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

In addition to the distinctive, sulfur-like odor of mercaptan, look and listen for any of the following:

• Continuous bubbling in water
• A hissing, whistling, or roaring sound
• Dead or dying vegetation (in an otherwise moist area) over or near a pipeline
• Dirt or water being thrown into the air
• A damaged connection to a gas appliance
• An exposed pipeline after an earthquake, fire, flood, or other disaster