Document 822gDQEYpwokxydLZMmkGbEQa

FILE NAME: Union Carbide (UC) DATE: 1973 Dec 20 DOC#: UC046 DOCUMENT DESCRIPTION: Internal Report, Internal Union Carbide Corpv 'Calidria1Asbestos Accepted to r presentation at 1he 32nd Annual Technical Conference of the Society of Plastics Engineers Key 15-16, 1974 Itet for pub l i ca t ion! do not eep y o r excer pt any pof44on of 4 h ic paper CHRYSOTILE ASBESTOS IN PLASTICS John L. Myers "CAUDRIA" ASBESTOS INIDM CARBipf CORPORATION MININS AND METALS DIVISION NIAGARA FALLS, NEW YORK December 20, I973 INTRODUCTION Asbestos has received a great deal of attention and publicity In recent years, especially after It was designated b "target health hazard" by OSHA and a "hazardous air pollutant-" by the EPA. fiany of the articles on asbestos by the press have been emotionally oriented or distorted and in some cases stories have been sensational Ized, based on obvious mis interprttion of facts. The use of half-truths or unsubstantiated statements has led to general confusion ond the unfair castigation Of asbestos and products containing asbestos. The purpose of this paper Is to put the- matter of asbestos use end asbestos hazards in 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. WHAT IS ASBESTOS? Asbestos Is acommerlcal or generic term used to describe six naturally-occurring "asbestiform" minerals that are fibrous, . hydrated metal silicates.. The six varieties are divided into two classes, serpentine and amphibole, based on their crystal structure. Chrysotile is the only member of the serpentine class while the amphiboles include crocldollte, amoste, anthophylIIte, tremolite and actinolite. Chrysotile is by far the most used variety and accounts for over 95i of U.S. consumption, as noted in Table 1. Crocldollte, also known as blue asbestos, is imported from South Africa. Because of Its high mechanical strength and good reslstanco to acids and alkalis, It is used to reinforce.a limited variety of plastics where Its pronounced colon, is not objectionable. Amoslte, also Imported from South Africa, is ; used primarily in thermal Insulation. Although there are some deposits of anthophylIIte In the U.S., most of it is Imported from Finland. It Is used primarily as a filler for polypropylene and In Insulating materials. A comparison of the four varieties of asbestos which ere of commercial Importance Is presented in Table II. It should be noted that there are significant differences between chrysotile and the amphiboles with regard to chemical composition and certain physical properties. WHERE IS ASBESTOS USED AND WHY? ' Asbestos has served mankind for over 100 years in a broad variety of applications. The general areas in which asbestos is used In the United States are shown in Table III. Based on information from asbestos producers and consumption surveys. It is estimated that the plastics industry uses about 1/3 of the 800,000 tons consumed annually, which makes It the largest singlo user of asbestos fiber. The largest uses of asbestos by the plastics Industry are in vinyl/asbestos floor tile ond in phenolic molding compounds.. It Is also used in other plastics such as polypropylene, polyester, nylon, rnelumine, epoxy, silicones and vinyls. Asbestos prvidas a valuable function In such products as brake linings, clutch facings, electrical components, automotive parts, furniture, boats, sealants, coatings, adhesives end nasties. Ths cost Important functions of asbestos in plastics are reinforcement dimensional stability, heat resistance, flow control and general-purpose filling. Most of the functions ore supplied b> short fiber chrysotlle asbestos fiber, although -longer chrysot Ile fibers and other asbostos varieties are sometimes required for particular properties. riA iN TiFF'5 E X H IB IT WHY USE CHRYSOTILE?. Among the several advantages of chrysotile, which set from the amphlbole minerals and account for Its widespread and Increasing usage, are world wide availability, mechanical strength, flexibility, positive surface charge, low iron content, sottneas and low refractive Index. It Is conservatively estimated that chrysotile asbestos is used In over 3,000 applications and In most of these applications it is an essential ingredient for which no replacement is readily available. The Information In Table I shows that the use of chrysotile asbestos and its share of the total market are steadily increasing. This is partly due to technical advances permitting the broader use of chrysotile in plastics and the 9?neTM ` ' ,ne In the use of asbestos In certain fireproofing and insulating materials. In addition, there is increasing evidence croc Ido Iite and amosite are more hazardous t o human health than chrysotile (I). Since 1970 the use of crocidolite in B. itain has been restricted after a panel of experts concluded there was sufficient evidence to suggest other types of f bre should be substituted for crocidolite wherever possible. IZJ WHAT IS THE ASBESTOS HAZARD? ' It Is readily accepted that asbestos, like many other foreign bodies, can cause disabling lung