Document 5D23kGGQO8QjyYp6k7anVLarD

-x\K. Am. lnd. Hyg. Assoc. J. 44(6):42X-4.12 (I9K.1) Worker Exposure to Asbestos During Removal of Sprayed Material and Renovation Activity in Buildings Containing Sprayed Material NAM WON PAIK. RICHARD J. WAl.COTTand PATRICIA A. BROGAN Clayton Environmental Consultants. Inc.. Southfield. Ml 4X075 Contents and types of asbestos in fireproofing insulation materials sprayed on ceilings of 127 buildings throughout the U.S. were studied. Asbestos was found 1o be present in more than 50% of the buildings and chrysotiie was the main component identified. Frequency distribution of airborne fiber concentrations was lognormal. During renovation activities by various workers, including sheet-metal workers, carpenters and electricians, average Tiber concentrations at workers' breathing zones were less than 2 fibers/cc. but exceeded 0.1 fibers/cc. During removal of sprayed materials, workers were exposed to extremely high concentrations (average 16.4 fibers/cc) when dry methods were used. When wet methods were used during removal, the airborne fiber concentrations were sharply reduced to less than 2 fibers/cc. Introduction In 1970. more than half of all multistory buildings con structed in the U.S. contained sprayed inorganic fibers as a fireproofing agent. The material usually contains 5 to 35% asbestos fibers, mineral wools, clay binders, adhesives, syn thetic resins, and other proprietary agents such as oils.1" In 1973. the U.S. Environmental Protection Agency (EPA)1"1 Kanned the spray application of fireproofing material con ning more than 1% asbestos by weight because occupa tional hazards associated with inhalation of asbestos fibers had been well established. Howev er, material already sprayed within the structures still remains a potential source of expo sure to asbestos fibers. Complete removal of the sprayed material from the structures is a permanent control method for eliminating asbestos exposures. Workers are heavilyexposed to asbestos when they remove sprayed fireproofing materials without using wetting agents. Workers such as carpenters, electricians and duct workers are also frequentlyexposed to airborne asbestos fibers when they perform ren ovation or maintenance within buildings containing sprayed fireproofing material. This paper presents the results of bulk TABLE I Type and Content of Asbestos in Fireproofing Material Sprayed in 11 Buildings Investigated Building Type of Asbestos Asbestos Content Identified (% by Weight) A (Illinois) B (Kansas) C (Wisconsin) D (Texas) E (Oklahoma) F (New York) G (Arizona) H (Georgia) 1 (Florida) J (Tennesseel K (New York) Chrysotiie Chrysotiie Amosite Chrysotiie Chrysotiie Chrysotiie Chrysotiie Chrysotiie Chrysotiie Chrysotiie Chrysotiie 4 6 2 4 6 2-15 10- 12 B- 9 6- 8 8 3 sample analyses and investigations of worker exposures to airborne asbestos during renovation activities and removal of sprayed material. Scope and Methods This study was conducted from February 18. 1980 to December 8.' 1981 to determine worker exposures to air borne asbestos fibers during both renovation activity and removal of sprayed materials. Eleven multistory buildings located in variouscilies of the U.S. were investigated during renovation activities and three buildings were surveyed while the sprayed materials were being removed. Bulk sam ples were collected from sprayed fireproofing materials to identify the types of asbestos and to determine asbestos content in the materials. X-ray diffraction using a Norelco Type 120-102-20 X-ray diffractometer was employed for the analyses of bulk samples. Airborne asbestos fiber concentra tions were measured at the workers' breathing zones using the method specified by both the Occupational Safety and Health Administration (OSH A)13'and the National Institute for Occupational Safety and Health (NIOSH).1'" Samples were collected by draw ing air at measured flow rates (nomi- TABLE II Results of Analysis of Bulk Samples from 127 Buildings in the U.S. Results Number of Buildings