There is little or nothing you can do after the fact. If the injury was do to something you did wrong--for example, did not train him to do the thing you asked him to do; provided inadequate safety gear, or no safety gear; the tools you gave him were the wrong ones for the job or in bad repair; you personally or another employee accidentally cut him; etc.--then you could be liable. On the other hand, if you and the company did nothing wrong, you would not be liable for his injury, so if he cut himself do to his own carelessness or the actions of some unrelated third party, that should not impose liability on you.Before the fact, you can protect yourself by NOT having a illegal immigrant working for you, and by paying Worker's Compensation assessments and having adequate liability insurance, to make sure you are covered. Of course, Worker's Comp will probably not cover an illegal immigrant, since you can't make contributions for him to the system (he's not eligible to work in the U.S.) and your liability insurance probably has one or another exception to coverage for this situation.