Oil extraction isn't a pretty business, but it's nothing in comparison with the rest of the plastics production process. Once the oil is pumped out of the ground, it has to get to wherever it's going, either a refinery or manufacturing plant. It's often transported by a network of pipelines, some buried, some on the surface. Pipeline clearances are mowed or otherwise maintained in a vegetation-minimal state. Occasionally, a pipeline breaks or leaks.
Oil can be devastating to wildlife and can leave an ecosystem impacted for years.
Evidence indicates that the area affected by the Exxon Valdez spill, more than ten years ago, has still not recovered. After the base product is extracted and transported, a series of chemical processes convert it into one of a variety of plastics. Very basically, the oil is turned into monomers, which are molecules capable of binding together with each other. Some examples of monomers are vinyl chloride and propylene. The monomers undergo polymerization, which creates strings of linked molecules, now called polymers.