An Indiana high school was evacuated Tuesday because of an unidentified chemical spill that injured at least 21 students and faculty members.

The Indianapolis Fire Department, which responded to the incident, told WXIN that nine students and 12 school employees complained of irritated throats after an unidentified “white, hazy-like cloud” was reported in a girls bathroom.

The Indianapolis Star put the number of affected adults at 13, but agreed that no one had reported serious harm.

“No one was transported to a hosptial and all were treated on scene,” WXIN reported.

“Once they got into fresh air, grabbed some water, everything was good,” Indianapolis Battalion Chief Rita Reith told the star.

HAZMAT teams searched the bathroom in question as well as other areas of the school, but found no residue of whatever caused the smoke cloud.

“At this time, we really have no idea what was deployed inside the bathroom,” Reith told WXIN.

“This is a really scary situation for our students and for our families and this is a school day that has been fundamentally disrupted,” Beech Grove City Schools Superintendent Laura Hammack said.

“So we want to get to the bottom of what’s happened and ensure something like this never happens again.”

Hammack said school administrators were reviewing camera footage from throughout the building looking for answers as to what caused the event.

“A disruption of the school day like what was experienced today is unacceptable and we will work tirelessly to ensure that the cause of the incident is uncovered and appropriate consequences are rendered,” she said.

After the evacuation, students were sent home for the remainder of the day and school activities were canceled for Tuesday night due to what the school system called a “smoke related issue.”

The school will be sanitized prior to reopening Wednesday, the Star reported.

“I am extremely proud of the incredible response by our law enforcement, fire department, and first responders during this very active event,” Hammack said. “Additionally, the BGHS students, teachers, and staff as well as our colleagues at Hornet Park and the Beech Grove Community Center were nothing but extraordinary.

“Thankfully, a potentially frightening event ended with a positive and safe outcome.”

This article appeared originally on The Western Journal.