COLUMBUS, Wis. (AP) – The cause of a small explosion and fire at American Packaging Corp. in Columbus is under investigation.   Fire officials say a sprinkler system helped contain the fire to the room where it started Monday. Workers were evacuated from the building. And, one person thought to be missing was later located outside.  The Beaver Dam Daily Citizen (http://preview.tinyurl.com/b3omcx5 ) says the company recently underwent a $17.5 million expansion. An explosion at the factory in 2009 killed 47-year-old Jerrod Doxtater.

—      Information from: Daily Citizen, http://www.wiscnews.com/bdc