(CNN) – Radioactive mini capsule Missing in Australia It was found on the side of a road, after a difficult search similar to trying to find a needle in a haystack.

Officials in the state of Western Australia announced the discovery of the capsule on Wednesday afternoon, six days after the capsule was found missing from a package sent from a mining site in the north of the state to Perth, the state capital.

Authorities believe the capsule, which contains highly reactive cesium-137, somehow fell from the back of a truck while it was being transported 1,400 kilometers (870 miles) along the Great Northern Highway.

Western Australian authorities are searching for the small radioactive capsule that is believed to have fallen from a lorry. (Fire and Emergency Services Department/AP)

The capsule’s disappearance prompted an extensive roadside search with specialized radiation detection units, and prompted warnings to the public not to approach the capsule, which could cause severe burns on contact with the skin.