Bacillus atrophaeus has historically been grouped with B. subtilis, and is usually described as a black-pigmented variant (var. niger) because of its many phenotypic similarities to the bettercharacterized B. subtilis. Both organisms are soil-dwelling, nonpathogenic saprophytes, but have been differentiated by the ability to produce pigment on nutrient media containing an organic nitrogen source [13] . The orange pigmentation of B. atrophaeus var.globigii spores made it an attractive simulant for B. anthracis, facilitating the detection of dispersed spores in complex environmental samples. Recently, more sensitive phylogenetic approaches using AFLP have delineated B. atrophaeus as a separate species [13, 14] . The taxonomic confusion has arisen due to inadequately sensitive typing methods, and has led to misattribution of pathogenic qualities associated with some B. licheniformis strains to the B. atrophaeus strains currently in use as simulants [12] , for which no direct evidence of pathogenicity exists. This report defines the genomic composition of B. atrophaeus var.globigii and clearly separates the species by wholegenome phylogenetic analysis.