NYC-WTC_000204863

NYC 9/11 Public Portal Document

11/08/01 FR] 16:46 FAI 51S 402 7819 NYSDOH-BTSA 121004

2. At 75 Park Place (upwind of the WTC site) and at 225 Rector (cross-wind), VOC levels, except ethanol, were generally in the range of levels commonly found in outdoor air samples (background). At 140 Broadway (downwind), where the smoke plume from the WTC site was visible during each of the sampling events, most of the VOCs were greater than background (generally less than five times background levels and all (except tTichlorofluoromcthanc) less than about ten times background levels).

3. Generally, VOC concentrations at 140 Broadway were about 3 times greater than those at Park Place and Recior Flace sites.

4. During each ot the sampling events, rhe smoke plume was visibly evident at 140 Broadway and bre odors were noticeable at the street level. During sampling at the other sites, the smoke plume was not visibly evident at the sites. WTC-related odors were sometimes noticed at the Rector Place site and not noticed at the Park Place site.

5 VOC cnncentratinn.s on the roofs were not substantially different from street-level VOC concentrations at each of tlie sampling sites, including 140 Broadway (53 stories high).

6- Concentrations of VOCs associated with the smoke plume were about 20 times greater in the grab sample at the pile tliua at 140 Broadway.

7. High levels of crichlorofluorotueiliaue (a rcirigcnuit, R-11), vvcic ubscivsd in the sampler fium the louf at 140 Broadway. The building manager said that a chiller leak senso" had detected a minor refrigerant leak ofR-11 on Friday (Sept ZS) morning. Theprobism was corrected later in the day, Ihs chiller is located on the 52nd floor and a mechanical room vent was about three meters (10 feet) from the sampler.

8. Elevated Tncihytcne chloride concentrations were also detected on Ilie roof of 140 Broadway with slightly higher levels found in the afternoon sample when the chiller was being repaired. Methylene chloride is commonly u-sed as a degreaser in building IIVAC (heating, ventilation and air conditioning) system maintenance and repair work. It was not measureable in the pliune sample or any of the other samples.

9. The field forms for the morning samples for 140 Broadway (roof and street level) were accidentally switched .so the laboratory report forma misidentified the rcof and arrcvt level suaiplcs at this locution.

10. Because the triclilorofuoromEthunc and methylene chloride were on the roof tup and people arc nut being directly exposed to tliem, they are not discussed in the health implications section.

11. Assuming that the fires and smoke will continue to diminish as the recovery work progresses, tliese data ■ suggest That additional VOC sampling for these compounds is not necessary. Kowever, it may be useful to confirm these findings, to assess levels of other volatile comppounds such as known respiratory irritants and to assess VOC concentration; once the fires arc controlled to ensure that other recovery activities are not a continuihig source of VOCs in the community.

Data Limitjaiions

These VOCs were selected .for onalyaia beccvise they ure commonly found ai low levels in outdoor and indoor air, routine analytical procedures were readily available ar.d many have been found in smoke. Other VOCs and scrnivolaLllc urgtmie cuiupuunds have been fuuud in the smoke fivni fios and can be c.n.(.'ccicd nesu' the site and in the smoke plume as well. Different sarapiing and analytical techniques are required for these compounds.

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