Philippine Coast Guard is looking into the cause of the oil spill detected in the waters near Piscador Island, a known diving spot in Moalboal town, about 88 km southwest of here.
Philippine Coast Guard Station Commander Agapito Bibat said they have yet to determine the cause of the spill but the area is part of the Tañon Strait where vessels pass by.
He said that they would conduct laboratory tests on the oil collected to determine the vessel that was responsible for the spill.
Once proven, he added a fine would be imposed on the owner of the vessel.
Bibat said Coast Guard personnel and several residents cleaned up the oil at the shoreline using shovels and had collected at least 30 sacks.
He, however, assured that the oil spill was in minimal level and may have happened on Friday night.
As of Saturday afternoon, Bibat said the oil had started to dissipate.