READING, Pa. — It's a chemical mix that could kill.

"It can suffocate you and kill you. It's a pretty dangerous chemical that was created," said Lt. Trent Zulick, Reading Fire Department.

Firefighters and EMS worked quickly to save 20 people, including six kids, some as young as 5, after authorities said a chlorine mix got messed up underneath the pool of the YMCA at Reed and Washington streets in center city.

"Kind of double or triple or quadrupled the problem, and that violent reaction creates chlorine gas," said Dep. Chief Tom Kemery, Reading Fire Department.

Symptoms hit swimmers.

"Irritated eyes, irritated throats," said Zulick. "Kids had shortness of breath."

The sick got sent to Reading Hospital and St. Joseph Medical Center, while first responders worked to get the gas out of the building.

"We set fans up, brought fresh air in," Kemery. "We had to do a search to make sure nobody passed out."

Five ambulances were involved in the response. Dozens of other people had to be evacuated from the building. The chemical mix was emptied into the pool to dilute it.

"The volume of the pool compared to the volume of liquid dilutes quickly," said Zulick.

The firefighters said they don't think people will suffer any long-term effects due to the level of exposure. They said it's an incident that could potentially happen anywhere but that this situation was handled quickly.

"It certainly could have been much worse."

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