After 18 people were treated and a school-wide evacuation, administration on Muskegon Catholic Central has determined that a student unintentionally sprayed pepper spray in the hallway.

On Tuesday, May 23, the school was evacuated and students were dismissed. Some of the students reported feeling ill and having trouble breathing.

►Related: 18 people treated, released after Muskegon Catholic Central evacuation

The Hazardous Materials Unit tested the air in the school and found no contaminants in the building, concluding it was safe.

Administrators at MCC say based on what was seen and private conversations with the high school principle and guidance counselors, they determined a student with a pepper spray canister on their key lanyard was walking down the hall, opening and closing the lid on the canister.

According to a news release from the school, the student inadvertently pushed the spray nozzle down and released some of the spray.

MCC says they are working with local authorities and the student's parents to come up with the appropriate consequences, however, school administrators do not think the student sprayed the pepper spray intentionally.

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April Stevens is a multi-platform producer at WZZM 13. Have a news tip? Email, visit our Facebook page or Twitter.