There are many people who struggle constantly with drugs or alcohol. Of course, people who have these addictions may also get sick or hurt, just like everyone else. When this happens, they may not be able to return to work because of their medical condition.
People make mistakes all the time. Even responsible and careful Philadelphia drivers will, from time to time, blow a red light or totally miss the fact that the traffic in front of them has come to a stop. On other occasions, a worker in one of the area's many factories or construction sites may just forget about taking an important safety step.
There was recent good news for the famous, or rather infamous, disability trust fund. For those who are not aware, the trust fund is a government asset which can be and often is used to help pay disability benefits when the volume of claims do not keep pace with revenues from payroll taxes.