The threat of Chemical Warfare (CW) may have increased even as the nuclear threat may have decreased. Terrorists and threatening countries can easily convert factories or use only a van to manufacture chemical weapons. However, no current operational U.S. military aircrafts are designed with any type of CW defense. Nuclear, Biological, and Chemical (NBC) filters will be used in the future Environmental Control Systems. The filters have advanced from the low pressure type to high pressure in semi-closed system such as the V-22 aircraft and closed loop system.A simplified Integrated Closed Environmental Control System (ICECS) has been developed in a joint U.S./Canada program to meet environmental threats. The initial effort demonstrates the advantages of the closed loop vapor cycle over an open air environmental control system. The payoff of ICECS results in estimated avionics/Life Cycle Costs reduction of up to 16.3%, lowered Take Off Gross Weight by up to 10% and a possible range increase of up to 15%. This paper will detail the ICECS effort and future directions as developed by the U.S. Air Force Wright Laboratory's Flight Dynamics Directorate.