That simply isn't true. I visited just four of the former camps in Northern Germany in June 2012, Bergen-Belsen, Neuengamme, Ravensbrueck and Sachsenhausen, and with the exception of Belsen, all of them are still claimed to have operated a homicidal gas chamber. I've already documented with photographic evidence what the museums at Ravensbrueck and Sachsenhausen presently claim about gas chambers at those camps, but until now I've never published photos of the Neuengamme ad hoc gas chamber.
Detention bunker (camp prison)
The detention building (called simply 'the bunker' in camp jargon) was equipped with five solitary confinement cells for the enforcement of particular camp punishments, i.e. light deprivation. From 1942 onwards, increasing numbers of prisoners were hanged in the tract's corridor. This was compounded by the Gestapo, which brought hundreds of people here to be executed. On two occasions in autumn 1943 the SS killed Soviet prisoners of war using Cyclon B poison gas: 197 POWs in September and 251 in late November. The victims of the second wave of murders were mostly war-wounded. Here, in the nights of 21-24 April 1945, shortly before the camp was evacuated, the SS killed 71 men and women from the Fuhlsbüttel police prison in Hamburg.
The building continued to serve as detention cells after 1945. It was torn down in 1950.
In the early days of the concentration camp, bodies were still cremated at the crematorium in Ohlsdorf cemetery. In autumn 1942, when the number of victims had increased, the SS had a "provisional cremation facility" erected near the sewage plant.
As the number of fatalities continued to grow, the SS started the construction of a new crematorium in autumn 1944. By the end of the same year, the first two furnaces were finished and put into operation.
The gold teeth of the victims were removed from their jaws before their bodies were cremated. The SS had their ashes buried near the crematorium and on the grounds of the camp nursery. The crematorium was demolished in late 1946/early 1947.
After a campaign by Neuengamme survivors who has joined together in the "Amicale Internationale", the site of the new crematorium was marked by a commemorative plaque in 1970.