Freshly-layed bitumen is thought to be behind a strong gas-like smell which made its way into Strath Village on Wednesday morning.
Emergency services were called out to Strathdale shopping centre about 9.30am after staff at the NAB inside the centre alerted them to the gas-like smell, suspecting a gas leak.
Fire crews cordoned off the entrance to the centre while working to determine the cause of the smell.
Senior station officer John Griffiths said workers were laying asphalt in a nearby car park, and it appeared the smell of bitumen was coming in via the centre's air-conditioning vents.
He said NAB workers chose to self-evacuate due to the gas-like smell.