Yes, at least half of these ladders for fire emergencies are for one-time use only. It is not really stated in the product descriptions as to why they can only be used once, but from our research, we have several conclusions concerning this issue. Once these ladders are deployed, they cannot be folded back into their original form. Being disposable also keeps the cost of these items to a minimum. The most credible answer is because of safety and liability issues. If the ladders were used in practice for fire drills and damaged, then they would not work properly when a real fire occurred. This would possibly cause the manufacturer to have liability from the occurrence.