Talcum powder, a seemingly innocuous, everyday household product for well over a century, has turned deadly for some users. Specifically, for the women who have found themselves victims of ovarian cancer as a result of using talcum powder in the genital region. What manufacturers have known (or should have known) for at least 45 years is that the substance can cause chronic inflammation – a condition that medical science has connected with the development of some types of cancer.

Talcum is actually comprised of different inorganic minerals, primarily magnesium, silicon and oxygen. Prior to the 1970s, some talcum products also contained asbestos, a naturally-occurring mineral and known carcinogen. Although talcum products have been asbestos free since that time, researchers noted talcum’s chemical similarity to asbestos. Like asbestos, talc is a silicate mineral, having a crystalline structure. When ingested, these minerals have been known to cause irritation, leading to the chronic inflammation that can lead to the formation of cancerous tumors. In 1971, British researchers did analyses of 13 ovarian tumors, discovering that talcum particles to be “deeply imbedded” in 10 of the cases. Eleven years later, another study at the Brigham & Women’s Hospital in Boston demonstrated a clear statistical link between the use of talcum powder and ovarian cancer.

These and several subsequent studies indicate that when applied to the genital region, talc particles can migrate up the vagina, into the uterus and Fallopian tubes, causing an interaction with female hormones in a way that activate antibodies. Known as macrophages, these white blood cells identify talc particles as invaders and begin to ingest them. This is what leads to the chronic inflammation associated with certain types of cancer. Today, the International Agency for Research on Cancer (IARC, part of the World Health Organization) has placed talcum in its 2-A classification, identifying it as “possibly carcinogenic to humans.”

Over the past three decades, dozens of studies on this issue have been published, and all of them have demonstrated some connection between the use of talc and an increased risk of ovarian cancer. Amazingly, gynecologists and others in the medical profession have only recently come to be aware of it.

It should come as no surprise that industry players have been denying any association between talcum products and cancer. Johnson & Johnson, once the “Most Trusted Brand in America,” started sales of its Baby Powder in the 1890s. In those days, many analgesics consisted of plasters applied to the skin, which left irritating rashes when removed. Initially, talcum powder was intended to relieve the discomfort from these rashes. Consumers soon reported that the product was effective in the treatment of infant diaper rash as well.

J&J’s Baby Powder is 99.8% talc, which is combined with various fragrances. As many marketers of consumer products will tell you, scents can be very evocative. One J&J executive told the press several years ago, “It’s calming, nurturing. … It doesn’t grab your senses. It wafts.” Interestingly, Baby Powder is not J&J’s biggest seller, accounting for a mere $374 million in sales in 2014. Considering that J&J is a $70 billion corporation, that figure doesn’t amount to much. However, over the past century, that single product has led to the development of an entire line of infant products, including Baby Oil and Baby Shampoo. J&J’s baby division today accounts for approximately $2 billion in revenue.

Epidemiologist Daniel Cramer, who led the first study showing a statistical link between the genital use of talcum and ovarian cancer, said that soon after the study was published, he received a call from a J&J executive who spent a great deal of time trying to convince him that “talc use was a harmless habit.” Dr. Cramer says, “I don’t think this was a question of money. I think it was pride of ownership. Baby Powder is a signature product for J&J.”