Gas Additives in the 1980s

Fuel additives in the 1980s improved efficiency but had unintended drawbacks.

Gasoline has powered the internal combustion engines of automobiles since the invention of the car. For just as long, fuel makers have mixed additives or have added chemicals and other substances to gasoline. Many of these additives help cars process fuel more efficiently without damaging the engine or the exhaust system. In the 1980s, the primary fuel additives were tetraethyl lead, lead scavengers, methyl tertiary-butyl ether and ethanol.

Tetraethyl Lead

Today, many gas stations sell “unleaded” gasoline because gas used to contain lead in the form of tetraethyl lead, or TEL. A pure mixture of air and gas in a car engine’s cylinder does not burn efficiently and causes detonation or “knocking” in the engine. For this reason, fuel companies started adding TEL to gasoline as early as 1923. However, cars leaked TEL back into the environment through vehicles’ exhaust systems, and lead also damaged the catalytic converters designed to control pollution. Lead is toxic to humans, causing developmental problems in infants and children and neurological and pulmonary disorders in children and adults. In the 1970s, many states and the federal government began passing regulations against leaded gasoline. The use of this type of fuel additive steadily decreased through the 1980s.

Lead Scavengers

In the 1980s and throughout the period of use of leaded gasoline, fuel companies added compounds known as lead scavengers to leaded gasoline. These chemicals included ethylene dibromine and ethylene dichloride. The lead used in gasoline prevented engine knocking but also caused problems, including the formation of lead deposits inside the engine. Over time, lead deposits could break off and clog valves, reducing fuel efficiency. Lead scavengers in gasoline helped break down these deposits. However, like lead, the scavengers also leaked into the environment.

Methyl Tertiary-Butyl Ether

According to Martin V. Melosi, lead use in gasoline in the U.S. had declined by 99 percent as of 1988. Companies began to replace lead with methyl tertiary-butyl ether, or MBTE. This chemical prevents knocking and, unlike lead, does not damage a car’s catalytic converter. It also provided a cheap alternative to lead. MBTE helped fuel burn more cleanly and, as a type of chemical called an oxygenate, it added oxygen to gasoline, which increased the energy available to the engine. However, as with lead, scientists soon determined that MBTE was toxic to humans. Cars leaked MBTE into the environment, where it began appearing in groundwater. Scientists later discovered that MBTE caused cancer in laboratory animals.

Ethanol

In the 1920s, Henry Ford’s Model A car had a dashboard switch that let the engine change from running on gasoline to burning ethanol. Ethanol is made from plants such as corn. The gasoline shortage crisis in the late 1970s encouraged oil companies to add between 5 and 10 percent ethanol to fuel. Companies continued using ethanol as an fuel-additive alternative to MBTE in the 1980s. Ethanol is an alcohol and also an oxygenate, letting gasoline burn more efficiently while also adding energy to boost the octane rating of gas. It also reduces the emission of environmental pollutants such as hydrocarbons, which damage the ozone layer. However, ethanol has its own drawbacks, including raising the price of corn diverted from use as food to production of fuel.

References

• The Globalist: A Tale of Three Additives (Part I)
• The Globalist: A Tale of Three Additives (Part II)
• Running on Alcohol: What is Ethanol
• Environmental Protection Agency: Methyl Tertiary Butyl Ether (MTBE)
• Environmental Protection Agency: Lead Scavengers Historical Uses
• Environmental Engineering Blog: Lead Scavengers
• Automobile in American Life and Society: "The Automobile and the Environment in American History"; Martin V. Melosi
• Volkswagen Resource Page: Fuel Additives