence that erocidolite and amosite arc more hazardous than ehrysotile. Fortunate ly, the plastics industry uses primarily ehrysotile aslicstos and, in most prod ucts, the fibers are locked-io to pre vent airborne contamination. Al though asbestos dust levels arc gen erally lower than expected---indHstiv--- tinues to(expanJiTarge amounts of a? and money to further improve the. quality of the workplace. Al(lirugh the general public is not cur rently in danger, occupational controls are required to prevent future en vironmental contamination. Chrysotile asbestos is an important and necessary raw material, vital to the nation's safety and economy; and, with proper control, it can lie used safely and in compliance with govern ment regulations. Medical, scientific, government, and industrial personnel must continue to work closely to gether to establish reasonable expo sure limits, provide safe work areas, and eliminate any possibility of public endangerment. Q fs/ieS <2 Ac ;; } f ' r\ H UOUJ/ References'* (1) Enlerlinr. P. F. ami llciulcrvui. V.. Arrh. Environ. Ilnillh, 27, 312 (Nov. 1973). (2) Wagner. |. C.. Ann. Orrnfi. f/vg.. /f.HI (1972), (3) Wright. (. W.. statement Ireforr U.S. Depl. of lalmr. Ouiipalioual Safety and llealili hearing on pro posed nccupaliinial gtlxMix stan dard. Marrli lli. 1972. p. 3. (I) Hammond E. C. and Selikolf. I. `'Relation Of Cigarette Smoking To Risk of Death of Aslrcst is-As-oeiatert Disease among Instilatioii Workers in the L',S.A.." piesrutcd at meeting of the Working Cinnp to Astra Biological Elfect* of As bestos. International Agency for Re search on Cancer. Lvon. France (Oet. A. 1!I72). (5) `Report of the Advisory Committee on Aslrcstos Cancels." Brit. /. Iniluilr. Mat., 30, IK0 (l<J7.1). (6) "AsIk'sIos." Xalionnt Stijrlv Xtvs (Oct. 9. 1973). (7) "National Emission Standards. for Hazardous Air Pol'utaois." hnlanl HrgiUer, 3X, No. Cits. H820 (April li. 1973). <*> ...... ........... *-------- -- --------- maiuikiir |/ (9) Selikolf. 1. J.. Intlntlr. Mnlirinr, 3t>, No. 4. 21 (April 1970). (Ill) "Standard for Kxprtsiin- to Aslrcstos Dost," f'rttrntl l{rgi.\lrr, 37, No. 110. 11320 (June 7. 1972). (11) Bayer. S. (1.. et al. "Eipiipnieot and Procedures for Mounting Mill-pore Kilters and Counting Aslrestos Fibres by Phase-Contrast Microscopy." Bureau of Occup. .Safciv and Health. I'.S. Dept, of Hea b. Edu cation. Ic Welfare (Kelt. 1 *>!). (12) "Arltestos Health Ouestinn Per plexes Experts." Chan. ling. AVies, 18 (Dec. 10. 1973). (13) Myers. J. I... "Calidria Aslrestos Pel lets." ASBESTOS (Oct. 1971;. 385 JPT Dec) Cal 6 Year 1967 I9G8 1969 1970 1971 1972 Table 1--Apparent U.S. Consumption of Asbestos, Tons* Total Chrysotile Amosite ?jn.583 817363 781.321 728.131 758.571 808.55-1 686,1111 (95) * 775.711 (95) 719.708 (90) 695.770 (90) 729272 (96) 791 MU (!I8) 12358(1.7) 20.167 (23) 11.018(1.9) 11561 (2.0) 11380(1.9) f755^(0.9) Crocidolite 11.917(2.1) 13.965(1.7) 10358(13) 8336(12) 6.953(03) 5371 (0.7) (s) Information hawrl on import anil produrtion data from U. S. Bureau of Mines' Mineral* YrarUKtit (b) JYttthi of toul sh*n in piirrfiiltnn, HZS Table 2--Comparative Data for Asbestos Minerals' Formula ___Chryotile Crocidolite Amosite / AnthopKyllite 3MgofiSiO: 2H,0 No.O Fe=0. I.SMgO 5.5FeOf' 7MgO 8SiO, H.O ^ 8S:0,H,0 8SiOsH,0 / Composition. % SiO, MgO FcO Fe.O, A1.0, H.O CaO N'a.O CaO+Na.O Crystals Color Texture Flexibility Hardness. molts ^ Fiber diameter, A Tensile, mpsi Surface charge Resistance to acid Resistance to alkali 37- M 39-11 0-6 0--5 0--2 12--15 0--5 -- -- Fine lilicis Cray grivti Soft silky Vcrv good 2.5-1 180-300 800 Positive Poor Good 19-53 0-3 13-20 17-20 2-5 4=S Brittle fibers nine Harsh Cnod 1 600-900 (iOO Negative (00(1 Cood 19-55 1-7 31-11 2-9 2-5 56--58 28--31 3-12 __ 0-2 1-6 - ---------------0-3 -- -- Prismatic Cray/brown Harsh CkxxI 5J>*6 000.900 200 Negative Prismatic Cray Haish 1 Poor 53-6 1 600-900 ------------''"Negative Cooil Fair Very good Cood j2_ (a) Source*: Modern l*buin KiuuiofNilia (107.1). and F.ncvriopcdia of Chrtn. Treh.. Vol. 2. <y Table 3--Apparent U.S. Consumption(tff~' I Asbestos by General Use Area Areo of Use- Percent of Consumption Construction Floor tile Felt paper Friction and packing Insulation Textiles Other 10 15 15 11 3 i 11 \""7 5 > Tcblo Typical ctir Sampling Results' Typo Plant Or Operation Coiling Concentration Asbestos Fib Floor lilr I'ulu-sler Phetiohc compomitling llaiiilliiii; jtliriiolii' (Biliks ami mmI.iiii> (tjisnm ti'iti|tiiiiniN 1 .1 1-3 25 :: 11 II s 9 niP(Ma)itorNumikh; unt |n|iiiu>ntil (.ailtiiU* (`ttrp.. fiotn jir r ' ' r-. U {J f