Final answer:
A safety valve prevents pressure buildup that could cause an oil spill by opening to release excess pressure when it exceeds a set limit.
Step-by-step explanation:
Pressure buildup which would cause an oil spill is prevented by a safety valve. A safety valve is designed to open and relieve excess pressure from vessels or equipment and then close again. It is essential for protecting the equipment from damage and preventing potential hazards such as oil spills. This valve is calibrated to open when the pressure exceeds a predetermined limit. The function of a safety valve is critical in maintaining the integrity of a pressurized system and ensuring the safety of the operation.