GEISMAR - The more than two dozen people who were treated at local hospitals following gas fumes at Dutchtown High School have been discharged.

Students headed back to class Thursday after the campus was evacuated due to a reported gas leak in the school. 

The school system says the incident was due to lawn mower fumes going into the air vents of the school. Multiple people reported feeling nauseous and ill.

The school said Thursday afternoon the odor was caused by a mower parked in front of a main fresh air intake outside the school. The intake caused the mower's exhaust to permeate throughout the school building.

Parents were allowed to check their students out of class early, and all absences will be excused.