Letter from EPA official to a Congressional representative criticizing the adequacy of the 114 Liberty Street cleanup.
NYC-WTC_000155264–000155285Folder label: “114 LIBERTY 2 OF 2”
OCR status: ok · source: pdftotext
NYC 9/11 Public Portal Document
13
EPA incorrectly compared silica levels with their background study EPA’s 4/18/03 report and cover letter to the residents excused the high silica levels found at 114 Liberty St. by claiming they were similar to its background study: The secondary clearance level for crystalline silica was met in 64% of the areas tested; however the remaining areas were similar to background values observed from a USEPA background study.
Silica - Eleven air samples were collected and analyzed for crystalline silica at a detection limit of 11 pg/m^ Seven samples were below the detection limit and four samples were above the detection limit, with values of 17.3, 19.6,22.1, and 22.1 pg/m®. ... Four out of eleven samples (36%) were above the detection limit of 11 pg/m®, ranging from 17.2 to 22.1 pg/m®. These values are also above the secondary clearance value.
Although these values are above the clearance value, they are similar to concentration detected in a background study conducted by USEPA In the USEPA background study, there was a frequency of detection of 25%, with a range of 4 to 259 pg/m®. Further, the values from the background study without the maximum value of 259 pg/m3, provide a range of 4 to 28 pg/m®. This indicates that the range of values observed in 114 Liberty Street are similar to those observed in the background study. Based on this, it has been determined that the crystalline silica results are similar to background values and therefore additional cleaning is not necessary.
This comparison by EPA is irresponsible. Comparing the ranges of values is irrelevant Looking at the distribution of values within the range, however, does provide a valid mechanism for comparison. The following is the more accurate way to compare the silica levels found by EPA at 114 Liberty with the EPA background study:
The average (arithmetic mean) concentration for silica in air at 114 Liberty was 11 pg/m®, which is 3 times the average level of 3.6 pg/m® found in the EPA background study. (The reason the 114 Liberty average concentration is right at the detection limit is because EPA always assumes that the actual value is only 16 of the detection limit for the “non-detect” samples. The average is thus the average of 7 values of 5.5 pg/m® (1/2 the detection limit of 11 pg/mj and 4 values at 17.3,19.6,22.1, and 22.1 pg/m®. See the references for an explanation of the calculations.’’)
Furthermore, the majority (76%) of the samples in EPA’s background study were below 4 pg/m^, which was the detection limit for the background study. However, only 64% of the samples at 114 Liberty were below a much higher detection limit of 11 pg/m®.
The table below provides the relevant levels found at 114 Liberty and in EPA’s background study: All the averages (arithmetic means) are calculated using the assumption in the EPA background study as well as EPA’s other WTC risk assessments that the actual value for any “non-detect” samples is 56 of the detection limit.
NYC-WTC_000155276
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NYC-WTC_000154976
Correspondence criticizing the EPA and DEP regarding asbestos, silica levels, and safety clearance after cleaning at 114 Liberty Street.
29 shared non-person entities · 1 shared topics · Same agency, volume and box · similarity 1.000
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000155286
Formal letter criticizing the EPA and DEP for alleged failures in cleaning asbestos and silica from 114 Liberty Street.
14 shared non-person entities · 1 shared topics · Same agency, volume and box · similarity 0.979
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000154652
Internal tracking document for managing reports, comments, and actions related to environmental compliance cases.
11 shared non-person entities · 1 shared topics · Same agency, volume and box · similarity 0.967
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000125845
Draft fact sheet from DOH and DEP addressing tenant concerns regarding asbestos fibers at 105 Duane Street.
18 shared non-person entities · 1 shared topics · similarity 0.973
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000140235
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15 shared non-person entities · 1 shared topics · similarity 0.967
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17 shared non-person entities · 1 shared topics · similarity 0.965
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000148115
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21 shared non-person entities · 1 shared topics · similarity 0.962
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000145345
Notice from NYC Law Department instructing staff to preserve World Trade Center documents for potential legal actions.
21 shared non-person entities · similarity 0.961
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000148952
Table listing volatile organic compound (VOC) sampling sites and dates outside of Ground Zero from September 2001 to January 2002.
23 shared non-person entities · 1 shared topics · similarity 0.960
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000145510
Notice from NYC Law Department instructing staff to preserve World Trade Center documents for potential legal actions.
21 shared non-person entities · similarity 0.960
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000145687
EPA report excerpt discussing the cessation of outdoor air monitoring in June 2002 and ongoing concerns about indoor contamination.
11 shared non-person entities · 1 shared topics · similarity 0.960
machine-extracted · confidence unavailable · Check page ↗NYC-WTC_000140138
EPA memorandum addressing World Trade Center asbestos contamination status and agency efforts to provide information on the situation.
11 shared non-person entities · 1 shared topics · similarity 0.960
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