SUFFOLK, Va. (WAVY) — More than 70 students at Nansemond River High School in Suffolk experienced respiratory issues Tuesday morning after a fire extinguisher accidentally discharged in a hallway, Suffolk officials confirmed.

There was no fire.

Suffolk Fire and Rescue responded to the school, located in the 3300 block of Nansemond Parkway, around 10 a.m. They quickly determined a fire extinguisher, which contains dry chemical powder used to suppress fire, had been discharged. As a result, many students started complaining of respiratory irritation.

Suffolk Fire Chief Michael Barakey told WAVY most of the students were displaying coughing and wheezing symptoms.

Paramedics and firefighters examined the students on scene, in the school auditorium, and determined 11 of them, as well as an adult, needed to be taken to the hospital for non life-threatening injuries. An additional student was also taken to the hospital with non life-threatening injuries by a parent.

The fire department declared this a “mass casualty incident” due to the number of students affected. This is declared when local agencies have an overwhelming number of people needing care. In this case, it does not mean there were casualties.

Suffolk Fire and Rescue is receiving assistance from other local fire departments.

“So a mass casualty basically puts hospitals on alert and area fire departments (in this case) Chesapeake, Isle of Wight, Portsmouth,” explained Chief Barakey. “And so with 70 people reporting irritation or some kind of illness, then that becomes a mass casualty in which we initiate a regional style of response which we’ve got here.”

Barakey said the Fire Marshals led the investigation, which involved reviewing video, and determined that the fire extinguisher fell off its wall mount after a student accidentally bumped into it in a hallway during a class change. It discharged when it hit the ground.

The fire department is working with the building maintenance at Nansemond River High to make sure all of the fire extinguishers are secured well.

Parents of students sent to the hospital and evaluated were notified first, WAVY confirmed. All other parents were called about the incident and a letter was emailed out.

WAVY News got a copy of the letter School Principal Dr. Shawn Green sent to parents about the incident. In it, he said, in part:

“Our school immediately moved to a Code Yellow emergency status to clear the hallways. The incident was contained swiftly, and there is no ongoing threat to the safety of our students or staff.

I would like to express my gratitude to our dedicated staff and the emergency personnel who responded promptly and efficiently to this situation.”

The city of Suffolk and Suffolk Fire & Rescue are working with Suffolk Public Schools to provide additional information as it becomes available.