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Medical Experts And Federal Agencies Agree: Each Exposure To All Asbestos Fiber Types, Including Chrysotile, Cause Meso


Does chrysotile asbestos cause mesothelioma? Yes. Even the asbestos company defendants today largely agree with that simple, irrefutable truth. Their strategy, instead, has been to persuade the Judge to prevent the plaintiff from bringing to trial medical experts to testify about causation without first producing job-specific epidemiology studies that shows an elevated risk of disease among workers exposed to chrysotile fibers only. Neither medical science nor the law requires such a showing.

The following is a review of the opinions, based on reliable science, of four experts who have testified on the issue of whether chrysotile fibers from friction and clutch products cause mesothelioma among automobile brake workers. They also address the contrived defense "issue" whether epidemiology showing general causation (i.e., does the group of, say, auto mechanics have an increased risk of disease?) is a prerequisite to allowing in evidence of specific causation (i.e., did this plaintiff's exposure to defendant's chrysotile containing brake product help cause his meso?).

The Experts:

  • Dr. Richard Lemen, Ph.D
  • Dr. Arthur Frank, MD
  • Dr. Sam Hammar, MD
  • Dr. Ron Dodson, Ph.D

Dr. Richard Lemen, PhD

Dr. Richard Lemon, Ph.D. is an epidemiologist and former Deputy Director of NIOSH and Assistant Surgeon General.

Dr. Lemen has testified as follows in cases in which the plaintiff with mesothelioma was exposed to brake and friction products:

  • Epidemiological studies are not needed for every occupation and every type of exposure because asbestos is the known cause of disease. The amount of exposure determines whether disease occurs.
  • Those who work with asbestos containing friction products are at risk of developing asbestos diseases.
  • Many factors make it difficult to do epidemiological studies to show risk, including, but not limited to the difficulty of bringing together a heterogeneous group of brake workers because they suffer from different confounders.
  • The more the accumulation of the asbestos exposure, the greater the risk of asbestos disease. All fiber types cause asbestos disease. Brief exposure to asbestos can cause disease. Friction products release chrysotile fibers in an amount and size that are capable of producing asbestos disease.
  • Exposures vary from individual to individual, and one must look at it on an individual basis to determine risk for a particular person.

Dr. Arthur Frank, M.D

Dr. Arthur Frank is a toxicologist, who attended medical school at Mt. Sinai School of Medicine while Dr. Irving Selikoff was conducting his landmark studies concerning the hazards of asbestos and assisted with that work. Dr. Frank has testified as follows in brake cases:

  • There are a number of factors that clearly point to the relationship between exposure to asbestos from brakes and the development of asbestos disease.
  • There is scientific literature that the type of asbestos found in brakes, chrysotile, has the ability to produce all asbestos diseases including mesothelioma, lung cancer and asbestosis.
  • As is true for all carcinogens, each and every exposure to asbestos carries risks. As the exposure levels increase the risk of developing disease increases.
  • Dr. Frank helped examine the individuals seen in the Lorimer study. With the detailed occupational histories obtained and the X-ray findings, the only tenable diagnosis was asbestosis. For many of the cases the only reasonable explanation for the asbestosis was brake and clutch work.
  • The report by Nicholson et al (1982) documents the hazards of asbestos to brake mechanics. There were reports of fiber counts up to 72 f/ml reported by Rohl, et al., and the measurements by Nicholson show concentrations above background.
  • There is a greater prevalence of X-ray abnormalities in mechanics who repair brakes than among controls or mechanics who do not engage in brake work.
  • Epidemiological studies are not necessary for each and every group exposed to asbestos in order to opine that asbestos causes disease. One basic principle in all of occupational and environmental medicine is that the hazardous material is the issue, not the job category. The human body has the same response to inhalation of asbestos, regardless of one's occupation.
  • The position that a twofold excess in a specific group is required is unsubstantiated. There has been scientific documentation that there is a greater than twofold excess for mesothelioma, lung cancers, and asbestosis following exposure to asbestos.
  • Much of the epidemiological literature on brake mechanics has serious inaccuracies, including the use of gross terms like "motor mechanics," which do not always describe those doing brake repair.
  • While it is true that some brake materials is altered into fosterite during wear, there is still a significant amount of asbestos. For those doing brake repair, who regularly handle, grind and drill brand new brakes, extremely high levels of exposure can occur.
  • Even under the strictest rules that have ever existed, the Occupational Safety and Health Administration (OSHA) has concluded that additional cases of mesothelioma and lung cancer will occur.
  • Fibers from brakes have the same biological activity as fibers from other sources and can be additive in causing disease. Exposure to asbestos from brakes can cause asbestos related disease.
  • Brakes should not in any way be considered an inconsequential source of asbestos, or in any way, not capable of producing significant disease.

