Which of the following control techniques involves releasing liquefied compressed gas vapors into the atmosphere to reduce tank pressure?

The correct answer is venting, which is a control technique used in hazardous materials situations, particularly when dealing with liquefied compressed gases. Venting allows the controlled release of vapors to the atmosphere, facilitating a reduction in pressure within a tank. This practice is essential when there's a risk of over-pressurization, which might lead to a breach or explosion.

Venting is often utilized as a safety measure to stabilize a tank that contains hazardous substances, thereby preventing potential incidents. The method must be executed carefully and in accordance with safety protocols to ensure that the released vapors do not pose a health risk to personnel or the surrounding environment.

In contrast, techniques such as pumping are designed for transferring liquids from one container to another, absorption involves the uptake of vapors or liquids by a solid or liquid material, and encapsulation refers to enclosing or isolating hazardous materials to prevent exposure. None of those techniques specifically involve releasing vapors into the atmosphere to manage tank pressure, making venting the clear choice for this situation.