September 3, 1941

Auschwitz concentration camp

First mass killing with Zyklon B begins at Auschwitz

When an SS man opened the basement the next morning, some prisoners were still alive. The perpetrators closed it again and added more poison.

Probably 3 September 1941: Block 11

Probably on 3 September 1941 — the Auschwitz-Birkenau State Museum's own qualifier, since surviving accounts differ over the precise chronology — camp personnel confined approximately 860 people after evening roll call in 28 basement cells of Block 11 at Auschwitz I: about 600 selected Soviet prisoners of war, about 250 sick Polish prisoners from the camp hospital, and ten men from the penal company, jailed after another prisoner's escape.

On the orders of camp director Karl Fritzsch — deputizing while commandant Rudolf Höss was away — SS personnel poured Zyklon B pellets through the cellar windows and covered the windows with earth.

A killing that continued into 4–5 September

The event was not completed in a day. On the morning of 4 September, SS report leader Gerhard Palitzsch checked the basement and found some victims still alive; a second dose of gas was introduced. All were dead by the night of 4–5 September.

Nor was this the very first homicidal use of Zyklon B at Auschwitz: smaller experiments on Soviet POWs probably occurred in the last days of August. September 3 marks the first mass-scale killing — in Block 11's basement, not in the old crematorium.

What followed the experiment

The crematorium furnaces could not process the bodies promptly; some remained in the morgue for days, and others were probably buried.

Afterward, the SS adapted the morgue of Crematorium I as a gas chamber, with the provisional Birkenau installations following in 1942.

Sources

Researched 23 Aug 2026 5 sources 3 audit passes Traditional date

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Traditional date. Conventionally dated here; the research places it at ~1941-09-03.

What the sources leave uncertain

The Auschwitz-Birkenau State Museum says the mass killing 'probably' began on September 3; surviving prisoner accounts and postwar recollections differ over the precise chronology.
September 3 was not the very first homicidal use of Zyklon B at Auschwitz. Smaller experiments involving Soviet POWs probably occurred during the last days of August.
The killing extended beyond a single day: survivors of the first dose were found on September 4, and all victims were dead by the night of September 4–5.