The killing mechanism consisted of a large internal-combustion engine pumping exhaust fumes into rooms through long pipes. Starting in February–March 1943 the bodies of the dead were exhumed and cremated in pits. Treblinka, the last camp to become operational, used knowledge learned by the SS previously. With two powerful engines, run by "SS-Scharführer" Erich Fuchs, and the gas chambers soon rebuilt of bricks and mortar, this death factory had killed between 800,000 and 1,200,000 people within 15 months, disposed of their bodies, and sorted their belongings for shipment to Germany.