Harmless ceramic form. The real reason they got rid of it was so they could sell much dirtier gasoline and make up for it with a catalytic converter, which the lead compounds would ruin.
>>20086576 dig moar
THE LIES OF UNLEADED PETROL
Compiled by Catherine Simons, B.Sc.
From articles by Peter Sawyer, Graham Allum and Simon Grose, as published in
NEXUS Magazine, Volume 2, #25 (April-May '95).
http://www.whale.to/b/simons.html
We stopped using lead in water systems around then. Lead solder somewhat later.
The specific outweighs the general.