NYC-WTC_000202744

NYC 9/11 Public Portal Document 1-24-02;12:30PM;NYC LSW Deoartment ;12’23Si8765 # 12/ 55 UbtH UNIT Rn. 7345 202 324 9235 P.00/43

Industrial Hygierie Survey Federal Bureau of Investigation, Staten Island, NY

3.0 Survey Methods

Personal exposure monitoring was conducted for fibers in air, respirable silica dust, total dust, heavy metals including lead, and volatile organic compounds. Personal sampling pumps were attached to a representative number of workers and were used to collect air from the breathing zone of the worker. The samplers were calibrated in the field with a rotameter, which was calibrated against a Gilibrator (bubblemeter). The personal samples give the best indication of the level of exposure to the worker. A small numbej^Twea samples were also collected. In most cases these were taken along the perimeter work zone in order to verify that respirators were not required in clean areas. In some cases the area samples were taken within the debris field. The following summarizes the analytical methods used for this survey:

Asbestos Fibers in air were collected on 25 millimeter mixed cellulose ester filters at flow rates between 1.2 to 2.0 liters per minute (LPM). The samples were analyzed following the National Institute I of Occupational Safety and Health (NIOSH) method 7400 by the Federal Occupational Health Environmental Lab located in Denver Colorado. Some of the samples were selected for additional analysis by transmission electron microscopy (TEM) following the NIOSH method 7402. Sample results are reported in fibers per cubic meter of air (f/cc).

Asbestos bulk samples were also analyzed for asbestos content using polarizing light microscopy and additional analysis was done on selected samples using TEM. Results are reported in % asbestos by weight.

Metals Each sample was collected on mixed cellulose ester 37-miIlimeter filters. The sample was collected using persona! sampling pumps operated at 2.0 liters per minute. The sample media was prepared and analyzed by Galson Laboratories of Syracuse New York. They are an American Industrial Hygiene Association (AIHA) accredited lab. Results are reported in milligrams of metal contaminant per cubic centimeter of air (mg/M3). For some of the samples metals scan was performed for 23 metals using inductively coupled plasma.

Volatile Organic Compounds Volatile organic compounds were collected using charcoal tubes and personal samplers operated at a flow rate of 0.2 liters per minute. The samples were analyzed by the Galson Laboratory using gas chromatography. Results are reported in micrograms of contaminant per sample.

Total Dust Total dust samples were collected on 37 millimeter, 5 micron preweighed polyvinyl chloride filters at a flow rate of 2 1pm. The samples were prepared and analyzed by Galson Laboratory. Results are reported in milligrams per cubic meter. Respirable Dust Respirable dust samples were collected on 37 millimeter; 5 micron preweighed polyvinyl chloride filters. The cassettes were mounted in a nylon cyclone (MSA) and respirable dust was

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NYC-WTC_000202750