Police say a teenager brought a homemade explosive device to a western Michigan high school and accidentally detonated it in class.

He and five other people were injured, including a teacher at Newaygo High School.

The Newaygo superintendent says the 16-year-old showed a "serious lack of judgment."

Peg Mathis says the student wasn't trying to hurt others.

The high school was evacuated and students were sent home because of odor and smoke.

The student with the device had "moderate to severe injuries" while four more students and the teacher had minor injuries.