In fact a natural gas outage of 300 households is an extremely rare event. This area s natural gas system is vulnerable to earthquake damage, third party damage and landslide damage. Earthquake damage could include a catastrophic systems failure in which ground movement causes a pipeline to sever allowing gas to escape. Natural gas companies are less concerned with gas escaping in wild settings, where life and property are not threatened. This is because natural gas is lighter than air and will quickly dissipate, minimizing risks.
Gas escaping into buildings or heavily populated areas is a bigger concern.
The current infrastructure does include control valves for shutting down pipelines in the event of such problems. Third party damage is the most common natural gas related problem. This damage typically occurs when contractors dig into gas lines. Puget Sound Energy works closely with local fire departments in responding to these incidents. Additionally, they are training contractors in system design so that they will be more aware of where pipelines are likely to be.