Why Lead Used to Be Added To Gasoline

Today I found out why lead used to be added to gasoline.

“Tetraethyl lead” was used in early model cars to help reduce engine knocking, boost octane ratings, and help with wear and tear on valve seats within the motor. Due to concerns over air pollution and health risks, this type of gas was slowly phased out starting in the late 1970’s and banned altogether in all on-road vehicles in the U.S. in 1995.

For a more detailed explanation of why lead used to be added to gasoline, it’s necessary to understand a little bit more about gasoline and what properties make it a good combustion material in car engines.  Gasoline itself is a product of crude oil that is made of carbon atoms joined together into carbon chains. The different length of the chains creates different fuels. For example, methane has one carbon atom, propane has three, and octane has eight carbon atoms chained together. These chains have characteristics that behave differently under various circumstances; characteristics like boiling point and ignition temperature, for instance, can vary greatly between them. As fuel is compressed in a motor’s cylinder, it heats up. Should the fuel reach its ignition temperature during compression, it will auto-ignite at the wrong time. This causes loss of power and damage to the engine. Fuels such as heptane (which has 7 carbon atoms chained together) can ignite under very little compression. Octane, however, tends to handle compression extremely well.

The higher the compression in the cylinders a car’s motor can produce, the greater the power it can get out of each stroke of the piston. This makes it necessary to have fuels that can handle higher compression without auto-igniting. The higher the octane rating, the more compression the fuel can handle. An octane rating of 87 means the fuel is a mixture of 87% octane and 13 percent heptane, or any mixture of fuels or additives that have the same performance of 87/13.

In 1919, Dayton Metal Products Co. merged with General Motors. They formed a research division that set out to solve two problems: the need for high compression engines and the insufficient supply of fuel that would run them. On December 9, 1921 chemists led by Charles F. Kettering and his assistants Thomas Midgley and T.A. Boyd added Tetraethyl lead to the fuel in a laboratory engine. The ever present knock, caused by auto-ignition of fuel being compressed past its ignition temperature, was completely silenced. Most all automobiles at the time were subject to this engine knock so the research team was overjoyed. Over time, other manufacturers found that by adding lead to fuel they could significantly improve the octane rating of the gas. This allowed them to produce much cheaper grades of fuel and still maintain the needed octane ratings that a car’s engine required.

Another benefit that became known over time was that Tetraethyl lead kept valve seats from becoming worn down prematurely. Exhaust valves, in early model cars, that were subject to engine knocking tended to get micro-welds that would get pulled apart on opening. This resulted in rough valve seats and premature failure. Lead helped fuel ignite only when appropriate on the power stroke, thus helping eliminate exhaust valve wear and tear.

The problems with Tetraethyl lead were known even before major oil companies began using it. In 1922, while plans for production of leaded gasoline were just getting underway, Thomas Midgley received a letter from Charles Klaus, a German scientist, stating of lead, “it’s a creeping and malicious poison” and warned that it had killed a fellow scientist. This didn’t seem to faze Midley, who himself came down with lead poisoning during the planning phase. While recovering in Miami, Midgley wrote to an oil industry engineer that public poisoning was “almost impossible, as no one will repeatedly get their hands covered in gasoline containing lead…” Other opposition to lead came from a lab director for the Public Health Service (A part of the US Department of Health and Human Services ) who wrote to the assistant surgeon general stating lead was a “serious menace to public health”.

Despite the warnings, production on leaded gasoline began in 1923. It didn’t take long for workers to begin succumbing to lead poisoning. At DuPont’s manufacturing plant in Deepwater New Jersey workers began to fall like dominoes. One worker died in the autumn of 1923. Three died in the summer of 1924 and four more in the winter of 1925. Despite this, public controversy didn’t begin until five workers died and forty-four were hospitalized in Oct. of 1924 at Standard Oils plant in Bayway NJ.

The Public Health Service held a conference in 1925 to address the problem of leaded gasoline. As you would expect, Kettering testified for the use of lead, stating that oil companies could produce alcohol fuels that had the benefits that were provided by lead, however the volumes needed to supply a growing fuel hungry society could not be met. Alice Hamilton of Harvard University countered proponents of leaded gasoline and testified that this type of fuel was dangerous to people and the environment. In the end, the Public Health Service allowed leaded gasoline to remain on the market.

