Each year, six thousand Americans lose their lives on the job. Tens of thousands more are seriously injured or exposed to deadly poisons and carcinogens in the workplace. Yet if one of those workers dies on the job due to a company's willful disregard for federal safety regulations, the maximum penalty his employer faces is just six months in prison. Are America's workplace safety laws tough enough? And are companies being held responsible for protecting the safety of their employees? FRONTLINE investigates workplace safety in one of America's most dangerous industries.