This manual is one of five that explains the fundamentals of NBC defense: FM 3-3, Chemical and Biological Contamination Avoidance; FM 3-3-1, Nuclear Contamination Avoidance; FM 3-4, NBC Protection; FM 3-5, NBC Decontamination; FM 3-7, NBC Handbook. A general overview of these fundamentals is given in FM 3-100, NBC Operations. This manual, FM 3-3, defines and clarifies the entire process of CB contamination avoidance. Another manual, FM 3-3-1, outlines contamination avoidance procedures for nuclear operations. FM 3-3 details the NBC Warning and Reporting System, how to locate and identify CB contamination, and how to operate in and around NBC contamination. This manual is designed and intended to be an easy-to-read, step-by-step manual depicting the manual method of calculating CB contamination avoidance procedures for chemical officers and NCOs. However, subject matter discussed in Chapters 1 and 2 and Appendices A and C are of general use for all branches and MOS.