Why Tanker Trucks Have an Extra Chain: A Crucial Safety Feature

Tanker trucks, used to transport liquids like fuel and chemicals, often have a chain hanging from the rear. Though it may appear insignificant, this chain serves a vital safety function — grounding the truck to prevent static electricity buildup. As flammable liquids slosh inside the tank, friction can generate static charges. If not discharged, these charges can spark and ignite vapors, causing deadly explosions. The dragging chain provides a path for this static to safely dissipate into the ground.

This practice became standard after historical accidents highlighted the dangers of static discharge. Today, safety regulations, such as those by the U.S. Department of Transportation, require grounding systems like this chain. While modern methods, including grounding reels and anti-static additives, have emerged, chains remain widely used for their reliability and simplicity.

Misconceptions persist — some believe the chain is decorative or outdated — but it’s still a regulated, functional part of truck safety. Regular maintenance ensures the chain remains effective and in contact with the ground.

Ultimately, the grounding chain is a small but essential element in preventing accidents during fuel transport, protecting drivers, the public, and the environment.