Some states lead in innovation. Innovation then diffuses over time to other states. Experience demonstrates that prevention is often more efficient, and effective, than control. However, pollution control technologies can transfer pollution from one medium into another. This is a fragmented approach to regulation.
Many environmental problems are transboundary.
For example, air pollution generated by power plants in one state often migrates to others. Some states are more receptive to innovation than others. Some states strive to exceed federal standards of environmental protection. Others seek only to meet federal standards, and nothing more. Federal government continues to provide major assistance to state environmental protection efforts.