The Minnesota Vikings are struggling to gain support at the state Capitol for public funding of a new football stadium, but their building plans for Arden Hills soon could have a possible advantage over competing sites in Minneapolis.

In a word: land.

Ramsey County commissioners voted 7-0 Tuesday to approve the county’s end of a deal to buy from the federal government about 500 acres of polluted federal land in Arden Hills for construction of the stadium.

The deal is contingent on $28.5 million in state funding for the site of the former Twin Cities Army Ammunition Plant. The county will offer $300,000 in refundable “earnest money” as a down payment, but county officials can rescind the offer if the state chooses not to finance the deal.

The actual purchase would go through by Aug. 1, 2012, pending federal approval.

“We have until August to walk away. There’s plenty of out clauses,” said Ramsey County Commissioner Tony Bennett, a key architect of the Arden Hills stadium proposal.

The deal requires the federal government to deduct cleanup costs from the sale price, bringing the location to standard for at least commercial or industrial development.

Proponents envision 430 acres set aside for the stadium, parking and related businesses, and 128 acres used for parkland to the northeast adjoining the existing Rice Creek wildlife corridor.

The parkland would include a nature trail from County Road I to County Road 96. The title to the parkland would be transferred to the county from the Army and through the U.S. National Park Service.

Commissioners Janice Rettman and Victoria Reinhardt opposed an earlier proposal to fund construction through a countywide sales tax. But with that proposal sidelined by the governor and state lawmakers, Reinhardt said, she is comfortable voting for the land deal, which would help remediate the state’s largest federal Superfund site.

“A lot of people aren’t even aware of the fact that we have a wildlife corridor that is over 400 acres,” said Reinhardt, chairwoman of the county board. “Enhancing that is my priority here.

“This action today is contingent upon state financing. It is not contingent on a Vikings stadium being built there.”

Commissioner Toni Carter agreed, noting the federal government has agreed to “credit” or reimburse the county for cleaning up even any hazardous waste and contaminants yet to be identified on the site.

“Although this is being driven forward by the catalyst of a stadium, this appears to be a pretty good deal for Ramsey County,” Carter said. “We perhaps will not see a moment in time like this again.”

The agreement calls for the county manager to begin accepting bids for demolition of roughly 200 structures and related utilities on the property and the cleanup of any soil contaminants.

In 1941, the Army bought nearly 2,400 acres in what was known as Mounds View Township and converted it into an ammunition plant. The facility, which continued to manufacture munitions through the first Persian Gulf War, was included inside the boundaries of Arden Hills when the city was incorporated in 1951.

The mayor of White Bear Lake and Arden Hills city officials, among others, attended Tuesday’s meeting. Commissioner Rafael Ortega said Arden Hills, together with the county, has struggled for years to figure out what to do with the property. The deal with the federal government would allow the cleanup of the largest piece of contiguous land on the site and ready it for redevelopment.

Officials had investigated the possible use of the site for everything from housing to some form of NASCAR facility.

“The Vikings are a project that’s here and now. If we can make that happen, we solve the problem,” Ortega said. “Otherwise, we have 500 acres of brownfields” for decades to come.

Commissioners Jan Parker and Jim McDonough also spoke strongly in favor of moving the Vikings onto the land.

“The county’s role is really in facilitating this. We’re not putting our own money in,” Parker said. “First priority is the Vikings stadium. Hopefully, this will be the stimulus that will put it over the edge. … But secondly, Plan B, if the Vikings stadium does not get legislative approval, we still want the state to fund the cleanup. At a minimum, we have raised the awareness (of the site).”

McDonough noted a recent report from the Metropolitan Council estimated cleanup and acquisition costs at as much as $70 million, more than twice the price of the land deal.

“We have site control,” McDonough said. “We’ve minimized the risk.”

Bennett thanked the seven-member county board following the vote.

State funding for the $1.1 billion stadium project remains uncertain, with Gov. Mark Dayton and key state lawmakers concerned about how to raise the more than $650 million the Vikings seek.

Frederick Melo can be reached at 651-228-2172.