Asbestos Content (%) Amosite identified 2 2- 6 Chrysotiie identified 64 2-35 Both amosite and chrysotiie identified 2 2 - 3 (amosite) 4 - 5 (chrysotiie) No asbestos found 59 - Total 127 Copyright 1983. American Industrial Hygiene Association 428 Am. lnd. Hyg. Assoc. J {44) June. 1983 TABLE III Distribution of Airborne Asbestos Fiber Concentrations by Job Titles _____________During Renovation Activity in Office Buildings Job Title <0.05 Number of Samples by Fiber Concentrations (Fiber$/cc) 0.05 0.11 0.21 0.31 0.41 0.51 0.10 0.20 0.30 0.40 0.50 1.0 1.1 2.0 Carpenter 21 25 22 9 8 7 7 1 Electrician 5 11 75 1 2 - 1 Sheet-metal ' 10 10 5 2 3 2 2 worker Painter 2 3 11 - - - >2.0 5 3 3 - Total 28 49 40 20 1 1 12 9 4 11 Total Number of Samples 105 35 37 7 184 Removal Method Dry Wet Total TABLE IV Distribution of Airborne Asbestos Fiber Concentrations by Removal Methods During Removal of Sprayed Fireproofing Material in Office Buildings <01 0.1 0.5 Number of Samples by Fiber Concentrations (Fibers/cc) 0.61.0 1.1 2.0 2.1 11.0 21.0 31.0 41.0 51.0 10.0 20.0 30.0 40.0 50.0 100.0 101.0 200.0 Total of Samples ? 3 3 4 20 14 1 1 4 6 10 1 7 51 1 - -- - - 3 - 79 15 2 10 8 5 21 14 11 4 6 10 3 94 naI2.0 Lpm) through open-face cassettes containing Miiiipore Type AA filters using battery-powered, portable pumps ( Mine Safety Appliances Company. Model G). Each sample wasanalyzed forasbesiosfibers usinga phase-contrast micro scope (Olympus Scries BH-P-2). Results Table I presents the results of analyses of bulk samples taken from sprayed fireproofing materials in I I buildings investi gated. Ten of the 11 buildings contain 2 to 15% chrysolite in the sprayed ceilings and one building contains 20 umosite in the sprayed material. Table II presents the results of analyses of 214 bulk sam ples collected from 127 office buildings throughout the U.S. from January 1978 to March 1982. Sixty-four buildings were sprayed with fireproofing materials consisting of 2 to 350 chrysolite. two buildings contained sprayed materials consisting of 2 to 60 amositc. and two buildings contained sprayed materials consisting of both amositc and chrysotile. No asbestos was found in the other 59 buildings. Tables 111 and IV and Figures I and 2 present detailed results of anal yses of 278 personal samples collected during renovation and during removal of sprayed materials in the buildings listed in Table I. The airborne asbestos fiber concentrations during renovation are presented by job titles, and fiber con centrations during removal of sprayed materials are pre sented by the removal methods, i.e.. dry and wet methods. The distribution of the results is presented in Figures I and 2. American Industrial Hygiene Association JOURNAL m 6/83 Tables Vand VI summarize the values of geometric mean (GM) and geometric standard deviations (GSD) during ren ovation and removal, respectively. Discussion Identification and Content of Asbestos in Sprayed Ceiling Material As presented in Table 1.10 of 11 buildings investigated contain 2 to 15% chrysotile in the sprayed materials; one building contains 2% amosite. According to the American Conference ol Governmental Industrial Hygienists (ACGIH).|S| chryso tile constitutes 95% of all asbestos used in North America, with amosite and crocidolite making up the other 5%. This conforms with the results presented in Table II. Clayton Environmental Consultants. Inc. analyzed 214 bulk samples collected from 127 buildings throughout the U.S. from Jan uary 1978 to March 1982. Table 11 indicates that 68 (54%) of 127 buildings contained 2 to 35% asbestos of some form. The type ol asbestos was identified as chrysotile in 94% of the 68 buildings, amosite in 3%. and both chrysotile and amosite were found in 3% of the buildings. Distribution of Airborne Asbestos Fiber Concentrations Various studies have pointed out that airborne concentra tions of dust, benzene and radioactive particles are better described by a lognormal dislribuiionl6'Sl than by a normal distribution. Limited information has been reported