According to the Environmental Protection Agency (EPA), between 500 billion to a trillion plastic bags are used worldwide each year. The bags find their way into landfills, oceans, rivers, and parks. You can see plastic bags caught in the tops of trees and blowing around parking lots. Normal plastic bags do not decompose quickly. Whether they end up in a landfill, a park, or the ocean, the bags will be around for centuries. When they finally begin to break down minute toxic substances will seep into the ground and be washed into lakes, rivers, and the oceans.