The workforce consisted of a mixture of German specialists and forcibly conscripted Frenchmen from the "Service du Travail Obligatoire" (STO). They were supplemented by Belgian, Dutch, French, Polish, Czech and Soviet prisoners of war and civilian conscripts, who were used as slave labour. The labour force also included many French political prisoners and Spanish Republicans who had fled to France after General Franco's victory in the Spanish Civil War but had then been interned by the invading Germans. The non-German workers lived in two camps officially known as Organisation Todt Watten "Zwangsarbeitslager" 62 (Forced Labour Camp 62) about distant from the site, near the village of Éperlecques.