Mesothelioma Claims in Workers Compensation:
Enhanced Benefits, Enhanced Risk

By Justin Reinhardt, VBM Attorney

Article written June 14, 2024


In 2014, The Workers’ Compensation Law was amended in Missouri to add enhanced benefits for employees diagnosed with “occupational diseases due to toxic exposure” including mesothelioma, asbestosis, berylliosis, coal worker's pneumoconiosis, bronchiolitis obliterans, silicosis, silico-tuberculosis, manganism, acute myelogenous leukemia, and myelodysplastic syndrome. RSMo § 287.020.11; RSMo § 287.200.4.

For mesothelioma, an “additional amount of three hundred percent of the state's average weekly wage for two hundred twelve weeks shall be paid by the employer…” RSMo § 287.200.4(3)(a)(emphasis added).

These enhanced benefits equate to enhanced risk for Missouri employers. Understanding the law and science of mesothelioma is key to navigating these challenging claims.

What is Mesothelioma?

Mesothelioma is cancer of the thin tissue (mesothelium) that lines the lung, chest wall, and abdomen. See Pavlisko, E.N., Sporn, T.A. (2014). Mesothelioma. In: Oury, T., Sporn, T., Roggli, V. (eds) Pathology of Asbestos-Associated Diseases. Springer, Berlin, Heidelberg. The most common type of mesothelioma is pleural mesothelioma, cancer of the lining of the lung, followed by peritoneal mesothelioma, cancer of the lining of the abdomen. See id. Mesothelioma can be caused by exposure to asbestos, erionite, radiation, and simian virus 40. See id.

As it relates to The Workers’ Compensation Law and “occupational disease,” the historic use of asbestos in many products found in the workplace, particularly in the construction and industrial settings in the ‘60s, ‘70s, and ‘80s, is the primary concern. Determining the extent to which an exposure to asbestos is a medical/legal cause of an employee’s mesothelioma is a complicated and nuanced analysis.

The Law on Causation: Prevailing Factor

Causation in occupational disease cases in defined under The Workers’ Compensation Law as follows:

An injury or death by occupational disease is compensable only if the occupational exposure was the prevailing factor in causing both the resulting medical condition and disability. The “prevailing factor” is defined to be the primary factor, in relation to any other factor, causing both the resulting medical condition and disability.

RSMo § 287.067; see also Hayden v. Cut-Zaven, Ltd., 614 S.W.3d 44, 55 (Mo.App. E.D. 2020).

In addition, an injured employee “must prove (1) his or her ‘exposure to the disease ... was greater than or different from that which affects the public generally’ and (2) ‘there was a recognizable link between the disease and some distinctive feature of the employee's job which is common to all jobs of that sort.’” Hayden, 614 S.W.3d at 55 (internal citations omitted).

Determining whether an asbestos exposure in the workplace was a “prevailing factor” touches on many different considerations including the type of asbestos fiber at issue and the nature of the asbestos containing products at issue.

Prevailing Factor Considerations: Fiber Type and Products at Issue

It is important to initially note that asbestos is a generic term for a group of naturally occurring minerals which is divided into two very distinct mineralogic groups, amphiboles (including crocidolite, amosite, tremolite, anthophyllite, and actinolite) and serpentine. See In re Garlock Sealing Tech., LLC, 504 BR 71, 75 [Bankr WDNC 2014]. Of the serpentine group, chrysotile is the sole variety. Id. There is a stark difference in the chemical make-up of amphibole and chrysotile asbestos fibers and their ability to cause disease. Id.

Of the amphiboles, only crocidolite and amosite gained widespread commercial use, but on a relatively limited basis. See Roggli, V.L., Coin, P. (2004). Mineralogy of Asbestos. In: Roggli, V.L., Sporn, T.A., Oury, T.D. (eds) Pathology of Asbestos-Associated Diseases. Springer, New York, NY. It is chrysotile that accounted for most of the commercial use of asbestos in the United States. See id.

Identifying the type of asbestos in the product(s) at issue is key for a causation/prevailing factor analysis because, while chrysotile was used the most, amosite and crocidolite carry a far greater risk of causing mesothelioma. In fact, well recongized experts in asbestos and disease causation note, “the evidence that pure chrysotile, uncontaminated by amphibole asbestos, results in the development of mesothelioma in humans is limited and low-level exposures are unlikely to increase such risk.” See Pavlisko, E.N., Sporn, T.A. (2014). Mesothelioma. In: Oury, T., Sporn, T., Roggli, V. (eds) Pathology of Asbestos-Associated Diseases. Springer, Berlin, Heidelberg.

In addition to determining the fiber type at issue, it is important to understand the asbestos containing products at issue. “Sola dosis facit venenum,” the dose makes the poison. Not all asbestos containing products have the same ability to release asbestos fibers when manipulated and thus do not have the same propensity to cause disease. See Gideon v. Johns-Manville Sales Corp., 761 F.2d 1129, 1145 (5th Cir. 1985) ("[A]ll asbestos-containing products cannot be lumped together in determining their dangerousness.  Proof that asbestos insulation products are dangerous or defective does not satisfy the burden of proving that products used for other purposes, such as asbestos textiles with encapsulated asbestos fibers, are dangerous.") (emphasis in original).

In other words, certain products can create much higher potential exposure, higher potential doses of asbestos, than others, particularly friable products like thermal insulation and spray fireproofing. “Friable means that the material can be crumbled with hand pressure and is therefore likely to emit fibers.”29 CFR 1926.1101, Appendix H, 1994.

This is distinguished from non-friable products, like floor tiles and gaskets, in which the asbestos fibers were encapsulated in the product during the manufacturing process which significantly reduces or eliminates the potential for release of asbestos fibers when the products are later manipulated.

Asbestos was incorporated into some 3000 different products throughout its use. Determining the asbestos fiber type and the friability/encapsulation/potential fiber release for the product(s) at issue is key to determining if any given workplace exposure was a prevailing factor in the development of mesothelioma.

Last Employer Liable

As a final important consideration, under The Workers’ Compensation Law, “The employer liable for the compensation… [is] the employer in whose employment the employee was last exposed to the hazard of the occupational disease prior to evidence of disability, regardless of the length of time of such last exposure…” RSMo § 287.063. Thus, a detailed work history of the employee through a thorough deposition ensures that the correct employer/entity is in the case.


Given the complexities of mesothelioma causation and the enhanced risk at issue, special care is necessary in the handling of such claims. Detailed deposition taking and factual development, retention of the correct and highly qualified experts, and skilled cross examination of claimant’s experts ensure the increased risk is properly managed.

VBM and Partner, Justin Reinhardt, has a wealth of experience defending asbestos/mesothelioma cases, [Learn more about Justin]. Please contact us for any additional information. Thank you.   |   (573) 777-4488  |