There is no ongoing risk to the community after radioactive isotopes were located at a Sydney property, authorities say.
A 23-year-old airport worker is being questioned over the incident, the Australian Border Force revealed on Friday.
The find prompted a major emergency services response on Thursday, led by the agency, with a street in the inner western suburb of Arncliffe completely closed off.
ABF Deputy Commissioner Tim Fitzgerald said a warrant was executed at the residence after a range of illicit substances were detected being brought into the country through air cargo in Sydney.
During the operation, low-level radioactive isotopes were detected, prompting a 10-metre exclusion zone being established while fire and rescue personnel in hazmat suits inspected the site.
All up, 52 vials of suspected hazardous materials were located and taken for testing.
"Our officers have done an incredible job under extremely testing circumstances to ensure all of the vials we have located have now been safely transferred for testing and evaluation," Mr Fitzgerald said.
"We could not have done this without the close support of our colleagues, both within the NSW emergency services and across other commonwealth agencies."
Teams from the Environment Protection Authority and Australian Nuclear Science and Technology Organisation were called to the property to assist.
Residents and border force staff were tested for radiation but all returned regular readings, while three people from the address were taken to hospital for observation.
EPA testing confirmed there was no evidence of radiation exposure and ABF says there is no evidence suggesting any national security risk.
"At the forefront of our minds at all times during this operation was the safety and wellbeing of community members and all officers involved," Mr Fitzgerald said.
Radioactive isotopes are commonly used in medicine and other industries.
