The U.S. Environmental Protection Agency has a cleanup plan for the Superfund site near the Susquehanna River in Columbia.

Essentially, time and Mother Nature will do the work from this point forward, and the EPA will monitor their progress at the former UGI Columbia Gas Co. property on Front Street, according to a "record of decision" approved by James J. Burke, director of the EPA's hazardous site cleanup division for Region 3, which includes Pennsylvania.

The record of decision spells out EPA's remediation plans for the property.

"There is no immediate threat to human health or the environment," said Bill Hudson, EPA's community involvement coordinator.

UGI Columbia manufactured gas on the 1.6-acre property from 1853 to 1960.

During that period, many contaminants, including cyanide, polluted the soil and groundwater on and around the property, according to the EPA.

Also, large amounts of tar, generated as a byproduct, leaked into the ground and into the bed of the Susquehanna River.

PPL Electric Utilities now owns the property, which has been a priority on EPA's list of Superfund hazardous-waste sites since 1994. The federal Superfund program was created to help clean toxic waste sites.

In the late 1990s, as part of the cleanup of the site, hundreds of tons of tar were dug out of the ground and dredged from the bottom of the Susquehanna River, hauled away and incinerated.

Contaminated soil on the property is encapsulated under pavement and is considered to be under control as long as the pavement remains.

The groundwater contamination is located deep underground in fractures in the bedrock.

Hudson said it's virtually impossible to extract the contaminated water from those crevices, so time and the natural flow of water are expected to gradually flush out the pollutants.

The contaminants will be flushed into the Susquehanna River, Hudson said, but they will be so diluted they are not expected to cause any environmental or human health problems.

EPA will continue to monitor the groundwater to track the flushing of the contaminants.

No drinking water is drawn from the ground in the vicinity of the former UGI Columbia property, and no wells will be permitted to be dug there.

PPL and UGI will be required to obtain easements from the owners of neighboring properties — Columbia Borough, the Pennsylvania Department of Transportation, Pennsylvania Lines and Lancaster Water Authority — which will prohibit building homes, digging wells and using groundwater on their properties, according to the record of decision.

The full text of the record of decision can be viewed online at www.epa.gov/arweb.

E-mail: preilly@lnpnews.com