Con Edison Recommendations for MCSM Building Site Released

A new report detailing Con Edison’s analysis and recommendations for dealing with the toxic contaminants buried beneath our school building and grounds has just been released, along with a preliminary plan for long-term management of our site. You can now obtain copies of these documents for yourself from the Internet -- see the information at the end of this posting.

The new Analysis of Alternatives Report (AAR) contains six major recommendations for dealing with the contaminants left over from a former manufactured gas plant (MGP) that used to operate on our school building site from the late 1800s to the late 1930s:

1. Do not remove any of the coal tar from the holding tank or soil beneath the school building, since no cleanup technology exists that will remove most of the contaminants without suspending school operations for up to two years or demolishing the school building.

2. Since all indoor air tests to date have shown no harmful vapors entering the school from the contaminated soil beneath, install a sub-slab depressurization (vacuum) system underneath the basement floor to vent any harmful vapors rising through the soil to the outside air. The school’s concrete basement floor has already proven to be an effective barrier; this new vacuum-style system provides an extra level of protection for the children and their teachers.

3. Build an impermeable barrier along the eastern edge of the school property, alongside the FDR Drive, to prevent the contaminants that have migrated below ground in that direction from moving any farther toward the Harlem River. The barrier will prevent the contaminants from passing through, and a series of collection wells will trap and hold them for periodic removal.

4. Excavate and remove the toxic soil from the southeastern corner of the school yard (next to the FDR Drive and the basketball courts)and replace it with clean fill.

5. Leave the contaminants that have already migrated under the Harlem River bed in place and monitor them. At present, they do not appear to pose any threat to the fish or other biological entities in the river since they are 15-25 feet below the river bottom.

6. Implement management control and monitoring plans to ensure these systems operate correctly and effectively and that future excavation does not take place without proper precautions and controls.

These documents are available for downloading in both summary and detailed form by going to Con Edison’s website, www.coned.com/mgp, or you can click on the following: Con Edison AAR and CSMP Reports. MCSM’s reports are listed under “115th Street Site” (the first address tab on the left). The summary documents (Fact Sheet and Draft Decision Document are available in both English and Spanish). The Analysis of Alternatives (AAR) and Conceptual Site Management Plan (CSMP) are lengthy, detailed documents explaining the results of Con Edison's analysis (AAR) and their preliminary site management plans (CSMP) once their recommendations have been implemented.