Document Yrn2Xmy3dvZwrNrO9XwRMOMLk

FILE NAME Kaiser Gypsum KG DA 197T 3 NoE v 19 DOC KG101 DOCUMENT DESCRIPTION Report - Evaluation of Exposure to Asbestos During Mixing and Sanding of JointCompounds GEORGE D. CLAYTON & ASSOCIATES ENVIRONMENTAL CONTROL SPECIALISTS SOUTHFIELD MICHIGAN 48075 EVALUATION OF EXPOSURE TO ASBESTOS DURING MIXING AND SANDING OF JOINT COMPOUNDS GYPSUM ASSOCIATION Denver Colorado November 19 1973 GP032 1 96 EVALUATION OF EXPOSURE TO ASBESTOS DURING MIXING AND SANDING OF JOINT COMPOUNDS GYPSUM ASSOCIATION Denver Colorado INTRODUCTION The Gypsum conduct an Association Stained George D. industrial hygiene survey at a Clayton and Associates to test site located in Den- ver Colorado centrations of The purpose of the survey airborne asbestos to which was to determine the workers were exposed con- dur- ing mixing results in and sanding of joint cement compounds and to interpret the terms of potential health hazards with particular refer ence to regulations promulgated Safety and Health Act of 1970. 19 1973 by Mr. Robert D. Soule under authority of the Occupational This study was conducted -- --November of Clayton and Associates Results of that study are reported herein BACKGROUND The Gypsum Association located Illinois is & trade association at 1603 Orrington Avenue in Evansto which represents ten to fifteen in dustrial companies which are engaged in the manufacture of products incorporating gypsum or gypsum 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 Metallic Mine Safety Act and the Occupa tional Safety and Health Act Technical committees composed of ber- sonnel from companie comprising the Gypsum Association have been es tablished with particular interest in the occupational safety and health field Of particular concern in this respect was the poten- tial hazard associated with exposu 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 comp manufacturing and supplying the joint compound vary is all of them incorporate asbestos in the understood that product whether essentially as a dry.com dry.com pound or a ready product In order to evaluate the exposure of workers to asbestos during han- dling and use of the decided to undertake joint compound a test program products the Gypsum during which several Association products would be mixed and sanded George D. tained to collect and analyze samples Clayton and which would Associates was rerepresent the ex- posure of workers November 19 1973 Townhouses which engaged in the study The tests were performed on in a development of townhouses known as King's Mill were under construction in a suburban area north of Denver Colorado POTENTIAL WITH HEALTH HAZARD ASSOCIATED EXPOSURE TO ASBESTOS Asbestos is a generic term referring to various mineral silicates The types used most widely in industrial applications include chrysotile OF white asbestos a hydrated magnesium silicate site or grey asbestos an iron magnesium silicate crocidolite or blue asbestos a sodium iron silicate tremolite a calcium mag- nesium silicate and anthophyllite another iron magnesium sili- cate Of these chrysotile accounts for over 90 percent of the total usage of asbestos in this Country with amosite 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 estos is that of inhala- tion of airbor fibers resulting in a type of pneumoconiosis Referred to as asbestosis Small asbestos fibers can 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 inhal 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 ratory insufficiencies or even cardiac failure It has been determined through toxicological and epidemiological studies that long fibers 20 to 50 micrometers in length are most active in the production of the fibrosis Fibers shorter than about two micrometers in length are practically without an irritating effect There is some evidence that other minerals having fibrous teristics can produce simi lar reactions Many recent studies have indicated an tion between exp 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 ction with asbes tos in all cases of this disease there is a strong correlation e tween exposure to crocidolite and Occurrence of mesotheliomas Other types ever of asbestos have been this new hazard has implicated to received much a much public lesser extent How- attention because it has been suggested that very minimal occupational expos can be sufficient to produce the disease in some individuals For many years the American Conference of Governmental Industrial Hygienists has recommended a threshold limit value TLV of five miilion particles per cubic foot of air mppcf for all types of asbesbearing dusts containing less than one percent alline silica The threshold limit value is efined as the concentration of an air borne contaminant to which it is believed that nearly all workers can be exposed for continuous and epeated work days without experienc adverse effects The TLV of five appof was based on the impinger sam- pling technique which Was selected as the standard method in the ly epidemiological studies of occupational exposure to asbestos * this method air is drawn through an impinger containing water and the total particles both grains and fibers in an aliquot of the sample counted using field microscopic techniques Within recent years because of the increasing concern about asbes in the environment and the resulting need for a more relevant sam- pling method the American Conference of Governmental IndustriIandustlrial Hygienists has proposed a TLV of five fibers greater than five mic meters in length per cubic centimeter of air This standard is based based on the membrane filter technique with actual microscopic fiber count- ing at 400-450x magnification using phase contrast illumination The Occupational lished the above Safety and Health Administration OSHA has estab concentration five fibers greater than five micro- meters in length per cubic centimeter of air as an emergency stand ard and have announced that effective July 1 1976 the acceptable limit for an eight weighted average exposure will be re- duced to two fibers In addition OSHA has established the con centration of ten fibers greater than five micrometers in length per cubic centimeter Workers shall not be of air a an accept ceiling concentration exposed to rations of asbestos in excess of this value regardless of duration of exposure SAMPLING AND ANALYTICAL METHODS The air sampling conducted to evaluate exposures of Workers to asbes- tos was all of the breathing zone type These samples were col- lected by drawing air through mm diameter membrane filters Milli pore Type AA at operated a rate of about two liters per minute using small 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 fastened on the outside of the worker's shirt at approximate breathing zone height Thus these samples were repre sentative of the weighted average conditions to which the ---- -- were exposed during the sampling period The sampling head consisted of a three piece cassette Millipore during sampling the face cap was removed and the filter was used in an open face mode with the filter positioned slightly downward so as to minimize dust fall directly onto the filter Sampling was conducted for the entire duration of the mixing oper 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 a total perio of sixty minutes Therefore six consecutive minute samples were obtained for each sanding test In addition to the minute test les were collected over minute periods as well e two consecutive minute samples for each sanding test After collec tion of each sample the filter cap was replaced and the casset ---- sampler head was sealed immediately and prepared for transfer to the analytical laboratory The method of counting asbestos fibers was essentially the same as that used by the U.S. Public Health Service for the enumeration of asbestos dust on membrane filters The description of this method 6P032 first appeared in an article written by G.H. Edwards and J.R. and appeared in the Annals of Occupational Hygiene Volume 2 1-6 1968 Lynch pages 19 In summary the method consisted of the following ste A shaped section of each sample was mounted on a standard microscope slide using a high viscosity solution of membrane filter in a 1 mixture of diethyl oxalate and dimethyl phtha- late to render the filter transparent The asbestos Fibers which were on the surface of the filter were then counted usin a 10X eyepiece and a 40X objective with phase contrast illumina- tion A number of fields ficient to reveal a selected at random across the sample suf- minimum of 100 fibers were examined and fibers greater than five micrometers in length were counted Any particle having an aspect ratio of three or greater was con sidered to be a fiber Although it was conceivable that there would be fibers of paper or other materials present -- --the fil ters which would have been dislodged from the wallboard 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 ---- --,of --the fibers present in the sample all of the fibers observed in these sam- ples appeared tos fibers to have physical features characteristic of asbes- For those samples collected over a minute period and which were too heavily loaded to evaluate directly under the microscope the collected material on the filters was dislodged in a highly purified distilled water bath using an ultrasonic unit Dynasonic Corporation Model G6 generator and Model 16 tank and diluted to one liter An aliquot of the resulting suspension was drawn passed through a membrane filter Millipore Type HA and was then analyzed according to the cecure described above PRESENTATION OF RESULTS A total of four joint compound products were used during this study These products two dry two manufacturers whose mix and two ready mix were supplied by identities were not known to the investiga- tor The products were number referring to the identified by code 2D supplier and the letter 2R 4D and indicating 4R a whether the product was a dry or ready compound The results of the sampling program conducted the two dry mix products and sanding tests on pounds are presented in Tables I through IV