Traces of radioactive contamination have been found on the shoes of workers demolishing a former nuclear power station.
It was detected on around a dozen people on Thursday as they prepared to leave a building which they were preparing for demolition.
Dounreay Site Restoration Limited (DSRL), which is overseeing the decommissioning of the site in Caithness, has launched an investigation.
It said that the building is in a "controlled" area, where contamination is possible, and controls are in place to manage it.
In a statement DSRL said: "The area was isolated and follow-up surveys confirmed that the contamination was confined to a small area. An investigation is under way.
