that is probably true in your country my friend
but its all too often the things that people aren't aware of are the ones that can hurt them most!
general rules for storing pyrotechnics phosphor compounds kept dry and cool and well away from explosive type fireworks
flares, roman candles, sparklers, and rockets need to be stored in sealed room capable of co2 flooding
mixed types of fireworks should never be stored together for extended periods of time
explosive types should be stored in an underground bunker or facility
It is true here, and I am not your friend!
Your rules are obviously very different from ours.
CO2 is useless with fireworks as they all contain oxidising agents and once lot will continue to burn without added oxygen, even underwater.
Standard storage is in ply lined steel shipping containers with earth electrodes connected to opposite corners for lightning protection. They must be mounted on solid level bases or sleepers etc.
All fireworks stored in approved boxes with UN markings.
Net explosive quantity in any container must not exceed the licence.
1.4s 1.4g and 1.3g can be stored together but 1.1g (8" shells and upwards) goes into separate storage.
Storage capacity can be increased by mounded earthworks surrounding the site, underground storage can also get a bigger licence.
There are also rules about distance from roads , houses, businesses, airports, petrol stations etc etc.