In spring 1940, by personal order from general "Grot" Rowecki, major Mieczysław Chyżyński ps. (pseudonym) "Pełka" appointed a group of PWPW employees, under second lieutenant Czesław Lech's ps. "Biały" command, with an underground name PWB/17, who printed banknotes and other documents for the needs of the Home Army and sabotaged the activities of the German management of the Company. The Printer Company employees who joined the group swore an oath before a Cross, which – saved by Czesław Lech's wife after the Warsaw Uprising – was carefully cherished in lieutenant "Biały's" family ever since. By the end of 1942, in view of the growing threat of exposure, this action was ceased, however during 2 years over a dozen million zlotys were delivered for the needs of the Home Army. By order from the Chief Commandant of the HA dated 30 December 1942, 11 persons were awarded the Gold Cross of Merits with Swords and 17 persons received the Silver Cross of Merits with Swords.
During the Warsaw Uprising the PWB/17/S as an autonomous battle group, supported by HA groups attacking from outside, took control of the PWPW S.A. building on 2 August 1944. For 27 days the PWPW S.A. building was one of the main centres of resistance of the insurrectionary Old Town. Under fire from the ground and air The Printer was defended – apart from the PWB/17/S – also by company "Osa" – since 10 August, on 21 August the main burden of defence was taken over by group HA "Leśnik", and for the last day of defence they were assisted by platoon "Sarmak" – over 600 persons all in all. The staff of the insurrectionary Printer defended themselves till 28 August 1944. During evacuation i.a. lieutenant "Biały" was killed, he commanded those who remained from group PWB/17/S. In the Printer basement, in the hospital arranged there, about 30 seriously wounded insurgents remained, with doctor Hanna Petrynowska - "Rana", who took care of them. They were all brutally killed by the German troops coming in.