On Thursday, November 10, 2022, around 8:15 am, the Bridgeport ECC received a report of an activated fire alarm at Bassick High School on Fairfield Ave. Engine 4, Ladder 11, and Battalion 1 responded. Enroute to the incident, responding companies were updated that a call had been received from the school reporting an unknown substance was sprayed in a bathroom on the 3rd floor. Companies investigated the release of a possible chemical irritant in the building, Ladder 5 was special-called to the scene for ventilation. Engine 3, Rescue 5, Safety Officer 1, and 6 ambulances were requested to the scene due to approximately 30 students and staff reporting the effects of exposure to the substance. It was soon decided to request the Fairfield County Hazardous Incident Response Team to the scene because nobody could confirm if the irritant was pepper spray or another chemical. DEEP was also notified of the incident. A full team activation was issued for the Fairfield County Hazmat team. Several assets from the region responded to the scene, along with Hazmat 1 from Westport. Technicians metered the building and worked to identify the possible irritant in the building. After extensive investigation, it was concluded that the irritable substance was a pepper spray/mace-like substance. The school was dismissed around 11:25. Around 12 noon, the scene was turned back over to the school, and remaining companies returned to service. There were no transports to the hospital. The Bridgeport Police Department and Bridgeport Board of Education are investigating this incident.