Students headed back to Yonkers Middle High School Thursday, a day after thousands of people evacuated the building amid noxious fumes that sickened more than 100 people.

"It seems to me, it's almost like some type of prank," said Mayor Mike Spano (D-Yonkers). 

Before noon on Wednesday students and some staff in and around the cafeteria area suddenly became ill. Symptoms included nausea, coughing and watery eyes. Police are trying to determine whether pepper spray was used at the school.

About 1,700 students and staff were evacuated onto Spruce Street and a triage area was set up for sick students and staff. "It came on the announcements and you heard the urgency in the principal's voice. She was like, 'This is not a drill and everyone needs to evacuate,'" said student Erik Kantor. "You could see everyone was very nervous."

"I was pretty freaked out. Everybody was going crazy," said another student. "Everybody was just running and screaming."

More than 100 people were taken to several hospitals to be examined, but mostly as a precaution. No one suffered serious problems or needed to be admitted; all were released within hours. 

By Wednesday evening, police swept the entire school building. The cafeteria and kitchen were cleaned.

Police, who are reviewing surveillance video, say that if this was a prank, whoever is responsible will be prosecuted.