Disease researcher testifies for Johnson & Johnson that talc powder does not cause mesothelioma

By John Sammon | Feb 22, 2019

ALAMEDA — A pathologist called as a witness by attorneys defending Johnson & Johnson—in a lawsuit accusing the baby powder maker of causing a woman’s mesothelioma—said on Thursday that talc powder does not cause the disease.

Attorneys for plaintiff Terry Leavitt attempted to show that Dr. Brooke Taylor Mossman did not possess the expertise to make such a judgement.

The trial in the Alameda Superior Court is being streamed live courtesy of Courtroom View Network.

Leavitt is suing Johnson & Johnson claiming the baby powder she used for 30 years beginning with her mother powdering her as an infant in the Philippines caused her to develop mesothelioma, a deadly cancer of the lungs. The disease, incurable and usually fatal within a few years of diagnosis, can take 30 years to turn into an illness. 

Michael Brown, the defense attorney for Johnson & Johnson, questioned Mossman, a professor specializing in pathology with the University of Vermont College of Medicine, on how mesothelioma forms in the human body.

“We’re paying you?” Brown asked.

“Yes,” Mossman said.

“What’s your rate?”

Mossman said $550 per hour.

“How much of your professional work is involved in litigation?”

Mossman estimated 50 to 75 percent of the time.

She explained that mesothelioma develops when asbestos fibers make their way through the bronchial tube to the air sacs of the lungs and the two pleural membranes. Because of their flexibility the fibers can lodge in the lungs in high concentrations.

The same flexibility of asbestos fibers that allows them to penetrate deep into the lungs also makes them valuable for use in building materials such as roofing.

Asbestos fibers in the lungs lead to what is called “gene expression,” where DNA switches on or off to create an abnormal cell. A healthy cell becomes a cancer cell.

Mesothelioma occurs if four conditions are present: oxidant release, protein receptors change, altered gene expression and abnormal cell proliferation. Mossman said that without the presence of all four conditions mesothelioma would not occur.

An issue during the trial and past asbestos trials has been the difference between a real asbestos fiber and a “cleavage fragment,” a broken-off piece of non-asbestos mineral that defense attorneys maintain can look like an asbestos fiber under a microscope and be mistakenly identified as such.

Brown asked Mossman if she agreed that non-asbestos cleavage fragments do not cause cancer.

“Yes that’s central to my opinion,” Mossman said. “I think we should emphasize that the talc I worked with were injected [in test animals] and did not give rise to cancer, so it was substantiated by our findings.”

Mossman said non-asbestos minerals have different properties than asbestos.

She also said talc powder could remain in the lungs for approximately eight years, according to a 2010 report by the International Agency for Research on Cancer (IARC).

“Talc does not cause mesothelioma?” Brown asked.

“Correct,” Mossman responded. “Talc has not historically been fibrous.”

Mossman said talc powder does not have the flexibility or tensile strength of asbestos.

Under cross examination, Moshe Maimon, Leavitt’s attorney, sought to undercut Mossman's status as an expert witness on asbestos exposure.

Talc for Johnson & Johnson baby powder had been mined in Italy, Vermont and more recently Korea. Maimon asked, “You’ve done no research on Korean talc, correct?”

“Correct,” Mossman said.

 “You’ve never done any literature review with regard to tremolite [an asbestos related mineral] in Korean talc?”


“You yourself have never studied talc bio-durability?" he asked, referring to the length of time talc remains in the body.

“That’s correct.”

“You’re not a medical doctor?”


“You’ve never been involved in the care and treatment of patients?”


“You’re not an epidemiologist, correct?”


Mossman explained that her job was to look at the interaction and reaction of minerals on human cells.

Mossman rejected Maimon’s assertion that she had not performed fiber measurements, saying that in the 1980s she had measured silicate minerals such as riebeckite and chrysotile, an asbestos-related mineral, with a colleague, studying their fiber size dimensions with a scanning transmission electron microscope (TEM) and publishing the findings.

However, studying aspect ratios of cleavage fragments as opposed to asbestos fibers, she said, was outside the scope of her work.

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