Granular fertilizer kept dry should still be usable and flow through a spreader. The bag that has moisture in it is likely very caked together and would need to be broken apart and likely not suitable for the spreader. While we would not know the effectiveness of that damaged bag, broken up bits could be added to the compost pile every so often and a good use of it and a way to "dispose' of it properly. I assume this is just fertilizer without any weed control properties. Other uses would be in landscape beds, perennial flower beds and depending on the analysis, worked into the vegetable beds.