Distilling hydrocarbons involves adding so much energy to already flammable chemicals that they boil. What could go wrong?! Even processes like distilling water-alcohol mixtures result in a flammable distillate (think of cooking flambe'). In a practice problem, distilling benzene and toluene or hexane and octane seem like innocuous processes, but they require diligent adherence to process safety management. See the links below for examples.