Most natural gas emergencies occur when:

The occurrence of most natural gas emergencies can indeed be closely linked to situations where both a pilot light has gone out and a thermo-coupling has failed. A pilot light is essential for appliances that use gas, as it ignites the gas when it is released. If the pilot light goes out, there’s a risk of unignited gas accumulating, which can lead to an explosive environment.

The thermo-coupling plays a critical role by detecting whether the pilot light is active. If it fails while the pilot light has already gone out, it may allow gas to continue flooding into the appliance without an ignition source, further increasing the risk of a dangerous situation.

This combination of failures creates a high-risk scenario for gas accumulation, leading to potential explosions or fires, and is therefore considered a significant aspect of natural gas emergencies. Other situations listed might pose risks but typically do not lead to the same level of emergency as the simultaneous failure of the pilot light and thermo-coupling.