Cleanup underway at NYSEG gas plant on Dansville’s Ossian Street

Staff Writer
The Dansville Online
Heavy machinery on hand for cleanup of the manufactured gas plant site located at 50 Ossian Street in Dansville.

DANSVILLE — Site action is underway to address contamination related to the former New York State Electric and Gas (NYSEG) manufactured gas plant (MGP) site located at 50 Ossian Street in Dansville under New York’s MGP Program.

NYSEG’s Dansville former manufactured gas plant site is located on a 2.25-acre parcel of land in the Village of Dansville. The site is mostly vacant other than a small active gas regulator station. Buildings on the site were razed in the summer of 2012. The site is flat with no significant topographic or geologic features. About three quarters of the site surface is covered with stone or paved, with the remaining portion covered with grass. The property comprising the former MGP site is zoned for commercial use.

The cleanup activities will be performed by NYSEG with oversight provided by the New York State Department of Environmental Conservation (NYSDEC).

Remedial activities began last week and are expected to last about three months. The estimated cost to implement the remedy is $350,000. The site is listed as a Class "2" site in the State Registry of Inactive Hazardous Waste Sites. A Class 2 site represents a significant threat to public health or the environment; action is required.

Access project documents online through the DEC info Locator:

Documents also are available at the Dansville Public Library at 200 Main Street.

Highlights of the cleanup activities

The goal of the cleanup action for the site is to achieve cleanup levels that protect public health and the environment. The key components of the remedy are:

— Remediation of groundwater by enhanced bioremediation. An oxygen releasing compound will be injected into groundwater to treat volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs).

— Groundwater monitoring using the existing monitoring well network to monitor MGP-related contaminants identified in groundwater at the site.

— Development and implementation of a Site Management Plan which will include:

• placement of an environmental easement on the NYSEG-owned property to restrict the use of the property, restrict the groundwater as a source of potable or process water and ensure implementation of the SiteManagement Plan;

• an excavation plan to manage future excavations;

• evaluation of the potential for soil vapor intrusion for future buildings developed on the site;

• an agreement with property owners to implement any necessary future site management plan on the off-site properties;

•preparation and submittal of a periodic certification of institutional controls to the NYSDEC;

• a Monitoring Plan to assess groundwater conditions at the site. A site-specific health and safety plan (HASP) and a Community Air Monitoring Plan (CAMP) will be implemented during remediation activities. The HASP and CAMP establish procedures to protect on-site workers and residents and includes required air monitoring as well as dust and odor suppression measures.

Remedial work addressing on-site contamination was previously completed between February 2013 and December 2015. It consisted of excavation of approximately 24,446 cubic yards of soil containing MGP-related contaminants, and backfilling excavation areas with 11,334 cubic yards of excavated materials that met re-use criteria and clean imported soil. Soil exceeding re-use criteria was transported off-site for thermal treatment, totaling 28,777 tons, or disposal, totaling 602 tons, at NYSDEC-approved facilities. A soil cover was placed over the excavation consisting of a minimum one foot of clean soil and underlain by a demarcation layer to prevent exposure to potentially impacted soil that remains.

Next steps

After NYSEG completes the cleanup activities, they will prepare a Final Engineering Report (FER) and submit it to NYSDEC. The FER will describe the cleanup activities completed and certify that cleanup requirements have been achieved or will be achieved. NYSDEC will keep the public informed throughout the cleanup of the site.

Additional site details, including environmental and health assessment summaries, are available on NYSDEC's Environmental Site Remediation Database (by entering the site ID, 826012) at: m?pageid=3

Summary of the investigation

The primary contaminants of concern at the site are volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) from the former MGP operations, which exceeded water quality standards in groundwater monitoring wells downgradient from the site northwest across Battle Street and Franklin Street. Observations of MGP material during the investigation of the site were limited to trace amounts of coal tar extending from the site northwest to Franklin Street. The coal tar was observed at thicknesses of two feet or less, ranging at depths from 11 to 17 feet below ground surface.

Manufactured Gas Plant (MGP) Program

New York's MGP Program oversees the investigation and cleanup of former manufactured gas plants. The gas manufacturing process involved the heating of coal and/or petroleum products to produce a gas mixture. Once cooled and purified, the gas was distributed through a local pipeline network. The gas was used for heating and cooking in much the same way that natural gas is used today. In the early years, the gas was also used for lighting in homes and streetlights. For more information about the MGPs, visit:

A wide view of 50 Ossian Street in Dansville, site of the contamination cleanup.