This sound was discovered to be "Pinging" or sometimes called engine knocking. The sound was like somebody had put gravel rocks in the cylinders! Besides the very undesirable sounds that were produced from the relatively new technology it was discovered that pinging caused damage to the internal workings of the engine itself. Some solution had to be found or this technology would never be accepted!
So in 1916 a chemist, named Thomas Midgley, was given the job of finding a solution to this particular problem. He was told that not only was it bad for the automobiles being produced but the newfangled flying machines and the associated aviation engine development was being hampered. So working for General Motors Research, he tried several schemes to prevent this engine knock.
Since Thomas thought that too much heat might be the problem, he tried different dyes in the gas. Perhaps different colors would absorb less heat. This didn't work out so well. They then accumulated almost every element they could think of based on the Periodic Chart of the elements and started going down the list.
By trial and error, they stumbled upon a substance called Tetra-Ethyl-Tin that showed some promise. Further investigation showed that it was the lead in the Tetra-Ethyl-Tin that stopped the knock completely. Lead was extremely cheap so if this substance worked out, a lot of money could be made. The chemist cooked up a batch of Tetra-Ethyl-Lead and tried it out. The knock went away completely like magic!
But by this time, other researchers had discovered that lead had some very bad properties like brain damage, strange skin reactions, difficulties in walking, etc. The League of Nations recommended to ban all lead in paint to which Europe complied.The United States, for whatever reason, did not regulate lead in paint until a much later date. Thomas Midgley was by then receiving all sorts of reports and letters telling about the hazards of lead but by this time too much had been invested in this magical liquid solution.
In 1922, the surgeon general wrote a letter to the president of General Motors with concerns that lead would become a serious health issue to the public. In spite of these warnings, the president of General Motors, Pierre DuPont partnered with Standard Oil to form Ethyl Gasoline Company with Mr. Charles Kettering as President and Thomas Midgley, the chemist, as Vice-President. The product was put on sale in 1923. Additional public advertising was helped by the fact that Ethyl fueled cars won 1st, 2nd, and 3rd place at the Indianapolis Raceway in 1923.
But problems started to show up. At the Ethyl production facility in Deepwater, the workers became disoriented, had a strange gait, and couldn't seem to think clearly. The Deepwater Ethyl plant started to be called the "House of Butterflies" for the strange effects to the workers. The companies leaders excused the effects as the workers are "working too hard" and that was causing the slow insanity. "We are going to have to protect the workers against themselves" stated Mr Kettering. The public took these statements as a clean bill of health and soon the Ethyl lead additive started taking over the market.
By 1963, over 98 percent of all gasoline contained the additive. But all this lead was also coming out of the exhausts of all those cars across the country. Thousands of tons of lead per year at its peak. But because of political muscle, Ethyl lead gasoline enjoyed the protection of the government. One instance, when a competitor came up with a nonlead additive, the US government actually sued them into bankruptcy. The US Federal Trade Commission came out with a report that stated that leaded gas was not a narcotic, poisonous dope, or dangerous to human health in any way. Ethyl Gasoline was here to stay........except for one person who just wouldn't go along.
This one geochemist graduate student, Clair Patterson, was trying some new ways of measuring how old rocks were with the goal of finding out how old the earth was. His new method was by measuring the isotopes of uranium and lead naturally found in rocks samples. But something was wrong! All of the rock samples he tested contained about 200 times the amount of lead they should have naturally. He just couldn't figure out where the contamination was coming from! He set up a strict contamination procedure in his lab. Still he was coming up with the same results. Where was all the lead coming from?
He found out that the lead contamination was from the atmosphere and spoiling the samples. He then discovered that it was from the gasoline additive, Tetra-Ethyl-Lead, and started publishing his findings.
Dr Patterson came up with an experiment in which he would take core samples from pack ice in Greenland and from the different layers, be able to determine lead contamination throughout past years. The experiment worked and it show that lead levels started increasing in 1923 and that the last tested year of 1965, the lead levels were 1000 times what they had been before 1923.
He also started testing human bones and found that modern human bone lead level were many times greater than pre-1923 bone lead tests. When these results were published, the proverbial "crap hit the fan".
First the Ethyl corporation offered him lucrative contracts for more favorable results. He refused. They then started a public smear campaign designed to destroy his credibility. Even the US government got into the campaign with the National Research Council disputing the findings. The Ethyl Corporation had many friends on their side including a Supreme Court Justice, members of the US Public Health Service, and the American Petroleum Institute.
But Dr. Patterson would not relent on his campaign to inform the general public. Eventually Congress passed the Clean Air act of 1970 which demanded that leaded gasoline was to be phased out because of research that Dr Patterson published. DuPont and the Ethyl Corporation were able to delay the death of Ethyl based additives for 10 more years in court, but eventually all gasoline became lead free in 1986. In the 63 years of Ethyl additives existence, 6 million tons of lead was released in the atmosphere.
What happened to the chemist, Thomas Midgley, who ignored all the warnings about lead and came up with Ethyl additives? Well, he was not totally out of the creative process when Tetra-Ethyl-Lead ceased to exist. He later went on to invent ChloroFluroCarbons, otherwise known as CFC'S. What a guy!!
Resources:
The Nation: The Secret History of Lead by Jamie Kitman
Wikipedia: http://en.wikipedia.org/wiki/Tetra-ethyl_lead
Damn Interesting: The Ethyl Poison Earth by Alan Bellows
http://www.chemcases.com/tel/tel-13.htm
Kenneshaw University "How the best known Poison on Earth remained in the Gasoline Supply for 60 Years"