Andreus writes:

We do come into contact with fuel so it is possible to meet up with a little
TEL, I'll worry when the high time pilots start showing symptoms.

In the case of heavy-metal poisoning, when symptoms appear it may be too late.
This is most true with very young victims, as the poisoning may cause
permanent neurological damage including mental retardation, blindness, etc.

Among adults, clinical manifestations of lead poisoning due to lead in fuel
have not been observed in the general population, as far as I know, but higher
lead levels in vivo for this population have been documented. The effects of
these higher but still low levels is indeterminate. What is known is that
young people are much more sensitive to this type of poisoning, and even if
adults are not significantly affected by it, children might be.

Thus, getting rid of the lead is a good idea. It will come to aviation in
time as well.