The methodology of HSEEP was based on proven exercise design, development, and evaluation methods from other programs. There are three exercise programs that had a significant influence on HSEEP during its development. These programs include the following: (1) Chemical Stockpile Emergency Preparedness Program (CSEPP). The key ties to HSEEP are the recognition of increased hazards associated with critical infrastructure and hazardous materials and contribution of evaluation methodology. (2) Radiological Emergency Preparedness (REP) Program. The key ties to HSEEP are that REP was the first major exercise program to involve local first responders in biannual exercise activities and that it helped contribute to the evaluation methodology. (3) Nunn-Lugar-Domenici (NLD) Domestic Preparedness Program. The key tie to HSEEP was that NLD was the springboard to the NEP and was the first program to recognize an increased hazard in the Nation's urban centers. It contributed many of the lessons learned and best practices for the design and development methodology. (FEMA, About HSEEP, 2008)