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FILE NAME: Georgia Pacific (GP) DATE: 1973 Nov 19 DOC#: GP005 DOCUMENT DESCRIPTION: Internal Report - Gypsum Association - Evaluation of Exposure to Asbestos During Mixing and Sanding of Joint Compounds EVALUATION OF EXPOSURE TO ASBESTOS DURINC MIXINC AND SANDING OF JOINT COMPOUNDS GYPSUM ASSOCIATION Denver, Colorado November 19, 1973 J # i EVALUATION OF EXPOSURE TO ASBESTOS DURING MIXINC AND SANDING OF JOINT COMPOUNDS CYPSUM ASSOCIATION Denver, Colorado INTRODUCTION The Cypsum AiioelatloD retained Ceorge D. Clayton and Associates to conduct an induatrial hygiene aurvey at a teat aite located in Den ver, Colorado. The purpose of the survey vaa to determine the con centrations of airborne asbestos to vhleh workers were exposed dur ing mixing and sanding of joint cement compounds and to interpret the results in terms of potential health hazards with particular refer ence to regulations promulgated under authority of the Occupational Safety and Health Act of 1970. This study was conducted on November 19, 1973 by Mr. Robert D. Soule of Clayton and Associates. Results of that study are reported herein. - BACKGROUND The Cypsum Association, located at 1603 Orrington Avenue in Evanston, Illinois is a trade association which represents ten to fifteen in dustrial companies which are engaged in the manufacture of products Incorporating gypsum or gypsum-like materials. As with most indus trial concerns, the activities of the Gypsum Association have become more broad with the passage and implementation of federal regulations such as the Metal and Non-Metallic Mine Safety Aet and the Occupa tional Safety and Health Aet. Technical committees composed of per sonnel from companies comprising, the Cypsum Association have been es tablished with particular Interest in the occupational safety and health field. Of particular concern in this reapect'vas the poten tial hazard associated with exposure of workers to airborne asbestos during mixing and sanding of compounds used to seal cracks and joints formed during installation of wallboard material. Although the spe cific formulations used by the various companies manufacturing and supplying the joint compound vary,it is understood that essentially all of them incorporate asbestos in the product whether as a dry com pound or a ready-mix product. ` .. In order to evaluate the exposure of workers to asbestos during han dling and use of the joint compound products, the Cypsum Association decided to undertake a test program during which several products would be mixed and sanded. George D. Clayton and Associates was re tained to collect and analyze samples which would represent the ex posure of workers engaged in the study. The tests were performed on . November 19, 1973 in a development of townhouses known as King's Mill Tovnhouses, which were under construction in a suburban area north of Denver, Colorado. POTENTIAL HEALTH HAZARD ASSOCIATED WITH EXPOSURE TO ASBESTOS Asbestos is a generic term referring to various mineral sllieates. The types used most widely la industrial applications Include ehrysotile, or "white asbestos" (a hydrated magnesium silicate']), amoslte,_ 2 r - or "grey asbestos" (an iron nagneilun silicate), crocidolite, or "blue asbestos" (a aodium iron silicate), treraollte (a calcium magneaium silicate), and anthophyllite (another iron magneaium sili cate). Of theae, ehrysotile accounts for over 90 percent of the __total uaage of aabestos in this country, with amoalte and crocido lite being the only other types used to any significant extent. 