Document 4vgggbyzLeJw4dgbyj63XLnMV

CHRYSOTILE ASBESTOS IN PLASTICS John L. Myers "CALIORIA" ASBESTOS UNION CARBIDE CORPORATION MIKING AND METALS DIVISION NIAGARA FALLS, NEW YORK Presented on May 14, 1974 at the J2nd Annual Technical Conference of the Society of Plastics Engineers in San Francisco. DEFENDANT'S EXHIBIT tUCC,42Z) UCASB00764523 UC DR 6/03 CD1 00002600 SC-ELEC-05930 INTRODUCTION' ' ' Asbestos has received a great deal of attention and publicity In recont years, especially after It was designated a "target health hazard" by OSHA end a "hazardous air pollutant" by the EPA. Many of the articles on asbestos by the press have b9an ' emotionally oriented or distorted and In some cases stories have bean sensationalized, based on obvious misinterpretation of facts. The use of half-truths or unsubstantiated statements has led to general confusion 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 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 usb 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 a coroner Ical or generic term used to describe six naturally-occurring "asbestlform" minerals that are fibrous, hydrated metal silicates. The six varieties are divided Into two classes, serpentine and amphlbole, based on their crystal structure. Chrysotlle Is the only member of the serpentine class while the amphlboles Include croctdollte, amostte, anthophylIIte, tronollte and actlnollte. Chrysotlle Is by far the most used variety and accounts tor over 955 of U.S. consumption, as noted in Table I. Crocldollte, also known as blue esbestos. 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'6f anthophyl I ite in theU.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 are of commercial Importance is presented in Table II. It should be noted that there ere significant differences between chrysotlle end the. amphlboles with regard to chemical composition and certain physical properties. WHERE IS.ASBESTOS USED ANO WHY? Asbestos has served mankind for over 100 years In a broad variety of'applleaf ions. 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 600,000 tons consumed annually, which makes it the largest single user of asbestos fiber. The largest uses of asbestos by the plastics Industry are In vinyl/asbestos floor tila and In phenolic molding compounds. It Is also used in other plastics such as polypropylene, polyester, nylon, melamine, epoxy, silicones and vinyls. Asbestos provides UCASB00764524 UC DR 6/03 CD1 00002601 a valuable .function in such products as brake linings, clutch facings, electrical components, automotive parts, furniture, boats, sealants, coatings, adhesives end mastics. The most important functions of asbestos in plastics are reinforcement, dimensional stability, heat resistance, flow control and general-purpose filling. Most of the functions are supplied by short fiber chrysotile asbestos fiber, although longer chrysotile fibers and other asbestos varieties are sometimes required tor particular properties. WHY USE CHRYSOTILE? Among the several advantages of chrysotile, which set It apert from the amphlbole minerals and account for its widespread and Increasing usage, era world wide availability, mechanical strength, flexibility, positive surface charge, low Iron content, softness 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 availeble. The Information In Table I shows that the use of chrysotl le asbestos and its share of fhe total market are steadily increasing. This is partly due to technical advances permitting the broader use of chrysotile In plastics and the general decline In the use of asbestos in certain fireproofing and insulating materials. In addition, there Is Increasing evidence that crocldolite and amoslte are more hazardous to human health than chrysotile (I). Since 1970 the use of crocidol Ite In Britain has been restricted after a panel of experts "concluded there was sufficient evidence to suggest other types of fibre should be substituted for crocidoiite wherever possible." (2) WHAT IS THE ASBESTOS HAZARD? It is readily accepted that asbestos. Ilka many other foreign bodies, can cause disabling lung damage {pulmonary fibrosis), commonly referred to as asbestosls. This disease and bronchogenic carcinoma Clung cancer) are the two most common asbestos-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 of further Interest that one noted researcher has reported that neither of these diseases is peculiarly related to or caused solely by the inhalBtion of asbestos fiber (3). Another important consideration is the relation between cigarette smoking and lung cancer as reported by Or. . C. Hammond end Dr. I. J. Sellkott (4). In this study they reported that: "It seems clear, then, that lung cancer is uncommon among asbestos insulation workers who have no history of cigarette smoking and that if the risk is increased, such increase is not great." A third disease, mesothelioma, has more recently been associated with persons exposed to esbestos. Mesothelioma is an extremely rare cancer of the lining of the chest (pleura) or the abdeninai cavity (peritoneum). In contrast to the lung diseases, there is some evidence that mesothelioma can occur after brief exposures to relatively high fiber levels. 