DEP response letter regarding cleanup scope, Apr 2003

NYC 9/11 Public Portal Document

during the (3) weeks. At least one asbestos supervisor shall be present per work area duration of the clean-up activities. Work shall be performed 24 hours per day, seven (7) days per week.

(5) Personal protective equipment including disposable clothing, gloves, and respirators shall be worn during this clean-up activity.

(6) Warning signs shall be posted at the approach to each work area.

(7) A separate worker and waste decontamination enclosure system in compliance with Title I5, Chapter I of the RCNY shall be installed at the entrance to each work area. Each work area shall entail isolating three floors at 125 Cedar Street simultaneously. More than one work area may be established. Work shall proceed from the penthouse down to the fi rst floor. The use of a remote decontamination enclosure system installed on the second floor for use at each work area (except first floor and basement) may be acceptable. Prior approval must be received from the NYC DEP for decontamination enclosure system placement and phasing of clean-up activities. (8) An entry/exit log in compliance with the requirements set forth in Title 15, Chapter 1 of the RCNY shall be maintained in the clean room. The site supervisor shall maintain an activity log. (9) Initially, the interior of the elevator shaft, including the top of the elevator car and the elevator pit, shall be HEPA vacuumed and wet wiped to allow for the use of the elevator during Inc clean up. Once the clean up throughout the building is complete, the elevator shaft, including the top of the elevator car and the elevator pit, shall be re-cleaned prior to clearance air monitoring. (I(J) Isolation barrier locations (i.e. : wall or ceiling penetrations, windows, vents, doors, etc.) shall be IIEPA vacuumed and wet wiped prior to installing two-layers of6-mil polyethylene sheeting and sealed with tape. Terraces, window wells, and window guards that are accessible from the interior shall be cleaned.

(l1) Negative pressure ventilation equipment shall be installed and operated continuously 24 hours per day during all clean-up activities. Equipment shall run continuously until clearance air monitoring. A minimum of one air change every 15 minutes shall be provided. When ducting to the outside is not possible, a second negative air unit compatible with the primary unit may be connected in series.

(12) A staging area shall be established within each unit. The area shall be cleaned (wet-wiped and HEPA vacuumed) and covered with a layer of 6-mu polyethylene sheeting. The staging area shall be used for cleaning the surfaces of moveable items.

(13) All debris and/or dust shall be misted and double bagged. Accumulation of water is prohibited Water misting shall be sufficient to wet the material without water accumulations. Caution shall be taken to avoid wetting items that may be damaged by wet methods. An encapsulating agent shall not be applied. Once all surfaces have been wet wiped and IILPA vacuumed a second cleaning shall be performed. Surfaces include but are not limited to walls, floors, ceilings, ledges, windowsills, trims, appliances, equipment, personal items, and furnishings.

2 of 7

NYC-WTC 000107173