The Canberra Olympic Pool in Civic was evacuated and closed after a chlorine leak on Saturday morning.
ACT Fire and Rescue contained and cleaned the leak, which had earlier forced 25 people out of the pool.
An exclusion zone was set up and then later downgraded after firefighters contained the leak.
Atmospheric monitoring found the area was safe and firefighters handed the site back to pool management before 3pm.
The Emergency Services Agency said in an earlier statement firefighters were working with contractors to safely dispose the liquid on Saturday afternoon.
The agency had asked people to avoid the area.