04/08/2014 at 05:00 PM EDT
A school in Colorado was evacuated Monday after students were exposed to habanero chili peppers near the playground, causing them eye and skin irritations that sent a handful of children to the hospital.
Thirty children and a teacher's aide at Jefferson County Open School were treated for allergic reactions after the students reported symptoms when coming in from recess. A handful went to the hospital, and the remainder of the school was evacuated to a nearby church, CNN reports
A hazmat crew set up a decontamination area outside of the K-12 school, where students were sprayed down over their clothes.
Investigators discovered Tuesday that the culprits were six habanero peppers spread through wood chips near the playground, school district officials told CNN.
"Coming in contact with the pepper oil would cause many of the symptoms that students experienced. It isn't known at this time how or when the peppers got on the playground," county officials said in a statement, KUSA reports
The children taken to the hospital were released the same day, and all are fine, the local fire department reports.
All playground equipment will be cleaned and the wood chips were replaced by Wednesday, when the school reopened.