Document MGQJKpq0e695gQN5aDzmN3xZM

FILE NAME: Drywall Spackling Compounds (DWSC) DATE: 1977 July 12 DOC#: DWSC031 DOCUMENT DESCRIPTION: Internal Report - Union Carbide - Airborne Fiber Counts in a Consumer Spackling and Drywall Replacement Installation Project AIRBORNE FIBER COUNTS i n A CONSUMER SPACKLING and DRYWALL REPLACEMENT INSTALLATION PROJECT Date Sampled: June 21-25, 1977 Date Reported: July 12, 1977 Samples Collected By: H. B. Rhodes Union Carbide Corporation Samples Analyzed By: G. J. Spencer Union Carbide Corporation Reported By: H. B. Rhodes Union Carbide Corporation Union Carbide Corporation Metals Division Niagara Falls, New York SUMMARY AND CONCLUSIONS Residual asbestos exposure in a two-story residential structure that resulted from two prior consumer uses of asbestos-containing tape-joint compound was measured. Asbestos exposure during and after a consumer spackling and drywall renovation job was also measured. This job consisted of extensive spackling in one room and removal and replacement of approximately three 4' x 8' panels of drywall. Samples were collected on Millipore filters and counted by optical phase-contrast microscopy in accordance with the March 30, 1977 edition of the NI0SH-0SHA method (P & CAM 239). The absence of significant numbers of short and/or narrow fibers not visible optically in the samples was verified by scanning electron microscope techniques at magnifications of 1 ,500X and to a limited extent at 15,000X. The results showed that residual asbestos exposure was somewhat less than 0.01 fibers/cc >5y and was not changed appreciably by the present test. It is questionable whether this is really different from the natural background. The combined spackling and drywall renovation operation tested gave a maximum, one-day time-weighted average operator exposure of about 0.3 fibers/ cc longer than 5y and a maximum ceiling exposure (10 minutes) of 0.5 fibers/cc >5y. Considering the size of the area renovated, these values are consistent with values of 1 - 4 fibers/cc >5y that have been reported for commercial sand ing operations where entire series of rooms (including the ceilings) are sanded in sequence. General area household samples during the operations ranged from 0.007 to 0.3 fibers/cc >5y and averaged 0.05 fibers/cc >5y. TABLE OF CONTENTS Section OBJECTIVES TEST LOCATION AND GENERAL PROCEDURE RENOVATION OPERATIONS AND SAMPLE COLLECTION Residual Asbestos Level (6/21/77) Preparation and First Application of Compound(6/22/77) Spackling Drywall Removal and Replacement Second Application of Compound (6/23/77) Sanding of Second Application and Installation of Finish Coat (6/24/77) Sanding of Finish Coat (6/25/77) FIBER COUNTING PROCEDURE NIOSH-OSHA Optical Phase-Contrast Method Scanning Electron Microscope Examination PRESENTATION AND DISCUSSION OF RESULTS Residual Level (6/21/77) Preparation and First Application of Compound(6/22/77) Second Application of Compound (6/23/77) Sanding of Compound and Application of FinishCoat (6/24) Sanding of Finish Coat Summary of Results During Renovation Operations CONCLUSIONS APPENDIX Operations Log Page 1 1 2 2 2 2 3 3 4 4 6 7 7 8 9 9 10 11 12 25 No. 1 2 3 (a) & (b) 5 6 7 8 LIST OF FIGURES Title Sample Locations - Prior to Testing Preparation - Spackling and Drywall Installation Installation of Spackling and Drywall Package Information - Drywall Compound Finished Spackling and Drywall Chrysotile, Possible Amphibole, and Non-Asbestos "Fibers" - Phase Contrast Illumination, 400X Scanning Electron Microscope Analysis on Mi 11ipore Fil ter Airborne Fiber During Drywall Removal and Wet-Out of Compound - Phase Contrast Illumination, 400X Paqe 13 14 15 16 & 17 18 19 20 & 21 22 LIST OF TABLES No. Title I Summary of Airborne "Fiber" Concentrations - Consumer Spackling and Drywall Installation II Airborne "Fiber" Concentrations by Location and Operation During Consumer Spackling and Drywall Renovation Operations Page 23 24 OBJECTIVES This study had the following objectives: 1. To measure a residual household exposure to asbestos resulting from consumer use of asbestos-containing spackling compound, tape-joint compound, and the installation and presence of a fireplace log with attached asbestos. 2. To measure asbestos exposure durinq a consumer spackling and a drywall removal and replacement operation. TEST LOCATION AND GENERAL PROCEDURE The tests were run at a two story, brick-veneer dwelling located in Snyder, New York. The house was built in 1939 with all interior walls finished with plaster on perforated wallboard. Two substantial consumer uses of asbestos had occurred in subsequent years which could be the source of residual exposure. In 1968 the owner finished a recreation room in the basemert about 18 feet long and 11 feet wide using drywall on three sides. A dry-mix taping compound was used but the specific product could not be identified. The present tests confirm that it contained asbestos, but the exact amount was not measured. Vinyl-asbestos tile was used on the floor of this room and the ceiling was finished with cellulosic tile. A gas log with asbestos clued on to simulate ashes was also installed at this time. In 1975 an upstairs bathroom was completely renovated. Extensive repairs were made on the ceiling using several coats of an asbestos-containing taping compound manufactured by Georgia-Pacific. Considerable sanding was done on an area of about 50 square feet. In addition, three sheets of 1/4" x 4' x 8' asbestos-cement sheet were hand sawed and power drilled for the tub enclosure. The present renovation work covered two operations, spackling and drywall removal and replacement. The work was done at widely separated loca tions, i.e., 2nd floor and basement, over a five-day sequence as outlined below. These steps follow the installation procedure recommended by the manufacturer of the compound. Specific operating details will be described in connection with the sample collection. 