5000 year of experimentation ain't worth shit if isn't written down and organized so the data can be analyzed.

You've got 5000 years of anecdotes, which is worth as much as the shit I'm taking right now compared to actual science.

Using lead in pipes, plates, paint for 1000s of years certainly wasn't an issue for many and more recently in our history leaded gasoline.

As for tattoos it's not all rainbows and unicorns as I have younger family members that have developed issues from their tattoos and have looked into removal but decided while visually they do appear mostly to not be visible they are not completely gone from under the skin so they decided there's no reason to go through with the pain in their case.

I also have senior family members with with tattoos from their youth on their legs and arms that haven't caused them issues besides having whatever they started out with just look like a hazy blue blobs now so their experiences should be the only ones that count.

It does seem like the latest laser removal technology employed by medical professionals can now eventually remove most of the colors now with less scarring where the initial older lasers struggled with all the colors.

Here is a FDA link to some of the issues for with tattoos for some: https://www.fda.gov/consumers/consumer-updates/think-you-ink-tattoo-safety

This is the link the photo is from: https://www.webmd.com/skin-problems-and-treatments/laser-tattoo-removal

This article breaks down the advances, long time lines for removal, and the potential issues of removal that can arise: https://www.glamour.com/story/tattoo-removal-cost-what-is-it-like

But yes like how safe lead is, tattoos it's all good. Rainbows and unicorns my friends.... /s