Dr. Samuel Hammar, MD

Dr. Samuel Hammar, M.D. is a pathologist, who is member of the elite U.S./Canadian Mesothelioma Panel and a member of a World Health Organization panel on lung tumors. Dr. Hammar has testified as follows:

  • An exposure level of .1 fiber cc years or less can cause mesothelioma.
  • Elliott McCaughey and Arthur Langer published a paper describing a 56-year-old man who was a career-long brake worker who died from mesothelioma. The only type of asbestos found in his lung tissue was chrysotile asbestos.
  • Based on the data that has been published on the amount of fibers that are released during brake work, one can conclude that this work is a contributing cause of mesothelioma and other asbestos diseases.
  • Even though there may not be any published epidemiological evidence that exposure to asbestos from working as a brake mechanic causes an increased incidence of mesothelioma, there have been 174 cases recorded.
  • If one has mesothelioma, one has been exposed to asbestos. Calcified pleural plaques are independent evidence of exposure because if the plaques are grinded and viewed through an electron microscope, they contain asbestos.
  • Tissue burden analysis involves counting asbestos fibers in the tissue and comparing it to a control population of people that do not have mesothelioma. If the fibers found are in excess of background levels, it demonstrates that mesothelioma was caused by asbestos. If both amocite and chrysotile are found at levels above background in the lung tissue, then both are causal.
  • Dr. Hammar co-authored a paper with Dr. Dodson entitled Asbestos in Extrapulmonary Sites. They discovered that when one finds asbestos in the peritoneal lining, it tends to correlate with having asbestos fibers of the same types in the lungs. Dr. Hammar has found chrysotile, amocite and crocidolite in the peritoneum and found the same fibers in the lungs.
  • If one has chrysotile in the peritoneum, he will likewise have a substantial amount of in his lungs.
  • Chrysotile goes to the pleura where the mesothelioma develops.

Dr. Ronald Dodson, PhD

Dr. Ronald Dodson is a cellular biologist at the University of Texas Health Center in Tyler, Texas. Dr. Dodson has testified as follows:

  • Tissue burden analysis provides information with regard to the number and type of asbestos fibers that are in the tissue.
  • The asbestos fibers typically used in friction products are not usually as long as eight microns. Thus, in looking at the fiber burden created by friction products, the light microscope is not a sensitive. The most sensitive tool for analyzing asbestos fibers is the transmissions electron microscope. It is possible to look at lung tissue with a light microscope and not see any asbestos bodies, but then look at that same tissue with a transmission electron microscope and see chrysotile fibers in levels above background.
  • Short fibers are removed more easily than long ones, and chrysotile fibers from brake products are more characteristically short. In being cleared from the lungs, chrysotile fibers can be dispersed into other areas of the body, including, but not limited to the linings of the lung and lymph nodes.
  • Mesothelioma is a cancer of the serosal membranes, the pleural lining of the chest cavity, the lining of the abdominal cavity or the lining around the heart. Generally, short fiber is most readily transported from the lung to the pleura where mesothelioma occurs.
  • Chrysotile can fragment and create shorter more respirable fibers.
  • In attempting to count the number of asbestos fibers that are actually present in the tissue of a person, and only counting fibers that are 5 microns in length, one can miss up to 95 percent of the fiber burden. One could essentially overlook all of the chrysotile. Because shorter fibers carry with them a risk of producing disease and pathogenicity, it is important to include them in the count.

