YOUNGSTOWN, Ohio (WKBN) — There was a large emergency response to the downtown YMCA just before noon on Wednesday. It was getting a delivery of chemicals for the swimming pool but there was a problem.

“One of the chemicals got mixed into the chlorine tank inadvertently that did have a reaction with it that did put off some chlorine gas,” said Youngstown Batallion Chief Chad Manchester.

Manchester said it was aluminum sulfate, and the reaction caused a puff of gas.

The Y’s CEO took two people to the hospital with minor breathing problems, and a third was taken by ambulance. They have since been released.

“So when the two chemicals got mixed together, it was pretty serious because it caused an inhalation hazard that did spread a little bit through the building,” Manchester said.

The Y was evacuated.

A fourth person was checked on The Y’s steps but needed no further attention.

That left the situation to the fire department and Hazmat teams, which responded. They still had to clean up the spilled chemicals and make sure there was no more chance of a reaction.

“The Hazmat team is very good at what they do. They’ve done considerable research on the chemicals that were mixed together. They’re going in in suits that will protect them and were able to neutralize the materials,” Manchester said.

The Y closed for the day.

Joe Gorman contributed to this report.