Two men died in Kapfenstein, also in Styria, after making firecrackers in an outbuilding next to their family home.
Police were told about the disused chicken barn in Oedt by several concerned neighbours who knew that it was packed with boxes of explosives.
Police found "serious deficiencies" there and have charged the owner, who did not have approval to store such a large quantity of dangerous materials on his property. The explosives included fireworks which were ready to be sold and were not homemade, according to the Austrian Press Agency.
Anyone could have accessed the barn as the doors were left open and it was often deserted. A temporary car workshop had also been set up in the barn, where car parts were being sanded down and spray painted. Police said they also found leaking oil tanks and trails of petrol dangerously close to the boxes of explosives. The electrics were also in a neglected and dangerous condition.
The supplier of the explosives has also been charged. Police said there was no connection to the amateur pyrotechnicians who died in Kapfenstein.