In 1974, after environmental hazards began to become overwhelmingly apparent, the EPA (Environmental Protection Agency) announced a scheduled phase out of lead content in gasoline. One way manufacturers met these and other emission standards was to use catalytic converters. Catalytic converters use a chemical reaction to change pollutants, like carbon monoxide and other harmful hydrocarbons, to carbon dioxide, nitrogen and water. Tetraethyl lead would tend to clog up these converters making them inoperable. Thus, unleaded gasoline became the fuel of choice for any car with a catalytic converter.

The requirements by the EPA, emission control mechanisms on cars, and the advent of other octane boosting alternatives spelled the end for widespread leaded gasoline use. Manufacturers soon found that cars could no longer handle such a fuel; public tolerance of the environmental and health hazards would not allow it; and it became cost prohibitive to continue producing it. On January 1, 1996, the Clean Air Act completely banned the use of leaded fuel for any on road vehicle. Should you be found to possess leaded gasoline in your car you can be subject to a $10,000 fine.

This hasn’t completely gotten rid of leaded gasoline. You are still permitted to use it for off road vehicles, aircraft, racing cars, farm equipment, and marine engines, in the United States.

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Bonus Facts:

  • Since the banning of leaded gasoline for the majority of uses in the United States, the average level of lead in the blood of Americans has decreased by over 75%. This is particularly significant as the negative effects of lead when introduced into the human body are far reaching, extremely severe, and potentially permanent. The half-life of lead in the body is also quite long- weeks in your blood, months in your soft tissues, and years in your bones. Further, unlike many other poisons, according to the Centers for Disease Control and Prevention, “No safe blood lead level has been identified.”
  • In 1985, the EPA estimated that over 5,000 Americans died every year from heart disease caused by lead poisoning.
  • In 1988, a report was given to Congress by the Agency for Toxic Substances and Disease Registry on childhood lead poisoning in America. It concluded that every year from 1970-1987, as the EPA’s phase out of lead in gasoline was taking place, 2 million children a year had their blood-lead levels reduced to below toxic levels. The report estimated that, from 1927-1987, a total of 68 million children had a toxic exposure to lead from leaded gasoline.
  • Since lead is a naturally occurring heavy metal, unlike carcinogens like pesticides, waste oils and radioactive materials, it will not break down over time. It does not vaporize or disappear.
  • Just because you seem healthy does not mean you do not have high levels of lead in your blood. Signs and symptoms usually don’t present themselves until the accumulation of lead has reached dangerous amounts.  These signs and symptoms include: High blood pressure, declines in mental functioning, pain, numbness and tingling of the extremities, muscular weakness, headache, abdominal pain, memory loss, mood disorders, reduced sperm count, abnormal sperm, and miscarriage or premature birth in pregnant women.
  • Treatment for lead poisoning consists of treatment for symptoms and the use of Dimercaptosuccinic acid, which is an organosulfur compound, or Dimercaprol, also known as British anti-Lewisite.
  • On October 27, 2011, the United Nations Environment Program announced that the global use of leaded gasoline would be eradicated by 2013. The use of leaded gasoline is still allowed in 6 nations. These nations are Afghanistan, Algeria, Iraq, North Korea, Myanmar and Yemen. The U.N. is assisting those nations in a phase-out of its use.
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  • An excellent article.

    I remember my father talking about “ethel” petrol when he was a young man. Its incredible to think that those of us who grew up in the 50’s 60’s , as vehicles increased on the road, – we were all being poisoned. A lot of old houses had lead water pipes too.

  • Fantastic write up.

    Growing up in the 50’s 60′ was probably the worst. Then if you were a car enthusiast like me in your teens who tinkered in the garage tuning cars and fixing the bodies up by lead loading I just hope not too much long term damage.

    Certainly added myself to the daily tips subscription at least that will keep my mind active and maybe not forget so many things.

    It all starts with forgetting where you put the car keys, then later on in life it is the spectacles too, then life comes near the end when you can’t find your laptop

  • Great article. I’m not questioning the veracity of any of the statistics, but I do wonder how lead blood levels have been affected by removing lead from paint. In other words, is the 75% decrease just from removing lead from gas?

    • When reading this article, the same thought came to my mind (the variable of lead paint). However, when I thought about it a little more, I realized that the timing of the ban on leaded gas and the reduction of lead in people’s blood is significant. Also, just because the government banned the sale of lead paint doesn’t mean that there was a significant decrease in homes containing lead paint. Similarly, when asbestos was banned from new homes, the homes already containing asbestos didn’t get rid of the dangerous substance.