damage (pulmonary fibrosis), commonly referred to as asbeStosis. This disease and bronchogenic carcinoma (lung cancer) are the two ^ t coamon asbestos-related diseases. It is Important to note the,, based on epidemiological data, these diseases have occurred p n ma ri y in workers with high, long-term exposures to "**1 d !t Is of further interest that one noted researcher has r e p o r t e d that neither of these diseases is peculiarly related to o. caused solely by the Inhalation of asbestos fiber (3). Another important consideration is the relation between cigarette cancer as reported by Dr. E. C. Hammond end Or. I. J. Selikoff ) In this study they reported that: It seems clear, then, that lung cancer is uncommon "2 asbestos insulation workers who have no history of cigaretTe smoking end that if the risk is increased, such increase is not great." A Third disease, mesothelioma, has more recently been associated Citi i o r " to asbestos. Hasothelloa. Is on t r o l l y rare cancer of the lining of the chest (pleura) or the obdcmmal cavity (peritoneum). In contrast to tho lung diseases, the.ro is some evidence that mesothelioma can occur after brief exposures to relatively high fiber levels. According to the 3>ineatber Advisory Committee on Asbestos Cencors of the international Agency for Research on Cancer (a division of tho World Health Organization): "There is evidence of an association of mesothellal tumours with oir pollution in tho neighbourhood of crocidollte mines and of factories using mixtures of asbestos fibre types. .The evidence relates to conditions many years ago. There is evidence of no excess risk of mesotheliomas from asbestos air pollution which has existed In the neighbourhood of chrysotile and emoslte mines. There are reported differences on incidence of mesothelioma between urban and rural areas, the causes of which hove not been established. There is no evidence of a risk to the general public at present." (5) The same body quoted above has also concluded that there is at present no evidence of lung damage by asbestos to the general public; and such evidence as there is does not indicate any risk of cancer resulting from asbestos fibers present In water, beverages, food or in the fluids used for the administration of drugs. . While there seems to be general agreement that the -public is not in any.present danger from asbestos, it is also recognized 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. Ouring the past two years, significant legislation-has been enacted by the Federal Government to reduce end control occupational exposure to asbestos fibers and to minimize fiber omissions to the environment. Additional standards or regulations have been proposed or enacted'by many state and local governments. SUNDRY OF OSHA REGULATIONS .. . ` The Wi 11 iams-Steiger Occupational Safety and Health Act of 1970 became effective on April 23, 1971, with the following Congressional purpose: "to assure so f a r e s possible every working man and woman in the Nation safe and healthful working conditions and to preserve our human resources." The Act established the Occupational Safety and Health Administration (OSHA) within tha Department of Labor, which has responsibility for administration and enforcement. Research and related tunctions are handled by the Department of Health, Education and Welfare (HEW) through the National Institute of Occupational Safety and Health (NIOSH). Five million employers and 60 million of the nation's 80 million workers are covered by OSHA. Specifically excluded from coverage are government employees and operations which are protected under other Fedora I health end 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 following five substances were designated to be the focus of ini tic I and concerted efforts by OSK\ and NIOSH: Asbestos, Cotton Dust, Silica, Lead and Carbon Monoxide. At the present time new standards hove been established only for asbestos; although, of the 8,090 toxic substances on the f- * . HIOSH list, only 500 ore covered by standards ond many of these need updating. The new Standard for Exposure to Asbestos Dust was published In the Federal Register, Volume 37, No. 110 Wednesday, June 7, 1972. The basic exposure standard is on PLAINTIFF'S E-hour time-weighted everaqe (TWA) of 5 fibers, longer than 5 EXHIBIT micrometers, per cubic contimster of air. The TV/A limit is r- _ 3 - J o be reduced to 2 fibers per cubic centimeter on July 1, 1976. ~ __ ft peak concentration of 10 fibers per cubic centimeter Is not be exceeded at any time. All of the fiber concentrations ^ are those to which -an employee may be exposed without protective clothing or equipment. The first basic requirement of the new standard Is monitoring to determine whether or not fiber concentrations are in excess of the exposure limits. Some asbestos suppliers provide a monitoring service to customers and a similar service may be obtained from state health department officials, insurance carriers, or private consultants. The law requires that monitoring be repeated as