1. Measurement of "background" or-residual asbestos level in the house. 2. Preparation of cracks for spackling. Removal of old drywall and hanging of new board. Wet-out of asbestos-containing drymix tape joint compound. Application of first coat of compound (including burying of joint tape). Clean up. 3. Application of second coat of compound. 4. Sanding of second coat of compound and application of third coat. Clean up. 5. Sanding of third coat and clean up. -2- The consumer doing this work was reasonably skilled in small to medium home repair jobs of various types, but had no special skills in handicraft or woodworking. Prior experience with drywall was limited to the installation of the recreation room described previously. The work was done in a manner that was considered to be reasonably representative of "middle-of-the-road" consumer use. No specific precautions were taken to avoid dust but deliberate efforts to cause airborne dust were not made. RENOVATION PROCEDURE AND SAMPLE COLLECTION Residual Asbestos Level (6/21/77) Samples to estimate the residual fiber level in the house and to serve as a reference point were collected in the upstairs bedroom (to be spackled), in the cellar recreation room (to be renovated with new drywall), in the first floor living room (to represent a general living area), and out-of-doors (to give an indication of background). Sample locations are shown in Figure 1. All samples, here and throughout the tests, were collected on Mill!pore membrane filters of 0.8y priority with battery-powered M.S.A. pumps calibrated to a flow of two liters per minute. Preparation and First Application of Compound (6/22/77) Spackling: The preparation for this operation is illustrated in Figures 2 (a) and (b). The room, ~ 1 1 ' x 18', had three cracks about 18' long running from the lower corners of two windows to the baseboard. Shifting of an entire ceiling section had left a large crack ~ 3 ' long in the ceiling below the corner. There were also about 6' of smaller cracksadjacent to this plus an area about 8" x 8" that needed to be filled in to a depth of about 1/8" to conform to the ceiling contours. The cracks were cleaned out with a chisel to remove loose material and to give enough space to fill. The dust and debris produced were swept up with a pan and brush and deposited in a paper trash bag. Later in the day, drywall compound was applied to the cracks and ceiling with a 3" putty knife. A total width of about 3" along the cracks was covered. An area air sample was collected over the entire day at the location shown in Figure 2 (a). A composite personal sample on the operator was also collected for the entire day, (except for the wet-out of the compound, which was sampled separately) and included this preparation, clean-up and application. An all-day area sample was collected simultaneously in the first floor living room at the location shown in Figure 1 (b). Drywall Removal and Replacement: The drywall replacement involved one wall, ^11' long, of a cellar recreation room. The old drywall was first torn out as illustrated in Figure 2 (d). This was accomplished by breaking enough of the board with a hammer to allow access with a pry bar. It was observed during the operation that the tape adhered strongly to the boards and could be pulled off in long sections. There was little or no observed tendency for the joint material to come off the board or powder. The large pieces of drywall were carried outside. The smaller pieces and other dust and debris were swept up with a pan and brush and deposited in the trash barrel shown. -3- Three pieces of new 3/8" gypsum board were next fitted and nailed to the studding. Where needed, cuts were made by scoring the front of the board, cracking, and cutting the backing paper with a razor blade. These cuts were made out-of-doors to facilitate moving the pieces into the house. After the handling of the board was completed, a five-pound box of dry-mix tape-joint compound was mixed in a bucket as shown in Figures 3 (a) and (b). The powder was gradually added to the prescribed amount of water with vigorous mixing, allowed to stand, and re-mixed with the viscosity adjusted via additional water in accordance with the manufacturer's instruc tions. The overall operation took about 17 minutes. Separate operator and area samples were taken during this step. The entire box was mixed at one time and was stored with a reasonably tight cover when not in use for the duration of the job. The product used was Durabond Wall board Compound, Ready-to-mix Powder, manufactured by the United States Gypsum Company which was purchased on June 19, 1977. The logo on the box is reproduced in Figures 4 (a) and (b). Note the asbestos warning label and the application directions which have been followed carefully in this test. It should be noted that this box printing has a 1974 copyright and was the last one on the shelf with the asbestos warning label. More recent products from this manufacturer appear to be asbestos free. After