Ancient Roman cosmetics were notoriously poisonous — despite the fact that it was already a well-known toxin, folks slathered their faces in white lead and dabbed red lead rouge on their cheeks. You wouldn't drop dead from a single application. The problem built up over time, as more and more and more of the stuff was applied (and absorbed) by your body. And that's still true today. In a new column for The New York Times — all about chemicals and your environment — Deb Blum writes about the lead (and aluminum and cadmium and all sorts of of other metals) that contaminates modern lipstick. The doses are low, much lower than Roman times. But the reapplications are many. Lipstick wearers touch up their color as often as 20 times in a single day.