necessary to ensure that employees are not exposed to levels In excess of the exposure limits. Improper interpretation of the regulations has created many misconceptions about the equipment and procedures needed to properly use asbestos. If exposure limits are not exceeded, there are no further compliance requirements except for medical examinations. Medical examinations are required for all employees in any occupation exposed to airborne concentrations of asbestos, fibers. The examinations ere relatively simple and should cost no more than J50 per year, per employee. - Respirators and special-clothing are required In the construction trade for the spray application of insulation and fireproofing materials, and for the removal of such materials. This special protection is not required for any other -use of asbestos unless .exposure limits are exceeded. This is also true for other items such as speciaIly-equipped tools, -change rooms, clothes . laundering and waste disposal. Respirators are not a substitute . for engineering controls but the law allows their use while controls are being Implemented, in special situations where controls are not feasible or adequate, In emergencies, and for Infrequent short-term job assignments. Caution labels are ^ required on products containing asbestos except where the fibers have been modified by a bonding agent or other material to prevent dusting-during any normal subsequent use or handling. Besides raw asbestos fiber, products which require package labeling could include: dry acoustical spray products and Joint cements, unsaturated roofing felt and textiles, end some insulating products made without adequate binders. The labeling of a product does not prohibit its use. It should be noted here that in at least 90? of the products containing asbestos, the fibers are solidly locked into the product thereby presenting little danger of dust generation during normal use and handling of the product (6). EPA STANDARDS Whereas OSHA is responsible for the protection of the worker, the Environmental Protection Agency (EPA) is charged wilh improving tho environment to which the general public is at exposed. On March 31, 1971, asbostos, along with boryl H u m and mercury, was identified as a "hazardous air pollutant" by the Administrator of the EPA. National Emission Standards for asbestos were thon published by the EPA in the Federal Register, Vol. 30, No. 66 - Friday, April 6, 1973. Although no numerical emission standards were established, operating criteria ore prescribed to prevent o r limit asbestos emissions to the outside Dir from asbestos mills, roadways, certain manufacturing operations, building demolition, and the spray-on application of materials used to insulate or fireproof equipment and machinery. The law further requiresthat spray-on materials used to' . insulate or fireproof buildings, structures, pipes, and conduits shall contain less than I? asbestos on a dry weight basis. This should significantly reduce emissions to which the general . public may be exposed, especially in large urban areas. "...the Administrator (of the EPA) has determined that, In order to provide an ample margin of safety to protect the public health from asbestos, it is necessary to control emissions from major man-made sources of asbestos emissions Into the atmosphere, but that It is not necessary to prohibit all emissions. . In this determination, the Administrator has relied-on the National Academy of Sciences' report on asbestos, which concludes: 'Asbestos is too important in our technology and economy for Its essential use to be stopped. But, because of the known serious effects of uncontrolled inhalation of ' asbestos minerals in industry and uncertainty as to the shape . and character of the dose-response curve in man, It would be highly imprudent to permit additional contamination of the public enviroament with asbestos. -Continued use at minimal risk to the public requires that the major sources of man-made asbestos emission into the atmosphere be defined and controlled."'. (7) ' WHAT IS INDUSTRY DOING? ' The Asbestos Information Assoclatlon/North America reports that, during the past 30 years, the asbestos industry has spent millions of dollars to improve mining, milling, and manufacturing methods (3). The establishment of safer working conditions has been a prime target and this work continues unabated and in close association . with government agencies and independent medical researchers (9). The u7timate goals of the asbestos industry are: --- Reduction of work-area dust to minimum levels. -- 1Protection of workers from asbestos-related diseases. -- :Maintenance of environmental emissions at levels low enough to preclude public endangerment. AIR SAMPLING In order to comply with OSHA Standards and to determine the need for dust control measures, air monitoring should bo conducted In areas where asbestos Is regularly handled or.used. OSHA Standards require that "all determinations o f airborne concentrations of at asbestos 400-460X fibers shall be (magnification) m1a4dmei