Firing someone for a work related injury is against the law. Or rather, firing someone for filing for workers compensation is against the law. That's called retribution. That's actually one of the few ways employers can get into trouble for work related injuries. Besides that WC mostly protects employers from being sued unless it's a contractor that is injured or causes the injury and they are not covered under the employer's workers compensation insurance. If you are covered under the employer's workers compensation and you suffer a permanent injury, you are screwed. Some doctors would rather not take workers compensation as payment because they always try to deny causation and try to get away with paying the absolute minimum they can for an injury. They do not exist for the good of the employee. Unless you are a veteran you are going to have a very hard time getting any sort of disability for tinnitus and hyperacusis regardless of the severity.