TABLE II.
GM (sample size) and Range of 8-Hour Respirable Dust and Silica Concentrations
| Company A
|
Company B
|
Company C
|
Company D
|
|||||
|---|---|---|---|---|---|---|---|---|
| GM (n) | Range (mg/m3) | GM (n) | Range (mg/m3) | GM (n) | Range (mg/m3) | GM (n) | Range (mg/m3) | |
| Respirable dustA | 0.83 (16) | 0.2–2.2 | 0.86 (8) | 0.2–1.8 | 1.19 (7) | 0.7–3.6 | 0.89 (7) | 0.3–2.9 |
| Respirable silica | 0.12 (16) | 0.04–0.32 | 0.14 (8) | 0.04–0.25 | 0.16 (7) | 0.07–0.44 | 0.14 (7) | 0.04–0.44 |
Note: The minimum quantifiable concentration (MQC) for respirable silica was 0.04 mg/m3. Two of the 7 results for Company C were based on partial shifts and not a typical 8-hr TWA.
Range of general industry OSHA PELs for 8-hr respirable dust containing silica for Companies A, B, C, and D are 0.51–0.87, 0.42–0.67, 0.53–0.85, and 0.49–0.74 mg/m3, respectively.