What is the minimum psi in an oxygen tank?

• A. 100 psi
• B. 200 psi
• C. 300 psi
• D. 400 psi

Answer: (B)

Oxygen cylinders are high‑pressure containers, and the regulator that delivers the gas relies on a minimum pressure to meter flow reliably. In EMS practice, you don’t want to rely on a cylinder once its gauge drops to about 200 psi because at or below this level the flow becomes unreliable and you risk running out in the middle of patient care. So the minimum recommended pressure to continue using the cylinder is 200 psi. A full cylinder sits around 2000 psi, and as you use oxygen you monitor the gauge to know when to switch cylinders to maintain uninterrupted delivery.