What is a critical safety check prior to propane filling?

A visual inspection for leaks is a critical safety check prior to propane filling because it ensures that the tank and its associated equipment are in good condition and free from any leaks or potential hazards. Propane is a flammable gas, and any leaks can pose serious risks, including fire and explosion. Visually inspecting the tank and connections allows the operator to identify any signs of wear, damage, or corrosion that could result in leakage.

In terms of the other options, weighing the tank helps in determining the amount of propane it can safely hold, but it does not directly address safety concerns related to leaks. Checking the temperature of the gas is not a typical requirement before filling. Additionally, determining the ownership of the tank is important for legal and regulatory reasons, but it does not directly mitigate safety risks associated with filling the tank. Therefore, conducting a visual inspection for leaks is the most essential safety measure prior to filling a propane tank.