Document 22DQEmyZgDR3QvNK09QxZ9Kr

This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organisation, or the World Health Organization. Environmental Health Criteria 203 CHRYSOTILE ASBESTOS First draft prepared by Dr G. Gibbs, Canada (Chapter 2), Mr BJ. Pigg, USA (Chapter 3), Professor W.J. Nicholson, USA (Chapter 4), Dr A. Morgan, UK and Professor M. Lippmann,- USA (Chapter 5), Dr J.M.G. Davis, UK and Professor B.T. Mossman, USA (Chapter 6), Professor J.C. McDonald, UK, Professor PJ. Landrigan, USA and Professor W.J. Nicholson, USA (Chapter 7), Professor H. Schreier, Canada (Chapter 8). Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization, and produced within the framework of the Inter-Organization Programme for the Sound Management of Chemicals. World Health Organization Geneva, 1998 EHC 203: Chrysotile asbestos asbestos-cement plant of 1.5-6.3 17ml during 1956. Later, based on direct measurements, values were 0.3-5.0 f/ml in 1969 and 0.9-1.7 f/ml in 1975. Higashi et al. (1994) reported geometric average concen trations of 0.05-0.45 f/ml measured in area samples and 0.05-0.78 17ml in personal samples of an asbestos-cement plant. Few data are available in die open literature on exposures encountered during installation of asbestos-cement products. It would be expected that cutting, sanding, drilling or otherwise abrading asbestos-cement without efficient ventilation controls would give rise to high exposures (Nicholson, 1978). Weiner et al. (1994) reported concentrations in a South African workshop in which chrysotile asbestos-cement sheets were cut into components for insulation. The sheets were cut manually, sanded and subsequently assembled. Initial sampling showed personal sample mean concentrations of 1.9 f/ml for assembling, 5.7 f/ml for sweeping, 8.6 f/ml for drilling and 27.5 f/ml for sanding. After improvements and i clean-up of the work environment, the concentrations were 0.5-1.7 I f/ml. Nicholson (1978) reported concentrations of0.33-1.47 f/ml in a room during and after sawing and hammering of an asbestos-cement r. panel. i 4.1.4 Friction products Skidmore & Dufficy (1983), based on simulated past conditions (Table 10), and McDonald et al. (1984) reported data on workplace exposures during friction product manufacturing. McDonald et al. (1984) reported that in the 1930s estimated average dust levels were 35-180 mpcm (1-5 mpcf) in 67% of analysed Vi locations, while in the 1960s average dust levels were below 7 mpcm (0.2 mpcf) at 38% of locations and below 18 mpcm (0.5 mpcf) at 67% of locations in which measurements were obtained. I 4.1.5 HWBUI0011461 Occupational and Environmental Exposure Levels Table 10. Average concentrations of chrysotile fibres (f/ml) longer > 5 pm from woven asbestos products during various periods Storage/distribution Preparation Impregnation/forming Grinding Drilling, boring Inspection Packing Office/laboratory Pre-1931 >20 >20 >20 >20 >20 >20 >20 10-20 1932-1950 2-5 0-20 2-5 5-10 2-5 2-5 1-2 <0.5 1951-1969 1970-1979 2-5 2-5 1-2 2-5 1-2 1-2 0.5-1 <0.5 0.5-1 1-2 0.5-1 0.5-1 1-2 0.5-1 <0.5 <0.5 `Skidmore & Dufficy (1983) Kimura (1987) reported geometric mean fibre concentrations of 10.2-35.5 f/ml in 1970-1975, and 0.24-5.5 f7ml in 1984-1986 in spin ning and grinding of friction products in Japan. A considerable number ofreports have included airborne asbestos concentrations during maintenance and replacement ofvehicle brakes. In the early period, poor or no engineering control measures were utilized, resulting in high total dust exposure. This was particularly so during grinding of brakes and compressed air blowing off dust, both operations of very short duration. Significantly, lower levels were measured when engineering controls were introduced. An overview of air concentrations measured during maintenance and replacement of asbestos-containing vehicle brakes is presented in Table 11. 1.5 Exposure of building maintenance personnel The subject of asbestos exposure of maintenance personnel in buildings has been raised recently and particularly by US OSHA (1994). HWBUI0011462 Rodelsperger et ai., 1986 Kauppinen & Korhonen, 1987 Kauppinen & Korhonen, 1987 W0O3 C0053si 3 to CO CO to CD 05 CD CO CO CD CD cc a> 05 r* r s8Cr r05 T" r 15 Iw E c 3 N05 co" i. E `C o b&- 15 xo: O' <0 S 15 E o K CO N o> V IS *-* Q E o & 8 2 o0 1 xfw:3 c 2 8 2 00 xQ; *E CD 2 to oo 05 15 c x: to oo CT-D~ 15 c x: -5 *0 GO 0> v-- C o> CO 3 CO C Qj > FW s>?> >% ss 8 t/> 2 $ CL o b 12 oQ 00 0 E? a s CD 05 CO JZ C C 3 x: x: 0 o a: O O C fibres longer than 5 pm, blowing off, grinding, trucks trucks and buses Table 11. Asbestos air concentrations measured during maintenance and replacement of vehicle brakes s 3D s 5 .pE> tc3 Otz) o oc 1a St jq ,,S Tc5 -ac 0= 05 5C JQ w c So3 Ol 2 3=8$ !" ro -o* r-- ScoCb3O. Q. o 05 E 3. in cra k. 0 CCD o u0 05 c `CC CD O 0C5 > JoQ E3. tn cra U0, CCoD 00 JO C05 c06c5 s0fcT 0c5 1 .o E 3 ID C CD S rE- u05 C o <0 5 H f* c J5 s= 1 If c t0o) CO to 05 lO q s> S oi (M N A d > CoO to d co 5 ovo 5-108 < 0.05b 0.01-0.26 Kauppinen & Korhonen, 1987 rTGo-O>" 0Q*"9> CoNT"O>"-,, CCOO 03 15 Q> >* <1> xCO: 140>5)* XT>0O5J3 c0CaU3>i CO cco 1<045-)* 0Qhoo).. COOO 03 oo <o a > o 2 a> E coM eCoO <CaconO> 03 o> t. o TOtf5i 'aa>. c 8 2a. (<aU0> blowing off Jq X? SCCOB, 1k COOM d V JS xO> -fofl JQS. *E0)> < li I _oE 15 1fe5 .CO ^00 O-to 1 c Si a CM <ctd 8o..-E(mt 11 *s.XS C 8 , Sid a o V o v Orio d d ro a> -S -- {ts3 3w > OS2 ffi CL JB _HrQa i> *=S i < } j HWBUI0011464