OSHA Asbestos Air Monitoring Summary, Financial District, Jan 2002

NYC 9/11 Public Portal Document

OSHA SAMPLING RESULTS SUMMARY AS OF- 1/2/02

Asbestos; A total of 931 air monitoring samples for asbestos have been taken. Fronl 9/13 -9/21, 177 samples were taken in the financial district. They were taken on OSHA persoimel as they walked within certain predetermined zones. Results revealed asbestos concentrations ranging from ND (none detected) to .037 free., well below OSHA’s permissible exposure limit (PEL) of. 1 free. After 9/21, sampling focused on the rubble pile and those workers working-on or immediately next to it. 82 o "the samples analyzed exceeded OSHA’s limit via PCM analysis. However, upon further iinalysis using discriminating counting methods and/or TEM analysis, the number of asbestos fibers found dropped dramatically to below detectable levels or well below .1 free.

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 CiSHA permissible exposure limit of 50 PPM.

Noise: OSHA is monitoring the noise exposures oi'employees who perform (or work near) noisy operations such asjadc 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 466 silica samples show no detectable leveLs of airborne silica. However, fifteen exposures exceeded the PEL. The highest s ample result was approximately nine times the OSHA limit (])re-drillers working on tlie 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 brealdng up of concrete in the pit; 3) while core drilling the concrete slurry wall, and 4) while clupping concrete witli power tools during demolition activities at 7 WTC’s parking garage. Most of the work lareas 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 614 samples for (VOCs) such as acetaldehyde, acrolein, acrylonitrile, benzene, 2-butanone, carbofurans, PCBs, ethyl benzene, formaldehyde. Freon R-22 (chlorodiflouromethane), hexone, isocyanates (e.g. MDL TDI), percliloroethylene, phosgene, styrene, toluene, 1-3 butadiene, trichloroethylene, vinyl cldoride, 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 48 samples for inorganic acids such as hydrochloric, phosphoric, and sulfuric acids. One sarnple for sulfuric acid was found to exceed OSHA’s permissible exposure limit (PEL) of 1 mg/m'. Additional sampling results are pending.

Page 1 of 2

CITY_21MC100_011109455

NYC-WTC_000186186