type of oil no two oils are alike photo-oxidation more weathered not all oils are the same more weathered photo-oxidation oil type more weathered complex mixture of thousands of chemical compounds more weathered cause more weathered more weathered more weathered crude oil is not a single substance oil chemistry oil type photo-oxidation type of oil photo-oxidation oil spills oil type more weathered No. 2 fuel oil spills No. 2 fuel oil spills oil type oil chemistry complex mixture of thousands of chemical compounds types of oil not all oils are the same no two oils are alike lighter oil products different types of oil and their behaviors when spilled similar physical properties oil chemistry different types of oil and their behaviors when spilled cause not all oils are the same very different types of oils