I worked at DOL for 24 years. What most workers do not realize is that many states are "work at will". That means that theoretically the employment contract or agreement can be severed by either party with NO REASON GIVEN. Even though it might be technically illegal to let someone go who is injured there is really no policing authority to stop wrongful termination. The only remedy seems to be a "civil action" where you find your own lawyer. With courts now dominated by pro business RW judges civil action success is doubtful
Department of Labor has been largely neutralized by budget cuts and infiltration of Bush appointees and employee salting by Bush during his 8 years in office. In fact Mitt Romney will likely push to shut down the Labor Department if he wins election. And the GOP will likely abolish the Fair Labor And Standards Act which set up labor standards in this country. They are serious about ending all labor laws that protect workers.
Workman's Compensation is one agency on the way to be "pofitized". In Colorado Workman's Compensation was partially privatized years ago when it was a state agency. Now business elements in Colorado are trying to completely privatize it. That means its operation would be contracted out to a corporation. Essentially what that means is that corporate doctors would be assessing injuries to workers.
It is common practice for American business to dump injured or older workers with health problems. Anymore I am not sure that it is illegal because "work at will" favors the employer. The GOP and business manta is that "if you don't like your working conditions where you are, you can quit and go to another employer. No one is stopping you."