Response tactics for outdoor leaks differ from those for indoor leaks, as gas leaks from outdoor sources may involve higher-pressure pipelines.

Be alert for the distinctive, sulfur-like or rotten-egg odor of mercaptan as well as any of the following gas leak warning signs:

• Continuous bubbling in water
• Dirt spraying or blowing into the air
• Plants or grass dying for no apparent reason, even in a moist area
• An unusual hissing, roaring, or whistling coming from the ground or gas equipment