UGI Columbia Gas Plant

Overview

Coal gas was made at this 1.5-acre site in Columbia, Pennsylvania from 1851 to 1949. That process left behind coal tar, polyaromatic hydrocarbons (PAHs), volatile organic compounds, heavy metals, and cyanide in the soil, bedrock, groundwater, and sediments of the nearby Susquehanna River. The site was added to EPA's National Priorities List (NPL) in May 1994, making it a federally designated Superfund site requiring cleanup.

The responsible parties, Pennsylvania Power and Light and UGI Utilities, carried out the main physical cleanup between 2006 and 2007. They excavated contaminated soils and installed concrete and asphalt caps over remaining contaminated material. EPA approved a final cleanup plan in September 2007. That plan required no additional soil removal but called for long-term groundwater monitoring, cap maintenance, and institutional controls. A groundwater monitoring plan was approved in June 2011. In June 2018, EPA modified the cleanup by expanding the area where restoring groundwater to drinking-water standards is not practicable and adjusting which contaminants require ongoing monitoring. The site reached "sitewide ready for anticipated reuse" status in 2018. Columbia Borough currently uses the property as a vehicle maintenance garage and road salt storage facility.

Twenty-six contaminants of concern have been identified at the site. They include benzene, toluene, and other volatile organic compounds, heavy metals such as lead, barium, and manganese, and PAHs such as benzo[a]pyrene, naphthalene, and pyrene. These substances were found in groundwater, sediment, soil, and coal tar deposits. The caps prevent direct contact with contaminated soil, and no current exposure to contaminated groundwater is occurring. Contaminated groundwater is stabilized in its original area and shows no unacceptable discharge to surface water. Institutional controls restrict groundwater use, prohibit soil excavation, and prevent residential development.

EPA completed a five-year review in May 2021, concluding the remedy protects human health and the environment. The review recommended further evaluation of institutional controls and groundwater monitoring for ecological risk. Another five-year review is estimated between May and July 2026. The site has not yet been deleted from the NPL.

Community members with questions about the site or the upcoming five-year review can contact EPA's Community Involvement Coordinator or Remedial Project Manager. Administrative records are available for review online or in person at the Mountville Public Library in Mountville, Pennsylvania, or at the EPA Region 3 office in Philadelphia.