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FILE NAME Packings and Gaskets PAG DATE 2000 DOC PAG016 DOCUMENT DESCRIPTION Journal Article - Exposures to Asbestos Arising from Bandsawing Gasket Material FROM : Panasonic PPF U at od TLITELUMU TLITELUMU 19709204417 19709204417 JUL 24.2000 24.2000 5:28 P NO.048 NO.048 10 Applied Occupational and Environmentul Hygiene Volume 15 404 4028000 Copyright '2000 Applied Industrial Hygiene 1047-322X 12.00 .00 041012 C2 C2 Exposures to Asbestos Arising from Bandsawing Gasket Material Health Douglas P. Fowler Fowter Associates Occupational and Environmental Services Inc Redwood City California assigned to work by one of his employers in the 1960s that in- A simulation of bandsawing sheet asbestos gasket mate- rial was performed as part of a retrospective exposure evaluation undertaken to assist in determining causation ofa case of mesothelloma The work was performed by bandsawing a chrysotile asbestos 80 neoprene gasket sheet with a con- ventional Inch woodworking bandsaw inside a chamber Measurements of airborne asbestos were made using con- ventional aroa and personal sampling methods with analy- sis of collected samples by transmission electron microscopy TEM and phase contrast microscopy PCM These were supplemented by qualitative scanning electron microscopy SEM examinations of some of the airborne particles col- lected on the filters In contrawsitth findings from studies ex- amining manual handling installation and removal of gaskets airborne asbestos concentrations from this operation were found to be well above current Occupational Safety and Health Administration OSHA permissibja exposure limit PEL eight weighted average TWA ] and excur- sion limit minute standards Although some encapsu- lation effect of the neoprene matrix was seen on the particles ^finthe airborne dust onencapsulated individual fiber bundies were also seen Suggestions for the implications of the volved the bandsawing of large numbers of gaskets from sheets ofa inpregnated gasker material These gaskets were stacked to form a thick layer of insulation for a specific piece of heating equipment used in the aerospace industry during certain kinds of engine tests . No reports of similar work were found in the industrial ky- giene literature although several reports of exposures during conventional manual handling installation and removal of sin- gle gaskets from piping and ancillary fittings were identified In some of these there were some discussions of the impact of machining work with a few measurements but with no specific testing of bandsawing Accordingly simulation of this specific task was undertaken to fill this gap because the same gasket used by the plaintiwfafs found to still be available commercially The primary issue in question was the probable asbestos ex- posure of the plaintiff during this specific job A secondary issue was the condition of the airborne particles because same experts retained by one side or the other in the asbestos litigation have opined that matrices such as the neoprene in this gasket will encapsulate fibers and fiber bundles thus preventing biologi- cally harmful exposure Other experts of course have different opinions work are given In summary the airborne asbestos concen- trations arising from this work were quite high and point to the nand for careful observation of common sense precautions when manipulation of containing materials even those believed to have limited emissions potential may involve machining operations METHODS AND MATERIALS The material examined was a impregnated sheet gasket 0.3175 cm 1/8 inch thick The asbestos content of the gasket as stated by the manufacturer was 80 percent chrysotile The gasket was delivered from the manufacturer as a tightly Kaywords Asbestos Gasket Bandsaw Exposure rolled 101.6 ^ 365.76 40 ^ 144 inches sheet in corrugated paper wrapping The outer wrapping bore a warning label es An industrial hygiene evaluation was undertaken of the lifelong asbestos exposure of a plaintiff who had fled a lawsuit against a number of defendants formerly or currently involved in the manufacture or distribution of containing ma- terials The plaintiff had been diagnosed with pleural mesothe- lioma Among other jobs over his lifetime the