Mayoral candidate Tim Holden charged Mayor Chris Coleman on Friday with covering up dangerous levels of contamination around Midway Stadium.
The St. Paul Port Authority plans to convert the site into a business park once the Saints move out.
But Port Authority officials said that they’ve done extensive testing on the 13-acre site and found the pollution to be of the type and amount typically found at industrial sites.
Holden said experts tell him that pollutants from the nearby State Fairgrounds leeched into the Midway site, once the fair’s dump ground, turning what he called “a $3 million asset into a $30 million liability.”
Port Authority project manager Monte Hilleman said a 2011 due diligence study — using several soil borings and test pits — found benzene, mercury and naphthalene, as well as diesel fuel in the groundwater and high levels of methane.
He said cleanup costs likely will range from $2.7 million to $3.2 million.
A spokesman for Coleman had no comment.