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C 0 0 O 4ao -o CO ruree C 4* 4re --o 5 0o 6 ro0ce 4ro--e u re &0 o rree v< 4o- (0 fN I/) C0 o CD D i NIOSH list, only 500 are covered by standards and nany of these need updating. The new Standard for Exposure to Asbestos Dust ties published In the Federal Register, Volume 37, Mo. 110 on Wednesday, June 7, 1972. The basic exposure standard is an 6-hour time-weightad average (TWA) of 5 fibers, longer than 5 micrometers, per cubic centimeter of air. The TWA limit is to be reduced to 2 fibers per cubic centimeter on July I, 1976. A peak concentration of 10 fibers per cubic centimater Is not to 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 n9t standard Is monitoring to determine whether or not fiber concentrations are In excess of the exposure limits. Seme asbestos suppliers provide a monitoring service to customers and e 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. Wed/cel examinations are required for all employees in any occupation exposed to airborne concentrations of asbestos fibers. The examinations are relatively simple and should cost no more than S50 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 specio11y-equipped tools, change roams, 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, end for Infreouont 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 materiel to prevent dusting during any normal subsequent use or handling. Besides raw asbestos fiber, products which require peckag9 labeling could include: dry ecoustical spray products and joint cements, unsatureted roofing felt and textiles, and 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 Bsbestos, the fibers are solidly locked into the product thereby presenting tlttlo dangor of dust generation during normal use and handling of the product (6>. . EPA STANDARDS Whereas OSHA is responsible for the protection of the workar, the Environmental Protection Agency lEPA) is charged with Improving the environment to which the general public Is UCASB00764527 UC OR 6/03 CD1 00002604 exposed. On-Karch 31. 1971, asbestos, along with beryllium and mercury, was identified as a "hazardous air pollutant" by the Administrator of tba CPA. Notional Emission Standards for asbestos were then published by tha EPA In the Federal Register, Voi. 38,. No. 66 - Friddy, April 6. 1973. Although no numerical emission standards were established, operating criteria are prescribed to prevent or limit asbestos emissions to the outside sir 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 requires that spray-on materials used to insulate or fireproof buildings, structures, pipes, and conduits shell contain less than \% asbestos on e dry weight basis. This should significantly reduce emissions to which the general public may be exposed, especially in large urban areas. "...the Administrator lot the CPA) has determined that. In order to provide an ample margin of safety to protect the public health from asbestos, 1+ 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 oh the National Academy of Sciences' report on asbestos, which concludes: 'Asbestos Is too important in our technology and economy tor Its essentia) 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 environment 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 control led.'" 17) WHAT IS INDUSTRY OPING? The Asbestos Information Associatlon/Horth America reports that, during the past 30 years, the asbestos Industry has spent millions of dollars to improve mining, milling, ond manufacturing methods 13). 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 ultimate goals of the asbestos industry are: ----- Reduction of work-area dust to minimum levels. . ----- Protection of workers from asbestos-related diseases. ----- Maintenance of environmental emissions at levels low enough to preclude publIc endangermant. AIR SAMPtlfO In order to comply with 05HA Standards and to determine the need tor dust control measures, air monitoring should be conducted in areas where asbestos is regularly handled or used. GSHA Standards require that "all determinations of airborne concentrations of esbestos fibers shall be made by the nambrane filter method at 400-450X (magnification) (4 millimeter objective) with phase contrast illumination." (10) The equipment for collecting air samples costs less than S<i00 ar,d is readily available. A phase UCASB00764528 UC DR 6/03 CD1 00002605 contrast microscope can be obtained for as tittle as S600 or an existing microscope can be modified for "counting" toe 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 where dust control Is an engineering problem, industry ts finding that dust levels are already within acceptable standards or that minimum changes are necessary to-achleva compliance. Although data on many asbestos/pissttcs applications are not available, the summary in Table IV is typical of our measurements of dust levels during asbestos handling in various types of plants and operations. The dust levels reported are Celling Concentrations and ft should be noted that the allowable OSHA level Is 10 flbers/ce. 