wet-out, the and a first coat was applied coat was also applied to the knife. compound was used to implant and cover the tape to the nail-heads. A 6" knife was used. A first cracks in the upstairs bedroom with a 3" wide In addition to the separate samples during the wet-out, an area sample was taken for the entire day at the location shown in Figure 2 (c). Second Application of Compound (6/23/77) A second application of compound was made in both rooms on the following day. This took a total of one hour and 15 minutes. No visible dust was generated and no air samples were taken. Sanding of Second Application and Installation of Finish Coat (6/24/77) When dry, the second coat of compound was hand sanded in both rooms using 150 grit paper attached to a block. This operation is illustrated in Figures 3 (c) and (d). After each sanding step was completed, the dust was swept up with a pan and brush and deposited in a trash bag in the same manner as after the preparation step described previously. Personal and area air samples were collected during the combined sanding and clean up step for each room. Following sanding, a finish (3rd) coat of compound was applied to the cracks and the drywall. Area samples were taken to cover this time and the remainder of the day. A full-day sample, including the sanding periods, was taken in the first-floor living room. -4- Sanding of Finish Coat (6/25/77) The final (second) sanding and clean up and the sample collection pattern for this operation closely duplicated the one just described. The finished work is shown in Figure 5. In addition to the renovation work de scribed, the clothes worn during the test sequence were unfolded and placed in a washing machine in normal fashion. This included shaking out the material held in the cuffs of the pants. A personal sample was taken during this time period. FIBER COUNTING PROCEDURE NIOSH-OSHA Optical Phase-Contrast Method The latest draft of the NIOSH procedure, P & CAM #239 dated March 30, 1977 was used as the general basis for optical counting. This version of the method differs significantly from earlier editions in that: 1. Substantial changes have been made in the selection rule covering which fibers encountered by the reticle are to be included in the count. This largely eliminates systematic bias due to fiber size distribution. 2. The total coefficient of variation is expressed as a function of the total number of fibers counted instead of a single value applicable to all situations. A minimum count of 10 fibers is also required. These are clearly substantial improvements but the method still has some serious shortcomings particularly when applied to situations where airborne fiber concentrations are low and/or where non-asbestos particulate material is present.0 ) Both of these situations exist in the present study and certain refinements in the procedure have been necessary in order to present the results in the most understandable and meaningful fashion. It should be emphasized that these are additions to the procedure and are not believed to be in conflict with it. The legal basis for refinements to be described is found in the following quotation from P & CAM 239: "3. Interferences In an atmosphere known to contain asbestos, all particulates with a length to diameter ratio of 3 to 1 or greater, and a length greater than 5p should, in the absence of other information, be considered as asbestos fibers and counted as such." [Emphasis added.) (1) See for example, "A Report on the Fiber Content of Eighty Industrial Talc Samples Obtained From, and Using the Procedures of, the Occupational Safety and Health Administration. MBS, May 1977." This report is one of-the principle reasons for an international conference on the problem sponsored by MBS and scheduled for July 18-20, 1977. The approach here emphasizes the development and use of "other infor mation" to obtain the most intelligent assessment of what is seen through the microscope. In this connection it is important to realize that optical fiber counting is not an exact science but an art. It requires a unique blend of tal ent, training, and concentration. An experienced counter develops both in "eye" and a counting rhythm, which permits him to recognize "fibers", decide which fibers are of the appropriate type and dimensions to be counted, and to move rapidly from field-to-field so the counts do not take an inordinate amount of time. The objective is to provide the experienced operator with a set of ground rules to judge between the various types of fiber and put them in certain classes. Under phase-contrast illumination, chrysotile asbestos has some very distinctive characteristics. It is typically dark appearing, composed of random-size bundles and flexible hair-like threads with curvature. When chryso tile fibers are short, however, i.e., 5-10y, perfectly straight, dar< rod-like particles occur. Classical chrysotile fibers are illustrated in Figures 6 (a) and (b). Fibers of amphibole asbestos are usually larger in diameter than chrysotile and more rigid and rod-like in appearance. They can, however, break down into very fine needle-like material. With the exception of crocidolite, the amphiboles also can contain prismatic crystals which usually have the appearance of chips. The amphiboles normally refract light differently than chrysotile under phase contrast and appear brighter. As particle size decreases, however, light refraction and contrast are diminshed and the particle