Part of Port Erin beach was closed yesterday after diesel was found in the water.
The substance was found on the lower part of the beach and on the surface of the sea.
The Coastguard carried out an initial clean up along the High-Water Line.
However due to the 'widespread covering' the Commissioners ordered the lower part of the beach to be closed for public safety.
It’s believed the diesel will evaporate quickly – conditions will be monitored over the following tides and the closure will be lifted as soon as possible.