Worker's compensation covers any injury or illness that is related to the workplace. This includes physical injuries, psychological illnesses, and mental impairments caused by chronic stress from a hazardous job environment. Worker's compensation can also cover medical expenses for pre-existing conditions if the condition was aggravated or worsened due to work-related activities. It is important to note that worker's compensation is not limited to accidents and can include any type of injury or illness sustained on the job.