From Wikipedia: "Biodiesel is the only alternative fuel to have successfully completed the Health Effects Testing requirements (Tier I and Tier II) of the Clean

From Wikipedia: "Biodiesel is the only alternative fuel to have successfully completed the Health Effects Testing requirements (Tier I and Tier II) of the Clean Air Act (1990)." https://en.wikipedia.org/wiki/Environmental_impact_of_biodiesel https://en.wikipedia.org/wiki/Environmental_impact_of_biodie... Either way the tetraethyl lead situation was completely different. It was very clear early on that the stuff was extremely toxic. Lead was already known to be toxic, and workers at the refineries were dying left and right due to exposure.