The dangers of kohl eyeliner

Kohl served multiple roles in Egyptian antiquity. Egyptians of all social classes applied the eyeliner daily in veneration of the deities, satisfying both religious obligations and beautifying desires. Wearing the glossiest, highest quality kohl denoted one’s upper class status in society while the less wealthy adulterated their kohl with fire soot. Before the advent of Ray-Bans, it was applied liberally around the eyes to reduce the sun’s glare, to repel flies and to provide cooling relief from the heat. It also trapped errant dust and dirt, a simple remedy to curb the desert’s regular assaults on the body...

Kohl is predominantly composed of the mineral galena, a dark, metallic lead-based product that is also known by the chemical name lead sulfide (PbS). The mineral would be crushed and mixed  with several other ingredients such as ground pearls, rubies and emeralds, silver and gold leaves, frankincense, coral, and medicinal herbs such as saffron, fennel, and neem...

A 240-fold increase in NO production was sparked by the presence of lead ions, a bona fide tsunami of molecules flooding surrounding cells to respond to invading bacteria. This intense biochemical interaction suggests that kohl was more than just a beautifying cosmetic and the forefather of sunglasses, but also an important antibacterial ointment...

Kohl is still used today in North Africa and Central Asia, despite its considerable toxicity.

There is more information about the toxicity at NPR:

Two Afghan children now living in Albuquerque developed very high levels of lead in their blood because of eye makeup, health workers reported Thursday in Morbidity and Mortality Weekly Report.

The family had just emigrated from Afghanistan as refugees. And they brought the traditional eyeliner, called kajal, with them...

When health workers tested the kajal in the family's home, the eyeliner turned out to be 54 percent lead. That's 540,000 parts per million, or 27,000 times the cap set by the Food and Drug Administration for color additives in makeup.

Lead is a neurotoxin. And it's especially harmful to babies and young children. Even small amounts can damage developing brains and cause permanent problems.