Workers who suffer successive work injuries also tend to have a tougher time securing benefits, particularly if the injuries occurred under the watch of different employers.
In these cases, benefits must be apportioned based on what percentage of worker's ailments were caused by which injury. This can result in a complicated process that will involve extensive review of medical records, numerous independent exams and testimony from expert witnesses.
The case of Warren Props. v. Stewart is illustrative, having ping-ponged through various courts trying to sort out the appropriate course of action for successive injuries at separate employers. Most recently, the case was before the Iowa Supreme Court. That court held an employer who is liable to compensate a worker for a work-related injury does not have to pay for pre-existing disability that arose from employment with a different firm, or from causes unrelated to employment when the worker's earning capacity wasn't re-evaluated in the competitive job market prior to the successive injury and after.