NYSDEC letter re: Con-Edison release report at 7 WTC substation,

NYC 9/11 Public Portal Document Fax •• Nov 9 1599 13:14 bOV 21 ’01 06--01PI*. R & D P.3

subsurface investigation work plan 7 WORLD TRADE CENTER

im'RODUCTION

As a result of the catastrophic events caused by the September 11,2001 terrorist attack on the World Trade Center, including the collapse of 7 World Trade Center (7WTC), Con Edison has reported the release of approximately 100,000 gallons of transformer oil and dielectric fluid from its former, jd^trie dietribution substation located. within that bufidi^. In addition, it appears that significant amounts of petroleum products belonging^ to other entities were also released to the environment as a result of those events. The site of the former 7WTC building is bounded by Barclay Street on the north, Washington Street on the west, West Broadway on the east, and Vesey Street on the soutb.

Con Edison has prepared this subsurface investigation work plan at the direction of the New York State Department of Environmental Conservation (NYSDEC). The purpose of this investigation is to locate petroleum free phase product within the perimeter of the former 7WTC building, so that, the oil can be recovered and its migration, if occurring, can be controlled.

SCOPE

Con Edison will install up to seven 6-inch diameter groundwater monitoring wells to a depth of approximately 25 feet below ground. Those wells, in conjunction with the trenches being excavated by Verizon along Barclay and Washington Streets, will be used to identify where petroleum free product may exist and to determine whether there ia any on-going migration.

Groundwater samples will be collected from the Verizon trenches being excavated along Barclay and Washington Streets. Groundwater monitoring walls will be installed in the trenches prior to their backfilling if free product is evident at that time.

A comprehensive survey of all accessible Con Edison manholes inside the 7WTC footprint and within the immediate vicinity will be conducted to determine the severity of impact and opfimal recovery locations. Con Edison assumes that the NYSDEC will coordinate similar inspections of underground structures belonging to other entities in the same area and will arrange to have the results of those inspections provided to Con Edison to enhance the value of this survey.

A visual inspection of the subgrade parking area off Ramp J will be conducted to verify, if possible, the intersection of the ’hub wall" with the tetaining wall (sec Rationale below). This inspection is contingent upon the receipt of permission from the New York City Department of Design and Construction (DDC).

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