Final answer:
The hazard particular to carbon dioxide fixed suppression systems is Oxygen depletion, which can cause hypoxia and potentially fatal consequences for humans, and can create dead zones in aquatic environments.
Step-by-step explanation:
The best description of a hazard particular to carbon dioxide fixed suppression systems is Oxygen depletion. These systems work by releasing carbon dioxide (CO2) to displace or reduce the level of oxygen in the environment, thereby extinguishing the fire. However, if this occurs in an enclosed space where people are present, it can lead to a dangerous decrease in ambient oxygen levels, potentially causing symptoms of hypoxia, such as fatigue, headaches, and confusion. It's important to consider this risk when using CO2 systems, as severe oxygen depletion can result in unconsciousness or even death. Furthermore, aquatic systems can suffer similar effects known as eutrophication, leading to a dead zone where there is too little oxygen to support most marine life due to the overgrowth of microorganisms.