data reveals following during the mixing of all four joint Com Examination of these 1 During mixing of Joint Compound 2D the worker was exposed to a concentration of 31.4 fibers greater than five cicremeters in length per cubic centimeter of air sand- 2 The amount of total particulate generated during the sand- ing operation on Joint Compound 2D was so great that e analysis of the minute samples was not possible Anal- ysis of the minute samples which were redeposited indicated an average concentration of 39.4 fibers greater than five micrometers in lengtph er cubic timeter f air The results of analyzing four of the six minute samples collected during sanding on Joint Compound 2R 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 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 minute samples 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 Results of analyzing four of the six minute sample collected during the sanding on Joint Compound 4D indicated an average concentration of 4.4 fibers per cubic centimeter Analysis of the two minute samples which were subjected to the redepositing procedure indicated an average concentration of 14 fibers Per cubic centimeter a factor of 3 times as high as results obtained from the minute samples 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 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 minute samples Six of the thirteen minute samples obtained during sand- ing on excess the four joint of five fibers compounds per cubic indicated concentrations in centimeter Both mixing operations generated asbestos concentrations in excess of five fibers per cubic centimeter Two of the thirteen minute samples collected during the sanding tests indicated concentrations in excess of ten fibers per cubic centimeter the acceptable ceiling concen tration One bestos of the two mixing operations generated an concentration in excess of ten fibers per as cubic centimeter Of the four products tested sanding on 2R and 4D 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- GPO32 duced very high ntrations of total the asbestos fibers on the samples dust which obscured 1701 CONCLUSIONS The and following conclusions are presented on the basis of measurements made during the study reported herein observations 1 Based on the results of the 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 micrometers in length per cubic centimeter of air : 2 It is clear that persons engaged in the mixing and anding of joint compounds similar to those used during this test would be exposed to concentrations of airborne asbestos in excess of two fibers per cubic centimeter during the entire Course of their work This value is the proposed acceptable limit for an eight 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 ute samples using the redeposition technique were consist- ently higher than those obtained by direct analysis of the minute samples by a factor of 2-1 to 3-1 Therefore it appears that use of the redeposition 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 analysis of the thirty- minute samples for which the redeposition 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 thereforea concern as exposures With those exceptions the problem is -- peak ----of con- trolling the weighted average exposures of workers to asbestos In that respect it must be pointed out that the sampling results reported herein are indicative of the exposures of Workers during the mixing or sanding operations and not their weighted average exposure for a full workday RECOMMENDATIONS 1 The results of sampling reported herein should be analyzed i conjunction with a study of the work practices and routine of persons engaged in mixing sanding or otherwise being exposed to joint compounds similar to those used in this study In way a true evaluation of the weighted average exposure this of such workers to asbestos can be made If it is true that as reported by workers used for an individual to mix during this test it or sand on the joint would be unlikely compounds for greater than two hours per workday then the weighted ave age exposure of such Workers to asbestos likely would be wi acceptable limits Of course the problem of controlling any exposures to below ten fibers have to be contended with per cubic centimeter would still 2 From the standpoint of being able to eliminate or minimize 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 asbestos from the joint compound formulations if this is feasible Although the specific role that asbestos plays in the joint compound formu lations is not clear it is unders that manufacturers of joint compounds consider it ary that asbestos be in the formulations b From 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 1 Mixing of the joint compounds could be done in such a way that the material is more effectively wetted as it is removed from the containers 10 could be done within an 0 enclosure with or as to minimize the without mechanical amount of asbestos ventilation fibers released into the breathing zone of the workers ~ 11. Although