Baby all i want for christmas how mariahs holiday staple all i want for christmas is you was just cemented in the history books. But first, the nightline 5. Good evening. Thanks for joining us. For years the waters in the town of parkersburg, West Virginia held a dangerous secret, one that slowly came to light after decades of persistent digging by one determined lawyer. Now his quest for justice explored in a new film thats drawing renewed focus on the everyday chemicals we may be exposed to. Nothing but the truth, so help you god. I do. Reporter actor and activist mark ruffalo is waging a new battle on capitol hill. These chemicals dont respect political boundaries. Reporter hes sounding the alarm about socalled forever chemicals, manmade substances that dont break down in the environment. They are found in every one of you. Reporter his new movie dark waters exposes how toxic they can be and how common. Du pont is knowingly poisoning 70,000 local residents for the last 40 years. Who