The talc they were sourcing was riddled with asbestos, which they covered up for years. Asbestos’s carcinogenic nature is unique in that the physical shape of the fibers is what causes the cancers. So many of the cancers implicated here were due to the typical path of women breathing the powder in while applying to their babies, etc, but the ovarian ones were likely caused by women applying talc to their perineum following birth or surgery - the asbestos fibers would be introduced into the vagina and ‘burrow’ into the cells where they cause similar cancers to mesothelioma or actually interfere with mitosis due to being similarly sized to chromosomes.

It’s not too far fetched since the uterus and lungs are both lined with similar types of epithelial and mucosal cells.