Once notorious for their risky design, pressure cookers have an interesting history. During World War II, Americans were encouraged to can their food, leading to a surge in the use of pressure canners. This trend continued after the war, creating a high demand for pressure cookers. However, the rapid production during this period often compromised quality and safety. A typical 1950s model, for example, had a single valve prone to clogging. This could cause the cooker's gasket to burst under extreme pressure, sometimes even ejecting the lid.