      Although this makes it difficult to conclude the exact amount of reduction that is due to the regulations of gasoline, these regulations were definitely the largest contributor to the reduction. Moreover, we need “big government” to protect us from unscrupulous industries that knowingly harm the general public. Whether it’s the oil industry poisoning the air, the paint industry poisoning our homes, or the patent medicine industry selling “cure-alls” containing opiates and cocaine poisoning our minds (and the list goes on and on), we NEED government regulation.

      • the govt did knew about the lead issues for 50 years and did nothing, yeah thats sound big govt

      • We also need professionals in fields go to school figure shit out and tell us about what it is so we can make the proper changes. Government regulation or not still is inevitable for a change. Regulations for the most part are all safety first principle. If you find something unsafe report it and make it known. Effective communication . mandate bans on regs for production and controls by need government . But of course Thats why they fund everything like science and r and d and all kinds of everything. Cool government.

  • Iodine was the first anti-knock substance to be used to prevent engine knock. It was far too expensive, so lead tetraethyl was developed to replace it.

    The decision to use catalytic converters was made to reduce the amount of unburned hydrocarbons in car exhaust; lead was destructive to early converters, and was the main reason for the elimination of lead in gasoline, not health concerns. All automobiles made after the 1975 model year had to run on unleaded gasoline.

  • I don’t know if articles are ever revised, or if there’s an age cutoff, but this sentence (starting… I guess technically the fourth paragraph) is particularly tortured:

    “The higher the compression in the cylinders a car’s motor can produce, the greater the power it can get out of each stroke of the piston.”

    I’d suggest, “The higher the compression a car’s motor can produce in its cylinders, the greater the power it can get out of each stroke of the piston.”

  • I’m curious about one point the article didn’t address. Originally the lead was added to decrease engine knock due to engine make-up. Wouldn’t there have been a point where engine manufacturing technology caught up and produced no-knock engines without the need for lead?

    • Yeah, engines can have no-knock characteristics. They also have no-power characteristics. In fact, the knock sensors on most modern vehicles pull ignition timing, which directly reduces power output. The knock related problem is just a function of compression.

  • Too bad. Leaded gasoline smells the best.

    • LOL ! I was thinking the same … when I was a kid in 70’s I used to love the smell of the burned gas out of those old klunkers (which looked like the best of the future)…

    • Damn straight, I remember the smell of 4-star growing up – it was sweet! I guess I’m supposed to be suffering from lead poisoning now as a result!

  • I have a 1930 Ford Model A. It will require leaded gasoline in order to operate without the knocking etc. The valves can be replaced with better ones but I know you can get a lead additive for your fuel. I simply can’t find it here in Panama. I am not sure but someone said you can add a cap full of oil to your gasoline and eliminate the problems you get from unleaded gasoline. I wonder if this is true.

  • Just a thing, it’s iso-octane and n-heptane.

  • Leaded gas also had lubricative qualities, the vaporized lead would adhere to metal components and create a barrier much like graphite lubricant does inside a lock. People wonder why motors don’t last a long time anymore, it’s because the fuel today is more like solvent, stripping the metal of any lubricant and causing wear. I have seen cylinder walls of motors from the 50’s and 60’s, with 3-4 hundred thousand miles that look like they’re brand new. No scoring, practically no wear whatsoever. And then you look at some new motors with not even a hundred thousand and they’re showing borderline catastrophic wear. Of course there’s no question that putting vaporized lead into the air is a health hazard, but in my opinion the best solution would have been capturing that pollutant and not allowing it to go into the air, not removing it from fuel.

    • Totally agree , with someone that gets it, the Govt. give up studies they want us to see, and now we have Ethanol, give me a frickin break, I worked for the company that made Lead, it helped with the lubrcation, it was not that bad . But it always comes down to Money and Greed as usual….

    • In the ’50’s -’60’s it was amazing if you got 100,000 miles out of an engine. In ’77 a ’57 chevy was a really old car. Today 300,000 miles is not at all unusual. Saying engines lasted longer back in the olden days is a fantasy.

    • interesting, i was wondering about lead being overblown. The benefits sounded potentially good and I remembering cars lasting much longer than they do now.

      But very shrewd of you to say we should capture the lead while still using it.