'Asbestos exists naturally in bundles of extremely fine fibers -which can be subdivided easily into many smaller fibers. The potential health hazard associated with exposure to asbestos is that of inhala tion of airborne fibers resulting ln'a type of pneumoconiosis referred to as "asbestosls." Small asbestos fibers cat pass readily through the upper respiratory tract and be deposited in the terminal bronchi oles of the lung. There, they produce a local irritation which the body attempts to overcome by Initiating a tissue response resulting in the encapsulation of the fibers and consequent formation of "as bestos bodies." If sufficient quantities of fibers are Inhaled over an extended period of time, a generalized diffuse peribronchiolar fibrosis can develop. This pulmonary fibrosis can impair the trans fer of oxygen across the aveolar membranes and result in respiratory Insufficiencies, or even eardlae failure. Zt has been determined, through toxicological and epidemiological studies, that long fibers, 20 to SO micrometers in length, are most active in the production of the fibrosis. Fibers shorter than about two micrometers in length, are practically vithout an irritating effect. There is some evidence that other minerals having fibrous characteristics can produce simi lar reactions. Many recent studies have indicated an association between exposure to asbestos in both industrial and urban atmospheres and an increase in a relatively rare type of lung cancer-known as mesothelioma. Al though it has not been possible to establish a connection with asbes tos in all eases of this disease, there is a strong correlation be tween exposure to croeidolite and occurrence of mesotheliomas. Other types of asbestos have been implicated to a much lesser extent. how ever, this "new hazard" has received much public attention because it has been suggested that very minimal, non-oecupational exposure can be sufficient to produce the disease in some individuals.. For many years the American Conference of Governmental -Industrial Hy gienists has recommended a threshold limit value (TLV) of five mil lion particles per cubic foot of air (mppcf) for all types of asbes tos-bearing dusts containing less than one percent crystalline silica.. The threshold limit value is defined as the concentration of an air borne contaminant to whleh it is believed that nearly all workers can be exposed for continuous and repeated work days without experiencing adverse effects. The TLV of five mppcf was based on the impinger sam pling technique which was selected as the standard method in the early epidemiological studies of occupational exposure to asbestos. - With this method, air is drawn through an impinger containing water and the total particles (both grains end fibers) in an aliquot of the sample,are counted uslnglight-fleId microscopic techniques. Within reeent years, because of the increaslng concern about-asbestos in the environment and the resulting need for a more relevant sam- _ pllng method, the American Conference of Governmental Industrial  * lu M J II J Hygienists has proposed * TLV of five fiber'a* (greiatcefr thh-.W.*-*-W-^- !i|WJLHiyD7^ meters in length) per cubic centimeter of eir. This standard is base on the membrane filter technique with aetual microscopic fiber count ing at 400-450X magnification using phase contrast illumination. .The Occupational Safety and Health Administration (OSHA) has estab lished the above concentration (five fibers, greater than five micro meters in length, per cubic centimeter of air) as an emergency itandard and have announced that, effective July 1, 1976, the acceptable limit for an eirhr-hour. time-weighted average exposure will he reaccei z : :r; fibers or. Z z affirirs. JJSa has established :b.e con centration of ten fibers (.greater chan five micrometers in length) per cubic centimeter of eir as an acceptable celling concentration. Workers shall not be exposed .to concentrations of asbestos in excess o f this value, regardless of duration of exposure. SAMPLING AND ANALYTICAL METHODS The air sampling conducted to evaluate exposures of workers to asbes tos vss all of the "breathing tone" type. These samples were col lected by drawing air through 37-mm diameter membreae filters (Millipore Type AA) at a rate of about two liters per minute using small, battery-operated pumps (Mine Safety Appliances Company, Model G). The sampling units were worn by the workers engaged in either mixing or sanding the joint compound; the pump was attached to the belt and the sampler head fattened on the outside of the worker's shirt at approximate breathing zone height. Thus, these samples were repre sentative of the time-weighted average conditions to which the men were exposed during the