Chain of custody form for DEP environmental samples, 2001

NYC 9/11 Public Portal Document

cleaned a second time using the same method as the original test. The unit was then tested again for the COPC that did not meet the health-based benchmark during the first test. If the unit failed to achieve the cleanup criteria again, it was cleaned with the strongest equipment (commercial quality vacuum with HEPA filter and an AFD). Midway through the project, the clearance criterion for lead was revised to use a health-based benchmark rather than a background level benchmark. This eliminated the need for re-cleaning some units, because the revised criterion indicated lead levels were lower than the newly established benchmark. For the most part, the health-based benchmarks were achieved after the first or second cleaning was completed. However, two units required three cleanings.

Air samples were collected to monitor for employee exposure during cleaning operations. Results are presented in Attachment A, Personal Monitoring Data.

1.6 The Work Plan

Specific procedures that were followed to perform the study, and a summary of all changes that were made to the work plan during the course of the study, are presented in Attachment B, TTie Work Plan and Changes to the Work Plan.

1.7 Project Documentation

At project commencement, digital photographs of all building interiors and building contents were taken. An inventory of personal belongings was developed. Photo documentation of the condition of each unit was compiled prior to each activity in the unit. Contents, conditions and specific areas of interest were digitally recorded. Photo documentation continued during initial sampling tasks. A record of equipment, materials, procedures and areas sampled was also maintained. Crews working in each unit were photographed. Procedures, equipment, and conditions were recorded during cleaning operations. All photographs were digitally recorded and are available upon request fi-om EPA.

9

NYC-WTC_000145707