TAIPEI (Taiwan News) — A vocational student in Taipei’s Xinyi District sprayed his fellow students with a fire extinguisher on Thursday (Sept. 14), causing 18 students to be sent to nearby hospitals.

The incident occurred after an online argument between a second-year student and a first-year student. During a break between classes at around 11:10 a.m., the older student grabbed a fire extinguisher and entered the younger student’s classroom, where he sprayed the dry chemical powder over a large group of students, reported UDN.

School officials immediately called for medical assistance, fearing that students may have ingested harmful chemicals. There were reportedly 18 students who were affected by the angry student’s actions, with several of them inhaling the dry powder.

Fire extinguishers that are approved for use in homes and public places typically do not contain chemicals that are toxic to humans. However, the mono-ammonium phosphate used in most dry powder fire extinguishers will cause irritation to the respiratory tract if inhaled, and it may also cause irritation to some skin types.

None of the students affected by the incident were seriously injured, but three reportedly suffered red and swollen eyes, per LTN. The student who sprayed the fire extinguisher will be investigated and may face punishment by local authorities in accordance with the Juvenile Justice Act.

Police have contacted the students and their families to inform them of their legal rights. Some families may choose to press charges against the offender.

Additionally, school officials have sought to dispel rumors that a physical fight occurred among students. They emphasized it was an online disagreement that led to the second-year student’s actions.

The school will reportedly organize counseling sessions for students who were directly involved in the incident.