When a white mist appears from the fixed maximum liquid level gauge while filling a mobile motor fuel or RV tank, immediately shut off the

• A. fixed maximum liquid level gauge
• B. collar
• C. check for leaks with non corrosive leak detector solution
• D. hose end valve

Answer: (D)

When you see a white mist coming from the fixed maximum liquid level gauge while filling, it means liquid propane is reaching the vapor space and is rapidly boiling off, signaling an overfill risk. The safest immediate action is to shut off the hose end valve. This stops any more liquid from entering the tank right away, helping to prevent spills or excess vapor release. The gauge simply indicates the limit, but it does not automatically stop flow, so relying on it alone isn’t enough. The other options don’t provide the immediate control needed to halt the fill; they’re not actions that stop the flow at this moment.