The scene where Karen sets off the radiation alarms actually happened. Her level of contamination was forty times the safe limit.
The movie is based on a true story. The picture was released nine years after the events depicted in the film, in 1974.
Reportedly, the production of this film set a legal precedent in the U.S. Supreme Court regarding the protection of confidential sources for filmmakers under the First Amendment, as is the case for media reporters (See: Stephen F. Rohde, 5 Pepp. L. Rev. 351 (1977-1978), "Real to Reel: The Hirsch Case and First Amendment Protection for Film-makers' Confidential Sources of Information").
Movie posters for the film featured a preamble that read: "On November 13, 1974, Karen Silkwood, an employee of a nuclear facility, left to meet with a reporter from the New York Times. She never got there".
Despite Karen's fame after her death for her activism, her three children never fully got over her leaving them with their father and his girlfriend after their parents split up. In NewsOK, the children were quoted saying, "To tell the truth, we were kind of glad that publicity died down after a while. It made it easier to move on. I really, really appreciate what she did for the world, I can't appreciate what she did for me, my brother, and my sister." People magazine reports that Michael Meadows' clearest memory of his mother is a swat on the buttocks for using a soft drink rather than milk in a bowl of cereal. "It's sad that you remember a BAD thing," he said.