In Williams v. Dept. of Corrections 224 Ga. App. 571 (481 S.E.2d 272) (1997), a prisoner sued the Department of Corrections for injuries sustained in a tractor accident. Williams' supervisor at the time of the accident was arguably an independent contractor. This Court held that, Even if the supervisor was determined to be an independent contractor of the state, the Department of Corrections could still be responsible for his negligence. Generally, an employer is not liable for the negligence of an independent contractor; however, exceptions exist when the work to be done involves a nondelegable duty which is dangerous to others no matter how carefully performed, when the work is a violation of a duty imposed by statute, or in other limited instances. Id. at 574-575.