Radioactivity can come form many sources, some that you may not consider immediately. Sealed radioactive sources are usually housed in an outer casing or container which acts as a shield to the radiation.
Examples of sources include:
redundant industrial equipment, called ‘orphaned sources’.
‘Orphan' sealed sources from redundant industrial plant can present an immediate hazard in the scrap yard if this shielding is missing or damaged on initial receipt. They may present little risk if the container is properly closed and locked.
They are out of regulatory control (typically containing caesium-138, cobalt-60 or americium-241 sources), found in:
old gauges and dials,
Naturally Occurring Radioactive Material (NORM)
NORM typically contains uranium-238 and thorium-232 or Low Specific Activity (LSA) scale (containing radium-226) found in:
rocks (especially granite)
soils (especially clays),
specialist alloys such as used in aerospace industry and some welding rods;
nuclear material waste contamination of imported stainless steel and copper; and
imported steel through contamination during production.