I am not sure, that will be something only the manufacturer can answer. The filters I purchased have a 5 year shelf life. I am sure you can go past 5 years.. that said at a certain point they will break down, use your own judgement. The point I was trying to make, do not buy surplus filters and pay full price. A lot of government agencies etc. will dump their filters when they are close to expiration and restock. I noticed most of the CBRN filters on Amazon were almost expired, reviewers were complaining, some had gotten expired filters.