plaintihfadf been shown in Figure 1. Note that the label wamings specifically pro- scribe sawing as performed here Cutting of the sheet to convenient size for bandsawing 101.1061.6 ^ 60.96 cm ^ 24 inches was performed with a Sears Craftsman saber saw with a conven- tional wood sawing blade ~ teeth * 10 teeth per inch tpl The bandsawing was done with a Reliant Model BE 166 16 inch 40.64 cm cutting bandsaw with the original blade 404 07/24/00 19:22 TX NO.5811 P.001 FROM * Panasonic PPF oy + + TETTELTETTU ELUMUN M TELUMN U 12N PLPL 19709204 17 19709204417 1970920441971092074417 JUL.24.2000 JUL.24.2000 JUL.24.2000 5:28 P NO.048 NO.048 Der: ASBESTOS EXPOSURE FROM BANDSAWING GASKET MATERIAL 405 [~ WARNING NAME COMPRESSED ASBESTOS GASKET MATERIAL Category recommend drilling equipment equipment This product contains asbestos and has been defined by the EPA material Category as | NONPRIABLE asbestos containing material In order ccuuttttiinngg gasket recommentdhat all cutting ssuuchch as dies shears strippers strippers blades grinding we maintained as sharp as gaskets from flangewisth an processse approved removal NAME MANUFACTURING COMPANY Address FIGURE I Warning label on ralt of sheeting original size and typography supplied by the manufacturer approximately 3 teeth = 7 tpi operated on the middle speed 609.6 sec : 1200 minute of the three available on the saw The work was done inside a specially constructed chamber built of 0.01524 = 0.006 inch- mil polyethylene sheeting walls with a double layer of 0.0254 cm 10 mil polyethylene for the floor The chamber was constructed with a work area chamber 363.2 cm L ^ 188 cm W x 269.2 cm large= 18.38 m area 43 L x 74 W ^ 106 H * 649 cubic feet and an entrance divided into two smaller chambers The two smaller chambers were a clean room leading from the main laboratory area which led into a dirty room or equipment room leading into the work area chamber Each small entrance chamber was approximately 102 cm x 127 cm x 269 cm 40 ^ 50 x 106 The entire chamber was ventilated during all sawing by drawing air into the entry of the clean room with a Nilfisk Model CS 80 filtered vacuum cleaner placed ar the end of the chamber farthest from the entry The air flow rate was approximately 0.99 1.1c3ubic metars per minute 35 40 cubic feet per minute for an air exchange rate of 3.2-3.7 air changes per hour ACH All sawing work was done by the author wearing disposable garments over street clothes and a properly fitted mask respirator with HEPA filter cartridges It is noted that this level of protection does not meat the modern protective measures required by the Occupational Safety and Health Administration OSHA for cutting containing materials Please refer to the conclusions for recommendations for personal protective measures for this work Three types of sawing were done First the large roll of stiff materia was cut with n saber saw to reduce the pieces for test to approximately 61 cm 102 cm rectangles Secondly the large rectangles were cut on the bandsaw to smaller rectangles each about cm x 15 cm Thirdly each of the smaller rectangles was cut in half on the bandsaw All sawing was of single thicknesses of the gasket material Air samples were taken during the work as personal breath- ing zone samples and area samples The samples were taken by drawing air through mixed cellulose ester filters in three- piece conductive air sampling cassettes 25 millimeter diame- ter 0.43 micrometer nominal pore size inch cow obtained . from Safety Environmental Control Inc. Keene New Hamp- shire Catalog # 203000182 Lot # 9601081 The personal samples were taken with SKC operated sampling pumps ar flow rates of 2.0 and 2.55 liters per minute The area samples were taken with Dawson 110 volt pumps operated at 11.5 and 10.85 liters per minute Each sampling train was calibrated be- fore and after each sample by determining the total volumetric Now rate through the train with a rotameter calibrated less than one month prior to the evaluation with a Spectrex BFM 4000 primary volumetric standard The personal breathing zone samples were taken by placing the sampling cassettes in the author's breathing zone clipped to his clothing so that the opening was near his nose and mouth ' The area sampling locations were at breathing