Sunset for Leaded Aviation Gasoline?

F lying in a small piston-engine plane bears little resemblance to flying in a commercial jet. There are no lines at the airport, no baggage checks, and often less legroom once you duck inside the cabin. You can feel every bump in the tarmac as the plane heads down the runway, every rumble of the engine. Once you are aloft there's no denying the improbability of flight; the low cruising altitude offers detailed views of the land passing below. The experience is more like traveling in an airborne car than in the insulated cocoon of an airliner. For passengers like this writer, it's also much more fun. There's another less obvious difference. Unlike commercial jets, which use kerosene-based jet fuel, piston-engine aircraft still mostly run on leaded aviation gasoline, or avgas. In fact, avgas is one of the few fuels in the United States that still contain lead, 1 leaving it the single largest source of lead emissions in the country, according to the U.S. Concern over the health effects of lead has sparked a contentious effort to finally get the lead out of avgas—something the aviation and petroleum industries have been attempting for more than two decades, to no avail.