Watch Movies2Watch. Examines "hard metals disease," cobalt poisoning among workers in the tungsten carbide machine tool industry. Alpert focuses on workers suffering from this debilitating, incurable lung disease who were exposed to cobalt dust at three plants of the Valenite Metals Corporation. Establishing a close rapport with the workers as they tell their own stories of Valenite's negligence and subsequent cover-up, Alpert departs from standard television reportage in his powerful and unapologetic indictment of industry.