Process N fiber concentrations (f/ml) -GM(GSD)   -Range
Total a Asbestos b Rock wool c
  Feeding of raw material 12   0.96(1.29)
0.71-1.50
  0.38(1.29)
0.28-0.60
  0.58(1.29)
0.43-0.90
  Milling & mixing 8   0.54(1.61)
0.30-1.10
  0.22(1.61)
0.12-0.44
0.32(1.61)
0.18-0.66
  Baking processes 10   0.36(1.29)
0.25-0.53
  0.14(1.28)
0.10-0.21
0.21(1.30)
0.15-0.32
  Drilling & beveling 10   0.55(1.63)
0.27-1.02
  0.22(1.63)
0.11-0.41
  0.33(1.63)
0.16-0.61
  Cutting 8   0.56(1.21)
0.43-0.76
  0.23(1.21)
0.17-0.30
0.33(1.21)
0.26-0.46
  Grinding & finishing 8   0.38(1.30)
0.23-0.48
  0.16(1.30)
0.09-0.19
0.22(1.30)
0.14-0.29
  Total 56   0.54(1.61)
0.23-1.50
  0.22(1.61)
0.09-0.60
0.32(1.62)
0.14-0.90
Table 1: Fiber concentrations during automobile brake manufacture operation.