Get on a plane, and carbon emissions aren't the only environmental problem to think about. Aviation fuel is the largest source of lead emissions, and Friends of the Earth is calling on the EPA to get it under control. The EPA identified at least 16 regions last month that do not meet clean air standards on airborne lead emissions, and just about every one of those regions contains an airport that allows leaded aviation fuel. Nearly 20,000 airports in the U.S. allow leaded fuel, which is said to contribute half of the nation's total lead air emissions. Marcie Keever, legal director of Friends of the Earth, which has been pushing the EPA to phase out lead from aviation since 2003, said : "The recent findings of clean air violations reinforce our concerns: Fifteen of the sixteen areas declared to have unsafe levels of lead in air are in counties that contain at least one airport where lead is emitted." ...Leaded aviation fuel is primarily used in piston en...