Pathology expert witness for defense discusses mesothelioma from alleged workplace exposure


pathology expert witnessA pathology expert witness for the defense opines on a case involving a ninety-year-old man who died from malignant mesothelioma. He also had been diagnosed with T-cell lymphoma after exhibiting distinctive symptoms of swelling nodes and night fevers. Through the course of his life, the decedent spent time in the U.S. Navy, worked as an iron worker for more than forty-years and was employed at industrial sites including power plants and steel factories. At two of the power stations, the decedent’s coworkers regularly worked with pumps that had gaskets or packings containing chrysotile asbestos. Following his death, the decedent’s family asserted claims for wrongful death and strict products liability against the manufacturer of the pumps. They allege the decedent’s exposure to the asbestos-containing pumps caused the fatal mesothelioma.

Question(s) For Expert Witness

  • 1. Can chrysotile asbestos contained in pump packings become airborne and contribute to mesothelioma?
  • 2. Can working in the vicinity of chrysotile asbestos result in the disease?

Expert Witness Response

To a reasonable degree of medical certainty, any work the decedent may have done near the pumps or their gaskets and packings played no role in causing his pleural malignant mesothelioma. The pumps at issue may have contained non-friable chrysotile asbestos encapsulated in a resin matrix. The matrix limited the escape of free asbestos fibers, so that they did not enter workers’ breathing zones. Working with or near chrysotile-containing gaskets and packings would not produce exposure to chrysotile that exceeded Occupational Safety and Health Administration (OSHA) permissible levels. Additionally, exposure to dust in the air during work on gaskets and packings does not indicate inhaled or absorbed exposure in the lungs to asbestos, because not all dust particles are respirable or capable of entering the lungs. The upper respiratory tract acts as a natural defense against chrysotile fibers. The mucus and other defense mechanisms remove the fibers from the airway before they can enter the lungs. The lungs then have further defenses that digest the chrysotile fibers. This limits the ability of the fibers to cause malignant mesothelioma.

All of these factors — the encapsulation in the resin matrix and the body’s defense mechanisms — would have limited the exposure to a negligible or background exposure to chrysotile. Chrysotile asbestos fibers have limited potency to cause malignant mesothelioma, particularly compared to amphibole forms of asbestos. Thus, the defendant’s pumps and their gaskets and packings played no role in the cause of the decedent’s disease.

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