Class was canceled today in the University of Northern Iowa’s Industrial Technology Center following the discovery of a mysterious white powder on several spots around the floor in a classroom. U-N-I Spokesman Jim O’Connor says just after two this (Monday) afternoon the all-clear came to re-enter the building. Cedar Falls Fire and Rescue gave the all-clear to re-open the building after on-site analysis determined the white powder was ceiling material. While the reason for the debris sifting to several spots on the floor still wasn’t clear, janitors didn’t rule out mice chewing on something. The building’s still closed to the public but faculty and staff were allowed back in, and classes will be held Tuesday morning as usual. Custodians going through the building were on their normal rounds this morning, and spotting some material they felt wasn’t common in a classroom, so they notified school officials who called the U-N-I police and they took it from there. O’Connor says the janitorial staff made the right call. That’s normal protocol, he says, especially since 9/11. When custodial staff spot something odd or suspicious they’ve been trained to report it, and he says they know what’s normal in a building. U-N-I staff just went through training on that topic a couple weeks ago, so he says it’s all fresh on their mind. The alert came this morning just as classes were set to resume following U-N-I’s winter break.