Before he left office in early May, former First Selectman Ken Flatto maintains, the Fairfield Metro train station was on track, on schedule to open in a few months and -- most importantly for town taxpayers -- under budget.

A month and a few weeks later, his interim successor dropped a financial bomb Monday when he told Representative Town Meeting that Fairfield was on the hook for cost overruns that could reach $6 million.

The main problems: More contaminated soil on the former industrial site than anticipated and where to put it once it's excavated.

Whatever the backhoes dug up during the month of May, it sure wasn't a treasure chest. To the contrary, it has put the town in a deep hole and raised alarming questions about the oversight -- or rather lack of it -- for one of the biggest projects the town has undertaken.

The station is a partnership of the state, the town and a private developer.

And Flatto last spring agreed to a contract modification with the state that made the town responsible for any cost overruns. That modification was approved in an open meeting of the Board of Selectmen -- which at the time meant Flatto and fellow Democrat Sherri Steeneck.

As with any municipal mess of this magnitude, Monday's week's revelation prompted immediate finger pointing and some immediate misinformation.

Some were ready to hang Flatto from a Post Road lamp post because, they said, he never told RTM or the Finance Board that the town would be liable for cost overruns. Those folks can put their rope away. It was no secret.

Flatto briefed the RTM about the contract modification on May 24, 2010. According to minutes of that meeting, an RTM member specifically asked what would happen if costs went over budget, and Flatto replied that the state would pay no more than the money it already had committed.

Michael Tetreau, the interim first selectmen, was on the Finance Board when Flatto made the deal and said he has known all along the town would have to pay for overruns. The two Republican candidates for first selectman -- RTM member David Becker and Finance Board member Robert Bellitto Jr. -- said they've known all along, too, Bellitto noting it was reported by local media a year ago.

That Flatto did not keep the modification a secret, however, may be where his free pass begins and ends. The lack of project oversight and the appearance that the new environmental issues appeared out of nowhere a month after he departed raise more questions than Flatto so far has provided answers for.

The debacle smacks of nobody watching the store, of being asleep at the switch.

Tetreau quite correctly says that a project with as many unknowns as the station should have been closely managed. The town should have been aware based on escalating soil-testing costs that the next shovelful could unearth more contamination and a huge, hidden cost.

A host of officials say Flatto's consistent message had been that all was well with the project, nothing to worry about. But detailed project-management reports never were issued.

The town now will hire its own on-site construction manager to see the project through to completion, Tetreau said. That Flatto did not have one in place is alarming -- especially after his controversial decision to remove the town Conservation Department from environmental oversight.

The Finance Board is properly arranging an independent audit of project finances but, like many, is looking for information.

Fairfield taxpayers meanwhile have every right to be angry and to demand that those culpable be held accountable. There have been calls for a formal inquiry --some favoring an investigative committee, others a "special prosecutor."

As RTM majority leader James Millington suggests, the key line of questioning should be "What did you know, and when did you know it?"

At this time there is no known evidence of criminal wrongdoing by anyone. And while a civilian inquiry would be worthwhile, without the power to compel testimony under oath, such a probe might not have the teeth to get at the full truth.

Still, a lot more answering must be done.