We undertook to synthesize and experimentally determine the sporicidal efficacy against anthrax surrogate spores of two specific classes of novel energetic materials based on the general class of N,N-dihaloamine derivatives: organic N,N-difluoramine (NF2) derivatives and N,Ndichloramine (NCl2) derivatives. Sporicidal efficacies of gaseous detonation products from an N,N-difluoramine explosive, HNFX, were determined over a wide range of exposure times, ranging from milliseconds to seconds to hours. For exposure times less or equal to 1 second, observed log10-reductions of Bt were less or equal to 3. However, high killing efficacy (great or equal to 9 log-reductions) of anthrax surrogate spores was achieved by practically brief exposures (5 seconds or more) to gaseous products from detonations of HNFX. This agent defeat by HNFX was not due to heat or pressure of explosions but to harsh conditions of exposure to biocidal detonation products. The active sporicide was originally proposed conceptually to be hydrogen fluoride (HF), but other transient more-reactive halogen species may be involved. An example may be atomic fluorine or its by-products of reaction with spore materiel. Such transient reactive species may be unique to the class of N,N-difluoramines.