sampling period. The sampling heed consisted of e three pieee eeesette (Mllllpore); during sampling the faee cap was removed end the filter was used in an "open faee" mode.with Che filter positioned slightly downward ao as to minimize duat falling d.ireetly onto the filter. Sampling was conducted for the entire duration of the mixing opera tions but because of the higher anticipated concentrations associ ated with sanding of the joint compounds It was decided to change filters approximately every ten minutes. Sampling during the sand ing on the various joint compounds was conducted over e total period of sixty minutes. Therefore six consecutive ten-minute samples were obtained for each sanding test. In addition to the ten-minute tests, samples were collected over thirty-minute periods as well, i.e.,two consecutive. 30-mlnute samples for each sandirfg test. After collec tion of each sample the filter cap was replaced and the cassette, or sampler heed, wee seeled immediately and prepared for transfer to the analytical laboratory. The method of counting asbestos fibers vae essentially the same as 'that used by the U.S. Public Health Service for the enumerat ion. of asbestos dust on membrane filter:. The description of this method first appeared in an article written b y C . H . Edwards and J.R. Lynch nd appeared in the Annals of Occupation! Hygiene. Volume 2, pages 6 (1968). . % - 4 4 * In lUBBiry, the method coneieted of the folloving itepi. - PLAINTIFF'S ( exhibit I M f21C5) A pie-shaped section of each sample vas mounted on a standard microscope slide using a high viscosity solution of membrane filter in a 1:1 mixture of diethyl oxalate and dimethyl phthalate to render the filter transparent* The asbestos fibers which were on the surface of the filter were then counted using s 10X eyepiece and a 4OX objective with phase contrast illumina tion. A number of fields, selected at random across the sample, suf ficient to reveal a minimum of 100 fibers were examined and fibers greater chan five micrometers in length were counted. Any particle having an aspect ratio of three or greater vas con sidered to be a fiber. Although it was conceivable that there would be fibers of paper or other materials present on the fil ters vhleh would have been dislodged from the vallboard during the sanding operation it did not appear that these were of any adverse consequence during the analysis of the samples. Although ' it is realized that the counting technique is not specific in terms of being able to identify the chemical nature of the fibers present in the sample, all of Che fibers observed in these sam- . pies appeared to have physical features characteristic of asbes tos fibers. For those samples collected over a thirty-minute period, and vhleh were too heavily loaded to evaluate directly under the microscope, the collected material on the filters vas dislodged * in a highly purified distilled water bath using an ultrasonic unit (Dynasonlc Corporation, Model C6 generator and Model T6 tank) and diluted to one liter. An aliquot of the resulting suspension vas drawn, passed through a membrane filter (Mllllpore Type BA ) and vas then `analysed according to the procedure described above. PRESENTATION OF RESULTS A total of four joint compound products were used during this study. These products (two dry mix and two "ready mix") were supplied by two manufacturers whose id-entities were not known to the investiga tor. The products were identified by code (2D, 2R, 4D and 4 R ) , a number referring to the supplier and the letter indicating whether the product vas a "dry" or "ready-mix" compound. The results of the sampling program conducted during the mixing of the two dry mix products and sanding tests on all four Joint com pounds are presented in Tables I through ZV. Examination-of these data reveals the folloving: 1. During mixing of Joint*Compound 2D, the worker vas exposed to a concentration of -31 .A. fibers, greater than five micro meters in length, per eusie centimeter of air. 2. The amount of total particulate generated during the/aanding operation on Joint Compound 2D vas so great that direct _3 - [ EXHIBIT I I tte z n iti