Experiments have been performed to determine the blowout of jet diffusion flames with pure fuels, oxygenated fuels, mixed fuels, and diluted fuels. Stability tests were conducted with pure hydrocarbons at the C-2 level to determine the effects of structural differences in the fuels. Diffusion flame blowout models were also used to correlate and interpret the data. Ethylene is more stable than ethane because of the additional heat release from the double-carbon bond and ethane is more stable than dimethyl ether. The blowout pressures of mixtures of ethylene and ethane are not linear contributions of component blowout pressures. Stability tests were conducted with ethylene diluted with air and nitrogen. Since both diluents have similar properties and also have a similar density to ethylene, factors in the blowout process, such as the laminar flame speed and air-fuel mass ratio, were isolated and measured. Stability tests with hydrogen diluted with helium, nitrogen, carbon dioxide, and sulfur hexafluoride were also conducted. The diluted hydrogen diffusion flames become less stable as the complexity of the diluent increases. (C) 2013 Elsevier Ltd. All rights reserved.