• Role of Shorter Mineral Fibers in Causing Mesothelioma
  • November 26, 2015
  • Law Firm: Waters Kraus LLP - Dallas Office
  • Shorter mineral fibers — like chrysotile asbestos fibers — are toxic and should not be overlooked when studying the cause of mesothelioma and other lung diseases, believed Philip Cook, a former scientist with the U.S. Environmental Protection Agency (EPA).

    In the 1960s when Cook worked for the EPA in Duluth, Minnesota, he became involved in research concerning thin mineral fragments that appeared to be asbestos found in Duluth’s drinking water. Residents were frightened for their health and the city built a water filtration plant to allay their fears. Ultimately, the mineral fragments were found to have come from the Reserve Mining Company’s taconite processing plant located 50 miles upstream. The mining company was required to stop dumping its waste rock into Lake Superior and to create a disposal pond instead.

    An EPA chemist, Cook became fascinated with the mineral fragments and spent years studying their possible health risks to exposed workers and residents. Though Cook died before his work was complete, his research was recently presented at a Duluth symposium on elongated mineral particles.

    EPA Scientist Argued that Shorter Mineral Fibers May Be Toxic

    Cook conducted animal studies using rats to puzzle out how long-term exposure to mineral fragments could cause changes in the lungs. As he conducted his research, Cook became concerned that federal regulations governing air quality in the workplace required monitoring only for long, thin fibers and not for shorter fibers. Cook was convinced that the shorter mineral fibers acted to increase workers’ harmful exposures.

    In 1999, Cook was asked by the EPA to assess the risk to Libby, Montana residents and workers from a vermiculite mine contaminated with asbestos. An unusually high number of people in the area were dying from mesothelioma, a disease with only one confirmed cause — asbestos exposure.

    In working on the Libby mine case, Cook began to search for a way to identify which types of mineral fragments cause the greatest health risk. After studying 50 fiber types and testing over 200 different models, Cook became convinced that looking at a fiber’s size and shape was not the most reliable predictor of toxicity. According to Cook, a fiber’s total surface area was more important in evaluating its risks to health.

    In 2013, Cook died from cancer before he was able to publish the results of his work. But Cook’s boss at the EPA, Dr. Dale Hoff, undertook to carry on with Cook’s research, which reportedly was 98 percent complete. The resulting paper, arguing that small fibers contribute to toxicity, was recently presented at an October symposium in Duluth, “Asbestos-like Mineral Fibers in the Upper Midwest: Implications for Mining and Health Workshop.”