STILLWATER, Minn. (AP) – Work on the new St. Croix bridge connecting Minnesota and Wisconsin has been halted after dead zebra mussels were found on six construction barges headed for the river.  The Minnesota Department of Natural Resources is investigating the incident. DNR spokesman Chris Niskanen says none of the barges entered the St. Croix river.  Contractor Ed Kraemer & Sons of Plain, Wis., agreed to decontaminate all construction barges. Niskanen says the company properly treated the hulls with 190-degree water, but failed to scrape the hulls.  Inspectors noticed the zebra mussels on the barges at the construction staging area this week and contacted the DNR. Kraemer spokesman Bob Beckel tells the St. Paul Pioneer Press ( ) the company will make sure it doesn’t happen again.  Kraemer trucked the barges from the Fox River in Oshkosh and from Milwaukee.

—      Information from: St. Paul Pioneer Press,