will appear darker and less definitive. At this size it cannot be distinguished from chrysotile fibers of similar dimensions. Figure 6 (c) illustrates material which is probably amphibole. It is not well defined in the photograph, but the rod-like particles have a narrow bright band along the center axis which shifts as the focus is changed. Unfor tunately, there are a number of non-amphibole particles which show the same features. Examples include, but are certainly not limited to certain mineral wool fibers, chips of fiberglass generated by abrasion, wollastonite, and fibrous talc. In addition to the three kinds of "fiber" just described, i.e., chrysotile, amphibole fibers and chips, and material that looks like the amphiboles, particles are frequently encountered that meet the NIOSH fiber defin ition of L/D >3y, L >5u but are obviously not asbestos in any form. These include such things as fiberglass "poles", some clay and mica particles, organic fibers, and linear agglomerates of non-fibrous material. The bright "wavy" particles in Fiber 6 (d) illustrate this type of material. On the basis of the optical characteristics discussed tempered with broad operator experience with a wide variety of known particulate materials, fiber counts at this laboratory are made and reported in the categories de scribed below. Material w hich is^ obviously not asbestos is not counted even though it meets the L/D = 3, L >5u criteria. 1. Chrysotile asbestos - Any fiber having an aspect ratio >_3 and a length >_5y that is, in the operator's judgement, chrysotile. In -ti the event of doubt, any_ fiber h\vinq the proper dimensions and dark appearance will be included as chrysotile. On this basis the short, dark amphibole fibers, where present, would be reported as chrysotile. 2. Possible amphibole - Any fiber of the appropriate dimensions that is not judged to be chrysotile and is not obviously material other than asbestos. This would include all amphi boles and materials similar in appearance. It is evident that this classification is oriented towards a more reliable assessment of the airborne level of chrysotile asbestos. It does not address the problem of identifying amphiboles or distinguishing them from sim ilar appearing non-asbestos materials. We believe it provides significant added information in situations where chrysotile is of prdominent interest and have used it in the counting of the filters collected in this test. For tape-joint compounds chrysotile is an important ingredient, any "possible am phibole" originates as impurities in other mineral ingredients. The other counting problem encountered relates to the very low air borne asbestos concentrations found in most of the samples. The NIOSH procedure sets an optimum fiber density on the filter of 50 to 100 fibers per 100 viewing fields and states a minimum density of 10 fibers/100 fields. Within these limits the method is claimed to be applicable to a concentration range of 0.1 to 60 fibers/cc with a total coefficient of variation of 0.26 - 0.4. The validity of these claims, particularly with regard to accuracy, is a subject of considerable controversy at this time. The discussion of this question is well beyond the scope of this study. For the present work, sample times were adjusted, within the limits set by the nature of the operation, to deposit the proper density of fiber on the filter. Where this was not possible, additional fields were counted in increments of 100 fields, until the minimum of 10 fibers was achieved. Separate results for chrysotile and possible amphibole are reported at values rounded to one significant figure. Fibers/100 fields and the total number of fields counted are also shown in all cases to provide more complete information. Scanning Electron Microscope Examination The application of electron microscope techniques to samples collected on Mi 11ipore filters is complicated by the fibrous nature of the filter. The most widely used technique at present involves the deposition of a carbon film on the surface of the filter to fix the particles in place, placement of the filter with the carbon side down on a grid, and a slow dissolution of the filter with vapor. This is a tedious process and unless a very careful technique is used, some loss of fibers occurs. Union Carbide is working on a much simpler approach where a controlled exposure to vapor collapses and consolidates the filter surface so "it is rela tively smooth without dissolving it to the point where the fibers sink out of sight. The treated filter can then be carbon or gold coated and individual fibers identified by electron diffraction analysis for chemical constituents. The method is admittedly less versatile for identification than transmission techniques, but is also very much faster. It is illustrated in Figure 7 where 7 (a) is the untreated filter, 7 (b) is the treated filter, gold coated and 7 (c) is a representative "Edax" pattern for chrysotile asbestos. Magnification here is 2000X. Samples were prepared by this technique from 6 mm2 segments from samples M-30, M-28, M-36, N-79, and N-72. These were scanned randomly at 1500X. Samples M-30 and M-28 were checked systematically for 50 viewing fields of 0.0048 mm2 area each. Sample M-30 was also scanned at 15,OOOX. Asbestos fibers were found to be extremely rare and it was clear that within the limits of resolution set by the magnifications used there was not a multi plicity of short or narrow fibers that were missed by phase