I analysis of the ten-minute sam p l e e v a ^ n o c possible. Anelysis of the thlrty-minute samples, vhlch were redeposited, indicated sn average concentration of 39.4 fibers, greater than five micrometers In length,per cubic centimeter of air. 3. The results of analyzing four of the six ten-minute samples collected during sanding on Joint Compound ZB. indicated an average concentration of 4.2 fibers per cubic centimeter; two of the samples were too heavily loaded to analyze di rectly. Results of analysis of the two thirty-minute'sam ples collected during the sanding on Joint Compound 2R indi cated an average concentration of 11.1*fibers per cubic cen timeter, a factor of over 2.5 times as high as the average obtained from analysis of the ten-minute samples. 4. The sample obtained during the mixing of Joint Compound 4D indicated a concentration of 7.6 fibers, greater than five micrometers in length, per cubic centimeter of air. 5. Results of analyzing four of the alx ten-minute samples col lected during the sanding on Joint Compound 4D Indicated an average concentration of 4.4 fibers per cubic centimeter. Analysis of the two thirty-minute samples, which were sub- jetted to the redepositing procedure, indicated an average concentration of 14.8 fibers per cubic centimeter, a factor of 3.4 times as high as results obtained fron the ten-minute * samples. 5. The results of analysis of five of the six samples obtained during the sanding on Joint Compound 4R indicated an aver age concentration of 10.8 fibers per cubic centimeter. Re sults of analysis of the two thirty-minute samples indicated an average concentration of 9.7 fibers per cubic centimeter, a value essentially the same as that obtained from analysis of the ten-minute samples. . S i x of the thirteen ten-minute samples obtained during sand ing on the four Joint compounds indicated concentrations in excess of five fibers per cuble centimeter. Both mljclng operations generated asbestos concentrations in excess of five fibers per cuble centimeter. . :Two of the thirteen ten-minute samples collected during the sanding tests indicated concentrations in excess of ten fibers per cubic centimeter, the acceptable celling concen tration. One of the two mixing operations generated an as bestos -in-air concentration in excess of ten fibers per cubic centimeter. Of the four produets tested, sanding on 2R and 40 resulted in concentrations less than, but approaching, the current acceptable limit for continuous exposure of workers, five fibers per cubic centimeter. Product 4R consistently pro duced 'very high concentrations of total dust which obscured the asbestos fibers on the samples. 6 PLAINTIFF'S EXHIBIT /17/JZ1 CONCLUSIONS The following eoneluiloni re presented on the basis of observations and measurements made during Che study reported herein. 1. Based on the results of the ten-minute samples, it is appar ent that the exposures of workers engaged in mixing and sand ing of the various Joint compounds used during this test would be to concentrations approaching or exceeding five fibers, greater than five micrometer* In length, per cubic centimeter of air. 2. It is clear that persons engaged In the aiming and sanding of joint compounds similar to those used during this test would be exposed to concentrations of airborne asbestos in excess of ,tvo fibers per cubic centimeter during the entire eourse of their work. This value is the proposed acceptable limit for an eight-hour time-weighted average exposure to asbestos which is scheduled to become effective July 1, 1976. 