NYC-WTC_000209427

NYC 9/11 Public Portal Document

Table 3. ATSDR AIR LEVEL FINDINGS COMPARED TO LEVEL CHOSEN BY REGION 1

Background ambient air levels are from studies determined to be the most credible by the ATSDR®*

Concentration in TEM Equivalent concentration in strictures per milliliter PCM fibers per milliliter (s/mL). This includes all (PCM f/mL). PCM fibers asbestos fibers and are only those single fibers bundles of fibers, and so which are longer than 5 is higher than “PCM" micrometers with a certain fibers. aspect ratio.

expressed as expressed as exponential exponential

ATSDR finding: outside air, rural, no 0.00001 (1 X 10-®) 0.0000002 (2 x 10-®) known source of asbestos contamination nearby

ATSDR finding: outside air, urban, no 0.0001 (1 X 10-^) 0.000002 (2 X 10'®) know source of asbestos contamination nearby

ATSDR finding: 1988 EPA survey of 94 0.006 (6 X 10 ®) 0.0001 (1 X 10'’) public buildings containing asbestos materials, mean concentration

ATSDR finding: 1988 EPA survey of 41 0.03 (3 X 10 ®) 0.005 (5 X 10-*) schools containing asbestos materials, mean concentration

AHERA TEM clearance test level, the “70 0.02 (2 X 10'®) 0.01 (1x10-®) structures per square centimeter” level, approximately converted to s/ml. and PCM equivalent f/mL. This is an unsafe level for long term exposures.®®

Region 1 level for background outside air, 0.045 (4.5 X 10 ®) unknown used for risk assessment

Region 1 failed to use real-world background dust levels

There was no reason for Region 1 to have gone through any calculation process to project background dust levels from air levels. Typica l background dust levels are well established, just like typical air levels.

Region 1 chose to ignore the fact that the same reference®® they used for K-factors also contained real world data for typical dust levels, which ai'e widely recognized by industrial hygienists and other asbestos abatement specialists. See Table 2 for typical dust levels for buildings with or without asbestos contamination problems. Compare 200 s/cm®, a real world background level for buildings that do not contain asbestos materials, with Region I's calculated level of 45,000 s/cm®.

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