> - Catalytic converters & SCR (selective catalytic conversion) which injects corrosive DEF (Diesel Exhaust Fluid/ cow piss) into the exhaust. DEF is urea, yes

> - Catalytic converters & SCR (selective catalytic conversion) which injects corrosive DEF (Diesel Exhaust Fluid/ cow piss) into the exhaust. DEF is urea, yes, but that urea doesn't come from piss, it's synthetic - urea production was the first synthesis of an organic compound in fact, made possible at scale after the Haber-Bosch process was invented that produced the precursor ammonia.