Lockport Union-Sun & Journal — A chemical reaction that created a cloud of chlorine cloud gas in the basement of Gaskill Preparatory School forced the evacuation of students and staff Monday morning.

Falls fighters said they were called to the school around 9:27 a.m. and when they arrived on the scene they discovered that a school district maintenance worker had “accidentally poured a 1-gallon container of muriatic acid into approximately 20 gallons of liquid chlorine” located in a 50-gallon drum that feeds the chemicals into the school’s swimming pool.

The combination of the acid and the chlorine created a “cloud of chlorine gas” that filled the school’s basement. At that point, firefighters ordered the school evacuated.

Judie Glaser, a district spokesperson, said students were promptly moved to the school’s two evacuation locations, the Hyde Park and 24th Street schools, and parents were notified via the district’s emergency all-call.

“We wanted to make sure the parents were notified,” Glaser said. “Those who are bused would be able to catch a bus, while ‘walkers’ ... would be dismissed to parents. The school contacted each parent to set up dismissal to ensure all children are accounted for before allowing them to leave.”

While the children were being sent home, city fire crews called for assistance from the hazmat team at the Niagara Falls Air Reserve Station Fire Department. Testing showed that dangerous levels of chlorine were still present in the basement.

When the hazmat team arrived, they were joined by Falls firefighters in entering the basement and setting up ventilation equipment. Smoke ejectors were used to vent the fumes and meters were used to monitor air quality levels.

Firefighters tried to drain the mixture in the 50 gallon drum into the swimming pool to dilute it. Because that pumping process was slow, fire commanders on the scene instead decided to drain the chlorine mixture into 5-gallon plastic containers and then pour it directly into the pool.

Once the mixture was in the pool, chlorine levels in the air in the basement quickly dropped and the area was declared safe early Monday afternoon.

Two maintenance workers, who were involved in the incident, were taken to Niagara Falls Memorial Medical Center to be evaluated.

Students were expected back at the school today.