on the frequency distribution of airborne asbestos fiber concentra tions. This study consists of a total of 278 samples which 429 were analyzed for airborne asbestos fiber concentrations during renovation in buildings and during removal of sprayed materials. Frequency distribution of the data was 'served and is presented in Tables 111 and IVand Figures 1 .id 2. The data were plotted on lognormal probability paper and showed straight lines. It is concluded that airborne asbestos fiber concentrations are lognormally distributed, and GM and GSD best represent the data. Geometric mean is the 50% probability value and GSD is calculated from the following formula. ' 50r/l value Airborne Asbestos Fiber Concentrations During Renovation Renovation and maintenance activities are performed fre quently in buildings which contain sprayed fireproofing materials consisting of asbestos and other materials. The main activities are installation of partitions or walls, replace ment of air ducts and electrical wires, painting walls, and installation of carpets. Carpenters, electricians, sheet-metal workers and painters carry out this work. Tables III and V show the frequency distribution and geometric means of fiber concentrations bvjob titles of employees. The average exposure levels were highest for sheet-metal workers -- 0.19 fibers, cc. followed by carpenters and electricians -- both 0.13 fibers, cc. and lowest in painters -- 0.08 fibers/cc. Gen erally. the sheet-metal workers disturbed the sprayed mate rials more extensively (when they replaced ventilation sys tems) than did other workers. Painters did not directly disturb the sprayed ceilings. Eleven of 184 samples indicated fiber concentrations exceeding 2 fibers cc. the OS HA 8-hour, time-weighted average (TWA) permissible exposure limit (PEL).131 All workers except painters were exposed to average fiber concentrations exceeding the NIOSH-recommended standard of 0.1 fibers, cc for an 8-hour period.*101 ACGIH1111 adopted 8-hour. TWA threshold limit values (TLVs) by the type of asbestos as follows: 0.5 fibers, cc - amosite 2.0 fibers.- cc - chrysotile 0.2 fibers, cc - crocidolite 2.0 fibers/ cc - other forms ACGIH also lists all types of asbestos in a category of Ala. proven human carcinogens. In summary, workers, especially sheet-metal workers, carpenters and electricians, were exposed to average air borne fiber concentrations exceeding 0.1 fibers.'cc. but below both the OS HA PEL of 2 fibers- ccand ACGIH TLVs for chrysotile and amosite. Airborne Fiber Concentrations During Removal of Sprayed Material OSHA requires use of wet methods when practicableduring removal of asbestos ceiling insulation. This study was con- Asbestos Fiber Concentration, Fibers/cc Figure 1 -- Asbestos fiber concentrations during renovation activities. <30 Am. Ind Hyg. Assoc. J. (44) June. 1983 Asbestos Fiber Concentrations, Fibers/cc Figure 2 -- Asbestos fiber concentrations during removal of sprayed fireproofing materials. ducted during sprayed ceiling material removal using both drv methods and wet methods. Workers removed sprayed ft'ilini: materials using drv methods on the seventh floor of a seven-story building (Building C). Wet methods were not used because electrical equipment such as air handling machines and elevator controls was located on the seventh floor of the building. Removals using wet methods were performed in other buildings. During removal using dry methods, short-term air samplings were conducted for a period from 30 minutes to 60 minutes to prevent' particulate overloading of filtersamples. As presented in Tables IV and V|. and F gure 2. mean airborne fiber concentrations were sharply reduced from 16.4 fibers cc to 0.5 fibers cc by employing wet methods. Three of 79 samples showed fiber concentrations exceeding 100 fibers cc during dry removal. Sawyer"''1 reported average airborne fiber concentrations of 82.2 and 8.1 fibers, cc during removal of asbestos ceilings using dry and wet methods, respectively. Sawyer used arithmetic means instead of geometric means. There were eleven samples for dry removal in his paper. In summary. 