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.
Factual error: There are no nuclear power plants or processing plants where sadistic 'decontamination crews' run down the halls in a panic as depicted in the movie. The high-pressure water, the torturous skin scrubbing, the screaming: it's all pure fiction, as was much of the movie.