EPA is starting a new crusade. This time they are going after lead weights (tire balance), I guess they already have gotten the lead out of many shot gun shells, premature ruin of a good gun barrel when using steel shot - I think it was to prevent fish from getting too much lead from duck, bird hunters shooting over lakes.
The idea is disposal of used lead weights is unregulated and the way they are thinking now - any lead in the unregulated enviroment is too much. I haven't heard of what is supposed to replace lead weights, but when it somes to Government, planning is what you do - after you spend the money. 
So, no more lead weights used to balance tires.