Many of the prisoners worked in the midst of the production process. They stood next to the evaporator from which a mixture of anthracite, sulfur, and carbon black was extracted. Although it was 60 to 79 degrees [Fahrenheit] in the production halls, the prisoners had to wear protective clothing up to their neck in order to protect their body against the carbon black. Waste heated to 300 degrees flowed from the evaporator. The prisoners had to carry this in buckets to a basin on the factory site.  The extracted carbon black was channeled out of the factory through a system of pipes, then weighed outside the factory and packaged in paper bags.