ADAIR, Iowa (AP) — Authorities in western Iowa are investigating how a wind turbine blade that’s the size of a football field snapped off. A technician for the Eclipse Wind Farm in Adair discovered the blade in a field Friday morning. Siemens Energy, the turbine manufacturer, is investigating the accident.

Iowa Wind Energy Association President Kathleen Law says it’s rare for a blade to get loose, and she’s never heard of this happening in Iowa. Television station KCCI reports Siemens Energy is working to replace the blade. Most of the blade that fell has been removed from the field.