Glossary Check
In Missouri, workers’ compensation claims must have an “occupational disease” with a certain type of “prevailing factor” to be compensable. What do those terms mean? As Simply Research subscribers know, Show Me State law defines them as follows.
Occupational Disease
“Occupational disease” is defined to mean, unless a different meaning is clearly indicated by the context, an identifiable disease arising with or without human fault out of and in the course of the employment. Ordinary diseases of life to which the general public is exposed outside of the employment shall not be compensable, except where the diseases follow as an incident of an occupational disease as defined in this section. The disease need not to have been foreseen or expected but after its contraction it must appear to have had its origin in a risk connected with the employment and to have flowed from that source as a rational consequence.
Prevailing Factor
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. Ordinary, gradual deterioration, or progressive degeneration of the body caused by aging or by the normal activities of day-to-day living shall not be compensable.
Repetitive Motion Injuries
An injury due to repetitive motion is recognized as an occupational disease. An occupational disease due to repetitive motion 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. Ordinary, gradual deterioration, or progressive degeneration of the body caused by aging or by the normal activities of day-to-day living shall not be compensable.
With regard to occupational disease due to repetitive motion, if the exposure to the repetitive motion which is found to be the cause of the injury is for a period of less than three months and the evidence demonstrates that the exposure to the repetitive motion with the immediate prior employer was the prevailing factor in causing the injury, the prior employer shall be liable for such occupational disease.
Case Examples
Miller v. Missouri Highway and Transportation Commission, 287 S.W. 3d 671 (Mo. 2009). An injury will not be deemed to arise out of employment if it merely happened to occur while working but work was not a prevailing factor and the risk involved — in this case, walking — was one to which the worker would have been exposed equally in normal non-employment life. The injury did not occur because the worker fell due to some condition of his employment. He did not allege that his injuries were worsened due to some condition of his employment or due to being in an unsafe location due to his employment. He was walking on an even road surface when his knee happened to pop. Nothing about work caused it to do so. The injury arose during the course of employment but did not arise out of employment.
Malam v. Missouri Department of Corrections, 492 S.W. 926 (Mo. 2016). After a corrections officer executed a “takedown” on an inmate, he became short of breath and began spitting up blood before being taken by ambulance to the hospital where he experienced a “hypertensive crisis” and was unconscious for a week Although the officer had an underlying hypertensive cardiomyopathy identified as far back as 2005, the prevailing factors precipitating the specific event were the unexpected emotional and physical stresses associated with restraining the inmate.