Federal Agencies Agree: Chrysotile Causes Meso

OSHA has determined that chrysotile asbestos is a Human Carcinogen.

See e.gReport on Carcinogens, Public Health Service, National Toxicology Program (2004), 11 th Ed., Exhibit 2; Dept. of Labor, OSHA, Fed. Reg., Vol. 51, No. 119, June 20, 1986, Rules and Regulations, pg. 22615,

Federal agencies have issued recommendations and regulations restricting the use of asbestos based upon determinations that such products emit concentrations of asbestos capable of causing disease. The U.S. Department of Health and Human Services unequivocally states, "[a]sbestos and all commercial forms of asbestos are known to be human carcinogens based on sufficient evidence of carcinogenicity in humans." Rpt. on Carcin. 11 th Ed., Ex. 2.

OSHA states that it "is aware of no instance in which exposure to a toxic substance has more clearly demonstrated detrimental health effects on humans than has asbestos exposure." Fed. Reg., Vol. 51, No. 119, p. 22615, Ex. 3.

Government Agencies: Asbestos Brake Dust Causes Meso

In 1975, the Center for Disease Control issued a bulletin alerting recipients "to recently gathered information indicating a potential health hazard for persons exposed to asbestos during the servicing of motor vehicle brakes and clutch assemblies." Exhibit 4 ("a review of the scientific literature on the association between asbestos exposure and mesothelial tumors…has revealed at least four cases of these rare tumors in persons who were employed in jobs involving automobile brake servicing"). This bulletin concludes, "[t]he environmental studies of brake lining servicing operations outlined above together with the observation of mesothelial tumors in persons so employed affirms the necessity of instituting and maintaining recommended control measures." Id.

In 1986, the United States Environmental Protection Agency published a bulletin, "Guidance for Preventing Asbestos Disease Among Mechanics," Exhibit 6, that states:

Friction materials, such as brake linings and clutch facings,
often contain asbestos. Millions of asbestos fibers can be
released during brake and clutch servicing. Grinding and
beveling friction products can cause even higher exposures.
While lowering exposure lowers risk, there is no known level
of exposure to asbestos below which health effects do not occur 
. Mesothelioma is a type of fatal cancer of the lining of the
chest or abdominal cavity. It can be caused by very low
exposures to asbestos. This cancer has occurred among
brake mechanics, their wives, and their children.

Ex. 6 ( emph. added).

Dr. Lemen has published a peer-reviewed article on the subject. In this article, he, concludes: that "encapsulated asbestos containing brakes do release asbestos fibers…at concentrations capable of causing disease," Lemen, 2004, Ex. 1 at p. 234; "short asbestos fibers…pose a risk of disease," Lemen, 2004, Ex. 1 at p. 235; and, that "OSHA has stated that their current standard for asbestos [0.1 f/cc] will not eliminate the risk of asbestos-induced cancers." Lemen, 2004, Ex. 1 at p. 235. He notes that "[a] review of the published peer reviewed literature reveals at least 165 cases of mesothelioma in end-product users of friction products[, and that a]dditional government studies have reported other cases." Lemen, 2004, Ex. 1 at p. 234 ("[t]hese numbers cannot be attributed to ambient air exposure or to chance alone").

In a 1976 study, Rohl reported 2-15% chrysotile fiber and/or fibril forms in dust samples from car brake drums. Lemen, 2004, Ex. 1 at p. 231. He found concentration of 16 fibers/ml of air from blow out operations, and measurable concentrations 75 feet away 15 minutes later. Lemen, 2004, Ex. 1 at p. 231. Other studies have found intact chrysotile fibers released during brake repair in the range of 3.8 fibers/ml. See Lemen, 2004, Ex. 1 at p. 231-32. "[W]hile average concentrations can average much lower, excursion levels can reach much higher concentrations during certain operations of the brake maintenance and repair process exceeding the OSHA excursion limits and the 8 hour TWA for asbestos." Lemen, 2004, Ex. 1 at p. 232. Researchers have concluded that "excessive exposure to asbestos fibers occurs during brake servicing." Id.

