Police in Arta, northwestern Greece, were looking on Thursday for the perpetrators behind an unprecedented attack on a local high school with an industrial cleaning agent that caused three teachers to be hospitalized with respiratory problems.
According to local media, unknown assailants poured a chemical, believed to be a strong, creolin-based cleaner, into parts of the school.
Emergency services were called when students and teachers began complaining of breathing problems, prompting the evacuation of the premises. Regional authorities have ordered the school closed as special crews remove the chemical.
How or when the agent was administered remained unclear.