Table 1.
Concentration and cumulative respirable metal dust exposure by different work unit
| Work unit | No of workers | No of samples | Time Weight Average (mg/m3) 8-h TWA |
Cumulative respirable metal dust exposure (mg/m3 × year) |
||||
|---|---|---|---|---|---|---|---|---|
| Total number | 472 | 192 | ||||||
| Metal dust | Co | Cr(VI) | Ni | Co | Cr(VI) | Ni | ||
| USECHH PEL (mg/m3) | 0.1 | 0.05 | 1.5 | Mean | ||||
| Furnace | ||||||||
| Supervisor & Foreman | 3 | 1 | 0.15 | 0.11 | 0.60 | 3.88 | 2.90 | 7.19 |
| Electric Arc Furnace controller | 3 | 1 | 0.09 | 0.10 | 0.05 | 1.23 | 1.39 | 4.33 |
| Melter | 18 | 10 | 0.15 | 0.15 | 0.66 | 11.84 | 3.47 | 11.46 |
| Ladle furnace | ||||||||
| Supervisor | 2 | 1 | 0.04 | 0.13 | 0.15 | 0.43 | 0.70 | 4.00 |
| Controlling room operator | 3 | 1 | 0.03 | 0.14 | 0.07 | 0.05 | 0.27 | 1.26 |
| Melter | 8 | 6 | 0.10 | 0.14 | 0.18 | 6.94 | 2.30 | 12.91 |
| Ladle handling | 0.04 | |||||||
| Supervisor | 2 | 1 | 0.10 | 0.02 | 0.49 | 4.80 | 0.41 | 8.64 |
| Controlling room operator | 3 | 1 | 0.11 | 0.08 | 0.07 | 0.85 | 0.47 | 1.58 |
| Ladleman | 8 | 6 | 0.15 | 0.12 | 0.63 | 5.26 | 1.63 | 9.11 |
| Continuous casting machine (MC-5) | ||||||||
| Supervisor & Foremen In charge | 6 | 2 | 0.12 | 0.02 | 0.49 | 4.80 | 0.41 | 8.64 |
| Controlling room operator | 3 | 1 | 0.11 | 0.08 | 0.07 | 0.85 | 0.47 | 1.58 |
| Caster | 30 | 11 | 0.19 | 0.12 | 0.63 | 5.26 | 1.63 | 9.11 |
| Continuous casting machine-Concast | ||||||||
| Supervisor & Foremen In Charge | 6 | 2 | 0.12 | 0.14 | 0.60 | 2.91 | 1.28 | 5.38 |
| Controlling room operator | 3 | 1 | 0.10 | 0.07 | 0.05 | 0.54 | 0.87 | 2.82 |
| Caster | 30 | 11 | 0.16 | 0.16 | 0.64 | 3.88 | 3.48 | 16.64 |
| Scrap bay | ||||||||
| Supervisor | 6 | 2 | 0.10 | 0.11 | 0.55 | 3.82 | 2.05 | 10.4 |
| Heavy equipment driver | 30 | 11 | 0.14 | 0.15 | 0.60 | 4.83 | 2.20 | 12.19 |
| Crane operation | ||||||||
| Supervisor | 6 | 2 | ND | 0.01 | 0.10 | 0 | 1.44 | 0.58 |
| Crane operator | 30 | 11 | ND | 0.02 | 0.10 | 0 | 1.88 | 1.12 |
| DR shed | ||||||||
| Supervisor | 6 | 1 | 0.13 | 0.12 | 0.09 | 0.72 | 0.33 | 0.19 |
| Material handling technician | 30 | 11 | 0.15 | 0.15 | 0.17 | 0.88 | 0.60 | 0.22 |
| DR Cleaning | ||||||||
| Supervisor | 3 | 1 | 0.15 | 0.11 | 0.05 | 1.80 | 0.94 | 0.26 |
| DR technician | 32 | 11 | 0.16 | 0.13 | 0.17 | 4.29 | 1.40 | 0.50 |
| Product handler | 32 | 11 | 0.17 | 0.13 | 0.17 | 10.27 | 1.85 | 0.76 |
| DR operation | ||||||||
| Supervisor | 3 | 1 | 0.10 | 0.09 | 0.13 | 2.29 | 1.96 | 0.56 |
| DR man | 32 | 11 | 0.14 | 0.11 | 0.14 | 4.12 | 3.15 | 0.58 |
| Fabrication | ||||||||
| Supervisor | 3 | 1 | 0.10 | 0.11 | 0.24 | 0.25 | 0.80 | 0.63 |
| Fabricator | 8 | 6 | 0.12 | 0.13 | 0.54 | 1.78 | 1.59 | 0.46 |
| Welder | 8 | 6 | 0.14 | 0.19 | 0.67 | 1.40 | 3.07 | 2.74 |
| Refractory | ||||||||
| Supervisor | 3 | 1 | 0.02 | 0.15 | 0.02 | 0.24 | 2.99 | 0.70 |
| Refractory man | 8 | 6 | 0.04 | 0.16 | 0.08 | 0.48 | 5.43 | 1.70 |
| Raw material handling | ||||||||
| Supervisor | 3 | 1 | 0.12 | 0.10 | 0.45 | 1.31 | 1.98 | 7.13 |
| Raw material handler | 10 | 7 | 0.15 | 0.14 | 0.60 | 2.79 | 2.00 | 7.43 |
| Upstream conveyor | ||||||||
| Supervisor | 3 | 1 | 0.10 | 0.10 | 0.15 | 2.17 | 1.08 | 7.13 |
| Conveyor man | 11 | 7 | 0.14 | 0.16 | 0.18 | 3.71 | 2.33 | 7.43 |
| Machining & mechanical | ||||||||
| Supervisor | 3 | 1 | 0.03 | 0.03 | ND | 0.05 | 0.15 | 0 |
| Mechanics | 8 | 6 | 0.05 | 0.05 | ND | 0.14 | 0.19 | 0 |
| Electrical & Instrumentation | ||||||||
| Supervisor & engineers | 3 | 1 | 0.01 | 0.03 | 0.11 | 0.08 | 0.10 | 0.18 |
| Instrument technician | 8 | 6 | 0.02 | 0.04 | 0.12 | 0.16 | 0.18 | 0.38 |
| Electrician | 8 | 6 | 0.02 | 0.06 | 0.09 | 0.15 | 0.16 | 0.35 |
| Logistics/workshop | ||||||||
| Mechanics | 11 | 7 | ND | ND | ND | 0 | 0 | 0 |
Abbreviation: PEL – Permissible Exposure Limit; ND – Not detected.