DEP letter confirming completion of clean-up at 114 Liberty Street,

NYC 9/11 Public Portal Document

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Summary of the Analytical Results for the Chemicals of Potential Concern

USEPA's review of the analytical data for samples collected from 114 Liberty Street indicate that the areas sampled meet the numeric criteria established in the workplan (Table 1). The values chosen were established in the draft "World Trade Center Indoor Air Assessment: Selecting Contaminants of Potential Concern and Setting Health-Based Benchmarks" report (i.e., COPC document). The COPC document was created by a committee with representation from federal, state, and city government and was designed to establish numeric criteria to be used addressing potential contamination from dust and in

combustion by-products associated with the World Trade Center collapse and fire. This document is currently undergoing peer-review. The data which was evaluated consisted of air or wipe samples for six chemicals, asbestos, polycyclic aromatic hydrocarbons (PAHs), dioxin, lead, fibrous glass, at}d crystalline silica.

Table 1: Clearance Criteria rasedfor 114 Liberty Street Parameter Clearance Level Note Asbestos in air — PCMe 0.0009 s/cc Primary clearance level Lead in settled dust <25 ft2 Primary clearance level Dioxin in settled dust <4 ng/m2 Primary clearance level PAHs in settled dust <300 m 2 Primary clearance level Fibrous glass in air <0.01 f/cc Secondary clearance level Crystalline silica in air 1 m3 Secondary clearance level

Each area that was cleaned and sampled met the primary clearance levels identified in the work plan for asbestos, poiyayc4ic aromatic hydrocarbons (PAHs), dioxin, and lead. The secondary clearance level for fibrous glass has also been met in the areas that were cleaned and tested. The secondary clearance level for crystalline silica was met in 64% of the areas tested. The remaining areas were similar to background values observed from a USEPA background study. This is discussed in detail below. Since all of the primary clearance values have been met, the building can be released back to the owner.

There is one item that needs to be identified in relation to releasing the building to the owner, the area that contains the pizza shop. NYCDEP staff has indicated that the area of the building which contains the pizza shop contains asbestos-containing material (ACM). The ACM was considered to be in poor condition and the NYCDEP has indicated that an asbestos abate will need to be undertaken in this area. Therefore, this space within the building is not considered to have met the primary clearance value for asbestos.

Below is summary of the analytical results for each chemical. a

Asbestos — Eighty-eight air samples were collected before and/or during cleaning events. Four samples exceeded 0.0009 s/cc and four samples could not be analyzed due to the filters being overloaded with particulate matter. The before/during cleaning samples were not used to evaluate if additional cleaning was needed.

Seventy-one air samples were collected after first-cleaning event. Ten samples exceeded 0.0009 s/cc and eight samples could not be analyzed due to the filters being overloaded with particulate matter. Based on these results, there were five areas that required additional and-sampling for asbestos. These cleaning

areas were the 5', 7`", 8`h, 9`h, and 10th floors.

Twenty-five air samples were collected from the 5`h, 7d', 8'h, 9`h, and 10`h floors after the second-cleaning event. All samples were below the detection limit of 0.0004 s/cc and below the numeric criterion of

NYC-WTC 000102636