A chemical carbon dioxide gas generator comprising: - a charge housing; - a carbon dioxide gas penetrable charge, contained in the said housing, the charge comprising a) 40-60 wt. % of a substance which upon decomposition generates carbon dioxide, which substance is selected from the group of magnesium carbonate, other carbonates, magnesium oxalate and other oxalates, b) 20-50 wt. % of an oxidiser selected from the group of sodium chlorate, potassium chlorate, lithium chlorate, other metal chlorates, sodium perchlorate, potassium perchlorate, lithium perchlorate, and other metal perchlorates, c) 1-20 wt. % of carbon or another fuel, d) 1-10 wt. % binder, said components a), b), c) and d) together forming 90-100 wt. % of the total weight of the charge; - an ignition device for igniting the charge; - a carbon dioxide gas treatment unit for reducing the content of one or more side-products - which may have been formed by the charge - in the generated carbon dioxide, and / or for cooling carbon dioxide gas generated by the charge; and - an outlet for carbon dioxide gas generated by the charge.