NYC-WTC_000195194

NYC 9/11 Public Portal Document

w Another issue which impacted EPA’s data reporting was the rejection of data during the <«r validation process. Several wipe samples and one air sample that were analyzed for dioxin/furans w were initially reported as rejected. Fortunately, the rejected dioxin/furans data could still be utilized to obtain a Toxicity Equivalent value by calculating an Estimated Maximum Possible W' Concentration (EMPC) for the dioxin/furans that were rejected. In addition to the dioxin/furans, several lead samples (air, wipe and micro vacuum) were rejected for lab blank, field blank or method blank contamination. The only other sample that was rejected was an inorganic wipe sample that was rejected due to a laboratory blank being out of the control range. w The wipe sampling analytical results for alpha-quartz, calcite, gypsum, cristobalite, tridymite, and total dust were uncertain, thereby rendering the data unusable.

3.9 Modifications to the Study

Modified Aggressive Air Sampling Both modified-aggressive and aggressive air sampling were used in determining if asbestos air clearance criteria could be achieved in four units. The use of modified-aggressive air sampling was included after repeated problems with overloaded filters were encountered and the further evaluation of aggressive sampling determined that conditions created by aggressive air sampling were not typical of household living patterns.

m?/ Wipe using Windex'^/Wipe with Water Only The work plan initially called for use of soap and water to accomplish wet wiping. Windex® brand was used because it is a commonly used cleaner believed to be readily available in most people’s homes. Furthermore, it is non-damaging to most surfaces, from wood to fiberglass. Typically, this soap does not “over-suds”. It provides an effective detergent-based protection of surfaces when combined with cold water. This was important, because hot water was not immediately available at the project site. During the project, it was determined that a wet wipe procedure using water only would also be evaluated. Water only was used on the desktop and in the bathroom of the Chiropractor’s Office, and in the entire Barber Shop. Water only was also used on the vinyl tiles under the carpeted area in the Mattress Showroom.

Horizontal Wet Wipe Only/Horizontal and Vertical Wet Wipe The majority of the tests of cleaning methods were accomplished using horizontal wet wipe only, to assist in determination of whether vacuuming without wet wiping would result in acceptable cleaning. However, application of both horizontal and vertical wet wipe was tested in Units 3B and 3C. Application of both horizontal and vertical wet wiping in Unit 3B was consistent with the procedures called for relative to testing of Scope A - Lower Manhattan Cleaning Procedures. Unit 3C was selected for an additional test using both horizontal and vertical wet wiping, because that apartment was heavily impacted by WTC dust. The cleaning test called for the use of non- HEPA-filtered vacuums and no AFD.

Use of Swiffer Brand Cloths The use of Swiffer® brand cloths for application of wet wipe was also evaluated. Swiffer® cloths were utilized during the cleaning of the first residential unit 5D.

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