Which of the following is a common sign of a gas leak?

The presence of an acrid smell is a well-known indicator of a gas leak. Natural gas is odorless in its pure state, but safety regulations require the addition of a chemical called mercaptan, which gives it a distinct rotten egg smell. This smell is crucial for detecting gas leaks quickly and effectively, as gas accumulation can lead to dangerous situations, including explosions or asphyxiation.

While high pressure readings on a gauge or low efficiency in appliances may suggest issues within the gas system, they do not directly indicate a leak. Similarly, corrosion on pipes may signal deterioration or potential failure points, but it is not an audible or olfactory warning sign like the acrid smell associated with gas leaks. The distinct smell serves as a readily noticeable cue that prompts immediate investigation and action to ensure safety.