"Fiber release studies of actual brake repair and replacement and the laboratory simulation studies both demonstrate the ability of encapsulated asbestos-containing brake products, to release respirable asbestos fibers at concentrations capable of causing asbestos related disease." Lemen, 2004, Ex. 1 at p. 232.

The EPA has reported that millions of asbestos fibers are released during brake and clutch servicing, and that this asbestos lingers in the garage. Lemen, 2004, Ex. 1 at p. 232. Studies found releases of asbestos fibers around and above the OSHA PEL (as of 2004). Lemen, 2004, Ex.1 at p. 232. One study found that when the worst control techniques were used, those engaged in brake and clutch repair operations for 7.25 hours per day would experience exposures in excess of the OSHA standard of 0.1 f/cc. Lemen, 2004, Ex. 1 at p. 232. As early as 1948, in a report by a GM employee, "[t]he National Safety Council reported that asbestos used in brakes was potentially harmful." Lemen, 2004, Ex. 1) at p. 233. Several studies report mesothelioma among auto mechanics, their wives and children. Id.

"Epidemiological studies have been equivocal." Lemen, 2004, Ex. 1 at p. 233. The plant where Teta et al. found three cases of mesothelioma, was the Raybestos brake manufacturing facility. Id. Another study found 17 mesothelioma deaths at a friction production plant (4.3% of the total). Id. "[Spairtas] reports 33 cases of mesothelioma in persons having stated as part of their occupational history brake repair work. One of the confounding factors preventing [Spairtas] from calculating a relative risk was that an overwhelming majority of those workers had also been exposed as insulators or shipbuilders." Lemen, 2004, Ex. 1 at p. 233. Teschke et al. found 6 cases of mesothelioma in vehicle mechanics among 51 cases, but did not conclude that mechanics showed an excess risk. Still, they acknowledge that most of these cases were caused by asbestos exposure and that "their findings were based on small numbers of cases and any judgments about causal associations would be speculative." Lemen, 2004, Ex. 1 at p. 234. Even a conservative interpretation of the Australian tumor registry study puts the rate of mesothelioma among automobile mechanics at 22.6 /million/year-"a rate substantially above the upper limit of the estimated background rate of 1-2 mesotheliomas per million person-years or around a 10-fold increase." Lemen, 2004, Ex. 1 at p. 234.

As early as the 1930's, there were published reports of asbestosis among workers in plants manufacturing brake linings. See Lanza, McConnell, Fehnel, (1935), "Effects of Inhalation of Asbestos Dust on the Lungs of Asbestos Workers," Publ. Health Rept. 50: 1-12, Exhibit 7 (high prevalence of asbestosis among workers, including plant manufacturing friction materials); Goerge, A.W. & Leonard, R.D., (1939), "An X-ray Study of the Lungs of Workman in the Asbestos Industry Covering a period of Ten Years," Radiology, 33: 196-209, Exhibit 8 (documents asbestosis in friction manufacturing workers since 1928); Stone, M.J., (1940), "Clinical Studies in Asbestosis," Amer. Rev. Tuberc., 41: 12-21, Exhibit 9 (asbestosis in 148 friction manufacturing workers); Stone, M.J., (1940), "Studies in Asbestosis," Dis . Chest, 6: 170-171, Exhibit 10 (asbestosis in 148 friction manufacturing workers). An industrial hygienist from General Motors published a report in the National Safety News, in 1948, concerning protective practices to be used when grinding friction materials. Exhibit 11. In 1963, a former General Motors industrial hygienist said of "[t]he sawing, filing, drilling and grinding of brake linings" that "[i]t is desirable in asbestos exposure to keep the dust count down to 5 million particles or less, per cubic foot of air." Patty, F.A., (1963), Industrial Hygiene and Toxicology (2 nd ed.), NY: Interscience, pp. 2243-44, Exhibit 12.

