Oxygen cylinder content.  Oxygen cylinder content An oxygen cylinder typically contains compressed oxygen gas at high pressure. The amount of oxygen in the cylinder can vary depending on its size, but it is usually measured in cubic feet (ft³) or liters (L). Medical oxygen cylinders, for example, can come in sizes ranging from small portable cylinders with 2 liters of oxygen, to large stationary cylinders that hold several thousand liters of oxygen. The pressure at which the oxygen is stored inside the cylinder can also vary, but typically ranges from 2000 to 3000 pounds per square inch (psi). It is important to note that oxygen cylinders are considered hazardous materials and should be handled and stored with care to prevent accidents or leaks. It is also crucial to ensure that the oxygen in the cylinder is of a high purity and meets safety standards.