The outlets of medical gas terminal units are designed to prevent which hazard?

• A. Cross connection
• B. Backflow
• C. Contamination
• D. Gas leaks

Answer: (A)

The outlets are built to prevent cross-connection of different medical gases. Each gas outlet uses a non-interchangeable connector geometry and color-coding (often via Diameter-Index Safety System, or DISS) so that the wrong gas line cannot be connected to the wrong outlet. This physical and coding separation stops a misconnection that could deliver the wrong gas to a patient, which could be dangerous or life-threatening.

Other hazards like backflow, contamination, or leaks are addressed by separate features: backflow is managed with valves and check mechanisms, contamination control comes from clean handling and filtration in certain gas lines, and leaks are prevented by proper fittings and regular testing. But the primary purpose of the outlet design is to prevent cross-connection of gases.