SUSPCIOUS white powder discovered in an envelope at a Sunshine Coast post office has prompted a quarantine and total lockdown.
Staff were quarantined for more than three hours last night after the white powder was discovered at the Nambour Mailing Centre.
Police and fire crews were called to the Perwillowen Road post office at the Nambour Business Hub just after 6pm to investigate the potentially dangerous substance.
Ambulance officers remained on stand-by.
Anyone exposed to the white substance remained inside the building as experts took a gruelling three and a half hours to investigate the white substance's nature.
Three people were decontaminated in the showers of the Burnside facility at 7pm.
Staff were given the all clear to go home at 9.24pm, as investigators revealed the white powder to be a food starch substance.
Queensland Ambulance confirmed that no patients were treated as a result of the ordeal.
Australia Post representative Michelle Skehan confirmed with the Daily that the post office went into lockdown last night.
"Australia Post takes the safety of all of our staff extremely seriously," she said.
"Relevant authorities isolated the Nambour Mail Centre for a short time yesterday evening following the detection of suspicious mail items.
"HAZMAT and QLD Emergency Services conducted tests on the items and operations have returned to normal and most importantly no-one was harmed."
A spokesperson from the Queensland Police confirmed this morning that police are investigating the matter.
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