This is why 100LL has had such an extended stay despite it's unfriendly environmental footprint.
There's absolutely no evidence that lead in motor fuel ever caused any real harm it was banned 'cos some environmental lobbyists in the US discovered that lead is a cumulative poison and did an extrapolation that was utter nonsense, but succeeded in getting unleaded and catalytic converters mandated. This combination is more environmentally unfriendly than any leaded solution due to poorer fuel consumption and the toxic heavy metals in CATS.
For what it's worth my generation probably ingested more lead from chewing the paint off our cots when we were babies
There is even less of a case for banning 100LL since the volumes are so low its environmental impact is negligible. However the same lobbyists are riding the same hobby horse so the same stupid outcome seems inevitable.
