New data from DuPont and BP, based on ongoing laboratory-based engine testing and limited fleet testing, indicate that biobutanol performs similarly to unleaded gasoline on key parameters. The companies are working to deliver advanced biofuels that help meet increasing global demand for renewable transportation fuels. The first product targeted for introduction is biobutanol. Early phase testing data show that the energy density of biobutanol is closer to unleaded gasoline. Also, fuel testing has proven that biobutanol does not phase separate in the presence of water and has no negative impact on elastomer swelling.