zone height 132 18c3m above floor level with one placed to the left of the bandsaw in the pathway between the saw and the exhaust inlet the other placed behind the bandsaw in location undis- turbed by either the sawing or the air flow Both were approxi- mately 60-90 cm horizontally from the bandsaw blade Three sets of samples were taken During the saber saw cut- ting to reduce the sheet to manageable pieces for bandsaw- ing a single personal sample A was taken from the right side of the operator's breathing zone The second set of samples was takon during the cutting of the two large pieces to smaller pieces approximately 12 cm x 15 cm samples to E. That cutting was interrupted by a power failure for a few minutes as indi- cated on Table I. The third set of samples was taken during the cutting for a few minutes of the 12 cm x 15 cm pieces into halves samples F ta I no O used Each filter was analyzed by phase contrast microscopy PCM Ench was also evaluated forits suitability for further analysis by transmission electron microscopy TEM All ex- cept two samples D and E were deemed to be suitable for such analysis Samples D and E were top heavily loaded for direct analysis Rather than prepare the samples for analysis by an indirect preparation method with consequent splitting of fiber bundles and magnification of the asbestos structure counts the samples were not further analyzed In addition some par- ticles from the samples were examined by scanning electron microscopy SEM and photomicrographs were taken to il- lustrate the condition and characteofr the particles collected sec Figures 2 and 3 for examples RESULTS The results are shown in Table 1. The personal exposures to fibers longer than 5 micrometers m during bandsawing were between 2.2 and 4.9 fibers per milliliter fmL by PCM where the current OSHA eight TWA stendard is 0. mL and the minute excursion limit is 1.0 mL The personal results by TEM were higher 22.2 49.a3sbestos structures per millifter millifter 07/24/00 19:22 TX NO.5811 P.002 PanaP Psaonansoinicc PPPF PF 20 Vet TETTELBHUM TETTELBHUM TETTELBHUM MD PC 19709204417 JUL 24.2000 24.2000 5:29 3 NO.048 NO.048 004 406 D. R. FOWLER ' TABLE I Exposures to airborne asbestos fibers and structures during sawing of inch asbestos sheet gaskei Concentrations Sample # Time Activity A 1321-1333 Saber sawing flattening sheet B 510-1519 Bandsawing . 1524-1545 C 1510-1519 = Bandsawing 1524-1545 511-1515 1524-1545 Bandsawing E 1511-1515 Bandsawing 1524 15451524 1545 F 1555-1601 Bandsawing H 1555-1601 Bandsawing I . 1555-1602 Bandsawing J 1554-1602 Bandsawing : Areal personal Location Personal = R. side BZ Personal R. side BZ Personal = L. side BZ Area - Back of saw Asta Side of saw Area Area Personal Personal Back of saw Side of saw R. side BZ = L. side BZ Duration minutes 12 2 30 3 25 6678 6678 6678 6678 Volume liters 24 60 76.5 287.5 271.3 69 65.1 14 20.4 PCM mL 0,11 TEM total mL 0.62 3.1 22.2 2.2 26.4 0.75 Overload 0.96 Overload 1.8 2.3 4.9 3.1 14,3 . 22.7 49.3 43.5 TEM > 5 m ITIL 0.21 8.2 9.7 Overload Overlord 5.7 7.6 17.6 9.7 FIGURE 2 Scanning electron micrograph @ 500x showing mostly unencapsulated fibers FIGURE 3 Scanning electron micrograph @ 450x showing many encapsulated fibers 07/24/00 19:22 TX NO.5811 P.003 FROM o Panasonic PPF PPF oe vit TEITCLOHUR CLOHUR MD PC 19709204417 JUL 24.2000 24.2000 5:30 PM P NO.048 NO.048 205 ASBESTOS EXPOSURE FROM BANDSAWING GASKET MATERIAL 407 mL for all asbestos squctures and 8.2-17.6 mL for those asbestos Structures longer than 5 m The area samples showed results somewhat lower than the personal samples as would be expected For the PCM analyses the area sample results were between 0.75 and 2.3 mL The TEM arch results were 14.3 and 22.7 mL for total structures and 5,7 and 7.6 mL for those structures longer than 5 min the two samples that could be about 10 minutes would be required With regard to the 30- minueexcursion limit of 0 mL 14 and 6 minutes would be required to exceed it at 2.2 and 4.9 mL respectively If the maximum concentration found for the TEM > mpersonal Bmeasurements 17.6 mL was similarly considered less than 3 minutes would be required to exceed both the P~ ~a,,nd the excursion limit analyzed The findings here are reasonably consistent with the find- ings of others