If you have a workplace injury or occupational disease, your only remedy is likely through the workers' compensation system. You cannot file a direct lawsuit against your employer in most cases. (There are exceptions, such as discrimination related to your workers' compensation claim, discussed below.) But for recovery of medical expenses and other costs related to your work-related injury or occupational disease, you cannot sue your employer.
In every state, workers' compensation is a benefit system designed to be "no fault," meaning it is irrelevant whether your employer's negligence (carelessness) contributed to your work-related injury or occupational disease. What matters is that you were involved in a workplace injury or suffered an occupational disease in the course of your employment.
Additionally, in most circumstances, an employee's own negligence will not prevent that employee from getting workers' compensation benefits. (If you have questions about whether your behavior leading to your work-related injury might preclude your eligibility for a workers' compensation claim, talk to a workers' compensation attorney in your area.)
The no-fault system was designed to protect both workers and employers. It was designed to protect employers from expensive and time-consuming lawsuits, and to protect employees by ensuring medical care and time off benefits.
Recovery is the amount of money or reimbursement for medical treatment that you will receive for your injury. Because of the no-fault system, your recovery is limited. Since you cannot file a lawsuit, you cannot get punitive damages (money awarded to punish your employer). However, workers' compensation benefits can be substantial, depending on the state you live in. Washington, for example, is very generous to injured workers. Texas and California, on the other hand, are not as generous with workers' compensation benefits.
Workers' compensation benefits include lost wages, medical bill reimbursement, and disability benefits. Workers' compensation injury benefits can also include death benefits if a worker is killed on the job.
You are only eligible to file a workers' compensation claim if you are an employee covered by workers' compensation in your state. Independent contractors, volunteers, and others are not covered employees. If you aren't covered by workers' comp, and the negligence of the person or company you were working for contributed to your injury, you may file a regular personal injury claim lawsuit, since you cannot file a workers' compensation claim.
If you are a covered employee, then in most states you can only file a lawsuit against your employer in very specific circumstances. One of these circumstances is if your employer intentionally acted to harm you, specifically. In most jurisdictions, this means that your employer actually must have done something on purpose to harm you. But usually you must file a workers' comp claim. Even if your employer was grossly negligent, for example, if they did not repair a broken ladder or if they left a dangerous piece of machinery where you could fall onto it, this is not enough to entitle you to file a private lawsuit.
To be able to prevail in a private lawsuit for intentional harm, you must be able to prove that your employer acted with intent to harm, such as physically punching you or some other such intentionally harmful act. You may have a claim against both your employer (the company) and the individual(s) responsible for harming you.
In some cases, you may also be able to sue a third party other than your employer who is partially responsible for your injury. For example, if a defective product you used at work injured you, you might be able to sue the manufacturer of that product, in addition to filing a workers' compensation claim. This may entitle you to greater recovery, including punitive damages.
Another frequent third party lawsuit involves motor vehicle accidents. If you were driving for work and were involved in an accident, you will have a workers' compensation claim and you may have a third party claim against the driver(s) that hit you.
For more information, see Nolo's article on When You Can Sue Outside of Workers' Compensation.
Third party lawsuits can be especially complicated as a result of co-employment rules built into workers' compensation statutes. You should consult a lawyer experienced in worker's compensation and job-related injuries in order to determine the best course of action for filing suit against employers or third parties.