About Bay Shore Former MGP Site

The Bay Shore former MGP Site

Significant progress has been made in the cleanup of the former Manufactured Gas Plant (MGP) site in Bay Shore and the gas operations support facility in Brightwaters. The project is entering its final phase. National Grid will continue to lead remediation efforts until the New York State Department of Environmental Conservation (NYSDEC) determines that the work is done.

The most recent remediation measures in the Bay Shore/Brightwaters cleanup took place in OU-1 and OU-3 beginning in June 2015. The work was completed under New York State Department of Environmental Conservation (NYSDEC) approved work plans submitted by National Grid to address remaining shallow impacted groundwater. National Grid upgraded the 87 Community Road oxygen injection line and expanded the OU-1 South oxygen injection line across N. Clinton Avenue.


In January 2003, as part of the final remedial investigation report prepared by Dvirka and Bartilucci, a consultant for KeySpan, four operable units (OUs 1-4) were identified for cleanup, each with its own unique environmental conditions and remedial objectives:

  • OU-1 constitutes the main site area - the Bay Shore West Parcel and an adjacent offsite area to the south of the Long Island Rail Road (LIRR). The portion of the area to the north of the LIRR is the area where the main operations of the MGP took place.
  • OU-2 is a groundwater plume, originally about 500 feet wide, extending from the Bay Shore side of the site southwest toward Lawrence Creek.
  • OU-3 includes the Brightwaters Yard gas operations support facility and a second groundwater plume originating from the Brightwaters Yard, originally about 100 feet wide and extending south in the direction of O-Co-Nee Pond.
  • OU-4 is east of OU-1, where former treated process waters were discharged. The area is beneath and around the current Bay Shore LIRR station town of Islip parking lot and includes several privately owned properties, as well as the headwaters for Watchogue Creek, historically known as Crum's Brook.

While the remedial investigation (RI) found no evidence of impact to the communities' drinking water supply, MGP and feedstock-related contaminants were found in each of the OUs, with the potential for exposure to the community and wildlife. These contaminants - which can be found in byproducts of the manufactured gas process, like coal tar - include volatile aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAHs).

NYSDEC approved National Grid's RI in 2003. NYSDEC-approved remediation activities at the former MGP site have been underway dating back to 2000, even before the RI was conducted, and are yielding excellent results. As each step of the remediation phase is finalized, it moves into a phase of ongoing maintenance and monitoring.

Visit NYSDEC's Manufactured Gas Plant Site program page for more information.

Operable Units

Operable Units Map

Click on the image above to view an enlarged map of the Operable Units.

Read more about MGP waste materials and their associated contaminants.