NYC Law Department letter regarding EPA draft report excerpts, July

NYC 9/11 Public Portal Document

Final Technical Report of the Public Health Investigation Page 32 of56 dust, In either Indoor or outdoor areas of lower Manhattan.

2. Association of Asbestos and Synthetic Vitreous Fiber Levels Outside of and Within a Building

Outdoor settled surface dust was collected at 14 buildings In lower Manhattan. One purpose for collecting outdoor dust was to determine if the contents of the outdoor dust at a location would reflect the type of Indoor dust. In the case of fibers, there Is little correlation In the Indoor and outdoor dust composition. High levels of outdoor SVF are associated with both high and low Indoor levels. The presence or absence of asbestos In settled surface dust · shows a similar lack of correlation. The outdoor settled surface dust samples do not correspond with Indoor dust composition for either group of fibers. This lack of association could, In part, be . due to whether and how frequent interiors and exteriors had been cleaned.

In contrast, Indoor levels of fibers in settled surface dust did seem to correspond within a building. Buildings with elevated SVF levels In the common area tended to have elevated levels In the residences. A similar pattern was seen between the two residences sampled In the same building. For example, SVF was often found In both residences sampled within the same building, or was absent In both residences. Within this limited data set, fiber levels In one area of a building seem to weakly correspond with fiber levels In other areas of the same building. However, none of these data represent total dust loading, only the relative amount of fibers within the dust.

3. Occurrence of Crystalline Minerals

Indoor areas that have elevated levels of quartz In settled surface dust appear to also have elevated levels of calcite, portlandlte, and gypsum(see Figure 10). Additionally, these four minerals appear together In all outdoor samples with only minor exceptions. Although only 14 of the 30 buildings had samples taken of outdoor dust, there does seem to be a correlation between elevated outdoor and Indoor levels of quartz, gypsum, and the other minerals. It Is unknown If this would be seen In outdoor areas above 59th Street for comparison, as not enough outdoor dust was available for analysis.

Most elevated quartz and gypsum levels Indoors were found In the first ten buildings sampled during the first 5 days of the project (with the exception of 14% quartz In the common area of building 22). Although many of these buildings were closer to the WTC site, location may not be the only factor contributing to higher mineral levels In the dust. Other buildings sampled in these areas later (e.g., 13, 14, and 28) did not have elevated levels of minerals. Many factors may contribute to this finding Including whether the area was cleaned (indoors, outdoors), the cleaning method used, the time since the last cleaning, and the amount of dust that was Initially In the area. It Is not clear which factors contributed to variation In mineral levels by building.

Within a building, levels of quartz, calcite, and portlandlte tended

http://www.atsdr.cdc.gov/asbestos/lowermanhattan/ResSamp_Sep2002_Text.html 07/18/2003 NYC-WTC_000146692