The NBACC was created as a federal response to the anthrax letter attacks in 2001 as the first national laboratory operating under the Department of Homeland Security. The Department of Homeland Security said the mission of the NBACC is "to provide the scientific basis for the characterization of biological threats and bioforensic analysis to support attribution of their planned or actual use." Part of the NBACC's mission is to conduct realistic tests of the pathogens and tactics that might be used in a bioterrorism attack. It seeks to quantitatively answer questions pertaining to what might happen in a biological attack. This work is carried out by about 180 researchers and support staff and has become more advanced since the NBACC became certified to work with biological select agents and toxins in September 2011.