contrast optical methods. Quantitative measurements on these samples are in progress. PRESENTATION AND DISCUSSION OF RESULTS A detailed listing of all samples taken including location, operation tested, collection time, and the counting results is provided in Table I. These airborne fiber concentrations are summarized by work location and the kind of operation being conducted in Table II to provide an overall picture of the results that is easy to visualize. Each day's operation will be discussed in detail in this section. Residual Level (6/21/77) "Blank" samples were taken before and after the test. These samples were removed from the carrying case, set aside unopened, and then counted in the same manner as the other samples. The number of fibers found in 500 fields is compared with the results for the two samples collected out-of-doors in the following table: Sample Identification Fibers >5u Found in 500 F ields Chrysoti1e Possible Amphibole Blank M-21 3 1 H-81 4 0 Outdoor Samples M-32 9.5 5.5 N-97 3 2 Fibcrs/cc >Eu Chrysoti1e Possible Amphibole -- - 0.003 0.0004 0.002 0.0002 In general, the blank samples run about 1 fiber in 100 fields and the outdoor samples ranged from about the same to three times higher. Since most of the samples collected during the testing had filter loadings substan tially above 1 fiber/field no corrections were made for the blank. Indoor samples were taken in three rooms in the house before the start of the work and after it was completed and cleaned up. The results are shown and are also compared with the outdoor samples in the following table: -8- Airborne Fiber Concentrations^ Before and After Renovation Sample Location Before Renovation Chrysotile Possible Amphibole After Renovation Chrysotile Possible Amphibole Bedroom (2nd Floor) Living Room (1st Floor) Rec. Room (Cellar) OutIIdoors 0.009 0.01 0.006 0.003 - 0.001 0.0 0.002 0.002 - 0.007 0.006 _0.002 0.0004 0.001 0.001 0.001 0.0002 (1) A H results expressed as fibers/cc longer than 5y. Total fiber concentrations in the house were all 0.01 fiber/cc or less (range 0.003-0.01) and averaged 0.008 fiber/cc. The renovation work did not appear to cause any increase. Considering the uncertainties in the analy tical method it is questionable whether these levels were actually different from the natural background. In any case, neither the prior consumer work with asbestos-containing materials nor the present renovation represent a significant source of continued asbestos exposure in this house. Preparation and First Application of Compound (6/22/77) On this day the wall cracks were cleaned out and opened up with a chisel, the old drywall was ripped out and replaced, the dry-mix compound was wet-out, the drywall tape was buried and a first coat of spackling was applied. Both working areas were also cleaned up before the compound was applied. Area samples were collected throughout the day in each of the three rooms. A com posite personal sample was obtained on the operator over the same time period. Separate area (cellar only) and personal samples were obtained for the wet-out of the compound. The fiber concentrations found are summarized in the following table: Airborne Fiber ConcentrationsN y During Preparation and First Application of Compound Sample Location Chrysotile Possible Amphibole Bedroom (Spackling) Living Room (No work) Rec. Room (Drywall) General construction Wet-out of compound 0.02 0.02 0.3 0.03 0.08 0.009 0.007 0.04 :rator + (2) General construction' 0.2 0.0 Wet-out of compound 0.1 0.2 (1) All results expressed as fibers/cc longer than 5y. (Z) Covers both bedroom and recreation room. -9- The main sources of airborne fiber were the rip-out of the old drywall and the wet-out of the dry-mix. Total fiber concentrations in the operator's breathing zone of about 0.3 fibers/cc were reached in both of these operations. The area samples show that preparation for spackling raised the level in the bedroom from ^0.01 to ~0.1 while the living room, where no work was done, went from 0.001 to 0.03 and the drywall tear out in the cellar gave 0.03. Since all of these samples, both personal and area, were collected for nearly eight hours, the results can be considered as represent ing of eight-hour time-weighted averages. The types of fiber found are shown in Figure 8. Both chrysotile and possible amphibole are illustrated. Second Application of Compound (6/23/77) This was a wet operation with no visible dust. Air samples were not collected. Sanding of Compound and Application of Finish Coat (6/24/77) This operation covered sanding the dry compound in both rooms where it had been applied, clean-up after sanding, and application of the second coat of compound. Personal and area samples were collected during sanding in each room. Day-long area samples were taken after sanding in all three rooms. The results are shown in the following table: Airborne Fiber Concentrations :d During Sanding of Coir,pound and Application of Finish Coat Sample Location Duri ng Sanding Possible Chrysoti1e Amphibole After Sandi ng Possible Chrysoti1e Amphibole Bedroom (Spackling) Area Samples Personal Samples Living Room (No work) Area Sample Ree. Room (Drywall) Area Samples Personal Samples 0.2 0.07 0.1 0.09 0.0 0.07 < ---------------- 0.02/0 .0 -- ---------- > 0.2 0.08 0.03 0.02 0.01 0.004 (1) All results expressed as fibers/cc longer than 5u. The total fiber concentrations during the actual sanding operation were in the 0.1 - 0.3 fiber/cc range which is similar to the tear-out operation of the previous day. The sanding and clean-up operations only lasted 93 minutes These concentrations, therefore, represent maximum or ceiling values that would be combined with 387 minutes of zero exposure to calculate an 8-hr. timeweighted average since the operator left the house after completion of sanding. -10- Thus: TWA = l i ) ( 0 , l O + ( 7 3 ) 1 0 , 1 ) . J ,, ( .3 8 7 ) ( 9 1 . 