Why it cannot operate in areas with an excess of oxygen

An oxygen content of over 40% can cause oxygen poisoning and increase the risk of fires in surrounding flammable materials

When a person is in an environment with pure oxygen at a pressure greater than 0.05 MPa (half an atmosphere), it is toxic to all cells; prolonged exposure can lead to \"oxygen poisoning\". The pulmonary capillary barrier is damaged, leading to pulmonary edema, pulmonary congestion, and bleeding, which severely impairs respiratory function and subsequently causes hypoxia in various organs, resulting in damage to them. In a pure oxygen environment at 0.1 MPa (1 atmosphere), a human can survive for only 24 hours before developing pneumonia, which ultimately leads to respiratory failure and death by asphyxiation. A person can remain in an environment of high-pressure pure oxygen at 0.2 MPa (2 atmospheres) for up to 1.5 to 2 hours; exceeding this time limit can cause brain poisoning, disruption of the body’s physiological functions, mental confusion, and loss of memory. If oxygen at a pressure of 0.3 MPa (3 atmospheres) or even higher is introduced, human brain cells will undergo degeneration and necrosis within minutes, leading to convulsions, coma, and death. 　 Furthermore, excessive oxygen intake can also accelerate the aging of living organisms. Oxygen that enters the body reacts with oxidases in cells to produce hydrogen peroxide, which then turns into lipofuscin. This lipofuscin is a harmful substance that accelerates cellular aging; it accumulates in the heart muscle, causing the heart muscle cells to age and leading to a decline in cardiac function ； It accumulates on the blood vessel walls, causing the vessels to age and harden ； It accumulates in the liver, weakening its function ； It accumulates in the brain, leading to a decline in intelligence, memory loss, and dementia ； They accumulate on the skin, forming age spots. 　　Effects of hypoxia and hyperoxia on the human body:
Oxygen concentration (% by volume), symptoms (at atmospheric pressure):
>23.5%: Hyperoxia; high risk of explosion.
20.9%: Normal oxygen concentration.
19.5%: Minimum allowable oxygen concentration.
15–19%: Reduced work efficiency; may cause problems in the head, lungs, and circulatory system.
10–12%: Rapid breathing, loss of judgment, purple lips.
8–10%: Loss of intelligence, fainting, unconsciousness, pale complexion, purple lips, nausea and vomiting.
6–8%: Fatal within 8 minutes at 100% concentration; fatal within 6 minutes at 50% concentration; recovery possible with treatment within 4–5 minutes.
4–6%: Seizures within 40 seconds, respiratory arrest, death

There are three reasons: one is the toxicity to the human body in the presence of oxygen-rich conditions； Second, oxygen enrichment can easily cause fires ； Third, in an oxygen-rich environment, the conditions are highly oxidative, and reducing substances will denature in such an environment.

When working in such an environment for a long time, lung capacity decreases, and returning to normal air conditions can cause discomfort in the lungs； The same is true in reverse.