How does an operator ensure safety concerning fuel vapors before engine start?

Ensuring safety concerning fuel vapors before starting an engine is crucial to prevent the risk of explosion or fire. Running an exhaust blower is the correct practice in this scenario because it helps to ventilate the engine compartment, thereby removing potentially harmful and flammable vapors that may have accumulated. This action decreases the concentration of fuel vapors in the air, reducing the risk of ignition when the engine is started.

Other options, while related to general boating practices, do not directly address the specific concern of fuel vapor safety. Checking the oil level is important for engine maintenance, but it won't mitigate the risk of vapor ignition. Inspecting the hull is critical for overall vessel integrity and safety, but it does not affect the presence of fuel vapors. Repositioning the anchor may be relevant to anchoring safety but has no impact on fuel vapor concerns. Thus, running an exhaust blower is the focused, effective strategy for ensuring safety prior to engine operation.