Today, Łęgnowska, Nowotoruńska, Hutnicza, Chemiczna streets and the internal road network of the former Zachem chemical plant run on the ancient DAG factory area.

The afforestation and the distance from the city have preserved the facility during and after the war, thus keeping secret the location and the security of the chemical and explosives production activities carried out here.

[2] The western part (German: DAG Kaltwasser, Polish: Zimne Wody or cold waters), code name Torf (Peat) was dedicated for the production of gunpowder and its derivatives: The Eastern part (German: DAG Brahnau, Polish: Łęgnowo), code name Kohle (Coal) was intended for the production of blasting explosives to be incorporated into missiles, mines and bombs: The two main areas (Kaltwasser and Brahnau) were linked by one road, which ran on a viaduct over the coal main railroad near the station of Bydgoszcz-Żółwin, disused today.

Such terrain had a beneficial effect on the set-up of factory buildings: small valleys separating sandy ridges ensured the isolation of the edifices, even in case of an accidental explosion.

Thus, most of the explosive and gunpowder of the Nazi war machine have been produced by DAG and Westfälisch-Anhaltische Sprengstoff-Actien-Gesellschaft (or WASAG) and their subsidiaries, such as DAG-Verwertchemie and WASAG-Deutsche Sprengchemie.

The Wehrmacht Supreme Military Command had issued, as early as September 1939, a staff order intending to identify places in the Polish annexed territories where to build gunpowder and explosives factories.

Underground networks consisted of:[4] Surface pipelines were dedicated for: As far as energy supply was concerned, two combined heat and power plants and two boiler houses were constructed in 1940.

Each stage of the production process was taking place in separate, usually small, buildings and the movements between them were realized by means of surface (roads) and underground (tunnels) systems.

In spring 1944, a wooden, night-lit mock-up factory was even erected, located 2 to 3 km south of the real plant, in order to confuse allied pilots during air raids.

On the other hand, bunker-type buildings, used when explosion risk was assessed as high, consisted of quadrilateral edifices with three walls and a thick reinforced concrete ceiling.

In this case, the architectural concept directed the blast to the fourth side, i.e. an exhaust wall made of wood and glass, the debris being blocked by the earth embankment located behind.

[1] As for the protection and safety of the project, additional efforts were deployed, such as: Plant security, employee control and fire service were supervised by the company guards (German: Werkschutz).

Plant production began in 1941, with the position of director taken over by Adolf Kämpf (1879-1957), an experienced chemist, graduate from the Technical University Stuttgart[5] and the facility integrated on November 1, to the DAG-Verwertchemie complex.

In February 1944, Wehrmacht High Command commissioned an extension of the existing lines and the construction of new manufacturing capacities for blasting explosives and rocket powders: In October 1944, the threat of Soviet seizing of the complex ground to a halt some of these projects (expansion of TNT, dinitrobenzene and gunpowder zones).

Although there is no precise data on weapon handloading, it was a strategically important activity: in particular, shells for machine guns were produced in Bydgoszcz metallurgical plants, such as the former Fiebrandt railway signal factory at 32 Grunwaldzka Street.

It is assessed that a 1944 daily production of powder dough from the NGL line was enough to satisfy the manufacture of the following assets:[1] On December 1, 1942, about 10000 people were working in the DAG Bromberg factory.

On July 15, 1944, more than 1000 Jewish women from the Stutthof concentration camp were sent to the plant to work on ammunition handloading and at Bydgoszcz East railway station.

[4] To accommodate non-local workers, 18 camps were built, consisting of around 100 wooden and 150 brick barracks (at present day Wojska Polskiego avenue, Hutnicza street and in the Glinki district).

In 1940, a local underground army group (ZWZ or Polish: Związek Walki Zbrojnej) was established at DAG Bromberg, led by Henryk Szymonowicz (aka Marek).

The most elaborate sabotage action (the largest in Pomerania) was called Operation Krem: carried out on March 23, 1944, it caused an explosion that killed German engineers working on the development of the factory.

Darzbór was dealing with the intelligence within the DAG Bromberg complex, helping POWs, sabotaging Bydgoszcz Emilianowo railway station, hiding and transferring RAF officers and running guerrilla activities.

In a remote and secret part, expanded in 1943- 1944, were developed unprecedented missiles, inflated with compressed air, which blast radius neared 2 kilometres (1.2 mi).

After WWII, at the behest of the Soviet War Trophy Commission, all technical equipment was gradually dismantled and transported to the USSR by the Red Army.

Between 1300 and 1500 rail trucks were necessary to ship the whole DAG equipment, probably to Ukraine: the freight included massive components, such as the CHP plants or the boiler houses.

Administered by the Central Management of Arms industry in Warsaw, the complex was now watched by the Internal Security Corps or KBW for Korpus Bezpieczeństwa Wewnętrznego.

The Zachem plant used part of the existing infrastructure for civilian production, but also carried out secret manufacturing of explosive for the armies of the Warsaw Pact.

Some of the ex-German buildings not re-used were crushed with explosives and the rubble was removed and tossed into the marshy bed of the Brda river estuary to the Vistula.

[10] For many years, hundreds of buildings, connected by tunnels and masked in Bydgoszcz forest area, were explored in secret by lovers of technology and military history.

On the post-factory premises, multimedia and interactive exhibitions expose the history of the DAG complex, the place of the factory in the city and display military armaments and explosives.

In addition, various exhibitions explain the abuse of forced labor, the resistance movements with conspiracies and sabotage actions at the time in occupied Bydgoszcz.