Since the formation of Prussian blue is not an unconditional outcome of exposure to cyanide, it is not a reliable indicator. Leuchter and Rudolf claim to have measured much more cyanide in the delousing chambers than in the homicidal gas chambers, but since they did not discriminate against an unreliable factor, Green maintains that instant bias is introduced into their experiments. Similarly, Rudolf acknowledges that Prussian blue does not always form upon exposure to cyanide and is thus not a reliable marker, yet continues to include the iron compounds in his analysis. Green describe this as "disingenuous". Since a building that contains Prussian blue staining would exhibit much higher levels of detectable cyanides than one without any, Green writes that Leuchter's and Rudolf's measurements reveal nothing more than what is already visible to the naked eye.