The National Science Advisory Board for Biosecurity has recommended the repeal of an amendment enacted by Congress two years ago that bans the synthesis of the smallpox virus, Variola. NSABB's mandate is to help the government devise safeguards against the illicit application of life sciences research. The board concluded that the amendment, which imposes a penalty of up to 25 years in prison for scientists who attempt to produce, synthesize, or engineer the virus, is too vague to aid the fight against bioterrorism and may actually hamper legitimate research. The amendment defines the pathogen as "any derivative of the Variola virus that contains more than 85% of the [virus's] gene sequence." Among other things, the board's working group on synthetic genomics, which recommended that the amendment be repealed, found the 85% sequence stipulation "arbitrary." Furthermore, the working group argued that misuse of the smallpox virus is adequately covered by other existing criminal legislation. The working group also recommended, and the full NSABB accepted, that the government overhaul its list of biological agents and toxins deemed a threat to public health—so-called select agents—because of advances in synthetic genomics. The working group argued that these advances make it possible to engineer functionally lethal agents that differ genomically from pathogens on the list.