NYC-WTC_000205503

NYC 9/11 Public Portal Document

OSHA SAMPLING RESULTS SUMMARY AS OF 12/29

Asbestos: A total of 910 air monitoring 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 .1 f/cc. After 9/21, sampling focused on the rubble pile and those workers working on or immediately next to it. 82 of the samples analyzed exceeded OSHA’s limit via PCM analysis. However, upon further analysis using discriminating counting methods and/or TEM analysis, the number of asbestos fibers found dropped dramatically to below detectable levels or well below .1 f/cc.

Carbon Monoxide: A total of 98 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 79 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. Respirable Silica: The overwhelming majority of the 450 silica samples show no detectable levels of airborne silica. However, fourteen exposures exceeded the PEL. The highest sample result was approximately nine times the OSHA limit (pre-drillers working on the slurry or “bathtub” wall). The other twelve elevated exposures were approximately one to seven times the OSHA limit. These exposures occurred during: 1) rubble removal and loading operations near the Winter Garden; 2) during the breaking up of concrete in the pit; 3) while core drilling the concrete slurry wall, and 4) while chipping concrete with power tools during demolition activities at 7 WTC’s parking garage. Most of the work areas where apparent overexposures to silica occurred were in the rubble pile; an area where OSHA continues to encourage the use of respiratory protection. Organic Compounds: OSHA has taken 608 samples for (VOCs) such as acetaldehyde, acrolein, acrylonitrile, benzene, 2-butanone, carbofurans, PCBs, ethyl benzene, formaldehyde. Freon R-22 (chlorodiflouromethane), hexone, isocyanates (e.g. MDI, TDI), perchloroethylene, phosgene, styrene, toluene, 1-3 butadiene, trichloroethylene, vinyl chloride, glutaraldehyde, and xylene. Screening samples initially showed elevated levels of some organic chemicals resulting from the fires burning in the rubble pile. Subsequent personal and area samples show worker exposure levels to be below OSHA limits. However, one personal sample result for a benzene sample taken was found to be at the 8-hr. OSHA Allowable Limit concentration of 1 ppm. This was found on a backhoe operator moving debris on 10/7/01. See information below for polynuclear aromatics. Freon R-22, phosgene and dioxin.

Inorganic Acids OSHA has taken approximately 46 samples for inorganic acids such as hydrochloric, phosphoric, and sulfuric acids. One sample for sulfuric acid was found to exceed OSHA’s permissible exposure limit (PEL) of 1 mg/m\ Additional sampling results are pending.

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NYC-WTC_000205503