Please Note:
Sample Type: A = Area; P = Personal; S=Screen
PEL = OSHA Permissible Exposure Limit (usually a 480 minute exposure, value listed for reference)
Non-Detected (ND) = Exposures less than Reporting Limit
NA = Not Available. Information not recorded when sample was taken.

^a = Results reported are time weighted averages for the actual sampling period.
^b = For comparative purposes only, the TWA > PEL box is checked Y if the actual TWA is greater than the OSHA 8-hour PEL.  Does not necessarily represent a legal PEL violation. For additional information, see Information on Sampling Results.

Total Fiber sample results may also include asbestos fibers.

Please Note:
The 8-hour OSHA Permissible Exposure Limit (PEL) for Respirable Dust containing quartz is determined individually for each sample, using the following formula:

PEL = 10mg/m³ ÷ (%SiO₂+2), where %SiO₂ refers to the amount of quartz measured in that sample.

This calculated PEL is compared with the Respirable Dust sample result to determine whether there is an overexposure. If there is no quartz found in a sample, the PEL for that Respirable Dust sample is 5.0 mg/m³, equivalent to the Particulates Not Otherwise Regulated PEL. The PEL for respirable dust containing quartz varies depending on the concentration of quartz in the sample. The higher the concentration of quartz the lower the PEL. For additional information, see crystalline silica (quartz) and the OSHA PEL.

^a = Results reported are time weighted averages for the actual sampling period.
^b = For comparative purposes only, the TWA > PEL box is checked Y if the actual TWA is greater than the OSHA 8-hour PEL. Does not necessarily represent a legal PEL violation. For additional information, see Information on Sampling Results.