Three people remain in hospital after an outbreak of Legionnaires' disease in Sydney's CBD.
A fourth person was discharged on Saturday morning after being treated for the infection, NSW Health said.
So far eight people have been identified as having contracted the potentially deadly disease, with the culprit believed to be a contaminated cooling tower.
The search for the source is concentrating on an area between Druitt, Market, Sussex and Elizabeth Streets.
Legionnaires' disease is a type of pneumonia caused by a bacterial infection of the lungs that can develop after someone breathes contaminated water vapour or dust.
Anyone who lives, visits or works in the Town Hall area and develops symptoms of Legionnaires' disease has been urged to visit their doctor.
