The Western Isles local authority has warned that oil deposits have appeared on the coastline near Stornoway Airport on Lewis.
Comhairle nan Eilean Siar has reported that the oil contamination is affecting “various locations” on the coastline between Swordale Beach and Holm on the east coast of the island.
It says it has been liaising with the the Coastguard and other agencies since the small oil globules were first reported on Monday.
A Comhairle spokesperson said: “HM Coastguard and the Comhairle have been monitoring the area. Following foot patrols only very small quantities have been found at sporadic locations.
“Given the small quantities and the sporadic spread over a large shoreline there is no current planned activity other than continued monitoring. Please report any sightings to the Coastguard Stornoway station on 01851 702013.
“Contact with the oil globules could cause skin problems and swallowing the oil may cause serious health effects.
“It is a sensible precaution for you, your children and your animals to avoid contact with any areas of the beach affected by the oil.”