The city is working on an agreement with New Hampshire Department of Transportation to purchase 6.7 acres of state-owned land along the Connecticut River. The city has a conceptual plan for a 3-acre riverfront park that includes a recreation field and an extension of the trail network.

But first the parties must determine who will be environmentally liable for the property once the railyard changes ownership.

According to a tentative agreement reached last fall, the state would retain responsibility to remove existing hazardous contaminants, except for contamination caused by the city’s actions. The city would be responsible for future contamination of the property.

But in August, NHDOT Commissioner William Cass informed the city that it may be legally difficult for the state to retain environmental responsibility for land that it no longer owns.

“It is not as simple as the state agreeing to maintain all prior environmental liability as the city desires,” Cass explained in a letter to the city.

“Typically we would sell property ‘as is’ and value accordingly. It is very unusual to sell property and retain liability, and the Attorney General notes its hands are largely tied when agreeing to retain liability and potential future cost to the state.”

A city-funded environmental assessment of the railyard earlier this year found high concentrations of hazardous chemicals in the soil and groundwater, including arsenic and TPH (total petroleum hydrocarbons), a byproduct of diesel oil.

The study, conducted by engineering firm Credere Associates of Westbrook, Maine, recommends covering the contaminated soil at the park site with clean soil, asphalt or other “appropriate barriers” to prevent direct exposure to the contaminants. But should the federal government ever mandate a cleanup of the contamination, the liable party would have to shoulder those remediation costs, according to City Manager Shaun Mulholland.

“When the state offered to sell us the property, we said that we did not want to be responsible for the (environmental mitigation),” Mulholland said in a phone interview. “We were not going to assume those huge costs.”

The city had initially proposed leasing the land, so that the state would retain ownership responsibility.

But the parties later determined that leasing would not be feasible because it would restrict what Lebanon could build on the property, making the city’s plan for a park difficult.

According to NHDOT, the state Department of Environmental Services requested a retesting of soil and groundwater from the property. NHDOT contracted engineering consultant Stantec to collect that data, which has been sent to the Department of Environmental Services for review.

Once an agreement is finalized, several governing bodies will need to grant approval, including the City Council; the New Hampshire Council on Resources and Development; the Long-Range Capital Planning and Utilization Committee, a House legislative group; the Governor’s Office; and the Executive Council.

The city had hoped to construct the park shortly after the upcoming project to replace and widen what’s known as the Dry Bridge, a short span over railroad tracks, south of Seminary Hill, that is on the state’s red-list of bridges that are in poor condition.

Cass said the process is taking longer than usual because of the city’s request to keep the environmental liability under the state’s jurisdiction.

“We just need to do our due diligence,” Cass said.

— PATRICK ADRIAN/VALLEY NEWS