NYC-WTC_000205042

NYC 9/11 Public Portal Document

104 East 2Sth St.. 10th Floor Mew York. New York 10010 WWW,ate-enviro.com 212.353.8280 Fax 212.353.8306 ASSOCIATES INC.

July 2, 2002 Cole Environmental Technologies 22S9 Saw Mill River Road - Bldg. 5 Elmsford, NY 10523 Attn: Mr. Akin A. Cole Re: Interpretation of Microvac Results Dear Mr. Cole: Regarding interpretation of the results of transmission electron microscopy (TEM) analysis of microvac samples from Fire Department of New York vehicles, it should be mentioned that there are several methods which may be used to sample settled dust. However, there is no official EPA policy on dust sampling and analysis, no official method, and there are no laboratories accredited to perform these analyses. Consequently, there is no accepted threshold value for asbestos concentrations in settled dust. However, in a December 19, 2001 memorandum published by the ERA, it states that industrial hygienists and other health professionals recommend professional abatement procedures when a microvacuum sample exceeds the detection limit (analytical sensitivity), or background, of over 1000 asbestos structures per cm’. Since, I believe, all of the FDNY vehicles that were sampled analyzed below 1000 asbestos structures per cm’, they did not require any abatement procedure. It should be noted that some labs suggest the following guidelines: <1000 asbestos structures per cm^ = 0 H 1000-10,000 asbestos stzructures per cm^' = background levels 10,000-100,000 asbestos structures per cm’ = moderate levels >100,000 asbestos structures per cm’ = high levels H but these are based on subjective interpretations and have no clinical or legal justification since it would require some (likely variable) activity to resuspend asbestos containing dusts. H I hope this communication has been of some help. Please contact me if you have any questions.

Very truly yours, ! ba

'Michael A. Gorycki, Ph.D. Director of Electron Microscopy Ur

I b I b CITY_21MC1OO_O12359488

NYC-WTC_000205042