indicate the results of concentrations the air sampling reported herein 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 particulate to within accepta 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 technique and be limited to the use ofa wet use of a portable local exhaust sanding ventila- tion system incorporating as the air moving device a unit similar to common industrial vacuum cleaners and bag collectors 3 The next phase of the testing program to control workers expo sures to asbestos during use of the joint cement compounds logi cally would be evaluations of the various potential engineering control concepts indicated or inferred above This report prepared by rae) / aon ! . ads. GP032 Robert D. Soule P.E. President Industrial Hygiene Services 1203 Client Gypaum Association TABLE I GEORGE D. CLAYTON & ASSOCIATES INDUSTRIAL HYGIENE SAMPLING SUMMARY Material GP03 1204 AsbestoB 1973 Date Sample JOINT COMPOUND 2D a Description 19 | 2D Mixing of compounbd 11/19 2D Sanding on compouncd 19 2D | Sanding on compouncd 11/19 2D | Sanding on compouncd 11/19 2D | Sanding on compouncd 19 J 2D Sanding on compound c 11/19 2D | Sanding on compouncd 19 2D Sanding on compound c 19 2D | Sanding on compouncd Sampling Period Sample Weight Start | Stop Sample Concentration Volume / Fibers Liters ...m 09:28 11:57 12:07 12:17 | + 12:27 12:57 12:37 13 31.4 60 35.2 - * - * - * 60 43.6 ** - * 12:37 12:47 12:57 - * - * a All samples were obtained in the breathing zone of the workers b Mixing of Compound 2D was done by Mr. Harold McDowell in King's Mill Townhouse Unit 81 . . c Sanding of Compound 2D was done by Mr. James Pasquariello in King's Mill Townhouse Unit 77 Psychrometric conditions in 77 at 11:45 were 56 dry bulb 41 wet bulb 22 relative humidity too heavily loaded for direct analysiu material on filter was taken into suspension and an aliquot redeposited for analysistaken TABLE II Client _ 1973 Date Gypaum Association GEORGE D. CLAYTON & ASSOCIATES INDUSTRIAL HYGIENE SAMPLING SUMMARY Material GP032 1205 Asbesto8 Sample JOINT COMPOUND R a Description Sampling Period Sample Weight Start | Stop Sample Volume Concentration Fibers Liters 5 m 19 | 2R | Sanding compounbd 19 2R | Sanding compounbd 1/19 | 2R Sanding b compound 11/19 2R | Sanding compounbd 11/19 2R | Sanding compounbd 11/19 2R | Sanding compounbd 11/19 | 2R Sanding compound b 11/19 | 2R | Sanding compounbd 16:18 15:58 15:58 16:18 16:48 16:28 16:38 16:48 60 20 20 . 20 60 20 20 20 12.3 ** 4.5 4.2 4.1 9.9 * 3.8 * a All samples were obtained in the breathing zone of the workers in b Sanding of Compound 2R was done by Mr. David Potter in King's Mill Townhouse Unit 79 Psychrometric conditions 79 at 15:45 were 39 dry bulb 35 wet bulb 66 relative humidity * too heavily loaded for direct analysis ** material on filter W88 taken into auspension and an aliquot redeposited for analysis Client _ 1973 Date Gypsum Association TABLE III GEORGE D.'CLAYTON & ASSOCIATES INDUSTRIAl hygiene SAMPLING SUMMARY Material GP03 1206 Asbesto8 8ample JOINT COMPOUND 4D a Discription Sampling Sample Period = Weight Start | Stop Sample Volume Concentration Fibers Liters ...m 11/19 | 4D Mixing compound b 11/19 | 4D | Sanding compouncd 19 | 4D | Sanding compouncd 11/19 | 4D Sanding compound c 11/19 | 4D | Sanding compouncd 11/19 | 4D | Sanding compouncd 1/19 | 4D Sanding compound c 11/19 | 4D Sanding compound c 11/19 | 4D | Sanding compouncd 09:09 09:17 10:20 10:50 10:20 10:29 10:29 10:40 10:40 10:50 _ | 10:50 11:00 10:50 11:20 11:00 11:00 11:10 11:10 11:20 14 4 7.6 60.0 15.5 18.0 5.2 22.0 * 20.0 3.7 20.0 60.0 20.0 4.1 14. * 20.0 4.7 m All samples were obtained in the breathing zone of the workers b Mixing of Compound 4D was done by Mr. Harold McDowell in King's Mill Townhouse Unit 80 ; c Sanding of Compound 4D was done by Mr. James Pasquariello in King's Mill Townhouse Unit 76 Psychrometric conditions dry and wet bulb tempera tures were not recorded * too heavily loaded for direct analysis ** material on filter Waa taken into suspension and an aliquot redeposited for analysis Client [ 1973 Date Gypsum Association TABLE IV GEORGE D. CLAYTON & ASSOCIATES INDUSTRIAL HYGIENE SAMPLING SUMMARY Material GP032 1207 Asbestos Sample JOINT COMPOUND 4R Description Sampling Sample Sample Period Weight | Volume Concentration Fibers Start | Stop Liters 5...m 11/19 | 4R Sanding compounbd 11/19 | 4R | Sanding compounbd 11/19 | 4R | Sanding compounbd 11/19 | 4R | Sanding compounbd 19 | 4R | Sanding compounbd 1/19 | 4R | Sanding compounbd 11/19 | 4R | Sanding compounbd 11/19 4R Sanding compounbd 14:31 15:01 14:31 14:41 14:41 14:51 14:51 15:01 15:01 15:31 15:01 15:11 15:11 VOID 15:18 15:31 60.0 20.0 11.3 ** 6.3 20.0 7.5 20.0 19.9 60.0 8.1 ** 20.0 5.3 - - 26.0 15.0 a All samples were obtained in the breathing zone of the workers b Sanding of Compound 4R was done by Mr. David Potter in Townhouse Unit 78 King's Mill 44 Psychrometric conditions'in 78 at 14:45 were dry bulb 38 wet bulb 68 relative humidity material ae on filter was taken into suspension and an aliquot redeposited for analysis