bDyimtehteermeombbjreacnteivfei)ltweirtmhelp.h\oadse contrast Illumination." (10) The equipment for collecting sir samples costs less than $400 and is readily available. A phase i * '"`narmu V . . ' ' contrast microscope can be obtained for as little as $600 or an existing microscope can be modified for "counting" the asbestos fibers in compliance with NIOSH criteria (II). Air samples have been collected and analyzed on a regular basis by the asbestos industry for years. Except for a few applications N M N H S 5 & where dust control is an engineering problem, industry is finding PLAINTIFF'S 1 dust levels are already within acceptable standards.or that EXHIBIT Iminimum changes are necessary to achieve compliance. Although /, - I data on many asbestos/plastics appI cations, are not available, the 1 I summary in Table IV is typical of our measurements of dust levels ^ a a ^ ^ d u r i n g asbestos handling In various types of plants and operations. The dust levels reported are Ceiling Concentrations and it should . be noted that the allowable OSHA level Is 10 flbers/cc. In most . cases, the TWA exposure level would be well below OSHA Standards. Most of the data were collected before the installation of any special dust control measures. Monitoring often shows that . obviously dusty conditions are caused by materials other than asbestos. This does not preclude the need for controls but It could change their scope and facilitate compliance 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 contamination. If acceptable dust levels are ` feasible, there is no need to replace asbestos at the expense of product quality or economic penalty. Mr. Gordon Everett of EPA . points out that information on-the biological effects of asbestos . is very limited and that the effects of many substitutes have not been investigated at all. Before asbestos is replaced, ft . should be certain that a safer alternative Is available (12). Obviously there are more people exposed to products containing asbestos than there are to raw asbestos fibers. As noted ' previously, over 90? of the asbestos used In this country is in products in which the asbestos rs "locked In" or bound with cement, plastics or other binders so that there Is no release, or at least no significant release, of fibers In work areas or to _ the environment. Materials or products with locked-ln fibers * would include: floor tile, polyester resins, phenolics, sealants, coatings, brake linings, friction materials, rubber, roofing compounds . and reinforced plastics. Since an abrading action on some of these products could release asbestos fibers, appropriate monitoring . and/or control measures should be instituted If It is thought that such action would release fibers. DUST CONTROL MEASURES Asbestos producers and users are spending a considerable amount of time and money on various dust control measures. Conventional means to achieve minimum dust levels include: filtered ventilation systems on process equipment, local ventilation for saws end similar tools, conversion to a "wetted" operation, leak-proof packaging, vacuum clean-up, more care in bag disposal and other asbestos waste handling, and automatic bag openers. Unusual innovations include: pelletized asbestos, special packaging, and treated products. Only short-fiber chrysotlle Is available as pellets, but th Po is ll pr o1s o duc not t o serv nly es a reUu fair co du p st o rt du ion ring ofc otnhvee natsiboennslt o s narkot. handling but they ore also available in bulk hopper cars and can be transfer^d and used in totally enclosed systems. Barring leaks in the system, dust in work areas is virtually eliminated. Used in hulk, asbestos pellets also reduce shipping costs, eliminate warehouse storage and handling, facilitate automation, reduce clean-up, end eliminate bag handling and disposal. The pellet contain no binder and are-friablo enough to be dispersed In dr)1 form or In aqueous or resinous systems with conventional high- shear grinding equipment (13). . Several types of special packaging are currently available end suppliers consider customer requests for unusual requirements. The floor tile industry can obtain asbestos in plastic bags which can be added directly to the compounding operation. Asbestos In bleached paper bags assembled with water-soluble glue and printed with water-dispersible ink can be added directly to paper-making furnishes or acoustical celling tile formulations. Water-proof bags ere available to permit slurrying of the asbestos in the bag. Wider use of shrink-filming is being offered to reduce dust during beg handling, transportation end storage. Although "wetted" asbestos is not generally available, most suppliers are working with customers to provide "dustless" products. When justified by market demand, asbestos can be treated with water, mineral spirits, glycol or other materials compatible with the.appIcation or system. ` CONCLUSION Asbestos is one of industry's many raw materials which involves a potential hazard when not used with reasonable respect and