Memo on media strategy for 125 Cedar Street, Dec 2002

NYC 9/11 Public Portal Document i NOU-12-2002 i6:-48.’" FROM US EPA R^SlON 2 ORC TO 317185954544 P.05/05 1

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Fibrous glass - We reviewed approximately 120 PCM results reported as fibrous glass analysis. The highest detected concentration was 0.009 f/cc, which is below the numeric criteria of 0.01 f/cc in the COPC document. Thus, for fibrous glass', the data we reviewed indicates that fibrous glass is not a hazard at 125 Cedar Street.

Mercury - We reviewed 66 wipe results which were analyzed for mercury. Seventeen samples were below the detection limit of 0.000478 /xg/'n? and the highest detected concentration was 0.0164 The COPC document does not establish a numeric criteria for mercury, however since USEPA is I collecting 250 wipe samples for mcrcuiy' as part of residential cleanup program a numeric criteria is I currently being developed. Tlie draft value, which is subject to revision based upon further evaluation of I exposure parameters, is currently 94 gg/h?. Comparison of the mercury concentrations detected to the draft numeric criteria of 94 gg/m” indicates that mercury is three orders of magnitude below the draft numeric criteria. Thus, for mercury, the'data we reviewed indicates that mercuiy is not a hazard at 125 ! Cedar Street. ~4.«v

I Silica - We reviewed the data for 19 air'samples which were analyzed for silica (i.e., total quartz). All of , the samples were below the detection limit of 10 gg. The numeric criterion that USEPA has proposed in the COPC document is 1 gg/n?. Although the COPC document has chosen the value of 1 gg/m‘’, the I available methodology for collecting indoor air samples for silica cannot achieve a value this low, therefore a result that is below the detection limit is considered to be protective of public health. This is the same approach we are u.sing at 110 Liberty Street, where the detection limit was 4 gg. Thus, for silica, the data we reviewed indicates that silica is not a hazard at 125 Cedar Street.

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