Documentary programme Report Mainz, which was broadcast on ARD state television on Tuesday evening, said the German Democratic Republic (GDR) sold the blood of prisoners through a Swiss middleman to the Red Cross branch of the state of Bavaria.
The programme on forced labour carried out by GDR prisoners also said West German companies in a wide range of industries were taking advantage of the low-to-non-existent wages. Swedish home furnishing giant Ikea apologized after its archives threw up similar revelations.
It named Aldi and Volkswagen as two of the larger users of forced labour – even though their involvement may have been indirect and even unknowing.
A report called "Prison products for the class enemy", written by historian Tobias Wunschik from the Stasi archive collection of East Germany's secret service files, lays bare the trade between East and West Germany between 1970 and 1989.
Head of the archive Roland Jahn told the programme makers: "The research project showed Ikea was just the tip of the iceberg. It is has become clear from the study that many more companies than were until now known, were involved in this trade of goods which were produced by prisoners in the GDR."
Wunschik said: "There were very many western companies which were heavily involved in GDR trade. The GDR was, from a company point of view, a low-wage economy. And also geographically nearby, and without, for example, language problems.
"Many hundreds of western firms were active in East-West trade, many sourced goods from the GDR, and prisoner labour was involved in very many of these goods. The fragmented data that we have allows us to estimate that each year at least 200 million Deutschmark turnover was achieved with goods that were only produced with prisoner labour."
The files showed that Germany's leading discount supermarket empire Aldi bought goods from an East German company which used prisoner labour. The GDR state-owned firm VEB Esda Thalheim produced tights with the forced labour of women prisoners held in the notorious Hoheneck prison.
Both Aldi Nord and Süd confirmed to the programme makers their involvement with Esda Thalheim. A statement from Aldi Nord said: "We regret and condemn in the harshest terms the seemingly widespread practice of using the forced labour of political and non-political prisoners to produce goods." A statement from Aldi Süd was similar, the programme-makers said.
The first evidence also emerged that Volkswagen was also involved. The car-making giant confirmed to Report Mainz that it used to get a range of parts such as lamps, wheel nuts and fog lights from the East German state-owned form VEB Kombinat Fahrzeugelektrik Ruhla. Old files show that prisoners were used as labour there.
Volkswagen said in a statement: "Volkswagen did not and does not know in which area of operation of the Kombinat, which products were produced – nor is there any knowledge of the possible use of prisoners in GDR companies which delivered to Volkswagen. Volkswagen neither caused the use of prisoners in GDR companies, nor knowingly approved, let alone profited from it."
Even though trade with the west was generally dealt with by specific East German foreign commerce bodies – which would have tried to keep the use of prisoner labour secret – Wunschik said the western firms had a responsibility.
"One did not go into the companies and take a look at the production line. That would have been possible. The GDR was so keen for hard currency that particularly big traders would have been able to exert a certain degree of power if one had really been interested."
And Jahn added: "Whoever dealt with a dictatorship could never be certain about under which conditions products were made."
He called for the companies to open their archives and to provide financial support for further research.
"The West German firms should contribute more to research, in order that compensation can be made," he said.