Exposures in the refineries' production process groups
| Maintenance | Digestion | Clarification | Precipitation | Calcination or shipping | Residue | Descale | |
| Bauxite (mg/m3): | |||||||
| Refinery 1 | 2.85 (n=10) (0.4–17.4) | 1.53 (n=12) (0.22–8.6) | 2.8 (n=7) (0.64–13.3) | — | — | 0.69 (n=6) (0.3–2) | 0.88 (n=3) (0.59–1.56) |
| Refinery 2 | 0.66 (n=11) (0.1–2.7) | 0.53 (n=11) (<LD*–4.2) | — | — | — | — | 4.0 (n=2) (1.1–14.5) |
| Refinery 3 | 0.68 (n=3) (0.2–1.8) | 0.9 (n=12) (0.1–33.1) | — | — | — | — | — |
| Alumina (mg/m3): | |||||||
| Refinery 1 | 1.56 (n=26) (0.2–11.6) | — | — | — | 2.18 (n=58) (0.2–41.6) | — | — |
| Refinery 2 | 1.37 (n=5) (0.6–6.3) | — | — | — | 0.98 (n=10) (0.3–3.6) | — | — |
| Refinery 3 | — | — | — | — | 1.2 (n=15) (0.3–4.7) | — | — |
| Caustic mist (mg/m3): | |||||||
| Refinery 1 | — | — | — | 0.34 (n=19) (0.1–0.8) | — | — | — |
| Refinery 2 | 0.2 (n=19) (0.02–4) | — | 0.46 (n=27) (0.1–2.3) | — | — | — | 0.56 (n=11) (0.1–1.0) |
| Refinery 3 | 0.17* (n=8) (0.05–0.6) | 0.11* (n=6) (0.05–0.6) | 0.09 (n=9) (0.05–1.1) | — | 0.19* (n=18) (0.05–0.9) | — | 0.4* (n=12) (0.05–3.5) |
Geometric mean (range) 4 hour time weighted averages except*, which are 15 minute samples.
<LD=below the limit of detection.