Manufactured Gas Plant FAQ

Our investigations evaluate actual and potential risks to the public through exposure to contaminants from these facilities. Exposure to contaminants can potentially occur through direct contact with the waste or through gas contaminants getting into indoor air. Our indoor air sampling results have not found any impacts to indoor air quality. Exposure to contaminated groundwater through ingestion is not expected because the areas around these sites are served by municipal water systems. Because these sites have been closed for many years, and, in most cases redeveloped, we do not anticipate exposures to be significant. Much of the waste or contaminated soil will not be at the surface where direct contact exposure may occur. Con Edison and agency staff prepared a soil gas/indoor air survey work plan that will be used at sites where testing is warranted.

There are dozens of materials potentially associated with former plant sites. These materials could include coal, slag, ash, cinders, coal tar, oils, and, gas purification wastes; and contain benzene, toluene, ethylbenzene, xylene, creosote, polycyclic aromatic hydrocarbons (PAHs), and cresols, among others.

The New York State Department of Environmental Conservation and other experts have indicated that the substances most frequently found are coal tar and gas purification wastes, and their associated byproducts: coke, naphthalene, benzene, and PAHs.

No. Both the New York State Department of Environmental Conservation and Department of Health helped develop and approve the work plans and protocols already being implemented by Con Edison to identify and address potential impact at former manufactured gas plant sites. The state agencies prefer that owners work in cooperation with Con Edison to follow the approved work plan.

Each site was evaluated and handled on a case-by-case basis, with public health and safety being our first priority. The following steps have been or will be taken:

1. On-Site Inspection: We arranged a site visit with environmental scientists and/or engineers. We looked at the layout of any buildings on your site and outdoor areas to identify possible locations for conducting sampling during future studies.
2. Indoor Air Screening: We collected soil vapor samples by creating a few small holes in your basement floor, and monitored the air inside your building.
3. Subsurface Investigation: We checked the presence and extent of contamination in your soil and groundwater and may have installed one or more wells to monitor your groundwater.
4. Remediation: If we find contamination related to a manufactured gas plant on your property, the New York State Department of Environmental Conservation, with input from the New York State Department of Health, will develop a remediation work plan.