At least 22 Kirby High School students were treated by first responders after a bottle of hydrochloric acid was thrown down a hallway, said Lt. Wayne Cook of the Memphis Fire Department.
The high school students complained of eye irritation and headaches shortly before 1 p.m.
Once outside the students started to feel better.
Lt. Cook said the liquid substance in the bottle was positively identified as hydrochloric acid after five hours of analysis by their Hazmat crew.
It was reportedly brought to the school by a high school student.
Some students who were treated said it smelled like a smoke bomb.
Several parents were alerted to what took place and took their children to area hospitals for treatment.
The incident remains under investigation by Memphis City Schools and Memphis police.
Police said the school has surveillance cameras and they will be reviewing footage.