The Minnesota Vikings may end up on the hook for spending half a billion dollars on the proposed new stadium at Arden Hills.

"If you look at the cost escalation for a project like this...and the fact their contract, as written now, they are responsible for that, I think it is fair to say they'll be maybe close to half a billion dollars," Gov. Mark Dayton said Wednesday.

Lester Bagley, Vikings vice president of public affairs and stadium development, did not warm to the half a billion figure but did not rule it out.

"The last public number was 407 (million dollars)," he said. Adding on to that , he said, is "the commitment to make it a people's stadium" so that events besides football games can happen at the new stadium, a move that adds another $20 million a year. Plus, "we're on the hook for any cost overruns on the stadium" and, Bagley said, the Vikings have or will agree to pay any cost overruns on the surrounding roads that would need improvement for the new stadium.

He said the ultimate amount the Vikings would pay was "in negotiations."

Both Bagley and Dayton said the Vikings are still only looking at the Ramsey County site in Arden Hills for their new home.

"It is plan A and it's Arden Hills," Bagley said.

Dayton said if everything moves forward smoothly the state could still have a special session this year to approve the state's financial contribution and allow for Ramsey County's contributions.

But there is a lot of ground to cover between now and then.

By mid-October, the state is due to produce a quick, but complete assessment of the Arden Hills site that would look at both environmental and transportation issues.

Bagley said he was sure that would be an "honest, fair assessment of the project" that would help eliminate the risk involved in a project of that size.

"We think and we hope that it will give us the green light," Bagley said.