He saw that the figure of six million jewish people killed was a nonsens. He said also that Zyklon B was used for desinfection and crematories to incinerate the bodies. Today there are revisionists all over the world. This is a complete mistake. Especially if the gas used is Zyklon B or hydro-cyanic acid.
People mix up suicide by gas or accident by gas with execution by gas.
Among all the weapons gas is the most difficult to handle. If you wish to kill someone with gas, you do not want to kill yourself. Go and visit an american gas-chamber in a penitentiary, they execute only one man. In order to execute only one person you need extraordinary precautions. Air-tightness is a real problem.