Keneally actually does make one error here. The deniers are factual in their claim that Zyklon-B was primarily used as a delousing agent. It was Auschwitz commandant Rudolf Höss who, noting the frequent problems with building sufficient lethal concentration of exhaust gas at the Reinhard camps, decided that Zyklon-B would work better - and so it proved.
All evidence at Lublin points to the use of bottled carbon monoxide and engine exhaust as the killing agent, and no evidence has been produced to show that the Zyklon-B at the Reinhard camps was used for anything other than delousing.
Confusion by non-historians such as Keneally are cited by the deniers
as deliberate lies and myths, and the contradictions between such
statements and those of serious historians, as well as early statements
compared with later scholarship, are cited as evidence of a
conspiratorial hoax that is just about to fall apart at any moment.