who have studied asbestos exposures during DISCUSSION gasket handling involving machining of gaskels That is that The concentrations of airborne fibers longer than 5 mmeasured by PCM in the breathing zone of the operator during bandsawing of this material are well above the current OSHA Permissible Exposure Limit TWA TWA standard for occupational exposure to asbestos of 0.1 mL and the OSHA minute excursion limit of 1.0 mL For the area samples taken close to the bandsaw the concentrations were all well above the TWA PEL and two of four were above the excursion limit as well The other two samples at 0.75 and 0.96 mL were near to the excursion limit The concentrations of asbestos structures measured by TEM both total and those larger than 5 micrometers in their longest dimension were well above the' fiber concentrations measured by PCM and were significant and substantial The concentrations of airborne structures de- power machining wire brushing old gaskets with a wire disc grinder remove adherent material from the gasketed surface is the most common machining operation may generate appreciable concentrations of airborne asbestos fibers in the range of 0.5 m 5.L 0 by PCM although normal hand cutting does not usually cause such high concentrations As can be seen in Figures 2 and 3 there is support for both sides in the fiber encapsulation dispute Some of the fibers and fiber bundles do appear to be largely encapsulated by the amorphous neoprene matrix However some others are not and one can easily see asbestos fiber bundles that are free of the neoprene Those figures also however show leaat s leat st some of the fibers are agglomerated into large particles that could not under any reasonably foreseeable set of circumstances be termined from the filters with the highest surface loadings of fibers and asbestos structares were lower than for those taken in considered respirable Even though the hand cutting or other manual handling of the same general locations but which had lower loadings This may judicate that there was some obscuration of asbestos particles by overlying particles in the more heavily loaded samples and that these results may therefore understate the schial concentrations The air flow through the chamber 3.2-3.7 ACH was higher than is sometimes found in machine shops or other similar settings and thus these results may understate actual potential exposures for this reason as well However the fact of enclosure will act to restrict dilution and the concentrations this or similar products cannot be guaranteed free from significant risk of asbestos exposure the importance of observing label instructions is illustrated here Any machining operation on any containing product may be accompanied by the production of excessive concentrations of airbome asbestos if sufficient energy is applied to the product Another way of expressing this is to state that friability is always relative to the energy applied Finally this material was purchased for this study in October reported here may thus be higher than would be expocted in A real life setting As can be seen in Table I the saber sawing did not produce measurable airborne asbestos However the detec- 1996. Accordingly users of gaskets are warned that asbestos is not a material of the past but is available on the open market today Given the concentrations measured here and the comparability of these results with measurements of others it will be tion limit of the method was relatively high because of the short important to verify that appropriate precautions are taken 10 pre- sampling period and relatively low concentrations were measured by TEM Based on the ratios of total and > mTEM structures to PCM fibers in the other sets of samples it is es- vent exposure to asbestos if this or similar products are viewed as being so essential that a asbestos substitute cannot be used in their place timated that the PCM concentration in Sample A would have been in the range of 0.04 0.0m 9 L if a sufficient air volume had been collected CONCLUSIONS The periods of exposure at the measured concentrations that would have been required to exceed the OSHA standards using the PCM personal BZ results have been calculated for the extremes of the range of those measurements If one