• Brown or discolored vegetation amid healthy plants
• Dirt being blown into the air
• Colorful sheens on water surfaces
• Fire at or below ground level
• Stains or pools of hydrocarbons not usually present in the right-of-way
• Bubbles coming from bodies of water
• A loud roar or hissing sound
• Distinctive petroleum type odors or the smell of mercaptan or sulfur (rotten eggs)
• A dense white cloud or fog

On occasion, a pressure-relieving device may activate at an aboveground pipeline facility. These devices are acting as designed to relieve pressure on the system to prevent over pressurization.

Under no circumstances should a pressure relieving device be capped or valved-off.