Students were evacuated from a school in central Iowa this morning after a fire and small explosion. It happened in a construction area outside Summit Middle School in Johnston.

Johnston Fire Captain Tim Memmers says there were some tense moments for firefighters as they were informed on their way to the scene that the fire resulted in an explosion. “We knew, that being 9:06 in the morning and the week after spring break, that we had an occupied middle school,” Memmers said.

No students were hurt, but two construction workers received burns and cuts. Memmers said the two workers were transported to Mercy Medical Center with non-life threatening injuries. The fire and resulting explosion were believed to be caused by the combination of sparks from a cutting torch and fumes from an adhesive.

The evacuated students were allowed back in the building within 40 minutes. Firefighters and emergency personnel from more than a half dozen nearby communities responded to the incident.