Editing Aktion T4 (section)

== Technology and personnel transfer to death camps ==
{{see also|Category:Aktion T4 personnel|T4-Gutachter}}
After the official end of the euthanasia programme in 1941, most of the personnel and high-ranking officials, as well as gassing technology and the techniques used to deceive victims, were transferred under the jurisdiction of the national medical division of the Reich Interior Ministry. Further gassing experiments with the use of [[gas van|mobile gas chambers]] ({{lang|de|Einsatzwagen}}) were conducted at [[Soldau concentration camp]] by Herbert Lange following [[Operation Barbarossa]]. Lange was appointed commander of the [[Chełmno extermination camp]] in December 1941. He was given three gas vans by the [[Reich Security Main Office]] (RSHA), converted by the Gaubschat GmbH in Berlin{{sfn|Beer|2015|pp=403–417}} and before February 1942, killed 3,830 [[Polish Jews]] and around 4,000 [[Romani people|Romani]], under the guise of "resettlement".{{sfn|Ringelblum|2013|p=20}} After the [[Wannsee conference]], implementation of gassing technology was accelerated by Heydrich. Beginning in the spring of 1942, three killing factories were built secretly in east-central Poland. The ''SS'' officers responsible for the earlier {{lang|de|Aktion&nbsp;T4}}, including Wirth, Stangl and [[Irmfried Eberl]], had important roles in the implementation of the "Final Solution" for the next two years.{{sfn|Sereny|1983|p=54}}{{efn|Role of T4 "Inspector" Christian Wirth in the Holocaust.{{sfn|Sereny|1983|p=54}}}} The first killing centre, equipped with stationary gas chambers, modelled on technology developed under {{lang|de|Aktion&nbsp;T4}}, was established at [[Bełżec]] in the [[General Government]] territory of occupied Poland; the decision preceded the Wannsee Conference of January 1942 by three months.{{sfn|Joniec|2016|pp=1–39}}