https://journals.sagepub.com/doi/10.1177/0960327117737146 Classical knowledge that lead exposure could result in poisoning:
"Nicander (Floruit (fl.) second century B.C.E.) has been credited as writing the earliest recorded account of lead poisoning during the second century B.C.E.10 Dioscorides (circa (c.) 40 to (c.) 90 C.E.) also described a case of lead poisoning in the first century C.E.11 Pliny wrote about the dangers of red lead and lead acetate.12 Celsus (c. 25 B.C.E to c. 50 C.E.) also identified lead as a poison and proposed an antidote consisting of walnut juice combined with wine.13 Galen (130 to c. 210 C.E.) previously stated that water transported to Rome through lead pipes was not suitable for consumption.14 Galen also recommended that rain water should be used in the preparation of medicines, as opposed to water brought through lead pipes.14 Vitruvius (c. 80 to c. 15 B.C.E.) wrote about the health implications of using water collected from lead pipes.14 Aetius (c. 390 to 454 C.E.) also wrote about the dangers of collecting rain water from roofs, as roof tiles were often covered with lead.14 Both Vitruvius and Pliny (23 to 79 C.E.) identified that the fumes from lead mining were poisonous; Vitruvius goes further to state that water near mines was also found to be harmful.12,15 Pliny describes how the lining of copper pots with lead prevents the leaching of copper into food.3 Marcus Cato (234 to 149 B.C.E.) and Columella (4 to c. 70 C.E.) also promoted the use of lead and lead-lined vessels.16,17 Pliny, Marcus Cato, and Columella all endorsed the boiling down of grape syrup in lead vessels as part of wine production.12,16,17 The addition of lead as a sweetener to wine was described by Pliny.12 Pliny also described that heavy consumption of lead-sweeten wine could result in paralysis in the hands.11 Similarly, Diodorus (90 to 30 B.C.E.) described these wines as capable of leading to pain in the nerves.18 Paul of Aegina (c. 625 to c. 690 C.E.) described an epidemic of lead poisoning that occurred in Ancient Rome during the seventh century C.E.19 Herodotus (c. 484 to c. 425 B.C.E.) describes that lead was used in the bridges of Babylon, and Diodorus Siculus mentions that lead was incorporated into the Hanging Gardens of Babylon.17,20 Another ancient practice with lead commonly seen in Ancient Greece and Anatolia was a practice where molten lead was mixed with water and the forms and shapes produced would be examined to predict the future.21,22 These practices were often conducted indoors with minimal ventilation"
The link has a number of other examples where lead was determined to be poisonous leading. (including spontanous abortion and sterility.)
The issue is an issue of will, not knowledge. Lead has legitimate uses, but plumbing and eye makeup or paparika coloring are not among them!
EXCELLENT post, Pete!