The Greeks used it to construct building materials. The Romans used it to clean up blood after gladiator contests. King Charlemagne is said to have sprinkled it in with egg whites to keep his hair stiff and glistening on the battlefield, a sort of ancient-school mousse. Yes, talc has been used in one way or another for centuries. Besides being the main ingredient in baby powder, these days talc can be found in everything from flea and tick powders to deodorants, chalk and crayons, soap, and circuit boards. It's used in home insulation material and as filler in paper. Ceramic tiles contain talc, as do paints and even some of that dust you find on certain sticks of chewing gum.
For a mineral (pure talc is hydrous magnesium silicate) found in so many products, you'd think it would be as safe as salt. And generally it is. But guess what? Not only is the talc silicate related to deadly asbestos, some talcum powders are sometimes contaminated with asbestos. The result? Lots and lots of studies. The result of all the studies? Mixed.
However, in 1982, Johnson & Johnson admitted that they knew of some of these studies that concluded that woman who frequently applied talc products to their genitals had a three-fold increased risk of ovarian cancer.
(from August 12, 1982 New York Times article).
Other studies show that, since the 1980s, several thousand infants have died each year, or became seriously ill after accidentally inhaling baby powder. Many scientists have asked the Food and Drug Administration to require talc products to carry warning labels, something the FDA has yet to agree to. While other studies have not proven a link between talc and cancer, to play it safe, many people recommend using a mixture of cornstarch and baking soda as an alternative. Or get your hands on some natural baby powder in a health food store, usually made with things like green clay, tea tree oil and lavender or chamomile.