Hazardous materials crews were called to the L.A. Fitness on Scriber Lake Road around 6 a.m.
Buzz Dezilla was one of about 30 people at the gym and said there was an overpowering odor coming from the pool area.
"It smelled kinda like chlorine," he said, "but I'm not sure exactly what it was. My eyes are still a little watery."
The staff had apparently posted advisories at the front desk and in the locker rooms that morning to steer clear of the pool while the problem was figured out. But an employee discovered the crack in the pump, called the fire department and everyone inside was ordered out.
HazMat crews made entry into the mixing room for the club's pool where there was a chemical reaction. The Hazmat team shut down the mixing system, washed down the room and verified the air quality to be at normal levels before they turned the club back to the owners.
They were then decontaminated out in the parking lot.
Fire officials say the leak was confined to the one room inside the building; however the pool area will stay closed until repairs have been made and reevaluated.
No one was hurt during the incident.