3. With the exception of the tests conducted during sanding on joint compound 4R the results of analysis of the thirty-min ute samples, .using the redeposition technique, were consist ently higher than those obtained by direet analysis of the ten-minute-samples by a factor of 2-1/2 to 3-1/2. Therefore, it appears that use of the redeposltlon technique would re sult in the apparent concentrations of asbestos in air being higher than actually present >and would therefore err on the "conservative" side. 4. Discounting the results obtained by analyals of the thirty minute samples, for which the redeposltlon technique was used, three of the samples collected (mixing of 2D and sand ing on 4R) indicated concentrations in excess of ten fibers per cubic centimeter and are therefore -a concern as peak exposures. Vith those exceptions, the problea is one of con trolling the time-weighted average exposures of workers .to asbestos. In that respeet, it must be pointed out that the sampling results reported herein are indicative of the expo.sures of workers during the mixing or sanding operations and not their time-weighted average exposure for a full workday. RECOMMENDATIONS 1. The results of sampling reported herein should be analysed in conjunction vith a study of the work practices and routine of persons engaged in mixing, sanding or otherwise being exposed, to Joint compounds similar to chose used in this study. In this way a true evaluation of the 'tlme-welght-ed average exposure of such workers to asbestos csn be made. If it Is true that, as reported by workers used during* this test, it would be unlikely for an individual to mix or sane on the Joint compounds for greater than two hours per workday, then the time-weighted'aver age exposure of such workers to asbestos likely would be within acceptable limits. Of course, the problem of controlling any 7 exposures to belov ten fibers per cubic centimeter would still hsve to be contended with. 2. Proa the standpoint of being able to eliminate or minimise the __ problem of excessive concentrations of asbestos being generated by handling and use of the joint compounds, consideration should be given to the following aspects. a. The most effective means of eliminating the asbestos prob lem obviously would be to eliminate asbeseos from the Joint compound formulations if this is feasible.. Although the spe cific role chat asbestos plays in the Joint compound formu lations is not clear it is understood that manufacturers of Joint compounds consider it necessary that asbestos be in the formulations. b. Prom an engineering standpoint, it may be necessary to imple ment the following measures in conjunction with mixing and sanding of the joint compounds containing asbestos. i. Mixing of the joint compounds could be done in such a way that the material is more effectively vetted as it is removed from the containers or could be done within an enclosure, with or without mechanical ventilation, so as to minimize the amount of asbestos fibers released into the breathing zone of the workers. 11. Although the resules of the air sampling reported herein indicate concentrations of asbestos fibers in excess of acceptable limits, either those currently enforced or those proposed to be made effective in July, 1976, It was obvious during the .study that the sanding process in general has associated with it exposure of the worker to tremendously high concentrations of total dust. There fore, if means were Implemented to maintain the exposure of the workers to total psrtleulate to within acceptable limits there would be an inherent control of the asbestos problem as well. Although more extensive in nature, en gineering control of the total dust generated by the sand ing operations is feasible. Such control techniques would include, but not be limited to, the uie of a vet sanding technique and/or use of a portable local exhaust ventila tion system incorporating, as the air moving device, a unit similar to common industrial vacuum cleaners and bag collectors. The next phase of the testing program to control workers' expo* . sures to asbestos during use of.she Joint cement compounds logi cally vould be evaluations of the various potential engineering' control concepts indicated or inferred above. Robert S. Soule, ?.. Vice-President, Industrial Hygiene Services Client Gypsum Association I GEORGE D. CLAYTON & ASSOCIATES INDUSTRIAL HYGIENE SAHPL1HG SUMMARY Material 1973 JOINT COMPOUND 2D l Semple . ' () Date No. Description 11/19 2D-H 11/19 2.D-S-1 11/19 2D-S-2 11/19 2D-S-3 11/19 2D-S-4 Hlxlng of compound^) Sending on compound^6) (c \ Sanding on compound' 9 Sanding 'on compound^6^ Sanding on compound'6) Sampling Period Start Stop s 09:28 09:34 11:57 12:27 11:57 12:07 Sample Height 1 Sample I Volume 