Niagara Health confirmed that 23 people were transported to the hospital in St. Catharines following a serious workplace incident on Tuesday. According to authorities, the incident occurred around 10:30 AM at the THK Rhythm Automotive plant on Louth Street and Ridley Road area. Dave Uber, Fire Chief of St. Catharines, told CTV News Toronto that a contractor was working and accidentally injured the valve, leading to the release of five liters of hydrochloric acid. Uber stated that the acid turned into vapor, and there were three people nearby as they managed to close the valve, but they were exposed to the fumes.

Officials at the scene said about 20 other people were affected, decontamination showers were used, and most of them were transported to the hospital by bus. Uber continued by saying that the acid exposure was minor, and the other twenty people were taken to the hospital as a precaution: "This chemical usually causes burns to the respiratory system and skin if exposed severely, we do not believe they have this heavy saturation." Bres Bronarski confirmed that paramedics transported nine people to the hospital with minor exposure, while 10 others who were asymptomatic with limited exposure were taken to the hospital by bus.

At 1:30 PM on Tuesday, Niagara Health confirmed that the emergency department at the St. Catharines site had returned to normal operations, with the health agency confirming that all patients were assessed and expected to be discharged at some point today.