1. Typical car has about 2 tons of iron and about a pound of wheel weights.
2. MLDO (minimum reported lethal dose) for lead is 1470mg/kg. Here is a link. For a 10kg child this is 14,700 mg.
3. The reported MLDO for iron is 600 mg for a child. Here is a link.
Iron seems to be about 25 times more dangerous than lead. Iron parts of a car bring 100,000 times more poisoning danger than wheel weights.
I do not buy arguments on lead wheel weights ban before banning the iron.