What might occur if a forklift is refilled with the engine running?

Refilling a forklift with the engine running poses a significant safety risk, as it can lead to a fire. Forklifts typically operate using flammable fuels or batteries, and the presence of a running engine increases the risk of ignition from sparks or heat generated during refueling. Any fuel vapors released during the refilling process can easily ignite if the engine is not turned off. This is why safety protocols in operating procedures emphasize the importance of turning off the engine before refueling, to mitigate the risk of fire and ensure a safer working environment.

Other potential outcomes listed do not capture the critical safety hazard related to refueling. For instance, while an engine stalling might happen under certain circumstances, it does not present a serious immediate risk like a fire. Efficiency in refilling is not improved with the engine running; in fact, it can make the process more dangerous. Load shifting could potentially occur due to other unrelated factors but is not a direct consequence of refueling with the engine on. Therefore, the focus on preventing fire emphasizes the importance of adhering to safety standards in forklift operation.