Table 1.
Mean years of employment with SD, and geometric mean (GM), geometric SD (GSD) and estimated arithmetic mean (AM) of annual intensity of exposure to specific exposure factors, by department and period of employment, for 1687 male long-term Norwegian silicon carbide industry workers employed during 1913–2003
| Employment before 1960 | Employment after 1959 | |||||||
| GM | GSD | AM* | GM | GSD | AM* | |||
| Furnace department (n†) | 232 | 584 | ||||||
| Years of exposure (mean/SD) | 7.2 (6.4) | 9.5 (7.3) | ||||||
| Total dust (mg/m3) | 9.3 | 3.1 | 18 | 3.8 | 3.1 | 7.1 | ||
| Respirable dust (mg/m3) | 1.1 | 2.5 | 1.6 | 0.55 | 2.5 | 0.84 | ||
| Respirable quartz (mg/m3) | 0.015 | 3.4 | 0.033 | 0.0045 | 3.5 | 0.0096 | ||
| Respirable cristobalite (mg/m3) | 0.014 | 6.3 | 0.074 | 0.0022 | 4.6 | 0.0072 | ||
| Respirable SiC (mg/m3) | 0.12 | 4.8 | 0.41 | 0.064 | 5.4 | 0.27 | ||
| Fibres (fibres/cm3) | 0.33 | 3.1 | 0.62 | 0.20 | 2.6 | 0.31 | ||
| Processing department (n†) | 166 | 537 | ||||||
| Years of exposure (mean/SD) | 9.4 (8.3) | 9.5 (7.3) | ||||||
| Total dust (mg/m3) | 12 | 2.1 | 16 | 5.2 | 2.2 | 7.2 | ||
| Respirable dust (mg/m3) | 1.0 | 2.3 | 1.4 | 0.60 | 2.2 | 0.82 | ||
| Respirable quartz (mg/m3) | 0.0056 | 2.3 | 0.0078 | 0.0032 | 2.2 | 0.0044 | ||
| Respirable cristobalite (mg/m3) | 0.0075 | 2.3 | 0.011 | 0.0019 | 2.2 | 0.0026 | ||
| Respirable SiC (mg/m3) | 0.67 | 2.9 | 1.2 | 0.34 | 2.7 | 0.55 | ||
| Fibres (fibres/cm3) | 0.057 | 2.5 | 0.088 | 0.030 | 2.5 | 0.047 | ||
| Maintenance department (n†) | 187 | 453 | ||||||
| Years of exposure (mean/SD) | 9.6 (9.1) | 10.3 (7.8) | ||||||
| Total dust (mg/m3) | 5.6 | 1.9 | 6.9 | 3.5 | 2.1 | 4.7 | ||
| Respirable dust (mg/m3) | 0.55 | 1.8 | 0.65 | 0.52 | 2.1 | 0.68 | ||
| Respirable quartz (mg/m3) | 0.0039 | 1.8 | 0.0046 | 0.0035 | 2.1 | 0.0047 | ||
| Respirable cristobalite (mg/m3) | 0.0038 | 1.8 | 0.0046 | 0.0018 | 2.1 | 0.0023 | ||
| Respirable SiC (mg/m3) | 0.17 | 1.9 | 0.20 | 0.12 | 2.0 | 0.15 | ||
| Fibres (fibres/cm3) | 0.19 | 1.9 | 0.23 | 0.10 | 2.4 | 0.14 | ||
| Other, low exposed (n†) | 88 | 276 | ||||||
| Years of exposure (mean/SD) | 12.3 (10.7) | 11.6 (8.7) | ||||||
| Total dust (mg/m3) | 0.22 | 3.8 | 0.53 | 0.11 | 3.5 | 0.24 | ||
| Respirable dust (mg/m3) | 0.021 | 3.7 | 0.048 | 0.015 | 3.4 | 0.031 | ||
| Respirable quartz (mg/m3) | 0.00020 | 3.7 | 0.00047 | 0.00011 | 3.4 | 0.00023 | ||
| Respirable cristobalite (mg/m3) | 0.00025 | 3.8 | 0.00062 | 0.00047 | 3.6 | 0.0011 | ||
| Respirable SiC (mg/m3) | 0.0077 | 3.7 | 0.018 | 0.0050 | 3.3 | 0.010 | ||
| Fibres (fibres/cm3) | 0.0072 | 3.4 | 0.015 | 0.0044 | 3.3 | 0.0088 | ||
*
AM estimated from GM and GSD, as described by Seixas et al,12 using the formula AM=GM*exp (0.5(ln GSD)2).
†
n, Number of workers. The sum of n is more than 1687, as each person may have been employed in several departments and in both periods.