SHELDON, Iowa (KELO) — Firefighters in Sheldon, Iowa are trying to figure out what sparked a fire south of town.

Crews were called to a shop that was on fire at 3587 Monroe Avenue Tuesday morning. Authorities say it was a dangerous situation with live ammunition exploding, propane tanks venting and the roof falling in.

The fire destroyed the building along with a two vehicles, a boat and several shop tools.

Officials say firefighters were on scene for about two and a half hours.