World Trade Center asbestos situation memorandum, December 2001

NYC 9/11 Public Portal Document

ATSDR’s findings are given in Table 3, along with asbestos levels found in buildings with and without asbestos contamination problems. The level for rural areas is 0.00001 s/mL, and urban air is 0.0001 s/mL.^’ (These levels would be the equivalent of 0.0000002 PCM f/mL and 0.000002 PCM f/mL.) Compare 0.00001 s/mL and 0.0001 s/mL with the level of 0.045 s/mL used by Region 1 for the Brookfield schools!

This 0.045 s/mL level is not a safe level, much less a background level. It is even higher than EPA found for air inside of 41 schools where there was an asbestos contamination problem (0.03 s/mL). It is also more than 2 times higher than the AHERA TEM air clearance test level of 70 structures/square millimeter (which is the same as 0.02 s/mL, or about 0.01 f/mL-PCM), which itself is not a safety level.’® See Appendix B of this memorandum for the cancer risks associated with different air asbestos levels.

Region 1 also falsely claimed that 0.01 to 0.045 s/mL asbestos in air is the EPA benchmark for ambient air.” The fact is, EPA has no benchmark or ambient air standard for asbestos. This is made clear in EPA statutes, regulations, and publications.’^ As stated earlier, EPA does not consider any exposure level to asbestos to be safe. The only benchmark is zero asbestos levels, zero exposure.

Region 1 chose an inapplicable K-factor to Justify a higher dust level

Region 1 needed to do more than use an incorrect value for background air in order to make its risk level for settled dust high enough to cover existing contamination levels in the Brookfield School System. To do this. Region 1 also intentionally chose an inappropriate, low K-factor for its calculations. The study used by Region 1 for K-factors had data for 6 different controlled, real world situations. See the endnotes/references for a table of all the K-factors from this study.’’ Region 1 chose the K-factor at the 10^ level (0.000001) associated with cleaning a storage area and cleaning a carpet with a conventional vacuum cleaner. However, there were two activities which were much more likely to be associated with a school, namely gymnastic activities and cleaning with a broom, where the K-fector was at the IO"’ level (0.00001). Region 1 chose to ignore this more applicable K-factor, because it would have resulted in a dust benchmark 10 times lower! See Table 4.

Because of the uncertainty of the data in the K-factor study, Region 1 also should have allowed for a large margin of error, or should at least have used the average for all six K-factors. If it had used the average of the six, then the K-factor would have been lO"^, or 0.000001. This would make dust benchmark 100 times lower! See Table 4.

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