The land is befouled with hazardous waste from the decades it held a munitions plant. How much, and how expensive, remain the key questions.
Various ammunition factories are visible from the top of the old steam plant at the Twin Cities Army Ammunition Plant in Arden Hills. The U.S. Army spent $200 million to clean the site for industrial use, but a public facility may need more scrubbing. .
If a 430-acre site in Arden Hills becomes the new home of the Minnesota Vikings, its stands of long grass and blossoming trees will be transformed into a vast expanse of parking lots and plazas -- perfect for the pre- and post-game partying fans adore.
That vision helps explain why Vikings owner Zygi Wilf chose Arden Hills over the less expensive Metrodome site.
But what many fans might not realize as they don their purple jerseys and break out the brats is that they'd be tailgating on what was one of the most-polluted pieces of ground in Minnesota.
The site is contaminated with mercury, lead, solvents, PCBs and other hazardous substances from its days as a U.S. Army munitions plant. And though the Army has spent some $200 million to clean up the worst of the contamination, officials at the Minnesota Pollution Control Agency say a stadium development would probably need further cleanup before the land would be safe for the public.
Rolled into the $1 billion public-private bid for the facility is an estimated $18 million to finish cleaning up the hazardous materials. But officials acknowledge that is a bit of a guesstimate until developers undertake a new round of soil tests. "There have been a lot of holes drilled, but we don't know everything at this moment," said Greg Mack, Ramsey County's director of Parks and Recreation and the county's expert on the site.
Nevertheless, key players remain confident.
"That's a risk on the project," said Ted Mondale, Minnesota sports facilities commissioner. "But I have researched this and have every reason to believe that the [$18 million] number is right."
Ramsey County Commissioner Tony Bennett said in an e-mail: "If the Vikings end up in Arden Hills, we will have cleaned up a Superfund site and an eyesore."
They have some reason for confidence: Minnesota already has cleaned up and developed hundreds of regulated pollution sites -- including the land where Target Field and TCF Bank Stadium stand today.
The Arden Hills site, which continues to be the focus of offstage negotiations at the Capitol, is one of the last large empty tracts in the Twin Cities. It has remained undeveloped for a reason: It's part of a Superfund site; it was polluted enough to win a spot on the federal government's priority list of legally supervised cleanups. It's been on the list for decades, a designation that has derailed a dozen development plans, most recently in 2009.
The source of pollution was an ammunition manufacturing facility that once employed 26,000 workers who made armaments for soldiers from World War II through the Vietnam war. Over 40 years, the land became contaminated with various chemicals in various spots.
The Army has cleaned up the worst of it, following an agreement in the 1980s with the U.S. Environmental Protection Agency and state pollution officials.
The biggest problem was polluted water. The Army installed a groundwater treatment system on the site and local municipalities have installed treatment systems to protect drinking water for nearby residents.
Much of the ground was polluted because the munitions facility dumped manufacturing residue on the site, said Mike Fix, the U.S. Army representative who manages the land. Most of the contaminated soil has been hauled away to hazardous-material landfills, he said.
Today "we don't think there is a lot there," he said.
Nonetheless, it's not ready for the tens of thousands of fans and tailgaters who could be exposed to contaminants at each game.
The Army was required to get the property up to a level that would be safe for industrial use. That, said officials with the Pollution Control Agency (PCA), is a pretty low standard.
"We allowed a higher level of contamination to remain on the property," said Amy Hadiaris, a hydrogeologist with the PCA. "If the property is bought by someone else for development with more access by the public, we would require additional cleanup."
How much -- and how much that would cost -- is the question everyone is asking.
The answer depends on how the land is used and the outcome of additional soil testing in the works. For example, the most problematic area is the southeast corner of the parcel, where the Vikings' plan calls for a parking lot. State pollution officials said if more contamination is found, they could require the developer to remove soil to a depth of two feet before it lays asphalt.
Ryan Cos. did testing
Ramsey County's Mack said if the Legislature and the state sign off on the project, then the county and team will work out a plan with the PCA on how to proceed.
Much of that testing, however, has already been done. Ryan Cos., the Minneapolis developer, spent millions of dollars on an environmental assessment as part of an ambitious residential and commercial proposal for the site that it dropped in 2009.
The environmental standards for the project were much higher because of the residential component. Those costs, combined with the crashing real estate market, made the project prohibitively expensive, said Rick Collins, Ryan Cos. vice president of development.
"That's proprietary," he said.
Mondale said Ryan Cos. has not shared its report with government or team officials -- though it would like to, for a price. "They've offered to sell it to the Vikings for quite a number," he said.
Fix, of the U.S. Army, also wouldn't say how much additional cleanup would cost. But the overall purchase price for Ryan, for a slightly larger version of the parcel, was $43 million, he said. On a per-acre basis, that's essentially the same as the $30 million estimate for land acquisition and cleanup contained in the Vikings deal, Mack said.
The Ryan project fell apart over how much the Army would spend to finish cleaning up about two dozen hot spots that have contaminants above the level allowed for industrial development and building demolition, Fix said.
"That's where we couldn't come to terms with Ryan," he said.
And that's where Ramsey County and the team will still have to come to terms with the Army, he said.
Josephine Marcotty • 612-673-7394