Before 1993, any preexisting disability that was a hindrance to employment or reemployment could open the door to possible Second Injury Fund liability. The Second Injury Fund statute was amended in 1993 to limit permanent partial disability awards against the Second Injury Fund to those cases where both the preexisting disabilities and the disabilities from the work injury are more than de minimis. The provision defining what disabilities will trigger Second Injury Fund liability now states:
If any employee who has a preexisting permanent partial disability whether from compensable injury or otherwise, of such seriousness as to constitute a hindrance or obstacle to employment or to obtaining reemployment if the employee becomes unemployed, and the preexisting permanent partial disability, if a body as a whole injury, equals a minimum of fifty weeks of compensation or, if a major extremity injury only, equals a minimum of fifteen percent permanent partial disability, according to the medical standards that are used in determining such compensation, receives a subsequent compensable injury resulting in additional permanent partial disability so that the degree or percentage of disability, in an amount equal to a minimum of fifty weeks compensation, if a body as a whole injury or, if a major extremity injury only, equals a minimum of fifteen percent permanent partial disability, caused by the combined disabilities is substantially greater than that which would have resulted from the last injury, considered alone and of itself, and if the employee is entitled to receive compensation on the basis of the combined disabilities, the employer at the time of the last injury shall be liable only for the degree or percentage of disability which would have resulted from the last injury had there been no preexisting disability.
The thresholds found in the quoted provision serve to protect the Second Injury Fund from enhanced permanent partial disability claims of claimants with de minimis disabilities. And that is where the service of the thresholds ends. Section 287.220.1 goes on to say:
After the compensation liability of the employer for the last injury, considered alone, has been determined by an administrative law judge or
the commission, the degree or percentage of employee's disability that is attributable to all injuries or conditions existing at the time the last injury was sustained shall then be determined by that administrative law judge or by the commission and the degree or percentage of disability which existed prior to the last injury plus the disability resulting from the last injury, if any, considered alone, shall be deducted from the combined disability, and compensation for the balance, if any, shall be paid out of a special fund known as the second injury fund...(emphasis added).
Under the plain language of the statute, once it is determined that the thresholds are met, all disabilities that exist at the time of the work injury should be considered in the calculation of Second Injury Fund liability.