What Happened to Leaded Gasoline?

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Leaded gasoline was once the standard for automotive fuel. Every vehicle required it, and using unleaded fuel would damage these early motors. But by the 1970s, oil companies began discontinuing the production of leaded gas for obvious reasons. But what if you have a classic car and need leaded fuel? Can you still buy it? Yes—here’s how to find leaded gas, and what caused the end of this once ubiquitous fuel.

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Why was Lead Added to Gasoline?

Initially, lead was used in gasoline as an anti-knock agent. Early gas engines tended to knock and destroy themselves with use, but automakers discovered that increasing fuel octane could mitigate these issues.

Tetraethyl Lead

At the time, there were two primary methods of increasing the octane level of gasoline. The first was to produce a costlier and higher-quality fuel, which companies obviously wanted to avoid.

Then in 1921, General Motors engineers discovered that they could increase the octane of gas by adding a chemical called tetraethyl-lead. Tetraethyl-lead was cheap, easy to make, and enormously beneficial to gasoline engines.

Benefits of Leaded Fuel

Automakers would eventually discover that tetraethyl-lead also provided numerous other benefits to gasoline engines. For one, it reduced knock—which was the primary goal. It also helped reduce wear-and-tear on valve seats and other internal components. Leaded fuel made gas engines run better and longer with less maintenance and parts wear.

It’s Toxic: Hazards of Leaded Gasoline

It shouldn’t be difficult to imagine that burning liquified lead isn’t good for the environment. In fact, the use of leaded fuel might be one of the biggest environmental disasters of the 20th century. Its effect on the health of millions (especially children) was catastrophic, and the effects are still with us today.

The biggest problem with leaded fuel is its exhaust. Lead is a heavy metal and tends to hang around long after the carbon monoxide and other exhaust gasses have dissipated into the atmosphere. After a few decades of motoring, measurable quantities of lead clung to American streets, sidewalks, walls, and waterways. When it rained, lead deposits from the road would wash into local freshwater supplies, effectively poisoning the entire ecosystem.


Lead was one of the reasons why smog in the 1970s (like the one in Cleveland above) was such a big health hazard. Lead poisoning, which was once reserved for people who worked in very specific industries (mining, plumbing, manufacturing, and so on), became a nationwide phenomenon. Many studies have been conducted, and some claim that lead dust pollution from gasoline caused between 200-650 annual premature deaths per million men in the population.

EPA Phases Out Leaded Gas

By the 1970s, the use of leaded gas was already in question in the United States. But the country didn’t fully phase out the product until 1996. The remnants of lead gasoline use are still dotted around the U.S. Many gas stations in rural areas still use pumps labeled, ‘Warning: Contains Lead,’ even when no leaded fuel is dispensed. The EPA officially announced the phase-out of leaded fuel in 1973, shortly after the passage of the first U.S. Clean Air Act.

Additionally, early emissions-control systems couldn’t accommodate leaded fuels. So by 1975, new cars fitted with SMOG equipment were required to run on unleaded only. The ‘smog parts’ on the short-lived Oldsmobile 403 engine are an excellent example of what these temperamental early emissions systems were like.

Where to Get Leaded Gasoline

So can you still get leaded gasoline for a classic car? Actually, you can—leaded fuel is still manufactured for the American market, despite being officially banned by the EPA in the 1990s. Leaded gasoline is technically illegal for on-road use. However, suppliers can sell leaded fuel for race cars, off-road-only vehicles, aircraft, and other specific non-road uses.

Leaded gas is often available through specialized fuel suppliers and some local owner-operated gas stations. It’s typically stored in small quantities (in 55-gallon drums) and kept out of sight. Contacting your local racing fuel supplier is the best first step to obtaining leaded gas for off-road use.

Alternatives and Lead Substitutes

Leaded fuel is much harder to come by than it used to be. Many former suppliers have stopped selling it, and restrictions on leaded gas make it difficult to justify using. Most engines now have hardened valve seats and fewer knocking problems, which makes leaded fuel completely obsolete in most circles.

However, if you want to drive a vehicle designed for leaded gas, you’ll need to get a fuel additive to prevent damaging your motor with modern fuel. There are numerous lead substitutes available at a low cost, and many are sold at chain auto parts stores. These chemicals protect sensitive engine parts by increasing the octane of fuel, thus mimicking the effect of tetraethyl-lead.


Joshua Weinstein

Joshua Weinstein

I rebuild & restore classic cars and trucks when I'm not researching and writing about all things automotive. My current project is a 1978 Ford.

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