Ponds Forge sports centre was cordoned off at the weekend after a chlorine leak.
Firefighters were alerted at 4am on Saturday and sealed off surrounding streets as a precaution.
The emergency came only 10 days after the swimming pools were shut temporarily by a car crashing into the building, near the chlorine control panel.
The sports centre is open as normal now. Crews left the scene at 7.30am on Saturday once chlorine levels were deemed to be ‘at an acceptable level’.