was ex- posed to a concentration of 2.2 mL a period of approximately 22 minutes would suffice to produce an eight TWA expo- sure of 0.1 mL with no other exposure For 4.9 mL only Based on this study it appears likely that similar usage of this similar sheet gaskets may have caused significant asbestos ex- posures during its past and current applications It is unknown how frequently such work was done for is being done now although it has not been reported previously However if many duplicate gaskets were or are to be produced the possibility of bandsaw usage should be investigated because the expected 07/24/00 19:22 TX NO.5811 P.004 FROM = Panasonic PanaPanassoniconic P08P12F6 08126 UTTETTELBAUM UTTETTELBAUM MD PC 19709204417 JUL.24.2000 JUL.24.2000 JUL.24.2000 5:31 5 NO.048 NO.048 006 408 D. POWLER mag- asbestos concentrations from such usage will be orders of nitude above those generated by hand work The most desirable control will be to disallow the use of this or any similar asbestos gasketing material in the workplace Where it must be used the label restrictions given in Figure 1 should be observed at a minimum If machining such as that re- ACKNOWLEDGMENTS The original work was funded by the law firm of Qaliher DeRobertis Nakamura and Ono of Honolulu Hawaii repre- senting the plaintiff and his family The laboratory analyses were performed by Bernard Thomas of the R.J. Lee Group ^ ncin San Leandro California ported here is expected it is recommended that controls similar to those used in this study negative pressure enclosure supple- respiratory and mented by protection protective clothing should be the minimum requirements Where similar kinds of activi- REFERENCES 1. Cheng R.T McDermott H.Exposure to Asbestos from Asbestos ries are carried out in a workplace setting the requirements of the OSHA asbestos regulations should be carefully followed Conventional local exhaust ventilation and enclosure will almost properly cenainly be the most effective contral measure if de- signed and implemented Because of the concentrations found consulted here the relevant OSHA personnel should be prove the measures to be taken to ap- Gaskets Appl Occup Environ Hyg 588 5911991 ) 2. McKinnery W.N Moore R.W Evaluation of Airborne Asbestos Fiber Levels During Ramoval and Installation of Valve Cas- kets and Packing Amer Ind Hyg Assoc loum 532 1993 3. Spence S.K Rocchi P.S.I Exposure to Asbestos Fibers During Gasker Romovil Ann Occup Hyg 583 5818 996 4. Liukonen L.R Still K.R Becken R.R Asbestos Exposure from Based on the TEM concentratreipoorntesd here up to almostu Gasket Operations Industrial Hygiene Branch Naval Regional 50 ml for total structures and up to almost 18 mL for those Medical Center Bremerton WA May 1978 lt > mpressure demand air systems would appear 5. National Institute for Occupational Safety and Health NIOSH supplied to be the only appropriate respiratory protection Even if the Asbestos and Other Pibers by PCM- Method 7400. NIOSH Manuai ee " PCM results are accepted as an appropriate index of risk and it es is assumed that respiratory protection allowing mask concen- as Containing trations as high 0.01 mL may be used some form of supplied ee air system will be requiretdo meet the implicit protection factor requirement 500 course if it is assumed that the Of most ap- propriate workplace exposure standard for asbestos is the usual Lee Group Inc v Lae Group amblent concentration then a protection factor of 5000 will be on needed to make the mask concentration 0.001 mL or below to meet today's ambient concentrations Clearly substitution is of Analytical Methods 4th Edition DHHS NIOSH Pub No. 94- 13 NIOSH Cincinnati OH ( 1994 6. Environmental Protection Agency EPA Materialsin Schools Interim Transmission Electron Microscopy Methods Tille 40 Codoef Federal RegulatPiarot n76s3 SubparEt Appendix A 1987 7. R.J. Personal SEM 3.1 R.J. roeville PA 1996 Mon- 8. Occupational Safety and Health Administration OSHA Asbestos Construction Standard Title 29 Code of Federal Regulations Part the most desirable control and prohibition of power machining 1926.1101 General Industry Standard Title 29 Code of Federal would be next most desirable Regulations Part 1910.1001 1910.1001 1999 ete ee yt ee we a 1 ~ 07/24/00 19:22 TX NO.5811 P.005