Workers can sustain injuries that occur over a long period of time while working for several employers. Prime examples include repetitive stress injuries like carpal tunnel syndrome or epicondylitis. Noise induced hearing loss is another good example.
Generally, an injured worker has to be able to prove that exposure to work activities or conditions caused a need for treatment, disability, or in some cases, the actual medical condition. However, this can become difficult when the problem has occurred gradually over several years. For example, a plywood millworker may work in the same plywood mill over the course of a couple of decades. During that time, the plywood mill may change ownership two or three times. If that worker suffers a hearing loss, it can be difficult to show exactly when the hearing loss began, in which employer caused the most significant portion of the hearing loss.
To deal with this issue, the Oregon Workers' Compensation statute employs the "last injurious exposure rule." This rule provides a "presumption" that the conditions at work for the last employer caused the compensable on-the-job injury. The key here is that the on-the-job injury or condition is "compensable." This means that the injured worker first must establish that the condition, whether it be a hearing loss or repetitive stress injury, is due in major part to exposure to conditions at work.
Once the worker gets over this hurdle, then the several employers may have a fight between themselves as to which employer is responsible for the claim. If the last employer is able to prove that it is not possible that the compensable condition could have occurred under their watch, then responsibility for the claim could be pushed back to a previous employer.
A good example is the plywood mill and hearing loss. A plywood mill in the 1970s may have not employed occupational safety measures to prevent occupational hearing loss. However, a new owner of the plywood mill may have installed noise reduction technology, and may have taken much better care of its workers to prevent hearing loss. If that subsequent employer can prove that it would be impossible for a worker to sustain hearing loss during its ownership of the mill, then these last employer may successfully evade responsibility for the hearing loss claim.
The good news is that the injured worker, once he proves that the condition he suffered his work related, does not have to worry about which employer or insurance company is responsible for the claim.
In this case, the Board found that a prior employer was responsible for a shoulder condition. The medical opinions, which are always centrally important in cases like this, stated that the last employment "may" have caused worsening of the shoulder problem, but more likely than not, the problem arose during the prior employment. This opinion was not sufficient enough to shift responsibility to the last employer.this is because medical opinions in workers' compensation must be expressed in terms of "probability." In other words, the doctor has to state that the work activity was more than 50% likely the cause of the resulting injury or need for treatment.
Definitions are everything in Oregon Workers' Compensation. If your interested in the definition of a "compensable injury," check out this article.