1*Liters 1 U | 60 1 m Concentrat ton Fibers 1 . >5pm/cc 31.4 35.2** * 12:07 12:17 1 * 12:17 12:27 1 m * 11/19 2D-S-5 Sanding on compound(c) 41/19 2D-3-6 Sanding on. compound (c) 9 _ 11/19 2D-S-7 Sanding on compound^6-) 11/19 2D-S-8 1__________________ Sanding' on compound C6) 12:27 12:57 12:27 12:37 12:37 12:47 12:47 12:57 1 60 1 . . I 43.6** * * -- r-'-i-- * All samples vers obtained In the breathing cone of the workers. Mixing of Compound 2D vas done.by Mr. Harold McDowell in King's Mill Townhouse Unit U-81. * Sanding of Compound 2D was done by Mr. James Paaquarlello In King's Mill Townhouse Unit U-77. Psychrometric conditions in U-77 at ll;4S were 56*P dry bulb, 4l*P vet bulb (221 relative humidity) too heavily loaded for direct analysis material on filter was taken Into suspension and an aliquot redeposited for analyssi's Citent Cypeua Aaaoclatlon UbUAOc. u. t U Y l 'UH A ASSOCIATES INDUSTRIAL HYCIEUE SAMPLING SUMHARX Material Aabeatoe 1973 Date 11/19 Staple. No. ! 2R-S-1 JOINT COMPOUND 2R Deacrlptlon ^ ^ Sanding compound 0) Sampling Period I s t a r t I Stop Sample [weight iSampla I Volume Concentration Fibera Lltera >5|im/cc 15:48 16:18 SO 12.3*< 11/19 2R-S-2 Sanding ^compound i*1) 15:48115:58 20 4. S 11/19 2R-S-3 Sanding compound^) 15:58 16:08 20 4.2 11/19 2R-S-4 Sanding compound n o 16:08116:18 20 4.1 11/19 2R-S-5 Sanding compound 16:18 16:48 60 9.9** 11/19 2R-S-6 Sanding compound 16:18 16:28 20 11/19 11/19 2R-S-7 2R-S-8 Sanding compound^) Sanding compound 0) 16:28 16:38 16:38 16:48 20 3.8 20 (a) All aaaplaa vara obtained in thin breathing cone of the workers.' (b) Sanding of Compound 2R'was done by Mr. David Potter In King's Mill Townhouaa Unit U-79. Paychrometrlc conditions*ln U->9 at 15:45 were 39*P dry bulb, 35*F wat bulb (66X relative humidity). * too heavily loaded for direct analyala ** material on filter waa taken into auapenalon and an aliquot redepoalted for analyala lr*il * * ..... Cilene Cypaua Aaaoclation CEOHCB D. CLAYTON A ASSOCIATES INDUSTRIAL HYGIENE SAMPLING SUMHAEX Material .Aabeatoa 1973 Data Staple No. JOINT COMPOUND 40 Description ^ Sampling [Sample Period_____|llelght Start Stop I Staple | Volume ! Lltere Concentration Tibera >Siia/cc 11/19 4D-H Mixing coapound(k) 09:09 09:17 U.4 7.6 11/19 4D-S-1 Sandlng compound (c) 10:20 10: SO 60.0 IS.5** 11/19 4D-S-2 Sanding compound(c) 10:20 10:29 IS.O 5.2 \1/19 4D-S-3 Sanding compound U ) 10:29 10:40 22.0 11/19 4D-S-4 Sanding compound(*) 10:40 10: SO 20.0 3.7 11/19 4D-S-5 Sanding compound 10:50 11:00 20.0 4.1 11/19 11/19 4D-S-6 4D-S-7 Sanding compound^) Sanding compound (c) 10:50 11:20 11:00 11:10 60.0 20.0 14.1** 11/19 4D-S-8 Sanding comppund(c) 11:10 11: 20 20.0 4.7 (*) All aamplce were obtained in the breathing cone of the vorkere. lb) Hlxlng o Compound 40 wee done by Mr. Harold McDowell In Klng'p Mill Townhouee Unit U-80. , * (c) Sanding of Compound 4D wee done by Mr. Jamee Paaquarlello in King'e Mill Townhouee^ Unit U-76. Paychrometrlc conditlone (dry and wet bulb teapera- turea) were not recorded. * too heavily loaded for direct analytic ** notarial on filter waa taken into auapenalon end.an aliquot redepoaltad for anelyala * . . . . .. . ! i. . j * , Client 1973 )itc Cypsuo Association INDUSTRIAL HYCIEHE SAMPLIUC SUHMART MatetUl Asbestos Sample No. JOINT COHPOUND 4R Daacrlptlon ^ Sampling Period Sample Height Start Stop Siapl Concentration Volume I piker* Liter* l>5pm/ee 11/19 4R-S-1 11/19 4R-S-2 11/19 I 4R-S-3 11/19 4R-S-4 11/19 I 4R-S-5 11/19 4R-S-6 11/19 I *R-S-7 11/19 I4R-S-8 Sanding compound(b) Sanding compound(b) Sanding coaoound (b) Sanding compound^) Sanding compound (b) Sanding compound Sanding compound Sanding coapound(b) 14:31 15:01 14:31 14:41 14:41 14:51 14:51 15:01 15:0 15:31 15:0 1 S : M 15:1 VOID 15:18 15:31 60.0 20.0 20.0 20.0 60.0 20.0 JLLlI a* 6.3 7.5 19.9 8.1** 5.3 26.0 I 15.0 All oamploa vara obtalnad .In the breathing cone of the worker* Sanding of Compound 4Rva* done by Hr. David Potter. In King'* Hill Tounhousa Unit U-7B. Psychroyetrlc condition*'In U-78 at 14:45 war* 44#P dry bulb, 38*F wet bulb (68X relative humidity). materiel on filter was taken Into suspension and an aliquot redaposltad for analysis 4 TT