One study found unaltered chrysotile in garage air samples and concluded, "exposure of garage mechanics during brake lining maintenance and repair show that fiber concentrations frequently in excess of regulated limits are common." Rohl, A.N., Langer, M.S., Wolff, M.S. & Weisman, J. (1976), "Asbestos Exposure During Brake Lining Maintenance and Repair," Environ. Research, 72: 110-128, Exhibit 16. There are numerous published reports of mesothelioma in persons working with friction products. [1]


Chrysotile asbestos causes mesothelioma. It causes lung cancer, asbestosis and pleural disease. Scientists may dispute certain issues, such as the dustiness of a product, but these disputes are for a jury to decide.

The issue for the jury, not the judge, is whether asbestos exposure was a proximate cause of the illness and death of a plaintiff. Chrysotile asbestos fibers do not respect job classifications. Asbestos exposure increases the risk of mesothelioma, regardless of the person's job title. The issue is whether the injured person was exposed and how much and whether that exposure contributed to the disease or cancer.

As one court wrote: " As a matter of public policy, courts should not be hampered in the search for the truth by the rigid proposition that no expert, however qualified, can reliably opine on the causal link between a toxic substance and injury without epidemiological studies conducted according to strict guidelines."

1] These include, but are not limited to: Newhouse, et al., (1965), "Mesothelioma of Pleura and Peritoneum Following Exposure to Asbestos in the London Area," Brit. J. Indus. Med., 22: 261-269; Goodwin et al., (1968), "Asbestosis and Mesothelioma," JAMA, 204(11): 151 ; McDonald et al., (1970), "Epidemiology of Primary Malignant Mesothelial Tumors in Canada," Cancer, 914-918; Oels, et al. (Dec. 1971), "Diffuse Maliganant Mesothelioma of the Pleura: A Review of 37 Cases," Chest, 60(6): 564; Rubino, et al., (1972), "Epidemiology of Pleural Mesothelioma in North-Western Italy (Piedmont)," Brit. J. Indus. Med., 29: 436-442; Greenberg et al., (1974), "Mesothelioma Register 1967-68," Brit. J. Indus. Med., 31: 91-104; Vianna, et al., (May 1978), "Non-Occupational Exposure to Asbestos and Malignant Mesothelioma in Females," The Lancet, 1061-1063; Robinson, et al., (1979), "Mortality Patterns 1940-1975 Among Workers Employed in an Asbestos Textile Friction and Packing Products Manufacturing Facility," Dust and Disease, Pathotox Publishers, pp. 131-143; McDonald et al., (1980) "Malignant Mesothelioma in North America," Cancer, 46: 1650-1656; Langer, et al., (Nov. 1983), "Mesothelioma in a Brake Repair Worker," The Lancet; Kagan, et al., (1983), "Lymphoid and Plasma Cell Malignancies: Asbestos-Related Disorders of Long Latency," Amer. J. Clin. Path., 80(1): 14-15; Guillon, et al., (1984), "A Case of Association of Myeloproliferative Syndrome and Pleural Mesothelioma After an Asbestos Exposure," Archives Des Maladies Professionnelles De Medecine Du Travail Et De Securite Sociale, 45(2): 119; Castleman, (1984), Asbestos: Medicine and Legal Aspects, Harcourt Brace Jaovanovich; Woitowitz, et al., (1985), "Pleuramesothelioma After Asbestos Dust Exposure in Brake Repair Work in Automobile Repair Workshop: Case Observation," Praxis und Klinik der Pneumologie, 39(10): 362; Huncharek, et al., (1987), "Chrysotile Asbestos Exposure and Mesothelioma," Brit. J. Indus. Med., 44: 287-288; Newhouse, et al., (1989), "A Mortality Study of Workers Manufacturing Friction Materials: 1941-86," Brit. J. Indus. Med., 46: 176-179; Huncharek, et al., (1989), "Pleural Mesothelioma in a Lift Mechanic," Brit. J. Indus. Med., 46: 500-501; Jarvholm, et al., (1988), "Asbestos Associated Tumors in Car Mechanics," Brit. J. Indus. Med., 45: 645-646; Hansen, et al., (1989), "Mortality of Auto Mechanics," Scand. J. Work and Enviorn. Health, 15: 43-46.