Poniatowa was a small town 36 kilometres west of Lublin in eastern Poland. In the late 1930s, before the war, the Polish government had built a state telecommunications equipment factory there. After the German invasion the SS converted the factory complex into Stalag 359 in late 1941, a holding camp for Soviet prisoners of war captured during Operation Barbarossa. By the spring of 1942 around 20,000 of those Soviet POWs had died at Poniatowa from hunger, exposure, disease, and execution. In October 1942 the SS captain Amon Goth — who would shortly become the commandant of Plaszow — toured the site with redevelopment plans. The Reich needed slave labour for the textile factories of the SS Ostindustrie operation, and Walter Tobbens, a German clothing manufacturer who had been working Jewish slave labour in the Warsaw Ghetto, was being relocated as the ghetto was destroyed. Poniatowa became his new factory.

Most of the prisoners brought to Poniatowa in the winter and spring of 1942-43 came from the Warsaw Ghetto. They were the survivors of the Grossaktion of summer 1942, when 254,000 Warsaw Jews had been deported to Treblinka and gassed in two months. The people who reached Poniatowa were the ones the Germans had decided to work to death rather than kill immediately — skilled tailors, leather workers, mechanics. Around 15,000 Jews from Warsaw arrived first; smaller transports brought another 3,000 Jews from Slovakia and Austria, kept separately as the camp's so-called elite. The Germans also brought a few hundred Jewish women from the Bialystok Ghetto in the late summer of 1943. Conditions were brutal but not yet exterminationist; the factory needed the workers. The camp commandant Gottlieb Hering had previously commanded Belzec extermination camp until its closure in June 1943. The SS group that ran Erntefest was largely the same group that had run Operation Reinhard.

On 14 October 1943 the Sobibor extermination camp uprising broke out — about 300 Jewish prisoners overpowered their guards and escaped, a few dozen surviving the war. Two months earlier, on 2 August, the Treblinka uprising had done something similar. The SS leadership in Berlin concluded that the surviving Jewish slave labour population in the Lublin district was an active security risk. Heinrich Himmler personally ordered the liquidation of all Jewish prisoners in the Lublin district camps — Poniatowa, Trawniki, Majdanek, and the smaller satellite camps. The operation was code-named Aktion Erntefest. Detailed planning ran through October. SS reinforcements were brought in from Auschwitz and from killing units across the General Government. Anti-tank trenches were excavated by the prisoners themselves on the pretext of fortifying the camps against an anticipated Red Army advance. The trenches were the graves.

At Poniatowa the killing began on the morning of 3 November and ran into the afternoon of 4 November. In one of the barracks, on the first day, a group of Jewish prisoners refused to come out and barricaded themselves inside. The SS surrounded the building and set it on fire. The smoke drew a fire brigade from the village of Poniatowa, which had not been informed. The firemen reached the camp gate and were turned back by SS men screaming at them to leave. As they left, they saw a man running from the burning barracks bludgeoned with rifle butts and thrown back into the flames. The ground around the barracks, witnesses told postwar investigators, was covered with the bodies of women. The mass killings continued the next morning. Around 14,000 people died at Poniatowa in two days. At the broader Aktion Erntefest, the total exceeded 42,000 — the largest single-operation killing of Jews in the entire Second World War. The camp was closed. Hering was reassigned to Trieste with other Operation Reinhard staff. He died of natural causes in October 1945. The first monument to the victims was placed at the site in 1958 by the Polish authorities. A specific memorial to the Jewish dead, naming the 14,000 victims of the Erntefest in Poniatowa, was unveiled on 4 November 2008, sixty-five years to the day after the killings.