Some city leaders are losing patience with the lack of movement — and payment of taxes — regarding the 21.5-acre former Kingsbury Corp. property off Marlboro Street.

The site has been all but vacant since 2011, when the company filed for bankruptcy. Two years later, as the city mulled taking the property in lieu of unpaid taxes, a Manchester businessman bought the site for $50,000. Since then, he’s leased out two small areas for storage, while playing a game of cat and mouse with the city over taxes — paying just enough, just often enough, to stave off legal action.

That’s not an unheard of situation for a municipality. Often, large taxpayers (and even small ones) will use such a strategy which, while maddening, is within the law. More problematic for Keene is that the owner, Brian Thibeault, appears not to have any concrete plans for the property, yet is holding up any future use for the site. It’s a key piece of both the Marlboro Street corridor and the East Side/Beaver Brook area.

Complicating everything are two environmental factors.

First, the brook actually runs through the site and under the building at one point, hindering the city’s efforts to mitigate flooding along the East Side. One possible future for the site, if the city owned it, would include creating a flood retention area there.

Second, Kingsbury was a manufacturing plant, creating metal toys and, later, machine tooling machines, and there are real concerns about contamination on the site. PCB contamination was addressed decades ago, but apparently remains an issue, as are several underground tanks that may have been used for fuel or as disposal sites, and which may have leaked or leached contaminants into the groundwater and soil.

Because of this latter concern, the city undertook an environmental study a year ago, using a $200,000 federal grant. The initial assessment recommended more study, which Thibeault has not agreed to yet.

Last month, Councilors Mitch Greenwald, Janis Manwaring and Dave Richards argued it’s time for the city to start the process of taking the property. Thibeault owes nearly $1 million in taxes and interest at this point, though the bulk of that — about $670,000 — is from before he bought the site.

Greenwald noted last week if Thibeault will pay what’s owed and develop the site, that would be ideal. If the city takes it, the idea would still be to market it for private development, he said.

As City Manager Elizabeth Dragon has noted, taking the property at this point is not in the city’s best interest. Without knowing the extent of the pollution on the site, the cost to clean it up, and how much of that the city would be on the hook for, it’s simply not worth the risk. She and Greenwald described a meeting with Thibeault Tuesday as productive, though it doesn’t seem much movement came of it.

The obvious goal of starting a taking-for-taxes proceeding is to spur the owner to either pay more of what he owes, or perhaps to pressure him into signing off on phase two of the environmental study. If that’s what it takes to gain his cooperation, fine.

But at this point, it seems the last thing the city would want is actually to own, and be responsible for, the contaminated property without knowing its liabilities.