There is no good level for lead exposure. It is always bad. If anything, I think the FDA should make their limits more strict. Yet the FDA is slow moving and susceptible to a lot of industry influence that wants no regulation.
The good news is that if and when we eliminate lead totally from its remaining uses, we won't have to wait too long to see the benefits. IIRC people's blood lead levels started dropping pretty quickly after we phased out leaded gasoline.