With the increasing threat of war, the Army made significant changes to the organization of chemical warfare in the mid-1930s. One of them was the establishment of chemical units in the Army – the 401st artillery unit in Olomouc and later the sanitation patrols and sanitation companies, whose task was chemical reconnaissance, the detection of warfare agents and the decontamination (sanitation) of terrain and equipment. The Military Chemical Institute, namely the gas service, was also involved in the organisation of protection against chemical agents for the civilian population and tested civilian gas masks in addition to military ones. At the direct instigation of the Ministry of National Defence, Fatra Napajedla was founded by the Bata Corporation in 1935. It also produced civilian masks, but it was far from being the only company that provided anti-chemical equipment. Other well-known manufacturers were Chema Lutin, Kudrnac, Optimit, and others.