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 ere caused by materials other than asbestos. This does not preclude the need for controls but It mould 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, tt 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 is "locked in" or bound with cement, plastics or other binders so that there Is no release, or of least no significant release, of fibers In work areas or to the environment. Materials or products with locked-in 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. OUST 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 and 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 * UCASB00764529 UC DR 6/03 CD1 00002606 this product serves a fair portion of the asbestos market. Pellets not only reduce dust during conventional handling but they are also available in bulk hopper cars and can bo transferred and used in totally enclosed systems. Barring leaks In tho 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 contain no binder and are friable enough to be dispersed in dry form or in aqueous or resinous systems with conventional highsheer grinding equipment (13). Several types of special packaging are currently available and 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 wate'r-dlspersible Ink can be added directly to paper-making furnishes or acoustical ceiling tile formulations. Water-proof bags are available to permit slurrying of tho asbestos In the bag. Wider use of shrink-filming is being offered to reduce dust during beg handling, transportation and 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 materiel? compatible with the application 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 as hazardous to health whan Inhaled excessively, there is growing evidence that crocidolite and amosite are more hazardous than chrysoti le. fortunately the plastics industry uses primarily chrysotile asbestos and in most products the fibers are locked-in to prevent airborr.a contamination. Although asbestos dust levels are generally lower than expected. Industry continues to expend large amounts Of time and money to further Improve the quality of tho workplace. Although the general public is not currently In danger, occupational controls are required to prevent future environmental contamination. Chrysotile ashestes Is an important and necessary raw material, vital to the nation's safety end economy: and, 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, and eliminate any possibility of public endangerment. UC OR 6/03 CD1 00002607 t UCASB007B4530 REFERENCES: 1. Enter line, P. E. and V. Henderson, "Type of Asbestos and Respiratory Cancer In the Asbestos Industry," Arch. Environ. Heal th/Vo 1. 27, pp. 312-317 (Nov. 1973). 2. Wagner, J. C., "Current Opinions On The Asbestos Cancer Problem," Ann. Occup. Hyg., Vol. IS, pp. 61-64 (1972). 3. Wright, 6. W., Statement before U.S. Oept.of Labor, Occupational Safety and Health Hearing on Proposed Occupational Asbestos Standard, p. 3 (March 16, 1972). 4. Hammond, E. C. and I. J. SolIkoff, "Relation Of Cigarette Smoking To Risk of Oeath Of Asbestos - Associated Oisease 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 Comnlttee 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 Associatfon/Norfh America. 9 Setlkotf, 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, Vol. 37, No. 110, p. 11320 (June 7, 1972). 11. Bayer, S. G. et al, "Equipment and Procedures For Mounting MilI(pore Filtors and Counting Asbestos Fibres By Phase Contrast Microscopy," Bureau of Occupational Safety and Health, U.S. Oept. of Health, Education, and Welfare, (February 1969). 12. "Asbestos Health Question Perplexes Experts," Chemical end Engineering News, pp. 18-19 (Oecember 10, 1973) 13. Myars, J. L., "Call dr Ia Asbestos Pallets," ASBESTOS (October 1971) UC DR 6/03 CD1 00002608 UCASB00764531 I ofpAHQtr u.s. comuMpnoH of asbestos, tons* If of Total Shorn in P*rtnfhd**l T--f 1862 1968 1949 1920 1911 192* Total 720363 012363 764321 *20131 730321 000334 Chmotlta 6060*4193) 773211(93) 749706(96) 693270(96) 729*72(96) 791020(98) A*o*lt* 12330(1.7) 20*67(2.3) 14610(1.9) 14201 (Z.0) 14300(1.9) 7l2$(p.9) Crocldolttt 14917(3.1) 13983(1.7) lOlSfldJ) 6936(1.2) 6933(0.9) 5374(0.7) infomotion Mttl an loport and production data Im United Slate* Bureau el Mine* Mineral* Tocreooks. TA8U II CCWMWTIVt DATA FW ASBESTOS MWBWLS OfttSOTILE CA0CI00LITE AMOSITT AHMPHYUITE rawuu S^O-ZSIOj'ZH^) NajOFayOy3Fe0* 6SI02-N20 1 .SMgO- S.SFoO8SI02-H20 TMgO-eSIOfMjO OOWOSITIOH.J SIO] MgO ro 7*203 AljOj HJ0 CaO S^Ka^O 37-44 39-44 0-0 0-3 0-2 12-13 0-3 - *9-33 0-3 13-20 17-20 2-3 *9-33 1-7 34-44 2-9 2-5 >3 36-30 28-34 3-12 0-2 1-6 - CRYSTALS COLOR TEXTURE FLEXIBILITY HMBMESS. Moh* new pia-, X TENSILE. Mjsl SWFACC OC. R3. TO ACID MU. 20 ALA. Pina Fiber* Qry/0rn soit/siikr Very Good 2.3-4 180-300 600 PmIHh Poor Good Brlttla flbara eiv ittrjh Good 4 600*900 600 Megatl+O Good Good Prlssatlc Cryittli . Oray/dram Karsh Good 3.5-6 ' 600-900 zoo Magatlva Oood Fair Prlsaatic Cryitt$ Gray lann Poor 5.3-6 600-900 <4 Magatleo V7 Good Good Soorce: Hotfaro lliillu CncycloM4le<l972-3), and Encyclopedia of Chonical Technology, Volina 2. . 136(19*6). UC DR 6/03 CD1 00002609 UCASB00764532 I TABLE 111 APPARENT U.S- CONSUMPTION OF ASBESTOS BY GENERAL USE AREAS Area of Use i of Consumption* Construction Floor Tlle Felt and Paper Friction 4 Packing Insulation Textlles Other 40 IS 15 14 3 2 II Author's Interpretation of ifata from the USBM Minerals Yearbook - Asbestos-1972, the Asbestos Information Association/ North America, and personal communications with Mr. ft. A. Clifton of the USBM. table iy TYPICAL AIR SAMPLING RESULTS Type Plant or Operation Floor Tile Polyester Phenolic Compounding Handling Phenolic Caulks and Sealants Qypsum Compounds CellIng Concentration, Asbestos FTbers/cc 1-3 . 1-3 2-5 3-14 0-8 2-9 ' Source: Union Carbide Corporation, from air monitoring reports. UC DR 6/03 CD1 00002610 UCASB00764533