If you’ve ever driven behind a fuel tanker, you may have noticed a short chain dragging along the pavement near the rear of the truck. At first glance, it looks like a loose piece of hardware or an oversight. But in reality, that chain is a critical safety feature—an understated yet powerful safeguard designed to prevent disaster.

Fuel tankers are engineered to carry volatile liquids and gases—gasoline, diesel, chemicals, even food-grade products like milk or corn syrup. Their design prioritizes containment and safe delivery. But one invisible hazard is always present: static electricity.

As a tanker moves down the road, friction from the liquid sloshing inside, along with vibration and airflow, generates static charges. Left unchecked, these charges can build to dangerous levels. A single spark near fuel vapors could trigger a fire or even an explosion.