Answer: Lawyers representing women who claimed talc caused them to develop ovarian cancer, sued Johnson & Johnson several times, originally unsuccessfully.

In the original court cases, the lawyers claimed that talc, the mineral talc itself free of asbestos, was carcinogenic and it caused ovarian cancer among the women they represented. However, they weren't successful, as there was, and still is, relatively little supporting medical evidence that uncontaminated talc is carcinogenic.

The lawyers were undaunted, and tried again after they learnt that some talc mines Johnson & Johnson sourced its talc from were contaminated with Termolite or Actinolite, a pair of related minerals (actinolite is magnesium rich, tremolite is iron rich) that sometimes, under certain geological conditions, can form tiny long thin fibrous crystals. If they form thin fibrous crystals, they are termed Asbestiform i.e. Asbestos, a respirable fibre.

This case signals a change in the litigation surrounding talc product-induced ovarian cancer in Missouri by placing the blame on potential “contaminants” of talc, rather than the talc itself. - Casey & Larkin, 2019.

(Asbestos is a crystal shape, not a mineral, several minerals can form asbestiform crystals, actinolite is just one of these. The long thin crystals can enter the body and cannot be expelled, over many years the irritation they cause can lead to cancer, mesothelioma of the lining of the lungs, and ovarian cancer).

Deciding if actinolite-tremolite is asbestiform requires careful analysis, using specialist tests, including a transmission electron microscope to measure the crystal's dimensions.

According to Johnson & Johnson, their testing ensured talc that contaminated with actinolite did not contain asbestiform fibres.

However, asbestiform actinolite-tremolite is a well established carcinogen, and this factor helped overrule J&J's reassurances that its testing ensured actinolite wasn't asbestiform, so at retrial the Jury decided that talc contaminated with actinolite was the cause of the women's ovarian cancer. The 22 women were awarded $550 million in compensatory damages and $4.14 billion in punitive damages, a $2 billion portion of this award was upheld in 2021.

The decision was controversial at the time, with several experts expressing the opinion that the link was weak. Some also criticised the tactics of the lawyers, arbitrarily switching focus from talc to actinolite.

Critics also claimed the jury's decision was at variance with studies that failed to find any cases of mesothelioma among talc miners, were there was actinolite contamination.

On the other hand, subsequent research vindicated the jury's decision. Analysis of ovaries from women who died or were treated for ovarian cancer, found asbestos fibres in their tissue, a worrying finding.

It appears that the grinding process can generate asbestiform actinolite and that J&J testing was inadequate. Their testing did not ensure talc was fully free of asbestiform actinolite. This would explain why talc mine workers didn't develop mesothelioma, they weren't exposed to milled talc.

Additionally, it is now clear that J&J spent decades hiding a link between contaminated talc and ovarian cancer. Shockingly, J&J commissioned a study into the possible link between asbestiform actinolite and ovarian cancer, in the 1970s, it confirmed earlier findings, but J&J buried the report:

For example, in 1971, Henderson et al. found talc in an ovarian cancer tissue sample and raised concerns about the relation between talc use and ovarian cancer. Johnson & Johnson hired Arthur Langer, a mineralogist at Mount Sinai, to reexamine the tissue. Langer confirmed the presence of talc, and also found asbestos in ovarian cancer tissue. Evidence shows that Johnson & Johnson successfully dissuaded him from publishing these findings.

Reference:

Casey, R. and Larkin, T.P., 2019. Ovarian Cancer and “Tainted Talc”: What Treating Physicians Need to Know. Missouri Medicine, 116(2), p.83.

Tran, T.H., Steffen, J.E., Clancy, K.M., Bird, T. and Egilman, D.S., 2019. Talc, asbestos, and epidemiology: corporate influence and scientific incognizance. Epidemiology (Cambridge, Mass.), 30(6), p.783.t

When I was a PhD student, one of the undergraduate students in my geology department did a 3rd year project on talc, almost all samples tested positive for actinolite. However, I don't recall if they tested it to see if it was asbestiform. That was likely too advanced.