The U.S. Coast Guard Incident Management Handbook (IMH) is designed to assist Coast Guard personnel in the use of the National Incident Management System (NIMS) Incident Command System (ICS) during response operations. The IMH is intended to be used as an easy reference job aid for responders. It is not a policy document, but rather guidance for response personnel. During development of the IMH, it was recognized that eighty-percent of all response operations share common principles, procedures and processes. The other twenty-percent of response operations are unique to the type of incident, such as a search and rescue case or an oil spill. The handbook is laid out so that the generic information applicable to all responses is presented up-front. For example, the duties and responsibilities of the Planning Section Chief (PSC) are found in the generic section since a PSC's job description under ICS does not change from one type of incident to another. The remainder of the IMH is divided into eight types of incidents the Coast Guard is most likely to respond to. They are: Terrorism; Search and Rescue; Law Enforcement; Oil Spills; Hazardous Substance (Chemical, Biological, Radiological, Nuclear); Marine Fire Fighting and Salvage; Event Management and National Special Security Event (NSSE); Multi-Casualty. COMDTPUB P3120.17A.