Zyklon B
In 1943 Klehr became head of the disinfection squad ("Desinfektionskommando"). As a handler of Zyklon B his tasks included not only delousing living quarters and clothes, but direct involvement in the mass gassing of prisoners. He was one of those responsible for inserting the gas. He was present during selections where those incapable of working were sent to the gas chambers, and drew up a schedule as to who under him was to insert the Zyklon B.