OHST Practice Exam

What is indicated by a chemical's presence of oxygen when using a gas indicator?

1. Potential for fire

2. Presence of flammable gases

3. Oxygen starvation risk

4. Safe atmosphere for entry

The correct answer is: Oxygen starvation risk

The presence of oxygen is a critical factor when evaluating the atmosphere in enclosed or controlled environments. When a gas indicator reveals oxygen, it suggests that the environment has sufficient levels of this essential element which is crucial for human survival. In particular, when considering whether an atmosphere poses a risk for oxygen starvation, it is vital to maintain a balance of oxygen that supports life. An atmosphere with low oxygen levels can lead to hypoxia, which may threaten the health and safety of individuals entering that space. Thus, identifying the presence of oxygen through a gas indicator can help assess whether there is a risk of oxygen starvation for anyone exposed to that environment. Meanwhile, the other choices—like the potential for fire or presence of flammable gases—while relevant in discussions about oxygen, do not specifically follow from detecting oxygen's presence alone as they involve other environmental factors such as concentrations of flammable materials and the ignition source, which aren't necessarily indicated by just the presence of oxygen.