Project Description

Previous Investigative Activities

The site is currently divided into three parcels, identified as 222, 252, and 254 Maspeth Avenue, each under private ownership. The 222 and 254 Maspeth Avenue parcels are currently used for waste container fabrication and rehabilitation (222 Maspeth Avenue) or as a construction laydown yard (254 Maspeth Avenue). The 252 Maspeth Avenue parcel is used as a bus storage and maintenance yard.

The site and adjoining properties are heavily industrialized and have been the subjects of previous environmental assessments conducted by the current site owners. 

National Grid performed a remedial investigation (RI) at the Site during the period from September 2009 to May 2015 to identify sources of environmental impacts, delineate the associated extent of impacts, determine the surface and subsurface conditions in the area of the Site, and evaluate potential off-site migration pathways and their potential contributions to media and receptors.

During the RI, to date, two Interim Remedial Measures have been performed at the Site. The first, completed in September of 2012, removed shallow soils containing visible source material in a portion of the 254 Maspeth Avenue parcel where construction work was planned by the property owner. The second commenced in April 2013 and included installation of 23 recovery wells within and along the perimeter of the site to recover non-aqueous phase liquid (NAPL) present above the intermediate clay layer.

A Supplemental Site Investigation (SI) was conducted during August of 2018 to better characterize the nature and extent of potential impacts on the 222 Maspeth Avenue Parcel. Specifically, the SI was conducted to complete the investigation of subsurface soils within the 222 Maspeth Avenue parcel in proximity to a former gas holder.

In 2019, a Pre-Design Investigation (PDI) was completed to provide additional information to finalize the design of a third Interim Remedial Measure (IRM), which will occur on the 222 Maspeth Avenue parcel (see Upcoming Site Activities section below). Work consisted of the advancement of soil borings and the excavation of test pits as well as a structural inspection of the current infrastructure that may be effected by the planned IRM work.

In 2021, additional PDI activities were completed to support the IRM design for 222 Maspeth Avenue, including collection of additional In-Situ Solidification (ISS) treatability study mix design samples; collection of concrete samples for waste characterization testing; and pilot testing of recovery wells screened at selected intervals of deep, dense, non-aqueous phase liquid (DNAPL) below the gas holder foundation at 222 Maspeth Avenue.

The RI demonstrated that the extent of DNAPL is defined vertically and horizontally and there is no migration of NAPL beyond the RI Study Area, which included the former MGP site and the adjacent properties surrounding the former MGP site. No pathways for NAPL migration to the nearest surface water body, English Kills, were identified during the RI or subsequent investigations. Specifically, the horizontal extent of NAPL beneath the site is controlled by a depression in the primary confining unit, identified in the RI as the intermediate clay layer, which effectively contains NAPL to the former site boundary and immediately adjacent properties.

The findings collected during the SI and subsequent PDI work were consistent with the RI findings.  The SI and PDI further defined the extent of impacts documented during the RI within and adjacent to suspected former MGP structures beneath the 222 Maspeth Avenue parcel.  They show that the occurrence of NAPL beneath the 222 Maspeth Avenue parcel is controlled by the topography of the lower permeability units beneath the site.