Which of the following describes a safety hazard in ammunition storage?

High temperature storage poses a significant safety hazard in ammunition storage due to the potential for increased pressure within ammunition casings and the risk of propellant deterioration. When ammunition is exposed to elevated temperatures, the chemical composition of the propellant can become unstable, leading to the possibility of cook-off incidents where the ammunition may ignite unexpectedly. Additionally, high temperatures can accelerate the aging process of ammunition, thereby compromising reliability and safety over time.

In contrast, low humidity environments, stable storage conditions, and secure storage facilities are typically associated with optimal storage practices. Low humidity helps to prevent corrosion of the ammunition components, while stable storage conditions refer to maintaining consistent temperatures and humidity levels that promote the longevity and reliability of the ammunition. A secure storage facility is critical for preventing unauthorized access and ensuring that the ammunition is stored safely from potential theft or damage. Thus, high temperature storage is recognized as a clear safety hazard in the context of ammunition storage, making it the correct choice.