Investigations are still being carried out to determine what caused residents in an apartment building to be taken ill. 

Air testing ruled out carbon monoxide poisoning and the notice telling to residents 'not to drink' tap water has now been lifted. 

Sixty residents were evacuated from Bay Chambers in West Bute Street, Butetown, Cardiff on August 29, after 16 people reported nausea and headaches. 

Residents have been allowed to return to their homes but were initially told ‘not to drink’ from taps and bottled water was provided. 

The residents were initially evacuated from the building by fire crews and a rest centre was established at the Coal Exchange. 

Five people were taken to the hospital by the Welsh Air Ambulance Service University Hospital of Wales for testing and one person was kept in overnight for observation.  

Four fire engines attended the scene of the incident with specialist officers and equipment to establish the origin of the suspected hazardous gas escape. 

The fire service arrived at the incident at Bay Chambers, West Bute Street, Butetown, Cardiff at 22.18pm.  

A spokesperson for South Wales Fire and Rescue Service said: “Fire crews at scene were unable to detect any hazardous materials after extensive atmospheric monitoring.” 

Public Health Wales contacted Dŵr Cymru Welsh Water and agreed that ‘Do Not Drink’ advice would be issued to the affected block of flats as a precaution whilst investigations continue. 

Cardiff Council’s Incident Support Team and Family Housing Support staff were on site during the incident to support the emergency services.  

Alternative accommodation was arranged, and transport placed on standby for use if residents needed to be moved further afield, though none of this was required. 

Multi-agency briefings were held at the scene and a Tactical Coordination Group was established to allow partners to discuss tactical priorities to manage the incident.   

This included the South Wales Fire Service, South Wales Police, Cardiff Council, Public Health Wales, Welsh Ambulance Service Trust, Welsh Water, and other agencies. 

Public Health Wales continues to work with multi-agency partners to determine the cause of the incident.