During a visit to Minsk in August 1941, Himmler witnessed an Einsatzgruppen mass execution first-hand and concluded that shooting Jews was too stressful for his men.[119] By November he made arrangements for any SS men suffering ill health from having participated in executions to be provided with rest and mental health care.[120] He also decided a transition should be made to gassing the victims, especially the women and children, and ordered the recruitment of expendable native auxiliaries who could assist with the murders.[120][121] Gas vans, which had been used previously to kill mental patients, began to see service by all four main Einsatzgruppen from 1942.[122] However, the gas vans were not popular with the Einsatzkommandos, because removing the dead bodies from the van and burying them was a horrible ordeal.