    • Ive seen the inside of a modern engine!, but 300k no oil change in 60k, severe overheating(beyond heat redline several times for 5+ mins)
      It looked pristine! Thats pretty much the case on any engine thats ever had an oil change. Engine wear takes a long time to affect anything, and you cant see it, you can see sludge and carbon buildup. But that car, pristine looking engine? I can move it about 4ft before it stalls, since its running 2 cylinders, as the other 2 lost all compression. But they look great! Modern engine failure is usually manufacturer or user error, properly maintained the car will fall apart before the engine fails. Last time I heard of an engine blowing, was my friends camry with 600-700k miles. But transmissions? They do not last and I can see why someone may think older cars last longer, and thats simply because manual transmissions were more common then, and transmission issues are usually a total loss with automatics, most of the time even now, rebuilt is even more reliable than new manual transmissions. But you also need to replace the clutch more often, and it might as well be the same damn thing as replacing the transmission, so its not like you are somehow winning. And if you go too long with a bad clutch? You will lose the transmission. To classify manual cars as “more reliable”, even though totaling them from transmission failure isnt common, is just a straight up lie because they arent, and its incredibly easy to screw up half your drivetrain because you didnt realize your clutch was failing until the car wouldn’t move. (And experienced manual drivers are a lot more likey to do it, since they dont use the tach)

  • I’m confused. Gasoline refined had no lead in it. Prices where jacked up when the lead was added. Then gas was jacked up for no-lead. What happen people. Look it up.

  • Tetraethyl lead was used to raise the octane in gasoline to stop knocking, but it didn’t stop the wear and tear, it caused more problems. Bromide had to be added to the tetraethyl lead to stop the problems.

  • Before people knew it was poisonous, lead oxide was used to polish jewelry, brass and silver. It was used for that purpose because it’s abrasive. They use finely powdered garnet now instead. I find it hard to believe the same material is also a lubricant. Suspect another additive was used along with the tetra-ethyl lead.

  • can you use leaded gasoline in outboard motors?

  • I remember back in 1983 my local news radio station announced that they were banning leaded gasoline because they said it was giving African Americans brain damage I don”t see how it could just give African Americans brain damage I would think that it would give everyone brain damage the only way that it would just give African Americans brain damage is if they were drinking it what they said did not make any sense to me.

  • Lead was never a lubricant in engines! It actually bunged the valve guides up and with tungsten valves there were no need for it! The governments actually wanted to spread lead through all the environments even our bodies! It protected us from a nuclear war radiation! Even though it made the society mentally retarded. They did the same by adding chlorine to water during ww1 becuase of chlorine gas! This made is imine to the gas attacks! You all are so niave and blind!

  • The use of lead in gasoline (and paint) was an incredible public health disaster for the US. Look up the work of Rick Nevin and colleagues. All of this happened because tetraethyl lead was a lucrative patent. Even ancient Greeks knew this stuff was poisonous.

  • we have the ability to build the best cars in the world, during the 60 and 70 ties Amoco built a bias tire that would last more than 250000 miles. my dad and me had a set after 15 years and 150000 miles the tires should know wear.at one time a company made a v4 engine it ran under load for 2 years 24 hours aday getting 87 miles per gallion. of course we knew about electronic fuel injection in 1955, why do people think efi is new. we new about electric injection in 1922. if you would like to contact me

  • There are a couple of facts in there I might dispute, but I’m not going to get into that. I graduated High School in 1990 (Yes, I’m old). Just out of high school I took the stock motor out of my 66 Mustang and built a high-performance 289, forged pistons, and a few tuner tricks I won’t divulge., I ran leaded gasoline through it at $0.79/gal. I drove that car EVERYWHERE! That gas ran GREAT! Switching to unleaded dropped performance a little. I just drove that same Mustang, same engine to In-N-Out for dinner tonight, it still runs great! There is probably so much lead built up in that engine it is still acting as a catalyst or something (I’m no chemist). When we would taker an engine apart the pistons, black, everything was BLACK. Now days an engine is very clean inside!!!

  • Radioactive materials are naturally occurring — e.g., radon in your basement or potassium-40 in your body and in the bananas you just bought at the supermarket.

  • Since it’s relevant (even though lead’s been out of gas for years:) I was reading that Garlic can help reduce Lead levels in Blood by a considerable amount. I’m not sure if that’s Raw (fresh from the clove,) Raw (in a jar, but missing freshness) or Cooked Garlic. Anyone who may have lead in their blood should look into this.