What type of hazard involves pressurized containment vessels and potentially flammable hydraulic oil?

The correct answer identifies a specific type of hazard related to pressurized systems that contain fluids, such as hydraulic oil. Hydraulic hazards are primarily associated with the risks posed by high-pressure hydraulic systems, which can lead to serious accidents if not properly managed. This can include issues such as leaks that could result in flammable oil being released, posing fire risks.

Understanding hydraulic hazards is crucial for safety in environments where hydraulic systems are present. Such systems require careful monitoring and maintenance, as well as a thorough understanding of pressure limits and proper handling practices to prevent catastrophic failures. This includes knowledge of the properties of hydraulic fluids, the functioning of hydraulic components, and the necessary precautions to take when working with or near these systems.