In searching for the smallest number of categories necessary to contain and organize the challenges expected between now and 2025, five key sectors emerged. Most of the challenges arise from four sectors:
- National Security
- Industrial and Consumer
A fifth sector, Legacy, recognizes that wastes and problems from the other sectors will eventually become a common problem.
Organizing emerging challenges in this simple, yet comprehensive framework, allowed EPA to clearly see and reassess its historical focus on the Legacy Sector.