NYC-WTC_000233680

NYC 9/11 Public Portal Document

TRC Customer-Focused Solutions Corrective Action:

As a result of the roof abatement completion, samples were not collected on September 29, 2005 at air monitoring Stations 6, 7, 8, or 9. However, per ICR 56, the roof area was re-cleaned utilizing additional supplemental wet-methods and asbestos air monitoring reinstated on the roof for September 30, 2005 in order to confirm that concentrations were below the USEPA Site- Specific Trigger Level for Asbestos. Eive samples were collected, one on each roof corner and one in the roof center and analyzed for TEM EPA 40 CFR Part 763. No asbestos was detected in the five samples (< 15 s/mm^). These results are attached in the Supporting Data. Going forward, TRC will continue to closely monitor the use of dust control practices including frequently wetting surfaces containing dust with amended water during the work.

Supporting Data attached:

1. Analytical Data summary -analytical results for all stations on the date of the exceedance and the additional sampling which occurred on September 30, 2005. 2. Particulate Data - a. PM2.5 and PMw data for the sample collection period of interest at the station where the exceedance occurred b. plot of PMio concentrations (1 O-minute averages) versus time for the station where the exceedance occurred. 3. Meteorological Data - wind rose plot for the sample collection period of interest 4. Visual Inspection Reports - visible dust emission monitoring summaries from the 130 Liberty Street project. 5. Photographs of activities at and near the station where the exceedance occurred

Submitted By: Ed Gerdts Date: October 3. 2005

CITY_21MC100_0 07121523

NYC-WTC_000233681