The 24-year-old walked into the lobby of his alma-mater asking to visit with a teacher he had known in school.
When he was told no, the man grabbed the fire extinguisher and began spraying it in the faces of anyone who was unfortunate enough to be close to him.
The New York Daily News reports 17 people including students, guards, and teachers from the Liberty High School Academy for Newcomers were injured with ten requiring hospitalization.
ABC 7 reported that some of the students were overcome because they have asthma and were unable to breathe.
The man finally taken down but not before he was able to spray his way to the fifth floor causing havoc all the way.
All ten of the victims who were sent to the hospital have been released and none of the injuries were considered serious.
Cops say the guy had been diagnosed with schizophrenia in the past so he was taken to Bellevue Hospital for a psychiatric evaluation.