EPA Special Investigative Audit Report, WTC Site, Nov 2001

NYC 9/11 Public Portal Document

Asbestos

As of November 9*, 22506 lines of data representing the analysis of 4176 samples for total fiber concentration, asbestos fiber concentration, or percentage asbestos had been entered into the NYC Response database. These samples, the majority of which were collected in Lower Manhattan and the Fresh Kills Landfill, were analyzed by a combination of Phase Contrast Microscopy (PCM), Transmission Electron Microscopy (TEM), and Polarized Light Microscopy (PLM). Other sampling locations are located in New Jersey and Brooklyn, NY. Sample media collected include bulk dust, ambient air, indoor air, and personal air monitoring (PAM) samples. In general, ambient air, indoor air, and PAM samples were analyzed by PCM to determine total fiber content in fibers per cubic centimeter (f/cc), and by TEM to determine the presence of asbestos fibers in structures per millimeter squared (S/mm^). Bulk samples were analyzed by PLM and are reported as percent asbestos (% Asbestos). It is important to note that PCM is a determination of total detectable fibers and can not be used to differentiate between, or identify, fiber type.

The following summaries and trend analyses, presented by media type, were developed from data available in the NYC Response database on November 9*'’ and do not take into consideration data entered since that time. The figures and tables in this report have been developed under the assumption that all data points (analytical results) reported in the database have already been adjusted for sample volume and other factors.

Ambient Air Samples:

Of the 4176 samples collected, 83%, or 3466, are ambient air samples collected in Lower Manhattan, New Jersey, and the Fresh Kills Landfill Between September 12* and November 2"'“. One thousand six hundred two (1602) of these ambient air samples were collected in Lower Manhattan (Locations A-V), 1301 were collected at the Fresh Kills Landfill, 190 were collected in New Jersey, and 373 were collected at various other locations in Manhattan. All of the samples were analyzed by PCM, with fibers detected at measurable concentrations in 891 samples from Lower Manhattan, 308 samples from the Fresh Kills Landfill, 8 samples from New Jersey, and 184 samples from other various Manhattan locations. Of these 1391 detected results, 526 were reported at concentrations greater than 0.01 f/cc and six (6) were reported at concentrations greater than 0.1 f/cc. After review of the available PCM data, several locations in both Lower Manhattan (Locations B, D, E & F) and the Fresh Kills Landfill (Location 09-A, 09-B & 12-A) were selected for trend analysis. The selection of these locations was based on the ratio of samples with reported detectable concentrations of fibers versus the total number of samples. Those locations exhibiting higher ratios were selected. The date collected and reported concentrations, along with the corresponding PM 2.5 results and average wind speed, are tabulated in Table 4. For those dates in which more than one sample was collected and analyzed for a given location, the higher of the reported results is used. PM 2.5 and average wind speed data are included in Table 4 and were added to determine if they had any bearing on fiber concentrations at the different locations. No correlating trends were observed. The highest results on a given day for the Fresh Kill Landfill locations (09-A, 09-B & 12-A) and the highest results on those days for the Lower Manhattan locations (B, D, E & F) were then plotted by date collected (x-axis) and f/cc (y-axis). The attempt here was to eliminate site-specific factors and show

Page 18 of 52

CITY_21MC100_002572235

NYC-WTC_000186212