Removal of material during demolition of concrete pad

National Grid’s Remediation Contractor continued with site remediation activities, which included the delivery of construction materials, imported backfill material (stone and common fill), and construction equipment and supplies. The Tent Position #2 Shallow Excavation and load-out remedial activities continued within the southern part of the temporary fabric enclosure as well as the off-site transport of impacted material to approved and permitted disposal facilities.  Operation of the Vapor Management System (VMS) at Tent Position # 2 continued and worker health and safety monitoring activities were conducted at the site, as necessary.  The placement and compaction of imported backfill material continued within the southern part of the Shallow Excavation Area at Tent Position #2.   Record of construction surveys and construction stake-out surveys continued as site remediation activities progress. 

Personnel and equipment decontamination pads were utilized throughout site operations.  Further delineation of work zones (i.e., exclusion, decontamination, and support) continued, as required. Maintenance of the on-site gravel access roads, parking areas and material staging areas, the imported backfill material (i.e., clean fill) stockpile covers, and the perimeter privacy screen continued.    Maintenance of engineering controls and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineer continued to monitor the site activities with the fixed base community air monitoring program (CAMP) equipment.

Decontamination of material removal truck prior to inspection

CAMP data is reviewed and compared to specific NYSDEC/NYSDOH approved criteria, known as “Action Limits.” As a result of this evaluation process, site conditions are categorized into two categories, “Operational Condition” and “Action Condition.” The “Operational Condition” is applicable when the data is below the “Action Limits”, and means that normal operations can continue. The “Action Condition” occurs when one or more of the fifteen minute average measurements for Dust (PM10), Total Volatile Organic Compounds (TVOC), Naphthalene or Odor Intensity are greater than the background or upwind measurement by the specified “Action Limits.” Reaching an Action Level requires corrective action or stopping work until the condition is addressed or abates. During the period from July 06, 2009 through July 12, 2009, six fixed base CAMP units and one portable CAMP unit were in-use and measured TVOC and PM10. Fifteen-minute averages for PM10 data remained in the Operational Condition; however elevated concentrations of TVOC were reported above the Site Specific Action Limit.

On July 8th and July 10th, CAMP Action Level exceedances related to the effect of the extreme rain and wind conditions on the tent were reported at one fixed base CAMP unit located directly south of the tent. Details on the exceedances are in the CAMP report. Corrective actions were undertaken to repair the tent and to mitigate against this situation occurring again. For both the July 8, 2009 and July 10, 2009 Action Level exceedances, National Grid notified the appropriate site operations personnel, NYSDEC officials, and Community Board 14 (CB-14) members.  The site remained in the Operational Condition (less than the Action Limit) on July 6, 2009, July 9, 2009, July 11, 2009 and July 12, 2009. Weekly Reports of the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of July 13, 2009 through July 17, 2009, Shallow Excavation Area remedial activities are scheduled to continue at Tent Position #2 with off-site transport and disposal of impacted soils at the approved and permitted disposal facilities. Delivery of imported clean backfill material (stone and common fill) will continue. Work zone delineation and maintenance of the on-site gravel access roads, truck lining and tarping stations, personal and equipment decontamination pads, and the truck scale will continue. National Grid’s consulting engineer will continue to monitor the site activities with noise and vibration monitoring equipment, as necessary. Maintenance of engineering controls and SESC measures will continue, as necessary.  Work zone air monitoring and VMS system inspection and performance monitoring will continue. Corrective action measures initiated within the tent during the previous week will continue throughout operations at Tent Position #2.  Odor and dust suppression activities will be conducted as necessary. National Grid’s consulting engineer will continue to monitor the site activities with CAMP equipment.