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_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.

Slow down there.

Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils...

I have no idea - but my anecdata point relates to a school friend who converted a van. It smelt like a fish and chip shop from a fair distance. It ran great until the home-brew water injection failed. It was parked on a slope and the water filled the cylinders. Turning it on was a rather violent attempt at compressing water.

Unfun fact, the person who invented tetraethyl lead gasoline additive also invented chlorofluorocarbons.

https://en.wikipedia.org/wiki/Thomas_Midgley,_Jr.

Why is it unfun? Is he evil for inventing things that later turned out to be harmful?

Apparently he indeed was evil: "On October 30, 1924, Midgley participated in a press conference to demonstrate the apparent safety of TEL. In this demonstration, he poured TEL over his hands, then placed a bottle of the chemical under his nose and inhaled its vapor for sixty seconds, declaring that he could do this every day without succumbing to any problems whatsoever. Midgley himself was careful to avoid mentioning to the press that he required nearly a year to recover from the lead poisoning brought on by his demonstration at the press conference."

I believe the grandparent was merely stating a piece of possibly interesting but not particularly useful knowledge that might normally be labelled a "fun fact", but didn't want to use the word "fun" when mentioning inventions that caused thousands of deaths.