NYC-WTC_000205201

NYC 9/11 Public Portal Document

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OSHA SAMPLING RESULTS SUMMARY AS OF 2/4/02

Asbestos: A total of 963 samples (excluding bulk and blank samples) for asbestos have been taken. From 9/13 -9/21,177 samples were taken in the financial district. They were taken on OSHA personnel as they walked within certain predetermined zones. Results revealed asbestos concentrations ranging from ND (none detected) to .037 f/cc., well below' OSHA’s permissible exposure limit (PEL) of 0.1 f/cc. After 9/21, sampling focused on the rubble pile and those workers working on or immediately next to it. 132 of the samples analyzed exceeded OSHA’s limit via PCM analysis. However, upon further analysis using discriminating counting methods and/or TBM analysis, the number of asbestos fibers found dropped dramatically to below detectable levels or well below .1 f/cc.

Carbon Monoxide: A total of 108 personal samples of workers on the rubble pile showed results ranging from 1 ppm to 34 ppm which are well below the OSHA permissible exposure limit of 50 PPM.

Noise: OSHA is monitoring the noise exposures of employees who perform (or work near) noisy operations such as jack hammering and drilling. To date the 94 samples collected indicate that employee noise exposures range from 73.7 dBA to 94.5 dBA. One personal sample and one area sample taken during core drilling operations have exceeded the applicable permissible exposure limit of 90 dBA. Accordingly, OSHA continues to recommend the use of appropriate hearing protection in noisy operations.

Total Dust (PNOR) A total of 104 samples (excluding bulk and blank samples) for total dust in and around the rubble pile were taken. Two samples were found to be in excess of the PEL for Total dust (15mg/m3). The highest exposure was found on one operator who was exposed at approximately 4X PEL. Respirable Silica: The overwhelming majority of 585 silica samples (excluding bulk and blank samples) show no detectable levels of airborne silica. However, 34 exposures exceeded the PEL. The highest sample result was approximately twenty-one times the OSHA limit (jack hammering concrete 16 feet below grade). The other elevated exposures were approximately one to fourteen times file OSHA limit. These exposures occurred during: 1) pre-drilling /slurry wall 2) jack hammering, 3) rubble removal and loading operations near the Winter Garden; 4) during the breaking up of concrete in the pit; 5) while drilling the concrete slurry wall, 6) flagging operations in pit, and 7) while chipping concrete with

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NYC-WTC_000205201