OAKDALE, Minn. (AP) -- To remember the collapse of a busy highway bridge, Minnesota historians have preserved a battered school bus door, an emergency worker's shirt and an Interstate 35W sign.

They're all artifacts from the 2007 disaster that killed 13 people. But five years later, displaying those items is still a sensitive issue. Viewings are by appointment only, and there are no plans for a permanent exhibit at the state history museum.

Historians say a couple of the artifacts are expected to be part of a broader display on Minnesota history this fall.

Meanwhile, the mangled steel girders and connector plates from the fallen bridge remain locked away at the state Transportation Department until the last lawsuits are resolved. Officials aren't sure what they'll ultimately do with the parts.