In case it was originally allotted as agricultural land, its use should have beenconverted to residential. You can convert agricultural land into residential or industrial land by paying a fee. You have to apply to the commissioner of the land revenue department, explaining the purpose of conversion. You can get a 'change of land use' after obtaining the necessary approval from the local authorities
Once i is agricultural land, it should be duly permitted first for conversion and then permitting construction and further usage shifts to another authority. Whether one can get permission for LPG or not depends on the discretion of authority, that has to look into practical aspect of such hazards.