On 3 November 1943, Osti's workforce was liquidated in its entirety in the course of Aktion Erntefest, the single largest German massacre of Jews in the entire war, with approximately 43,000 victims across District Lublin being shot in fake anti-tank trenches.[11] Subsequently, Horn complained in a report to Globocnik about the outcome of Aktion Erntefest; he stated that it had made Osti "completely valueless through the withdrawal [sic] of Jewish labor".[12] The company became officially defunct in March 1944.[6]