EPA letter on residential dust cleaning results, Jan 2003

NYC 9/11 Public Portal Document

Confirmation #: 0021010623 "Asbestos Air Sampling Results for 45 Wall Street^ r Laboratory: EMSL ‘ Pll ' OaU Validation Date: 10/28/2002 * Transmission Electron Mcroscopy (TEM) Analysis with Phase Contrast Microscopy Equivalent (PCMe) Counfing Method - Ste^iw'met*M<^/deter^ni^mir^l^e^«rite^ C^^pSora'r&fe^*^^hteatuiAdminb^tion(Oa?A')^ndaS''j^wrke%'ofO^l'IbS/cubte'centirriterof^^ Description of Metnod:

sample Locauon Dale Wea I4uii-Asue!>ius Asbesujs ------- Anaytimi------- /tMJBsius! cuimiiraiiuii Analyzed (sqmm) Fibers Type Tbers>5um Sensitivity (fibers/cc) (fibers/cc)

10623-297-1511 Living Room 10/24/02 3,712.5 0.2000 so Not Detected 0.0 0.0005 <0.0005 10623-297-1512 Dining Room 10/24/02 3,6938 0.2000 To Not Detected oo" 0.0005 <0.0005 10623-297-1513 Kitchen 10/24/02 3,712.5 Not Analyzed oT 10823-297-1514 Bedroom 10/24/02 3,693.8 0.2000 0.0 Not Detected 0.0005 <0.0005 10623-297-1515 Bathroom 10/24/02 3,7125 Not Analyzed To 10623-297-1516 KHchena 10/24/02 3,731.3 0.2000 8.0 Not Detected To 0.0005 <0.0005 Key: Sample Identification number assigned to the sample. Location Location in the apartment where the sample was collected. Date Date the sample was collected. Volume (L) Volume of air drawn across the filter in liters. Area Analyzed (sq.mm) /Vea of the filter which was analyzed in square milimeters. Non-Asbestos Fibers Number of non-asbestos fibers which were detected. Other fibers types include fibrous glass, mineral wool, cellulose and fabric fibers. Asbestos Type Type of asbestos detected. Types indude chry sotle, croddollte, amosite, anthophyliite, tremolite, or actinolite. Overload indicates that a sample could not be analyzed because mae than 25% cf the filter contained excess particulate matter. Asbestos Fibers > 5 urn Number of asbestos fibers detected greater than (>) 5 microns in length. Analytical Sensitivity (fibers/cc) Lowest value the analytical method can detect. This value is below the clearance criteria of 0.0009 f/cc. Asbestos Concentration (fibers/cc) Estimated number of asbestos fibers greater than 5 microns detected per cubic centimeter of air. This is the value that is compared to the health-based clearance criteria of

The last column of the table above, labeled Asbestos Concentration (fibers/cc), contains the data which was compared to the health-based clearance criteria of 0.0009 f/cc. The health-based clearance criteria represents an asbestos concentration in air that is associated with negligtole adverse health effects over a 30-year exposure period. Sampling results which are equal to or below this value are considered to meet the deaiance criteria. Sampling results which are above this value are considered to exceed the clearance criteria and wBI result in a recommendation to clean and test the apartment again. If one or more sample is overloaded, it will be recommended to clean and test the apartment again, if a sample is reported to be less than (<) the analytical sensitivity it means that not only are you below the health-based clearance criteria, but you are also below the detection limit for the method.

In addition to the analysis of the samples using the TEM PCMe counting method for determining if the clearance criteria was met two additional analyses were done to provide additional data. The second is similar to the TEM PCMe counfing method with the exception that ail asbestos filers greater than (>) 0.5 microns are counted. Although the scientific data indicates that the long fibers (greater than 5 microns in length) are the most important from a long-term health perspective, the standard protocol for determing asbestos cleanup for schools counts asbestos fibers greater than 0.5 microns. For comparison, we collected this information also. The third analytical method, PCM, counts all fibers, which include asbestos, fibrous glass, mineral wool, cellulose and fabric fibers, greater than (>) 5 microns. As there was a significant amount of fibrous glass associated with the World Trade Center collapse, we also wanted to provide data on total filers. In general, if the TEM PCMe and the TEM analyses indicated that one or a few asbestos fiber the other fibers as detected by the PCM measurement are fibrous glass, mineral wool, cellulose or fabric fibers. The results of these analyses are listed on the next page.

NYC-WTC_000150146