Most states, including DC, VA, and MD, have provisions that your employer cannot fire you in response to protected behavior such as filing of a workers' compensation claim (called retaliation). But that is rarely the issue.
However, your employer can fire you while you have an open workers' compensation claim for any legal reason if you are an at will employee (union workers may have protections through their union). Sometimes employers say they need to fill your position, and with a serious injury you may not be able to return to your job because you can no longer physically perform the work. Your doctor may have restricted you from lifting, bending, standing, reaching overhead, and other work activities.
Just because your company terminates your employment doesn't mean your workers comp case is over. In fact, it has very little to do with workers comp. The workers comp insurance company will still have to pay your workers comp benefits and medical treatment while you cannot work because of your injuries.
The effect of termination on your workers comp case is often a complicated issue and can affect settlement and other issues - so if you're in that situation, give us a call to see if we can help you take care of your case and your future (202) 393 - 3320.