The cement industry is key to the war effort: After the start of the war, all cement plants continue operating at full capacity to provide the necessary fortifications and equipment. The military draft, however, soon results in a shortage of labour, so that production targets cannot be met. Increasing numbers of women, as well as prisoners of war, and forced labourers from occupied Europe, come to work at the plants.

The plants make it through the war more or less undamaged. Depending on the zone they are in, many are able to resume operations after a short period of shutdown. Nonetheless, worn-out machines and energy shortages stand in the way of a rapid recovery in production. Many of the company’s former employees have fallen in the war, are prisoners, or are prohibited from working as a result of de-Nazification – a lack of qualified personnel is the result. Cement shipping volumes fall to 14% of the total in 1938, the last year before the war.

The military government of the American Occupation Zone dismisses the Board and appoints three trustees – including Dr. Ehrhart Schott, who is later restored as Chairman. For his inexhaustible drive and inventiveness, Dr. Schott becomes a legend within the company.