GAINESVILLE, Ga, (AP) — A liquid nitrogen leak at a northeast Georgia poultry plant has killed six people and sent 11 others to the hospital. At least three of those injured at the Foundation Foods Group plant in Gainesville were reported in critical condition Thursday. Poultry plants rely on refrigeration systems that can include liquid nitrogen. Authorities are investigating the cause of the leak. Northeast Georgia Health System spokesman Sean Couch says eleven other injured patients were treated for respiratory symptoms at the hospital. At least four firefighters were injured. Gainesville is the center of Georgia’s huge poultry industry and has thousands of employees working in multiple processing plants.