Reacting to the civic-minded citizen's infomration, the State Environmental Service (SES) checked out the football-sized metal object and discovered it was emitting ionizing radiation.
The SES's Radiation Safety Centre said the man making the report only reported the item after investigating it on the internet and wisely decided that the experts should be brought in.
Industrial levels of radioactive source cesium were detected within the 55-kilo item. The shielding is reported to be intact.
SES continues its investigation into how the item came to be dumped in a forest.