0 02 f 1 b e r ; , /cc >5p After sanding the levels dropped sharply to the range of 0.01 to 0.1. TWA values calculated from the results of this sample and past sample that cover a total period of nearly eight hours were 0.08, 0.02 and 0.02 fibers/cc >5p for the bedroom, living room and cellar, respectively. Sanding of Finish Coat (6/25/77) The last day's operation consisted of the sanding of the final coat of tape-joint compound, clean up with a pan and brush, and replacement of furniture. Area and personal samples were taken at the same locations and in the same manner as the previous day. Results are summarized as follows: Airborne Asbestos Concentrations^^ ^ During and After Sanding of Finish Coat Sample Location Bedroom (Spackling) Area Samples Personal Samples During !Sandi no Possible Chrysotile Amphibole 0.02 0.09 0.02 0.0 After Sanding Possible Chrysotile Amphibole 0.007 - 0.001 - Living Room (No work) Area Sample Rec. Room (Drywall) Area Samples Personal Samples / 0.07 0.03 a nnn /n n m 0.01 0.008 0.002, 0.5(2) / 0.001 0.03 (1) All results expressed as fibers/cc longer than 5p. (2) During shake out of clothes and placing in washing machine. The sanding here was less intense than the previous day and the maximum fiber count for the operator was about 0.1 fiber/cc with an 13-hr. TWA of 0.005. (Operator again not present for remainder of the day.) After the clean-upjthe levels in all three rooms were back to the less than 0.01 fiber/cc level that had been observed prior to the tests. Overall TWA values for the total period sampled were 0.009, 0.007 and 0.01 fibers/cc >5y. The highest level found throughout the test sequence, 0.5 fibers/cc, occurred as a short (10 minute) ceiling sample while the work clothes were placed in the washing machine. In this operation four shirts were ooened up, the pockets were checked and the shirts were dropped into the washing machine. The pants cuffs were shaken into a trash bag and the pants were also dropped into the machine. The corresponding 8-hour TWA for this operator was 0.02 fibers/cc based on exposure to an average level of (0.008 + 0.007 + 0.003)/3 = 0.006 for the remainder of the day. Summary of Results During Renovation Operations The TWA values so far described for the various operations are summarized below: Personal #1 n Preparation, Instal 1ation & Clean up CeilinqO) TWA (^ 0.3 Sanding & Clean up Ceilinq TWA Sanding & Clean up Cei1inq TWA 0.3 & 0.1 0.02 0.09 & 0.04 0.5 0.005 0.02 Area Spackling 0.1 0.3 No operations - 0.03 - Drywall renovation - 0.3 0.2 (1) All results expressed as fibers/cc >5u. 0.08 0.02 0.02 0.04 - 0.08 0.009 0.007 0.01 The highest ceiling exposure for the operator was 0.5 fibers/cc >5y and the highest full-day time-weighted average was 0.3 fibers/cc >5p. For the three days where asbestos dust generating operations were in progress the TWA in the three rooms monitored ranged from 0.007 to 0.3 fibers/cc >5p and averaged 0.06 fibers/cc >5p. It is also relevant to point out here that the concentrations found are in reasonable accord with values of 1-4 fibers/cc reportedO) for commercial sanding operations where a series of rooms are sanded in succession. Using a value of 0.2 fibers/cc >5p for one wall, four walls might be expected to result in a level around 1 fiber/cc >5u. A ceiling, where the dust drops downward instead of tending to flow down the wall could double this to 2 fibers/cc >5p. Allowing for variations in asbestos content in the compound, application and sanding techniques, ventilation, etc. the test results appear quite reasonable. \ It should also be pointed out that substantial consumer uses of drywall compound occurred in this residence three times in nine years. When it is considered that such uses take place only when substantial repairs are made or for such things as finishing a basement, attic, or adding a room it is suggested that this frequency is considerably higher than average. A rate of something like once in ten years is suggested as more typical. (1) "Asbestos and Silica Dust in the Drywall Industry", H. B. Rhodes and B. L. Ingalls, GDCI Drywall, Jan./Feb. 1976, pp. 8 -12- CONCLUSIONS Recognizing that there may be some serious limitations on the reliability of the analytical procedure, the data, as obtained, support the following conclusions: 1. The three, fairly substantial consumer uses of asbestoscontaining taping compound at this residence have resulted in a residual asbestos exposure of somewhat less than 0.01 fibers/cc longer than 5y. It is questionable whether this is different from the natural background. 2. The combined spackling and drywall renovation operation tested gave a maximum, one-day time-weighted average operator exposure of about 0.3 fibers/cc longer than 5y and a maximum ceiling exposure (10 minutes) of 0.5 fibers/cc >5y. Considerin the size of the area renovated these values are consistent with values of 1-4 fibers/cc >5u that have been reported for commercial sanding operations where entire residences and apartments (including the ceiling) are sanded. 