Does Talc cause Cancer?

The World Health Organization's cancer agency (IARC)  classified talc as "probably carcinogenic" for humans.

Talc is a mineral made up mainly of magnesium, silicon, and oxygen. As a powder, it absorbs moisture well and helps cut down on friction, making it useful for keeping skin dry and helping prevent rashes. It is widely used in cosmetic products such as baby powder and adult body and facial powders, as well as in a number of other consumer products. Talc is mined from the earth. In this natural form, some talc contains asbestos, a substance known to cause cancers in and around the lungs when inhaled.

When talking about whether talcum powder is linked to cancer, it is important to distinguish between talc that contains asbestos and talc that is asbestos-free. Talc that has asbestos is generally accepted as being able to cause cancer if it is inhaled. The evidence about asbestos-free talc is less clear.  Talcum powder might cause cancer in the ovaries if the powder particles (applied to the genital area or on sanitary napkins, diaphragms, or condoms) were to travel through the vagina, uterus, and fallopian tubes to the ovaries. 

The published results of many study explain that: "It was not possible to fully establish a causal role for talc." Their aim is not to alarm, but only to answer the question of whether this substance is really carcinogenic.This means that although there is limited evidence that it can cause cancers in humans (especially ovarian cancers), there is sufficient certainty that it causes cancer in experiments. This means that talc can have characteristics of carcinogens in human cells and experimental systems.