care. Although all forms of asbestos are recognized os hazardous to health when inhaled excessively, there is growing evidence . that crocI doi ite and amosite ere more hazardous than chrysotile. Fortunately the plastics Industry uses primarily chrysotile asbestos . and In most products the fibers ere locked-In to prevent airborne contamination. Although asbestos dust levels.are generally lower than expected. Industry continues to expend large amounts of time end money to further Improve the quality of The workplace. Although the general public is not currently in danger, occupational* controls ere required to prevent future environmental contemination. Chrysotile asbestos is an important and necessary raw material, vital to the nation's safety and economy; end, with proper control, it can be used safely and in compliance with government regulations. Medical, scientific, government, and industrial personnel must continue to work closely together to establish^ . reasonable exposure limits, provide safe work areas, end eliminate any possibility of public endangerment. > REFERENCES: 1. Enterline, P. E. and V. Henderson, "Type of Asbestos and Respiratory Cancer In the Asbestos Industry," Arch. Environ. Health/Vol. 27, pp. 312-317 (Nov. 1973). . 2. Wagner, J. C., "Current Opinions On The Asbestos Cancer Problem," Ann. Occup. Hyg., Vol. 15, pp. 61-64 (1972). 3. Wright, G. W., Statement before U.S. Dept, of Labor, Occupational Safety and Health Hearing on Proposed Occupational Asbestos Standard, p. 3 (March 16, 1972). 4. Hammond, E. C. and I. J. Selikoff, "Relation Of Cigarette Smoking To Risk of Death Of Asbestos - Associated Disease Among Insulation Workers In The United States," presented at the meeting of the Working Group to Assess Biological Effects of Asbestos, International Agency for*Research on Cancer, Lyon, France (October 4, 1972). 5. "Report of The Advisory Committee on Asbestos Cancers," Brit. J. industr. Med., Vol. 30, pp.180-186 (1973). 6 "Asbestos," National Safety News (October 9, 1973). 7 "National Emission Standards for Hazardous Air Pollutants,". Federal Register, Vol. 38, No.. 66, p. 8820 (April 6, 1973). 8' "Protecting The Asbestos Worker," Booklet.No. I0ID37, p. 5, The Asbestos Information Association/North America. 9. Selikoff, I. J., "Partnership For Prevention," Industrial Medicine, Vol. 39, No. 4, pp. 21-25 (April 1970). 10. "Standard For Exposure To Asbestos Dust," Federal Register, Voi. 37, No. 110, p. 11320 (June 7, 1972). - 11. Bayer, S. G. et al, "Equipment and Procedures For Mounting Millipore Filters and Counting Asbestos Fibres By Phase Contrast Microscopy," Bureau of Occupational Safety and Health, U.S. Dept, of Health, Education, and Welfare, (February 1969). 12. "Asbestos Health Question Perplexes Experts,'? Chemical and Engineering News, pp. 18-19 (December 10, 1973) 13. Myers, J. L., "Calidria Asbestos Pellets," ASBESTOS (October 1971) TABLE t APPARENT U.S. CONSUMPTION Of ASBESTOS, TCMS* () of TotI Shown In Parentheses) * PLAINTIFF'S i EXHIBIT Year 1067 1968 1969 1970 1971 1972 Totai 720563 817363 764321 728131 758571 808554 Chrvsottle Amoslte 686044(95) 1 12556(1.7) 775711(95) 20467(2.5) 749708(96) 14618(1.9) 695770(96) 14261(2.0) 729272(96) 14580(1.9) 791020(98) 7I25(P.9) Crocldollte 149)7(2.1) 13965(1.7) 105580.3) 69360.2) 6953(0.9) 5374(0.7) Information based on Import and production data from United States Bureau of Nines Minerals Yearbooks. TABLE II FORMULA COMPARATIVE DATA FOR ASBESTOS MINERALS a? CHRTSOTILE CROCIPOLITE . AKOSITE ' 3MgO* 2S lOj*2H^0 NepO- FejOj* 3FeO 8SIP2*H20 l.5MgO*5.5FeO* 8SI0rM20 AMTHOPHVLLITE TtfcO-BSIOyHjO COMPSOISOI2TION,* MgO FeO AFl22033 H7O C0 NajO CaOtNajO 37-44 39-44 0-6 0-5 0-2 12-15 0-5 - 49-53 0-3 13-20 : 17-20 ' - 2-5 -- 4-8 - 49-53 1-7 34-44 2-9 2-5 4 ' ' 0-3 56-58 . 28-34 3-12 0-2 1-6 -- -- - CRYSTALS COLOR TEXTURE FLEXIBILITY HARDNESS, Mohs FIBER DIA., A TENSILE, Mosl SURFACE CHS. RES. 10 ACID RES. TO ALK. Fine Fibers Cray/Green Soft/SIIky Very Good 2.5-4 180-300 BOO Positive Poor . Good Brittle Fibers Blue Marsh Good 4 600-900 600 Negative . Good ` Good Prismatic Crystals Grey/Brovn Harsh Good 5.5-6 600-900 200 Negative Good Fair Prismatic Crystals Gray ` Harsh Poor 5.5-6 600-900 <4 Negative Very Good Good Source: Modern Plastics Encyclopedia! 1972-3), and Encyclopedia of Chemical Technology, Volvao 2, p. 136(1948). TABLE I I I APPARENT U.S. CONSUMPTION OF ASBESTOS BY GENERAL USE REAS . Area of Use % of Consumption* Construction Floor Tile Felt and Paper Friction i Packing Insulation Textiles Other . ... -40 . 15 15 14 3 2 II Author*s Interpretation of data from the USBM Minerals Yearbook - Asbestos-I972, the Asbestos Information Association/ North America, and personal communications with Mr. R. A. Clifton of the USBM. TABLE IV TYPICAL AIR SAMPLING RESULTS Type Plant or Operation Floor Tile ` Polyester Phenolic Compounding Handling Phenolic Caulks and Sealants Gypsum Compounds Celling Concentration,*123 Asbestos Flbers/cc 1- 3 . 1-3 2- 5 3 - 14 0-8 2-9 Source: Union Carbide Corporation, from air monitoring reports.