A romantic gesture from one prisoner to another led to the evacuation of the Port Lincoln Prison administration building on Monday morning.
At 10.15am on Monday, July 9, a Department for Correctional Services spokesman said about 20 staff were evacuated from the building after powder was found in an envelope during prisoner mail processing.
SAPOL and the MFS were called to the scene and soon contained the room.
The envelope, containing letter and powder, was taken away for testing.
It is understood that the envelope contained a love letter from a female prisoner who was writing to an inmate at the Port Lincoln prison.
To personalise the letter she decided to scent the envelope with lavender talcum powder.
There were no injuries, and staff soon returned to the building.
The spokesman said the woman would likely have a conversation with a prison staff member about being more careful with her letters.