Why is the FAA just now initiating studies regarding avgas Pb issues. Has this not been on the table for about two decades? It would seem logical that if such actions are to be taken such as banning Pb in avgas, there should be a sound scientific basis including exposure dose response issues, not whether there might be a minuscule amount in the environment from who knows what origin. And please no hysterical knee jerk comments about how bad Pb is since it is totally dose response related and the potential dose from avgas exhaust does not even register.