8697 of samples taken during removal of sprayed materials using dry methods indicated fiber concen- TABLE V GM and GSO of Data Taken During Renovation Activity Job Title GM 84th Percentile Fibers/cc Fibers/cc GSD Carpenter Electrician Sheet*metal worker Painter 0.13 0.13 0.19 0.08 0.45 0.42 0.77 0.19 3.46 3.23 4.05 2.38 t rat ions exceeding the OSH A PEL of 2 fibers /cc. The con centrations sharply decreased to levels below the OSHA PEL when wet methods were used. Conclusions Based on the results of analyses of bulk samples collected from fireproofing materials sprayed on ceilings of buildings throughout the U.S.. and the results of sampling and anal yses of personal samples taken during renovation work in the buildings containing asbestos and during removal of sprayed materials, it is concluded that: (1) Fifty-four percent of the 127 buildings surveyed con tain 2 to 359-t asbestos in the sprayed materials. The asbestos was identified as chrvsotile in 9497 of the buildings and as amosite in 397. Both chrvsotile and amosite were identified in 397 of the buildings. (2) The frequency of airborne asbestos Fiber concentra tions was distributed lognormallv. Therefore, geo metric means and geometric standard deviations best represent the data. (3) During renovation activities in the buildings contain ing asbestos, workers, such as sheet-metal workers. TABLE VI GM and GSD of Data Obtained During Removal of Fireproofing Material by Removal Methods Removal Method GM 84th Percentile Fibers/cc Fibers/cc GSD Dry 16.4 51.8 3.16 Wet 0.5 1.0 2.0 American Indust'ial Hygiene Association JOURNAL (44) S/83 431 carpenters, and electricians, were exposed to average airborne fiber concentrations exceedingO. I fibers cc. but below the OSHA PEL of 2 fibersi cc. (4) During removal of sprayed materials containing asbestos, workers were exposed to extremely high fiber concentrations when dry methods were used. The fiber concentrations sharply decreased to levels below the OSHA PEL when wet methods were used. References 1. Reitze. W.B.. W.J. Nicholson, D.A. Holaday and I.J. Selikoff: Application of Sprayed Inorganic Fiber Containing Asbestos: Occupational Health Hazards. Am. Ind. Hyg. Assoc. J.33:178-191(1972). 2. U.S. Environmental Protection Agency (EPA): 40 CFR 61. National Standards for Hazardous Air Pollutants: Asbestos. Fed Reg. 38/66)11973). 3. U.S. Department of Labor: General Industry. Occupational Safety and Health Administration Standards, Subpart Z. Part 1910, Title 29 of the Code of Federal Regulations (1978). 4. National Institute for Occupational Safety and Health (NIOSH): Asbestos Fibers in Air. Method No. P&CAM 239, NIOSH Manual of Analytical Methods. 2nd Ed., Vol. 1. DHEW (NIOSH) Publication No. 77-157-A, Cincinnati, Ohio(1977). 5. American Conference of Governmental Industrial Hygien ists (ACGIH): Documentation of the Threshold Limit Values. 4th Ed. ACGIH, Cincinnati. Ohio (1980). 6. Breslin. A.J.. L. Ong, H. Glauberman. A.C. George and P. LeClare: The Accuracy of Dust Exposure Estimates Obtained from Conventional Air Sampling. Am. Ind. Hyg. Assoc. J. 28:56-61 (1967). 7. Jones. A. R. and R.S. Brief: Evaluating Benzene Exposures. Am. Ind. Hyg. Assoc. J. 32:610-613 (1971). 8. Sherwood. R.J.: On the Interpretation of Air Sampling for Radioactive Particles. Am. Ind. Hyg. Assoc. J. 27.98- 109(1966). 9. Leidel. N.A., K.A. Busch and J.R. Lynch: Occupational Exposure Sampling Strategy Manual. DHEW (NIOSH) Publi cation No. 77-173. Cincinnati. Ohio (1977). 10. NIOSH: Revised Recommended Asbestos Standard. DHEW (NIOSH) Publication No. 77-169. Cincinnati, Ohio (1976). 11. ACGIH: TLVs Threshold Limit Values for Chemical Sub stances in Work Air Adopted by ACGIH for 1982. ACGIH, Cincinnati, Ohio (1982). 1 2. Sawyer, R.N.: Asbestos Exposure in a Vale Building: Analy sis and Resolution. Environ. Res. 73:146-169 (1977). 12 July 19X2: Revised 27 January I9X.1 . 432 Am. Ind. Hyg. Assoc. J. (44) June. 1983