If I lost a limb on the job, could they be replaced?

Excellent options. Artificial legs, arms and hands with highly functional and visibly pleasing materials is very real today. Actual transplantation of the hand with tissue from a human being (who has died) has the advantage of also providing sensation, which no artificial replacement part yet does. But the need to take medication to prevent rejection, with high cost + important side effects is a big issue too.
Yes. Hand and arm transplants have been done successfully from deceased donors. However, they are only done at a few centers in the US, are a major undertaking, and require and intense evaluation process with the transplant team, psychologists, social workers, and rehabilitation staff.