While drums are generally being used to safely contain hazardous liquids, the drums themselves also need to be safely contained within a storage unit; after all, when you are handling toxic chemicals, a little extra safety will never hurt. When it comes to drum storage large units are what you need, at least if you are looking at an industrial-sized job.
In any case, they have two drum storage large units available at the moment, the Drum & IBC Storage, and the Drum Storage Vault. The former is made from RHS frame galvanised sheet cladding, is weather-proof, contains pad-lockable sliding doors, not to mention that it comes with benches and spill trays. It has a capacity of 780 litres for drum storage, and 1200 litres for sump flooring. The latter model is also weather-proof, contains two removable shelves, 3-point lockable reinforced doors for optimum security, with a sump capacity of 260 litres. All in all, it's heavy duty stuff and can cater to all your drum storage needs.