Tanker trucks carry flammable liquids like fuel and chemicals, and one small feature helps keep them safe:

the metal chain hanging from the back or side. This isn’t for decoration—it’s a grounding chain, and it plays a vital role.

As the truck moves, friction from the liquid inside can build up static electricity. If not discharged,

that static could spark—potentially causing a fire or explosion, especially with flammable cargo.

The grounding chain drags along the ground, safely releasing built-up static electricity into the earth.

It’s a simple, low-tech solution that’s crucial for safety.

After accidents caused by static discharge, agencies like the Department of Transportation (DOT) began

requiring grounding chains on fuel and chemical tankers. They’re regularly inspected, and trucks can’t operate if the chains are missing or damaged.

While some modern trucks use reels or anti-static additives, the traditional chain remains widely

used because it’s cheap, reliable, and doesn’t rely on electronics.

So next time you see a chain dragging behind a tanker truck, remember—it’s doing a quiet but critical

job: preventing disaster and protecting lives with every mile.