3. The values found are substantially below the current 0SHA proposal of 5 fibers/cc ceiling and 0.5 fibers/cc TWA and the NI0SH proposal of 0.5 and 0.1 fibers/cc for daily occupational exposure for a full working lifetime. SAMPLE LOCATIONS - PRIOR TO TESTING 1 (a) Upstairs bedroom. Cracks to be patched are under the window(s) and in the ceiling above the window. 1 (b) 1st floor living: room, 1 (c) Cellar recreation room. Wall to be replaced. 1 (d) Outdoor sample. Figure 1. PREPARATION-SPACKLING AND DRYWALL INSTALLATION -14- 2 (c) Sample location for drywall replacement. 2 (d) Removal of old drywall. Figure 2. INSTALLATION OF SPACKLING AND DRYWALL -15- 3 (c) Operator hand sanding spackling. 3 (d) Operator hand sanding drywal1. F'gure 3. For treating Joints In Interior gypsum panels. Drying-type formulation for do-it-yourself application NET WT. 5 LBS. U*. IM Roady-to-mix powder 7 DURABOND WALLBOA This all-purpose com pound is designed for embedding tape, finishing joints and concealing nailheads in gypsum panel walls and ceilings Also used to produce a light texture prior to painting. This is a drying-type compound and should not be mixed with chemically hardening-type materials. DIRECTIONS FOR USE MIXING: Mix compound in a clean container, using 3 to 3 '/2 pints lap water to 5 lbs. compound. Sift powder compound into water while stirring. Mix vigorously for about 3 m in .,o r u n til powder is thoro ughly wet.Allow to soa kafew minutes,then re-m ixto a smooth consistency. Adjust mix if necessary after second stirring by adding small amounts of water or com pound. Additional water is required when compound is to be used as a texturing material. Mixture is then ready for use or may be held (or several days. Do not intermix with other materials. APPLICATION: Drive in nails, leaving dimple in surf ace pa per of gypsum panels, to receive DURABOND Compound. Butter com pound into channel formed by tape red edges of pane Is, filling fully and evenly. Center tape and force down into fresh compound. Leave sufficient compound under tape lo r proper bond. Remove excess. As soon as tape is embedded, cover with thin layer of compound. Apply first covering coat oI compound over all nailheads. After first coat is completely dry, apply second coat, feathering edges about 2 in. beyond channel edges. Second-coat nailheads. After second coat is dry, sand lightly. Apply a thin finishing coat to joints and nailheads. Feather joint edges an inch or two beyond second coat. Sand lightly when dry. For texturing, use brush, roller or trowel for desired texture effect. May be painted when completely dry. During cold-weatherapplication, provide heat to maintain 55CF. min. temperature. CAUTION." Contains asbestos fibers. Avoid creating dust. Breathing asbestos dust may cause serious bodily harm. KEEP OUT OF THE REACH OF CHILDREN Pcf w irrin t/. disclaimer ind notice red ulrementj. read Current U S O. Instruction) and specifications. ccpiaj ol which are tree on request. CM c00. Illinois 6C606 T-j'4-L'SC: nc- `-'r P roduced tn U S A. c ION. Ud ll "jiSu-h 17Figure 4 (b) 10FINI SUED SPACKLING AND DRYWALL 4 (c) Finished ceiling cracks. 4 (d) Finished drywall installation. Figure 5. -19- CIIKYSOTILE, POSSIBLE AMPHIBOLE , NON-ASBESTOS (Phase Contrast Illumination, 400X) FIBERS" 6 (a) Chrysotile Asbestos (M-22) 6 (b) Chrysotile Asbestos (M-22) 6 (c) Possible Amphibole (B-27) --H I-1- 6 (d) Possible amphibole and non asbestos "fibers" (B-27) Figure 6 SCANNING ELECTRON MICROSCOPE ANALYSIS ON Mli i.IPORE' FILTER ' (SOOUX) ~ '20~ 7 (b) Treated Filter Figure 7 - 21Figure 7 AIRBORNE FIBERS DURING DRYWALL REMOVAL AND' WET-QllT OF COMPOUND (Phase Contrast Illumination 400X) 8 (a) Drywall Removal (M-24) 8 (b) Wet-out of Tape Joint Compound (M-30) -H Y*~ V' Figure 8 to i in T'W n r " totOtotom -s"gn-- SUMMARY QF AJF.SC_Pi.F_> ` 2 1 ^ _C0'. : v CONSUMER SPACKLING AND Z l t ^ K i ;*,,**_ t- Minutes 489 492 480 505 Description of Operation Outdoors- about 4 ' in air. See figure i (d). - Bedroom-^4' off floor, 3 1/2' from side wall, 9' from end wall. See F igure 1 (a ). Living room- ^ 4 ' off floor, 3 1/2' from side wall. See Figure 1 (b). Recreation room - Center about 4 ' off floor. See Figure 1 (c). o Uo"> No. of Fields Counted 500 200 200 300 . N o . of F i1ter Section Used 2 2 1 1 2 *----- ----- . } 0.6 6.5 8.5 4.8 429 Personal sample. Opera tor preparing 100 crocks for spackling. Removing old drywoll. Cleanup after three opera tions. Installation of drywall. Spackling and taping with "wet" compound. (Taping in same area as TJC wet out.) 17 Personal sample. Operator wettinq out 200 dry tape joint compound. 422 Bedroom- 8 ' from side wall. See 100 Figure 2 (a). During preparation, cleanup, and spackling. 140 Living room - Same location as M-37. 100 During various activities on other floors as noted. 100 Cellar- 4 ' from side wall. 12' from 100 wall replaced. 4' from floor. See Figure 2 (b). Ouring drywall removal. 70 Cellar- Same location as M-36. During 200 wet out of TJC and immediately following. -INISH COAT (6/24/77) 20 Personal sample. Operator sanding 200 spackling. Upstairs bedroom. Clean up after sanding. 20 Bedroom - During sanding and cleanup. 200 Same location as M-28. 148 Bedroom - After sanding and cleanup. 100 Sane location as M-28. 