Continuity mistake: One of the last scenes of the movie, when Karen Silkwood is driving away from Dru they show her sitting in the car waving at him and the rearview mirror is clearly visible. Then she starts driving away, and the rearview mirror is gone. Then as she drives off, you can see the mirror has been replaced.
Factual error: Karen points out to Thelma that she should have given a nasal swab (to detect internal contamination) after being 'cooked', yet on both occasions when Karen is being scrubbed after being contaminated she has blisters all over her face - something which should be avoided when performing decontamination as this can allow contamination to enter the body.Andy Benham
Deliberate mistake: When they arrive in Washington D.C., they are seen in a 1976 Dodge Dart taxicab, but the movie supposedly took place in 1974. There are several scenes where many cars used in the movie are post-1974.
Karen Silkwood: You think I contaminated myself, you think I did that?
Mace Hurley: I think you'd do just about anything to shut down this plant.