Plans to tear down the old Royster Clark building on Madison's East Side appear in doubt after a state official last week signaled that it could lead to contamination of groundwater below the site.

Agrium Inc., the owner of the property at 902 Dempsey Road, has asked for permission to demolish the main building on the property. The plan commission will decide on the permit Nov. 3, according to Ald. Larry Palm, whose 15th District includes the site.

But in a Friday letter from Department of Agriculture, Trade and Consumer Protection hydrogeologist Richard Graham to the city, Graham points out that the building's roof is considered a "cap" over an area that might contain nitrogen-contaminated soil.

Taking down the building could let rain or melting snow seep through cracks in the building's floor and drive some of that potential contamination into groundwater.

Palm, who had been in favor of tearing down the building, said the DATCP's opinion "certainly changes some opinions that I have" and that he would not support demolition if it led to further environmental problems at the site.

Graham wrote that the state agency could support demolition if Agrium removed the building's floor and any contaminated soil underneath.

The 26.7-acre Royster Clark property — which was home to a fertilizer manufacturing plant for more than 50 years — has long been eyed for redevelopment if it could be cleaned up. State officials have been coordinating such an effort since 2002.

In March, city officials said two real estate development firms had decided not buy and redevelop the property because of the weakening market and the prospect of having to undertake costly demolition work at the site.