MONTPELIER — Measuring the extent and cost of remediating contaminated soil is the next step of a proposed $10.5 million public parking garage in the Capital City.
The project calls for the removal of 4,300 tons of soil to bring the grade of the site on the Capitol Plaza Hotel down to match the grade of the adjoining Heney parking lot, where part of the garage will be built, according to project architect Greg Rabideau.
The garage is part of the Bashara family’s Hampton Inn & Suites franchise hotel and garage project behind the Capitol Plaza Hotel site on State Street.
Environmental studies have shown the site was contaminated over decades by motor oils, fuel oils and gasoline from leaking underground storage tanks, solvents from a dry-cleaning business, and building fires on the site. The city would be able to use Tax Incremental Financing funds to pay for soil remediation.
City officials said that testing of the site is expected to begin this week. The garage would be built on the most contaminated part of the site where the former Tavern Garage operated. Before buying the site in 1993, Fred Bashara II said he removed underground storage tanks, excavated about seven tons of soil from the site and sealed a floor drain used to pour oil into the North Branch river.
City Manager Bill Fraser said Wednesday the cost of remediation will not be known until all the environmental testing is completed.
“We have a pretty big number in our budget for environmental work,” Fraser said in an email.
Public Works Director Tom McArdle said it is not known how serious the contamination is, or whether it would require the removal of all the soil. McArdle said contaminated soils can sometimes remain on-site or be used as fill or at other project sites.
“I agree with Tom, we can often reuse the soil so there are no trucking costs,” Fraser added.
City officials were unable to say how much the cleanup might cost.
“Disposal runs into a lot of money; whether it runs into millions, I can’t say, and I don’t know if we have those cost estimates because the environmental assessment is still in progress,” McArdle said. “It’s a little early to say what it’s going to cost or whether all of it has to be disposed of.”
Rabideau said it’s possible the contaminated soil might be sent to the Coventry landfill and be used to cap part of the site.
Joe Fusco, vice president of communications for Casella Waste Management Systems, which operates the Coventry landfill site, was unable to provide precise figures for soil remediation costs in Vermont, saying costs vary depending on the level of contamination. But he provided a range of figures in the Northern New England region to estimate the cost, per ton.
Fusco said it would cost between $40 to $65 per ton to accept the waste, plus $40 to $50 per ton to transport it, and about $30 per ton as a tipping fee to the local solid waste management district.
Trish Coppolino, environmental project engineer with the Department of Environmental Conservation, agreed that soil remediation did not always mean it had to be taken off-site or landfilled. If it were heavily contaminated it would have to go to a hazardous waste site for special treatment that is more expensive, she said.
Asked whether soils contaminated with oils and fuels can be disposed on in a landfill, Coppolino replied: “Depending on contamination, yes. If the contaminants are above those standards, then they can’t go to a solid waste facility in the state. They would have to go to a hazardous waste receiving facility.”
Coppolino also said that some contaminated soils can be mixed with other materials to make them less hazardous.
Coppolino said it was not unusual for contaminated soils to be sent to landfills, such as the Coventry site.
The Coventry community recently protested a state permit for Casella to expand the landfill, despite the smell from the site and concern that it was contaminating Lake Memphremagog, used for drinking water on both sides of the U.S.-Canada border.
“For this specific project, or any other project, where soils meet certain standards — and they’re pretty low standards where there’s not a lot of contamination present in the soil — then the landfill can use it as alternate daily cover,” Coppolino said. “My role is to make sure that the (garage) site, when it’s cleaned up and reused, is in a manner that’s safe for a human environment.”
Coppolino said it was “not my role” to decide whether dumping contaminated soil in a landfill in another community was good environmental practice.
“I can’t stop that; it’s Casella’s business and it’s Casella that can say, ‘No we can’t take this much soil,’” Coppolino said. “Those aren’t things that I have a regulatory role in.
“I certainly promote trying to reuse as much material on-site and capping it in place and trying to take care of it with different mechanisms, such as parking lots and building foundations and long-term management of the soils in place,” she added.