164 Living room - Ouring and after sanding 100 . and cleanup of spackling and application of finish co ot. 71 -Ml .. -1" . ' '> '1 l f 1 1 141 1 3.5 1 14.0 1 11.0 1 167.5 1 3.0 1 3.25 1 6.0 1 0.0 ' 1 12.5 9 - -23- k r M W --T-l-t-x r * ---- .0 0 3 Concentrations Possible A.rphibo1e " F ib e r " " f i b e r s / 100 f i e l d s F i b e r /cc .i 0.002 0.009 0.2 1.25 0.001 0.01 0.0 0.006 0.6 0.0 0.001 * 02 0.0 0.0 0.1 0.02 0.02 0.3 o:o3 0 .1 0.2 0.0 0.02 5.0 4 .5 6 4 4 2.5 2 47.5 0 0.2 0.08 0.009 0.007 0 .0 4 0.09 0.07 0 .0 7 0.0 Consents Too heavily loaded to count acc-'a1 Better than 1/6 of field obscured : particulate. Particulate in 5u -amay not be chrysotile. Loaded with small particulate fibers s h o r t b u t w i t h i n 5y r a n g e . Sorce e r i dence of asbestos. Geometric chunky raterial preseHl. ro<J-shaped with l i g h t refractiva i 422 2 Cctiroon- fl9 <jre 3' fro U S U ) . (Turing . 1 1 . 1* pr p. r 1 1, 109 cleanup, nd ip.ckling. 440 living room - location M-J7. During various 4Ct1vit)Cl CO 100 Moors as noted. l < 0 0 Cellar- 4 ` from side will. 12* fro 100 will 'ey 1jeed. 4* from floor, See ri^jre (0 ). Our 1 0 9 drywdll re*rvl. 70 Cellar- Sa*"* location as M-36. During 200 wet out of TJC and immediately following r n r s H COAt (6/24/77) 20 Personal sample. Operator sanding 200 spackling. Upstairs bedroom. Clean up after sanding. 20 Bedroom - During sanding and cleanup. 2C0 Same location as M-28. 448 Bedroom - After sanding and cleanup. 100 Same location as M-28. 464 living room - During and after sanding 100 and cleanup of spackling and application of finish coat. 73 Personal sample. During sanding of 100 dVyrfVi 1 in' cellar. Cleanup after sanding. Application of finish coat. 15 Cellar - during sanding and cleanup. 300 Same location as M-36. 421 Cellar - after sanding and cleanup. 200 Same location as M-36. 14 Personal sample. Operator sanding 500 z spackling. Upstairs bedroom. Cleanup after sanding. 16 Rodrnom - during sanding and cleanup. 500 > Same location as M-28. 421 Bedroom - after sanding and cleanup. 300 2 Same location as M-28. 2 465 Living room - During and after second 300 sanding and cleanup. 33 Personal sample. Operator sanding 500 2 TJC In cellar. Cleanup after sanding. 34 Cellar - During sanding and cleanup. 300 1 Same location as M-36. 326 Cellar - After sanding and cleanup. 500 2 Same location as M-36. 10 Personal sample. Handling of work 200 1 clothes after sanding. Other clothes sorted during 2 and added to washing machine most of period. (Operator if ) " 500 2 1025 Outdoor s.irple. Some location 500 2 as M-32. 1.9 0.5 4.6 4.3 1.3 3.5 1.0 6.75 0.8 0.6 M* r Mf 007 0.006 0.03 0.07 0.002 0.5 - 0 0.5 0.6 1.0 0.4 0.06 0.6 0 0.0 0.4 0.08 0.009 0.007 0.04 0.09 0.07 0.07 0.0 0.08 0.03 0.004 . O.o 0.02 0.001 0.001 0.008 0.01 0.001 0.03 - s loaded with snail particulate filers, short but within 5u range. S o TM evi dence of asbestos. Geometric chunky material preserit. rod-shaped with light refractivd inc TABLE II AIRBORNE "FIBER" C O N C E N T R A T I O N S ^ BY LOCATION AND OPERATION DURING CONSUMER SPACKLING AND DRYWALL RENOVATION OPRATIONS -24- ResidualBefore Tests 6/21/77 pnd-Floor Bedroom (Spackling) Area Samples Personal Samples st-Floor Living Room (No repair work. General exposure.) Area Samples ament Recreation Room (Drywall removal and replacement.) Area Samples Personal samples ioors Area Samples 0.009/0.001^ - 0.01/0.0 0.006/0.001 - 0.003/0.002 Preparation of Job & First Installation of Compound _________ 6/22/77_________ Preparation, Wet-out Clean up, of (5) Application Compound Second A p p i ication of Compound 6/23/77 Sanding of Compound Application of Finish Coat __________ 6/24/77_____________ During Sanding After Sanding('15)` During Sanding of Finish Coat 6/25/77 Sanding After Sand 0.02/0.08 - - - No samples taken. 0.2/0.07 0.1/0.09 0.0/0.07 - 0.02/0.02 0.09/0.0 0.007/0.00 - 0.02/0.009 - " ^------- 0.02/0.0 --------- ) <---- -- 0.006/0.001 --------- 7 0.3/0.007 0.03/0.04 " 0.2/0.0^ 0.1/0.2 0.2/0.03 0.08/0.02 0.01/0.004 - 0.07/0.01 0.03/0.008 0 . 0 0 2 / 0 . CGI 0.5/0.03^ 0.0004/0.0002 All results expressed as fibers/cubic centimeter lonyer than 5 micrometers. The first number given refers to chrysotile asbestos, the second to "possible amphibole", i.e., 0.009 fibers/cc >5p of chrysotile and 0.001 fibers/cc >5u of possible amphibole. See Section for discussion of these fiber categories. Also includes spackling preparation, clean up, and application of compound. During shake out of work clothes and placing in washing machine. These are short time period or ceiling samples. APPENDIX -2b- Operations Log 6/21/77 Sampling for ^ hours in bedroom, living room, and cellar. 6/22/77 9:30 a.m. - 10:05 a.m. 10:05 a.m. - 11:45 a.m. Preparation of wall and ceiling cracks in bedroom. Including clean up. Removal of cellar drywa11. 11:45 a.m. - 12:00 Noon 12:00 Noon - 12:30 p.m. 12:30 p.m. - 3:38 p.m. 3:38 p.m. - 3:55 p.m. Clean up after drywall removal. Lunch (Pump running.) Fitting and nailing of drywall. Wet-out of drywall compound. 4:00 p.m. - 4:20 p.m. Spackling upstairs bedroom. 4:20 p.m. - 5:40 p.m. Fill cracks in wallboard. Apply tape, cover. Fill nail holes and corner joints. 6/23/77 7:45 a.m. 9:00 a.m. Apply second coat to cracks and to wal1board. 6/24/77 7:10 a.m. - 7:30 a.m. 7:37 a.m. - 8:12 a.m. 8:12 a.m. - 8:53 a.m. 8:58 a.m. - 9:10 a.m. Sanding and clean up of spackling in bedroom. Sanding and clean up of drywall in cellar. Finish coat of mud applied to drywall. Finish coat of mud applied to spackling in bedroom. 6/25/77 12:40 p.m. 12:55 p.m. 1:03 p.m. - 1:37 p.m. 1:55 p.m. 2:05 p.m. Final sanding and clean up of spackli ng. Final sanding and clean up of wal1board. Clothes in washer. Job complete.