The Gasplane was introduced on 15 March 1939 by Heeresmitteilung 210 and initially it had two official purposes. Firstly, as a defence against liquid gases dropped out of an aircraft and secondly to cover poisoned terrain. Army regulations stipulated that the Gasplane had to be carried in the field in addition to the Gasmask and be ready for use.
In August 1941 a further use for the Gasplane was announced, it’s use in fire fighting. Further information can be found here.
The standard Gasplane could only be used once, a later variant made for Tropical and Arctic environments could be reused.