Table I.
Summary Respirable Dust Concentrations by Manufacturer Comparing Drills with Dust Controls Off Versus On
| Number of Samples | Geometric Mean (mg/m3) | Geometric Standard Deviation | GM 95% CI | Range (mg/m3) | p-Value | |
|---|---|---|---|---|---|---|
| Manufacturer 1 | ||||||
|
| ||||||
| Control OFF | 24 | 54 | 1.3 | 48.6 – 60.0 | 30 – 82 | <0.0001 |
| Control ON | 24 | 3.0 | 1.5 | 2.6 – 3.5 | <LOD – 6.0 | |
| Manufacturer 2 | ||||||
|
| ||||||
| Control OFF | 21 | 57 | 1.2 | 52.7 – 61.6 | 39 – 79 | <0.0001 |
| Control ON | 21 | 5.3 | 1.9 | 4.0 – 7.0 | <LOD – 12 | |
| Overall | ||||||
|
| ||||||
| Controls OFF | 45 | 55 | 1.3 | 50.9 – 59.4 | 30 – 82 | <0.0001 |
| Controls ON | 45 | 3.9 | 1.8 | 3.3 – 4.6 | <LOD – 12 | |